JP2000286876A - Communication control system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a communication control system for a vehicle to reduce effect of reception abnormality. SOLUTION: In a communication system for a vehicle where a plurality of control units communicate information with each other via a common signal line, the system discriminates occurrence of interruption denoting disabled reception of request information while not receiving an end signal of the request information (step 2), diagnoses occurrence of failure in reception when an interruption time T5 reaches a prescribed reception fault discrimination time Tout5 or over (step 4) and releases communication control with a control unit being a transmission destination on the occurrence of the reception fault (step 5).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to abnormality diagnosis of a communication control device for transmitting digital signals between control units of a vehicle.

[0002]

2. Description of the Related Art Conventionally, a time division multiplex communication system in which various control units including an engine control unit and a transmission control unit mounted on a vehicle are connected to a common signal line and digital signals are transmitted between the control units. is there. With this communication system, the wiring of the vehicle can be significantly reduced (see JP-A-10-157648).

[0003]

However, in such a conventional communication system, the signal of the request information is not received while the end signal of the request information is not received, or the request value is out of the specified range. When a reception error occurs, it is necessary to promptly return to the original control which is not affected by the request information.

The present invention has been made in view of the above problems, and has as its object to reduce the influence of abnormal reception in a vehicle communication control device.

[0005]

The first invention is applied to a vehicle communication system for transmitting and receiving information between a plurality of control units via a common signal line.

[0006] An interruption time judging means for judging an interruption time when the signal of the request information is no longer received while the end signal of the request information is not received, and a case where the interruption time exceeds a predetermined reception abnormality judgment time. It is provided with a reception abnormality diagnosis means for diagnosing a reception abnormality and a communication control release means for releasing communication control with the destination control unit when the reception is abnormal.

In a second aspect, a specified range excess time determining means for determining when a required value is out of a specified range is provided, and a case where the specified range excess time exceeds a predetermined reception abnormality determination time. It is provided with a reception abnormality diagnosis means for diagnosing a reception abnormality and a communication control release means for releasing communication control with the destination control unit when the reception is abnormal.

According to a third aspect of the present invention, in the first or second aspect, there is provided a cranking time determining means for determining when the engine is cranking, and a diagnostic condition determining means for not performing a diagnosis upon abnormal reception during cranking. It was prepared.

[0009]

According to the first aspect of the present invention, the interruption time when the signal of the request information is not received while not receiving the end signal of the request information sent from another control unit is determined, and the interruption time is determined by a predetermined time. By diagnosing the case where the reception abnormality determination time has been exceeded or longer and determining that the reception is abnormal, and canceling the communication control with the destination control unit when the reception is abnormal, the influence of the reception abnormality can be suppressed to a small level.

[0010] In the second invention, it is determined that the required value is out of the specified range when the specified range is exceeded, and when the specified range excess time is equal to or longer than a predetermined reception abnormality determination time, it is diagnosed that the reception is abnormal. By canceling the communication control with the control unit of the transmission destination at the time of reception abnormality, the influence of the reception abnormality can be suppressed to a small level.

According to the third aspect of the present invention, it is possible to judge whether the engine is cranking, and not to perform a diagnosis for abnormal reception at the time of cranking. Can be prevented.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, a CA mounted on a vehicle
An N (control area network) communication system includes an engine control unit 2 and a transmission control unit 3 for a signal line 1, a service brake control unit (not shown), an exhaust brake control unit,
A retarder control unit, a multiplex information display panel control unit, and the like are connected to each other, and these control units 2, 3,.
Information is transmitted / received between the two via a common signal line 1. The signal line 1 is constituted by a pair of electric wires for communicating information, and both ends of each electric wire are connected via the terminating resistor 4, so that the wiring of the vehicle can be greatly reduced.

Each of the control units 2, 3,... Is mainly composed of a microcomputer composed of a CPU, a memory, an I / O, etc., and has a program set in advance in accordance with an operation state detection signal from various sensors. Various actuators are actuated based on this.

For example, the engine control unit 2 inputs operating state detection signals, such as an engine speed sensor and an accelerator opening sensor (not shown), via an I / O, and outputs a map set in advance in accordance with these detection signals. , And outputs a control signal to a fuel injection pump (not shown) via the I / O to control the operation of the engine.

Each of the control units 2, 3,... Has a CAN chip 5 as an input / output device for digital signals transmitted and received via the signal line 1. The CAN chip 5 includes a circuit for data communication, and sets a communication procedure, a communication error process, a data format, a data type, a data resolution, a range, and the like.

For example, the engine control unit 2 inputs a command value of an engine speed and an engine torque from the transmission control unit 3 via the CAN chip 5 at the time of a shift operation of the transmission, so that the engine is operated so that the shift operation is performed smoothly. Operation control.

FIG. 2 shows an example of controlling the engine torque in the engine control unit 2. The override control mode signal 00 in the request information input via the CAN chip 5 corresponds to the end signal of each request information. When the speed changes from 01 to 10, 10 or 11, the mode is switched from the normal control mode in which the communication control has been released to the communication control mode with the transmission control unit 3 at the time of shifting, so that the control value becomes smaller than the original value. In this communication control mode, when the override control mode signal in the request information returns to 00 again, the communication control mode is terminated, and the control value gradually approaches the original value, and when the control value matches the original value. Return to the normal control mode.

The engine control unit 2 interrupts the request information which has stopped receiving the request information signal in the state where the end signal of the request information has not been received, in order to diagnose whether or not the reception error by the CAN signal system has occurred. The time of interruption is determined, and the time of interruption of the request information is determined to be equal to or longer than a predetermined reception abnormality determination time. When the reception is abnormal, the communication control mode with the control units 3,. The information is displayed on the display panel of the vehicle (not shown) to notify the driver. When the request information is received again from the control units 3 for which the communication control mode has been released for a predetermined time, the communication control mode is restarted.

FIG. 3 is a flowchart showing a routine for diagnosing a reception error, which is executed by the engine control unit 2 at regular intervals.

First, in step 1, it is determined whether or not a request information end signal sent from the other control units 3,... Has been received.

If it is determined in step 1 that the end signal of the request information has not been received, the process proceeds to step 2 to determine whether the request information has been continuously received.

If it is determined in step 2 that the request information has been interrupted, the process proceeds to step 3 where the interruption time T5 in which the request information was interrupted is counted. Judgment time Tout5
(For example, 50 ms).
The processing performed in step 2 corresponds to the interruption determination means of the present invention, and the processing performed in step 4 corresponds to the reception abnormality diagnosis means.

If it is determined in step 4 that the interruption time T5 has become equal to or longer than the reception abnormality determination time Tout5, the process proceeds to step 5, where it is diagnosed that an abnormality has occurred in the destination control units 3,. Individually cancels the communication control mode with the destination control units 3,.
The processing performed in step 5 corresponds to the communication control canceling unit of the present invention.

On the other hand, if it is determined in step 1 that the end signal of the request information has been received, or if it is determined in step 2 that the request information has been transmitted, the process proceeds to step 6 where the interruption time T5 of the request information is reduced. Reception abnormality judgment time Tou
It is determined whether or not t5 or more.

If it is determined in step 6 that the interruption time T5 is equal to or longer than the reception abnormality determination time Tout5, the communication control mode is being canceled, and the flow advances to step 7 to check for an abnormality relating to the control unit 3,. Diagnosed as resolved,
The communication control mode with the destination control units 3,... Is restarted.

Then, the program proceeds to a step S8, wherein the counted interruption time T5 is cleared, followed by terminating the present routine.

The engine control unit 2 has a CAN
To determine whether an abnormality has occurred in the signal system, determine when the required value is out of the specified range and exceed the specified range, and the time when the required value exceeds the specified range is equal to or longer than the predetermined reception abnormality determination time When the reception is abnormal, the communication control mode with the destination control units 3,... Is individually released when the reception is abnormal, and error information is displayed on a display board (not shown) to notify the driver. Then, when the control unit 3, which has released the communication control mode, again enters the required information prescribed range, the communication control mode is restarted.

FIG. 4 is a flow chart showing a routine for diagnosing an abnormal reception from the transmission control unit 3, which is executed by the engine control unit 2 at regular intervals.

First, in step 11, it is determined whether or not a request information end signal sent from the transmission control unit 3 has been received.

If it is determined in step 11 that the end signal of the request information has not been received, the process proceeds to step 12, and
It is determined whether the request information has been continuously received.

If it is determined in step 12 that the request information has not been interrupted, the flow advances to step 13 to determine whether the request value is outside the specified range which is larger than the specified upper limit value QextH or smaller than the specified lower limit value QextL. judge. Note that the required value corresponding to the target torque of the engine control unit 2 changes between the upper limit value QextH (for example, 125%) and the lower limit value QextL (-125%). The processing performed in step 13 corresponds to the specified range excess time determination means of the present invention.

If it is determined in step 13 that the required value is out of the specified range, the process proceeds to step 19, where the elapsed time T6 after the required value exceeds the specified range is counted. The elapsed time T6 after the value is out of the specified range is equal to the predetermined required torque value abnormality determination time Tou.
It is determined whether the time has reached t6 (for example, 30 ms) or more.

If it is determined in step 20 that the elapsed time T6 since the request value has fallen outside the specified range has become equal to or longer than the reception abnormality determination time Tout5, the process proceeds to step 21.
The timer value T7 described later is cleared, and the subsequent step 22
Then, it is diagnosed that an abnormality has occurred in the transmission control unit 3, and the communication control mode with the transmission control unit 3 is released. The processing performed in step 20 corresponds to the reception abnormality diagnosis means of the present invention, and the processing performed in step 22 corresponds to the communication control canceling means.

On the other hand, in step 13, it is determined that the required value is within the specified range of not more than the specified upper limit value QextH and not less than the lower limit value QextL, and in step 14, the required value is out of the specified range. If it is determined that the time T6 is equal to or longer than the required torque value abnormality determination time Tout6, the process proceeds to step 15 where the elapsed time T7 after the required value returns to within the specified range is counted. It is determined whether the time T7 is equal to or longer than a predetermined required torque value normal return determination time Tout7 (for example, 20 ms).

If it is determined in step 16 that the elapsed time T7 since the required value has returned within the specified range is equal to or longer than the required torque value normal return determination time Tout7, the abnormality relating to the transmission control unit 3 has been resolved. Then, the process proceeds to step 17 to restart the communication control mode with the transmission control unit 3. The elapsed time T6 counted in the subsequent step 18 is cleared, and this routine ends.

On the other hand, if it is determined in step 11 that the end signal of the request information has been received, the process proceeds to steps 23 and 24 to clear T6 and T7, respectively, and terminates this routine.

FIG. 5 is a flowchart showing a routine for diagnosing a reception abnormality from a brake control unit (not shown). The routine is executed by the engine control unit 2 at regular intervals.

First, at step 31, it is determined whether or not the end signal of the request information sent from the brake control unit has been received.

If it is determined in step 31 that the end signal of the request information has not been received, the process proceeds to step 32,
It is determined whether the request information has been continuously received.

If it is determined in step 32 that the request information has not been interrupted, the flow advances to step 33 to determine whether the request value is other than the specified values QextH and QextL.
The brake control unit is the engine control unit 2
In this case, only the required value QextH for increasing the control value corresponding to the target torque to, for example, 125% of the original value and the required value QextL for increasing the control value to -125% are set to be transmitted. The processing performed in step 33 corresponds to the specified range excess time determination means of the present invention.

If it is determined in step 33 that the required value is not the prescribed value, the flow advances to step 39 to count the elapsed time T8 after the required value has deviated from the prescribed value. The elapsed time T8 is a predetermined required torque value abnormality determination time Tout8 (for example, 30 m).
s) It is determined whether or not the above is achieved.

The elapsed time T8 from when the required value deviates from the specified value in step 40 is the required torque value abnormality determination time Tout.
If it is determined that it has reached 8 or more, the routine proceeds to step 41, where a timer value T9 described later is cleared, and the routine proceeds to the next step 42, where it is diagnosed that an abnormality has occurred in the brake control unit. Release the communication control mode. The processing performed in step 40 corresponds to the reception abnormality diagnosis means of the present invention, and the processing performed in step 42 corresponds to the communication control canceling means.

On the other hand, at step 33, the required value is
xtH, QextL, and step 3
If it is determined in step 4 that the elapsed time T8 since the required value deviated from the specified value is equal to or longer than the required torque value abnormality determination time Tout8, the process proceeds to step 35, and the elapsed time T9 since the required value returned to the specified value. It is determined whether or not the elapsed time T9 counted in the subsequent step 36 has become equal to or longer than a predetermined required torque value normal return determination time Tout9 (for example, 20 ms).

The elapsed time T9 from the return of the required value to the specified value in step 36 is the required torque value normal return determination time T
If it is determined that out9 or more has been reached, it is diagnosed that the abnormality related to the brake control unit has been resolved, and the routine proceeds to step 37, where the communication control mode with the brake control unit is restarted. The elapsed time T8 counted in the subsequent step 38 is cleared, and this routine ends.

On the other hand, if it is determined in step 31 that the end signal of the request information has been received, the process proceeds to steps 43 and 44 to clear T8 and T9, respectively, and terminates this routine.

Thus, when it is determined from the other control units 3,... That the reception is abnormal, the engine control unit 2 stops the communication control mode with the transmission destination, as shown in FIG. The control value gradually approaches the original value, and returns to the normal control mode when the control value matches the original value.

Further, the engine control unit 2 is configured to judge when the engine is cranking and not to perform the abnormality diagnosis of the CAN signal system at the time of cranking. As a result, it is possible to prevent erroneous diagnosis due to the influence of the fluctuation of the power supply voltage during the cranking.

FIG. 6 is a flowchart showing a routine for judging a condition for diagnosing an abnormality of the CAN signal system, which is executed by the engine control unit 2 at regular intervals.

First, in step 51, when it is determined that the ignition switch is turned on and the power of the engine control unit 2 is turned on, the routine proceeds to step 52, where the detected engine speed is set to the cranking start value Nst1.
It is determined whether or not this is the case. This cranking start value Ns
t1 is set in the range of, for example, 30 to 50 rpm, and when the engine speed exceeds the cranking start value Nst1 and rises, it is determined that cranking has started.

If it is determined in step 52 that the engine speed is lower than the cranking start value Nst1 before cranking is started, the routine proceeds to step 53, where abnormality diagnosis of the CAN signal system is permitted.

On the other hand, if it is determined in step 52 that the engine speed is equal to or greater than the cranking start value Nst1, the process proceeds to step 54, where it is determined whether the engine speed is equal to or greater than the cranking end value Nst2. The cranking start value Nst2 is set to, for example, 450 rpm, and when the engine speed exceeds the cranking start value Nst2, it is determined that the cranking has been terminated. The processing performed in steps 52 and 54 corresponds to the cranking time determination means of the present invention.

If it is determined in step 54 that the engine speed is lower than the cranking end value Nst2, the routine proceeds to step 58, where the timer value T3 is cleared, while the engine speed is reduced to the cranking end value Ns.
If it is determined that the cranking has been completed for t2 or more, the timer value T3 is counted in step 56, and step 5 is executed.
Until it is determined that the timer value T3 counted in 5 exceeds the predetermined post-start waiting time Tout3 (for example, 200 ms), the routine proceeds to step 57, and the abnormality diagnosis of the CAN signal system is prohibited. The processing performed in step 57 corresponds to the diagnostic condition determination means of the present invention.

If the timer value T3 exceeds the predetermined post-start waiting time Tout3 in step 55, C in step 53
The abnormality diagnosis of the AN signal system is permitted, and this routine ends.

As a routine for judging the operating conditions for starting the abnormality diagnosis of the CAN signal system, as shown in the flow chart of FIG. 7, in step 62, a rotation pulse signal sent from a rotation angle sensor provided in the engine is recognized. It is also possible to determine whether or not cranking has been started when the rotation pulse signal is recognized. In addition,
In FIG. 7, the routine other than step 62 is the same as the routine of FIG.

As shown in the flow chart of FIG. 8, as a routine for judging the operating conditions for starting the abnormality diagnosis of the CAN signal system, in step 72, a signal is sent to a solenoid valve of an unillustrated injector (fuel injection valve) provided in the engine. It may be determined whether or not the driving signal to be recognized is recognized, and when the driving signal is recognized, it may be determined that cranking has started. In FIG. 8, the routine other than step 72 is the same as the routine of FIG.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a control example.

FIG. 3 is a flowchart for diagnosing a reception abnormality.

FIG. 4 is a flowchart for diagnosing a reception abnormality.

FIG. 5 is a flowchart for diagnosing a reception error.

FIG. 6 is a flowchart for determining a diagnostic condition.

FIG. 7 is a flowchart for determining a diagnostic condition according to another embodiment of the present invention;

FIG. 8 is a flowchart for determining a diagnostic condition according to another embodiment of the present invention.

[Explanation of symbols]

 1 CAN signal line 2 Engine control unit 3 Transmission control unit

Claims (3)

[Claims] In a communication system of a vehicle for transmitting and receiving information between a plurality of control units via a common signal line, an interruption when the signal of the request information is not received while the end signal of the request information is not received. Interruption-time determination means for judging, reception-abnormality diagnosis means for diagnosing when the interruption time is equal to or longer than a predetermined reception abnormality determination time as a reception abnormality, and communication control with a control unit of a transmission destination at the time of the reception abnormality And a communication control canceling means for canceling the communication. 2. A vehicle communication system for transmitting and receiving information between a plurality of control units via a common signal line, wherein a required value is out of a specified range. Means, a reception abnormality diagnosis means for diagnosing a reception abnormality when the specified range excess time exceeds a predetermined reception abnormality determination time, and communication for releasing communication control with a destination control unit when the reception is abnormal. A communication control device for a vehicle, comprising: control release means; 3. The apparatus according to claim 1, further comprising: cranking time determining means for determining when the engine is cranking; and diagnostic condition determining means for not performing a diagnosis when reception is abnormal during cranking. A communication control device for a vehicle according to claim 1.