JPS5916011A - Diagnosing device for motorcar - Google Patents

Abstract

PURPOSE:To prevent an erroneous diagnosis due to abnormality of a sensor by providing a self-diagnosing function for diagnosing the sensor prior to a vehicle diagnosis. CONSTITUTION:A false signal generating means 11 is a means of generating a palse signal for checking the sensor and self-diagnosing function of a diagnosing device, and generates a normal signal and an abnormal signal. A switching means 12 switches the normal signal and the abnormal signal generated in a means 11 according to a command signal from a computer 4. The normal signal and abnormal signal from the false signal generating means 11 are inputted to a sensor means 3 prior to the vehicle diagnosis. Then, the computer 4 diagnoses whether the sensor means 3 detects the normal and abnormal signals from the means 11 accurately or not, and then diagnoses an objective vehicle 9 after confirming that the sensor operates normally.

Description

[Detailed Description of the Invention] The present invention relates to a diagnostic device that performs two inspections for fault diagnosis of automobiles. 1. '1' relates to the self-diagnosis function of the sensor that detects the operating state of each part of the vehicle.

As a conventional automobile diagnostic device, for example, 5 is shown in FIG.
There is a kimono to show.

In FIG. 1, the input means I manually inputs various information such as the model of the vehicle to be diagnosed, the details of the engine type 1 rare inspection (for example, one-year statutory inspection, engine failure diagnosis, etc.), and the name of the vehicle. It's useless.

For example, "keyboard".

The human power means 2 is a remote input/display device that is placed in the hands of a service person and is used to send information from the service person to the diagnostic device, and conversely display information from the diagnostic device. however.

If a display means 7, which will be described later, is provided, it is possible to omit the second display means 7 and have the input means 2 perform all display operations, although it is an auxiliary function thereof.

The sensor means 3 includes sensors installed at respective locations in order to detect the functions of each part, each part, and each system of the vehicle 9 to be diagnosed, and signals from these sensors that can be input into the computer 4. Waveform shaping and increase [1
] and a signal processing circuit that performs processing such as.

The computer 4 has at least Ilo (input/output circuit)
41. RAM/12. ROM43. It is composed of a CPU 44, which performs overall control, calculations and judgments, and also controls peripheral input/output devices (2.5.6.7.8).

The diagnostic procedure storage means 5 stores, for example, contents and instruction procedures to be given to a service person in order to diagnose the function of the ignition system or the function of the fuel system of the engine, and how to judge the actually input signal. A procedure for diagnosing is also stored, and the CPU 44 of the computer 4 issues commands to control peripheral devices in accordance with this procedure.

The reference value storage means 6 stores reference values such as normal, failure, and caution for each car model and engine type. A diagnosis is made by comparing the value measured in step 3 with the reference value.

The display means 7 generally uses a CRT (cathode ray tube display), and uses two devices to project the content to be displayed to the service personnel. For example, the contents input through the input means 1, the contents of instructions given to the service person, the measured values, and the diagnostic results are displayed. Note that if the displayable range of the input means 2 is wide, this is also done.

The recording means 8 is capable of heart copying, such as a printer, and prints out the measurement value 2 diagnosis results and vehicle information as necessary. Next, typical operations using the apparatus shown in FIG. 1 and operation of the apparatus will be explained according to flowchart 1 of FIG. 2.

First, the power of the diagnostic device is turned on to start diagnosis, and the vehicle information (for example, registration number, etc.) and the required diagnosis type are input using the manual means 1 at Pl.

Next, use F2 to attach the sensor.

Sensors include high-voltage probes that detect ignition voltage, current probes that can detect the current flowing in a line by pinching it, pressure sensors that detect the pressure of engine intake and exhaust pipes, cylinders, various engine control devices, etc., and direct electrical wiring. 1. Necessary items are prepared depending on the diagnostic function, such as a clip that detects voltage by biting the terminal.

When the sensor installation is completed, the service person inputs the fact using the manual means 2 (Pa). computer 4
9 extracts a diagnostic procedure judged to be necessary from the diagnostic procedure storage means 5, and thereafter processes according to its contents. As an example, diagnosis of ignition advance angle will be explained.

At mass P4, computer 4 performs 2 according to the contents of the diagnostic procedure.
The display means 7 displays the following message: ``Up to 22 rotations at 2000 rpm''. The serviceman follows the display and steps on the accelerator to bring the engine to 2000 rpm. The engine rotation speed may be checked with the car's tachometer or monitored and displayed using a diagnostic device.

When the speed reaches 200 Orpm, the service person inputs this information to the combination 4 using the manual means 2 (P5). With this input, the signals from the dead center detection sensor and the ignition timing sensor of the sensor means 3 are taken in, the 9 ignition advance angle is calculated, and the result is temporarily stored in the RAM 42 (Pa: Next, the reference value storage means 6 The standard value corresponding to the vehicle to be diagnosed and the engine type is extracted.This standard value is compared with the value previously stored in the RAM 42, and the results are divided into normal, faulty, 11 points, etc. (P7). If a failure is determined here, the failure location, system, etc. is diagnosed from the measured value and information such as the values of other sensors, and displayed on the 5 indicator stage 7 (P9)
. In order to diagnose this failure part, it is necessary to store information for 5 diagnosis in the configuration shown in FIG.

Next, use PIQ to determine whether there is a failure or whether there is a problem with subsequent diagnosis.

If there is a malfunction or there is a problem with further diagnosis, have it repaired by a service person at that time, and then perform the diagnosis again.

If there is no need to repair immediately, pass the repair.

Next, we perform the prescribed diagnoses one after another. Of course, if it is normal, the next diagnosis is performed. In this way, nine diagnoses are performed according to the procedures prepared in the diagnostic procedure storage means 5, and when all the prepared diagnoses are completed, the display means 7 displays C.
Necessary data such as the measurement values and diagnosis results that have been performed up to now are displayed on the RT and printed on the printer of the recording means 8 (Pa).

1- As mentioned above, the conventional diagnostic device does not have a function to self-diagnose whether the sensor means 3 is normal or not, so mechanical or electrical failure of the sensor, malfunction of harness, connector, etc. Even if there is.

There were many things that were not clear, and as a result, there was a risk of misdiagnosing something normal as abnormal.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an automobile diagnostic device having a function of self-diagnosing a sensor prior to vehicle diagnosis.

In the present invention, in order to achieve the above objective.

A pseudo signal having a normal value and a pseudo signal having an abnormal value are switched and applied to the sensor, and the sensor signal at that time is compared with a reference value to accurately determine whether the sensor means is normal or abnormal. It is configured as follows.

The present invention will be described in detail below with reference to the drawings.

FIG. 3 is a block diagram of an embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same parts.

In FIG. 3, reference numeral 11 indicates a pseudo signal generating means, and reference numeral 12 indicates a switch means, which are connected so that the output of the switch means 12 is given to the sensor means 3 instead of the vehicle 9 to be diagnosed.

The pseudo signal generating means 11 is a means for generating a pseudo signal for checking the sensor and diagnostic function of one diagnostic device,
This pseudo signal consists of two signals: a normal value (hereinafter referred to as a normal signal) and an abnormal value (hereinafter referred to as an abnormal signal).

The switch means 12 switches between a normal signal and an abnormal signal generated by the pseudo signal generating means 11 in response to a command signal from the computer 4, and is composed of semiconductor analog switches, relays, etc. .

Further, if the sensor of the sensor means 3 is a sensor that detects an electric signal, it may be connected to detect the output of the switch means 12 as it is, but if it detects something other than an electric quantity, such as a pressure sensor.

It is necessary to apply the output of the switch means 12 to a suitable actuator and convert it into a physical quantity corresponding to the sensor.

FIG. 4 shows the pseudo signal generating means 11 and the Swiss-Sochi means 12.
FIG. 2 is a circuit diagram of an embodiment of the present invention.

In FIG. 1, the pseudo signal generating means 11 consists of a signal generating circuit 111 that outputs a voltage signal and a signal generating circuit 112 that outputs a phraseless signal.゛The signal generation circuit 111 is composed of a reference power source E (mercury battery or constant voltage power source) and resistors r1 to r4.
Abnormal words with E °ゝJ゛8...11.8...'' rl
(r2+r3+r4)+r2 (has a value of 5. Also, the signal generation circuit 112 outputs the wide normal signal SN2 of Noculus II. 4 pulse oscillator 113 and the pulse oscillator 114 that outputs the narrow abnormal signal SA2 of pulse +1 It is composed of.

The switch means 12 consists of two changeover switches SW, SW2 that are switched in response to a command signal.

Further, in the sensor means 3, 81. s2 is a sensor.

31 and 32 are signal processing circuits.

Next, selection of the normal signal SNI and the abnormal signal SAI will be explained.

This is a diagram showing the standard, and shows the case where it is determined to be normal when the voltage is higher than a certain level.

When determining normality or abnormality using conventional diagnostic methods, the value of C is selected as the reference value for 9 diagnoses. That is, the voltage is C
If it is above, it is determined to be normal, and if it is less than C, it is determined to be abnormal.

The reason for this is to take into account variations in the part to be diagnosed and variations in the fit of the diagnostic equipment.

In other words, if the design standard value A is the lowest value that is considered normal at the design stage of the part to be diagnosed, then the manufacturing 9
Variations occur due to assembly, temperature changes, deterioration, etc. This variation in the part to be diagnosed is referred to as "variation". Similarly, there is variation on the diagnostic equipment side, and if this is called variation 2, the standard value for 2 diagnosis is the value obtained by subtracting the value obtained by adding variation 1 and variation 2 from the design standard value A, that is, C, which is still negative. Considering the variation only in the direction (abnormal side) is more likely to avoid misdiagnosing normality as abnormality than in determining abnormality as normal211. In addition, in the case of a three-value judgment of normal, caution required, and abnormality, rather than the binary value of normal and abnormal, 01 or more is normal, less than C', C or less is caution required, and less than C is abnormal. However, C' is a fluctuation of I on the plus side.

In the conventional diagnostic method, the value of C was used as the reference value for diagnosis as described in ``5.'', but in the case of the present invention, the signal (of this) of the pseudo signal generating means 11 is negligible. Since you can directly store a small \) in the sensor,
It is not necessary to include the deviation (of the part to be diagnosed). Therefore, the reference value for diagnosis may be the value B.

Therefore, in order to determine whether the sensor is normal or abnormal with good accuracy < I11, the values of the normal signal SNI and the abnormal signal SAI should be set to values very close to the value of B (f is good). In other words, if δ is an infinitesimal value, then 1, SNI”B+δ.

5AI-B-δ.

If the output of the sensor is less than the reference value B when the normal signal SNI is given, and the output of the sensor is less than the reference value B when the abnormal signal SA is given, then the sensor is normal.

Next, the operation of sensor diagnosis will be explained.

Diagnosis of the sensor is performed in the flowchart of Figure 2.
It is best to do this before P3. For example, as shown by the broken line in FIG.
Insert.

This check program runs in ROM43 in CPUJ.
Alternatively, it is stored in the diagnostic procedure storage means 5 in advance.

FIG. 6 is an embodiment of the check program described in "-".

The program in Figure 6 is for sensor installation (P2 in Figure 2).
It starts when the service person inputs the fact that the process has ended using the input means 2, or it outputs a signal to notify that when it is properly installed, as is the case with some commercially available sensors. It starts when the computer 4 inputs and recognizes the signal.

” When the check start conditions as described in 1 are satisfied.

The computer 4 has a ROM 43 or a diagnostic procedure storage means 5.
It operates according to the procedures stored in.

First, at P21, a command signal is output, and the Swiss/Sochi means l2
Switch SW1 to the normal signal SNI side.

Next, at F22, the voltage value V detected by the sensor S at this time
Read the NI and store it at a specified location in the RAM 42.

Next, at F23, read the reference value VRI (corresponding to B in Fig. 5) corresponding to the sensor SI, and at F24, read the reference value VRI (corresponding to B in Fig.
and Vl(] are compared.

At this time, a normal signal is being input, so
If VNI>VILI (normal), set flag F to 1
F25) If VNI<VAI (abnormal), flag F.

Set to 0 (F26).

Next, in F27, the switch SWl of the switch means 12 is switched to the abnormal signal SAI side, and in F28, the voltage value VAI detected by the sensor S1 at this time is read.

Next, the reference value Vat corresponding to the sensor S1 is read at F29, and VAI and VRI are compared at pao.

At this time, an abnormal signal is input, so
VlA+<VILI (abnormal, i.e. sensor is normal)
If so, set flag F2 to 1 F31)l Vhl>
If Vnl (normal, that is, the sensor is abnormal), the flag F2 is set to 0 (F32).

Next, all the sensors 82 to SN are checked in the same manner as described in -1- (F33).

Next, at F34, the logical product of flags F1 and F2 is F=F,
・Find F2.

If flags F1 and F2 are 0 at least once, that is, if an abnormal value appears when a normal signal is input, or if a normal value appears even once when an abnormal signal is input, 'F=O, indicating that one of the sensors is abnormal. Also, if Fl and F2 are all 1, F=1,
Indicates that all sensors are normal. Therefore F=
], F35 displays ``Normal'', and when F=0, F36 displays ``Abnormal''. In the above embodiment, after checking all sensors, it displays whether they are normal or abnormal. This has the advantage of being simple since only two flags, Fl and F2, are required.

In addition, the display of normal or abnormal may be performed each time each sensor is checked, or the second display may be performed after all sensors have been checked, but separate flags are provided for each sensor, and in the case of abnormality, The sensor may be displayed. In this way, the number of flags is the number of sensors x 2
Although only one sensor is required, abnormal sensors can be immediately identified.

It has the advantage of being practical.

Further, in FIG. 4, a sensor S2 is a sensor that detects a pulse signal, for example, a pulse that drives an injection valve of an electronically controlled fuel injection device. Even in this case, the reference pulse rl
The normal signal SN2 with a slightly wider pulse rlJ and the abnormal signal SA2 with a slightly narrower pulse [IJ] may be detected by the sensor S2 and compared with the reference pulse [11].

As explained above, according to the present invention, two types of pseudo signals, a normal signal with a value on the slightly normal side of the standard value for one diagnosis, and an abnormal signal with a value on the slightly abnormal side are switched, and the IJ is sent to the sensor.
Well, it's configured to compare the sensor output at that time with the base piece 1 value.

It is possible to accurately determine whether the sensor is normal or abnormal, and there is an effect that errors in the original diagnosis result due to sensor abnormality will not occur.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an example of a conventional diagnostic device. Fig. 2 is an example of a diagnostic flowchart, Fig. 3 is a block diagram of an embodiment of the invention, Fig. 4 is a circuit diagram of an embodiment of the invention, and Fig. 5 is a pseudo signal and reference of the invention. FIG. 6, which is a diagram showing a method of setting values, is an embodiment of a flowchart of sensor diagnosis according to the present invention. Explanation of symbols 1...Input means 2...Input means 3...Sensor means 4...Computer 5...Diagnostic procedure storage means 6...Reference value storage means 7...Display means 8. ...Recording means 9...Diagnosed vehicle 11...Pseudo signal generation means 12...Switch means 31.32...Signal processing circuit 41...Ilo 42...RAM
43...ROM 44...CPU81
, S2...Sensor agent patent attorney Junnosuke Nakamura? 2 Figure 1'3 Figure J4P4 Figure

Claims (1)

[Scope of Claims] 1. Sensor means for detecting the operating state of each part of the vehicle to be diagnosed; 9. Input means for inputting various information necessary for diagnosis; 2. Diagnostic procedure storage means for storing diagnostic procedures in advance; There is a reference value storage means for storing various reference values as reference values for diagnosis in advance, and a diagnosis is made based on whether the signal of the sensor means indicated by -1 is within the normal range indicated by the reference value indicated by "2". 9 A means for determining the presence or absence of a malfunction in the vehicle and the location of the malfunction, and a display means for displaying the judgment result and contents of instructions for the diagnostic tool. In an automobile diagnostic device that performs diagnosis, a pseudo signal generating means for sending out two types of pseudo signals, a normal signal having a value on the normal side of a predetermined reference value and an abnormal signal having a value on the abnormal side; a switch means for alternately switching two types of pseudo signals and applying them to the sensor means, and storing in the diagnostic procedure storage means 9, prior to normal diagnostic operation, the output of the sensor means when a normal signal is input and the reference value. By storing in advance a procedure for determining whether the sensor means is normal or abnormal by comparing the output of the sensor means when a value and an abnormal signal are input with a reference value, it is possible to determine whether the sensor means is good or not before normal diagnostic operations. A diagnostic device for an automobile, characterized in that it is configured to self-diagnose. 2 The predetermined reference value mentioned above is set to a value that is biased toward the abnormal side by the amount of variation in the sensor signal processing system of the diagnostic device from the design standard value of the part to be diagnosed, and the normal signal is more normal than the reference value described in 2. The automobile diagnostic device according to claim 1, wherein the abnormal signal is set to a value that is shifted by a minute value to the abnormal side from the reference value. 3. If the output of the sensor means is determined to be normal when a normal signal is input, flag F is set to 1. If it is determined that there is an abnormality, the flag F is set to O, and if the output of the sensor means is determined to be abnormal when an abnormal signal is input, the flag F2 is set to 1. If it is determined to be normal, set flag F2 to O, and set flags F1 and F2.
3. The automatic small-use diagnostic device according to claim 1, wherein the sensor means indicates that the sensor means is normal when the logical product is 1, and indicates that the sensor means is abnormal when the AND is 0. 4. The above-mentioned flags F1 and F2 are judged for all the sensor means, and the logical product of all the flags is calculated, and if the result is 1, it is displayed as normal, and if the result is 0, it is displayed as abnormal. Automotive diagnostic device according to scope 3. 5-1] The flags F1 and F2 are judged for all sensor means, and the AND of all the flags is calculated. If the result is 1, it is displayed as normal, and if the result is 0, the sensor means is judged to be abnormal. The automobile diagnostic device according to claim 3, characterized in that the diagnostic device displays: