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
  • F02D41/008—Controlling each cylinder individually
  • F02D41/0087—Selective cylinder activation, i.e. partial cylinder operation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D37/00—Non-electrical conjoint control of two or more functions of engines, not otherwise provided for
  • F02D37/02—Non-electrical conjoint control of two or more functions of engines, not otherwise provided for one of the functions being ignition
• • 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
  • F02D41/123—Introducing corrections for particular operating conditions for deceleration the fuel injection being cut-off
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P5/00—Advancing or retarding ignition; Control therefor
  • F02P5/04—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions
  • F02P5/045—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions combined with electronic control of other engine functions, e.g. fuel injection
• • 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
  • F02D2200/1002—Output torque
• • 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
  • F02D2250/00—Engine control related to specific problems or objectives
  • F02D2250/18—Control of the engine output torque
  • F02D2250/22—Control of the engine output torque by keeping a torque reserve, i.e. with temporarily reduced drive train or engine efficiency

Definitions

• the invention relates to a selective cutting process of the injection of one or more cylinders of a heat engine and the corresponding motor vehicle.
• the invention applies to the field of control control of motor vehicles equipped with a thermal ignition propulsion unit (GMP) spark ignition with a manual gearbox (BVM), automated (BVA), piloted (BVMP) or double clutch (DCT).
• GMP thermal ignition propulsion unit
• BVM manual gearbox
• BVA automated
• BVMP piloted
• DCT double clutch
• a vehicle equipped with a thermal spark-ignition engine operating, for example, with petrol, is in a manner known per se equipped with a supervisor making it possible to choose the operating points of the vehicle components, in particular the engine, in order to respect the will of the driver in terms of requested torque.
• the ignition advance (AA) defines the angle of rotation that separates the spark instant from the top dead center.
• the ignition advance is adapted according to the engine parameters.
• the ignition timing is limited by engine constraints.
• the advance is too important, the spark occurs too early, the propagation of the flame front is slower because the density of the fuel is insufficient. Combustion is not complete when the top dead center is passed, so that the unburned fuel portion reaches its self-ignition threshold at the time of compression along the walls, causing the pinging phenomenon.
• the engine does not operate optimally and its acceleration is low. Contrary to rattling, it is necessary to limit the ignition advance by a minimum limit in order to avoid misfires as well as the breakage of mechanical elements such as the exhaust or catalyst. Such a limitation of the ignition advance thus guarantees the ignition of the mixture.
• the torque achieved by the engine to meet the torque desired by the driver depends on the amount of fuel injected, the amount of air in the combustion chamber, and the ignition time to trigger combustion. For a given amount of air and for a quantity of injected fuel, the torque profile achieved by the engine is found as a function of the ignition advance shown in FIG. 1. Thus at iso consumption (in air and fuel), the engine will provide maximum torque on its optimal advance, so that its performance will be maximum.
• a change strategy of the ignition advance which has the advantage of having an instant impact on the engine torque and therefore a very fast dynamics.
• such a strategy presents a very slow dynamic. We therefore generally choose to follow a sudden change in the driver's will by changing the ignition timing due to the slow dynamics of the air loop.
• the invention aims to effectively overcome these disadvantages by providing a method of managing an engine torque by selectively cutting the injection of one or more cylinders of a spark ignition engine, characterized in that it comprises the step of determining a maximum number of cylinders whose injection is allowed to be cut, and as soon as at least one safety problem is detected among: reaching a limit of advance to the injection , a fault injection, or a malfunction of a dual flywheel, the method further comprises the step of making a cut of the injection of a cylinder, this step of cutting the injection of a cylinders being capable of being repeated within the limit of the maximum number of cylinders whose injection is allowed to be cut.
• the invention thus improves the driving pleasure and the performance of the vehicle especially during the phases of very low torque setpoints.
• an optimization of the number of cylinders used to generate the requested torque reduces the consumption, the fuel injection into the non-useful cylinders being saved.
• the fact of cutting the injection on some cylinders makes it possible to overcome the problems related to mechanical malfunctions or problems related to the limits of the engine control, such as rattling, or the follow-up of low setpoints of torque.
• the method comprises the step of reducing the ignition advance until reaching the limit of 'advance ignition and then increase the ignition advance after the injection of a cylinder has been cut so as to compensate for a loss of torque due to the cutting of the injection of said cylinder and then decrease of again the ignition advance up to the ignition advance limit.
• the maximum number of cylinders whose injection is allowed to be cut is determined according to the torque requirements of a vehicle approval module, a brake control module d emergency and a gearbox management module.
• the driving pleasure module determines in relation established a first number of cylinders whose injection is allowed to be cut according to a engine speed and a maximum torque achievable by the engine,
• the emergency braking management module determines by calibration a second number of cylinders whose injection is allowed to be cut according to the load and the engine speed,
• the gearbox management module determines by calibration a third number of cylinders whose injection is allowed to be cut in gear ratio and speed control of the engine,
• the maximum number of cylinders whose injection is allowed to be cut is determined from the number of cylinders provided by the different modules according to an order of priority assigned to these different modules. According to one embodiment, the maximum number of cylinders whose injection is allowed to be cut is limited to the number of cylinders of the engine minus one.
• the order of priority is assigned in ascending order to the driving approval module, the emergency brake management module and the transmission management module.
• the cut-off of the injection of one of the cylinders is authorized if the following cut-off criteria are verified:
• a motor speed is greater than a threshold value
• a setpoint torque is less than a threshold value
• the threshold value of the engine speed is of the order of 1500 revolutions / min.
• the threshold value of the target torque is of the order of 30 N.m.
• the invention also relates to a motor vehicle equipped with a motor computer implementing the method according to the invention.
• Figure 1 already described, shows a graphical representation of the torque produced by the engine as a function of the ignition advance
• FIG. 2 shows a schematic representation of the modules of a torque control management system of a heat engine according to the invention
• Figure 3 shows a schematic representation of the modules ensuring the determination of the maximum number of cylinders whose injection is allowed to be cut;
• FIG. 4 shows a diagram of the evolution as a function of time of various engine parameters including the activation state of the cylinders during the implementation of the method according to the invention during a follow-up of a set torque.
• Identical elements, similar, or the like retain the same reference from one figure to another.
• FIG. 2 shows a system 1 for managing the torque control of a spark ignition engine integrated in a motor ECU.
• This system 1 comprises a module 2 for interpreting the will of the driver.
• This module 2 is able to determine the setpoint torque Ce from the engine speed Wm, a gear ratio R engaged, and a position P of the accelerator pedal actuated by the driver to retranscribe the the driver's desire for acceleration.
• An approval module 3 provides a filtering of the set torque Ce to limit the jolts felt. This module 3 thus ensures the management of the vehicle in pairs as a function of the needs relating to the optimization of the approval, the level of the feeling, the typing of the desired vehicle, and the monitoring of the torque setpoint.
• the couple Cf engine losses is the torque needed by the engine to advance the vehicle including taking into account engine friction and losses related to accessories, such as the alternator.
• a module 4 manages the emergency braking torque requirements to ensure in particular the anti-skid of the vehicle.
• a module 5 manages the torque requirements related to the limitations of the vehicle gearbox.
• a module 6 provides the management of the selective cutting of the rolls, that is to say an injection cut on a number of engine cylinders from information relating to the number of cylinders whose injection is allowed to be cut from the various modules 3 to 5. More specifically, the driving pleasure module 3 determines a number N1 of cylinders whose injection is allowed to be cut in relation established according to the engine speed Wm and a maximum torque Cmax achievable by the engine.
• the emergency brake management module 4 determines by calibration a number N2 of cylinders whose injection is allowed to be cut according to the engine load Ch and the engine speed Wm. Indeed, the more the engine is loaded, less it will be possible to cut cylinders in order to achieve this load. It will not be possible to ask for a heavy load on a single cylinder for example.
• the module 5 management of the gearbox determines by calibration the number N3 of cylinders whose injection is allowed to be cut in gear ratio and speed regulation.
• the module 6 then provides, via a module 6.1, the synthesis of the selective cut-off requests according to a priority level assigned to the modules 3-5 to determine a number N 'of cylinders whose injection is allowed to be cut. If necessary, this number N 'can be limited by the module 6.2 to determine a number Nmax of cylinders whose injection is allowed to be cut equal to the maximum number of cylinders of the engine minus one. Indeed, at least one cylinder must be in operating condition otherwise the engine is stopped and the cut is then more selective but total.
• an increasing order of priority is assigned to the driver approval module 3, to the emergency brake management module 4, and to the module 5 for managing the gearbox.
• the driver approval module 3 authorizes the cutting of the injection of two cylinders while the management module 5 the gearbox allows the cutting of the injection of a single cylinder, then only the injection cut of a single cylinder will be allowed. Thanks to this strategy, it is possible to manage the life situations of the vehicle requiring the cutting of the injection as well as the number of cylinders to be cut without the risk of degrading mechanical elements or the behavior of the vehicle with respect to braking. urgency or driving pleasure.
• the module 6 emits a signal corresponding to the maximum number of cylinders Nmax whose injection is allowed to be cut to an injection management module 7 belonging to the engine stratum (see Figure 2).
• the module 6 also ensures the issuance of a second signal SA corresponding to the management of the activation and deactivation of the cylinder injection cuts according to the requirements of tracking instructions and the needs related to security .
• Priority is given to safety needs, the goal being to protect the operation of the engine and the vehicle and its occupants.
• the selective cutting of one or more cylinders is activated during the detection of safety problems in order to avoid damaging elements of the power train.
• These security problems may consist of the occurrence of the phenomenon of rattling, a malfunction of a double damping flywheel associated with the crankshaft, or an injection fault.
• An injection fault will for example be detected by the engine computer when a motor torque corresponding to a quantity of fuel yet sent to the injectors is not made by the engine. In this case, it is planned to cut the cylinder whose injection has failed.
• the malfunction of the double damping flywheel is detected when it is activated, the double damping flywheel can not compensate for oscillations of the engine speed.
• the engine speed Wm is greater than a threshold value V1, for example of the order 1500 rpm, since at low speed it is necessary to provide torque to ensure the idling of the vehicle,
• the setpoint torque is lower than a threshold value V2, for example of the order of 30N.m, and
• deactivating the selective breaking of a cylinder is performed according to the evolution of the set torque Ce and therefore the evolution of the will of the driver via the pedal. Indeed, if the setpoint torque Ce increases, then it is no longer necessary to cut the injection of cylinders.
• the deactivation of the selective breaking is performed as a function of the changing torque requirements of the module 4 for emergency braking management and the module 5 for managing the gearbox.
• FIG. of deposit Ce shows the changes as a function of time, the setpoint torque Ce, the engine torque realized Cm, the ignition advance AA, and the activation state of the cylinders in the lower part of the diagram (the number on the ordinate indicates the number of cylinders whose injection has been cut off). It has also been shown in broken lines the minimum engine torque CAAmin can be reached corresponding to a minimum limit AAmin of the ignition advance.
• the maximum number Nmax of cylinders whose injection can be cut is equal to three for a vehicle comprising a four-cylinder heat engine.
• the setpoint torque Ce decreases while the previously defined cutoff criteria are met. So that the engine torque Cm achieves the target torque Ce, the ignition advance AA decreases to reach its minimum limit AAmin. The engine torque Cm then decreases to the CAAmin torque that can be reached by changing the ignition timing.
• the minimum ignition advance limit AAmin is defined by the motor constraints and therefore can not be changed.
• the injection of a cylinder is cut off to reduce the minimum achievable engine torque CAAmin. This minimal torque reduction makes it possible to increase the ignition advance. Indeed, this increase in ignition advance AA is such that it makes it possible to compensate for the loss of torque and thus the fall of the nominal efficiency ncons following the cut-off of the injection of the cylinder.
• the ignition advance AA can then decrease again until reaching once again its minimum terminal AAmin.
• these steps are repeated as many times as there are cylinders whose injection is allowed to be cut. The more one will cut the injection of cylinders, the more the realized torque Cm may be low.
• the maximum number Nmax of cylinders whose injection is allowed to be cut is reached. Since the setpoint torque Ce is greater than the minimum torque that can be achieved CAAmin in a configuration of operation of the engine with a cylinder, the engine torque Cm can still follow the torque setpoint Ce.
• phase P3 the setpoint torque Ce continues to decrease below the CAAmin torque. However, it is no longer possible to follow the setpoint torque Ce since it is not possible to cut the injection of an additional cylinder and the ignition advance AA is limited by its terminal. minimum AAmin. The yield is falling. This life situation is dangerous insofar as the catalyst deteriorates if the ignition advance AA is maintained for a long time to a minimum. As soon as the torque setpoint Ce returns above the attainable minimum CAAmin, the engine torque Cm can then follow again the setpoint torque Ce so that the efficiency ncons increases.
• phase P4 unlike the phase P1, when the set torque Ce increases, it allows again the injection into the cylinders whose injection was previously cut. After each activation, the torque CAAmin corresponding to the minimum ignition advance limit increases, so that it is possible to reduce the ignition advance AA to compensate for the increase in torque and thus the fall of the ignition. setpoint efficiency due to the additional cylinder. It is then possible to progressively increase the ignition advance AA to follow the torque set point Ce until the new CAAmin torque can be achieved with an additional cylinder. When all the cylinders are activated, it will be possible to modify only the ignition advance AA to follow the increase of the set torque Ce.
• the skilled person may make changes to the parameters of the motor torque management method described above without departing from the scope of the invention.
• the module 4 for emergency braking management such as an ESP system (acronym for "Electronic Stability Program")
• the maximum number of cylinders Nmax whose injection is allowed to be cut is determined only from the values returned by module 2 driving pleasure and the gearbox management module 5.
• the threshold values V1 and V2 can be adapted according to the application.

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

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Citations (4)

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• 2012
  • 2012-12-04 FR FR1261586A patent/FR2998923B1/fr active Active
• 2013
  • 2013-11-20 CN CN201380063181.6A patent/CN104968919B/zh active Active
  • 2013-11-20 WO PCT/FR2013/052801 patent/WO2014087067A1/fr active Application Filing
  • 2013-11-20 EP EP13803158.8A patent/EP2929168B1/fr active Active

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