JPH0197837A - Apparatus for diagnosing vehicle - Google Patents

Abstract

PURPOSE:To synchronize a control device of a vehicle easily with communication systems of the main body of a vehicle diagnosing apparatus, by a method wherein a system corresponding to a communication system of the control device mounted on a different vehicle for each type of the device and a means to select and fix one communication system out of a plurality of communication systems on the basis of a response signal of said control device are provided in a control element of the main body. CONSTITUTION:A main body 25 of a vehicle diagnosing apparatus having a control element 28 is connected to a control device 2 mounted on a vehicle by means of a connector 24 for external connection. This main body 25 is disposed in a service station or the like. The control element 28 of this main body 25 is provided with a communication system selecting means 28a, to which the control device 2 is connected through connectors 26 and 27. Synchronization is made by first, second and third communication systems 28d-28f of this means 28a synchronously with an external clock from the control device 2 or according to a pacing system or by an internal clock, and one communication system is fixed by a communication system selecting means 28c.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vehicle diagnostic device that automatically selects a communication system of a vehicle diagnostic device main body that is synchronized with a communication system of a control device mounted on the vehicle.

[Problems to be solved by conventional techniques and inventions 1 In recent years,
The engine installed in the vehicle electronically adjusts the air-fuel ratio to LJIJ t#L, which provides comfortable drivability, purifies exhaust gas, saves fuel, and improves engine output.

Various sensors that detect engine status? If the output signals from +< or the output signals to various actuators such as injectors are not accurate, it will be difficult to control the engine accurately, resulting in decreased drivability and
This leads to deterioration of exhaust emissions or fuel efficiency, and a decrease in engine output.

In recent electronic control systems that have become more complex, even if a failure occurs in control equipment, sensors, or actuators, it is difficult to immediately determine the cause of the failure. Therefore, at a dealer's service station, etc., there is a so-called vehicle diagnostic device that can easily check the output signals from various sensors for the electronic IIJTL system, or the signals output from this electronic control device to various actuators. , the equipment of a hand computer is essential.

For example, the vehicle diagnostic device disclosed in Japanese Unexamined Patent Publication No. 58-12848 includes a technology that uses a dedicated checker to measure fuel injection pulse width, engine speed, etc., and automatically diagnoses whether idle rotation is normal or not. is disclosed.

By the way, the communication system of the control device installed in the above-mentioned vehicle has different communication methods (pace synchronization, clock synchronization, etc.) and communication speed (baud rate) depending on the model and model year. If a dedicated checker is used to diagnose the vehicle, the target models are limited, and it is necessary to prepare a number of vehicle diagnostic devices corresponding to each model, which is not only inconvenient to handle, but also inconvenient. be.

In addition, in a vehicle diagnostic device in which a plurality of communication systems are built into the control unit in order to be compatible with a variety of control devices, it is first necessary to input a model code using a keyboard and select and fix a communication system. However, as the number of compatible models increases, the number of digits in this model code increases, making it easy to operate incorrectly and causing problems in operability. Furthermore, if an incorrect model code is input, a communication system corresponding to the communication system of the control device mounted on the vehicle will not be selected, which will hinder diagnostic work.

[Object of the invention] The present invention has the following features:1. This was developed in consideration of the above circumstances, and there is no need to input the model code, and the communication system of the vehicle diagnostic device itself can be easily synchronized with the vehicle control device with a simple operation, making it easy to operate and economical. The purpose of this project is to provide a vehicle diagnostic device that can be used to diagnose vehicles.

[Means and effects for solving the problems] The present invention provides a vehicle diagnostic device that is connected to a control device mounted on a vehicle and diagnoses input/output signals of the control device. is provided with a plurality of communication systems corresponding to the communication systems of the control device, which differ for each model, and a communication system selection means for selecting and fixing one communication system from the plurality of communication systems based on a response signal of the control device. This is what is being done.

That is, when the control section of the main body of the vehicle diagnostic device is connected to the 1liIII all device mounted on the vehicle, the communication system selection means of this control section identifies the communication system of the control device and selects the communication system installed in the control section.・The system selects and fixes one communication system capable of two-way communication from among the plurality of communication systems identified, and then executes the diagnostic work.

[Embodiments of the invention] Hereinafter, the present invention will be described in detail with reference to the drawings.

The drawings show one embodiment of the present invention, and FIG. 1 is an external view of a vehicle diagnostic device connected to a vehicle control device, FIG. 2 is a block diagram of the vehicle control device and the vehicle diagnostic device, and FIG. 3 is a block diagram of the vehicle control device and the vehicle diagnostic device. 4 is a block diagram of the control section of the main body of the vehicle diagnostic apparatus, and FIG. 4 is a 70-diagram showing the vehicle diagnostic procedure.

The reference numeral 1 in the figure is a vehicle such as a car, and 2 is a control device installed in this vehicle 1 to perform air-fuel ratio control. >4 and read-only memory (ROM)
5, input interface 6, and output interface 7
are connected via a pass line 8.

Note that the ROM 5 stores in advance model codes corresponding to communication systems for each model.

In addition, a cooling water temperature sensor 9 is connected to the input interface 6.
water temperature signal T*, air-fuel ratio phytback signal λ of 02 sensor 10, intake air suspension signal Pt of intake pipe negative pressure sensor 11
Q1 Air conditioner switch 12 (77) Air conditioner operation signal 5I4a, vehicle speed signal S1 of vehicle speed sensor 13, idle operation signal SWi of idle switch 14.

Throttle opening signal Trθ of throttle opening sensor 15
, neutral operation signal S of the neutral switch 16
Wn, the rotational speed signal N of the engine rotational speed sensor 17, and the like are input.

The control unit N2 processes the various signals in accordance with the program stored in the ROM 5, and processes the various signals to the RA.
Once stored in the M4, the CPU 3 performs various arithmetic processing based on the stored data, and a control signal based on the processed data is sent to the canister via the output interface 7 and the drive circuit 18. The signal is output to the control unit @19, EGR actuator 20, idle control actuator 21, ignition coil 22, and injector 23 to control the operation of these actuators.

Further, the control device 2 is provided with an external connection connector 24, and a connector '26 provided on the vehicle diagnostic device main body (so-called hand computer) 25 connects an adapter harness 27 to the external connection connector 24. Connected via.

This vehicle diagnosis 1gi device main body 25 is provided at a dealer's service station, etc., and there is a control section 2 inside.
8, a power supply circuit 29, etc. are provided, and an indicator section 30, a display 31, a keyboard 32.
An 0N10FF operation switch 43 and the like are provided.

The control unit 28 also includes a central processing unit (CPLJ) 36 that is connected to each other via a path line 35, a read/write memory (RAM) 37, and an output input (
Ilo) boat 39, and read-only memory (RO
M) 41 is provided. Note that the CPLI 36 is provided with a clock pulse generating element 42 that outputs a synchronizing signal.

Further, the ROM 41 is housed in a memory cartridge 34 that is detachable from the vehicle diagnostic device main body 25 via a connector 33.

Further, to the input side of the I10 board 39, a diagnostic mode signal from the keyboard 32 and various control signals output from the output interface 7 of the control device 2 to the drive circuit 18 are input.

Furthermore, the output side of this I10 port 39 is connected to the input interface 6 of the control device 2 and the display 31.

Further, the power supply circuit 29 connected to the control section 28 is connected to the power supply #AvCC of the vehicle 1 via the operation switch 43 and the adapter harness 27.

On the other hand, a communication system selection section 28a is provided in the control section 28 of the vehicle diagnostic device main body 25. This communication system selection unit 28a includes a calculation unit 28b1 which is connected to each other via a path line 35, a communication system selection unit 28,
C1 first, second, and third communication systems 28d to 28f
is provided.

When the I control device 2 is synchronized with an external clock, the first communication system 28d outputs a synchronization signal from the internal clock pulse oscillation element 42 of the control unit 28 to the control device 2, and uses this synchronization signal to transmit information. It is used to synchronize and capture signals.

Further, in the second communication system 28e, the control unit H
2 reads information signals using a step-by-step method without using clock synchronization.

Further, when the control device 2 is provided with an O-sock pulse oscillation element, the third communication system 28f synchronizes the information signal with the synchronization signal from the internal clock and takes in the information signal.

Further, the arithmetic unit 28b performs arithmetic processing on the output signal from the control device 2, and outputs and displays data values on the display unit 31 or the like.

Next, the diagnostic procedure of the vehicle diagnostic device having the above configuration will be explained according to the flowchart of FIG. 4. Note that this vehicle diagnosis is performed in an actual vehicle condition.

First, connect the connector 26 of the vehicle diagnostic device main body 25 to the external connection connector 24 provided on the control device 2 of the vehicle 1, either directly or via the adapter harness 27.
Operation switch 4 provided on the vehicle diagnostic device main body 25
3 is set to ONL, . . . and initialized (steps 101 and 102).

Next, according to the control program, the communication system selection unit 28 provided in the control unit 28 of the vehicle diagnostic device main body 25
The first communication system 28d is selected in the communication system selection means 28c of a (step 103).

Then, the first communication system 28d outputs a synchronizing signal from the clock pulse oscillator 42 of the control device 2, and also outputs the model code of the communication system as an information transmission request signal rX (step 104).

Then, in step 105, it is determined whether the control device 2 has responded to the information transmission request signal TX. If there is a response, this first communication system 28d enables two-way communication, so this communication system 28d is selected and fixed, and the process jumps to step 110. Further, if there is no response from the control device 2, the process advances to step 106.

In step 106, the communication system selection means 28c
The second communication system 28e is selected in step 10.
7, from this second communication system 28e to the control device 2.
, the model code of this communication system is output as an information transmission request signal TX.

Then, in step 108, it is determined whether the control device 2 has responded to the information transmission request signal X. If there is a response, the second communication system 28e is selected and fixed, and the process jumps to step 110 described above. Also,
If there is no response, the process advances to step 109.

In this step 109, the last third communication system 28
ftfi selection is fixed, and this communication system model code is output from the third communication system 28f to the control device 2 as an information transmission request signal TX.

Then, the signals are synchronized by the internal clock of the control device 2, making bidirectional communication possible, and the process proceeds to step 110.

That is, as long as each of the communication systems described above can cover all the communication systems that differ depending on the model and year of the vehicle, it is not necessary to check the response signal in the communication system that is selected last.

In the illustrated embodiment, since the control device 2 is provided with an internal clock, bidirectional communication is performed using the third communication system 28f.

Then, from step 110 onwards, a normal vehicle diagnostic program is executed.

That is, first, the operator specifies the diagnostic mode he wants to monitor using the keyboard section 32 of the vehicle diagnostic device main body 25 (for example, if he wants to check the fuel injection pulse width, he inputs F → 1 → 2 → ENT). ). Then, the diagnosis mode is stored at a predetermined address in the RAM 37 of the control unit 28 of the vehicle diagnostic device main body 25 (step 110).
.

Next, the diagnostic mode stored in this RAM 37 is set to CP.
It is called by U36 and the contents are interpreted (step 111
).

Then, a transmission request signal TX of information corresponding to this diagnostic mode is output to the control device 2 (step 112).

Next, an information signal (for example, fuel injection pulse width) corresponding to the transmission request is received from the control device 2 to the control unit 28 via the specified communication system (step 11
3).

The control unit 28 calculates the received information and performs physical m conversion (step 114).

Then, this physical quantity converted information is displayed numerically (for example, 1,
31SeC) L/, inform the operator of the fuel injection pulse width (step 115), and step 110
Return to

Note that the present invention is not limited to the above-mentioned embodiments; for example, it is sufficient to have as many communication systems as are compatible with the model, and two, three or more types of systems may be built-in.

[Effects of the Invention] As explained above, according to the present invention, the control section of the vehicle diagnostic device main body, which connects to a control device mounted on a vehicle and diagnoses the input/output signals of this control device, has a Since a plurality of communication systems corresponding to the communication systems of the different control devices and a communication system selection means for selecting one communication system from the plurality of communication systems based on a response signal of the control device are provided, A communication system capable of two-way communication is automatically selected.

Therefore, there is no error in inputting the model code, and the communication system of the vehicle diagnostic device main body can be easily synchronized with the vehicle control device without the need for inputting the model code, thereby greatly improving operability.

Furthermore, it is economical because one diagnostic device can support multiple communication systems.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an external view of a vehicle diagnostic device connected to a vehicle control device, FIG. 2 is a block diagram of the vehicle control device and the vehicle diagnostic device, and FIG. 3 is a block diagram of the vehicle control device and the vehicle diagnostic device. 4 is a block diagram of the control section of the main body of the vehicle diagnostic apparatus, and FIG. 4 is a flowchart showing the vehicle diagnostic procedure. DESCRIPTION OF SYMBOLS 1...Vehicle, 2...Control device, 25...Vehicle diagnostic device main body, 28...Control unit, 28c...Communication system selection means 28.28d, 28e, 28f-...Communication system. Engraving of the drawings Figure 1 Figure 4 Procedures formal transcription (method) % formula % 1. Indication of the incident Patent application No. 255911 of 1988
No. 2, Title of the invention Vehicle diagnostic device 3, Relationship to the case of the person making the amendment Patent applicant address 7-2 Nishi-Shinjuku-chome, Shinjuku-ku, Tokyo Name (534) Representative of Fuji Heavy Industries Co., Ltd. 1) Shima Toshihiro 4, agent 〒160

Claims (1)

[Claims] In a vehicle diagnostic device that connects to a control device mounted on a vehicle and diagnoses input/output signals of the control device, a control section of the vehicle diagnostic device main body includes a plurality of communication systems corresponding to the communication systems of the control device, which differ depending on the model. A vehicle diagnostic device comprising: a communication system; and communication system selection means for selecting and fixing one communication system from the plurality of communication systems based on a response signal from the control device.