Method and device for reducing engine exhaust emissions

Abstract

The invention discloses a method for reducing engine exhaust emissions. The method is applied to an EMS system and comprises the steps that the running state of an engine and the driving state of a vehicle are detected, and when the running state of the engine represents that the engine is in an idling state and the driving state of the vehicle represents that the vehicle is in a stop state, the emission reducing strategy used for discharging residual gas pollutants in the engine is started. The method for reducing engine exhaust emissions focuses on reducing of gas pollutants left in a cylinder when the engine is shut down, the advantages that after shutdown, the temperature of three-way catalysts is high and catalytic conversion can still be effectively carried out are fully utilized, residual gas pollutants in the engine cylinder are discharged out immediately in a harmless gas manner, then the situation that a large amount of harmful gas is discharged when cold start of the vehicleis achieved again is effectively avoided, and meanwhile the phenomenon of oil dilution of the engine can be reduced easily.

Description

technical field [0001] The present application relates to the technical field of internal combustion engines, in particular to a method and device for reducing engine exhaust emissions. Background technique [0002] During the cold start and warm-up process of the gasoline engine, the throttle valve of the engine usually opens relatively small. It is difficult to fully mix with air to form a uniform combustible mixture. At the same time, the concentration of residual exhaust gas in the engine cylinder is high, and the temperature of the combustion chamber is low. Without generating enough combustible mixture, the engine cannot burn stably, that is, abnormal combustion occurs, and a large amount of unintended combustion occurs. Harmful gases that are completely combusted, and the exhaust temperature at this time has not reached the light-off temperature of the three-way catalyst installed on the vehicle exhaust system, so the three-way catalyst cannot effectively function, t...

AI Technical Summary

Problems solved by technology

Although these methods play a certain role in reducing exhaust emissions during cold start, because catalyst electric heating, air preheating and other methods need to add additional heating parts, therefore, it will correspondingly lead to the cost of vehicle manufacturing increases, but also reduces the reliability of the vehicle

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