CN202974664U

CN202974664U - Fault diagnostic apparatus for vehicle diesel engine

Info

Publication number: CN202974664U
Application number: CN 201220637731
Authority: CN
Inventors: 秦文虎; 苏国辉
Original assignee: NANJING ZHIZHUO TECHNOLOGY Co Ltd
Current assignee: NANJING ZHIZHUO TECHNOLOGY Co Ltd
Priority date: 2012-11-27
Filing date: 2012-11-27
Publication date: 2013-06-05
Anticipated expiration: 2022-11-27

Abstract

The utility model discloses a fault diagnostic apparatus for a vehicle diesel engine. The fault diagnostic apparatus comprises a general data diagnosis interface OBD, a USB interface and a mainboard circuit, wherein the general data diagnosis interface OBD is connected with a vehicle electronic control unit ECU and an SCR post-treatment urea solution injection control unit DCU, and the USB interface is connected with a diagnosis computer; and the mainboard circuit comprises a CAN bus interface unit, a K-line interface unit, an ARM7 core processor and a serial-to-USB unit, the general data diagnosis interface OBD is connected to the ARM7 core processor by the CAN bus interface unit and the K-line interface unit, and the ARM7 core processor is connected with the USB interface through the serial-to-USB unit. The fault diagnostic apparatus provided by the utility model is used for monitoring vehicle faults, and displaying and modifying vehicle data parameters, solving the problems of single diagnosis protocol, poor diagnosis interface compatibility and nonsupport of a post treatment system of the conventional fault diagnostic apparatus.

Description

A kind of failure diagnostic apparatus of automotive Diesel engine

Technical field

The utility model belongs to technical field of automotive electronics, is used for the fault of monitoring diesel-engined vehicle, shows and revises vehicle data, is a kind of failure diagnostic apparatus of automotive Diesel engine.

Background technology

Keep in China's economy under the environment of fast and stable development, automobile industry has welcome a brand-new developing stage.Family-sized car enters family just on a large scale, mainly use gasoline different as power resources from kart in the past, because the moment of torsion of diesel vehicle is large, fuel-efficient, easy to maintenance, full-sized car, bus, part SUV and car use diesel oil as power resources, and repairing has also become the closely-related hot issue of living with people.For satisfying people's needs that repair, auto repair just develops to mass type from scalar type, for people provide high-quality maintenance service, incorporate our live and work along with automobile, the fault diagnosis of vehicle has become the hot issue of current industrial circle and academia's research and development.

yet, widespread use along with auto electronic control technology on automobile, ECU (Electrical Control Unit) ECU on automobile (Electronic Control Unit), SCR aftertreatment urea solution jet control module DCU and electronic component are more and more, the height electronization of automotive control system, automobile electric control system increasingly sophisticated, add in the last few years improving constantly for automobile exhaust emission standard in the world, the vehicle exhaust after-treatment system is indispensable, bring increasing difficulty to auto repair work, requirement to the auto repair technician is more and more higher, also more and more higher with the requirement of maintenance equipment needed thereby to the automobile ECU malfunction monitoring.Although increase gradually in the exploitation aspect vehicle diagnosis and maintenance system both at home and abroad, but the domestic automobile maintenance industry still exists following problem: the most of overseas equipment that adopts of malfunction monitoring maintenance of equipment, and equipment is all English operation interface basically and used in a large number the extremely English abbreviation of specialty, can't use the monitoring equipment of external complexity without the maintainer of Special Training.

In present Hyundai Motor, all adopted ECU and the DCU of some, a large amount of sensors and various actuating unit and have certain fault self-diagnosis function are distributing in this automobile that has adopted ECU and DCU.ECU and DCU can constantly monitor the working condition of each ingredient of electronic control system in car running process, if any extremely, judge concrete fault according to specific algorithm, and store with code form, start simultaneously corresponding failure operation module, out of order automobile can in time be repaired, and the maintenance personal can utilize the vehicle failure self-diagnostic function to access diagnostic trouble code, fast fault is positioned and repairs.For the convenience of producing and keeping in repair, car manufactures has added special communication interface as the vehicle diagnosis interface in these have the automobile of ECU and DCU.By this vehicle diagnosis interface, can merge corresponding vehicle diagnosis protocol development and be used for all types of fault detection systems for automobile.And in existing diagnostic device or diagnostic system, mostly be greatly embedded diagnostic device, and the following problem of ubiquity:

1) diagnosing protocol is single: be directed to diagnosing protocol, each automatically controlled manufacturer all formulates own special-purpose diagnosing protocol, is exclusively used in own exclusive ECU (Electrical Control Unit), and a kind of diagnostic device can only be used for the diagnosis of same ECU (Electrical Control Unit).General diagnostic equipment is only supported single diagnosing protocol and is not had upgrading to expand the diagnosing protocol function.

2) diagnose interface poor compatibility: existing diagnostic device mostly only has the K bus interface or only has the CAN bus interface, and adopts the RS232 interface to communicate by letter with host computer, and now a lot of notebook computer has all been abandoned serial ports, and uses USB interface instead, supports hot plug.

3) almost do not support the DCU fault diagnosis functions: along with the announcement of state's 4 emission standards, motor vehicle exhaust emission also becomes an important index, so the failure diagnostic apparatus increase supports the function of DCU to seem extremely urgent.

Summary of the invention

Problem to be solved in the utility model is: a kind of vehicle failure that is used for monitoring is provided, show and revise the automotive diagnostic installation of vehicle data parameter,, diagnose interface poor compatibility single with the diagnosing protocol that solves existing automotive diagnostic installation, do not support the problem of after-treatment system.

The technical solution of the utility model is: a kind of failure diagnostic apparatus of automotive Diesel engine, comprise conventional data diagnose interface OBD, USB interface and motherboard circuit, data diagnosis interface OBD is connected with ECU (Electrical Control Unit) ECU and the SCR aftertreatment urea solution jet control module DCU of automobile, and USB interface is connected with diagnosis computer; Motherboard circuit comprises that CAN Bus Interface Unit, K line interface unit, ARM7 core processor and serial ports turn usb interface unit, data diagnosis interface OBD is connected to the ARM7 core processor by CAN Bus Interface Unit and K line interface unit respectively, and the ARM7 core processor turns usb interface unit by serial ports and connects USB interface.

Motherboard circuit also is provided with power supply monitoring and administrative unit and firmware downloads interface, and power management is connected respectively the ARM7 core processor with monitoring means, firmware downloads interface.

Automobile fault diagnostic apparatus is called for short OBDII, interface section of the present utility model comprises automobile OBD special purpose interface and USB interface, has set up a diagnosis computer to the full duplex channel of the data communication of automobile ECU and DCU.Wherein in the CAN Bus Interface Unit CAN message being responsible for ECU and DCU are put forward, useful data extract and send to the ARM7 core processor, also the data that the ARM7 core processor will send can be packaged into the form that meets the CAN message simultaneously and send to the CAN bus and get on.Function and the CAN Bus Interface Unit of K line interface unit are similar.Power supply monitoring and administrative unit are responsible for the power supply of Real Time Monitoring motherboard circuit, show by the LED bi-colour LED, if find that supply voltage is too low, notify the ARM7 core processor that important information is preserved resetting processor chip simultaneously.The useful data that usb interface unit is responsible for that the ARM7 core processor had been processed turns usb interface unit by serial ports and converts usb signal to, communicates by standard USB line and diagnosis computer.The firmware downloads interface is joint test working group jtag interface, is used for the program updates of ARM7 core processor.

Compared with prior art, the beneficial effects of the utility model are:

1, the utility model adopts the mentality of designing of K line interface and CAN communication integral and the method for the unitized transmission of information to make it can support multiple diagnosing protocol, and the diagnosing protocol that can support comprises: ISO15031, ISO14230, ISO15765, SAEJ1939.Engine ECU, the DCU type supported comprise Denso, Bosch, triumphant dragon etc., effectively solve the shortcoming that current general diagnostic equipment is only supported single diagnosing protocol type, single engine type.

2, the utility model leaves JTAG firmware downloads mouth, can upgrade firmware, and the diagnosing protocol that other vehicles of scalable expansion adopt on existing diagnosing protocol basis effectively solves current general diagnostic equipment and do not have the shortcoming that the diagnosing protocol function is expanded in upgrading.

3, the utility model adopts the usb communication interface, completes K line signal, CAN bus signals to the conversion of usb communication form.Effectively solve current general diagnostic device Diagnostic interface single, the shortcoming of poor compatibility.

Description of drawings

Fig. 1 is the utility model structural representation.

Fig. 2 is the utility model CAN Bus Interface Unit data transmit-receive circuit block diagram.

Fig. 3 is the utility model K line interface cell data transmission circuit block diagram.

Fig. 4 is the utility model data diagnosis interface OBD pinouts.

Fig. 5 is the circuit diagram of the utility model power management and monitoring means circuit.

Fig. 6 is the circuit diagram that the utility model serial ports turns the USB circuit.

Embodiment

Below in conjunction with accompanying drawing, the utility model is described further.

Be illustrated in figure 1 as the structural representation of the utility model vehicle-borne diagnosis instrument, comprise conventional data diagnose interface OBD, USB interface and motherboard circuit, data diagnosis interface OBD is connected with ECU (Electrical Control Unit) ECU and the SCR aftertreatment urea solution jet control module DCU of automobile, and USB interface is connected with diagnosis computer; Motherboard circuit comprises that CAN Bus Interface Unit, K line interface unit, ARM7 core processor and serial ports turn usb interface unit, data diagnosis interface OBD is connected to the ARM7 core processor by CAN Bus Interface Unit and K line interface unit respectively, and the ARM7 core processor turns usb interface unit by serial ports and connects USB interface.Motherboard circuit also is provided with power supply monitoring and administrative unit and firmware downloads interface, and power management is connected respectively the ARM7 core processor with monitoring means, firmware downloads interface.The OBD interface can directly be inserted on the diagnostics port of the ECU of automobile or DCU, and this failure diagnostic apparatus is supported hot plug.USB interface can connect with diagnosis computer, thereby sets up a diagnosis computer to the full duplex channel of the data communication of automobile ECU and DCU.

ARM7 core processor of the present utility model can adopt the LPC2109 chip, and serial ports turns usb interface unit can adopt the FT232RL chip.

Be illustrated in figure 2 as the CAN bus data transmission circuit block diagram of CAN Bus Interface Unit, CAN bus interface 1 is articulated on the CAN bus of automotive system, and the CAN bus data is transmitted by a pair of differential signal line.CAN bus transceiver 2 can guarantee the reliability of data transmission under relatively abominable working environment, it is interface unique between node device and CAN bus, the end that CAN bus transceiver 2 is communicated by letter with the ARM7 core processor has input RXD and two ports of output TXD, the data receiver that ECU and DCU can be mail on the CAN bus gets off, and be connected to through buffer circuit 3 by output TXD mouth on the input port of inside CAN controller 5 of ARM7 core processor, also the data through buffer circuit 4 that the inside CAN controller 5 of ARM7 core processor is exported can be suspended on the CAN bus simultaneously, receive for ECU and DCU.

Be illustrated in figure 3 as the K line data transmit-receive circuit block diagram of K line interface unit, the data that send up from ECU input to the I/O mouth of ARM7 core processor 8 through over-voltage comparator 7 by K bus interface 6, from the data of ARM7 core processor 8 output through over-voltage comparator 9, hang 6 by the K bus interface again and receive on the K bus, receive for ECU.

In the utility model real work, at first the ARM7 core processor monitors the voltage on the K bus, if monitor on the K bus and have voltage, think that the equipment that OBDII connects is the K bus apparatus, OBDII uses integrated K bus protocol to set up communicating by letter between the ECU/DCU of diagnosis computer and automobile; Otherwise, remain zero in a period of time if monitor on the K bus voltage, think that the equipment that OBDII connects is the CAN bus apparatus, OBDII uses integrated CAN bus protocol to set up communicating by letter between the ECU/DCU of diagnosis computer and automobile.

Be illustrated in figure 4 as the utility model OBD interface pin figure, as can be seen from the figure CAN bus and K line are received on the OBD interface simultaneously.The pin of OBD interface is respectively CANH and the CANL signal wire in the CAN bus, and the signal wire of K bus.

Be illustrated in figure 5 as power management and monitoring means, supply voltage is normal under normal circumstances, in diagnostic equipment, whole system is also to be operated in normal data transmit-receive state, in case supply voltage bust, can inform the ARM7 core processor by electric source monitoring circuit, processor can be kept at EEPROM with important information within the extremely short time in, whole system simultaneously resets.

Be illustrated in figure 6 as the utility model serial ports and turn the USB circuit, major function is for to be transformed to usb data with serial data by conversion chip, in order to be connected with computing machine.

Claims

1. the failure diagnostic apparatus of an automotive Diesel engine, it is characterized in that comprising conventional data diagnose interface OBD, USB interface and motherboard circuit, data diagnosis interface OBD is connected with ECU (Electrical Control Unit) ECU and the SCR aftertreatment urea solution jet control module DCU of automobile, and USB interface is connected with diagnosis computer; Motherboard circuit comprises that CAN Bus Interface Unit, K line interface unit, ARM7 core processor and serial ports turn usb interface unit, data diagnosis interface OBD is connected to the ARM7 core processor by CAN Bus Interface Unit and K line interface unit respectively, and the ARM7 core processor turns usb interface unit by serial ports and connects USB interface.

2. the failure diagnostic apparatus of a kind of automotive Diesel engine according to claim 1, it is characterized in that motherboard circuit also is provided with power supply monitoring and administrative unit and firmware downloads interface, power management is connected respectively the ARM7 core processor with monitoring means, firmware downloads interface.