Cold start warm-up control method and device

Abstract

The embodiment of the invention provides a cold start warm-up control method and device. The method comprises the steps that in the cold start process of an engine, by turning off a supercharger and adjusting the opening degree of an air inlet throttle valve to a minimum opening degree value to reduce the air inflow, the quick warm-up of the engine is achieved quickly, and the exhaust temperaturedemands of after-treatment are met; and meanwhile, when the in-cylinder pressure does not meet the preset negative pressure threshold value, by calibrating the valve timing to make the in-cylinder pressure meet the preset negative pressure threshold value and controlling the fuel injection advance angle to be advanced by a certain angle, fuel can be sufficiently premixed, the combustion stabilityis guaranteed, the engine can be in a premixed charge compression ignition (PCCI) mode, and therefore, emission of oxynitride NOx and particulates PM during cold start of the engine is reduced.

Description

technical field [0001] Embodiments of the present invention relate to the technical field of engines, and in particular to a method and device for controlling cold start and warm up. Background technique [0002] In order to meet the emission requirements of diesel engines, it is necessary to quickly raise the exhaust temperature of the after-treatment system of the cold-started engine to a certain temperature, so that the after-treatment system can reach the best working conditions, which is called "warming up". [0003] At present, the warm-up method commonly used in the prior art to increase the exhaust temperature is to reduce the intake air flow by controlling the intake throttle valve, thereby increasing the exhaust temperature. [0004] However, increasing the exhaust temperature by controlling the intake throttle valve will cause insufficient combustion of diesel oil, resulting in deterioration of exhaust gas, which cannot meet environmental protection requirements. ...

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Problems solved by technology

[0005] The embodiment of the present invention provides a cold start warm-up control method and device to solve the problem that in the prior art, increasing the exhaust temperature by controlling the air intake throttle valve will cause insufficient combustion of diesel oil, resulting in deterioration of exhaust gas, which cannot meet environmental protection requirements The problem

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