A CAN-based diagnostic method and device for preventing signal tampering in urea pumps.

Abstract

This invention relates to a signal tamper-proof diagnostic method and device for a urea pump based on CAN communication, belonging to the field of engine exhaust aftertreatment technology. The method includes: sending a request signal to the urea pump; receiving a fault code signal and a feedback signal sent by the urea pump; determining the operating status and urea injection quantity of the urea pump based on the feedback signal; and determining whether the signal on the CAN bus where the urea pump is located has been tampered with based on at least one of the operating status, urea injection quantity, and fault code signal. The signal tamper-proof diagnostic method for a urea pump based on CAN communication provided by this invention can identify whether there are abnormalities in the message signals fed back by the intelligent urea pump by real-time monitoring of the urea pump's operating status and urea injection quantity, combined with fault code signals. If an abnormality is found, it is considered that the CAN bus signal has been tampered with. This method is applicable to vehicles using intelligent urea pumps based on CAN communication.

Description

Technical Field

[0001] This invention relates to the field of engine exhaust aftertreatment technology, and in particular to a signal anti-tampering diagnostic method and device for a urea pump based on CAN communication. Background Technology

[0002] To meet increasingly stringent emission regulations, Selective Catalytic Reduction (SCR) is a mainstream technology for reducing nitrogen oxide emissions from medium and heavy-duty diesel engines. In this system, a urea pump is used to inject a urea solution as a reducing agent. Currently, commonly used urea pumps are mainly classified into two types based on their control method: hard-wired direct-drive urea pumps based on the Engine Electronic Control Unit (EECU) and intelligent urea pumps based on CAN communication. For product universality and standardization, intelligent urea pumps based on CAN communication generally use message definitions conforming to the J1939-71 protocol specification. If the messages used by the intelligent urea pump are deciphered, the CAN bus signals can be tampered with, affecting the normal operation of the intelligent urea pump. This prevents the urea pump from injecting the urea according to the original expected injection quantity from the EECU, and results in no urea pump fault report.

[0003] When the urea feedback from the intelligent urea pump is greater than zero, regardless of whether the feedback injection amount is the expected injection amount, it can be diagnosed through high / low urea consumption faults and low SCR efficiency faults. However, it cannot effectively identify the situation where the intelligent urea pump feedback injection amount is 0 and there is no urea pump fault. By tampering with the CAN bus signal, it is possible to deceive the EECU, so that no urea is actually injected and no fault is reported, nor is speed or torque limited. However, for OEMs, this situation violates emission standards.

[0004] The existing method proposes a diesel engine SCR emission reduction detection and control system and control method. This control system can detect whether the liquid level in the urea tank has dropped and whether the urea injector is working properly through a detection and control device, and then determine whether the entire SCR emission reduction system is working properly. When an abnormality is detected, the signal is promptly transmitted back to the vehicle ECU system, and the vehicle ECU limits the engine power.

[0005] Existing methods require additional hardware, increasing costs, and are only applicable to vehicles using hard-wired urea pumps and directly hard-wired level sensors. They determine whether the urea level has dropped and whether the urea pump is functioning correctly by directly acquiring the voltage signal from the level sensor and the pulse signal from the urea injector. However, they are not suitable for smart urea pumps using CAN communication or the currently mainstream three-in-one smart urea level / temperature / mass sensors. For vehicles using CAN communication urea pumps and urea level sensors, once a signal tampering device is installed on the CAN bus, it becomes impossible to simply determine their functionality based on their messages. Summary of the Invention

[0006] In view of this, it is necessary to provide a signal anti-tampering diagnostic method and device for urea pumps based on CAN communication, so as to solve the problem of how to identify anomalies in urea pumps based on CAN communication.

[0007] To address the above problems, this invention provides a signal anti-tampering diagnostic method for urea pumps based on CAN communication, comprising:

[0008] Send a request signal to the urea pump; the request signal includes a urea pump status request signal and a urea injection quantity request signal;

[0009] The system receives fault code signals and feedback signals sent by the urea pump; the feedback signals are sent based on the request signals; the feedback signals include urea pump status feedback signals and urea injection quantity feedback signals.

[0010] Based on the feedback signal, the operating status of the urea pump and the urea injection volume are determined;

[0011] Based on at least one of the operating status, the urea injection volume, and the fault code signal, determine whether the signal on the CAN bus where the urea pump is located has been tampered with.

[0012] In one possible implementation, determining whether the signal on the CAN bus where the urea pump is located has been tampered with based on at least one of the operating state, the urea injection volume, and the fault code signal includes:

[0013] Within a first preset time period, if the working state is not in the ready state and the fault code signal indicates no fault, the signal of the CAN bus where the urea pump is located is identified as having been tampered with.

[0014] In one possible implementation, determining whether the signal on the CAN bus where the urea pump is located has been tampered with based on at least one of the operating state, the urea injection volume, and the fault code signal includes:

[0015] When the operating state is in a fault state and the fault code signal indicates no fault, it is identified that the signal of the CAN bus where the urea pump is located has been tampered with.

[0016] In one possible implementation, determining whether the signal on the CAN bus where the urea pump is located has been tampered with based on at least one of the operating state, the urea injection volume, and the fault code signal includes:

[0017] If the operating state is not switched based on the urea pump status request signal within a second preset time period, the signal of the CAN bus where the urea pump is located is identified as having been tampered with.

[0018] In one possible implementation, determining whether the signal on the CAN bus where the urea pump is located has been tampered with based on at least one of the operating state, the urea injection volume, and the fault code signal includes:

[0019] When the duration of the operating state exceeds a third preset duration, the signal identifying the CAN bus where the urea pump is located is tampered with.

[0020] In one possible implementation, determining whether the signal on the CAN bus where the urea pump is located has been tampered with based on at least one of the operating state, the urea injection volume, and the fault code signal includes:

[0021] When the working state is not in the preset state, or the switching path of the working state is not the preset path, the signal of the CAN bus where the urea pump is located is identified as being tampered with.

[0022] In one possible implementation, determining whether the signal on the CAN bus where the urea pump is located has been tampered with based on at least one of the operating state, the urea injection volume, and the fault code signal includes:

[0023] When the working state is in the injection state, the urea injection volume is 0, the fault code signal indicates no fault, and the urea injection volume request signal indicates that the duration of the request for a urea injection volume greater than 0 is greater than a fourth preset duration, the signal of the CAN bus where the urea pump is located is identified as having been tampered with.

[0024] The present invention also provides a CAN communication-based signal anti-tampering diagnostic device for a urea pump, comprising:

[0025] The sending module is used to send a request signal to the urea pump; the request signal includes a urea pump status request signal and a urea injection quantity request signal.

[0026] A receiving module is used to receive fault code signals and feedback signals sent by the urea pump; the feedback signals are sent based on the request signals; the feedback signals include urea pump status feedback signals and urea injection quantity feedback signals.

[0027] The determination module is used to determine the operating status of the urea pump and the urea injection volume based on the feedback signal;

[0028] The judgment module is used to determine whether the signal of the CAN bus where the urea pump is located has been tampered with based on at least one of the working status, the urea injection volume and the fault code signal.

[0029] On the other hand, the present invention also provides an electronic device, including a memory and a processor, wherein,

[0030] The memory is used to store programs;

[0031] The processor, coupled to the memory, is used to execute the program stored in the memory to implement the CAN communication-based signal anti-tampering diagnostic method for urea pumps as described in any of the above implementations.

[0032] On the other hand, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the signal anti-tampering diagnostic method for a urea pump based on CAN communication as described in any of the above implementations.

[0033] On the other hand, the present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the signal anti-tampering diagnostic method for a urea pump based on CAN communication as described in any of the above implementations.

[0034] The beneficial effects of this invention are as follows: The CAN communication-based urea pump signal anti-tampering diagnostic method and device provided by this invention acquires the request signal sent by the EECU, the fault code signal sent by the urea pump, and the feedback signal sent by the urea pump through the request signal. Based on the feedback signal, the operating status and urea injection quantity of the urea pump can be obtained. A comprehensive judgment can be made based on one or more of the information from the operating status, urea injection quantity, and fault code signal. For example, these information can be compared with the expected normal values ​​or ranges to identify whether the CAN bus where the urea pump is located has been tampered with. By real-time monitoring of the operating status and urea injection quantity of the urea pump, and combined with the fault code signal, it can identify whether there are any abnormalities in the message signals fed back by the intelligent urea pump. If an abnormality is found, it is considered that the CAN bus signal has been tampered with. This can accurately identify and report faults, avoiding situations where emissions exceed standards without fault reporting. It is applicable to vehicles using CAN communication-based intelligent urea pumps, accurately detecting whether there are any abnormalities in the urea pump, ensuring detection reliability, avoiding situations where emissions exceed standards without fault reporting, and without increasing costs. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A flowchart illustrating an embodiment of the CAN communication-based signal anti-tampering diagnostic method for urea pumps provided by the present invention;

[0037] Figure 2 The working state flowchart of the urea pump provided by the present invention;

[0038] Figure 3 A schematic diagram of an embodiment of the CAN communication-based urea pump signal anti-tampering diagnostic device provided by the present invention;

[0039] Figure 4 A schematic diagram of an embodiment of the electronic device provided by the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0041] In the description of the embodiments of the present invention, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0042] The terms "first," "second," etc., used in the embodiments of this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a technical feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0043] Figure 1 A flowchart illustrating an embodiment of the CAN communication-based signal anti-tampering diagnostic method for urea pumps provided by the present invention is shown below. Figure 1 As shown, the signal anti-tampering diagnostic method for urea pumps based on CAN communication includes:

[0044] S101. Send a request signal to the urea pump; the request signal includes a urea pump status request signal and a urea injection quantity request signal;

[0045] S102. Receive the fault code signal and feedback signal sent by the urea pump; the feedback signal is sent based on the request signal; the feedback signal includes a urea pump status feedback signal and a urea injection quantity feedback signal;

[0046] S103. Based on the feedback signal, determine the working status of the urea pump and the urea injection volume;

[0047] S104. Based on at least one of the operating status, the urea injection volume, and the fault code signal, determine whether the signal of the CAN bus where the urea pump is located has been tampered with.

[0048] It should be noted that the execution subject of the CAN communication-based signal anti-tampering diagnostic method for urea pump provided by the present invention can be an EECU. The EECU can control the urea pump by sending request signals. For example, it can send a urea pump status request signal to request the working status of the urea pump, and it can send a urea injection quantity request signal to request the urea injection quantity of the urea pump.

[0049] The urea pump can send corresponding feedback signals to the EECU based on the request signal. For example, it can send a urea pump status feedback signal to determine the working status of the urea pump, and it can send a urea injection quantity feedback signal to determine the urea injection quantity of the urea pump.

[0050] The urea pump can also send fault code signals to the EECU at regular intervals or in real time. The fault code signals are used to indicate whether there is a fault in the urea pump.

[0051] Compared with existing technologies, the CAN communication-based signal anti-tampering diagnostic method for urea pumps provided in this invention acquires request signals sent by the EECU, fault code signals sent by the urea pump, and feedback signals sent by the urea pump through the request signals. This allows the method to obtain the operating status and urea injection quantity of the urea pump based on the feedback signals. Furthermore, it makes a comprehensive judgment based on one or more of these factors, such as comparing them with expected normal values ​​or ranges to identify whether the CAN bus signal of the urea pump has been tampered with. By monitoring the operating status and urea injection quantity of the urea pump in real time and combining them with fault code signals, the method identifies whether there are any abnormalities in the message signals fed back by the intelligent urea pump. If an abnormality is found, it is considered that the CAN bus signal has been tampered with. This method can accurately identify and report faults, avoiding situations where emissions exceed standards without fault reporting. It is applicable to vehicles using CAN communication-based intelligent urea pumps, accurately detecting whether there are any abnormalities in the urea pump, ensuring detection reliability, avoiding situations where emissions exceed standards without fault reporting, and without increasing costs.

[0052] In some embodiments of the present invention, determining whether the signal on the CAN bus where the urea pump is located has been tampered with based on at least one of the operating state, the urea injection volume, and the fault code signal includes:

[0053] Within a first preset time period, if the working state is not in the ready state and the fault code signal indicates no fault, the signal of the CAN bus where the urea pump is located is identified as having been tampered with.

[0054] The CAN bus signal of the urea pump can be directly identified based on the working status and fault code signal to determine whether the signal has been tampered with.

[0055] For example, when t15 is powered on, timer 1 starts timing. When timer 1 is longer than the first preset duration t1, and the working status of the urea pump is not in the ready state and the fault code signal indicates no fault, it can be identified that the signal of the CAN bus where the urea pump is located has been tampered with.

[0056] The signal anti-tampering diagnostic method for urea pumps based on CAN communication provided in this invention can directly identify signal tampering on the CAN bus where the urea pump is located based on the working status and fault code signal, thereby realizing abnormal identification of intelligent urea pumps using CAN communication.

[0057] In some embodiments of the present invention, determining whether the signal on the CAN bus where the urea pump is located has been tampered with based on at least one of the operating state, the urea injection volume, and the fault code signal includes:

[0058] When the operating state is in a fault state and the fault code signal indicates no fault, it is identified that the signal of the CAN bus where the urea pump is located has been tampered with.

[0059] The CAN bus signal of the urea pump can be directly identified based on the working status and fault code signal to determine whether the signal has been tampered with.

[0060] For example, when the urea pump's operating status is in a fault state and the fault code signal indicates no fault, it can be identified that the signal of the CAN bus where the urea pump is located has been tampered with.

[0061] The signal anti-tampering diagnostic method for urea pumps based on CAN communication provided in this invention can directly identify signal tampering on the CAN bus where the urea pump is located based on the working status and fault code signal, thereby realizing abnormal identification of intelligent urea pumps using CAN communication.

[0062] In some embodiments of the present invention, determining whether the signal on the CAN bus where the urea pump is located has been tampered with based on at least one of the operating state, the urea injection volume, and the fault code signal includes:

[0063] If the operating state is not switched based on the urea pump status request signal within a second preset time period, the signal of the CAN bus where the urea pump is located is identified as having been tampered with.

[0064] The signal on the CAN bus where the urea pump is located can be directly identified based on the working status to determine whether it has been tampered with.

[0065] For example, timer 2 can be used to start timing from the urea pump status request signal issued by the EECU. When the timer 2 time is greater than the second preset duration t2, and the working state fed back by the urea pump does not switch according to the urea pump status request signal, and does not follow the change of the urea pump status request signal, that is, when the urea pump status request issued by the EECU is not executed, it can be identified that the signal of the CAN bus where the urea pump is located has been tampered with.

[0066] The signal anti-tampering diagnostic method for urea pumps based on CAN communication provided in this invention identifies abnormalities in smart urea pumps that use CAN communication by directly identifying signal tampering on the CAN bus where the urea pump is located based on its working status.

[0067] In some embodiments of the present invention, determining whether the signal on the CAN bus where the urea pump is located has been tampered with based on at least one of the operating state, the urea injection volume, and the fault code signal includes:

[0068] When the duration of the operating state exceeds a third preset duration, the signal identifying the CAN bus where the urea pump is located is tampered with.

[0069] The signal on the CAN bus where the urea pump is located can be directly identified based on the working status to determine whether it has been tampered with.

[0070] For example, when the duration of the working state is longer than the third preset duration, that is, when the urea pump cannot complete the relevant actions within the preset time, such as when the urea pump feedback state is in the pre-injection (same as pressure build-up) state for a longer than the first calibration time, or in the purging state for a longer than the second calibration time, it can be identified that the signal of the CAN bus where the urea pump is located has been tampered with.

[0071] The signal anti-tampering diagnostic method for urea pumps based on CAN communication provided in this invention identifies abnormalities in smart urea pumps that use CAN communication by directly identifying signal tampering on the CAN bus where the urea pump is located based on its working status.

[0072] In some embodiments of the present invention, determining whether the signal on the CAN bus where the urea pump is located has been tampered with based on at least one of the operating state, the urea injection volume, and the fault code signal includes:

[0073] When the working state is not in the preset state, or the switching path of the working state is not the preset path, the signal of the CAN bus where the urea pump is located is identified as being tampered with.

[0074] The signal on the CAN bus where the urea pump is located can be directly identified based on the working status to determine whether it has been tampered with.

[0075] For example, when the operating status feedback of the urea pump is not in the preset state, or the switching path of the operating status is not the preset path, it can be identified that the signal of the CAN bus where the urea pump is located has been tampered with.

[0076] Optionally, Figure 2 The flowchart of the working state of the urea pump provided by the present invention is as follows: Figure 2 As shown, the preset states of the urea pump include five types: ready, pre-injection, injection, purging, and fault.

[0077] The urea pump status switching path and workflow are as follows:

[0078] After the T15 is powered on, the urea pump wakes up and starts a self-test. After the self-test is completed, the urea pump automatically enters the ready state.

[0079] When the EECU requests pre-injection, the urea pump begins to perform pre-injection / pressure build-up and automatically enters injection mode upon completion.

[0080] Once the urea pump is in injection mode, it can execute the urea injection quantity command requested by the EECU to inject the specified amount of urea.

[0081] When the EECU requests purging or the t15 is powered off, the urea pump starts purging. After purging is completed, the urea pump automatically returns to the ready state and goes into hibernation.

[0082] At any stage of the process, if the urea pump detects a malfunction, it will automatically enter a fault state and report the corresponding fault code. Once the fault is resolved, the urea pump will return to the ready state.

[0083] Therefore, when the working status reported by the urea pump is not one of the five predefined states of preparation, pre-injection, injection, purging, or fault, or when the urea pump switches from pre-injection to preparation or directly from preparation to injection without a predefined path, it is identified that the signal of the CAN bus where the urea pump is located has been tampered with.

[0084] The signal anti-tampering diagnostic method for urea pumps based on CAN communication provided in this invention identifies abnormalities in smart urea pumps that use CAN communication by directly identifying signal tampering on the CAN bus where the urea pump is located based on its working status.

[0085] In some embodiments of the present invention, determining whether the signal on the CAN bus where the urea pump is located has been tampered with based on at least one of the operating state, the urea injection volume, and the fault code signal includes:

[0086] When the working state is in the injection state, the urea injection volume is 0, the fault code signal indicates no fault, and the urea injection volume request signal indicates that the duration of the request for a urea injection volume greater than 0 is greater than a fourth preset duration, the signal of the CAN bus where the urea pump is located is identified as having been tampered with.

[0087] The CAN bus signal of the urea pump can be identified as having been tampered with based on the operating status, urea injection volume, and fault code signal.

[0088] For example, when the urea pump feedback is in the injection state, the feedback injection quantity is equal to 0, and the fault code signal indicates no fault, when the cumulative time (timer 5) for the EECU to request the urea injection quantity to be greater than 0 is greater than the fourth preset duration t4, it is recognized that the signal of the CAN bus where the urea pump is located has been tampered with.

[0089] The signal anti-tampering diagnostic method for urea pumps based on CAN communication provided in this invention identifies abnormalities in smart urea pumps using CAN communication by recognizing tampering of the CAN bus signal where the urea pump is located based on the working status, urea injection volume, and fault code signal.

[0090] The present invention provides a CAN communication-based signal anti-tampering diagnostic method for urea pumps. This method compares the urea pump status request signal and urea injection quantity request signal sent by the EECU with the received urea pump feedback status signal, urea injection quantity feedback signal, and urea pump fault code signal to identify any anomalies in the intelligent urea pump's feedback message signals. If an anomaly is found, the CAN bus signal is considered to have been tampered with. This allows for accurate fault identification and reporting, preventing situations where emissions exceed standards without fault reporting.

[0091] Furthermore, this invention proposes a signal anti-tampering diagnostic method for urea pumps based on CAN communication. When any of the following six situations occur, it is considered that the CAN network signal of the urea pump has been tampered with and the urea pump is malfunctioning. At this time, the EECU reports a fault, activates the driver alarm system, and prompts the driver to repair and activate the Class A fault counter as soon as possible.

[0092] The six scenarios are as follows:

[0093] (1) After t15 is powered on, the timer starts (timer 1). When the timer 1 is longer than the calibrable time 1, and the urea pump feedback status is not in the ready state, and the urea pump fault signal is in the fault-free state.

[0094] (2) The urea pump feedback status is in a fault state, and the urea pump fault signal is in a fault-free state;

[0095] (3) The EECU sends a urea pump status request and starts timing (timer 2). When timer 2 is greater than the calibrable time 2, the urea pump feedback status does not change (the EECU request is not executed).

[0096] (4) The urea pump cannot complete the relevant actions within the preset time: the urea pump feedback status is continuously in the pre-injection (same as pressure building), purging and other states for a longer time (timers 3 and 4) than the calibrable time 3 and 4.

[0097] (5) The urea pump feedback status is not equal to the predefined usage status or the switching of the feedback status occurs without a predefined switching path;

[0098] (6) When the urea pump feedback state is in the injection state, the feedback injection quantity is equal to 0, and the urea pump fault signal is in the fault-free state, and all three conditions are met, the EECU requests that the cumulative time (timer 5) for the urea injection quantity to be greater than 0 is greater than the calibrable time 5.

[0099] This invention provides a CAN communication-based signal anti-tampering diagnostic method for urea pumps. For CAN communication-based intelligent urea pumps, it compares the signals emitted by the EECU and the urea pump feedback signals with the normal operating state of the urea pump. It identifies six scenarios where the urea pump feedback injection volume is 0 and there is no urea pump fault, and considers these as CAN bus signal tampering. When any of these six scenarios occur, an OBD fault is reported, thus achieving CAN bus signal anti-tampering functionality and preventing OEMs from violating environmental regulations.

[0100] The signal anti-tampering diagnostic method for urea pumps based on CAN communication provided by this invention will be described in detail below, with specific scenarios as examples:

[0101] Example 1: The present invention provides a diagnostic system for preventing CAN signal tampering of an intelligent urea pump, including a signal acquisition unit, a signal comparison unit and a fault judgment unit.

[0102] The signal acquisition unit includes the acquisition of the t15 power-on signal, the EECU request urea pump status signal, the EECU request urea injection quantity signal, the urea pump feedback status signal, the urea pump feedback urea injection quantity signal, and the urea pump feedback fault code signal.

[0103] The signal comparison unit performs six types of comparisons on the signals acquired by the signal acquisition unit.

[0104] The fault diagnosis unit determines whether the signal has been tampered with based on the comparison results from the signal comparison unit, thereby identifying the urea pump malfunction and reporting the fault.

[0105] The typical operating flow of a urea pump is as follows: Figure 2 As shown, for intelligent urea pumps whose operating status needs to be executed through an EECU request, the predefined states include five types: preparation, pre-injection, injection, purging, and fault. The state switching path and workflow of this urea pump are briefly described below:

[0106] After the T15 is powered on, the urea pump wakes up and starts a self-test. After the self-test is completed, the urea pump automatically enters the ready state.

[0107] When the EECU requests pre-injection, the urea pump begins to perform pre-injection / pressure build-up and automatically enters injection mode upon completion.

[0108] Once the urea pump is in injection mode, it can execute the urea injection quantity command requested by the EECU to inject the specified amount of urea.

[0109] When the EECU requests purging or the t15 is powered off, the urea pump starts purging. After purging is completed, the urea pump automatically returns to the ready state and goes into hibernation.

[0110] At any stage of the process, if the urea pump detects a malfunction, it will automatically enter a fault state and report the corresponding fault code. Once the fault is resolved, the urea pump will return to the ready state.

[0111] The EECU controls the urea pump by sending status request signals (corresponding to the EECU requesting the status of the urea pump) and urea injection quantity request signals.

[0112] The urea pump sends a status feedback signal (corresponding to the current status of the urea pump), a urea injection quantity feedback signal, and a urea pump fault code signal to the EECU to facilitate the EECU's request for judgment and to report urea pump faults.

[0113] For this type of intelligent urea pump, the diagnostic method for preventing CAN signal tampering is as follows:

[0114] 1. After T15 is powered on, it starts timing (timer 1). When timer 1 is greater than 1 minute, and the urea pump feedback status is not in the ready state and the urea pump fault signal is in the fault-free state;

[0115] 2. The urea pump feedback status is in a fault state, and the urea pump fault signal is in a fault-free state, both of which must be met for more than 10 seconds.

[0116] 3. The EECU requests the urea pump to pre-inject, purge, or request to clear the fault, and starts timing (timer 2). When timer 2 is greater than 10s, and the urea pump feedback status has not changed to the corresponding pre-inject, purge, or ready status;

[0117] 4. When the urea pump feedback status is in the pre-injection state, start timing (timer 3). When timer 3 is greater than 20 minutes, and the urea pump feedback status remains in the pre-injection state without changing to the injection state; or when the urea pump feedback status is in the purging state, start timing (timer 4). When timer 4 is greater than 5 minutes, and the urea pump feedback status remains in the purging state without changing to the preparation state.

[0118] 5. The urea pump feedback status is not one of the five predefined states: preparation, pre-injection, injection, purging, or fault. Or the urea pump status switching occurs when it jumps directly from the pre-injection state to the preparation state, or directly from the preparation state to the injection state, etc., without a predefined state switching path.

[0119] 6. When the urea pump feedback status is in the injection state, the feedback injection quantity is equal to 0, and the urea pump fault signal is in the fault-free state, and all three conditions are met simultaneously, the cumulative time when the EECU requests a urea injection quantity greater than 0 is counted (timer 5), and timer 5 is greater than 10 minutes.

[0120] When any of the above six situations occur, it is considered that the CAN bus data stream has been tampered with, the urea pump is malfunctioning, the EECU reports a fault, the driver alarm system is activated, and the driver is prompted to repair and activate the Class A fault counter as soon as possible.

[0121] Example 2: For intelligent urea pumps that do not require an EECU request to operate, the pump determines its own state and required actions based on the necessary message signals from the EECU. It does not require EECU requests for pre-injection or purging; it only needs to execute the urea injection request amount calculated by the EECU. For this type of intelligent urea pump, the signal acquisition unit acquires one less EECU request signal for the urea pump status, while the rest remain unchanged. The diagnostic method for preventing CAN signal tampering of the intelligent urea pump described in Example 1 is still applicable, except that point 3 is impossible.

[0122] This invention provides a CAN communication-based signal anti-tampering diagnostic method for urea pumps. It eliminates the need for additional cost or the installation of external devices, making it suitable for vehicles using CAN communication-based intelligent urea pumps. It is independent of the urea level sensor type and provides CAN bus signal anti-tampering functionality, accurately identifying faults even if the CAN bus data stream is tampered with. It can accurately detect urea pump abnormalities, combining high / low urea consumption fault diagnosis with low SCR efficiency fault diagnosis to ensure reliable detection and prevent situations where emissions exceed standards without fault reporting. It also prevents CAN bus data stream tampering, preventing unauthorized system modifications by drivers or third parties, ensuring reliable operation and diagnostics of the SCR urea injection system.

[0123] Furthermore, the term "EECU" is briefly defined above and is intended to be interpreted broadly, as it can be implemented as one or more general-purpose processors, application-specific integrated circuits, or other electronic data processing components or even remote processors configured appropriately. Similarly, the term "urea pump" is also interpreted broadly, and can be implemented as an electric motor-driven diaphragm pump, a diaphragm pump, a gear pump, etc.

[0124] The urea pump has only five typical basic states, which can be adjusted and added as needed, such as adding a cold protection state, a hot protection state, and an after-sales service state. In this case, point 3 of the diagnostic method can be supplemented accordingly. If the EECU requests these states and the urea pump feedback state does not change to the corresponding state, point 4 of the diagnostic method can be supplemented accordingly. If the urea pump feedback state remains in these states for an extended period, point 5 of the diagnostic method can supplement these predefined states and predefined state switching paths. Any modified logic will be considered as evidence of CAN bus data tampering and will report a fault.

[0125] To better implement the CAN communication-based signal anti-tampering diagnostic method for urea pumps in this invention embodiment, this invention embodiment also provides a CAN communication-based signal anti-tampering diagnostic device for urea pumps, building upon the CAN communication-based signal anti-tampering diagnostic method. Figure 3 This is a schematic diagram of an embodiment of the CAN communication-based signal anti-tampering diagnostic device for a urea pump provided by the present invention, as shown below. Figure 3 As shown, the CAN communication-based urea pump signal anti-tampering diagnostic device 300 includes:

[0126] The sending module 310 is used to send a request signal to the urea pump; the request signal includes a urea pump status request signal and a urea injection quantity request signal;

[0127] The receiving module 320 is used to receive the fault code signal and feedback signal sent by the urea pump; the feedback signal is sent based on the request signal; the feedback signal includes a urea pump status feedback signal and a urea injection quantity feedback signal.

[0128] The determination module 330 is used to determine the operating status of the urea pump and the urea injection volume based on the feedback signal;

[0129] The judgment module 340 is used to determine whether the signal of the CAN bus where the urea pump is located has been tampered with based on at least one of the working status, the urea injection volume and the fault code signal.

[0130] The CAN-based urea pump signal anti-tampering diagnostic device 300 provided in the above embodiments can realize the technical solutions described in the embodiments of the CAN-based urea pump signal anti-tampering diagnostic method. The specific implementation principles of each module or unit can be found in the corresponding content of the embodiments of the CAN-based urea pump signal anti-tampering diagnostic method, which will not be repeated here.

[0131] like Figure 4 As shown, the present invention also provides an electronic device 400. The electronic device 400 includes a processor 401, a memory 402, and a display 403. Figure 4Only some components of the electronic device 400 are shown, but it should be understood that it is not required to implement all the components shown, and more or fewer components may be implemented instead.

[0132] In some embodiments, processor 401 may be a central processing unit (CPU), microprocessor, or other data processing chip, used to run program code stored in memory 402 or process data, such as the CAN communication-based signal anti-tampering diagnostic method for urea pumps in this invention.

[0133] In some embodiments, processor 401 may be a single server or a group of servers. The server group may be centralized or distributed. In some embodiments, processor 401 may be local or remote. In some embodiments, processor 401 may be implemented on a cloud platform. In some embodiments, the cloud platform may include a private cloud, public cloud, hybrid cloud, community cloud, distributed cloud, internal cloud, multi-cloud, or any combination thereof.

[0134] In some embodiments, memory 402 may be an internal storage unit of electronic device 400, such as a hard disk or memory of electronic device 400. In other embodiments, memory 402 may also be an external storage device of electronic device 400, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc. equipped on electronic device 400.

[0135] Furthermore, the memory 402 may include both internal storage units of the electronic device 400 and external storage devices. The memory 402 is used to store application software and various types of data installed on the electronic device 400.

[0136] In some embodiments, display 403 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an organic light-emitting diode (OLED) touchscreen. Display 403 is used to display information from electronic device 400 and to display a visual user interface. Components 401-403 of electronic device 400 communicate with each other via a system bus.

[0137] In one embodiment, when the processor 401 executes the CAN communication-based urea pump signal tamper-proof diagnostic program in the memory 402, the following steps can be implemented:

[0138] Send a request signal to the urea pump; the request signal includes a urea pump status request signal and a urea injection quantity request signal;

[0139] The system receives fault code signals and feedback signals sent by the urea pump; the feedback signals are sent based on the request signals; the feedback signals include urea pump status feedback signals and urea injection quantity feedback signals.

[0140] Based on the feedback signal, the operating status of the urea pump and the urea injection volume are determined;

[0141] Based on at least one of the operating status, the urea injection volume, and the fault code signal, determine whether the signal on the CAN bus where the urea pump is located has been tampered with.

[0142] It should be understood that when the processor 401 executes the CAN communication-based urea pump signal anti-tampering diagnostic program in the memory 402, in addition to the functions mentioned above, it can also perform other functions, as detailed in the description of the corresponding method embodiments above.

[0143] Furthermore, this embodiment of the invention does not specifically limit the type of electronic device 400 mentioned. Electronic device 400 can be a mobile phone, tablet computer, personal digital assistant (PDA), wearable device, laptop computer, or other portable electronic device. Exemplary embodiments of portable electronic devices include, but are not limited to, portable electronic devices running iOS, Android, Microsoft, or other operating systems. The aforementioned portable electronic device can also be other portable electronic devices, such as a laptop computer with a touch-sensitive surface (e.g., a touch panel). It should also be understood that in some other embodiments of the invention, electronic device 400 may not be a portable electronic device, but rather a desktop computer with a touch-sensitive surface (e.g., a touch panel).

[0144] Accordingly, embodiments of the present invention also provide a computer-readable storage medium for storing computer-readable programs or instructions. When the programs or instructions are executed by a processor, they can implement the steps or functions in the CAN communication-based signal anti-tampering diagnostic method for urea pumps provided in the above-described method embodiments.

[0145] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware (such as a processor, controller, etc.), and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0146] The above provides a detailed description of the signal anti-tampering diagnostic method and device for urea pumps based on CAN communication provided by the present invention. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A signal tamper-proof diagnostic method for a urea pump based on CAN communication, characterized in that, include: Send a request signal to the urea pump; the request signal includes a urea pump status request signal and a urea injection quantity request signal; Receive fault code signals and feedback signals sent by the urea pump; The feedback signal is sent based on the request signal; the feedback signal includes a urea pump status feedback signal and a urea injection quantity feedback signal; Based on the feedback signal, the operating status of the urea pump and the urea injection volume are determined; Based on at least two of the operating status, the urea injection volume, and the fault code signal, determine whether the signal of the CAN bus where the urea pump is located has been tampered with. The determination of whether the signal on the CAN bus where the urea pump is located has been tampered with, based on at least two of the following: the operating status, the urea injection volume, and the fault code signal, includes: When the working state is in the injection state, the urea injection volume is 0, the fault code signal indicates no fault, and the urea injection volume request signal indicates that the duration of the request for a urea injection volume greater than 0 is greater than a fourth preset duration, the signal of the CAN bus where the urea pump is located is identified as having been tampered with.

2. The signal anti-tampering diagnostic method for a urea pump based on CAN communication according to claim 1, characterized in that, The determination of whether the signal on the CAN bus where the urea pump is located has been tampered with, based on at least two of the following: the operating status, the urea injection volume, and the fault code signal, includes: Within a first preset time period, if the working state is not in the ready state and the fault code signal indicates no fault, the signal of the CAN bus where the urea pump is located is identified as having been tampered with.

3. The signal anti-tampering diagnostic method for a urea pump based on CAN communication according to claim 1, characterized in that, The determination of whether the signal on the CAN bus where the urea pump is located has been tampered with, based on at least two of the following: the operating status, the urea injection volume, and the fault code signal, includes: When the operating state is in a fault state and the fault code signal indicates no fault, it is identified that the signal of the CAN bus where the urea pump is located has been tampered with.

4. The signal anti-tampering diagnostic method for a urea pump based on CAN communication according to claim 1, characterized in that, The determination of whether the signal on the CAN bus where the urea pump is located has been tampered with, based on at least two of the following: the operating status, the urea injection volume, and the fault code signal, includes: If the operating state is not switched based on the urea pump status request signal within a second preset time period, the signal of the CAN bus where the urea pump is located is identified as having been tampered with.

5. The signal anti-tampering diagnostic method for a urea pump based on CAN communication according to claim 1, characterized in that, The determination of whether the signal on the CAN bus where the urea pump is located has been tampered with, based on at least two of the following: the operating status, the urea injection volume, and the fault code signal, includes: When the duration of the operating state exceeds a third preset duration, the signal identifying the CAN bus where the urea pump is located is tampered with.

6. The signal anti-tampering diagnostic method for a urea pump based on CAN communication according to claim 1, characterized in that, The determination of whether the signal on the CAN bus where the urea pump is located has been tampered with, based on at least two of the following: the operating status, the urea injection volume, and the fault code signal, includes: When the working state is not in the preset state, or the switching path of the working state is not the preset path, the signal of the CAN bus where the urea pump is located is identified as being tampered with.

7. A tamper-proof diagnostic device for a urea pump signal based on CAN communication, characterized in that, The method for preventing signal tampering in a urea pump based on CAN communication as described in any one of claims 1 to 6 includes: The sending module is used to send a request signal to the urea pump; the request signal includes a urea pump status request signal and a urea injection quantity request signal. A receiving module is used to receive fault code signals and feedback signals sent by the urea pump; the feedback signals are sent based on the request signals; the feedback signals include urea pump status feedback signals and urea injection quantity feedback signals. The determination module is used to determine the operating status of the urea pump and the urea injection volume based on the feedback signal; The judgment module is used to determine whether the signal of the CAN bus where the urea pump is located has been tampered with based on at least two of the following: the working status, the urea injection volume, and the fault code signal.

8. An electronic device, characterized in that, Including memory and processor, among which, The memory is used to store programs; The processor, coupled to the memory, is used to execute the program stored in the memory to implement the CAN communication-based signal anti-tampering diagnostic method for urea pumps as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the signal anti-tampering diagnostic method for a urea pump based on CAN communication as described in any one of claims 1 to 6.

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