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
  • F02D17/00—Controlling engines by cutting out individual cylinders; Rendering engines inoperative or idling
  • F02D17/02—Cutting-out
• • 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
  • F02D2250/21—Control of the engine output torque during a transition between engine operation modes or states
• • 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
  • F02P5/145—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions using electrical means
  • F02P5/15—Digital data processing
  • F02P5/1502—Digital data processing using one central computing unit

Definitions

• the invention lies in the technical field of controlling the combustion of a motor vehicle engine, including spark ignition, and more specifically the strategy to build the selective injection cut cylinder.
• This strategy firstly monitors the torque attainable by the heat engine and requests the cut-off, respectively the delivery, of injection of one or more cylinders when the engine is no longer able to follow a torque setpoint that has become too low, respectively too high. case of delivery of a cylinder.
• an ESP request for "Electronic Stability Program” in English or Electro-Stabilizer Scheduled
• a request for approval for example
• the torque setpoint received by the engine can become so low that the engine can no longer meet it.
• the motor control uses different levers.
• the degradation of the ignition advance decreases the efficiency of the engine and therefore the torque produced.
• This lever is used for bright transient phases because it has a fast dynamic.
• the solution is to minimize the engine air supply, by closing the butterfly for example.
• This lever has a rather slow dynamic due to the control of the actuators, the throttle body in this case, and because of the dynamics of the air.
• the lever on the air branch alone can only be used with difficulty, especially during an action such as a gearshift on automatic gearbox, because its potential to torque degradation is high, but its momentum is weak. This has the impact of having a poor follow-up of the couple and a quality of change of report degraded, even a bad feeling for the customer.
• the degradation of ignition advances offers a rather low potential on the torque, but a very high dynamic and here too, torque tracking is not always ensured, with the impacts seen above.
• the other disadvantage of this lever is that it greatly degrades the efficiency of the engine which generates high thermal stresses such as an increase in the temperature at the exhaust, with risk of breakage.
• the cylinder injection cutoff thus offers a high potential.
• the engine control must ideally ensure in advance that the torque setpoint requested by the torque structure will be reached by engine. Therefore, the challenge is to put in place a strategy to request the injection cut of one or more cylinders with the advantage of improving the torque tracking by a better torque potential achievable and a dynamic equivalent to that branch advance. Also this strategy has the effect of reducing the gas flow output of the engine and thus to control the temperature at the exhaust.
• the object of the present invention is to provide an engine in which the deactivations and reactivations of cylinders are effected effectively on torque reference tracking.
• a control method of a motor vehicle combustion engine having a plurality of combustion cylinders comprising the step of reducing the number of active cylinders in case torque setpoint reduction method, comprising a step of evaluating whether the torque setpoint is lower than a threshold torque distinct from the minimum torque attainable with the number of active cylinders present and distinct from the maximum torque achievable with an active cylinder minus , the threshold torque being between these two pairs respectively minimum and maximum and the step of reducing the number of active cylinders in the affirmative of this evaluation.
• thermodynamic conditions pressure / temperature
• the thermodynamic conditions are such that there is a risk for the components of the combustion chamber and the exhaust line (premature wear of parts, even breakage), here we speak of maximum advance.
• the minimum torque is the torque achieved by the motor with a given air flow, if the minimum advance is applied
• - and the maximum torque is the torque achieved by the motor with a given air flow, if the maximum advance is applied.
• the maximum achievable torque with a less active cylinder is less than the minimum torque achievable with the current number of active cylinders.
• the strategy requires the cutoff (respectively the reset) when the setpoint torque is lower (respectively greater) than the minimum (respectively maximum) torque.
• the strategy according to the invention makes it possible to make different types of cutoff / reset: - either cut off as soon as the target torque is lower than the minimum torque, and in this case case achieve a torque lower than the requested torque; - Or cut as soon as the setpoint torque is lower than the maximum torque (that would realize the engine if a cylinder was cut) and in this case, achieve a higher torque, before respecting the target torque; - Or cut as soon as the target torque is less than a "virtual" torque, which is a calibrated intermediate between the minimum torque and the maximum torque with one cylinder less.
• the method comprises the step of evaluating whether the torque setpoint is lower than the minimum torque achievable with the current number of active cylinders and performing the step of evaluating whether the torque setpoint is lower than the torque threshold in the case where the torque setpoint is lower than the minimum achievable torque with the current number of active cylinders.
• the method comprises the step of calculating different torque paths, including a path consisting in deactivating a cylinder when crossing said threshold torque and opting for one of these different paths as a function of a preset parameter of torque tracking.
• one of the different calculated paths comprises a section preceding a cylinder deactivation in which section the torque remains greater than the torque setpoint.
• one of the different calculated paths is to deactivate a cylinder when the torque setpoint becomes lower than the maximum torque achievable with a cylinder active less.
• one of the different calculated paths comprises a section following a cylinder deactivation in which the torque section is less than the torque setpoint.
• one of the different paths is to deactivate a cylinder as soon as the torque setpoint becomes lower than the minimum torque achievable with the current number of active cylinders.
• the invention also relates to a motor vehicle combustion engine control module comprising a plurality of combustion cylinders, the control module being configured to reduce the number of active cylinders in case of torque setback, characterized in that it is configured to evaluate whether the torque setpoint is lower than a threshold torque that is distinct from the minimum torque attainable with the number of active cylinders present and distinct from the maximum torque attainable with one less active cylinder, the threshold torque being included between these two pairs respectively minimum and maximum and the control module is configured to reduce the number of active cylinders in the affirmative of this evaluation.
• the invention also relates to a motor vehicle comprising a combustion engine and such a control module of the combustion engine.
• the torque setpoint becomes very low to the point of being less than the minimum torque achievable with four cylinders.
• the strategy then requires the injection cut of a cylinder. If thereafter the torque setpoint always decreases, another cylinder can be cut, until reaching the limit of number of cylinders allowed to be cut. Conversely, when the torque increases sufficiently to exceed the minimum torque achievable with 1 + n cylinders, not being the number of cylinders injecting at the instant considered, the strategy requires the surrender injection of a cylinder.
• Zone 2 represents a zone of achievable torque values with a number of four cylinders, this zone 2 having a low limit 3 corresponding to the minimum torque value accessible with four active cylinders.
• An area 4 represents the accessible torque zone with three active cylinders, the zone 4 having an upper limit 5 consisting of the maximum torque value achievable with three active cylinders.
• the horizontal band 6 situated between zones 2 and 4 consists of a band of torque values which are not accessible with four cylinders or with three cylinders, this band consisting of a dead zone as defined above.
• the present strategy proposes different paths for the effective torque, among which the motor control will choose according to the type of desired torque tracking.
• the injection cutoff is requested when the motor can no longer follow the torque setpoint with the current roll number.
• the deactivation of the cylinder is represented in the form of a vertical arrow 10 which originates at the point where the torque setpoint reaches the lower limit 3 of zone 2 achievable with four cylinders.
• the torque setpoint 1 is underestimated as illustrated by the horizontal arrow 1 1 as the torque setpoint has not reached the torque zone 4 achievable with one cylinder less.
• the injection cutoff is requested when the torque setpoint 1 reaches the maximum achievable torque 5 with one less cylinder.
• the torque setpoint is overestimated according to the horizontal arrow 20 during the time interval when the torque setpoint 1 is in the dead zone 6, that is to say during the time interval where the Torque reference 1 has not yet reached the torque zone 4 achievable with one less cylinder, here with three cylinders.
• the deactivation of a cylinder is controlled and the cylinder is deactivated according to the vertical arrow 21.
• the injection cutoff is requested when the engine torque setpoint 1 reaches a torque Ts which is calibrated between the minimum torque 3 achievable with the number of active cylinders current and the maximum torque 5 achievable with the number of active cylinders decreased by one cylinder, here with three active cylinders.
• Ts a torque which is calibrated between the minimum torque 3 achievable with the number of active cylinders current and the maximum torque 5 achievable with the number of active cylinders decreased by one cylinder, here with three active cylinders.
• the torque setpoint is optimally monitored.
• the strategy measures the difference between the minimum torque with the number of cylinders running and the maximum torque with the current cylinder number decreased by one cylinder.
• the calibrated torque threshold from which the deactivation of a cylinder is requested is a percentage of the dead zone. A percentage at 100% is equivalent to the first path described above, a percentage at 0% is equivalent to the second path described above.
• the present strategy proposes different paths depending on the type of desired torque tracking.
• a first path the injection delivery is requested when the engine can no longer follow the torque setpoint with the number of cylinders running. In this case, the torque setpoint is overestimated until it reaches the achievable torque zone with one more cylinder.
• the injection delivery is requested when the torque setpoint reaches the achievable torque with one more cylinder. In this case, the torque setpoint is underestimated until it reaches the achievable torque zone with one more cylinder.
• the injection reset is requested when the engine torque setpoint reaches a calibrated torque between the minimum torque with the number of active cylinders added with a cylinder and the maximum torque achievable with the number of cylinders. active cylinders current.
• the torque setpoint is optimally monitored.
• the strategy measures the difference between the minimum achievable torque with one more active cylinder and the maximum achievable torque with the number of active cylinders running.
• the calibratable threshold is a percentage of the dead zone. A percentage of 0% is equivalent to the first path described above, a percentage of 100% is equivalent to the second path described above.
• the present device therefore requires the selective deactivation of injection on one or more cylinders when the torque setpoint requested to the motor on the branch advance or the air branch can not be followed, respectively, in the case of a reactivation when the torque setpoint requested from the motor can be realized with one more cylinder. For this it calculates in real time the achievable torque once a deactivated cylinder or once a reactivated cylinder to request the deactivation or activation according to several "paths" calibrated according to the type of desired torque tracking.
• the desired type of torque tracking which generates the implementation of one or the other of the elaborated paths, is for example a choice of driving comfort level, chosen by the driver at the dashboard or chosen at the factory .
• the type of monitoring can alternatively be conditioned by the fact that the vehicle is driven in the city or highway, on the basis of a detection of more or less high variations of the speed of the vehicle.
• engine control develops a single path such as the third calibrated trigger path of the deactivation and / or reactivation of cylinder, thereby allowing improved control of the deactivation and / or reactivation.
• the device described here is particularly advantageous when the motor torque setpoint is in a so-called "dead" motor torque zone, that is to say where the desired torque evolution can not be achieved.
• Such a device does not improve the intrinsic performance of the engine, the torque areas covering or not are defined by the physics of the engine such as the displacement and the combustion technologies used and the choice of calibrations. However, once these parameters have been defined, such a device, and in particular the path with deactivation and / or reactivation calibration, makes it possible to offer a significant gain in the torque control by artificially varying the torque zones that can be reached by the motor.
• the strategy makes it possible to follow as closely as possible the torque setpoint in delicate life situations such as automatic gearbox ratio changes or ESP activations using to the maximum the potential of the selective disconnection of the gearbox. cylinder.
• the proposed strategy makes it possible to improve torque monitoring by the engine during very dynamic life situations that may be critical for the engine itself and the consumer systems such as the automatic gearbox or the ESP actuators, with for impact a bad feeling by the customer, even a risk for his safety.
• this strategy provides a gain in torque tracking by allowing high dynamics combined with high torque reduction potential. It also brings a gain in terms of protection of the engine because the degradation of advance ignition is less and as the injection is cut on one or more cylinders, the exhaust gas flow is lower, which decreases the exhaust gas temperature.
• the monitoring of the achievable torque also makes it possible to avoid situations of sloshing of the injection cut-off set point because the system is found in a dead zone of torque.
• Such a strategy can be implemented without additional high cost because it can be implemented in the motor control alone, without the need for sensor and / or additional actuator.
• This type of strategy is particularly advantageous on heavily loaded small displacement engines and sometimes with little cylinders because their torque reduction potential is quite low by the only degradation of the ignition advance compared to a thermal engine with a lot of cylinders and a high cylinder capacity.

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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)
• Combined Controls Of Internal Combustion Engines (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=52021275

Family Applications (1)

Country Status (4)

Families Citing this family (1)

Family Cites Families (8)

• 2014
  • 2014-10-13 FR FR1459793A patent/FR3027063B1/fr active Active
• 2015
  • 2015-09-14 CN CN201580055181.0A patent/CN106795822B/zh active Active
  • 2015-09-14 EP EP15771209.2A patent/EP3207237A1/de not_active Withdrawn
  • 2015-09-14 WO PCT/FR2015/052450 patent/WO2016059312A1/fr not_active Ceased

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