JP2012013637A - Adaptation method and adaptation device for engine control parameter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compatibly achieve both improvement in precision of an engine characteristic model used to adapt control parameters of an engine (improvement in precision of adaptation values of control parameters) and a decrease in man-hour.SOLUTION: A physical parameter is selected (101) for a control parameter to be adapted. When the control parameter to be adapted is a VCT lead angle value, one of an in-cylinder EGR rate, an in-cylinder flow velocity, intake air temperature, pumping loss, intake pipe pressure, and an actual compression ratio is selected as a physical parameter therefor, and when the control parameter to be adapted is an injection period, one of an atomized fuel movement distance, an atomization time, a vaporized fuel amount, and an atomization-time in-cylinder flow velocity is selected as a physical parameter therefor. Then relationship between the control parameter and the physical parameter is calculated with measurement data (102), a value of the control parameter at which a criterion of the physical parameter defining the border of an experimentation plan range of the control parameter is generated is calculated (103), and the experimentation plan range of the control parameter is determined (104).

Description

  The present invention relates to an engine control parameter adaptation method and an adaptation apparatus that determine an engine control parameter adaptation value using an engine characteristic model so that required engine performance is satisfied.

  Recent high-performance engines are equipped with various functions such as a variable valve timing mechanism and an EGR system to improve output, reduce exhaust emissions, and reduce fuel consumption. In addition to the ignition timing, not only the ignition timing but also the valve timing, the EGR rate, and the like need to be adapted, and the number of control parameters to be adapted has increased, and the adjustment work of the control parameters has become very troublesome.

  Therefore, as described in Patent Document 1 (Japanese Patent Laid-Open No. 2002-206456) and Patent Document 2 (Japanese Patent Laid-Open No. 2005-42656), the control parameter of the engine to be measured is changed to be a predetermined number. The engine characteristic value (physical parameter) is measured at the measurement points, and the engine characteristic model is created by modeling the relationship between each control parameter and the engine characteristic value based on the measurement result. Using this engine characteristic model Some control parameters are adapted to be calculated.

  However, in the techniques of Patent Documents 1 and 2, the measurement point for changing the control parameter of the engine is not necessarily arranged in the stable combustion region, and may be arranged in the combustion deterioration region. Then, misfire, unstable combustion, and abnormal combustion may damage the engine. If a measurement point is placed in the combustion deterioration area, the measurement accuracy of the measurement point deteriorates or becomes impossible to measure, so the accuracy of the engine characteristic model deteriorates and the control parameter calculated using the engine characteristic model The accuracy of the fitness value of will also deteriorate.

  Therefore, as described in Patent Document 3 (Japanese Patent Laid-Open No. 2004-263680), the relationship between the engine control parameter and the ignition delay / combustion period based on the engine characteristic measurement data, and the ignition delay / combustion period. A misfire estimation model is created by modeling the relationship between fuel and combustion stability, and the misfire area is estimated using this misfire estimation model. Then, the necessary number of measurement points are set in the combustible area excluding the estimated misfire area. There is something to arrange.

JP 2002-206456 A JP 2005-42656 A JP 2004-263680 A

  However, in the technique of the above-mentioned Patent Document 3, since the misfire estimation model is created by almost the same process as that for creating the engine characteristic model, the man-hours for adjusting the control parameters are increased and the man-hours are reduced. The request cannot be met.

  Therefore, the problem to be solved by the present invention is to provide an engine control parameter adaptation method and an adaptation device capable of achieving both improvement in the accuracy of the engine characteristic model (improvement in accuracy of the adjustment value of the control parameter) and reduction of man-hours. .

  In order to solve the above-described problem, the invention according to claim 1 is configured to change a physical parameter (hereinafter referred to as “physical parameter”) corresponding to a change in the control parameter of the engine at a predetermined number of measurement points. Measure and create an engine characteristic model by modeling the relationship between the control parameter and the physical parameter based on the measurement results at the predetermined number of measurement points, and using the engine characteristic model, the adaptive value of the control parameter In the engine control parameter adaptation method that determines that the required performance of the engine is satisfied, an experimental design range in which a measurement point for changing the control parameter is set with a physical parameter that contributes to combustion. is there.

  In the prior art, the experimental design range of the control parameter is set by the control parameter. However, the control parameter is a command value for operating the engine, and the relationship with the actual combustion is complicated. In addition, the measured values of the physical parameters obtained from the combustion results vary greatly, and a large number of measurement steps are required to accurately define the relationship with the control parameters.

  On the other hand, in the present invention, the experimental design range of the control parameter is set with physical parameters that contribute to combustion. Since the physical parameters that contribute to combustion serve as an index that represents the combustion state, if the experimental design range is set using the physical parameters that contribute to combustion, the experimental design range can be set within the stable combustion region with a relatively small number of measurement steps. It becomes possible to set with high accuracy. In addition, since some control parameters have common physical parameters that change, when multiple control parameters that share common physical parameters are changed simultaneously, the experimental design range of the control parameters may change in a complex manner. However, if an experimental design range is set using a common physical parameter for a plurality of control parameters, a complex experimental design range can be accurately set within the stable combustion region with a relatively small number of measurement steps. It becomes possible. As a result, it is possible to achieve both improvement in the accuracy of the engine characteristic model (improvement in the accuracy of the conforming value of the control parameter) and reduction in man-hours.

  In this case, as in claim 2, the determination threshold of the physical parameter that defines the boundary of the experimental design range of the control parameter is determined so that the physical parameter does not exceed the stable combustion limit (the limit of the stable combustion region). It ’s fine. Thereby, it can prevent reliably that a measurement point is arrange | positioned in the area | region beyond the stable combustion limit, and a physical parameter can be measured with sufficient precision at all the measurement points.

  According to another aspect of the present invention, the relationship between the single control parameter and the physical parameter is obtained by changing a single control parameter, and the experimental design range when a plurality of control parameters are changed simultaneously is defined as the single unit. It may be set using the relationship between the control parameter and the physical parameter. In this way, it is not necessary to measure all combinations of control parameters, and the number of matching man-hours can be further reduced. Also, by setting the boundary of the experimental design range with physical parameters, even when multiple control parameters are changed simultaneously, the boundary line of the experimental design range tends to be monotonous, and the boundary of the experimental design range can be set even with a small number of measurement points. Predict with high accuracy.

  Further, as in claim 4, when determining the determination threshold of the physical parameter that defines the boundary of the experimental design range of a plurality of control parameters so that the physical parameter does not exceed the stable combustion limit, If the physical parameter does not exceed the stable combustion limit even at the limit of the movable range, change the other control parameter until the physical parameter exceeds the stable combustion limit with the control parameter fixed at the limit of the movable range. Thus, an experimental design range for the plurality of control parameters may be set. In this way, if the physical parameter does not exceed the stable combustion limit even if the single control parameter is changed to the limit of its movable range, the physical parameter exceeds the stable combustion limit by changing other control parameters. The measurement point can be searched, and the experimental design range can be expanded to the stable combustion limit.

  Further, as described in claim 5, when determining the adaptive value of the control parameter, the adaptive value of the control parameter may be determined in consideration of the engine characteristic model and the experimental design range of the control parameter. In this way, for example, it becomes possible to determine the conforming value of the control parameter within a range having a predetermined margin from the boundary of the experimental design range in consideration of engine differences and variations. Accuracy and robustness can be improved.

  Further, as in claim 6, while setting the experimental plan range of the control parameter under the representative operating condition based on the measurement result under the representative operating condition, predicting the change in the physical parameter due to the change in the operating condition, The experimental design range of control parameters under other operating conditions may be set based on the experimental design range of control parameters under representative operating conditions and the predicted results of changes in physical parameters due to changes in the operating conditions. In this way, it is only necessary to measure physical parameters only under the representative operating conditions, and the measurement man-hours can be reduced. In addition, because it predicts changes in physical parameters due to changes in operating conditions, it is not necessary to search for a stable combustion limit under dangerous operating conditions using actual equipment, and it is not limited by measurement accuracy. The experimental design range of control parameters can be set.

  In addition, claim 7 describes the technical idea substantially the same as the invention of the adapting method described in claim 1 as the invention of the adapting apparatus.

FIG. 1 is a diagram schematically showing a configuration example of an adaptive system in Embodiment 1 of the present invention. FIG. 2 is a diagram for explaining the types of control parameters to be matched. FIG. 3 is a flowchart showing the flow of processing of the experimental design range setting program of the first embodiment. FIG. 4 is a diagram for explaining a method for setting the experimental design range of the EGR opening according to the first embodiment using the in-cylinder EGR rate. FIG. 5 is a diagram for explaining a method of setting the experimental design range of the VCT advance value of the first embodiment using the in-cylinder EGR rate. FIG. 6 is a diagram for explaining a method of setting the experimental plan range of the injection timing retardation value of the first embodiment using the evaporated fuel amount. FIG. 7 is a diagram for explaining a method for setting the experimental design range using the in-cylinder EGR rate when the EGR opening degree and the VCT advance value are simultaneously changed in the first embodiment. FIG. 8 is a flowchart showing the flow of processing of the experimental design range setting program of the second embodiment. FIG. 9 is a diagram showing the relationship between the physical parameters (for example, in-cylinder EGR rate) and the combustion stability index (for example, torque fluctuation) in the second embodiment. FIG. 10 is a diagram for explaining a method for setting the experimental design range of the control parameter in the second embodiment so that the physical parameter is equal to or less than the determination threshold value. FIG. 11 is a flowchart showing the flow of processing of the experimental design range setting program of the third embodiment. FIG. 12 is a diagram showing measurement data of the relationship between the EGR opening degree and the in-cylinder EGR rate in the third embodiment. FIG. 13 is a diagram illustrating measurement data of the relationship between the injection timing and the spray movement distance according to the third embodiment. FIG. 14 is a diagram illustrating lines in which the evaluation functions having the in-cylinder EGR rate and the spray movement distance of Example 3 as parameters are the same value. FIG. 15 is a diagram showing an experimental design range when the EGR opening degree and the injection timing of Example 3 are changed simultaneously. FIG. 16 is a flowchart showing the flow of processing of the experimental design range setting program of the fourth embodiment. FIG. 17 is a diagram illustrating measurement data of the relationship between the VCT advance value and the in-cylinder EGR rate in Example 4. FIG. 18 is a diagram for explaining the relationship among the in-cylinder EGR rate, torque fluctuation, and stable combustion limit of the fourth embodiment. FIG. 19 is a diagram illustrating a process for calculating or measuring a physical parameter by changing the EGR opening by increments in a state where the VCT advance value of the fourth embodiment is fixed to the movable limit. FIG. 20 is a diagram showing the experimental design range set by the experimental design range setting method of Example 4. FIG. 21 is a diagram for explaining the relationship between the experimental design range and the compatible range in Example 5. FIG. 22 is a diagram for explaining a relationship between a load change and a physical parameter according to the sixth embodiment. FIG. 23 is a diagram illustrating the relationship between the rotation change and the physical parameters in the sixth embodiment. FIG. 24A shows the relationship between the physical parameters of the representative operating conditions and the evaluation function 1, FIG. 24B shows the experimental plan range of the representative operating conditions, and FIG. 24C shows the load change. The figure which shows an experiment plan range, the figure (d) is a figure which shows the experiment plan range at the time of rotation change.

  Hereinafter, six Examples 1 to 6 embodying the mode for carrying out the present invention will be described.

A first embodiment of the present invention will be described with reference to FIGS.
First, the configuration of the adaptive system will be described with reference to FIG.
A suitable engine 11 (internal combustion engine) is mounted on the bench 12, and the crankshaft of the engine 11 is connected to the dynamometer 13. During the adaptation work, various actuators (described later) mounted on the engine 11 are controlled by an electronic control unit (ECU) 14. The electronic control unit 14 is connected to the adaptation control computer 17 via the communication box 16, and the adaptation control signal is transmitted from the adaptation control computer 17 to the electronic control unit 14 via the communication box 16 during the adaptation operation. As a result, the map constant of each control parameter in the electronic control unit 14 is changed. The throttle opening degree of the engine 11 during the adaptation work is adjusted by the throttle control device 15.

  During the adaptation work, the dynamometer control panel 18 controls the dynamometer 13 and the throttle control device 15 to control the engine load, and the engine torque measured by the dynamometer 13 is transmitted to the adaptation control computer 17. The engine 11 includes a coolant temperature adjusting device 19 for adjusting the temperature of the coolant (cooling water), an oil temperature adjusting device 20 for adjusting the temperature of the engine oil, and a fuel temperature adjustment with a fuel consumption measuring function for adjusting the temperature of the fuel. While the apparatus 21 is connected and the adapting operation is performed, the coolant temperature, the engine oil temperature, and the fuel temperature are automatically adjusted to constant conditions by each of these temperature adjusting devices 21. The exhaust gas discharged from the engine 11 during the conforming work is analyzed by the exhaust gas analyzer 22, and the measurement results of emissions such as NOx, CO, and HC in the exhaust gas are transmitted to the conforming control computer 17.

  The engine 11 that can be adapted by this adaptation system may be any system such as an intake port injection engine, a direct injection engine, or a diesel engine. The control parameters to be applied include, for example, the injection timing of the fuel injection valve 23, the ignition timing of the spark plug 24, the opening of the throttle valve 25 (throttle opening) driven by a motor or the like, and the opening of the swirl control valve 26. (SCV opening), advance value of variable valve timing mechanism 27 for intake and exhaust valves (VCT advance value), opening of exhaust gas recirculation control valve 28 (EGR opening), and the like.

  If the control parameters are suitable, place a predetermined number of measurement points within the experimental design range of the control parameters determined by the method described later, change the control parameters to each measurement point, and perform the control at each measurement point. A physical quantity that changes in accordance with the change of the parameter (hereinafter referred to as “physical parameter”) is measured, and an engine characteristic model is created by modeling the relationship between the control parameter and the physical parameter based on the measurement result, and the engine The characteristic model is used to determine an appropriate value for the control parameter so that the required performance of the engine 11 is satisfied.

  In the conventional adapting method, the experimental design range (measurement point arrangement range) of the control parameter is set by the control parameter. However, the control parameter is a command value for operating the engine 11, and the actual combustion The relationship with is complicated. In addition, the measured values of physical parameters (for example, the standard deviation of the indicated mean effective pressure IMEP, the torque fluctuation, etc.) obtained by the combustion results have large variations, and a large number of measurement steps are required to accurately define the relationship with the control parameters. Is required.

  Therefore, in the first embodiment, the experimental design range of the control parameter is set with physical parameters that contribute to combustion. Since the physical parameters that contribute to combustion serve as an index that represents the combustion state, if the experimental design range is set using the physical parameters that contribute to combustion, the experimental design range can be set within the stable combustion region with a relatively small number of measurement steps. It becomes possible to set with high accuracy. In addition, since some control parameters have the same physical parameter that changes, the experimental design range of the control parameter also changes in a complex manner when multiple control parameters that have the same physical parameter change are changed simultaneously. However, if the experimental design range is set with physical parameters, a complex experimental design range can be accurately set within the stable combustion region with a relatively small number of measurement steps. As a result, it is possible to achieve both improvement in the accuracy of the engine characteristic model (improvement in the accuracy of the conforming value of the control parameter) and reduction in man-hours.

Here, when the control parameter is the EGR opening degree, the physical parameters changed thereby are the in-cylinder EGR rate, the intake pipe pressure, and the like.
When the control parameter is a VCT advance value, the physical parameters that change thereby are the in-cylinder EGR rate, the in-cylinder flow velocity, the intake air temperature, the pumping loss, the intake pipe pressure, the actual compression ratio, and the like.
When the control parameter is the injection timing, the physical parameters that change thereby are the spray movement distance, the atomization time, the evaporated fuel amount (ratio), the in-cylinder flow velocity during injection, and the like.

  In the first embodiment, the relationship between the control parameter and the physical parameter is obtained by simulation or actual equipment, and the experimental design range is set by the physical parameter. For example, the in-cylinder EGR rate is a predetermined percentage or less, or the in-cylinder flow velocity is a predetermined m / s or more.

  Alternatively, an AND (logical product) of a plurality of physical parameters may be taken. For example, a range in which the in-cylinder EGR rate is equal to or less than a predetermined percentage and the in-cylinder flow velocity is equal to or greater than a predetermined m / s may be set as the experimental design range of the VCT advance value.

  Further, since the EGR and the variable valve timing mechanism 27 (VCT) have a role of returning the exhaust gas into the cylinder and changing the internal EGR rate, these two control parameters are correlated to each other, and the external EGR rate by the EGR is The experimental design range to be set also changes depending on the in-cylinder EGR rate that is the sum of the internal EGR rate by VCT. Therefore, when the EGR and VCT are changed by simulation, the EGR amount introduced into the cylinder is calculated, and the range where the same in-cylinder EGR rate is equal to or less than the same is set as the experimental design range.

  In addition, a predetermined number of measurement points are arranged in a wide range by the experimental design method, and measurement points whose physical parameters exceed the determination threshold are excluded before measurement, and the excluded measurement points are less than the determination threshold. You may make it rearrange within the experiment plan range.

If the physical parameter measured at any of the measurement points placed within the set experimental design range exceeds the judgment threshold, correct the experimental design range and correct the measurement point where the physical parameter exceeds the judgment threshold. You may make it rearrange within the experimental design range later.
When the physical parameters are arranged by the experimental design method, the physical parameters may be arranged in consideration of the characteristics of the physical parameters.

The setting of the experiment plan range of the first embodiment is performed according to the following procedure in accordance with the experiment plan range setting program (experiment plan range setting means) of FIG.
First, in step 101, a physical parameter for a control parameter to be matched is selected.

  For example, if the control parameter to be matched is the EGR opening, either the in-cylinder EGR rate or the intake pipe pressure is selected as the physical parameter for that (in the example of FIG. 4, the in-cylinder EGR rate is selected. )

  If the control parameter to be matched is a VCT advance value, the physical parameter is selected from the in-cylinder EGR rate, the in-cylinder flow velocity, the intake air temperature, the pumping loss, the intake pipe pressure, and the actual compression ratio (see FIG. In the example of 5, the in-cylinder EGR rate is selected).

  If the control parameter to be matched is the injection timing, a physical parameter corresponding to it is selected from the spray movement distance, the atomization time, the evaporated fuel amount (ratio), and the in-cylinder flow velocity during injection (in the example of FIG. 6). Evaporative fuel amount is selected).

  As shown in FIG. 7, when the EGR opening degree and the VCT advance value are changed simultaneously, either the in-cylinder EGR rate or the intake pipe pressure may be selected as a physical parameter common to both (see FIG. 7). In the example, the in-cylinder EGR rate is selected).

  In the next step 102, the relationship between the control parameter and the physical parameter (solid line in FIGS. 4 to 7) is calculated from the measurement data obtained by simulation or actual machine. Thereafter, the process proceeds to step 103, the value of the control parameter that causes the determination threshold of the physical parameter that defines the boundary of the experimental design range of the control parameter is calculated, and the experimental design range of the control parameter is determined in the next step 104. .

  A predetermined number of measurement points are arranged within the experimental design range of the control parameter determined as described above, the control parameter is changed to each measurement point, the physical parameter is measured at each measurement point, and the measurement result Based on the above, a relationship between the control parameter and the physical parameter is modeled to create an engine characteristic model, and an adaptive value of the control parameter is determined using the engine characteristic model so that the required performance of the engine 11 is satisfied.

  According to the first embodiment described above, the experimental design range of the control parameter is set by the physical parameter that serves as an index representing the combustion state. Therefore, the experimental design range can be set within the stable combustion region with a relatively small number of measurement steps. Can be set with high accuracy. In addition, since some control parameters have common physical parameters that change, when multiple control parameters that share common physical parameters are changed simultaneously, the experimental design range of the control parameters may change in a complex manner. However, if an experimental design range is set using a common physical parameter for a plurality of control parameters, a complex experimental design range can be accurately set within the stable combustion region with a relatively small number of measurement steps. It becomes possible. As a result, it is possible to achieve both improvement in the accuracy of the engine characteristic model (improvement in the accuracy of the conforming value of the control parameter) and reduction in man-hours.

Next, Embodiment 2 of the present invention will be described with reference to FIGS.
In the second embodiment, the determination threshold of the physical parameter that defines the boundary of the experimental design range of the control parameter is determined so that the physical parameter does not exceed the stable combustion limit (the limit of the stable combustion region). Here, the stable combustion limit is determined by a combustion stability index. As the combustion stability index, for example, COV (standard deviation of the indicated mean effective pressure IMEP), torque fluctuation, spark plug vicinity equivalence ratio, etc. may be used. By using these combustion stability indexes, the stable combustion limit can be accurately determined.

  In the combustion deterioration area, misfire, combustion instability, or engine damage due to abnormal combustion may occur, so if the measurement point exceeds the stable combustion limit and is placed in the combustion deterioration area, the measurement point is measured. Accuracy deteriorates or measurement becomes impossible.

  Since the judgment threshold of the physical parameter that determines the stable combustion limit may vary depending on the engine model and product specifications, the relationship between the physical parameter and the combustion stability index is obtained for each applicable system, and the physical parameter A determination threshold value may be obtained.

  What is necessary is just to obtain | require the relationship between the control parameter of an applicable object system, and a combustion stability parameter | index by a real machine or simulation. When obtaining this relationship with an actual machine, as shown in FIG. 9, the physical parameter (for example, in-cylinder EGR rate) and the combustion stability index (for example, torque fluctuation) when the control parameter is changed are measured, and the two measured The relationship between the data is obtained, and the value of the physical parameter whose combustion stability index exceeds the stable combustion limit may be determined as the determination threshold value.

  After the determination threshold value is determined, as shown in FIG. 10, the range in which the physical parameter is equal to or less than the determination threshold value in FIG. 9 in the relationship between the control parameter (for example, EGR opening degree) and the physical parameter (for example, in-cylinder EGR rate) is tested. It may be the planned scope. Thereby, the experimental design range can be set within the stable combustion region.

  The setting of the experimental design range of the second embodiment is performed according to the following procedure according to the experimental design range setting program of FIG. First, in step 201, a physical parameter for a control parameter to be matched is selected in the same manner as in the first embodiment, and in the next step 202, a combustion stability index for the selected physical parameter is selected as COV, torque fluctuation, Select from spark plug vicinity equivalence ratio, etc.

  In the next step 203, physical parameters and combustion stability indices for the control parameters are calculated or measured by simulation or actual equipment. Thereafter, in step 204, the value of the physical parameter at which the combustion stability index exceeds the stable combustion limit is determined as a determination threshold from the relationship between the physical parameter and the combustion stability index.

  Thereafter, in step 205, from the relationship between the control parameter and the physical parameter, the control parameter value at which the physical parameter becomes the determination threshold is calculated as the boundary value of the experimental design range. In the next step 206, the experimental design of the control parameter is calculated. Determine the range.

  According to the second embodiment described above, the determination threshold of the physical parameter that determines the boundary of the experimental design range of the control parameter is determined so that the physical parameter does not exceed the stable combustion limit (the limit of the stable combustion region). Therefore, it is possible to reliably prevent the measurement points from being arranged in the region exceeding the stable combustion limit, and it is possible to accurately measure physical parameters at all measurement points.

Next, Embodiment 3 of the present invention will be described with reference to FIGS.
In the third embodiment, a single control parameter is changed, the relationship between the single control parameter and the physical parameter is obtained by an actual machine or a simulation, and an experiment plan range in the case where a plurality of control parameters are changed at the same time is determined. It is set using the relationship between one control parameter and a physical parameter. In this way, it is not necessary to measure all combinations of control parameters by an actual machine or simulation, and the number of man-hours can be further reduced.

  Also, by setting the boundary of the experimental design range with physical parameters, even when multiple control parameters are changed simultaneously, the boundary line of the experimental design range tends to be monotonous, and the boundary of the experimental design range can be set even with a small number of measurement points. Predict with high accuracy.

  For example, when simultaneously changing the EGR opening degree and the injection timing, first, as shown in FIG. 12, the relationship between the EGR opening degree and the in-cylinder EGR rate is obtained by an actual machine or a simulation, and as shown in FIG. The relationship between the injection timing and the spray travel distance (the distance traveled until the fuel injected by the fuel injection valve 23 burns) is measured or calculated by an actual machine or simulation.

  When there is a correlation between two measured or calculated physical parameters, one evaluation function is created by weighting, addition / subtraction multiplication, etc., and when there is no correlation, an independent evaluation function is created.

In the examples of FIGS. 12 and 13, the two physical parameters measured or calculated are the in-cylinder EGR rate and the spray movement distance, and have a correlation, so one evaluation function is created with the two physical parameters as variables. To do.
Evaluation function = a × in-cylinder EGR rate + b × spray movement distance In the above formula, a and b are coefficients. This evaluation function means that the larger the value, the lower the combustion stability.

  When the evaluation function is defined by a linear expression having two physical parameters (in-cylinder EGR rate and spray movement distance) as variables as in the above equation, the evaluation function is set to the same value as shown in FIG. The line becomes a straight line. Since the value of the evaluation function is a combustion stability index, a range where the value of the evaluation function is equal to or less than a predetermined threshold is determined as a stable combustion region, and a physical parameter whose value of the evaluation function is a predetermined threshold (stable combustion limit) Using (in-cylinder EGR rate and spray movement distance), control parameters (EGR opening and injection timing) at which the value of the evaluation function becomes a predetermined threshold are calculated from the relationship between FIG. 12 and FIG. As shown, an experimental design range of control parameters (EGR opening and injection timing) at which the value of the evaluation function is equal to or less than a predetermined threshold is set. Thereby, the experimental design range can be set within the stable combustion region.

  The setting of the experimental design range of the third embodiment is performed according to the following procedure in accordance with the experimental design range setting program of FIG. First, in step 301, a physical parameter corresponding to a control parameter to be matched is selected by the same method as in the first embodiment, and in the next step 302, the relationship between a single control parameter and a physical parameter is simulated or actual machine. The process of calculating or measuring is repeated for the number of suitable control parameters.

  Thereafter, in step 303, the value of the evaluation function is calculated using the correlated physical parameters. In the next step 304, the control parameter value at which the value of the evaluation function becomes a predetermined threshold (stable combustion limit) is calculated as the boundary value of the experimental design range. In the next step 305, the experimental design range of the control parameter is determined. To do.

Next, Embodiment 4 of the present invention will be described with reference to FIGS.
In the fourth embodiment, when the determination threshold of the physical parameter that defines the boundary of the experimental design range of a plurality of control parameters is determined so that the physical parameter does not exceed the stable combustion limit, the movable range of any control parameter is determined. If the physical parameter does not exceed the stable combustion limit even at the limit (movable limit), change the other control parameters until the physical parameter exceeds the stable combustion limit with the control parameter fixed at the movable limit. An experimental design range for the plurality of control parameters is set. In this way, if the physical parameter does not exceed the stable combustion limit even if the single control parameter is changed to its movable limit, the other control parameters are changed to change the measurement point where the physical parameter exceeds the stable combustion limit. And the experimental design range can be expanded to the stable combustion limit. In addition, it is possible to accurately set an experimental design range in consideration of control parameters that do not significantly affect the combustion stability even if the movable range is changed independently.

  For example, a method for setting the experimental design range of the VCT advance value and the EGR opening will be described with reference to FIGS. As shown in FIGS. 17 and 18, even if the VCT advance value is changed to the movable limit, the in-cylinder EGR rate, which is a physical parameter, does not exceed the determination threshold corresponding to the stable combustion limit.

  Therefore, as shown in FIG. 19, with the VCT advance value fixed at the movable limit, the EGR opening, which is another control parameter, is changed by a predetermined increment (this process is hereinafter referred to as “increment”), The process of calculating or measuring the in-cylinder EGR rate, which is a physical parameter, by simulation or actual equipment is repeated until the in-cylinder EGR rate exceeds a determination threshold corresponding to the stable combustion limit. Note that the physical parameter obtained by changing the VCT advance value may be different from the physical parameter obtained by changing the in-cylinder EGR rate.

  The method of calculating the increment amount of the EGR opening is obtained by converting the value obtained by dividing the value of the physical parameter corresponding to the stable combustion limit (determination threshold) by an integer into the change amount of the EGR opening as the increment amount. Just do it.

  The setting of the experimental design range of the fourth embodiment is performed according to the following procedure in accordance with the experimental design range setting program of FIG. First, in step 401, a physical parameter for the control parameter A to be matched is selected in the same manner as in the first embodiment, and in the next step 402, a combustion stability index for the selected physical parameter is selected as COV, torque fluctuation. Select from the equivalent ratio in the vicinity of the spark plug.

  In the next step 403, a physical parameter and a combustion stability index for the control parameter A are calculated or measured by simulation or actual equipment. Thereafter, in step 404, the value of the physical parameter at which the combustion stability index reaches the stable combustion limit is determined as a determination threshold value from the relationship between the physical parameter and the combustion stability index.

  Thereafter, in step 405, it is determined whether or not the physical parameter exceeds the determination threshold value. If the physical parameter does not exceed the determination threshold value, the process proceeds to step 409, and the control parameter B having a strong correlation with the control parameter A is selected. . In the next step 410, a physical parameter and a combustion stability index for the control parameter B are calculated or measured by simulation or actual equipment. Thereafter, in step 411, the value of the physical parameter at which the combustion stability index reaches the stable combustion limit is determined as a determination threshold value from the relationship between the physical parameter and the combustion stability index.

  Thereafter, in step 412, the value obtained by converting the value of the physical parameter corresponding to the stable combustion limit (determination threshold) by the integer is converted into the change amount of the control parameter B, and the increment amount is set. In the next step 413, in a state where the control parameter A is fixed at the movable limit, the control parameter B is changed by the increment amount to calculate or measure the physical parameter.

  Thereafter, in step 414, it is determined whether or not the physical parameter exceeds the determination threshold value. If the physical parameter does not exceed the determination threshold value, the process returns to step 413. Thus, the process of calculating or measuring the physical parameter by changing the control parameter B by the increment amount is repeated until the physical parameter exceeds the determination threshold.

  Thereafter, when it is determined in step 414 or 405 that the physical parameter has exceeded the determination threshold, the process proceeds to step 406, and the value of the control parameter at which the physical parameter becomes the determination threshold is determined from the relationship between the control parameter and the physical parameter. The calculation is made as a boundary value of the experimental design range, and in the next step 407, the experimental design range of the control parameter is determined (see FIG. 20).

Next, Embodiment 5 of the present invention will be described with reference to FIG.
In the fifth embodiment, when determining the adaptive value of the control parameter, the adaptive value of the control parameter is determined in consideration of the engine characteristic model and the experimental design range of the control parameter. In this way, for example, it becomes possible to determine the conforming value of the control parameter within the conforming range having a predetermined margin from the boundary of the experimental design range in consideration of product machine differences and variations. Accuracy and robustness can be improved.

Next, Embodiment 5 of the present invention will be described with reference to FIGS.
In the sixth embodiment, the experimental plan range of the control parameter under the representative operation condition is set based on the measurement result under the representative operation condition, the change in the physical parameter due to the change in the operation condition is predicted, and the representative operation condition Based on the experimental design range of the control parameter in the above and the prediction result of the change of the physical parameter due to the change of the operation condition, the experimental design range of the control parameter in other operation conditions is set. In this way, it is only necessary to measure physical parameters only under the representative operating conditions, and the measurement man-hours can be reduced. In addition, because it predicts changes in physical parameters due to changes in operating conditions, it is not necessary to search for a stable combustion limit under dangerous operating conditions using actual equipment, and it is not limited by measurement accuracy. The experimental design range of control parameters can be set.

  Specifically, first, the relationship between the control parameter and the physical parameter is calculated or measured by simulation or actual equipment under the representative operation condition, and for example, the control parameter under the representative operation condition is calculated in the same manner as in the third embodiment. The experimental design range [shaded area in FIG. 24B] is set. In the example of FIG. 24, the experimental design range of the control parameter is an area surrounded by the evaluation function 1 and the evaluation function 2, but the evaluation function 2 allows the entire operation area under the representative operation conditions. Therefore, the experimental design range of the control parameter under the representative operation condition is an area surrounded by the evaluation function 1.

  Next, as shown in FIG. 22, the relationship between the control parameter and the physical parameter when the load changes is predicted, and the experimental design range of the control parameter at the time of the load change [shaded area in FIG. Predict. Since the evaluation function 2 allows the entire operation region when the load changes, the experimental design range of the control parameter when the load changes is the region surrounded by the evaluation function 1.

  Further, as shown in FIG. 23, the relationship between the control parameter and the physical parameter when the engine rotation speed is changed is predicted, and the experimental plan range of the control parameter at the time of the rotation change shown in FIG. (D) hatched portion] is predicted. The experimental design range of the control parameter at the time of rotation change is an area surrounded by the evaluation function 1 and the evaluation function 2.

  Thereafter, the experimental design range of the control parameter under other operating conditions is set based on the experimental design range (evaluation function 1) of the control parameter under the representative operating condition and the predicted result of the change of the physical parameter due to the change of the operating condition. .

  The present invention is not limited to the first to sixth embodiments described above, and the scope of the invention does not depart from the gist, such as the control parameters to be matched and the physical parameters that change according to the changes in the control parameters. It can be implemented with various changes.

  DESCRIPTION OF SYMBOLS 11 ... Engine, 14 ... Electronic control unit (ECU), 17 ... Adaptation control computer (experiment plan range setting means)

Claims (7)

By changing the control parameter of the engine to be measured, a physical quantity that changes in accordance with the change of the control parameter (hereinafter referred to as “physical parameter”) is measured at a predetermined number of measurement points, and the measurement is performed at the predetermined number of measurement points. Based on the result, a relationship between the control parameter and the physical parameter is modeled to create an engine characteristic model, and the engine characteristic model is used to determine an appropriate value of the control parameter so that the required performance of the engine is satisfied. In the engine control parameter adaptation method,
An engine control parameter adaptation method, characterized in that an experimental design range in which a measurement point for changing the control parameter is arranged is set as a physical parameter that contributes to combustion. The engine control parameter adaptation method according to claim 1,
A method for adapting engine control parameters, wherein a determination threshold value of a physical parameter that defines a boundary of an experimental design range of the control parameter is determined so that the physical parameter does not exceed a stable combustion limit. The engine control parameter adaptation method according to claim 1,
The relationship between the single control parameter and the physical parameter is obtained by changing a single control parameter to obtain the relationship between the single control parameter and the physical parameter. A method for adapting engine control parameters, which is set using The method for adapting engine control parameters according to claim 2,
When determining the determination threshold of a physical parameter that defines the boundary of the experimental design range of a plurality of control parameters so that the physical parameter does not exceed the stable combustion limit, the physical parameter is not limited to the limit of the movable range of any of the control parameters. If the stable combustion limit is not exceeded, the control parameter is fixed at the limit of the movable range, and other control parameters are changed until the physical parameter exceeds the stable combustion limit, and the experimental plan of the plurality of control parameters is set. A method for adapting engine control parameters, characterized by setting a range. The engine control parameter adaptation method according to claim 1,
A method for adapting an engine control parameter, wherein the adaptive value of the control parameter is determined in consideration of the engine characteristic model and an experimental design range of the control parameter when determining the adaptive value of the control parameter. The engine control parameter adaptation method according to claim 1,
Based on the measurement results under the representative operating conditions, set the experimental plan range of the control parameters under the representative operating conditions, predict the change in the physical parameters due to the change in the operating conditions, and experiment with the control parameter under the representative operating conditions. An engine control parameter adaptation method, characterized in that an experimental plan range of control parameters under other operating conditions is set based on a predicted range and a predicted result of changes in physical parameters due to changes in the operating conditions. By changing the control parameter of the engine to be measured, a physical quantity that changes in accordance with the change of the control parameter (hereinafter referred to as “physical parameter”) is measured at a predetermined number of measurement points, and the measurement is performed at the predetermined number of measurement points. Based on the result, a relationship between the control parameter and the physical parameter is modeled to create an engine characteristic model, and the engine characteristic model is used to determine an appropriate value of the control parameter so that the required performance of the engine is satisfied. In the engine control parameter adapting device to
An engine control parameter adaptation apparatus, comprising: an experimental design range setting means for setting an experimental design range in which measurement points for changing the control parameters are arranged with physical parameters that contribute to combustion.

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