Method and device for emission monitoring and control of obd system

Abstract

The invention provides an emission monitoring and controlling method and device of an OBD system. The method comprises the steps of obtaining the current state of the emission monitoring release condition of oxynitrides, wherein the emission monitoring release condition of the oxynitrides at least comprises working state parameters of an engine; judging whether the current state of the emission monitoring release condition of the oxynitrides reaches the emission monitoring release index of the oxynitrides or not, wherein the monitoring release index at least comprises a stable index of the engine; if the current state of the emission monitoring release condition of the oxynitrides reaches the emission monitoring release index of the oxynitrides, calculating the current actual conversion efficiency of the oxynitrides; judging whether the actual conversion efficiency is not larger than the minimum threshold of the marked conversion efficiency of the oxynitrides or not, and if the actual conversion efficiency is not larger than the minimum threshold of the marked conversion efficiency of the oxynitrides, giving an alarm to prompt that the emission of the oxynitrides exceeds the standard. According to the monitoring and controlling method and device, the defect that in the prior art, due to the fact that when the engine is in the non-stable state, the emission can not reach the standard, a false alarm is given is overcome, and the alarm accuracy rate of the emission monitoring release of the OBD system is improved.

Description

technical field [0001] The invention relates to the technical field of engine exhaust gas treatment, in particular to an emission monitoring and control method and device for an OBD system. Background technique [0002] In order to meet the requirements of OBD emission regulations, the OBD system should have the function of monitoring the working efficiency of the nitrogen oxide compound (DeNOx) system. In the existing national IV diesel engine SCR technology route, the NOx content downstream of the SCR box is monitored in real time through the nitrogen oxide NOx sensor downstream of the SCR box, and the conversion efficiency of the SCR box is calculated to monitor the working efficiency of the SCR system. [0003] In the OBD system of the existing SCR technical route, the influence of the state of the engine on the nitrogen oxide emission is not considered in the monitoring and control method of nitrogen oxide emission. However, during the actual driving process of the veh...

AI Technical Summary

Problems solved by technology

Therefore, it may cause the conversion efficiency of nitrogen oxides to fail to meet the standard when the engine is in an unsteady state

[0004] In the emission monitoring of the existing OBD system, because the influence of the state of the engine on the emission is not considered, no matter what state the engine is in, as long as the monitoring release index is met, the emission will be monitored, and when the emission is not When the standard is reached, report an error

However, the existing monitoring release conditions are all calibrated when the engine is in a steady state

Therefore, when the engine is in an unsteady state, the existing emission monitoring and control method of the OBD system may cause the risk of false reporting by the nitrogen oxide emission monitoring system due to the emission not meeting the standard, thereby affecting the normal operation of the vehicle.

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