WO2021179992A1

WO2021179992A1 - Disconnection detection method for obd module, obd vehicle-mounted monitoring terminal, obd monitoring system

Info

Publication number: WO2021179992A1
Application number: PCT/CN2021/079167
Authority: WO
Inventors: 王维林
Original assignee: 深圳市道通科技股份有限公司
Priority date: 2020-03-12
Filing date: 2021-03-04
Publication date: 2021-09-16
Also published as: CN111426984A; CN111426984B

Abstract

A disconnection detection method for an OBD module (101), an OBD vehicle-mounted monitoring terminal (10) and an OBD monitoring system. The method comprises that: a MCU (102) detects whether communication between the OBD module (101) and an electronic control unit on a vehicle is abnormal; if so, then the MCU (102) determines whether the vehicle supports a high-speed CAN communication protocol; if the vehicle supports the high-speed CAN communication protocol, then the MCU (102) detects whether a CAN circuit between the OBD module (101) and the electronic control unit on the vehicle is turned on; if not, the MCU (102) sends a disconnection warning of the OBD module (101) to a background management server (30) so as to warn that the communication between the OBD module (101) and the electronic control unit of the vehicle is disconnected. The method may more accurately detect whether the communication between the OBD module (101) and the electronic control unit of the vehicle is disconnected, and may prevent the non-malicious pulling out of the OBD vehicle-mounted monitoring terminal (10) from being mistakenly identified as a malicious pulling out situation, thus improving the accuracy of disconnection detection for the OBD module (101).

Description

OBD module disconnection detection method, OBD vehicle monitoring terminal, OBD monitoring system

This application requires the priority of a Chinese patent application filed with the Chinese Patent Office on March 12, 2020, the application number is 202010171250.7, and the application name is "OBD module disconnection detection method, OBD vehicle monitoring terminal, OBD monitoring system", all of which The content is incorporated in this application by reference.

Technical field

This application relates to the technical field of vehicle detection, and in particular to an OBD module disconnection detection method, an OBD vehicle-mounted monitoring terminal, and an OBD monitoring system.

Background technique

Motor vehicle emissions are one of the main sources of environmental pollution. In particular, nitrogen oxide and particulate matter emissions from diesel vehicles account for 68.3% and 77.8% of total vehicle emissions, respectively. In order to strengthen the emission control of heavy diesel vehicles, the national environmental protection department requires remote monitoring of motor vehicle emissions. On-Board Diagnostics (OBD) is mandatory to install on each motor vehicle, through which the system regularly manages the server in the background Report emission monitoring data, provide early warnings and warnings for vehicles that do not meet emission requirements, and notify vehicle owners for maintenance. In order to prevent the terminal from not being able to report data effectively, the installed OBD device is strictly prohibited to be unplugged maliciously.

At present, the pin of the OBD connector is generally a normal power supply, and the vehicle battery directly supplies power to this pin. Therefore, it is usually detected whether the OBD connector has voltage to determine whether the OBD device is unplugged. If the OBD connector has no voltage, the OBD device is considered to be unplugged, and if the OBD connector has voltage, it is considered that the OBD device is not unplugged. .

In the process of implementing the embodiments of the present invention, the inventor found that the related technology has at least the following problems: if the communication line is disconnected without disconnecting the power cord, this situation may also be a malicious unplugging situation, but it will be considered by the algorithm as not malicious unplugging. . Therefore, the prior art has a problem of low accuracy when detecting whether the OBD device is maliciously pulled out.

Summary of the invention

The embodiments of the present invention aim to provide an OBD module disconnection detection method, an OBD vehicle monitoring terminal, and an OBD monitoring system, which are used to improve the accuracy of detecting whether the OBD module is maliciously pulled out.

To solve the above technical problems, the embodiments of the present invention provide the following technical solutions:

In the first aspect, the embodiment of the present invention provides an OBD module disconnection detection method, which is applied to an OBD vehicle monitoring terminal, the OBD vehicle monitoring terminal includes an MCU and an OBD module, and the OBD module is connected to the OBD interface on the vehicle , So that the OBD module communicates with an electronic control unit on the vehicle, the method includes:

The MCU detects whether the communication between the OBD module and the electronic control unit on the vehicle is abnormal;

If yes, the MCU determines whether the vehicle supports the high-speed CAN communication protocol;

If the vehicle supports the high-speed CAN communication protocol, the MCU detects whether the CAN loop between the OBD module and the electronic control unit on the vehicle is turned on;

If not, the MCU sends a disconnection warning of the OBD module to the background management server to warn that the OBD module is disconnected from the electronic control unit of the vehicle.

Optionally, the MCU detecting whether the CAN loop between the OBD module and the electronic control unit on the vehicle is turned on, including:

The MCU outputs a high-level signal to control the first data line terminal in the CAN loop to input a first voltage;

The MCU detects whether the second voltage of the second data line terminal in the CAN loop matches the first voltage;

If it does not match, the CAN loop is not conducting.

Optionally, the first voltage is a randomly selected voltage in a preset voltage set.

Optionally, the matching relationship between any one voltage in the preset voltage set and the voltage of the second data line terminal is determined when the OBD vehicle monitoring terminal is connected to the vehicle for the first time, and the OBD is pre-stored In the vehicle monitoring terminal.

Optionally, whether the vehicle supports the high-speed CAN communication protocol is detected when the OBD vehicle-mounted monitoring terminal is installed, and the detection result is pre-stored in the OBD vehicle-mounted monitoring terminal.

Optionally, when an abnormal communication between the OBD module and the electronic control unit on the vehicle is detected, the method further includes:

Wake up the OBD vehicle-mounted monitoring terminal in the dormant state, and activate the configuration of the OBD vehicle-mounted monitoring terminal.

Optionally, if the vehicle does not support the high-speed CAN communication protocol, the method further includes:

The MCU detects whether the OBD module supports normal power supply;

If the normal power supply is supported and the power is turned on, or the normal power supply is not supported, the vehicle will be detected according to the position information of the vehicle and the time when the OBD module and the electronic control unit on the vehicle have abnormal communication. The connection status of the OBD module;

If the normal power supply is supported and the power supply is disconnected, the MCU sends a disconnection warning of the OBD module to the background management server to warn that the OBD module is disconnected from the electronic control unit of the vehicle.

Optionally, whether the OBD module supports the normal power supply is configured when the OBD vehicle-mounted monitoring terminal is installed, and the configuration result is pre-stored in the OBD vehicle-mounted monitoring terminal.

Optionally, the detecting the connection state of the OBD module according to the position change information of the vehicle and the time when the OBD module and the electronic control unit on the vehicle are abnormal in communication, includes:

Acquiring location information of the vehicle;

Determine whether the position of the vehicle has changed when the OBD module and the electronic control unit have a communication abnormality;

If the position of the vehicle has not changed, it is detected whether the time of abnormal communication between the OBD module and the electronic control unit is greater than or equal to the preset time, and if so, the MCU sends the OBD module to the background management server Disconnect early warning, and execute the OBD module disconnection detection and monitoring program again;

If the position of the vehicle has changed, the MCU sends a disconnection warning of the OBD module to the background management server to warn that the OBD module is disconnected from the electronic control unit of the vehicle.

In a second aspect, an embodiment of the present invention also provides an OBD vehicle-mounted monitoring terminal, including: an MCU, an OBD module, and a communication module. The OBD module is connected to the OBD interface on the vehicle so that the OBD module and the Communication with the electronic control unit on the vehicle;

The MCU is used for:

Detecting whether the communication between the OBD module and the electronic control unit on the vehicle is abnormal;

If yes, determine whether the vehicle supports the high-speed CAN communication protocol;

If the vehicle supports the high-speed CAN communication protocol, detecting whether the CAN loop between the OBD module and the electronic control unit on the vehicle is turned on;

If not, send a disconnection warning of the OBD module to the background management server through the communication module to warn that the OBD module is disconnected from the electronic control unit of the vehicle.

Optionally, the OBD module includes an OBD connector and an OBD chip, the OBD chip is electrically connected to the OBD connector and the MCU, and the OBD connector is connected to an OBD interface on the vehicle.

Optionally, when the vehicle supports the high-speed CAN communication protocol, the OBD module and the OBD interface on the vehicle are connected by a high-speed CAN bus, and the high-speed CAN bus forms a CAN loop;

The MCU is used for:

Output a high-level signal to control the first data line terminal in the CAN loop to input a first voltage;

It is detected whether the second voltage of the second data line terminal in the CAN loop matches the first voltage, and if it does not match, the CAN loop does not conduct.

Optionally, when an abnormal communication between the OBD module and the electronic control unit on the vehicle is detected, the MCU is further configured to:

Optionally, the OBD vehicle-mounted monitoring terminal further includes a positioning module electrically connected to the MCU;

The positioning module is used to detect the position information of the vehicle;

If the vehicle does not support the high-speed CAN communication protocol, the MCU is also used to:

Detecting whether the OBD module supports normal power supply;

If the normal power supply is supported and the power supply is disconnected, a disconnection warning of the OBD module is sent to the background management server to warn that the OBD module is disconnected from the electronic control unit of the vehicle.

Optionally, the OBD vehicle-mounted monitoring terminal further includes an alarm module electrically connected to the MCU;

The alarm module is used to send an alarm when the OBD module is disconnected.

Optionally, the OBD vehicle monitoring terminal further includes a power management module, a battery, and a charger, the power management module is respectively connected to the OBD module, the MCU, the battery, and the charger, and the battery is respectively connected to the OBD module, the MCU, the battery and the charger. Connect the charger and the MCU.

In the third aspect, the embodiments of the present invention also provide an OBD monitoring system, which is applied to a car, the car is provided with an OBD interface, and the system includes: the above-mentioned OBD vehicle monitoring terminal, a network, and a background management server ；

The OBD vehicle-mounted monitoring terminal communicates with the car through the OBD interface, and communicates with the background management server through the network;

The OBD vehicle-mounted monitoring terminal is used to detect whether the CAN circuit between the OBD vehicle-mounted monitoring terminal and the electronic control unit of the car is conductive when the car supports the high-speed CAN communication protocol. The background management server sends a disconnection warning of the OBD vehicle-mounted monitoring terminal;

The background management server is configured to receive the disconnection warning and respond to the disconnection warning.

The beneficial effect of the present invention is that compared with the prior art, the embodiments of the present invention provide an OBD module disconnection detection method, an OBD vehicle-mounted monitoring terminal, and an OBD monitoring system. By detecting whether the communication between the OBD module and the electronic control unit on the vehicle is abnormal; if it is abnormal, determine whether the vehicle supports the high-speed CAN communication protocol; if the vehicle supports the high-speed CAN communication protocol, detect the communication between the OBD module and the electronic control unit on the vehicle If the CAN circuit is not turned on, the OBD vehicle monitoring terminal sends a disconnection warning of the OBD module to the background management server to warn that the communication between the OBD module and the electronic control unit of the vehicle is disconnected. The OBD module disconnection detection method, the OBD vehicle monitoring terminal and the OBD monitoring system provided by the embodiments of the present invention can more accurately detect whether the communication between the OBD module and the electronic control unit of the vehicle is disconnected, and can prevent non-malicious pulling out of the OBD The situation of the vehicle monitoring terminal is incorrectly identified as a malicious pullout situation, which improves the accuracy of OBD module disconnection detection.

Description of the drawings

One or more embodiments are exemplified by the pictures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. The elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the attached drawings do not constitute a scale limitation.

Figure 1 is a schematic structural diagram of an OBD monitoring system provided by an embodiment of the present invention;

Figure 2 is a schematic structural diagram of an OBD vehicle-mounted monitoring terminal provided by an embodiment of the present invention;

Figure 3a is a communication network topology diagram corresponding to one of the high-speed CAN protocols provided by an embodiment of the present invention;

Figure 3b is a communication network topology diagram corresponding to another high-speed CAN protocol provided by an embodiment of the present invention;

4 is a flowchart of one of the OBD module disconnection detection methods provided by the embodiment of the present invention;

Fig. 5 is a flowchart of another OBD module disconnection detection method provided by an embodiment of the present invention.

Detailed ways

In order to facilitate the understanding of the application, the application will be described in more detail below with reference to the drawings and specific implementations. It should be noted that when an element is expressed as being "connected" to another element, it may be directly connected to the other element, or one or more intermediate elements may exist in between. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance.

Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the technical field of the present invention. The terminology used in the specification of the present invention is only for the purpose of describing specific embodiments, and is not used to limit the present invention. The term "and/or" used in this specification includes any and all combinations of one or more related listed items.

In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

Please refer to FIG. 1. FIG. 1 is a schematic structural diagram of an OBD monitoring system provided by an embodiment of the present invention. As shown in FIG. 1, the system 100 includes an OBD vehicle monitoring terminal 10, a network 20 and a background management server 30. The system can be applied to a car. The car is equipped with an OBD interface, wherein the OBD vehicle-mounted monitoring terminal 10 is connected to the vehicle through the OBD interface, and is used to monitor the emission data of the vehicle and the OBD vehicle-mounted monitoring terminal 10, and also send the emission data and the unplug event to the background management server 30 through the network 20. The background management server 30 is used for correspondingly controlling the emission of the automobile according to the emission data, giving early warnings and warnings to vehicles that do not meet the emission requirements, and notifying the owners of maintenance and rectification. In addition, the background management server 30 is also used to monitor the pull-out event of the OBD vehicle monitoring terminal 10, and grasp the connection between the OBD vehicle monitoring terminal 10 and the car in time. For example, the OBD vehicle monitoring terminal 10 is used to detect whether the CAN circuit between the OBD vehicle monitoring terminal 10 and the electronic control unit of the vehicle is conductive when the vehicle supports the high-speed CAN communication protocol. The background management server 30 sends the disconnection warning of the OBD vehicle monitoring terminal to the background management server 30; the background management server 30 is configured to receive the disconnection warning and respond to the disconnection warning.

Wherein, the network 20 may be a mobile network, which supports TCP/IP protocol and the like.

In some embodiments, the system 100 may further include a satellite, and the OBD vehicle monitoring terminal 10 may communicate with the satellite to locate the car. The location information of the car can be uploaded to the background management server 30 by the OBD vehicle monitoring terminal 10 via the network 20.

It should be noted that although FIG. 1 only shows one OBD vehicle-mounted monitoring terminal 10, it can be understood that multiple OBD vehicle-mounted monitoring terminals 10 may also be included, and each OBD vehicle-mounted monitoring terminal 10 corresponds to a car. The type of OBD vehicle monitoring terminal 10 is not limited, and each OBD vehicle monitoring terminal 10 can be connected to the background management server 30 through the network 20, so that the background management server 30 can simultaneously monitor the OBD vehicle monitoring terminal 10 on multiple vehicles.

The embodiment of the present invention provides an OBD monitoring system, which monitors the pull-out event of the OBD vehicle-mounted monitoring terminal 10, and reports the monitoring data to the background management server 30. The system improves the detection of the pull-out event of the OBD vehicle-mounted monitoring terminal 10 Accuracy. For technical details that are not described in detail in this embodiment, please refer to the following device embodiment.

Please refer to FIG. 2, which is a schematic structural diagram of one of the OBD vehicle-mounted monitoring terminals according to an embodiment of the present invention. The OBD vehicle monitoring terminal 10 includes: an OBD module 101, an MCU 102, and a communication module 103, and the MCU 102 is electrically connected to the OBD module 101 and the communication module 103, respectively. The OBD module 101 includes an OBD connector 1011 and an OBD chip 1012, and the OBD chip 1012 is electrically connected to the OBD connector 1011 and the MCU, respectively.

The OBD module 101 is connected to an OBD interface on the automobile, so that the OBD module 101 communicates with an electronic control unit (ECU) of the automobile. Specifically, the OBD module 101 is connected to the OBD interface of the car through the OBD connector 1011, and a communication connection between the car and the OBD vehicle monitoring terminal 10 is established through the OBD chip.

Wherein, the OBD connector 1011 usually includes 16 pins. The meaning of the 16 pins can refer to the prior art. For example, Pin4 represents the chassis ground, Pin5 represents the signal ground, and Pin16 represents the normal power supply. Above, Pin16 can be directly connected to the battery. Other pins are either communication lines or reserved pins. For example, Pin1, Pin3, Pin8, Pin9, Pin11, Pin12 and Pin13 are not allocated and can be defined by the vehicle manufacturer. Pin2, Pin6, Pin7, Pin10, Pin14 and Pin15 can be used for diagnostic communication, such as high-speed CAN communication protocol commonly used Pin6 and Pin14 communication, KWP2000 line protocol commonly used Pin7 and Pin15 communication. Optionally, the OBD connector 101 may also be a round hole connector containing 9 pins, and the corresponding meaning of each pin is adjusted according to actual applications.

The OBD chip 1012 supports CAN, PWP2000, SAE J1850 (PWM), SAE J1850 (VPW), ISO 15765-4, ISO9141-2, ISO 14230-4 and other communication protocols. The OBD chip 1012 can automatically scan and identify the communication protocol, select and connect different communication lines, and perform signal conversion. For example, the OBD chip 1012 can perform data communication with the MCU 102 through a communication protocol such as a serial port, SPI, or CAN.

The MCU 102 serves as the control core of the OBD on-board monitoring terminal 10, and is used for data communication with other modules based on a communication protocol, and processing according to the acquired data to perform corresponding functions. The MCU 102 may be provided with a USB interface, which is used to connect a USB device. The MCU 102 can also be provided with a serial peripheral interface SPI, which can be used to connect to other chips, such as encryption chips.

The communication module 103 may perform data communication with the MCU 102 based on a Universal Asynchronous Receiver/Transmitter (UART). The communication module 103 supports 2G, 3G, 4G, and 5G mobile network data communication, and supports assisted global positioning system (Assisted Global Positioning System, AGPS) assisted positioning.

Wherein, the OBD on-board monitoring terminal 10 may be a type II on-board diagnostic system (On-Board Diagnostic II, OBD II), and the type of the OBD connector 1011 is OBD II.

The OBD vehicle-mounted monitoring terminal 10 is mainly used to monitor vehicle emissions, and regularly report emission monitoring data to the back-end management server 30, so that the back-end management server 30 can give early warnings and warnings to vehicles that do not meet the requirements, and notify the owner of the vehicle. Carry out repair processing. Therefore, it is generally prohibited that the OBD vehicle monitoring terminal 10 is maliciously pulled out of the car. In order to prevent the OBD vehicle-mounted monitoring terminal 10 from not being able to effectively report monitoring data, it is of great significance to detect the pull-out event.

The OBD vehicle-mounted monitoring terminal 10 is plugged into the OBD interface of the car through the OBD connector 1011 to connect to the car. Therefore, detecting the unplugging event of the OBD vehicle-mounted monitoring terminal 10 is to detect whether the OBD connector 1011 is maliciously unplugged. In this embodiment, in order to improve the accuracy of unplugging detection, factors such as the communication link status of the OBD vehicle monitoring terminal 10, the closedness of the detection communication loop, the power status of the OBD connector 1011, and the vehicle operating status are comprehensively analyzed.

Specifically, the MCU 102 is used to detect whether the communication between the OBD module 101 and the electronic control unit on the car is abnormal; if it is abnormal, determine whether the car supports the high-speed CAN communication protocol; if the car supports the high-speed CAN communication protocol , Detect whether the CAN circuit between the OBD module 101 and the electronic control unit of the automobile is conductive; if not, send a disconnection warning of the OBD module to the background management server 30 to warn the The communication between the OBD module and the electronic control unit of the car is disconnected.

Wherein, when the OBD connector 1011 is unplugged or the vehicle power is turned off, the communication link between the OBD vehicle monitoring terminal 10 and the vehicle will be disconnected, for example, the communication between the OBD vehicle monitoring terminal 10 and the ECU is terminated. Therefore, data signals can be sent to the OBD vehicle monitoring terminal 10 through the ECU. If the ECU cannot receive the feedback signal returned by the OBD vehicle monitoring terminal 10, it can be determined that the OBD module 101 is connected to the vehicle. The communication of the electronic control unit is abnormal. Of course, other methods can also be used to detect whether the communication between the OBD module 101 and the electronic control unit on the automobile is abnormal.

Wherein, whether the vehicle supports the high-speed CAN communication protocol may be detected when the OBD vehicle-mounted monitoring terminal 10 is installed, and the detection result is pre-stored in the OBD vehicle-mounted monitoring terminal 10.

Usually most cars use the high-speed CAN communication protocol to communicate with the car's ECU. The topological structure of the communication network can refer to Figure 3a and Figure 3b. In Figure 3a, the high-speed CAN bus is a loopback loop. All devices can be accessed through CAN_H and CAN_L. The loopback loop supports a multi-host structure. All devices connected to the CAN bus can send information by broadcasting. The incoming device can choose the information it receives according to its needs. The OBD vehicle monitoring terminal 10 can be connected to the high-speed CAN bus through CAN_H and CAN_L, and the OBD vehicle monitoring terminal 10 can be connected to the high-speed CAN bus through pins Pin6 and Pin14 on the OBD connector 1011. The ECU of the car can also be connected to the high-speed CAN bus through CAN_H and CAN_L, and the ECU of the car can be connected to the high-speed CAN bus through pins Pin6 and Pin14 of the OBD interface connected to it. Wherein, the resistance in FIG. 3a may specifically be 120 ohms, etc., when the resistance is 120 ohms, the CAN loop can be well connected, and poor contact at a certain connection of the conductive loop can be avoided. The CAN_H is the high-level end of the high-speed CAN bus, and the CAN_L is the low-level end of the high-speed CAN bus.

As shown in Figure 3a, because the high-speed CAN network topology is a closed loop, a voltage is added to the CAN_H terminal of the OBD device, and another corresponding voltage can be detected at the CAN_L terminal of the OBD device. If the OBD connector 1011 is unplugged, the circuit of CAN_H and CAN_L is disconnected, and the voltage applied to the CAN_H terminal cannot be fed back to the CAN_L terminal.

It is possible to detect whether the car supports the high-speed CAN communication protocol according to the above-mentioned principle, and for the car that supports high-speed CAN communication, it can also detect whether the OBD connector 1011 is unplugged according to the above-mentioned principle.

The MCU 102 is used to detect whether the CAN loop between the OBD module 101 and the electronic control unit on the automobile is turned on, including: the MCU 102 outputs a high-level signal to control the CAN loop A first voltage is input to the first data line terminal; the MCU 102 detects whether the second voltage at the second data line terminal in the CAN loop matches the first voltage; if it does not match, the CAN loop does not match Conduction.

The high-level signal output by the MCU 102 is used to control the power supply to input the first voltage to the first data line end of the CAN loop. The first voltage is a randomly selected voltage in a preset voltage set. The matching relationship between any one of the preset voltage sets and the voltage of the second data line terminal is determined when the OBD vehicle-mounted monitoring terminal is connected to the vehicle for the first time, and is pre-stored in the OBD vehicle-mounted monitoring terminal . For example, when the OBD vehicle monitoring terminal is installed in a vehicle for the first time, or in other situations, the MCU 102 controls the power supply to input voltages of 5V, 4.2V, 3.7V, 3.3V, and 3V at CAN_H in Figure 3a. 1011 is inserted into the car to detect the voltages respectively output at CAN_L, each output voltage corresponds to the above-mentioned input voltage one-to-one, and the voltage input by CAN_H and the voltage output by CAN_L are correspondingly saved in the database.

The first data line end may be CAN_H, then the second data line end is CAN_L; the first data line end may also be CAN_L, then the second data line end is CAN_H.

For example, as shown in Figure 3b, by default, MCU 102 controls GPIO to output low-level signals. At this time, S0 is connected to CAN_H of OBD II (that is, CAN_H is connected to CAN_H1), and S1 is connected to CAN_L of OBD II (that is, CAN_L). Connect CAN_L1), at this time the signal is normally transmitted between OBD II and CAN loop. When it is necessary to detect whether the CAN loop between the OBD module 101 and the electronic control unit on the car is turned on, the MCU 102 controls the GPIO to output a high-level signal, and the control power supply VCC provides an input voltage (such as 3V~ 5V), at this time S0 is connected to VCC (that is, VCC is connected to CAN_H1), and S1 is connected to ADC (that is, ADC is connected to CAN_L1), so the MCU and CAN loop form a new loop, because the input voltage is added to the VCC terminal connected to S0 Therefore, the ADC can detect the voltage connected to S1 to determine whether the CAN circuit is normal. If the voltage connected to S1 matches the voltage added to S0, the CAN circuit is turned on, otherwise it is not turned on. Among them, the S0 and S1 are routing switches, and the connection between S0 and S1 can be controlled by controlling the level signal output by GPIO to control S0 to choose one between CAN_H and VCC, and control S1 to be between CAN_L and ADC Choose one of the two to control CAN_H1 and CAN_L1 to connect to the corresponding network.

The embodiment of the present invention detects whether the OBD connector 1011 is unplugged by detecting the connection state of the CAN loop when the car supports the high-speed CAN communication protocol, instead of simply thinking that the unplugging event is triggered when the communication link is disconnected. Therefore, the accuracy of disconnection detection of the OBD module 101 is improved.

In some embodiments, referring to FIG. 2 as well, the OBD II vehicle monitoring terminal 10 further includes a power management module 104, a battery 105, a charger 106, and a fuel gauge 107. The power management module 104 is connected to the OBD connector. 1011. The OBD chip 1012, the MCU 102, the battery 105, and the charger 106, and the OBD connector 1011 is connected to the battery 105 through the charger 106. The OBD vehicle-mounted monitoring terminal 10 can be powered by the Pin 16 of the OBD connector 101, or can be powered by the battery 105, and the Pin 16 can also charge the battery 105. The fuel gauge 107 is used to count the power of the battery 105 and report the statistics result to the MCU 102.

In some embodiments, referring to FIG. 2 as well, the OBD vehicle monitoring terminal 10 further includes an alarm module 108, and the alarm module 108 is electrically connected to the MCU 102 through a GPIO interface. Wherein, if it is detected that the CAN loop is disconnected, an OBD connector 1011 disconnection alarm signal can be issued. The alarm signal is used to prompt the OBD vehicle-mounted monitoring terminal 10 to be maliciously pulled out. The OBD chip 1012 may send the alarm signal to the MCU 102, and the MCU 102 sends the alarm signal to the background management server 30 through the communication module 103. The MCU 102 may also control the alarm module 108 to perform an alarm. The alarm module 108 may be an indicator light, a horn, etc., and may emit a preset sound and/or light signal when an alarm occurs.

In some embodiments, some cars do not support the high-speed CAN protocol, and the communication link is also disconnected. At this time, whether the OBD connector 1011 can be detected according to factors such as the power state of the OBD connector 1011 and the motion state of the car Was unplugged. Specifically, referring to FIG. 2 as well, the OBD vehicle-mounted monitoring terminal 10 further includes a positioning module 109, and the positioning module 109 is electrically connected to the MCU 102. The positioning module 109 is used to detect real-time position information of the car. The positioning module 109 can receive signals from GPS (Global Positioning System), BD (Beidou Satellite Positioning System), GLONASS (Galileo Satellite Positioning System), and Galileo (Galileo Satellite Positioning System).

If the vehicle does not support the high-speed CAN communication protocol, the MCU 102 is also used to detect whether the OBD module 101 supports the normal power supply; if it supports the normal power supply and is in the power-on state, or does not support the normal power supply, then Detect the connection state of the OBD module 101 according to the position information of the vehicle and the time when the OBD module 101 and the electronic control unit on the vehicle have a communication abnormality; if the normal power supply is supported and the power supply is disconnected , A disconnection warning of the OBD module 101 is sent 30 to the background management server to warn that the OBD module 101 is disconnected from the electronic control unit of the vehicle.

Among them, the 16 pins of the OBD connector 1011, that is, Pin16 is usually a normal power supply, and the battery of the car can directly supply power to the Pin16.

Wherein, whether the OBD module 101 supports the normal power supply is configured when the OBD vehicle-mounted monitoring terminal 10 is installed, and the configuration result is pre-stored in the OBD vehicle-mounted monitoring terminal 10.

Wherein, the detecting the connection state of the OBD module 101 according to the position change information of the vehicle and the time when the OBD module 101 and the electronic control unit on the vehicle are abnormally communicated includes: acquiring the Location information of the vehicle; determine whether the location of the vehicle has changed when the OBD module 101 and the electronic control unit communicate abnormally; if the location of the vehicle has not changed, detect that the OBD module 101 and Whether the communication abnormality of the electronic control unit is greater than or equal to the preset time, if yes, the MCU 102 sends the disconnection warning of the OBD module 101 to the background management server, and executes the OBD module 101 disconnection detection and monitoring again Program; if the location of the vehicle has changed, the MCU 102 sends a disconnection warning of the OBD module 101 to the background management server to warn the OBD module 101 to communicate with the electronic control unit of the vehicle disconnect.

It is understandable that if the car is parked and the engine is not working, the car has no exhaust emissions at this time. This state does not need to monitor its emissions, and if the car is in motion and the engine continues to work, then the OBD vehicle monitoring terminal 10 must be started. In this embodiment, the OBD vehicle-mounted monitoring terminal 10 has a satellite positioning function, and can detect the real-time position information of the car according to the positioning module 109 described above. If the car is in motion and the communication link is disconnected, the OBD connector 1011 is definitely in the unplugged state; if the car is stationary and the communication link is disconnected, although it cannot be concluded that the OBD connector 1011 must be in the unplugged state. The status does not conform to the regular business rules of motor vehicles, therefore, at this time, it is necessary to give an early warning to the background.

Wherein, the preset time can be self-defined setting, such as 24 hours, 12 hours, etc. The disconnection warning is used to remind the background management server that a disconnection event may currently occur. After the early warning operation is performed, the detection method of the foregoing embodiment can be repeated continuously to perform disconnection detection on the OBD module 101. If the position of the car has not changed, and the time for which the position has not changed when the communication link is disconnected is less than the preset time, the OBD module 101 disconnection detection monitoring program can be executed again. Wherein, the disconnection warning is issued to the background management server 30 when the time when the position of the car has not changed is greater than or equal to the preset time, and the OBD module 101 and the electronic control unit have been communicating abnormally during this time. The situation does not conform to the regular business laws of motor vehicles. In order to avoid this situation that may be caused by the unplugging event, it is necessary to give an early warning to the background management server 30 to improve the safety of the equipment.

In some embodiments, when an abnormal communication between the OBD module and the electronic control unit on the vehicle is detected, the MCU 102 is also used to wake up the OBD vehicle-mounted monitoring terminal 10 in a sleep state , And activate the configuration of the OBD vehicle monitoring terminal 10.

It can be understood that, in order to reduce energy consumption, the OBD vehicle-mounted monitoring terminal 10 can be put into a sleep state when the car engine is turned off. Because the OBD vehicle-mounted monitoring terminal 10 usually needs to resume communication with the ECU within 60 seconds of starting the engine, in order to improve the detection accuracy, the OBD vehicle-mounted monitoring terminal 10 must be activated within 60 seconds at most when the engine is started.

Wherein, during the sleep period of the OBD vehicle monitoring terminal 10, the communication module 103 and the positioning module 109 do not need to work and enter a low power consumption mode. After the OBD connector 1011 is unplugged, the MCU 102 can also detect the unplugging status and report the server alarm information. When the OBD connector 1011 is unplugged, the battery 105 supplies power to the OBD vehicle monitoring terminal 10.

Wherein, activating the OBD vehicle monitoring terminal 10 is activation configuration information, and the configuration information includes OBD communication protocol, whether to support high-speed CAN communication protocol, server communication address, OBD II Pin16 constant power supply support and other information. After the configuration is completed, the configuration is activated and the monitoring takes effect. If the OBD vehicle-mounted monitoring terminal 10 is not activated, the disconnection detection and monitoring program of the OBD module 101 is not run. Therefore, the vehicle that has not activated the OBD vehicle-mounted monitoring terminal 10 will not be affected by the operating state.

Based on the foregoing embodiment, the disconnection detection process of the OBD module 101 is described below by using an example, and the model of the OBD device is OBD II.

For example, as shown in Figure 4, first check whether the communication of the OBD II device is normal. If it is normal, it means that the OBD II device is connected normally; if the communication is abnormal, wake up the sleeping OBD II vehicle monitoring terminal and activate the configuration. At the same time, check again whether the communication is back to normal. If it is still abnormal, according to whether the car supports the high-speed CAN protocol, whether the car supports OBD II Pin16 normal power supply, the connection status of the CAN loop between the OBD II device and the car, and the car’s Information such as the location change performs detailed detection of the disconnection of the OBD II device. For the detailed process, refer to the foregoing embodiment.

Among them, when the car engine is turned off, the OBD II device is in the dormant state. When it is necessary to detect whether the OBD II device has an unplug event, the configuration of the OBD II device needs to be activated first, because the OBD II device needs to be restored within 60 seconds of the engine start In order to improve the detection accuracy of the communication with the car, the OBD II device must be activated within 60 seconds at most when the car engine is started.

Among them, when detecting the connection status of the CAN loop, a voltage of 3 to 5V is applied to CAN_H, the voltage value is preset, and there is a corresponding output voltage at CAN_L. In practical applications, other voltages can also be set according to the CAN loop.

Among them, if the time that the car position has not changed is greater than or equal to 24 hours, and the OBD II device and the car have been communicating abnormally during this time, this situation does not conform to the regular business rules of motor vehicles, in order to avoid the possibility of unplugging incidents causing this In this case, it is necessary to give an early warning to the background management server to improve equipment security.

The embodiment of the present invention provides an OBD vehicle-mounted monitoring terminal. By detecting whether the communication between the OBD module and the electronic control unit on the vehicle is abnormal; if it is abnormal, determine whether the vehicle supports the high-speed CAN communication protocol; if the vehicle supports the high-speed CAN communication protocol, detect the communication between the OBD module and the electronic control unit on the vehicle If the CAN circuit is not turned on, the OBD vehicle monitoring terminal sends a disconnection warning of the OBD module to the background management server to warn that the communication between the OBD module and the electronic control unit of the vehicle is disconnected. In summary, the terminal improves the accuracy of OBD module disconnection detection and reduces the probability of false alarms when the OBD module is unplugged. Secondly, the OBD vehicle monitoring terminal can support multiple communication protocols and achieve full OBD functions; again, A low-power design is added to reduce the system power consumption; finally, the terminal is suitable for all kinds of cars, including all road mobile vehicles and most non-road construction machinery vehicles, with strong versatility.

Please refer to FIG. 5, which is a flowchart of a method for detecting disconnection of an OBD module according to an embodiment of the present invention. The OBD module disconnection detection method can be applied to the OBD vehicle-mounted monitoring terminal described in any of the above embodiments. The OBD vehicle-mounted monitoring terminal includes an MCU and an OBD module, and the OBD module is connected to the OBD interface on the vehicle to enable The OBD module communicates with an electronic control unit on the vehicle, and the method includes:

S201: The MCU detects whether the communication between the OBD module and the electronic control unit on the vehicle is abnormal.

If yes, execute the following step S202. If not, the OBD module is in a normal connection state.

S202: The MCU determines whether the vehicle supports the high-speed CAN communication protocol.

If yes, execute the following step S203.

S203: The MCU detects whether the CAN loop between the OBD module and the electronic control unit on the vehicle is turned on.

If not, execute the following step S204; if yes, the OBD module is in a normal connection state.

S204: The MCU sends a disconnection warning of the OBD module to the background management server to warn that the OBD module is disconnected from the electronic control unit of the vehicle.

Wherein, the MCU detecting whether the CAN loop between the OBD module and the electronic control unit on the vehicle is conducted, including:

If it does not match, the CAN loop is not conducting.

Wherein, the first voltage is a randomly selected voltage in a preset voltage set.

Wherein, the matching relationship between any one voltage in the preset voltage set and the voltage of the second data line terminal is determined when the OBD on-board monitoring terminal is connected to the vehicle for the first time, and is pre-stored in the OBD on-board monitoring In the terminal.

Wherein, whether the vehicle supports the high-speed CAN communication protocol is detected when the OBD vehicle-mounted monitoring terminal is installed, and the detection result is pre-stored in the OBD vehicle-mounted monitoring terminal.

Wherein, when an abnormal communication between the OBD module and the electronic control unit on the vehicle is detected, the method further includes:

In some embodiments, if the vehicle does not support the high-speed CAN communication protocol, the method further includes:

The MCU detects whether the OBD module supports normal power supply;

Wherein, whether the OBD module supports the normal power supply is configured when the OBD vehicle-mounted monitoring terminal is installed, and the configuration result is pre-stored in the OBD vehicle-mounted monitoring terminal.

Wherein, the detecting the connection state of the OBD module according to the position change information of the vehicle and the time when the OBD module and the electronic control unit on the vehicle are abnormal in communication, includes:

Acquiring location information of the vehicle;

It should be noted that the foregoing method embodiment and the device embodiment of the present invention are based on the same concept, and the specific content can be referred to the description in the device embodiment of the present invention, which will not be repeated here.

The embodiment of the present invention provides a method for detecting disconnection of an OBD module. This method detects whether the communication between the OBD module and the electronic control unit on the vehicle is abnormal; if it is abnormal, it is determined whether the vehicle supports the high-speed CAN communication protocol; if the vehicle supports the high-speed CAN communication protocol, the OBD module and the electronic control unit on the vehicle are detected Whether the CAN circuit between the two is turned on; if the CAN circuit is not turned on, the OBD vehicle monitoring terminal sends a disconnection warning of the OBD module to the background management server to warn that the communication between the OBD module and the electronic control unit of the vehicle is broken open. In summary, this method improves the accuracy of OBD module disconnection detection and reduces the probability of false alarms of OBD module unplugging events; secondly, this method reduces system power consumption; finally, this method is suitable for all kinds of cars, including all roads Mobile vehicles and most non-road construction machinery vehicles have strong versatility.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, not to limit them; under the idea of the present invention, the technical features of the above embodiments or different embodiments can also be combined. The steps can be implemented in any order, and there are many other variations of the different aspects of the present invention as described above. For the sake of brevity, they are not provided in the details; although the present invention has been described in detail with reference to the foregoing embodiments, it is common in the art The skilled person should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or equivalently replace some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the implementations of the present invention. Examples of the scope of technical solutions.

Claims

An OBD module disconnection detection method is applied to an OBD vehicle-mounted monitoring terminal. The OBD vehicle-mounted monitoring terminal includes an MCU and an OBD module. The OBD module is connected to an OBD interface on a vehicle so that the OBD module is connected to the vehicle. The electronic control unit communication on the computer is characterized in that it includes:

The MCU detects whether the communication between the OBD module and the electronic control unit on the vehicle is abnormal;

If yes, the MCU determines whether the vehicle supports the high-speed CAN communication protocol;

If the vehicle supports the high-speed CAN communication protocol, the MCU detects whether the CAN loop between the OBD module and the electronic control unit on the vehicle is turned on;

If not, the MCU sends a disconnection warning of the OBD module to the background management server to warn that the OBD module is disconnected from the electronic control unit of the vehicle.
The method according to claim 1, wherein the MCU detecting whether the CAN loop between the OBD module and the electronic control unit on the vehicle is turned on, comprising:

The MCU outputs a high-level signal to control the first data line terminal in the CAN loop to input a first voltage;

The MCU detects whether the second voltage of the second data line terminal in the CAN loop matches the first voltage;

If it does not match, the CAN loop is not conducting.
The method according to claim 2, wherein the first voltage is a randomly selected voltage in a preset voltage set.
The method according to claim 3, wherein the matching relationship between any one voltage in the preset voltage set and the voltage at the second data line terminal is when the OBD vehicle-mounted monitoring terminal is connected to the vehicle for the first time Determined and pre-stored in the OBD vehicle monitoring terminal.
The method according to claim 1, wherein whether the vehicle supports the high-speed CAN communication protocol is detected when the OBD vehicle-mounted monitoring terminal is installed, and the detection result is pre-stored in the OBD vehicle-mounted monitoring terminal.
The method according to claim 1, wherein when an abnormal communication between the OBD module and the electronic control unit on the vehicle is detected, the method further comprises:

Wake up the OBD vehicle-mounted monitoring terminal in the dormant state, and activate the configuration of the OBD vehicle-mounted monitoring terminal.
The method according to any one of claims 1 to 6, wherein if the vehicle does not support the high-speed CAN communication protocol, the method further comprises:

The MCU detects whether the OBD module supports normal power supply;

If the normal power supply is supported and the power is turned on, or the normal power supply is not supported, the vehicle will be detected according to the position information of the vehicle and the time when the OBD module and the electronic control unit on the vehicle have abnormal communication. The connection status of the OBD module;

If the normal power supply is supported and the power supply is disconnected, the MCU sends a disconnection warning of the OBD module to the background management server to warn that the OBD module is disconnected from the electronic control unit of the vehicle.
8. The method according to claim 7, wherein whether the OBD module supports normal power is configured when the OBD vehicle-mounted monitoring terminal is installed, and the configuration result is pre-stored in the OBD vehicle-mounted monitoring terminal.
8. The method according to claim 7, wherein the OBD module is detected according to the position change information of the vehicle and the time when the OBD module and the electronic control unit on the vehicle are abnormal in communication The connection status includes:

Acquiring location information of the vehicle;

Determine whether the position of the vehicle has changed when the OBD module and the electronic control unit have a communication abnormality;

If the position of the vehicle has not changed, it is detected whether the time of abnormal communication between the OBD module and the electronic control unit is greater than or equal to the preset time, and if so, the MCU sends the OBD module to the background management server Disconnect early warning, and execute the OBD module disconnection detection and monitoring program again;

If the position of the vehicle has changed, the MCU sends a disconnection warning of the OBD module to the background management server to warn that the OBD module is disconnected from the electronic control unit of the vehicle.
An OBD vehicle-mounted monitoring terminal, characterized by comprising: an MCU, an OBD module, and a communication module, the OBD module is connected to an OBD interface on a vehicle, so that the OBD module communicates with an electronic control unit on the vehicle;

The MCU is used for:

Detecting whether the communication between the OBD module and the electronic control unit on the vehicle is abnormal;

If yes, determine whether the vehicle supports the high-speed CAN communication protocol;

If the vehicle supports the high-speed CAN communication protocol, detecting whether the CAN loop between the OBD module and the electronic control unit on the vehicle is turned on;

If not, send a disconnection warning of the OBD module to the background management server through the communication module to warn that the OBD module is disconnected from the electronic control unit of the vehicle.
The terminal according to claim 10, wherein the OBD module comprises an OBD connector and an OBD chip, the OBD chip is electrically connected to the OBD connector and the MCU, and the OBD connector is connected to the vehicle OBD interface connection.
The terminal according to claim 10, wherein when the vehicle supports the high-speed CAN communication protocol, the OBD module and the OBD interface on the vehicle are connected via a high-speed CAN bus, and the high-speed CAN The bus constitutes a CAN loop;

The MCU is used for:

Output a high-level signal to control the first data line terminal in the CAN loop to input a first voltage;

It is detected whether the second voltage of the second data line terminal in the CAN loop matches the first voltage, and if it does not match, the CAN loop does not conduct.
The terminal according to claim 10, wherein when an abnormal communication between the OBD module and the electronic control unit on the vehicle is detected, the MCU is further configured to:

Wake up the OBD vehicle-mounted monitoring terminal in the dormant state, and activate the configuration of the OBD vehicle-mounted monitoring terminal.
The terminal according to any one of claims 10 to 13, wherein the OBD vehicle-mounted monitoring terminal further comprises a positioning module electrically connected to the MCU;

The positioning module is used to detect the position information of the vehicle;

If the vehicle does not support the high-speed CAN communication protocol, the MCU is also used to:

Detecting whether the OBD module supports normal power supply;

If the normal power supply is supported and the power is turned on, or the normal power supply is not supported, the vehicle will be detected according to the position information of the vehicle and the time when the OBD module and the electronic control unit on the vehicle have abnormal communication. The connection status of the OBD module;

If the normal power supply is supported and the power supply is disconnected, a disconnection warning of the OBD module is sent to the background management server to warn that the OBD module is disconnected from the electronic control unit of the vehicle.
The terminal according to claim 14, wherein the OBD vehicle monitoring terminal further comprises an alarm module electrically connected to the MCU;

The alarm module is used to send an alarm when the OBD module is disconnected.
The terminal according to claim 10, wherein the OBD vehicle monitoring terminal further comprises a power management module, a battery, and a charger, and the power management module is respectively connected to the OBD module, the MCU, the battery, and The charger and the battery are respectively connected to the charger and the MCU.
An OBD monitoring system, applied to a car, the car is provided with an OBD interface, characterized in that the system comprises: the OBD vehicle monitoring terminal according to any one of claims 10 to 16, a network and a background management server;

The OBD vehicle-mounted monitoring terminal communicates with the car through the OBD interface, and communicates with the background management server through the network;

The OBD vehicle-mounted monitoring terminal is used to detect whether the CAN circuit between the OBD vehicle-mounted monitoring terminal and the electronic control unit of the car is conductive when the car supports the high-speed CAN communication protocol. The background management server sends a disconnection warning of the OBD vehicle-mounted monitoring terminal;

The background management server is configured to receive the disconnection warning and respond to the disconnection warning.