JPH0727598B2 - Data communication device for in-vehicle electronic control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication device for an on-vehicle electronic control device, and more particularly to a detection output of a sensor collected and accumulated in an electronic control device mounted on a vehicle and an actuator. The present invention relates to a data communication device for transmitting various data such as the command value and engine operation parameter to an external diagnostic device.

[0002]

2. Description of the Related Art As is well known, in automobiles, motorcycles and the like (hereinafter simply referred to as "vehicle"), various sensors and control actuators are attached to the vehicle, and the outputs of these sensors are mounted on the vehicle. Collected and stored in a storage device in the electronic control unit, a predetermined calculation is performed using these sensor outputs, and drive control of various vehicle control actuators is executed according to the calculation result.

Further, the output of the sensor, the drive control signal of the actuator, etc. collected and accumulated in the storage device in the electronic control unit are connected to the external diagnostic device via the connection communication line during inspection and repair or maintenance of the vehicle. Read to storage,
It is designed to be used for failure detection and maintenance of various sensors and actuators. If there is data indicating a failure of the sensor or the like, the sensor is replaced or the like according to the content of the data.

Such a data communication device is described in, for example, Japanese Patent Application Laid-Open No. 54-10810, Japanese Patent Publication No. 63-31731, and Japanese Patent Application Laid-Open No. 64-52551.

FIG. 4 shows an example of a communication form in transmitting data from an on-vehicle electronic control unit to an external diagnostic unit in a conventional device of this type. As is clear from the figure, sensor output, command value to actuator, operating state of actuator, various engine parameters indicating engine operating state.
Predetermined data such as data and fault codes are periodically transmitted at a predetermined cycle T, with a communication inactivity period interposed if necessary. In the transmission of such data, a group of data as shown in the figure is detected and collected by an electronic control unit (hereinafter also referred to as "ECU") 1 and stored in an appropriate memory. Strictly speaking, it is not necessarily a fixed cycle because it is performed after the end, but in practice it can be considered as a fixed cycle.

[0006]

Failure detection of a sensor or the like by the external diagnostic device as described above is collected by the on-vehicle electronic control device while the vehicle is operating in the specified inspection mode, and its storage is stored. Since it must be performed based on the data accumulated in the device, the electronic control device sends the external diagnostic device to the external diagnostic device while the vehicle and the on-vehicle electronic control device are operating in the specified inspection mode. If the data transfer is not performed correctly, as a matter of course, an error may occur in the detection of a sensor or component failure or in the determination of the engine operating state, and a normal sensor or component may be replaced. There is a problem that failed sensors / parts cannot be replaced.

For example, when the engine is idle,
The opening of an air amount adjusting valve (EACV) provided in the bypass passage of the throttle valve is controlled to keep the engine speed constant, but in the inspection mode of this air amount adjusting valve, the valve opening (specifically, Is a control signal duo according to the valve opening.
The tee ratio) is set to one of four predetermined modes, and parameters such as the engine speed at that time are detected. Based on this, the valve opening is controlled as set. It is determined whether or not Therefore, it is obvious that the correct inspection and judgment cannot be made if the data in the operation mode different from the specified one is taken.

In the prior art, in particular, the O ₂ sensor for detecting the complete combustion degree of fuel was often replaced by mistake. The situation will be described below with reference to FIG. (A) of the figure shows the change state of the detection output of the O ₂ sensor, and (B) shows an example of the received signal when the detection output is read to the external diagnostic device in the conventional communication mode. The x mark in the figure represents the level of the received signal (sampling value), and the waveform of (A) is also shown by a dotted line for reference.

The output of the O ₂ sensor is expected to be inverted from a high level to a low level or vice versa at a certain period Ti, but the level inversion period may be deviated from this depending on the operating state of the engine. It may end up. Times t1 and t2 in FIG. 3 (A) indicate such periods in which the level change cycle is deviated. In the conventional example, as shown in FIG. 4, all data are transmitted at the same frequency, so it is difficult to increase the transmission frequency of only certain specific data, and as a result,
_{Although the 2} sensor itself is operating normally, there is a problem that the O ₂ sensor is likely to be determined to be abnormal.

Of course, even in such a case, if the frequency of data transmission, that is, the sampling period of the O ₂ sensor output waveform is sufficiently short, the waveform or the change period can be detected with certainty. In the method of collectively transmitting data, a machine clock having an extremely high frequency is required, and there is a problem that it is difficult to realize in terms of technology and cost.

The present invention has been made to solve the above-mentioned problems, and its purpose is to reduce errors in detection of failures in sensors and parts and omissions in detection, to replace normal sensors and parts, or to detect defective sensors. -To provide a data communication device for a vehicle failure diagnosis device capable of reducing component replacement leakage as much as possible.

Another object of the present invention is to provide a data communication device of a vehicle failure diagnosis device capable of accurately detecting an output data waveform without increasing the machine clock frequency. .

[0013]

As a result of various studies on the occurrence situation of the problems of the prior art, generally, the timing (operating phase) of data collection by the on-vehicle electronic control device and the data to the external diagnostic device are generally considered. Incomplete synchronization with the data transfer timing (operating phase) causes the external diagnostic device to receive the collected data in the test mode that is not required by the external diagnostic device. If a sensor whose detection output changes rapidly is to be diagnosed, it is detected because the data transfer cycle to the external diagnostic device is too long compared to the detection output change cycle. It was found that the inability to accurately detect the output causes the problem.

According to the present invention, in order to solve the above-mentioned problems based on the above-mentioned examination results, a storage device in an electronic control unit mounted on a vehicle has the electronic control unit in an inspection mode. , And / or a flag indicating the inspection mode currently being performed by the electronic control unit is set, and when the data in the electronic control unit is transferred to the external diagnostic device, the flag is first checked to check the electronic control unit. It is characterized in that the inspection is carried out by the control device and, if necessary, the inspection mode and the synchronous operation of the electronic control device are confirmed, and then the data is read.

Further, the repeated change cycle of the data to be diagnosed which is to be transmitted to the external diagnostic apparatus is shorter than the normal data acquisition cycle, and the changed state of the data may not be correctly discriminated. At this time, the characteristic feature is that the transfer and fetch cycle of the data to be diagnosed is set shorter than that of other data.

[0016]

Before starting the transmission of the data in the electronic control unit to the external diagnostic unit, the in-execution flag and / or the inspection mode flag are read and checked so that only correct data is taken in. By doing so, it is possible to prevent erroneous data from being taken in by the external diagnostic device other than in the inspection mode requested, prevent erroneous diagnosis based on erroneous data, and The reliability can be improved.

Further, since the acquisition period of the data to be diagnosed can be shortened sufficiently without increasing the frequency of the machine clock, the change state of the data to be diagnosed can be detected accurately, and therefore, It is possible to prevent an erroneous judgment such that a normal sensor is judged to be abnormal or, on the contrary, an abnormal sensor is overlooked.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic block diagram of one embodiment of the present invention, and shows an outline of a hardware configuration of an electronic control device mounted on a vehicle to be diagnosed and an external diagnostic device connected to the electronic control device.

Referring to FIG. 1, the ECU 1 includes a CPU 1
0, a microcomputer including a ROM 11 and a RAM 12, a driver 13, an A / D converter 14
And a communication interface 15 is provided. The ECU 1 is connected to peripheral devices such as various actuators 3 and sensors 4 via connectors 16 and 17.
A flag 1 indicating the operation mode of the ECU 1 is stored in the RAM 12
2F is set.

The ECU 1 performs various controls such as ignition timing control, electronic fuel injection device (EFI), and brake control. For example, when performing EFI control, the connector 16
A fuel valve solenoid is connected as an actuator 3 to the connector 17, and a TDC sensor, an engine speed sensor, a water temperature sensor, an intake air temperature sensor, a throttle valve opening sensor, etc. are connected as sensors 4 to the connector 17. The ECU 1 may be any control as long as it controls the vehicle.

A signal input from each sensor 4 to the ECU 1 is converted into a digital signal by the A / D converter 14 and then converted into a CP signal.
Captured by U10. The signal captured by the CPU 10 is
Based on the control data stored in the ROM 11 and the RAM 12, it is processed according to the program written in the ROM 11. An instruction signal is supplied to the driver 13 according to the processing result of the CPU 10, and the driver 13 drives the actuator 3 in response to the instruction signal.

In addition to the control program, the ROM 11 also stores a program for executing various inspection modes and an identification code of the ECU 1, that is, an ECU-ID. Further, the RAM 12 stores the processing result by the CPU 10 as learning data or frozen data. This frozen data is useful as data representing the operating state of the engine when an engine malfunction occurs.

The external failure diagnosis device 2 connected to the ECU 1 includes a microcomputer including a CPU 20, a ROM 21 and a RAM 22, and a driver 23, A.
A / D converter 24 and a communication interface 25 are provided. In addition to this, the external failure diagnosis device 2 is provided with a keyboard 26 for inputting an instruction by an operator, and a display device 27 for displaying a processing result by the CPU 20, an instruction input by the operator, and the like. The keyboard 26 is provided with general numeric keys, cursor movement keys, function keys and the like. A liquid crystal display panel (LCD) can be used as the display device 27.

A test probe 6 is further connected to the failure diagnosing device 2 to add a voltage / resistance measuring function as a tester function and a test signal (constant voltage signal) output function. When the output voltage is supplied to the test probe 6 via the driver 23, the test probe 6 outputs E
The test (pseudo) signal of the sensor 4 can be supplied to the CU 1. On the other hand, the signal detected by the test probe 6 is converted into a digital signal by the A / D converter 24 and taken into the CPU 20.

The communication interface 15 of the ECU 1 and the communication interface 25 of the failure diagnosis device 2 are connected to each other via the communication line 5.
, And bidirectional digital communication is possible between the CPUs 10 and 20.

The communication line 5 from the ECU 1 to the external diagnostic device
The signal acquired via the test probe 6 and the signal obtained by the test probe 6 are processed based on the failure diagnosis program and control data stored in the ROM 21 and the RAM 22, and the processing result, that is, the failure diagnosis result is displayed on the display device 27. Is displayed in. A plurality of failure diagnosis programs are usually prepared so that failure diagnosis suitable for many vehicles can be performed. RO
M21 has a VIN (vehicle identification number) and this VIN
And a selection program for selecting the optimum one from the plurality of failure diagnosis programs based on the ECU ID (ECU identification symbol), but these are not directly related to the present invention. The description is omitted.

The VIN and the selection program are stored in the ROM card 7 and new data is stored in the RO in case the VIN is added or changed due to the production of the new model.
The M card interface 28 may be incorporated into the CPU 20. In addition, it is possible to add a failure diagnosis program by using a ROM card.

Further, the external failure diagnosis device 2 can be connected to a personal computer (not shown) to store the failure diagnosis result therein, and can be printed out if necessary. Further, the external failure diagnosis device or personal computer can be connected to a host computer via a public line, and the failure diagnosis result can be supplied and stored therein. On the contrary, the host computer can also provide necessary information, for example, the updated (upgraded) version of the failure diagnosis program or the selection program to the personal computer or the external failure diagnosis device.

According to one embodiment of the present invention, when a vehicle failure diagnosis is performed by the external diagnostic device, first, the communication interface 25 of the external diagnostic device 2 is used by the communication line 5.
Is connected to the communication interface 15 of the vehicle-mounted ECU 1,
A request command for diagnosing and verifying parts and the like is transmitted from the external diagnostic device to the ECU 1. In response to the command, the ECU 1 reads the program for the requested inspection mode from the ROM 11 (or the external diagnostic device 2), confirms that the conditions of the inspection mode are satisfied, and checks the inspection mode. RA of the in-execution flag 12F indicating that the vehicle has entered
Set it in the planned area of M12. Subsequently, a predetermined function test is executed to store various data of the test result (detection outputs of various sensors, output drive signals to actuators, various engine parameters, etc.) in the RAM 12, and the flag And the obtained various data are transmitted to the external diagnostic device 2 through the communication line 5.

The external diagnostic device 2 confirms that the vehicle-mounted ECU 1 is performing the required inspection by receiving the flag 12F, and then takes in the data to be transmitted. In this way, by synchronizing the component function inspection by the vehicle-mounted ECU 1 with the reception and reception of the inspection data by the external diagnostic device 2, the external diagnostic device 2 is mounted on the ECU 1.
Since the signals and data received and received from the diagnostic device 2 are limited to those collected at the time of the inspection mode requested by the diagnostic device 2, the error data in different inspection modes are used. It is possible to prevent erroneous diagnosis.

In FIG. 2, according to the present invention, when the data is transmitted from the vehicle-mounted ECU 1 to the external diagnostic device 2 for failure diagnosis, the transmission frequency of the diagnostic target data is increased (transmission). An example of a communication form when the cycle is shortened) is shown.
As is clear from the figure, in this example, the flag F representing the inspection mode performed by the ECU 1 is first transmitted, and subsequently the diagnostic target data A (for example, O ₂
The output data of the sensor) is sampled and transmitted at a period 2 / T which is about half the data transmission period T of the conventional example shown in FIG. Other data (for example, water temperature, outside air temperature, etc.) whose output and state change are slow and need not be transmitted frequently are compared with the conventional example at the timing of B1, B2, B3 .... Transmitted in a long cycle. The data transmitted at the timing of B1, B2, ... Is not limited to one type, and it is needless to say that a plurality of types may be transmitted at the same timing.

If the cycle T is divided into the smallest possible time slots according to the machine clock and the transmission data is assigned in units of the smallest time slot, various diagnostic target data can be obtained. The transmission frequency can be set to any degree so as to satisfy the sampling theorem.

An example of diagnosing the O ₂ sensor will be described with reference to FIG. FIG. 3C shows an example of the received signal level when the detection output of the O ₂ sensor (A in FIG. 3) is transmitted to the external diagnostic device according to the present invention. The X and Δ marks in the figure represent the level of the received signal, and the dotted line waveform shown together is the same as that in (A). As is clear from comparison with the conventional example of FIG. 1B, the sampling cycle of the detection output of the O ₂ sensor is halved, so level inversion of the same waveform can be detected without omission, and a normal sensor is erroneously anomalous. It is possible to reduce the probability of judging.

[0034]

As is apparent from the above description, according to the present invention, when data is transmitted from the on-vehicle electronic control device to the external diagnostic device in response to a request from the external diagnostic device, Before the data transmission is started, the inspection in progress flag and / or the inspection mode flag is transmitted, and the inspection / operation mode of the electronic control unit at that time operates in synchronization with the external diagnostic device side. It is checked that the data is in the required inspection / operation mode, and then the transmission data is taken in, so that it is not in the inspection mode required by the external diagnostic device. It is possible to prevent erroneous data
An erroneous diagnosis based on erroneous data can be prevented and the reliability of the diagnosis can be improved.

Further, according to the expected change speed or change state of the data to be diagnosed, the fetch cycle can be set sufficiently short without raising the frequency of the machine clock, so that the fetch of data is possible. Leakage can be prevented, and therefore, it is possible to prevent a normal sensor from being erroneously determined to be abnormal, or the abnormal sensor cannot be detected.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a communication mode in which a required cycle for capturing data to be diagnosed is set short according to the present invention.

FIG. 3 is a waveform diagram showing an output capture of an O ₂ sensor according to the present invention in comparison with that of a conventional example.

FIG. 4 is a diagram showing a conventional communication mode at the time of fetching data.

[Explanation of symbols]

1 ... Electronic control unit (ECU) 2 ... External diagnostic device
5 ... Communication line 10, 20 ... CPU 11, 21 ... ROM 12,
22 ... RAM 12F ... Flag

Claims (4)

[Claims] 1. Various sensors and actuators are connected and have a normal operation mode and an inspection mode. In the inspection mode, an output signal of the sensor and a command signal to the actuator, and A data communication device for an on-vehicle electronic control device, which collects at least one data such as an engine operating parameter and transmits the data to an external diagnostic device via a communication line, wherein the on-vehicle electronic device The control device has an operation mode flag storage means for storing a flag indicating the operation mode, and is set in the inspection mode in response to the inspection command from the external diagnostic device, and the inspection mode is set. Correspondingly predetermined data relating to the sensors and actuators and at least one of the engine operating parameters etc. are collected and together with a flag indicating the operating mode. De-vehicle electronic control apparatus characterized by transmitting to the diagnostic device - data communication device. 2. At least one of the data related to the sensor and the actuator and the engine operation parameter is transmitted through a communication line at a substantially constant cycle. Item 1. A data communication device for an on-vehicle electronic control device according to item 1. 3. The at least one of the plurality of data transmitted from the on-vehicle electronic control device to the external diagnostic device is transmitted at a shorter cycle than other transmission data. 2. The data communication device of the on-vehicle electronic control device according to 2. 4. The on-vehicle electronic device according to claim 1, wherein the on-vehicle electronic control device has a flag for confirming that the same inspection mode is being executed in synchronization with the external diagnostic device. Data communication device of control device.