JPS6216684Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a failure diagnosis device for detecting unsteady malfunctions in the electrical system of an electronic control device for an automobile.

[Prior art]

Conventionally, when servicing automobiles, such failures are diagnosed by sequentially tracing the components of the electrical system based on the failure results of the electronic control device, the experience of the mechanic, or the maintenance manual, etc., and detecting the failure. It is common to diagnose Also,
A diagnostic device called an inspection checker or tester is used when a large number of various means for electrically detecting the state of the detection area of a vehicle are used, or when the logic of control signals from the control circuit is complex. .

However, in any case, if the problem occurs regularly, it is easy to diagnose, but since automotive electronic control units are constantly used in a vibrating state, it may be caused by poor contact or half-time in the electrical circuit. There are many defects that are unsteady and lack reproducibility, such as wire breakage, and it is impossible to detect such defects, especially if the period of time is short. For example, in the case of a fuel injection system that electronically calculates and controls the amount of fuel injected into an engine as an electronic control device, malfunctions in the electrical system affect safety, exhaust purification performance, riding comfort, etc., so the probability of detecting a malfunction is increased. The need is great.

[Purpose of invention]

In view of the above points, an object of the present invention is to provide an electronic control device for an automobile consisting of a detection means, a drive control means, a class control circuit, and a wire harness connecting these. It is an object of the present invention to provide a fault diagnosis device which makes it possible to easily take out input or output signals of a control circuit even with a simple configuration in which intermediate connector means is inserted and connected between the two.

Furthermore, the purpose of this invention is to make it possible to extremely increase the probability of finding the location of a malfunction by memorizing the occurrence of a malfunction even once during the diagnosis period of the electrical system of an electrical control device, and to improve the probability of discovering the malfunction in a short period of time. By detecting the frequency of failure occurrence even if it occurs multiple times, it becomes possible to understand the failure location as well as the situation in which the failure occurs.Furthermore, it is possible to identify the failure location for each signal of the electrical control device, that is, for each electrical system. The goal is to be able to diagnose them at the same time.

〔Example〕

The present invention will be described below with reference to an embodiment shown in the drawings. FIG. 1 shows a schematic configuration of an electronic fuel injection control device as an electronic control device that calculates and controls the fuel injection amount of an engine, and 10 indicates a plurality of detection points that detect the states of a plurality of detection points of an automobile. This is a group of sensors that make up the means. Reference numeral 101 denotes an intake air amount sensor, which has a known configuration in which a sliding piece 101a slides according to the intake air amount of the engine.
01b, output side terminal 101c, ground side terminal 101
Three wire harnesses 30 with three terminals d
Electronic fuel control circuit 2 via 1,302,303
Connected to 0. Reference numeral 102 designates a throttle switch in which a fully closed contact 102a is closed when the engine throttle valve is fully closed, and a high opening contact 102b is closed when the engine throttle valve is fully opened, and is switched according to the movement of the throttle valve. It has a known configuration in which the contacts 102c are switched, and each contact is connected to the electronic fuel control circuit 20 via three wire harnesses 304, 305, and 306. Sensor group 1
0 is also equipped with various known sensors for the electronic fuel injection control device, such as a rotation sensor, a cooling water temperature sensor, and an atmospheric temperature sensor, each of which is connected to the control circuit 20 via a wire harness.Detailed explanation will be omitted. The electronic fuel control circuit 20 receives signals from the sensors 101, 102, etc. of the sensor group 10, and based on these signals, determines the amount of fuel to be supplied to the engine, that is, the opening time of the electromagnetically operated fuel injection valve 40. This is a known configuration in which the valve opening/closing drive is controlled by calculating the determined fuel amount and intermittent the current flowing to the fuel injection valve 40. The fuel injection valve 40, which serves as the drive control means, has a known configuration and is installed in the intake system of the engine, which is the part to be controlled, that is, in the intake manifold near the intake port of each cylinder of the engine. The other end of the electronic fuel control circuit 20 is connected to the positive electrode side of the vehicle battery 50 by a wire harness. Although only one fuel injection valve 40 is shown in FIG. 1, generally a plurality of fuel injection valves 40 are connected in parallel and provided corresponding to the number of cylinders of the engine. The in-vehicle battery 50 has its positive terminal connected to the electronic fuel control circuit 2 via a wire harness 399.
0 and supplies current. The negative electrode, ie, the ground side, of the battery 50 is also connected to the electronic fuel control circuit 20 via a wire harness, but is not shown.
The wire harness group 30 connects each sensor of the sensor group, the fuel injection valve 40, the in-vehicle battery 50, and the electronic fuel control circuit 20 to each wire harness 301 to 3.
99, and the wire harness group 30 and the electronic fuel control circuit 20 are connected by fitting and coupling the connector terminal 30a on the wire harness side and the connector terminal 20a on the control circuit side. Ru.

The above is the schematic configuration of the electronic fuel injection control device. Figure 2 shows the configuration when the failure diagnosis device for diagnosing failures of the electronic fuel injection control device shown in Figure 1 is connected. Remove the connector terminal 30a on the wire harness side and the connector terminal 20a on the control circuit side, and instead fit and connect one connector terminal 60a of the sub-wire harness group 60 to the connector terminal 20a on the control circuit side. The connector terminal 60b is fitted and connected to the connector terminal 30a on the wire harness side.

The sub-wire harness group 60 includes sub-wire harnesses 601a and 601a that connect the sensor group 10, the on-vehicle battery 50, and the electronic fuel control circuit 20.
02a, 603a, 64a, 605a, 606
a, ..., 699a and each of these sub-wire harnesses are sub-wire harnesses 601b, 6 which are branched within one connector terminal 60a, respectively.
02b, 603b, 604b, 605b, 606
b, ..., 699b. Note that a current detection resistor 79a is connected in series between the fuel injection valve 40 and the electronic fuel control circuit 20, and two sub-wire harnesses 690a and 690b are provided to connect the current detection resistor 79a. ing. The diagnostic circuit unit 70, which is the main part of the failure diagnostic device, includes level judgment diagnostic circuits 71, 72, 73, 74, a logic judgment diagnostic circuit 75, a current judgment diagnostic circuit 79, and the like.

The level judgment diagnostic circuit 71 has the following configuration.
71A is connected to the constant voltage side terminal 101b of the intake air amount sensor 101 via the sub wire harness 601b, and the constant voltage side is connected to the lowest reference level, which is normally selected as a value that is considered not to drop below this level. A determination circuit that compares and determines the voltage level applied to the terminal 101b, which includes resistors 71a, 71b, and 71c that provide the lowest reference level, a Zener diode 71d, and resistors 71e and 71f that divides the voltage that is applied to the constant voltage side terminal 101b. and a comparator 71g. Reference numeral 71B is a holding circuit that stores a memory indicating that there is an abnormality when the determination circuit 71A determines that it is abnormal, and includes a built-in power supply B, a resistor 71i,
71k, a transistor 71j, an SCR 71m, and a normally closed switch Sw for reset. 71
Reference numeral n designates a light emitting diode to which the output of the holding circuit 71B is supplied and serves as a display means for indicating an abnormality.
71D is connected to the determination circuit 71A and the determination circuit 71
A counter drive circuit that drives the electromagnetic counter 71E once each time A is determined to be abnormal.
Diode 71p, capacitor 71g, resistor 71
r, 71s, 71t, 71v, a comparator 71u, and a transistor 71w. Electromagnetic counter 71E
has a known structure in which the number wheel is rotated electromagnetically, and each time an abnormality occurs, the number on the number wheel is increased by one. Since this electromagnetic counter 71E generally has a function of maintaining the state once the number wheel is counted up, the electromagnetic counter 71E has the holding circuit 71B and a display means, and moreover, the electromagnetic counter 71E has the function of maintaining the state once the number wheel has counted up. The built-in power source B continues to display the light emitting diode 71n as a display means, whereas the built-in power source B is not required.

To explain the operation of the level determination diagnostic circuit 71, the voltage level applied from the electronic fuel control circuit 20 to the constant voltage side terminal 101b of the intake air amount sensor 101 of the sensor group 10 may change due to a failure such as a disconnection or short circuit.
When the value falls below the allowable value, that is, the minimum reference level determined by the judgment circuit 71A, the comparator 71g
In other words, the output of the determination circuit 71A becomes "Low" level. Therefore, the transistor of the holding circuit 71B is turned off and a potential is applied to the gate of the SCR 71m, so that the light emitting diode 71n for indicating continuity of the SCR 71m is energized by the built-in power supply B to indicate an abnormality. Once this light emitting diode 71n is energized, even if it becomes normal, the intake air amount sensor 101
Even if the voltage level to be applied to the constant voltage side terminal 101b of the terminal 101b reaches the normal level, it remains energized, and faults with poor reproducibility (that is, difficult to detect) due to disconnections, short circuits, poor connections, etc. in the electrical system. Even regular abnormalities are not overlooked, and abnormalities can be reliably detected. Further, when the output of the determination circuit 71A becomes "Low" level, the capacitor 71q of the counter drive circuit 71D is instantly charged and the comparator 71
Since the level of the inverting terminal of u decreases, the comparator 71
u becomes "High" level and transistor 71w
is turned on, the electromagnetic counter 71E is energized, the number wheel is rotated, and the displayed number increases by one. When the period during which the determination circuit 71A outputs the "Low" level is very short (that is, when the intake air amount sensor 101
(When the voltage level applied to the constant voltage side terminal 101b of the terminal becomes abnormal momentarily due to poor contact, etc.)
However, the capacitor 71q of the counter drive circuit 71D
is gradually discharged by the resistor 71r, so the level at the inverting terminal of the comparator 71U does not rise immediately, and as a result, the comparator 71U outputs a "High" level signal with a time width of more than a predetermined value, and in the event of an abnormality, The electromagnetic counter 71E can be reliably driven.

Light emitting diode 71n and electromagnetic counter 71
E continues to display when an abnormality occurs even if the diagnostic circuit unit 70 is disconnected from the electronic fuel control circuit 20 or the failure diagnosis device is removed from the electronic fuel injection control device. counter 7
1E can also display the number of abnormal signals. Although both the light emitting diode 71n and the electromagnetic counter 71E are used in this embodiment, it goes without saying that the abnormality display function can be achieved using either one of them.

The other level determination diagnostic circuits 72, 73, and 74 have almost the same configuration as the level determination diagnostic circuit described above, and a detailed explanation thereof will be omitted. However, the level judgment diagnostic circuit 73 is connected to the ground terminal 10 of the intake air amount sensor 101
Since the purpose is to detect an abnormality in the voltage level applied to terminal 101d, the voltage level of this terminal 101d is compared with the highest reference level selected to be higher than the allowable value, and this is the only point in the above level judgment. This is different from the diagnostic circuit 71.

Also, level judgment diagnostic circuits 71, 72, 73, 7
Instead of the simple comparators that determine the magnitude relationship between the input signal and the reference level, each of the determination circuits 4 is a so-called window type that can determine whether the input signal is within a set range. A comparator can also be used.

Next, the logic judgment diagnosis circuit 75 will be explained.
75A is a judgment circuit, and the throttle switch 102
Resistors 75a, 7 connected to the fully closed contact 102a of
5b, a buffer amplifier 75f including resistors 75d and 75e connected to the high opening contact 102b of the throttle switch 102, and a NAND gate 75g to which the outputs of both amplifiers 75c and 75f are input. . 75B is a holding circuit, 75n is a light emitting diode, 75D is a counter drive circuit, and 75E is an electromagnetic counter. Since they are the same, detailed explanation will be omitted.

The operation of this logic judgment diagnostic circuit 75 will be explained. When the engine throttle valve is fully closed, such as when idling, the fully closed contact 10 of the throttle switch 102
2a is closed, the potential of this contact 102a becomes a "High" level, and the buffer amplifier 75c of the determination circuit 75A also outputs a "High" level signal. When the throttle valve is opened to a high opening such as when the engine is under high load, use the throttle switch 10.
Since the second high-opening contact 102b is closed, the potential of this contact 102b becomes "High" level, and the buffer amplifier 75f of the determination circuit 75A also goes "High".
Outputs level signal. Throttle switch 10
2 is the two contacts 102a, 102 during normal operation.
b are not closed at the same time, the potential of either contact (that is, the output of either buffer amplifier) is at the "Low" level, and therefore, under normal conditions, the NAND gate 75g outputs a "High" level signal. ing. However, if a failure such as a leak or breakage occurs in the electrical system including the contacts 102a and 102b of the throttle switch 102, and even once an abnormality occurs in which both contacts 102a and 102b become "High" level, the NAND gate 75g
In other words, the determination circuit 75A generates a "Low" level signal, causes the light emitting diode 75n to display via the holding circuit 75B, and also causes the counter drive circuit 75D to
The electromagnetic counter 75E is counted up to indicate an abnormality.

Next, the current determination diagnostic circuit 79 will be explained.
79A is a determination circuit, which has the following configuration.
79a is sub wire harness 690a and 690b
This is a low resistance current detection resistor inserted and connected between the 79b is this current detection resistor 79
This is a differential amplifier having a feedback resistor 79c that amplifies the voltage generated across the a. 79d is a resistor 79e,
Comparison level determined by 79f and current detection resistor 79
A comparator that determines whether or not current is supplied to the fuel injection valve 40 by comparing the potential of one end of a, and outputs a "High" level signal during a period when no current is supplied to the fuel injection valve 40. do. 79g
compares the comparison level determined by the resistors 79h and 79i with the output of the differential amplifier 79b, and determines whether or not a current greater than a predetermined value is supplied to the current detection resistor 79a (that is, a current greater than a predetermined value is supplied to the fuel injection valve 40). The comparator determines whether the supplied current is supplied or not, and outputs a "Low" level signal when the supplied current is less than a predetermined value. 79j is a transistor to which the output of the comparator 79d is supplied via a resistor 79k;
When the output of the comparator 79d is at the "High" level, that is, during a period when no current is supplied to the fuel injection valve 40, the transistor 79j is conductive, and the comparator 79g is turned on.
The comparison level determined by the resistors 79h and 79i is lowered to the ground potential. 79B is a holding circuit, 79n is a light emitting diode, 79D is a counter drive circuit, and 79E is an electromagnetic counter, which respectively correspond to the holding circuit 71B and light emitting diode 79 of the level judgment diagnostic circuit 71 described above.
n, the counter drive circuit is the same as the electromagnetic counter 79E, and detailed explanation will be omitted.

The operation of the current determination diagnostic circuit 79 will be explained. The electronic fuel control circuit 20 calculates the amount of fuel to be supplied to the engine based on the signals from the sensor group 10,
The fuel injection valve 40 is operated for a time period corresponding to this amount of fuel.
During the time period for supplying fuel, a current is passed from the vehicle battery 50 to the current detection resistor 79a of the determination circuit 79A via the fuel injection valve 40, wire harness 390, and sub wire harness 690a. Furthermore, sub wire harness 690b
Current flows into the electronic fuel control circuit 20 through. The value of this current is detected as the voltage across the current detection resistor 79a of the determination circuit 79A, this voltage is amplified by a differential amplifier 79b at a predetermined magnification, and the amplified voltage is detected by a comparator 79g as a voltage across the current detection resistor 79a. compared to the comparison level. In the unlikely event that a failure such as a leak or poor contact occurs and the current flowing through the fuel injection valve 40 falls below a predetermined value, the output of the comparator 79g, that is, the judgment circuit 79A, becomes a "Low" level, and the The light emitting diode 75n is displayed, and the electromagnetic counter 75E is counted up via the counter drive circuit 75D to indicate an abnormality. Note that during the period when current is supplied to the fuel injection valve 40, the potential at one end of the current detection resistor 79a is approximately a low potential on the ground side, but during the period when no current is supplied to the fuel injection valve 40, the potential at one end of the resistor 79a is low. Since the potential increases, the comparator 79d of the determination circuit 79A
The comparison level of the comparator 79d is higher than the comparison level of the comparator 79h, and the comparator 79d becomes the "High" level, making the transistor 79j conductive, and lowering the comparison level of the other comparator 79h to the ground potential ("Low" level). As a result, when no current is supplied to the fuel injection valve 40, the comparator 79h is always at the "High" level and no current determination is made.

In addition, in the above embodiment, each determination diagnosis circuit 71,
Although the built-in power supplies B of the holding circuits 75, 79, 71B, 75B, and 79B are shown individually, one built-in power supply B common to each circuit may be used.

Further, in the above embodiment, the determination diagnostic circuit of the diagnostic circuit section 70 includes circuits 71, 72, 73, 74, 75, 79.
However, it goes without saying that a determination/diagnosis circuit with a similar function may be provided for the sensors (not shown) of the sensor group 10.

In addition, in the above embodiment, the holding circuit 71B of each judgment diagnosis circuit (representatively the level judgment diagnosis circuit 71) of the diagnosis circuit section 70 has a memory holding function using the SCR 71m. As shown in the figure, an R-S flip-flop may be used. In the one shown in FIG. 3, when the built-in power supply B is connected to the flip-flop by the normally closed switch SW for reset, the reset capacitor 711
The transistor 712 is turned on, the transistor 713 is turned off, and the light emitting diode 71n does not emit light. Judgment circuit 7 at the time of failure
When 1A outputs a "Low" level signal, the transistor 712 is turned off, the transistor 713 is turned on, and the light emitting diode 71n emits light to indicate an abnormality. Furthermore, it goes without saying that various other means such as a fuse memory, a magnetic tape, etc. can be used as a means for exerting the memory holding function of the holding circuit.

Furthermore, in the above embodiments, a light emitting diode and an electromagnetic counter were used as the display means, but the blinking display or frequency display can also be made by various means such as lamps, electroluminescence, liquid crystals, fluorescent display tubes, etc. It is possible.

In addition, in the above embodiment, if the circuit impedance of the electronic fuel control circuit 20 is high, such as the transmission circuit of the air-fuel ratio sensor output signal, and there is a possibility that the insertion and connection of the diagnostic circuit section 70 will have an effect, the diagnostic circuit section It is also possible to insert and connect a buffer amplifier before the determination circuits 71A, . . . of each determination diagnostic circuit 71, .

Further, in the above embodiment, since some of the sensors in the sensor group 10 may cause chattering during normal operation, each determination diagnostic circuit of the diagnostic circuit section 70 is configured as shown in FIG. Resistors 710a, 710d, 710 are installed after the determination circuit 71A (representatively the level determination diagnostic circuit 71).
e, 710f, a diode 710b, a capacitor 710c, and a comparator 710g.
F may be provided. In the case of FIG. 4, the comparator 710g does not output a "Low" level signal unless the output of the determination circuit 71A maintains the "Low" level for a certain period of time determined by the discharge time of the capacitor 710c. In the case of chattering, it is not erroneously determined to be more than that.

Furthermore, in the above embodiment, the application is applied to an electronic fuel injection control device that calculates and controls the fuel injection amount of an engine as an electronic control device for an automobile, but it is also applicable to a device that electronically controls ignition magnetism of an engine, or Needless to say, the present invention can be applied to various electronic control devices such as devices for preventing wheels from locking during braking of automobiles.

[Effect of idea]

As described above, in the present invention, input or output signals of the control circuit can be easily taken out even with a simple configuration in which the intermediate connector means is inserted and connected between the terminal of the wire harness and the terminal of the control circuit. can. Moreover, if a malfunction occurs even once during the diagnosis period of the automotive electronic control unit, it will be memorized, so the accuracy of detecting malfunctions will be greatly increased, and even abnormalities with low reproducibility in the electrical system can be detected without being overlooked. In addition, even if a defect occurs multiple times in a short period of time, the frequency of occurrence of the defect is detected, so it has the excellent effect of being able to grasp the location of the defect as well as the situation in which the defect occurs. It also has the effect that fault diagnosis can be performed simultaneously and independently for each electrical system of the electrical control device.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of an electronic control device to which the present invention is applied, Fig. 2 is a block diagram showing one embodiment of the present invention, and Figs. 3 and 4 are respectively other embodiments of the present invention. It is an electrical circuit diagram of the main part of. DESCRIPTION OF SYMBOLS 10...Sensor group forming detection means, 20...Electronic fuel control circuit forming control circuit, 30...Wire harness group, 40...Fuel injection valve forming drive control means, 60...Sub wire harness group, 71A ，
71A and 79A...determination circuit, 71B, 75
B and 79B...holding circuit, 71n, 75n and 79n...light emitting diode serving as display means,
B...Built-in power supply, 71E, 75E and 79E...
...An electromagnetic counter serving as a holding circuit means and a display means.

Claims (1)

[Claims for Utility Model Registration] A plurality of detection means for electrically detecting the states of a plurality of detection points of an automobile, and a signal for controlling the control point of the automobile based on signals from each detection means. a control circuit that outputs a signal, a drive control means that drives and controls the controlled portion based on an output signal from the control circuit, and a wire harness that connects the detection means and the drive control means with the control circuit. inserted between a terminal of the wire harness and a terminal of the control circuit,
intermediate connector means for taking out input or output signals of the control circuit; a plurality of determination circuits to which the input or output signals of the control circuit are input and detect and determine abnormalities in the electronic control device for automobiles based on the signals; a plurality of holding circuit means having a power supply and receiving the output of the judgment circuit and storing and retaining the abnormality when the judgment circuit detects and judges an abnormality; and the output of the holding circuit means is supplied to detect the abnormality. An automotive vehicle characterized by comprising: a plurality of display means for displaying a display; and a plurality of abnormality occurrence frequency detection means for receiving the output of the determination circuit and detecting the frequency of abnormality occurrence each time an abnormality occurs. Failure diagnosis device for electronic control equipment.