JPH04159440A - Self-diagnostic method in electronic engine control device - Google Patents

Abstract

PURPOSE:To reduce largely ROM contents check processing time by forming ROM contents in 16 bits data comprising even addresses apportioned to the upper 8 bits and odd addresses to the lower 8 bits and adding both data in a bundle. CONSTITUTION:When CPU 3 is started by means of an ignition key or when CPU 3 is restarted after being reset at the time of supply voltage drop or instantaneous supply interruption, the contents of ROM 6 are bundled by defining even addresses to the upper 8 bits and odd addresses to the lower 8 bits so that they may be taken into a 16-bit resistor 5, and the addition is carried out over all addresses in ROM. The result of the addition in the upper 8 bits is compared with a set value determined beforehand. When the two values are not in agreement, an alarm is issued to the drive and at the same time engine control is made by sub CPU 9 as backup, with an abnormality assumed in ROM 6. When the two values are in agreement, on the other hand, signals from various sensors are read from an input unit 2 and the initial setting, such as RAM reset is made for engine control.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a self-diagnosis method for electronic engine control devices used in automobiles and the like.

Conventional technologyElectronic engine control unit (ECU) used in automobiles, etc.
Because there is a direct danger to life while driving,
Failure is not an option, but in the event of a failure, it is necessary to immediately notify the driver and take backup steps. Therefore, the ECU has a self-diagnosis device that checks whether the contents of the read-only memory (ROM), which stores the execution programs of the central processing unit (CPU) and various control data, are normal. Performs software failure detection.

Generally, ECUs use microcomputers that allocate addresses in 8-bit units, so conventional self-diagnosis devices use the 8-bit content of each address in the ROM as is, as shown in Figure 4. It was treated as data. In addition, the power supply voltage of the ECU periodically decreases to around rOJV because the supply capacity of the on-board battery that is the power source is low, and a large current flows through the starter motor at the time of starting, and the CPU is reset and restarted.

In addition, voltage drop due to cranking etc. may cause CP
U is reset and restarts. Therefore, if the ROM is checked during such a momentary power interruption, the engine control operation cannot be started immediately, and the engine starts poorly, and in the worst case, the engine will stop. Therefore, in order to improve the startability of the engine by checking the ROM only when starting with the ignition key, a check is first made to see if there is a momentary power outage.

Here, a conventional self-diagnosis method for an electronic engine control device will be explained with reference to FIG. First, check whether there is a momentary power outage to the ECU (step 3).
1). If there is no momentary power interruption, such as when starting, add the contents of each address in the ROM to all addresses in step 3.
2) Compare this result with a preset setting value (step 33). If the above result is different from the set value, the contents of the ROM are abnormal, and a warning is given to the driver and backup processing is performed (step 34).
). Also, if the above result matches the above setting value, the ROM
Since the contents of are normal, initial settings such as reading inputs from various sensors and resetting the RAM are performed (step 35), and the process moves to engine control operation (step 36).
). Further, if it is determined in step 31 that there is a momentary power interruption, initial settings are directly performed.

Problems to be Solved by the Invention However, the above-mentioned conventional self-diagnosis method for an electronic engine control device has the following problems.

(1) Since the contents of the ROM are checked by adding data in units of 8 bits, processing time is required due to the large number of data additions. For example, the capacity of ROM is 32 kBy
In the case of te, approximately 70 m5 is required.

(2) Since the ROM is not checked during a momentary power outage, ROM abnormalities cannot be detected at this time, so the CP
There is a risk of the U malfunctioning or running out of control, which poses an obstacle to safety.

The present invention solves the above problems by providing an excellent electronic engine control device that can check the ROM in a short time, improve engine startability, and reliably detect abnormalities. The purpose is to provide a self-diagnosis method.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention divides the contents of a ROM into upper 8 bits for even addresses and lower 8 bits for odd addresses.
By treating it as 16-bit data,
This method reduces the number of data addition processes and detects abnormalities in the ROM in a short time.

Effect The present invention has the above-mentioned configuration, so that the RO when starting the engine is
Since M can be checked in a short time, engine startability can be improved.

Embodiment FIG. 1 is a schematic block diagram of an electronic engine control unit (ECU) in which the self-diagnosis method for an electronic engine control unit of the present invention is used. In Fig. 1, 1 is the ECU main body, 2 is an input section into which output signals from the throttle opening sensor, intake pressure sensor, etc. are input, and 3 is an engine (not shown) based on the signals from the input section. ), and consists of a control section 4 and a 16-bit register 5. 5 is 1
It is a 6-bit register, and takes in the contents of the ROM 6 as 16-bit data, with the even address being the upper 8 bits and the odd address being the lower 8 bits. 6 is a ROM in which execution programs and various control data for the CPU 3 are stored;
7 is a sub-CPU that controls the engine when the CPU 3 or ROM 4 is abnormal, and the number of functions that can be controlled is smaller than that of the CPU 3. 8 is CP
U3 is an output section that receives an engine control signal output from the sub CPU 7 and outputs it to the engine.

2 and 3 are a memory image diagram and a flowchart, respectively, showing an embodiment of the self-diagnosis method of the present invention. As shown in Figure 2, the contents of the ROM are divided into the upper 8 bits for even addresses and the lower 8 bits for odd addresses.
Treated as 16-bit data.

The present embodiment will now be described with reference to FIG. 3. When the CPU is started by the ignition key, or when the CPU is reset and restarted due to a drop in power supply voltage or momentary power interruption, the contents of the ROM are treated as the upper 8 bits of the even address and the lower 8 bits of the odd address. , and add it to the 16-bit register 5 over all addresses in the ROM (step 1).
1). Next, the result of the upper order addition is compared with a predetermined set value (step 12), and if they do not match, the driver is alerted and a ROM error is detected, and a backup operation is performed in which the engine is controlled by the sub CPU 5 (step 12). 13). If the above result matches the set value, the input section 2 reads signals from various sensors, performs initial settings such as resetting the RAM (step 14), and performs engine control (step 14).
Step 15).

Also, after starting the engine control operation, divide the inside of the ROM into several blocks, check the contents of the ROM for each block (step 16), and if it is normal, continue engine control, or if there is an abnormality. If the above
Perform a backup operation similar to the sofa knob operation (
Ste Tubu 18).

In this way, according to this embodiment, the contents of the ROM are treated as 16-bit data, with the even address being the upper 8 bits and the odd address being the lower 8 bits, and being added, the number of data additions is in units of 8 bits. In the case of a 32 kByte ROM, the processing time for checking the ROM contents can be significantly reduced from the conventional 70 m5 to 30 IIIs or less.

Furthermore, since the time to check the ROM contents can be greatly reduced, there is no need to judge instantaneous power outages, and the R
Since the contents of the OM are checked, abnormalities in the ROM can be reliably detected, ensuring startability and high safety.

Effects of the Invention As is clear from the above embodiments, the present invention imports the contents of a ROM into a 16-bit register as 16-bit data with the upper 8 bits at the even address and the lower 8 bits at the odd address, and stores the 16-bit data. Since the data are added together, the number of data additions is only half that of adding in 8-bit units, which has the effect of significantly reducing the processing time for checking the ROM contents.

Furthermore, since the time to check the ROM contents can be greatly reduced, there is no need to judge instantaneous power outages, and the R
Since the contents of the OM are checked, abnormalities in the ROM can be reliably detected, ensuring startability and high safety.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of an electronic engine control device used in the self-diagnosis method for an electronic engine control device of the present invention, and FIG. 2 is a memory image diagram when the contents of RoM are treated as 16-bit data in the present invention. FIG. 3 is a flowchart showing the operation of the self-diagnosis method according to the present invention, FIG. 4 is a memory image diagram of the conventional example, and FIG. 5 is a flowchart of the conventional example. 1... ECU body, 2... Input section, 3
...CPU, 4...Control i, 5-...
・-・16-bit register, 6...ROM, 7
......Sub CPU, 8...Output section. Name of agent: Patent attorney Akira Koebushi and 2 others / −
--E t, u 7 J$. 3-cPu Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In an engine control device using a microcomputer that allocates addresses in 8-bit units, the even addresses of the read-only memory are taken into a 16-bit register as the upper 8 bits and the odd addresses are treated as the lower 8 bits, and this 16-bit data is grouped together. A self-diagnosis method for an electronic engine control device, characterized in that an abnormality in a read-only memory is detected by comparing the result of addition with a preset 16-bit setting value.