JPH03149338A - Electronic controller for vehicle - Google Patents

Abstract

PURPOSE:To execute serial data communication between plural microcomputers in synchronism with the rotation of an engine by making a data transmitting means transmit data and a data receiving means receive them with some phase difference kept between the above actions. CONSTITUTION:At least the first microcomputer 11 of plural computers is provided with a transmitting port 12A, from which data are transmitted by one bit in fixed order according to the rotational angle of a crankshaft. The second microcomputer 21 is provided with a receiving port 22B connected to the transmitting port 12A, and the data are received by one bit according to the rotational angle of the crankshaft from the port 22B. In addition to that, data transmitting and receiving performed by the microcomputers 11 and 21 respectively are executed with some phase difference kept between them. Thus, data communication can be executed between the microcomputers in synchronism with the rotation of an engine without providing special serial ports.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field) The present invention relates to a vehicle electronic control device, and in particular, in a vehicle electronic control device having a plurality of microcomputers, various types of control are directly performed between each microcomputer. The present invention relates to a vehicle electronic control device that performs data communication. (Prior Art) Engine ignition timing control, fuel injection control using an injector, etc. in automobiles, motorcycles, etc. (hereinafter referred to as vehicles) are performed using an electronic control device equipped with a microcomputer. Incidentally, in recent years, knocking control (vehicle control to prevent knocking) has been implemented, and various knocking detection methods have been proposed for this purpose, but this knocking detection requires relatively complicated processing. In order to do this, a microcomputer other than the one for performing ignition timing control, fuel injection control, etc. as described above may be used. Here, when each of these microcomputers performs calculations on various data using data output or calculated from the other microcomputer, data communication between the microcomputers is required. For this reason, conventionally, as shown in FIG. 18, a communication line 3 for transmitting and receiving 1-bit data is provided between a plurality of microcomputers (between the first and second microcomputers 1 and 2). Parallel communication can be performed by providing only the number of bits necessary for communication, or as shown in FIG. A general-purpose serial port 5 is provided at the end to perform serial communication using a reference clock within each microcomputer. (Problems to be Solved by the Invention) The above-described conventional technology had the following problems. (1) In the above-mentioned parallel communication, as the amount of data to be communicated increases, the number of communication lines increases accordingly, which increases the size and complexity of the configuration of the vehicle electronic control device and increases manufacturing costs. Furthermore, as the number of communication lines increases, the probability of failure of the vehicle electronic control device increases, and reliability decreases. (2) Serial communication requires a serial port for data transmission and reception, which increases the size of the vehicle electronic control device. Furthermore, when data is sent to and received from multiple destinations, additional serial ports or switching circuits are required, making the configuration of the vehicle electronic control device more complex and larger. Furthermore, since data communication is performed in synchronization with the microcomputer's clock, data communication cannot be performed in synchronization with the rotation of the engine. In other words, when controlling a vehicle, it is necessary to control various control devices (for example, ignition timing control, fuel injection control, knocking control, etc.) according to the engine rotation speed, but data communication that is synchronized with the engine rotation is not possible. Otherwise, the various control devices described above cannot be accurately controlled. The present invention was made to solve the above-mentioned problems, and its purpose is to transfer serial data between multiple microcomputers without the need for a special serial port and in synchronization with engine rotation. An object of the present invention is to provide a vehicle electronic control device that can communicate. (Means and Effects for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a transmission port for at least one of the plurality of microcomputers constituting the vehicle electronic control device. is provided, and transmits data one bit at a time from the transmission port in a predetermined order according to the rotation angle of the crankshaft, and transmits data to at least another microcomputer among the plurality of microcomputers to the transmission port. A receiving port is provided to be connected, and data is received bit by bit from the receiving port according to the rotation angle of the crankshaft,
Furthermore, the present invention is characterized in that data transmission by the above-mentioned microcomputer and data reception by the above-mentioned other microcomputer are performed with a phase difference. Moreover, in the buffer of the microcomputer mentioned above,
Further, all the data to be transmitted from the data transmitting means at predetermined timings are temporarily stored, and the data in the buffer is transmitted bit by bit to the transmitting port in accordance with the crankshaft rotation angle. It also has its own characteristics. As a result, data transmission corresponding to the crankshaft rotation angle can be performed by simply reading data from the buffer. (Example) The present invention will be described in detail below with reference to the drawings. FIG. 2 is a block diagram of one embodiment of the present invention. In FIG. 2, cylinder pulses, TDC pulses, and crank pulses extracted by a known method according to the engine rotation of the vehicle are input to the first microcomputer 11 via a waveform shaping circuit 31. Assuming that the engine is a 4-cylinder, 4-cycle engine, the cylinder pulse is generated when the crankshaft rotates 2 times (72
In this example, the TDC pulse outputs 1 pulse each time the piston of each cylinder reaches top dead center, that is, 4 pulses are output every 2 revolutions of the crankshaft. Six pulses are output every time one TDC pulse is output. These cylinder pulses and crank pulses are also input to a second microcomputer 21, which will be described later. The first microcomputer 11 performs main control of the vehicle, such as ignition timing control and fuel injection control, and includes a CPU 12 (hereinafter referred to as main CPU 12), a ROMSRAM, an input/output interface, etc. (none of which are shown in the figure). ). Pba sensor 32 that detects intake pipe internal negative pressure (absolute pressure) Pba; Tw sensor 3 that detects engine coolant temperature Tv
3. A Pa sensor 34 that detects atmospheric pressure Pa, a Th sensor 35 that detects throttle valve opening, and the like are connected to the first microcomputer 11 via an A/D converter 31. The first microcomputer 11 is also connected to a spark plug 43 via an igniter 41 and an ignition coil 42, and to an injector 45 via a driver 44. Ignition timing control and fuel injection control by the first microcomputer 11 may be performed using known methods. Fuel injection control is, for example, disclosed in Japanese Patent Publication No. 62-862
It is described in Publication No. 5. Further, there are multiple types of cams (not shown) for driving the intake and exhaust valves of the engine, and one of them is selected depending on, for example, the rotational speed and load of the engine. This signal for cam selection (hereinafter referred to as valve timing V
/T) uses the rotational speed of the engine and the engine load state signal to control the first microcomputer 11.
It is calculated by This valve timing V/T is output to a driver 46, and a solenoid 47 for selecting the cam is driven. The second microcomputer 21 detects the knob king of the engine, and similarly to the first microcomputer 11, the second microcomputer 21 has a CPU 22 (hereinafter referred to as a knock CP).
U22''), ROMSRAM, input/output interface, etc. (none of which are shown).A knock sensor installed in the engine cylinder head (
The pressure sensor) 38 is connected to the second microcomputer 21 via a waveform shaping circuit 39. Now, as mentioned above, the second microcomputer 21 detects knocking, but in order to detect this knocking, not only the output signal of the knock sensor 38 but also the Pba
The output signals of the sensor 32 and Tv sensor 33 as well as the valve timing V/T are also required. Output signals of the Pba sensor 32 and Tw sensor 33,
Further, the valve timing V/T is directly transmitted from the general-purpose transmission port 12A of the main CPU 12 to the general-purpose reception port 22B of the knock CPU 22 by a method described later. The first microcomputer 11 also uses information indicating whether or not knocking is occurring (hereinafter referred to as a knock flag) determined by the second microcomputer 21, and whether the knock sensor 38 is operating normally. Failsafe signal (hereinafter referred to as F)
/S flag) to prevent ignition timing control (hereinafter referred to as knock control) to prevent knocking.
I do. This knock control retards the ignition timing when the engine is knocking, and returns the ignition timing to its original state (advances the ignition timing) when the knocking stops. Such a knock control method is described in, for example, Japanese Patent Laid-Open No. 63-29061. The knock flag and F/S flag are directly transmitted from the general-purpose transmission port 22A of the knock CPU 22 to the general-purpose reception port 12B of the main CPU 12 by a method described later. Note that, in FIG. 2, illustration of a battery R (battery) that supplies power to each component shown in the figure is omitted. Now, among the operations of the vehicle electronic control device having such a configuration, a method of data communication between the main CPU 12 and the knock CPU 22 will be described in detail below. Knock CPU from transmission port 12A of main CPU 12
The data sent to 22 is: ■Valve timing V/T: L/H” information (1 bit) ■Intake pipe negative pressure Pba: Zone information 4 stages (2 bits) ■Cooling water temperature Tν: Zone information The data is 8 stages (3 bits), totaling 6 bits. Also, the data sent from the transmission port 22A of the knock CPU 22 to the main CPU 12 is: ■Knock flag: present/absent information (1 bit)■ F/S flag:
It is a total of 2 bits of data including presence/absence information (1 bit). First, a data communication method for transmitting data from the main CPU 12 to the knock CPU 22 will be described. FIG. 3 is a time chart showing the main operations when transmitting data from the main CPU 12 to the knock CPU 22, FIGS. 4 and 5 are flow charts showing the main processing operations performed by the main CPU 12 in this case, and similarly
The figure is a flowchart showing the main processing operations performed by the knock CPU 22 in this case. Further, FIGS. 6 and 8 are flowcharts showing background processing executed by the main CPU 12 and the knock CPU 22. Note that R xbuf shown in the lower part of FIG. 3 indicates an 8-bit buffer (register) in the second microcomputer 21, which will be described later regarding step S34 in FIG. Furthermore, as shown in Fig. 3, the generation stage of the crank pulse that occurs immediately after the rising edge of the TDC pulse is referred to as the 0th stage, and thereafter, the generation stage of the crank pulse that occurs immediately after the rise of the TDC pulse is the 0th stage. The stage number is incremented. That is, the stage numbers are from O to 5. In other words, this stage indicates the crankshaft rotation angle of the engine. Crank processing (processing synchronized with crank pulses) performed by the main CPU 12 is performed by an interrupt signal generated at the start of each stage. In Fig. 4, the main CPU 1 performs the crank processing.
Only the main processing when data is transmitted from No. 2 to the knock CPU 22 is shown. Further, immediately after the cranking process is completed in the 0th stage, the ignition timing/fuel amount calculation process shown in FIG. 5 is performed. If the first stage is reached before this ignition timing/fuel melon calculation processing is completed, the crank processing is performed preferentially by an interrupt, as shown in Fig. 3, and the crank processing is completed. After that, the continuation of the ignition timing/fuel amount calculation process is executed again. Although not shown, when the engine is in a high rotational speed state, the ignition timing/fuel amount calculation process may be continued in the second, third, and so on stages. Further, in FIG. 5, only the main processing in the case of data communication from the main CPU 12 to the knock CPU 22 among the ignition timing/fuel amount calculation processing is shown. Further, the main CPU 12 performs the background processing shown in FIG. 6 when the load of calculations and the like is lightened. The cranking process performed by the knock CPU 22 is also performed by an interrupt signal generated at the start of each stage. FIG. 7 shows that the main CPU 1 performs this cranking process.
Only the main processing when data is transmitted from No. 2 to the knock CPU 22 is shown. Further, the knock CPU 22 performs the background processing shown in FIG. 8 when the load of calculations and the like is lightened. First, the operation of the main CPU 12 will be explained. In the ignition timing/fuel amount calculation process shown in FIG. 5, first in step Sll, the intake pipe negative pressure Pba signal output from the pbB sensor 32 is read. In step S12, the read Pba is set to 4
Determine which of the zones (zones) you want to enter. That is, in this process, the read Pba is converted into 2-bit digital data. This converted 2-bit data is sent to an 8-bit buffer (register) Txbuf in the first microcomputer 11.
(Pb
a data is indicated by symbol X). In step S13, the region (zone) of the cooling water temperature Tv determined and stored in step S22 in FIG. 6, which will be described later, is read out. This cooling water temperature zone is divided into 8 stages as described above, and the TV data is 3 bits. Furthermore, in step S22, the TV
The data is stored in the third to fifth bits of the 8-bit register (see FIG. 9, in which TV data is indicated by the symbol Y). In step S14, the contents of the 8-bit register read in step S13 are transferred to the buffer T x
buf (see FIG. 9C). In step S15, the valve timing V/T (
1 bit data) is read, and step 81
6, the data is stored in the 0th buffer Txbuf.
It is stored in the bit-th bit (see figure 9, in the same figure,
Valve timing V/T data is indicated by numeral 2. ) In the following explanation, the buffer T x
6-bit data (Pbl
, Tw and V/T) are called frame data. In step 81g, calculations of ignition timing (angle), fuel injection amount, etc., engine load determination, valve timing V/T setting, etc. are performed. After that, other processing (not shown) is performed, and the processing ends. Next, in the cranking process shown in Figure 4, first in step S1, it is determined what stage the stage in question is, that is, the stage number. and,
In step S2, various processes are performed according to each stage (for example, angle-time conversion of the ignition timing calculated in FIG. 5 described above, timer start for ignition, etc.)
is executed. Next, in step S5, the determined stage number is set to n. In step S6, step 3 in FIG.
16, the n-th bit data of the frame data configured in the buffer T xbuf is sent to the transmission port 1.
Output to 2A. That is, in the ignition timing/fuel amount calculation process shown in No. 3-, if the process shown in step S16 is completed at the time point shown by the symbol A, the buffer T xbuf synthesized in step 316 is
The first and second bit data (Pba) of the buffer Txbuf are output to the transmission port 12A in the first and second stages, respectively, and the third to fifth bit data (Tw) of the buffer T , respectively, are output at the third to fifth stages, and the 0th bit data (valve timing V/T) of the buffer Txbur is output at the O-th stage. After that, other processing (not shown) is performed, and the processing ends. In the background processing of FIG. 6, step S
At step 21, the output signal of the Tw sensor 33 is read. Then, in step S22, the read Tv
It is determined which of eight zones it falls into. That is, in this process, TV is converted into 3-bit digital data. This converted 3-bit data is stored in the 3rd to 5th bits of the 8-bit register (0th pitle 7th bit) in the first microcomputer 11, as described above in step S13. (See Figure 9-8). Next, the operation of the knock CPU 22 will be explained. In the cranking process shown in FIG. 7, first in step S31, the stage number is determined. Then, in step S32, various processes (for example, knocking determination, etc.) according to each stage are executed. In step S33, the determined stage number is set to n. Following this step S33, the process of step S34 is performed, but the process of this step S34 is completed by the time the process of step S6 of the main CPU 12 shown in FIG. 4 is started. There is. That is, the cranking process executed by the main CPU 12 shown in FIG. 4, and the knocking CPU shown in FIG.
The cranking process executed by 22 is executed at the same time as the start of each stage, but the process of step S34 in FIG.
The process of step S6 in the figure is performed some time after the start of the cranking process (that is, after the process of step S2 and the processes of steps S3, 34, etc. described later with reference to FIG. 11 have been executed). As will be described later, the process of step S34 is a process of reading data generated at the transmission port 12A into the knock CPU 22, but due to the difference in the processes of steps S34 and S6 described above, in other words, the position of steps S34 and S6 is Due to the phase difference, as shown in FIG. 3, data generated at the transmission port 12A is read into the knock CPU 22 immediately after the start of each stage, and thereafter
The data occurring in 2A is updated. In step S34, the data generated at the transmission port 12A of the main CPU 12 is transferred to the 8-bit buffer Rχbuf (
The (n-2)th bit of the (Oth bit to seventh bit) is read and stored. That is, as shown in FIG.
The data of P bas T v and valve timing V/T generated at the transmission port 12A of the main CPU 12 are stored in the Oth to fifth bits of f. After that, other processing (not shown) is performed, and the processing ends. In the background processing of FIG.
At 41, the second microcomputer 21 determines whether the knock sensor 38 is functioning normally.
F/S flag is generated. Next, a data communication method for transmitting data from the knock CPU 22 to the main CPU 12 will be explained. FIG. 10 is a time chart showing the main operations when data is transmitted from the knock CPU 22 to the main CPU 12, and FIGS.
Similarly, FIG. 13 is a flowchart showing the main processing operations performed by the knock CPU 22 in this case. Of the crank processing and ignition timing/fuel amount calculation processing performed by the main CPU 12, only the main processing when transmitting data from the knock CPU 22 to the main CPU 12 is shown in FIGS. 11 and 12. Also, in FIG. 13, among the crank processing performed by the knock CPU 22, the main CPU is
Only the main processing when transmitting data to U12 is shown. First, in the cranking process of FIG. 13 executed by the knock CPU 22, after stage determination etc. are performed (after step 831 etc. of FIG. 7), in step S35,
It is determined whether the stage in question is the Oth stage. If it is the O-th stage, the knock flag calculated by the second microcomputer 21 is outputted to the transmission port 22A of the knock CPU 22 in step 836. If it is determined in step S35 that the stage is not the O-th stage, then it is determined in step S37 whether or not the stage is the third stage. If it is the third stage, in step 53B,
The F/S flag is output to the knock CPU 22Q transmission port 22A. After completing step 836 or 83g, or if the stage is neither the Oth stage nor the third stage, other processing (not shown) is then performed, and the processing ends. Next, in the cranking process shown in FIG. 11 executed by the main CPU 12, after a predetermined stage determination (step Sl in FIG. 4), etc. is performed, in step S3,
It is determined whether the stage in question is the fourth stage. If it is the fourth stage, in step S4, data generated at the reception port 12B of the main CPU 12 (that is, data generated at the transmission port 22A of the knock CPU 22) is read as an F/S flag. After step S4 is completed, or in step S3, if the stage is not the fourth stage, then other processes not shown are performed, and the process ends. In the ignition timing/fuel amount calculation process shown in FIG. 12 executed by the main CPU 12, in step SIT, the data generated at the reception port 12B of the main CPU 12 (that is, the data generated at the transmission port 22A of the knock CPU 22) is converted into a knock signal. Read as a flag. The process of step S17 is performed after the synthesis of the buffers Txbu is completed (after the process of step 816 in FIG. 5 is completed). In this way, the knock flag and F/S flag calculated by the second microcomputer 21 are transferred to the first microcomputer 11. Now, in this way, data is transmitted from the first microcomputer 11 to the second microcomputer 21, and conversely, data is also transmitted from the second microcomputer 21 to the first microcomputer 11. . And, this data overconfidence changes for each stage, that is, depending on the engine rotation (crankshaft rotation angle).
It will be done. By the way, data transmission from the first microcomputer 11 to the second microcomputer 21 and data transmission from the second microcomputer 21 to the first microcomputer 11 are performed using different time charts and flowcharts. However, these communications are performed simultaneously. That is, the main CP shown in FIGS. 4 and 11
Crank processing executed by U12, Fig. 5 and Fig. 1
The ignition timing/fuel amount calculation process executed by the main CPU 12 shown in FIG. 2 and the crank process executed by the knock CPU 22 shown in FIGS. 7 and 13 are the same crank process program, Ignition timing/
It is stored in each microcomputer 11 and 12 as a fuel amount calculation processing program. FIG. 14 is a time chart of an embodiment of the present invention,
This is a composite of the time charts shown in FIG. 3 and FIG. 10 mentioned above. Further, FIG. 15 is a flowchart showing the cranking process executed by the main CPU 12, and is a flow chart showing the cranking process executed by the main CPU 12.
This is a composite of the flowcharts shown in FIG. 1 and FIG. Similarly, FIG. 16 is a flowchart showing the ignition timing/fuel amount calculation process executed by the main CPU 12.
FIG. 1 is a flowchart showing the cranking process executed by the knock CPU 22, and is a composite of the flowcharts shown in FIGS. 5 and 12, and FIGS. 7 and 13, respectively, shown above. In FIGS. 14 to 1F, the same reference numerals used to create (synthesize) each figure represent the same or equivalent parts, so the explanation thereof will be omitted. Note that the process of step 816 shown in FIG. 16 (FIG. 5) needs to be executed during the O-th stage even when the engine speed is high, and the process of step 816 shown in FIG. 16 (FIG. 12) The process of S17 needs to be executed between the 0th stage and the 2nd stage even when the engine speed is high. The process of step S17 may be executed during the cranking process of the first stage or the second stage, or after the knock flag is output to the transmission port 22A in the O-th stage, the process of the cranking process of the stage It may be done in Furthermore, steps S3 and S4 in FIG. 15 (FIG. 11)
As explained in , F/
Reading of the S flag is assumed to be carried out in the fourth stage, or may be carried out in the third stage after the F/S flag is output to the transmission port 22A, or may be carried out in the fifth stage.
It may be a stage. Now, as shown in Figures 5 and 16, the main C
In the ignition timing/fuel amount calculation process executed by the PU 12, reading of Pba and zone discrimination (A/D conversion), reading of Tw read and zone discriminated in background processing, and reading of valve timing V/T are performed. The data is used to configure 6-bit frame data in the buffer Txbuf, so the main CPU 1 executed in each stage
In the cranking process in step 2 (Figures 4 and 15),
Simply data bit by bit from buffer Txbur
2 All you have to do is read out F -. As a result, the load on the cranking process executed by the main CPU 12 is reduced, and the processing time does not become too long, so that even if the engine speed becomes high, the engine can be well controlled. FIG. 1 is a functional block diagram of an embodiment of the present invention. In FIG. 1, the same reference numerals as in FIG. 2 represent the same or equivalent parts. In FIG. 1, the left side of the broken line shows the configuration of the first microcomputer 11, and the right side of the broken line shows the configuration of the second microcomputer 21. First, on the first microcomputer 11 side, a cylinder pulse, a TDc pulse, and a crank pulse are input to the stage discrimination means 51 and the engine rotation speed discrimination means 52. The stage discrimination means 51 discriminates the stage number, and the engine rotation speed discrimination means 52 discriminates the engine rotation speed. The fuel injection control means 58 controls the fuel injected from the injector 45 by a known appropriate method using the engine rotational speed signal and the output signals of the Pba sensor 32, Tv sensor 33, Pa sensor 34, Th sensor 35, etc. calculates the injection amount, fuel injection timing, etc. The output signal of this fuel injection control means 58 is manually inputted to the driver 44,
This drives the injector 45. The ignition timing control means 59 receives the engine rotation speed signal and Th
The ignition timing is calculated using the output signal of the sensor 35 and the like. The output signal of this ignition timing control means 59 is manually input to the igniter 41. This igniter 41 is connected to a spark plug 43 via an ignition coil 42. The load determining means 54 detects the load of the engine using the output signal of the Pba sensor 32 and/or the Th sensor 35, or other signals by a known method. The V/T calculating means 53 calculates the valve timing V/T using the engine rotation speed signal and the engine load signal (output signal of the load determining means 54). This calculated valve timing V/T is input to the driver 46,
As a result, the plurality of cam selection solenoids 47 for driving the intake and exhaust valves are driven. Zone determining means 55 and 56 determine which of the four-stage and eight-stage zones the output signals of the pbH sensor 32 and the Tv sensor 33 belong to, respectively, and convert them into 2-bit and 3-bit signals, respectively. do. Then, the determined and converted zone information is output to the buffer Txbuf57 at the 0th stage. Similarly, the output signal of the V/T calculating means 53, that is, the valve timing V/T (1-bit data) is also output to the buffer Txbuf 57 in the O-th stage. In the 0th stage with the buffer Txbul57
Within this time, 6-bit frame data as shown in Figure 9 is completed. The frame data in the buffer Txbuf 57 is output to the transmission port 12A one bit at each stage. Specifically, as shown in FIG. 3 (or FIG. 14), 2-bit data of Pba is used in the first and second stages, 3-bit data of Tv is used in the third to fifth stages, and In stage 0, 1-bit data of pulp timing V/T is sent to each transmission port 1.
Output to 2A. On the other hand, on the second microcomputer 21 side, the cylinder pulse and the crank pulse are detected by the stage discriminating means 8.
1 is man-powered. This stage discrimination means 81 discriminates the stage number similarly to the stage discrimination means 51 described above. The buffer Rxbuf 82 takes in data transferred from the transmission port 12A to the reception port 22B, one bit at each stage. For details, see Figure 3 (Figure 14)
As shown in , in the second and third stages P
The 2-bit data of ba, the 3-bit data of Tv in the 4th, 5th and O-th stages, and the 1-bit data of valve timing V/T in the 1st stage are respectively stored in the O-th to O-th buffers Ijxbuf82. Fifth
Incorporated into the bit. When data is taken into the buffer Rxbuf82,
The data is transferred to data determining means 83, and the content of the data is determined. The contents of this data (that is, each data of PbalTw and valve timing V/T) are input to the knocking determination means 84. The knocking determination means 84 determines whether or not knocking occurs using the respective data and the signal output from the knock sensor 38, and outputs a knock flag. This knock flag, as shown in FIG. 10 (FIG. 14),
At the O-th stage, the signal is output to the transmission port 22A. The F/S determining means 85 determines whether the knock sensor 38 is normal or not, and generates an F/S flag. This F/S flag is output to 22 transmission ports in the third stage, as shown in FIG. 10 (FIG. 14). Returning to the first microcomputer 11 side again, in the O-th stage, the transmission port 22A is connected to the reception port 12.
The data transferred to B is taken into the knocking control means 60 as a knocking flag. Furthermore, in the fourth stage, the data transferred from the transmission port 22A to the reception port 12B is taken into the knocking control means 60 as an F/S flag. The knocking control means 60 corrects the ignition timing data output from the ignition timing control means 59 to the igniter 41 in accordance with the knock flag. Now, in the above explanation, it was assumed that the first microcomputer 11, which performs the main control of the vehicle, communicates with the second microcomputer 21, which determines knocking. , when performing traction control to suppress vehicle slippage during acceleration or other controls using a microcomputer different from the first microcomputer 11, and when communicating between the microcomputer and the first microcomputer 11; It goes without saying that the present invention is also applicable. Further, the present invention can be applied even if there are three or more microcomputers that perform data communication. Furthermore, when transmitting data from the first microcomputer 11 to the second microcomputer 21, the main CPU 12 performs ignition timing/fuel amount calculation processing.
The buffer T
Create frame data in f, and convert the frame data into
In the cranking process of the main CPU 12 performed for each stage, the second microcomputer 21
However, if the processing time delay of the crank processing is allowed, the creation of frame data in the buffer Txbul can be omitted, and each data The data may be read out and A/D converted, and then transmitted. That is, for example, regarding the transmission of Pba, the processes of steps Sll and S12 in FIG. 5 (FIG. 16) are performed by the first stage crank process of the main CPU 12, and A
/D converted 2-bit Pba data is transmitted in the first
The second stage cranking process may be performed bit by bit. Conversely, when transmitting data from the second microcomputer 21 to the first microcomputer 11,
Frame data similar to the above-mentioned frame data is once formed in the buffer of the second microcomputer 21, and then, in the cranking process executed by the knock CPU 22 at each stage, the data in the buffer is converted into 1-bit data. Of course, the output may be made to one microcomputer 11. (Effects of the Invention) As is clear from the above description, according to the present invention, the following effects are achieved. (1) According to the electronic control device for a vehicle according to the first aspect, data communication can be performed between a plurality of microcomputers in synchronization with engine rotation without requiring a special serial port. (2) According to the electronic control device for a vehicle according to claim 2, since it is only necessary to transmit data according to the crankshaft rotation angle or read data from the buffer, Further, the time required for data processing (crank processing) other than data processing for data transmission is not delayed. As a result, even when the engine speed increases, various controls for vehicle control are not delayed and can be performed satisfactorily.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram of an embodiment of the present invention. FIG. 2 is a block diagram of one embodiment of the present invention. FIG. 3 is a time chart showing the main operations when transmitting data from the main CPU 12 to the knock CPU 22. FIG. 4 and FIG. 5 show the processing operations performed by the main CPU 12 from the main CPU 12 to the knock CPU 2.
2 is a flowchart illustrating main processing operations when transmitting data to No. 2. FIG. FIG. 6 is a flowchart showing background processing performed by the main CPU 12. FIG. 7 shows data transmission from the main CPU 12 to the knock CPU 22, which is one of the processing operations performed by the knock CPU 22. 12 is a flowchart showing main processing operations in the case of T. FIG. 8 is a flowchart showing background processing performed by the knock CPU 22. FIG. 9 is a diagram for explaining the 8-bit buffer Txbuf and how data is structured within the buffer. FIG. 10 is a time chart showing the main operations when transmitting data from the knock CPU 22 to the main CPU 12. FIG. 11 and FIG. 12 show the processing operations from the knock CPU 22 to the main CPU among the processing operations performed by the main CPU 12.
It is a flowchart which shows the main processing operation when transmitting data to U12. FIG. 13 is a flowchart showing the main processing operations when transmitting data from the knock CPU 22 to the main CPU 12, among the processing operations performed by the knock CPU 22. FIG. 14 is a time chart of one embodiment of the present invention. FIG. 15 is a flowchart showing the cranking process executed by the main CPU 12. FIG. 16 is a flowchart showing the ignition timing/fuel amount calculation process executed by the main CPU 12. FIG. 11 is a flowchart showing the cranking process executed by the knock CPU 22. FIGS. 18 and 19 are diagrams for explaining a conventional data communication method performed between a plurality of microcomputers. DESCRIPTION OF SYMBOLS 11... First microcomputer, 12... Main CPU, 12A... Transmission port, 12B... Receiving port, 21... Second microcomputer, 22...
・Crank CPU, 22A...Sending port, 22B
--...Reception port, 32-Pba sensor, 33...T
w sensor, 38... crank sensor, 43... spark plug, 45...-injector, 47... turenoid,
51... Stage discrimination means, 52... Engine speed discrimination means, 53... V/T calculation means, 54... Load discrimination means, 55.5 Low... Zone discrimination means, 57.
... Buffer Txbuf, 5 B... Fuel injection control means, 59... Ignition timing control means, 60... Picking control means, 81... Stage discrimination means, 82--...
Buffer Rxbufs 83-data discrimination means, 84
...-knocking discrimination means, 85...F/S discrimination means

Claims (2)

[Claims] (1) A vehicle electronic control device comprising a plurality of microcomputers that perform various processes according to the rotation angle of a crankshaft, and performing serial data communication between the microcomputers according to the rotation angle. At least one of the microcomputers includes a transmission port and data transmission means for transmitting data one bit at a time in a predetermined order to the transmission port in accordance with a crankshaft rotation angle, At least another of the microcomputers includes a reception port connected to the transmission port, and data reception means for receiving data bit by bit from the reception port in accordance with a crankshaft rotation angle, An electronic control device for a vehicle, wherein the data transmitting means and the data receiving means transmit and receive data with a phase difference. (2) The first microcomputer further temporarily stores all data to be transmitted from the data transmitting means in a buffer, and the data transmitting means transmits the data in the buffer according to the crankshaft rotation angle. 2. The vehicle electronic control device according to claim 1, wherein the vehicular electronic control device transmits one bit at a time to the transmission port.