JPS60554B2 - Ignition system diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition system diagnostic device for an automobile, and particularly to a diagnostic device suitable for inspecting and diagnosing the status of the entire ignition system.

Generally, an ignition system has a configuration as shown in FIG.

That is, an ignition coil 3 is connected to a battery 1 whose one end is grounded via an ignition switch 2. A contact point 4 is connected to the ignition coil 3.
The edge of the pond is grounded. Further, a capacitor 5 is provided to bypass this contact point 4. A distributor 7 is connected to the secondary coil of the ignition coil, and a plug 6 is connected to the distributor 7. For example, there were diagnostic devices that measured plug discharge peak voltage, dwell angle, etc. and compared them with reference areas to indicate whether they were good or bad. However, such devices have the disadvantage that they only detect abnormal phenomena and cannot determine which part is the cause. SUMMARY OF THE INVENTION An object of the present invention is to provide a diagnostic device having a comprehensive judgment function for diagnostic results of an ignition system.

The present invention aims to measure the operating status of each device belonging to the ignition system using a minimum number of measurement points, analyze the measurement results with a data processing device, and determine and display the abnormal operation situation and the location where the abnormality is occurring. It is something. Examples will be described below.

FIG. 2 shows an embodiment of a diagnostic device for an ignition system for an internal combustion engine according to the present invention.

In the figure, the plug-side secondary voltage of the distributor 7 shown in FIG.

In addition, this plug side secondary voltage is calculated by the discharge time extraction circuit 11.
is configured to input. Further, the ignition side secondary voltage of the distributor 7 shown in FIG.
It is configured to input 0. Furthermore, it is configured to extract the primary voltage from between the contact point 4 and the ignition coil 3 and input it to each of the dwell angle extraction circuit 12, point voltage extraction circuit 13, and rotation trigger circuit 14.

Further, an advance angle extraction circuit 15 is provided to detect the advance angle of the ignition position. These are the peak value extraction circuit 10, the discharge time extraction circuit 11, the dwell angle extraction circuit 12, the point voltage extraction circuit 13, the rotation trigger circuit 14, and the advance angle extraction circuit 1.
5 are each connected to a data processing device 16, the data from each circuit is processed by this data processing device 16, and the result of processing the data is displayed on a display device 17 connected to this data processing device 16. be done.

FIG. 3 shows a detailed concrete circuit of the embodiment shown in FIG.

In the figure, voltage probes 30 and 41 are used to detect the secondary voltage on the plug side and the secondary voltage on the ignition side, for example, which are inserted between the high tension cable and the plug or on the ignition coil side.

- A voltage probe 50 formed in a clip shape at the output end of the ignition coil is used to detect the ignition primary voltage. A resistor 31 is connected to the voltage probe 3, and the input terminal of an amplifier 33 is connected to the resistor 31 via a resistor 75. Further, a resistor 32 is connected to the resistor 31, and the other end of this resistor 32 is grounded. Further, the other input terminal of the oven amplifier 33 is grounded. A switching circuit 18 is connected to the output terminal of the oven 33. Further, this obeamp 33 is fed back via a resistor 34. This obeamp 33
The output terminal of is connected to the data processing device via a buffer 69. Also, one input terminal of a comparator 49 is connected to the output terminal of this obeamp 33 via a resistor 45. It is grounded via a capacitor 46.Resistors 47 and 48 are connected to the other input terminals of the comparator 49.
is connected, and one end of the resistor 48 is grounded.
One input terminal of an AND circuit 64 is connected to the output terminal of the comparator 49. The other input terminal of the AND circuit 64 is configured to receive a clock signal from the clock generator 63. The clock input terminal CL of a counter 67 is connected to the output terminal of the AND circuit 64.
It is connected to the. The counter 67 is configured to receive an output signal from the buffer 69 at its reset input terminal. On the other hand, the voltage probe 41 includes a resistor 4.
2 are connected.

Resistors 76 and 43 are connected to the other end of the resistor 42, the input terminal of the oven amplifier 66 is connected to the other end of the resistor 76, and the other end of the resistor 43 is grounded. The output terminal of the oven amplifier 66 is connected to a switching circuit 18. This switching circuit 18 has the function of switching between the output from the oven amplifier 33 and the output from the oven amplifier 66 in response to a command 81 from the data processing device 16. It is something.
It is fed back to the input terminal of the amplifier 66 via a resistor 44. The output terminal of this switching circuit 18 has a FET 38
gates are being contested.

Further, the output terminal of the switching circuit 18 is grounded via a capacitor 35, and a switch 36 is provided to bypass this capacitor 35. This switch 36 is
It operates according to a command 83 from the data processing device 16. F
The source of ET38 includes a resistor 37 and a switch circuit 39.
is connected. The other end of the resistor 37 is grounded,
The output terminal of the switch circuit 39 is connected to the data processing device 16 via an AD converter 40. switch circuit 3
9 is configured to operate in response to a command 801 from the data processing device 16. On the other hand, voltage probe 50
Resistors 78 and 53 are connected in series, and the other end of the resistor 53 is connected to the input terminal of a comparator 57.

Further, resistors 52 and 51 are connected in series to the resistor 78 , the terminal of the resistor 51 is grounded, and the data processing device 16 is connected to the resistor 52 via a buffer 61 . Further, the resistor 53 is grounded via a capacitor 54. Resistors 55 and 56 are connected to the other input terminals of the comparator 57.
is connected, and the terminal of the resistor 56 is grounded.
A resistor 58 and an AND circuit 65 are connected to the output terminal of the comparator 57.
One input terminal of the is connected. Resistor 58 is grounded via capacitor 59. Further, a monostable multipipulator 60 is connected to the resistor 58 . The output of this monostable multipipulator 60 is the data processing device 16
is configured to input. A clock generator 63 is connected to the other input terminal of the AND circuit 65. Further, the output terminal of the AND circuit 65 is connected to the clock input terminal CL of the counter 68. The reset input terminal R of this counter 68 is configured so that the output signal of the monostable multipipulator 60 is input.
The output of counter 68 is configured to be input to data processing device 16 . On the other hand, voltage probe 5 Kawakoha,
A switch 62 follows, to which the switch circuit 39 is connected.

This switch 62 is turned on and off by a command 82 from the data processing device.The output terminal of the buffer 61 is connected to the clock input terminal of a flip-flop 70, and the output terminal Q of the flip-flop 70 is connected to the output terminal of the buffer 61.
One input terminal of the AND circuit 71 is connected to
The output terminal of the clock generator 63 is connected to the other input terminal of the AND circuit 71.

Further, the output signal of the flip-flop 70 is output to the counter 7
The clock input terminal CL of the counter 72 is configured to receive an output signal from the AND circuit 71, and the output terminal of the counter 72 is connected to the data processing device 16. There is. on the other hand,
A keyboard 74 is connected to the timing light 73 for measuring the advance angle, and a data processing device 16 is connected to the keyboard 4.Next, the operation of this embodiment will be explained.

First, a circuit consisting of resistors 45, 47, 48, capacitor 4'6, comparator 49, AND gate 64, and clock generator 63 constitutes the discharge time extraction circuit 11 shown in FIG. The fourth voltage obtained with the plug side voltage probe 30
A signal as shown in FIG. 4a is voltage-divided by resistors 31 and 32, passes through a polarity inverting circuit A formed by an amplifier 33 and resistors 75 and 34, and passes through an integrating circuit constituted by a resistor 45 and a capacitor 46. The waveform becomes as shown in FIG. 4d.

When this waveform is passed through a voltage comparator C composed of resistors 47 and 48 and an oven amplifier 49, a discharge time Td is obtained as shown in FIG. When passed through the AND gate 64, the output becomes an output signal as shown in FIG. 4e. The counter 67 uses the signal of the cylinder trigger 69 obtained through the buffer 69 from the output of the sacrificial inverting oven amplifier 33 as a reset input, and the output signal of the AND circuit 64 as a clock input as shown in FIG.
The clocks are counted for a time Td as shown in , and the counted results are output to the data processing device 16. The data processing device 16 uses, for example, a microcomputer, and is configured to read the counted value of the counter 67 after approximately 8 hS have elapsed each time a cylinder trigger is input when a discharge time processing routine is executed. Now, the count value of counter 67 is Ac
, when the clock period of the clock generator 63 is Tc, the discharge time Td is expressed as Td=Ac×TC, which is processed by the data processing device 16.

Next, measurement of the dwell angle 12 will be explained.

The signal obtained from the primary voltage probe 50 is connected to the resistors 76, 5.
2 and 51, and the voltage divided signal between resistors 68 and 52 is integrated by an integrating circuit D consisting of a resistor 53 and a capacitor 54, and the output is passed through a voltage comparator circuit E consisting of resistors 55 and 56 and an oven amplifier 57. 4, a dwell angle signal as shown in FIG. 4 is obtained.

This signal and the clock from the clock generator 63 are passed through an AND circuit 65, the output of the AND circuit 65 is passed through a counter 68 for counting, and the counted value is processed by the data processing device 16 in the same manner as when calculating the discharge time. Figure 4 4
Find the time T corresponding to the dwell angle indicated by f. On the other hand, when the signal voltage-divided by the resistors 51 and 52 is passed through the buffer 61 and the flip-flop 70, a signal (primary cycle time) shown in FIG. is passed through an AND circuit 71, counted by a counter 72 which uses this output as a clock input, and this output is input to the data device 16 to calculate time.

Now, if this time is T2, then T2 is 1/T2 engine rotational speed, and if the number of cylinders is N, it is expressed as Dokawa angle: 轡X毛, and this is processed by the data processing device 16.

Next, the peak voltage measurement method will be explained.

The output of the obeamp 33 representing the plug side secondary voltage or the obeamp 6 representing the ignition side secondary voltage
6 is selected by the switching circuit 18 based on the command 81 from the data processing device 16, and this signal is sent to the capacitor 35, switch 36, FET 38 and resistor 3.
The peak value is extracted by a peak hold circuit F consisting of 7, and its output is inputted to the data processing device 16 via a switch 39 and an AD converter 40'. The data acquisition signal uses a signal obtained by converting the output of the comparator 57 of the dwell angle detection circuit into a delay circuit consisting of an integrating circuit G consisting of a resistor 58 and a capacitor 59 and a monostable multipipe layer 60. Further, the signal for discharging the capacitor 35 is a command 83 obtained from the data processing device 16. The peak value can be found by calibrating the data obtained with the above circuit through experiments. Further, point contact voltage can also be obtained by a method similar to the above method.

The lead angle is measured using a timing light 73, and the measured value is input into the data processing device using a keyboard 74.

The data processing device 16 internally or externally stores the normal reference band for each item and the content of the cause location based on the combination of the quality of the measurement result for each item. An ignition system diagnostic device equipped with such functions runs a program that measures each item and compares the measured results with a pre-stored normal reference band to determine pass/fail.
The quality of each item is stored in the data processing device 16.

Next, the measurement results and the stored combinations of pass/fail for each item are compared with previously stored combinations, and the stored contents where all items match are displayed on the display device 17.

The memory contents based on the combination of pass/fail for each item are as follows. It is. Therefore, according to this embodiment, when an abnormality occurs in the ignition system, the abnormality can be found and its cause can be immediately determined, and the detector can be easily installed in the engine.

Furthermore, according to this embodiment, it is possible to perform a comprehensive diagnosis of the ignition system using only two or three measurement points, and moreover, the diagnostic results when an ignition system is abnormal, especially when multiple equipment is abnormal, can clearly identify the causative device. Therefore, it is possible to achieve accurate diagnosis and significantly improve recovery time.

As described above, according to the present invention, the diagnosis results of the ignition system can be comprehensively determined.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a conventional ignition circuit diagram, Fig. 2 is a block diagram of a diagnostic device showing an embodiment of the present invention, and Fig. 3 is a diagram of the embodiment shown in Fig. 2. A specific circuit diagram, FIG. 4, is a diagram showing waveforms at specific points in the circuit of FIG. 2. 10...Peak value extraction circuit, 11...Discharge time extraction circuit, 12...Dwell angle extraction circuit, 13.
...Point voltage extraction circuit, 14...Rotation trigger circuit, 15...Advance angle extraction circuit, 16...
...Data processing device, 1? ...Display device, 1
8...Switching circuit. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A plurality of detection and measurement members that detect and measure the operating status of the parts necessary to understand the operating status of ignition system equipment, and the output value from each detection and measurement member and each predetermined value. A plurality of comparison circuits that separately compare reference values at the detection location and output signals indicating the presence or absence of an abnormality, and a pre-stored abnormality cause location is detected by a combination of the signals output from each comparison circuit. 1. A diagnostic device for an ignition system, comprising: a detection means.