An optimized control method for obd monitoring of plug and play urea injection system

Abstract

The invention provides an optimal control method of plug-and-play urea injection system OBD monitoring. The optimal control method of plug-and-play urea injection system OBD monitoring comprises the steps that under the condition that the plug-and-play system cannot receive the work state of a pump or process pumping pressure, through correction of fault code information of a DCU end and a trigger requirement of an ECU end, a SPN1 is additionally arranged, the definitely diagnosed fault that the urea pump is not in the injection state and the system always tries voltage buildup is processed into the measure that irrelevant lamp turning on is conducted and an ECU is triggered not to conduct efficiency diagnosis, the other SPN2 is additionally arranged to process the fault that the urea pump breaks down, stops and limits torque after 50 hours into the measure that relevant lamp turning on is conducted, and the ECU is triggered not to conduct efficiency diagnosis, and then requirements of laws and regulations are better met.

Description

technical field [0001] The invention belongs to the technical field of engines, and in particular relates to the technical field of engine exhaust post-treatment. Background technique [0002] At present, the most mainstream after-treatment technology for diesel engine exhaust is selective catalytic reduction technology (SCR). The main principle of SCR technology is to spray urea into the exhaust gas. reaction, reducing it to environmentally friendly nitrogen. [0003] The SCR injection system is a key component used in diesel engine emission upgrades. Whether the OBD monitoring of the SCR injection system meets the requirements of the regulations and can accurately determine the fault is the premise to ensure that the fault inspection of the SCR injection system is normal. [0004] For non-plug-and-play OBD monitoring, the flag position of the normal ECU passing the efficiency diagnosis is 1 (FID, function identifier), and the conditional diagnosis is performed, and the ef...

AI Technical Summary

Problems solved by technology

[0006] (1) When the urea pump fails and the pump stops, but the fault level is torque limit after 50 hours, the ECU is still performing efficiency diagnosis, and the fault of super five and super seven will be reported before the pump stop fault, resulting in engine torque limit , which is not in compliance with the regulatory requirements;

[0007] (2) When the urea pump is in the fault diagnosis process, if the pipeline is being heated, the attempt to build pressure is unsuccessful, and the trial process is continued, although the ECU end has a request for injection volume, the DCU end will not execute it, and the efficiency diagnosis is still being performed at this time , Super five and super seven faults may also be reported, resulting in engine torque limitation, which also does not meet the requirements of regulations, and it is easy to cause frequent torque limitation, causing customer dissatisfaction

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