Urea pump signal tamper-proofing diagnosis method and device based on CAN communication

Abstract

The invention relates to a signal tamper-proof diagnosis method and device for a urea pump based on CAN communication, and belongs to the technical field of engine exhaust aftertreatment. The method comprises the steps that a request signal is sent to the urea pump; receiving a fault code signal and a feedback signal sent by the urea pump; based on the feedback signal, the working state and the urea injection amount of the urea pump are determined; and based on at least one of the working state, the urea injection amount and the fault code signal, whether the signal of the CAN bus where the urea pump is located is tampered or not is judged. According to the signal tamper-proof diagnosis method of the urea pump based on CAN communication, whether the message signal fed back by the intelligent urea pump is abnormal or not can be recognized by monitoring the working state and the urea injection amount of the urea pump in real time and combining the fault code signal, if the message signal is abnormal, it is considered that the signal of the CAN bus is tampered, and if not, the signal of the CAN bus is tampered. The intelligent urea pump is suitable for a vehicle adopting the intelligent urea pump based on CAN communication.

Description

Technical Field

[0001] The present invention relates to the technical field of engine exhaust aftertreatment, and in particular to a signal tamper-proof diagnosis method and device for a urea pump based on CAN communication. Background Art

[0002] In order to meet the increasingly stringent emission regulations, the mainstream technology route for nitrogen oxide emission pollutants from medium and heavy-duty diesel engines will adopt selective catalytic reduction (SCR). In this system, a urea pump is required to spray urea aqueous solution as a reducing agent. Currently, the commonly used urea pumps are mainly divided into two types according to the control method: the engine electronic control unit (EECU) hard-line direct-drive urea pump and the intelligent urea pump based on CAN communication. Among them, the intelligent urea pump based on CAN communication generally adopts the message definition that follows the J1939-71 protocol specification for product versatility and standardization. If the message used by the intelligent urea pump is deciphered, the CAN bus signal can be tampered with, affecting the normal operation of the intelligent urea pump, so that the urea pump cannot be injected according to the original expected urea injection amount of the EECU and no urea pump fault is reported.

[0003] The regulation "GB17691-2018 Heavy-Duty Diesel Vehicle Pollutant Emission Limits and Measurement Methods (China Phase VI)" stipulates that the system should detect single or cumulative reagent consumption and nozzle action. When urea is used as a reagent, the maximum monitoring cycle time for insufficient reagent consumption is 5 hours or equivalent to the duration of at least 2L of reagent consumption, whichever is longer. If the urea pump continues to not spray urea, the urea pump feedback injection volume is 0, and the cumulative urea consumption does not increase, the fault reporting conditions cannot be met, and the insufficient urea consumption fault will not be reported. The regulations also stipulate that the on-board diagnostics (OBD) system should monitor the purification performance of the emission after-processor in real time. If the emission after-processing fails during the life of the vehicle and causes the emission to exceed the OBD limit, the driver alarm system should be activated to prompt the driver to repair as soon as possible. When the alarm system includes an information display system, the cause of the alarm (for example, "low purification efficiency of the after-processing device", "deterioration of the after-processing performance", etc.) is displayed, and the Class A fault counter is activated to record the number of engine running hours after the Class A fault of the emission after-processor that causes the vehicle's emissions to exceed the OBD limit is confirmed and activated, until the driving performance limit system is enabled. In actual operation, in order to avoid frequent false alarms of this type of fault, the actual conversion efficiency of the SCR to NOx is not directly used as the condition for determining the fault, but the relative efficiency is used: the ratio of the actual conversion efficiency of the SCR to NOx to the theoretical conversion efficiency of the SCR to NOx, as the condition for determining the fault. This also brings a problem, that is, when the urea pump stops spraying urea for a long time, the theoretical conversion efficiency of SCR to NOx will drop to 0. In this case, the vehicle OBD system cannot correctly diagnose the SCR low efficiency fault.

[0004] In short, when the urea feedback amount of the smart urea pump is greater than zero, regardless of whether the feedback injection amount is the expected injection amount, it can be diagnosed through the high / low urea consumption fault and the low SCR efficiency fault. The only situation where the smart urea pump feedback injection amount is 0 and there is no urea pump fault cannot be effectively identified. By tampering with the CAN bus signal, the EECU can be deceived. In fact, there is no urea injection and no fault report, and there is no speed limit or torque limit. However, for the OEM, this situation violates emission regulations and may face fines.

[0005] The existing method proposes a diesel engine SCR emission reduction detection control system and control method. The control system can detect whether the liquid level in the urea tank drops and whether the urea injector is working normally through a detection control device, and then judge whether the entire SCR emission reduction system is working normally. When an abnormality is found, the signal is transmitted back to the vehicle ECU system in time, and the engine power is limited by the vehicle ECU.

[0006] The existing method requires an additional set of hardware equipment, which increases costs and is only applicable to vehicles that use hard-wired urea pumps and hard-wired direct-connected liquid level sensors. It directly collects the voltage signal of the liquid level sensor and the pulse signal of the urea injector to determine whether the urea liquid level has dropped and whether the urea pump is working properly. It is not applicable to intelligent urea pumps that use CAN communication and the three-in-one intelligent sensors of urea liquid level / temperature / quality currently used in the market. For vehicles that use CAN communication urea pumps and urea liquid level sensors, once a signal tampering device is installed on the CAN bus, it is impossible to simply judge whether the two are working properly through their messages. Summary of the invention

[0007] In view of this, it is necessary to provide a signal anti-tampering diagnosis method and device for a urea pump based on CAN communication, so as to solve the problem of how to identify abnormalities of a urea pump based on CAN communication.

[0008] In order to solve the above problems, the present invention provides a signal anti-tampering diagnosis method for a urea pump based on CAN communication, comprising: Sending a request signal to the urea pump; the request signal includes a urea pump state request signal and a urea injection amount request signal; receiving a fault code signal and a feedback signal sent by the urea pump; the feedback signal is sent based on the request signal; the feedback signal includes a urea pump state feedback signal and a urea injection amount feedback signal; Based on the feedback signal, determining the working state of the urea pump and the urea injection amount; Based on at least one of the working state, the urea injection amount and the fault code signal, it is determined whether a signal of the CAN bus where the urea pump is located is tampered with.

[0009] In a possible implementation, judging whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal includes: Within a first preset time period, when the working state is not in a ready state and the fault code signal indicates no fault, it is identified that a signal of the CAN bus where the urea pump is located is tampered with.

[0010] In a possible implementation, judging whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal includes: When the working 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 is tampered with.

[0011] In a possible implementation, judging whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal includes: When the working state is not switched based on the urea pump state request signal within a second preset time period, it is identified that a signal of the CAN bus where the urea pump is located is tampered with.

[0012] In a possible implementation, judging whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal includes: When the duration of the working state is greater than a third preset duration, it is identified that the signal of the CAN bus where the urea pump is located is tampered with.

[0013] In a possible implementation, judging whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal includes: When the working state is not in a preset state, or the switching path of the working state is not a preset path, it is identified that the signal of the CAN bus where the urea pump is located is tampered.

[0014] In a possible implementation, judging whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal includes: When the working state is in the injection state, the urea injection amount is 0, the fault code signal indicates no fault, and the urea injection amount request signal indicates that the time length for which the requested urea injection amount is greater than 0 is greater than a fourth preset time length, it is identified that the signal of the CAN bus where the urea pump is located is tampered with.

[0015] The present invention also provides a signal anti-tampering diagnostic device for a urea pump based on CAN communication, comprising: A sending module, used for sending a request signal to the urea pump; the request signal includes a urea pump state request signal and a urea injection amount request signal; A receiving module, used for receiving a fault code signal and a feedback signal sent by the urea pump; the feedback signal is sent based on the request signal; the feedback signal includes a urea pump state feedback signal and a urea injection amount feedback signal; A determination module, configured to determine the working state of the urea pump and the urea injection amount based on the feedback signal; The judging module is used to judge whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal.

[0016] On the other hand, the present invention also provides an electronic device, including a memory and a processor, wherein: The memory is used to store programs; The processor is coupled to the memory and is used to execute the program stored in the memory to implement the signal anti-tampering diagnosis method of the urea pump based on CAN communication described in any of the above implementations.

[0017] On the other hand, the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the signal anti-tampering diagnosis method for a urea pump based on CAN communication described in any of the above implementations is implemented.

[0018] On the other hand, the present invention further provides a computer program product, including a computer program, which, when executed by a processor, implements the signal anti-tampering diagnosis method for a urea pump based on CAN communication as described in any of the above implementations.

[0019] The beneficial effects of the present invention are as follows: the signal tamper-proof diagnosis method and device of the urea pump based on CAN communication provided by the present invention can obtain the working state and urea injection amount of the urea pump according to the feedback signal by acquiring 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, and make a comprehensive judgment according to one or more information in the working state, urea injection amount and fault code signal of the urea pump. For example, these information can be compared with the expected normal value or range to identify whether the CAN bus where the urea pump is located has been tampered with. By real-time monitoring of the working state and urea injection amount of the urea pump and combining with the fault code signal, it is identified whether the message signal fed back by the intelligent urea pump is abnormal. If there is an abnormality, it is considered that the signal of the CAN bus has been tampered with. The fault can be accurately identified and reported, and the situation of excessive emission without fault reporting can be avoided. The method is suitable for vehicles using an intelligent urea pump based on CAN communication, and can accurately detect whether the urea pump has an abnormality, ensure detection reliability, and avoid the situation of excessive emission without fault reporting, without increasing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the 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 work.

[0021] Figure 1A method flow chart of an embodiment of a signal tamper-proof diagnosis method for a urea pump based on CAN communication provided by the present invention; Figure 2 A flow chart of the working state of the urea pump provided by the present invention; Figure 3 A schematic structural diagram of an embodiment of a signal tamper-proof diagnostic device for a urea pump based on CAN communication provided by the present invention; Figure 4 A schematic structural diagram of an embodiment of an electronic device provided by the present invention. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0023] In the description of the embodiments of the present invention, unless otherwise specified, "multiple" means two or more than two. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" may mean: A exists alone, A and B exist at the same time, and B exists alone.

[0024] The descriptions of "first", "second", etc. involved in the embodiments of the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the technical features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0025] Figure 1 A method flow chart of an embodiment of a signal tamper-proof diagnosis method for a urea pump based on CAN communication provided by the present invention, as shown in FIG. Figure 1 As shown, the signal anti-tampering diagnosis method of the urea pump based on CAN communication includes: S101, sending a request signal to a urea pump; the request signal includes a urea pump state request signal and a urea injection amount request signal; S102, receiving a fault code signal and a feedback signal sent by the urea pump; the feedback signal is sent based on the request signal; the feedback signal includes a urea pump state feedback signal and a urea injection amount feedback signal; S103, determining the working state and urea injection amount of the urea pump based on the feedback signal; S104: Based on at least one of the working state, the urea injection amount and the fault code signal, determine whether a signal of the CAN bus where the urea pump is located is tampered with.

[0026] It should be noted that the executor of the signal anti-tampering diagnosis method of the urea pump based on CAN communication provided by the present invention can be EECU, and EECU can control the urea pump by sending a request signal, for example, it can send a urea pump status request signal to request the working status of the urea pump, and can send a urea injection amount request signal to request the urea injection amount of the urea pump.

[0027] The urea pump may send a corresponding feedback signal to the EECU according to the request signal, for example, may send a urea pump state feedback signal to determine the working state of the urea pump, and may send a urea injection amount feedback signal to determine the urea injection amount of the urea pump.

[0028] The urea pump can also send a fault code signal to the EECU periodically or in real time. The fault code signal is used to indicate whether there is a fault in the urea pump.

[0029] Compared with the prior art, the signal tamper-proof diagnosis method for a urea pump based on CAN communication provided by an embodiment of the present invention can obtain the working state and urea injection amount of the urea pump according to the feedback signal by acquiring 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, and make a comprehensive judgment based on one or more information of the working state, urea injection amount and fault code signal of the urea pump. For example, the information can be compared with the expected normal value or range to identify whether the signal of the CAN bus where the urea pump is located has been tampered with. By real-time monitoring of the working state and urea injection amount of the urea pump, and combining with the fault code signal, it is identified whether the message signal fed back by the intelligent urea pump is abnormal. If there is an abnormality, it is considered that the signal of the CAN bus has been tampered with. The fault can be accurately identified and reported, avoiding the situation where the emission exceeds the standard but no fault is reported. The method is suitable for vehicles using an intelligent urea pump based on CAN communication, accurately detecting whether the urea pump has an abnormality, ensuring detection reliability, avoiding the situation where the emission exceeds the standard but no fault is reported, and no cost is added.

[0030] In some embodiments of the present invention, judging whether the signal of the CAN bus where the urea pump is located is tampered based on at least one of the working state, the urea injection amount and the fault code signal includes: Within a first preset time period, when the working state is not in a ready state and the fault code signal indicates no fault, it is identified that a signal of the CAN bus where the urea pump is located is tampered with.

[0031] It is possible to directly identify whether the signal of the CAN bus where the urea pump is located has been tampered with based on the working status and fault code signal.

[0032] For example, after power is turned on at t15, timer 1 starts timing. When the time of timer 1 is greater than the first preset duration t1, the working status feedback of the urea pump is never 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.

[0033] The signal anti-tampering diagnosis method for a urea pump based on CAN communication provided in an embodiment of the present invention can directly identify tampering of the signal of the CAN bus where the urea pump is located according to the working status and fault code signal, thereby realizing abnormal identification of the intelligent urea pump using CAN communication.

[0034] In some embodiments of the present invention, judging whether the signal of the CAN bus where the urea pump is located is tampered based on at least one of the working state, the urea injection amount and the fault code signal includes: When the working 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 is tampered with.

[0035] It is possible to directly identify whether the signal of the CAN bus where the urea pump is located has been tampered with based on the working status and fault code signal.

[0036] For example, when the working state fed back by the urea pump 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 is tampered with.

[0037] The signal anti-tampering diagnosis method for a urea pump based on CAN communication provided in an embodiment of the present invention can directly identify tampering of the signal of the CAN bus where the urea pump is located according to the working status and fault code signal, thereby realizing abnormal identification of the intelligent urea pump using CAN communication.

[0038] In some embodiments of the present invention, judging whether the signal of the CAN bus where the urea pump is located is tampered based on at least one of the working state, the urea injection amount and the fault code signal includes: When the working state is not switched based on the urea pump state request signal within a second preset time period, it is identified that a signal of the CAN bus where the urea pump is located is tampered with.

[0039] It is possible to directly identify whether the signal of the CAN bus where the urea pump is located has been tampered with based on the working status.

[0040] For example, timer 2 can start timing from the urea pump status request signal issued by the EECU. When the time of timer 2 is greater than the second preset duration t2, the working status fed back by the urea pump is not switched according to the urea pump status request signal, and does not follow the change of the urea pump status request signal, that is, 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.

[0041] The signal anti-tampering diagnosis method of a urea pump based on CAN communication provided in an embodiment of the present invention directly identifies whether the signal of the CAN bus where the urea pump is located has been tampered with according to the working state, thereby realizing abnormal identification of the intelligent urea pump using CAN communication.

[0042] In some embodiments of the present invention, judging whether the signal of the CAN bus where the urea pump is located is tampered based on at least one of the working state, the urea injection amount and the fault code signal includes: When the duration of the working state is greater than a third preset duration, it is identified that the signal of the CAN bus where the urea pump is located is tampered with.

[0043] It is possible to directly identify whether the signal of the CAN bus where the urea pump is located has been tampered with based on the working status.

[0044] Exemplarily, when the duration of the working state is greater than the third preset time, that is, the urea pump cannot complete the relevant actions within the preset time, for example, the urea pump feedback state is continuously in the pre-injection (same pressure building) state for a time greater than the first calibration time, and is continuously in the purge state for a time greater 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.

[0045] The signal anti-tampering diagnosis method of a urea pump based on CAN communication provided in an embodiment of the present invention directly identifies whether the signal of the CAN bus where the urea pump is located has been tampered with according to the working state, thereby realizing abnormal identification of the intelligent urea pump using CAN communication.

[0046] In some embodiments of the present invention, judging whether the signal of the CAN bus where the urea pump is located is tampered based on at least one of the working state, the urea injection amount and the fault code signal includes: When the working state is not in a preset state, or the switching path of the working state is not a preset path, it is identified that the signal of the CAN bus where the urea pump is located is tampered.

[0047] It is possible to directly identify whether the signal of the CAN bus where the urea pump is located has been tampered with based on the working status.

[0048] For example, when the working state fed back by the urea pump is not in a preset state, or the switching path of the working state is not a preset path, it can be identified that the signal of the CAN bus where the urea pump is located is tampered with.

[0049] Optionally, Figure 2 The working state flow chart of the urea pump provided by the present invention is as follows: Figure 2 As shown, the preset states of the urea pump include preparation, pre-injection, injection, purge, and fault.

[0050] The urea pump state switching path and workflow are as follows: After t15 is powered on, the urea pump wakes up and starts self-checking. After completion, the urea pump automatically enters the ready state; When the EECU requests pre-injection, the urea pump starts to perform pre-injection / pressure building, and automatically enters the injection state after completion; When the urea pump is in the injection state, the urea injection quantity instruction requested by the EECU can be executed to inject the specified urea quantity; When the EECU requests purging or t15 is powered off, the urea pump starts purging. After the purging is completed, the urea pump automatically returns to the ready state and sleeps; At any stage of the entire process, if the urea pump detects a fault in itself, it will automatically enter the fault state and report the corresponding fault code information. Once the fault is restored, the urea pump returns to the ready state.

[0051] Therefore, when the working state fed back by the urea pump is not one of the five predefined states of preparation, pre-injection, injection, purge, and fault, or the urea pump state switches directly to the preparation state after pre-injection, or directly enters the injection state from the preparation state, etc., which are not predefined preset paths, it is recognized that the signal of the CAN bus where the urea pump is located has been tampered with.

[0052] The signal anti-tampering diagnosis method of a urea pump based on CAN communication provided in an embodiment of the present invention directly identifies whether the signal of the CAN bus where the urea pump is located has been tampered with according to the working state, thereby realizing abnormal identification of the intelligent urea pump using CAN communication.

[0053] In some embodiments of the present invention, judging whether the signal of the CAN bus where the urea pump is located is tampered based on at least one of the working state, the urea injection amount and the fault code signal includes: When the working state is in the injection state, the urea injection amount is 0, the fault code signal indicates no fault, and the urea injection amount request signal indicates that the time length for which the requested urea injection amount is greater than 0 is greater than a fourth preset time length, it is identified that the signal of the CAN bus where the urea pump is located is tampered with.

[0054] Whether the signal of the CAN bus where the urea pump is located has been tampered with can be identified based on the working status, urea injection amount and fault code signal.

[0055] Exemplarily, when the working state of the urea pump feedback is in the injection state, the feedback injection amount is equal to 0, and the fault code signal indicates no fault, and the accumulated time (timer 5) of the EECU requesting the urea injection amount to be greater than 0 is greater than the fourth preset time length t4, it is identified that the signal of the CAN bus where the urea pump is located is tampered.

[0056] The signal anti-tampering diagnosis method of a urea pump based on CAN communication provided in an embodiment of the present invention can identify abnormalities of an intelligent urea pump using CAN communication by identifying signal tampering of the CAN bus where the urea pump is located according to the working state, urea injection amount and fault code signal.

[0057] The signal tamper-proof diagnosis method for a urea pump based on CAN communication provided by the present invention 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 quantity signal, and urea pump fault code signal to identify whether the message signal fed back by the intelligent urea pump is abnormal. If there is an abnormality, it is considered that the signal of the CAN bus has been tampered with. At this time, the fault can be accurately identified and reported, avoiding the situation where the emission exceeds the standard but no fault is reported.

[0058] In addition, the present invention proposes a signal anti-tampering diagnosis method for a urea pump based on CAN communication. When any of the following six situations occurs, it is considered that the CAN network signal where the urea pump is located is tampered with, and the urea pump works abnormally. At this time, the EECU reports a fault, activates the driver alarm system, prompts the driver to repair it as soon as possible, and activates the Class A fault counter.

[0059] The six situations are as follows: (1) t15 starts timing after power-on (timer 1). When the time of timer 1 is greater than the calibratable time 1, and the urea pump feedback state is never in the ready state, and the urea pump fault signal is in the no-fault state; (2) The urea pump feedback status is in a fault state, and the urea pump fault signal is in a non-fault state; (3) The urea pump status request sent by the EECU starts timing (timer 2). When timer 2 is greater than the calibratable time 2, the urea pump feedback status does not change (the EECU request is not executed); (4) The urea pump cannot complete the relevant actions within the preset time: the urea pump feedback state continues to be in the pre-injection (same as pressure building), purging and other states for a time (timer 3, 4) greater than the calibratable time 3, 4; (5) The feedback state of the urea pump is not equal to the predefined state or the switching of the feedback state occurs in an undefined switching path; (6) The urea pump feedback state is in the injection state, the feedback injection amount is equal to 0, and the urea pump fault signal is in the fault-free state. When the three conditions are met at the same time, the accumulated time (timer 5) that the EECU requests the urea injection amount to be greater than 0 is greater than the calibratable time 5.

[0060] The signal anti-tampering diagnosis method for a urea pump based on CAN communication provided by the present invention is for an intelligent urea pump based on CAN communication. By comparing the signal sent by the EECU and the feedback signal of the urea pump with the normal working state of the urea pump, six situations in which the urea pump feedback injection amount is 0 and there is no urea pump fault are identified, and the six situations are regarded as tampering of the CAN bus signal. When the six situations in which the CAN bus signal is tampered occur, an OBD fault is reported, and the CAN bus signal anti-tampering function is realized to prevent the host factory from violating environmental protection regulations.

[0061] The signal anti-tampering diagnosis method for a urea pump based on CAN communication provided by the present invention is described in detail below in conjunction with specific scenarios: Embodiment 1: The present invention provides a diagnostic system for an intelligent urea pump to prevent CAN signal tampering, comprising a signal acquisition unit, a signal comparison unit and a fault judgment unit.

[0062] The signal acquisition unit includes acquisition of t15 power-on signal, EECU request urea pump status signal, EECU request urea injection amount signal, urea pump feedback status signal, urea pump feedback urea injection amount signal, and urea pump feedback fault code signal.

[0063] The signal comparison unit performs six types of comparisons on the signal acquired by the signal acquisition unit.

[0064] The fault judgment unit judges whether the signal has been tampered with according to the comparison result of the signal comparison unit, thereby determining the abnormality of the urea pump and reporting the fault.

[0065] The typical working state process of urea pump is as follows: Figure 2 As shown in the figure, for the intelligent urea pump whose working state needs to be executed by EECU request, the predefined states include preparation, pre-injection, injection, purge and fault. The state switching path and workflow of the urea pump are briefly described as follows: After t15 is powered on, the urea pump wakes up and starts self-checking. After completion, the urea pump automatically enters the ready state; When the EECU requests pre-injection, the urea pump starts to perform pre-injection / pressure building, and automatically enters the injection state after completion; When the urea pump is in the injection state, the urea injection quantity instruction requested by the EECU can be executed to inject the specified urea quantity; When the EECU requests purging or t15 is powered off, the urea pump starts purging. After the purging is completed, the urea pump automatically returns to the ready state and sleeps; At any stage of the entire process, if the urea pump detects a fault in itself, it will automatically enter the fault state and report the corresponding fault code information. Once the fault is restored, the urea pump returns to the ready state.

[0066] The EECU controls the urea pump by sending a status request signal (corresponding to the status of the urea pump requested by the EECU) and a urea injection amount request signal.

[0067] The urea pump sends a status feedback signal (corresponding to the current state of the urea pump), a urea injection amount feedback signal and a urea pump fault code signal to the EECU to facilitate the EECU to make request judgments and report urea pump faults.

[0068] For this type of intelligent urea pump, the diagnostic method to prevent CAN signal tampering is as follows: 1. After t15 is powered on, it starts timing (timer 1). When timer 1 is greater than 1min, and the urea pump feedback state has not been in the ready state and the urea pump fault signal is in the no-fault state; 2. The feedback status of the urea pump is in a fault state, and the fault signal of the urea pump is in a non-fault state, and both conditions are met for more than 10 seconds; 3. EECU requests urea pump pre-filling, purging, or requesting to clear any of the faults to start timing (timer 2). When timer 2 is greater than 10s and the urea pump feedback state does not change to the corresponding pre-filling, purging, or ready state; 4. The urea pump feedback state starts timing when it is in the pre-injection state (timer 3). When timer 3 is greater than 20 minutes, and the urea pump feedback state is always in the pre-injection state and has not changed to the injection state; or the urea pump feedback state starts timing when it is in the purge state (timer 4). When timer 4 is greater than 5 minutes, and the urea pump feedback state is always in the purge state and has not changed to the ready state; 5. The feedback status of the urea pump is not one of the five predefined states of preparation, pre-injection, injection, purge, and fault, or the urea pump state switching directly jumps to the preparation state after pre-injection, or directly enters the injection state from the preparation state, etc., which are not predefined state switching paths; 6. The urea pump feedback state is in the injection state, the feedback injection amount is equal to 0, and the urea pump fault signal is in the fault-free state. When the three conditions are met at the same time, the cumulative time (timer 5) that the EECU requests the urea injection amount to be greater than 0 is counted, and timer 5 is greater than 10 minutes; When any of the above six situations occurs, it is considered that the CAN bus data stream has been tampered with, the urea pump is working abnormally, the EECU reports a fault, activates the driver alarm system, prompts the driver to repair as soon as possible and activates the Class A fault counter.

[0069] Embodiment 2: For an intelligent urea pump that does not require an EECU request to execute its work, it determines the state it should be in and the action it needs to perform based on the required message signal sent by the EECU, and does not require the EECU to request pre-injection, purge, etc., but only needs to execute the urea injection request amount calculated by the EECU. For this type of intelligent urea pump, the signal obtained by the signal acquisition unit lacks an EECU request for the urea pump state signal, and the rest remains unchanged. The diagnostic method for preventing CAN signal tampering of the intelligent urea pump described in Embodiment 1 is still applicable, except that point 3 cannot occur.

[0070] The signal anti-tampering diagnosis method for the urea pump based on CAN communication provided by the present invention does not require the installation of other external devices at an additional cost, is applicable to vehicles using intelligent urea pumps based on CAN communication, and does not concern the form of the urea liquid level sensor. It can realize the CAN bus signal anti-tampering function, and can accurately identify the fault even if the CAN bus data stream is tampered with. It can accurately detect whether the urea pump is abnormal, and combine the high / low urea consumption fault and the SCR low efficiency fault diagnosis to ensure the reliability of the detection, avoid the situation where the emission exceeds the standard without a fault report, and can also realize the anti-tampering function of the CAN bus data stream, prevent the car driver or a third party from modifying the system privately, and ensure the reliable operation and diagnosis of the SCR urea injection system.

[0071] In addition, the term "EECU" briefly defined above is intended to be interpreted broadly and can be implemented as one or more general-purpose processors, application-specific integrated circuits or other electronic data processing components or even remote processors. Similarly, the term "urea pump" is also interpreted broadly and can be implemented as a motor-driven diaphragm pump, a diaphragm pump, a gear pump, etc.

[0072] The state of the urea pump is only 5 typical basic states, and it can also be adjusted according to the situation, such as adding cold protection state, hot protection state, after-sales service state, etc. At this time, the third point in the diagnostic method can be supplemented accordingly. If the EECU requests these states, the urea pump feedback state does not change to the corresponding state, the fourth point in the diagnostic method can be supplemented accordingly. If the urea pump feedback state is in these states for a long time, the fifth point in the diagnostic method can be supplemented accordingly. These predefined states and predefined state switching paths. The modified logic can all be considered that the CAN bus data has been tampered with and report a fault.

[0073] In order to better implement the signal tamper-proof diagnosis method of a urea pump based on CAN communication in the embodiment of the present invention, on the basis of the signal tamper-proof diagnosis method of a urea pump based on CAN communication, the embodiment of the present invention further provides a signal tamper-proof diagnosis device of a urea pump based on CAN communication. Figure 3 The structure diagram of an embodiment of the signal tamper-proof diagnostic device for a urea pump based on CAN communication provided by the present invention is as follows: Figure 3 As shown, the signal anti-tampering diagnostic device 300 of the urea pump based on CAN communication includes: The sending module 310 is used to send a request signal to the urea pump; the request signal includes a urea pump state request signal and a urea injection amount request signal; The receiving module 320 is used to receive the fault code signal and the feedback signal sent by the urea pump; the feedback signal is sent based on the request signal; the feedback signal includes a urea pump state feedback signal and a urea injection amount feedback signal; A determination module 330, configured to determine the working state of the urea pump and the urea injection amount based on the feedback signal; The judgment module 340 is used to judge whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal.

[0074] The signal anti-tampering diagnostic device 300 for a urea pump based on CAN communication provided in the above embodiment can implement the technical solution described in the above embodiment of the signal anti-tampering diagnostic method for a urea pump based on CAN communication. The specific implementation principles of the above modules or units can refer to the corresponding contents in the embodiment of the signal anti-tampering diagnostic method for a urea pump based on CAN communication, which will not be repeated here.

[0075] 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 4 Only some components of the electronic device 400 are shown, but it should be understood that it is not required to implement all of the components shown, and more or fewer components may be implemented instead.

[0076] In some embodiments, the processor 401 may be a central processing unit (CPU), a microprocessor or other data processing chip, which is used to run the program code or process data stored in the memory 402, such as the signal anti-tampering diagnosis method of the urea pump based on CAN communication in the present invention.

[0077] In some embodiments, processor 401 may be a single server or a server group. 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 in a cloud platform. In some embodiments, the cloud platform may include a private cloud, a public cloud, a hybrid cloud, a community cloud, a distributed cloud, an internal cloud, a multi-cloud, etc., or any combination thereof.

[0078] In some embodiments, the memory 402 may be an internal storage unit of the electronic device 400, such as a hard disk or memory of the electronic device 400. In other embodiments, the memory 402 may also be an external storage device of the electronic device 400, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the electronic device 400.

[0079] Furthermore, the memory 402 may include both an internal storage unit of the electronic device 400 and an external storage device. The memory 402 is used to store application software installed in the electronic device 400 and various data.

[0080] In some embodiments, the display 403 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, an organic light-emitting diode (OLED) touch device, etc. The display 403 is used to display information on the electronic device 400 and to display a visual user interface. The components 401-403 of the electronic device 400 communicate with each other via a system bus.

[0081] In one embodiment, when the processor 401 executes the signal anti-tampering diagnostic program of the urea pump based on CAN communication in the memory 402, the following steps may be implemented: Sending a request signal to the urea pump; the request signal includes a urea pump state request signal and a urea injection amount request signal; receiving a fault code signal and a feedback signal sent by the urea pump; the feedback signal is sent based on the request signal; the feedback signal includes a urea pump state feedback signal and a urea injection amount feedback signal; Based on the feedback signal, determining the working state of the urea pump and the urea injection amount; Based on at least one of the working state, the urea injection amount and the fault code signal, it is determined whether a signal of the CAN bus where the urea pump is located is tampered with.

[0082] It should be understood that: when the processor 401 executes the signal anti-tampering diagnosis program of the urea pump based on CAN communication in the memory 402, in addition to the above functions, other functions can also be realized. For details, please refer to the description of the corresponding method embodiment above.

[0083] Furthermore, the embodiment of the present invention does not specifically limit the type of the electronic device 400 mentioned, and the electronic device 400 may be a portable electronic device such as a mobile phone, a tablet computer, a personal digital assistant (PDA), a wearable device, a laptop computer, etc. Exemplary embodiments of portable electronic devices include but are not limited to portable electronic devices equipped with IOS, Android, Microsoft or other operating systems. The above-mentioned portable electronic device may 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 present invention, the electronic device 400 may not be a portable electronic device, but a desktop computer with a touch-sensitive surface (e.g., a touch panel).

[0084] Accordingly, an embodiment of the present invention further provides a computer-readable storage medium, which is used to store computer-readable programs or instructions. When the program or instructions are executed by a processor, the steps or functions of the signal anti-tampering diagnosis method for a urea pump based on CAN communication provided in the above-mentioned method embodiments can be implemented.

[0085] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware (such as a processor, a controller, etc.) through a computer program, and the computer program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0086] The signal anti-tampering diagnosis method and device for the urea pump based on CAN communication provided by the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A signal anti-tampering diagnosis method for a urea pump based on CAN communication, characterized in that: include: Sending a request signal to the urea pump; the request signal includes a urea pump state request signal and a urea injection amount request signal; Receiving a fault code signal and a feedback signal sent by the urea pump; The feedback signal is sent based on the request signal; the feedback signal includes a urea pump state feedback signal and a urea injection amount feedback signal; Based on the feedback signal, determining the working state of the urea pump and the urea injection amount; Based on at least one of the working state, the urea injection amount and the fault code signal, it is determined whether a signal of the CAN bus where the urea pump is located is tampered with.

2. The signal anti-tampering diagnosis method of a urea pump based on CAN communication according to claim 1, characterized in that: The determining whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal includes: Within a first preset time period, when the working state is not in a ready state and the fault code signal indicates no fault, it is identified that a signal of the CAN bus where the urea pump is located is tampered with.

3. The signal anti-tampering diagnosis method of a urea pump based on CAN communication according to claim 1, characterized in that: The determining whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal includes: When the working 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 is tampered with.

4. The signal anti-tampering diagnosis method of a urea pump based on CAN communication according to claim 1, characterized in that: The determining whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal includes: When the working state is not switched based on the urea pump state request signal within a second preset time period, it is identified that a signal of the CAN bus where the urea pump is located is tampered with.

5. The signal anti-tampering diagnosis method of a urea pump based on CAN communication according to claim 1, characterized in that: The determining whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal includes: When the duration of the working state is greater than a third preset duration, it is identified that the signal of the CAN bus where the urea pump is located is tampered with.

6. The signal anti-tampering diagnosis method of a urea pump based on CAN communication according to claim 1, characterized in that: The determining whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal includes: When the working state is not in a preset state, or the switching path of the working state is not a preset path, it is identified that the signal of the CAN bus where the urea pump is located is tampered.

7. The signal anti-tampering diagnosis method of a urea pump based on CAN communication according to claim 1, characterized in that: The determining whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal includes: When the working state is in the injection state, the urea injection amount is 0, the fault code signal indicates no fault, and the urea injection amount request signal indicates that the time length for which the requested urea injection amount is greater than 0 is greater than a fourth preset time length, it is identified that the signal of the CAN bus where the urea pump is located is tampered with.

8. A signal anti-tampering diagnostic device for a urea pump based on CAN communication, characterized in that: include: A sending module, used for sending a request signal to the urea pump; the request signal includes a urea pump state request signal and a urea injection amount request signal; A receiving module, used for receiving a fault code signal and a feedback signal sent by the urea pump; the feedback signal is sent based on the request signal; the feedback signal includes a urea pump state feedback signal and a urea injection amount feedback signal; A determination module, configured to determine the working state of the urea pump and the urea injection amount based on the feedback signal; The judging module is used to judge whether the signal of the CAN bus where the urea pump is located is tampered with based on at least one of the working state, the urea injection amount and the fault code signal.

9. An electronic device, characterized in that: comprising a memory and a processor, wherein: The memory is used to store programs; The processor is coupled to the memory and is used to execute the program stored in the memory to implement the signal anti-tampering diagnosis method of the urea pump based on CAN communication as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the signal anti-tampering diagnosis method for a urea pump based on CAN communication as claimed in any one of claims 1 to 7 is implemented.

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