JP2540196B2 - Electronic control unit for engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electronic control device for an engine that performs distributed processing of signal input / output processing and various control amount calculation processing.

[Prior Art] In recent years, electronic technology has been introduced into vehicles such as automobiles, and various controls, that is, power train control of engines and transmissions, vehicle control of suspensions, brakes, and car air conditioners have been electronically controlled. . The electronic control of this automobile is performed by, for example, a microcomputer, and in the engine, the electronic control by the microcomputer has achieved the improvement of exhaust emission and the improvement of fuel consumption.

The electronic control of the engine by the microcomputer is usually performed by a microprocessor (CPU) 50, a read-only memory (as shown in FIG. 5) as disclosed in, for example, JP-A-60-93150. ROM) 51, read / write memory (RAM) 52, input interface 53,
And an output interface 54 and the like are connected via a bus line 55, and are realized by an electronic control unit 56 centered on a microcomputer.

Input interface 53 of the above microcomputer
Various sensors 57 for detecting the operating state of the engine are connected to the output interface 54 via a waveform shaping circuit and the like, and actuators 59 such as an injector and an ignition coil are connected to the output interface 54 via a drive circuit 58. Are connected. The CPU 50 fetches various input signals from various sensors 57 indicating the engine operating state according to a control program stored in the ROM 51 as input data at a predetermined timing via the input interface 53, and temporarily stores them in the RAM 52. To do. The various input data stored in the RAM 52 is read by the CPU 50 at a predetermined timing, the fuel injection amount, the control amount such as the ignition timing is calculated based on these data, and the control signal corresponding to the control amount is output. It is output to the drive circuit 58 via the output interface 54. As a result, actuators 59 such as an injector and an ignition coil are driven to perform engine control such as air-fuel ratio control and ignition timing control.

Here, in general, the calculation of the fuel injection amount or the ignition timing is performed in synchronization with the rotation of the engine, but since the CPU 50 cannot perform various processes at once, for example, first, the CPU 50 sets a predetermined value according to a control program. Input signals from the sensors 57 are read at the timing, and various parameters representing the engine operating state such as the intake air amount and the engine speed are calculated from the input signals. After that, the basic amount of the fuel injection amount is calculated based on the above various parameters at regular time intervals, and then the ignition timing is calculated at each predetermined crank angle. Further, the fuel injection amount or the correction amount of the ignition timing is calculated, the final fuel injection amount, the control amount of the ignition timing, etc. is obtained, and the control signal corresponding to the control amount is output to the output interface 54 at a predetermined timing. Through the drive circuit
Output to 58. This procedure is repeated in synchronization with engine rotation.

However, when the input signals from the above-mentioned sensors 57 are read, the parameters representing the engine operating state are calculated from these input signals, and when the input processing of the signal for storing the parameters in the RAM 52, the amount or frequency of data increases, this input The time spent on processing cannot be ignored. Further, the inputs from the various sensors 57 are not necessarily synchronized with the engine rotation, and a situation in which the arithmetic processing is often interrupted due to an interruption of these asynchronous data, while the arithmetic processing is prioritized. As a result, the control amount cannot always be calculated based on the latest data, and accurate engine control becomes difficult.

That is, when there is no processing time, such as during high-speed engine operation, the overhead of input processing of the input signals from the various sensors 17 increases with respect to the processing time of the CPU 50, and the load of the CPU 50 increases. Therefore, there is a possibility that the calculation processing of the original fuel injection amount, ignition timing, etc. may not be in time, and the load on the CPU will increase, which will interfere with air-fuel ratio control or ignition timing control.

It should be noted that Japanese Patent Laid-Open No. 59-85441 (first prior art example) discloses that an electronic control unit for an engine is provided with two microcomputers, and the main microcomputer responds to required data indicating an engine operating state. The operation control processing is performed, and other operation control processing is performed in response to other data indicating the engine operation state by the auxiliary microcomputer and required data calculated by the main microcomputer, and the engine operation is performed from each microcomputer. By outputting a control signal to each engine operation control unit (actuator) that adjusts the state to control the engine operation state, various operation controls are shared by a plurality of microcomputers, and various control functions are enhanced. Corresponding techniques are disclosed.

However, in the first prior art example described above, each microcomputer is designed to perform signal input / output processing and control amount calculation processing, and the input / output processing and calculation processing are not individualized. There is a disadvantage that the processing and the control amount calculation processing cannot be performed in parallel, the execution time cannot be shortened, and the efficiency is low.

To deal with this, Japanese Patent Laid-Open No. 59-108847 (second prior art) discloses a plurality of electronic control devices for an engine.
By having a CPU and sharing functions, one CPU performs I / O control, and the other CPU performs internal control and data processing, which simplifies control of individual CPUs, improves efficiency, and enables parallel operation. A technique for reducing the execution time is disclosed.

[Problems to be Solved by the Invention] However, both the first and second prior examples have the following disadvantages.

In the first prior art example, the auxiliary microcomputer calculates the control amount by using the parameter representing the engine operating state which is processed by the main microcomputer, so that the timing of access to the RAM in each microcomputer is appropriately set. Must be taken individually. That is, when the parameter data is read by accessing the RAM at the request of the auxiliary microcomputer during the writing of the above-mentioned parameter data to the RAM in the main microcomputer, the parameter in the middle of rewriting is read, and the appropriate parameter is read. As a result, the control amount calculated by the auxiliary microcomputer based on this parameter becomes inadequate.By using this control amount for engine control, engine control accuracy and engine controllability deteriorate. Will end up.

Also in the second prior example, R in multiple CPUs
It is necessary to properly time each access to AM. That is, while one CPU for I / O control is writing parameter data to RAM, the other CPU for internal control
When the RAM is accessed and the parameters are read out at the request of the CPU, the parameters being rewritten are read out, and proper parameters cannot be obtained. As a result, the CPU for internal control calculates based on this parameter. The control amount becomes improper, and the use of this control amount deteriorates the engine control accuracy and the engine controllability.

Furthermore, in order to divide the functions of I / O control and internal control among multiple CPUs, synchronize the CPUs and
Since it is necessary to perform data communication between PUs, there is also a disadvantage that the load of software and programs increases correspondingly and the program execution load of the CPU becomes heavy.

In view of the above circumstances, the present invention is capable of distributing input / output processing and arithmetic processing to transfer each data at high speed.
Provided is an electronic control device for an engine, which can reduce the load on the CPU, can always obtain input data and control data properly, improve reliability of each data, and improve engine controllability. The purpose is to do.

[Means for Solving the Problems] In order to achieve the above object, an electronic control unit for an engine according to the present invention is a control amount for an engine operation control unit that adjusts an engine control amount based on an input signal from an engine operation state detection unit. In the electronic control unit of the engine for controlling the engine by outputting a control signal according to the control amount to the engine operation control means, and reading the input signal from the engine operation state detection means to represent the engine operation state. Various parameters are calculated and the main arithmetic processing means is interrupted to transmit the various parameters via the transmission connection means, and a control signal corresponding to the control amount calculated and transmitted by the main arithmetic processing means at every predetermined timing. Calculated by the dependent calculation processing means and the dependent calculation processing means for outputting to the engine operation control means. A main arithmetic processing means for calculating a control amount for the engine operation control means on the basis of various parameters and transmitting the control amount data to the subordinate arithmetic processing means via the transmission connection means.

Further, it is desirable that the transmission connection means is composed of a dual port RAM or a bus arbiter.

Furthermore, it is preferable that the execution program of the subordinate arithmetic processing means is stored in the main arithmetic processing means, and the execution program is transferred to the subordinate arithmetic processing means at the time of initialization of the system.

[Operation] In the present invention, the subordinate arithmetic processing means calculates the parameter representing the engine operating state based on the input signal from the engine operating state detecting means, interrupts the main arithmetic processing means, and the above parameter is the main arithmetic processing means. To the subordinate arithmetic processing means via the transmission connection means, and the main arithmetic processing means calculates the control amount for the engine operation control means based on the parameter and the control amount data is transmitted to the subordinate arithmetic processing means via the transmission connection means. Further, the subordinate arithmetic processing means outputs a control signal according to the control amount to the engine operation control means at every predetermined timing.

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

The drawings show one embodiment of the present invention, FIG. 1 is a functional block diagram of an electronic control unit, FIG. 2 is a schematic diagram of an engine control system, and FIG. 3 is a flow chart showing a control procedure of a main arithmetic processing means. FIG. 4 is a flowchart showing the control procedure of the subordinate arithmetic processing means.

In FIG. 2, reference numeral 1 is an engine body, and in the figure, a horizontally opposed four-cylinder engine is shown. The intake port formed in the cylinder head 2 of the engine body 1
An intake manifold 3 and an exhaust manifold 4 are connected in series to the exhaust port 2a and the exhaust port 2b, and a spark plug 5 for exposing the ignition portion of the cylinder head 2 to the combustion chamber 1a is attached to the cylinder head 2.

A throttle chamber 7 is connected to the upstream side of the intake manifold 3 via an air chamber 6, and the upstream side of the slot chamber 7 is connected to an air cleaner 9 via an intake pipe 8.

Further, an intake air amount sensor (a hot wire type air flow meter in the figure) 10 is provided immediately downstream of the air cleaner 9 in the intake pipe 8, and a throttle valve 7a provided in the throttle chamber 7 is provided with a throttle valve 7a. The position sensor 11 and the idle switch 11a are arranged in series.

Further, the combustion chamber of each cylinder of the intake manifold 3
An injector 12 is arranged immediately upstream of each suction port 2a communicating with 1a. Further, a cooling water temperature sensor 13 is exposed to a cooling water passage (not shown) formed in the intake manifold 3.

A crank rotor 14 is fixedly mounted on the crank shaft 1b of the engine body 1.
A crank angle sensor 15 is provided opposite to the outer circumference of 14.

Further, an O2 sensor 17 is exposed to the exhaust pipe 16 communicating with the exhaust manifold 4. Reference numeral 18 is a catalytic converter.

On the other hand, reference numeral 19 is an electronic control unit mainly composed of a microcomputer, which is a master processor (master CP).
U) 20, read only memory (ROM) 21, read / write memory (RAM) 22 are connected via a bus line 23, and
Similarly, slave processor (slave CPU) 24, read-only memory (ROM) 25, read / write memory (RAM) 26
Are connected via a bus line 27. Master CP above
U20 and the slave CPU 24 are the bus line 23,
27 are connected to each other via an interface 28, and further, the slave CPU 24 is connected to the sensors, switches 10, 11, 11a, 13, 15, 15 through the input port of the input / output (I / O) interface 29. 17 connected and also this I /
The injector 12 and the ignition coil 31 are connected to an output port of the O interface 29 via a drive circuit 30. The spark plug 5 is connected to the secondary side of the ignition coil 31 via a distributor 32.

Fixed data such as a control program is stored in the ROM 21 connected to the master CPU 20, and the RAM 22 has a work area for arithmetic processing of various control data in the master CPU 20, and an arithmetic operation. A data buffer for temporarily storing processed control data and the like is provided. In the master CPU 20, each sensor by the slave CPU 24 described later, based on various parameters representing the engine operating state calculated based on the input signal from the switches, the fuel injection amount and the ignition timing according to the control program stored in the ROM 21. Control amount calculation processing such as is performed.

On the other hand, the ROM 25 connected to the slave CPU 24 stores an input / output processing program, and the slave CPU 24 includes the sensors, switches 10, 11, 11a, 13, 1
5, 17 input signals from, to calculate various parameters representing the engine operating state, and the injector 12, ignition coil 31 a predetermined control signal according to the control amount calculated by the master CPU 20. Performs input / output processing of signals output at timing. Further, in the RAM 26, each of the sensors, a work area when calculating various parameters from the input signals of the switches 10, 11, 11a, 13, 15, 17, and
A data buffer for temporarily storing various calculated parameters is also provided. The ROM 25 is omitted, and the input / output processing program is stored in the ROM 21 connected to the master CPU 20. When the system is initialized, the master CPU 20 transfers the input / output processing program from the ROM 21 to the RAM 26. It may be done.

That is, the slave CPU 24 takes in signals from the intake air amount sensor 10, the throttle position sensor 11, the idle switch 11a, the cooling water temperature sensor 13, the crank angle sensor 15, and the O2 sensor 17 at a predetermined timing, and takes in the intake air. Various parameters representing the engine operating state such as the quantity Q, the throttle opening θ, the cooling water temperature Tw, the engine speed, and the air-fuel ratio feedback correction coefficient α are calculated. These various parameters are
Sent to the master CPU20 via the
Then, the control amount such as the fuel injection amount Ti and the ignition timing θIG is calculated based on the received various parameters, and the control amount data is transmitted to the slave CPU 24. Then, the slave CPU 24 performs a signal output process of outputting a control signal corresponding to the control amount to the injector 12 or the ignition coil 31 at every predetermined timing.

Next, the functional configuration of the electronic control unit 19 will be described with reference to FIG. As shown in FIG. 1, the electronic control unit 19 is composed of subordinate arithmetic processing means 33, transmission connecting means 34, main arithmetic processing means 35, and drive circuit 30.

In the subordinate arithmetic processing means 33, the intake air amount sensor 10,
Throttle position sensor 11, idle switch 11a,
Each signal such as the cooling water temperature sensor 13, the crank angle sensor 15, the O2 sensor 17 and the like, and the input signal from the engine operating state detecting means 36 including switches are read and processed to calculate various parameters representing the engine operating state. The main arithmetic processing means 35 is interrupted and the various parameters are transmitted to the main arithmetic processing means 35 via the transmission connection means 34. Further, the subordinate arithmetic processing means 33, via the drive circuit 30, the control signal corresponding to the control amount data calculated by the main arithmetic processing means 35 and transmitted through the transmission connecting means 34 at predetermined timing. 12, output to the engine operation control means 37 including actuators for adjusting the engine control amount of the ignition coil 31 and the like. This subordinate processing means
33 is specifically the slave CPU 24, ROM2 shown in FIG.
5, RAM 26 is connected by a bus line 27.

The transmission connection means 34 transfers data between the subordinate arithmetic processing means 33 and the main arithmetic processing means 35, and specifically, a parallel interface, a serial interface, a dual port RAM, or the like. Composed by. The transmission connection means 34 is the master.
The CPU 20, the slave CPU 24, the ROMs 21, 25, and the RAMs 22, 26 may be connected by the same bus, and may be configured by a bus arbiter that arbitrates the bus usage of the master CPU 20 and the slave CPU 24 to prevent access conflict.

In the main arithmetic processing means 35, the subordinate arithmetic processing means 33
The control amount for optimally controlling the engine operation control means 37 according to the engine operating state is calculated based on the various parameters calculated by the above, and the control amount data is subjected to the subordinate calculation processing via the transmission connection means 34. To the means 33. The main arithmetic processing means 35 is specifically configured by connecting the master CPU 20, ROM 21 and RAM 22 shown in FIG.

With the above configuration, the signal input / output processing of the signal input processing from the engine operating state detection means 36 and the control signal output processing to the engine operation control means 37 is performed by the subordinate calculation processing means 33, and the control amount calculation processing is performed. This is performed by the main arithmetic processing means 35. Therefore, conventionally, the input / output processing of the signal and the arithmetic processing of the control amount, which have been processed serially in time according to a predetermined procedure, are completely shared by the subordinate arithmetic processing means 33 and the main arithmetic processing means 35, respectively, and the parallel arithmetic Processing can be performed, execution time can be shortened, efficiency can be improved, and execution load of the CPU in the electronic control unit 19 can be significantly reduced.

Next, the control procedure of the electronic control unit 19 will be described with reference to the flowcharts of FIGS. 3 and 4.

First, the arithmetic processing by the main arithmetic processing means 35 will be described. Initialization is performed in step S100, and then the process proceeds to step S101, in which a data buffer provided in the RAM 22 receives various parameters representing the engine operating state processed by the slave CPU 24. To see if it has been done. If there is no parameter data in the above data buffer, step
The process proceeds to S105, requests the slave CPU 24 for data, and returns to step S101 to wait for the data to be received.

When the data buffer has the various parameters, the process proceeds to step S102, the parameters are picked up, and then, in step S103, the control amount such as the fuel injection amount Ti is calculated based on the parameters.

In step S104, the data of the control amount calculated in step S103 is output to the slave CPU 24 via the transmission connection means 34, for example, by an interrupt, and then the process returns to step S101. Then, the above procedure is repeated to calculate the control amount of the ignition timing θIG, for example, and output it to the slave CPU 24. The control amount data calculated by the master CPU 20 may be stored in the dual port RAM which is a shared memory of the master CPU 20 and the slave CPU 24.

Next, a control procedure in the subordinate arithmetic processing means 33 will be described.

First, initialization is performed in step S200, the process proceeds to step S201, it is determined whether it is time to output a control signal to a predetermined engine operation control means 37, and when the output time of the control signal is reached, Go to step S206,
The control amount data calculated and transmitted by the master CPU 20 and stored in the data buffer in the RAM 26 is read out, and the process proceeds to step S207.

In step S207, the control amount data is output to a predetermined I / O address, a control signal corresponding to the control amount is output to the engine operation control means 37 via the drive circuit 30, and the injector 12 or the ignition coil 31 is output. And drive. Then, the process returns to step S201.

On the other hand, in step S201, when it is not the time to output the control signal, the process proceeds to step S202, where the sensor of the engine operating state detection means 36 receives signals from the switches,
The process proceeds to step S203, and if no signal is input, the process returns to step S201.

In step S203, an input signal is fetched from a predetermined I / O address, the process proceeds to step S204, and a parameter representing the engine operating state is calculated from this input signal.

Next, proceeding to step S205, the master CPU 20 is interrupted, and the parameters calculated at step S204 are output. Then, the process returns to step S201 and the above procedure is repeated. The various parameters indicating the engine operating state may be stored in the dual port RAM described above.

According to the first aspect of the present invention, the subordinate arithmetic processing means calculates the parameter representing the engine operating state based on the input signal from the engine operating state detecting means, and interrupts the main arithmetic processing means. The parameter is transmitted to the main arithmetic processing means via the transmission connecting means, the main arithmetic processing means calculates the control amount for the engine operation control means based on the parameter, and the control amount data is transmitted to the transmission connecting means. Is transmitted to the subordinate arithmetic processing means via the subordinate arithmetic processing means, and the subordinate arithmetic processing means outputs a control signal corresponding to the control amount to the engine operation control means at every predetermined timing. It becomes possible to completely divide the arithmetic processing of and the sub arithmetic processing means and the main arithmetic processing means, respectively, and perform parallel processing.
Efficiency can be improved by shortening the execution time by parallel operation, each data can be transferred at high speed, and the load on each CPU constituting each arithmetic processing means can be reduced.

Further, since the parameter calculated by the subordinate arithmetic processing means is transmitted to the main arithmetic processing means by interrupting the main arithmetic processing means after the parameter calculation by the subordinate arithmetic processing means, the parameter data in the middle of rewriting is mainly used. The parameter data representing the engine operating state is always properly and accurately supplied to the main processing unit without being transmitted to the processing unit, and is calculated by the main processing unit to the dependent processing unit. It is possible to always obtain an appropriate value for the transmitted control amount, and the control signal output to the engine operation control means is always accurate according to this control amount, and the reliability of each data and control signal is improved. It is possible to improve the engine operating condition and to maintain the engine operating condition optimally, and improve the engine control accuracy and engine controllability. Improvement of engine output performance by,
It is possible to improve exhaust emission and fuel efficiency.

According to the second aspect of the present invention, in addition to the effect of the first aspect, the transmission connection means has a dual port RA.
Multiple C by configuring with M or bus arbiter
It is possible to reduce the program execution load on each CPU by suppressing an increase in the load of software and programs that require data communication between CPUs when the PUs share the functions.

Further, according to the third invention of claim 3, the first
In addition to the effects of the invention or the second aspect of the invention, the execution program of the subordinate arithmetic processing means is stored in the main arithmetic processing means, and the subordinate arithmetic processing means is transferred to the subordinate arithmetic processing means at the time of system initialization. It is possible to reduce the ROM and the memory capacity in the above, and it is possible to reduce the cost.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a functional block diagram of an electronic control unit, FIG. 2 is a schematic diagram of an engine control system,
FIG. 3 is a flow chart showing the control procedure of the main calculation processing means, FIG. 4 is a flow chart showing the control procedure of the dependent calculation processing means, and FIG. 5 is a circuit block diagram showing a conventional example. 19 ... Electronic control device, 33 ... Subordinate processing means, 34 ... Transmission connecting means, 35 ... Main processing means, 36 ... Engine operating state detecting means, 37 ... Engine operating control means.

Claims (3)

(57) [Claims] 1. A control amount for an engine operation control unit for adjusting an engine control amount is calculated based on an input signal from an engine operation state detection unit, and a control signal corresponding to the control amount is output to the engine operation control unit. In the electronic control unit of the engine that controls the engine by reading the input signal from the engine operating state detection means,
Control parameters calculated by the main arithmetic processing means and transmitted at a predetermined timing while calculating various parameters representing the engine operating state and interrupting the main arithmetic processing means to transmit the parameters via the transmission connection means. Dependent calculation processing means for outputting a control signal according to the data to the engine operation control means, and a control amount for the engine operation control means is calculated based on various parameters calculated by the dependent calculation processing means, and the control amount data is obtained. An electronic control unit for an engine, comprising: a main arithmetic processing means for transmitting to the subordinate arithmetic processing means via a transmission connection means. 2. The electronic control unit for an engine according to claim 1, wherein said transmission connection means is constituted by a dual port RAM or a bus arbiter. 3. The main arithmetic processing means stores an execution program for the subordinate arithmetic processing means, and the execution program is transferred to the subordinate arithmetic processing means when the system is initialized. The electronic control unit for an engine according to claim 1 or claim 2.