Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B25/00—Engines characterised by using fresh charge for scavenging cylinders
  • F02B25/02—Engines characterised by using fresh charge for scavenging cylinders using unidirectional scavenging
  • F02B25/04—Engines having ports both in cylinder head and in cylinder wall near bottom of piston stroke
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/01—Internal exhaust gas recirculation, i.e. wherein the residual exhaust gases are trapped in the cylinder or pushed back from the intake or the exhaust manifold into the combustion chamber without the use of additional passages
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/02—EGR systems specially adapted for supercharged engines
  • F02M26/04—EGR systems specially adapted for supercharged engines with a single turbocharger
  • F02M26/05—High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
  • F02M26/17—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories in relation to the intake system
  • F02M26/20—Feeding recirculated exhaust gases directly into the combustion chambers or into the intake runners
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
  • F02M26/34—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with compressors, turbines or the like in the recirculation passage
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
  • F02M26/41—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories characterised by the arrangement of the recirculation passage in relation to the engine, e.g. to cylinder heads, liners, spark plugs or manifolds; characterised by the arrangement of the recirculation passage in relation to specially adapted combustion chambers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
  • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
  • F02M26/42—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories having two or more EGR passages; EGR systems specially adapted for engines having two or more cylinders
  • F02M26/43—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories having two or more EGR passages; EGR systems specially adapted for engines having two or more cylinders in which exhaust from only one cylinder or only a group of cylinders is directed to the intake of the engine

Definitions

• the disclosure relates generally to an internal combustion engine system for a vehicle.
• the disclosure can be applied to heavy-duty vehicles, such as trucks, buses, and construction equipment, among other vehicle types.
• heavy-duty vehicles such as trucks, buses, and construction equipment
• the internal combustion engine system may e.g. be applicable for other types of vehicles propelled by means of an internal combustion engine such as cars and other lightweight and light-duty vehicles etc.
• the internal combustion engine system may likewise be applicable in marine vessels and the like.
• the internal combustion engine of the internal combustion engine system may typically be a two-stroke internal combustion engine operable on a hydrogen-based fuel.
• an internal combustion engine (ICE) system for a vehicle.
• the ICE system comprises a two-stroke ICE operable on a fuel.
• the ICE has at least one cylinder with a cylinder wall and further a reciprocating piston moveable in an axial direction within the cylinder between a bottom dead center BDC and a top dead center TDC, the at least one cylinder at least partly defining a combustion chamber with a top end of the piston; a first intake manifold for receiving fresh air, the first intake manifold configured to be in fluid communication with a first intake port arranged at a top end of the at least one cylinder, the first intake port configured to be in fluid communication with the combustion chamber; an exhaust port arranged axially distal from the top end of the at least one cylinder, allowing the first intake port and the exhaust port to be fluidly separated by the piston; a second intake manifold configured to be in fluid connection with an exhaust gas recirculation EGR system, the second intake manifold further being configured to
• the first aspect of the disclosure may seek to provide an improved two-stroke ICE system in terms of enhanced performance and efficiency by reducing, or even minimizing, gas exchange losses and further facilitating the control of the combustion process.
• the proposed ICE system is configured as a two-stroke engine, which inherently needs efficient handling of exhaust gases to enhance overall engine efficiency.
• the proposed ICE system comprises the integration of an exhaust gas recirculation (EGR) system with a dedicated EGR inlet control valve in fluid communication with the combustion chamber.
• EGR exhaust gas recirculation
• a technical benefit may include providing a controlled introduction of recirculated exhaust gases back into the combustion chamber.
• the inclusion of the EGR system in the two-stroke ICE system may serve multiple purposes. Firstly, the EGR system may allow for reducing gas exchange losses. By effectively managing the flow of exhaust gases, the ICE system may reduce the loss of unburned fuel and air during the gas exchange process. This may be particularly useful in two-stroke engines, where the overlap of intake and exhaust events can lead to significant losses. The EGR system may allow for recirculating exhaust gases more efficiently, thus reducing these losses.
• the EGR system with the positive displacement device allows for more accurate metering of the exhaust gas recirculated into the combustion chamber.
• Such control of the exhaust gases may help in maintaining the desired combustion conditions, leading to improved fuel efficiency and reduced formation of harmful emissions such as NOx.
• the ability to regulate the amount and timing of EGR introduction through the dedicated EGR control valve may also enhance the stability and completeness of the combustion process.
• the combination of reduced gas exchange losses and improved combustion control will provide higher overall engine efficiency.
• the ICE system may allow for reducing the peak combustion temperatures, which in turn may reduce the tendency for knock, thus improving thermal efficiency.
• the use of the positive displacement device in the EGR system for a two-stroke ICE may ensure that the recirculated gases are adequately pumped back into the cylinder after being cooled, thereby maintaining consistent and efficient operation.
• the combustion temperature can be controlled using EGR to reduce NOx formation and contribute to the longevity of components in the combustion chamber (piston, valves, etc.). Furthermore, a more controlled combustion at a moderate temperature results in a reduction of heat losses in the engine (to the coolant).
• the proposed ICE system may provide an EGR system tailored for a two-stroke ICE, which may allow for reducing gas exchange losses within the ICE system and for more fine-tuned control of the combustion process, thus providing higher engine efficiency and reduced emissions.
• the corresponding piston By arranging the intake and exhaust ports of the cylinders at different positions, the corresponding piston creates a blocking effect between these ports when it reaches its top dead center. Such configuration ensures that the hotter parts of the cylinder, such as the exhaust port and the cylinder wall or liner, are completely isolated from the combustible gas, typically an air/fuel mixture.
• the proposed ICE system enables a length-scavenging system that separates the hot exhaust end of the cylinder from the cold intake end where the combustibles are present. Therefore, the knock risk may be drastically reduced with the proposed ICE system.
• the proposed ICE system provides for suppressing the tendency for knock and/or self-ignition of the fuel, such as a gaseous fuel, e.g. hydrogen-based fuel.
• the proposed two-stroke ICE favorably operable on hydrogen, or any other gaseous fuel, provides for increasing the BMEP potential due to twice the firing frequency.
• the two-stroke cycle enable the ICE to operate at a higher lambda with a maintained power density, as compared to four stroke ICEs.
• a "two-stroke operation” or “two-stroke mode” refers to a cycle of the internal combustion engine, in which the piston moves two strokes (up and down movements) between the TDC and the BDC during only one crank shaft revolution so as to complete a full work cycle.
• the operation of the internal combustion engine when operated in a general two-stroke operation corresponds to a repetitive engine operation every crank shaft revolution.
• the fuel may be a gaseous fuel, a liquid fuel or a combination thereof, e.g. a dual fuel having a first fuel and a second fuel.
• the first intake port and the exhaust port are located at different positions and fluidly separated by the piston top end when the piston is in the upper part of the cylinder.
• the first intake port and the exhaust port are located at different positions and fluidly separated by the piston top end when the piston is in its top dead center.
• the fluid communication between the combustion chamber and the exhaust port is controlled by a position of the piston, typically corresponding to an axial position of the piston along the axial direction.
• the temperature of the EGR gas can be reduced to a suitable temperature before entering the combustion chamber(s) of the ICE.
• the temperature of the EGR gases can be reduced to a suitable temperature before entering the combustion chamber(s) of the ICE.
• the EGR cooler may also provide for dehumidifying receiving EGR gas, which may be particularly useful for hydrogen ICE engines as the exhaust gases contain water as a combustion product.
• the positive displacement device may be controllable in response to an operational parameter of the ICE system.
• a technical benefit may include the ability to dynamically adjust the amount of EGR based on real-time engine conditions, leading to enhanced combustion and reduced emissions under various operating conditions.
• By controlling the positive displacement device in response to the operation of the ICE system a more accurate and rapid control of the charge mass (EGR and air) composition can be achieved. This control of the positive displacement device enhances the overall management of the ICE system, improving transient control, knock control, and emission control.
• the operational parameter of the ICE system may be any one of engine load, engine speed, and exhaust temperature.
• a technical benefit may include more precise control of EGR flow by responding to specific engine parameters, which helps maintain enhanced combustion efficiency and reduces the formation of NOx and other pollutants.
• the ICE system may be configured to operate at a target lambda value of about one.
• a technical benefit may include achieving stoichiometric combustion, which typically increases, or even maximizes, fuel efficiency and reduces, or even minimizes, emissions by ensuring an ideal air-to-fuel ratio.
• the EGR system provides for regulating the temperature to a tolerable level.
• a lambda value may typically be indicative of a ratio between an amount of air and an amount of fuel in a combustion chamber of an engine.
• the target lambda 1 thus refers to a target air-fuel equivalence ratio of 1, and may be determined by the ratio of actual air-fuel ratio (mass of air to fuel) to stoichiometric air-fuel ratio, for a given mixture.
• the target lambda is essentially 1.
• the ICE system may be configured to operate at a target lambda value of about one, i.e. about 1, by controlling the positive displacement device in response to the operational parameter of the ICE system.
• the ICE system may further be configured to control the fuel injection rate and the air intake.
• the ICE system can maintain the air-fuel mixture at, or near, the stoichiometric ratio. Adjusting the air intake may further help the ICE system to maintain the desired air-fuel ratio.
• the ICE system may further use one or more oxygen sensors (02 Sensors), also known as lambda sensors.
• the lambda sensors are located in the exhaust duct and arranged to provide real-time feedback data on the oxygen content of the exhaust gases.
• the ICE system may comprise a turbocharger arrangement having a turbocharger turbine operatively connected to a turbocharger compressor, wherein the turbocharger compressor is arranged in an air intake conduit to the first intake manifold, and wherein the turbocharger turbine is arranged in the exhaust duct so as to drive the turbocharger compressor.
• the positive displacement device in the EGR flow in the EGR system complements the air flow from the turbo with accurate EGR levels during all conditions (also transient) for improved performance in terms of temperature, knock control and NOx formation.
• the EGR conduit may be adapted to connect to the exhaust duct at a position upstream of the turbocharger turbine.
• a technical benefit may include enhanced efficiency in EGR gas recirculation by utilizing higher pressure exhaust gases before the exhaust gases pass through the turbocharger, improving the EGR system's effectiveness (less power is needed to move the EGR into the ICE).
• the EGR control valve may be controllable to purge the at least one cylinder from combusted gas after an ICE work stroke by supplying EGR gas to the combustion chamber via the second intake port.
• a technical benefit may include improved purging of residual exhaust gases, which can reduce knock and improve combustion stability and efficiency in the subsequent cycles. Purging with EGR instead of air/fuel mixture mitigates the risk of the air/fuel mixture to slip out through the exhaust port. To this end, the warm residuals (exhaust) are replaced by cool residuals (EGR).
• the EGR control valve may be configured to be controllable by an actuator of a variable valve actuation system.
• a technical benefit may include precise timing and control of the EGR valve operation, enhancing the flexibility and responsiveness of the EGR system to varying engine conditions.
• the second intake port may be a swirl intake port configured to create a swirling motion of the fluid medium.
• a technical benefit may include improved air-fuel mixing in the combustion chamber, which leads to more efficient combustion and reduced emissions.
• the use of a swirl intake port can reduce (i.e. improve) heat losses in the cylinder by having cold EGR closest to the cylinder liner and cylinder head, thereby limiting the amount of oxygen/ air that combust close to the cylinder walls.
• the at least one cylinder may further comprise an evacuation port arranged at the top end of the at least one cylinder, the evacuation port being configured to be in fluid communication with the combustion chamber, and a controllable evacuation valve disposed in the evacuation port and configured to provide engine braking by controlling the flow of fluid medium through the evacuation port.
• a technical benefit may include a more efficient engine braking operation for a two-stroke ICE engine, enabling better vehicle control.
• the term "fluid medium" may refer to a compressed gas fluid medium, compressed air, exhaust gas, or a mix thereof.
• controllable evacuation valve may be controllable in cooperation with the movement of the piston such that the controllable evacuation valve permits evacuation of fluid medium from the combustion chamber via the evacuation port during a compression stroke.
• a technical benefit may include enhanced timing precision of engine braking, contributing to improved fuel efficiency and reduced emissions.
• controllable evacuation valve may be controllable in cooperation with the movement of the piston such that the controllable evacuation valve skips evacuation of fluid medium from the combustion chamber via the evacuation port for a given crankshaft revolution.
• a technical benefit may include the ability to dynamically adjust engine braking intensity, allowing for smoother deceleration and enhanced engine performance under varying load conditions.
• the ICE controllable evacuation valve may be configured to be controllable by an actuator of a camshaft-driven valve actuation system.
• a technical benefit may include improved reliability and durability of the engine braking mechanism by a mechanical camshaft system.
• controllable evacuation valve may be configured to be controllable by an actuator of a variable valve actuation system.
• a technical benefit may include enhanced flexibility in engine braking control, enabling more precise management of vehicle deceleration.
• the ICE system may be a spark-ignition ICE system, and the at least one cylinder having an ignition source arranged in the combustion chamber.
• a technical benefit may include precise control over the ignition timing and improved combustion efficiency, which can lead to better performance and lower emissions.
• the ignition source may be any one of a spark plug and a glow plug.
• the ICE system comprises a fuel injector arrangement for injecting fuel, the fuel injector arrangement being arranged in the combustion chamber, or the fuel injector arrangement being arranged upstream of the first intake port to provide a port fuel injection arrangement.
• a technical benefit with the fuel injector arrangement being arranged in the combustion chamber may include enhanced fuel delivery for improved combustion efficiency.
• a technical benefit with port fuel injection arrangement may include enhanced fuel delivery for improved combustion efficiency. The use of a port injection allows for providing a homogenous mixture which enables an improved knock and auto-ignition control and also contributes to reduce the emissions.
• the flow of intake gas through the first intake port may be controllable by a controllable intake valve.
• a technical benefit may include the ability to precisely control the air-fuel mixture, further enhancing engine efficiency and performance.
• the at least one cylinder may be a first cylinder and the piston may be a first piston
• the ICE further having a second cylinder forming a pair of cylinders with the first cylinder, the second cylinder accommodating a corresponding reciprocating second piston operable between a bottom dead center and a top dead center, and further at least partly defining a second combustion chamber with a top end of the second piston
• the second cylinder further comprises a corresponding ignition source arranged in the second combustion chamber, at least one corresponding intake port arranged at a top end of the second cylinder and in fluid communication with the second combustion chamber, and further a corresponding exhaust port arranged axially distal from the top end of the second cylinder, allowing the at least one corresponding intake port and the corresponding exhaust port to be fluidly separated by the second piston.
• the first and second cylinders may be separated from each other with a crank angle of 180 degrees.
• the two cylinders can provide a 180 degrees cycle separation irrespectively of the ICE and cylinder arrangement/configuration.
• the pair of first and second cylinders may be arranged separated from each other with a crank angle of 180 degrees, so as to provide a 180 degrees combustion phasing separation.
• the first intake manifold may have a corresponding positive displacement device configured to receive and feed intake air to the pair of cylinders, the corresponding positive displacement device further being arranged in the air intake manifold to separate an upstream intake tract from a downstream plenum of the first intake manifold, the downstream plenum being in fluid communication with each one of the first and second cylinders of the pair of cylinders.
• a technical benefit may include improved air management and distribution, leading to more efficient combustion and enhanced engine performance.
• the displacement device is arranged to eliminate, or at least reduce, the risk of having pressure pulses transferred backwards from the combustion chambers to the upstream intake tract of the air intake manifold.
• the intake ports are mechanically isolated from the intake tract.
• the corresponding positive displacement device is thus arranged to seal the cylinders and the downstream intake plenum from the upstream intake tract of the air intake manifold (intake duct) in case of backfire. Also, by the arrangement and configuration of the displacement device in the air intake manifold, the displacement device can still provide an even flow by the alternating feed to the cylinder pair.
• the ICE system may thus provide a separate intake plenum for each pair of cylinders with a 180 degrees combustion phasing separation, where the intake manifold has a close coupled corresponding positive displacement device for each pair of cylinders.
• Such ICE system may contribute to reducing time-to-ignition with decreased risk of having backfiring into the induction system of the ICE system.
• the proposed ICE system may not be restricted to a system with one single pair of cylinders, but can also be implemented in four cylinders, six cylinders etc. Hence, the proposed ICE system may have a minimum of two cylinders, but multiples of two cylinders may be possible.
• controllable intake valve of the first cylinder may be controllable in correlation with the movement of the first piston and the controllable intake valve of the second cylinder is controllable in correlation with the movement of the second piston such that fluid communication between the respective combustion chambers and the downstream plenum being selectively opened and closed during a crank shaft revolution of the ICE.
• a technical benefit may include synchronized air intake with piston movement, improving air utilization and enhancing engine efficiency.
• the ICE system may be a hydrogen ICE system configured to operate on a gaseous fuel containing a hydrogen-based gaseous fuel.
• a technical benefit may include reduced environmental impact due to lower CO2 emissions compared to traditional hydrocarbon fuels, aligning with global sustainability goals.
• Hydrogen-based fuel may typically have a high auto-ignition temperature, however, low ignition energy may only be needed if a spark (or glowing surface or particle) is present. The low ignition energy may, however, pose some challenges on the ICE, e.g. it may be difficult to use a cylinder head where the hot exhaust ports/valves are located in the same combustion chamber as the intake ports/valves or in the vicinity of the compressed air/ fuel mixture prior to ignition.
• a technical benefit of the proposed ICE system for use with a hydrogen-based fuel may include a more reliable and robust hydrogen ICE system.
• the ICE system may be beneficial for all force scavenged two strokes ICE systems, including, but not limited to compression ignited fuel engines, for example H2 ICE systems with diesel pilot injection in a two-stroke mode.
• the fuel may be a gaseous fuel.
• a gaseous fuel is a hydrogen-based fuel.
• the fuel is a liquid fuel.
• a liquid fuel is an NH3-based fuel.
• the plenum may comprise an air inlet configured to be in fluid communication with the corresponding positive displacement device and a plurality of outlets configured to be in fluid communication with the intake ports of the first and second cylinders.
• the ICE system may comprise a common crankcase housing for the pair of cylinders, or, the ICE system may comprise multiple set of pair of cylinders and the ICE system comprises a common crankcase housing for all cylinders of the ICE.
• each one of the controllable intake valve and the corresponding controllable intake valve may be arranged to open and close a fluid passage of the respective intake port, thus controlling the flow of fluid to the respective combustion chamber.
• controllable intake valve of the first cylinder may be controllable in correlation with the movement of the first piston and the controllable intake valve of the second cylinder may be controllable in correlation with the movement of the second piston such that fluid communication between the respective combustion chambers and the plenum being selectively open and closed during a crank shaft revolution of the ICE.
• a technical benefit may include to further reduce the risk of backfire.
• the plenum may comprise an air inlet in fluid communication with the corresponding positive displacement device and a plurality of outlets configured to be in fluid communication with the intake ports of the first and second cylinders.
• a technical benefit may include an improved air supply system for supplying air to the cylinders.
• the plenum is a Siamese-shaped design.
• any one of the positive displacement device and the corresponding positive displacement device may be a variable positive displacement device configured to be operated in a variable manner.
• the ICE system may further comprise additional pairs of cylinders with corresponding air intake manifolds and corresponding positive displacement devices.
• the exhaust ports may be arranged in fluid communication with an exhaust duct arranged to transport exhaust gas away from the cylinders.
• a vehicle comprising an internal combustion engine system according to the first aspect and/or according to any one of the examples of the first aspect.
• a technical benefit may include the integration of the ICE system into vehicles, offering improved efficiency, performance, and environmental benefits.
• the disclosure is at least partly based on the insight that when operating a vehicle, such as a heavy-duty vehicle, combustion temperatures are primarily controlled by diluted lean combustion.
• the dilution mainly contains air, which is sometimes complemented by recirculated exhaust gas (EGR).
• EGR recirculated exhaust gas
• ICE internal combustion engine
• the combustion of hydrogen gas occasionally produces high amounts of NOx due to elevated combustion temperatures when operated at low lambda levels, even if it is diluted to levels comparable to or above typical diesel lambda levels.
• hydrogen ICEs face challenges with autoignition and knock in situations with less dilution.
• ICE For the ICE itself, durability may be compromised when lower dilution is used, as the combustion and exhaust temperatures are too high for the materials typically employed in medium-duty (MD) and heavy-duty (HD) ICEs. There is thus a need to further improve ICE systems operable on a gaseous fuel, in particular a hydrogen-based fuel, such as hydrogen gas.
• a gaseous fuel in particular a hydrogen-based fuel, such as hydrogen gas.
• the disclosure seeks to provide an improved two-stroke ICE system in terms of enhanced performance and efficiency by reducing, or even minimizing, gas exchange losses and further facilitating the control of the combustion process.
• the proposed ICE system is configured as a two-stroke engine, which inherently needs efficient handling of exhaust gases to enhance overall engine efficiency.
• the proposed ICE system comprises the integration of an exhaust gas recirculation (EGR) system with a dedicated EGR inlet control valve in fluid communication with the combustion chamber.
• EGR exhaust gas recirculation
• a technical benefit may include providing a controlled introduction of recirculated exhaust gases back into the combustion chamber.
• the inclusion of the EGR system in the two-stroke ICE system may serve multiple purposes. Firstly, the EGR system may allow for reducing gas exchange losses. By effectively managing the flow of exhaust gases, the ICE system may reduce the loss of unburned fuel and air during the gas exchange process. This may be particularly useful in two-stroke ICE systems, where the overlap of intake and exhaust events (scavenging) can lead to significant losses. The EGR system may allow for recirculating exhaust gases more efficiently, thus reducing these losses. In addition, the EGR system with the positive displacement device allows for more accurate metering of the exhaust gas recirculated into the combustion chamber.
• Such control of the exhaust gases may help in maintaining the desired combustion conditions, leading to improved fuel efficiency and reduced formation of harmful emissions such as NOx.
• the ability to regulate the amount and timing of EGR introduction through the dedicated EGR control valve also enhances the stability and completeness of the combustion process.
• the combination of reduced gas exchange losses and improved combustion control may provide higher overall engine efficiency.
• the ICE system may allow for reducing the peak combustion temperatures, which in turn may reduce the tendency for knock, thus improving thermal efficiency.
• the use of the positive displacement device in the EGR system for a two-stroke ICE may ensure that the recirculated gases are adequately pumped back into the cylinder after being cooled, thereby maintaining consistent and efficient operation.
• the combustion temperature can be controlled using EGR to reduce NOx formation and contribute to the longevity of components in the combustion chamber (piston, valves, etc.). Furthermore, a more controlled combustion at a moderate temperature results in a reduction of heat losses in the engine (to the coolant).
• the proposed ICE system may provide an EGR system tailored for a two-stroke ICE, which may allow for reducing gas exchange losses within the ICE system and for more fine-tuned control of the combustion process, thus providing higher engine efficiency and reduced emissions.
• Fig. 1 is an exemplary embodiment of the present disclosure, comprising a side view of a vehicle 1, in the form of a truck, according to an example. Whilst the shown embodiment illustrates a truck, the disclosure may relate to any vehicle, such as a car, bus, industrial vehicle, boat, ship, etc., wherein motive power may be derived from an internal combustion engine.
• the vehicle 1 comprises an internal combustion engine system 10.
• the internal combustion engine system may generally herein refer to the ICE system 10.
• the vehicle 1 may also comprise a controller 90.
• the controller 90 is here part of a control system.
• the controller 90 may be part of the ECU of the vehicle 1.
• the controller 90 typically comprises a processing circuitry 91 configured to control the ICE system 10, as described herein.
• Figs. 2 to 4 illustrating an example of an ICE system. More specifically, Figs. 2 and 3 show an example of an ICE system 10, in which Fig. 2 is cross-sectional view of the ICE 20 and Fig. 3 is a perspective view of the ICE 20. Purely by way of example, the Figs. 2 and 3 of the ICE system 10 may be used in the vehicle 1 of Fig. 1 .
• the ICE system 10 comprises a two-stroke ICE 20.
• the ICE 20 is operable on a fuel, such as a gaseous fuel 50 (indicated in Fig. 3 ).
• the ICE 20 may in other examples be operable on a liquid fuel.
• a gaseous fuel is a hydrogen-based fuel.
• a liquid fuel is an NH3-based fuel.
• Other examples of liquid fuels are LNG, LPG, petrol, and the like.
• the ICE system 10 is here a spark-ignition ICE system.
• the spark-ignited two-stroke ICE 20 is operable on a hydrogen-based fuel.
• the combustion in such hydrogen ICE system 10 is based on a combustion of air and hydrogen, as is commonly known in the art. While the combustion of hydrogen with oxygen may only produce water as its only product in a pure combustion process between hydrogen and oxygen, a hydrogen ICE system 10 based on combustion of air and hydrogen generally produce water, heat and NOx, as is commonly known in the art.
• hydrogen can be combusted in an ICE 20 over a wide range of fuel-air mixtures.
• a hydrogen ICE system 10 may be operated to produce very low emissions during certain conditions.
• the hydrogen ICE system 10 may operate based on hydrogen liquid or hydrogen gas.
• the hydrogen ICE system 10 contributes to a leaner operation of the ICE 20, which is favorable from a NOx emission perspective.
• the ICE 20 comprises at least one cylinder 30 with a cylinder wall 30a.
• the at least one cylinder is a first cylinder 30 of the ICE 20.
• the ICE 20 comprises at least the first cylinder 30.
• the ICE 20 may typically comprise a number of cylinders, such as a pair of first and second cylinders, as illustrated and described in relation to Fig. 3 , or a multiple number of pair of cylinders.
• the cylinder 30 extends in an axial direction A (typically corresponding to direction Z of the ICE) and in a radial direction R (typically corresponding to direction X or direction Y of the ICE).
• the cylinder 30 also has an extension in a circumferential direction C.
• the cylinder wall 30a extends in the axial direction A and in the circumferential direction C.
• the cylinder wall 30a is an inner wall of the cylinder 30.
• the inner wall of the cylinder 30 is provided by a so called a cylinder liner, as is commonly known in the art.
• the cylinder wall 30a may thus be part of a cylinder liner.
• the cylinder 30 here also comprises a cylinder head 30b.
• the cylinder head 30b here defines an uppermost portion of the cylinder 30, as seen in the axial direction A.
• the cylinder head 30b may have an essentially flat bottom inner surface.
• Other examples of cylinder heads are also possible.
• the design of the combustion chamber may thus be provided in several different ways in view of the design of the cylinder head 30b.
• the design of the cylinder head 30b and the cylinder 30 in the figures are only provided for illustrating one example of the cylinder design.
• the ICE 20 further comprises a reciprocating piston 31.
• the reciprocating piston 31 is moveable in the axial direction A within the cylinder 30.
• the reciprocating piston 31 is moveable in the axial direction A within the cylinder 30 between the bottom dead center (BDC) and the top dead center (TDC).
• BDC bottom dead center
• TDC top dead center
• the reciprocating piston 31 may in the following be denoted simply as the piston for ease of reference.
• the ICE system 10 further comprises a crank shaft 27 and a connecting rod 28.
• the connecting rod 28 is operatively connected to the piston 31.
• the piston 31 may generally comprise a suitable number of piston rings.
• the piston 31 comprises one or more compression rings and oil control rings. The number of piston rings and type of piston rings are selected based on the fuel of the ICE system 10. In this example, the piston rings are arranged at a top end 33 of the piston 31.
• the reciprocating piston 31 further at least partly defines a combustion chamber 32 with the top end 33 of the piston 31.
• the combustion chamber 32 is arranged at the end portion, i.e. the cylinder head 30b, of the cylinder 30 so that an upper surface of the top end 33 defines a lower side of the combustion chamber 32.
• the cylinder 30 further comprises an ignition source 34.
• the ignition source 34 is arranged in the combustion chamber 32.
• the ignition source 34 is arranged in the cylinder 30 and at a location facing the combustion chamber 32.
• the ignition source 34 is arranged at an upper end of the cylinder 30, as illustrated in Fig. 2 .
• the ignition source 34 is arranged at the cylinder head 30b of the cylinder 30.
• Other arrangements of the ignition source are also conceivable.
• the ignition source 34 is configured to ignite the hydrogen gas supplied via a fuel arrangement, as described herein.
• the ignition source 34 is a spark plug.
• a spark plug is a device for delivering electric current from an ignition system to the combustion chamber of a spark-ignition engine to ignite the compressed fuel/air mixture by an electric spark, while containing combustion pressure within the ICE 20.
• the ICE system 10 comprises a first intake manifold 22.
• the first intake manifold 22 is arranged and configured to receive fresh air.
• the fist intake manifold 22 is provided for receiving fresh air.
• the first intake manifold 22 is thus an air intake manifold.
• An air intake manifold is a duct which is arranged and configured to feed intake air to the cylinders, in this example the cylinder 30.
• the first intake manifold 22 is configured to be in fluid communication with an intake port 35 of the cylinder 30.
• the intake port 35 is a first intake port 35.
• the cylinder 30 of the ICE 20 comprises the first intake port 35.
• the first intake port 35 is arranged at a top end 36 of the cylinder 30.
• the first intake port 35 is configured to be in fluid communication with the combustion chamber 32.
• the top end 36 is here an integral part of the cylinder head 30b.
• the flow of combustible gas through the first intake port 35 is here controllable by a controllable intake valve 37.
• the combustible gas is one example of a fluid medium.
• the combustible gas comprises fresh air.
• the combustible gas contains a mix of air and port injected hydrogen gas (the gaseous fuel). More specifically, in one example where the ICE system 10 is a direct injected ICE system, the intake valve 37 is controlled so that only air is supplied through the first intake port 35. In another example, in which the ICE system 10 is a port injected ICE system, the intake valve 37 is controlled so that a mix of air and hydrogen fuel is supplied through the first intake port 35.
• the controllable intake valve 37 is arranged to open and close a fluid passage of the first intake port 35, thus controlling the flow of fluid medium to the combustion chamber 32.
• the cylinder 30 of the ICE 20 comprises an exhaust port 38 arranged distal from the top end 36 of the cylinder 30, such that the first intake port 35 and the exhaust port 38 are located at different positions and separated by the piston top end 33 when the first piston 31 is in its top dead center.
• the exhaust port 38 is configured to exhaust combusted gas from the cylinder 30.
• the exhaust port 38 is arranged distal from the top end 33 of the cylinder 30.
• the intake port 35 and the exhaust port 38 are located at different positions and separated by the top end 33 when the piston 31 is in its TDC.
• distal means that the exhaust port 38 is arranged spaced apart from the top end 33 in a direction Z of the cylinder 30 corresponding to an axial direction of the piston 31.
• the top end 33 is thus considered to be a proximal part of the cylinder 30.
• the piston 31 is arranged in the cylinder 30 for reciprocal movement along a central axis Z A1 , here extending in the direction Z.
• the axial direction of the piston 31 corresponds to the direction Z.
• the central axis Z A1 is thus arranged in parallel to the direction Z.
• the exhaust port 38 is arranged axially distal from the top end 33 of the cylinder 30 in the axial direction of the cylinder 30 and the piston 31, here corresponding to the direction Z.
• the exhaust port 38 is arranged axially distal from the top end 33 of the cylinder 30, allowing the first intake port 35 and the exhaust port 38 to be fluidly separated by the piston 31.
• the exhaust port 38 is arranged at a lower to mid part 39 of the cylinder 30, as shown in Fig. 2 .
• the cylinder liner when the cylinder 30 comprises the cylinder liner, the cylinder liner here also comprises the exhaust port 38 located at a lower to mid part 39 of the cylinder liner.
• the exhaust port 38 is generally arranged distal from the top end 33 of the cylinder 30 and positioned in the cylinder wall 30a of the cylinder liner of the cylinder 30.
• the exhaust port 38 is arranged in fluid communication with an exhaust duct 61.
• the exhaust duct 61 is arranged to transport exhaust gas away from the cylinder 30.
• the cylinder 30 comprises a second intake manifold 86.
• the second intake manifold 86 is configured to be in fluid connection with an exhaust gas recirculation EGR system 80.
• the second intake manifold 86 is considered as an EGR manifold to the ICE 20.
• the second intake manifold 86 is a separate manifold from the first intake manifold 22, and thus fluidly separated from the first intake manifold 22.
• the second intake manifold 86 is configured to be in fluid communication with a second intake port 87.
• the second intake port 87 is arranged at the top end 36 of the cylinder 30.
• the cylinder 30 here comprises the second intake port 87.
• the second intake port 87 is configured to be in fluid communication with the combustion chamber 32.
• the second intake manifold 86 is separate from the first intake manifold 22.
• the second intake manifold 86 is fluidly separated from the first intake manifold 22.
• the second intake manifold 86 may thus also be physically separated from the first intake manifold 22.
• the second intake manifold 86 is separated from the first intake manifold 22 as in Fig. 2 , in which the second intake manifold 86 for EGR is arranged on one side of the ICE 20, and the first intake manifold 22 for the fresh air is arranged on the other side of the ICE 20.
• the flow of gas through the second intake port 87 is controllable by a controllable EGR control valve 88, as shown in Fig. 2 .
• the EGR system 80 comprises an EGR conduit 81.
• the EGR conduit 81 is arranged to connect the exhaust duct 61 to the second intake manifold 86.
• the EGR conduit 81 is arranged to connect the exhaust duct 61 to the second intake manifold 86 so as to permit recirculation of exhaust gas through the cylinder 30 during operation of the ICE 20.
• the EGR conduit 81 is adapted to connect to the exhaust duct 61 at a position 85.
• the position 85 is downstream the exhaust port 38.
• the EGR system 80 comprises a positive displacement device 82 configured to direct EGR gas to the second intake manifold 86.
• a positive displacement device 82 is used to control the flow of EGR gas.
• the device 82 ensures that the EGR flow rate is consistent and can be finely adjusted according to the operating conditions of the ICE.
• the precise control of EGR flow further helps in maintaining the combustion temperature and reducing NOx emissions.
• the positive displacement device 82 is here a positive displacement pump.
• the positive displacement pump 82 is configured to displace gas from an upstream position to a downstream position of the EGR conduit 81 thereof by trapping a fixed amount of exhaust gases and forcing that trapped amount of exhaust gas from the upstream position to the downstream position, which here corresponds from the exhaust duct 61 to the second manifold 86.
• the positive displacement device 82 is a rotary roots type blower having a pair of rotary members 82a, 82b provided with meshing lobes.
• Other configurations of the positive displacement device 82 may also be readily appreciated.
• the positive displacement device 82 is a variable positive displacement device configured to be operated in a variable manner.
• the use of a variable driven positive displacement device allows for a higher flexibility of the EGR conduit 81 forming the EGR system of the ICE system 10.
• the use of a variable driven positive displacement device also contributes to improve the overall function of the ICE system 10.
• Positive displacement devices may generally operate with flow and pressure as independent variables. This means that if pressure increases and speed remains constant, the flow rate is largely unaffected.
• a variable positive displacement device, such as a pump is a device that converts mechanical energy to hydraulic (fluid) energy. The displacement can be varied while the pump is running.
• the positive displacement device may be driven variably for the high flexibility and improved functionality of the ICE system.
• the positive displacement device 82 may be electrically driven, hydraulically driven, etc.
• the positive displacement device 82 is controllable in response to an operational parameter of the ICE system 10.
• the operational parameter of the ICE system 10 is any one of engine load, engine speed and exhaust temperature.
• Such operating parameters can be measured in the ICE system 10 through one or more sensors (not illustrated), such as by a Lambda sensor in the exhaust conduit and/or by a knock sensor in the ICE 20. The readings of the sensors can be transferred to the controller 90 for further processing and control of the positive displacement device 82.
• the EGR system 80 comprises an EGR cooler 89 for regulating the temperature of the EGR gas.
• the temperature of the EGR gas can be reduced to a suitable temperature for the operation of the ICE 20.
• the temperature is typically regulated to a level that allows for increased cylinder filling, i.e. filling the combustion chamber with EGR.
• the arrangement of the EGR cooler 89 also contributes to dehumidify the EGR gas.
• Using an EGR cooler 89 in an ICE system 10 for a hydrogen ICE is useful because the exhaust gases contain water as a by-product.
• the EGR cooler 89 may be a conventional heat exchanger, such as an air-to-air radiator. Other examples may be a flat plate heat exchanger or a tube heat exchanger.
• the ICE system 10 is configured to operate at a target lambda value of about one.
• a lambda value is indicative of a ratio between an amount of air and an amount of fuel in a combustion chamber of an engine.
• the target lambda 1 thus refers to a target air-fuel equivalence ratio of 1 and may be determined by the ratio of actual air-fuel ratio (mass of air to fuel) to stoichiometric air-fuel ratio, for a given mixture.
• the target lambda is essentially 1.
• the ICE system 10 is configured to operate at a target lambda value of about one by controlling the positive displacement device 82 in response to the operational parameter of the ICE system 10.
• the ICE system 10 is configured to control the fuel injection rate and, in some cases, the air intake from the first intake manifold 22.
• the ICE system 10 is capable of maintaining the air-fuel mixture at or near the stoichiometric ratio. Adjusting the air intake helps the ICE system 10 to maintain the desired air-fuel ratio.
• the air intake amount typically equals mainly the torque or power for the engine when operating at lambda 1. Lambda 1 is maintained e.g. by the fuel dosing/ metering.
• the ICE system 10 may further use one or more oxygen sensors, also known as lambda sensors.
• the lambda sensors are located in the exhaust system, such as in the exhaust duct 61 and configured to provide real-time feedback on the oxygen content of the exhaust gases.
• the controllable EGR control valve 88 can be provided and designed in several different ways.
• the controllable EGR control valve 88 is a conventional poppet valve.
• the poppet valve is disposed in the cylinder head 30b.
• the controllable EGR control valve 88 is arranged at the end of the second intake port 87 (towards the cylinder 30), as may be gleaned from Fig. 2 .
• controllable EGR control valve 88 can also be controlled in several different ways.
• controllable EGR control valve 88 is here configured to be controllable to purge the cylinder 30 from combusted gas after an ICE work stroke by supplying EGR gas to the combustion chamber 32 via the second intake port 87.
• controllable EGR control valve 88 is configured to be controllable by an actuator 97 of a controllable valve actuation assembly 63.
• the ICE system 10 comprises a controllable valve actuation assembly 63 for actuating the controllable EGR control valve 88.
• the actuator 97 is an integral part of the controllable valve actuation assembly 63.
• the controllable valve actuation assembly 63 is e.g. a camshaft-driven valve actuation system, which comprises a camshaft.
• controllable valve actuation assembly 63 is here arranged and configured to actuate both the controllable EGR control valve 88 and the controllable intake valve 37.
• the controllable valve actuation assembly 63 is adapted to actuate the controllable EGR control valve 88 and controllable intake valves 37 in accordance with one or more lift modes during the two-stroke operation of the ICE 20.
• controllable EGR control valve 88 and the controllable intake valve 37 may typically be actuated by a common camshaft having two spaced apart actuators (cam lobes).
• controllable EGR control valve 88 is configured to be controllable by an actuator 97 of the controllable valve actuation assembly 63 in the form of a variable valve actuation system.
• a variable valve actuation system is a camless system, such as a flow control valve assembly.
• a flow control valve assembly typically comprises an actuator in the form of a hydraulic, electric, and/or a pneumatic actuator.
• the controllable valve actuation assembly 63 is typically configured to be controlled by a control system, such as the controller 90 (as illustrated in Fig. 1 ).
• the second intake port 87 is typically a through hole in the cylinder head 30b, as illustrated in Fig. 2 .
• the second intake port 87 can be designed in several different ways.
• the second intake port 87 is a swirl intake port configured to create a swirling motion of the fluid medium.
• Fuel injection of hydrogen gas may be provided either directly into the combustion chamber 32 or in the form of so-called port fuel injection.
• the cylinder 30 may optionally comprise a fuel injector arrangement for injecting fuel.
• the fuel injector arrangement is arranged in the combustion chamber 32.
• the ICE system 10 may alternatively, or in addition, be configured for port fuel injection, which means that the fuel injector arrangement is typically arranged upstream the intake port 35. Port fuel injection is further described in relation to Fig. 3 .
• Fig. 3 depicts further details of the ICE system 10, in which the ICE system 10 and the ICE 20 of Fig. 1 and 2 are illustrated with a set of two cylinders.
• the ICE 20 comprises a set of two cylinders.
• the at least one cylinder described in relation to Fig. 2 is denoted as the first cylinder 30.
• the other features described in relation to Fig. 2 are in Fig. 3 denoted with the term "first”.
• the piston in Fig. 2 is here a reciprocating first piston 31, or simply the first piston 30, the cylinder wall is here a first cylinder wall 30a, the cylinder head is here a first cylinder head 30b, etc.
• the ICE 20 comprises the first cylinder 30 and a second cylinder 40.
• the first cylinder 30 comprises a first cylinder wall 30a and a first cylinder head 30b.
• the first cylinder wall 30a may be part of a cylinder liner.
• the second cylinder 40 comprises a second cylinder wall 40a and a second cylinder head 40b.
• the second cylinder wall may be part of a corresponding cylinder liner.
• the first and second cylinders 30, 40 are here a pair of first and second cylinders 30, 40.
• the first and second cylinders 30, 40 are here a pair of neighboring first and second cylinders 30, 40.
• the term "neighboring" generally means that the cylinders are arranged next to each other, i.e. adjacent to each other within the ICE system, so as to allow for forming a pair of cylinders operating according to the two-stroke operation.
• the first and second cylinders 30, 40 are arranged next to each other in the ICE 20. This may have a positive impact on the volumetric efficiency of the ICE system 10.
• the first and second cylinders 30, 40 may in some ICE systems be arranged slightly distanced from each other as long as the cylinders work as a pair of cylinders, i.e. the cylinders are connected to the same crank shaft and separated with a 180 crank angle degrees, as further described herein.
• the ICE 20 may comprise any even number of cylinders.
• the ICE 20 may comprise four, six, or eight cylinders.
• the description herein is for an ICE system 10 having a pair of cylinders 30, 40.
• the ICE system 10 further comprises the crank shaft 27, a set of connecting rods, 28, 29 and a crankcase 65.
• the crankcase 65 is configured to accommodate the crank shaft 27 and the connecting rods 28, 29.
• Each one of the connecting rods 28, 29 is operatively connected to a corresponding piston, as further described below.
• the ICE system 10 may also comprise an oil sump 62 and a splash plate 68 for the oil. These components are conventional parts of an ICE, and not further described herein.
• the first cylinder 30 is configured to accommodate the reciprocating first piston 31.
• the reciprocating first piston 31 is operable between a bottom dead center, BDC, and a top dead center, TDC. More specifically, the first piston 31 is arranged to reciprocate in the first cylinder 30 between the BDC and the TDC.
• the first piston 31 is in the TDC position at -360°, 0° and 360° CAD.
• the first piston 31 is via the connection rod 28 connected to the crank shaft 27, which is in line with a conventional ICE.
• the first piston 31 may generally comprise a suitable number of piston rings.
• the first piston 31 comprises one or more compression rings and oil control rings. The number of piston rings and type of piston rings are selected based on the fuel of the ICE system 10.
• the piston rings are arranged at a top end 33 of the first piston 31.
• the reciprocating first piston 31 further at least partly defines the first combustion chamber 32 with the top end 33 of the first piston 31.
• the combustion chamber 32 is arranged at the end portion, i.e. the first cylinder head 30b, of the first cylinder 30 so that an upper surface of the top end 33 defines a lower side of the first combustion chamber 32.
• the first cylinder 30 further comprises the ignition source 34.
• the ignition source 34 is arranged in the first combustion chamber 32.
• the ignition source 34 is arranged in the first cylinder 30 and at a location facing the combustion chamber 32.
• the ignition source 34 is arranged at an upper end of the cylinder 30, as illustrated in Fig. 3 .
• the ignition source 34 is arranged at the cylinder head 30b of the first cylinder 30.
• the first cylinder 30 of the ICE 20 comprises the least one intake port 35 arranged at the top end 36 of the first cylinder 30 and in fluid communication with the combustion chamber 32.
• the top end 36 is here an integral part of the cylinder head 30b.
• the flow of combustible gas through the first intake port 35 is controllable by the controllable intake valve 37.
• the combustible gas may generally contain a mix of air and port injected hydrogen gas (the gaseous fuel).
• the controllable intake valve 37 is arranged to open and close a fluid passage of the intake port 35, thus controlling the flow of fluid to the combustion chamber 32.
• the first cylinder 30 of the ICE 20 comprises the exhaust port 38 arranged distal from the top end 36 of the first cylinder 30, such that the first intake port 35 and the exhaust port 38 are located at different positions and separated by the piston top end 33 when the first piston 31 is in its top dead center. More specifically, as illustrated in Fig.
• the first cylinder 30 comprises a first exhaust port 38.
• the first exhaust port 38 is configured to exhaust combusted gas from the first cylinder 30.
• the first exhaust port 38 is arranged distal from the top end 33 of the first cylinder 30.
• the intake port 35 and the exhaust port 38 are located at different positions and separated by the top end 33 when the first piston 31 is in its TDC.
• distal means that the first exhaust port 38 is arranged spaced apart from the top end 33 in a direction Z of the first cylinder 30 corresponding to an axial direction of the first piston 31.
• the top end 33 is thus considered to be a proximal part of the first cylinder 30.
• the first piston 31 is arranged in the first cylinder 30 for reciprocal movement along a central axis Z A1 , here extending in the direction Z.
• the axial direction of the first piston 31 corresponds to the direction Z.
• the central axis Z A1 is thus arranged in parallel to the direction Z.
• the first exhaust port 38 is arranged axially distal from the top end 33 of the first cylinder 30 in the axial direction of the first cylinder 30 and the first piston 31, here corresponding to the direction Z.
• the exhaust port 38 is arranged at a lower to mid part 39 of the first cylinder 30.
• the cylinder liner when the first cylinder 30 comprises the first cylinder liner 30a, the cylinder liner here also comprises the first exhaust port 38 located at a lower to mid part 39 of the cylinder liner.
• the first exhaust port 38 is typically arranged distal from the top end 33 of the first cylinder 30 and positioned in the cylinder wall 30a of the cylinder liner of the first cylinder 30.
• the second cylinder 40 is configured to accommodate a reciprocating second piston 41.
• the reciprocating second piston 41 is operable between a bottom dead center, BDC, and a top dead center, TDC. More specifically, the second piston 41 is arranged to reciprocate in the second cylinder 40 between the BDC and the TDC.
• the second piston 41 is in the TDC position at -360°, 0° and 360° CAD.
• the second piston 41 is via a connection rod 29 connected to the crank shaft 27, which is in line with a conventional ICE.
• the second piston 41 typically comprises a suitable number of piston rings.
• the second piston 41 comprises one or more compression rings and oil control rings.
• the number of piston rings and type of piston rings are selected based on the fuel of the ICE system 10.
• the piston rings are arranged at a top end 43 of the second piston 41.
• the reciprocating second piston 41 further at least partly defines a second combustion chamber 42 with a top end 43 of the second piston 41.
• the combustion chamber 42 is arranged at end portion, i.e. the second cylinder head 40b, of the second cylinder 40 so that an upper surface of the top end 43 defines a lower side of the second combustion chamber 42.
• Each one of the piston top ends may have a flat top or the piston top ends may be slightly dished so as to avoid hotspots.
• the second cylinder 40 further comprises a corresponding ignition source 44 arranged in the second combustion chamber 42.
• the ignition source 44 is arranged in the second cylinder 40 and at a location facing the combustion chamber 42.
• the ignition source 44 is arranged at an upper end of the combustion cylinder 40, as illustrated in Fig.
• the ignition source 44 is arranged at the cylinder head 40b of the second cylinder 40. Other arrangements of the ignition source are also conceivable.
• Each one of the ignition sources 34, 44 is here a spark plug.
• the ignition source may also be a glow plug.
• each cylinder 30, 40 there is a corresponding spark plug 34, 44 arranged to ignite a mix of fuel and oxygen in the cylinder.
• the hydrogen fuel is generally compressed to a certain level.
• the compressed air-fuel mixture is thus ignited by the spark plug.
• the second cylinder 40 of the ICE 20 comprises at least one corresponding intake port 45 arranged at a top end 46 of the second cylinder 40 and in fluid communication with the second combustion chamber 42.
• the top end 46 is here an integral part of the cylinder head 40b.
• the flow of combustible gas through the at least one corresponding intake port 45 is controllable by a corresponding controllable intake valve 47.
• the combustible gas may generally contain a mix of air and port injected hydrogen gas (the gaseous fuel).
• the controllable intake valve 47 is arranged to open and close a fluid passage of the intake port 45, thus controlling the flow of fluid to the combustion chamber 42.
• the second cylinder 40 of the ICE 20 comprises a corresponding exhaust port 48 arranged distal from the top end 46 of the second cylinder 40, such that the at least one corresponding intake port 45 and the corresponding exhaust port 48 are located at different positions and separated by the piston top end 43 when the corresponding second piston 41 is in its top dead center.
• the corresponding exhaust port 48 is configured to exhaust combusted gas from the second cylinder 40.
• the corresponding exhaust port 48 is arranged distal from the top end 43 of the second cylinder 40.
• the corresponding intake port 45 and the corresponding exhaust port 48 are located at different positions and separated by the top end 43 when the second piston 41 is in its TDC.
• distal means that the corresponding exhaust port 48 is arranged spaced apart from the top end 43 in the direction Z of the second cylinder 40 corresponding to an axial direction of the second piston 41.
• the top end 43 is thus considered to be a proximal part of the second cylinder 40.
• the second piston 41 is arranged in the second cylinder 40 for reciprocal movement along a central axis Z A2 , here extending in the direction Z.
• the axial direction of the second piston 41 corresponds to the direction Z.
• the central axis Z A2 is thus arranged in parallel to the direction Z.
• the corresponding exhaust port 48 is arranged axially distal from the top end 43 of the second cylinder 40 in the axial direction of the second cylinder 40 and the second piston 41, here corresponding to the direction Z.
• the corresponding exhaust port is arranged at a lower to mid part 49 of the second cylinder 40.
• the exhaust port is arranged at a lower to mid part of the second cylinder 40 as seen along the central axis Z A2 .
• first central axis Z A1 of the first piston 31 is arranged parallel to the second central axis Z A2 of the second piston 41.
• the pistons 31, 41 may also be arranged in a slightly different configuration where the first central axis ZA1 of the first piston 31 is arranged non-parallel to the second central axis Z A2 of the second piston 41, at least as long as the first and second cylinders are arranged separated from each other with a crank angle of 180 degrees.
• the cylinder liner comprises the corresponding exhaust port located at a lower to mid part of the cylinder liner.
• the corresponding exhaust port is typically arranged distal from the top end 43 of the second cylinder 40 and positioned in the cylinder wall 40a of the cylinder liner of the second cylinder 40.
• the pair of neighboring first and second cylinders 30, 40 are arranged separated from each other with a crank angle of 180 degrees (180 CAD).
• 180 CAD 180 degrees
• the cylinders 20, 30 are separated from each other so to provide a 180 degrees combustion phasing separation.
• the cylinders 30, 40 can be arranged in the ICE system 10 to provide a 180 degrees cycle separation irrespectively of the ICE and cylinder arrangement/configuration.
• the respective intake ports 35, 45 and exhaust ports are in each cylinder 30, 40 located at different positions and separated by the respective piston top end 33, 43 when the respective piston is in its TDC. Accordingly, by arranging the respective intake port 35, 45 and exhaust port 38 of the cylinders 30, 40 at different positions along the direction Z (i.e. along the axial directions of the pistons and cylinders), the corresponding piston will provide for a blocking effect between the intake and exhaust ports when the corresponding piston is in its TDC, so that the hot part of the cylinder (exhaust port and cylinder wall/liner) will be entirely separated from the combustible gas (air).
• the blocking effect is at least schematically illustrated in Fig. 3 .
• the configuration of the intake and exhaust ports enables a length-scavenging ICE system that separates the hot exhaust end of each cylinder from the cold intake end where the combustibles are present. Therefore the knock risk may be reduced during operation of the ICE system 10.
• this also allows for a reversed scavenging of the corresponding combustion chamber with the controllable intake valves in the cylinder head and the exhaust ports at the cylinder wall/liner (e.g. in the lower part of cylinder wall). In other words, there are no exhaust valves in the cylinder head as compared to more conventional ICE systems.
• the ICE system 10 is configured to provide a forced induction in the top of the cylinders, an ignition source for igniting the hydrogen fuel in each combustion chamber 32, 42, while further being configured to expel the exhaust gases through respective exhaust port 38, 48 in the lower to mid parts of the respective cylinder, e.g. lower parts of the walls 30a, 40a of the cylinder liners.
• the second cylinder comprises a corresponding second intake port 87 having a corresponding controllable EGR control valve 88.
• the first cylinder 30 is provided with the second intake port 87 having the controllable EGR control valve 88 and the second cylinder 40 is provided with a corresponding second intake port 87 having a corresponding controllable EGR control valve 88.
• the corresponding second intake port 87 is arranged at the top end 46 of the second cylinder 40.
• the corresponding second intake port 87 is arranged in the cylinder head 40b.
• the corresponding second intake port 87 typically extends through the cylinder head 40b, as illustrated in Fig. 3 .
• the corresponding second intake port 87 is configured to be in fluid communication with the combustion chamber 42.
• the corresponding controllable EGR control valve 88 is disposed in the corresponding second intake port 87.
• the corresponding controllable EGR control valve 88 is configured to control the flow of EGR gas to the second cylinder 40 by controlling the flow of EGR gas through the corresponding second intake port 87 in similar manner as described in relation to the controllable EGR control valve 88 of the first cylinder 30.
• the corresponding second intake port 88 is fluidly connected to the EGR conduit 81.
• the EGR system 80 may thus be fluidly connected to a set of second intake ports 87 and a set of controllable EGR control valves 88.
• the corresponding EGR control valve 88 is controllable to purge the second cylinder 40 from combusted gas after an ICE work stroke by supplying EGR gas to the combustion chamber 40 via the corresponding second intake port 87.
• the EGR system 80 here optionally comprises a water condenser and extraction system 83 for condensing exhaust gases and extracting water from the exhaust gases.
• the water condenser and extraction system 83 is disposed in the EGR conduit 81 downstream of the EGR cooler 89.
• the water condenser and extraction system 83 functions as condense separation unit.
• the water condenser and extraction system 83 is configured to reduce flow velocity.
• the water condenser and extraction system 83 comprises a water extraction device for separating water from the exhaust gases.
• the water condenser and extraction system 83 typically defines a volume for reducing the flow of exhaust gases.
• the water condenser and extraction system 83 may comprise a conventional heat exchanger, such as a surface condenser, e.g. a water-cooled shell and tube heat exchanger installed to condense exhaust gases.
• the water condenser and extraction system 83 may also comprise a separate water extraction device (not illustrated), which is configured to extract water from the exhaust gases. separate exhaust gases and coolant water.
• the water condenser and extraction system 83 is typically provided with an outlet 83a for the extracted water.
• the outlet 83a can be fluidly connected to the cylinder(s) 30, 40 of the ICE 20 so as to permit water injection into the combustion chamber(s) 32, 42.
• the water condenser and extraction system 83 is fluidly connected to a water injector system (not illustrated) configured to inject water into the combustion chamber(s).
• the water injection system can be arranged and configured to inject water in the intake port(s), directly into the cylinder, or to the first intake manifold 22. As such, the condensed water from the exhaust gases can be used for water injection.
• the water condenser and extraction system 83 is provided in the form of a volume where the exhaust gas flow velocity is reduced. Such volume can be provided with or without the water extractor.
• the water extracting function can be achieved through e.g. centrifugal forces, droplet agglomeration on net surfaces etc.
• the combination of the EGR cooler 89 and the water condenser and extraction system 83 allows for operating the EGR cooler for condensation removal purposes where the EGR cooler is controllable to provide a condensation trap.
• the first intake manifold 22 here comprises a corresponding positive displacement device 23, as illustrated in Fig. 3 .
• the corresponding positive displacement device 23 is configured to receive and feed intake air 51 to the at least one pair of neighboring cylinders 30, 40.
• the first intake manifold 22 comprises an intake tract 24 and a plenum 25.
• the air intake tract 24 is arranged upstream the corresponding positive displacement device 23.
• the plenum 25 is arranged downstream the corresponding positive displacement device 23.
• the corresponding positive displacement device 23 is also arranged in the first intake manifold 22 to separate the upstream intake tract 24 from the downstream plenum 25 of the first intake manifold 22.
• the plenum 25 may in some examples be an integral part of the cylinder heads of the cylinders.
• at least parts of the first intake manifold 22 may be integral parts of the cylinder heads of the cylinders.
• the corresponding positive displacement device 23 is configured to fluidly seal against back flow from the combustion chamber(s) 32, 42. Furthermore, the corresponding positive displacement device 23 is configured to exhaust its (complete) internal displacement for each revolution.
• the corresponding positive displacement device 23 is here a positive displacement pump.
• the positive displacement pump is configured to displace gas from an upstream position to a downstream position of the first intake manifold 22 thereof by trapping a fixed amount of air and forcing that trapped amount of air from the upstream position to the downstream position.
• the corresponding positive displacement device 23 is a rotary roots type blower having a pair of rotary members 23a, 23b provided with meshing lobes.
• Other configurations of the corresponding positive displacement device may also be readily appreciated.
• the corresponding positive displacement device 23 is here also a variable positive displacement device configured to be operated in a variable manner.
• the use of a variable driven positive displacement device allows for a higher flexibility of the air intake manifold forming the air intake system of the ICE system 10.
• the use of a variable driven positive displacement device also contributes to improve the overall function of the ICE system 10.
• Positive displacement devices may generally operate with flow and pressure as independent variables. This means that if pressure increases and speed remains constant, the flow rate is largely unaffected.
• a variable positive displacement device, such as a pump is a device that converts mechanical energy to hydraulic (fluid) energy. The displacement can be varied while the pump is running.
• the positive displacement device may be driven variably for the high flexibility and improved functionality of the ICE system.
• the positive displacement device 23 may be electrically driven, hydraulically driven, etc.
• An electrified positive displacement device may also improve turbo transients by boosting with scavenging that may also drive the turbine in the turbo.
• Such configuration of the ICE system may allow for reduced pressure before the displacement pump and/or after the turbo compressor reducing compressor work instantly.
• the upstream intake tract 24 is here an integral part of the first intake manifold 22.
• the upstream intake tract 24 is by way of example provided in the form of a cylindrical shaped housing having an inner volume.
• the plenum 25 is also generally an integral part of the first intake manifold 22.
• the downstream plenum 25 is in fluid communication with each one of the first and second cylinders 30, 40.
• the downstream plenum 25 is in fluid communication with each one of the first and second cylinders 30, 40 via respective intake ports 35, 45.
• the downstream plenum 25 is provided in the form of a so-called Siamese-shaped design.
• Siamese-shaped design has a first inlet conduit 25a and a set of two outlet conduits 25b, 25c, as schematically illustrated in Fig. 3 .
• the diameter and length of the inlet and outlet conduits may vary depending on the type of ICE system 10, and the plenum 25 in Fig. 3 is only schematically illustrated.
• the plenum 25 comprises an air inlet 25d in fluid communication with the corresponding positive displacement device 23 and a plurality of outlets 25e, 25f configured to be in fluid communication with the intake ports 35, 45 of the first and second cylinders 30, 40, respectively.
• the first inlet conduit 25a has the air inlet and the outlet conduits 25b, 25c have the corresponding outlets. Accordingly, the plenum 25 is defined by the conduit arrangement between the intake ports 35, 45 of the first and second cylinders 30, 40 and the corresponding positive displacement device 23, as depicted in e.g. Fig. 3 .
• the plenum 25 may also be provided in other ways, e.g. by a single large inner volume defined by a common conduit.
• the internal volume of the plenum should generally be selected to provide an efficient backfire protection and may thus benefit from being minimized in volume in view of the other volumes of the other components.
• the plenum 25 in combination with the arrangement and configuration of the positive displacement device 23 provides for an improved air supply system for supplying air to the cylinders 30, 40.
• the positive displacement device 23 provides for an essentially fluid-tight seal in the air intake manifold 22, it will be a continuous flow of air through the positive displacement device 23 thanks to the configuration of the cylinders 30, 40 with a 180 CAD separation, since the pair of cylinders 30, 40 interact with respect to the intake event.
• the positive displacement device 25 is arranged to eliminate, or at least reduce, the risk of having pressure pulses transferred backwards from the combustion chambers 30, 40 to the upstream intake tract 24 of the air intake manifold 22.
• the intake ports 35, 45 are mechanically isolated from the intake tract 24.
• the proposed ICE system provides for suppressing the tendency for knock and/or self-ignition of the fuel, such as a gaseous fuel, e.g. hydrogen-based fuel.
• a gaseous fuel e.g. hydrogen-based fuel.
• This is e.g. provided by the combination of having a separate intake plenum 23 for each pair of cylinders 30, 40 with the 180 degrees combustion phasing separation, and where the intake manifold 22 has a close coupled positive displacement device 23 for each pair of cylinders 30, 40.
• the positive displacement device 25 close to the cylinders, the internal volume of the plenum 25 can be minimized, thus providing for an even more efficient backfire protection.
• the ICE system 10 in Fig. 3 comprises a fuel injector arrangement 26.
• the fuel injector arrangement 26 is arranged in the plenum 25 of the air intake manifold 22 so as to provide a fuel injection upstream the intake ports 35, 45 of the cylinders 30, 40. In this manner, there is provided an improved injection of fuel into the combustion chambers 32, 42 of the ICE 20.
• the fuel injector arrangement 26 comprises at least one fuel injector configured inject fuel.
• the fuel injector arrangement 26 comprises a set of two fuel injector, 26a, 26b.
• the outlet conduit 25b comprises a first fuel injector 26a and the outlet conduit 25c comprises the second fuel injector 26b.
• the ICE system 10 is configured to provide port injection of the gaseous fuel 50 upstream respective intake port 35, 45.
• the use of a port injection allows for providing a homogenous mixture which enables an improved knock and auto-ignition control and contribute to reduce the emissions.
• the fuel injector arrangement 26 is operable / controllable in response to a fuel injection event such that fuel injection is injected to one or more of the corresponding intake ports 35, 45 such that pressure pulses are generated in the plenum 25 and subsequently travel into the corresponding combustion chambers 32, 42.
• a fuel injection event such that fuel injection is injected to one or more of the corresponding intake ports 35, 45 such that pressure pulses are generated in the plenum 25 and subsequently travel into the corresponding combustion chambers 32, 42.
• the ICE system 10 is configured to provide a scavenging effect by the injection timing in the respective intake port 35, 45.
• the fuel injector arrangement 26 is operable / controllable to provide a sequential injection of fuel to the cylinders 30, 40 so as to allow for an active cylinder scavenging during a latter part of a corresponding intake stroke of a corresponding cylinder of the cylinders 30, 40.
• a sequential injection enables active cylinder scavenging (emptying of exhaust) during latter part of the intake stroke and creates a final pressure pulse (from the injected fuel) that increases the trapped mass in the cylinder after any exhaust port and intake valve closures. This may also contribute to a fuel-free plenum and/or intake port after the intake valve closure. Further, the generated pressure pulse increases the scavenging effect.
• the sequential injection can be tuned for different speeds and valve timings.
• the pressure pulse will also travel backwards in the downstream plenum 25. For instance, the pressure pulse will be reflected in the sister cylinder intake valve that is closed. Thereafter, the pressure pulse travels back to the still open intake valve and enters the cylinder with the open valve and complete the cylinder filling, thus also contributing to the complete trapped mass.
• the fuel injectors 26a, 26b of the fuel injector arrangement 26 may be arranged in each one of the combustion chambers of the cylinders.
• the ICE system 10 in Fig. 3 may be provided with a number of two intake valves 37 for the first cylinder 30 and a number of two controllable intake valves 47 for the second cylinder 40.
• each one of the cylinder heads 30b, 40b comprises a number of at least two controllable intake valves.
• each one of the cylinder heads 30b, 40b of the first and second cylinders 30, 40 may have a plurality of controllable intake valves.
• controllable intake valves 37, 47 are configured to provide variable valve actuation.
• the variable valve actuation can be provided by a hydraulic system, electronic system or pneumatic system.
• the controllable intake valves 37, 47 may also be conventional controllable intake valves, such as a camshaft-based system, as is commonly used in diesel ICE systems.
• the controllable intake valves are conventional camshaft actuated valves.
• Such camshaft actuated valves may also include variable valve actuation depending on arrangement and configuration of the valves.
• controllable valve actuation assembly 63 is arranged for actuating the controllable EGR control valves 88, the inlet control valve 37 and the corresponding inlet control valve 47.
• the valve actuation assembly 63 is adapted to actuate the controllable EGR control valves 88 and the inlet control valves 37, 47 in accordance with one or more lift modes during the combustion cycle of the ICE system 10.
• each one of the exhaust ports 38, 48 is arranged in fluid communication with the exhaust duct 61 arranged to transport exhaust gas away from each one of the cylinders.
• the ICE system 10 comprises a turbocharger arrangement 70.
• the turbocharger arrangement 70 comprises the turbocharger turbine 71 operatively connected to a turbocharger compressor 72, wherein the turbocharger compressor 72 is arranged in an air intake conduit 73 in fluid communication with the first intake manifold 22 (air intake manifold).
• the turbocharger turbine 71 is arranged in the exhaust duct 61 so as to drive the turbocharger compressor 72.
• the turbine 71 is configured to convert engine exhaust gas into mechanical energy to drive the compressor 72.
• the turbocharger turbine 71 may be a conventional turbine for an ICE system 10. Alternatively, the turbocharger turbine 71 may be a variable geometry turbine in fluid communication with the cylinders.
• the EGR conduit 81 is adapted to connect to the exhaust duct 61 at the position 85, which is upstream of the turbocharger turbine 71.
• the ICE system 10 may also comprise an air cooler 67, such as charge air cooler (CAC).
• CAC charge air cooler
• the CAC 67 is arranged in the air intake conduit 73. More specifically, the CAC 67 is arranged in the air intake conduit 73 between the turbocharger compressor 72 and the air intake manifold 22, as seen in a direction of flow from the compressor 72 to the air intake manifold 22.
• first intake manifold 22 of Fig. 3 may have its own inlet 75 for receiving fresh air from the outside and/or be configured to receive air from the air intake conduit 73.
• the controller 90 is typically configured to collectively control the positive displacement device 23 and the intake valves 37, 47 so as to control flow of gas to the respective combustion chambers 32, 42, and further configured to control the controllable EGE control valve 88 to provide EGR to the cylinder(s), as described herein.
• the controller 90 is also configured to terminate fuel injection during an intake phase and before an intake valve closure, whereby the remaining part of the intake phase comprises emptying the plenum 25 of fuel and subsequently introducing fresh air to the plenum 25 by operating the corresponding positive displacement device 23.
• each one of the first and second cylinders 30, 40 has three primary events. These events are compression event, combustion and work event, and exhaust and intake event.
• the compression event occurs when a corresponding piston is at an upper half of the corresponding cylinder when it travels from BDC to TDC.
• the combustion and work event occurs when a corresponding piston is at an upper half of the corresponding cylinder when it travels from TDC to BDC.
• the exhaust and intake event generally occurs when a corresponding piston is at a lower half of the corresponding cylinder.
• the exhaust and intake event occur when a corresponding piston is at a lower half of the cylinder and is travelling towards its BDC, across its BDC and/or when the corresponding piston is at a lower half of the cylinder and is travelling towards its TDC.
• the exhaust and intake event may occur in different regions of the cylinders, and can be slightly divided, but the exhaust and intake event will generally occur at the same time.
• the ICE system provides the scavenging effect, i.e. fresh intake gas pushes the residual exhaust out the exhaust port.
• the piston 31, 41 of one of the cylinders 30, 40 may generally perform the compression stroke / compression phase (or event) during about 270 - 0 CAD, followed by the combustion and work phase (event) during 0-90 CAD at an upper half of the corresponding cylinder when the piston travels from TDC to BDC, while the other piston of the other cylinder performs the exhaust and intake phase (event) at a lower half of the other cylinder during 90 to 270 CAD. It may also be noted that there is generally an overlap between the end of the combustion and work phase (event) and the start of the exhaust and intake phase (event).
• controllable intake valve 37 of the first cylinder 30 is operable in correlation with the movement of the first piston 31 and the controllable intake valve 47 of the second cylinder 40 is operable in correlation with the movement of the second piston 41.
• the fluid communication between the respective combustion chambers 32, 42 and the plenum 25 is selectively open and closed during a crank shaft revolution of the ICE 20.
• such configuration of the ICE system 10 in combination with the corresponding positive displacement device 23 in the air intake manifold 22 allows for reducing risk of backfire.
• control valve actuation assembly 63 may comprise an electric actuator (not shown) adapted to actuate the inlet control valve(s) in at least two lift modes, i.e. between an open mode and a closed mode.
• the cylinders 30, 40 are separated from each other with a crank angle of 180 degrees.
• Such arrangement and configuration of the ICE system 10 allows for 180 degrees combustion phasing separation. Due to the arrangement of the first and second cylinders 30, 40 being arranged separated from each other with a crank angle of 180 degrees, the ICE system 10 is configured to operate the intake valves 37, 47 of the first and second cylinders 30, 40 such that the intake valves 37, 47 of the cylinders 30, 40 are completely closed when the respective piston is halfway up in the cylinder, which may further reduce the risk of a backfire.
• the injected hydrogen fuel will expand and create a pulse in the intake ports and plenum. This pulse will propagate and add to the scavenging effect and also increase the pressure in the cylinder.
• the pulse is limited from travelling backwards in the air intake manifold (air intake system) by the corresponding positive displacement device 23 acting like a check valve and also momentarily adding boost pressure during the pulse.
• Fig. 4 is another example of the ICE system 10.
• the ICE system 10 here comprises the features and components of the ICE system 10 as described in relation to Figs. 2 and 3 .
• the ICE system 10 of Fig. 4 differs from that shown in Figs. 2 and 3 in that the cylinder 30 further comprises an evacuation port 95.
• the evacuation port 95 is arranged at the top end 36 of the cylinder 30.
• the evacuation port 95 is arranged in the cylinder head 30b.
• the evacuation port 95 typically extends through the cylinder head 30b, as illustrated in Fig. 2 .
• the evacuation port 95 is configured to be in fluid communication with the combustion chamber 32.
• the ICE 20 further comprises a controllable evacuation valve 96 for providing an engine braking operation.
• the cylinder 30 comprises the controllable evacuation valve 96.
• the controllable evacuation valve 96 is disposed in the evacuation port 95.
• the controllable evacuation valve 96 is configured to provide an engine braking operation by controlling the flow of fluid medium through the evacuation port 95. More specifically, the controllable evacuation valve 96 is configured to provide engine braking by permitting the fluid medium, such as compressed air, contained in the combustion chamber 32 to discharge from the combustion chamber 32 through the evacuation port 95.
• controllable evacuation valves 96 configured to permit evacuation of fluid medium from the combustion chamber 32, it becomes possible to provide enhanced engine braking efficiency for two-stroke ICE systems.
• engine braking typically refers to an operation of the engine when the retarding forces within the engine are used to slow a vehicle down.
• the controllable evacuation valve is controlled to an open state, or at least a partly open state, thereby releasing compressed fluid medium trapped in the cylinder via the evacuation port, and slowing down the vehicle.
• controllable evacuation valve 96 is controllable in cooperation with the movement of the piston 31 such that the controllable evacuation valve 96 permits evacuation of fluid medium, such as compressed air, from the combustion chamber 32 via the evacuation port 95 during a compression stroke.
• controllable evacuation valve 96 While the controllable evacuation valve 96 is typically controlled to an open state during the compression stroke, the controllable evacuation valve 96 can in other operating situations for other ICE system be controlled to permit evacuation of fluid medium from the combustion chamber 32 via the evacuation port 95 just after the completion of the compression stroke. Thus, the evacuation of fluid medium from the combustion chamber 32 via the evacuation port 95 may occur at various positions of the piston 31, such as at the end of the compression stroke, or just after the compression stroke.
• the evacuation of fluid medium, such as compressed air, from the combustion chamber 32 via the evacuation port 95 may typically occurs before the intake valve 37 opens.
• the evacuation of compressed air is performed at TDC, before TDC, or slightly after the TDC.
• the evacuation of compressed air can occur adjacent the TDC, such as within a crank angle of 10 degrees after TDC.
• engine braking can be further explained by the following piston movements within the cylinder 30.
• the piston 31 travels up in the combustion chamber 32 (typically referring to the cylinder bore defined by the cylinder liner), air is compressed and provides the main resistance in the engine braking operation.
• the controllable evacuation valve 96 is typically opened so as to permit the compressed air to be evacuated via the evacuation port 95.
• the piston 31 travels down to BDC and starts a new intake cycle, compresses air and thereafter permit the air out again from the evacuation port 95.
• the actuator 97 is deactivated, which means that the controllable evacuation valve 96 is not opening, and the ICE 20 operates in its propulsion mode.
• the camshaft for the engine brake is still rotating but since the actuator 97 is deactivated the camshaft rotates freely, without moving the controllable evacuation valve 96.
• controllable evacuation valve 96 can also be controlled in other ways.
• controllable evacuation valve 96 is controllable in cooperation with the movement of the piston 31 such that the controllable evacuation valve 96 skips evacuation of fluid medium from the combustion chamber 32 via the evacuation port 95 for a given crankshaft revolution.
• the term "skips" means that, for a specific engine cycle, the controllable evacuation valve 96 does not open to allow the evacuation of fluid medium from the combustion chamber 32 through the evacuation port 95. Instead, the controllable evacuation valve 96 remains closed, preventing the fluid medium from being expelled during that engine cycle. This may allow for a more precis control of the engine braking operation.
• the controllable evacuation valve 96 can be provided and designed in several different ways.
• the controllable evacuation valve 96 is a conventional poppet valve.
• the poppet valve is disposed in the cylinder head 30b.
• the controllable evacuation valve 96 is arranged at the end of the evacuation port 95 (towards the cylinder 30), as may be gleaned from Fig. 4 .
• the controllable evacuation valve 96 can also be controlled in several different ways.
• the controllable evacuation valve 96 is configured to be controllable by a corresponding actuator (not shown) of the controllable valve actuation assembly 63.
• the ICE system 10 comprises the controllable valve actuation assembly 63 for actuating the controllable evacuation valve 96.
• the actuator is an integral part of the controllable valve actuation assembly 63.
• the controllable valve actuation assembly 63 is e.g. a camshaft-driven valve actuation system, which comprises a camshaft.
• the controllable valve actuation assembly 63 is here arranged and configured to actuate all valves, i.e.
• the controllable valve actuation assembly 63 is adapted to actuate the EGR control valve 88, controllable evacuation valve 96 and controllable intake valves 37 in accordance with one or more lift modes during the two-stroke operation of the ICE 20.
• the EGR control valve 88, the controllable evacuation valve 96 and the controllable intake valve 37 may be actuated by a common camshaft 63 having three spaced apart actuators (cam lobes).
• the EGR control valve 88 is configured to be controllable by an actuator of the controllable valve actuation assembly 63 in the form of a variable valve actuation system.
• variable valve actuation system is a camless system, such as a flow control valve assembly.
• a flow control valve assembly typically comprises an actuator in the form of a hydraulic, electric, and/or a pneumatic actuator.
• the controllable valve actuation assembly 63 is configured to be controlled by a control system, such as the controller 90 (as illustrated in Fig. 1 ).
• controllable evacuation valve 96 is also controllable in response to an engine braking command from a control system, such as the controller 90 (as illustrated in Fig. 1 ).
• the engine braking command typically contains a signal, and/or instructions, to the controllable valve actuation assembly 63 for controlling the controllable evacuation valve 96 to open the passage in the evacuation port 95 such that compressed air can be released from the combustion chamber 32 and through the evacuation port 95, thereby providing an engine braking operation of the ICE 20.
• the controllable evacuation valve 96 is thus configured to provide an engine braking operation of the ICE 20.
• engine braking typically refers to an operation of the ICE 20 when the retarding forces within the ICE 20 are used to slow the vehicle 1 down.
• the controllable evacuation valve 96 is controlled to an open state, or at least a partly open state, thereby releasing compressed air trapped in the cylinder 30 via the evacuation port 95 and slowing down the vehicle 1.
• the evacuation port 95 is typically fluidly connected to a subsequent fluid conduit, such as the fluid conduit 98, as depicted in the Fig. 4 .
• the evacuation port 95 is configured to be in fluid communication with a fluid conduit for transportation of the fluid medium.
• the evacuation port 95 is here arranged in fluid communication with the fluid conduit 98 arranged to route the fluid medium away from the evacuation port 95.
• the fluid conduit 98 can be arranged in fluid communication with a storage tank (not illustrated) for storing compressed air for other use within the ICE system 10, or be routed to a position before, or after, a turbine 71 of a turbocharger system 70.
• the flow of fluid medium from the evacuation port 95 is allowed to flow to the exhaust duct 61 downstream a position of the EGR conduit.
• the ICE system 10 may perform the following method: In a step S10, when a piston is travelling down from TDC to BDC in one of the cylinders during expansion of the combustibles and a corresponding exhaust port is uncovered, the effective work stroke is ended, and the gases are exhausted through the exhaust port. Subsequently, in a step S20, the intake valve(s) of one of the cylinder opens and the cylinder is purged by incoming air fed by the aforementioned boosting system (e.g. by the turbocharger arrangement 70 and the positive displacement device 23). At this stage there is no fuel present in the boost mass or the cylinder. Then, in step S30, the piston reaches BDC.
• the aforementioned boosting system e.g. by the turbocharger arrangement 70 and the positive displacement device 23
• step S40 the piston starts to move up towards its TDC and the piston eventually covers the exhaust port again.
• the fuel injector arrangement is operated to inject e.g. hydrogen fuel.
• the hydrogen fuel is injected into the intake port, creating the pressure pulse from the injected hydrogen fuel.
• the ICE system 10 is operated to start injecting hydrogen gas into the air stream in the plenum 25, thus feeding air and hydrogen into the cylinder.
• the injection starts after the intake valve has opened just after the initial scavenging (cylinder purge) and ends before the intake valve closes which provides an essentially intake tract free of combustible gas.
• Initial scavenging of the cylinder (purging) is the time between IVO and start of hydrogen gas injection.
• step S50 the piston continues to travel up (about halfway) through the stroke and the intake valves closes.
• step S60 the piston travels to just before TDC, TDC or just after TDC (i.e. close to TDC).
• the ignition source e.g. a spark plug
• step S80 the piston is forced down in the work stroke (expansion).
• step S90 the cycle repeats from above steps S10 to S80.
• the operation of purging, scavenging and subsequent fuel injection operation, creating a boost pulse, as well as the ending of fuel injection where hydrogen (H2)/air mixture is pushed into the cylinder allows for emptying the plenum 25, while the positive displacement device 23 is operated to push in fresh air in the plenum 25.
• the arrangement and configuration of the ICE system 10 provides for avoiding, or at least reducing the risk of having hydrogen mixture in the plenum 25, hence, reducing the risk for backfire.
• the intake valves are opened all at the same time, a flow effect in the whole cross section area of the cylinder can be obtained so that the cylinder is filled homogenously from top to bottom, driving out the exhaust gases so that low mixing between the fresh charge air and the warm exhaust combustibles is obtained. This may be useful so as to reduce the mixture temperature and residuals in preparation of the mixture.
• the intake valves are then completely closed when the piston is halfway up in the cylinder which reduces the risk of a backfire.
• the ICE system is operable to flush out the exhaust gases from the entire cylinder with EGR as soon as possible after the exhaust port is exposed. Afterward, fresh gas and EGR are filled together in the cylinder.
• the combustion chambers can be designed in several different manners and may be any one of a flat, hemispherical, or pent roof design with only intake valves. It may be beneficial to cover a large area of the combustion chamber with valves so that the cylinder filling can be made in an efficient manner.
• All moving parts in the ICE 20 may generally be lubricated by means of conventional pressure lubrication. Other options are also possible.
• the corresponding positive displacement device 23 and the plenum 25 of the air intake manifold 22 are typically considered to be the cold components and may be made from an aluminum alloy.
• the air intake manifold 22 may typically be fastened to the cylinder heads that may be warmer, which is made of cast iron or steel. This may minimize the risk of hydrogen embrittlement since no gas containing hydrogen comes into contact with any iron or steel that is colder than 150 degrees C, which is the threshold when hydrogen embrittlement is considered to occur.
• the ICE system 10 can be cooled in several different ways.
• the ICE system 10 comprises a controlled low temperature coolant circuit for temperature control of the CAC (Compressed Air Cooler) and/or the EGR cooler.
• CAC Compressed Air Cooler
• EGR cooler the condensation level of the returned water from the combustibles (H2 produce H2O when combusted) is controlled.
• the ICE system 10 may not be restricted to a system with one single pair of cylinders 30, 40, but can also be implemented in an ICE system comprising four cylinders, six cylinders etc. Hence, the ICE system 10 may have a minimum of two cylinders, but multiples of two cylinders may likewise be possible.
• each arrangement of a pair of neighboring cylinders may have a corresponding first intake manifold with a corresponding positive displacement device and a corresponding second intake manifold, as described herein.
• a four-cylinders ICE will have two positive displacement devices and a six-cylinder ICE will have three positive displacement devices.
• Such ICE system may also use a positive displacement device with a plurality of separated sections, wherein each section is provided to cooperated with a given pair of cylinders.
• the flow of fluid (air) to each pair of cylinders should be separated from each other.
• the cylinder pairs can be arranged spaced-apart so as to allow for ignition of fuel for three cylinders at once (flat crank) or arranged evenly offset from each other for an evenly spread firing order. In this way, it becomes possible to charge one cylinder in the pair at the time without creating unwanted pulsation since one cylinder is in its intake stroke while the other one is in its work stroke.
• Example 1 An internal combustion engine ICE system 10 for a vehicle 1, the ICE system comprising: a two-stroke ICE 20 operable on a fuel 50; the ICE having at least one cylinder 30 with a cylinder wall 30a and further a reciprocating piston 31 moveable in an axial direction A within the cylinder between a bottom dead center BDC and a top dead center TDC, the at least one cylinder at least partly defining a combustion chamber with a top end 33 of the piston; a first intake manifold 22 for receiving fresh air, the first intake manifold configured to be in fluid communication with a first intake port 35 arranged at a top end 36 of the at least one cylinder, the first intake port configured to be in fluid communication with the combustion chamber; an exhaust port 38 arranged axially distal from the top end of the at least one cylinder, allowing the first intake port and the exhaust port to be fluidly separated by the piston; a second intake manifold 86 configured
• Example 2 ICE system of example 1, wherein the positive displacement device is controllable in response to an operational parameter of the ICE system.
• Example 3 ICE system of example 2, wherein the operational parameter of the ICE system is any one of engine load, engine speed and exhaust temperature.
• Example 4 ICE system of any one of the preceding examples, wherein the ICE system is configured to operate at a target lambda value of about one.
• Example 5 ICE system of any one of the preceding examples, wherein the ICE system comprises a turbocharger arrangement 70 having a turbocharger turbine 71 operatively connected to a turbocharger compressor 72, wherein the turbocharger compressor is arranged in an air intake conduit 73 to the first intake manifold 22, and wherein the turbocharger turbine is arranged in the exhaust duct 61 so as to drive the turbocharger compressor.
• the ICE system comprises a turbocharger arrangement 70 having a turbocharger turbine 71 operatively connected to a turbocharger compressor 72, wherein the turbocharger compressor is arranged in an air intake conduit 73 to the first intake manifold 22, and wherein the turbocharger turbine is arranged in the exhaust duct 61 so as to drive the turbocharger compressor.
• Example 6 ICE system of example 5, wherein EGR conduit is adapted to connect to the exhaust duct at a position 85 upstream the turbocharger turbine.
• Example 7 ICE system of any one of the preceding examples, wherein the EGR control valve is controllable to purge the at least one cylinder from combusted gas after an ICE work stroke by supplying EGR gas to the combustion chamber via the second intake port.
• Example 8 ICE system of any one of the preceding examples, wherein the EGR control valve is configured to be controllable by an actuator of a variable valve actuation system.
• Example 9 ICE system of any one of the preceding examples, wherein the second intake port is a swirl intake port configured to create a swirling motion of the fluid medium.
• Example 10 ICE system of any one of the preceding examples, wherein the at least one cylinder further comprises an evacuation port 95 arranged at the top end of the at least one cylinder, the evacuation port being configured to be in fluid communication with the combustion chamber, and a controllable evacuation valve 96 disposed in the evacuation port and configured to provide an engine braking by controlling the flow of fluid medium through the evacuation port.
• Example 11 ICE system according to example 10, wherein the controllable evacuation valve is controllable in cooperation with the movement of the piston such that the controllable evacuation valve permits evacuation of fluid medium from the combustion chamber via the evacuation port during a compression stroke.
• Example 12 ICE system according to any one of the preceding examples, wherein the ICE system is a spark-ignition ICE system, and the at least one cylinder having an ignition source 34 arranged in the combustion chamber.
• Example 13 ICE system according to any one of the preceding examples, wherein the ICE system comprises a fuel injector arrangement for injecting fuel, the fuel injector arrangement being arranged in the combustion chamber, or the fuel injector arrangement being arranged upstream the first intake port to provide a port fuel injection arrangement.
• the ICE system comprises a fuel injector arrangement for injecting fuel, the fuel injector arrangement being arranged in the combustion chamber, or the fuel injector arrangement being arranged upstream the first intake port to provide a port fuel injection arrangement.
• Example 14 ICE system according to any one of the preceding examples, wherein the at least one cylinder is a first cylinder and the piston is a first piston, and the ICE further having a second cylinder forming a pair of cylinders with the first cylinder, the second cylinder accommodating a corresponding reciprocating second piston 41 operable between a bottom dead center and a top dead center, and further at least partly defining a second combustion chamber 42 with a top end 43 of the second piston, wherein the second cylinder further comprises a corresponding ignition source 44 arranged in the second combustion chamber, at least one corresponding intake port 45 arranged at a top end 46 of the second cylinder and in fluid communication with the second combustion chamber, and further a corresponding exhaust port 48 arranged axially distal from the top end of the second cylinder, allowing the at least one corresponding intake port and the corresponding exhaust port to be fluidly separated by the second piston.
• the second cylinder further comprises a corresponding ignition source 44 arranged in the second combustion chamber, at least one corresponding intake port 45
• Example 15 ICE system according to example 14, wherein the first and second cylinders are separated from each other with a crank angle of 180 degrees.
• Example 16 ICE system according to example 14 or example 15, wherein the first intake manifold 22 having a corresponding positive displacement device 23 configured to receive and feed intake air to the pair of cylinders, the corresponding positive displacement device further being arranged in the air intake manifold to separate an upstream intake tract 24 from a downstream plenum 25 of the air intake manifold, the downstream plenum being in fluid communication with each one of the first and second cylinders of the pair of cylinders.
• Example 17 ICE system according to any one of the preceding examples, wherein the ICE system is a hydrogen ICE system configured to operate on a gaseous fuel containing a hydrogen-based gaseous fuel.
• Example 18 A vehicle comprising an internal combustion engine system according to any one of the examples 1 to 17.
• upstream and downstream refer to the relative direction with respect to fluid flow in a fluid pathway.
• upstream refers to the direction from which the fluid flows
• downstream refers to the direction to which the fluid flows.
• longitudinal refers to a direction at least extending between axial ends of a particular component, typically along the arrangement or components thereof in the direction of the longest extension of the arrangement and/or components.
• vertical refers to the axial direction.
• Relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present.

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• 2024
  • 2024-06-11 EP EP24181288.2A patent/EP4663935A1/fr active Pending

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