JP5293766B2 - Engine control device - Google Patents

Abstract

The device has a target combustion parameter determination circuit i.e. combustion parameters computer (32), determining combustion parameters i.e. ignition timings, that represent combustion states of fuel in an internal combustion engine (10). The combustion parameters include values of a time series parameter, where the time series parameter values are defined as time-series data represented at predetermined time points. A control instruction computer i.e. actuator controller (33), calculates instruction values based on desired values of the time-series data by using correlation data.

Description

  The present invention relates to an engine control device that controls the combustion state of an engine by controlling the operation of an actuator such as a fuel injection valve or an EGR valve, and thus controls the performance of the engine.

  Conventionally, there has been an engine control device that controls various control parameters such as fuel injection amount, injection timing, EGR amount, boost pressure, intake air amount, ignition timing, intake / exhaust valve opening / closing timing so as to satisfy desired engine performance. Are known. Examples of performance parameters representing engine performance include values related to exhaust emissions such as NOx amount and CO amount, output torque, fuel consumption rate (fuel consumption), and the like.

  In general, the command values of the control parameters such as the fuel injection amount for the engine performance are set using a control map created by a conformance test. In this case, control maps for setting command values for a plurality of control parameters (fuel injection amount, injection timing, etc.) are provided independently, and the command values of the control parameters set by these control maps are provided. Based on the above, various controls are performed so that the performance parameter becomes the target value. In this way, when the command values of the respective control parameters are set independently, when a certain performance parameter reaches the target value, another performance parameter deviates from the target value, and when the other performance parameter reaches the target value, the certain performance parameter is It is easy to fall into a situation where a plurality of performance parameters interfere with each other, such as deviation from the target value. Therefore, at present, it is difficult to simultaneously match a plurality of performance parameters with a target value.

  Further, as a prior art, a target value of a combustion parameter representing a combustion state is calculated from an engine operating state, and feedback control is performed so that the actual combustion parameter actually detected by a sensor or the like matches the target value ( Patent Document 1) and those that perform feedback control so that a target value matches a predicted value based on a simulation model (Patent Document 2).

JP 2008-223634 A JP 2007-77935 A

  However, in the prior art including the above Patent Documents 1 and 2, the target value of the combustion parameter is individually set by adaptation or calculation with respect to any performance parameter such as exhaust emission, output torque, and fuel consumption. ing. Therefore, when the deviation between the target value of the combustion parameter and the actual value is matched by feedback control, the performance parameter associated with the combustion parameter can follow the target value even if it can follow the target value. There was a possibility that a situation in which the target value was not followed could occur. That is, when performing feedback control of the combustion parameter, there is a disadvantage that mutual interference occurs with respect to a plurality of performance parameters, and as a result, the plurality of performance parameters cannot be matched with the target value at the same time.

  In addition, if there are individual differences or changes with time in the actuator, there is a concern that the engine combustion state is affected by these differences, and the engine performance control based on the combustion state is adversely affected. For example, when the injection hole of the fuel injection valve is clogged, the change waveform (combustion waveform) of the in-cylinder pressure and the heat generation rate is different from the reference waveform. In such a case, there is a possibility that a disadvantage that the desired engine performance cannot be obtained may occur.

  The present invention has been made to solve the above-mentioned problems, and its purpose is to suitably control the engine performance by improving the controllability of the combustion state of the engine, and further, individual differences and changes with time have occurred in the actuator. Another object of the present invention is to provide an engine control device that can realize suitable control reflecting the above.

  Hereinafter, means for solving the above-described problems and the effects thereof will be described.

The invention according to claim 1 is an engine control device that controls the combustion state of the engine by controlling the operation of the actuator,
Combustion target setting means for setting a target value of each combustion parameter for a plurality of combustion parameters representing the combustion state;
Using the first correlation data defining the correlation between the plurality of combustion parameters and the control parameters related to the actuator, the command value of the control parameter is calculated based on the target value of each combustion parameter set by the combustion target setting means. Control command value calculating means;
With
The plurality of combustion parameters are specific parameters that change in time series with the occurrence of combustion in the engine combustion chamber, and include time-series data that is data at a plurality of time-series points predetermined for the specific parameters. The first correlation data defines the correlation between the time series data at each time series point and the control parameter,
The combustion target setting means sets a target value of time series data at each time series point,
The control command value calculation means calculates the command value of the control parameter based on the target value of the time series data at each time series point using the first correlation data.

  In the above invention, the first correlation data includes a plurality of combustion parameters (for example, ignition timing, ignition start delay time, heat generation rate, maximum heat generation rate, etc.) and control parameters (for example, fuel injection amount, EGR amount, boost pressure). Etc.), and the correlation is such that a plurality of combustion parameters are associated with each control parameter. For example, the correlation between the ignition timing and the fuel injection amount is not simply defined on a one-to-one basis, but for a plurality of combustion parameters such as the ignition timing, the ignition start delay time, the heat generation rate, the maximum heat generation rate, etc. The fuel injection amount is defined so as to satisfy the target values of the respective combustion parameters at the same time.

  Therefore, the relationship between the control parameters is individually defined for each of the plurality of combustion parameters, and unlike the existing technology in which the command value of the control parameter is set for the convenience of each combustion parameter, the plurality of combustion parameters Can be prevented from interfering with each other, and deterioration of controllability of engine performance due to the mutual interference can be avoided. That is, by using the first correlation data, it is possible to improve the controllability with respect to simultaneously setting a plurality of combustion parameters to the target value, and thus it is possible to suitably control the engine performance. In the first aspect of the invention, it is preferable that a parameter arithmetic expression in which a correlation between a plurality of combustion parameters and a control parameter is expressed by an inverse model of the engine system is used as the first correlation data.

  By the way, among the plurality of combustion parameters, there are parameters that change in time series in accordance with the combustion of fuel in the combustion cycle of the engine. For example, in-cylinder pressure that is the pressure in the engine combustion chamber, heat generation rate in the combustion chamber, in-cylinder temperature, and the like. Assuming that individual differences and changes over time occur in the actuator, the engine combustion state is affected by these factors. In particular, the time series data (waveform data) that changes in time series with the occurrence of combustion has individual differences. It is also possible that effects due to changes over time appear. For example, assuming a fuel injection valve as the actuator, if the injection hole of the fuel injection valve is clogged, the change waveform (combustion waveform) of the in-cylinder pressure and heat generation rate will be different from the reference waveform, and the ignition timing etc. It is conceivable that the in-cylinder pressure and the heat generation rate at a predetermined time determined in accordance with the timing become small, or the timing of changes in the in-cylinder pressure and the heat generation rate shifts back and forth.

  Therefore, in the present invention, when the plurality of combustion parameters are specific parameters that change in time series with the occurrence of combustion in the engine combustion chamber, and are data at a plurality of time series points that are predetermined for the specific parameters. It is assumed that series data is included, and the first correlation data (control parameter calculation formula) defines the correlation between the time series data and the control parameter at each time series point. Then, the target value of the time series data at each time series point is set, and the command value of the control parameter is calculated based on the target value of the time series data at each time series point using the first correlation data. .

  According to the above configuration, when controlling the actuator, it is possible to calculate the command value of the control parameter by taking into account the time-series characteristics of each combustion parameter, and as a result, the fuel injection valve is caused by individual differences or changes with time. Even if there is a difference in the in-cylinder pressure and heat generation rate waveforms, the engine performance can be controlled while reflecting the difference.

  As described above, it is possible to appropriately control the engine performance by improving the controllability of the combustion state of the engine, and it is possible to realize a suitable control reflecting the individual difference and the change with time in the actuator.

  In the invention according to claim 2, time series point setting means for variably setting the number of time series points of the time series data based on an operating state of the engine, and setting of the time series points of the time series data Means for changing at least a part of the first correlation data based on the number.

  If the engine operating state is different, it is conceivable that the degree of influence due to individual differences of actuators and changes with time is different. For example, in the idle operation state, it is considered that the degree of influence due to individual differences of the actuators and changes with time is greater than in the high load operation state. In this regard, in the above configuration, the number of time-series points in the time-series data is variably set based on the operating state of the engine, so that the engine performance is controlled while taking into account the degree of influence due to individual differences in actuators and changes over time. Can be implemented.

  According to a third aspect of the present invention, the time-series point setting means variably sets the number of time-series points of the time-series data based on an engine speed, and a predetermined low rotation range and Among the high rotation regions on the high rotation side, the time series score is increased in the low rotation region than in the high rotation region.

  In this case, the control accuracy of the engine performance can be increased under a situation where the engine rotational speed is low and the degree of influence due to individual differences of actuators or changes with time tends to increase. This is advantageous even if the calculation load on the electronic control unit (ECU) is taken into account, the configuration that increases the time series score in the low rotation range (in other words, the configuration that decreases the time series score in the high rotation range). It can be said that.

  According to a fourth aspect of the present invention, the actuator is a fuel injection valve that injects fuel to the engine, and an engine control device capable of variably setting an injection mode at the time of fuel injection by the fuel injection valve. And means for changing at least a part of the first correlation data based on the set injection mode.

  There are various injection modes of the fuel injection valve, such as an injection mode in which one fuel injection is performed for one combustion, an injection mode in which a plurality of fuel injections are performed, and the like. Further, in the case of performing a plurality of fuel injections, for example, the number of times each injection divided into pilot injection, main injection, after-injection, etc., may be changed each time. In this case, when the injection mode of the fuel injection valve is different, the time-series data (combustion waveform) regarding combustion is also different. In this regard, in the above configuration, since at least a part of the first correlation data is changed in accordance with the injection mode at each time, the engine performance is controlled while taking into account the change in the time series data accompanying the change in the injection mode. it can.

  In the invention according to claim 5, the specific parameter is combustion waveform data of at least one of in-cylinder pressure, in-cylinder pressure change rate, heat generation rate, and heat generation amount in the engine combustion chamber, and fuel as the actuator The combustion waveform data at the combustion start timing of the fuel injected from the injector, the combustion waveform data at the combustion peak, and the combustion waveform data at the combustion end timing at least at each time series point It is included as series data.

  Combustion waveform data (in-cylinder pressure, in-cylinder pressure change rate, heat generation rate, heat generation amount) at the start of combustion, combustion waveform data at the combustion peak, and combustion waveform data at the end of combustion grasp the characteristics of combustion. Therefore, it is physically meaningful and reflects the effects of individual differences in actuators and changes over time. Therefore, when the performance parameter is controlled in consideration of the combustion state, individual differences and changes with time of the actuator can be favorably reflected.

  According to a sixth aspect of the present invention, performance target setting means for setting target values of each performance parameter for a plurality of performance parameters representing engine performance is provided. The combustion target setting means uses the second correlation data defining the correlation between the plurality of performance parameters and the plurality of combustion parameters, and based on the target value of each performance parameter set by the performance target setting means. The target values of the plurality of combustion parameters for each target value are calculated.

  The second correlation data includes a plurality of performance parameters (eg, NOx amount, PM amount, output torque, fuel consumption, etc.) and a plurality of combustion parameters (eg, ignition timing, ignition start delay time, heat generation rate, heat generation rate maximum time, etc.) The correlation is not a one-to-one association between performance parameters and combustion parameters, but a plurality to many. For example, the correlation between the fuel efficiency and the maximum heat release rate is not defined in a one-to-one relationship, and the target values of the performance parameters are simultaneously satisfied for all performance parameters such as NOx amount, PM amount, and fuel consumption. For example, a combination of ignition timing, ignition start delay time, heat generation rate, maximum heat generation rate, and the like is defined.

  Therefore, unlike the existing technology in which the target value of the combustion parameter is set independently for each of a plurality of performance parameters, it is possible to suppress a plurality of performance parameters from interfering with each other and to avoid deterioration of controllability due to the mutual interference. it can. That is, by using the second correlation data, it is possible to improve controllability for simultaneously setting a plurality of performance parameters to target values. In the invention of claim 6, a parameter calculation expression in which a correlation between a plurality of performance parameters and a plurality of combustion parameters is expressed by an inverse model of the engine system may be used as the second correlation data.

The block diagram of an engine control apparatus regarding 1st Embodiment of this invention. (A) is a figure which shows a combustion parameter calculation formula, (b) is a figure which shows a control parameter calculation formula. The time chart for demonstrating the combustion waveform of an engine. The flowchart which shows a control command value calculation process. The block diagram of the engine control apparatus concerning 2nd Embodiment. The flowchart which shows a correlation data change process. The flowchart which shows a correlation data change process.

  Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals in the drawings, and the description of the same reference numerals is used.

(First embodiment)
The engine control apparatus according to the present embodiment is mounted on a vehicle engine (internal combustion engine), in which high pressure fuel is injected into a plurality of cylinders # 1 to # 4 to perform compression auto-ignition combustion. A diesel engine is assumed.

  FIG. 1 is a block diagram of the engine control apparatus. A plurality of types of actuators 11 are mounted on the engine 10, and the operation of these actuators 11 is controlled by an electronic control unit (ECU 20), whereby the combustion state of the engine 10 is controlled and thus the engine performance is controlled. Is done.

  Specific examples of the actuator 11 relating to the fuel system include a fuel injection valve that injects fuel to be used for combustion, and a high-pressure pump that controls the pressure of fuel supplied to the fuel injection valve. The ECU 20 controls the pressure of the injected fuel by outputting a command value of the fuel amount (control parameter) that is sucked and discharged by the high-pressure pump to the high-pressure pump. Further, the ECU 20 outputs command values of control parameters such as the fuel injection amount (injection time) by the fuel injection valve, the injection timing, and the number of multistage injections injected per combustion to the fuel injection valve. In the present embodiment, the fuel injection valve is a direct injection type in which fuel is directly injected into the engine combustion chamber.

  Specific examples of the actuator 11 relating to the intake system include an EGR valve that controls the amount of EGR that circulates a part of exhaust gas into the intake air as EGR gas, a variable supercharger that variably controls the supercharging pressure, and fresh air into the cylinder Examples include a throttle valve that controls the inflow amount, a valve control mechanism that variably controls the opening / closing timing and lift amount of the intake valve or exhaust valve. The ECU 20 sends command values for commanding control parameters such as EGR amount, supercharging pressure, fresh air inflow amount, engine valve opening / closing timing, and lift amount to each of the EGR valve, variable supercharger, throttle valve, and valve control mechanism. Output to. As described above, the actuator 11 is operated based on the various command values output from the ECU 20, whereby the engine combustion state is controlled, and thus the engine performance is controlled.

  "Engine combustion state" is represented by a plurality of combustion parameters. Specific examples of these combustion parameters include ignition timing, ignition start delay time (time from the start of fuel injection to ignition), Heat generation rate, maximum time of heat generation rate, etc. are mentioned. These combustion parameters (ignition timing, ignition start delay time, heat generation rate, heat generation rate maximum timing) are physical quantities that can be detected by an output signal of the in-cylinder pressure sensor, for example.

  “Engine performance” is represented by a plurality of performance parameters. Specific examples of these performance parameters include physical quantities related to exhaust emissions (eg, NOx quantity, PM quantity, CO quantity, HC quantity, etc.), and output torque. Physical quantity (for example, engine output shaft rotation torque, engine speed, etc.), fuel consumption physical quantity (for example, travel distance per consumed fuel volume, fuel consumption per operating time, etc., measured by mode tests, etc.) And physical quantities related to combustion noise (for example, engine vibration, engine noise, etc.).

  The ECU 20 includes a microcomputer. The microcomputer includes a CPU for performing various calculations, a RAM as a main memory for temporarily storing data and calculation results during the calculation, a ROM as a program memory, and a data storage memory. As described above, an EEPROM (Electrically Erasable Programmable Read-Only Memory), a backup RAM (a memory that is constantly powered by a backup power source such as an in-vehicle battery after the main power of the ECU 20 is stopped), and the like are included.

  In addition, detection values of various sensors 12 and 13 mounted on the engine 10 are input to the ECU 20. The engine output sensor 12 is a sensor that detects an actual value of the performance parameter described above. For example, a sensor that detects a specific component amount (NOx amount, etc.) in exhaust, a sensor that detects torque, and a combustion sound. A sensor etc. are mentioned.

  The combustion state quantity sensor 13 is a sensor that detects the actual value of the above-described combustion parameter. For example, an in-cylinder pressure sensor that detects the pressure in the combustion chamber (in-cylinder), an ion sensor that detects the amount of ions generated due to combustion. Etc. For example, based on the change in the in-cylinder pressure detected by the in-cylinder pressure sensor, the ignition timing, the ignition start delay time, and the like can be acquired.

  The ECU 20 includes a performance parameter calculation unit 31 (performance target setting means) that calculates target values for a plurality of performance parameters as a configuration of basic functions related to engine control, and what kind of combustion to set the actual performance parameters to the target values. A combustion parameter calculation unit 32 (combustion target setting means) that calculates whether the state (combustion parameter) should be set, and an actuator control unit 33 that controls the operation (control parameter) of the actuator 11 so as to achieve the target combustion state. (Control command value calculating means), a performance parameter deviation calculating section 34 (performance feedback means) for calculating a deviation between the target value of the performance parameter and the actual value (detected value of the engine output sensor 12), and the target value of the combustion parameter Parameter deviation calculation for calculating a deviation between the actual value (detected value of the combustion state quantity sensor 13) 35 (combustion feedback means), and a. Each of these functional blocks 31 to 35 is realized by a microcomputer control program.

  The combustion parameter calculation unit 32 includes an integrator 32 a that adds the performance parameter deviation calculated by the performance parameter deviation calculation unit 34, and “second correlation data” stored in a memory (storage unit) such as a ROM of the ECU 20. And a combustion parameter calculation expression 32b.

  The combustion parameter calculation expression 32b defines the correlation between a plurality of performance parameters and a plurality of combustion parameters, and is defined by, for example, the model shown in FIG. 1 or the determinant shown in FIG. This is because “what kind of combustion state (combustion parameter) will result in what kind of engine performance (performance parameter)”, in other words “how to make the required performance parameter the combustion state It can be said that this is an arithmetic expression that defines “it is good”. Therefore, by substituting the performance parameter target value (or performance parameter change amount) into the combustion parameter calculation expression 32b, the combustion parameter target value (or combustion parameter change amount) can be obtained.

  In the present embodiment, the combustion parameter calculation expression 32b includes a plurality of products of an r-dimensional column vector A1 having a plurality of performance parameter changes as variables and a matrix A2 representing q rows and r columns of coefficients a11 to aqr. This is expressed as a q-dimensional column vector A3 with the amount of change in the combustion parameter as a variable. In the system shown in FIG. 1, the integral value of the deviation of the performance parameter is used as a plurality of performance parameter change amounts, and the integral value of the deviation is substituted into each variable constituting the column vector A1, thereby obtaining the column vector. As a solution for each variable constituting A3, the amount of change from the current value is calculated for a plurality of combustion parameters.

  In addition, by integrating the deviation by the integrator 32a and substituting the integrated value into the combustion parameter calculation formula 32b, it is possible to suppress the occurrence of steady deviation such that the actual value of the performance parameter is constantly deviated from the target value. I am trying. When the deviation integrated value calculated by the integrator 32a becomes zero, the value (change amount of the target value) calculated by the combustion parameter calculation expression 32b becomes zero, and the target value of the combustion parameter maintains the current combustion state. It will be calculated to be a value to be made.

  The actuator control unit 33 adds the combustion parameter deviation calculated by the combustion parameter deviation calculation unit 35 and “first correlation data” stored in a memory (storage means) such as a ROM of the ECU 20. And a control parameter calculation formula 33b.

  The control parameter calculation expression 33b defines the correlation between a plurality of combustion parameters and a plurality of control parameters, and is defined by, for example, the model shown in FIG. 1 or the determinant shown in FIG. This is because "what kind of control parameter is used and what kind of combustion state (combustion parameter) will be obtained", in other words, "how should the control parameter be set to achieve the target combustion state"? It can be said that it is a defined arithmetic expression. Therefore, if the target value of the combustion parameter (or the amount of change in the combustion parameter) is substituted into the control parameter calculation expression 33b, the command value of the control parameter (or the amount of change in the control parameter) can be obtained.

  In the present embodiment, the control parameter arithmetic expression 33b is obtained by multiplying a product of a q-dimensional column vector A4 having a plurality of combustion parameter changes as variables and a matrix A5 representing the coefficients b11 to bpq of p rows and q columns. This is represented as a p-dimensional column vector A6 with the change amount of the control parameter as a variable. In the system shown in FIG. 1, the integral value of the deviation of the combustion parameter is used as a plurality of variation amounts of the combustion parameter, and the integral value of the deviation is substituted into each variable constituting the column vector A4. As a solution for each variable constituting A6, a change amount from a current value is calculated for a plurality of control parameters.

  It should be noted that by integrating the deviation by the integrator 33a and substituting the integrated value into the control parameter calculation formula 33b, it is possible to suppress the occurrence of steady deviation such that the actual value of the combustion parameter is constantly deviated from the target value. I am trying. When the deviation integrated value calculated by the integrator 33a becomes zero, the value (control parameter change amount) calculated by the control parameter calculation expression 33b becomes zero, and the command value of the control parameter maintains the current command value. It will be calculated to be a value to be made.

  By the way, among the plurality of combustion parameters, for example, regarding the heat generation rate and the in-cylinder pressure indicating the heat generation state accompanying combustion in the combustion chamber, the heat generation rate is time-series data that changes in time series. The heat generation rate will be specifically described with reference to FIG. In FIG. 3, it is assumed that two-stage fuel injection (pilot injection + main injection) is performed as shown in FIG. 3 (a), and the in-cylinder pressure P accompanying the combustion of the injected fuel, the in-cylinder pressure differential value dP / dθ, The transition of the heat generation rate dQ / dθ and the heat generation rate integrated value Q is shown. The in-cylinder pressure differential value dP / dθ corresponds to the in-cylinder pressure change rate, and the heat generation rate integral value Q corresponds to the heat generation amount. The crank angle = 0 in the figure is the compression top dead center.

  Specifically, in FIG. 3, when the first-stage injection (pilot injection) is performed at timing t1, the cylinder pressure P and the cylinder pressure differential value dP / dθ are associated with the start of combustion in the combustion chamber at timing t2. Rises as shown. Such changes in the in-cylinder pressure P and the in-cylinder pressure differential value dP / dθ can be acquired based on, for example, a detection signal of the in-cylinder pressure sensor. The heat generation rate dQ / dθ rises and changes with a waveform that is substantially the same as the in-cylinder pressure differential value dP / dθ, and a combustion waveform due to the first-stage injection is observed in the period from timing t2 to t4. Timing t3 is a timing at which heat generation by the first stage combustion becomes maximum (peak value). The heat generation rate dQ / dθ can be calculated from the in-cylinder pressure differential value dP / dθ and the combustion chamber volume change rate dV / dθ.

  When the second-stage injection (main injection) is performed at timing t5, after that, at timing t6, the in-cylinder pressure P and the in-cylinder pressure differential value dP / dθ are again shown in the drawing as combustion starts in the combustion chamber. To rise. The heat generation rate dQ / dθ rises and changes with a waveform that is substantially the same as the in-cylinder pressure differential value dP / dθ, and a combustion waveform due to the second-stage injection is observed in the period from timing t6 to t8. Timing t7 is a timing at which heat generation by the second stage combustion becomes maximum (peak value). The heat generation rate integrated value Q is calculated by integrating the heat generation rate dQ / dθ, and the integrated value in one combustion stroke corresponds to the heat generation amount for each combustion.

  Here, when the fuel injection valve varies in injection characteristics due to individual differences or changes over time, the in-cylinder pressure and the heat generation rate change. That is, for example, if the nozzle hole diameter becomes small due to deposits (deposits) adhering to the nozzle hole part of the fuel injection valve, and the actual fuel injection amount decreases unintentionally, the inclination of the increase in the in-cylinder pressure is caused accordingly. Get smaller. Therefore, the amount of increase in the in-cylinder pressure differential value dP / dθ and the heat generation rate dQ / dθ (the amount of increase at timings t2 to t4 and t6 to t8) is reduced. In addition, regarding each of the injections before and after, the situation of the influence of the post-injection on the combustion caused by the combustion of the pre-injection changes, and this causes heat generation with respect to, for example, the heat generation rate dQ / dθ of the post-injection. The start timing (t6 in the figure), the peak arrival timing (t7 in the figure), and the heat generation end timing (t8 in the figure) vary.

  On the other hand, when the actual fuel injection amount increases unintentionally, the inclination of the increase in the in-cylinder pressure increases accordingly. Therefore, the amount of increase in the in-cylinder pressure differential value dP / dθ and the heat generation rate dQ / dθ (the amount of increase at timings t2 to t4 and t6 to t8) increases. Further, regarding the heat generation rate dQ / dθ of the post-injection, the heat generation start timing (t6 in the figure), the peak value arrival timing (t7 in the figure), and the heat generation end timing (t8 in the figure) vary.

  In short, the change waveform (combustion waveform) of the in-cylinder pressure and heat generation rate is different from the reference waveform, and the in-cylinder pressure and heat generation rate at a predetermined time determined according to the timing of ignition timing, etc. It is conceivable that the timing of changes in the in-cylinder pressure and the heat generation rate shift back and forth.

  Therefore, in the present embodiment, among the plurality of combustion parameters, the “heat generation rate” is determined as a specific parameter that changes in time series with the occurrence of combustion in the engine combustion chamber, and the heat generation rates are determined in advance. Time series data at time series points are included in the combustion parameters.

A plurality of time series data will be described. The plurality of time-series data are selected as representative point data representing each combustion state (combustion waveform). In the heat generation rate waveform shown in FIG. 3, the pilot that is combustion by the first stage injection is selected. Time series data is determined for each of the combustion and the main combustion that is combustion by the second stage injection. In particular,
The heat generation rate at the heat generation start timing of pilot combustion is “first data P1”,
The heat generation rate at the heat generation peak timing of pilot combustion is “second data P2”,
The heat generation rate at the end of heat generation of pilot combustion is “third data P3”,
The heat generation rate at the heat generation start timing of the main combustion is “fourth data P4”,
The heat generation rate at the heat generation peak timing of the main combustion is “fifth data P5”,
The heat generation rate at the heat generation end timing of the main combustion is “sixth data P6”,
The data P1 to P6 are included in a plurality of combustion parameters as “time series data”.

  When the respective data P1 to P6 are determined as described above, each timing of heat generation start / heat generation peak / heat generation end for pilot combustion, and heat generation start / heat generation peak / heat generation end for main combustion The timing corresponds to a plurality of predetermined time series points. For each of these time series points, a predetermined crank angle position (NE pulse number or ° CA) is determined in advance as a measurement point of each data P1 to P6, and the heat generation rate at the predetermined crank angle position is determined as each data P1 to P1. P6. Or each time series point shall find each timing of heat generation start / heat generation peak / heat generation end sequentially from the change of the heat generation rate, and the heat generation rate at each timing is also used as each data P1 to P6. Good.

  In this case, the combustion parameter calculation formula 32b shown in FIG. 2A defines a correlation between a plurality of performance parameters and a plurality of combustion parameters including time series data at each time series point. That is, the column vector A3 having the change amounts of the plurality of combustion parameters as variables includes data P1 to P6 that are time series data of the heat release rate. Further, the control parameter calculation formula 33b shown in FIG. 2B defines the correlation between a plurality of combustion parameters including time series data at each time series point and a plurality of control parameters. That is, the column vector A4 having the change amounts of the plurality of combustion parameters as variables includes data P1 to P6 which are time series data of the heat generation rate.

  In the ECU 20, the combustion parameter calculation unit 32 uses a combustion parameter calculation expression 32 b in which the change amounts of the plurality of combustion parameters including the respective time series data (P 1 to P 6) are output side column vectors A 3. Calculate the target value of the combustion parameter. Further, in the actuator control unit 33, by using a control parameter calculation expression 33b in which the change amounts of the plurality of combustion parameters including the respective time series data (P1 to P6) are the input side column vector A4, Calculate the command value.

  Next, a procedure (control command value calculation process) for calculating the command value of the control parameter output to the actuator 11 as described above will be described with reference to the flowchart of FIG. The control command value calculation process is repeatedly executed by the microcomputer of the ECU 20 at a predetermined cycle (for example, the calculation cycle performed by the CPU described above or every predetermined crank angle).

  First, in step S11, a target value is calculated for each of a plurality of performance parameters based on the engine operating state such as the engine speed and the accelerator operation amount (load) by the driver. This process corresponds to the process executed by the performance parameter calculation unit 31. For example, a map in which optimum values of performance parameters for engine rotation speed and accelerator operation amount are stored in advance by a conformance test, and the target performance parameters may be calculated using the map.

  In the subsequent step S12, actual values of a plurality of performance parameters are acquired based on the detected values of the engine output sensor 12. Note that the actual value of the performance parameter may be acquired by estimation using a calculation means such as a model. In particular, for a performance parameter for which the engine output sensor 12 is not provided among a plurality of performance parameters, it is effective to substitute the estimated value as an actual value of the performance parameter.

  In subsequent step S13, a deviation (performance parameter deviation) between the target value of each performance parameter calculated in step S11 and the actual value of each performance parameter acquired in step S12 is calculated. This process corresponds to the process executed by the performance parameter deviation calculating unit 34.

  In subsequent step S14, an integral value x (i) of each deviation calculated in step S13 is calculated. Specifically, the current integration value x (i) for each of the plurality of performance parameters is calculated by adding the current performance parameter deviation to the previous integration value x (i−1). This process corresponds to the process executed by the integrator 32a.

  In subsequent step S15, a target value is calculated for each of the plurality of combustion parameters. Specifically, the deviation integrated value x (i) calculated in step S13 is substituted into the combustion parameter calculation expression 32b, and a solution obtained by the substitution is represented by a plurality of combustion parameter change amounts (change amounts from current values). ). Also, based on engine operating conditions such as engine speed and load, the combustion parameter reference value is calculated by, for example, a map or mathematical formula, and the combustion parameter change amount is added to the reference value, and the sum is added to the new combustion The target value of the parameter is set (combustion parameter target value = reference value + combustion parameter change amount).

  In the subsequent step S16, actual values of a plurality of combustion parameters are acquired based on the detected values of the combustion state quantity sensor 13. In addition, you may make it acquire the actual value of a combustion parameter by estimation using calculation means, such as a model. In particular, for parameters for which the combustion state quantity sensor 13 is not provided among a plurality of combustion parameters, it is effective to substitute the estimated value as the actual value of the combustion parameter.

  In subsequent step S17, a deviation (combustion parameter deviation) between the target value of each combustion parameter calculated in step S15 and the actual value of each combustion parameter acquired in step S16 is calculated. This process corresponds to the process executed by the combustion parameter deviation calculation unit 35.

  In the subsequent step S18, an integral value y (i) of each deviation calculated in step S17 is calculated. Specifically, the current integration value y (i) for each of the plurality of combustion parameters is calculated by adding the current combustion parameter deviation to the previous integration value y (i-1). This process corresponds to the process executed by the integrator 33a.

  At this time, as described above, the plurality of combustion parameters include data P1 to P6 which are time series data of the heat release rate, and the calculation of target values (step S15) and actual values for each of these data P1 to P6 is also performed. Value acquisition (step S16), deviation calculation (step S17), and deviation integration (step S18) are sequentially performed. In the actual value acquisition (step S16), each data P1 to P6 is based on the detection value of the in-cylinder pressure sensor at a predetermined crank angle position set in advance as the detection position of each data P1 to P6. The actual value of is obtained.

  If there are individual differences or changes over time in the fuel injection valve (clogging of injection holes due to deposits, etc.), heat generation at pilot combustion and main combustion at the heat generation start timing, heat generation peak timing, and heat generation end timing The rate deviates from the target value obtained from each performance parameter, and the deviation is calculated as an integral value y (i).

  In subsequent step S19, a command value (control parameter command value) is calculated for each of the plurality of control parameters. Specifically, the integrated value y (i) of the deviation calculated in step S18 is substituted into the control parameter calculation expression 33b, and the solution obtained by the substitution is used as a change amount of a plurality of control parameters (change amount from the current value). Calculate as Further, based on the engine operating conditions such as engine rotation speed and load, for example, a reference command value of the control parameter is calculated by a map or a mathematical formula, the amount of change of the control parameter is added to the reference command value, and the sum is A new control parameter command value is set (control parameter command value = reference command value + change amount of control parameter). This control parameter command value is the actuator control amount that is finally output to the various actuators 11.

  According to the embodiment described in detail above, the following excellent effects can be obtained.

  In the present embodiment, when calculating the command value of each control parameter, the control parameter calculation formula 33b as the first correlation data is used, and the controllability for simultaneously setting a plurality of combustion parameters to the target value is improved. be able to. Further, in calculating the target value of each combustion parameter, the combustion parameter calculation formula 32b as the second correlation data is used, and controllability for simultaneously setting a plurality of performance parameters to the target value can be improved. . In addition, a plurality of performance parameters and a plurality of combustion parameters can be coordinated. As described above, the engine performance can be suitably controlled.

  Further, the plurality of combustion parameters are specific parameters that change in time series with the occurrence of combustion, and include the time series data that is data at a plurality of time series points for the specific parameters. However, since the correlation between the time series data and the control parameter at each time series point is defined, the command value of the control parameter is calculated by taking into account the time series characteristics (combustion waveform) for each combustion parameter. As a result, even if there is a difference in the waveform of the in-cylinder pressure or the heat generation rate due to individual differences in fuel injection valves or changes over time, the engine performance can be controlled while reflecting them.

  As described above, it is possible to appropriately control the engine performance by improving the controllability of the combustion state of the engine, and it is possible to realize suitable control reflecting the individual difference and the change with time in the actuator 11.

  The time series data of the heat generation rate as the specific parameter includes the heat generation rate at each timing of heat generation start / heat generation peak / heat generation end for each of the pilot combustion and the main combustion. In this case, the heat generation rate at each timing is physically meaningful in grasping the combustion characteristics, and reflects the influence of individual differences of actuators 11 and changes with time. Therefore, when the performance parameter is controlled in consideration of the combustion state, individual differences of the actuator 11 and changes with time can be favorably reflected.

  Further, the feedback control is performed so that the actual value of the performance parameter matches the target value, and the feedback control is performed so that the actual value of the combustion parameter matches the target value. Thereby, the robustness with respect to the change of environmental conditions can also be improved. For example, even if a change in actual value occurs due to environmental conditions such as engine water temperature, it can be made to follow the target value.

(Second Embodiment)
In the first embodiment, “a plurality of performance parameter deviations” are substituted into the combustion parameter calculation formula 32b as the second correlation data, and “amount of change in the plurality of combustion parameters” is calculated as the solution, and the first correlation is calculated. Although “a plurality of combustion parameter deviations” are substituted into the control parameter calculation formula 33b as data and “amount of change of a plurality of control parameters” is calculated as a solution (see FIG. 1), this is changed.

  That is, in this embodiment, as shown in FIG. 5, “target values of a plurality of performance parameters” are substituted into the combustion parameter calculation expression 32b as the second correlation data, and “target values of a plurality of combustion parameters” are obtained as a solution. Is calculated, and “target values of a plurality of combustion parameters” is substituted into the control parameter calculation expression 33b as the first correlation data, and “command values of a plurality of control parameters” are calculated as a solution.

  Further, in FIG. 5, a feedback control unit 51 and a correction unit 52 are provided for calculating the target value of the combustion parameter, and the target values of a plurality of performance parameters calculated by the combustion parameter calculation formula 32 b are used as the feedback control unit 51. The correction is performed using the feedback correction amount calculated in (1). Further, regarding the calculation of the control parameter command value, a feedback control unit 53 and a correction unit 54 are provided, and the feedback control unit 53 calculates the command values of a plurality of control parameters calculated by the control parameter arithmetic expression 33b. The correction is made according to the correction amount.

  Also in the present embodiment, the same cooperative control (correlation control based on correlation data) as in the first embodiment is performed, and the actual values of the combustion parameter and the performance parameter are fed back, so the same as in the first embodiment. The effect is demonstrated. In addition, by including time-series data for a plurality of combustion parameters as described above, it is possible to calculate command values for control parameters by taking into account time-series characteristics (combustion waveforms) for each combustion parameter, and controlling engine performance. Can be improved.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be implemented as follows, for example.

  -Time series point setting means for variably setting the number of time series points in the time series data based on the operating state of the engine, and correlation data (combustion parameter calculation based on the number of time series points set in the time series data Part or all of the expression 32b and the control parameter calculation expression 33b) may be changed. FIG. 6 is a flowchart showing the correlation data changing process, and this process is performed by the ECU 20 at a predetermined cycle.

  In FIG. 6, in step S21, the engine rotation speed and the load (for example, accelerator opening) are detected as the current engine operating state. In the subsequent step S22, the number of time series points of the time series data is set based on the current engine operating state. Specifically, in a low load state such as an idle state, it is considered that the degree of influence due to individual differences of the actuators 11 and changes over time is greater than in a high load state where the load is higher than that. The more the time series points are increased. Alternatively, among the predetermined low rotation range and the high rotation range on the higher rotation side, the time series score is increased in the low rotation range than in the high rotation range. It is also possible to set the number of time series points by simultaneously considering the load condition and the rotation speed condition.

  Thereafter, in step S23, the correlation data (combustion parameter calculation formula 32b, control parameter calculation formula 33b) to be used this time is selected based on the number of time series points each time. In this embodiment, as the combustion parameter calculation formula 32b and the control parameter calculation formula 33b, a plurality of calculation formulas each having a different number of combustion parameters are prepared in advance, and one of them is selected. For example, in a low load state such as an idle state, the number of time series points is set to “6”, and an arithmetic expression including each of the above data P1 to P6 (see FIG. 3) as a combustion parameter is used. An arithmetic expression including data P1, P2, P4, and P5 (see FIG. 3) as combustion parameters with the number of series points being “4”, or data P2, P5 (see FIG. 3) with the number of time series points being “2” Is used as a combustion parameter. In the low rotation range, the number of time series points is set to “6”, and an arithmetic expression including each of the data P1 to P6 (see FIG. 3) as a combustion parameter is used. An arithmetic expression including data P1, P2, P4 and P5 (see FIG. 3) as combustion parameters with the number “4”, or data P2, P5 (see FIG. 3) with the number of time series points as “2” as the combustion parameters An arithmetic expression included as follows is used. Each arithmetic expression may be changed in part, for example, by increasing or decreasing the number of data in the time-series data portion (the number of data in the column vector) in addition to all being changed.

  The arithmetic expressions set in this way are used in step S15 and step S19 in the control command value calculation process of FIG.

  In short, if the engine operating state is different, it is considered that the degree of influence due to the individual difference of the actuator 11 and the change over time is different, but in the above configuration, the number of time series points of the time series data based on the engine operating state. Therefore, the engine performance can be controlled while taking into account the individual differences of the actuators 11 and the degree of influence due to changes over time.

  Also, when variably setting the number of time series points in the time series data based on the engine rotation speed, the time series points are increased in the low rotation range than in the high rotation range, so the engine rotation speed is small, It is possible to improve the control accuracy of the engine performance under a situation in which the degree of influence due to individual differences of the actuators 11 and changes with time tends to increase. This can be said to be advantageous even if the calculation load on the ECU 20 is taken into consideration, that is, a configuration that increases the time series score in the low rotation range (in other words, a configuration that decreases the time series score in the high rotation range).

  The ECU 20 is configured to be able to variably set the injection mode of the fuel injection valve based on the engine operating state (engine speed, load, etc.). Specifically, there are an injection mode in which one fuel injection is performed for one combustion and an injection mode in which multiple fuel injections are performed as a plurality of injection modes. Further, in the case of performing a plurality of fuel injections, for example, the number of times each injection divided into pilot injection, main injection, after-injection, etc., may be changed each time. Then, a part or all of the correlation data (combustion parameter calculation formula 32b, control parameter calculation formula 33b) is changed based on each injection mode. FIG. 7 is a flowchart showing the correlation data changing process, and this process is performed by the ECU 20 at a predetermined cycle.

  In FIG. 7, in step S31, the engine rotation speed and the load (for example, accelerator opening) are detected as the current engine operating state. In the subsequent step S32, the injection mode is set based on the current engine operating state. For example, pilot (2 times) + main injection mode is used in the low load / low rotation range, pilot + main + after injection mode is used in the medium load / medium rotation range, and only main is used in the high load / high rotation range. The injection mode is as follows.

  Thereafter, in step S33, correlation data (combustion parameter calculation formula 32b, control parameter calculation formula 33b) to be used this time is selected based on the injection mode. In this embodiment, as the combustion parameter calculation formula 32b and the control parameter calculation formula 33b, a plurality of calculation formulas each having a different number of combustion parameters are prepared in advance, and one of them is selected. In this case, the number of time series points is determined according to the number of injections, the injection interval, and the injection content, and an arithmetic expression including time series data matching the number of time series points as a combustion parameter is selected.

  The arithmetic expressions set in this way are used in step S15 and step S19 in the control command value calculation process of FIG.

  In short, when the injection mode of the fuel injection valve is different, the time-series data (combustion waveform) regarding combustion is also different. In this regard, in the above configuration, since at least a part of the correlation data is changed in accordance with the injection mode of the fuel injection valve, the engine performance is controlled while taking into account the change of the time series data accompanying the change of the injection mode. it can. It is also possible to combine the processing of FIG. 6 and the processing of FIG. 7, for example, in principle, correlation data (each arithmetic expression) is determined based on the injection mode, and then the engine operating state is taken into account. It is possible to do so.

  In each of the above embodiments, as the configuration for calculating the target values of the plurality of combustion parameters, correlation data defining the correlation between the plurality of performance parameters and the plurality of combustion parameters (combustion parameter calculation formula 32b as second correlation data) However, this configuration may be changed. For example, instead of the combustion parameter calculation formula 32b as the second correlation data, a predetermined conformity map or the like is used, and target values of a plurality of combustion parameters are set based on the engine operating state (for example, engine speed, load, etc.). It is good also as a structure to set.

  For the waveform (combustion waveform) of in-cylinder pressure and heat generation rate during combustion, each timing (each crank angle position ° CA) that can be grasped as heat generation start, heat generation peak, and heat generation end is set as time series data. The target value of the combustion parameter and the command value of the control parameter may be calculated using correlation data (combustion parameter calculation formula 32b, control parameter calculation formula 33b) including the time series data in a plurality of combustion parameters. .

  In the above embodiment, the heat generation rate is exemplified as the specific parameter of the combustion parameter including the time series data, but instead of this, among the in-cylinder pressure, the in-cylinder pressure differential value, the heat generation rate integral value, and the in-cylinder temperature. Any one of them may be used as a specific parameter. In this case, in the control parameter calculation formula 33b as the first correlation data and the combustion parameter calculation formula 32b as the second correlation data, the in-cylinder pressure, the in-cylinder pressure differential value, the heat release rate integral value, the in-cylinder Any time-series data of temperature will be included.

  In each of the above embodiments, the feedback control of the combustion parameter and the performance parameter is performed. However, in implementing the present invention, at least one of these feedback controls may be abolished and open control may be performed. Specifically, in the block diagram shown in FIG. 5, the performance parameter deviation calculating unit 34, the feedback control unit 51, and the correcting unit 52 are abolished, and target values of a plurality of combustion parameters calculated by the combustion parameter calculation formula 32b are obtained. You may output to the actuator control part 33, without performing a feedback calculation. Further, the combustion parameter deviation calculation unit 35, the feedback control unit 53, and the correction unit 54 are abolished, and command values of a plurality of control parameters calculated by the control parameter calculation formula 33b are output to each actuator 11 without performing feedback calculation. May be.

  In a multi-cylinder engine, it is conceivable that individual differences in actuators and changes over time occur for each cylinder, for example, variation in injection characteristics of the fuel injection valve differs for each cylinder. Therefore, it may be configured such that the performance parameter deviation or the combustion parameter deviation is calculated for each cylinder, and as a result, engine control is performed for each cylinder.

  In each of the above embodiments, when calculating the target value of the combustion parameter, the second correlation data (combustion parameter calculation formula 32b) defining the correlation between the plurality of performance parameters and the plurality of combustion parameters is used, and the command value of the control parameter Is calculated using the first correlation data (control parameter calculation expression 33b) that defines the correlation between the plurality of combustion parameters and the plurality of control parameters. Of these, regarding the calculation of the target value of the combustion parameter, It is good also as a structure which uses a conformity map, without using 2 correlation data (combustion parameter calculation formula 32b).

  Moreover, the structure which memorize | stores 1st correlation data and 2nd correlation data in the form which is not a parameter computing equation (determinant) may be sufficient. For example, the configuration may be such that each of these correlation data is stored in a map format. In this case, with regard to the second correlation data, for each combustion parameter included in the “plurality of combustion parameters”, a constant value representing a correlation with the plurality of control parameters may be stored in a map format. Regarding the first correlation data, for each control parameter included in the “plurality of control parameters”, a constant value representing a correlation with the plurality of combustion parameters may be stored in a map format.

  DESCRIPTION OF SYMBOLS 10 ... Engine, 11 ... Actuator, 20 ... ECU (time series point setting means), 31 ... Performance parameter calculation part (performance target setting means), 32 ... Combustion parameter calculation part (combustion target setting means), 32b ... Combustion parameter calculation Expression (second correlation data), 33 ... Actuator control section (control command value calculation means), 33b ... Control parameter calculation formula (first correlation data), 34 ... Performance parameter deviation calculation section, 35 ... Combustion parameter deviation calculation section.

Claims (6)

An engine control device that controls the combustion state of an engine by controlling the operation of an actuator,
Combustion target setting means for setting a target value of each combustion parameter for a plurality of combustion parameters representing the combustion state;
Using the first correlation data defining the correlation between the plurality of combustion parameters and the control parameters related to the actuator, the command value of the control parameter is calculated based on the target value of each combustion parameter set by the combustion target setting means. Control command value calculating means;
With
The plurality of combustion parameters are specific parameters that change in time series with the occurrence of combustion in the engine combustion chamber, and include time-series data that is data at a plurality of time-series points predetermined for the specific parameters. The first correlation data defines the correlation between the time series data at each time series point and the control parameter,
The combustion target setting means sets a target value of time series data at each time series point,
The engine control device, wherein the control command value calculating means calculates the command value of the control parameter based on a target value of time series data at each time series point using the first correlation data. Time-series point setting means for variably setting the number of time-series points of the time-series data based on the operating state of the engine;
The engine control device according to claim 1, further comprising: means for changing at least a part of the first correlation data based on a set number of time series points of the time series data.   The time series point setting means is configured to variably set the number of time series points of the time series data based on the engine rotation speed, and a predetermined low rotation range and a high rotation range higher than that 3. The engine control device according to claim 2, wherein the time series score is increased in the low rotation range than in the high rotation range. The actuator is a fuel injection valve that injects fuel to the engine, and an engine control device that can variably set an injection mode at the time of fuel injection by the fuel injection valve,
The engine control device according to any one of claims 1 to 3, further comprising means for changing at least a part of the first correlation data based on the set injection mode.   The specific parameter is combustion waveform data of at least one of in-cylinder pressure, in-cylinder pressure change rate, heat generation rate, and heat generation amount in the engine combustion chamber, and combustion of fuel injected from a fuel injection valve as the actuator The combustion waveform data at the start timing, the combustion waveform data at the combustion peak, and the combustion waveform data at the combustion end timing are included as time series data at least at each time series point. 5. The engine control device according to any one of 4. Performance target setting means for setting a target value of each performance parameter for a plurality of performance parameters representing engine performance,
The combustion target setting means uses second correlation data defining correlations between the plurality of performance parameters and the plurality of combustion parameters, and based on the target values of the performance parameters set by the performance target setting means. The engine control apparatus according to any one of claims 1 to 5, wherein target values of the plurality of combustion parameters for each target value are calculated.

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