Classifications

• • 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
  • F02D13/0223—Variable control of the intake valves only
  • F02D13/0226—Variable control of the intake valves only changing valve lift or valve lift and timing
• • 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
  • F01L9/00—Valve-gear or valve arrangements actuated non-mechanically
  • F01L9/20—Valve-gear or valve arrangements actuated non-mechanically by electric means
• • 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
  • F02D41/0002—Controlling intake air
• • 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
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/04—Introducing corrections for particular operating conditions
  • F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
  • F02D41/062—Introducing corrections for particular operating conditions for engine starting or warming up for starting
  • F02D41/064—Introducing corrections for particular operating conditions for engine starting or warming up for starting at cold start
• • 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
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L2800/00—Methods of operation using a variable valve timing mechanism
  • F01L2800/19—Valves opening several times per stroke
• • 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
• • 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
  • F02D13/0253—Fully variable control of valve lift and timing using camless actuation systems such as hydraulic, pneumatic or electromagnetic actuators, e.g. solenoid valves
• • 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
• • 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
  • F02D2013/0292—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation in the start-up phase, e.g. for warming-up cold engine or catalyst
• • 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
  • F02D41/0002—Controlling intake air
  • F02D2041/001—Controlling intake air for engines with variable valve actuation
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/12—Improving ICE efficiencies
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/40—Engine management systems

Definitions

• the invention relates to a method for reducing hydrocarbon emissions from a cold engine. It also relates to a device for implementing this method and an internal combustion engine using the method and / or the device.
• hydrocarbon emissions with a cold engine are greater in the case where the engine uses electrically-controlled type valves, in particular electromagnetic or electrohydraulic, while they are less important in the case where the valves are controlled conventionally by a camshaft.
• the injection valve 14 is closed, that is to say applied against its seat 16, when the fuel is directed towards the rear face of the valve 14 by means of an injector 18.
• the lift time of the valve is independent of the engine speed.
• the time for the valve to reach its maximum lift is relatively lower at low speed than at high speed, which increases the emission of unburned hydrocarbons when the engine is idling.
• the invention relates to a method for reducing hydrocarbon emissions by a cold-internal combustion engine having electrically operated intake valves, characterized in that the opening of the valve is controlled in two phases, a first phase mainly for the admission of fuel and a second phase mainly for the admission of air, the opening of the valve being substantially lower in the first phase than in the second phase, so that the fuel is sprayed in the form of fine droplets during this first phase.
• the operation of the electrically actuated valve motor is similar to that of the camshaft drive motor at the beginning of the valve opening, i.e.
• the first, low-lift phase is for example in the form of a bearing, the valve opening rapidly to reach the first lift value and remaining at this first value, relatively low, during the rest of the first phase.
• the lifting of the valve increases gradually.
• the invention also applies in the case where the same intake valve opens twice during the intake phase of the engine, that is to say with a pilot lift and a main lift, these two lifts being separated by a closing step of the valve.
• valve or valves are (are) closed while the piston is in the down phase, which creates a vacuum in the cylinder.
• the turbulence of the gases in the chamber is increased.
• This level of turbulence is optimized if the opening of the valve is substantially at the half-stroke of the piston, that is to say at the moment when the piston speed is maximum.
• an initial low lift phase is planned for both the pilot lift and the main lift.
• the low lift at the beginning of the main lift also has the advantage of increasing the turbulence of the gases in the chamber. Increased turbulence in the cylinder allows to degrade the ignition advance and thus to retard combustion during the engine operating cycle. As a result, the exhaust gases are hotter, which accelerates the heating of the catalyst and thus the elimination of hydrocarbons.
• combustion in the cycle is delayed in order to purge hotter gases which are then directed to a combustion catalysis system.
• fuel admission occurs during both the pilot lift and the main lift.
• the pilot lift occurs while the exhaust valves are still open.
• the pilot lift of the (or) intake valve (s) allows to discharge exhaust gases in the intake duct.
• the low amplitude lift at the beginning of the pilot lift is intended to limit the amount of exhaust gas enclosed in the cylinder and to control this amount, that is to say to limit its variations as a function of time .
• double lift and low amplitude lift at the beginning of each lift we obtain an optimization of the combustion during the second lift (main lift), and an activation of the (or) catalyst (s) ) faster.
• the low amplitude lift at the beginning of the pilot lift as indicated above, it is obtained that the re-aspiration into the cylinder of some of the unburned hydrocarbons, which are burned during the following cycle, is well controlled.
• the low amplitude lift is provided only for the main lift.
• the recirculation of the flue gases is carried out by the offset of the exhaust, the closure of the exhaust valves occurring after the point high dead (PMH) intake, one can dispense with controlling the amount of flue gases by means of a low lift of the pilot lift.
• PMH point high dead
• two intake valves per cylinder are provided and a valve is used to provide the pilot lift and the second valve is used to perform the main lift.
• these two valves can be actuated in synchronism, that is to say that the two valves can be used both to carry out the pilot lift and to carry out the lifting main.
• the invention also relates to a device for implementing the method defined above which comprises valve control means for making the openings and at least one catalyst system for the combustion of the burned exhaust gas.
• Figure 1 already described, is a diagram showing the variation of an intake valve lift for a camshaft controlled valve and for a conventionally controlled valve by electric control;
• Figures 2 and 3, already described, are diagrams illustrating the injection and the valve opening;
• Figures 4, 5 and 6 are diagrams illustrating valve opening commands according to several embodiments of the invention;
• Figure 7 is a diagram illustrating the control of exhaust and intake valves.
• the embodiment of the invention that we are going describe with reference to the drawings relates to a four-stroke type motor whose valves are controlled by electromagnet, in particular by polarized electromagnet.
• a control valves "flexible" type including any electrical control.
• the gasoline engine is of any type, that is to say that it is supercharged or not, with direct injection or not.
• the architecture of the engine is also arbitrary. It can be online, in V or flat.
• the valve control according to the invention relates to provisions for reducing the emissions of hydrocarbon pollutants when the engine is cold, that is to say when a catalyzed device (not shown) is not yet active.
• a start of the opening phase of an intake valve with a valve lift (that is to say a degree of opening) substantially less than the valve lift intervening is foreseen. later in the course of admission in the same cycle.
• FIG. 4 which is a diagram on which the crankshaft degrees (DV) have been plotted on the abscissa and the valve lift values on the ordinate, during a first phase 32 the valve lift has a value L 1n substantially less than the value L M during the second phase 34 of full opening of the valve.
• the first phase consists in conferring the lift L m in a step 30, that is to say that the lift L 1n is practically constant during the phase 32.
• the first opening phase corresponds for example to a valve lift of between 0.1 and 1 mm and the time 32 is from 1 to 4 ms.
• the first phase 32 makes it possible to spray the fuel deposited on the intake duct and the while during the second phase 34, the maximum lift makes it possible to fill the cylinder with air.
• the first valve lift phase 32i is of the ramp type, ie the lift Lm is reached at the end of the period 32i, the lift variation 36 being regular during this first phase 32i.
• the first phase of the lift extends over a time also between 1 and 4 ms and at the end of the first phase 32i, the opening or lifting is between 0.5 and 1 mm.
• the diagram of Figure 6 relates to the case where the inlet valve opens twice during the intake phase of the engine.
• the first lift 40 is a so-called pilot lift and the second lift 42 is a so-called main lift. Between these two lifts, the inlet valve is closed, which corresponds to the zone 44 in the diagram of FIG.
• the pilot lift and the main lift each have a first phase during which the opening of the valve is reduced.
• the reduced lift occurs during a first phase 46 before the top dead center (TDC) intake.
• the phase 46 starts between 60 DV and 0 DV before the top dead center, while the end of the phase 46 intervenes between 0 and 30 DV after the high dead point of admission.
• the low opening phase 46 of the intake valve makes it possible to limit the quantity of discharge gas (exhaust) enclosed. in the cylinder and make this quantity substantially constant.
• Fig. 7 which shows valve lifts as a function of crankshaft degree
• OE stands for exhaust opening
• FE stands for exhaust closure
• OA intake opening
• FA intake closure
• the closure 44 of the intake valve between the pilot lift and the main lift creates a vacuum in the cylinder while the valves are all closed and the piston is in the down phase. Under these conditions, at the beginning of the main lift, a gas movement is created which increases the turbulence in the cylinder. This turbulence is maximized if the opening of the valve occurs around the half-stroke position of the piston, i.e. when the piston speed is maximum.
• phase 48 low lift at the beginning of the main lift
• phase 48 occurs between 30 DV and 0 DV before mid-race.
• the end of this period 48 of minimum lift takes place between 0 and 30 DV after the half stroke of the piston.
• a low lift results in a higher gas velocity through the valve than when the lift is maximum.
• the fuel spraying is more important which optimizes the preparation of the air-fuel mixture, that is to say, to reduce the size of the droplets.
• the ignition can be delayed, that is to say that it can, in this case, degrade the ignition advance.
• the exhaust gases are at a high temperature, which increases the temperature of the (or) system (s) of catalysis.
• the second phase of the main lift allows to introduce the air necessary for combustion.
• the low amplitude lift is short and the fuel flow is high, not all fuel can enter the combustion chamber during low amplitude lift; in this case, fuel injection continues during the main lift.
• FIG. 6 shows the case where the first phase 46 of the lift 40 is in the form of a ramp and the case where the first phase 48 of the main lift 42 is in the form of a bearing. But, it is possible to confer some form on the variation of the emergence during these first phases.

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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)
• Valve Device For Special Equipments (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=35448273

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• 2005
  • 2005-05-03 FR FR0504507A patent/FR2885389B1/fr not_active Expired - Fee Related
• 2006
  • 2006-04-05 US US11/918,965 patent/US7881854B2/en not_active Expired - Fee Related
  • 2006-04-05 WO PCT/FR2006/050303 patent/WO2006117486A1/fr not_active Ceased
  • 2006-04-05 EP EP06726309A patent/EP1880094A1/de not_active Withdrawn

Non-Patent Citations (1)

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