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
  • F02D41/0085—Balancing of cylinder outputs, e.g. speed, torque or air-fuel ratio
• • 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
  • F02D2041/1433—Introducing closed-loop corrections characterised by the control or regulation method using a model or simulation of the system
• • 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
  • F02D2200/1012—Engine speed gradient
• • 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
  • F02D2250/28—Control for reducing torsional vibrations, e.g. at acceleration
• • 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
  • F02D41/1497—With detection of the mechanical response of the engine
  • F02D41/1498—With detection of the mechanical response of the engine measuring engine roughness

Definitions

• the invention relates to the field of controlling the stability in operation of combustion engines.
• Spark ignition engines have, especially during their operation in partial load, a lower intake pressure at atmospheric pressure. This pressure below atmospheric pressure creates so-called pumping losses which lead to overconsumption of fuel, due to additional work imposed on the engine pistons during the intake phases.
• camshaft phase shifters to adapt the crossing of the intake and exhaust valves.
• the valve crossing is the particular result of an exhaust delay and an advance on admission. It has the effect of facilitating the aspiration of fresh gases with the flue gases which facilitates the filling of the cylinder.
• the crossing has an effect on the stability of the engine. It is important in the context of the control of the operation of spark ignition combustion engines to be able to characterize their operating stability. In particular, imposing a too large crossover valves can greatly degrade the engine stability, which is detrimental to both the comfort of the motorist, the proper operation of the engine, and its lifetime. For optimum engine performance, the stability of the engine must be taken into account.
• the crossing levels are calibrated so as to have a compromise between engine robustness and fuel consumption level. These settings are fixed in maps, which do not take into account the actual operation of the engine, and are therefore can precise, and do not achieve an optimal level of consumption, that is to say the weaker possible.
• the invention there is provided a control method in which the stability of a combustion engine is more precisely characterized, in particular during the transient operating phases (phases of variation of the rotational speed of the engine ).
• This method makes it possible to adapt the operating parameters of the engine having an influence on its stability such as the ignition advance or the richness, but is particularly advantageous for adapting the crossover valves and thus optimize fuel consumption.
• transient engine More specifically, the invention relates to a method of regulating an operating parameter of an internal combustion engine, comprising the following steps:
• the stability index is a function of the difference between the measured time derivative of the engine speed to the moment of calculation, and the estimated time derivative of the engine speed as a function of the engine torque and the inertia opposing the variation of its rotational speed. It is thus possible to regulate the parameters of the engine control having an influence on its stability, including the wealth, the ignition timing, and the crossing of the valves.
• the setpoint supplied may be used to increase the exhaust temperature, reduce the engine's pollutant emissions or reduce fuel consumption.
• the determination of an index representative of the combustion stability of the engine as a function of the difference between the time derivative of the engine speed measured and the time derivative of the estimated engine speed, that is to say such that it is expected that it is based in particular on the engine torque evaluated by the engine control system and the inertia opposing the variation of the rotational speed of the engine offers the advantage of allowing the obtaining a reliable index including in the transient engine operating phases.
• the engine control set tends to optimize the crossing of the valves to reduce the fuel consumption of the engine while respecting the stability guideline.
• the method according to the invention is particularly advantageous for regulating the crossing of the valves to reduce the engine consumption, especially in the operating phases of the engine at low and medium load.
• the optimization of the valve crossover consists in applying the opening instructions of the intake and exhaust valve closing valves to minimize the fuel consumption, by maximizing the crossing period during which the intake and exhaust valves are simultaneously open, and positioning these openings and closures in the engine cycle as well as possible.
• the method is applicable to the regulation of other parameters influencing the engine operating stability (ignition advance and richness), but this is not its preferential application, because there are other reliable and simpler methods for regulate: by construction of a stability index as known in the prior art for the stabilized phases, especially immediately after starting the engine, or by using specific probes during the transient phases.
• a backup strategy is implemented in case of stability deviation greater than a predetermined threshold.
• High engine instability can lead to engine failure.
• a backup strategy helps to ensure the reliability of the engine.
• Such a strategy consists in rapidly returning the engine to an operating point on which its stability is ensured, for example by applying a zero valve crossover, and conservative instructions for ignition advance and richness.
• the process steps are repeated with each combustion in the engine.
• a rapid regulation of the parameter in question is obtained, which makes it possible in particular to optimize this parameter by having at all times of the operation of the engine a stability index very close to the stability setpoint.
• the method is implemented during phases of transient operation of the engine. It can also be used during stabilized operation phases.
• the stability index is calculated by the formula
• Is is the stability index
• ⁇ ⁇ ⁇ 3 ⁇ 4Mewee is the measured time derivative of the dt
• ⁇ TMTM ⁇ is the engine speed measured at the instant of the computation
• T PMH is the time elapsed at the time of calculation since previous combustion.
• This calculation method makes it possible to obtain a dimensionless index representative of the operating stability of the engine, including in its phases of transient operation.
• the estimated time derivative of the engine speed is calculated by the formula: dco Estimée _ Couple _ Estime
• Couple_Estime is the estimate of the torque of the motor at
• T PMH is the time elapsed since previous combustion
• J eq uivait is the translation in the form of a moment of inertia equivalent of the inertia opposing the variation of the motor rotation speed. It is therefore the inertia of the engine or the vehicle brought back to the motor shaft according to the engaged gear ratio. Taking into account the inertia of the vehicle brought back to the motor shaft makes it possible to use the stability indicator in transient and moving vehicle
• the measured time derivative of the engine speed is determined by the formula: had) r ⁇ ⁇ ⁇ ⁇
• the invention also relates to a control system of an internal combustion engine, implementing the method according to one of the preceding claims.
• FIG. 1 is a general block diagram of the method according to the invention
• FIG. 2 represents an exemplary control strategy implemented by the method according to the invention.
• FIG. 3 represents a calculation module of the regulator of FIG. 1.
• Figure 1 describes, using block diagrams, the implementation of the method according to the invention.
• a supervisor 1 determines, for example according to the operating conditions of a motor 2, whether or not the method according to the invention is implemented.
• the stability of the engine 2 is determined by a calculation function of a stability indicator 3, which gives as a result a stability indicator Is.
• a calculator 4 supplies a stability setpoint Cs, for example by means of a map specific to the engine 2.
• a comparator 5 calculates the difference between the two values Cs and Is, to output a signal Es, called deviation or stability error.
• the stability deviation Es is then supplied to a regulator 6, in the example a P.I.D type regulator. (derivative integral proportional), but this can be of any other type (LQ, Hinfini, etc.).
• the regulator then takes into account the stability deviation Es to calculate a valve crossing setpoint, that is to say in practice an OA inlet opening setpoint and a valve closing setpoint.
• exhaust FE This setpoint is transmitted to the engine control member to be applied to the intake and exhaust phase shifters.
• the stability indicator must allow to quickly and reliably detect the combustion quality even in transient regime.
• combustion stability indicator uses in the invention 3 main input data:
• Stability is characterized in the invention by an index, a function of the difference between the derivative of the engine speed as measured (or more precisely, as calculated using engine speed measurements) with the estimated derivative. that the engine should have because of the engine torque at the time of calculation. This makes it possible to obtain a representative stability index even in the transient motor operating phases.
• the measured time derivative of the regime is calculated by the following formula dt T PMH in which - ⁇ ⁇ ⁇ (rad / s) is the engine speed at the moment of calculation, instant corresponding to the instant of a combustion;
• This calculation is preferably performed at each combustion of the engine.
• the regime is measured also with each combustion.
• the estimated time derivative of the regime is calculated by the following formula:
• Torque_Estimate (Nm) is the estimate of the motor torque, given by the motor control system, and Jequivait (kg.m 2 ) is the translation in the form of a moment of inertia equivalent of the inertia opposing the variation the speed of rotation of the engine. This is the inertia of the engine or the vehicle brought back to the motor shaft according to the engaged gear ratio.
• the estimation of the engine torque can be performed according to various more or less complex and precise models.
• the motor control can use a model based on the following formula:
• output indicates function of inlet pressure and speed
• the stability index Is is calculated as follows:
• This calculation can be averaged over several points in order to perform a low-pass filtering.
• Figure 2 shows an example of the course of the engine control strategy implemented by the method according to the invention.
• the engine control device involving a method according to the invention will calculate a crossover instruction of the distribution, according to a first index of stability calculated.
• the regulation thus achieved will increase the crossing of the valves as long as the engine remains stable (relative to the stability set), and this, according to a variant of the invention, to a certain predetermined limit.
• a backup strategy which may for example consist of adoption of a preset crossover of the predefined distribution and ensuring stability in a certain way, for example a zero crossing (request for rapid "uncrossing" of the engine), possibly accompanied by the adoption of advance control instructions at ignition and wealth
• a backup strategy which may for example consist of adoption of a preset crossover of the predefined distribution and ensuring stability in a certain way, for example a zero crossing (request for rapid "uncrossing" of the engine), possibly accompanied by the adoption of advance control instructions at ignition and wealth
• FIG. 3 shows the regulating function of the crossing of the valves implemented in the regulator 6.
• This regulator 6 integrates a summing function F1 able to take into consideration the output signal of three other functions:
• One or more of these functions are active according to the operating strategy determined by the supervisor 1.
• a set of crossover valves in the form of instructions for controlling the opening of the intake valves and closing of the exhaust valves, at the output of the summation function F1, can be determined:
• the summing function F1 takes into account only the output signal of the function for determining the basic setpoint F2
• the F1 summation function it takes into account the output signal of the basic setpoint determination function F2 the signal of the setpoint correction function F3.
• the summation function F1 takes into consideration the signals of the three functions for determining the basic setpoint F2, the setpoint correction F3, and the implementation of a backup strategy F4.
• the invention thus proposes a method for changing the crossing level of the distribution of an engine according to its stability, to adopt a setting allowing the maximum consumption gains obtained by crossing. In other words, it is possible to enslave the crossing at a desired level of stability so as to limit the maximum consumption of the engine.
• the invention can also be applied to the regulation of other parameters affecting the stability of the engine, such as the wealth or the ignition advance, aiming at obtaining a greater amount of power. available exhaust energy and / or reduction of polluting emissions.

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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)
• Combined Controls Of Internal Combustion Engines (AREA)

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Publications (2)

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Family Cites Families (7)

• 2010
  • 2010-02-09 FR FR1050874A patent/FR2956161B1/fr not_active Expired - Fee Related
• 2011
  • 2011-02-02 WO PCT/FR2011/050203 patent/WO2011098708A1/fr active Application Filing
  • 2011-02-02 CN CN201180008978.7A patent/CN102782296B/zh active Active
  • 2011-02-02 EP EP11708058.0A patent/EP2534355B1/de active Active

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