JPH05216776A - Control unit for vehicle - Google Patents

Abstract

PURPOSE:To improve the reliability of data by judging the quality of data stored in an EEPROM. CONSTITUTION:The EEPROM of 256 bytes is used, the data area is divided into four areas, SUM areas 1-4 and SUM write check areas SUMF 1-4 are provided in the respective data areas 1-4, the low-order two bytes of the total added value of data excepting for the SUM areas in the respective areas are written and stored in the SUM areas 1-4, and data showing the execution of SUM write are written and stored in the SUM write check area SUMF 1-4. Even when any area is judged as NG, for example, the other areas can be used as storage areas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control unit mounted on an automobile, which uses a microcomputer and incorporates an EEPROM.

[0002]

2. Description of the Related Art A SUM that does not divide an area is used for checking.

[0003]

The EEPROM is a readable / writable memory that does not use a power source for holding data, but has a limitation in compensation of the number of times of writing. Therefore, it is necessary to judge the quality of the stored data.

[0004]

[Means for Solving the Problems] The data of the EEPROM is checked by a sum for each divided area.

[0005]

[Function] The data held in the EEPROM can be stored for a long period of time.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an engine control system for a 4-cycle engine. In a 4-cycle engine,
Air taken into the engine (hereinafter referred to as intake air volume)
Passes through the air cleaner 18 and the throttle valve 1 in the air supply pipe 30.
6, the intake air amount is limited, the fuel is mixed with the fuel injected and supplied from the injector 8, and the intake valve 19 and the cylinder head 2 are lowered during the intake stroke in which the piston 20 descends.
It is sucked into the cylinder through the gap with the cylinder 9. The intake / mixed air / fuel is transferred to the piston 20 during the compression stroke.
Is compressed by the rise of the ignition plug 15 and ignited by the ignition plug 15 to explode (combust) and push down the piston 20 (expansion stroke). The exhaust gas in the cylinder after combustion passes through the gap between the exhaust valve 21 and the cylinder head 29, which have dropped during the exhaust stroke, is guided to the exhaust pipe 31, and the harmful components in the exhaust gas are removed by the catalyst 22 and then the atmosphere. Is discharged to.

2 is the amount of air taken into the engine (hereinafter,
An air flow meter for converting an intake air amount) into an electric signal, 3 is a water temperature sensor for outputting a signal according to the cooling water temperature of the engine, and 4 is a crank angle for outputting a signal when the crank angle of the engine indicates a predetermined position. The sensor 5 is a throttle sensor 5 that outputs a signal according to the opening degree of the throttle valve 19 that adjusts the intake air amount. An oxygen concentration sensor (hereinafter referred to as an O ₂ sensor) 6 outputs a low voltage (LOW signal) when the oxygen concentration is high and a high voltage (HI signal) when the oxygen concentration is low. Combustion in the cylinder depends on the air-fuel ratio (air AI
Mass ratio of R and fuel FUEL (hereinafter referred to as A / F) is 14.7.
In the vicinity, fuel and air burn best, and when the A / F is smaller than this, oxygen is insufficient, and when it is larger than this, oxygen is excessive. Since the output of the O ₂ sensor changes depending on the oxygen concentration, it is possible to know the air-fuel ratio during actual combustion. A battery 7 supplies power to the sensor group, the actuator group, and the control unit.

Besides this, the starter SW 23 and the air conditioner S
W24, N / L SW (gear neutral / non-neutral detection and clutch ON / OFF state detection) 2
5, power steering SW 26, electric load SW (ON / OFF of headlights and radiator fan) 27, vehicle speed sensor 2
8, etc. are connected to the control unit 1.

Reference numeral 1 denotes a control unit, which detects an operating state of the engine based on signals from the above-mentioned sensor group, SW group, etc., and sends a fuel injection signal to the injector 8 based on a predetermined procedure based on these information. The engine is comfortably controlled by outputting an ignition signal to the ignition device 13 and an idle speed control signal to the ISC valve 12.

The fuel in the tank 11 is pressurized by the pump 10 and sent to the injector 8 and the pressure regulator 9. The pressure regulator 9 supplies fuel pressure to the injector 8 (hereinafter referred to as fuel pressure).
Is adjusted (adjusted) so that is a predetermined value. Injector 8
Is opened (ON) / closed (OFF) by a (driving) signal from the control unit 1 to supply a predetermined fuel to the engine.

The ignition coil 13 turns on / off two coils, a primary coil and a secondary coil, and energization to the primary coil.
The power switch for FF is built in. The primary coil is connected to the control unit 1 via a power switch. The secondary coil is connected to a spark plug 15 of each cylinder of the engine via a distributor 14 that distributes an ignition signal.
Also, the secondary coil has a structure in which the number of turns is larger than that of the primary coil, and when the power switch turns ON / OFF the primary coil, a high voltage is generated in the secondary coil and the secondary coil is connected. Sparks fly to the spark plug 15 that is being ignited, so that the air / fuel in the cylinder is ignited (combusted).

An idle speed control valve (hereinafter referred to as an ISC valve) 12 changes the opening area of a passage bypassing the throttle valve 9 that limits the intake air amount according to a signal from the control unit 1.

In the fuel injection control for adjusting the amount of fuel supplied to the engine, the control unit calculates the basic fuel injection amount required for the engine from the measured intake air amount.
Further, the engine temperature state detected by the water temperature sensor 3 (warm air-after warm-up to high water temperature), the engine speed calculated from the crank angle sensor, the throttle sensor 5, and the acceleration / deceleration of the engine detected from each SW group state. The basic fuel injection amount is increased / decreased and corrected according to the engine operating conditions such as (amount of change in signal within a predetermined time), idle (throttle valve is fully closed), load fluctuation, etc., and an injection pulse is output to the injector 8. This brings the engine into an appropriate operating state according to the load and rotation.

Further, the fuel injection amount is increased by the A / F detected from the signal of the O ₂ sensor 6 when the A / F is lean (the fuel is thin), and the A / F is rich (the fuel is rich).
In the state, the A / F is always controlled to be close to the theoretical air-fuel ratio of 14.7 by adjusting so as to reduce the amount, and the harmful components in the exhaust gas are suppressed.

In the ignition control for controlling the ignition timing of the engine and the energization time to the ignition coil, the control unit 1 controls the engine rotation speed, the intake air amount, the engine water temperature, the operating state of the engine recognized from each SW group state and the operating state of the engine. The optimum ignition timing (crank angle position) is calculated and determined according to the engine temperature condition. Further, the energization time for obtaining the energy required for ignition is calculated from the voltage state of the battery 7 and the operating state of the engine. Then, the energization to the ignition coil 13 is turned on / off at the optimum crank angle position based on the crank angle position obtained based on the signal of the crank angle sensor 4, and ignition is performed at the optimum timing. This brings the engine into an appropriate operating state according to the load and rotation.

In the ISC control for controlling the amount of air bypassed from the throttle valve, the control unit 1 observes the fluctuation of the engine speed when the engine is idle (throttle valve 9 is fully closed).
By controlling the ISC valve 12 so that the intake air amount is decreased when the rotation speed is increased and is increased when the rotation speed is decreased, the idle rotation fluctuation is suppressed, or the ISC valve 13 is increased so that the intake air amount is increased when the vehicle is suddenly decelerated. By controlling, the deceleration shock caused by the sudden change (decrease) in the intake air amount is suppressed, and the sudden fluctuation of the engine is mitigated.

FIG. 2 is a block diagram of the control unit 1. The control unit 1 performs processing such as signal conversion and noise removal of a digital signal in which the signal levels of the microcomputer 37 that performs signal processing and calculation, the crank angle sensor 4 of the sensor group 32, the vehicle speed sensor 28, SWs, etc. are discrete. The digital signal input circuit 35, the analog signal input circuit 36 for removing noise of the analog signal whose signal level of the water temperature sensor 3, the throttle sensor 5, etc. continuously changes, the output signal of the microcomputer 37, the external actuator 45. It is composed of an output circuit 44 for converting into a driving signal. The microcomputer 37 includes a CPU 43 for performing calculations, a ROM 42 for storing programs and control data, and an RA for storing temporary data during operation.
M41, a counter 40 for counting, a digital signal is input, and a control signal is output to the output circuit according to the calculation result.
/ O38, A / for converting analog signals to digital signals
An electrically writable EPROM (hereinafter referred to as "EEPROM") 46, which is composed of the D converter 39, is connected to the microcomputer (may be inside). Data that needs to be rewritten, such as learned memory values, destinations, and adjustment data, and that must be retained even when the control unit is powered off is stored in the EEPROM 46. CPU
43 is a program of the ROM 42 to generate a desired output signal from the sensor input signal by using a counter or the like, and I / O 3
8 to the output circuit 44. The output circuit 44 converts an output signal from the microcomputer 37 into an output capable of operating an actuator 45 such as an injector or an ignition and outputs the output to the corresponding actuator. The actuator operates according to the output signal to control the engine.

FIG. 3 shows the area division and structure of the internal data of the EEPROM of the present invention. In this example, 256 bytes of EEPROM
Is used to divide this data area into four. SUM areas 1 to 4 and SU are included in the respective data areas 1 to 4.
M write check areas SUMF1 to 4 are provided, and the lower 2 bytes of the sum total value of the data of each area other than the SUM area are SUM1 to 4 and the data indicating that the SUM write is performed is the SUM write check area. It is written and stored in SUMF1 to SUMF4. In the present invention, by dividing the inside of the EEPROM into four, for example, area 1
Even if is judged to be NG, the other area can be used as a storage area, so that the EEPROM can be effectively used.

Below, SUM writing to EEPROM, SUM
Sequence of calculation and data check will be described with reference to FIG. When the control unit is activated, first, the microcomputer is initialized (initialized) by the ROM program according to a predetermined procedure.
Next, the microcomputer checks the SUM write check area in the area 1 of the EEPROM at 101, and
If the UM is written, the SUM of the data area 1 of the area 1 is calculated in 102, the SUM data stored in the SUM area is checked in 103, and the result of the check is 0.
You can judge K and NG. Here, for example, when the collation determination is NG, whether or not the area 1 can be used is checked by writing. The data to be written and collated is arbitrary, but $ 00 (all 1-byte data is 1) is written in all areas 1 judged as NG in 104, the SUM of area 1 is calculated in 105, and $ 0 is calculated in 106.
Match with 0. Here, if OK, further, at 107, $ FF is added to all area 1 (all 1-byte data is 1).
Is written, 108 is used to calculate the SUM, and 109 is, for example, in area 1 of FIG.
Match with FC0. If the result of 106 or 103 is NG, the corresponding area of the EEPROM is determined to be NG and that area is not used. In the case of OK, the memory is permitted to restart at 110, and the routine proceeds to the SUM check routine of the next area. Area 1 in the EEPROM is checked as described above. If the SUM is not written in the EEPROM in 101, the SUM of area 1 is calculated in 112, and SUM1 is calculated in 113.
The SUM value is written in, the SUMF1 is set in 114, and the routine proceeds to the next area check routine. With the above, checking of one divided area is completed.
This is done for the number of divisions, and the check of the data stored in the EEPROM is completed. After checking all areas, the microcomputer starts control. At this time, the microcomputer writes data such as usable area learning values.

FIG. 5 shows the sequence when the update of the EEPROM storage data occurs while the microcomputer is controlling the engine. During control, a SUM check is performed each time data is updated, and the SUM value is updated, so that the content of the trouble will occur at the next startup. The data is updated in 201 and 202
The SUM is calculated in step 3, the SUM is written in the EEPROM in step 203, and the SUM is checked in step 204 in the procedure shown in FIG.

In the present invention, for example, some area is NG
However, since other areas can be used, re-learning etc. is possible even if the EEPROM is partially broken.

When the same data is stored in all of the divided areas, the initial learning value is long because the other areas can be used even if the EEPROM is partially broken and one area becomes NG. Can be held for a period.

[0024]

The reliability of the data held can be improved by dividing the data area of the EEPROM.

[Brief description of drawings]

FIG. 1 is an engine control system diagram.

FIG. 2 is a configuration diagram of a control unit.

FIG. 3 is an EEPROM area division diagram.

FIG. 4 is an EEPROM data check flowchart.

FIG. 5 is an EEPROM data rewriting flowchart.

[Explanation of symbols]

1 ... Control unit, 37 ... Microcomputer, 41 ... RAM, 42 ... ROM, 43 ... CPU, 46
… EEPROM.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akito Numata 2477 Kashima Yatsu Kashima, Katsuta City, Ibaraki Prefecture 3 Hitachi Automotive Engineering Co., Ltd.

Claims (2)

[Claims] 1. A control unit for electronically controlling an automobile, which has an EEPROM built-in, and has an EEPR at a predetermined timing.
EEPROM in the control unit that diagnoses OM
The data area of each data area is divided into a plurality of data areas, and the sum total value of data in each data area (hereinafter referred to as SUM) is stored in the corresponding area. An automobile control unit characterized by comparing the stored SUM with the quality of the EEPROM data. 2. The EEPROM division according to claim 1 is divided into a plurality of three or more, the same data is written in each area, each SUM is compared, and when any one is abnormal, the data to be used is decided by majority decision. A control unit for automobiles that is characterized by: