JP3302739B2 - Control unit diagnostic device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for diagnosing a control unit, and more particularly to an apparatus for diagnosing an abnormality in a read-only memory in which various control programs and control data are digitized and stored.

[0002]

2. Description of the Related Art With the recent progress in electronics, for example, in the case of automobile engines, a control unit using a so-called microcomputer or the like is used in accordance with an operating state for the purpose of improving fuel efficiency and exhaust performance. Is precisely controlled. That is, in the control unit, a read-only memory (hereinafter, referred to as ROM) in which various control programs and control data set in an optimum state at a manufacturing stage are written as binary data of “0” and “1”.
And a central processing unit (hereinafter referred to as C) that executes various arithmetic processing and control processing according to a control program stored in a ROM.
PU), and adjusts a fuel supply amount, an ignition timing, and the like according to a signal indicating an operating state of the engine taken from various sensors and control data stored in the ROM. Is operated in an optimal state.

In this type of control unit, the storage contents of the ROM may be different from the initial storage contents due to the influence of radiation, modification, and the like. May not be performed .

To solve such a problem, for example, Japanese Unexamined Patent Publication No. 57-171046 discloses a ROM check processing for turning on a display switch for displaying a diagnosis result on a display of an engine self-diagnosis alarm display device. Is thought to be performed .

[0005]

However, considering the safety of the system, it is not preferable to rely on the driver's intention to check the ROM. That is, the ROM is not checked at all until the driver turns on the display switch, for example.
In addition to the possibility that the abnormal state of M may be left for a long period of time, even if the ROM has been irregularly remodeled, it will not be possible to properly cope with it.

[0006]

According to the present invention, there is provided a ROM in which various control programs and control data are digitized and stored;
Those using the control data stored to address the above problems in the control unit and a control unit for controlling the automatically determined the abnormality of the upper Symbol ROM
The main object of the present invention is to ensure that the safety of the vehicle can be maintained well .

[0008]

Means for Solving the Problems That is, the diagnostic device of the control unit according to the inventions of claim 1 of the present application, a read only memory in which various control programs and control data are stored are quantified, A control unit for performing engine control according to the operating state using the control data stored in the memory,
Using data stored in the read only memory, starting
And during the abnormality determination means for determining an abnormality of the memory during normal operation when unactuated, eye determines idling
In addition to providing dollar operating state determination means , during normal operation
When a memory abnormality is determined by the abnormality determination means,
The idle operation state is determined by the idle operation state determination means.
Engine power is reduced when it is determined that
On the other hand, even if a memory abnormality is determined,
If the status is not determined, a memory error
Not to reduce the engine output based on
Characterized in that it is provided with a reduced engine output means .

[0009]

[0010]

[0011]

[0012]

According to the above arrangement, the following operation can be obtained.

[0013]

According to the present invention, when the abnormality of the read-only memory is detected, the engine output is reduced. Therefore, even if the memory is modified so as to increase the engine output, the vehicle is not modified. Will be maintained in good condition.

[0015]

In particular, according to the present invention, the engine output
Since the reduction is performed during the idle operation of the engine, the engine output is stably reduced without causing engine stall.

[0017]

Embodiments of the present invention will be described below.

As shown in FIG. 1, a combustion chamber 2 of an engine 1
Are connected to an intake passage 5 and an exhaust passage 6 via intake and exhaust valves 3 and 4, respectively. In the intake passage 5, an air flow sensor 7 for detecting the amount of intake air taken into the combustion chamber 2 from the upstream side, a throttle valve 8 for adjusting the amount of air or the engine output, and an injector for supplying fuel to the combustion chamber 2 9 and the combustion chamber 2
A high voltage is applied to the ignition plug 10 installed in front of the ignition module 10 in synchronization with an energization control signal input to the ignition module 11.

On the other hand, a catalytic converter 12 for purifying exhaust gas is provided in the exhaust passage 6, and an O ₂ sensor 13 for detecting the residual oxygen concentration of the exhaust gas is arranged upstream of the converter 12. I have.

Further, the engine 1 is provided with a control unit 20. The control unit 20 includes a start signal from a start switch 31, an engine speed signal from a rotation sensor 32 for detecting the engine speed, and a crank signal from a crank angle sensor 33 for detecting the rotation angle of the crankshaft of the engine 1. An angle signal, an intake air amount signal from the air flow sensor 7,
A throttle opening signal from a throttle sensor 34 for detecting the opening of the throttle valve 8, an idle signal from an idle switch 35 for detecting the fully closed state of the throttle valve 8, and a water temperature sensor 36 for detecting the engine water temperature. A water temperature signal, an air-fuel ratio signal from the O ₂ sensor 13, and a vehicle speed signal from a vehicle speed sensor 37 that detects the vehicle speed of the vehicle are input, and a fuel injection amount from the injector 9 is determined based on these signals. The engine 1 is controlled by controlling the ignition timing for the spark plug 10.

As shown in FIG. 2, the control unit 20 includes a ROM 21 in which various control programs and control data are stored, and a C / C for executing various calculations and controls.
PU22 and RAM2 for temporarily storing calculation results and the like
And 3. Then, the CPU 22 executes the input processing circuit 24
Are selectively fetched via a bus line 41 according to various programs stored in the ROM 21 and input to an input port P2 of the injector drive circuit 25 via an output line 42 connected to the output port P1. A fuel injection signal is output, and an ignition output processing circuit 26 is output via an output line 43 connected to the output port P3.
Output an ignition signal to the input port P4.

Here, the outline of the fuel injection control and the ignition timing control performed by the CPU 22 will be described. First, the fuel injection control is performed as follows.

That is, the CPU 22 determines whether or not the engine 1 is started based on the start signal from the start switch 31 and the engine speed signal from the rotation sensor 32. After reading out the predetermined start-up injection pulse width, the final start-up injection pulse width is determined in consideration of the invalid injection time. Then, after the final start-up injection pulse width is amplified by the injector drive circuit 25, a drive signal is output to the injector 9 via the control line 44.

When the CPU 22 determines that it is not at the time of starting, it performs fuel injection control according to the operating state. That is, the CPU 22 calculates the amount of intake air drawn into the combustion chamber 2 per cycle based on the amount of intake air indicated by the signal from the air flow sensor 7 and the engine speed indicated by the signal from the rotation sensor 32. The basic injection pulse width corresponding to the value is called from the ROM 21. And O ₂
The basic injection pulse width is corrected according to the air-fuel ratio signal from the sensor 13, the water temperature signal from the water temperature sensor 36, and the like. In this case, the final injection pulse width is determined in consideration of the invalid injection time. A drive signal corresponding to the final injection pulse width is output to the injector 9.

On the other hand, ignition timing control is generally performed as follows.

That is, the CPU 22 retrieves, from the ROM 21, a basic ignition advance amount corresponding to the operating state indicated by, for example, the intake air amount and the engine speed, and reads the corrected ignition advance amount corresponding to the engine coolant temperature from the basic ignition advance amount. Add to the quantity to determine the final ignition timing. Then, the ignition signal corresponding to the final ignition timing is converted into an energization control signal by the ignition output processing circuit 26, and then output to the ignition module 11 via the control line 45.

The control unit 20 is provided with a backup module 27 for performing backup control of the engine 1 when the CPU 22 is abnormal, and a switching circuit 28 for switching control between the backup module 27 and the CPU 22.

The switching circuit 28 has an input port P connected to an output port P5 of the CPU 22 through a signal line 46.
6 and the input port P of the backup module 27
7 is provided with an output port P8 which communicates via a signal line 47.

On the other hand, the backup module 27 is configured to receive a crank angle signal and an idle signal via input lines 48 and 49, and one output port P9 is connected via an output line 50 to an injector. The input port P10 of the drive circuit 25 and the other output port P11 are connected to the input port P12 of the ignition output processing circuit 26 via the output line 51, respectively. In this case, when the CPU 22 is normal, for example, the output port P5 is in the “H” state, and accordingly the output port P8 of the switching circuit 28 is in the “L” state, so that the input port P7 of the backup module 27 is It becomes "L", and the control by the CPU 22 is performed. On the other hand, when an abnormality occurs in the CPU 22 and the output port P5 becomes “L”, the input port P6 of the switching circuit 28 also switches from “H” to “L”, and accordingly, the output port P8 changes from “L” to “L”. "H", the input port P7 of the backup module 27 becomes "H", and control is transferred from the CPU 22 to the backup module 27. That is, for example, the input port P2 of the injector drive circuit 25 and the input port P4 of the ignition output processing circuit 26 are grounded by the control signal output from the backup module 27, and the signal from the CPU 22 is disabled. . Therefore, the fuel injection amount from the injector 9 and the ignition timing for the ignition plug 10 are controlled to the fixed values set in the backup module 27, respectively.

In this embodiment, the above CP
U22 is provided with an output port P13 which is set to "L" when the ROM 21 is abnormal.
The signal line 52 connected to the switching circuit 13 is connected to an input port P14 provided in the switching circuit 28.

Next, the engine control in this embodiment will be described with reference to the flowchart of FIG.

That is, the CPU 22 initializes the system in step S1 and clears the RAM 23 and the like, and determines in step S2 whether or not the engine is starting. When it is determined that the engine is in starting, the CPU 22 performs predetermined starting control in step S3. At the same time, if it is not at the time of starting, step S3 is skipped and the routine proceeds to step S4, where normal control according to the operating state of the engine 1 is performed.

Next, in step S5, the CPU 22 determines whether or not the self-diagnosis flag F1 is set to 1 indicating a normal state.
The sum of every 1 Kbyte in the order of the address of OM21 is the intermediate value A
In step S7, a value obtained by adding the intermediate value A to the integrated value S is set as a new integrated value S, and R is set in step S8.
It is determined whether or not the addition has been completed up to the final address of the OM 21. The loop processing of steps S4 to S8 is executed until the determination is YES, and when the determination is YES, the process exits the loop processing and proceeds to step S9 to proceed to step S9. It is determined whether or not the integrated value S matches the reference value So.

That is, as shown in FIG. 4, when the storage area of the ROM 21 is 1 Mbyte with 8 bits as 1 byte, the value of each bit in 1 block up to 1 Kbyte is added in the first addition processing. 2K in the next addition process
The value of each bit in one block up to the byte is added. Therefore, the addition time per operation is greatly reduced as compared with the case where 1M bytes of ROM data are added all at once. As a result, the engine 1 is controlled to reflect the latest operating state, so that deterioration in controllability is avoided.

When the CPU 22 determines in step S9 that the integrated value S matches the reference value So, it executes step S10 and sets the self-diagnosis flag F1 to 1
After returning to step S4, the routine returns to step S4 to execute the normal control of the engine 1.

On the other hand, when the CPU 22 determines that the integrated value S is different from the reference value So, it first determines in step S11 whether or not the vehicle speed V of the vehicle indicated by the signal from the vehicle speed sensor 37 is zero. If it is determined, then in step S12, it is determined whether or not the idle signal from the idle switch 35 indicates the fully closed state of the throttle valve 8, and if it is determined that the throttle valve 8 is fully closed, the process proceeds to step S13 to determine whether the abnormality flag F2 After setting the value to 1 indicating an abnormal state of the ROM 21, the mode is shifted to the backup mode in step S 14, and the control is passed to the backup module 27.

That is, as shown in FIG.
When 2 is set to 1, the output port P13 of the CPU 22 and the input port P14 of the switching circuit 28 are respectively switched from "H" to "L", and the output port P8 of the switching circuit 28 is accordingly switched to "L". To "H", the input port P2 of the injector drive circuit 25 and the input port P4 of the ignition output processing circuit 26 are respectively grounded, and the signal from the CPU 22 cannot be received. As a result, the fuel injection amount from the injector 9 and the ignition timing for the spark plug 10 are controlled to the fixed values set in the backup module 27, and the engine output decreases.

In this case, since the backup module 27 is generally provided in the control unit 20 to perform backup control of the engine 1 when the CPU 22 is abnormal, a special program or control for lowering the engine output is used. No data is required, and an increase in the amount of memory used is avoided, so that an increase in the cost of the control unit 20 is suppressed.

Further, since the ROM 21 is automatically checked, irregular modifications can be appropriately dealt with, and the engine output is reduced at the time of abnormality determination. Will be further improved.

Then, as in the embodiment, when the abnormality of the ROM 21 is determined, the control is transferred to the backup module 27 when the engine 1 is idling, so that the engine output causes engine stall. And will be reduced stably.

[0041]

[0042]

As described above, according to the present invention, when an abnormality in the read-only memory is detected, the engine output is reduced, so that the memory is modified so as to increase the engine output. Even if it is applied, the safety of the vehicle will be favorably maintained.

[0043]

In particular, according to the present invention, the engine output is low.
Since the lower is carried out during idling of the engine, so that the engine output is reduced stably without generating engine stall.

[Brief description of the drawings]

FIG. 1 is a control system diagram of an engine.

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

FIG. 3 is a flowchart illustrating engine control in the embodiment.

FIG. 4 is a memory configuration diagram of a ROM.

FIG. 5 is a time chart illustrating the operation of the embodiment.

[Explanation of symbols]

 Reference Signs List 20 control unit 21 ROM 22 CPU 27 backup module 28 switching circuit 35 idle switch 37 vehicle speed sensor

Continuation of the front page (56) References JP-A-3-238541 (JP, A) JP-A-4-1450 (JP, A) JP-A-55-128641 (JP, A) JP-A-58-46411 (JP) JP-A-59-28030 (JP, A) JP-A-59-128948 (JP, A) JP-A-60-212655 (JP, A) JP-A-1-87850 (JP, A) 1-294935 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01R 31/00 F02D 45/00 376 G01M 15/00

Claims (1)

(57) [Claims] 1. A read-only memory in which various control programs, control data, and the like are digitized and stored, and the control data stored in the memory correspond to an operation state.
A diagnostic device of the control unit and a control unit for controlling the engine, by using the data stored in the read only memory, the normal operation during starting and unactuated
Sometimes the abnormality determination means for determining an abnormality of the memory, I
Idle operating state determining means for determining a dollar operating state, and the abnormality determining means during normal operation.
If the memory abnormality is determined in
The operating state determination means determines that the vehicle is in the idle operating state.
When the engine output is reduced,
Even if it is determined that the
If not, the engine based on the memory error
Engine power configured to not reduce power
A diagnostic device for a control unit, comprising a lowering means .