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
  • F02D41/30—Controlling fuel injection
  • F02D41/3011—Controlling fuel injection according to or using specific or several modes of combustion
  • F02D41/3076—Controlling fuel injection according to or using specific or several modes of combustion with special conditions for selecting a mode of combustion, e.g. for starting, for diagnosing
• • 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
  • F02D41/021—Introducing corrections for particular conditions exterior to the engine
  • F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
• • 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
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
  • F02D2041/1413—Controller structures or design
  • F02D2041/1432—Controller structures or design the system including a filter, e.g. a low pass or high pass filter
• • 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
  • F02D2041/389—Controlling fuel injection of the high pressure type for injecting directly into the cylinder
• • 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
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
  • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
  • F02D41/1446—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being exhaust temperatures
• • 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
  • F02D41/3023—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used a mode being the stratified charge spark-ignited mode
  • F02D41/3029—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used a mode being the stratified charge spark-ignited mode further comprising a homogeneous charge spark-ignited mode

Definitions

• the present invention relates to a four-stroke petrol engine with positive ignition for which:
• the fuel is directly injected into the combustion chamber via a high pressure fuel supply system; - the control parameters are calculated and applied by a central control unit,
• the exhaust gases are treated by one or more catalysts placed in the exhaust line.
• the engine control unit processes the various engine stresses (driver's wishes, on-board electronic systems such as trajectory control or gearbox, etc.), synthesizes them and draws up a torque setpoint to be achieved by acting on the command parameters that are:
• the engine control unit has several combustion modes to ensure this torque setpoint.
• the richness of the mixture is an adimensional value defined as the ratio between the air / petrol proportions of a stoichiometric mixture and the same air / petrol proportion of the mixture in the combustion mode considered:
• the richness is equal to 1 when the mixture is stoichiometric
• - the richness is greater than 1 when the proportion of gasoline in the mixture is greater than that of the stoichiometric mixture.
• the mixture is said to be "rich"
• the combustion mode ensuring the best performance is the so-called "stratified" mode.
• the fuel is injected into the combustion chamber at the end of the compression phase so that the richness of the mixture near the spark plug at the time of ignition is sufficient to ensure combustion.
• the overall mixture has a very large excess of air (average richness of the order of 0.4) which allows:
• This "stratified" combustion mode is therefore preferred for low torque demands but cannot respond to all engine demands by the driver.
• two combustion modes can be used, both characterized by the injection of fuel into the chamber during the intake phase.
• the richness of the mixture is equal to 1.
• This mode is necessary for high demands on engine torque, demands requiring high fuel flow rates.
• a rich homogeneous mode is also defined for the full load of the motor. This mode will not be mentioned here because it is not specific and can be assimilated to the homogeneous stoichiometric mode for the aspects treated.
• the preferred combustion mode to optimize consumption can be shown diagrammatically by the graph of the engine torque as a function of the engine rotation speed shown in FIG. 1.
• the engine control unit calculates the air, fuel and ignition advance commands to comply at all times with the torque setpoint.
• This "torque" command ensures a torque equal to the driver's request, including during mode changes.
• the quality of the monitoring of the torque setpoint is dependent on the dispersions that can cause the aging of the engine components, the dispersions during manufacturing or even the variable characteristics of commercial fuels.
• Pollutant emissions from the engine are treated by a catalytic system integrated into the exhaust.
• This system can be composed of one or more elements intended to oxidize or reduce the toxic components of the exhaust gases.
• the most dangerous components are unburnt hydrocarbons (Hc), carbon monoxide (CO) and nitrogen oxides (NOx).
• this catalyst Associated with a fine regulation of the richness of the air-fuel mixture making it possible to cause small amplitude fluctuations of the richness around 1, this catalyst allows an excellent overall conversion of the two pollutants.
• the invention aims to create a method and a device for overall management of the constraints linked to the choice of combustion mode.
• the constraints taken into account are the fuel consumption, the driving pleasure of the vehicle and the efficiency of treatment of pollutants during the rise in temperature after starting the engine.
• the subject of the invention is therefore a method of controlling the combustion mode of a four-stroke petrol engine with positive ignition equipped with a system for direct injection of fuel into the combustion chamber, of at least one catalyst.
• a control system receiving information relating to the rotation speed and the engine load, the position of the accelerator pedal, and the engine and gas temperatures d '' exhaust, characterized in that an estimate is made of the combustion efficiency of the different modes available and taking into account said information relating to the rotation speed and the engine load, the position of the accelerator pedal and the temperatures of the engine and exhaust gases, the choice of a priority combustion mode is controlled on the basis of said estimation of the combustion efficiency of the different modes available.
• the invention also relates to a device for controlling the combustion mode of a four-stroke gasoline engine with controlled ignition equipped with a system for direct injection of fuel into the combustion chamber, at least a catalyst placed in the engine exhaust line and a control system receiving sensors, information relating to the rotation speed and the engine load, the position of the accelerator pedal and the engine temperatures and exhaust gases, for the implementation of the process defined above, characterized in that the control system comprises means for controlling the choice of a priority combustion mode taking account of said information and from '' an estimate of the combustion efficiency of the various modes available. According to other characteristics:
• the device includes a control algorithm making it possible to calculate the combustion efficiency taking into account the thermal state of the combustion chamber, - the control algorithm makes it possible to correct the priority combustion mode using a switching efficiency allowing to anticipate driver behavior and thus to avoid inadvertent combustion mode changes on stealthy change of priority combustion mode,
• control algorithm makes it possible to anticipate the driver's behavior based on the combined analysis of the engine torque setpoints before and after application of the filters intended to soften the torque transitions to ensure good driving pleasure .
• control algorithm makes it possible to correct the combustion mode by taking into account the processing efficiency of said at least one catalytic element of the exhaust line during the rise in temperature after starting the engine.
• a priority combustion mode is defined by the minimum consumption criterion.
• the performance of a combustion mode is expressed in the form of a combustion efficiency and the combustion mode ensuring the best efficiency is chosen as the priority mode,
• the control unit tests the stability over time of the new mode.
• the objective of this test is to detect stealth changes that should not be applied, otherwise the user will experience sensitive torque. Stealth changes are detected by anticipating driver behavior.
• the engine control unit evaluates the efficiency of treatment of pollutants by the catalysis system.
• This estimate of the efficiency allows the control unit to impose, during the rise in temperature, the combustion mode guaranteeing the lowest level of pollutant emission. Once the nominal operating temperature is reached, this constraint fades and the priority combustion mode is authorized.
• - Fig.1 is a graph of the engine torque as a function of the speed motor rotation
• - Fig.2 is a block diagram of a device for controlling the combustion mode of an internal combustion engine according to the invention
• Fig.3 is a flowchart of the development of the combustion mode
• Fig.4 is a graph as a function of time of the combustion mode
• - Fig.5 is a flowchart of the E-Commute calculation algorithm
• - Fig.6 is a graphical representation of the stealth change of the priority combustion mode
• - Fig.7 is a graphic representation of the confirmed change in priority combustion mode on E-Commut
• - Fig.8 is a graphical representation of the confirmed change in priority combustion mode on strong acceleration of the driver; - Fig.9 shows an example of behavior of the different processing efficiencies of the exhaust line; and
• FIG. 2 represents an internal combustion engine 1, for example a four-stroke engine, with spark ignition gasoline, provided with a high pressure fuel supply system 2 injecting the fuel directly into the chamber combustion engine, a catalyst 3 placed in the exhaust line 4 and a control system 5 connected to a sensor 6 of the engine speed and load speed, to a sensor 7 of the accelerator pedal position 8 , to an engine temperature sensor 9 and to an exhaust gas temperature sensor 10.
• an internal combustion engine for example a four-stroke engine, with spark ignition gasoline, provided with a high pressure fuel supply system 2 injecting the fuel directly into the chamber combustion engine, a catalyst 3 placed in the exhaust line 4 and a control system 5 connected to a sensor 6 of the engine speed and load speed, to a sensor 7 of the accelerator pedal position 8 , to an engine temperature sensor 9 and to an exhaust gas temperature sensor 10.
• the combustion efficiency is evaluated and the priority combustion mode is established.
• step 12 the efficiency of switching between modes is evaluated.
• step 13 the mode transitions are managed from the data received from steps 11 and 12.
• the processing efficiency of the exhaust system is evaluated.
• the pollution control constraint is taken into account and information on the final combustion mode is delivered.
• the combustion efficiency E-Comb is defined as follows specific consumption of the engine in combustion mode i
• E-Comb; ; Lowest specific engine consumption for the operating point
• E-Comb 1 for the combustion mode ensuring the lowest specific consumption.
• the efficiency in mode i is configured from the static characterization performed on the bench. It is a function: there
• Chamber temperature Thermal state of the combustion chamber. Chamber temperature is initialized to the engine water temperature before starting the engine.
• T ° chamber tends to a value T ° chamber stabilized
• T 0 sta ilis cha mbre é F (Speed, Torque) x Ki F being the fundamental characteristic of the engine. It is estimated by calculation and corresponds to the nominal conditions in operation at 20 ° ambient in homogeneous combustion mode with a richness equal to 1.
• Ki is a degradation coefficient allowing to model the decrease in combustion temperatures in lean mixture (homogeneous or laminate).
• T ° chamber The filtering of T ° chamber is intended to reach T ° stabilized chamber II is a function of the engine water temperature.
• the filter used makes it possible to model the thermal inertia of all the parts making up the combustion chamber.
• the priority combustion mode is that which ensures the best combustion efficiency.
• the E-Commut switching efficiency is calculated.
• the switching efficiency only occurs when the priority combustion mode is changed.
• the objective of the efficiency calculation is to avoid repeated mode changes for small variations in the torque requested by the driver in a limit zone of operation between two modes.
• the initial combustion mode is 1.
• the driver increases its torque demand and E-Comb z becomes greater than E-Comb., (The same principle can be applied for any variation of the priority combustion mode).
• combustion mode 1 is capable of supplying the requested torque (without ensuring, by definition, the best consumption).
• the engine control system 5 scans for variations in the driver's room.
• step 20 for waiting for a calculation step.
• E-Commut 0 on the first calculation after crossing C12 and we go to test step 24 to determine if Cbrut> C12 + DC1.
• E-Commut 0 and we return to step 21 of testing E-Commut.
• E-Commut Ecommut + ⁇ .
• FIG. 6 represents a stealthy change in the priority combustion mode, which the strategy described makes it possible to avoid.
• the graph in FIG. 6 represents the values of the couples as a function of time.
• the curve (a) in solid lines shows the evolution over time of the value of Cfiltré.
• the dashed curve (ai) shows the corresponding evolution of Cbrut.
• the line (a2) parallel to the time axis represents C12.
• the line (a3) parallel to the time axis represents DC1 + C12.
• the curve (b) extending in step on either side of the time axis, represents the value of Cbrut (n) - Cbrut (n-I).
• Curve (c) represents the variation of E-Commut.
• the curve (a) in solid lines represents Cfiltré
• the curve (ai) in dotted lines represents Cbrut.
• Curve (b) represents Cbrut (n) - Cbrut (n-1).
• Curve (c) represents E-Commut. We see from this curve that combustion mode 2 is applied when E-Commut reaches 1.
• FIG. 8 represents the confirmed change in the priority combustion mode on strong acceleration of the driver.
• Curve (a) in solid lines represents the change in the value of Cfiltré.
• Curves a2 and a3 represent the constant values of C12 and DCL.
• Curve (b) represents Cbrut (n) - Cbrut (n-1).
• Curve (c) represents E-Commut.
• Mode 2 is applied when Cbrut reaches the value of DC1.
• E-Ech R ⁇ 1 Nox l (T °,) Efficiency of treatment of Nox with richness ⁇ 1 by element i
• E-Ech R ⁇ 1 Hc , (T °,) Efficiency of treatment of hydrocarbons with richness ⁇ 1 by element i.
• E-Ech R ⁇ 1 HC Sup (E-Ech R ⁇ 1 ⁇ HC ⁇ l )
• E-Ech R ⁇ 1 Nox Sup (E-Ech R ⁇ 1 Nox ,)
• E-Ech R ⁇ 1 Inf (E-Ech R ⁇ 1 ⁇ Hc ; E-Ech R ⁇ 1 ⁇ Nox )
• FIG. 9a represents the behavior of the treatment efficiency of the exhaust system with two elements, HC and NOX for a mixture of richness equal to 1.
• FIG. 9b represents the behavior of the processing efficiency of the two-element exhaust line for a lean mixture.
• FIG. 9c represents the synthesis of the treatment efficiency behaviors represented in FIGS. 9a and 9b.
• the treatment efficiency is further modified when the efficiency of the catalytic treatment is taken into account.
• the priority combustion mode is only authorized if the overall efficiency of the exhaust system for the richness associated with the treatment mode is sufficient to avoid the emission of pollutants to the atmosphere. If no efficiency is sufficient to authorize the priority combustion mode, a combustion mode specific to pollution control is imposed.
• This mode depends on the characteristics of the engine.
• the graph in FIG. 10 represents the treatment efficiency behavior of the exhaust line taking into account the catalytic treatment efficiency.
• the graph is delimited in three regions I, II, III, separated by vertical dotted lines intersecting the temperature axis.
• any priority mode of combustion cannot be applied.
• a specific combustion mode intended to rapidly increase the temperature of the exhaust system is imposed.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Exhaust Gas After Treatment (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
• Control Of Vehicle Engines Or Engines For Specific Uses (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)

Applications Claiming Priority (3)

Publications (2)

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Family Cites Families (11)

• 1999
  • 1999-07-23 FR FR9909617A patent/FR2796670B1/fr not_active Expired - Fee Related
• 2000
  • 2000-06-05 JP JP2001512172A patent/JP4527919B2/ja not_active Expired - Fee Related
  • 2000-06-05 WO PCT/FR2000/001539 patent/WO2001007769A1/fr active IP Right Grant
  • 2000-06-05 ES ES00938888T patent/ES2216903T3/es not_active Expired - Lifetime
  • 2000-06-05 AT AT00938888T patent/ATE264996T1/de not_active IP Right Cessation
  • 2000-06-05 EP EP00938888A patent/EP1115965B1/de not_active Expired - Lifetime
  • 2000-06-05 DE DE60010031T patent/DE60010031T2/de not_active Expired - Lifetime
  • 2000-06-05 US US09/763,550 patent/US6584952B1/en not_active Expired - Lifetime

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