GB2222701A

GB2222701A - Engine diagnosis

Info

Publication number: GB2222701A
Application number: GB8916490A
Authority: GB
Inventors: Kunihiro Abe
Original assignee: Fuji Jukogyo KK; Fuji Heavy Industries Ltd
Current assignee: Subaru Corp
Priority date: 1988-07-23
Filing date: 1989-07-19
Publication date: 1990-03-14
Anticipated expiration: 2009-07-19
Also published as: GB8916490D0; JPH0235327A; DE3923937C2; DE3923937C5; JPH0827220B2; GB2222701B; DE3923937A1

Description

1 1 1 1 DIAGNOSTIC SYSTEM FOR A MOTOR VEHICLE 27 0 - I 4 The present

invention relates to a diagnostic system for a motor vehicle and a diagnostic device used therein.

Motor vehicles have recently been equipped with an electronic control system for controlling various componentsi such as fuel injectors. of the engine thereby improving driveability. exhaust gas emission. fuel consumption and engine power. The electronic control system controls the components based on information represented by output signals from various sensors arranged to detect engine operating conditions. Accordingly, if malfunction of components or sensors should occur, the engine does not properly operate. Because electronic control systems are complex, it is difficult to immediately find the source of the malfunction and a diagnostic device for easily checking the electronic control system has to be provided in auto service and repair workshops.

Japanese Patent Application Laid-Open No. 59-61740 discloses an electronic control system provided with a self-diagnostic system where signalling lamps provided on the vehicle are lit or flashed when abnormalities occur in sensors and actuators. such as injectors. However, the actual conditions of the defective sensors and actuators cannot be represented by the lamps.

2 Japanese Patent Application Laid-open No. 58-12848 discloses a diagnostic system in which an exclusive checking device is provided for measuring the pulse-duration of fuel injection and engine speed, and for checking whether idling speed is normal. The checking device is provided for diagnosing only a designated specific type of a motor vehicle.

Figure 5 of the accompanying drawings shows a recently proposed diagnostic system which comprises a diagnostic device 102 and a memory cartridge 103 detachably attached to the device 102. The memory cartridge 103 has a memory, such as a ROM, for storing diagnostic programs and fixed data for the type and the model year of a motor vehicle 100. The various cartridges 103 for all vehicle types are provided and a cartridge for the presented vehicle is selected and attached to the diagnostic device 102. A two-way communication between the cartridge 103 and an electronic control system 101 on the vehicle 100 is performed for diagnosing the electronic control system 101.

In such a vehicle, if the electronic control system 101 is improved, or the diagnosis is changed in accordance with the improvement, or diagnostic items increase owing to the addition of sensors and actuators, a different memory cartridge is needed.

However, since the ROM storing diagnostic programs and fixed data is mounted in the cartridge at 3 the manufacturing stage thereof, the data and programs cannot be rewritten at an auto service and repair workshop. Consequently, a user cannot swiftly carry out thediagnostic operation for the improved control system on the vehicle. Moreover, in order to diagnose various motor vehicles, a large number of memory cartridges for the various vehicles must be provided in the workshop and this is undesirable.

As a memory for the diagnostic device, a mask ROM or EPROM is usually employed. However, it takes a long time to fix a mask pattern for the mask ROM. When using the EPROM, it also takes much time to store many new programs. Furthermore, a totally new cartridge must be provided for every new memory, resulting in increase of the cost.

An object of the present invention is to provide a diagnostic system wherein a main program for diagnosing an electronic control system of an automotive engine of a vehicle can be easily changed in accordance with the type of a vehicle to be diagnosed without changing the memory cartridge.

According to a first aspect of the present invention, there is provided a diagnostic device for diagnosing an electronic control system of an automotive engine in a motor vehicle comprising a C.P.U.; a memory cartridge detachably connected to the diagnostic device; a first memory provided in the memory cartridge for storing a diagnostic program; a 4 second memory provided in the memory cartridge and storing a bootstrap program and means for loading a main diagnostic program stored in an outside memory on to the first memory in accordance with the bootstrap program.

The outside memory may be a floppy disk used in a computer.

According to a second aspect of the present invention, there is provided an electronic control system of an automotive engine in a motor vehicler said electronic control system having sensing means for detecting operating conditions of said motor vehicle and control means for storing input data from said sensing means and for providing output data to control said vehicle, and said diagnostic system including a device having a control unit responsive to said output data for automatically diagnosing said output data and for producing diagnostic data, display means for displaying said diagnostic data, and a keyboard for inputting a diagnostic mode into said control unit; connecting means for connecting said control unit with said electronic control system; a separate computer connected to said diagnostic device for storing a main program and a memory cartridge detachably connected to said diagnostic device for storing a diagnostic program, and wherein said memory cartridge includes means for storing a bootstrap program and means are provided for loading said main program stored in said j:

separate computer into said memory cartridge in accordance with said tbotstrap program.

In order that the invention may be more readily understood, it will now be described. by way of example only. with reference to the accompanying drawings, in which:- Figure 1 is a schematic illustration of a diagnostic system; Figures 2a and 2b show a block diagram of the system; Figure 3 is a flow chart showing an operation of the system; Figure 4 is a schematic illustration of a system employing a diagnostic device and an external memory; and Figure 5 is a schematic illustration of a conventional diagnostic system.

Referring to Figure 1. an automobile 1 is equipped with an electronic control system 2 for controlling various components of an engine E. The electronic control system 2 is connected to an external connector 24. A portable diagnostic device 25 comprising a microcomputer is housed in a case 25a and has a connector 26, to which the connector 24 of the system 2 is connected through an adapter harness 27.

6 The diagnostic device 25 has a power switch 43, a liquid crystal display 31, an indicator section 30 consisting of a plurality of indicators of LED, and a keyboard 32. A connector 33 is provided for connecting a detachable memory cartridge 34.

Referring to Figs. 2a and 2b, the electronic control system 2 comprises a central processor unit (CPU) 3, a random access memory (RAM) 4, a read only memory (ROM) 5, an input interface 6 and an output interface 7. These CPU 3, RAM 4, ROM 5, the input and output interfaces 6 and 7 are connected to each other through a bus line 8. Programs and data for controlling the engine E and fixed data such as the type of the vehicle are stored in the ROM 5. Power is supplied to the CPU 3, the input and output interfaces 6.and 7, and a driver 18 from a source BV through a constant voltage circuit 45.

The input interface 6 is applied with a coolant temperature signal Tw from a coolant temperature sensor 9, an air-fuel ratio feedback signal X from an 0 2 sensor 10, an intake-air quantity signal Q from an intake manifold quantity sensor 11, an air conditioner operating signal SWa from an air conditioner switch 12, a vehicle speed signal S from a vehicle speed sensor 13, an idling signal SWi from an idle switch 14, a throttle valve opening degree signal e from a throttle position sensor 15, a neutral positioning signal SWn from a neutral switch 16 in a tr ansmission and 7 an engine speed signal N from an engine speed sensor 17. These signals are stored in the RAM 4 after processing data in accordance with the program stored in the ROM 5. The CPU 3 produces respective control signals, which are applied to the driver 18 through the output interface 7. The driver 18 produces signals for controlling a canister controller 19 of a fuel-vapor emission control system, an EGR (exhaust gas recirculation system) actuator 20, an idling control actuator 21, ignition coils 22 and fuel injectors 23.

The driver 18 further applies signals to signaling lamps 23a. The signaling lamps 23a are provided in the electronic control system 2 for informing an abnormality in the system 2. When an abnormality is detected in the system 2 by self-diagnosis function, a corresponding trouble co(e is read out from the ROM 5 so as to turn on or flash a plurality of the lamps 23a, thereby indicating the trouble code.

The diagnostic device 25 has a control unit 28 and a power supply source 29. The control unit 28 comprises a CPU 36, a RAM 37, input/output (1/0) ports 39 and 40 and a timer 38. These elements are connected to each other through a bus line 35a. A clock pulse generator 42 is provided for generating synchronizing pulses. A RAM 41 and a ROM 44 provided in the memory cartridge 34 are connected to the bus line 35a through a bus line 35b and the connector 33. The RAM 41 is provided for storing a main program for diagnosing the control system 2 of a motor vehicle and the ROM stores a 8 particular diagnosis program and a bootstrap program, which will later be described in detail. Inputs of the 1/0 port 40 are connected to the output interface 7 of the control system 2 through connectors 24 and 26 and a harness 27 so as to receive output signals of sensors and switches 9 to 17. Outputs of the port 40 are connected to the indicator section 30. Inputs of the 1/0 port 39 are connected to the keyboard 32 for applying with a mode select signal dependent on the operation of the keyboard 32, and to the output interface 7. Outputs of the port 39 are connected to the input interface 6 and the display 31. The power source 29 for supplying the power to the CPU 36 and 1/0 ports 39 and 40 is connected to the source BV through the power switch 43.

Referring to Fig. 4, in accordance with the present invention, the diagnostic device 25 is connected through a branch connector 26a to a general purpose computer 60 as an external memory, having a floppy disk drive 70 and a floppy disk 80. Thus, the 1/0 port 390 is connected with the computer 60. Main programs for diagnosing engines of various types of the vehicle are stored in the floppy disk 80. When the diagnosis program stored in the ROM is---not used because of the change of the electronic control system 2 of the vehicle to be diagnosed or the addition of sensors and actuators. a corresponding main program stored in the 9 floppy disk 80 is loaded in the RAM 41 and the diagnosis is performed in accordance with the loaded program.

Before performing the diagnosis program, the control system 2 is connected to the diagnostic device 25 through the harness 27 and the cartridge 34 is attached to the diagnostic device 25. Further, the computer 60 is connected to the diagnostic device 25, and the floppy disk 80 is inserted in the floppy disk drive 70.

The operation of the system is described hereinafter with reference to the flowchart.of Fig. 3. The engine is started, and the following diagnosis program is performed under the running of the engine.

The power switch 43 is turned on and the ROM 44 in the cartridge 34 is selected, and the RAM 37 in the diagnosis device 25 becomes enable. Accordingly, address spaces of the CPU 36 is addressed, and a bootstrap program stored in the ROM 44 starts.

At a step 50, the 1/0 port 39 for loading the diagnosis program and the RAM 37 for storing the diagnosis program are initialized. At a step 51, a load modulate of the bootstrap program for loading the diagnosis program is transferred from the ROM 44 to the RAM 37. At a step 52, the RAM 41 in the cartridge 34 is selected instead of the ROM 44, so that all the address spaces of the CPU 36 are formed by the RAM 37 and RAM 41. Thus, the load module stored in the RAM 37 is executed to send a transfer demand signal to the computer 37 and RAM 41. Thus, the load module stored in the RAM 37 is executed to send a transfer demand signal to the computer 60, so that the diganosis program stored in the floppy disk 80 is transferred to the RAM 41. At a step 53, it is determined whether the loading of the diagnosis program is completed. if it is not, the program returns to the step 52 to continue the loading. The program goes to a step 54 when the loading is completed.

At the step 54, an interrupt vector table is adjusted. At a step 55, the program jumps.to a first stored address of the diagnosis program stored in the RAM 41 to execute it.

Thus, various programs are loaded in the RAM 41 from the external memory so that the vehicle can be diagnosed without changing the cartridge 34, even if the sensors, actuators and the control system change after the manufacturing of the electronic control system 2.

The ROM 44 may include a program for directly transferring the diagnosis program from the floppy disk 80 through an exclusive floppy disk drive without using the computer 60. The cartridge 34 may also be provided with a backup battery so that a diagnosis.-program may be directly loaded in the RAM 41 through an 1/0 interface.

From the foregoing, it will be understood that the present invention provides a diagnostic system, where a diagnosis program can be changed in accordance with changes of the type of the electronic control system, sensors, p 11 While the presently preferred embodiment of the present invention has been shown and described, it is to be understood that this di^sclosure is for the purpose of illustration and that various changes and modifications may be made without departing from the scope of the invention as set forth in the appended claims.

12

Claims

Claims:

1. A diagnostic device for diagnosing an electronic control system of an automotive engine in a motor vehicle comprising C.P.U.; memory cartridge detachably connected to the diagnostic device; a first memory provided in the memory cartridge for storing a diagnostic program; a second memory provided in the memory cartridge and storing a bootstrap program; and and means for loading a main diagnostic program stored in an outside memory on to the first memory in accordance with the bootstrap program.

2. An electronic control system of an automotive engine in a motor vehicle. said electronic control system having sensing means for detecting operating conditions of said motor vehicle and control means for storing input data from said sensing means and for providing output data to control said vehicle. and said diagnostic system including a device having a control unit responsive to said output data for automatically diagnosing said output data and for producing diagnostic data. display means for displaying said diagnostic data. and a keyboard for inputting a diagnostic mode into said control unit; 13 connecting means for connecting said control unit with said electronic control system; a separate computer connected to said diagnostic device for storing a main program and a memory cartridge detachably connected to said diagnostic device for storing a diagnostic program, and wherein said memory cartridge includes means for storing a bootstrap program and means are provided for loading said main program stored in said separate computer into said memory cartridge in accordance with said bootstrap program.

3. The diagnostic device according to claim 1. wherein said main program is stored on a floppy disk of an external computer.

4. A system for diagnosing an electronic control system of an automotive engine in a motor vehicle substantially as hereinbefore described with reference to Figures 1 to 4 of the accompanying drawings.

Published 1990 at The Patent OMCO. State House. 6d 7 t High Holburn. Loondon WC 1 R 4TP Further copies may be obtained from The Patent Omos. Sales Branch. St Mary Cray, OrpLngton. K2n,.8.RS 3RD. Printed by Multiplex techjuques ltd. St Mary Cray. Kent. Con. 1.87