JP5053243B2 - Method and apparatus for searching for optimum value - Google Patents

Description

  The present invention relates to a method and apparatus for searching for an optimum value.

  2. Description of the Related Art Conventionally, ECU (Electronic Control Unit) control that comprehensively performs electrical control in engine operation or the like is known. The ECU control controls control items such as engine injection amount and injection time, idling speed, and ignition timing based on information from each sensor. Such ECU control efficiently controls the engine by optimizing the value of the setting item provided for each control item.

For example, Patent Document 1 is known as a method for realizing engine efficiency. Patent Document 1 describes a fuel injection control device for a feedforward type diesel engine for the purpose of realizing optimization of the fuel injection rate easily at high speed. That is, the invention described in Patent Document 1 uses a neural network while optimizing the opening and closing timing of the relief valve so that the actual measurement value approaches the fuel injection pattern by repeatedly trying to open and close the relief valve within the injection period. An arithmetic unit for estimating an unmeasured value by learning is provided. The learning function is designed based on learning data obtained by repeating the opening / closing of the relief valve or the valve opening timing within the injection period so that the actual measurement value of the pressure sensor approaches the target fuel injection pattern. It is characterized in that the injection rate is optimized while correcting a predetermined valve operation timing at the time of testing or testing.
JP 2001-304027 A

  However, the method as described in Patent Document 1 is effective when it is performed in a very short period of time, such as fuel injection, but is suitable for optimizing a device having a delay element (for example, temperature, pressure, etc.). Because it is difficult to learn about the delay element, it is not effective. For those having such a delay element, it is necessary to perform step-by-step measurement in which the result of ECU control is monitored for a while after the value of the setting item is changed. In the measurement for each stage, it is necessary to monitor the temperature and the like for each stage, and therefore it takes an enormous amount of time to reach the limit value of the control item. For example, in order to monitor up to the limit value with 5% accuracy, 20 steps are required. If the delay time for each step is 30 seconds, 600 seconds (30 seconds × 20 steps) are required. Then, in order to obtain the optimum value for the setting item of the control item having a delay element, it is necessary to perform measurement at each stage where the setting items are combined, and further time is required.

  Therefore, there is a need for a method for quickly obtaining an optimum value for a setting item of a control item having a delay element among ECU control items.

  An object of the present invention is to provide a method and an apparatus for quickly obtaining an optimum value for a setting item of a control item having a delay element among ECU control items.

  The present invention provides the following solutions.

(1) In the ECU control of the engine, the computer sweeps the optimum value of the setting item so that the value of the measurement item becomes the value closest to the preset target value while sweeping from the predetermined initial value. An initial measurement step of measuring a measurement item when the ECU is controlled at an initial value of the setting item, and subsequently sweeping the setting item, A sweep measurement step for performing measurement, a step for obtaining a quadratic curve that fits a change in a series of measurement values in the initial measurement step and the sweep measurement step, and a maximum value of the slope of the obtained quadratic curve as a slope. The intersection of the straight line with the measured value of the initial measurement step as an intercept and the predetermined limit value of the measurement item of the ECU control is obtained, and the obtained intersection Predicting the threshold value as a limit value, and measuring the predicted limit value until a predetermined time and monitoring that the predetermined limit value is not exceeded, thereby setting the predicted limit value as a limit value. Repetitively repeating the step of setting the limit value from the initial measurement step for different directions of the sweep, a step of obtaining a range by a plurality of the limit values obtained by repeating, and the setting item further within the obtained range Measuring the measurement item while changing the value, and obtaining an optimum value of the setting item .

According to the configuration of (1), according to the method of the present invention, in the ECU control of the engine, the setting item for causing the value of the measurement item to be a value closest to the preset target value is set. A method of searching for an optimum value from a predetermined initial value to a limit value while measuring the measurement item when ECU control is performed at the initial value of the setting item, and subsequently sweeping the setting item. While measuring the measurement items, find a quadratic curve that fits the change in the series of measured values, the straight line with the maximum value of the slope of the obtained quadratic curve as the slope and the measured value in the initial measurement step as an intercept, and the ECU Calculate the intersection of the control measurement item with the specified limit value, predict the calculated intersection point as the limit value, measure the predicted limit value until the specified time, and monitor that the specified limit value is not exceeded To do Accordingly, the predicted limit value is set as the limit value, the range from the initial measurement step to the limit value is repeated for different directions of the sweep, the range is determined by a plurality of limit values obtained by repeating, and further setting items within the determined range Measure the measurement item while changing the value to find the optimum value of the setting item.

Therefore, according to the method of the present invention, when the computer searches for the optimum value of the setting item for ECU control of the engine, the computer predicts the value for the limit value while sweeping from the predetermined initial value , The measured value is monitored for a predetermined time to obtain a limit value, and measurement is performed within the range of the limit value to search for the optimum value of the setting item . Therefore, the method according to the present invention can quickly obtain the optimum value for the setting item of the control item having a delay element among the ECU control items.

(2) the method, the combination of setting items for ECU control, combining obtains the limit values for setting items was, determined the method described in finding (1) the optimum value within the range of the limit value .

According to the configuration of (2) , in addition to (1 ), the method according to the present invention combines setting items for ECU control, obtains a limit value for the combined setting items, and falls within the range of the obtained limit value. To find the optimum value.

Therefore, the method according to the present invention, the computer, the optimum value of the setting item for ECU controlling the engine, the limit value a limit value predicted by combining setting item, within the determined limit value to probe search. Therefore, the method according to the present invention can quickly obtain the optimum value for the setting item of the control item having a delay element among the ECU control items.

(3) In the ECU control of the engine, the limit is set while the optimum value of the setting item is swept from a predetermined initial value so that the value of the measurement item becomes the value closest to the preset target value. An optimum value search device for searching up to a value, wherein initial measurement means for measuring a measurement item when the ECU is controlled at an initial value of the setting item, and continuously sweeping the setting item Sweep measurement means for measuring measurement items, quadratic curve calculation means for obtaining a quadratic curve that fits a series of measurement value changes in the initial measurement means and the sweep measurement means, and the slope of the obtained quadratic curve The intersection of the straight line having the maximum value of the slope and the intercept of the measurement value of the initial measurement means and the predetermined limit value of the measurement item of the ECU control is obtained, and the obtained intersection is Prediction means for predicting a serial limit value, the limit value the predicted, was measured until a predetermined time, the limit value and the limit value the predicted by monitoring that does not exceed the predetermined limit value limits Point determining means and range determining means for obtaining a range based on a plurality of limit values obtained by repeating and repeatedly setting the limit value by the limit point searching means from the measurement by the initial measuring means for different directions of the sweep And an optimum value search means for measuring the measurement item while further changing the setting item within the obtained range and obtaining an optimum value of the setting item .

Therefore, according to the optimum value search apparatus according to the present invention, the computer, the engine when searching the optimum value of the setting item for ECU control, while sweeping the value of the limit value from a predetermined initial value prediction Then , the predicted value is monitored for a predetermined time to be a limit value, and measurement is performed within the range of the limit value to search for the optimum value of the setting item . Therefore, the optimum value search apparatus according to the present invention can quickly obtain the optimum value for the setting item of the control item having a delay element among the ECU control items.

  ADVANTAGE OF THE INVENTION According to this invention, the method and apparatus which obtain | require an optimal value rapidly about the setting item of the control item with a delay element in ECU control items can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing features of the present invention. An optimum value search apparatus 10 according to an embodiment of the present invention includes an initial measurement unit 11 that performs an initial measurement step, a sweep measurement unit 12 that performs a sweep measurement step, and a method according to the present invention. A quadratic curve calculation unit 13 that executes a quadratic curve calculation step and a prediction unit 14 that executes a prediction step are provided. Then, the optimum value search device 10 searches for the optimum value of the setting item for ECU control from the predetermined initial value to the limit value while sweeping. For example, torque that is one of setting items for ECU control of the engine and exhaust temperature that is a measurement item when ECU control is performed are shown as examples. When the torque, which is a setting item, is changed, the exhaust temperature, which is a measurement item, changes after a change in torque.

  The initial measurement unit 11 measures the measurement item when ECU control is performed at the initial value of the setting item. For example, the initial measurement unit 11 measures the initial value of the exhaust temperature at the initial value of the torque. For the initial value, for example, the center value is set as the initial value among possible values that the torque can take based on the experimental design. Under this initial value, the exhaust temperature does not exceed a limit value that must not exceed even if ECU control is performed.

  The sweep measurement unit 12 measures the measurement item while continuously sweeping the setting item from the initial value. For example, the sweep measurement unit 12 measures the exhaust temperature while continuously changing the torque.

  The quadratic curve calculation unit 13 obtains a quadratic curve that fits a change in a series of measurement values measured by the initial measurement unit 11 and the sweep measurement unit 12. For example, when the torque is continuously changed, the quadratic curve calculation unit 13 obtains a quadratic curve that approximates the measured value based on the measured value of the changing exhaust temperature.

  The prediction unit 14 obtains and obtains an intersection of a straight line having the maximum slope of the obtained quadratic curve as an inclination and an intercept of the measurement value of the initial measurement step, and a predetermined limit value of the measurement item of the ECU control. Predict the intersection point as the limit value. For example, the prediction unit 14 obtains a quadratic curve that approximates the measured value of the exhaust temperature, and based on the measured value of the current exhaust temperature on the obtained quadratic curve and the measured value of the immediately previous exhaust temperature, a straight line Is obtained, and a straight line having an intercept of the obtained inclination and the initial value of the exhaust temperature is obtained. Then, an intersection point between the obtained straight line and the exhaust temperature limit value is calculated, and a torque value corresponding to the calculated intersection point is obtained. In this way, the torque value calculated when the gradient is maximum in the straight line obtained each time measurement is performed while sweeping is predicted as the limit value. That is, the prediction unit 14 stores the torque value calculated each time measurement is performed while sweeping, and the torque value being changed is one of the stored torque values (for example, in the direction of increasing torque). If it is changed, if it exceeds the minimum value calculated when the slope of the obtained straight line is maximum, it is determined that the predicted limit value has been exceeded.

  The optimum value search device 10 searches for an optimum value of a setting item for ECU control from a predetermined initial value to a predicted limit value while sweeping.

  FIG. 2 is a functional block diagram showing functions of the optimum value searching apparatus 10 according to one embodiment of the present invention. In addition to the features of FIG. 1, the optimum value search device 10 according to an embodiment of the present invention includes a limit point search unit 15 that executes a search step, a range determination unit 16 that executes a step for determining a range, and an optimal value And an optimum value search unit 17 for executing the step of obtaining.

  The limit point search unit 15 measures the predicted limit value until a predetermined time, and sets the predicted limit value as a limit value by monitoring that the predetermined limit value is not exceeded. For example, the limit point search unit 15 stops the change of the torque when the value of the torque being changed exceeds the predicted limit value, and then stops exhausting the torque for a predetermined time while stopping the change of the torque. The temperature is monitored to monitor that the exhaust temperature limit value is not exceeded, and this torque value is set as the limit point value, that is, the searched limit value.

  The range determination unit 16 obtains a range based on a plurality of limit values obtained by repeating and repeating the steps from the initial measurement step to the limit value in different directions of the sweep. For example, in the case where there are two setting items A and B, the range determination unit 16 combines the case where the setting item A is increased and decreased and the case where the setting item B is increased and decreased (for example, , A and B are increased in different directions) from initial measurement to setting the limit value, a plurality of limit values are obtained, and a range for searching for the optimum value is obtained.

  The optimum value search unit 17 measures the measurement item while further changing the setting item within the obtained range, and obtains the optimum value of the setting item. For example, the optimum value search unit 17 measures the measurement item while gradually changing the setting item within the range of the obtained limit value in the increasing direction and the limit value in the decreasing direction, and the optimum value of the setting item for the measurement item Ask for.

  FIG. 3 is a diagram illustrating an example of a hardware configuration of the optimum value search apparatus 10 according to an embodiment of the present invention. The optimum value search apparatus 10 includes a CPU (Central Processing Unit) 1010, a bus line 1005, a communication I / F 1040, a main memory 1050, a BIOS (Basic Input Output System) 1060, an I / O controller 1070, a keyboard and mouse 1100, and a display. A device 1022 is provided.

  Storage means such as a hard disk 1074 and a semiconductor memory 1078 can be connected to the I / O controller 1070.

  The BIOS 1060 stores a boot program executed by the CPU 1010 when the optimum value search apparatus 10 is started, a program depending on the hardware of the optimum value search apparatus 10, and the like.

  The hard disk 1074 stores a program for the optimum value search apparatus 10 to execute the function of the present invention, and can further constitute various databases such as an optimum value search table and a limit value storage table.

  The program provided to the optimum value search apparatus 10 is provided by being stored in a recording medium such as the hard disk 1074 or a memory card. This program may be read from the recording medium via the I / O controller 1070 or downloaded via the communication I / F 1040 to be installed and executed in the optimum value search apparatus 10.

  The aforementioned program may be provided to the optimum value search apparatus 10 via a communication line using a storage device such as a hard disk or an optical disk library provided in a server system connected to a dedicated communication line as a recording medium.

  Here, the display device 1022 displays a screen of a calculation processing result by the optimum value search device 10, and includes a display device such as a cathode ray tube display device (CRT) or a liquid crystal display device (LCD).

  The communication I / F 1040 is a network adapter for enabling the optimum value search apparatus 10 to be connected to a terminal (for example, an ECU control unit) via a dedicated network. The communication I / F 1040 may include a modem, a cable modem, and an Ethernet (registered trademark) adapter.

  FIG. 4 is a diagram showing an optimum value search table of the optimum value search apparatus 10 according to an embodiment of the present invention. The optimum value search table includes an ECU control item, a setting item, a measurement item, an initial value, a limit value, a limit value measurement time, a target value, a stepped measurement time, a sweep measurement time, The change direction is memorized. The ECU control items and setting items are ECU control items and setting items for searching for an optimum value, such as exhaust temperature control and torque. The measurement item is an item to be measured for the control item, and is, for example, the exhaust temperature. The initial value is an initial value of the setting item. The limit value is a limit value that the measurement item must not exceed, such as a limit value of the exhaust temperature. The limit value measurement time is a time during which the setting item is measured while maintaining the limit value. For example, the limit value measurement time is a time during which it is monitored that the measurement value does not exceed the monitoring value at the limit value predicted by the setting item. The target value is a target measurement value, and in the case of this measurement value, the value of the setting item can be determined as the optimum value. The stepwise measurement time is a measurement time for each step when measuring stepwise. The measurement time for sweep is the measurement time when performing sweep measurement. The change direction is the number of types of directions in which the setting item is changed. For example, four directions (setting item A increase and setting item B increase, setting item A increase and setting item B decrease, setting item A decrease and setting item B increase) , Setting item A decrease and setting item B decrease).

  FIG. 5 is a diagram showing a limit value storage table of the optimum value search apparatus 10 according to an embodiment of the present invention. The limit value storage table stores directions, limit values, predictions, and search results. The direction is a direction in which the setting item changes, for example, an increasing direction or a decreasing direction. The limit value is a limit value calculated from the obtained quadratic curve and straight line. The prediction is set when prediction is performed as a limit value. The search result is set when the limit value is not exceeded.

  FIG. 6 is a flowchart showing the processing contents of the optimum value search apparatus 10 according to an embodiment of the present invention. Note that this processing is started by receiving a program start command, for example, and is ended by a program end command or an end condition.

  In step S101, the CPU 1010 performs limit range processing. By this limit range processing, a range for searching for the optimum value of the setting item is acquired. Thereafter, the CPU 1010 advances the processing to step S102.

  In step S102, the CPU 1010 performs measurement step by step within the range. More specifically, the CPU 1010 changes the value of the setting item within the acquired range, and performs measurement based on the stepwise measurement time of the optimum value search table under the changed setting item value. Thereafter, the CPU 1010 advances the processing to step S103.

  In step S103, the CPU 1010 determines whether or not the value is an optimum value. That is, the CPU 1010 determines whether or not the measured value is within the target value range of the optimum value search table. If this determination is YES, the process moves to a step S104, and if NO, the process moves to a step S102.

  In step S104, the CPU 1010 stores the optimum value. That is, the value of the setting item in this case is stored as an optimum value. Thereafter, the CPU 1010 ends the process.

  FIG. 7 is a flowchart showing the contents of limit range processing of the optimum value search apparatus 10 according to an embodiment of the present invention.

  In step S201, the CPU 1010 measures the center point. That is, the measurement is performed using the initial value of the optimum value search table set in advance based on the experimental design method. Thereafter, the CPU 1010 shifts the processing to step S202.

  In step S202, the CPU 1010 performs a sweep measurement. More specifically, the CPU 1010 changes the value of the setting item based on the sweep measurement time in the optimum value search table, and measures and stores the measurement item when changed. Thereafter, the CPU 1010 advances the processing to step S203.

  In step S203, the CPU 1010 performs limit value prediction processing. In the limit value prediction process, the limit value is calculated for each change of the setting item and stored in the limit value storage table. Thereafter, the CPU 1010 advances the processing to step S204.

  In step S204, the CPU 1010 determines whether or not the value of the setting item has exceeded the predicted limit value. More specifically, the CPU 1010 compares the value of the setting item with the limit value stored in the limit value storage table, and determines whether the value of the setting item exceeds any of the stored limit values. To do. If this determination is YES, the process moves to a step S205, and if NO, the process moves to a step S202.

  In step S205, the CPU 1010 performs measurement under the limit value based on the limit value measurement time in the optimum value search table, and monitors whether the measurement value is within the limit value. Thereafter, the CPU 1010 advances the processing to step S206.

  In step S206, the CPU 1010 stores the limit value. That is, the limit value stored in the limit value storage table is stored as a search result. Thereafter, the CPU 1010 advances the processing to step S207.

  In step S207, the CPU 1010 determines whether limit values have been obtained for all directions. That is, based on the change direction of the optimum value search table, it is determined whether all the change directions of the setting items have been measured. If this determination is YES, the process ends, and the process returns to the step following the step that moves to the present process. If this determination is NO, the process proceeds to step S201.

  FIG. 8 is a flowchart showing the contents of limit value prediction processing of the optimum value search apparatus 10 according to an embodiment of the present invention.

  In step S301, the CPU 1010 obtains a quadratic curve. More specifically, the CPU 1010 obtains a quadratic curve that approximates the measurement value based on the value of the setting item stored for each measurement and the measurement value measured while performing the sweep measurement. Thereafter, the CPU 1010 advances the processing to step S302.

  In step S302, the CPU 1010 obtains an inclination. More specifically, the CPU 1010 obtains the inclination based on the current value on the obtained quadratic curve and the previous value. Thereafter, the CPU 1010 shifts the processing to step S303.

  In step S303, the CPU 1010 obtains a straight line. More specifically, the CPU 1010 obtains a straight line having the obtained slope and the measured value at the initial value of the setting item as an intercept. Thereafter, the CPU 1010 advances the processing to step S304.

  In step S304, the CPU 1010 obtains an intersection with the limit value. More specifically, the CPU 1010 obtains the value of the setting item when the measured value becomes the limit value by the obtained straight line representing the relationship between the value of the setting item and the measured value. Thereafter, the CPU 1010 advances the processing to step S305.

  In step S305, the CPU 1010 determines whether the inclination is larger than the previous time. That is, the CPU 1010 compares the inclination obtained this time with the inclination obtained last time, and determines whether or not the inclination obtained this time is larger than the inclination obtained last time. If the determination is YES, the process proceeds to step S306. If the determination is NO, the process ends, and the process returns to the next step after the process proceeds to the present process.

  In step S306, the CPU 1010 predicts the limit value. More specifically, the CPU 1010 sets the limit value stored in the limit value storage table as the predicted limit value. Thereafter, the CPU 1010 ends the process, and returns to the step next to the step that moves to the present process.

FIG. 9 is a diagram illustrating that the optimum value search apparatus 10 according to an embodiment of the present invention predicts a limit value. The example of FIG. 9 is an example showing a graph in which the exhaust temperature is measured while changing the torque, and the time is plotted on the horizontal axis as time (seconds), and the vertical axis as the exhaust temperature and torque .

  In FIG. 9, the actually measured torque 101 indicating a change in torque increases from the initial value, and the actually measured exhaust temperature 102 indicating a change in exhaust temperature increases with an increase in the torque value. The slope obtained based on the quadratic curve 111 approximating the actually measured exhaust temperature, and the intersections 121 and 122 at which the straight line with the initial value as an intercept intersects the limit value line 131 are shown. FIG. 9 shows that the torque change is stopped when the intersection 122 between the straight line 112 having the maximum slope and the limit value line 131 is exceeded, and that the measured exhaust gas temperature is increasing thereafter. Show.

  FIG. 10 is a diagram showing the contents when the optimum value search apparatus 10 according to an embodiment of the present invention obtains a limit value.

  FIG. 10A shows a direction in which the setting item is changed when the optimum value search apparatus 10 obtains a limit value. For example, when the setting items are common rail pressure and injection, the limit value is obtained by changing the value of the setting item from the center value based on the experimental design method to the predicted limit value in 8 directions. ing. The range up to the obtained limit value is the search range for the optimum value of the setting item. For example, the eight directions include a direction 201 for increasing only the common rail pressure, a direction 202 for increasing the common rail pressure and increasing the injection, a direction 203 for increasing only the injection, a direction 204 for decreasing the common rail pressure and increasing the injection, and the common rail. A direction 205 in which only the pressure is decreased, a direction 206 in which the common rail pressure is decreased and the injection is decreased, a direction 207 in which only the injection is decreased, and a direction 208 in which the common rail pressure is increased and the injection is decreased.

  FIG. 10B shows a process of changing the setting item when the optimum value search apparatus 10 obtains the limit value. The optimum value search apparatus 10 starts measurement from the center point where the initial measurement is performed with the center value based on the experimental design, changes the setting item to the predicted limit value (line 210), and changes the setting item based on the limit value. Is stopped to monitor that the measured value does not exceed the limit value (line 211), and then the value of the setting item is returned to the value of the center point (line 212).

  FIG. 11 is another diagram showing that the optimum value search apparatus 10 according to an embodiment of the present invention predicts a limit value. The example of FIG. 11 is an example showing that NOx is measured while changing the common rail pressure and the injection, and the common rail pressure and the limit value of the injection are predicted.

  In FIG. 11 (1), it is shown that the change of the setting item is started from the line 311 indicating the center point. In FIG. 11 (1), the shaded area represents a portion measured after the start. FIG. 11 (2) shows that the line 303 indicating NOx increases in response to the increase in the line 301 indicating the common rail pressure and the line 302 indicating the injection. A line 312 indicating the predicted limit point indicates that the change in the common rail pressure and the change in the injection are stopped. In FIG. 11 (2), the hatched portion indicates a portion measured after the stop. FIG. 11 (3) monitors that the measured value of NOx does not exceed the limit value until the limit value measurement time (line 313) of the optimum value search table after stopping the change of the common rail pressure and the change of the injection. It shows that you are doing. In FIG. 11 (3), the hatched portion indicates a portion measured after the limit value measurement time.

  FIG. 12 is a diagram showing limit values searched by the optimum value search apparatus 10 according to an embodiment of the present invention. The example of FIG. 12 represents the measured values of NOx measured while changing the common rail pressure and the injection as contour lines.

  FIG. 12 (1) is a two-dimensional view showing the contour lines of NOx with respect to common rail pressure and injection. Limit points 401 to 408 predicted and searched by the optimum value search apparatus 10 are shown. 12 (2) is a three-dimensional view of FIG. 12 (1) showing the contour lines of NOx with respect to common rail pressure and injection. Limit points 401 to 408 predicted and searched by the optimum value search apparatus 10 are shown.

  According to the present embodiment, the optimum value search device 10 measures the measurement item when the ECU control is performed at the initial value of the setting item, and continuously measures the measurement item while sweeping the setting item. Obtains a quadratic curve that fits a series of changes in measurement values during measurement while measuring and sweeping, a straight line with the maximum value of the slope of the obtained quadratic curve as the slope and the measured value at the initial value as an intercept, and ECU control An intersection point with a predetermined limit value of the measurement item is obtained, and the obtained intersection point is predicted as a limit value.

  Then, the optimum value search device 10 performs measurement until a predetermined time in the predicted limit value, monitors the fact that the predetermined limit value is not exceeded, sets the predicted limit value as the limit value, and in different directions of the sweep. , Repeat the steps from the initial measurement step to the limit value, and repeat the measurement to obtain a range based on multiple limit values, and measure the measurement item while changing the setting item within the calculated range. Find the value.

  Further, setting items for ECU control are combined, a limit value is obtained for the combined setting item, and an optimum value is obtained within the range of the obtained limit value. Therefore, the optimum value search apparatus 10 can quickly obtain the optimum value for the setting item of the control item having a delay element among the ECU control items.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to embodiment mentioned above. The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

It is a figure which shows the characteristic of this invention. It is a functional block diagram which shows the function of the optimal value search apparatus 10 which concerns on one Embodiment of this invention. It is a figure which shows an example of the hardware constitutions of the optimal value search apparatus 10 which concerns on one Embodiment of this invention. It is a figure which shows the table for optimal value search of the optimal value search apparatus 10 which concerns on one Embodiment of this invention. It is a figure which shows the limit value storage table of the optimal value search apparatus 10 which concerns on one Embodiment of this invention. It is a flowchart which shows the processing content of the optimal value search apparatus 10 which concerns on one Embodiment of this invention. It is a flowchart which shows the content of the limit range process of the optimal value search apparatus 10 which concerns on one Embodiment of this invention. It is a flowchart which shows the content of the limit value prediction process of the optimal value search apparatus 10 which concerns on one Embodiment of this invention. It is a figure which shows that the optimal value search apparatus 10 which concerns on one Embodiment of this invention is predicting a limit value. It is a figure which shows the content in case the optimal value search apparatus 10 which concerns on one Embodiment of this invention calculates | requires a limit value. It is another figure which shows that the optimal value search apparatus 10 which concerns on one Embodiment of this invention is predicting a limit value. It is a figure which shows the limit value which the optimal value search apparatus 10 which concerns on one Embodiment of this invention searched.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optimal value search apparatus 11 Initial measurement part 12 Sweep measurement part 13 Quadratic curve calculation part 14 Prediction part 15 Limit point search part 16 Range determination part 17 Optimal value search part

Claims (3)

In the ECU control of the engine, the optimum value of the setting item for causing the value of the measurement item to be the closest value to the preset target value is swept from the predetermined initial value to the limit value. It is a method to search between,
In the initial value of the setting item, an initial measurement step of measuring a measurement item when the ECU control is performed,
A sweep measurement step of measuring the measurement item while continuously sweeping the setting item;
Obtaining a quadratic curve that fits a change in a series of measurement values in the initial measurement step and the sweep measurement step;
The intersection of the straight line having the maximum slope of the obtained quadratic curve as the slope and the measured value of the initial measurement step as an intercept and the predetermined limit value of the measurement item of the ECU control is obtained, and the obtained intersection Predicting the limit value as
The predicted limit value is measured until a predetermined time, and the predicted limit value is set as a limit value by monitoring that the predetermined limit value is not exceeded.
For the different directions of the sweep, repeating the step of setting the limit value from the initial measurement step, determining a range by a plurality of the limit values determined by repeating;
Measuring the measurement item while further changing the setting item within the determined range, and obtaining an optimum value of the setting item;
Including methods. The method combines the setting item for the ECU control, setting items that combines calculated the limit value, the method according to claim 1, within the limits determined obtaining the optimum value. In the ECU control of the engine, the optimum value of the setting item for causing the value of the measurement item to be the closest value to the preset target value is swept from the predetermined initial value to the limit value. An optimum value search device for searching between,
Initial measurement means for measuring a measurement item when the ECU control is performed at an initial value of the setting item;
A sweep measuring means for measuring the measurement item while continuously sweeping the setting item;
A quadratic curve calculating means for obtaining a quadratic curve that fits a change in a series of measured values in the initial measuring means and the sweep measuring means;
Finding the intersection of a straight line with the maximum value of the slope of the obtained quadratic curve as the slope and the measured value of the initial measurement means as an intercept, and the predetermined limit value of the measurement item of the ECU control, the obtained intersection Predicting means for predicting the value as the limit value;
In the predicted limit value, until the predetermined time is measured, the limit point exploration means which sets the predicted limit value as a limit value by monitoring that the predetermined limit value is not exceeded,
For the different directions of the sweep, repeatedly determining the limit value by the limit point search means from the measurement by the initial measurement means, and a range determination means for determining the range by the plurality of limit values obtained by repeating,
Optimum value searching means for measuring the measurement item while further changing the setting item within the determined range, and obtaining an optimum value of the setting item;
An optimum value searching apparatus comprising:

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