JP3495613B2 - Electronic control system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a countermeasure when a communication failure occurs between electronic control units in an electronic control system having at least two electronic control units, and particularly to an electronic control suitable for engine control of passenger cars. Regarding the system.

[0002]

2. Description of the Related Art For example, in an electronic control system for a passenger car engine, a plurality of electronic control units (hereinafter referred to as ECU
(Referred to as ") is used to connect the ECUs by communication. This method has the following advantages. The burden on the main ECU is reduced, and more complicated control is possible. Individual ECU for changing specifications
In some cases, it may be possible to deal with it only by changing the specifications, and it becomes easy to change the specifications. It is also advantageous in terms of cost as a whole.

In order to reduce the manufacturing cost by reducing the number of wirings, high-speed serial communication is generally used for communication between ECUs. However, in high-speed serial communication, communication may not be performed normally due to noise or voltage drop. Various proposals have been made for measures to be taken when a communication abnormality occurs between such electronic control units. The electronic control system proposed in JP-A-5-231233 individually detects an abnormality of each signal transmitted to each communication line, and when the abnormality is detected, data input by the signal is detected. The value on the safe side is used to continue the control based on the signal transmitted from the other communication line which is operating effectively.

In the error processing method in serial communication proposed in Japanese Patent Laid-Open No. 6-168147, the importance of the error of various signals is weighted in advance, and when the error is detected, only the weight of the error is weighted. The count value is counted up, the count value is counted down when no error is detected for a predetermined period, and the fail operation is executed when the count value reaches a predetermined value.

Regarding the abnormality of the electronic control of the vehicle, as disclosed in JP-A-6-66196 or JP-A-6-66197, the abnormality is detected so that the cause of the failure can be investigated later. Saving of state memory is being done.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
No. 233 and Japanese Patent Laid-Open No. 6-168147 do not mention the processing when the abnormality is resolved, but when the operation by the fail-safe function is continued for a long time, the accelerator is depressed. For a long time, if the driver forgets that the communication is abnormal and the control is performed in a normal state immediately after the communication abnormality is corrected, an unexpected operation of the driver may occur, which may be dangerous.

According to the error processing method in serial communication proposed in Japanese Unexamined Patent Publication No. 6-168147, a fail-safe operation is performed by a burst error caused by a concentration of communication failures in a short period of time, and a communication failure state of a short period is recovered. Even then, it will not be possible to return to normal operation.

There is a transient noise that occurs sporadically in communication, and as suggested in JP-A-6-66196 or JP-A-6-66197, there is also an abnormality due to a sporadic noise. If all of them are saved, it will be difficult to distinguish them from the abnormalities that occur continuously when the device is diagnosed later, and the diagnosis will be complicated.

The present invention has been made to solve the above problems, and an object thereof is fail-safe when a serious communication failure such as disconnection occurs without being influenced by transient noise or the like. It is an object of the present invention to provide an electronic control system that continues operation and saves a memory of an abnormal state.

Another object of the present invention is to provide an electronic control system capable of returning to normal control for a short-term communication failure.

[0011]

SUMMARY OF THE INVENTION An electronic control system according to the present invention comprises a main electronic control unit for comprehensively controlling an engine or a vehicle body and a throttle valve to be operated.
In an electronic control system in which a sub electronic control unit for controlling the opening degree is connected by a communication line, the sub electronic control unit includes a determination unit for determining whether or not the communication content is normal, and when the communication content is not normal, Low engine output
In order to reduce the throttle valve opening when normal
Continued control to reduce than the normal operation amount to control, if the communication contents became normal within a predetermined time period after no normal, the scan in the normal operation the amount of control when the normal
If the rottle valve opening is controlled so that it does not become normal within the predetermined period and becomes normal after the predetermined period has elapsed, it is configured to continue the control when the communication content is not normal. is there.

Further, the electronic control system of the present invention comprises a transmitting side electronic control unit for calculating and outputting an operation target value, and an operation target for receiving the operation target value so that the operation amount becomes the operation target value. In an electronic control system including a reception side electronic control unit for controlling engine ignition and supply fuel , the reception side electronic control unit determines whether the received operation target value is a normal value or not. If the operation target value received is provided with a judging means, and is not a normal value,
Ignition and supply fuel to reduce engine output
There is a thinning out of the normal operation amount that is controlled during normal operation, or there is
If the received operation target value becomes normal within a predetermined period after the received operation target value becomes abnormal, the ignition or supply is adjusted to reach the received operation target value.
When the fuel supply is controlled by the regular operation amount and does not become normal within the predetermined period and becomes normal after the predetermined period has elapsed , the control is continued when the communication content is not normal. It was done.

In each of the electronic control systems,
When the operation target value received within the predetermined period does not become normal, the abnormal state is stored in the non-volatile memory.

In each of the electronic control systems,
The predetermined period is configured to be clocked only when the power supply voltage is equal to or higher than a predetermined value.

[0015]

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A passenger car engine control system according to an embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a main part of an engine control system of an embodiment. Reference numeral 1 shown in the drawing is a main ECU, and CP
It has a U, a ROM, a RAM and a RAM (nonvolatile memory) in which the memory is saved even when the key switch is turned off. By an input line not shown in the main ECU 1,
Signals from an accelerator sensor, a water temperature sensor, an intake air temperature sensor, a rotation angle sensor, etc. are input, and an ignition signal and an injection valve drive signal are output via an output line (not shown). Main E
The CU further communicates with the sub ECU 2 via the communication lines 7 and 8, and by connecting an input / output line to the failure diagnosis device, communication with the failure diagnosis device becomes possible.

The throttle valve 4 arranged in the engine intake pipe 3 is opened and closed by a rotary solenoid 5 whose current is controlled by the sub ECU 2. The throttle position sensor 6 is connected to the shaft of the throttle valve 4 and outputs an opening signal of the throttle valve 4 to the sub ECU 2. The sub-ECU 2 has a CPU, a ROM, a RAM, and a RAM that retains memory even when the key switch is turned off.
(Non-volatile memory). Normally, the sub ECU 2
Controls the electric current of the rotary solenoid 5 so as to reach the target opening value of the throttle valve 4 calculated and transmitted by the main ECU 1.

The main ECU 1 calculates a target opening value of the throttle valve 4 from various input signals to calculate the sub ECU.
2, the format of the transmission signal is determined to transmit n pieces of data in t seconds as shown in FIG. 2, and the last piece of data is data for checking called a checksum. There is. The sub-ECU 2 determines that the communication is defective when the number of received data is insufficient (when there is no n data) or when the sum of the data and the checksum are not equal.

Next, the operation of the sub ECU 2 will be described with reference to the flowcharts of FIGS. The routine shown in FIG. 3 is periodically executed to handle a communication failure. In this routine, it is first determined in step S1 whether the communication failure flag is 1. If the communication failure flag is 1, the process proceeds to step S2, and if it is 0, the process proceeds to step S9. In step S9, the communication failure time counter is set to a predetermined value, and the process proceeds to step S10.

In step S10, it is determined whether or not a communication failure has occurred, and if so, the process proceeds to step S11. If the communication is normal, the process proceeds to step S12. In step S11, the communication failure flag is set to 1, and this routine ends. In step S12, the communication failure flag is set to 0.
This routine ends.

In step S2, it is determined whether or not the normal recovery non-permission flag is 0. If it is 0, the process proceeds to step S3, and if it is not 0, this routine is ended. In step S3, it is determined whether or not the communication failure time counter is 0. If it is 0, the process proceeds to step S4, and if it is not 0, the process proceeds to step S5.

In step S5, it is determined whether the power supply voltage is normal, and if normal, the process proceeds to step S6.
If the power supply voltage is lower than the normal range, step S7
Move to. In step S6, the communication failure time counter is decremented and the process proceeds to step S7.

In step S7, it is determined whether or not communication is normally performed. If normal, the process proceeds to step S8, and if not normal, this routine is ended. In step S8, the communication failure flag is set to 0, and this routine ends.

When the state of communication failure continues for a predetermined period, step S4 is executed and the normal recovery non-permission flag is set to 1
This routine ends. The normal recovery non-permission flag can be read by the failure diagnosis device via the main ECU 1 and can be reset via the main ECU 1.

As described above, according to the routine shown in FIG. 3, the communication failure flag is set in the case of a communication failure, and the normal recovery disapproval flag is set when the communication failure continues for a predetermined period in the power supply normal state. Flag is sub ECU
The control operation of the second throttle valve 1 is restricted. FIG. 4 shows a flowchart of a control operation routine of the throttle valve 1 of the sub ECU 2.

This control operation routine is executed periodically. First, in step S20, it is judged whether or not the communication failure flag is 1, and if it is 1, the process proceeds to step S23, and if it is 0, step S21. Move to. In step S21, it is determined whether or not the normal recovery non-permission flag is 1, and if it is 1, the process proceeds to step S23 and 0
If it is, the process proceeds to step S22.

In step S23, as a fail-safe operation in case of communication failure, the throttle valve opening amount is decreased in order to reduce the engine output. For example, the throttle valve opening may be set to a predetermined ratio (for example, 1/2) of the normal engine output, or the degree of change of the throttle valve opening with respect to the accelerator opening in the accelerator depression direction may be reduced. The current supplied to the rotary solenoid 5 is set so as to limit the maximum opening position of the throttle valve opening, and this routine is finished.

In step S22, normal throttle valve control is performed, and the opening of the throttle valve is set to the main E
The current value supplied to the rotary solenoid 5 is calculated so as to reach the target opening value transmitted from the CU, and the current having the current value is output to the rotary solenoid 5, and this routine is ended.

As described above, when the communication failure continues for a certain period of time by the routines shown in FIGS. 3 and 4, the fail safe operation is continued even if the communication becomes normal. As a result, even if the driver, who is accustomed to the fail-safe operation for a long period of time, operates to depress the accelerator, a sudden change in the engine operating state does not occur and safety is ensured.

By properly setting the period during which the normal recovery non-permission flag is set, it is possible to prevent the normal operation from becoming impossible due to transient noise or the like. Further, by not counting the communication failure time counter at the time of voltage drop, it is possible to prevent the normal recovery from being impossible in the case of poor charging of the battery. The continuation of a communication failure for a long time may be a sign of a serious failure such as a disconnection, and in such a case, necessary maintenance can be secured by saving the failure memory.

Although a rotary solenoid is used as the actuator in the embodiment, the present invention can be applied to a DC motor and a stepper motor.

Further, in the embodiment, the opening of the throttle valve is operated as the fail-safe operation, but ignition control (thinning-out thinning), cylinder control (rest of some cylinders), fuel control (output is reduced). The method of controlling the air-fuel ratio) can be applied to the present invention because the output can be reduced by controlling the ignition and the supplied fuel to a predetermined value smaller than the normal operation amount.

[0033]

As described above, according to the electronic control system of the present invention, when controlling the engine of a passenger car, there is a risk of a sudden change in the operating state of the engine when a communication failure is recovered for a long period of time. It can be prevented. In addition, the history of long-term communication failures is saved, and maintenance is performed at a low cost. Further, it is possible to automatically restore normality to a communication failure due to transient noise or the like.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of an engine control system according to an embodiment of the present invention.

FIG. 2 is a time chart showing a communication format of the control system.

FIG. 3 is a flowchart showing an operation of the control system.

FIG. 4 is a flowchart showing an operation of the control system.

[Explanation of symbols]

1 Main ECU 2 Sub ECU 3 engine intake pipe 4 Throttle valve 5 Rotary solenoid 6 Throttle position sensor 7,8 communication line

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F02D 41/22 310 F02D 41/22 310G G06F 11/00 350 G06F 11/00 350F 11/34 11/34 H 13/00 301 13 / 00 301D (72) Inventor Mitsuhiro Miyake 5-3-8, Shiba, Minato-ku, Tokyo Within Mitsubishi Motors Corporation (72) Inventor Toru Hashimoto 5-33-8, Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (56) References JP-A-10-238388 (JP, A) JP-A-6-137182 (JP, A) JP-A-11-141383 (JP, A) JP-A-8-284729 (JP, A) JP-A-8-8924 (JP, A) JP-A-5-99061 (JP, A) JP-A-9-160602 (JP, A) JP-A-6-74078 (JP, A) JP-A-9-112311 (JP, A) JP-A-62-3312 (JP, A) Open flat 6-272612 (JP, A) JP Akira 63-314661 (JP, A) JP Akira 62-55442 (JP, A) (58 ) investigated the field (Int.Cl. ^7, DB name) F02D 9 / 00-11/10 F02D 13/00-28/00 F02D 41/00-41/40 F02D 43/00-43/04 F02D 45/00 F01P 5/145-5/155 B60R 16/02 G11C 17/00

Claims (4)

(57) [Claims] 1. A main electronic control unit for comprehensively controlling an engine or a vehicle body, and a slot to be operated.
In an electronic control system in which a sub electronic control unit that controls the valve opening is connected by a communication line, the sub electronic control unit includes a determination unit that determines whether or not the communication content is normal. Of the engine
Normalize the throttle valve opening to reduce the output
If the communication continues to be controlled to reduce the normal operation amount to be controlled at the time of normal, and becomes normal within a predetermined period after the communication content is not normal, the throttle valve is controlled at the normal operation amount to be controlled when normal. An electronic control system configured to control the opening degree and not to be normal within the predetermined period, and to continue the control when the communication content is not normal when the normality is obtained after the predetermined period has elapsed. 2. A transmission-side electronic control unit that calculates and outputs an operation target value, and an engine that is an operation target so that the operation amount becomes the operation target value by receiving the operation target value .
In an electronic control system including a reception side electronic control unit that controls ignition and supply fuel , the reception side electronic control unit includes a determination unit that determines whether the received operation target value is a normal value, If the operation target value is not normal , the above-mentioned points are set in order to reduce the engine output.
Than the normal manipulated variable that controls the fire and fuel supply at normal times
If the received operation target value becomes a normal value within a predetermined period after continuing the control for thinning or reducing the operation target value, the ignition or supply fuel is adjusted to the received operation target value. Is controlled by the regular operation amount, does not become normal within the predetermined period, and becomes normal after the predetermined period elapses, the communication content is not normal.
Electronic control system configured to continue the control of. 3. The electronic control system according to claim 1, wherein the abnormal state is stored in a non-volatile memory when the operation target value received within the predetermined period is not normal. 4. The electronic control system according to claim 1, wherein the predetermined period is timed only when the power supply voltage is equal to or higher than a predetermined value.