Online NOx emission monitoring method adaptive to working condition of overall vehicle

Abstract

The invention discloses an online NOx emission monitoring method adaptive to the working condition of an overall vehicle. The online NOx emission monitoring method comprises the following steps: first, taking an environment temperature, an altitude and an engine cooling liquid temperature as enabling conditions for monitoring, performing the second step to the fourth step below when the environment temperature, the altitude and the engine cooling liquid temperature are in a normal working range in OBD (On-Board Diagnostics) laws and regulations simultaneously, and ending online NOx emission monitoring if any one of the conditions of the environment temperature, the altitude and the engine cooling liquid temperature is not in the normal working range in the OBD laws and regulations; second,gridding an emission area; third, calculating the specific emission of the NOx in each unit grid area; and fourth, determining an emission standard exceeding limit value. The online NOx emission monitoring method adaptive to the working condition of the overall vehicle has high stability and robustness; whether the NOx exceeds the OBD laws and regulations or not is judged in a calibration time window; and a fault signal is provided for activating fault indicator and reducing torque after a fault is determined.

Description

technical field [0001] The invention relates to a NOx emission monitoring method, more specifically to an online NOx emission monitoring method adapted to the working conditions of the whole vehicle, and belongs to the technical field of control system design of commercial vehicle diesel engines. Background technique [0002] At present, as the problem of air pollution becomes more and more serious, more and more countries have formulated stricter and stricter regulations on motor vehicle emission pollution. With the upgrading of emission regulations, the requirements of the accompanying on-board diagnostic system (OBD) are more comprehensive, and the OBD limits are becoming more and more stringent; the current regulations have clear limits for NOx emissions. Emissions are monitored in real time. [0003] Chinese invention patent application "A Real-time Online Calculation NOx Emission Monitoring Method" (Application No.: CN201610766581.9) discloses a real-time online calcu...

AI Technical Summary

Problems solved by technology

However, the invention patent application has the following defects: 1. Only use the NOx mass flow rate for calculation, which fails to reflect the emission levels under different power

2. The map under different working conditions is only based on the universal characteristic test of the bench, and the data source is single. However, in the actual vehicle operating range, it is difficult to achieve the ideal temperature of the catalytic converter under the bench working condition; and the catalytic converter temperature is An important factor affecting the fluctuation of NOx emission value, the change of catalyst temperature is positively correlated with the emission of NOx emission value, but due to the hysteresis of chemical reaction, the change of catalyst temperature is far behind the change of NOx emission value; the actual vehicle operation At the same speed and torque, the NOx emission value will fluctuate due to factors such as exhaust temperature, sudden change in working conditions, and aging of the catalytic converter.

Therefore, the diagnostic method of the patent application for the present invention, which adapts to the NOx emission exceeding the standard of the whole vehicle operating condition, poses a great challenge to the robustness and stability.

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