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
  • F02B25/14—Engines characterised by using fresh charge for scavenging cylinders using reverse-flow scavenging, e.g. with both outlet and inlet ports arranged near bottom of piston stroke
  • F02B25/145—Engines characterised by using fresh charge for scavenging cylinders using reverse-flow scavenging, e.g. with both outlet and inlet ports arranged near bottom of piston stroke with intake and exhaust valves exclusively in the cylinder head
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/02—Valve drive
  • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
  • F01L1/047—Camshafts
  • F01L1/053—Camshafts overhead type
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/34—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
  • F01L1/344—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/46—Component parts, details, or accessories, not provided for in preceding subgroups
  • F01L1/462—Valve return spring arrangements
  • F01L1/465—Pneumatic arrangements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
  • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
  • F02D13/0261—Controlling the valve overlap
  • F02D13/0265—Negative valve overlap for temporarily storing residual gas in the cylinder
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
  • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
  • F02D13/028—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation for two-stroke engines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D15/00—Varying compression ratio
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D23/00—Controlling engines characterised by their being supercharged
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
  • F02D41/0027—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures the fuel being gaseous
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
  • F02D41/0047—Controlling exhaust gas recirculation [EGR]
  • F02D41/006—Controlling exhaust gas recirculation [EGR] using internal EGR
  • F02D41/0062—Estimating, calculating or determining the internal EGR rate, amount or flow
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/30—Controlling fuel injection
  • F02D41/3011—Controlling fuel injection according to or using specific or several modes of combustion
  • F02D41/3017—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used
  • F02D41/3035—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used a mode being the premixed charge compression-ignition mode
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/02—Valve drive
  • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
  • F01L1/047—Camshafts
  • F01L1/053—Camshafts overhead type
  • F01L1/0532—Camshafts overhead type the cams being directly in contact with the driven valve
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/12—Transmitting gear between valve drive and valve
  • F01L1/18—Rocking arms or levers
  • F01L1/185—Overhead end-pivot rocking arms
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/02—Valve drive
  • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
  • F01L1/047—Camshafts
  • F01L1/053—Camshafts overhead type
  • F01L2001/0537—Double overhead camshafts [DOHC]
• • 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
  • F02B17/00—Engines characterised by means for effecting stratification of charge in cylinders
• • 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
  • F02B75/00—Other engines
  • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
  • F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
  • F02B2075/025—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two
• • 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
  • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
  • F02B37/004—Engines characterised by provision of pumps driven at least for part of the time by exhaust with exhaust drives arranged in series
• • 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
  • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
  • F02B37/013—Engines characterised by provision of pumps driven at least for part of the time by exhaust with exhaust-driven pumps arranged in series
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
  • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
  • F02D13/0203—Variable control of intake and exhaust valves
  • F02D13/0215—Variable control of intake and exhaust valves changing the valve timing only
  • F02D13/0219—Variable control of intake and exhaust valves changing the valve timing only by shifting the phase, i.e. the opening periods of the valves are constant
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/30—Controlling fuel injection
  • F02D41/3011—Controlling fuel injection according to or using specific or several modes of combustion
  • F02D41/3017—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used
  • F02D2041/3052—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used the mode being the stratified charge compression-ignition mode
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2200/00—Input parameters for engine control
  • F02D2200/02—Input parameters for engine control the parameters being related to the engine
  • F02D2200/10—Parameters related to the engine output, e.g. engine torque or engine speed
  • F02D2200/101—Engine speed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2400/00—Control systems adapted for specific engine types; Special features of engine control systems not otherwise provided for; Power supply, connectors or cabling for engine control systems
  • F02D2400/04—Two-stroke combustion engines with electronic control

Definitions

• the invention relates to the field of carbon-free thermal energy production.
• Reciprocating internal combustion engines burn hydrocarbons in the gas phase via the mechanism of the propagation of a flame front where the products already burned diffuse into the fresh products to bring the latter to their self-ignition temperature which triggers the reactions in chains of live combustion.
• the slowness of gas diffusion handicaps the thermal efficiency of reciprocating engines by the angular duration of combustion which produces negative work before the top dead center of the pistons and insufficiently expanded gases after said top dead center.
• the very low flame speed of ammonia compounds this problem to the point where ammonia must be mixed with hydrogen to initiate stable combustion.
• HCCI Homogeanous Charge Compression Ignition
• This flameless combustion process consists of heating a homogeneous fuel mixture by compression to its auto-ignition temperature. Unlike progressive surface heating of a flame front, this volume heating process triggers auto-ignition simultaneously throughout the entire fuel charge with the risk of a destructive detonation for the engine.
• the object of the present invention consists of stratifying the temperature of the reactive medium to confer progressiveness to the self-ignition by compression.
• the invention can be applied to all fuels in a 4-stroke cycle and in a 2-stroke cycle via different gas exchange strategies.
• the 2-stroke cycle is best suited to low-carbon, difficult-to-flammable fuels such as methane and ammonia.
• the invention relates to a method of operating a reciprocating internal combustion engine, each cylinder of which receives at each cycle a fresh mass MA of an isothermal mixture of combustion air and a combustible gas which replaces the mass of gases burned in the previous cycle characterized in that a hot mass MB of burned gases present in the cylinder diffuses throughout the fresh mass MA, during the gas exchange phase and the compression phase, to form a reactive mixture totally stratified in temperatures of which the hottest isothermal stratum reaches its self-ignition temperature before top dead center under the effect of its compression by the piston and of which the less hot isothermal strata successively reach their temperature d self-ignition under the effect of their compression following the thermal expansion of the isothermal strata already burned.
• the temperature and mass concentration of combustible gas can be identical at all points of the fresh mass MA in order to standardize the temperature of the gases resulting from combustion.
• the coldest isothermal stratum of the reactive mixture can reach its auto-ignition temperature after the top dead center of the piston in order to limit the maximum pressure and temperature of the cycle.
• the surface extent of the isothermal strata of the reactive mixture can decrease when their temperature increases in order to provide progressiveness to the rate of heat release from combustion.
• the hottest area of the reacting medium may be located near the center of the combustion chamber. This zone can also be located against a heat-insulated piston. This can make it possible to provide progressiveness to the combustion heat release rate and to limit thermal leaks towards the piston body.
• a sensor may be located in a cylinder to continuously transmit the angular position of the combustion relative to the top dead center of the piston to a computer motor control which controls actuators acting on the temperatures of the isothermal strata of the reactive mixture to place said angular position on a value conforming to a map of the torque/operating speed field of the motor stored in the computer memory.
• the temperatures of the isothermal layers of the stratified reactive mixture can be controlled via the MB/MA ratio of the masses retained in the cylinder.
• the temperatures of the isothermal strata of the stratified reactive mixture can be controlled via the effective compression ratio of the piston which compresses the MA+MB mixture.
• a pressure sensitive sensor located in a cylinder can detect the angular position of the maximum pressure of the cycle and the engine control computer can position said maximum pressure after the top dead center of the piston to coincide with the end of combustion according to the invention.
• the engine control computer can act on the temperatures of the isothermal layers of the stratified reactive mixture by individually or collectively controlling at least some of the following actuators: camshaft phase shifters, variable section turbine distributors, by -variable area turbine pass, variable area air refrigerant bypasses.
• the method according to the invention is particularly effective in the case of a reciprocating internal combustion engine operating on the 2-stroke cycle under swept, each cylinder of which receives at each cycle a fresh mass MA of an isothermal mixture of combustion air and of a combustible gas which replaces the mass of gases burned in the previous cycle characterized in that a hot mass MB of burned gases retained in the cylinder diffuses throughout the entire fresh mass MA, during the gas exchange phase and the compression phase, to form a reactive mixture totally stratified in temperature, the hottest isothermal stratum of which reaches its auto-ignition temperature before top dead center under the effect of its compression by the piston and the less isothermal strata of which hot successively reach their self-ignition temperature under the effect of their compression following the thermal expansion of the isothermal strata already burned.
• Said engine may comprise several identical cylinders provided with exhaust ports and intake nozzles closed according to a chronology which successively comprises: in the vicinity of the bottom dead center of the piston, the simultaneous opening of the exhaust ports followed by the simultaneous opening of the intake nozzles; between bottom dead center and top dead center of the piston, the simultaneous closing of the intake nozzles followed by the simultaneous closing of the exhaust ports, the engine control computer controlling the closing angle of the exhaust ports to position the combustion by simultaneously modulating the MB/MA ratio and the effective compression ratio of the stratified reactive mixture MA+MB.
• Said engine may comprise several cylinders provided with intake nozzles connected to an intake plenum and exhaust ports connected to an exhaust plenum; the inlet plenum being pressurized to a pressure PA by the compressor of a high pressure turbocharger HP via an air refrigerant HP, the exhaust plenum pressurized to a pressure PE slightly lower than the pressure PA supplying the HP turbine of the HP turbocharger via a TC power turbine.
• Said engine may include a LP turbocharger whose compressor supplies air to the HP compressor via an HP refrigerant and whose turbine is supplied with gases burned by the turbine of the HP turbocharger.
• the camshafts of said engine can be mechanically connected to the crankshaft via a common phase shifter controlled by the computer to angularly position the combustion via simultaneously the compression ratio and the rate of burnt gases of the MA+MB mixture.
• a variable flow section of the HP turbocharger turbine distributor can be controlled by the engine control computer to adjust the fuel richness of the mass MA.
• a variable flow section of the distributor of the power turbine TC can be controlled by the engine control computer to position the combustion and a variable flow section of the turbine of the HP turbocharger can be controlled by the engine control computer to set the richness of the MA mass in accordance with a map stored in the computer memory.
• the face of the piston can be covered by a heat shield which exchanges its heat with the jet of carbureted air to cancel the heat flow towards the piston body.
• the stroke of the pistons of said engine can be close to the diameter of the cylinders, the combustible gas of mass MA being ammonia NH3, the ratio MB/MA being greater than 0.70, the volumetric expansion rate being between 7 and 9 and the volumetric compression rate of the pistons being between 3 and 5.
• FIG. 1 is a schematic view of the air loop of a heavily supercharged turbo-compound engine
• FIG. 2 is a view of the thermodynamic cycle described by the turbo-compound engine of Figure 1
• FIG. 3 is a schematic view of the internal aerodynamics of a cylinder of the turbo-compound engine in Figure 1
• FIG. 4 is a cross section of a cylinder of the turbo-compound engine of Figure 1
• the key to the invention is the elimination of detonation of a homogeneous fuel charge which ruined the hopes raised by HCCI combustion at the end of the last century. It opens the way to rapid self-ignition by compression of difficult-to-ignite fuels by raising the thermal level of the reactive medium by other means than pure compression. As a bonus, it makes it possible to reduce the production of nitrogen oxides by diluting the reactive medium without reducing the combustion start temperature.
• the invention achieves its three objectives by constructing, in a reciprocating engine cylinder, a reactive medium fully stratified in temperature by mixing a fresh isothermal carbureted mass MA with a hot mass MB of burnt gas retained in the cylinder.
• the invention is based on the laws of chemical kinetics which govern the oxidation of a combustible mixture in the gas phase stipulating that the speed of the reactions increases exponentially with the local temperature.
• the exponential effect of temperature means that volume heating by compression of a reactive medium stratified in temperature triggers a self-ignition front which circulates against the temperature gradient between its hottest isothermal stratum and its coldest isothermal stratum until the fuel runs out.
• the object of the invention is therefore a reciprocating internal combustion engine, each cylinder of which receives at each cycle a fresh isothermal mass MA of a mixture of combustion air and a combustible gas which replaces the mass of the gases burned in the cycle.
• a hot mass MB of burnt gases retained in the cylinder diffuses throughout the fresh mass MA, during the gas exchange phase and the compression phase, to form a reactive mixture totally stratified in temperature of which the hottest isothermal stratum reaches its auto-ignition temperature under the effect of its compression by the piston before its top dead center TDC and of which the less hot isothermal strata successively reach their auto-ignition temperature under the effect of their compression following the thermal expansion of the isothermal strata already burned.
• the process of the invention is no longer effective after TDC when the volumetric expansion of the piston exceeds the thermal expansion due to combustion.
• it is possible to terminate combustion after TDC given that, when heating by compression becomes insufficient to bring the coldest strata to the self-ignition threshold, the diffusion of the combustion front Self-ignition in fresh produce can complement warming from compression.
• Combustion is optimal when the concentration of fuel in the fresh mass MA is constant in order to standardize the end-of-combustion temperature in the cylinder.
• the invention recommends that the carburization of the mass MA takes place in an intake plenum of sufficient volume so that the diffusion of the combustible gas in the combustion air has time to reach thermodynamic equilibrium.
• Thermal stratification according to the invention thus generates in the reactive medium an inverse gradient of fuel mass concentration which homogenizes the final combustion temperature. Indeed, the hottest strata rich in burnt gases and poor in fuel undergo weak chemical heating, while the cooler strata poor in burnt gases and rich in fuel undergo strong chemical heating. This homogeneity of combustion temperatures optimizes the power of the cycle and eliminates hot spots that generate nitrogen oxides.
• the invention makes it possible to self-ignite all fuels, regardless of the effective compression ratio of the reactive medium and the auto-ignition temperature. -ignition of the fuel, by controlling the MB/MA ratio of the masses retained in the cylinder before their compression.
• the chemically inert ballast of recycled burnt gas MB which is stationed in the cylinder retains its internal energy with the exception of thermal leaks in the walls. During compression-expansion cycles it transfers internal energy to the reactive medium to initiate combustion and recovers it simultaneously by diluting said combustion to limit the final temperature. The thermal efficiency of the cycle is thus optimized by complete, rapid and non-detonating combustion which takes place at a substantially constant volume near TDC.
• the geography of the stratification depends on the position and orientation of the intake nozzles, the position of the exhaust ports and the geometry of the cylinder and the combustion chamber limited by the piston and the cylinder head.
• the geography of stratification also depends on the initial temperatures of the cool mass MA and the hot mass MB, the ratio of the two masses MB/MA, the turbulence of the reactive medium and the duration of cohabitation of the two masses in the cylinder which sets the rate of advancement of the mixture.
• Thermal stratification is initiated naturally in a 2-stroke engine cylinder when the fresh mass MA sweeps away the burnt gases from the previous cycle. During this rapid transfer, the gas diffusion which develops at the boundary between the two masses brought into contact does not have time to reach thermodynamic equilibrium and generates a mixed zone stratified in temperature and fuel concentration.
• the invention structures the gas exchange to diffuse burnt gases throughout the fresh mass MA without evacuating carbureted air towards the exhaust.
• the invention includes means for positioning combustion optimally near the high point.
• a sensor located in the combustion chamber detects the angular position of the combustion in real time. This sensor permanently informs an engine control computer which controls actuators acting on the thermal level of the reactive medium, to position the auto-ignition at the end of the compression stroke in accordance with a map of the torque/operating speed field of the engine stored in computer memory.
• a sensor sensitive to gas pressure detects the maximum pressure of the cycle which coincides with the end of combustion.
• actuators which act instantly on the thermal level of the reactive medium we will cite, without limitation, camshaft phase shifters, turbine distributors with variable flow section, turbine bypasses with variable flow section, bypasses of air refrigerant with variable flow section.
• the inventor chose to continue the description of the invention in the architecture of 4-stroke engines where the intake and exhaust ports are located in a cylinder head and are closed by valves actuated by phase-shifting camshafts making it possible to disconnect the gas distribution diagram from the movement of the pistons, unlike single-current scavenging engines which have orifices located in the thickness of the cylinders closed by the pistons.
• the invention is presented in its preferred application in a light generator, for land and maritime transport and for the decentralized production of electricity, driven by a two-stroke turbocharged turbo-compound engine with a low energy rate. compression fueled with pure ammonia and rotating at constant speed. This particular application exploits all the advantages which characterize the invention.
• a generator engine (1) operating at 1500 revolutions per minute on the 2-stroke turbo-compound cycle has 6 cylinders (2) in line which successively ignite every 60 dv (crankshaft degrees) to separate the exchange of gases which are carried out through cylinder heads.
• the intake nozzles are connected to an intake plenum (3) pressurized to a pressure PA, and the exhaust ports are connected to an exhaust plenum (4 ) pressurized at a pressure PE lower than PA.
• the plenums are sufficiently large in relation to the volume of gas transferred at each cycle so that PA and PE are substantially constant in stabilized conditions at constant load.
• each cylinder is closed, on the one hand, by the flat face (5) of an axisymmetric cylinder head comprising an axial intake nozzle (6) formed around an intake valve ( 7) and four identical peripheral exhaust orifices (8) arranged in a square around the intake nozzle and closed by synchronous valves (9), and on the other hand, by the face (10) of an axisymmetric piston formed to return the jet of carbureted air (11) coming from the intake nozzle towards the cylinder head by diffusing into the burned gases to structure the stratification according to the decreasing isotherms (22), (23), (24).
• the piston face is covered by a hot heat shield which exchanges heat with the jet of carbureted air to cancel the heat flow to the piston body.
• the stroke of the pistons is equal to the diameter of the cylinder at 180 mm to provide in the cylinder head a flow section of the transfer ports compatible with the cylinder capacity.
• valves are returned to their seats by pneumatic springs (not shown) and their seats are recessed in the cylinder head to delay the effective opening of the ports during acceleration of the ports. valves and advance their effective closing during valve deceleration.
• FIG. 2 represents the pressure/volume diagram of the closed cycle.
• the intake valve and the exhaust valves are closed once per cycle by two identical overhead camshafts (12) synchronized on the engine shaft via a common controllable device (not shown) to shift the entire angular chronology of transfers fixed by the camshafts.
• the exchange of gases begins at the opening OA of the intake nozzle which follows the simultaneous opening OE of the exhaust ports at the end of expansion of the burnt gases when the piston slows down near its bottom dead center BDC, and ends with the simultaneous closing FE of the exhaust ports which follows the closing FA of the intake nozzle when the piston has accelerated towards its top dead center TDC and occupies a position P controlled by the common phase shifter of the shafts cams.
• the PA-PE pressure drop When the intake nozzle and the exhaust ports are opened simultaneously the PA-PE pressure drop generates a flow in the cylinder which is interrupted when the intake nozzle is closed to fix the mass of carbureted air MA who will participate in the cycle.
• the mass MA introduced into the cylinder is proportional to the temporal duration of opening of the intake nozzle which does not vary not with the phase shift of the camshafts.
• the burnt gases of a cycle are evacuated according to three successive mechanisms: between OE and OA the overpressure of the cylinder is suddenly discharged up to the pressure PE of the exhaust plenum; between OA and FA the fresh charge expels burnt gases towards the exhaust ports which are added to those discharged by the piston; between FA and FE, the piston alone continues the delivery of the burned gases until the cylinder closes.
• mass MA which does not depend on the phase shift of the camshafts
• the mass MA+MB retained in the cylinder and its compression rate depend on the position P of the piston when the cylinder closes which varies with the phase shift of the cams exhaust. It follows that the camshaft phase shifter, which controls the mass MA+MB of which MA remains constant, simultaneously controls the MB/MA ratio which sets the proportion of gases burned in the stratified mixture and its compression ratio.
• the turbo-compound turbine 17 can be mechanically connected via a reduction gear 21 to the motor shaft or to an auxiliary alternator.
• the flow section of the HP turbine distributor can be controlled to adjust the fuel richness in the intake plenum.
• the HP turbocharger (15) is supplied with combustion air via an air refrigerant (18) by a low pressure LP turbocharger (19) driven in rotation by a LP turbine (20) supplied with burnt gases by the HP turbine (16) .
• the position of the working turbine upstream of the HP and LP turbines optimizes engine efficiency at partial loads. Indeed, the reductions in engine torque controlled by the flow of fuel injected into the carburetor successively impact the rotation speed of the LP turbocharger then that of the HP turbocharger before impacting the expansion rate of the working turbine which sets the thermal efficiency of the cycle.
• the invention proposes a process manageable by the engine control computer which controls the carburetor and the camshaft phase shifter.
• the carburetor throttle is closed and the phase shifter positions the cams to advance the cylinder closure to the bottom dead center of the piston to maximize the air compression ratio and simultaneously advance the cylinder opening before bottom dead center to reduce the gas expansion rate.
• the rotation of the crankshaft by a starter triggers at each rotation a strong heating by compression of the air and a reduced cooling by an aborted expansion which discharges into the plenum of exhaust, via the exhaust ports, a fraction of the hot air partially re-aspirated into the cylinder by the residual stroke of the piston to its bottom dead center with a mass of fresh air from the intake plenum, via the ports intake openings later, adjusted by the carburetor butterfly.
• the first rotation will begin its cycle at ambient temperature and each subsequent rotation will add heat in the cylinder to reach the auto-ignition temperature of the fuel at the top dead center of the piston.
• the fuel is then injected into the carburetor to decouple the starter by initiating operation of the engine at idle in slightly supercharged naturally aspirated regulated by the engine control computer via the fuel injector and the throttle valve which respectively control the speed of the engine. rotation and the angular position of the combustion via the quantity and temperature of the recycled burnt gases.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=83355267

Family Applications (1)

Country Status (3)

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• 2022
  • 2022-06-14 FR FR2205767A patent/FR3136514A1/fr active Pending
• 2023
  • 2023-06-09 EP EP23736422.9A patent/EP4540512A1/de active Pending
  • 2023-06-09 WO PCT/FR2023/050823 patent/WO2023242501A1/fr not_active Ceased

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