Vehicle fault diagnosis system

Abstract

The utility model belongs to a vehicle fault diagnosis system. A controller analyzes vehicle data transmitted by a vehicle-mounted data acquisition module to evaluate the state of a vehicle, controls an external sensor to acquire data, integrates sensor data and OBD information, and cooperates with a wireless communication module to realize two-way transmission of vehicle fault diagnosis information and the Internet; the vehicle-mounted data acquisition module is connected with the controller and is used for acquiring the automobile driving state and fault diagnosis information and transmitting the information to the controller; the air quality sensor is connected with the controller and used for detecting the exhaust emission condition of the automobile; the ultrasonic sensor is connected with the controller and used for detecting the closing state of the vehicle window; and the temperature sensor is connected with the controller and used for detecting the temperature state of the power battery. The utility model solves the problem of the traditional interface, improves the efficiency of the system and the OBD interface, obtains multiple information of the vehicle, and is externally connected with the sensor for detection. The cloud platform facilitates data processing and storage, the mobile phone facilitates query and diagnosis, and user experience and safety are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to diagnostic system technical field, concretely, especially relates to a vehicle fault diagnosis system. BACKGROUND

[0002] In the process of continuous development of automobile technology, the on-board diagnostics (OBD) has been widely popularized and has become an indispensable part of the regulatory standards. With its powerful functions, the OBD system can monitor various states of the vehicle in real time and accurately during driving, diagnose potential faults in a timely manner, and output detailed information related to it, thereby playing a crucial role in driving warning, safe driving, and vehicle maintenance in multiple key areas.

[0003] However, with the continuous evolution of technology, the OBD system also faces some problems to be solved. Although the vehicle-mounted OBD interface supports up to 8 data communication protocols, the existing OBD information reading terminal has obvious shortcomings. In order to realize the connection with the automobile OBD interface, the reading terminal needs to specially configure various special interfaces to match different communication protocols, which greatly restricts the flexibility and convenience of the OBD interface in actual application and limits the further expansion of its application range.

[0004] Under the current technical pattern, the existing technical solutions have many shortcomings. For example, the solutions proposed by Tu Yu, Zhang Fengdeng, and Dan Binghua in "Design and Implementation of Automotive OBD Internet of Things" (Electronic Measurement Technology, Vol. 39, No. 8, 2016, pp. 32-36) and Zhang Kai in "Innovative Design of Ultrasonic Distance Detection Based on Internet+" (Modern Electronic Technology, Vol. 5, 2017, pp. 163-165) successfully realized the communication between the vehicle-mounted OBD and the mobile phone, as well as the communication between the mobile phone and the public network, but still exposed the following problems in actual application:

[0005] Firstly, the fault detection range it can realize is relatively limited, and there are obvious deficiencies in the detection of traditional cars and new energy cars, and it cannot comprehensively cover various fault conditions that may occur in cars. Secondly, as the key equipment for data storage and transmission, the data storage capacity of the mobile phone is difficult to meet the growing storage demand of automobile fault diagnosis data, which to some extent affects the analysis and utilization ability of the system on historical data; thirdly, when the mobile phone works as a relay station for data transmission, the working speed cannot meet the requirements of high efficiency and stability, which easily leads to data transmission delay or interruption, affecting the real-time and reliability of the system; most importantly, these existing technical solutions can only communicate with the CAN protocol of the OBD port, and cannot establish effective connection with other multiple protocols of the OBD port, which seriously affects the application efficiency of the whole system, so that the system cannot fully exert its potential, and cannot provide more comprehensive and efficient solutions for automobile fault diagnosis. Practical new type content

[0006] In order to make up for the deficiencies of the prior art and solve at least one technical problem proposed in the background art, the utility model provides a vehicle fault diagnosis system, aiming at the working efficiency problem of the vehicle-mounted OBD online fault diagnosis system, designing a bidirectional communication interface with the vehicle-mounted OBD-II port, realizing online communication covering all 8 kinds of data communication protocols of the OBD-II port, externally connecting various sensors and through a cloud platform, designing a bidirectional communication interface with the Internet, realizing online high-speed and large-capacity data communication and storage of fault diagnosis information and the Internet, and finally feeding back fault data to a mobile phone APP, realizing an intelligent and networked automobile fault online detection monitoring and diagnosis platform Internet of Things management mode.

[0007] The technical scheme adopted by the utility model to solve its technical problems is: the utility model discloses a vehicle fault diagnosis system, which comprises a user end, the user end comprises

[0008] A controller analyzes automobile data transmitted by the vehicle-mounted data acquisition module to evaluate the vehicle state, controls external sensor data acquisition, integrates sensor data and OBD information, and cooperates with a wireless communication module to realize bidirectional transmission of vehicle fault diagnosis information and the Internet; a vehicle-mounted data acquisition module is connected with the controller and is used for acquiring automobile driving state and fault diagnosis information and transmitting to the controller;

[0009] A wireless communication module is connected with the controller and is used for connecting with a cloud platform, uploading vehicle fault diagnosis data processed by the controller to the cloud platform, and receiving data issued by the cloud platform; a power management system is used for power supply of the vehicle fault diagnosis system;

[0010] An air quality sensor is connected to the controller for detecting the exhaust emission condition of the vehicle; an ultrasonic sensor is connected to the controller for detecting the closed state of the vehicle window; and a temperature sensor is connected to the controller for detecting the temperature state of the power battery.

[0011] Further, the vehicle fault diagnosis system further comprises a network end, wherein the network end comprises a cloud platform, and the cloud platform is used for receiving and processing the data uploaded by the user end,

[0012] A mobile phone APP is used for showing the vehicle driving state and fault information to the user and receiving the user instruction.

[0013] Further, the controller is an STM32F103C8T6 single-chip microcomputer, the vehicle-mounted data acquisition module is an OBD connector ELM327 module, and the wireless communication module is a WIFI wireless internet ESP8266 module.

[0014] Further, the WIFI wireless internet ESP8266 module is connected to the serial communication port of the STM32F103C8T6 single-chip microcomputer through a MAX232 module, is linked to the host computer end of the remote network server in a SoftAP mode, and is used for uploading the vehicle fault diagnosis information processed by the STM32F103C8T6 single-chip microcomputer to the cloud platform and receiving the data transmission from the cloud platform to the STM32F103C8T6 single-chip microcomputer.

[0015] Further, the air quality sensor, the ultrasonic sensor and the temperature sensor are respectively used for collecting the exhaust emission condition of the vehicle, the closed state of the vehicle window and the temperature state of the power battery, and transmitting the data to the STM32F103C8T6 single-chip microcomputer.

[0016] Further, the power management system obtains the voltage from the vehicle-mounted OBD port, and provides the working voltage for the STM32F103C8T6 single-chip microcomputer, the ESP8266 module and the entire vehicle fault diagnosis system.

[0017] Further, the power management system comprises an LM7805 voltage stabilizer and an LM2596S voltage reduction stabilizing circuit, and provides the adaptive working voltage for the STM32F103C8T6 single-chip microcomputer and the ESP8266 module.

[0018] Further, the STM32F103C8T6 single-chip microcomputer is connected to the OBD connector ELM327 module through a serial communication interface, and is used for receiving the vehicle engine load, the fuel system state, the coolant temperature, the rotating speed, the vehicle speed and the fault code information.

[0019] Further, the CH-PD pin of the WIFI wireless Internet ESP8266 module is connected with VCC, and level conversion and information interaction are realized between the WIFI wireless Internet ESP8266 module and the STM32F103C8T6 single-chip microcomputer.

[0020] The utility model discloses the advantages are in:

[0021] 1) the system can realize two -way communication with the vehicle OBD -II port, covers its all 8 kinds of data communication protocol, effectively solved the traditional OBD information reading terminal need to configure multiple special interface matching different protocol problem, improved the compatibility and adaptability of system, greatly promoted the application efficiency of OBD interface;

[0022] 2) through the interface circuit of reasonable design, such as the connection between STM32F103C8T6 single-chip microcomputer and ELM327, ESP8266 module realizes stable and efficient data transmission, ensures that vehicle operating state parameter and fault diagnosis information can be acquired and transmission in time accurately;

[0023] 3) not only can obtain the common operating state data (such as engine load, speed, vehicle speed etc.) and fault diagnosis code provided by the vehicle OBD -II system, but also realizes the detection of automobile exhaust emission condition, car window closing state, power battery temperature state etc. through external air quality sensor, ultrasonic sensor and temperature sensor etc., greatly expands the range and depth of fault detection, can more comprehensively grasp the overall condition of vehicle;

[0024] 4) using the powerful computing and storage capacity of cloud platform, realizes the online high speed, large capacity data communication and storage of fault diagnosis information and internet, compared with the traditional data storage mode relying on mobile phone, cloud platform can handle and store more data, is convenient for subsequent data analysis and traceability, provides strong support for the long -term health management of vehicle;

[0025] 5) the user can conveniently inquire automobile operating real -time data and fault information through mobile phone APP, understands vehicle state at any time and anywhere, need not rely on professional equipment or go to specific place and detect, realizes intelligent, networked automobile fault online detection monitoring diagnosis mode, improves the user's control feeling and convenience to vehicle state;

[0026] 6) the system can monitor vehicle state in real time, can send early warning to the user through mobile phone APP in time once detecting fault or abnormal condition, reminds the user to take corresponding measures, helps to improve driving safety, avoids potential safety hazard, provides more reliable guarantee for the user's travel;

[0027] 7)Helps to detect automobile faults, the number of detected faults is large, the cost performance is high, real-time monitoring can be realized by using a mobile phone APP, can be widely applied to low-end cars, old cars, automobile 4S stores, automobile repair stores, various types of car owners, etc., and has the advantages of convenience and practicality. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0029] Figure 1 is a system structure diagram of the present application;

[0030] Figure 2 is an internal structure diagram of the ELM327 module;

[0031] Figure 3 is a schematic diagram of the OBD-I standard communication interface end pin of the vehicle;

[0032] Figure 4 is a schematic diagram of the interface between the single-chip microcomputer and the ELM327 and ESP8266 realized by the MAX232;

[0033] Figure 5 is a DS18B20 temperature sensor principle diagram;

[0034] Figure 6 is an MQ gas sensor principle diagram;

[0035] Figure 7 is an ultrasonic wave HC-SR04 module principle diagram;

[0036] Figure 8 is an ESP8266 pin and RS232 configuration schematic diagram;

[0037] Figure 9 is the interface between the single-chip microcomputer and the ELM327 and ESP8266 realized by the MAX232;

[0038] Figure 10 is a power supply system of two voltage levels of the user end. DETAILED DESCRIPTION

[0039] Clearly and completely describe the technical scheme in the embodiments of the utility model with the drawings in the embodiments of the utility model below, obviously, the described embodiments are only a part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the ordinary skill in the art without creative labor belong to the scope of the utility model protection.

[0040] A vehicle fault diagnosis system comprises a user end, the user end comprises

[0041] A controller analyzes the automobile data transmitted by the vehicle-mounted data acquisition module to evaluate the vehicle state, controls the data acquisition of the external sensor, integrates the sensor data and OBD information, cooperates with the wireless communication module to realize the bidirectional transmission of vehicle fault diagnosis information and the Internet; a vehicle-mounted data acquisition module is connected with the controller, used for acquiring the automobile driving state and fault diagnosis information and transmitting to the controller;

[0042] A wireless communication module is connected with the controller, used for connecting with the cloud platform, uploading the vehicle fault diagnosis data processed by the controller to the cloud platform, and receiving the data issued by the cloud platform; a power management system is used for power supply of the vehicle fault diagnosis system;

[0043] An air quality sensor is connected with the controller, used for detecting the automobile exhaust emission condition; an ultrasonic sensor is connected with the controller, used for detecting the car window closing state; a temperature sensor is connected with the controller, used for detecting the power battery temperature state.

[0044] The vehicle fault diagnosis system further comprises a network end, the network end comprises

[0045] A cloud platform is used for receiving and processing the data uploaded by the user end,

[0046] A mobile phone APP is used for showing the automobile driving state and fault information to the user and receiving the user instruction.

[0047] The controller is an STM32F103C8T6 single-chip microcomputer, the vehicle-mounted data acquisition module is an OBD connector ELM327 module, and the wireless communication module is a WIFI wireless internet ESP8266 module.

[0048] The WIFI wireless internet ESP8266 module is connected with the serial communication port of the STM32F103C8T6 single-chip microcomputer through the MAX232 module, links with the remote network server host computer end in the SoftAP mode, used for uploading the vehicle fault diagnosis information processed by the STM32F103C8T6 single-chip microcomputer to the cloud platform, and receiving the data transmission from the cloud platform to the STM32F103C8T6 single-chip microcomputer.

[0049] The air quality sensor, ultrasonic sensor and temperature sensor are used for collecting automobile exhaust emission condition, vehicle window closing state and power battery temperature state data respectively, and transmitting the data to the STM32F103C8T6 single-chip microcomputer.

[0050] The power management system obtains voltage from the vehicle-mounted OBD port, and provides working voltage for the STM32F103C8T6 single-chip microcomputer, the ESP8266 module and the whole vehicle fault diagnosis system.

[0051] The power management system comprises an LM7805 voltage stabilizer and an LM2596S voltage reduction stabilizing circuit, and provides adaptive working voltage for the STM32F103C8T6 single-chip microcomputer and the ESP8266 module.

[0052] The STM32F103C8T6 single-chip microcomputer is connected with the OBD connector ELM327 module through a serial communication interface, and is used for receiving vehicle engine load, fuel system state, coolant temperature, rotating speed, vehicle speed and fault code information.

[0053] The CH-PD pin of the WIFI wireless network ESP8266 module is connected with VCC, and level conversion and information interaction are realized between the WIFI wireless network ESP8266 module and the STM32F103C8T6 single-chip microcomputer.

[0054] Further described in detail with reference to the drawings

[0055] The system structure of the utility model is as shown in Figure 1 The user end is composed of an OBD connector ELM327 module, a WIFI wireless network ESP8266 module, an air quality sensor, an ultrasonic sensor, a temperature sensor and a power management system, and the network end is composed of a cloud platform.

[0056] ELM327 is a special integrated circuit module produced by ELM company, and realizes connection and communication with the vehicle-mounted OBD-II port; the pin of the automobile information input port of the ELM327 connector is connected with the vehicle-mounted OBD-II interface socket through a small amount of circuit, the module is powered by the No. 16 pin of the vehicle-mounted OBD-II interface, after the ELM327 connector and the vehicle-mounted OBD exchange information, the data transceiver RXD and TXD are communicated with the single-chip microcomputer interface, after the single-chip microcomputer receives the ELM327 signal, information processing is carried out, and the WIFI wireless network ESP8266 module is linked with the cloud platform.

[0057] ESP8266 is a special integrated circuit module, with wireless WiFi and Internet link function, realize the interface link of wireless WiFi and Internet, with low power consumption, powerful processing capability, realize the function of wireless WiFi online, is widely used in the design and application of Internet of Things.

[0058] The air quality sensor, the ultrasonic sensor and the DS18B20 temperature sensor are external sensors, which are used for detecting tail gas emission conditions of the automobile, a closed state of the vehicle window, a temperature state of the power battery and the like.

[0059] The network end is composed of a cloud server and a mobile phone APP.

[0060] Interface design of STM32F103C8T6 single-chip microcomputer and ELM327

[0061] As shown in the internal structure of ELM327, Figure 2 The user end of the utility model takes STM32F103C8T6 single-chip microcomputer as a controller. The STM32F103C8T6 single-chip microcomputer produced by STM company is a new generation of 8051 single-chip microcomputer, has the characteristics of wide voltage and low power consumption and high speed and super strong anti-interference ability, is internally integrated with high-precision RC clock, does not need to be externally connected with a crystal oscillator circuit, and only needs to be set when solidifying an application program. The clock set by the user end STM32F103C8T6 single-chip microcomputer is 11.0592MHz. The main components in the STM32F103C8T6 include 8-way high-speed 10-bit A / D conversion, 8-way 10-bit PWM and 2 groups of independent asynchronous serial communication interfaces. The 2 groups of independent asynchronous serial communication interfaces of the STM32F103C8T6 single-chip microcomputer meet the needs of the 2-way serial communication interfaces of the system, one of which is connected with the ELM327 interface, and the other is connected with the ESP8266 interface. The ELM327 special integrated circuit is the latest vehicle-mounted OBD-II general automobile diagnostic information communication interface module, and the vehicle-mounted OBD-II system realizes bidirectional communication with the ELM327 through the OBD-II interface and the ELM327 for real-time monitoring and diagnosis of the state and various faults during vehicle driving.

[0062] The OBD-II system in the vehicle monitors and diagnoses various working conditions and faults in real time during the driving process. The main information data of the real-time monitoring and diagnosis includes engine load value, fuel system state, short-term fuel condition, coolant temperature, engine speed (RPM), vehicle speed, intake manifold pressure, injection advance time, intake temperature, air flow speed, intake valve absolute position, fuel pressure, fuel consumption monitoring, and various fault diagnosis codes. The Society of Automotive Engineers (SAE) has specified eight protocols for the communication between the OBD-II port in the vehicle and the user terminal, i.e., ISO9141, KWP2000, SAE J1850 (PWM), SAE J1850 (VPW), CAN, etc. The pin of the standard communication interface of the OBD-II in the vehicle is shown in Table 1. Figure 3 The ELM327 module supports the eight data communication protocols of the OBD-II port. The ELM327 module can realize the interface with the OBD-II port in the vehicle by using only a small amount of external auxiliary circuits, can automatically identify all OBD communication protocols, and can automatically switch the protocols. The pin definition of the standard communication interface of the OBD-II in the vehicle is shown in Table 1.

[0063]

[0064] Table 1

[0065] The ELM327 CMOS design has a low power consumption characteristic, supports RS232 through a universal serial port, uses PDIP and SOIC packaging, and is powered by 12V. The communication baud rate of the ELM327 can be set to 9600 or 38400. The interface between the STM32F103C8T6 single-chip microcomputer and the ELM327 is shown in Table 1. Figure 4

[0066] Design of the STM32F103C8T6 single-chip microcomputer and various external sensors

[0067] The external sensor application of the utility model includes an air quality sensor, an ultrasonic sensor, a DS18B20 temperature sensor, etc.

[0068] ​The temperature sensor adopts DS18B20, and the temperature of the power battery is detected in real time. The temperature conversion time of the digital temperature sensor of the temperature detection circuit is relatively long. The higher the resolution of the digital temperature sensor, the longer the data conversion time required for displaying the temperature. Therefore, in actual application, the resolution and conversion time should be considered. The first to fifth bytes of the high-speed temporary memory RAM are used, and the remaining bytes are kept in an unused state, and the remaining bytes display complete logical 1. Before the ninth byte is read out, the CRC code of all 8 bytes of the high-speed temporary memory RAM will be used to check the data. After the DS18B20 receives the temperature conversion command, the conversion command is started. After the conversion is completed, the temperature value of the digital temperature sensor is stored in the first and second bytes of the high-speed temporary memory. When the sign bit S is equal to zero, the digital temperature sensor displays the measured temperature value as greater than zero, and the binary bit can be directly converted into decimal; when the sign bit S is a non-zero value, the digital temperature sensor displays the measured temperature value as less than zero. The DS18B20 mainly has a 64-bit ROM. After the digital temperature sensor completes the temperature conversion, the 2-byte temperature output register and the 1-byte upper and lower alarm register (TH and TL) of the DS18B20 compare the temperature value measured by the sensor with the TH and TL byte contents in the RAM. When the measured temperature value is greater than the set TH or the temperature value is less than the set TL, the alarm flag in the DS18B20 is set, and the host computer responds to the alarm search command. The cyclic redundancy check code (CRC) is stored in the most significant byte of the 64-bit ROM. The first 56 bits of the host computer ROM are used to calculate the cyclic redundancy check code value, and the cyclic redundancy check code value stored in the DS18B20 is compared. The circuit principle diagram is as follows Figure 5 as shown.

[0069] The air quality sensor adopts an MQ gas sensor, which detects the exhaust emission of the automobile in real time. That is, the gas sensitive material used by the MQ gas sensor is tin dioxide (Sn02) with low electrical conductivity in clean air. When the sensor is in an environment containing flammable gas, the electrical conductivity of the sensor increases with the increase of the concentration of flammable gas in the air. The change of electrical conductivity can be converted into an output signal corresponding to the gas concentration by using a simple circuit. The MQ gas sensor has high sensitivity to methane, and also has good sensitivity to propane and butane. This sensor can detect a variety of flammable gases, and is a low-cost sensor suitable for a variety of nutrients.

[0070] MQ gas sensor adopts high-quality double-sided panel design, has power indication and TTL signal output indication, has DO switch signal (TTL) output and AO analog signal output; the effective signal of TTL output is low level. (When the output is low level, the signal light is bright, which can be directly connected to a single-chip microcomputer or a relay module) The voltage of analog output is higher, and the higher the concentration is, the higher the voltage is. It has good sensitivity for detecting methane and natural gas. Four screw holes are provided for positioning; the product size is: 32 (L) * 20 (W) * 22 (H) It has long service life and reliable stability, fast response and recovery characteristics. The schematic diagram is as shown in Figure 6 .

[0071] The ultrasonic sensor adopts an HC-SR04 module. Ultrasonic wave is a kind of sound with high frequency and strong directivity. The principle of ultrasonic ranging is to measure the time of ultrasonic wave reflected by an obstacle after being emitted, and to calculate the actual distance from the emitting point to the obstacle according to the time difference between emission and reception. A high level of 10US is emitted from the control port, and the receiving port waits for the high level output. Once the output is obtained, the timer can be started. When the port becomes low level, the value of the timer can be read, which is the time of this ranging, and the distance can be calculated. In the utility model, it is used for detecting the closing state of the vehicle window. The schematic diagram is as shown in Figure 7 .

[0072] Interface design of STM32F103C8T6 single-chip microcomputer and ESP8266

[0073] The wireless WiFi module ESP8266 has a built-in IEEE802.11 protocol stack and a TCP / IP protocol stack, has a UART asynchronous serial communication interface port, supports a serial transparent data transmission link port, has a wireless WiFi link function, realizes the link between the user end and the Internet end, and supports SoftAP, Station and SoftAP+Station three networking modes. In the process of network communication, the conversion between serial data signals and wireless network data signals is realized. The networking mode designed in the user end adopts the SoftAP mode, and this mode is that the ESP8266 is linked to the remote network server host computer end as a wireless router, so as to realize the direct link between the user end and the network end.

[0074] The pin and RS232 configuration of the wireless WiFi module ESP8266 are as follows Figure 8As shown, by configuring the ESP8266 serial port, the WiFi module ESP8266 serial port level conversion, level matching is realized by MAX232, and the STM32F103C8T6 single-chip microcomputer serial port realizes the transceiving bidirectional communication interface. When the CH-PD in the ESP8266 module is at a low level, the internal power supply module is in a closed state, and when the CH-PD is at a high level, it is in a normal power supply working state, so the CH-PD pin of the ESP8266 module needs to be connected with the VCC. The RXD and TXD serial port end pins of the user's STM32F103C8T6 single-chip microcomputer are realized by the MAX232 module to realize the interface design with the wireless WiFi module ESP8266. The MAX232 module realizes the level conversion between the 5V level of the single-chip microcomputer and the 3.3V level of the wireless WiFi module ESP8266, and also realizes the information communication interface between the single-chip microcomputer and the wireless WiFi module ESP8266. The STM32F103C8T6 single-chip microcomputer realizes the data communication interface between the wireless WiFi module ESP8266 through the MAX232 as shown in Figure 9 .

[0075] Power system design

[0076] The user's power supply system provides two voltage levels of 5V and 3.3V, respectively, for the single-chip microcomputer and the ESP8266. The user's direct-current stabilized power supply of two voltage levels is as shown in Figure 10 . Among them, the 5V direct-current stabilized power supply is composed of a filter, an LM7805 stabilizer, etc., and provides +12V voltage through the vehicle-mounted OBD port (OBD port 16 pin), and the LM7805 realizes 5V direct-current voltage for the single-chip microcomputer. The 3.3V direct-current stabilized power supply adopts LM2596S (+3.3V) to complete the process of voltage reduction and stabilization, and provides stable 3.3V voltage for the ESP8266 system. Among them, D1 is used to prevent reverse connection of the power supply, and C1-C8 are power supply filters. The LM2596S is a switching type voltage reduction and stabilization circuit, with a switching frequency of up to 150kHz, good wave ripple, linear and load regulation characteristics, high conversion efficiency, standby control, overheat protection and current limiting protection functions, and the LM2596S power voltage is reduced from the original 5V to 3.3V stable voltage for the ESP8266 power supply. The ELM327 is powered by the OBD port 16 pin.

[0077] The utility model technology can also be used for fault detection in the fields of trucks, bread, motorcycles, electric vehicles and the like.

[0078] The working principle of the utility model comprises the following steps

[0079] I. Vehicle-mounted OBD-II system data acquisition and transmission

[0080] 1. Data monitoring and acquisition

[0081] The OBD-II system in the vehicle monitors various working conditions and fault information in real time during the driving process, which includes engine load value, fuel system status, coolant temperature, engine speed, vehicle speed, intake manifold pressure, injection advance time, intake air temperature, air flow speed, intake valve absolute position, fuel pressure, fuel consumption monitoring, and various fault diagnosis codes; the OBD-II system in the vehicle communicates with the ELM327 module through its standard communication interface (supporting 8 protocols such as ISO9141, KWP2000, SAEJ1850 (PWM), SAEJ1850 (VPW), CAN, etc.) to transmit the above data to the ELM327 module.

[0082] 2. ELM327 module processing and forwarding

[0083] The ELM327 module, as an application-specific integrated circuit, has the ability to automatically identify all OBD communication protocols and automatically switch protocols. After receiving the data transmitted by the OBD-II system in the vehicle, it performs preliminary processing; then the ELM327 module transmits the processed data to the STM32F103C8T6 microcontroller through its data transceiver port (RXD, TXD). The communication between it and the microcontroller is realized through the MAX232 module to realize level conversion (convert the 12V level of the ELM327 module to the 5V level suitable for the microcontroller) and serial data communication interface function, to ensure accurate data transmission.

[0084] II. External sensor data acquisition and transmission

[0085] 1. Temperature sensor (DS18B20)

[0086] The temperature sensor DS18B20 detects the temperature of the power battery in real time. When receiving the temperature conversion command issued by the STM32F103C8T6 microcontroller, it starts the conversion process. After the conversion is completed, the temperature value is stored in the first and second bytes of its internal high-speed temporary storage memory. The sensor compares the measured temperature value with the contents of the internal upper and lower alarm registers (TH and TL), and if the measured temperature value is greater than TH or less than TL, the alarm flag is set and responds to the alarm search command issued by the host.

[0087] Finally, the temperature data is transmitted to the STM32F103C8T6 microcontroller through the data pin, and the microcontroller processes and analyzes the temperature data according to the preset program.

[0088] 2. Air quality sensor (MQ gas sensor)

[0089] MQ gas sensor utilizes the characteristic of gas sensitive material (tin dioxide) that the conductivity changes in the environment of flammable gas to detect the exhaust emission of automobile. When there is flammable gas in the environment of the sensor, the conductivity increases with the increase of the concentration of the gas, and the change of the conductivity is converted into the corresponding output signal (DO switch signal or AO analog signal) through a simple circuit; the sensor has high sensitivity to various flammable gases such as methane, and the output signal (such as TTL output active signal is low level, and the analog output voltage increases with the increase of the concentration) is transmitted to the STM32F103C8T6 single-chip microcomputer, and the single-chip microcomputer judges whether the exhaust emission is over standard and the like according to the signal.

[0090] 3. Ultrasonic sensor (HC-SR04 module)

[0091] When used for detecting the closed state of the window, the STM32F103C8T6 single-chip microcomputer controls the control port of the HC-SR04 module to send a high level signal of more than 10US, triggering the ultrasonic wave emission; the ultrasonic wave propagates in the air and is reflected back when encountering the window (obstacle), and the receiving port of the sensor waits for the high level output, and once the high level of the reflected wave is received, the timer is started, and when the receiving port becomes low level, the value of the timer is read, which is the time of the ultrasonic wave going back and forth. According to the propagation speed of the ultrasonic wave in the air (known), the actual distance from the emission point to the window can be calculated. Then the distance data is transmitted to the single-chip microcomputer, and the single-chip microcomputer judges whether the window is in the normal closed state.

[0092] Three, data integration and processing (STM32F103C8T6 single-chip microcomputer)

[0093] 1. Data receiving and summarizing

[0094] The STM32F103C8T6 single-chip microcomputer receives the vehicle running state and fault information data from the vehicle-mounted OBD-II system through the serial communication port connected with the ELM327 module, and receives the data from the external sensor (temperature, air quality, ultrasonic sensor) through the corresponding interface.

[0095] 2. Data processing and analysis

[0096] The single-chip microcomputer integrates, analyzes and processes the received data. For example, whether the temperature data is within the normal range, whether the air quality data meets the standard of exhaust emission, whether the distance data measured by the ultrasonic sensor is normal, and the like. At the same time, combined with the fault diagnosis code and other information transmitted by the vehicle-mounted OBD-II system, the overall running condition of the vehicle is comprehensively judged.

[0097] 3. Data transmission preparation

[0098] The processed comprehensive data is subjected to format conversion and other operations in the single-chip microcomputer, and is prepared to be transmitted to the ESP8266 module through another serial communication port.

[0099] Four, data transmission to the cloud platform (ESP8266 module)

[0100] 1. Serial data conversion and transmission

[0101] The STM32F103C8T6 single-chip microcomputer transmits the processed data to the ESP8266 module. During the transmission process, the MAX232 module is used to realize level conversion (convert the 5V level of the single-chip microcomputer to the 3.3V level suitable for the ESP8266 module), and at the same time, complete the information communication interface function between the single-chip microcomputer and the ESP8266 module.

[0102] The ESP8266 module has a built-in IEEE802.11 protocol stack and TCP / IP protocol stack, and has a UART asynchronous serial communication interface port. It converts the received serial data signal into a wireless network data signal.

[0103] 2. Wireless WiFi link and data upload

[0104] According to the SoftAP networking mode designed by the user end, the ESP8266 module is linked to the remote network server (cloud platform) host computer end as a wireless router, realizing the direct link between the user end and the network end, and uploading the vehicle data to the cloud platform.

[0105] Five, cloud platform fault diagnosis and information feedback

[0106] 1. Fault diagnosis and data processing

[0107] After receiving the data from the vehicle end, the cloud platform uses its powerful computing and storage capabilities to conduct in-depth assessment of the vehicle's running state according to the preset fault diagnosis algorithm and rules. Through analysis and comparison of a large amount of historical data, it can more accurately determine whether the vehicle has a fault, the type of fault and the severity.

[0108] 2. Information feedback to mobile phone APP

[0109] The cloud platform feeds back the fault diagnosis results and real-time running data of the vehicle (including normal running data) to the mobile phone APP through the Internet. Users can open the mobile phone APP at any time to check the detailed running state of the car, including sensor data, vehicle state information monitored by the OBD system, and whether there is a fault and fault details, etc.

[0110] Six, system continuous operation and monitoring

[0111] 1. Circulating monitoring

[0112] The entire system continuously repeats the above data acquisition, transmission, diagnosis and feedback process, realizes real-time and continuous monitoring of the vehicle state, and ensures that any abnormal situation during vehicle operation can be found in time.

[0113] 2. Early warning and maintenance reminder

[0114] When the system detects a serious fault or abnormal situation, the cloud platform can trigger the corresponding early warning mechanism according to the preset rules, such as pushing an emergency notification (including sound, pop-up window, etc. Reminder method) to the mobile phone APP, reminding the user to take timely measures, such as stopping the car for inspection, going to the repair shop, etc. At the same time, the system can also provide regular maintenance reminders and other services to the user according to the running status and maintenance period of the vehicle, helping the user to better maintain the vehicle and prolong the service life of the vehicle.

[0115] The above shows and describes the basic principle, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above embodiments, and the above embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A vehicle trouble diagnosis system comprising a user terminal, characterized by comprising: The user terminal comprises a controller, which parses automobile data from a vehicle-mounted data acquisition module to evaluate a vehicle state, controls external sensor data acquisition, integrates sensor data and OBD information, and cooperates with a wireless communication module to realize two-way transmission of vehicle fault diagnosis information and the Internet; the vehicle-mounted data acquisition module is connected to the controller and is used to acquire automobile driving state and fault diagnosis information and transmit them to the controller; The wireless communication module is connected to the controller and is used to connect to a cloud platform, upload vehicle fault diagnosis data processed by the controller to the cloud platform, and receive data issued by the cloud platform; A power management system is used to supply power to the vehicle fault diagnosis system; An air quality sensor is connected to the controller and is used to detect automobile exhaust emission conditions; an ultrasonic sensor is connected to the controller and is used to detect a vehicle window closing state; and a temperature sensor is connected to the controller and is used to detect a power battery temperature state.

2. The vehicle malfunction diagnosis system according to claim 1, characterized by: The vehicle fault diagnosis system further comprises a network terminal, which comprises A cloud platform, which is used to receive and process data uploaded by the user terminal, A mobile phone APP, which is used to show automobile driving state and fault information to a user and receive user instructions.

3. The vehicle malfunction diagnosis system according to claim 1, characterized by: The controller is an STM32F103C8T6 single-chip microcomputer, the vehicle-mounted data acquisition module is an OBD connector ELM327 module, and the wireless communication module is a WIFI wireless Internet ESP8266 module.

4. The vehicle malfunction diagnosis system according to claim 3, characterized by: The WIFI wireless Internet ESP8266 module is connected to a serial communication port of the STM32F103C8T6 single-chip microcomputer through a MAX232 module, links to a remote network server host computer end in a SoftAP mode, and is used to upload vehicle fault diagnosis information processed by the STM32F103C8T6 single-chip microcomputer to a cloud platform and receive data from the cloud platform and transmit them to the STM32F103C8T6 single-chip microcomputer.

5. The vehicle malfunction diagnosis system according to claim 4, characterized by: The air quality sensor, the ultrasonic sensor, and the temperature sensor are respectively used to acquire automobile exhaust emission condition data, vehicle window closing state data, and power battery temperature state data and transmit them to the STM32F103C8T6 single-chip microcomputer.

6. The vehicle malfunction diagnosis system according to claim 5, characterized by: The power management system acquires voltage from a vehicle-mounted OBD port and provides working voltage for the STM32F103C8T6 single-chip microcomputer, the ESP8266 module, and the entire vehicle fault diagnosis system.

7. The vehicle malfunction diagnosis system according to claim 6, characterized by: The power management system comprises an LM7805 voltage stabilizer and an LM2596S voltage reduction stabilizing circuit, which respectively provide adaptive working voltage for the STM32F103C8T6 single-chip microcomputer and the ESP8266 module.

8. The vehicle malfunction diagnosis system according to claim 7, characterized by: The STM32F103C8T6 single-chip microcomputer is connected to the OBD connector ELM327 module through a serial communication interface and is used to receive vehicle engine load, fuel system state, coolant temperature, speed, vehicle speed, and fault code information.

9. The vehicle malfunction diagnosis system according to claim 8, characterized by: A CH-PD pin of the WIFI wireless Internet ESP8266 module is connected to VCC, and level conversion and information interaction are realized between the WIFI wireless Internet ESP8266 module and the STM32F103C8T6 single-chip microcomputer.

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