JP2009210426A - Adaptation method and adaptation device for engine control parameter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adaptation method and an adaptation device for an engine control parameter, to positively avoid over-time deterioration of engine characteristics of an engine including a control device having response delay, and to sufficiently improve fuel economy performance. <P>SOLUTION: The adaptation method for an engine control parameter includes the steps of: acquiring engine characteristic data of the engine during steady-state operation; determining a response surface function with the engine control parameter as an explanatory variable and an engine characteristic value as an objective variable; and determining an adaptation value of the engine control parameter using the response surface function so that a predetermined engine characteristic value satisfies a predetermined constraint condition in the case where a response delay of a response delay parameter occurs during operation over time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine control parameter adaptation method and adaptation apparatus.

  In an automobile engine, complicated control is performed so that engine characteristics such as exhaust gas characteristics, fuel consumption characteristics, combustion stability, and power performance satisfy various requirements.

  In other words, electronic control for engine control is set in advance by setting appropriate values for each control parameter such as the optimal fuel injection amount and optimal ignition timing according to the engine operating state determined based on the engine speed and load. Stored in the unit (ECU). Then, the ECU controls the engine while referring to the set adaptation value. Different requirements for each engine characteristic are met by using adapted values corresponding respectively to different operating conditions.

The process of obtaining the optimum value of each control parameter is usually as follows.
(1) A two-dimensional operation region defined by the engine speed and load is divided into a grid. At each grid point, the engine is operated in a number of control states with different values of each control parameter, and various engine characteristics are measured.
(2) Based on the measurement result of the above (1), a model formula (response surface function) having a plurality of control parameters as explanatory variables and respective engine characteristic values as objective variables is obtained for each grid point.
(3) For each grid point, using the response surface function obtained in (2) above, characteristics such as exhaust gas characteristics and combustion stability (torque fluctuation) satisfy predetermined constraints, and fuel consumption Find the point that minimizes. This point is the optimum value of each control parameter.

JP 2007-40929 A Japanese Patent Laid-Open No. 2007-9808 JP-A 63-170563 JP 2004-68729 A

  According to said method, the optimal value of each control parameter can be calculated | required for every lattice point of the driving | operation area | region of an engine. When the engine speed and load are in a steady operating condition, control each control parameter to the optimal value corresponding to the grid point (or the interpolated value of the grid point when it is between the grid points). By doing so, it is possible to realize an optimum operating state that satisfies various constraints and minimizes fuel consumption.

  However, in an automobile engine, a transient operation state in which the rotation speed and the load change is frequently used. In the transient operation state, a response delay occurs in some control devices. That is, control parameters such as ignition timing can be changed instantaneously. On the other hand, for example, the valve timing in the variable valve timing mechanism is changed by the operation of a hydraulic actuator or the like, and cannot be changed instantaneously. For this reason, a response delay of the variable valve timing mechanism is likely to occur during acceleration or deceleration.

  When the valve timing changes, the proper ignition timing also changes. Therefore, when a response delay of the variable valve timing mechanism occurs, the combination with the ignition timing tends to be inappropriate. That is, the ignition timing becomes an excessive advance angle or an excessive delay angle, and the torque fluctuation is likely to deteriorate. Moreover, in the middle load range, there is a concern about transient knocking.

  In order to prevent engine characteristics from deteriorating due to the response delay of the variable valve timing mechanism during transient operation as described above, the amount of change is corrected to be uniformly smaller than the optimal valve timing during steady operation. The adjusted valve timing is set as the applicable value. As a result, there is a problem that the fuel efficiency improvement effect due to the variable valve timing cannot be sufficiently obtained.

  The present invention has been made to solve the above-described problems, and in an engine having a control device in which a response delay occurs, the engine characteristics at the time of transition are not deteriorated and the fuel consumption performance is sufficiently improved. It is an object of the present invention to provide an engine control parameter adaptation method and adaptation apparatus that can be used.

In order to achieve the above object, a first invention is a method for adapting a plurality of engine control parameters including a response delay parameter that is likely to cause a response delay.
A data acquisition step for measuring engine characteristic data when the engine is in steady operation;
A response surface function obtaining step for obtaining a response surface function having the engine control parameter as an explanatory variable and the engine characteristic value as an objective variable based on the engine characteristic data;
The engine control parameter is set so that a predetermined engine characteristic value satisfies a predetermined constraint when it is assumed that a response delay occurs in the response delay parameter in accordance with a change in the engine load and / or the rotational speed. A fitness value obtaining step for obtaining a fitness value using the response surface function;
It is characterized by providing.

The second invention is the first invention, wherein
The adaptive value acquisition step includes
Using the response surface function, obtaining a steady optimum value that is an optimum value of the engine control parameter during steady operation;
Obtaining a fluctuation region of the response delay parameter when the engine load and / or the number of revolutions is changed with the required value of the engine control parameter as the steady optimum value;
Determining whether the constraint condition is satisfied when the response delay parameter varies within the variation region; and
When it is determined that the constraint condition is not satisfied, by correcting the steady-state optimum value of the response delay parameter, obtaining a conforming value of the response delay parameter;
It is characterized by including.

The third invention is the second invention, wherein
The engine control parameter includes an responsive parameter having better responsiveness than the response delay parameter,
The adaptation value acquiring step includes a step of optimizing the prompt response parameter so that fuel consumption is optimal after the adaptation value of the response delay parameter is obtained.

Moreover, 4th invention is set in 1st invention,
The engine control parameter includes an responsive parameter having better responsiveness than the response delay parameter,
In the adaptive value acquisition step, the A condition is satisfied so that the constraint condition is satisfied when the engine operating state shifts between a predetermined point A and a point B with a response delay of the response delay parameter. And calculating a response value of the response delay parameter and the quick response parameter at point B and point B.

The fifth invention is the first invention, wherein
The adaptive value acquisition step includes a step of obtaining an adaptive value of the response delay parameter using a prediction formula obtained by adding an increment due to the response delay of the response delay parameter to a response surface function of the predetermined engine characteristic value. It is characterized by.

The sixth invention is the first invention, wherein
The adaptive value acquisition step includes
Obtaining a higher-order response surface function having the engine control parameter, the engine speed and the engine load as explanatory variables, and the predetermined engine characteristic value as an objective variable;
Obtaining an adaptive value of the engine control parameter so that a value of an expression obtained by partial differentiation of the high-order response surface function with engine load is minimized;
It is characterized by including.

The seventh invention is a method for adapting a plurality of engine control parameters including a response delay parameter that is likely to cause a response delay.
A data acquisition step for measuring engine characteristic data when the engine is in steady operation;
Based on the engine characteristic data, for a plurality of engine characteristic values, a response surface function obtaining step for obtaining a response surface function having the engine control parameter as an explanatory variable and each engine characteristic value as an objective variable;
A fitness value acquisition step for obtaining a fitness value of the engine control parameter using an evaluation function obtained by multiplying each of the response surface functions for the plurality of engine characteristic values by a weighting factor and adding the function,
It is characterized by providing.

The eighth invention is an apparatus for adapting a plurality of engine control parameters including a response delay parameter in which a response delay is likely to occur.
Data acquisition means for measuring engine characteristic data when the engine is in steady operation;
A response surface function obtaining means for obtaining a response surface function having the engine control parameter as an explanatory variable and the engine characteristic value as an objective variable based on the engine characteristic data;
The engine control parameter is set so that a predetermined engine characteristic value satisfies a predetermined constraint when it is assumed that a response delay occurs in the response delay parameter in accordance with a change in the engine load and / or the rotational speed. A fitness value obtaining means for obtaining a fitness value using the response surface function;
It is characterized by providing.

The ninth invention is an apparatus for adapting a plurality of engine control parameters including a response delay parameter in which a response delay is likely to occur.
Data acquisition means for measuring engine characteristic data when the engine is in steady operation;
Response surface function acquisition means for obtaining a plurality of response surface functions having the engine control parameter as an explanatory variable and the engine characteristic value as an objective variable for a plurality of engine characteristic values based on the engine characteristic data;
Using an evaluation function obtained by multiplying each of the response surface functions for the plurality of engine characteristic values by multiplying by a weighting factor, and using the evaluation function, a suitable value obtaining means for obtaining a suitable value of the engine control parameter;
It is characterized by providing.

  According to the first aspect of the present invention, the engine control parameter adaptive value can be calculated so that the predetermined engine characteristic value satisfies the constraint condition in consideration of the response delay of the response delay parameter during transient operation. . As a result, engine control parameters can be adapted so that characteristics such as drivability are prevented from deteriorating during transient operation and characteristics such as fuel efficiency can be sufficiently improved.

  According to the second aspect of the invention, the adaptive value can be calculated by correcting the steady optimal value of the engine control parameter as necessary so that the constraint condition during the transient operation is satisfied. As a result, the engine control parameter adaptation value can be set to a value that is as close as possible to the steady optimum value within a range that can satisfy the constraint conditions during transient operation. For this reason, it can suppress more reliably that characteristics, such as drivability, deteriorate at the time of a transient driving | operation, and characteristics, such as a fuel consumption, can fully be improved.

  According to the third aspect of the present invention, the quick response parameter can be optimized so that the fuel consumption is optimal after obtaining the adaptive value of the response delay parameter. Thereby, fuel consumption can be improved to the maximum while surely suppressing deterioration of characteristics during transient operation.

  According to the fourth aspect of the invention, the response delay parameter and the quick response parameter are adjusted so that the deterioration of characteristics such as drivability during transient operation can be reliably suppressed and the characteristics such as fuel consumption can be sufficiently improved. Can be calculated.

  According to the fifth aspect of the present invention, it is possible to surely suppress deterioration of characteristics such as drivability during transient operation and to calculate an appropriate value of the engine control parameter so that characteristics such as fuel consumption can be sufficiently improved. Can do. In addition, the calculation of the fitness value is easy, the processing time can be shortened, and systemization is easy.

  According to the sixth aspect of the invention, the adaptive value of the engine control parameter is calculated so as to reliably suppress the deterioration of characteristics such as drivability during transient operation and to sufficiently improve characteristics such as fuel consumption. Can do.

  According to the seventh aspect, it is possible to obtain the adaptive value of the engine control parameter by using the evaluation function obtained by multiplying each of the response surface functions for the plurality of engine characteristic values by the weighting coefficient and adding it. As a result, a plurality of engine characteristic values can be considered in a balanced manner as compared with a case where a matching value is obtained by simply applying a constraint value to the engine characteristic value. For this reason, excellent robustness can be obtained. Therefore, it is possible to calculate an appropriate value of the engine control parameter so as to reliably suppress the deterioration of the drivability characteristic during the transient operation and sufficiently improve the characteristics such as fuel consumption.

  According to the eighth aspect of the invention, it is possible to calculate the adaptive value of the engine control parameter so that the predetermined engine characteristic value satisfies the constraint condition in consideration of the response delay of the response delay parameter during the transient operation. . As a result, engine control parameters can be adapted so that characteristics such as drivability are prevented from deteriorating during transient operation and characteristics such as fuel efficiency can be sufficiently improved.

  According to the ninth aspect, it is possible to obtain the adaptive value of the engine control parameter using the evaluation function obtained by multiplying each of the response surface functions for the plurality of engine characteristic values by the weighting coefficient and adding the result. As a result, a plurality of engine characteristic values can be considered in a balanced manner as compared with a case where a matching value is obtained by simply applying a constraint value to the engine characteristic value. As a result, excellent robustness can be obtained, so that it is possible to reliably suppress deterioration of characteristics such as drivability during transient operation, and to sufficiently improve characteristics such as fuel efficiency, and so on. Can be calculated.

Embodiment 1 FIG.
[Description of system configuration]
FIG. 1 is a diagram showing a configuration of an engine control parameter adaptation apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1, the engine 10 is arranged above a cylinder 11, a piston 12, a combustion chamber 13 defined by the cylinder 11 and the piston 12, an injector 14 that directly injects fuel, and a combustion chamber 13. And an ignition plug 15 for igniting the air-fuel mixture. In the present embodiment, the ignition timing by the spark plug 15 is represented by the symbol ST. In the present invention, unlike the illustrated configuration, the injector 14 may be provided so as to inject fuel into the intake port.

  Air is sucked into the combustion chamber 13 from the intake passage 16, and fuel is injected into this to become an air-fuel mixture. Combustion gas in which the air-fuel mixture is combusted by ignition is discharged from the combustion chamber 13 to the exhaust passage 17 as exhaust. Each timing of intake of air from the intake passage 16 and discharge of exhaust to the exhaust passage 17 is set by opening timings of the intake valve 18 and the exhaust valve 19, respectively. In the case of the engine 10 shown in FIG. 1, the valve timing of the intake valve 18 is continuously and variably set by a variable valve timing mechanism 20. In the present embodiment, the control parameter (for example, the advance amount) of the variable valve timing mechanism 20 is represented by the symbol VVT. Although not shown, the engine 10 may further be provided with a mechanism that makes the valve timing of the exhaust valve 19 variable.

  On the other hand, the amount of air taken into the combustion chamber 13 of the engine 10 is adjusted by an electronically controlled throttle 21 provided in the intake passage 16. Further, in the engine 10, EGR (Exhaust Gas Recirculation) in which a part of the exhaust gas discharged to the exhaust passage 17 is returned to the intake passage 16 via the EGR passage 22 can be executed. The exhaust amount to be returned, that is, the EGR amount is adjusted by the valve opening amount of the EGR valve 23.

  Such control of the engine 10 is performed by the ECU 30. In addition, information from various sensors that measure the operating state of the engine, such as the water temperature sensor 26 and the crank angle sensor 25 provided in the vicinity of the crankshaft 24 of the engine 10, is input to the ECU 30 as measurement information.

  The adaptation device of this embodiment calculates each adaptation value of a control map that sets various control parameters of the engine 10 to appropriate values. The adapting device of this embodiment includes a dynamometer 31 connected to the crankshaft 24 of the engine 10, a dynamometer operation panel 32 for operating the dynamometer 31, and a dynamometer operation panel 32 for controlling the dynamometer 31 to predetermined conditions. And an automatic measuring device 33 for sending a command to the computer.

  Here, the dynamometer 31 absorbs torque generated by the crankshaft 24 of the engine 10. As a result, various tests can be performed with the engine 10 mounted in a pseudo state on the vehicle. Then, the torque absorbed by the dynamometer 31 is controlled by operating the dynamo operation panel 32 in accordance with a command from the automatic measuring device 33.

  The adaptation apparatus of the present embodiment further includes a panel checker 34 that mediates data exchange between the ECU 30 and the automatic measurement apparatus 33. Then, the automatic measuring device 33 acquires measurement information of the engine 10 held in the ECU 30 via the panel checker 34.

  When the engine 10 is actually mounted on a vehicle, the driving state is controlled based on measurement information input to the ECU 30 from various sensors or the like. On the other hand, when the dynamometer 31 is used to create a state of being mounted on the vehicle in a pseudo manner, data such as the accelerator pedal depression amount reflecting the driver's will is not supplied to the ECU 30.

  Accordingly, the automatic measuring device 33 supplies the ECU 30 with data corresponding to the amount of depression of the accelerator pedal via the panel checker 34 while monitoring the state of the engine 10 with reference to the measurement information of the engine 10. In this way, the automatic measuring device 33 controls the engine 10 to a desired operating state.

  On the other hand, in the ECU 30, a control map that can roughly control the engine 10 such as a control map of an engine of a model similar to the engine 10 is stored as control information of the engine 10.

  A command for controlling the engine 10 and the dynamometer 31 by the automatic measuring device 33 is largely set based on a condition file in the automatic measuring device 33. The condition file basically includes control parameters (ignition timing ST, fuel injection amount, valve timing VVT, EGR rate, fuel) for each operating state (rotation speed and load) of the engine 10 desired to be measured. Injection timing, fuel pressure, etc.) are written. The engine 10 is fixedly controlled for each operating state, and the output of the engine 10 at that time is measured by the measuring device 35. Each condition set in the condition file is set by the condition setting tool 53.

  In order to control the operation state of the engine 10 to each operation state set in the condition file, the automatic measuring device 33 supplies data corresponding to the depression amount of the accelerator pedal to the ECU 30 via the panel checker 34.

  When the engine 10 is controlled to the operation state set through this condition file, the automatic measuring device 33 sets a manual flag in a memory or a register in the ECU 30 via the panel checker 34. This manual flag is a flag for prohibiting the control of the engine 10 by the control map.

  When the engine 10 enters the operation state set through the condition file, the automatic measuring device 33 sets this flag and controls the control parameter of the engine 10 to a value set in the condition file.

  With the control parameters fixedly controlled to predetermined control values based on the engine operating conditions set in the above condition file, the engine 10 such as the fuel consumption rate BSFC, the NOx concentration in the exhaust, the output torque fluctuation amount TF, etc. Each characteristic value is measured by the measuring device 35.

  Specifically, the measuring device 35 includes a fuel consumption meter that measures the amount of fuel supplied to the engine 10, an analyzer that analyzes the NOx concentration in the gas component discharged from the exhaust passage 17 of the engine 10, and the engine 10. And a torque meter installed between the dynamometers 31 and a torque fluctuation meter for calculating the value of the torque meter.

  And regarding the fuel consumption rate BSFC, the measurement value by the fuel consumption meter is calculated in the automatic measuring device 33. The NOx concentration is calculated by the automatic measuring device 33 using the concentration calculated by the analyzer as a measured value. Further, the torque fluctuation TF is measured as a value of a torque fluctuation meter, and is calculated by the automatic measuring device 33. Data calculated in the automatic measuring device 33 becomes measurement data.

  The adaptive apparatus further includes a server 40 that holds measurement data for each condition file, an analysis tool 50 that analyzes the measurement data held in the server 40 together with information about each condition file, and an analysis result by the analysis tool 50. Is displayed, a database 52 for storing and holding a part of the analysis result, and an operation unit 60 for operating the analysis tool 50, the condition setting tool 53, and the like.

[Specific Processing in Embodiment 1]
FIG. 2 is a flowchart of the engine control parameter adaptation method according to this embodiment, which is executed by the adaptation apparatus described above. In the present embodiment, a two-dimensional operation region determined by the rotational speed and load of the engine 10 is divided into a grid, and the engine control parameter adaptation value at each grid point (for example, 120 points) is calculated.

  The variable valve timing mechanism 20 of the engine 10 includes a hydraulic actuator or an electric motor, and changes the valve timing VVT by operating the hydraulic actuator or the electric motor. Therefore, it takes some time to change the valve timing VVT. For this reason, a response delay of the variable valve timing mechanism 20 is likely to occur during a transient operation in which the required value (target value) of the valve timing VVT changes with time. As described below, according to the adaptation method of the present embodiment, even when a response delay of the variable valve timing mechanism 20 occurs, it is possible to reliably prevent deterioration of characteristics such as torque fluctuations, An appropriate value of the engine control parameter can be calculated so that the fuel efficiency improvement effect by varying the valve timing VVT can be sufficiently obtained.

  As shown in FIG. 2, in the adaptation method of the present embodiment, first, a steady operation test of the engine 10 is performed according to an experiment plan set by a technique such as an experiment design method, and the engine characteristic data measured in this test is obtained. Based on this, a characteristic prediction formula (response surface function) is calculated (step 100).

  That is, in this step 100, first, several engine control parameter values are set for each grid point, and various engine characteristic values are measured. Based on these measurement results, a response surface function is obtained for each grid point with each control parameter as an explanatory variable and each engine characteristic value as an objective variable.

  In the present embodiment, the characteristic values to be measured are the fuel consumption rate BSFC, the torque fluctuation TF, the exhaust gas temperature, the NOx emission amount, the exhaust gas sensor temperature, and the like. The engine control parameters include the ignition timing ST and the valve timing VVT.

The model expression of the response surface function can be expressed by, for example, a constant term, a primary term of each control parameter, a quadratic term, and an interaction term of two control parameters. For example, the torque fluctuation TF is expressed by the following equation.
TF = β ₀ + β ₁ × VVT + β ₂ × ST + β ₃ × VVT ² + β ₄ × ST ² + β ₅ × VVT × ST

Each coefficient β _{0 to} β ₅ in the above formula is determined by performing multiple regression analysis based on torque fluctuation data measured in the steady operation test. As a result, a response surface function of the torque fluctuation TF is obtained. Similarly, response surface functions can be obtained for other engine characteristic values.

  Following the processing of step 100, the optimum values (hereinafter referred to as “steady optimum values”) of the control parameters (ignition timing ST and valve timing VVT) during steady operation of the engine 10 are calculated for each grid point. (Step 102). In this embodiment, in this step 102, combinations of control parameters that minimize the fuel consumption rate BSFC within a range in which the torque fluctuation TF, the exhaust gas temperature, the NOx emission amount, and the exhaust gas sensor temperature satisfy predetermined constraint conditions, respectively. Is calculated as a steady-state optimum value. As an optimization method at this time, for example, a steepest descent method, an annealing method, a genetic algorithm, or the like can be used.

  Note that the processing in steps 100 and 102 described above is described in, for example, Japanese Patent Application Laid-Open No. 2004-68729, Japanese Patent Application Laid-Open No. 2005-42656, Japanese Patent Application Laid-Open No. 2006-17698, and the like. Then, further explanation is omitted.

  Further, according to the routine shown in FIG. 2, a sufficient number of characteristic prediction formulas (response surface functions) in the operation region affected by the response delay of the variable valve timing mechanism 20 are acquired following the processing of step 100 described above. It is determined whether or not there is (step 104). When it is determined that the characteristic prediction formula is not sufficient, necessary experiment data is secured by performing an additional experiment or the like (step 106), and the characteristic prediction formula is replenished based on the additional experiment data. The

  Subsequent to the above processing, based on the response delay characteristic of the variable valve timing mechanism 20, the fluctuation regions in the load direction and the rotational speed direction of the engine 10 are set (step 108). FIG. 3 is a diagram for explaining an example of a technique for setting a load direction fluctuation region. In the example shown in FIG. 3, the throttle opening is reduced so that the load factor changes from 50% to 30%. The intake air amount follows the change in the throttle opening with a delay. As the intake air amount (load factor) changes, the required value (target value) of the valve timing VVT changes. The VVT request value here is tentatively the steady optimum value calculated in step 102 above. The actual valve timing VVT follows the change in the VVT request value with a delay. ΔVVT in FIG. 3 is a difference between the actual VVT and the VVT request value. In the example shown in FIG. 3, ΔVVT varies in the range of 0-9. Therefore, in this example, the VVT fluctuation region (fluctuation range) is set to 0-9.

  Although the method for setting the VVT fluctuation region when the load on the engine 10 changes has been described with reference to FIG. 3, the VVT fluctuation region when the engine 10 changes in speed can be set similarly.

  Following the processing of step 108, when the actual VVT fluctuates within the fluctuating region, an adaptive value of VVT is obtained so that the torque fluctuation TF is not more than the constraint value at the time of transition (step 110). FIG. 4 is a diagram for explaining a specific example of the processing of step 110 described above. In FIG. 4, the lower graph is a response surface function of torque fluctuation TF at light load, the middle graph is a response surface function of torque fluctuation TF at medium load, and the upper graph is the response of fuel consumption rate BSFC. It is a surface function. The horizontal axis represents the ignition timing ST.

  In the graph of each stage of FIG. 4, the response surface function is drawn as a cross section at three different VVT values. In the graph of torque fluctuation TF at light load (lower graph), the leftmost curve is a response surface function when the VVT value is a steady optimum value at light load. On this curve, the ignition timing ST at which the torque fluctuation TF is less than or equal to the steady-state constraint value and the fuel consumption rate BSFC is minimum is a point indicated by a double circle in the drawing. Therefore, this point is the steady optimum ignition timing at light load.

  On the other hand, in the graph of the torque fluctuation TF at the middle load (middle graph), the rightmost curve is a response surface function when the VVT value is a steady optimum value at the middle load. On this curve, the ignition timing ST at which the torque fluctuation TF is equal to or less than the constraint value at the steady state and the fuel consumption rate BSFC is minimum is a point indicated by a black circle in the drawing. Therefore, this point is the steady optimum ignition timing at the time of medium load.

  Next, a description will be given of a transient case where acceleration is performed from the state where the engine 10 is in steady operation at the steady optimum point at the time of light load indicated by the double circle and the transition to the middle load region is performed. In this case, considering the VVT fluctuation region (response delay) set in step 110, the operating point of the engine 10 is a single circle in the middle graph as shown by the arrow in the figure from the double circle. Migrate to The torque fluctuation TF at this single circle point is equal to or less than the constraint value at the time of transition. Therefore, in this example, it can be determined that there is no problem at the time of transition even when the optimum values of the valve timing VVT and the ignition timing ST at the time of light load are set to the steady optimum points indicated by the double circles.

  On the other hand, when the engine 10 is decelerating from a state where the engine 10 is in steady operation at the steady optimum point at the time of medium load indicated by the black circle, a transition is made as follows in a transition to a light load region. Considering the VVT fluctuation region (response delay) set in step 110, the operating point of the engine 10 shifts from the black circle as shown by the arrow in the figure as shown in FIG. On this transition destination curve (the rightmost curve in the lower graph), the torque fluctuation TF cannot be made equal to or less than the constraint value at the time of transition no matter how the ignition timing ST is controlled. Therefore, in this case, assuming that the optimum values of the valve timing VVT and the ignition timing ST at the time of medium load are the steady optimum points indicated by the black circles, the torque fluctuation TF has a constraint value (allowable value) in the light load region during deceleration. It can be judged that it will exceed.

  In the present embodiment, in the above case, that is, when it is determined that the torque fluctuation TF exceeds the constraint value at the time of transition, the VVT request value is corrected so that the operating range of the variable valve timing mechanism 20 becomes smaller. Then, the VVT fluctuation region is calculated again by the same procedure as in FIG. That is, the VVT request value is reset so that the VVT fluctuation region becomes smaller. Then, in the corrected VVT fluctuation region, it is confirmed whether or not the torque fluctuation TF at the time of transition is less than or equal to the constraint value.

  Returning to the example shown in FIG. 4, the dashed curve in the middle graph is a response surface function of the torque fluctuation TF when the VVT required value at the time of medium load is corrected. In the case of a transition in which the engine 10 is decelerated from the state in which the engine 10 is normally operated with the modified VVT value and then shifts to the light load region, the operating point of the engine 10 is indicated by a double circle in the middle graph. Transition as indicated by the arrow in the middle. That is, the torque fluctuation TF in this case is represented by a broken line curve in the lower graph in consideration of the corrected VVT fluctuation region. Therefore, it is understood that the torque fluctuation TF can be made to be equal to or less than the constraint value at the time of transition by controlling the ignition timing ST indicated by a single circle on the dashed curve. Therefore, at the time of medium load, the torque fluctuation TF at the time of transition can be surely suppressed below the constraint value by setting the corrected VVT request value to a value suitable for the valve timing VVT.

  If the torque fluctuation TF during the transition does not fall below the constraint value even in the corrected VVT request value, the VVT request value may be corrected again and the same procedure may be repeated. In step 110 described above, the above procedure is repeated while shifting the target operation region, thereby obtaining the appropriate value of the valve timing VVT in the entire operation region.

  According to the routine shown in FIG. 2, when the VVT conformity value in all the operation regions (each grid point) is determined in step 110, the fuel consumption rate BSFC is then minimized under the VVT conformance value. In addition, a suitable value for the ignition timing ST is determined for each grid point (step 112). Thereby, the fuel consumption performance of the engine 10 can be further improved.

  FIG. 5 is a map showing the VVT conformance value obtained in step 110. As shown in FIG. 5, according to the present embodiment, when setting a suitable value of VVT, within a range in which the torque fluctuation TF at the time of transition can be suppressed to a constraint value or less for each region, and steady optimum The VVT conforming value can be set to a value as close as possible. That is, the VVT conforming value can be set so that the torque fluctuation TF at the time of transition is surely suppressed to a value equal to or less than the constraint value, and the fuel consumption improvement effect by the variable valve timing mechanism 20 is obtained to the maximum. Therefore, both drivability and fuel efficiency can be improved.

  Furthermore, according to the present embodiment, by executing the processing as described above in the adaptation device shown in FIG. 1, the adaptation value of the control parameter at each grid point can be automatically calculated. For this reason, engine development efficiency can be remarkably improved.

  In the first embodiment described above, the torque fluctuation TF is the “predetermined engine characteristic value” in the first and eighth inventions, and the valve timing VVT is the “response delay parameter” in the first and eighth inventions. The ignition timing ST is the “immediate response parameter” in the third invention, the step 100 is the “data acquisition step” and the “response surface function acquisition step” in the first invention, and the steps 102, 108 and 110 are This corresponds to the “adapted value acquisition step” in the first invention. In addition, when the adaptive device executes the process of step 100, the “data acquisition means” and the “response surface function acquisition means” in the eighth invention execute the processes of steps 102, 108, and 110. As a result, the “adapted value acquisition means” according to the eighth aspect of the present invention is realized.

  In the present embodiment, the case where the response delay of the variable valve timing mechanism 20 during the transition is dealt with has been mainly described. However, the present invention is not limited to various other control devices (for example, the variable valve timing mechanism of the exhaust valve 19). The present invention can be similarly applied to a case where response delay of an external EGR device or the like is dealt with.

Embodiment 2. FIG.
Next, the second embodiment of the present invention will be described with reference to FIG. 6. The description will focus on the differences from the first embodiment described above, and the same matters will be simplified or described. Omitted. The present embodiment can be realized using the system shown in FIG. 1 similar to the first embodiment.

  In the present embodiment, when the operating point of the engine 10 shifts between point A and point B at the time of acceleration / deceleration of the engine 10, the ignition timing ST is changed to the control value of the transfer destination. The valve timing VVT and the ignition timing ST are adapted so that the torque fluctuation does not exceed the constraint value even when the valve timing VVT remains at the control value at the original operating point due to a response delay. Calculate the value.

  Hereinafter, the calculation method of the conformity value of the valve timing VVT and the ignition timing ST in the present embodiment will be specifically described based on the example of FIG. FIG. 6 is a view substantially similar to FIG. 4 of the first embodiment described above. In FIG. 6, A is a response surface function of the torque fluctuation TF when the VVT is controlled to an appropriate value at light load. Here, it is assumed that the VVT remains at a value suitable for a light load when accelerating to a middle load range. In this case, the response surface function of the torque fluctuation TF is a curve indicated by B in the middle graph. A point on the curve B where the torque fluctuation TF is less than or equal to the constraint value at the time of transition is C in the figure. Therefore, the appropriate value of the ignition timing ST at the time of medium load is determined as D in the figure.

  Next, the valve timing VVT is calculated so that the fuel consumption rate BSFC decreases when the ignition timing ST is at the above point D at the time of medium load. The response surface function that decreases the fuel consumption rate BSFC when the ignition timing ST is at point D is represented by a curve indicated by E in the upper graph. Therefore, the VVT value at this time is determined as the VVT compatible value at the time of medium load. A curve indicated by F in the middle graph is a response surface function of the torque fluctuation TF in the case of the VVT conforming value. That is, the point G in the figure is a suitable value for the ignition timing ST and the valve timing VVT at the time of medium load.

  Next, consider a case where the vehicle is decelerated from the point G to a light load range. In this case, assuming that VVT remains a value suitable for medium load, the response surface function of torque fluctuation TF is a curve indicated by H in the lower graph. A point on the curve H where the torque fluctuation TF is not more than the constraint value at the time of transition is I in the figure. Therefore, the suitable value of the ignition timing ST at the time of light load is determined as the point J in the figure.

  In the present embodiment, the adaptive values of the valve timing VVT and the ignition timing ST are calculated by sequentially performing the above-described procedure from the light load range to the high load range. Thereby, the same effect as Embodiment 1 is acquired.

  In the second embodiment described above, the ignition timing ST corresponds to the “immediate response parameter” in the fourth invention.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described with reference to FIG. 7. The description will focus on the differences from the first embodiment described above, and the same matters will be simplified or described. Omitted. The present embodiment can be realized using the system shown in FIG. 1 similar to the first embodiment.

  In the present embodiment, in calculating the adaptive value of the valve timing VVT, a prediction formula is obtained by adding an increment due to the response delay of VVT to the response surface function of the torque fluctuation TF. Then, an adaptive value of VVT is calculated so that the torque fluctuation TF at the time of transition calculated by the prediction formula is equal to or less than the constraint value.

Here, the response surface function of the torque fluctuation TF is represented by a function f as in the following equation.
TF = f (VVT, ST)

When the torque fluctuation at the time of transition is TF ′ and the VVT delay amount is 5 degrees, for example, the prediction formula of the torque fluctuation TF ′ at the time of transition is expressed by the following expression.
TF ′ = f (VVT, ST) + | {∂f / ∂VVT} × 5 deg |

  The above relationship is illustrated in FIG. In the present embodiment, a point (A in FIG. 7) at which the torque fluctuation TF ′ during the transition is equal to or less than the constraint value is determined as the VVT conforming value.

  According to the adaptation method of the present embodiment described above, the same effects as those of the first embodiment can be obtained. Further, since the response surface function f of the torque fluctuation TF has already been obtained as a function of VVT and ST, a term obtained by partial differentiation with respect to VVT can be easily obtained. For this reason, the calculation of the fitness value is easy, the processing time can be shortened, and systemization is easy. Further, when other response delay devices such as the variable valve timing mechanism of the exhaust valve 19 and the EGR device need to be taken into consideration, a term obtained by partially differentiating the response surface function f with these control parameters is used in the above prediction formula. Furthermore, it is sufficient to add, and the extensibility of the system is excellent.

Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described with reference to FIG. 8. The description will focus on the differences from the first embodiment described above, and the same matters will be simplified or described. Omitted. The present embodiment can be realized using the system shown in FIG. 1 similar to the first embodiment.

In the above-described embodiment, the response surface function of the torque fluctuation TF is expressed using the valve timing VVT and the ignition timing ST as parameters. On the other hand, in the present embodiment, the torque fluctuation TF is expressed as a high-order response surface function in which the engine speed (represented by the symbol NE) and the load (represented by the symbol KL) are also added to the parameters. That is, the following formula is calculated.
TF = α ₀ + α ₁ × VVT + α ₂ × ST + α ₃ × NE + α ₄ × KL + α ₅ × VVT ²
+ Α ₆ × ST ² + α ₇ × NE ² + α ₈ × KL ² + α ₉ × VVT × ST +
+ Α _p × VVT × KL ++ α _q × ST × KL + α _x × NE × KL

When the above high-order response surface function is partially differentiated with the load KL, the following equation is obtained.
∂TF / ∂KL = α ₄ × KL + 2 × α ₈ × KL + α _p × VVT + α _q × ST + α _x × NE

  In general, the greater the change in the torque fluctuation TF with respect to the change in each control parameter, the worse the drivability is. For this reason, in order to improve the drivability at the time of transition, it is preferable to make the change of the torque fluctuation TF with respect to the change of each control parameter as small as possible. Therefore, in the present embodiment, the control parameter adaptation value is calculated so that the coefficient when the control parameters are normalized in the target region is large and the value of ∂TF / ∂KL is minimized. It was.

  Here, the normalization of the control parameter means, for example, that any parameter can be compared with a region where the VVT is changed from 0 to 30 and a region where the engine speed NE is changed from 1000 rpm to 2000 rpm. It means non-dimensionalization so that the average value changes from −1 to 1 and the change becomes 1.

  Hereinafter, the example shown in FIG. 8 will be described. In the example shown in FIG. 8, the change rate of the torque fluctuation TF with respect to the change of the engine speed NE is always constant. For this reason, the partial differential coefficient for NE is small. On the other hand, the change rate of the torque fluctuation TF with respect to the change of the ignition timing ST changes greatly from minus to plus. Therefore, in this example, in order to suppress the change of the torque fluctuation TF due to the change of the ignition timing ST, the point of ST = −0.5 where the change of the torque fluctuation TF with respect to the change of the ignition timing ST becomes zero is set as the appropriate value. decide.

  If the appropriate value of the ignition timing ST is calculated as described above, the appropriate value of VVT is then calculated so that the value of ∂TF / ∂KL is minimized. According to the adaptation method of this embodiment, the same effect as that of Embodiment 1 can be obtained.

Embodiment 5 FIG.
Next, the fifth embodiment of the present invention will be described with reference to FIG. 9 and FIG. 10. The description will focus on the differences from the first embodiment described above, and the same matters will be described. Simplify or omit. The present embodiment can be realized using the system shown in FIG. 1 similar to the first embodiment.

  The present embodiment is characterized in that an adaptive value of an engine control parameter is obtained by using an evaluation function obtained by multiplying each of response surface functions for a plurality of engine characteristic values by a weighting factor and adding them.

  Incidentally, as described above, the engine 10 shown in FIG. 1 can execute so-called external EGR in which a part of the exhaust gas discharged to the exhaust passage 17 is returned to the intake passage 16 via the EGR passage 22. . This EGR control parameter (hereinafter referred to as EGR rate) is adjusted by the valve opening amount of the EGR valve 23 or the like. However, since EGR gas recirculates into the combustion chamber 13 through the EGR passage 22 and the intake passage 16, a transport delay occurs. For this reason, an EGR response delay is likely to occur during transient operation.

  The present embodiment can be particularly suitably applied when considering the response delay of the external EGR as described above in addition to the response delay of the variable valve timing mechanism 20.

  Hereinafter, before explaining the engine control parameter adaptation method of the present embodiment, a comparison example adaptation method will be described with reference to FIG. 9 in order to facilitate understanding. FIG. 9 shows response surface functions of the torque fluctuation TF and the fuel consumption rate BSFC. In FIG. 9, as the control parameter increases, the torque fluctuation TF increases monotonously and the fuel consumption rate BSFC decreases monotonously. That is, in this example, it is preferable that the control parameter is small from the viewpoint of the torque fluctuation TF, while it is preferable that the control parameter is large from the viewpoint of the fuel consumption rate BSFC. Therefore, in this case, the constraint condition is that the torque fluctuation TF is suppressed to a certain constraint value or less. Therefore, the region where the torque fluctuation TF exceeds the constraint value (the hatched portion in FIG. 9) is not allowed, and the point where the fuel consumption rate BSFC is minimum in the other regions is determined as the appropriate value.

On the other hand, FIG. 10 is a figure for demonstrating the adaptation method of this embodiment. FIG. 10 shows a response surface function of the intake air temperature rise T _{air in} addition to the response surface function of the fuel consumption rate BSFC. In FIG. 10, as the control parameter (for example, EGR rate) increases, the fuel consumption rate BSFC monotonously decreases, and the intake air temperature increase T _air monotonously increases. If the intake air temperature becomes too high, knocking is likely to occur. For this reason, in order to reliably prevent knocking, it is preferable that the intake air temperature increase T _air be as small as possible. Therefore, in this example, it is preferable that the control parameter is large from the viewpoint of the fuel consumption rate BSFC, while it is preferable that the control parameter is small from the viewpoint of the intake air temperature increase T _air .

In the case shown in FIG. 10 described above, if the restriction condition is that the intake air temperature increase T _{air is set} to a certain constraint value (upper limit value at which knocking can be avoided) or less, there is the following concern. As described above, there is a response delay in EGR. If the control parameter shifts in a direction larger than the conforming value due to a response delay at the time of transition, the intake air temperature rise T _air will exceed the constraint value, which increases the possibility of knocking. .

In the present embodiment, in order to increase the robustness and reliably avoid the above-described concerns, the conformity value is calculated as follows. That is, after multiplying the response surface function of the fuel consumption rate BSFC and the response surface function of the intake air temperature rise T _air by weighting factors (in the example of FIG. 10, both are 0.5), An evaluation function Fanc obtained by addition is created. Then, the control parameter value when the evaluation function Fanc becomes the minimum is determined as the fitness value. According to such a method, by appropriately setting each of the weighting factors described above, a plurality of engine characteristic values (here, fuel consumption rate BSFC and intake air temperature increase T _air ) are considered in a well-balanced manner, and an appropriate value is determined. Can be determined. For this reason, robustness at the time of transient operation can be improved, and both drivability and fuel consumption can be improved.

It is a figure which shows the structure of the adaptation apparatus of the engine control parameter of Embodiment 1 of this invention. It is a flowchart of the routine performed in Embodiment 1 of the present invention. It is a figure for demonstrating the method of setting the fluctuation area | region of a load direction. It is a figure for demonstrating the adaptation method of Embodiment 1 of this invention. It is a map which shows the adaptation value calculated by the adaptation method of Embodiment 1 of this invention. It is a figure for demonstrating the adaptation method of Embodiment 2 of this invention. It is a figure for demonstrating the adaptation method of Embodiment 3 of this invention. It is a figure for demonstrating the adaptation method of Embodiment 4 of this invention. It is a figure for demonstrating the adaptation method of the comparative example with respect to Embodiment 5 of this invention. It is a figure for demonstrating the adaptation method of Embodiment 5 of this invention.

Explanation of symbols

10 Engine 11 Cylinder 12 Piston 13 Combustion chamber 14 Injector 15 Spark plug 16 Intake passage 17 Exhaust passage 18 Intake valve 19 Exhaust valve 20 Variable valve timing mechanism 21 Electronic control throttle 22 EGR passage 23 EGR valve 24 Crankshaft 25 Crank angle sensor 26 Water temperature Sensor

Claims (9)

A method of adapting a plurality of engine control parameters including a response delay parameter in which response delay is likely to occur,
A data acquisition step for measuring engine characteristic data when the engine is in steady operation;
A response surface function obtaining step for obtaining a response surface function having the engine control parameter as an explanatory variable and the engine characteristic value as an objective variable based on the engine characteristic data;
The engine control parameter is set so that a predetermined engine characteristic value satisfies a predetermined constraint when it is assumed that a response delay occurs in the response delay parameter in accordance with a change in the engine load and / or the rotational speed. A fitness value obtaining step for obtaining a fitness value using the response surface function;
A method for adapting engine control parameters, comprising: The adaptive value acquisition step includes
Using the response surface function, obtaining a steady optimum value that is an optimum value of the engine control parameter during steady operation;
Obtaining a fluctuation region of the response delay parameter when the engine load and / or the number of revolutions is changed with the required value of the engine control parameter as the steady optimum value;
Determining whether the constraint condition is satisfied when the response delay parameter varies within the variation region; and
When it is determined that the constraint condition is not satisfied, by correcting the steady-state optimum value of the response delay parameter, obtaining a conforming value of the response delay parameter;
A method for adapting engine control parameters, comprising: The engine control parameter includes an responsive parameter having better responsiveness than the response delay parameter,
3. The engine control parameter according to claim 2, wherein the adaptive value acquisition step includes a step of optimizing the quick response parameter so that fuel consumption is optimal after an adaptive value of the response delay parameter is obtained. How to fit. The engine control parameter includes an responsive parameter having better responsiveness than the response delay parameter,
In the adaptive value acquisition step, the A condition is satisfied so that the constraint condition is satisfied when the engine operating state shifts between a predetermined point A and a point B with a response delay of the response delay parameter. 2. The engine control parameter adaptation method according to claim 1, further comprising a step of obtaining an adaptation value of the response delay parameter and the quick response parameter at the point and the point B.   The adaptive value acquisition step includes a step of obtaining an adaptive value of the response delay parameter using a prediction formula obtained by adding an increment due to the response delay of the response delay parameter to a response surface function of the predetermined engine characteristic value. The method for adapting engine control parameters according to claim 1. The adaptive value acquisition step includes
Obtaining a higher-order response surface function having the engine control parameter, the engine speed and the engine load as explanatory variables, and the predetermined engine characteristic value as an objective variable;
Obtaining an adaptive value of the engine control parameter so that a value of an expression obtained by partial differentiation of the high-order response surface function with engine load is minimized;
The method for adapting engine control parameters according to claim 1, further comprising: A method of adapting a plurality of engine control parameters including a response delay parameter in which response delay is likely to occur,
A data acquisition step for measuring engine characteristic data when the engine is in steady operation;
Based on the engine characteristic data, for a plurality of engine characteristic values, a response surface function obtaining step for obtaining a response surface function having the engine control parameter as an explanatory variable and each engine characteristic value as an objective variable;
A fitness value acquisition step for obtaining a fitness value of the engine control parameter using an evaluation function obtained by multiplying each of the response surface functions for the plurality of engine characteristic values by a weighting factor and adding the function,
A method for adapting engine control parameters, comprising: A device that adapts a plurality of engine control parameters including a response delay parameter that is likely to cause a response delay,
Data acquisition means for measuring engine characteristic data when the engine is in steady operation;
A response surface function obtaining means for obtaining a response surface function having the engine control parameter as an explanatory variable and the engine characteristic value as an objective variable based on the engine characteristic data;
The engine control parameter is set so that a predetermined engine characteristic value satisfies a predetermined constraint when it is assumed that a response delay occurs in the response delay parameter in accordance with a change in the engine load and / or the rotational speed. A fitness value obtaining means for obtaining a fitness value using the response surface function;
An apparatus for adapting engine control parameters, comprising: A device that adapts a plurality of engine control parameters including a response delay parameter that is likely to cause a response delay,
Data acquisition means for measuring engine characteristic data when the engine is in steady operation;
Response surface function acquisition means for obtaining a plurality of response surface functions having the engine control parameter as an explanatory variable and the engine characteristic value as an objective variable for a plurality of engine characteristic values based on the engine characteristic data;
Using an evaluation function obtained by multiplying each of the response surface functions for the plurality of engine characteristic values by multiplying by a weighting factor, and using the evaluation function, a suitable value obtaining means for obtaining a suitable value of the engine control parameter;
An apparatus for adapting engine control parameters, comprising:

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