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
  • F02D41/0002—Controlling intake air
  • F02D41/0007—Controlling intake air for control of turbo-charged or super-charged engines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
  • F02B37/004—Engines characterised by provision of pumps driven at least for part of the time by exhaust with exhaust drives arranged in series
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
  • F02B37/013—Engines characterised by provision of pumps driven at least for part of the time by exhaust with exhaust-driven pumps arranged in series
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
  • F02B37/12—Control of the pumps
  • F02B37/18—Control of the pumps by bypassing exhaust from the inlet to the outlet of turbine or to the atmosphere
• • 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
  • F02D41/1448—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 an exhaust gas pressure
• • 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
  • F02D2200/04—Engine intake system parameters
  • F02D2200/0406—Intake manifold pressure
• • 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

• the invention relates to the control of internal combustion engines of motor vehicles.
• the invention relates to the control of the two-stage air supercharging of such engines.
• a particularly interesting application of the invention concerns the control of the supercharging of a supercharged diesel engine with a turbocharger, and more particularly with a two-stage turbocharger architecture.
• the control of the engine is the technique of adjusting the performance of an internal combustion engine by controlling all of its sensors and actuators.
• ECU Electronic Control Unit
• Supercharged engines comprise a turbocharger comprising a turbine driven in rotation by the exhaust gas and a compressor driven by the turbine and serving to increase the amount of air admitted into the cylinders.
• the turbine is placed at the outlet of the exhaust manifold while the compressor is mounted on the same axis as the turbine and is disposed upstream of the intake manifold.
• the turbochargers are connected in series, so that the low pressure compressor supplies the high pressure compressor with air and the high pressure turbine supplies the low pressure turbine with gas.
• the power provided by the exhaust gases to the high and low pressure turbines can be adjusted by installing relief valves or vanes which affect the flow rate of gas passing through the turbine or the passage section provided for these gases.
• This type of turbocharger is called a fixed geometry turbocharger.
• the boost pressure level is increasing so that turbochargers are more and more stressed. It is therefore important to control the turbochargers as finely as possible in order to prevent them from deteriorating and to improve the behavior of the turbochargers. during accelerations, and in particular to increase the dynamics of the engine, that is to say, its ability to climb quickly in regime.
• Regulation of the pressure in the intake manifold of the engine around the pressure reference value is conventionally carried out by means of regulators P1D (Proportional, Integral, Differential) after revolution of the difference between the pressure setpoint and the actual pressure measured.
• regulators P1D Proportional, Integral, Differential
• the object of the invention is therefore to overcome these disadvantages and to provide a method and a device for controlling the supercharging of a supercharged internal combustion engine to achieve this triple objective, namely control of the supercharging pressure by transient regime, control of the boost pressure in steady state and limitation of the pressure upstream of the turbine.
• control method advantageously uses a compression ratio variable compressor to drive a turbocharger in the case where it is unique.
• the method replaces a dual-loop control by a control at a given moment of one or other of the turbochargers, combined with a manager that selects the turbocharger piloted.
• the object of the invention is therefore, according to a first aspect, a method for controlling the supercharging of an internal combustion engine of a motor vehicle equipped with a stepped two-turbocharger comprising two turbines driven in rotation by the gases. engine exhaust, two superchargers driven by each of the turbines, and two high pressure and low pressure valve actuators for adjusting the power of the exhaust gas.
• This method furthermore comprises the regulation of the compression ratio of the compressor around a setpoint value of the supercharging pressure ratio, as well as a regulation of the expansion ratio to limit the pressure upstream of the turbine, the regulation being set implemented as soon as the pressure upstream of the turbine exceeds a threshold value.
• an aetivation and deactivation signal is produced for regulating the expansion ratio of the turbine as a function of the value of the pressure in the intake manifold and the pressure upstream of the turbine. the turbine of the turbocharger and according to the first and second threshold values.
• the regulation of the expansion ratio of the turbine is deactivated when the value of the pressure in the intake manifold is greater than or equal to the first threshold value.
• the regulation of the compression ratio of the compressor is deactivated when the value of the pressure in the exhaust manifold is lower than the second threshold value.
• the pressure limitation upstream of the turbine is effected by means of a regulation loop receiving as input the setpoint value and an estimate of the compression ratio of the compressor and delivering an output control signal for high pressure and low pressure valve actuators.
• Switching means arranged at the input of the regulation loop can be controlled according to the value of the activation and deactivation signal, so as to present at the input of the regulation loop, on the one hand, or the estimation the expansion ratio of the turbine, ie the estimation of the compression ratio of the compressor, and on the other hand, one or the other of the set values.
• the compression compressor compression setpoint can be developed from a mapping and the expansion ratio setpoint can be derived from the ratio of the pressure in the exhaust manifold to one or the other. other pressure values among the pressure measurement downstream of the low pressure turbine and the estimation of the pressure downstream of the high pressure turbine.
• the value of estimating the pressure downstream of the high-pressure turbine is derived from a dynamic model of the turbocharger at low pressure.
• the invention relates to a device for controlling the air supercharging of an internal combustion engine of a motor vehicle equipped with a stepped supercharger twin turbocharger provided with two turbines driven by the gases of engine exhaust, two superchargers driven by each turbine.
• the device comprises a control unit comprising the regulation of the compression ratio of the compressor around a set value of the pressure ratio of supercharging and regulating the expansion rate so as to limit the value of the pressure upstream of the turbine, said regulation being implemented as soon as the pressure upstream of the turbine exceeds the threshold value.
• a map is used in which prepositioning values of the high pressure and low pressure valve actuators are stored, making it possible to adjust the power of the exhaust gases as a function of engine operating parameters and means for pre-shaping. said actuators from a value extracted from the map.
• FIG. 1 schematically illustrates the structure of an internal combustion engine, of diesel type, of an automobile engine provided with a supercharging control device according to the invention:
• FIG. 2 represents a control stage of a circuit
• - Figure 3 illustrates a dynamic estimator of a low pressure turbocharger based on a physical model.
• FIG. 1 diagrammatically shows the general structure of an internal combustion engine 1 of a motor vehicle, of the Diesel type, as well as its fresh air intake 2 and exhaust manifolds. 3.
• the fresh air intake circuit 4 in the engine 1 essentially comprises an air filter 5 supplying, via a first stage of turbocharger 6 low pressure and a second 7 high pressure turbocharger stage, the intake manifold 2 of the engine 1.
• the exhaust manifold 3 With regard to the exhaust manifold 3, it recovers the exhaust gases from the combustion and evacuates these the latter to the outside, via turbochargers 6 and 7 and a particulate filter 8 intended to reduce the amount of particles, especially soot, released into the environment.
• the turbocharger 6 essentially comprises a turbine 10 driven by the exhaust gas and a compressor 11 mounted on the same axis as the turbine 10 and providing a compression of the air distributed by the air filter 5, in order to increase the amount of air admitted into the cylinders of the engine 1.
• the turbocharger 7 essentially comprises a turbine 1 2 driven by the exhaust gas and a compressor 1 3 mounted on the same axis as the turbine 12 and providing a compression of the air distributed by the compressor 1 1, for the purpose of increase the amount of air admitted into the cylinders of the engine 1.
• the engine 1 is also associated with an exhaust gas recirculation circuit 14 for injecting a part of these gases into the intake manifold 2 so as, in particular, to limit the amount of exhaust gas. nitrogen oxide produced while avoiding the formation of smoke in the exhaust.
• This circuit 14 essentially comprises a solenoid valve 15 which makes it possible to control the flow of recirculated exhaust gas.
• the engine 1 is associated with a circuit 16 for exhausting gases.
• This circuit 1 6 essentially comprises high-pressure discharge valves 17 as in the English terminology under the term 'by-pass' valve and low pressure 1 8, generally designated by the English terminology under the term 'wastegate' valve, so as to modulating the power provided by the exhaust gases to the high and low pressure turbines 10 and 12.
• One of the principles of the invention is to drive only one turbocharger 6 or 7 at a time by acting on the high pressure valve actuator 17 or low pressure 18 corresponding.
• a controlled electronic unit ECU designated by the reference numeral 20, retrieves signals P and P avt al, t for measuring the pressure respectively prevailing in the intake manifold 2 and upstream of the high pressure turbine 12 , delivered by appropriate measuring sensors provided for this purpose (not shown).
• It acts on a device for adjusting the power of the exhaust gases, for example the discharge valves so as to regulate the value of the pressure prevailing in the intake manifold 2 and the value of the pressure P avl, l in upstream of the turbine 12 of the turbocharger 7 around respective setpoints CONSp coll and CONSp avt .
• the unit UCE 20 also provides the operational control of the engine 1, in a manner known per se. It acts in particular on the solenoid valve 1 5 to adjust the amount of recirculated gas and adjusts the operating point of the engine 1.
• the present description relates to the limitation of the pressure P avt t upstream of the turbine 12 of the high pressure turbocharger 7. Also, the following description of the ECU unit 20 will relate to the essential means for implementing this limitation.
• the electronic control unit ECU 20 mainly comprises a regulating means for limiting the pressure P avt, t upstream of the turbine 12 of the turbocharger 1.
• the central unit 20 incorporates a regulation stage 21 of the expansion ratio PR t receiving as input the estimated expansion ratio PR t, esti and the estimated compression ratio PR c, esti , a first stage 22 of elaboration a first pressure threshold value CONSp coll corresponding to a maximum permissible pressure value for the intake manifold 2 and a second stage 23 for producing a second threshold value CONSp avl of pressure corresponding to a maximum value authorized pressure for the exhaust manifold 3, corresponding to the authorized pressure upstream of the turbine 12 of the turbocharger 7 high pressure.
• the central imitate 20 also incorporates a third stage 24 and 25 of elaboration of the estimation of the expansion ratio PR t, esti of the turbine, respectively at high pressure and at low pressure, as well as a fourth stage 26 and 27 for developing the setpoint value PR t, cons of the expansion ratio of the turbine, respectively at high pressure and at low pressure.
• the limitation of the pressure P avt, t prevailing upstream of the turbine 12 is active only when the P avt pressure, t upstream of the turbine 12 is greater IA first threshold value Consp avt .
• the regulation of the expansion ratio PR t is implemented by the third and fourth stages 24, 25 and 26, 27 of the ECU control unit 20.
• this stage consists of a two-input memory zone into which data, obtained by learning, are loaded. beforehand, constituted by a set of pressure threshold value CONSp coll each corresponding to an operating speed of the engine and a fuel consumption level,
• stage 23 for developing the second threshold value CONSp avt it is also constituted by a memory zone in which is loaded a threshold value CONSp avt corresponding to a maximum pressure value from which malfunctions are likely to appear within turbochargers 6 and 7.
• This threshold value CONSp avt is preferably completed by a setpoint value CONS 21 corresponding to a setpoint value in transient mode and by a setpoint value CONS 2p corresponding to a setpoint value in steady state.
• the regulation stage of the expansion ratio essentially comprises a circuit. Essentially incorporating a regulator 26.
• the circuit 25 receives, as input, an error signal E delivered by a comparator 30 ensuring either the comparison between the value of reference of the expansion ratio PR t, cons and the estimation of the expansion ratio PR t, esti , ie the comparison between the setpoint value of the compression ratio PR c, cons and the estimation of the compression ratio PR c, esti .
• the circuit 25 also incorporates a stage 31 for generating a GPAVT signal for activating and deactivating the regulation of the expansion ratio PR t .
• CPAVT this signal is generated in a logic circuit 32 based on the pressure P coll of value in the intake manifold 2, the pressure P avt, t upstream of the turbine 12 of the turbocharger 7, and based on setpoint values CONS coll and CONS pavt .
• the floor 3 1 d preparation of CPAVT signal comprises first means 33 for ensuring a comparison between the comparison al P measured pressure value in the intake manifold 2 and the al CONS corresponding reference value, and comparing means 34 for comparison between the pressure value P avt t measured in the exhaust manifold 3 and the threshold value CONS corresponding flag , the result of these comparisons being provided to the logic circuit 32 suitable for the elaboration the activation and deactivation signal CPAVT.
• the signal CPAVT allows to actuate switches 35 and 36 so as to position them on the reference of the relaxation ratio PR t, cons of the turbine 12 and on the estimation of the expansion ratio PR t, esti .
• the comparator 30 makes a comparison between the estimate of the expansion ratio PR t, esti and the reference of the expansion ratio PR t, cons .
• the signal CPAVT makes it possible to actuate switches 35 and 36 so as to position them on the threshold value of the compression ratio PR c. of the compressor 13 and on the estimation of the compression ratio PR c, esti .
• the comparator 30 makes a comparison between the estimation of the compression ratio PR c, esti and the threshold value of the compression ratio PR c, cons .
• the error signal E delivered by the comparator 30 is transmitted to a regulator 37, so as to regulate either the expansion ratio PR t of the turbine 1 2, or the compression ratio PR c of the compressor 13.
• a prepositioning value of the low pressure (“bypass") and high pressure (wastegate) valves 18 is added to the output value of the regulator 37.
• This prepositioning value is extracted from a map C as a function of the engine speed N or the fuel flow W.
• This pre-positioning map C of the turbine 12 is incorporated in the ECU 20 and makes it possible to obtain a first estimated value of the adjustments of the turbocharger 7 as a function of the speed N and of the speed W and thus facilitate the adjustment. Moreover, by correcting the value extracted from the map C as a function, in particular, of the atmospheric pressure and of the temperature, it is possible to refine the prepositioning value of the turbine 12 as a function, for example, of the altitude, or the ambient temperature. It will be noted that this prepositioning value of the turbine 12 makes it possible to position the turbocharger 7 in a valid initial state during stable speeds and which thus makes it possible to approach transient conditions with a good initial setting.
• the outputs of the regulator 37 and the map C are summed by means of a summon 38 to determine the position of the valves WG low pressure discharges 1 8 and high pressure 17.
• the dynamic behavior of the estimator of the low-pressure turbocharger 6 is based on a physical model and to determine the estimation of the pressure P avt, t upstream of the turbine 1 0 low pressure, and the pressure P downstream, c downstream of the compressor 1 1 low pressure.
• This dynamic estimate of the low-pressure turbocharger 6 makes it possible to eliminate the risks of overspeed on the high-pressure turbocharger under transient conditions without the addition of a specific sensor.
• the dynamic estimator has as input the flow rate W avt, c of the compressor air 1 1 measured by a flow meter (not shown), the pressure values P avt, c and temperature T avt, c upstream of the compressor 1 l , the flow rate W avt t of the low pressure turbine 10 and the value of the temperature T avt t upstream of the low pressure turbine 10.
• the air flow values W avt, c and W avt, t and the pressure values P avt, c and P avt t are obtained by sensors (not shown).
• the flow rate W avt.c and the temperature T avt c upstream of the compressor 11 are measured.
• Cp is the heat capacity at constant pressure of the fluid flowing in the turbocharger 6 and the ratio of the heat capacity to constant pressure on the heat capacity at constant volume of the same fluid.
• the compression ratio PR c, esti and the efficiency ⁇ c are obtained from static C maps provided by the turbocharger manufacturer. These quantities are calculated according to variables determined by the following formulas:
• the pressure P avt, c upstream of the compressor 1 1 low pressure is measured.
• the turbocharger N t regime is provided by the dynamic estimator, functions f 1 and f 2 for them data from the manufacturer of the turbocharger and contained in the block 4 l.
• the air flow W avt, c may for example be measured by means of a hot wire sensor (not shown) placed at the outlet of the air filter 5.
• the pressure P avt, c may in turn be measured by a sensor piezoelectric (not shown).
• the power P t supplied by the turbine 10 to the motor shaft is calculated according to equation (4) in block 42:
• the functions fj, 3 ⁇ 4 are provided by the manufacturer and contained in block 43.
• the flow rate W avt t of the turbine 10 is estimated from the air flow rate measured at the air inlet of the engine 1, using a first-order low-pass filter (not shown). ). This simplification is justified by the fact that the low pressure estimator is used only when the valve (wastegate) is closed.
• the efficiency ⁇ t of the turbine 10 is thus determined from known or estimated quantities.
• equation (4) requires to know the expansion ratio PR t, esti of the low pressure turbine, since this is not measured.
• the pressure measurement P d tB P is used downstream of the low pressure turbine 10 and the equation (6) is reversed, so as to obtain the following equation:
• J Pinettie of the turbocharger 6 low pressure ⁇
• N t is the speed of the low pressure turbine.
• the setpoint PR t, soll is made from the ratio between the measurement of the pressure P avt, t upstream of the turbine and the P dt pressure value is downstream of the 12 high-pressure turbine or downstream of the low pressure turbine.
• the reference value of the expansion ratio PR t, cons is calculated according to the following equation:

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Supercharger (AREA)

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Citations (7)

• 2009
  • 2009-12-02 FR FR0958579A patent/FR2953253B1/fr active Active
• 2010
  • 2010-10-28 CN CN201080062602.XA patent/CN102770646B/zh active Active
  • 2010-10-28 EP EP10788107A patent/EP2507494A1/de not_active Withdrawn
  • 2010-10-28 WO PCT/FR2010/052313 patent/WO2011067491A1/fr active Application Filing

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