CN-121976870-A - Online fault subsection positioning system and method for vehicle-mounted urea injection system

CN121976870ACN 121976870 ACN121976870 ACN 121976870ACN-121976870-A

Abstract

The invention relates to the technical field of engine tail gas aftertreatment, and discloses an online fault sectional positioning system and method of a vehicle-mounted urea injection system, wherein a vehicle-mounted urea box is connected to a first interface of a three-way two-position double-connected electromagnetic valve through a liquid return pipe and a liquid suction pipe, a urea pump is connected to a second interface of the three-way two-position double-connected electromagnetic valve, the three-way two-position duplex electromagnetic valve is characterized in that a quick-change connector is connected to a third interface of the three-way two-position duplex electromagnetic valve, the quick-change connector can be connected with a standby urea box through a pipeline, a urea pump is connected to a urea nozzle through an injection pipe, a first sensor group is arranged in the vehicle-mounted urea box, and a second sensor group is arranged on the urea pump. The invention realizes the rapid distinction of high/low voltage sections, greatly shortens the manual diagnosis time, provides a standardized troubleshooting flow, avoids missing key fault points, reduces the misjudgment rate of on-site maintenance, greatly improves the maintenance efficiency, and reduces the lazy nature of after-sale service to the experience of maintenance personnel.

Inventors

LIU JUN
KANG HAOHAO
YANG SHUN
JI XIANSHENG
REN HONGYUN
CHEN YONG
LING JIANQUN
JI LIWEI

Assignees

上海新动力汽车科技股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260317

Claims (8)

1. The utility model provides an on-line fault segmentation positioning system of on-vehicle urea injection system, its characterized in that, including on-vehicle urea case (1), urea pump (2), urea nozzle (3), reserve urea case (4), automatically controlled ECU (5) and tee bend two-position double solenoid valve (9), on-vehicle urea case (1) are connected to the first interface of tee bend two-position double solenoid valve (9) through liquid return pipe (6) and pipette (7), urea pump (2) are connected to the second interface of tee bend two-position double solenoid valve (9), be connected with quick change joint on the third interface of tee bend two-position double solenoid valve (9), quick change joint accessible pipeline is connected with reserve urea case (4), urea pump (2) are connected to urea nozzle (3) through injection pipe (8), be equipped with first sensor group in on-vehicle urea case (1), be equipped with the second sensor group on urea pump (2), first sensor group, urea pump (2) and tee bend two-position double solenoid valve (9) all with automatically controlled ECU (5).
2. The on-line fault sectionalized positioning system of the vehicle-mounted urea injection system according to claim 1, wherein a filter screen is arranged in the vehicle-mounted urea tank (1), and the first sensor group comprises a differential pressure sensor (10) arranged at two sides of the filter screen, a turbidity sensor (11) arranged in the vehicle-mounted urea tank, a first pressure sensor (14) arranged in the vehicle-mounted urea tank and a flowmeter (12) arranged on the liquid return pipe (6) and the liquid suction pipe (7).
3. The on-line fault staging system of a vehicle urea injection system according to claim 2, characterized in that the second sensor group comprises a second pressure sensor (13) arranged at the inlet of the urea pump (2).
4. An on-line fault sectional positioning method of a vehicle-mounted urea injection system, using the on-line fault sectional positioning system of the vehicle-mounted urea injection system according to claim 3, comprising the steps of: S1, an electronic control ECU (5) monitors the working pressure of the urea pump (2) after the pressure is successfully built, and if the pressure is continuously lower than a preset threshold value and the duration exceeds a set duration, an initial pressure low fault is triggered; s2, after the low fault of the initial pressure is triggered, a quick-change connector on a third interface of the three-way two-position double electromagnetic valve (9) is connected with the standby urea tank (4), and the urea pump (2) is switched to be communicated with the standby urea tank (4); s3, an electronic control ECU (5) monitors the pressure of the urea pump (2), if the initial pressure is low and the fault still exists, the fault is judged to exist in the high-pressure section, and the fault is transferred into a fault checking flow of the high-pressure section; S4, if the fault of low initial pressure disappears, controlling a three-way two-position double electromagnetic valve (9) to switch the urea pump (2) to be communicated with the vehicle-mounted urea tank (1); S5, the electronic control ECU (5) monitors the pressure of the urea pump (2) again, if the initial pressure is low and a fault occurs, the fault is judged to exist in the low-pressure section, the fault is transferred to a fault detection flow of the low-pressure section, and if the fault is not triggered again, the fault is judged to be a temporary fault or a false report and a fault record is cleared.
5. The online fault sectionalized positioning method of the vehicle-mounted urea injection system according to claim 4, wherein the high-pressure section comprises a urea pump (2) and a urea nozzle (3), and the low-pressure section comprises a vehicle-mounted urea tank (1) and a connecting pipeline between the vehicle-mounted urea tank and the urea pump (2).
6. The on-line fault location method for an on-board urea injection system of claim 4, wherein the condition in step S1 that triggers the initial low pressure fault is that the urea pump (2) pressure is continuously below a first pressure threshold and the duration exceeds a first time period threshold or that the urea pump (2) pressure is continuously below a second pressure threshold and the duration exceeds a second time period threshold; wherein the first pressure threshold is greater than the second pressure threshold and the first time period threshold is greater than the second time period threshold.
7. The method for on-line fault localization of a vehicle urea injection system according to claim 4, wherein the high-pressure section fault localization procedure in step S3 comprises: s31, performing a single test of the urea pump (2), controlling the urea pump (2) to run under a specific duty ratio, detecting the pressure of a liquid suction port of the urea pump (2), comparing the pressure with a model value, and reporting the fault of the liquid suction port of the urea pump (2) if the deviation exceeds a range; S32, analyzing a pressure-duty ratio characteristic curve of the urea pump (2), and if the pressure-duty ratio characteristic curve deviates from a standard curve, reporting a mechanical fault of the urea pump (2); s33, analyzing the pressure pulsation characteristic during urea injection, and if the pulsation waveform is abnormal, reporting that the urea nozzle (3) is blocked or leaked.
8. The method for on-line fault localization of a vehicle urea injection system according to claim 4, wherein the low-pressure section fault localization procedure in step S5 comprises: s51, monitoring the pressure difference of the front and rear of a filter screen in the vehicle-mounted urea box (1) through a pressure difference sensor (10), and if the pressure difference value exceeds a preset threshold value, reporting a filter screen blocking fault; s52, monitoring the turbidity of the urea solution in the vehicle-mounted urea box (1) through a turbidity sensor (11), and if the turbidity exceeds a threshold value or shows an ascending trend, reporting a urea solution pollution early warning fault; S53, monitoring the pressure in the vehicle-mounted urea box (1) through a first pressure sensor (14), and if the pressure is abnormally higher than an ambient pressure threshold value, reporting a blockage fault of a ventilation part of the vehicle-mounted urea box (1); And S54, monitoring the flow of the urea solution in the liquid suction pipe (7) through a flowmeter (12), and if the flow is different from a normal range, reporting a pipeline blockage or leakage fault.

Description

Online fault subsection positioning system and method for vehicle-mounted urea injection system Technical Field The invention relates to the technical field of engine tail gas aftertreatment, in particular to an online fault subsection positioning system and method of a vehicle-mounted urea injection system. Background The urea injection system is a core component of a diesel SCR (selective catalytic reduction) system, and the pressure stability of the urea injection system directly determines the atomization effect and the NOx conversion efficiency of the urea solution. In the prior art, the pressure abnormality is usually judged by a pressure sensor for threshold value, but a systematic fault positioning method is lacked, so that the maintenance efficiency is low and the error piece rate is high. Particularly, when the system has a composite fault that the pressure is continuously lower than a threshold value after pressure establishment, the traditional method is difficult to rapidly distinguish fault responsibility areas of a low-pressure section (urea tank to pump inlet) and a high-pressure section (pump to nozzle). Disclosure of Invention The invention aims to solve the technical problem that a specific fault interval is difficult to locate when the existing urea injection system is abnormal. In order to solve the technical problems, the technical scheme of the invention provides an online fault sectionalized positioning system of a vehicle-mounted urea injection system, which comprises a vehicle-mounted urea box, a urea pump, a urea nozzle, a standby urea box, an electric control ECU (electronic control Unit) and a three-way two-position double electromagnetic valve, wherein the vehicle-mounted urea box is connected to a first interface of the three-way two-position double electromagnetic valve through a liquid return pipe and a liquid suction pipe, the urea pump is connected to a second interface of the three-way two-position double electromagnetic valve, a third interface of the three-way two-position double electromagnetic valve is connected with a quick-change connector, the quick-change connector can be connected with the standby urea box through a pipeline, the urea pump is connected to the urea nozzle through an injection pipe, a first sensor group is arranged in the vehicle-mounted urea box, a second sensor group is arranged on the urea pump, and the first sensor group, the second sensor group, the urea pump and the three-way two-position double electromagnetic valve are electrically connected with the electric control ECU. Optionally, the on-vehicle urea incasement is equipped with the filter screen, first sensor group is including locating the differential pressure sensor of filter screen both sides, locating the turbidity sensor in the on-vehicle urea case, locating the first pressure sensor in the on-vehicle urea case and locating the flowmeter on liquid return pipe and the pipette. Optionally, the second sensor group includes a second pressure sensor disposed at an inlet of the urea pump. An online fault sectional positioning method of a vehicle-mounted urea injection system comprises the following steps: S1, an electronic control ECU monitors working pressure after the urea pump is successfully built, and if the pressure is continuously lower than a preset threshold value and the duration exceeds a set duration, an initial pressure low fault is triggered; S2, after the low fault of the initial pressure is triggered, a quick-change connector on a third interface of the three-way two-position double electromagnetic valve is connected with a standby urea tank, and the urea pump is switched to be communicated with the standby urea tank; s3, the electronic control ECU monitors the pressure of the urea pump, if the fault still exists due to low initial pressure, the fault is judged to exist in the high-pressure section, and the fault is transferred into a fault checking flow of the high-pressure section; S4, if the fault of low initial pressure disappears, controlling a three-way two-position double electromagnetic valve to switch the urea pump to be communicated with the vehicle-mounted urea box; S5, the electronic control ECU monitors the pressure of the urea pump again, if the initial pressure is low and a fault occurs, the fault is judged to exist in the low-pressure section, the fault is transferred to a fault checking flow of the low-pressure section, and if the fault is not triggered again, the fault is judged to be a temporary fault or misinformation and the fault record is cleared. Optionally, the high-pressure section comprises a urea pump and a urea nozzle, and the low-pressure section comprises a vehicle-mounted urea tank and a connecting pipeline between the vehicle-mounted urea tank and the urea pump. Optionally, the condition triggering the initial low pressure fault in step S1 is that the urea pump pressure is continuously below a first pressure threshold and the duration exce