JPS61274239A - Diagnosing apparatus for automobile - Google Patents

Abstract

PURPOSE:To eliminate the need for the operation of a selection switch in the sequential measurement for inspection items, by automatically selecting the voltage or current waveform at inspecting parts corresponding to the inspection items to make a display on a CRT. CONSTITUTION:A signal processing circuit 17 is provided between a computer 16 and a detector 10 and a signal selection circuit 18 and a CRT control circuit 19 between the computer 16 and a CRT 11. With a shift to new inspection items, first, a signal to be displayed on the CRT11 is selected in the measurement for inspection items to output a selection signal to a signal selection circuit 18 and the waveform of a corresponding signal is displayed on the CRT11 during the measurement processing (normally for several second) of the signal for the given inspection item. A separate time for observation of the display waveform is used with a limited time as for the items which require less time for the measurement processing with a short-time waveform display on the CRT11.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automobile diagnostic device that displays voltage or current waveforms at various inspection points in the electrical system of an automobile engine.

Conventional technology and its problems Conventional automobile diagnostic equipment has a function to automatically sequentially inspect each inspection item of each inspection section of the electrical system of an automobile engine in a predetermined order, and a voltage or current waveform of each inspection section. The function of the CRT (cathode ray tube) for displaying is independent, and the display items can be changed by a selection switch.

Therefore, if there is an abnormality in the results of automatic sequential inspection, it is necessary to operate the selection switch in order to display and observe the waveform of the inspected area on the CRT.

An object of the present invention is to solve the above-mentioned problems and provide an automobile inspection device that can sequentially observe waveforms of all necessary inspection parts without operating a selection switch when inspecting each inspection item one after another. be.

Means for Solving Problems The automobile diagnostic device according to the present invention includes an inspection means for automatically sequentially inspecting each inspection item of each inspection section of the electrical system of an automobile engine in a predetermined order, and an inspection section for each inspection section. In an automobile diagnostic device equipped with a CRT that displays voltage or current waveforms, 81 measurements are taken for each inspection item, and at the time of diagnosis, the voltage or current waveform of the inspection area corresponding to the inspection item at that time is automatically selected and displayed on the CRT. The device is characterized in that it is provided with a display circuit.

Embodiment Figure 1 shows the overall configuration of an automobile diagnostic device, which includes a plurality of detectors (10), a CRT for waveform display (11)
, a reference value comparison display (12), a display device (13), an operation bag @ (14), a printing device (15), and a microcomputer (16) for controlling these.

The detector (10) is for detecting the voltage, current, etc. of each part of the electrical system of the automobile engine.
Examples include a battery clip, an N depth sensor, an ignition coil secondary side voltage measuring clip, an ignition coil secondary side high voltage detection sensor, and a sensor for detecting the ignition timing of the first cylinder. CRT (1
1) is for displaying the waveform of one signal selected from the output signals of these detectors (10). A signal processing circuit (17) is provided between the computer (16) and the detector (10), and a signal processing circuit (17) is provided between the computer (16) and the CR
A signal selection circuit (18) and C
An RT control circuit (19) is provided.

The signal processing circuit (17) is a circuit that processes the output signal of the detector (10) in order to send it to the computer (16) and the signal selection circuit (18). Signal selection circuit (1
8) is a plurality of detectors (10) from a signal processing circuit (17) according to instructions from a microcomputer (16).
The CRT control circuit (19) selects one signal from the output signals of the CRT (11) and sends it to the CRT control circuit (19). ).

The reference value comparison display (12) is for relatively displaying where the measured value is for each inspection item among the reference value, upper limit value, and lower limit value. (See Figure 2). This display device (12) may be of a dot matrix type in which the display surface is divided into a matrix and can display in units of dots; for example, a dot matrix type LCD (liquid crystal) display is used.

The part near the right end of the display (12) is the position of the upper limit value of the reference value, the part near the left end is the position of the lower limit value of the reference value, and the center of the left and right sides is the position of the center of the reference value.

The display device (13) is used to display work procedures during diagnosis, and includes indicator lights that display inspection items in sequence, and tells the operator, for example, ``Turn on the ignition switch'' or ``
``Turn off the ignition switch'', ``Crank the engine'', ``Idle the engine'', ``Turn the engine to 200
It is equipped with indicator lights that instruct the driver to operate the vehicle, such as "Put in Orpm."

The operating device (14) is used to input information necessary for diagnosis into the computer (16), and includes various selection switches, push button switches, and the like.

The printing device (15) prints measurement results for each inspection item, standard values,
It is used to print out diagnostic results, etc.

The microcomputer (16) includes a CPU (central processing unit) (21), a storage device (22), and an input/output interface (23) with each of the above components.

Inspection items, reference values (upper and lower limit values) for each inspection item, measurement methods, etc. are determined in advance and stored in the storage device (
22). A program for automatically proceeding with diagnosis is also stored in the storage device (22).

In the above automobile diagnostic device, each inspection item of each inspection part of the electrical system of an automobile engine is automatically and sequentially inspected in the order stored in advance in the storage device (22) of the microcomputer (16).

When each inspection item is measured, the voltage or current waveform of the inspection area is automatically displayed on the CRT (11) for all necessary inspection items, and the measured value is displayed in comparison with the reference value. displayed on the display (12).

The measured value is displayed by one or more dots (24) on the left and right sides of the display (12) and one or more dots (24) at the top and bottom of the display (12), and the address (dot address) of the dot position representing the measured value is determined by the computer (16 ). In other words, set the dot address at the lower limit position of the display (12) to 01.
If the dot address of the upper limit position is N, the dot address of the measured value is as shown in the following formula, so the computer (1
6) can be easily implemented using the program.

(Dot address of measured value) (Measured value) - (Lower limit value) 1□×N (Upper limit value) - (Lower limit value) The table on the next page shows the inspection items and what should be displayed while measuring the item. It shows the correspondence with the displayed waveform. In the same table, waveforms are not displayed for items marked with bars.

FIG. 3 is a flowchart showing part of the automatic diagnosis process. Next, with reference to the figure, the operation of the computer (16) when inspecting cranking rotation speed, starting current, and ignition voltage among many inspection items will be explained.

In the case of checking the cranking rotation speed, first, a coil-next voltage selection signal is output to the signal selection circuit (18) (step 101). As a result, the coil-next voltage waveform is
(11) is displayed. Next, the signal processing circuit (17)
A cranking rotation speed measurement process is performed based on the output signal of a predetermined detector (10), and the measurement result is output to a reference value comparison display (12) or the like (step 102).

In the case of checking the starting current, first, a battery voltage selection signal is output to the signal selection circuit (18) (step 201). As a result, the battery voltage waveform and therefore the alternator output waveform are displayed on the CRT (11).

Next, a predetermined detector (10
) is used to perform starting current measurement processing, and the measurement results are output to a reference value comparison display (12) or the like (step 202).

In the case of checking the ignition voltage, first, a coil secondary voltage selection signal is output to the signal selection circuit (18) (step 301).
. As a result, the coil secondary voltage waveform changes to CRT (11)
will be displayed. Next, ignition voltage measurement processing is performed based on the output signal of a predetermined detector (10) from the signal processing circuit (17), and the measurement result is output to the reference value comparison display (12) or the like (step 302).

The same applies to other inspection items. That is, when moving to a new inspection item, first select the signal to be displayed on the CRT (11) during measurement of that inspection item, output the selection signal to the signal selection circuit (18), and then During signal measurement processing (usually for several seconds), the waveform of the corresponding signal is displayed on the CRT (11). Note that for items whose measurement processing takes time and whose waveforms are displayed on the CRT (it) only for a short period of time, a time limit is determined to allow time to observe the displayed waveforms.

Effects of the Invention According to the present invention, there is provided an inspection means for automatically sequentially inspecting each inspection item of each inspection section of an electrical system of an automobile engine in a predetermined order, and displaying the voltage or current waveform of each inspection section. An automobile diagnostic device equipped with a CRT is equipped with a circuit that automatically selects the voltage or current waveform of the inspection area corresponding to the inspection item at the time of measurement and diagnosis of each inspection item and displays it on the CRT. Therefore, when each inspection item is measured sequentially, the waveform of the corresponding inspection area is automatically displayed on the CRT, and there is no need to operate the selection switch, making it possible to sequentially observe the waveforms of all the necessary inspection areas. can.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a block diagram showing the overall configuration of the automobile diagnostic device, Fig. 2 is a front view showing the reference value comparison display section, and Fig. 3 is a diagram showing the automatic diagnosis processing. It is a flowchart which shows a part. (10)...Detector, (11)...CR for waveform display
T, (16)...microcomputer, (17)...
... Signal processing circuit, (18) ... Signal selection circuit, (1
9)...CRT control circuit. that's all

Claims (1)

[Scope of Claims] Inspection means for automatically sequentially inspecting each inspection item of each inspection section of an electrical system of an automobile engine in a predetermined order, and a CR for displaying the voltage or current waveform of each inspection section.
A vehicle diagnostic device equipped with a T is equipped with a circuit that automatically selects the voltage or current waveform of the inspection area corresponding to the inspection item at the time of measurement and diagnosis of each inspection item and displays it on the CRT. An automobile diagnostic device characterized by: