JP2010019725A - Method and system for automatic measurement of engine characteristic parameter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the total measuring time shorter than usual on the occasion of automatic measurement of an engine characteristic parameter at many measuring points. <P>SOLUTION: Many measuring points are disposed in a controllable operation area of an engine and combustion stability is evaluated at each measuring point. Based on the evaluation value, a waiting time (combustion stabilization waiting time) T1 till a state of combustion becomes stable at each measuring point and a measuring time (parameter measuring time) T2 necessary for ensuring the accuracy of averaging processing of measured values of the engine characteristic parameter are calculated, and measurement of the engine characteristic parameter is started at each measuring point after the combustion stabilization waiting time T1 passes. Then a process wherein measurement at this measuring point is finished after passing of the parameter measuring time T2 and the measurement is transferred to the next measuring point is executed in turn for all of the measuring points. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an engine characteristic parameter automatic measurement method and an automatic measurement system for measuring predetermined engine characteristic parameters at a plurality of measurement points arranged in an engine controllable operating region.

  Engine control systems, which have become increasingly electronically controlled in recent years, are designed to improve output, reduce exhaust emissions, and reduce fuel consumption by controlling control parameters such as ignition timing and injection timing to optimal values according to operating conditions using an in-vehicle computer. And so on. Since the optimal value of the map data of the engine control parameter differs for each engine model, it is necessary to adapt the map data of the control parameter so as to satisfy the target performance in the development process.

  The conventional adaptation method is, for example, within the controllable operating range of the engine as described in Patent Document 1 (Japanese Patent Laid-Open No. 2004-263680) and Patent Document 2 (Japanese Patent Laid-Open No. 2007-9808). All measurements are performed by arranging a large number of measurement points, changing the engine operating condition to one of the measurement points, and measuring engine characteristic parameters (for example, torque, exhaust emission, fuel consumption, etc.) at the measurement points. The points are executed in order, and a map is created by calculating an appropriate value of the control parameter that optimizes the engine performance based on the measurement value at each measurement point.

In this calibration process, in order to ensure the measurement accuracy of the engine characteristic parameters at each measurement point, the engine characteristic parameter measurement is started after waiting for the combustion state to stabilize after changing the operating conditions at each measurement point. Time measurement is performed and the measurement values are averaged to obtain an average measurement value at each measurement point. In the conventional measurement method, it is necessary to ensure the waiting time until the combustion state stabilizes at each measurement point (hereinafter referred to as “combustion stabilization waiting time”) and the accuracy of the averaging process of the measured values of the engine characteristic parameters. The measurement time (hereinafter referred to as “parameter measurement time”) is set to a predetermined time uniformly determined in advance at all measurement points.
JP 2004-263680 A Japanese Patent Laid-Open No. 2007-9808

  However, since the operating conditions are changed for each measurement point, the combustion stability at each measurement point is different and the variation range of the measurement value at each measurement point is also different. If the combustion stability at each measurement point is different, the combustion stabilization waiting time until the combustion state at each measurement point is stabilized is different. Similarly, if the variation width of the measurement value at each measurement point is different, the measurement at each measurement point is measured. The parameter measurement time required to ensure the accuracy of the value averaging process also varies.

  Considering this point, in the past, when setting the combustion stabilization waiting time and parameter measurement time, in order to ensure the combustion stability and accuracy of measurement value averaging at all measurement points, Set the combustion stabilization wait time for measurement points with poor combustion stability to the combustion stabilization wait time common to all measurement points, and set the parameter measurement time for the measurement point with the largest variation in measured values to the parameter measurement time common to all measurement points. (In general, the measurement point with the lowest combustion stability is also the measurement point with the largest variation width of the measurement value).

  However, in this case, at the measurement point with the better combustion stability, the start of measurement is delayed for a longer time than necessary. Similarly, at the measurement point with the smaller measurement value variation width, it is longer than necessary. As a result, there is a problem that the total measurement time required for measurement of all measurement points becomes long. In particular, the number of control parameters to be adapted increases in recent electronically controlled engines, and the number of measurement points increases exponentially due to complex changes in the operating state depending on the combination of these control parameters. For this reason, increasing the total measurement time has become an increasingly serious problem in recent years.

  The present invention has been made in consideration of such circumstances. Therefore, the object of the present invention is to provide an automatic measurement method and automatic measurement method for engine characteristic parameters that can shorten the total measurement time required for measurement of all measurement points. To provide a measurement system.

  In order to achieve the above object, according to the first aspect of the present invention, a plurality of measurement points are arranged in an operation region where the engine can be controlled, and the engine rotational speed, engine load and / or ignition timing, injection timing, and the like are controlled. Automatic engine characteristic parameter processing in which a parameter (hereinafter referred to as “operating condition”) is changed to a condition at any measurement point and a predetermined engine characteristic parameter at that measurement point is measured in order for all measurement points. In the measurement method, the combustion stability is evaluated at each measurement point, and the waiting time until the combustion state is stabilized at each measurement point based on the evaluation value (hereinafter referred to as “combustion stabilization wait time”) and / or engine characteristics. Calculate the measurement time (hereinafter referred to as “parameter measurement time”) required to ensure the accuracy of the parameter measurement value averaging process, and follow the calculation result. It is obtained so as to measure the engine characteristic parameter Te.

  In this automatic measurement method, the combustion stability is evaluated at each measurement point, and the combustion stabilization wait time and / or parameter measurement time is calculated based on the evaluation value. The parameter measurement time can be set to an appropriate time according to the combustion state at each measurement point, and the total measurement time can be shortened as compared with the prior art. In this case, if the combustion stability is evaluated using the waiting time until the combustion state is stabilized at each measurement point, the time for evaluating the combustion stability is from the start of the combustion stability evaluation at each measurement point. It does not become a factor to lengthen the time to start measurement.

  Further, as in claim 2, when evaluating the combustion stability at each measurement point, the standard deviation of the indicated mean effective pressure, the standard deviation of the shaft torque, the variation of the combustion pressure, and the engine rotation fluctuation amount within a predetermined time. The combustion stability may be evaluated based on at least one of the air-fuel ratio fluctuation amount of the exhaust gas, the combustion ion current fluctuation amount, and the ratio of any of these and the average value thereof.

  Further, as described in claim 3, any one of a map, a mathematical expression, and a model that prescribes a relationship between the evaluation value of the combustion stability at each measurement point and the combustion stabilization waiting time and / or parameter measurement time is set in advance. The combustion stabilization waiting time and / or the parameter measurement time may be calculated using any one of the map, the mathematical formula, and the model. Thereby, the combustion stabilization waiting time and / or parameter measurement time can be calculated with high accuracy.

  According to a fourth aspect of the present invention, any one of the map, the mathematical expression, and the model may be corrected by an operator according to the model of the engine to be measured. In this way, maps, formulas, and models can be modified according to the specific characteristics of each engine model, and the combustion stabilization waiting time and / or parameter measurement time can be set with higher accuracy. Measurement accuracy can be further improved.

  Further, as in claim 5, it is preferable to calculate the combustion stabilization waiting time and / or parameter measurement time in real time based on the evaluation value of combustion stability at each measurement point. The calculation of the combustion stabilization waiting time and / or parameter measurement time can be performed in real time by a computer using the combustion stabilization waiting time.

  In this case, as in the sixth aspect, the combustion stability waiting time may be counted after the combustion stability is evaluated at each measurement point.

  Alternatively, as described in claim 7, after the combustion stability is evaluated at each measurement point, counting of the combustion stability waiting time is started, and thereafter, the time required for the evaluation of the combustion stability is calculated from the combustion stabilization waiting time. Measurement of the engine characteristic parameter may be started when the subtracted time has elapsed.

  Alternatively, as described in claim 8, counting of the combustion stabilization waiting time may be started simultaneously with the start of evaluation of combustion stability at each measurement point.

  In this case, if the combustion stabilization waiting time is shorter than the time required for the combustion stability evaluation as in claim 9, the engine characteristic parameter is measured immediately after the combustion stability evaluation is completed. Good to start.

  The invention according to claim 10 is an invention in which the technical idea of the method invention according to claim 1 is expressed as an “automatic measurement system” of a different category, and the same effect as in claim 1 can be obtained.

  Hereinafter, three Examples 1 to 3 embodying the best 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 engine characteristic parameter automatic measurement system will be described with reference to FIG. An engine 12 to be measured is attached to the engine bench 11, and various sensor signals such as cooling water temperature, engine speed, throttle opening, accelerator opening, air-fuel ratio, etc. detected by various sensors attached to the engine 12 are received. It is transmitted to the engine ECU 13. The engine ECU 13 detects the operating state of the engine 11 based on the received various sensor signals, and outputs an engine control signal such as an ignition timing and a fuel injection amount to the engine 12 according to the engine operating state. Control the operating state.

  The engine bench control tool 14 for controlling the engine bench 11 is an engine characteristic parameter (hereinafter referred to as “measurement”) such as combustion analysis data, exhaust emission, and exhaust gas air-fuel ratio measured by various measuring devices such as the combustion analysis device 15 and the exhaust gas analyzer 16. Parameter)), the engine speed and the engine load are changed when the measurement point is changed, and a control parameter change instruction is transmitted to the ECU-compatible tool 17 from the ECU-compatible tool 17. The parameter writing instruction is transmitted to The RAM value is transmitted from the engine ECU 13 to the ECU compatible tool 17, and the RAM value received by the ECU compatible tool 17 is transmitted to the engine bench control tool 14.

  The engine bench control tool 14 transmits an instruction parameter request to the automatic adjustment tool 18 and receives a parameter instruction transmitted from the automatic adjustment tool 18. The automatic adaptation tool 18 receives the instruction parameter request, determines the measurement end of the current measurement point, and proceeds to the next measurement point. The engine bench control tool 14 and the automatic adaptation tool 18 are configured by a personal computer or the like, execute various routines described later, evaluate combustion stability at each measurement point, and evaluate each combustion point based on the evaluation value. The waiting time until the combustion state stabilizes (hereinafter referred to as “combustion stabilization waiting time”) T1 and the measurement time required to ensure the accuracy of the measurement parameter averaging process (hereinafter referred to as “parameter measurement time”) ) A process of calculating T2, starting measurement of the measurement parameter at each measurement point after the combustion stabilization waiting time T1 has elapsed, and ending the measurement at the measurement point after the parameter measurement time T2 has elapsed, and moving to the next measurement point Are sequentially executed for all measurement points. The processing contents of each routine will be described below.

  The automatic measurement main routine of FIG. 2 is executed by the automatic calibration tool 18. When this program is started, first, in step 101, a list of operating conditions to be measured this time is input to the automatic adaptation tool 18. Thereafter, the process proceeds to step 102 where automatic measurement is started by the automatic adaptation tool 18.

  During automatic measurement, in step 103, the list of operating conditions is referred to, and the operating conditions corresponding to the current measurement point are transmitted to the engine bench control tool 14. In the next step 104, the automatic measurement subroutine of FIG. 3 is executed, combustion stability is evaluated at the current measurement point, combustion stabilization waiting time T1 and parameter measurement time T2 are calculated based on the evaluation values, and combustion is performed. Measurement parameter measurement starts after the stabilization waiting time T1 has elapsed, and this measurement ends after the parameter measurement time T2 has elapsed. Thereafter, the process proceeds to step 105, where it is determined whether or not measurement of all measurement points has been completed. If there are measurement points that have not yet been measured, the process proceeds to step 106, and the process proceeds to the next measurement point. , The above-described steps 103 to 105 are repeated. Thereafter, when it is determined in step 105 that measurement of all measurement points has been completed, the main routine is terminated.

  The automatic measurement subroutine of FIG. 3 is executed by the engine bench control tool 14 in step 104 of the automatic measurement main routine of FIG. When this subroutine is started, first, at step 111, the engine bench control tool 14 receives the engine rotation speed and the engine load in accordance with the operating conditions of the current measurement point received from the automatic calibration tool 18 at step 103 in FIG. And an instruction to change the control parameter is input to the ECU fitting tool 17. Thereby, the ECU compatible tool 17 executes the RAM value rewriting routine of FIG. 4 and rewrites the RAM value of the engine ECU 13 (step 120).

  Thereafter, the process proceeds to step 112 in FIG. 3, and the combustion stability determination routine in FIG. 5 is executed to evaluate the combustion stability. When the combustion stability determination routine of FIG. 5 is started, first, at step 121, counting of the combustion stability determination time T0 is started, and at the next step 122, measurement of data for evaluating the combustion stability is started. At this time, the data for evaluating the combustion stability include, for example, the standard deviation of the indicated mean effective pressure, the standard deviation of the shaft torque, the variation of the combustion pressure, the engine rotation fluctuation amount, the exhaust gas air-fuel ratio fluctuation amount, and the combustion ion current. Any one of the fluctuation amounts may be used, or any one of these and the ratio of the average value may be used. For example, the combustion stability can be accurately evaluated by using the standard deviation / average value of the indicated mean effective pressure or the standard deviation / average value of the shaft torque. The relationship that the standard deviation of the indicated mean effective pressure, the standard deviation of the shaft torque, the fluctuation of the combustion pressure, the fluctuation amount of the engine rotation, the fluctuation amount of the air-fuel ratio of the exhaust gas, the fluctuation amount of the combustion ion current becomes smaller as the combustion stability becomes stable. Therefore, combustion stability can be evaluated from these data. The process of step 112 serves as a combustion stability evaluation means in the claims.

  Thereafter, the process proceeds to step 123, where it is determined whether or not a predetermined combustion stability determination time T0 has elapsed since the start of measurement of combustion stability, and the processing of steps 121 to 123 is performed until the combustion stability determination time T0 has elapsed. repeat. Here, the combustion stability determination time T0 may be set in advance for each measurement point, or a uniform time common to all measurement points may be set. Then, when the combustion stability determination time T0 has elapsed, the routine proceeds to step 124, where the evaluation value of the combustion stability at the current measurement point is determined.

  Thereafter, the routine returns to step 113 in FIG. 3, and the combustion stabilization wait time / parameter measurement time calculation routine in FIG. 6 or 7 is executed to calculate the combustion stabilization wait time T1 and the parameter measurement time T2 at the current measurement point. . In the combustion stabilization waiting time / parameter measurement time calculation routine (example 1) in FIG. 6, first, in step 131, a map that defines the relationship between the combustion stability evaluation value and the combustion stabilization waiting time at each measurement point is referred to. Then, the combustion stabilization waiting time T1 corresponding to the evaluation value of the combustion stability at the current measurement point is calculated.

  In the next step 132, the parameter measurement corresponding to the evaluation value of the combustion stability at the current measurement point is referred to with reference to a map that defines the relationship between the evaluation value of the combustion stability at each measurement point and the parameter measurement time. Time T2 is calculated. At this time, the map may be corrected by the operator according to the model of the engine to be measured. In this way, the map can be modified in accordance with the unique characteristics of each model of the engine 12, so that the combustion stabilization waiting time T1 and the parameter measurement time T2 can be set with higher accuracy, and the measurement accuracy Can be further improved.

  Further, in the combustion stabilization wait time / parameter measurement time calculation routine (example 2) of FIG. 7, first, in step 141, a mathematical formula (or a formula that defines the relationship between the combustion stability evaluation value and the combustion stabilization wait time at each measurement point) Model) is used to calculate combustion stabilization waiting time T1 corresponding to the evaluation value of combustion stability at the current measurement point.

  Then, in the next step 142, using the mathematical formula (or model) that defines the relationship between the combustion stability evaluation value and the parameter measurement time at each measurement point, the combustion stability evaluation value at this measurement point is handled. The parameter measurement time T2 to be calculated is calculated. At this time, the mathematical formula (or model) may be corrected by the operator according to the model of the engine 12 to be measured. In this way, the mathematical formula (or model) can be modified in accordance with the unique characteristics of each model of the engine 12, so that the combustion stabilization waiting time T1 and the parameter measurement time T2 can be set with higher accuracy. Measurement accuracy can be further improved. The combustion stabilization waiting time / parameter measurement time calculation routine of FIG. 6 or FIG. 7 serves as calculation means in the claims.

  After calculating the combustion stabilization waiting time T1 and the parameter measurement time T2 as described above, the process returns to step 114 in FIG. 3 to start counting the combustion stabilization waiting time T1. Thereafter, the routine proceeds to step 115, where it is determined whether or not the combustion stabilization waiting time T1 has elapsed since the end of the evaluation of combustion stability (when the calculation of the combustion stabilization waiting time T1 and parameter measurement time T2 is completed), Wait until time T1 has elapsed.

  Thereafter, when the combustion stabilization waiting time T1 has elapsed, the routine proceeds to step 116, where measurement of measurement parameters is started. In the next step 117, counting of the parameter measurement time T2 is started, and in the subsequent step 118, the measurement values of the measurement parameters are averaged. Here, in the averaging process, an arithmetic average value of the measurement values may be calculated, or an average value of the measurement values may be calculated by an annealing process. Alternatively, the median value or the mode value of the measurement values within the parameter measurement time T2 may be calculated. Thereafter, the process proceeds to step 119, where it is determined whether or not the parameter measurement time T2 has elapsed from the start of measurement of the measurement parameter, and the processing of steps 117 to 119 is repeated until the parameter measurement time T2 has elapsed. Thereafter, when the parameter measurement time T2 has elapsed, the measurement at the current measurement point is terminated. At this time, the engine bench control tool 14 transmits an instruction parameter change request to the automatic adaptation tool 18 to notify the end of the current measurement point.

  Until the parameter measurement time T2 elapses, only measurement parameters are measured and the measured values are stored in the memory. When the parameter measurement time T2 elapses, the measurement values accumulated in the memory are averaged. You may make it process. The processing in these steps 116 to 118 serves as a measuring means in the claims.

The effect of the automatic measurement method of the first embodiment described above will be described with reference to FIG.
In the first embodiment, the combustion stability is evaluated at each measurement point, and the combustion stabilization waiting time T1 and the parameter measurement time T2 are calculated based on the evaluation values. Therefore, the combustion stabilization waiting time T1 for each measurement point, respectively. The parameter measurement time T2 can be set to an appropriate time according to the combustion state at each measurement point. As a result, for example, at a measurement point with a good combustion state or a measurement point with a slightly poor combustion state, the combustion stabilization waiting time T1 and parameter measurement time T2 can be shortened compared to the conventional method, and the total measurement time can be reduced compared with the conventional method. It can be shortened.

In the first embodiment described above, after a predetermined combustion stability determination time T0 has elapsed from the start of measurement of combustion stability at each measurement point (that is, combustion stability is evaluated, combustion stabilization waiting time T1 and parameter measurement time T2). Since the counting of the combustion stabilization waiting time T1 is started after the time T0 required for calculating the time has elapsed), the time required to measure one measurement point is the combustion stability determination time T0 and the combustion time. This is the total time of the stabilization waiting time T1 and the parameter measurement time T2.
Time required to measure one measurement point = T0 + T1 + T2

  Since the calculation of the combustion stabilization waiting time T1 and the parameter measurement time T2 is instantaneously executed by a computer, the time required for these calculations is negligibly small when compared with the time required for evaluating the combustion stability. Therefore, the time T0 required for evaluating the combustion stability and calculating the combustion stabilization waiting time T1 and the parameter measurement time T2 is substantially the same as the time required for evaluating the combustion stability. Therefore, in the following description, T0 is simply referred to as “time required for evaluating combustion stability”.

On the other hand, in the second embodiment of the present invention shown in FIGS. 9 and 10, the combustion stability waiting time T1 starts counting after the combustion stability is evaluated at each measurement point, and then this combustion stabilization waiting time T1. The measurement parameter measurement is started when the corrected combustion stabilization waiting time (T1 -T0) obtained by subtracting the time T0 required for evaluating the combustion stability from has elapsed. Accordingly, the time required for measurement at one measurement point is the sum of the combustion stability determination time T0, the corrected combustion stabilization waiting time (T1 -T0), and the parameter measurement time T2, so that one time is eventually obtained. The time required for measuring the measurement point is the total time of the combustion stabilization waiting time T1 calculated based on the combustion stability evaluation value and the parameter measurement time T2.
Time required for measuring one measuring point = T0 + (T1-T0) + T2
= T1 + T2

  If the corrected combustion stabilization waiting time (T1-T0) is a negative value, that is, if the combustion stabilization waiting time T1 is shorter than the combustion stability determination time T0, the time when the combustion stability determination time T0 has passed ( Measurement of the measurement parameter may be started immediately when the combustion stability is evaluated and the combustion stabilization waiting time T1 and the parameter measurement time T2 are calculated.

  The automatic measurement subroutine of FIG. 9 executed in the second embodiment is obtained by changing the process of step 115 of the automatic measurement subroutine of FIG. 3 to steps 114a and 115a. The same.

That is, in the automatic measurement subroutine of FIG. 9, in steps 112 and 113, the combustion stability is evaluated and the combustion stabilization waiting time T1 and the parameter measurement time T2 are calculated. Then, the process proceeds to step 114 and the combustion stabilization waiting time T1 is counted. Then, in the next step 114a, the corrected combustion stabilization waiting time (T1 -T0) is obtained by subtracting the time T0 required for evaluating the combustion stability from the combustion stabilization waiting time T1.
Combustion stabilization wait time after correction = T1-T0

  Thereafter, the routine proceeds to step 115a, and whether or not the corrected combustion stabilization waiting time (T1-T0) has elapsed since the end of the evaluation of combustion stability (when calculation of the combustion stabilization waiting time T1 and parameter measurement time T2 is completed). And wait until the corrected combustion stabilization waiting time (T1-T0) elapses.

  Thereafter, when the corrected combustion stabilization waiting time (T1−T0) has elapsed, the process proceeds to step 116, where measurement of the measurement parameter is started. Thereafter, when the parameter measurement time T2 has elapsed, the current measurement point is measured. The measurement is finished (steps 117 to 119).

  When the combustion stabilization waiting time T1 is shorter than the combustion stability determination time T0, when the combustion stability is evaluated and the combustion stabilization waiting time T1 and the parameter measurement time T2 are calculated, the process proceeds to step 115a. “Yes” is determined, and the process immediately proceeds to step 116 to start measurement of the measurement parameter.

  In the second embodiment described above, the combustion stability waiting time T1 is counted after the combustion stability is evaluated at each measurement point, and then the time T0 required for evaluating the combustion stability from the combustion stabilization waiting time T1. Since the measurement parameter measurement is started when the corrected combustion stabilization waiting time (T1 -T0) obtained by subtracting is passed, measurement of one measurement point is performed as compared with the first embodiment. There is an advantage that the time required for this can be shortened by the combustion stability determination time T0.

In the third embodiment of the present invention shown in FIGS. 11 and 12, counting of the combustion stabilization waiting time T1 is started at the same time when evaluation of combustion stability is started at each measurement point, and combustion is started from the start of evaluation of combustion stability. When the stabilization waiting time T1 has elapsed, measurement of measurement parameters is started. In this case, the combustion stabilization waiting time T1 is not yet determined at the start of counting the combustion stabilization waiting time T1, but in general, the combustion stabilization waiting time T1 until the combustion state is stabilized is used for evaluating the combustion stability. Since the required combustion stability determination time T0 is longer, the combustion stability determination time T0 elapses before the combustion state is stabilized, and the combustion stabilization waiting time T1 is determined. As a result, the time required to measure one measurement point is the sum of the combustion stabilization waiting time T1 and the parameter measurement time T2.
Time required to measure one measurement point = T1 + T2

  If the combustion stabilization waiting time T1 is shorter than the combustion stability determination time T0, the measurement parameter measurement is started immediately after the combustion stability determination time T0 has elapsed (when the combustion stability evaluation is completed). It ’s fine.

  In the automatic measurement subroutine of FIG. 11 executed in the third embodiment, the process of step 114 of the automatic measurement subroutine of FIG. 3 is omitted, and the process of step 110 is added before step 111. The processing of each step is the same as that in FIG.

  That is, when the automatic measurement subroutine of FIG. 11 is started, first, at step 110, the counting of the combustion stabilization waiting time T1 is started, the combustion stability is evaluated, and the combustion stabilization waiting time T1 and the parameter measurement time T2 are calculated. Calculate (steps 112 and 113). Then, in the next step 115, it is determined whether or not the combustion stabilization waiting time T1 has elapsed from the start of the evaluation of combustion stability, and measurement of measurement parameters is started when the combustion stabilization waiting time T1 has elapsed ( Step 116) After that, when the parameter measurement time T2 has elapsed, the measurement of the current measurement point is terminated (Steps 117 to 119).

  When the combustion stabilization waiting time T1 is shorter than the combustion stability determination time T0, when the combustion stability is evaluated and the combustion stabilization waiting time T1 and the parameter measurement time T2 are calculated, the routine proceeds to step 115. “Yes” is determined, and the process immediately proceeds to step 116 to start measurement of the measurement parameter.

  In the third embodiment described above, the combustion stability waiting time T1 starts counting at the same time when the combustion stability evaluation is started at each measurement point, and the combustion stability waiting time T1 has elapsed from the start of the combustion stability evaluation. Since the measurement parameter measurement is started at this point, the time required to measure one measurement point is set to the combustion stability determination time T0 minutes as compared with the first embodiment, as in the second embodiment. There is an advantage that can only be shortened.

  In each of the first to third embodiments, both the combustion stabilization waiting time T1 and the parameter measurement time T2 are calculated based on the evaluation value of the combustion stability at each measurement point, but only one of them is calculated. Thus, the other may be set to a predetermined fixed time. Even in this case, the total measurement time can be shortened as compared with the conventional case.

It is a block diagram which shows the structure of the automatic measurement system of the engine characteristic parameter used in each Examples 1-3 of this invention. 3 is a flowchart illustrating a flow of processing of an automatic measurement main routine according to the first embodiment. 3 is a flowchart showing a flow of processing of an automatic measurement subroutine of Example 1. 6 is a flowchart illustrating a flow of processing of a RAM value rewriting routine according to the first embodiment. 3 is a flowchart showing a flow of processing of a combustion stability determination routine of Embodiment 1. 6 is a flowchart showing a flow of processing of a combustion stabilization waiting time / parameter measurement time calculation routine (Example 1) of Embodiment 1. 6 is a flowchart showing a flow of processing of a combustion stabilization waiting time / parameter measurement time calculation routine (Example 2) of Embodiment 1. It is a figure explaining the effect of the automatic measurement method of the engine characteristic parameter of Example 1 as compared with the past. 10 is a flowchart showing a flow of processing of an automatic measurement subroutine of Example 2. FIG. 10 is a diagram for explaining a time required for measuring one measurement point according to the second embodiment. 10 is a flowchart showing a flow of processing of an automatic measurement subroutine of Example 3. FIG. 10 is a diagram for explaining a time required for measuring one measurement point according to the third embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Engine bench, 12 ... Engine, 13 ... Engine ECU, 14 ... Engine bench control tool, 17 ... ECU adaptation tool, 18 ... Automatic adaptation tool

Claims (10)

A plurality of measurement points are arranged within the controllable operation region of the engine, and control parameters (hereinafter referred to as “operation conditions”) such as engine rotation speed, engine load and / or ignition timing, and injection timing are set at any of the measurement points. In the automatic measurement method of engine characteristic parameters, in which the process of changing to the condition and measuring the predetermined engine characteristic parameter at the measurement point is sequentially executed for all measurement points.
The combustion stability is evaluated at each measurement point, and the waiting time until the combustion state is stabilized at each measurement point based on the evaluation value (hereinafter referred to as “combustion stabilization wait time”) and / or the measured value of the engine characteristic parameter Automatic measurement of an engine characteristic parameter characterized by calculating a measurement time (hereinafter referred to as “parameter measurement time”) necessary to ensure the accuracy of the averaging process of the engine and measuring the engine characteristic parameter according to the calculation result Method.   When evaluating the combustion stability at each measurement point, the standard deviation of the indicated mean effective pressure, the standard deviation of the shaft torque, the variation of the combustion pressure, the engine rotation fluctuation amount, the exhaust gas air-fuel ratio fluctuation amount within a predetermined time, 2. The engine characteristic parameter automatic measurement method according to claim 1, wherein combustion stability is evaluated based on at least one of a combustion ion current fluctuation amount and a ratio between any one of these and an average value thereof.   One of a map, a mathematical expression, and a model that prescribes a relationship between the evaluation value of the combustion stability at each measurement point and the combustion stabilization waiting time and / or parameter measurement time is set in advance. 3. The engine characteristic parameter automatic measurement method according to claim 1, wherein the combustion stabilization waiting time and / or parameter measurement time is calculated using any one of them.   The engine characteristic parameter automatic measurement method according to any one of claims 1 to 3, wherein any one of the map, the mathematical expression, and the model is corrected by an operator according to a model of an engine to be measured.   5. The engine characteristic parameter automatic according to claim 1, wherein the combustion stabilization waiting time and / or parameter measurement time is calculated in real time based on an evaluation value of combustion stability at each measurement point. Measurement method.   6. The method for automatically measuring engine characteristic parameters according to claim 1, wherein counting of the combustion stabilization waiting time is started after evaluating combustion stability at each measurement point.   After evaluating combustion stability at each measurement point, the counting of the combustion stability waiting time is started, and then when the time required for subtracting the time required for evaluating the combustion stability from the combustion stabilization waiting time has elapsed, 6. The engine characteristic parameter automatic measurement method according to claim 1, wherein measurement of the engine characteristic parameter is started.   6. The automatic measurement method for engine characteristic parameters according to claim 1, wherein counting of the combustion stabilization waiting time is started simultaneously with the start of evaluation of combustion stability at each measurement point.   When the combustion stabilization waiting time is shorter than the time required for the evaluation of the combustion stability, the measurement of the engine characteristic parameter is started immediately after the evaluation of the combustion stability is completed. The method for automatically measuring engine characteristic parameters according to claim 8. A plurality of measurement points are arranged within the controllable operation region of the engine, and control parameters (hereinafter referred to as “operation conditions”) such as engine rotation speed, engine load and / or ignition timing, and injection timing are set at any of the measurement points. In the automatic measurement system for engine characteristic parameters, in which the process of measuring the predetermined engine characteristic parameter at the measurement point by changing to the condition is sequentially executed for all measurement points.
Combustion stability evaluation means for evaluating combustion stability at each measurement point;
Measurements required to ensure the waiting time until the combustion state is stabilized at each measurement point and / or the accuracy of averaging the measurement values of the engine characteristic parameters based on the evaluation value of the combustion stability at each measurement point A calculation means for calculating time;
An engine characteristic parameter automatic measurement system comprising: a measurement unit that measures the engine characteristic parameter according to a calculation result of the calculation unit at each measurement point.

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