Classifications

• • 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]
  • F02D41/005—Controlling exhaust gas recirculation [EGR] according to engine operating conditions
  • F02D41/0055—Special engine operating conditions, e.g. for regeneration of exhaust gas treatment apparatus
• • 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
  • 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
  • F02D41/12—Introducing corrections for particular operating conditions for deceleration
• • 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
  • F02D41/38—Controlling fuel injection of the high pressure type
  • F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
  • F02D41/401—Controlling injection timing
• • 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
  • F02D41/38—Controlling fuel injection of the high pressure type
  • F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
  • F02D41/402—Multiple injections
  • F02D41/405—Multiple injections with post injections
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D43/00—Conjoint electrical control of two or more functions, e.g. ignition, fuel-air mixture, recirculation, supercharging or exhaust-gas treatment
  • F02D43/04—Conjoint electrical control of two or more functions, e.g. ignition, fuel-air mixture, recirculation, supercharging or exhaust-gas treatment using only digital means
• • 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
  • F02D13/0207—Variable control of intake and exhaust valves changing valve lift or valve lift and timing
• • 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
  • F02D2200/60—Input parameters for engine control said parameters being related to the driver demands or status
  • F02D2200/602—Pedal position
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2250/00—Engine control related to specific problems or objectives
  • F02D2250/36—Control for minimising NOx emissions
• • 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
• • 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

Definitions

• TITLE Method and system for controlling a spark-ignition internal combustion engine in the kick-off phase.
• the technical field of the invention is the control of spark-ignition internal combustion engines, and more particularly, the control of such engines with a view to reducing the emission of polluting species.
• the after-treatment system generally includes a three-way catalyst which is capable of oxidizing unburned hydrocarbons (HC) and carbon monoxide (CO), and reducing nitrogen oxides (NOx).
• Spark-ignition engines operate substantially at richness 1 (i.e. with an air-fuel mixture in stoichiometric proportions), the quantities of fuel injected into the engine generally being adjusted so that the richness is regulated in a closed loop around the value 1.
• This predetermined value is both far enough from zero to allow sufficient oxidation of HC and CO, and far enough from the OSC value to allow sufficient reduction of NOx. It can be chosen experimentally and depends on a plurality of parameters including at least the flow rate of combustion gases passing through the catalyst and the temperature of the catalyst.
• the efficiency of treatment of the polluting species is only good from a fairly high temperature of the catalyst, from the around 400°C.
• this high temperature, and this quantity of stored oxygen OS intermediate between zero and the maximum oxygen storage capacity OSC of the catalyst may be difficult to obtain or may interfere with the driver's requests.
• the emissions post-treatment system and in particular the catalytic converter has previously been positioned by the engine control system (by controlling the richness of the engine output gases) at its optimum level of OS (acronym for "Oxygen Storage”: mass of oxygen stored in the catalytic converter) to optimally treat emissions.
• the temperatures of the various parts (catalyst, particle filter, etc.) of the post-treatment system drop. If the temperature drops below a threshold value, the post-treatment system can defuse. Such a loss of efficiency can thus take place during a long deceleration on a downward slope, for example.
• a so-called "catalyst purge” strategy increases the richness beyond stoichiometry (enrichment for example to 1, 1) to send rich gases to the exhaust in order to catalyst LOS returns to the expected OS target level. It is recalled that the rich species consume the oxygen stored in the catalyst.
• the modification of the level of OS takes a certain time during which the catalyst is not in a state to treat the NOx emissions at the exit of the engine. Indeed, the efficiency of post-treatment of NOx decreases heavily in a lean mixture until it is zero. A strong peak of NOx emissions is therefore observed at the exhaust outlet during this phase. This is amplified if the temperature of the aftertreatment system has dropped below a predetermined threshold. It is then necessary to heat it again before the exhaust gases can be processed. During this heating period, the emissions of nitrogen oxides NOx are not treated, regardless of the richness of the exhaust gases or the level of OS in the catalyst.
• the catalyst purge strategy also has the disadvantage of increasing fuel consumption (due to enrichment) and particulate emissions.
• the document FR3064683A1 describes a method for controlling a supercharged spark-ignition engine with a partial exhaust gas recirculation circuit at the intake (EGR).
• EGR exhaust gas recirculation circuit at the intake
• This publication aims to solve a problem of abnormal combustion peaks during the transitional phase as well as an increase in polluting emissions during recoupling.
• the document FR3072418 describes a method for controlling a spark-ignition engine with an EGR circuit in which, when the engine operates in the non-ignited state, in the absence of fuel injection and ignition, for example on a foot lift, the throttle body is not closed to limit pumping losses and an EGR valve is open to increase gas recirculation.
• the supply of oxygen to the catalytic system is thus limited, so that when the engine is restarted, nitrogen oxide emissions are limited.
• nitrogen oxide emissions are still relatively high because, the throttle valve being open, a still relatively high quantity of oxygen circulates despite the supply of EGR gas.
• the unexamined patent application FR1911059 discloses a method for adjusting the richness in a spark-ignition engine equipped with an upstream catalyst and a downstream catalyst.
• the richness is regulated in a closed loop, by a first regulator, on a setpoint value which is permanently corrected by a second regulator according to the difference between a calculated value of the quantity of oxygen stored (OS) in the catalyst upstream and an oxygen amount set point value.
• OS quantity of oxygen stored
• This oxygen set point value is within a range which is strictly comprised between a minimum OS threshold and a maximum OS threshold, which are permanently determined according to the flow rate of the exhaust gases passing through the upstream catalyst and the temperature of the upstream catalyst, and the overshoot of which corresponds respectively to the start of CO leaks or to the start of NOx leaks downstream of the upstream catalyst.
• a minimum OS threshold and a maximum OS threshold which are permanently determined according to the flow rate of the exhaust gases passing through the upstream catalyst and the temperature of the upstream catalyst, and the overshoot of which corresponds respectively to the start of CO leaks or to the start of NOx leaks downstream of the upstream catalyst.
• An object of the invention is a method for controlling a spark-ignition internal combustion engine of a motor vehicle, provided with a system for processing polluting species in the exhaust line comprising the following steps.
• valve lift instants can be offset up to a predetermined value.
• the predetermined value can be equal to the maximum stop.
• the circuit can be controlled so that the exhaust gas recirculation flow rate is maximum.
• variable valve lift system When the engine includes a variable valve lift system, to admit unburned exhaust gases, the variable valve lift system can be controlled to reduce the amplitudes and spreads of the intake lifts in order to degrade the filling efficiency engine intake.
• the predetermined instant of the combustion cycle can be between the combustion top dead center so as not to burn the injected fuel and an instant not generating oil dilution due to the spraying of the barrels by the jets of injector.
• the predetermined instant of the combustion cycle can be equal to 40° with respect to the combustion top dead center.
• the advantage of the control method according to the invention is to make it possible to reduce the peaks of nitrogen oxide emissions during reacceleration following a phase of lifting the accelerator pedal without requiring additional systems and to lower fuel consumption compared to the use of a catalytic converter.
• Another object of the invention is a control system for a spark-ignition internal combustion engine provided with a system for processing polluting species in the exhaust line and with a computer configured to carry out the steps of the control method defined above.
• FIG 1 illustrates the evolution of the valve lift as a function of the crankshaft angle over a combustion cycle according to the invention
• FIG. 1 illustrates the evolution of the valve lift as a function of the crankshaft angle over a combustion cycle without offset.
• the aim of the invention is to eliminate NOx emission peaks during an acceleration phase following a foot lifting phase with an optimized engine control method during the accelerator pedal lifting phase. making it possible to greatly reduce the flow of exhaust gas passing through the post-treatment system, and to have exhaust gas at stoichiometry (for example, richness equal to 1) with limited overconsumption of fuel.
• volumetric efficiency h t an ⁇ ⁇ is calculated by an equation called "filling formula" as the ratio between the mass of air actually sucked in compared to the mass of air which could theoretically have entered considering the total volume of the cylinders . It is calculated by applying the following equation.
• the value of the volumetric efficiency depends at least on the engine rotational speed and the pressure in the engine intake manifold. Then, depending on the technical definition of the engine, it may also depend on the adjustment of other equipment present.
• VVT (acronym for "Variable Valve Timing") valve lift offset system
• EGR exhaust gas recirculation system (acronym for "Exhaust Gas Recirculation") to saturate the intake manifold and substitute exhaust gases for the fresh air admitted
• VVL (acronym for "Variable Valve Lift”) to degrade the filling efficiency with an intake camshaft law with reduced lifts and spreads.
• Figure 2 illustrates the evolution of the valve lifts as a function of the crankshaft angle in such a case.
• a step of adjusting the position of a variable valve lift VVL (acronym for “Valve variable lift”) can be carried out, etc
• the valve opening law is modified (more or less high, more or less spread out) to modify the permeability of the engine's combustion chambers.
• control method In order to obtain exhaust gases at stoichiometry (for example, a richness equal to 1) with limited overconsumption, the control method also includes a specific ignition/injection step.
• the solution consists in carrying out a small amount of post-injection in the expansion phase. of the cycle without activating the ignition.
• the fuel thus injected does not burn in the cylinder but is evacuated to the exhaust in the catalyst where it contributes to the richness. This also makes it possible to generate an exotherm therein and to maintain its temperature for maximum post-treatment efficiency. The defusing of the post-treatment system due to a drop in temperature below the threshold value is thus avoided.
• the post-injection must thus be carried out after TDC combustion so as not to burn, which implies a rather high phase shift value with respect to the angular position of the crankshaft.
• the post injection must also be carried out so as not to generate an oil dilution due to the spraying of the barrels by the injector jets, which implies a value of phase shift with respect to the angular position of the crankshaft rather low .
• the optimal phase shift value with respect to the crankshaft therefore depends on the design of the injection/combustion system. Typically, an optimal value is 40°Vil.
• the flow of fresh air being low, the quantities of post-injected fuel are also low. It is then possible to be stuck on the minimum quantity that can be injected by the injection system (typically 2 mg/shot). In such cases, the number of injections per cycle is reduced (example: less than 4 per cycle for a 4-cylinder engine) so as to increase the quantity of fuel injected per injection.
• the exotherm created in the catalyst by the post injection makes it possible to maintain the internal temperature levels of the catalyst or even to improve them, which is favorable to the efficiency of treatment of the pollutants. On reacceleration, there is therefore no longer any peak in the emission of nitrogen oxides NOx and there is no longer any need to use a catalyst purge with enrichment.

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• 2021
  • 2021-03-01 FR FR2101953A patent/FR3120253A1/fr active Pending
• 2022
  • 2022-02-21 CN CN202280024264.3A patent/CN117616191A/zh active Pending
  • 2022-02-21 EP EP22706831.9A patent/EP4301970A1/de active Pending
  • 2022-02-21 WO PCT/EP2022/054193 patent/WO2022184480A1/fr active Application Filing

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