JPH02110337A - Diagnostic apparatus for breakdown of vehicle - Google Patents

Abstract

PURPOSE:To make it easy to find out the cause of breakdown by a method wherein a counter is incremented by steps for generating the sequence of occurrence of the breakdown every time when the breakdown is diagnosed, a breakdown occurrence sequence storing means for storing the value of the counter at the time of the diagnosis as the breakdown is provided, and breakdown diagnosis items are displayed so that the sequence of occurrence of the breakdown is apparent. CONSTITUTION:Signals from various sensors detecting the state of each part of a vehicle are sent to CPU 3 through an input interface 2. RAM 5 is provided with a memory C for storing the sequence of occurrence of breakdown, a memory E separated by breakdown diagnosis items, etc., and various outputs are sent to a display element through an output interface 6. A counter is incremented by a step for generating the sequence of occurrence of the breakdown every time when the breakdown is diagnosed. When the result of the diagnosis as to corresponding breakdown diagnosis items shows the presence of the breakdown, the value of the counter incremented by steps is stored and the breakdown diagnosis items are displayed by a method wherein the sequence of occurrence of the breakdown is apparent. Thereby it is made easy to find out the cause of the breakdown.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a vehicle failure diagnosis device that automatically diagnoses vehicle failures and displays the type of failure using an electronic control unit.

[Conventional technology]

In recent years, the number of vehicles equipped with electronic control units with built-in computers has rapidly increased.In addition to performing various controls using the electronic control units, some of these vehicles also perform failure diagnosis. Failure diagnosis is performed based on whether signals from various sensors that detect the state of each part of the vehicle are abnormal. If a failure is diagnosed, the type of failure is displayed on the failure display device using a code number. A breakdown in a vehicle equipped with an electronic control device is beyond the control of ordinary drivers, so when a vehicle is found to have a breakdown, it is requested to be repaired by a specialist such as a dealer. The requested dealer, etc. performs the following operations on the electronic control device,
A fault code is displayed on the fault display device. You will know the type of failure by looking at the displayed failure code and perform repairs accordingly. FIG. 2 shows an example of failure occurrence. In this example, a failure of "improper fuel injection control" (fault code -6) occurs first, and then a fault of "severe air-fuel ratio failure" (fault code -3) occurs. Of course, if there is only one failure, the failure code for that failure will be displayed, but if multiple failures occur,
Conventionally, as shown in FIG. 3, fault codes were displayed in ascending order. That is, if the fault code of two faults is 6 for poor fuel injection control and 3 for severe air-fuel ratio fault, first 3 is displayed and then 6 is displayed. Note that, as a document related to a vehicle failure diagnosis device, there is, for example, Japanese Utility Model Application Publication No. 58-150184.

[Problems to be Solved by the Invention] (Problems) However, with the above-mentioned conventional vehicle fault diagnosis device that displays faults in descending order of fault codes, the order in which the faults occur cannot be determined. There is a problem in that when multiple failures occur in a chain due to a failure, it is difficult to determine the cause of the failure. (Explanation of the Problem) For example, as shown in FIG. 2, consider a case where a fuel injection control malfunction initially occurs, which causes a severe air-fuel ratio malfunction. In the conventional fault display, the fault codes are displayed in descending order as shown in Figure 3. (11) Could the fault of severe air-fuel ratio failure and the fault of fuel injection control failure have occurred due to different causes? (2) ) It is not possible to determine whether or not the failure of poor fuel injection control caused a chain reaction of failures such as severe air-fuel ratio failure.If there are two types of failures as described above, (1) It does not take much effort or time to consider (2).However, as vehicles become more sophisticated, various functions are incorporated and the number of failure diagnosis items increases, resulting in a large number of failures. A code may be displayed. In this case, it takes considerable time and effort to find the cause of the failure.The purpose of the present invention is to solve the above-mentioned problems. It is something to do.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention takes the following measures, focusing on the fact that even if many failures occur, it is easier to find the cause of the failures if the order in which they occur is known. That is, the vehicle failure diagnosis device of the present invention includes a counter that increments each time a failure is diagnosed and generates a failure occurrence order, and a counter that is provided for each failure diagnosis item and stores the value of the counter when a failure is diagnosed. The system is equipped with a fault occurrence order storage means to display fault diagnosis items so that the fault occurrence order can be understood.

[For production]

The vehicle failure diagnosis device successively diagnoses whether or not there is a failure regarding predetermined failure diagnosis items based on sensor outputs from various parts of the vehicle. The counter is incremented each time a fault is diagnosed, and functions to determine the order in which the faults occur. A failure order storage means such as a memory is provided corresponding to each failure diagnosis item. If the diagnosis result for the corresponding fault diagnosis item is "failure", the value of the incremented counter (failure occurrence order) is stored. When all the fault diagnosis items have been diagnosed, the fault diagnosis items that have been diagnosed as faulty are displayed in a manner that allows the user to see the order in which the faults occurred.

【Example】

When multiple failures occur, knowing the order in which they occur makes it easier to determine whether the failures occurred in a chain due to one cause or whether the failures occurred independently due to separate causes. Therefore, in the present invention, a ranking of failure occurrence is created, and when a failure code is displayed on a failure display device, it is displayed in such a way that it is easy to see the time when the failure occurred. Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a vehicle failure diagnosis device according to an embodiment of the present invention. In FIG. 1, 1 is an electronic control unit, 2 is an input interface, 3 is a CPU (central processing unit), 4 is a ROM (Read Only Me+*.ry>), and 5 is a RAM (Radoll Access
? Iemory), 6 is the output interface,
7 is a failure display device. The input signals are signals from various sensors that detect the state of each part of the vehicle, and are sent to the CPU 3 via the input interface 2.
sent to. The ROM 4 is for storing programs and the like for controlling the operation of the CPU 3. R.A.
M5 is provided with a memory C1 for storing the order of failure occurrence, a memo IJE for each failure diagnosis item, a failure code memory A, and the like. Various outputs are sent via the output interface 6 to a controlled unit or a display unit. One such device is the failure display device 7. Here, the fault codes are displayed in such a way that you can see the order in which they occurred. FIG. 6 shows a flowchart for explaining the present invention in detail. In the flowchart, the blocks are blocks of processing to be performed when the vehicle failure diagnosis device is reset.
Block is a block for processing performed when a failure is diagnosed, and block M is a block related to failure display. The flowchart will be explained in detail below.
~■ correspond to steps ■~■ in the flowchart of FIG. ■ Check whether the vehicle diagnostic equipment needs to be reset. The person who repaired the fault inputs a reset signal to check whether the fault has indeed been fixed after the fault is completed. If the reset signal is input, when the flow starts, the flow goes to YES in step (2), and each memory and counter is cleared. If you clear it and run the flow, and the problem still remains, then the repair was not sufficient. If the fault has disappeared, the repair is complete and the car is returned to the customer. ■ Clear all memory C for storing failure order. The reason why 1+1 memories are prepared from C(0) to C(+) is to correspond to the fact that there are i+1 failure diagnosis items, as described in the next section (2). ■ Clear all fault diagnosis item memory E. The reason why i+1 memories are prepared from E(0) to E(i) is that there are i+1 fault diagnosis items (fault codes...from 0 to i+1). This memory records a value indicating whether it is a failure or not. ■ Set the contents of the counter to 0. This counter is a counter used to generate a number representing the order of failure occurrence. ■ Set the contents of fault code memory A indicating the fault code number to 0. That is, the fault code with the smallest number is used. ■ Compare the contents of the fault code memory with i. The contents of the fault code memory A (that is, the fault code) are
”, if A is less than or equal to i, proceed to step ■ and set i
If it is larger, proceed to step @. ■ Diagnose the fault diagnosis items for fault codes. ■ Check the diagnostic results. If there is a failure, step
If there is no failure, proceed to step @. ■ Memory E for each fault diagnosis item corresponding to fault code A
(A) stores a numerical value representing a failure. As a numerical value representing a failure, for example, a value such as "1" or "2" is determined in advance. Note that the value "0" is used as a value indicating that there is no failure. [Phase] Increase the counter value by 1. (2) Store the value of the counter in the memory C (A) for storing the order of failure occurrence corresponding to the failure code A. @ 0 in which the value of fault code A is increased by 1 Next, the process moves to the fault diagnosis item corresponding to fault code A+1. @ The fact that the value of the fault code A has increased and exceeded i, that is, A=i+1, means that the diagnosis for all fault diagnosis items has been completed. Therefore, it is returned to A-0. [Phase] The steps after this step are for fault indication. First, in this step, it is determined whether or not it is normal. Check the contents of the memory E for each fault diagnosis item, and if there is even one numerical value indicating a fault (for example, "IJ"), it means that it is not normal.If all of them are r□, it is said that it is normal. ■ If all are "0", proceed to this step and a message indicating normality will be displayed. (2) Fault diagnosis items whose value in the memory E for each fault diagnosis item is not "0", that is, fault diagnosis items whose value is a numerical value representing a failure, are displayed in descending order of the value in the memory C for storing the order of failure occurrence. FIG. 4 shows an example of a failure display method using this step. As shown in Figure 2, the failure code 6 "Fuel injection control failure" occurs first.
Next, if a "severe air-fuel ratio defect" failure represented by failure code 3 occurs, rlJ, C
"2" should be stored in the memory of (3). Therefore, first 6 is displayed, then 3 is displayed. By looking at this display, specialists such as dealers working on repairs can know in what order the failures occurred, so they can check if one failure caused a chain reaction of other failures. It will be easier to guess whether it is true or not. (■ This is another method of fault display in the present invention. This method may be adopted instead of the step [phase] display method. This display method displays not only the fault code but also the order of fault occurrence. Figure 5 shows an example of fault display using this step. The faults shown in Figure 2 If this occurs, first 3
- (2) is displayed. 3 indicates a fault code for a fault diagnosis item of severe air-fuel ratio failure, and (2) indicates that this fault is the second fault that has occurred. Next, 6-(1) is displayed. 6 indicates a fault code for the fault diagnosis item "Fuel injection control failure", and (1) indicates:
This indicates that the failure is the first failure to occur. )

【Effect of the invention】

As described above, according to the vehicle failure diagnosis device of the present invention,
It has the following effects. (1) When multiple failures occur, it is possible to display the order in which they occur. (2) Therefore, it becomes easier to predict whether one failure caused a chain reaction of other failures, making it easier to find the cause. As a result, the effort and time required for repairs could be reduced.

[Brief explanation of drawings]

Fig. 1: Vehicle failure diagnosis device according to an embodiment of the present invention Fig. 2: A diagram showing one example of failure occurrence Fig. 3: Example of a conventional fault display method Figs. 4 and 5 Figure...Example of failure display method in the present inventionFigure 6...Flowchart for detailed explanation of the present invention, 1 is an electronic V control device, 2 is an input interface, 3 is a CPU, 4 is an I '? OM, 5 is RAM, 6
is an output interface, and 7 is a failure display device. 1 ■ Figure 2 Figure 4

Claims (1)

[Claims] A fault occurrence order storage means is provided for each fault diagnosis item and stores the value of the counter when a fault is diagnosed. A vehicle failure diagnosis device characterized in that diagnostic items are displayed so that the order of failure occurrence can be understood.