A fault diagnosis method for scr urea injection device
A technology of urea injection and fault diagnosis, which is applied to the diagnosis device of the exhaust gas treatment device, the electronic control of the exhaust gas treatment device, and the exhaust device, etc. question
Active Publication Date: 2021-04-02
SHANGHAI XINGRONG AUTOMOBILE TECH CO LTD
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Problems solved by technology
[0006] However, if there are problems such as urea pump aging and liquid inlet filter blockage in the SCR urea injection device, it will be more difficult for the urea pump to replenish the pressure in the liquid outlet pipe, which will make it more difficult to replenish the liquid outlet pipe in time after the nozzle is opened. The pressure of the urea solution leads to more obvious pressure fluctuations, and the resulting imbalance and instability of the urea solution will also affect the operation of the SCR after-treatment system, reduce the efficiency of vehicle operation, and may also affect the safety of driving. Safety and stability will be affected, and driving safety will be endangered
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Embodiment 1
[0049] For the urea injection device of the SCR system of a diesel vehicle, the fault diagnosis is carried out during the injection stage:
[0050] Such as figure 1 Shown:
[0051] S1: Real-time acquisition of the pressure value P of the urea solution in the outlet pipe of the device;
[0052] S2: Define the detection cycle T=1s, and divide a detection cycle T into n (n=100) time intervals t in time sequence i (t 1 , t 2 ......t 100 ), the duration of each time interval is 10ms;
[0053] The initial cumulative value C of abnormal situations is set to zero (C=0);
[0054] The standard quartile difference △P0=35kpa and the threshold C of the cumulative value of abnormal situations are determined in advance through simulation analysis in the laboratory max = 3;
[0055] S3: Sequentially pair the time interval t i Draw a box plot and its corresponding urea solution pressure value P, and extract the upper quartile P in the box plot 1 with lower quartile P 3 , calculate t...
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The invention relates to a fault diagnosis method for an SCR urea injection device, which belongs to the technical field of on-board equipment detection; when the car is running, the method can monitor and extract the basis of the pressure of the urea solution in the outlet pipe of the SCR urea injection device in real time In real time, the difference between the quartile difference of the urea solution pressure and the standard quartile difference in a certain detection period is compared in real time. Through scientific statistical methods, real-time fault diagnosis of the SCR urea injection device can be realized, and it can be detected in the fault state In this case, the diagnosis result will be prompted to the driver in time to prevent the safety and stability of driving from being affected by the unbalanced discharge of urea solution and unstable pressure.
Description
technical field [0001] The invention relates to a fault diagnosis method for an SCR urea injection device, and belongs to the technical field of vehicle-mounted equipment detection. Background technique [0002] With the continuous development and growth of my country's automobile industry, the market share of commercial vehicles is also constantly increasing. As the main power source of commercial vehicles, diesel engines are also increasing year by year in terms of demand and delivery. While diesel engines have sufficient displacement, excellent power, and excellent fuel economy, their pollution to the environment is also high, which has become an urgent problem to be solved in my country's vehicle emission control. National VI emission standards are implemented for heavy-duty diesel engines within a certain range. In order to achieve the purpose of reducing pollution during the working process of diesel engines, SCR (Selective Catalytic Reduction, Selective Reduction Catal...
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IPC IPC(8): F01N11/00F01N3/20
CPCF01N11/00F01N3/2066F01N2610/02F01N2610/148Y02T10/40Y02T10/12
Inventor 陈一平何家明蔡继业
Owner SHANGHAI XINGRONG AUTOMOBILE TECH CO LTD