JPS61232363A - Electronic controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To aim at enlargement in a processing quantity and reduction in its processing time as a whole, by installing two central processing units controlling each control over fuel supplying and ignition separately each, while connecting an interval between both these units via a date transmitting channel line. CONSTITUTION:Inside an electronic controller, there are provided with a first central processing unit 1 taking charge of fuel supply control and a second central processing unit 2 taking charge of ignition timing control, and a PB (absolute pressure inside a suction pipe) transducer 5 and another transducer 6 related to other driving parameters both are connected to the input side of the CPU 1. Likewise, a waveform shaping circuit 13, where a cylinder discriminating sensor 14, a top dead point sensor 15 and a crank angle sensor 16 are all connected, is connected to the input side of the CPU 2. And, an interval between both these units 1 and 2 is connected via data transmitting channel lines 27 and 28 whereby each detection value of various driving parameters to be inputted into each of these CPUs 1 and 2 is made transmittible to each other. And, a fuel injection valve 8 or the like is controlled by the CPU 1 while an ignition circuit 21 by the CPU 2, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an electronic control device for an internal combustion engine, and more particularly to an electronic control device equipped with a central processing unit that separately controls fuel supply and ignition.

(Technical background of the invention and its problems) As a conventional electronic control device for controlling the fuel injection amount and ignition timing of an internal combustion engine, for example, Japanese Patent Laid-Open No. 53-762
There are some such as those disclosed in No. 31. This electronic control unit consists of one central processing unit (hereinafter referred to as rCP).
Equipped with UJ).

In addition to this, there is an engine water temperature signal, an absolute pressure signal in the intake pipe, a rotational position signal of the engine crankshaft, that is, a crank angle signal generated every time the crankshaft rotates by a predetermined angle, and two signals per rotation. Engine operating parameters such as generated reference position signals are introduced, and based on these input signals, both calculations related to fuel injection amount control and ignition timing control are executed by this common CPU.

Incidentally, in recent years, in order to meet the demands for improved driving performance, the content of the calculation program for each controlled object has become more complex, and the amount of processing executed by the CPU has increased.

However, in conventional electronic control devices.

Since a common CPU performs arithmetic processing on a plurality of control objects, it becomes impossible to cope with the increase in the amount of arithmetic processing for each control object as described above.

In particular, it is difficult to meet the demand for more accurate engine control at high engine speeds, where the time available for arithmetic processing is shorter than at low engine speeds. Although it would be possible to meet the above requirements by using a CPU with the highest arithmetic processing capability (for example, 32-bit, 64-bit, etc.), this would be impractical as it would increase costs. On the other hand, if multiple control targets can be individually processed and the engine operating parameters necessary for each CPU are taken in by separate sensors, input circuits, etc., each CPU, including its input circuit, etc. Since a plurality of devices are required, the device becomes complicated and bulky, making maintenance difficult.

(Object of the Invention) This invention has been made in view of the above points, and its purpose is to control each of multiple control targets such as fuel injection amount and ignition timing without complicating the device. An object of the present invention is to provide an electronic control device for an internal combustion engine that enables more accurate and complicated control of the engine.

(Structure of the Invention) In order to achieve the above object, the present invention includes a fuel supply means for supplying fuel to an internal combustion engine, and an ignition means for igniting an air-fuel mixture formed by the supplied fuel. In an electronic control device for an internal combustion engine, a first central processing unit that controls the fuel supply, a second central processing unit that controls the ignition, and a second central processing unit that is connected to the first central processing unit. , a first detection means for detecting a first engine operating parameter; a second detection means connected to the second central processing unit and detecting a second engine operating parameter; a signal transfer means interposed between the two central processing units and mutually transfers each detected value of the first engine operating parameter and the second engine operating parameter; The central processing unit is the first and second processing unit.
An electronic control device for an internal combustion engine is provided, wherein the fuel supply and the ignition are respectively controlled based on engine operating parameters.

(Embodiments of the invention) Examples of the invention will be described below based on the drawings. 1st
The figure is a diagram showing the overall configuration of an electronic control device according to the present invention. An electronic control unit (ECU) includes a first CPU 1 that controls fuel supply to the internal combustion engine, and a second CPU that controls ignition timing of the air-fuel mixture formed by the supplied fuel.
U2 is provided. The first CPU 1 has a read-only memory that stores various calculation programs executed by the first CPU 1 and various tables used to calculate the fuel injection amount, in other words, the opening time of the fuel injection valve 8. (hereinafter referred to as rROMJ) Random access memory (hereinafter referred to as rRA) that temporarily stores 3° calculation results, etc.
MJ) 4 is provided. On the input side of the first CPU, there is a P that detects the value of the absolute pressure inside the intake pipe (not shown) of the internal combustion engine, converts it into a digital value, and outputs the value.
The B transducer 5 is connected to another transducer 6 that detects operating parameter values such as intake air temperature, engine cooling water temperature, throttle valve opening, and 02 concentration in exhaust gas, converts them into digital values, and outputs them. ing. These transducers 5 and 6 constitute a first detection means. Further, a counter circuit 7 that counts the opening time of the fuel injection valve based on fuel injection time data to be described later is connected to the output side of the first CPU 1, and an output line of this counter circuit 7 is connected to the fuel injection valve 8. It is connected. These counter circuit 7, fuel injection valve 8, etc. constitute a fuel supply means. Further, drive signal lines for the EGR valve, solenoid valve for idle control, etc. are connected to actuators 9 for these valves. Note that the fuel injection valve 8 is arranged for each cylinder of the internal combustion engine, and accordingly, the counter circuit 7 is also provided with the same number of counters as the number of cylinders.

On the other hand, the second CPU 2 includes a ROM II and a RAM that have the same functions as the first CPU 1.
12 are provided. A waveform shaping circuit 13 is connected to the input side of the second CPU, and a sensor for detecting the rotational position of the engine crankshaft is connected to the input side of the waveform shaping circuit 13.
That is, a cylinder discrimination (CYL) sensor 14 outputs a one-pulse signal To for cylinder discrimination at a predetermined crank angle position of a specific cylinder of the engine. The engine crankshaft is 180
A top dead center (TDC) sensor 15 outputs a reference crank angle signal T, 4 at a predetermined crank angle position of BTDC (before top dead center) of each cylinder every time the crankshaft rotates 30°. Each sensor of the crank angle sensor 16 that outputs a one-pulse signal T□ is connected. These sensors 14, 15, and 16 constitute a second detection means. Further, the output side of the second CPU 2 is connected to a flip-flop circuit 19 . Further, an ignition circuit 21 and a distributor 22 are sequentially connected to a subsequent stage, and spark plugs 23a to 23d arranged for each cylinder are connected to the distributor 22. The ignition circuit 21, the distributor 22, the ignition plugs 23a to 23d, and the like constitute an ignition means. The ignition circuit 21 includes one of the high pressure generation layers (not shown).
A well-known ignition coil is set up consisting of a primary coil and a secondary coil. Also turn-on counter 1
7 and the turn-off counter 18, down counters are used, and as will be described later, the turn-on counter 17 is set with energization start timing data calculated by the second CPU 2, and this is used to determine when to start energization, which will be described later. In the crank angle position range ff (hereinafter simply referred to as "energization stage"), the timing of energization to the primary coil of the ignition circuit 21 is determined by counting subtracted from the stage starting point using clock pulses. On the other hand, the turn-off counter 18 is set with the ignition timing data calculated by the second CPU 2 in the same manner as described above, and is subtracted from the start point of the stage at a predetermined ignition stage (described later) by clock pulses, and is sent to the primary coil. It determines when to cut off the current to the secondary coil and generates high voltage for ignition on the secondary coil side.

Furthermore, the following signal lines are connected between the first CPU 1 and the second CPU 2.

First, a signal line 25 for the cylinder discrimination (CYL) signal T0□ is connected between the output side of the waveform shaping circuit 13 and the input side of the first CPUI. In addition, a signal line 26 that gives a trigger number for starting calculations to the first CPU 2 is connected from the second CPU 2 to the first CPU 2, and communication lines 27 and 28 for data transfer are connected between both CPU 2. The communication line 28 connected to the first CPU 2 is for transferring data such as engine parameters and transmission command signals from the first CPU 2 to the second CPU 2, and the communication line 27 is connected to the second CPU 2.
This is for sending a confirmation signal, etc. in response to the above transmission command from the PU2 to the first CPUI. Each CPU1
, 2 are provided with a parallel-to-serial conversion circuit and a serial-to-parallel conversion circuit at the transmitting end and receiving end of each communication line 27, 28, respectively, in order to serially and asynchronously transfer data as described later. It is arranged. And each of these communication lines 27.28. The signal transfer means is composed of a parallel-to-serial conversion circuit, a serial-to-parallel conversion circuit, and the like. Reference numeral 29 is a Me counter, and this Me counter 29 includes a second C
A start trigger signal lead line 30 is connected from the PU2, and its output side is connected to the first CPUI. M
The e-counter 29 is controlled by the second CPU 2, for example, BTDC9.
The count value is stored in a register (not shown) by the start trigger signal generated when the 0° crank angle position is detected, the count value is reset to zero, and counting of clock pulses at a constant frequency is started again. . Therefore, the count value stored in the register of the Me counter 29 represents the number of clock pulses between the occurrence of the current and previous start trigger signals, that is, the time interval between the occurrences of the start trigger signal. The parameter Me is read by and used to calculate a parameter Me proportional to the reciprocal of the engine speed Ne, and this parameter Me is used as information representing the engine speed and as one of the parameters when calculating the fuel injection amount.

Next, as shown in FIG. 2, the parallel-serial conversion circuits and the series-
The parallel conversion circuit on the communication line 28 side will be explained.

Reference numeral 31 is a parallel-to-serial conversion circuit that adds 8-bit command or operating parameter value data, a command or data discrimination bit, and start and stop bits.
A latch circuit 32 latches 1 bit as 1 frame (Fig. 7), and 11-bit data input in parallel from this latch circuit 32 is input via a signal line 34, 1 bit for each clock pulse input. It is composed of a shift register 33 for serial transfer. The output terminal of the shift register 33 is the output port 35 and the communication line 28.
and is connected to the input end of the shift register 39 on the second CPU 2 side via the input port 36. This shift register 39 and latch circuit 38 constitute a serial-to-parallel conversion circuit 37, and the transferred 11-bit data is stored in the shift register 38 by the reverse procedure of the parallel-to-serial conversion circuit 31. Note that reference numeral 40 is an input line for clock pulses input to the shift register 39.

The clock pulses input from this input line 40 and the clock pulses input from the signal line 34 on the transmitting side are asynchronous, but have the same pulse generation period. A signal corresponding to a stop bit of data, which will be described later, is supplied from the shift register 39 to a clock input terminal of the latch circuit 38 via an output line 41, and a signal corresponding to a data stop bit, which will be described later, is supplied to the clock input terminal of the latch circuit 38, and a signal corresponding to a data stop bit, which will be described later, is supplied to the clock input terminal of the latch circuit 38, and a signal corresponding to a data stop bit, which will be described later, is supplied to the clock input terminal of the latch circuit 38. In this case, when data transfer for the first frame is performed, it is used as a signal to notify that the data transfer for the first frame has been completed.

Next, the operation will be explained with reference to FIGS. 3 to 7.

First, ignition timing control by the second CPU 2 will be described. - The second CPU 2 receives CYL from each sensor 14 to 16.
Signal T00, TDC signal T0 and crank angle signal T2. is waveform-shaped by the waveform shaping circuit 13 and input (
Figures 3(a)-(C)). Among these, CYL signal Tl11
is also input to the first CPUI via the signal line 25 as a signal for determining the order of fuel injection to each cylinder. Note that the stage in FIGS. 3 and 4 uses a crank angle signal T to measure the crank angle between two adjacent top dead centers (TDCs).
! The crank angle from each rise of T24 to the rise of the next crank angle signal T24 is divided into six regions at one interval, and each region is called a stage and numbered from 0 to 5. The second CPU 2 includes a crank interrupt processing program (FIG. 4 (b
)) and θIG-DU performed following the end of the crank interrupt processing program executed at the O-th stage.
Two processing programs, the TY calculation processing program (FIG. 4(C)), are executed, and when the crank angle signal T24 is input during the execution of the θIG-DUTY calculation processing, the crank interrupt processing is executed with priority.

First, in crank interrupt processing, the TDC signal.

Stage discrimination based on the crank angle signal, such as the energization stage (stage 2 in the example of FIG. 4) at which the count of the turn-on counter 17 should be started and the predetermined stage (stage 4 in the example of FIG. 4) at which the turn-off counter 18 should be started. , crank angle signal T2. occurrence time interval M
It performs control such as detection of E and i and activation of the turn-on counter 17 and turn-off counter 18.

On the other hand, in the θIG-DUTY calculation process, the advance angle control value θI
G, energization control value DUTY (coil energization time ratio % to TDC signal generation time interval), energization timing TDUT,
and calculates each data of ignition timing TIG.

To explain in more detail the calculation processing of each of the above data, the advance angle control value θIG is calculated based on the engine rotation speed Ne, the intake pipe absolute pressure PI
It is calculated from IA, engine water temperature Tw, etc. according to the following equation (1).

θIG=θMAP+θIGCR...(1) Here, O
MAp indicates the basic advance angle value, which is read from the map stored in ROMII based on the engine speed Ne and intake pipe absolute pressure PBA, and θIGCR is a correction variable value for the basic advance angle value, and is the engine cooling water temperature Tw. , read out from the table stored in the ROM II according to the intake air temperature TA, atmospheric pressure PA, etc.

The engine speed Ne used for calculating the OMAp value is given from the Me counter 24, and the value Me is determined by the crank angle signal T24 shown in FIG. 3(c) and FIG. 4(a).
The value MEM obtained by measuring each interval of each stage O to 5 with a clock pulse of a constant period (fixed clock pulse)
Additional fee Ms (=Mesa+MEgz+MEs) from 0 to 65
z+MEgi+MEs4+MEss).

Further, the energization control value DUTY is a function of the engine rotation speed Ne, and is read out from the table stored in the ROMII as described above, and is given by correcting this read value with the battery voltage.

Here, ignition is performed in the range from BTDCO to 60'', in other words, it is performed in either stage 4 or 5. Specifically, the data input to the turn-off counter 18 is from the rise of stage 4, The turn-off counter 18 starts counting, and when the count reaches O, the power supply to the secondary coil is cut off.If the input value to the turn-off counter 18 is TIG, then the TIG is the angle-hour conversion value. The value is determined from the advance angle control value θIG and the Me value determined as described above.

Similarly, the energization start time TDUT is also set to the advance angle control value ゛θI
This is a value obtained by converting the angle determined by the G1 energizer's value DUTY and Me value, and thereby any position between stages can be set.

Then, when the stage start point at which energization should be started for one ignition coil is detected, the turn-on counter 19 starts counting, and when the value corresponding to the TDUT value is counted down and the count reaches O, that is, the set energization starts. When the timing is reached, the flip-flop 19 is set and the primary coil of the ignition circuit 21 starts to be energized. and,
As described above, the flip-flop 19 is reset from the start of stage 4 to the ignition timing TIG.

The flip-flop circuit 19 is reset to the ignition circuit 2.
Outputs the energization off signal to 1, and at the timing of 1 energization OFF, 2
Next, a high voltage for ignition is generated in the coil, and the plug 22 is ignited at the specified advance angle position.

On the other hand, the first CPUI executes the FI calculation processing program. This FI calculation processing is performed at stage 3 in the crank interrupt processing on the second CPU Z side, that is, at BTDC90.
The execution is started upon receiving the trigger signal q which is output from the CPU 2 to the CPU I via the signal line 26 when the crank angle position of .degree. is detected. In this FI calculation process, the intake pipe absolute pressure signal PBA from the Pa transducer 5 and the throttle valve opening signal θTH are
1. Reading data such as detected value of 02 concentration in exhaust gas,
and reads the Me data counted by the Me counter 29, calculates the fuel injection time TOLI which will be described later, and controls the start-up of a counter for a predetermined cylinder in the counter circuit 7 simultaneously with the completion of the TOIJT calculation.

The above fuel injection time TOLIT is calculated by the following equation.

Togt=Ti
It is read out from the ROM 3 based on BA and the engine speed Ne. K1 and K2 are a correction coefficient and a correction variable that are respectively calculated according to engine parameter signals from the various sensors mentioned above, and depending on the engine operating state,
Various characteristics such as starting characteristics, exhaust gas characteristics, fuel consumption characteristics, engine acceleration characteristics, etc. are calculated based on a predetermined calculation formula so as to be optimal. The first CPUI is activated at the same time as the calculation of the fuel injection time T0IJT is completed as described above.

The data of this fuel injection time T0IJT is set in the counter of a predetermined cylinder in the counter circuit 7, and the counter is activated. The counter subtracts this data and supplies a valve opening time signal having a value corresponding to the fuel injection time data as a drive signal to the fuel injection valve 8 to control the fuel supply amount.

Next, data transfer such as engine operating parameter values via the data transfer signal lines 27 and 28 will be described. This data transfer is executed by a serial asynchronous method, and the above-mentioned crank interrupt processing executed by the second CPU 2, θ
The IG-DUTY calculation process and the FI calculation process executed by the first CPUI are executed when they are not being executed (this is referred to as "background"). First, when the first CPU is in the background where the FT calculation process is not being performed, the first CPU sends a transmission command 5END to the second CPU 2 via the communication line 28, as shown in FIG.
Send to. On the other hand, if the second CPLI 2 is not in the processing execution state such as crank interrupt processing but in the data reception enabled state, the second CPLI 2 sends a confirmation signal ACK indicating the data reception enabled state.
via the communication line 27 to the first CPUI. After responding, the first CPU 1 drives the shift register 33 with a clock pulse. With this drive, the shift register 33
teeth.

Every time a clock pulse is input, the data DATA containing the engine operating parameter values input in parallel through the latch circuit 32 is output one bit at a time while being shifted. 2 to CPU 2. The shift register 39 in the second CPU 2 serially latches the transferred data DATA one bit at a time using a clock pulse input from the signal line 40. Then, the latch circuit 38 is driven at the input timing of the last stop bit following this data DATA.
Data DATA is transferred from the shift register 39 to the latch circuit 3
8 bits are latched at the same time. The data DATA latched by the latch circuit 38 is written into the RAM 12 by a write process by the second CPU 2. Note that the second CPU
2 also includes a request command for requesting data transfer from the first CPUI. Then the second CPU
2, the RAM 12 has R on the first CPt1 side.
Similar to AM4, the latest values of each engine operating parameter are always written. When transferring 2 bytes of data, the second CPU 2 first transfers 1 byte as shown in FIG.
After receiving the byte of data DATA 1, it sends an acknowledgment signal ACK to the first CPUI, and then receives the subsequent 1 byte of data DATA 2. Note that when interrupt processing enters the CFIJ during such data transfer, the clock pulses to the shift registers 33 and 39 become non-input, the data transfer is interrupted, and priority is given to the interrupt processing. After this interrupt processing ends, data transfer is resumed.

Note that the fuel supply control in this invention may be any control such as fuel injection amount or injection timing, and the ignition control may be any control such as ignition timing 1 energization time.

(Effects of the Invention) As detailed above, according to the electronic control device for an internal combustion engine of the present invention, the first central processing unit controls fuel supply and the second central processing unit controls one ignition. a first detection means connected to the first central processing unit to detect a first engine operating parameter; and a first detection means connected to the second central processing unit to detect a second engine operating parameter. a second detection means; and a signal transfer means interposed between the first and second central processing units to mutually transfer detected values of the first engine operating parameter and the second engine operating parameter. and the first and second central processing units control the fuel supply and the ignition, respectively, based on the first and second engine operating parameters, so that each central processing unit has its own control target. It is sufficient to execute only the necessary arithmetic and control processing for each time, and therefore, the amount of processing that can be processed by the electronic control device increases and the overall processing time can be shortened.

As a result, even when controlling at high speeds where the time available for calculation processing is shortened, accurate and complex control can be achieved without the need for an expensive central processing unit with excellent calculation processing power. Effects can be obtained. In addition, input stage circuits such as A/D conversion circuits and waveform shaping circuits required for inputting engine operating parameters can be shared by the central processing unit, which prevents device complexity and facilitates maintenance. You can get the effect of becoming.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of an electronic control device for an internal combustion engine according to the present invention, and FIG. 2 is a block diagram showing the overall configuration of an electronic control device for an internal combustion engine according to the present invention, and FIG. 3 is a timing chart showing the pulse generation timing of the TDC signal, crank angle signal, etc., and FIG. 4 is a timing chart showing the timing to start energizing the ignition coil, the timing to stop energizing, etc. , FIGS. 5 and 6 are timing charts showing the transfer timing of data such as engine operating parameter values, and FIG. 7 is a block diagram showing the structure of one frame of data to be transferred. 1... first central processing unit (CPU), 2...
- Second central processing unit (CPU), 5... Intake pipe absolute pressure transducer, 8... Fuel injection valve, 1
6... Crank angle sensor, 23a-23d... Spark plug, 27.28... Communication line for data transfer, 31...
・Parallel-serial conversion circuit, 37...Series-parallel conversion circuit.

Claims (1)

[Claims] 1. Fuel supply means for supplying fuel to an internal combustion engine;
An electronic control device for an internal combustion engine comprising an ignition means for igniting an air-fuel mixture formed by supplied fuel, comprising: a first central processing unit that controls the fuel supply; and a first central processing unit that controls the ignition. a second central processing unit;
a first detection means connected to the first central processing unit to detect a first engine operating parameter; and a first detection means connected to the second central processing unit to detect a second engine operating parameter. Signal transfer means interposed between the second detection means and the first and second central processing units, and mutually transfers each detected value of the first engine operating parameter and the second engine operating parameter. and the first and second central processing units include the first and second central processing units.
and a second engine operating parameter, the electronic control device for an internal combustion engine is characterized in that the fuel supply and the ignition are controlled respectively. 2. Claim 1, wherein the first engine operating parameter includes at least engine temperature.
An electronic control device for an internal combustion engine according to paragraph 1. 3. The electronic control device for an internal combustion engine according to claim 1, wherein the second engine operating parameter includes at least a rotational position parameter of a crankshaft of the engine.