CN101430557B - Multi-protocol data transducer used for vehicle fault diagnosis and its diagnosis processing method - Google Patents

Abstract

The invention discloses a multi-protocol data converter for automobile fault diagnosis, which comprises a vehicle connection interface and an RS232 interface connected with a micro-controller, and a converter power supply circuit is respectively arranged between the micro-controller and the vehicle connection interface and K line signal conditioning circuit, CAN signal conditioning circuit and ALDL signal conditioning circuit, RS232 signal conditioning circuit is arranged between the microcontroller and the RS232 interface, and the vehicle connection interface adopts the standard in compliance with ISO 15031-3 and SAEJ1962 EOBD and OBDII connectors; the microcontroller is embedded with a vehicle protocol automatic search module and a protocol diagnostic module; the protocol diagnostic module includes a diagnostic processing submodule of the ISO15765/SAE J1939 protocol and SAE J1850/ISO 9141/ISO 14230/ The diagnostic processing sub-module of the KW1281/ALDL protocol; the SAEJ1850 signal conditioning circuit for realizing J1850 VPW and J1850 PWM signal conditioning is also arranged between the microcontroller and the vehicle connection interface; the microcontroller and the above-mentioned The connection between the signal conditioning circuits is realized through the microcontroller interface circuit. At the same time, the invention also discloses a diagnosis method of the data converter.

Description

Multi-protocol data converter and diagnostic processing method for automobile fault diagnosis

technical field

The patent of the present invention relates to a data converter for automobile fault diagnosis, in particular to a multi-protocol data converter for automobile fault diagnosis in the development of PC-based vehicle fault diagnosis system and handheld vehicle fault diagnosis equipment.

Background technique

Since the 1950s, through the combination of automotive technology and electronic technology, the application of electronic technology in automobiles has become wider and wider, and it has provided automotive electronic control systems with fast speed, powerful functions, reliable performance, and low cost. It greatly improves the power, economy, safety and comfort of the car. However, due to the unprecedented complexity of the vehicle system due to the electronic control of the vehicle, it has brought more and more difficulties to the vehicle maintenance work. In response to this situation, by the end of the 1970s and the beginning of the 1980s, most automobile manufacturers in the world began to use electronic means to detect and diagnose the functions and faults of various components of automobile engines and other electronic control systems, and monitor the various systems of automobiles in real time. Working status, while providing maintenance personnel with a basis for diagnosis and troubleshooting. This is OBD (On-Board Diagnostics)-on-board diagnostic system.

On the other hand, since automobiles have become one of the largest sources of air pollution around the world, many countries currently regard the control of vehicle emissions as an important task to improve the quality of the atmospheric environment, which directly leads to the rapid development of OBD systems related to automobile emissions. The emission-related OBD system uses on-board diagnostic technology to monitor and diagnose vehicle emission-related systems. The emission-related OBD system is not based on the direct measurement of the required monitoring values, but needs to establish the corresponding relationship between the monitored signal and the required emission measurement results through an indirect algorithm that is fully credible. When the signal changes abnormally, the The potential trends that may affect the emission level can be accurately judged and alarmed, so as to achieve the purpose of reducing emissions. Practical experience has proved that OBD technology is one of the most effective technical means to control vehicle emissions. Countries around the world have formulated regulations to promote the application of this technology. ) Three types of OBD technology systems.

The United States was the first country to promote the advancement of OBD technology. In 1982, CARB (California Air Resources Board) established that all vehicles sold in California must be equipped with on-board diagnostic system OBD since 1988 to control the failure of the emission system. . Due to the defects of the early on-board diagnostic system (now called OBD I), in 1988 CARB started the standard research of the second generation OBD system, called OBD II system. After 1994, SAE continued to revise the relevant content of OBD II, promulgating a series of standards such as SAE J1962, SAE J2012, SAE J1930, SAE J1978, SAE J1979 and SAE J1850. It has been certified by the Environmental Protection Agency (EPA) and the California Resources Association (CARB) and requires each automobile manufacturer to provide a unified diagnostic interface, communication method and fault code in accordance with the OBD-II standard. Therefore, after 2004, the revised OBD II system became the advanced OBD II system (Revised OBD II).

When the United States implemented OBD-II, the European Community also required the cars produced by European automakers to be equipped with European electronically controlled vehicle microcomputer fault diagnosis systems, that is, EOBD (European On-board Diagnosis System), and gradually promulgated ISO 9141, ISO 14230, ISO 14229, ISO 15031, ISO 15765 and other related standards. According to EU-Richtlinle 1999/102/EG regulations, in 2001 all newly produced cars in Europe (with a load less than 2.5 tons) were limited to gasoline engines equipped with EOBD systems, while diesel engine cars were required to be equipped with EOBD systems in 2004. 98/69/EC stipulates the technical and test requirements for Euro III and Euro IV light vehicles to install on-board diagnostic (OBD) system.

In Japan, how to respond to the strengthening trend of automobile emission regulations has always been an important issue for automobile manufacturers. On September 20, 2003, the Japanese Ministry of Land, Infrastructure, Transport and Tourism revised the emission standards for passenger cars, trucks and buses, and formulated what is known as the most stringent "new long-term emission regulations" in the world. This regulation stipulates that new models will start from October 1, 2005, and new emission regulations will be implemented on September 1, 2007 for models that have been put into production and continue to be produced. The matching "on-board fault diagnosis system" - OBD will play a greater role in monitoring than ever before. At the same time, the importance of "Scan Too1" connected to the OBD system from the outside of the car is also more noticeable. It seems that in Japan "the era of highly electronic maintenance" is coming. In order to comply with the enhanced emission regulations in September 1998, the installation of OBD is mandatory, and it is stipulated that it will be implemented from new passenger cars from October 2000, and then expanded to in-use vehicles. In order to adapt to the new emission regulations, the Japanese automobile industry plans to develop a new generation of self-diagnosis systems for detecting and monitoring emission reduction devices. That is, more accurate OBDs are required to efficiently diagnose the concentration of exhaust gas based on information from various sensors and to ensure early detection of malfunctions.

The work in the field of OBD in my country is still in its infancy. According to the relevant requirements of the "Environmental Protection Law of the People's Republic of China" and the "Law of the People's Republic of China on Air Pollution Prevention and Control", the State Environmental Protection Administration and the State Administration of Quality Supervision, Inspection and Quarantine announced in April 2005 On the 15th, GB18352.3-2005 "Light Vehicle Pollutant Emission Limits and Measurement Methods (China Phase III and IV)" was jointly promulgated. On December 31, 2005, Beijing began to implement the national phase III emission regulations ahead of schedule, and required new models to have an OBD system. From January 1, 2007, vehicles sold in Guangzhou must have an OBD system. On July 1, 2007, Phase III of the standard GB18352.3-2005 "Light Vehicle Pollutant Emission Limits and Measurement Methods (China Phase III, IV)" began to be implemented. From July 1, 2008, the first category of gasoline vehicles (M1 vehicles with no more than six seats and a maximum total mass of no more than 2500kg) are required to be equipped with an OBD system. Compliance checks are performed synchronously. From July 1, 2010, all light vehicles are required to be equipped with OBD systems.

All in all, under the impetus of the development of automotive electronics technology and the automobile-related laws and regulations of various countries, at present, automobiles produced at home and abroad are widely equipped with OBD systems. This system is one of the most important means of modern vehicle fault diagnosis. It includes a self-diagnosis program that is added to each electronic control unit (ECUs) of the vehicle for online monitoring and diagnosis of vehicle system faults and component faults. It has The function of identifying areas that may be faulty and storing this information in the memory of the ECU in the form of a fault code. At the same time, for the convenience of diagnosis and maintenance, a special diagnosis interface is also set up. Using external diagnostic equipment, through this diagnostic interface, you can read the fault information recorded by the vehicle or test the working status of related systems and components.

The OBD system has been gradually standardized under the promotion of automobile-related laws and regulations in various countries, but due to historical reasons, it will still not be completely unified for a long time in the future. These unified contents are especially reflected in the communication methods used. At present, the data exchange protocols used by the automotive OBD system in communication with external diagnostic equipment include SAE J1850, ISO 9141, ISO 14230, and ISO 15765 recommended by OBD specifications in various countries, as well as some independent protocols used by vehicle manufacturers, such as K1281 and ALDL, etc. . Due to the large number of automobile brands currently produced and sold in our country, the communication protocols used by the equipped OBD systems are also various, and they are not compatible with each other. Therefore, generally speaking, the fault diagnosis instrument is developed for a single car model, and it is an expensive equipment that can only be equipped by a professional vehicle repair shop or 4S shop.

The publication date is January 9, 2008. The Chinese invention patent with the announcement number CN201004013 discloses a diagnostic system for automotive electronic control units; the technical solution of the system includes a USB diagnostic protocol conversion box and a USB diagnostic protocol conversion box. computer and a diagnostic cable connecting the USB diagnostic protocol conversion box and the vehicle diagnostic seat; the USB diagnostic protocol conversion box includes a CAN bus interface unit and a K bus interface unit; the diagnostic cable is connected to the CAN bus interface unit or the K bus interface unit The car diagnostic socket is connected; the computer includes a diagnostic database and a diagnostic unit. The USB diagnostic protocol conversion box in the above technical solution can only be connected to the CAN bus or the K bus, and cannot better adapt to the diversity of vehicle diagnostic communication forms; when the communication data exchange between the vehicle and the diagnostic equipment, its USB diagnostic The protocol conversion box can only realize the conversion between CAN bus or K bus data flow and USB bus data flow, therefore, the corresponding diagnostic equipment must have the protocol processing function of the network layer and data link layer of CAN bus or K bus, so that Increased complexity of diagnostic equipment.

Contents of the invention

Due to the large number of automobile brands currently produced and sold in our country, the communication protocols used by the equipped OBD systems are also various, and they are not compatible with each other. Therefore, generally speaking, the fault diagnosis instrument is developed for a single car model, and it is an expensive equipment that can only be equipped by a professional vehicle repair shop or 4S shop. The present invention provides a multi-protocol data converter for automobile fault diagnosis, which can be applied to various vehicle fault diagnosis systems, and is a data conversion device compatible with various communication protocols currently used in automobiles. The multi-protocol data converter for vehicle fault diagnosis is applied in the development of PC-based vehicle fault diagnosis system and handheld vehicle fault diagnosis equipment, so that the developers of vehicle diagnostic instruments can focus on the software development of the application layer, which can greatly shorten the development time. Reduce development costs.

In order to solve the above-mentioned technical problems, the technical scheme realized by the multi-protocol data converter for automobile fault diagnosis of the present invention is: comprising a vehicle connection interface and an RS232 interface connected with a microcontroller, the connection between the microcontroller and the vehicle connection interface A converter power supply circuit, a K-line signal conditioning circuit, a CAN signal conditioning circuit, and an ALDL signal conditioning circuit are arranged between the microcontroller and an RS232 signal conditioning circuit, and the vehicle connection interface adopts ISO Standard EOBD and OBDII universal connectors specified by 15031-3 and SAE J1962; the microcontroller is embedded with a vehicle protocol automatic search module and a protocol diagnostic module; the protocol diagnostic module includes a diagnostic processing submodule of the ISO15765/SAE J1939 protocol and the SAE J1850/ISO 9141/ISO 14230/KW1281/ALDL protocol diagnostic processing sub-module; the microcontroller and the vehicle connection interface are also provided with a SAE J1850 signal conditioning circuit for realizing J1850VPW and J1850PWM signal conditioning. The K line signal conditioning circuit is used to realize the signal conditioning of the three protocols of ISO 9141, ISO 14230 and KW1281; the CAN signal conditioning circuit is composed of ISO15765 and SAE J1939 signal conditioning circuits, and is used to realize the ISO15765 standard ID and expansion The standard ID of the ID, the ISO 14229 protocol and the CAN communication mode of the extended ID, and the signal conditioning of the SAE J1939 mode; the connection between the microcontroller and the above-mentioned signal conditioning circuits is realized by a microcontroller interface circuit.

Using the above-mentioned multi-protocol data converter for vehicle fault diagnosis to carry out automatic vehicle protocol search and diagnosis processing method includes the following steps:

(1) Start the vehicle protocol automatic search module in the micro-controller while powering on, thereby search for the communication protocol used by the vehicle, and record the vehicle protocol number DP_N, and the protocol relationship corresponding to the DP_N value is as follows:

DP_N=0, the protocol used by the vehicle is a communication protocol not supported by the converter;

DP_N=1, the protocol used by the vehicle is the SAE J1850 communication protocol supported by the converter;

DP_N=2, the protocol used by the vehicle is the ISO9141 communication protocol supported by the converter;

DP_N=3, the protocol used by the vehicle is the ISO14230 communication protocol supported by the converter;

DP_N=4, the protocol used by the vehicle is the ISO15765 communication protocol supported by the converter;

DP_N=5, the protocol used by the vehicle is the SAE J1939 communication protocol supported by the converter;

DP_N=6, the protocol used by the vehicle is the ALDL communication protocol supported by the converter;

DP_N=7, the protocol used by the vehicle is the KW1281 communication protocol supported by the converter;

(2) If the recorded vehicle protocol number DP_N=0, then flash the two light-emitting diodes VD2 and VD3 connected to the microcontroller at the same time to warn the operator;

(3) If the recorded vehicle protocol number DP_N is not 0, enter the state where the RS232 signal processing circuit is waiting to receive diagnostic instructions; when the RS232 signal processing circuit receives instructions or data, first judge whether the instructions or data conform to the requirements of the vehicle connection interface ISO14229, ISO15031-5 or SAEJ1979 specifications; if it does not meet one of the above ISO14229, ISO15031-5 or SAEJ1979 specifications, it will feed back the message "the request command is not standardized", otherwise call the corresponding protocol diagnostic module for diagnostic processing according to the DP_N value, One of the following two situations;

(3-1) If DP_N=1, DP_N=2, DP_N=3, DP_N=6 or DP_N=7, the diagnostic handler of the SAE J1850/ISO 9141/ISO 14230/KW1281/ALDL protocol embedded in the controller The module performs the following diagnostic processing in accordance with the OSI open interconnection mode: First, it receives instructions in the UP_D format of the application layer data conforming to the ISO14229, ISO 15031-5 or SAE J1979 specifications; then, converts the received UP_D format instructions into corresponding diagnostic protocol chains The data in LP_D format of the road layer data is sent to the vehicle OBD system; after sending the command, it waits to receive the response data from the vehicle ECU; after receiving a response data in LP_D format, it is directly converted into UP_D format, and the response data is sent through RS232; When the waiting time overflows, exit the above diagnostic process;

(3-2) If DP_N=4 or DP_N=5, the diagnostic processing sub-module of the ISO 15765/SAE J1939 protocol embedded in the controller performs the following diagnostic processing in accordance with the OSI open interconnection mode: first, the reception conforms to ISO14229, ISO15031- 5 or SAE J1979 standard application layer data UP_D format instructions; then, convert the received UP_D format instructions into data that conforms to the corresponding diagnostic protocol link layer data LP_D format and send them to the vehicle OBD system; after sending the instructions, wait for receiving The data responded by the vehicle ECU; if it is a single-frame response data, directly convert the response LP_D format data into UP_D format, and send the response data through RS232; if it is a multi-frame response data, first convert its multi-frame response data After sorting and storing according to the ID, wait until the entire message is received, then directly convert the response LP_D format data into UP_D format, and send the response data through RS232; when the waiting time overflows, exit the above diagnostic process.

Compared with prior art, the beneficial effect of the present invention is:

(1) The multi-protocol data converter used for automobile fault diagnosis of the present invention fully supports the automobile diagnosis communication protocol required by National III, EOBD and OBDII, including SAE J1850, ISO9141, ISO14230 and ISO15765. On this basis, non-legal requirements are also added But widely used SAE J1939, ALDL and KW1281. That is to say, the data converter supports a total of seven on-board diagnostic communication protocols, and this is the diagnostic communication protocol used by most of the cars currently sold in our country.

(2) The multi-protocol data converter for automobile fault diagnosis of the present invention can automatically search for the diagnostic communication protocol supported by the vehicle OBD system when powered on, and then perform data exchange with the upper diagnostic equipment according to the searched communication protocol.

(3) The multi-protocol data converter that the present invention is used for automobile fault diagnosis has completed the processing of the data link layer and the network layer of the seven kinds of protocols supported when completing the communication data exchange between the vehicle and the diagnostic equipment. The data exchanged with the upper diagnostic equipment through RS232 fully complies with the diagnostic services and data formats specified in ISO 14229, ISO 15031-5 and SAE J1979. Therefore, the diagnostic software can be simplified when the diagnostic equipment is developed by using the present invention, only need to focus on the development of the diagnostic application layer, shorten the development cycle, and reduce the development cost.

(4) As shown in Figure 1, one end of the multi-protocol data converter used for automobile fault diagnosis of the present invention is connected with the vehicle diagnosis interface, and the other end is to exchange data in the form of RS232 serial port. The communication connection between the data converter and the vehicle is compatible with all communication connection methods stipulated in my country's GB 18352.3-2005 "Limits and Measurement Methods of Pollutant Emissions from Light Vehicles" (China Phase III, IV), and expands on this method Double K line and ALDL connection. The data format exchanged by the RS232 interface complies with the data format and diagnostic services specified in ISO 15031-5, SAE J1979 and ISO 14229. The invention is mainly applied in the development of PC-based vehicle fault diagnosis system and hand-held vehicle fault diagnosis equipment, which can greatly shorten the development time and reduce the development cost.

Description of drawings

Fig. 1 is a schematic diagram of the connection relationship between the multi-protocol data converter and the peripheral devices used for automobile fault diagnosis in the present invention;

Fig. 2 is the multi-protocol data converter hardware structural block diagram that the number of the present invention is used for automobile fault diagnosis;

Fig. 3 is a schematic diagram of the definition of vehicle connection interface pins shown in Fig. 2;

Fig. 4 is the SAE J1850 signal conditioning circuit diagram shown in Fig. 2;

Fig. 5 is the signal conditioning circuit diagram of ISO 9141, ISO 14230 and KW1281 shown in Fig. 2;

Fig. 6 is the signal conditioning circuit diagram of ISO15765 and SAE J1939 shown in Fig. 2;

Fig. 7 is a circuit diagram of RS232 and ALDL signal conditioning shown in Fig. 2;

Fig. 8 is the RS232 interface circuit diagram shown in Fig. 2;

Fig. 9 is an interface circuit diagram of the microcontroller shown in Fig. 2;

Fig. 10 is the overall structural block diagram of the multi-protocol data converter embedded module that is used for automobile fault diagnosis;

Fig. 11 is a program flow chart of using the data converter of the present invention to automatically search for vehicle protocols;

Fig. 12 is a flowchart of SAE J1850/ISO 9141/ISO 14230/KW1281/ALDL protocol diagnostic processing performed by the data converter of the present invention;

Fig. 13 is a flow chart of the ISO 15765/SAE J1939 protocol diagnosis process performed by the data converter of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Connection relationship between the data converter and peripherals of the present invention

As shown in Figure 1, the data converter is composed of a vehicle connection interface, a data conversion circuit and an RS232 interface. The data converter is connected to the vehicle OBD diagnostic interface through the vehicle connection interface, and exchanges data with the upper diagnostic equipment through RS232. The data conversion circuit mainly completes the conversion of the data format between the two interfaces.

The multi-protocol data converter used for automobile fault diagnosis of the present invention can complete the following functions:

(1) The converter is powered by the vehicle battery through the vehicle connection interface. It is compatible with 12V and 24V vehicle battery systems, and can withstand a power supply range of 9 to 36V in normal operation.

(2) When the data converter is connected to the vehicle, it supports five on-board diagnostic communication protocols: SAE J1850, ISO9141, ISO14230, ISO15765, SAEJ1939, ALDL and KW1281.

(3) The data converter supports the diagnostic services and data formats specified in ISO 14229, ISO15031-5 and SAE J1979 when exchanging data with the upper diagnostic equipment through RS232.

(4) When the data converter is powered on, it can automatically search for the diagnostic communication protocol supported by the vehicle OBD system, and then exchange data with the upper diagnostic equipment according to the searched communication protocol.

The present invention is used for the hardware system of the multi-protocol data converter of automobile fault diagnosis

The hardware structure of the data converter is shown in Figure 2, including the vehicle connection interface and the RS232 interface connected with the microcontroller, and a converter power supply circuit is respectively arranged between the microcontroller and the vehicle connection interface to realize J1850VPW and SAE J1850 signal conditioning circuit for signal conditioning in J1850PWM two modes; K-line signal conditioning circuit for signal conditioning of three protocols of ISO 9141, ISO 14230 and KW1281; composed of ISO15765 and SAE J1939 signal conditioning circuit for realizing CAN communication mode conforming to ISO15765 standard ID and extended ID, ISO 14229 protocol standard ID and extended ID, and CAN signal conditioning circuit for SAE J1939 signal conditioning; ALDL signal conditioning circuit; between the microcontroller and the RS232 interface An RS232 signal conditioning circuit is provided, and the vehicle connection interface adopts standard EOBD and OBDII connectors conforming to the provisions of ISO 15031-3 and SAE J1962; the microcontroller is embedded with a vehicle protocol automatic search module and a protocol diagnosis module; the said The protocol diagnostic module includes a diagnostic processing submodule of the ISO15765/SAEJ1939 protocol and a diagnostic processing submodule of the SAE J1850/ISO 9141/ISO 14230/KW1281/ALDL protocol; the connection between the microcontroller and the above-mentioned signal conditioning circuits is through The interface circuit of the microcontroller is realized.

Among them, the pin definition of the vehicle connection interface is shown in Figure 3: the 2-pin lead is connected to SAE J1850+, the 4 and 5-pin leads are grounded, the 6-pin lead is connected to CAN_H, the 7-pin lead is connected to K/K1, and the 9-pin lead is connected to SAE 1850- , The 14-pin lead is connected to CAN_L, the 15-pin lead is connected to L/K2, and the 16-pin lead is connected to VB.

The vehicle power supply circuit is mainly connected to the vehicle to input the battery voltage (12V or 24V) and output 5V and 8V power supply through the power module to supply the various parts of the circuit of the converter.

The SAE J1850 signal conditioning circuit includes J1850 VPW and J1850 PWM signal conditioning. The circuit is shown in Figure 4. The TXPWM+ lead is connected to the base of the transistor Q3 through a resistor. The collector of the transistor Q3 is divided into two circuits, one of which is Connect to the vehicle power supply VB, the other is connected to the SAE J1850- lead through a resistor, the drain of the transistor Q3 is connected to the SAE J1850+ lead through a diode; the RXPWM lead is connected to the output terminal of the operational amplifier N4, and the power supply terminal of the operational amplifier N4 is connected to To the vehicle power supply VB, the ground terminal is grounded; the positive input terminal of the operational amplifier N4 is connected to the SAE J1850+ lead through a resistor, and the negative input terminal of the operational amplifier N4 is connected to the SAEJ1850-lead through a resistor; the TXPWM-lead is connected to the triode through a resistor The base of Q4, the collector of the transistor Q4 is connected to the SAE J1850- lead, the drain of the transistor Q4 is divided into two circuits, one of which is connected to the SAE J1850+ lead through a resistor, and the other is connected to the ground; the TXVPWM lead is connected to the operational amplifier N4 The positive input terminal of the operational amplifier N4 is divided into three circuits, one of which is connected to the 5-volt power supply Vcc through a resistor, the other is connected to the ground through a resistor, and the other is connected to the negative input terminal of the operational amplifier N4. The output terminal of the amplifier N4 is divided into two circuits, one of which is connected to the 8-volt power supply +8 through a resistor, and the other is connected to the base of the transistor Q5 through a resistor; the collector of the transistor Q5 is connected to the 8-volt power supply +8, and the drain The pole is connected to the SAE J1850+ lead through a diode; the RXPWM lead is connected to the output of op amp N4, and the positive input of op amp N4 is connected to the SAE J1850+ lead.

The K-line signal adjustment circuit includes signal conditioning of three protocols of ISO 9141, ISO 14230 and KW1281. The circuit is shown in Figure 5. The TXK lead is connected to the base of the transistor Q1 through a resistor, and the collector of the transistor Q1 is divided into two circuits. One of them is connected to the vehicle power supply VB through a resistor, the other is connected to the base of the transistor Q6, the drain of the transistor Q1 is connected to the ground; the drain of the transistor Q6 is connected to the ground, and the collector of the transistor Q6 is divided into three circuits, one of which is connected to a The resistor is connected to the vehicle power supply VB, the other is connected to the positive input terminal of the operational amplifier N3 through a resistor, and the other is connected to the K/K1 lead; the RXK lead is connected to the output terminal of the operational amplifier N3, and the power terminal of the operational amplifier N3 is connected to To the vehicle power supply VB, the ground terminal is grounded; the negative input terminal of the operational amplifier N3 is divided into three circuits, one of which is connected to the vehicle power supply VB through a resistor, the other is connected to the ground through a resistor, and the other is connected to the operational amplifier N3 The negative input terminal; the RXL lead is connected to the output terminal of the operational amplifier N3 through a resistor; the positive input terminal of the operational amplifier N3 is divided into three routes through a resistor, one of which is connected to the vehicle power supply VB through a resistor, and the other is connected to L/ The K2 lead is connected to the collector of the transistor Q7; the TXL lead is connected to the base of the transistor Q2 through a resistor, and the collector of the transistor Q2 is divided into two circuits, one of which is connected to the vehicle power supply VB through a resistor, The other path is connected to the base of the transistor Q7, the drain of the transistor Q2 is connected to the ground, and the drain of the transistor Q7 is connected to the ground.

As shown in Figure 6, the CAN signal conditioning circuit is: the output terminal of the CAN transceiver D3 is connected to the CANTX lead, the ground terminal is grounded, and the power supply terminal is divided into two circuits, one of which is connected to the 5 volt power supply Vcc, and the other through a capacitor Connect to the ground, the data receiving input terminal is connected to the CANRX lead, the low-level CAN bus terminal is divided into two routes, one of which is connected to the CANL lead, and the other is connected to the ground through a resistor and a capacitor in turn, and the high-level CAN bus terminal Divided into two circuits, one of which is connected to the CANH lead, the other is connected to the ground through a resistor and a capacitor in sequence, and the high-speed/quiet mode selection terminal is connected to the ground through a resistor.

As shown in Figure 7, the ALDL and RS232 signal adjustment circuit is: the RS232 transceiver charge pump 1 positive terminal is connected to the RS232 transceiver charge pump 1 negative terminal through a capacitor, and the RS232 transceiver power supply terminal is connected to 5 volts through a capacitor Power supply Vcc, the positive terminal of RS232 transceiver charge pump 2 is connected to the negative terminal of RS232 transceiver charge pump 2 through a capacitor, the ground terminal of RS232 transceiver is connected to ground through a capacitor, and the first channel R232 bus output terminal of RS232 transceiver is connected to RS232TX Lead wire, RS232 transceiver first channel R232 bus input terminal connected to RS232RX lead wire, RS232 transceiver first channel data receiving output end connected to TX lead wire, RS232 transceiver first channel data sending output end connected to RX lead wire, RS232 transceiver The data sending output of the second channel is connected to the ALDLOUT lead, the data receiving output of the second channel of the RS232 transceiver is connected to the ALDLIN lead, the R232 bus input of the second channel of the RS232 transceiver is connected to the ALDL lead through a resistor, and the second channel of the RS232 transceiver is connected to the ALDL lead. The output terminal of the channel R232 bus is connected to the ALDL lead through a diode, and the ground terminal of the RS232 transceiver is divided into two circuits, one of which is connected to the ground, and the other is connected to the 5-volt power supply Vcc through a capacitor, and the power supply terminal of the RS232 transceiver is connected to the 5-volt power supply Vcc.

As shown in Figure 8, the circuit of the RS232 interface is: the circuit of the RS232 interface is: the second pin of the RS232 interface is connected to the RS232RX lead, the third pin is connected to the RS232TX lead, and the fifth pin is grounded.

As shown in Figure 9, the interface circuit of the micro-controller of the data converter of the present invention is: the interface circuit of the micro-controller is: the reference voltage end of the micro-controller is divided into two paths, wherein, one path is connected to 5 volt power supply Vcc, the other is connected to the ground through a resistor RA1 output/input is connected to TXPWM+ lead, RA2 output/input is connected to TXVPWM lead, RA3 output/input is connected to RXL lead, clock oscillation circuit input/output 1 The terminal is divided into two circuits, one of which is connected to the ground through a capacitor, and the other is connected to the crystal through another capacitor. Then connect to the crystal through another capacitor, RC0 output/input terminal is connected to RXVPWM lead, RC1 output/input terminal is connected to RXK lead, RC2 output/input terminal is connected to RXPWM lead, RC3 output/input terminal is connected to TXVPWM-lead, The RC4 output/input terminal is connected to the ground, the RC4 output/input terminal is connected to the ground, the data transmission output terminal is connected to the TX lead, the data receiving input terminal is connected to the RX lead wire, the ground terminal is connected to the ground, and the power supply terminal is divided into two paths, one of which Connect to the 5 volt power supply Vcc, the other way is connected to the ground through a capacitor, the RB0 output/input terminal is connected to the TXL lead, the RB1 output/input terminal is connected to the TXK lead, the CAN bus data sending output is connected to the CANRX lead, and the CAN bus data The receiving input is connected to the CANTX lead, the RB4 output/input is connected to the ALDLOUT lead, the RB5 output/input is connected to the ALDLIN lead, the RB6 output/input is connected to the 5-volt power supply Vcc through a resistor and a light-emitting diode in turn, and RB7 The output/input terminal is connected to the 5-volt power supply Vcc through a resistor and a light-emitting diode in sequence.

Using the multi-protocol data converter for automobile fault diagnosis of the present invention to realize the process of automatic vehicle protocol search and fault diagnosis processing

As shown in Figure 10 and Figure 11, when powered on, the data converter first starts the vehicle protocol automatic search program to search for the communication protocol used by the vehicle, and records the vehicle protocol number DP_N. The recorded DP_N values are shown in Table 1. If the communication protocol used by the vehicle is not supported by the converter, that is, DP_N=0, then flash OBDLED and RS232LED at the same time to warn the operator: the converter does not support the communication protocol used by the vehicle. If DP_N is not zero, enter the state where RS232 is waiting to receive diagnostic commands. When RS232 receives a command (or data), first judge whether the command (or data) complies with ISO14229, ISO 15031-5 or SAE J1979 specifications.

Table 1 The protocol corresponding to the value of the vehicle protocol number DP_N

DP_N Corresponding agreement 0 The converter does not support the communication protocol used by the vehicle 1 The converter supports SAE J1850 protocol 2 The converter supports the ISO9141 protocol 3 The converter supports the ISO14230 protocol 4 The converter supports the ISO15765 protocol 5 The converter supports SAE J1939 protocol 6 The converter supports the ALDL protocol 7 The converter supports KW1281 protocol

If it does not conform to one of the above ISO14229, ISO15031-5 or SAEJ1979 specifications, it will feed back the message "the request command is not standardized", otherwise it will call the corresponding protocol diagnostic module for diagnostic processing according to the value of DP_N, and there will be one of the following two situations;

(1) If DP_N=1, DP_N=2, DP_N=3, DP_N=6 or DP_N=7, the diagnostic processing sub-module of the SAEJ1850/ISO9141/ISO14230/KW1281/ALDL protocol embedded in the controller performs the following diagnostic processing :

According to the OSI open interconnection mode, the SAE J1850/ISO 9141/ISO 14230/KW1281/ALDL protocol is characterized by only the physical layer and the data link layer, and its corresponding application layer conforms to the ISO14229, ISO 15031-5, and SAE J1979 specifications. At the same time, these five communication protocols all support multi-ECU responses to requests, and none of them support multi-frame responses from the same ECU. Therefore, although their data formats are different, the way of data flow is consistent. Therefore, their diagnostic processing flow is explained here together. The diagnostic processing flow of SAE J1850/ISO 9141/ISO 14230/KW1281/ALDL protocol is shown in Figure 12 . Among them, the instruction in UP_D (application layer data) format is first received, that is, the instruction conforming to the ISO14229, ISO 15031-5 or SAE J1979 specification, and then the diagnostic processing program converts the received UP_D format instruction into LP_D (link road layer data format) format to the vehicle OBD system. After sending the instruction, it waits for receiving the response data from the vehicle ECU. Because there is no multi-frame response format of an ECU, the LP_D format data of each response can be directly converted into UP_D format, and the response data is sent through RS232. Exit the diagnostic handler when the wait time expires.

(2) If DP_N=4 or DP_N=5, the diagnostic processing sub-module of the ISO 15765/SAE J1939 protocol embedded in the controller performs the following diagnostic processing:

According to the OSI open interconnection model, the ISO 15765/SAE J1939 protocol includes the physical layer, the data link layer and the network layer. The application layer corresponding to ISO 15765 is the ISO14229, ISO 15031-5, and SAE J1979 specifications, and SAE J1939 itself has Contains the content of the application layer. These two kinds of communication protocols are specific implementation specifications of CAN communication. Among them, SAE J1939 only supports 29-bit ID extended frame, while ISO 15765 includes 11-bit standard frame and 29-bit ID extended frame. However, both communication protocols support multi-ECU responses to requests and multi-frame responses from the same ECU, so although their data flow methods are consistent, the diagnostic processing flow is shown in Figure 13. Among them, the instruction in UP_D (application layer data) format is first received, that is, the instruction conforming to the ISO14229, ISO 15031-5 or SAE J1979 specification, and then the diagnostic processing program converts the received UP_D format instruction into LP_D (link road layer data format) format to the vehicle OBD system. After sending the instruction, it waits for receiving the response data from the vehicle ECU. If it is the response data of a single frame, the LP_D format data of the response can be directly converted into the UP_D format, and the response data is sent through RS232. If it is multi-frame response data, first sort and store it according to the ID, and then convert the response LP_D format data into UP_D format directly after the entire message is received, and send the response data through RS232. Exit the diagnostic handler when the wait time expires.

Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, and the above-mentioned specific embodiments are only illustrative, rather than restrictive. Under the enlightenment of the present invention, many modifications can be made without departing from the gist of the present invention, and these all belong to the protection of the present invention.

Claims (7)

1. multi-protocol data transducer that is used for automobile failure diagnosis; Comprise vehicle connecting interface and the RS232 interface that is connected with microcontroller; Be respectively arranged with converter feed circuit and K line signal conditioning circuit, CAN signal conditioning circuit and ALDL signal conditioning circuit between said microcontroller and the vehicle connecting interface; Be provided with the RS232 signal conditioning circuit between said microcontroller and the RS232 interface, said vehicle connecting interface adopts and meets ISO 15031-3 and SAE J1962 specified standard EOBD and OBDII general connector; It is characterized in that:

Embed in the said microcontroller vehicle protocol automatic search module and protocol diagnosis module are arranged; Said protocol diagnosis module comprises the diagnostic process submodule of ISO15765/SAE J1939 agreement and the diagnostic process submodule of SAE J1850/ISO 9141/ISO 14230/KW1281/ALDL agreement;

Also be provided with the SAE J1850 signal conditioning circuit that is used to realize J1850VPW and J1850PWM dual mode signal condition between said microcontroller and the vehicle connecting interface;

Said K line signal conditioning circuit is used to realize the signal condition of ISO 9141, ISO 14230 and three kinds of agreements of KW1281;

Said CAN signal conditioning circuit is made up of ISO15765 and SAE J1939 signal conditioning circuit; Be used to realize meeting ISO15765 standard I D and Extended ID, the standard I D of ISO 14229 agreements and the CAN communication pattern of Extended ID, and the signal condition of SAE J1939 mode;

Connection between said microcontroller and above-mentioned each signal conditioning circuit realizes through the microcontroller interface circuit.

2. the multi-protocol data transducer that is used for automobile failure diagnosis according to claim 1 is characterized in that: the formation of said SAE J1850 signal conditioning circuit is:

The TXPWM+ lead-in wire is connected to the base stage of triode Q3 through a resistance; The collection utmost point of triode Q3 is divided into two-way; Wherein one the road be connected to vehicle power supply VB, another road is connected to SAE J1850+ lead-in wire through a resistance, and the drain electrode of triode Q3 is connected to SAE J1850+ lead-in wire through a diode;

The RXPWM lead-in wire is connected to the output terminal of operational amplifier N4A, and the power end of operational amplifier N4A is connected to vehicle power supply VB, earth terminal ground connection; The positive input terminal of operational amplifier N4A is connected to SAE J1850+ lead-in wire through a resistance, and the negative input end of operational amplifier N4A is connected to SAE J1850-lead-in wire through a resistance;

TXPWM-goes between and is connected to the base stage of triode Q4 through a resistance, and the collection utmost point of triode Q4 is connected to SAE J1850-lead-in wire, and the drain electrode of triode Q4 is divided into two-way, and the resistance of wherein leading up to is connected to SAE J1850+ lead-in wire, and another road is connected to ground;

The TXVPWM lead-in wire is connected to the positive input terminal of operational amplifier N4B, and the negative input end of operational amplifier N4B is divided into three the tunnel, and the resistance of wherein leading up to is connected to 5 volts of power Vcc; Another road is connected to ground through a resistance; Also have the negative input end of one tunnel concatenation operation amplifier N4C, the output terminal of operational amplifier N4B is divided into two-way, wherein; The resistance of leading up to is connected to 8 volts of power supply+8, and another road is connected to the base stage of triode Q5 through a resistance; The collection utmost point of triode Q5 is connected to 8 volts of power supply+8, and drain electrode is connected to SAE J1850+ lead-in wire through a diode;

The RXVPWM lead-in wire is connected to the output terminal of operational amplifier N4C, and the positive input terminal of operational amplifier N4C is connected to SAE J1850+ lead-in wire.

3. the multi-protocol data transducer that is used for automobile failure diagnosis according to claim 1 is characterized in that: the formation of said K line signal conditioning circuit is:

TXK goes between and is connected to the base stage of triode Q1 through a resistance, and the collection utmost point of triode Q1 divides two-way, and the resistance of wherein leading up to is connected to vehicle power supply VB, and another road is connected to the base stage of triode Q6, and the grounded drain of triode Q1 connects; The grounded drain of triode Q6 connects, and the collection utmost point of triode Q6 is divided into three the tunnel, and the resistance of wherein leading up to is connected to vehicle power supply VB, and another road is connected to the positive input terminal of operational amplifier N3A through a resistance, also has one the road to be connected to the K/K1 lead-in wire;

The RXK lead-in wire is connected to the output terminal of operational amplifier N3A, and the power end of operational amplifier N3A is connected to vehicle power supply VB, earth terminal ground connection; The negative input end of operational amplifier N3A is divided into three the tunnel, and wherein, the resistance of leading up to is connected to vehicle power supply VB, and another road is connected to ground through a resistance, also have one the road be connected to operational amplifier N3B negative input end;

The RXL lead-in wire is connected to the output terminal of operational amplifier N3B through a resistance; The positive input terminal of operational amplifier N3B is divided into three the tunnel after through a resistance, and the resistance of wherein leading up to is connected to vehicle power supply VB, and another road is connected to the L/K2 lead-in wire, also have one the road be connected to triode Q7 the collection utmost point;

TXL goes between and is connected to the base stage of triode Q2 through a resistance, and the collection utmost point of triode Q2 divides two-way, and wherein, the resistance of leading up to is connected to vehicle power supply VB, and another road is connected to the base stage of triode Q7, and the grounded drain of triode Q2 connects; The grounded drain of triode Q7.

4. the multi-protocol data transducer that is used for automobile failure diagnosis according to claim 1 is characterized in that: the formation of said CAN signal conditioning circuit is: the transmission data output end of CAN transceiver D3 is connected to CANTX lead-in wire, earth terminal ground connection; Power end is divided into two-way, wherein one the road is connected to 5 volts of power Vcc, and another road is connected to ground through an electric capacity; The Data Receiving input end is connected to the CANRX lead-in wire, and low level CAN bus end is divided into two-way, wherein one the road is connected to the CANL lead-in wire; Another road is connected to ground through a resistance and an electric capacity in order; High level CAN bus end is divided into two-way, and wherein, the one road is connected to the CANH lead-in wire; Another road is connected to ground through a resistance and an electric capacity in order, at a high speed/and the silent mode selecting side is connected to ground through a resistance.

5. the multi-protocol data transducer that is used for automobile failure diagnosis according to claim 1; It is characterized in that: the formation of said ALDL and RS232 signal conditioning circuit is: RS232 transceiver charge pump 1 anode is connected to RS232 transceiver charge pump 1 negative terminal through an electric capacity; RS232 transceiver power end is connected to 5 volts of power Vcc through an electric capacity; RS232 transceiver charge pump 2 anodes are connected to RS232 transceiver charge pump 2 negative terminals through an electric capacity; RS232 transceiver earth terminal is connected to ground through an electric capacity, and RS232 transceiver first passage R232 output end of main is connected to the RS232TX lead-in wire, and RS232 transceiver first passage R232 bus input end is connected to the RS232RX lead-in wire; RS232 transceiver first passage Data Receiving output terminal is connected to the TX lead-in wire; RS232 transceiver first passage data are sent output terminal and are connected to the RX lead-in wire, and RS232 transceiver second channel data are sent output terminal and are connected to the ALDLOUT lead-in wire, and RS232 transceiver second channel Data Receiving output terminal is connected to the ALDLIN lead-in wire; RS232 transceiver second channel R232 bus input end is connected to the ALDL lead-in wire through a resistance; RS232 transceiver second channel R232 output end of main is connected to the ALDL lead-in wire through a diode, and RS232 transceiver earth terminal is divided into two-way, wherein one the road is connected to ground; Another road is connected to 5 volts of power Vcc through an electric capacity, and RS232 transceiver power end is connected to 5 volts of power Vcc.

6. the multi-protocol data transducer that is used for automobile failure diagnosis according to claim 1 is characterized in that: the interface circuit of said microcontroller is: the reference voltage end of microcontroller is divided into two-way, wherein; The resistance of leading up to is connected to 5 volts of power Vcc, and another road is connected to ground through a resistance, and RA1 output/input end is connected to the TXPWM+ lead-in wire; RA2 output/input end is connected to the TXVPWM lead-in wire, and RA3 output/input end is connected to the RXL lead-in wire, and clock oscillation circuit I/O 1 end is divided into two-way; Wherein, the electric capacity of leading up to is connected to ground, and another road then is connected to crystal through another electric capacity; Clock oscillation circuit I/O 2 ends are divided into two-way, and wherein, the electric capacity of leading up to is connected to ground; Another road then is connected to crystal through another electric capacity, and RCO output/input end is connected to the RXVPWM lead-in wire, and RC1 output/input end is connected to the RXK lead-in wire; RC2 output/input end is connected to the RXPWM lead-in wire, and RC3 output/input end is connected to the TXVPWM-lead-in wire, and RC4 output/input end is connected to ground; RC4 output/input end is connected to ground, and data are sent output terminal and are connected to the TX lead-in wire, and the Data Receiving input end is connected to the RX lead-in wire; Earth terminal is connected to ground, and power end is divided into two-way, wherein one the road is connected to 5 volts of power Vcc; Another road is connected to ground through an electric capacity, and RBO output/input end is connected to the TXL lead-in wire, and RB1 output/input end is connected to the TXK lead-in wire; The CAN bus data sends output terminal and is connected to the CANRX lead-in wire, and the CAN bus data receives input end and is connected to the CANTX lead-in wire, and RB4 output/input end is connected to the ALDLOUT lead-in wire; RB5 output/input end is connected to the ALDLIN lead-in wire, and RB6 output/input end is connected to 5 volts of power Vcc through a resistance and a light emitting diode in order, and RB7 output/input end is connected to 5 volts of power Vcc through a resistance and a light emitting diode in order.

7. one kind is utilized the multi-protocol data transducer that is used for automobile failure diagnosis as claimed in claim 1 to carry out vehicle protocol search and its diagnosis processing method automatically, it is characterized in that, may further comprise the steps:

Start the vehicle protocol automatic search module in the microcontroller when (1) powering on, thereby carry out the employed communication protocol of search vehicle, and registration of vehicle protocol number DP_N, concern as follows with said DP_N value corresponding protocols:

DP_N=0, the agreement that this vehicle uses is the unsupported communication protocol of converter;

DP_N=1, the SAE J1850 communication protocol that the agreement that this vehicle uses is supported as converter;

DP_N=2, the ISO9141 communication protocol that the agreement that this vehicle uses is supported as converter;

DP_N=3, the ISO14230 communication protocol that the agreement that this vehicle uses is supported as converter;

DP_N=4, the ISO15765 communication protocol that the agreement that this vehicle uses is supported as converter;

DP_N=5, the SAE J1939 communication protocol that the agreement that this vehicle uses is supported as converter;

DP_N=6, the ALDL communication protocol that the agreement that this vehicle uses is supported as converter;

DP_N=7, the KW1281 communication protocol that the agreement that this vehicle uses is supported as converter;

(2) as if the vehicle protocol DP_N=0 of record, VD2 and two light emitting diodes of VD3 of then glimmering and be connected with microcontroller simultaneously are with the caution operator;

(3), then get into the RS232 signal conditioning circuit and wait for the state that receives diagnostic instruction if the vehicle protocol DP_N of record is not 0; When the RS232 signal conditioning circuit received instruction or data, whether first decision instruction or data met ISO14229, ISO15031-5 or the SAEJ1979 standard of vehicle connecting interface; If do not meet one of them of above-mentioned ISO14229, ISO15031-5 or SAEJ1979 standard, then feedback " request instruction is lack of standardization " information is carried out diagnostic process otherwise call the corresponding protocol diagnostic module according to the DP_N value, and one of following two kinds of situations are arranged;

(3-1) as if DP_N=1, DP_N=2, DP_N=3, DP_N=6 or DP_N=7, the diagnostic process submodule that then is embedded in the SAE J1850/ISO 9141/ISO 14230/KW1281/ALDL agreement in the controller carries out following diagnostic process according to the open interconnected pattern of OSI:

At first, receive the instruction of the application layer data UP_D form that meets ISO14229, ISO 15031-5 or SAE J1979 standard;

Then, the UP_D format order that receives is changed into the data that meet corresponding diagnosing protocol link layer data LP_D form and send to vehicle OBD system;

After having sent instruction, wait for the data that receive vehicle ECU response; Whenever be converted into the UP_D form after receiving the data of LP_D form of a response, and send response data through RS232;

When the stand-by period overflows, then withdraw from above-mentioned diagnostic process process;

(3-2) as if DP_N=4 or DP_N=5, the diagnostic process submodule that then is embedded in the ISO 15765/SAE J1939 agreement in the controller carries out following diagnostic process according to the open interconnected pattern of OSI:

At first, receive the instruction of the application layer data UP_D form that meets ISO14229, ISO 15031-5 or SAE J1979 standard;

Then, the UP_D format order that receives is changed into the data that meet corresponding diagnosing protocol link layer data LP_D form and send to vehicle OBD system;

After having sent instruction, wait for the data that receive vehicle ECU response; If the response data of single frames then directly is converted into the UP_D form with the LP_D formatted data that responds, and sends response data through RS232; If the multiframe response data stores after then earlier its multiframe response data being put in order according to ID, wait to wait until after whole message receives end again the LP_D formatted data that responds to be converted into the UP_D form, and send response data through RS232;

When the stand-by period overflows, withdraw from above-mentioned diagnostic process process.

Images