A test system and method for the performance of a urea pump

Abstract

The urea pump performance testing system and method provided by the present invention adopt software parameter calibration in a host computer and instruct a control circuit board to control a diesel vehicle after-treatment device to perform testing. The performance of the urea pump, such as infusion, injection, thawing, withdrawal and injection accuracy, can be tested, and a matching test of the urea pump in the entire diesel vehicle after-treatment device can also be performed. Compared with actual vehicle installation tests, the device structure system provided by the present invention is simple, economical and practical, and can complete the functional verification and parameter calibration work of actual vehicle installation tests, which can greatly improve the convenience of diesel engine after-treatment device testing and effectively shorten the development cycle of the urea pump and its components in the diesel vehicle after-treatment device.

Description

Technical Field

[0001] The present invention belongs to the technical field of diesel vehicle aftertreatment, and relates to a system and method for testing the performance of a diesel vehicle aftertreatment device, and in particular to a system and method for testing the performance of a urea pump in a diesel vehicle aftertreatment device. Background Art

[0002] The aftertreatment device of a diesel vehicle generally includes a urea tank for storing urea aqueous solution, a urea pump, a urea aqueous solution nozzle, and urea aqueous solution pipelines connecting them, as well as an electronic control unit of the device and its electronic control cables connecting to the above-mentioned equipment. When operating in a diesel vehicle after-treatment device, a urea pump must meet performance requirements such as urea-water solution transportation, injection, thawing, back-drawing, and injection accuracy. However, in the early product development and acceptance process of urea pumps in existing diesel vehicle after-treatment devices, the newly developed diesel vehicle after-treatment device is installed on a diesel vehicle engine bench or a complete vehicle for repeated testing and verification, which requires a lot of manpower, material resources, and financial resources for testing, and the development progress will also be greatly affected. At the same time, due to the complexity and diversity of the actual operating conditions of the diesel vehicle after-treatment device, it is difficult to exhaust the actual operating conditions of the diesel vehicle after-treatment device in the above-mentioned tests, resulting in some defects of the newly developed diesel vehicle after-treatment device being difficult or impossible to find. In this way, it is difficult to comprehensively investigate and improve the design defects of the newly developed device. That is, when the newly developed diesel vehicle after-treatment device is actually installed in a diesel vehicle for use, some faults that have not occurred in the above-mentioned test process will occur. Therefore, the development progress of new products of the diesel vehicle after-treatment device and the reliability of the equipment in actual operation are seriously affected. Summary of the Invention

[0003] In response to the above problems, the present invention proposes a test system and method for the performance of a urea pump of a diesel vehicle aftertreatment device, aiming to solve the problems of complex test environment, high cost and long development cycle in the current development process of a urea pump of a diesel vehicle aftertreatment device.

[0004] A urea pump performance test system proposed in the present invention mainly includes a host computer, a control circuit board, a mark collection gun and a test unit; wherein the test unit is composed of a urea tank for storing a urea aqueous solution, a urea pump having a urea aqueous solution delivery inlet, a delivery outlet, a withdrawal outlet and a return liquid port and a barcode, an electromagnetic nozzle with a drive coil, a negative pressure sensor and an on-off electromagnetic valve, and a urea aqueous solution pipeline connected therebetween, the negative pressure sensor and the on-off electromagnetic valve are sequentially arranged in series on the urea aqueous solution pipeline connecting the urea pump delivery inlet and the urea tank, the urea pump withdrawal outlet is directly connected to the urea pump delivery inlet, and the electromagnetic nozzle is connected in series on the urea aqueous solution pipeline connecting the urea pump delivery outlet and the urea tank; the urea pump includes electronic control components and mechanical components, the host computer is electrically connected to the control circuit board and the mark collection gun respectively, and the control circuit board is electrically connected to the negative pressure sensor, the on-off electromagnetic valve, the urea pump and the electromagnetic nozzle respectively.

[0005] The above-mentioned host computer includes a host, a display, a test system software and a keyboard, which are used to read the data barcode of each tested urea pump and establish a corresponding database; store and run the test system program at the same time; transmit the test instructions (speed, retraction and running time) to the control circuit board through the communication interface, and receive the actual voltage or current signal data detected by the control circuit board for the post-processing device; compare and verify with the corresponding calibration parameters, store the test results, and automatically alarm when a fault occurs during the test, stop the test, and display the fault area.

[0006] The control circuit board receives the detection instructions from the host computer and converts them into corresponding voltage or current signals to control the test unit to detect electromagnetic nozzle coil faults and urea pump performance; the data detected during the above test process is sent to the host computer via electrical signals and stored in the database of the corresponding test urea pump;

[0007] The mark collection gun is used to read the barcode on the test urea pump, which contains the production time, serial number and version of the urea pump, and store the coding information in a newly created urea pump database of the host computer;

[0008] The negative pressure sensor is used to detect the maximum negative pressure value generated by the urea pump when building pressure, and feeds the data detected by the control circuit board back to the host computer and stores it in the database of the corresponding test urea pump;

[0009] The on-off solenoid valve mentioned above: the upper computer command control circuit board controls the on-off solenoid valve to control the on and off of the urea pump delivery inlet liquid inlet pipeline;

[0010] The electromagnetic nozzle described above is used to simulate the urea nozzle in the diesel vehicle after-treatment device to spray urea aqueous solution into the exhaust pipe.

[0011] The above-mentioned urea pump performance at least includes urea pump electronic control component fault detection, and urea pump pressure buildup, zero injection volume pressure stabilization, injection accuracy and backflow detection.

[0012] The mechanical components of the urea pump mainly include an infusion motor pump, a back-draw electromagnetic pump, a filter, and a one-way liquid return valve. The electronic control components of the urea pump mainly include an infusion motor pump motor, a back-draw electromagnetic pump electromagnet, a pressure sensor, an ambient temperature sensor T2, a heater and a heater temperature sensor T1. The urea pump delivery inlet, the infusion motor pump, the filter and the urea pump outlet are connected in sequence through a urea aqueous solution pipeline to form a urea pump infusion circuit. The back-draw electromagnetic pump is connected in parallel at both ends of the infusion motor pump through the urea aqueous solution pipeline. The pressure sensor and the one-way liquid return valve are sequentially arranged between the filter and the urea pump outlet. The urea aqueous solution pipeline is branched to the urea aqueous solution pipeline of the urea pump return port. The heater and the heater temperature sensor are respectively arranged on the filter and the urea aqueous solution pipeline in the urea pump. The ambient temperature sensor is arranged in the urea pump.

[0013] The present invention also provides a testing method based on the above-mentioned testing system, the main testing steps of which include:

[0014] Step 1: Electromagnetic nozzle coil detection

[0015] Turn on the power of the test system, and the host computer instructs the control circuit board to detect the electromagnetic nozzle coil:

[0016] If there is an open or short circuit fault in the electromagnetic nozzle coil, the control circuit board will feed back the information to the host computer, the fault light will turn on red, and the test system will stop the next test. After troubleshooting the electromagnetic nozzle, the system will be reset on the host computer and the electromagnetic nozzle will be retested. If the test passes, the test system will proceed to the next test.

[0017] If there is no fault in the electromagnetic nozzle coil, proceed to the next step of testing;

[0018] Step 2: Scan the barcode of urea pump

[0019] The marking acquisition gun scans the barcode on the test urea pump to identify its information and sends the identified information to the host computer. The host computer receives the above information and establishes its database, and stores its subsequent performance test information and fault information in the test urea pump database marked by this barcode. After the test of the urea pump is completed, it can be called up for viewing at any time:

[0020] If the barcode scanning fails, the host computer will light up a red light to alarm: 1) stop the subsequent testing work, eliminate the fault, and rescan the barcode; or 2) replace the test urea pump of the above test system with another test urea pump and scan the barcode of the test urea pump; or 3) end the test directly;

[0021] If the barcode scan is successful, the host computer receives the scan information and establishes the urea pump database, and then proceeds to the next step of detection;

[0022] Step 3: Urea pump communication test

[0023] Start the test system on the host computer, and the communication protocol between the host computer and the control circuit board performs handshake communication with the urea pump:

[0024] If the communication test fails, the host computer lights up red and stops the test (the host computer records the fault and saves it in the database of the corresponding urea pump): 1) After troubleshooting, reinstall the urea pump and test again; or 2) install a new urea pump and start the test from step 1; or 3) end the test directly;

[0025] If the communication test is successful, proceed to the next step of the test;

[0026] Step 4: Urea pump temperature sensor fault detection

[0027] The host computer instructs the control circuit board to detect the ambient temperature sensor T2 and the heating element temperature sensor T1 in the urea pump respectively, and compares the detected temperature signals with the temperature calibration values in the host computer respectively, so as to determine whether the ambient temperature sensor and the heating element temperature sensor in the urea pump are faulty: If there is a fault in the above two temperature sensors, the host computer will display the fault type in red and store the fault information in the database of the corresponding test urea pump, and continue to the next step of detection;

[0028] Step 5: Fault detection of urea pump electronic control components

[0029] The host computer command control circuit board detects the resistance of the electronic control components of the urea pump except the temperature sensor, and compares them with the corresponding resistance values calibrated in the host computer to determine whether the above electronic control components are open or short-circuited:

[0030] If a fault is detected, the host computer will display the corresponding fault in red, stop the test, and store the test fault information in the database of the corresponding urea pump: 1) After troubleshooting, reinstall the urea pump and perform a second test; or 2) install a new urea pump and start the test from step 1; or 3) end the test directly;

[0031] If there is no fault in the test, proceed to the next step;

[0032] Step 6: Urea pump pressure buildup test

[0033] Including negative pressure detection and pressure building detection of the infusion motor pump in the urea pump:

[0034] ①Negative pressure detection:

[0035] The host computer instructs the control circuit board to control the on-off solenoid valve to close the liquid inlet pipe of the urea pump; at the same time, the host computer instructs the control circuit board to start the infusion motor pump to run at 2600 rpm for a preset time, and at a predetermined time during the operation of the infusion motor pump, the negative pressure sensor detects the negative pressure signal of the infusion motor pump. The control circuit board feeds back the negative pressure signal at this moment to the host computer and compares it with the negative pressure calibration value (if the negative pressure detection value is less than the negative pressure calibration value, it is qualified, otherwise it is unqualified):

[0036] If the negative pressure test value is not qualified and lights up red, and the negative pressure test value is saved in the host computer: 1) After the fault is resolved, reinstall the urea pump and perform a second test; or 2) install a new urea pump and start the test from step 1; or 3) end the test directly;

[0037] If qualified, the green light will be on, and the negative pressure test value will be saved in the host computer, and the next test will be continued;

[0038] ②Pressure buildup detection:

[0039] The host computer instruction control circuit board controls the on-off solenoid valve to open the liquid inlet pipe of the urea pump. At the same time, the host computer instruction control circuit board controls the start of the infusion motor pump to build pressure. When the pressure sensor detects that the output pressure of the infusion motor pump reaches 8.7 bar, the control circuit board adjusts the power supply voltage of the infusion motor pump to keep the pressure stable for a preset time, and then determines whether the output pressure of the infusion motor pump is stable within the pressure calibration range:

[0040] 1) If the output pressure of the infusion motor pump is stable within the pressure calibration range, the control circuit board sends the pressure build-up time to the host computer for comparison with the pressure build-up calibration time and stores it; if the pressure build-up time is greater than the pressure build-up calibration time, the host computer will output a pressure build-up timeout, turn on the red light, stop the test, and save the fault information: 1) After the fault is resolved, reinstall the urea pump for a second test; or 2) install a new urea pump and start the test from step 1; or 3) end the test directly; if the pressure build-up time is less than or equal to the pressure build-up calibration time, the test is qualified and the next step of the test is continued;

[0041] 2) If the output pressure of the infusion motor pump cannot be stabilized within the pressure calibration range, the host computer will light up a red light to stop the test, indicating that the output pressure of the infusion motor pump is unstable and store the instantaneous value of the pressure (in order for the urea pump to discharge the urea aqueous solution, the host computer will start the withdrawal electromagnetic pump through the control circuit board to withdraw the preset time): 1) After troubleshooting, reinstall the urea pump and conduct a second test; or 2) install a new urea pump and start the test from step 1; or 3) end the test directly;

[0042] 3) If there is no fault, proceed to the next step of testing;

[0043] Step 7: Urea pump zero injection volume voltage stabilization test

[0044] Go to step 6, that is, after the urea pump pressure build-up test passes, at zero injection volume, the host computer instructs the control circuit board to collect the pressure sensor signal and the infusion motor pump speed signal, and sends the detected pressure signal and motor speed value to the host computer, which determines the stability of the output pressure of the urea pump infusion motor pump:

[0045] 1) If the infusion motor pump speed is within the normal speed calibration range, but the pressure fluctuation exceeds the pressure calibration range, the host computer lights up red, indicating that the infusion motor pump output pressure exceeds the tolerance fault, stops the test, and the host computer saves the fault information: 1) After troubleshooting, reinstall the urea pump and retest in step 6, or 2) install a new urea pump and start the test from step 1; or 3) directly end the test;

[0046] 2) If the infusion motor pump speed is also not within the normal speed calibration range and the pressure is also unstable, the host computer lights up red, indicating a one-way return valve failure, stops testing, and saves the fault information: 1) After troubleshooting, reinstall the urea pump and retest from step 6, or 2) install a new urea pump and start testing from step 1; or 3) end the test directly;

[0047] 3) If the infusion pump motor speed is within the normal speed calibration range and the pressure fluctuation does not exceed the pressure calibration range, proceed to the next step of the test;

[0048] Step 8: Urea pump injection accuracy test

[0049] Go to step 7, that is, after the urea pump zero injection volume voltage stabilization test passes, the host computer instructs the control circuit board to control the start of the infusion motor pump to automatically and sequentially perform at least three intermittent unit injection volume tests between the zero injection volume and the maximum injection volume of the urea pump calibrated in the host computer. After each unit injection volume lasts for the preset injection time, the pressure sensor detects the output pressure fluctuation of the infusion motor pump, and the detection data is uploaded to the host computer by the control circuit board. The host computer determines whether the pressure fluctuation in each unit injection volume test exceeds the pressure fluctuation calibration range:

[0050] 1) If the pressure fluctuation in each unit injection volume test does not exceed the pressure fluctuation calibration range, proceed to the next test;

[0051] 2) If the pressure fluctuation during each unit injection quantity test exceeds the pressure fluctuation calibration range, the host computer lights up a red light, stops testing, and stores the fault data in the database of the corresponding tested urea pump: 1) After troubleshooting, reinstall the urea pump and retest from step 6, or 2) install a new urea pump and start testing from step 1; or 3) end the test directly;

[0052] Step 9: Urea pump backflow test

[0053] Go to step 7, that is, after the urea pump injection accuracy test is passed, the host computer instructs the control circuit board to start the withdrawal electromagnetic pump to withdraw the urea aqueous solution in the urea pump: start the withdrawal electromagnetic pump and open the on-off electromagnetic valve at the same time. The withdrawal electromagnetic pump withdraws within the preset withdrawal time. During the withdrawal process, the minimum negative pressure signal of the negative pressure sensor is collected and compared with the negative pressure calibration value of the host computer (if the negative pressure detection value is less than the negative pressure calibration value, it is qualified, otherwise it is unqualified):

[0054] 1) If the negative pressure detection value is greater than the negative pressure calibration value, it is a backflow negative pressure fault, the host computer lights up a red light, stops testing, and saves the negative pressure value in the database of the host computer corresponding to the urea pump tested: 1) After troubleshooting, reinstall the urea pump and retest from step 6, or 2) install a new urea pump and start testing from step 1; or 3) end the test directly;

[0055] 2) If the negative pressure detection value is less than the negative pressure calibration value, the test ends.

[0056] There is no requirement for the order of testing for Step 1 and Step 2 above. The condition for testing Step 3 is: Step 1 and Step 2 have been completed.

[0057] There is no order of testing between step 4 and step 5 described above. The condition for testing in step 6 is: the testing of step 4 and step 5 has been completed.

[0058] In the above-mentioned step 4, the temperature calibration values of the temperature measuring element of the ambient temperature in the urea pump and the temperature measuring element of the heating element are determined according to the indoor ambient temperature of the test urea pump;

[0059] In the above-mentioned step 5: the resistance calibration values of the infusion motor pump motor, the return electromagnetic pump electromagnet, the pressure sensor, and the heating element are respectively their normal resistance values;

[0060] In step 6 above: the infusion motor pump motor runs at 2600 rpm for a preset time of 58 seconds; the negative pressure sensor detects the negative pressure signal of the infusion motor pump at a predetermined time of 50 seconds during the operation of the infusion motor pump, and the negative pressure calibration value at this time is -150 mbar; when the pressure sensor detects that the output pressure of the infusion motor pump reaches 8.7 bar, the control circuit board adjusts the power supply voltage of the infusion motor pump to keep the pressure stable for a preset time of 3 seconds; the output pressure of the infusion motor pump is stable within the pressure calibration range; the pressure build-up calibration time is 65 seconds; and the withdrawal preset time is 10 seconds;

[0061] In step 7 above, the pressure is calibrated to 9±0.3 bar, and the normal speed calibration range of the infusion motor pump is 1200-1600 rpm;

[0062] In step 8 above, each unit injection volume lasts for a preset injection time, and the output pressure fluctuation calibration range of the infusion motor pump is within the range of 9±0.3 bar;

[0063] In step 9 above, the preset time for the electromagnetic pump to withdraw is 60 seconds; the minimum negative pressure calibration value during the withdrawal process is -100 mbar.

[0064] The present invention calibrates software parameters in a host computer and instructs a control circuit board to control a diesel vehicle after-treatment device to perform testing. The performance of the urea pump, such as liquid infusion, injection, thawing, withdrawal, and injection accuracy, can be tested, and a matching test of the urea pump in the entire diesel vehicle after-treatment device can also be performed. Compared with actual vehicle installation tests, the test system provided by the present invention is simple, economical, and practical, and can complete the functional verification and parameter calibration work of actual vehicle installation tests, thereby greatly improving the convenience of diesel engine after-treatment device testing and effectively shortening the development cycle of the urea pump and its components in the diesel vehicle after-treatment device. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 The performance test system diagram of the diesel vehicle aftertreatment device based on the non-air-assisted urea pump is provided.

[0066] Figure 2 for Figure 1 Functional block diagram of the test system shown;

[0067] Figure 3 for Figure 1 Flowchart of the test method of the test system shown. DETAILED DESCRIPTION

[0068] The performance testing system of a diesel vehicle aftertreatment device based on a non-air-assisted urea pump provided by the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0069] like Figure 1, which is a diagram of the urea pump performance test system for a diesel vehicle aftertreatment device based on a non-air-assisted urea pump, mainly including a host computer (a signal generator simulating a diesel vehicle engine and aftertreatment) 1, a control circuit board (simulating an electronic control unit of a diesel vehicle aftertreatment device) 2, a mark collection gun 3, and a test unit (i.e., a urea tank 11 for storing urea aqueous solution, a urea pump 4, an electromagnetic nozzle 8, a negative pressure sensor 13, an on-off electromagnetic valve 12, and a urea aqueous solution pipeline connecting them). The mechanical components of the urea pump 4 mainly include an infusion motor pump 5, a back-draw electromagnetic pump 6, a filter 7, and a one-way return valve 10. The electronic control components of the urea pump mainly include an infusion motor pump 5 motor, a back-draw electromagnetic pump 6 electromagnet, a pressure sensor 9, an ambient temperature sensor T216, a charging The heating plate 14 and the heating plate temperature sensor T115; wherein the delivery inlet of the urea pump 4, the infusion motor pump 5, the filter 7 and the outlet of the urea pump 4 are connected in sequence through the urea aqueous solution pipeline to form the infusion circuit of the urea pump 4, the back-draw electromagnetic pump 6 is connected in parallel at both ends of the infusion motor pump 5 through the urea aqueous solution pipeline, the pressure sensor 9 and the one-way liquid return valve 10 are sequentially arranged between the filter 7 and the outlet of the urea pump 4, the urea aqueous solution pipeline branch is connected to the urea aqueous solution pipeline of the return liquid port of the urea pump 4, the heating plate 14 and the heating plate temperature sensor 15 are respectively arranged on the urea aqueous solution pipeline in the filter 7 and the urea pump 4, and the ambient temperature sensor 16 is arranged in the urea pump 4 (the solid arrows in the figure are the liquid inlet line, and the hollow arrows are the liquid return line).

[0070] like Figure 2 As shown, the host computer 1 is directly connected to the tag collection gun 3 via a cable, which is used to scan the unique coding information of the urea pump 4 and store this information in the corresponding test urea pump database in the host computer 1. Simultaneously, the host computer 1 is directly connected to the control circuit board 2 via a cable, and various test instructions are sent to the control circuit board 2. The control circuit board 2 is connected to the electromagnetic nozzle 8 and the urea pump 4 via cables for control and testing, and the test data is fed back to the host computer 1 for judgment, analysis, and storage. Furthermore, the control circuit board 2 is also connected to a negative pressure sensor 13 and an on-off solenoid valve 12 via cables. This controls the infusion motor pump 5 to close its inlet pipe via the on-off solenoid valve 12 when building pressure. The negative pressure is detected by the negative pressure sensor 13. All test data (including the ambient temperature and pressure inside the urea pump, as well as fault data) is fed back and recorded in the host computer 1 database for judgment, analysis, and storage. The control circuit board 2 controls the urea pump 4 to extract liquid from the urea tank 11 through the urea aqueous solution pipeline, pass through the filter 7, and then flow back into the urea tank 11 through the one-way liquid return valve 10 and the electromagnetic nozzle 8 respectively.

[0071] Host computer 1: includes host, display, test system software and keyboard, used to read the data barcode of each tested urea pump and establish a corresponding database; store and run the test system program at the same time; transmit the test instructions (speed, retraction and running time) to the control circuit board 2 through the communication interface, and receive the actual voltage or current signal data detected by the control circuit board 2 on the post-processing device; compare and verify with the corresponding calibration parameters, store the test results, and automatically alarm when a fault occurs during the test, stop the test, and display the fault area.

[0072] The control circuit board 2 receives detection instructions from the host computer 1 and converts them into corresponding voltage or current signals to control the urea pump 4, including the electromagnetic nozzle 8, and perform at least the following tests: 1) electromagnetic nozzle test; 2) urea pump pressure buildup, pressure stabilization, and injection test; 3) control the withdrawal electromagnetic pump 6 to automatically perform a withdrawal test (60 seconds). The data detected during the above tests (including fault signals such as pressure buildup failure, unstable injection pressure, and one-way return valve blockage, as well as detection temperature sensor signals, detection pressure sensor signals, and open and short circuit signals of the infusion motor pump and the withdrawal electromagnetic pump electromagnet) are sent to the host computer 1 via electrical signals and stored in the database of the corresponding tested urea pump.

[0073] Mark collection gun 3: used to read the barcode on the test urea pump, which contains the production time, number, version, etc. of the test urea pump, and store its coding information in a newly created urea pump database of the host computer 1.

[0074] Negative pressure sensor 13: used to detect the maximum negative pressure value generated by the infusion motor pump 5 when building pressure, and the data detected by the control circuit board 2 is fed back to the host computer 1 and stored in the database corresponding to the test urea pump.

[0075] On-off solenoid valve 12: The host computer 1 sends instructions, and the control circuit board 2 controls the on-off solenoid valve 12 to control the on and off of the liquid inlet pipe of the infusion motor pump in the urea pump. The negative pressure sensor 13 installed on the liquid inlet pipe between the infusion motor pump 5 and the on-off solenoid valve 12 is used to detect the negative pressure during the pressure building process.

[0076] Electromagnetic nozzle 8: used to simulate the urea nozzle in the diesel vehicle after-treatment device to spray urea aqueous solution into the exhaust pipe.

[0077] The specific test methods are as follows:

[0078] System installation: Follow the Figure 1The test system shown in the figure is equipped with a host computer 1, a control circuit board 2, a mark collection gun 3, and a test unit (composed of a urea tank 11 for storing urea aqueous solution, a urea pump 4, an electromagnetic nozzle 8, a negative pressure sensor 13, an on-off electromagnetic valve 12 and the electromagnetic nozzle 8, and a urea aqueous solution pipeline connecting them). The pipes and the electronic control cables are connected and the electronic control cables are ready.

[0079] Step 1: Solenoid nozzle coil detection

[0080] Turn on the test system power, and the host computer 1 instructs the control circuit board 2 to test the electromagnetic nozzle 8 coil. If there is an open or short circuit fault in the electromagnetic nozzle coil, the control circuit board 2 will feedback the information to the host computer 1, and the fault light will turn red. The test system will stop the next test, and after troubleshooting the electromagnetic nozzle 8, reset the system on the host computer 1 and retest the electromagnetic nozzle 8. If the test passes, the test system will proceed to the next test (since the probability of the electromagnetic nozzle 8 coil being open or short circuited is small, the electromagnetic nozzle can be tested regularly or at a fixed frequency). If there is no fault in the electromagnetic nozzle coil, continue to the next test.

[0081] Step 2: Scan the barcode of the urea pump

[0082] The marking collection gun 3 scans the barcode on the test urea pump 4 to identify its information and sends the identified information to the host computer 1. The host computer 1 receives the above information and establishes its database. It stores its subsequent performance test information and its fault information in the test urea pump database marked by this barcode. After the test urea pump is completed, it can be retrieved and viewed at any time. If the barcode scan fails (identification, format), the host computer 1 will turn on a red light and alarm: 1) stop subsequent testing work, eliminate the fault, and rescan the barcode; or 2) replace the test urea pump of the above test system with another test urea pump and scan the barcode of the test urea pump; or 3) directly end the test. If the barcode scan is successful, the host computer 1 receives the scan information and establishes the urea pump database, and continues to the next step of testing.

[0083] Step 3: Urea pump communication test

[0084] Start the test system (see specific instructions) on host computer 1. The communication protocol between host computer 1 and control circuit board 2 establishes a handshake communication with the urea pump. If communication fails, the host computer lights up red and the test stops (the host computer records the fault and saves it in the database corresponding to the tested urea pump). 1) After troubleshooting, reinstall the urea pump and test again; or 2) install a new urea pump and start the test again from step 1; or 3) terminate the test immediately. If communication is successful, proceed to the next test step.

[0085] Step 4: Urea pump temperature sensor fault detection

[0086] The host computer 1 instructs the control circuit board 2 to detect the ambient temperature sensor T2 and the heating element temperature sensor T1 in the urea pump respectively, and compares the detected temperature signals with the temperature calibration values in the host computer 1 to determine whether the ambient temperature sensor and the heating element temperature sensor in the urea pump are faulty. If there is a fault in the above two temperature sensors, the host computer 1 will display the fault type in red and store the fault information in the database of the corresponding test urea pump, and continue to the next step of detection.

[0087] Step 5: Fault detection of urea pump electronic control components (except temperature sensor)

[0088] The host computer 1 instructs the control circuit board 2 to detect the resistance of the electronic control components (including the infusion pump motor, the solenoid of the withdrawal electromagnetic pump, the pressure sensor, and the heater 14) and compares them with the corresponding resistance values calibrated in the host computer 1 to determine whether the above electronic control components are open or short-circuited. If a fault is detected, the host computer 1 will display the corresponding fault in red, stop the test, and store the test fault information in the database of the corresponding test urea pump: 1) After troubleshooting, reinstall the urea pump and test it again; or 2) install a new urea pump and start the test again from step 1; or 3) directly end the test. If there is no fault, continue to the next test.

[0089] Step 6: Urea pump pressure test

[0090] Including negative pressure detection and pressure building detection of the infusion motor pump in the urea pump:

[0091] ②Negative pressure detection:

[0092] Host computer 1 instructs control circuit board 2 to control on / off solenoid valve 12 (normally open valve) to close the urea pump's inlet line. Simultaneously, host computer 1 instructs control circuit board 2 to start the infusion pump motor at 2600 rpm for a preset time of 58 seconds. At the 50th second (predeterminable time) of the infusion pump's operation, negative pressure sensor 13 collects the infusion pump's negative pressure signal. Control circuit board 2 feeds this current negative pressure signal back to host computer 1 and compares it with the negative pressure calibration value of -150 mbar. (If the negative pressure detection value is less than the negative pressure calibration value, it passes; otherwise, it fails.) If it fails, the negative pressure detection value lights up red and is saved to host computer 1. Alternatively, 1) after resolving the fault, reinstall the urea pump for a second test; 2) install a new urea pump and start testing again from step 1; or 3) terminate the test directly. If there are no faults, the negative pressure detection value lights up green, and the negative pressure detection value is saved to host computer 1, and the test proceeds to the next step.

[0093] ②Pressure buildup detection:

[0094] The host computer 1 instructs the control circuit board 2 to control the on-off solenoid valve 12 (normally open valve) to open the urea pump's inlet pipe. At the same time, the host computer 1 instructs the control circuit board 2 to start the infusion motor pump 5 to build pressure. When the pressure sensor 9 detects that the infusion motor pump's output pressure reaches 8.7 bar, the control circuit board 2 adjusts the infusion motor pump's power supply voltage to keep the pressure stable for a preset time of 3 seconds. Then, it determines whether the infusion motor pump's output pressure is stable within the calibrated range of 9±0.3 bar.

[0095] 1) If the infusion motor pump output pressure stabilizes within the calibrated range of 9 ± 0.3 bar, the control circuit board 2 sends the pressure buildup time to the host computer 1 for comparison and storage. If the pressure buildup time exceeds 65 seconds, the host computer 1 will output a pressure buildup timeout, illuminate a red light, and stop testing. The host computer 1 will then save the fault information. 1) After resolving the fault, reinstall the urea pump and conduct a second test; or 2) install a new urea pump and start testing again from step 1; or 3) terminate the test. If the pressure buildup time is ≤ 65 seconds, proceed to the next test.

[0096] 2) If the output pressure of the infusion motor pump cannot stabilize within the calibrated range of 9±0.3 bar, the host computer 1 will illuminate a red light and stop the test, indicating an unstable output pressure fault and storing the instantaneous pressure value. (To allow the urea pump to discharge the urea solution, the host computer 1 sends a retraction signal to the control circuit board 2, which drives the retraction electromagnetic pump to retract the urea solution for a preset time of 10 seconds.) 1) After troubleshooting, reinstall the urea pump and perform a second test; or 2) install a new urea pump and start the test again from step 1; or 3) terminate the test directly. If there are no faults, proceed to the next test.

[0097] Step 7: Urea pump zero injection volume voltage stabilization test

[0098] Go to step 6, that is, after the pressure build-up test of the urea pump 4 passes, at zero injection volume (i.e., the electromagnetic nozzle is closed), the host computer 1 instructs the control circuit board 2 to collect the pressure sensor 9 signal and the infusion motor pump 5 speed signal, and sends the detected pressure signal and motor speed value to the host computer 1, which determines the stability of the output pressure of the urea pump 4 infusion motor pump:

[0099] 1) If the infusion motor pump speed is normal, but the pressure fluctuation exceeds the calibrated range of 9±0.3bar, the host computer 1 lights up red, indicating that the infusion motor pump output pressure exceeds the tolerance fault, stops the test, and the host computer saves the fault information: 1) After troubleshooting, reinstall the urea pump and retest in step 6, or 2) install a new urea pump and start the test from step 1; or 3) end the test directly.

[0100] 2) If the infusion pump motor speed is also outside the normal speed range and the pressure is unstable, the host computer 1 lights red, indicating a one-way return valve failure. Testing stops and the host computer saves the fault information: 1) After troubleshooting, reinstall the urea pump and repeat the test in step 6; or 2) install a new urea pump and start the test again in step 1; or 3) terminate the test immediately.

[0101] 3) If the infusion pump motor speed is within the normal speed range and the pressure fluctuation does not exceed the calibrated range of 9±0.3bar, proceed to the next step of the test.

[0102] Step 8: Urea pump injection accuracy test

[0103] Go to step 7, that is, after the zero injection amount voltage stabilization test of the urea pump is passed, the host computer 1 instructs the control circuit board 2 to control the start of the infusion motor pump 5 to automatically perform 8 unit injection amount tests in sequence (the 8 unit injection amounts are 0, 350, 900, 1800, 2700, 3600, 5400, 6300, and 7200 ml / h, respectively. Of course, the urea pump has at least 3 unit injection amounts within its 0-maximum injection amount range, such as 3 unit injection amounts of 0, 2800 l / h, and the maximum injection amount, or 350, 1800, and 6300 l / h, respectively). After each unit injection amount lasts for 1s (the injection time can be preset), the pressure sensor 9 detects the output pressure fluctuation of the infusion motor pump 5, and uploads the detection data from the control circuit board 2 to the host computer 1. The host computer 1 determines whether the pressure fluctuation in each unit injection amount test exceeds the calibrated 9±0.3 bar range:

[0104] 1) If the pressure fluctuation does not exceed the calibration range, proceed to the next step of testing.

[0105] 2) If the pressure fluctuation exceeds the calibration range, the upper computer 1 lights up red and stops testing. The upper computer 1 stores the fault data in the database of the corresponding test urea pump: 1) After troubleshooting, reinstall the urea pump and retest from step 6, or 2) install a new urea pump and start testing from step 1; or 3) end the test directly.

[0106] Step 9: Check the pumping function of the electromagnetic pump

[0107] Going to step 7, that is, after the urea pump injection accuracy test is passed, the host computer 1 instructs the control circuit board 2 to start the withdrawal electromagnetic pump 6 to withdraw the urea aqueous solution in the urea pump: start the withdrawal electromagnetic pump and open the on-off electromagnetic valve at the same time to withdraw the electromagnetic pump 6 within 60 seconds (the withdrawal time can be preset). During the withdrawal process, the minimum negative pressure signal of the negative pressure sensor 13 is collected and compared with the calibration value of -100 mbar of the host computer 1 (if the negative pressure detection value is less than the calibration value -100 mbar, it is qualified, otherwise it is unqualified):

[0108] 1) If the backflow negative pressure is greater than the calibrated value -100mbar (the reason for the backflow negative pressure being greater than the calibrated value is: failure to start the backflow electromagnetic pump 6 or leakage in the backflow pipeline, etc.), the backflow negative pressure fault occurs, the host computer lights up red, stops testing, and saves the negative pressure value in the database of the corresponding test urea pump on the host computer 1: 1) After troubleshooting, reinstall the urea pump and retest from step 6, or 2) install a new urea pump and start testing from step 1; or 3) end the test directly.

[0109] 2) If the back pressure is less than the calibrated value of -100 mbar, proceed to the next step of testing.

[0110] Step 10: Save the data after the test is completed

[0111] The test database of the urea pumps that passed or failed the test is saved and a test result table is automatically generated.

[0112] In the above test method, there is no requirement for the order of testing of step 1 and step 2. The condition for testing in step 3 is: the testing of step 1 and step 2 has been completed.

[0113] In the above test method, there is no order of testing between step 4 and step 5. The condition for testing in step 6 is: the testing of step 4 and step 5 has been completed.

[0114] The inventive point of the present invention is to calibrate the software parameters in the upper computer and instruct the control circuit board to control the diesel vehicle after-treatment device to perform testing work, which can test the performance of the urea pump such as infusion, injection, thawing, withdrawal and injection accuracy, and can also perform a matching test on the urea pump in the entire diesel vehicle after-treatment device; although the embodiment takes a urea pump composed of an independent infusion motor pump and an independent withdrawal electromagnetic pump as an example, this test system and its test method can also be used to test a urea pump composed of an infusion motor pump and a withdrawal electromagnetic pump combined into one infusion withdrawal gear pump. Here, the claims describe the scope of protection of the present invention, but any variation scheme that includes the inventive points of the present invention and does not deviate from the purpose of the present invention falls within the scope of protection of the present invention.

[0115] Compared with the actual vehicle installation test, the device structure system provided by the present invention is simple, economical and practical, and can complete the functional verification and parameter calibration work of the actual vehicle installation test. It can greatly improve the convenience of the diesel engine after-treatment device test and effectively shorten the development cycle of the urea pump and its components in the diesel vehicle after-treatment device.

Claims

1. A urea pump performance testing system, characterized in that: The invention comprises a host computer (1), a control circuit board (2), a mark collection gun (3) and a test unit; wherein the test unit comprises a urea tank (11) for storing a urea aqueous solution, a urea pump (4) having a urea aqueous solution delivery inlet, a delivery outlet, a redraw outlet and a liquid return port and a barcode, an electromagnetic nozzle (8) with a drive coil, a negative pressure sensor (13) and an on-off electromagnetic valve (12), and a urea aqueous solution pipeline connected therebetween, wherein the negative pressure sensor (13) and the on-off electromagnetic valve (12) are sequentially arranged in series between the delivery inlet and the urea pump (4). On the urea aqueous solution pipeline connected to the urea tank (11), the urea pump (4) withdrawal outlet is directly connected to the urea pump (4) delivery inlet, and the electromagnetic nozzle (8) is connected in series to the urea aqueous solution pipeline connected to the urea pump (4) delivery outlet and the urea tank (11); the urea pump includes an electronic control component and a mechanical component, the host computer is electrically connected to the control circuit board (2) and the mark collection gun (3), respectively, and the control circuit board (2) is electrically connected to the negative pressure sensor (13), the on-off electromagnetic valve (12), the urea pump (4) and the electromagnetic nozzle (8), respectively. The host computer (1) comprises a host, a display, a test system software and a keyboard, and is used to read the data barcode of each urea pump tested and establish a corresponding database; store and run the test system program; transmit the test instruction to the control circuit board (2) through the communication interface, and receive the actual voltage or current signal data detected by the control circuit board (2) on the post-processing device; compare and verify with the corresponding calibration parameters, store the test results, and automatically alarm when a fault occurs during the test, stop the test, and display the fault area; The control circuit board (2) receives the detection instruction of the host computer (1) and converts it into a corresponding voltage or current signal to control the test unit to detect the electromagnetic nozzle coil fault and the urea pump performance; sends the data detected during the test to the host computer (1) via an electrical signal and stores it in a database corresponding to the test urea pump; The marking acquisition gun (3) is used to read the barcode on the test urea pump, which contains the production time, serial number and version of the urea pump, and store the coding information in a newly created urea pump database of the host computer (1); The negative pressure sensor (13) is used to detect the maximum negative pressure value generated by the urea pump (4) when building pressure, and feed back the data detected by the control circuit board (2) to the host computer (1) and store it in the database corresponding to the test urea pump; The on-off solenoid valve (12) is controlled by the upper computer (1) to instruct the control circuit board (2) to control the on-off solenoid valve (12) to control the on and off of the liquid inlet pipeline of the urea pump (4); The electromagnetic nozzle (8) is used to simulate the urea nozzle in the diesel vehicle after-treatment device to spray urea aqueous solution into the exhaust pipe. The urea pump performance includes at least urea pump electronic control component fault detection, urea pump pressure buildup, zero injection volume pressure stabilization, injection accuracy and backflow detection. The mechanical components of the urea pump (4) include an infusion motor pump (5), a backflow electromagnetic pump (6), a filter (7), and a one-way liquid return valve (10); the electronic control components of the urea pump include an infusion motor pump (5), an electromagnet of the backflow electromagnetic pump (6), a pressure sensor (9), an ambient temperature sensor (16), a heating plate (14), and a heating plate temperature sensor (15); the delivery inlet of the urea pump (4), the infusion motor pump (5), the filter (7), and the outlet of the urea pump (4) are sequentially connected through a urea aqueous solution pipeline to form an infusion circuit of the urea pump (4); the backflow electromagnetic pump (6) is connected to the infusion motor pump (5), the filter (7), and the outlet of the urea pump (4) through a urea aqueous solution pipeline. The electromagnetic pump (6) is connected in parallel to both ends of the infusion motor pump (5) through the urea aqueous solution pipeline. The pressure sensor (9) and the one-way liquid return valve (10) are sequentially arranged on the urea aqueous solution pipeline that connects the return port of the urea pump (4) with the urea aqueous solution pipeline between the filter (7) and the delivery outlet of the urea pump (4). The heating plate (14) is arranged on the filter (7) and the urea aqueous solution pipeline in the urea pump (4). The heating plate temperature sensor (15) is arranged on the heating plate (14). The ambient temperature sensor (16) is arranged in the urea pump (4). Wherein, the on-off solenoid valve (12) is a normally open valve.

2. A testing method based on the testing system according to claim 1, characterized in that: The test steps include: Step 1: Electromagnetic nozzle coil detection Turn on the power of the test system, and the host computer (1) instructs the control circuit board (2) to detect the coil of the electromagnetic nozzle (8): If there is a fault of an open circuit or short circuit in the electromagnetic nozzle coil, the control circuit board (2) feeds back the information to the host computer (1), the fault light turns red, and the test system stops the next test. After troubleshooting the electromagnetic nozzle (8), the system is reset on the host computer (1) and the electromagnetic nozzle (8) is retested. If the test passes, the test system proceeds to the next test; If there is no fault in the electromagnetic nozzle coil, proceed to the next step of testing; Step 2: Scan the barcode of urea pump The marking acquisition gun (3) scans the barcode on the test urea pump (4) to identify its information and sends the identified information to the host computer (1). The host computer (1) receives the above information and establishes its database, and stores its subsequent performance test information and its fault information in the test urea pump database marked by this barcode. After the test of the test urea pump is completed, it can be called up for viewing at any time: If the barcode scanning fails, the host computer (1) lights up a red light to alarm: 1) stop the subsequent testing work, eliminate the fault, and re-scan the barcode; or 2) replace the test urea pump of the above test system with another test urea pump and scan the barcode of the test urea pump; or 3) end the test directly; If the barcode is scanned successfully, the host computer (1) receives the scan information and establishes the urea pump database, and proceeds to the next step of detection; Step 3: Urea pump communication test The test system is started on the host computer (1), and the communication protocol of the host computer (1) and the control circuit board (2) performs handshake communication with the urea pump: If the communication test fails, the host computer lights up red and stops the test. The host computer records the fault and saves it in the database of the corresponding urea pump: 1) After troubleshooting, reinstall the urea pump and test again; or 2) install a new urea pump and start the test from step 1; or 3) end the test directly; If the communication test is successful, proceed to the next step of the test; Step 4: Urea pump temperature sensor fault detection The host computer (1) instructs the control circuit board (2) to detect the ambient temperature sensor and the heating plate temperature sensor in the urea pump respectively, and compares the detected temperature signals with the temperature calibration values in the host computer (1) respectively, so as to judge whether the ambient temperature sensor and the heating plate temperature sensor in the urea pump are faulty: if there is a fault in the ambient temperature sensor and the heating plate temperature sensor, the host computer (1) displays the fault type in red and stores the fault information in the database corresponding to the test urea pump, and proceeds to the next step of detection; Step 5: Fault detection of urea pump electronic control components The host computer (1) instructs the control circuit board (2) to detect the resistance values of the electronic control components of the urea pump except the temperature sensor, and compares them with the corresponding resistance values calibrated in the host computer (1) to determine whether the above electronic control components are open or short-circuited: If a fault is detected, the host computer (1) displays the corresponding fault in red, stops the test, and stores the test fault information in the database of the corresponding test urea pump: 1) After troubleshooting, reinstall the urea pump and perform a second test; or 2) install a new urea pump and start the test from step 1; or 3) directly end the test; If there is no fault in the test, proceed to the next step; Step 6: Urea pump pressure buildup test Including negative pressure detection and pressure building detection of the infusion motor pump in the urea pump: ①Negative pressure detection: The host computer (1) instructs the control circuit board (2) to control the on-off solenoid valve (12) to close the liquid inlet pipeline of the urea pump; at the same time, the host computer (1) instructs the control circuit board (2) to control the start of the infusion motor pump to run at 2600 rpm for a preset time, and at a predetermined time during the operation of the infusion motor pump, the negative pressure sensor (13) detects the negative pressure signal of the infusion motor pump, and the control circuit board (2) feeds back the negative pressure signal at this moment to the host computer (1), and compares it with the negative pressure calibration value therein. If the negative pressure detection value is less than the negative pressure calibration value, it is qualified, otherwise it is unqualified: If the test fails, the red light will be on and the negative pressure test value will be saved in the host computer (1): 1) After the fault is resolved, reinstall the urea pump and conduct a second test; or 2) install a new urea pump and start the test from step 1; or 3) end the test directly; If qualified, the green light will be on and the negative pressure test value will be saved in the host computer (1) and the next test will be continued; ②Pressure buildup detection: The upper computer (1) instructs the control circuit board (2) to control the on-off solenoid valve (12) to open the liquid inlet pipeline of the urea pump. At the same time, the upper computer (1) instructs the control circuit board (2) to start the infusion motor pump (5) to build pressure. When the pressure sensor (9) detects that the output pressure of the infusion motor pump reaches 8.7 bar, the control circuit board (2) adjusts the power supply voltage of the infusion motor pump to make the pressure remain stable for a preset time, and then determines whether the output pressure of the infusion motor pump is stable within the pressure calibration range: 1) If the output pressure of the infusion motor pump is stable within the pressure calibration range, the control circuit board (2) sends the pressure building time to the host computer (1) to compare with the pressure building calibration time and store it; if the pressure building time is greater than the pressure building calibration time, the host computer (1) will output a pressure building timeout, turn on a red light, stop the test, and the host computer (1) saves the fault information: 1) After the fault is resolved, reinstall the urea pump for a second test; or 2) install a new urea pump and start the test from step 1; or 3) end the test directly; if the pressure building time is less than or equal to the pressure building calibration time, it is qualified and continues to the next test; 2) If the output pressure of the infusion motor pump cannot be stabilized within the pressure calibration range, the host computer (1) lights up a red light to stop the test, indicating that the output pressure of the infusion motor pump is unstable and stores the instantaneous value of the pressure; in order for the urea pump to discharge the urea aqueous solution, the host computer (1) starts the withdrawal electromagnetic pump through the control circuit board (2) to withdraw the urea aqueous solution for a preset time: 1) After troubleshooting, reinstall the urea pump for a second test; or 2) install a new urea pump and start the test from step 1; or 3) end the test directly; 3) If there is no fault, proceed to the next step of testing; Step 7: Urea pump zero injection volume voltage stabilization test Then, proceed to step 6, i.e., after the pressure build-up test of the urea pump (4) passes, at zero injection volume, the host computer (1) instructs the control circuit board (2) to collect the pressure sensor (9) signal and the infusion motor pump (5) speed signal, and sends the detected pressure signal and motor speed value to the host computer (1), which then determines the stability of the output pressure of the urea pump (4) infusion motor pump: 1) If the infusion motor pump speed is within the normal speed calibration range, but the pressure fluctuation exceeds the pressure calibration range, the host computer (1) lights up the red light, indicating that the infusion motor pump output pressure exceeds the tolerance fault, stops the test, and saves the fault information: 1) After troubleshooting, reinstall the urea pump and retest in step 6, or 2) install a new urea pump and start the test from step 1; or 3) directly end the test; 2) If the infusion motor pump speed is not within the normal speed calibration range and the pressure is unstable, the host computer (1) lights up red, indicating a one-way return valve failure, stops testing, and saves the fault information: 1) After troubleshooting, reinstall the urea pump and retest from step 6, or 2) install a new urea pump and start testing from step 1; or 3) end the test directly; 3) If the infusion pump motor speed is within the normal speed calibration range and the pressure fluctuation does not exceed the pressure calibration range, proceed to the next step of the test; Step 8: Urea pump injection accuracy test Then, step 7 is followed, i.e., after the urea pump zero injection amount pressure stabilization test is passed, the host computer (1) instructs the control circuit board (2) to control the start-up of the infusion motor pump (5) to automatically and sequentially perform at least three unit injection amount tests between the zero injection amount and the maximum injection amount of the urea pump calibrated in the host computer (1). After each unit injection amount lasts for a preset injection time, the pressure sensor (9) detects the output pressure fluctuation of the infusion motor pump (5), and uploads the detection data from the control circuit board (2) to the host computer (1). The host computer (1) judges whether the pressure fluctuation in each unit injection amount test exceeds the pressure fluctuation calibration range: 1) If the pressure fluctuation in each unit injection volume test does not exceed the pressure fluctuation calibration range, proceed to the next test; 2) If the pressure fluctuation during the injection amount detection of each unit exceeds the pressure fluctuation calibration range, the upper computer (1) lights up a red light and stops the detection. The upper computer (1) stores the fault data in the database of the corresponding test urea pump: 1) After troubleshooting, reinstall the urea pump and retest from step 6, or 2) install a new urea pump and start the test from step 1; or 3) directly end the test; Step 9: Urea pump backflow test Then, step 7 is followed. After the urea pump injection accuracy test is passed, the host computer (1) instructs the control circuit board (2) to start the withdrawal electromagnetic pump (6) to withdraw the urea aqueous solution in the urea pump: the withdrawal electromagnetic pump is started and the on-off electromagnetic valve is opened at the same time. The withdrawal electromagnetic pump (6) withdraws within the withdrawal preset time. During the withdrawal process, the minimum negative pressure signal of the negative pressure sensor (13) is collected and compared with the negative pressure calibration value of the host computer (1). If the negative pressure detection value is less than the negative pressure calibration value, it is qualified, otherwise it is unqualified. 1) If the negative pressure detection value is greater than the negative pressure calibration value, it is a backflow negative pressure fault, the host computer lights up a red light, stops the test, and saves the negative pressure detection value in the database of the host computer (1) corresponding to the test urea pump: 1) After troubleshooting, reinstall the urea pump and retest from step 6, or 2) install a new urea pump and start the test from step 1; or 3) end the test directly; 2) If the negative pressure detection value is less than the negative pressure calibration value, the test ends.

3. The testing method according to claim 2, wherein: There is no requirement for the order of testing of step 1 and step 2. The condition for testing step 3 is: the testing of step 1 and step 2 has been completed.

4. The testing method according to claim 2, wherein: There is no order of detection between step 4 and step 5. The condition for performing detection in step 6 is: the detection of step 4 and step 5 has been completed.

5. The testing method according to claim 2, 3 or 4, characterized in that: In step 4, the temperature calibration values of the ambient temperature sensor in the urea pump and the temperature sensor of the heater are determined according to the ambient temperature of the room where the urea pump is tested; In the step 5: the resistance calibration values of the infusion motor pump motor, the return electromagnetic pump electromagnet, the pressure sensor, and the heating plate (14) are respectively their normal resistance values; In step 6: the infusion motor pump runs at 2600 rpm for a preset time of 58 seconds; the negative pressure sensor (13) detects the negative pressure signal of the infusion motor pump at a predetermined time of 50 seconds during the operation of the infusion motor pump, and the negative pressure calibration value at this time is -150 mbar; when the pressure sensor (9) detects that the output pressure of the infusion motor pump reaches 8.7 bar, the control circuit board (2) adjusts the power supply voltage of the infusion motor pump to keep the pressure stable for a preset time of 3 seconds; the output pressure of the infusion motor pump is stable within the pressure calibration range; the pressure build-up calibration time is 65 seconds; and the withdrawal preset time is 10 seconds; In step 7, the pressure is calibrated to a range of 9±0.3 bar, and the normal speed calibration range of the infusion motor pump (5) is 1200-1600 rpm; In step 8, each unit injection amount lasts for a preset injection time, and the output pressure fluctuation calibration range of the infusion motor pump (5) is within the range of 9±0.3 bar; In step 9, the preset time for the electromagnetic pump (6) to withdraw is 60 seconds; the minimum negative pressure calibration value during the withdrawal process is -100 mbar.

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