JP2924620B2 - Vehicle failure diagnosis device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure diagnosis apparatus for a vehicle that performs communication between a plurality of protocols between an engine control unit and a diagnostic device to diagnose a failure of the engine control unit.

[0002]

2. Description of the Related Art There is known a vehicle failure diagnosis apparatus for performing failure diagnosis of an engine control unit (hereinafter referred to as an ECU) for performing fuel injection control, ignition control, idle speed control, and the like of an engine. A diagnostic tester is used for failure diagnosis of the ECU, and various diagnostics are performed by connecting the diagnostic tester to a diagnostic connector of the ECU. The diagnostic results are displayed on a diagnostic tester and can be recorded and printed.

[0003] The ECU is required to perform a failure diagnosis of contents standardized by laws and regulations, and a diagnostic tester (hereinafter, referred to as a standard tester) having a protocol (hereinafter, referred to as a standard protocol) standardized in the automobile industry.
Connect to the diagnostic connector and perform fault diagnosis. In addition,
This standard tester is compatible with any car model from any car manufacturer. In addition, each automobile manufacturer connects a diagnostic tester (hereinafter referred to as a dedicated tester) with its own protocol (hereinafter referred to as a dedicated protocol) to the diagnostic connector of the ECU so that it can perform its own failure diagnosis. I have. The dedicated tester performs, for example, a road test in which the vehicle is actually driven to continuously collect diagnostic data. Note that this dedicated tester can communicate with the ECU using a standard protocol.

[0004] The ECU can communicate with a standard protocol and a dedicated protocol. The ECU communicates with the standard tester using the standard protocol, and communicates with the dedicated tester using the dedicated protocol or the standard protocol. Immediately after the power of the ECU is turned on, the protocol of the ECU is initialized to a standard protocol in accordance with regulations. If any communication error occurs during communication, the protocol is switched.

[0005]

In a general vehicle, when the starter is started by an ignition key to start the engine, a large current flows through the starter immediately after the start, and the power supply voltage of the battery drops instantaneously. Sometimes. When a dedicated tester starts a load test with a dedicated protocol, starting the starter to start the vehicle causes the power supply voltage of the battery to drop temporarily, so the ECU determines that power has been turned on and initializes the protocol. And switch to the standard protocol. For this reason, in the load test, a problem such as interruption of the transfer of the diagnostic data continuously sent from the ECU to the dedicated tester occurs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicular failure diagnosis apparatus in which protocol initialization is prohibited during execution of a predetermined diagnosis mode.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to FIG. 1 showing an embodiment. The present invention provides a first communication system between a diagnostic device 3 and an engine control device 1 mounted on a vehicle. A failure diagnosis device for a vehicle that performs communication according to a protocol or a second protocol and diagnoses a failure of the engine control device, wherein a protocol initialization circuit that initializes a first protocol when the power of the engine control device is turned on. ,
1c and an initialization prohibition circuit for prohibiting protocol initialization by the protocol initialization circuits 1a and 1c when the diagnostic device 3 is executing a continuous diagnostic mode for continuously collecting diagnostic data using the second protocol. 1a and 1c, thereby achieving the above object.

[0008]

When communication is performed between the diagnostic device 3 and the engine control device 1 according to the second protocol and the continuous diagnostic mode for continuously collecting diagnostic data is executed, the initialization of the protocol is prohibited. I do. As a result, even when the battery voltage temporarily drops when the starter is started and the engine control device 1 determines that the power is turned on, the initialization to the first protocol is not performed, and the collection of the diagnostic data is interrupted. Instead, the execution of the continuous diagnostic mode is continued by the second protocol.

In the means and means for solving the above problems which explain the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0010]

FIG. 1 is a functional block diagram showing the configuration of one embodiment. Engine control unit (ECU) 1
Is a microcomputer (hereinafter referred to as CPU) 1
a, an interface 1b, a memory 1c, and the like, perform fuel injection control of the engine, ignition control, idle speed control, etc., and communicate with the diagnostic testers 3 and 4 via the diagnostic connector 2. Diagnostic tester 3
Is a dedicated tester that performs a failure diagnosis of contents unique to each automobile maker, and a diagnosis tester 4 is a standard tester that performs a failure diagnosis of contents defined by laws and regulations.

The dedicated tester 3 comprises a CPU 3a, an interface 3b, a memory 3c, etc., and has a dedicated protocol defined by each automobile manufacturer and a standard protocol standardized in the automobile industry.
a, communication with the ECU 1 mounted on the vehicle and the control units 7 and 8 of other electronic systems by a dedicated protocol via the diagnostic connector 2 and the communication line 5b. The standard tester 4 has only a standard protocol standardized in the automobile industry, and uses the standard protocol via the communication line 6a, the diagnostic connector 2 and the communication line 6b.
Only communicate with.

The ECU 1 is capable of communicating with a standard protocol and a dedicated protocol, and communicates with the dedicated tester 3 using the dedicated or standard protocol.
It communicates with the standard tester 4 according to the standard protocol.
When power is supplied to the ECU 1, the protocol of the ECU 1 is initialized to a standard protocol in accordance with regulations. Also,
If any communication error occurs during communication, the protocol is switched. The memory 1c stores protocol information used during diagnosis, protocol initialization prohibition information, the number of times a communication error has occurred, and the like, and retains these memories even when power supply to the ECU 1 is stopped. ECU1
And other control units 7, 8 are batteries 9
Is supplied with power.

FIGS. 2 to 4 are flowcharts showing a communication control program executed by the CPU 1a of the ECU 1, and FIG. 5 is a flowchart showing a communication control program executed by the CPU 3a of the dedicated tester 3. The operation of the embodiment at the time of failure diagnosis by the dedicated tester 3 will be described with reference to these flowcharts. First, referring to FIGS.
The protocol initialization operation and the protocol switching operation will be described. In step S1, it is determined whether or not the power is turned on. If the power is turned on, the process proceeds to step S2; otherwise, the process proceeds to step S11. In step S2, the memory 1c
, And reads out the initialization prohibition information of the protocol, and determines whether or not the initialization is prohibited. If the initialization is prohibited, the process proceeds to step S3 to read the protocol information used in the previous diagnosis from the memory 1c and set the protocol. If the initialization is not prohibited, the process proceeds to step S4.
Go to to set the standard protocol.

In step S11, it is determined whether or not the received message has been successfully analyzed, that is, whether or not a communication error has occurred due to a difference in protocol. If no communication error has occurred, the process proceeds to step S16. If a communication error has occurred, the process proceeds to step S12. In step S12, it is determined whether or not the value n of a counter for counting the number of occurrences of communication errors is 3 or more. If a communication error has occurred 3 times or more in the past, the process proceeds to step S13; otherwise, the process proceeds to step S17. move on. If a communication error occurs three or more times in the communication with the dedicated tester 3, the current protocol is determined in step S13. If the current protocol is the dedicated protocol, the process proceeds to step S14 to switch to the standard protocol, and the current protocol is changed. If is the standard protocol, the process proceeds to step S15 to switch to the dedicated protocol. Thereafter, in step S16, the counter value n is reset to 1 and the routine returns. On the other hand, even if a communication error occurs, if the number of occurrences so far is less than three, the counter value n is incremented in step S17 and the process returns.

Next, the operation of the ECU 1 for determining the inhibition of the protocol initialization will be described with reference to FIG. In step S21, it is determined whether or not the initialization of the protocol is prohibited. If the initialization is already prohibited, the process proceeds to step S22.
If not, the process proceeds to step S27.
When the initialization of the protocol is prohibited, step S
At 22, it is determined whether or not the self-diagnosis result of the ECU 1 itself is normal. If the self-diagnosis result is normal, the process proceeds to step S23, and if not, the process proceeds to step S24. When the self-diagnosis result is normal,
In step S23, it is determined whether or not a release signal for prohibiting the initialization of the protocol is received from the dedicated tester 3. If the release signal is received, the process proceeds to step S24; otherwise, the process proceeds to step S25. In step S25, the initialization of the protocol is prohibited, and the process ends. On the other hand, when the result of the self-diagnosis is abnormal, or when a signal for canceling the initialization prohibition is received from the dedicated tester 3, the prohibition of the protocol initialization is canceled in step S24, and the process is terminated.

If it is determined in step S21 that the initialization of the protocol is not prohibited, it is determined in step S27 whether or not communication with the dedicated tester 3 is normal after the ignition is turned on. If not, the process ends. In step S28, it is determined whether the vehicle speed is equal to or greater than a preset value K. If the vehicle speed is equal to or greater than the set speed, the process proceeds to step S22; otherwise, the process ends.

Referring to FIG. 5, the operation of releasing the protocol initialization prohibition of the dedicated tester 3 will be described. In step S31, it is determined whether or not the diagnosis end button (not shown) has been operated to complete the failure diagnosis.
Go to 2 and return if not finished. In step S32, it is determined whether or not a load test end button (not shown) has been operated to end the load test. If the load test has ended, the process proceeds to step S33, otherwise returns. In step S33, a cancellation signal of the protocol initialization prohibition is transmitted to the ECU 1, and the process returns.

As described above, when a load test condition is satisfied, such as when a vehicle speed occurs during diagnostic communication, the initialization of the protocol is prohibited, and the self-diagnosis abnormality or the dedicated tester 3 is disabled.
Releases the protocol initialization prohibition when receiving a release signal from.

Although the above embodiment has been described with reference to a vehicle using an engine as a power source, the present invention can be applied to an electric vehicle. In the above embodiment, the load test is described as an example of the continuous diagnostic mode. However, the continuous diagnostic mode is not limited to the load test.

In the above embodiment, the engine control unit (ECU) 1 controls the engine control unit, the dedicated tester 3 controls the diagnostic device, and the microcomputer 1a and the memory 1c control the protocol initialization circuit and the initialization prohibition circuit. Constitute.

[0021]

As described above, according to the present invention, the initialization of the protocol is prohibited when the continuous diagnostic mode for continuously collecting the diagnostic data by the second protocol is executed. Therefore, even if the battery voltage is temporarily reduced when the starter is started and the engine control device determines that the power is turned on, the initialization to the first protocol is not performed, and the collection of the diagnostic data is performed without interruption. The execution of the continuous diagnostic mode is continued by the protocol 2.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of an embodiment.

FIG. 2 is a flowchart illustrating a protocol initialization procedure of an engine control unit.

FIG. 3 is a flowchart showing a protocol switching procedure of the engine control unit.

FIG. 4 is a flowchart showing a procedure for determining that the protocol initialization of the engine control unit is prohibited.

FIG. 5 is a flowchart showing a procedure for releasing a protocol initialization prohibition of a dedicated diagnostic tester.

[Explanation of symbols]

 Reference Signs List 1 engine control unit 1a microcomputer 1b interface 1c memory 2 diagnostic connector 3 dedicated tester 3a microcomputer 3b interface 3c memory 4 standard tester 5a, 5b, 6a, 6b communication line 7, 8 control unit 9 battery

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G05B 9/02 B60R 16/02 F02D 45/00 G01M 17/007 G05B 23/02

Claims (1)

(57) [Claims] 1. A failure diagnosis device for a vehicle that performs communication according to a first protocol or a second protocol between a diagnostic device and an engine control device mounted on a vehicle and diagnoses the failure of the engine control device. A protocol initialization circuit for initializing the first protocol when the power of the engine control device is turned on; and a continuous diagnostic mode for continuously collecting diagnostic data using the second protocol by the diagnostic device. And an initialization prohibition circuit for prohibiting the initialization of the protocol by the protocol initialization circuit.