JP5742684B2 - Engine predictive control device - Google Patents

Description

  The present invention relates to an engine predictive control device, and more particularly to an engine predictive control device that predicts an in-cylinder air amount that will be achieved in the future from a target throttle opening by executing a delay control of a throttle.

  In an engine equipped with an electronically controlled throttle, the target throttle opening is determined based on the accelerator opening of the driver, and the throttle is operated according to the target throttle opening. At this time, instead of operating the throttle immediately according to the determined target throttle opening, the change in the actual throttle opening can be delayed with respect to the change in the target throttle opening. Such arithmetic processing is called throttle delay control. If delay control is performed, the actual throttle opening changes with the delay time with respect to the change in the target throttle opening, so the future throttle opening is predicted from the target throttle opening by the delay time. can do. If the future throttle opening can be predicted, the in-cylinder air amount (or in-cylinder charging efficiency) at the prediction time can be predicted from the throttle opening. The predicted in-cylinder air amount can be used for calculation of the fuel injection amount necessary for realizing the target air-fuel ratio.

  However, there is a problem with the conventional delay control. In the conventional delay control, the delay time is set to a constant value, for example, 32 msec. In FIG. 7, the change with time of the target throttle opening is drawn with a solid line, and the change with time of the actual throttle opening is drawn with a dotted line. The left chart in FIG. 7 shows the relationship between the target throttle opening and the actual throttle opening during sudden acceleration, and the right chart shows the relationship between the target throttle opening and the actual throttle opening during slow acceleration. . As can be seen from the comparison of the two charts, when the delay time is constant, the throttle response becomes low at the time of sudden acceleration compared to that at the time of slow acceleration.

  As a solution to such a problem, for example, it is conceivable to make the delay time variable. However, in this case, a process for selecting the optimal delay time is required, and a process for changing the delay time is also required. Further, the in-cylinder air amount is predicted based on the changed delay time. Processing is also required. In a single-core system generally used in the past, it is difficult to execute all these processes without delay.

  One possible solution is the utilization of a multi-core system having a plurality of cores. The use of a multi-core system in an engine control device is a known idea as described in, for example, Japanese Patent Application Laid-Open No. 2010-12612.

JP 2010-126121

  However, regarding the execution of delay control for predicting calculation of the in-cylinder air amount in a multi-core system and its specific method, it is described or suggested in any prior art documents including Japanese Patent Application Laid-Open No. 2010-126022. It has not been.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an engine predictive control apparatus in which a delay time is made variable by adopting a multi-core system.

  In order to achieve the above object, the first invention implements delay control for delaying the change in the actual throttle opening with respect to the change in the target throttle opening calculated from the accelerator opening, and is achieved in the cylinder in the future. In the engine predictive control device that predicts the air amount from the target throttle opening, the predictive control device has a plurality of cores each set with a different prediction time, and each of the plurality of cores is set. When the delay control is performed using the predicted time as a delay time, a predicted in-cylinder air amount that will be achieved in the future by the set predicted time is calculated based on the target throttle opening, Select one of the predicted in-cylinder air amounts calculated by each of the plurality of cores, and give the selected predicted in-cylinder air amount. Is characterized by carrying out said delay control the estimated time that is set in the delay time.

  According to a second aspect of the present invention, in the engine predictive control device according to the first aspect, when the amount of change in the accelerator opening is smaller than the first threshold, the predictive control device is a part of the plurality of cores. It is characterized by stopping the core.

  According to a third aspect of the present invention, in the engine predictive control device according to the first or second aspect, the predictive control device sets the shortest predicted time when the amount of change in the accelerator opening is larger than the second threshold value. It is characterized by stopping cores other than the core that has been made.

  According to a fourth aspect of the present invention, there is provided the engine predictive control device according to any one of the first to third aspects, wherein the predictive control device has a state in which the change amount of the accelerator opening is smaller than the third threshold value for a predetermined time. In such a case, it is characterized in that cores other than the core for which the longest predicted time is set are stopped.

  According to a fifth aspect of the present invention, in the engine predictive control device according to any one of the first to fourth aspects of the invention, the predictive control device sets a shorter predicted time as the change in the target throttle opening degree is abrupt. The predicted in-cylinder air amount calculated by the core is selected.

  According to a sixth aspect of the present invention, in the engine prediction control apparatus according to any one of the first to fourth aspects, the prediction control apparatus includes one control cycle of the predicted in-cylinder air amount calculated by each of the plurality of cores. The estimated in-cylinder air amount calculated by the core with the longest prediction time is selected from the cores in which the change amount is equal to or less than a predetermined value during acceleration, and the change amount is calculated during deceleration. It is characterized in that the predicted in-cylinder air amount calculated by the core having the shortest prediction time among the cores having a predetermined value or more is selected.

  According to the first invention, since the predicted in-cylinder air amount is calculated in parallel with different prediction times for a plurality of cores, the delay time can be changed without causing a delay in the calculation of the predicted in-cylinder air amount. can do.

  According to the second invention, in a situation where the amount of change in the accelerator opening is small and high response to the throttle is not required, useless power consumption can be suppressed by stopping some of the plurality of cores. Can do.

  On the other hand, if the amount of change in the accelerator opening is large enough to exceed a certain threshold value, it is desirable to make the delay time as short as possible so that the driver can quickly follow the throttle operation. According to the third aspect of the invention, it is possible to suppress wasteful power consumption by stopping the cores for which the shortest predicted time is set, that is, the cores other than the core that gives the shortest delay time.

  Further, if the state in which the amount of change in the accelerator opening remains small for a certain period of time, it can be determined that the vehicle is in the steady travel mode in which there is no movement of the throttle. In this case, the prediction time can be maximized. According to the fourth invention, it is possible to suppress wasteful power consumption by stopping cores other than the core for which the longest predicted time is set, that is, the core that gives the longest delay time.

  According to the fifth aspect, since the calculation by the core having a shorter predicted time is selected as the change in the target throttle opening degree becomes steeper, the transient response of the throttle is shortened by the shorter delay time. Is increased.

  According to the sixth aspect, it is possible to determine the optimum predicted time and delay time not from the accelerator opening or the target throttle opening but from the amount of change in the predicted in-cylinder air amount per control cycle.

It is a figure which shows the structure of the prediction control apparatus of the engine of embodiment of this invention. It is a figure for demonstrating the setting of the prediction time (delay time) for every core. It is a flowchart which shows the routine for selecting the prediction in-cylinder air amount to be used. It is a figure for demonstrating the example of the calculation result by the routine shown in FIG. It is a figure for demonstrating the example of the calculation result by the routine shown in FIG. It is a figure for demonstrating the effect of the prediction control apparatus of the engine of embodiment of this invention. It is a figure for demonstrating the problem in the delay control of the conventional throttle.

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

  FIG. 1 is a diagram showing the configuration of an engine predictive control apparatus according to an embodiment of the present invention. In the present embodiment, a predictive control device is realized as one function of the ECU 10 that controls the engine. The engine to be controlled by the predictive control device is a gasoline engine having an electronically controlled throttle 4. The ECU 10 serving as a predictive control device calculates a target throttle opening from the accelerator opening measured by the accelerator opening sensor 2 and delays the change in the actual opening of the throttle 4 with respect to the change in the target throttle opening. By implementing the above, the in-cylinder air amount to be achieved in the future is predicted from the target throttle opening.

  The ECU 10 of the present embodiment is configured as a multi-core system having a plurality of cores 12 and 14. In FIG. 1, the numbers assigned to the cores 12 and 14 are the numbers assigned to the respective cores. For example, # 16 means the 16th core. The ECU 10 uses a group of cores 14 of the built-in cores 12 and 14 for calculation of the predicted in-cylinder air amount. In the example shown in FIG. 1, 32 cores from # 1 to # 32 are assigned to the calculation of the predicted in-cylinder air amount. Further, the ECU 10 uses one core 12 other than the core 14 assigned for calculating the predicted in-cylinder air amount for overall control. In the example shown in FIG. 1, the # 0 core is assigned for control.

  Different predicted times are set for the cores 14 from # 1 to # 32 to which the calculation of the predicted in-cylinder air amount is assigned. Specifically, the core number assigned to each core 14 represents the predicted time set for that core. Therefore, the prediction time is set to 1 msec for the # 1 core, the prediction time is set to 16 msec for the # 16 core, and the prediction time is set to 32 msec for the # 32 core. The predicted time set for each core 14 corresponds to the delay time when the delay control of the throttle 4 is performed. In FIG. 2, the change with time of the target throttle opening is drawn with a solid line for the three cores # 1, # 16 and # 32, and the change with time of the virtual actual throttle opening calculated with these cores is shown. It is drawn with a dotted line.

  Assuming that the delay control of the throttle 4 is performed as illustrated in FIG. 2, each core 14 calculates a predicted in-cylinder air amount that will be achieved in the future for the predicted time based on the target throttle opening. An air model is used for calculation of the predicted in-cylinder air amount by each core 14. The air model is a physical model in which the relationship between the throttle opening and the in-cylinder air amount is modeled based on fluid dynamics. The calculation of the target throttle opening may be performed by each core 14, or a calculation result by a core other than that for calculating the predicted in-cylinder air amount may be used.

  The control core 12 performs the delay control of the throttle 4, the calculation control by the respective cores 14, and the fuel injection control based on the predicted in-cylinder air amount calculated by the respective cores 14. In a series of controls performed by the core 12, first, a predicted in-cylinder air amount used for calculation of the fuel injection amount is selected from the predicted in-cylinder air amount calculated by each core. When the predicted in-cylinder air amount to be used is determined, the delay control of the throttle 4 is performed using the predicted time set in the core that gives the predicted in-cylinder air amount as a delay time.

  The flowchart in FIG. 3 shows one of the routines executed by the core 12. This routine is a routine for selecting a predicted in-cylinder air amount used for calculation of the fuel injection amount. The core 12 executes this routine every control cycle. The contents of the routine shown in FIG. 3 will be described below.

  In the first step S2 of the routine shown in FIG. 3, the change amount of the accelerator opening per control cycle is calculated, and it is determined whether or not the value is equal to or greater than a predetermined threshold (first threshold) A_min. If the accelerator opening change amount is equal to or greater than the threshold value A_min, whether or not the change amount of the accelerator opening amount per control cycle is equal to or less than a predetermined threshold value (second threshold value) A_max greater than the threshold value A_min in the next step S4. Determined.

  As a result of the determination in step S2 and step S4, if it is found that the accelerator opening change amount is larger than the threshold value A_max, the process of step S8 is performed. In step S8, only the # 1 core for which the shortest predicted time is set is used for the calculation of the predicted in-cylinder air amount, and the calculation result by the # 1 core is supplied to the core 12. According to this, since the delay time is set to the shortest 1 msec, the operation of the throttle 4 can follow the driver's fast accelerator operation. Further, in this case, since all computations by the cores other than the # 1 core are stopped, there is an advantage that wasteful power consumption can be suppressed.

  As a result of the determination in step S2 and step S4, when it is found that the accelerator opening change amount is within the threshold A_min and below the threshold A_max, the process of step S10 is performed. In step S10, calculation of the predicted in-cylinder air amount is permitted for all the cores 14 from # 1 to # 32. Each core 14 calculates a future predicted in-cylinder air amount according to the set prediction time, and supplies the calculated result to the core 12.

  On the other hand, if it is found as a result of the determination in step S2 that the accelerator opening change amount is less than the threshold value A_min, the process of step S6 is performed. In step S6, computations by some of the cores 14 from # 1 to # 32 are stopped. Specifically, thinning of the core used for calculating the predicted in-cylinder air amount is performed at intervals of 4 msec. The remaining cores calculate the future predicted in-cylinder air amount in accordance with the predicted time set for each of the cores in the same manner as in step S <b> 10, and supply the calculation result to the core 12.

  When the accelerator opening change amount is smaller than the threshold A_min, the subsequent change in the throttle opening is small, and the difference in the in-cylinder air amount due to the length of the delay time is considered to be small. Therefore, even if the set number of prediction times is reduced, the accuracy does not decrease. On the other hand, a merit that wasteful power consumption can be suppressed is obtained by stopping some cores.

  After the process of step S10 or step S6, the determination of step S12 is performed. In step S12, it is determined whether or not the current value Air_Est_16ms (n) of the predicted in-cylinder air amount by the # 16 core is equal to or greater than the previous value Air_Est_16ms (n-1). The predicted time of 16 msec set for the # 16 core is an intermediate value in the distribution of predicted time from 1 msec to 32 msec. Therefore, if the current value Air_Est_16ms (n) of the predicted in-cylinder air amount obtained at the predicted time of 16 msec is greater than or equal to the previous value Air_Est_16ms (n-1), it can be determined that the engine will enter an acceleration state in the future. it can. Conversely, if the current value Air_Est_16ms (n) of the predicted in-cylinder air amount is less than the previous value Air_Est_16ms (n-1), it can be determined that the engine will enter a deceleration state in the future.

  As a result of the determination in step S12, if it is determined that the current value Air_Est_16ms (n) is equal to or greater than the previous value Air_Est_16ms (n-1), the process of step S14 is performed. In step S14, the prediction difference between the current value Air_Est_Xms (n) and the previous value Air_Est_Xms (n-1) of the predicted in-cylinder air amount is calculated for all the cores for which the predicted in-cylinder air amount has been calculated. When the engine is in an acceleration state, the predicted in-cylinder air amount increases as the predicted time increases. Further, the longer the prediction time is and the larger the predicted acceleration is, the larger the prediction difference between the current value and the previous value is.

  In step S14, cores for which the prediction difference between the current value and the previous value of the predicted in-cylinder air amount is equal to or less than a predetermined threshold are selected, and the core having the longest prediction time is selected from among the cores. . That is, the core having the maximum “X” is selected from the cores having the prediction difference equal to or less than the threshold. Then, the predicted in-cylinder air amount calculated by the selected core is selected for calculation of the fuel injection amount, and delay control is performed using the predicted time set for the core as a delay time. The reason why the threshold is provided for the prediction difference is to prevent the predicted in-cylinder air amount from changing excessively suddenly.

  4 and 5 show examples of calculation results in step S14. The upper graph of each figure shows the current value and the previous value of the predicted in-cylinder air amount Air_Est_Xms calculated for each core from # 1 to # 32. The value indicated by the white circle is the current value, and the value indicated by the black circle is the previous value. The lower graph of each figure shows the predicted difference between the current value Air_Est_Xms (n) and the previous value Air_Est_Xms (n-1) of the predicted in-cylinder air amount shown in the upper graph. A value indicated by a triangle is a predicted difference in predicted in-cylinder air amount calculated by each core. In the graph, the threshold value of the prediction difference is indicated by a dotted line.

  FIG. 4 shows a calculation result when a sudden acceleration is predicted, and FIG. 5 shows a calculation result when a slow acceleration is predicted. In the example shown in FIG. 4, the predicted difference in the predicted in-cylinder air amount calculated by the cores from # 1 to #Y is less than the threshold, and the predicted in-cylinder calculated by the cores from # Y + 1 to # 32 The predicted difference in air volume exceeds the threshold. Therefore, the predicted in-cylinder air amount calculated by the core of #Y is selected for calculating the fuel injection amount. Similarly, in the example shown in FIG. 5, the predicted in-cylinder air amount calculated by the #Z core is selected for calculating the fuel injection amount.

  As can be seen from the comparison of the two calculation result examples, according to the processing in step S14, when the sudden acceleration is predicted, the calculation by the core having a relatively short prediction time is selected, and the slow acceleration is predicted. In such a case, an operation by a core having a relatively long prediction time is selected. According to this, as schematically shown in FIG. 6, the delay time can be shortened when sudden acceleration is predicted, and the delay time can be lengthened when slow acceleration is predicted. Therefore, the greater the acceleration predicted from the change in the accelerator opening, the shorter the delay time, thereby increasing the transient response of the throttle 4.

  On the other hand, if it is found as a result of the determination in step S12 that the current value Air_Est_16ms (n) is less than the previous value Air_Est_16ms (n-1), that is, if it is found that the engine will enter a deceleration state in the future, The process of step S16 is performed. In step S16, the prediction difference between the previous value Air_Est_Xms (n-1) and the current value Air_Est_Xms (n) of the predicted in-cylinder air amount is calculated for all the cores for which the predicted in-cylinder air amount has been calculated. In step S16, the core whose prediction difference between the previous value and the current value of the predicted in-cylinder air amount is equal to or greater than a predetermined threshold is selected, and the core with the shortest prediction time is selected from the cores. That is, the core with the smallest “X” is selected from the cores with the prediction difference equal to or greater than the threshold. Then, the predicted in-cylinder air amount calculated by the selected core is selected for calculation of the fuel injection amount, and delay control is performed using the predicted time set for the core as a delay time.

  According to the processing in step S16, the delay time can be shortened when sudden deceleration is predicted, and the delay time can be lengthened when slow deceleration is predicted. Therefore, the larger the deceleration predicted from the change in the accelerator opening, the shorter the delay time, thereby increasing the transient response of the throttle 4.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, as a configuration of the predictive control device, the control core 12 is not provided separately, but each of the cores 14 for calculating the predicted in-cylinder air amount has a function of delay control or fuel injection control. Also good.

  Further, in the routine shown in FIG. 3, it is determined whether or not the state in which the change amount of the accelerator opening is smaller than a predetermined threshold (third threshold) continues for a predetermined time. A process for operating only the core may be added. This is because it can be determined that the vehicle is in the steady travel mode in which there is no movement of the throttle when the amount of change in the accelerator opening is small for a certain period of time. By stopping cores other than the # 32 core that gives the longest delay time, wasteful power consumption can be suppressed.

2 Accelerator opening sensor 4 Electronically controlled throttle 10 ECU
12 cores (control cores)
14 cores (cores for calculating the predicted cylinder air volume)

Claims (6)

Implements delay control to delay the change in the actual throttle opening relative to the change in the target throttle opening calculated from the accelerator opening, and predicts the in-cylinder air amount to be achieved in the future from the target throttle opening In the control device,
The prediction control device has a plurality of cores each set with a different prediction time,
Each of the plurality of cores is configured to calculate a predicted in-cylinder air amount that will be achieved in the future by the set predicted time when the delay control is performed using the set predicted time as a delay time based on the target throttle opening. Calculate
The prediction control device selects any one of the predicted in-cylinder air amounts calculated by each of the plurality of cores, and sets the predicted time set in the core that gives the selected predicted in-cylinder air amount A predictive control apparatus for an engine, wherein the delay control is performed using a delay time as a delay time.   2. The engine according to claim 1, wherein the predictive control device stops a part of the plurality of cores when the change amount of the accelerator opening is smaller than a first threshold value. Predictive control device. The predictive control device stops cores other than the core having the shortest predicted time when the change amount of the accelerator opening is larger than the second threshold set to a value larger than the first threshold. The predictive control apparatus for an engine according to claim 2 , wherein The predictive control system, when the amount of change in a certain time the accelerator opening is followed by a small state than the third threshold value, the longest predicted time is configured so that stop the core other than the core that has been set,
The third threshold value is a change amount of an accelerator opening that can be determined to be in a steady running mode in which there is no movement of the throttle when a state smaller than that lasts for a certain period of time. The engine predictive control device according to any one of claims 1 to 3.   5. The predictive control device selects the predicted in-cylinder air amount calculated by the core for which a shorter predicted time is set as the change in the target throttle opening degree is steeper. The engine predictive control apparatus according to any one of the above. For each of the plurality of cores , the predictive control device uses a difference between the predicted in-cylinder air amount calculated in the current control cycle and the predicted in-cylinder air amount calculated in the previous control cycle as a change amount per control cycle. Calculate and select the predicted in-cylinder air amount calculated by the core with the longest prediction time from among the cores whose change amount is equal to or less than a predetermined value during acceleration, and the change amount is equal to or greater than the predetermined value during deceleration The engine predictive control device according to any one of claims 1 to 4, wherein a predicted in-cylinder air amount calculated by a core having the shortest prediction time among the cores is selected.

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