FR2969710A1 - Control device for internal combustion engine i.e. diesel engine, of motor vehicle, has correcting unit for correcting effect of dispersion measurement for modifying operating instructions in function of dispersion of ratio measurement - Google Patents

Abstract

The device (17) has a detection unit for determining operating instructions of an internal combustion engine, where the operating instructions comprise instruction fuel flow, setpoint quantity of air admitted and setpoint quantity of fuel to be injected. A judging unit (29) judges dispersion of measurement ratio based on a signal of a measuring unit (21) and a signal estimation unit (16). A correcting unit is provided for correcting effect of the dispersion measurement for modifying the operating instructions in function of dispersion of the ratio measurement. An independent claim is also included for a method for controlling an internal combustion engine of a motor vehicle.

Description

The invention relates to the control of internal combustion engines equipped with partial recirculation circuits for exhaust gas. The dispersions and drifts of the fuel and intake air flow meters distort the corresponding flow measurements used by the control means, in particular the regulation of the partial recirculation of the exhaust gases. The dispersions and drifts introduce a difference between the flow instructions and the actual flow, causing a difference between the actual operating point and the set operating point. The target operating point being determined so as to reduce the pollutant emissions, the divergences and drifts of measurement lead to a polluting operation. Diesel-type internal combustion engines generally include a partial exhaust gas recirculation (EGR) circuit located upstream or downstream of a compressor. The torque delivered by a diesel-type internal combustion engine is controlled by the amount of air inspired by the cylinders. In this operation, called the EGR zone, the partial recirculation of the exhaust gases is used to maintain the combustion stoichiometry. Beyond a certain couple, increasing the amount of inspired air can generate fumes. It is then necessary to limit the amount of fuel injected. This operation is called the smoke control zone. Regardless of the operating zone, the drifts and measurement dispersions must be corrected to ensure consistent operation with requests and instructions.

An object of the invention is to correct the dispersions and drifts of the fuel and air flow meters admitted during the operation of the internal combustion engine in the EGR zone. Another object of the invention is to correct the dispersions and drifts of the fuel and air flow meters admitted during operation of the internal combustion engine in the smoke control zone. According to one embodiment, there is provided a control device of an internal combustion engine fitted to a motor vehicle, the internal combustion engine being provided with a partial recirculation system of the exhaust gas and a turbocharger. The control device comprises means for determining the operating instructions of the internal combustion engine, the operating instructions comprising a fuel flow setpoint, an admitted air flow setpoint and a limit fuel quantity setpoint to be injected. The control device also comprises a means for measuring the richness, a means for estimating the richness, a means for estimating the dispersion of the richness measurement as a function of the signal of the means for measuring the richness and the signal. means for estimating the richness, and a means for correcting the effects of the measurement dispersion able to modify at least one of the operating instructions as a function of the dispersion of the richness measure. The control device has the advantage of correcting the drifts and dispersions of at least one of the operating instructions, in the EGR zone and in the smoke control zone. The control device also has the advantage of taking into account the partial recirculation circuit of the exhaust gas in the estimation of drifts and dispersions.

The means for correcting the effects of the measurement dispersion may comprise correction means capable of correcting the setpoint of the intake air flow rate as a function of the estimated value of the dispersion of the richness measurement, of the flow rate setpoint. air intake and fuel flow instruction.

The means for correcting the effects of the measurement dispersion may comprise a correction means adapted to correct the fuel flow setpoint as a function of the estimated value of the dispersion of the richness measurement, of the setpoint of the intake air flow rate. and the fuel flow instruction. The means for correcting the effects of the measurement dispersion may comprise a means of limiting the quantity of fuel to be injected able to emit a corrected value of the maximum quantity of fuel injected as a function of the corrected value of the dispersion of the measurement of the fuel. richness, the measurement of air flow and the maximum wealth estimated by the wealth estimation means receiving the maximum amount of fuel to be injected. The means of estimating the richness may be able to determine the richness of the mixture in the intake manifold as a function of the fuel flow rate, the air flow at the inlet of the engine, the flow rate of the intake air and the flow rate of the engine. compressor air. The means for estimating the dispersion of the richness measure may include a mapping of the dispersion of the richness measure.

The means for correcting the effects of the measurement dispersion may comprise a means for comparing the mapped value of the dispersion of the measurement of richness with the estimated value of the dispersion of the measure of richness, able to consider the value mapped and separate the estimated value if the mapped value and the estimated value match. The means for correcting the effects of the measurement dispersion may comprise means for storing the estimated value of the dispersion of the richness measure in the mapping of the dispersion of the measure of richness if the value of the measurement dispersion is mapped. of wealth is different from the estimated value of the dispersion of the wealth measure. The means for correcting the effects of the measurement dispersion may comprise means for detecting transient operation and means for correcting the mapped value of the dispersion of the measurement of richness as a function of the measured value of the richness, the estimated value of the wealth and a transient operating signal. The means for correcting the mapped value of the dispersion of the richness measure may comprise a means for comparing the mapped value of the dispersion of the measure of wealth with the estimated value of the dispersion of the measure of wealth, able to consider the mapped value and discard the estimated value if the mapped value and the estimated value match. According to another aspect, there is provided a method of controlling an internal combustion engine fitted to a motor vehicle, the internal combustion engine being provided with a partial recirculation system for the exhaust gas and a turbocharger, the method control system comprising a determination of the operating instructions of the internal combustion engine, the operating instructions comprising a fuel flow set point, an admitted air flow set point and a limit fuel quantity setpoint to be injected, characterized in that it comprises the following stages: - measurement of wealth, - estimation of wealth, - estimation of the dispersion of the measure of wealth according to the measure of wealth and the estimate of wealth, and - correction of effects of the measurement dispersion modifying at least one of the operating instructions as a function of the dispersion of the measurement of richness. The correction of the effects of the measurement dispersion can comprise a correction of the admission air flow rate setpoint as a function of the estimated value of the dispersion of the richness measurement, the admission air flow setpoint and the setpoint fuel flow.

The correction of the effects of the measurement dispersion can comprise a correction of the fuel flow setpoint as a function of the estimated value of the dispersion of the richness measurement, of the admission air flow setpoint and of the flow setpoint fuel. The correction of the effects of the measurement dispersion may include a limitation of the amount of fuel to be injected based on the corrected value of the dispersion of the richness measurement, the measurement of airflow and the maximum richness.

Other objects, features and advantages will appear on reading the following description given solely as a non-limitative example and with reference to the appended drawings in which: FIG. 1 illustrates a means for estimating the richness, FIG. 2 illustrates the main elements of a system for correcting the air flow setpoint in EGR regulation; FIG. 3 illustrates the main elements of a system for correcting the fuel quantity setpoint in EGR regulation, - Figure 4 illustrates the main elements of a fuel limitation system limitation in smoke limitation. In FIG. 1, we can see a first multiplier 1 receiving as input the air flow through the connection 2 and the estimate of the exhaust richness by the connection 3. A means of estimating the composition 5 is connected at the input to the first multiplier 1 by the connection 4. The estimation means 5 receives the air flow sucked into the engine by the connection 6 and the compressor flow through the connection 7. The estimation means 5 emits output a value of wealth in the intake manifold. A second multiplier 10 is connected to the output of the estimation means via the connection 8 and receives as input the flow of air inspired in the engine by the bypass 9 of the connection 6. A calculation means 12 of the wealth is connected at the input to the second multiplier 10 by the connection 11 and the bypass 9 by the connection 13. The calculation means 12 also receives the input fuel flow through the connection 14. The calculation means 12 outputs an estimate of the wealth in the exhaust manifold. The estimation means 5, the calculating means 12, the first multiplier 1 and the second multiplier 10 are included in a wealth estimation means 16. The richness in the exhaust manifold Ri is determined in the following manner (PCO + 1) 'QR f, calc i, is = D (Eq. 1) + word D Qf, calc D air, mes c with PCO = stoichiometric ratio (14.5 for diesel) Qf, shim = Estimated fuel flow Dmot = Engine intake airflow Dc = Fuel flow Air, mes = Measured airflow 15 EGR correction systems will be presented with reference to FIGS. 2 and 3. The correction systems in the smoke control zone will be presented with reference to FIG. 4. FIG. 2 shows a control device 17 of an internal combustion engine 18 of FIG. diesel type. The control device 17 receives a value of the air flow sucked into the engine via the connection 6, a value of the flow rate of the compressor via the connection 7, a value of the torque setpoint via the connection 19, a value of the speed the rotation of the motor through the connection 20, a measurement of the exhaust richness measured by the richness probe 21 by the connection 22. It can be seen a map 23 of the quantity of fuel to be injected receiving the rotation speed input the motor 20 via the connection 20 and the torque setpoint via the connection 19. The map 23 outputs the fuel setpoint to be injected via the connection 24 to the injectors 25.10. input the engine rotational speed by a bypass 27 of the connection 20 and the fuel setpoint to be injected by a bypass 28 of the connection 24. The air flow map 26 outputs a setpoint of air flow through the connection 29. A wealth estimator 16 receives as input the fuel charge to be injected through the connection 14, the air flow measurement via the connection 2, the air flow sucked into the engine by the connection 6 and the flow of the compressor through the connection 7. The wealth estimator 16 is connected at the output by the connection 15 to a means 29 for estimating the dispersion of the richness measure. The means 29 for estimating the dispersion of the measurement of richness also receives the measure of richness at the escapement via the connection 22. The means 29 for estimating the dispersion of the richness measure determines a value K, called residue, characterizing the drifts and dispersions of operating variables, such as the quantity of fuel to be injected and the flow of air admitted. The residue K is determined by the following equation: K - (PCO + 1) (R ,, mes -R is R ,, is' PCO + 1) - R ,, mes (Eq-2) with Rhes = the measure of richness in the exhaust.

The means 29 for estimating the dispersion of the richness measurement is connected at the output by the connection 30 to a first subtractor 31. The first subtractor 31 is connected to an input of a learning means 33 via the connection 32 and an input at the output of the learning means 33 by the connection 35. The learning means 33 is connected at input to a means for detecting a stabilized operation 45 by the connection 46. The learning means 33 is connected by the connection 34 to a calculating means 36. The calculating means 36 is connected at the output to a third multiplier 38 by the connection 37. The third multiplier 38 also receives as input the air flow instruction by the connection 29 and outputs a corrected setpoint of air flow through the connection 39 to a second subtractor 40. The learning means 33 compares the calculated value of the residue with respect to the value previously issued. As soon as there is a significant difference between a new estimated value of the residue and the value emitted at the output of the learning means 33, the value emitted at the output of the learning means 33 takes the new estimated value of the residue. Otherwise the value emitted at the output of the learning means 33 remains unchanged.

Simultaneously, if a new estimated value of the residue is emitted at the output of the learning means 33, and if the operating conditions of the engine are stable, the new estimated value of the residue is stored. The learning means 33 receiving the difference between the value outputted and the new estimated value, the value of the residue is estimated by adding the difference to the value emitted at the output. Although the connection is not shown in FIGS. 2 to 4, the learning means receives the Rhimes richness measure making it possible to map the residual K as a function of the Rhimes richness measure. Only the values of K determined for steady-state operation are stored. Thus, if the value of the residue K for the richness measure R ,, m S is available, the value of the residue K is issued without waiting for the result of the calculation by the estimation means 29 of the dispersion of the richness measure. The system is thus reactive, without waiting for the convergence of the estimation calculation of the residue. The calculation means 36 performs the calculation (1 + K). The corrected setpoint of air flow is determined at the level of the second multiplier 38 by the following equation: Dair, sp, corr = (1 + K) 'Dair, sp (Eq-3) with Dair, sp = the setpoint of air flow Dair, sp, eorr = the corrected setpoint of air flow K = the residue The second subtractor 40 receives as input a measurement of the flowmeter 42 of air admitted by the connection 41. A control means 44 of the partial recirculation of the exhaust gas receives as input the difference between the air intake setpoint and the intake air measurement from the second subtractor 40 by the connection 43. In FIG. 3, a system for correcting the air intake can be seen. fuel flow setpoint in EGR regulation. A map 23 of the quantity of fuel to be injected can be seen receiving, at the input, the speed of rotation of the engine via the connection 20 and the torque setpoint via the connection 19. The map 23 outputs the connection of the fuel setpoint to the inject, to the injectors 25 by the connection 24.

A wealth estimator 16 receives as input the fuel quantity to be injected via the connection 14, the measurement of the air flow through the connection 2, the air flow sucked into the engine by the connection 6 and the flow rate of the compressor by the connection 7. The wealth estimator 16 is connected at the output by the connection 15 to an estimation means 29 of the dispersion of the richness measure. The means 29 for estimating the dispersion of the richness measure also receives the measure of richness at the escapement via the connection 22. The residue is determined by the equation Eq. 2 previous. The means 29 for estimating the dispersion of the richness measurement is connected at the output by the connection 30 to a first subtractor 31. The first subtractor 31 is connected to an input of a learning means 33 via the connection 32 and by another input to the output of the learning means 33 through the connection 35. The learning means 33 is input connected to a means for detecting a stabilized operation 45 by the connection 46. The learning means 33 is connected via the connection 34 to a calculating means 36. The calculating means 36 is connected at the output to a first multiplier 38. The first multiplier 38 also receives as input the fuel quantity instruction via the connection 28 and outputs a corrected set of fuel quantity through the connection 28b to a map 26 of the intake air flow. The learning means 33 has a similar operation to the described operation of the learning means 33 with regard to FIG. 2. The calculation means 36 performs the calculation (1 + K). The corrected setpoint of fuel quantity Qf, sp, aorr is determined at the level of the second multiplier 38 according to the following equation (: Qf, sp, corr = (1 + K)) Qf, sp (Eq-4 ) with Qf, sp = the fuel quantity setpoint The air intake flow map 26 receives as input the rotation speed of the engine by a bypass 27 of the connection 20 and the corrected setpoint of fuel to be injected by the connection 28b.

The mapping 26 of the intake air flow emits an air flow setpoint via the connection 39. A second subtractor 40 receives as input a measurement of the air flowmeter 42 admitted by the connection 41 and the flow rate setpoint. air through the connection 39.

A regulating means 44 of the partial recirculation of the exhaust gas receives as input the difference between the set air intake and the intake air measurement from the second subtractor 40 through the connection 43. FIG. 4 illustrates the main elements a fuel limitation system for limiting smoke. The fuel charge to be injected has previously been limited. The value considered here is therefore the maximum value of fuel to be injected. A richness estimator 16 receives as input the maximum value of fuel to be injected by the bypass 47 of the connection 48 and the measurement of the air flow through the connection 2. The wealth estimator 16 is connected at the output by the connection 15 to a means 29 for estimating the dispersion of the richness measure. The means 29 for estimating the dispersion of the richness measure also receives the measure of richness at the escapement via the connection 22. The residue is determined by the equation Eq. 2 previous. The means 29 for estimating the dispersion of the richness measure is connected at the output by the connection 30 to a first subtractor 31. The first subtractor 31 is connected by an input to an input of a learning means 33 by the connection 32 and another input to the output of the learning means 33 through the connection 35. The learning means 33 is input connected to a means for detecting a stabilized operation 45 by the connection 46. The means learning 33 is connected at the output to a third subtracter 49 by a connection 34. The third subtracter 49 is input connected to the output of the estimation means 29 of the dispersion of the richness measurement by the connection 50. The third subtractor 49 is outputted to a scalar learning means 52 through the connection 51. The scalar learning means 52 receives an input signal via the connection 53 and outputs a signal Kpi through the connection 54. The learning means 33 has a similar operation to the described operation of the learning means 33 with regard to FIG. 2. Unlike the learning means 33, the scalar learning means 52 only operates in a transient state. Under transient conditions, the operating points are different from the steady-state operating points. The values from the learning means 33 do not correspond. These values, however, represent a good approximation of the correction to be made. To refine the correction, the scalar learning means 52 determines a corrective term added to the residue K and making it possible to match the corrected value of the residue Kc with the transient operating point. In other words, the sum Kc of the value of the residue emitted at the output of the learning means 33 and the term Kpi transmitted at the output of the scalar training means 52 must tend towards the value of K determined by the equation Eq. . 2 applied to the transient operating point. The combination of the learning means 33 and the scalar learning means 52 makes it possible to shorten the calculation time necessary for the determination of the correction to a value compatible with the shortness of the transient operating points.

An adder 55 is input connected to the connection 54 and to the output of the learning means 33 by the bypass 56 of the connection 35. The adder 55 transmits via the connection 57 a corrected value of the residual to a means of calculation 58 of the correction of the maximum fuel quantity.

The correction of the maximum quantity of fuel Mfuel, max, eor is determined by the calculating means 58 by applying the following equation: M = Ke R D .. air, fuel, max, cor 1 + K '' max

PCO e with Ri, max = maximum Wealth Ke = residual value of the residual The maximum richness Ri, max is determined by the following equation: D air, r with Qfmax, r = Maximum actual fuel flow rate Dair, r = Flow rate actual air The actual maximum fuel flow is a function of the engine rotation speed and the estimated engine air flow and is experimentally identified. The actual air flow rate corresponds to a measurement of the fresh air flow, measured by an air flow meter. A fourth subtractor 60 receives as input the maximum quantity of fuel Mfuel, max by the connection 48 and the correction of the maximum fuel quantity Mfuel, max, eor by the connection 59. The fourth subtractor 60 outputs a corrected value Mfuel, max, e 30 of the maximum quantity of fuel via the connection 61 to the injectors 25. The corrected value Mfuel, max, e of the maximum quantity of fuel is determined by the following equation: (Eq.5) R, = PCO Qfinax, r (Eq. 6) 20 M rual, max, e = M rual, max - M rual, max, cor (E q 7) A mapping 26 of the intake air flow receives as input the speed of rotation of the motor 27 by a connection and the maximum amount of fuel to be injected by the bypass 28 of the connection 48. The mapping 26 of the intake air flow emits an air flow setpoint via the connection 39. A second subtractor 40 receives as input a measurement of the air flow meter 42 admitted by the connection 41 and the air flow instruction via the connection 39.

A regulating means 44 of the partial recirculation of the exhaust gases receives as input the difference between the set air intake and the intake air measurement coming from the second subtractor 40 via the connection 43.

Claims (14)

REVENDICATIONS1. A control device for an internal combustion engine fitted to a motor vehicle, the internal combustion engine being provided with a partial recirculation system for the exhaust gas and a turbocharger, the control device comprising means for determining the operating instructions of the internal combustion engine, the operating instructions comprising a fuel flow set point, an admitted air flow set point and a maximum fuel quantity to be injected, characterized in that it comprises means for measure (21) of wealth, means for estimating (16) wealth, means for estimating (29) the dispersion of richness measure as a function of the signal of wealth measuring means (21) and the signal of the wealth estimating means (16), and a means for correcting the effects of the measurement dispersion adapted to modify at least one of the operating instructions as a function of the dispersion of the measure of wealth. 2. Device according to claim 1, wherein the means for correcting the effects of the measurement dispersion comprises correction means adapted to correct the air flow rate setpoint as a function of the estimated value of the dispersion of the measurement of richness, the air flow setpoint and the fuel flow setpoint. 3. Device according to claim 1, wherein the means for correcting the effects of the measurement dispersion comprises a correction means adapted to correct the fuel flow setpoint as a function of the estimated value of the dispersion of the measurement of richness, the set flow rate and the fuel flow setpoint. 4. Device according to any one of the preceding claims, wherein the means for correcting the effects of the measurement dispersion comprises means for limiting the maximum amount of fuel to be injected able to emit a corrected value of the maximum quantity of fuel. injected according to the corrected value of the dispersion of the richness measurement, the air flow measurement and the maximum wealth estimated by the wealth estimation means receiving the maximum quantity of fuel to be injected. 5. Device according to any one of the preceding claims, wherein the means (16) for estimating the richness is able to determine the mixture richness in the intake manifold as a function of the fuel flow rate, the flow rate. air at the engine inlet, the intake air flow and the compressor air flow. The apparatus of any one of the preceding claims, wherein the means for estimating (29) the dispersion of the richness measure comprises mapping the dispersion of the richness measure. The apparatus of claim 6, wherein the means for correcting the effects of the measurement dispersion comprises means for comparing the mapped value of the dispersion of the measure of richness with the estimated value of the dispersion of the measure of wealth. , able to consider the value mapped and to discard the estimated value if the mapped value and the estimated value correspond. 8. Device according to claim 7, in the means for correcting the effects of the measurement dispersion comprises means for storing the estimated value of the dispersion of the measurement of richness in the mapping of the dispersion of the measure of richness if the Mapped value of the dispersion of the measure of wealth is different from the estimated value of the dispersion of the measure of wealth. 9. Device according to any one of claims 6 to 8, wherein the means for correcting the effects of the measurement dispersion comprises means for detecting transient operation and means for correcting the mapped value of the dispersion of the dispersion. measurement of richness as a function of the measured value of the wealth, the estimated value of the wealth and a transient operating signal. The device of claim 9, wherein the means for correcting the mapped value of the dispersion of the richness measure comprises means for comparing the mapped value of the dispersion of the richness measure with the estimated value of the dispersion. of the richness measure, able to consider the value mapped and to discard the estimated value if the mapped value and the estimated value correspond. 11. A method of controlling an internal combustion engine fitted to a motor vehicle, the internal combustion engine being provided with a partial recirculation system of the exhaust gas and a turbocharger. the control method comprising a determination of the operating instructions of the internal combustion engine, the operating instructions comprising a fuel flow set point, an admitted air flow set point and a maximum fuel quantity to inject regulation characterized by the fact that it comprises the following stages: - measurement of wealth, - estimation of wealth, - estimation of the dispersion of the measure of wealth according to the measure of wealth and the estimation of wealth, and - correction of the effects of the measurement dispersion modifying at least one of the operating instructions as a function of the dispersion of the measurement of richness. 12. The method of claim 11, wherein the correction of the effects of the measurement dispersion comprises a correction of the admitted air flow rate setpoint as a function of the estimated value of the dispersion of the richness measurement, of the flow setpoint. air intake and the fuel flow instruction. 13. The method of claim 11, wherein the correction of the effects of the measurement dispersion comprises a correction of the fuel flow setpoint as a function of the estimated value of the dispersion of the richness measurement, the flow rate setpoint air intake and the fuel flow instruction. The method according to any one of claims 11 to 13, wherein the correction of the effects of the measurement dispersion comprises a limitation of the maximum amount of fuel to be injected as a function of the corrected value of the dispersion of the richness measure. , air flow measurement and maximum wealth.