JP5673576B2 - Engine control device - Google Patents

Description

  The present invention relates to an automobile engine control apparatus, and more particularly to an engine control apparatus equipped with a multi-core processor.

  2. Description of the Related Art Conventionally, an arithmetic device equipped with a plurality of CPUs, that is, an automobile engine control device equipped with a multiprocessor is known. One described in JP 2010-196619 A (hereinafter referred to as Patent Document 1) is one such engine control device. In the engine control device disclosed in Patent Document 1, each processor processes interrupt routines in order in synchronization with the crank angle, thereby placing each processor on a processing load regardless of the engine speed. It can be distributed evenly.

  In recent years, it has been proposed in various fields to use an arithmetic device having a plurality of cores mounted on one CPU, that is, a multi-core processor. The use of multi-core processors is also being studied in the field of automotive engine control. For example, the above-mentioned Japanese Unexamined Patent Application Publication No. 2010-196619 refers to the application of the technique described in the publication to a multi-core processor.

JP 2010-196619 A JP 2007-125950 A JP 2008-269487 A

  One of the problems in multi-core processors is the reduction of power consumption. This is true even when the multi-core processor is mounted on the engine control apparatus. However, it is not easy to achieve the above problem with the technique described in Patent Document 1. More specifically, when a task is processed in synchronization with the crank angle, the time limit for the processing time becomes shorter when the engine speed is high and becomes longer when the engine speed is low. For this reason, the calculation speed of the core must be set in accordance with the high rotation speed with a short time limit. However, when such a setting is used, the time limit for the task processing time increases when the engine is running at a low speed, and the idle state until the next calculation becomes longer. Since power is consumed even in the idle state, if the ratio of the idle state is large, unnecessary power is consumed accordingly.

  The present invention has been made in view of the above problems, and an object thereof is to reduce the power consumption of an engine control apparatus equipped with a multi-core processor.

  In order to achieve the above object, an engine control apparatus according to the present invention is configured as follows.

  The engine control apparatus according to the present invention processes the crank angle synchronization task among the tasks processed by the multi-core processor by the first core, and processes the time synchronization task by the second core. That is, the core that processes the crank angle synchronization task and the core that processes the time synchronization task are separated. While the execution period of the crank angle synchronization task changes depending on the engine speed, the execution period of the time synchronization task is constant regardless of the engine speed, so the second core that processes only the time synchronization task is It is easy to optimize the clock frequency so that the idle state is minimized. By optimizing the clock frequency, the power consumption of the second core can be reduced to a minimum. The first core and the second core may each be singular or plural.

  Further, the engine control apparatus according to the present invention outputs the actuator operation amount calculated based on the accelerator pedal opening degree to the actuator after delaying it by a predetermined delay time instead of outputting it to the actuator immediately. That is, delay control is performed with respect to the actuator operation amount. The actuator operation amount here is an operation amount of an actuator that controls the torque of the engine, and is a fuel injection amount when the engine to be controlled is a diesel engine. When the engine to be controlled is a gasoline engine, the throttle opening is obtained. Although these actuator operation amounts affect the engine speed, according to the delay control, the actuator operation amount calculated from the required torque does not affect the latest engine speed but the future engine speed after the delay time. . Therefore, the engine control apparatus according to the present invention predicts a rapid increase in the engine speed after the delay time based on the actuator operation amount calculated from the required torque.

  The engine control apparatus according to the present invention calculates a time limit for the processing time of the crank angle synchronization task based on the current engine speed. If the engine speed is high, a short time limit is calculated, and if the engine speed is low, a long time limit is calculated.

  The engine control apparatus according to the present invention sets the processing time of the crank angle synchronization task by the first core to the time limit if the engine speed is predicted not to increase rapidly in the prediction based on the actuator operation amount. Adjust the clock frequency to match. That is, the clock frequency is adjusted so that the operating rate of the first core is maximized. By eliminating the idle state and maximizing the operating rate, the clock frequency and driving voltage of the first core can be minimized, and the power consumption of the first core is reduced to the minimum.

  On the other hand, when it is predicted that the engine speed will increase rapidly in the prediction based on the actuator operation amount, the engine control device according to the present invention fixes the clock frequency of the first core to the maximum. According to this, since the processing time of the crank angle synchronization task can be minimized, no matter how much the engine speed increases rapidly and the time limit becomes shorter, the processing time will not exceed the time limit. It can be avoided.

  According to the present invention, it is possible to reduce the power consumption of an engine control device equipped with a multi-core processor.

It is a block diagram which shows the outline of a structure of the multi-core processor which the engine control apparatus as embodiment of this invention mounts. It is a flowchart which shows the procedure of the clock frequency control which the engine control apparatus as embodiment of this invention performs. It is a figure which shows the image of the operating state of the core in the core which processes a time synchronous task. It is a figure which shows the image of the operating state of a core at the time of optimizing a clock frequency in the core which processes a time synchronous task.

  Embodiments of the present invention will be described with reference to the drawings.

  The engine control device as the present embodiment is configured as a control device for a diesel engine. There is no limitation on the structure of the diesel engine to be controlled. The engine control device calculates the amount of fuel to be injected into the injector based on the accelerator pedal opening. However, this engine control device is configured to perform delay control with respect to fuel injection control. According to the delay control, the fuel injection amount calculated based on the accelerator pedal opening is not immediately output to the injector, but is output to the injector after a predetermined delay time (for example, 32 msec, 64 msec). Therefore, since the fuel injection amount calculated at the present time becomes a predicted value of the future fuel injection amount after the delay time, the engine operating state after the delay time, for example, the engine speed and the engine load, is predicted from this value. be able to.

  This engine control device is equipped with a multi-core processor and processes various tasks by the multi-core processor. Tasks processed by the engine control device include a crank angle synchronization task that is executed every time the crankshaft rotates by a predetermined angle, and a time synchronization task that is executed at a predetermined time period (for example, 8 msec, 16 msec, and 32 msec). And tasks. There is a difference between the crank angle synchronization task and the time synchronization task, in which the execution period of the former changes depending on the engine speed, whereas the latter has a constant execution period regardless of the engine speed.

  FIG. 1 is a block diagram showing an outline of the configuration of a multi-core processor installed in the engine control apparatus. The multi-core processor according to the present embodiment includes a first core 11, a second core 12, and a controller 2. The first core 11 is a core in charge of processing of the crank angle synchronization task, and the second core 12 is a core in charge of processing of the time synchronization task. In addition, although the 1st core 11 and the 2nd core 12 are each drawn in FIG. 1, the 1st core 11 and the 2nd core 12 can also be provided with two or more, respectively. When a plurality of first cores 11 are provided, a plurality of crank angle synchronization tasks can be distributed among the cores. Similarly, when a plurality of second cores 12 are provided, a plurality of time synchronization tasks can be distributed among the cores.

  Each of the first core 11 and the second core 12 includes clock frequency control circuits 11a and 12a. The clock frequency control circuits 11a and 12a are circuits that change the clock frequency of the cores 11 and 12b. The clock frequency control circuits 11 a and 12 a are configured to change the clock frequency in combination with the drive voltages of the cores 11 and 12.

  The clock frequency control circuits 11 a and 12 a control the clock frequency according to a command from the controller 2. The controller 2 is realized as one function of the OS that manages each core of the multi-core processor. The controller 2 executes the clock frequency control for each of the cores 11 and 12 so as to maximize the operating rate of each of the cores 11 and 12, that is, to minimize the idle time during which no task calculation processing is performed. .

  FIG. 2 is a flowchart showing a procedure of clock frequency control of the first core 11 executed by the controller 2. The controller 2 executes the clock frequency control shown in this flowchart in synchronization with the crank angle. The controller 2 receives the crank angle signal output from the crank angle sensor and the fuel injection amount calculated based on the accelerator pedal opening in the delay control described above.

  In the first routine S1 in the flowchart of FIG. 2, whether or not the engine speed rapidly increases after the delay time has elapsed is predicted based on the fuel injection amount. When the delay control of the fuel injection amount is performed as in the present embodiment, the fuel injection amount calculated at the present time is output to the injector after the delay time, so that not the latest engine speed but the delay Affects future engine speed after hours. Therefore, the behavior of the engine speed in the future after the delay time can be predicted from the fuel injection amount calculated at the present time. For example, if the fuel injection amount does not change from the previous calculation, it can be predicted that the engine speed will not change, and if the fuel injection amount has changed from the previous calculation, the engine speed will also change. it can. Here, when the increase amount or the increase rate of the fuel injection amount exceeds a predetermined threshold value, it is predicted that the engine speed rapidly increases.

  If it is predicted in step S1 that the engine speed will not increase rapidly, the processes of steps S2, S3, S4 and S5 are executed. First, in step S2, a calculation amount for each half engine revolution is calculated for the crank angle synchronization task to be processed. In the next step S3, a time limit for the processing time of the crank angle synchronization task is calculated based on the current engine speed. The time limit calculated in step S3 is a short time if the engine speed is high, and a long time if the engine speed is low. In step S4, the minimum clock frequency required to process all the computation amounts calculated in step S2 is calculated within the time limit calculated in step S3. In the subsequent step S5, the drive voltage required to output the clock frequency calculated in step S4 is calculated.

  That is, when it is predicted that the engine speed will not increase rapidly, the controller 2 controls the clock frequency so that the clock frequency and drive voltage of the first core 11 are the clock frequency and drive voltage calculated in steps S4 and S5. The circuit 11a is controlled. As a result, the processing time of the crank angle synchronization task by the first core 11 is adjusted to the time limit for the current engine speed, and the first core 11 is kept from becoming idle. That is, the operating rate of the first core 11 is maximized. Thus, the power consumption of the first core 11 is reduced to the minimum by maximizing the operating rate of the first core 11 and reducing the clock frequency and the driving voltage as much as possible.

  On the other hand, if it is predicted in step S1 that the engine speed will increase rapidly, the processes of steps S6 and S5 are executed. In step S6, the clock frequency of the first core 11 is fixed to the maximum. In the subsequent step S5, the driving voltage required to output the maximum clock frequency determined in step S6 is calculated.

  That is, when it is predicted that the engine speed will rapidly increase, the controller 2 maximizes the clock frequency and drive voltage of the first core 11. According to this, since the processing time of the crank angle synchronization task can be minimized, the processing time of the crank angle synchronization task can be reduced no matter how much the engine speed increases and the time limit decreases. It is possible to avoid exceeding.

  Next, the clock frequency control of the second core 12 executed by the controller 2 will be described with reference to FIGS. FIG. 3 is a diagram showing an image of an operating state of the second core 12 when the clock frequency is not optimized with respect to the second core 12 that processes a time synchronization task having an execution period of 8, 16, and 32 msec. is there. As shown in this figure, when the clock frequency is not optimized, a long idle time such as “idle 1, 2, 3, 4” in the figure occurs.

  Therefore, the controller 2 acquires the operating rate of the second core 12 in the past 32 msec and identifies the section (idles 1 and 4 in FIG. 3) having the shortest idle time. Then, the clock frequency of the second core 12 is adjusted by controlling the clock frequency control circuit 12a so that the idle time in that section matches the predetermined reference value. The reference value is a minimum idle time corresponding to a margin that can cope with a change in the amount of calculation, and is calculated experimentally in advance. FIG. 3 is a diagram showing an image of the operating state of the second core 12 when the clock frequency is optimized in this way. As shown in FIG. 3, the power consumption of the second core 12 can be reduced to the minimum by increasing the operating rate of the second core 12 and lowering the clock frequency and the drive voltage.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. The present invention can be applied not only to a diesel engine control device but also to a gasoline engine control device. In that case, by performing delay control on the throttle opening calculated based on the accelerator pedal opening, it is possible to predict a rapid increase in engine speed after a delay time from the throttle opening.

2 Controller 11 First core 11a Clock frequency control circuit 12 Second core 12a Clock frequency control circuit

Claims (1)

In an engine control apparatus equipped with a multi-core processor and processing a crank angle synchronization task and a time synchronization task using the multi-core processor,
A first core responsible for processing the crank angle synchronization task;
A second core responsible for processing the time synchronization task;
A delay control means for calculating an operation amount of an actuator used for torque control based on an accelerator pedal opening; and delaying the operation amount by a predetermined delay time and outputting the operation amount to the actuator;
Predicting means for predicting a sudden increase in engine speed after the delay time based on the operation amount;
Time limit calculating means for calculating a time limit for the processing time of the crank angle synchronization task based on the current engine speed;
When the engine speed is not predicted to increase rapidly by the predicting means, the clock frequency of the first core is adjusted so that the processing time of the crank angle synchronization task by the first core matches the time limit. And when the engine speed is predicted to be suddenly increased by the prediction means, a clock frequency control means for fixing the clock frequency of the first core to a maximum;
An engine control device comprising:

Images