HCCI (homogeneous charge compression ignition) engine fire detecting and controlling method

Abstract

An HCCI (homogeneous charge compression ignition) engine fire detecting and controlling method includes that a crank angle signal and a cylinder pressure signal are acquired in each working cycle of an HCCI engine, a pressure observation window with a compression top dead center is arranged, the integral value of the cylinder pressure signal in the pressure observation window is compared with a fire pressure threshold value at a finishing point of the pressure observation window, when the integral value is smaller than or equal to the fire pressure threshold value, an ECU (electronic control unit) sequentially transmits an oil recharging signal and an ignition signal to an oil injector and an ignition coil, and mixed gas in a fire cylinder is ignited in an expansion stroke. The HCCI engine fire detecting and controlling method has the advantages of simplicity, reliability, high control precision and the like, inter-circulation fluctuation of the HCCI engine can be reduced effectively, stability of combustion of a small load is improved, a running range of an HCCI combustion mode is expanded, fuel economy is improved, and HC (hydrocarbon compound) emission caused by fire is reduced.

Description

technical field [0001] The invention relates to a method for detecting and controlling the combustion state of an in-cylinder direct-injection gasoline HCCI engine, which belongs to the technical field of engines. Background technique [0002] In order to meet the severe challenges of energy saving and environmental protection, the international internal combustion engine industry has carried out extensive research on new combustion technologies for internal combustion engines in recent years. Among them, the homogeneous charge compression combustion technology (HCCI) has become the most important technology due to its outstanding fuel-saving performance and low emission performance. One of the research hotspots. However, HCCI combustion is controlled by chemical reaction kinetics and is very sensitive to factors such as the temperature, concentration and composition of the mixture. Especially in the light load state, the heat generated by the working fluid per unit cycle i...

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Problems solved by technology

[0003] Reliable detection of engine misfire is an important prerequisite for controlling the combustion state of the engine. At present, some people use the engine speed or ion current as the basis for judging the misfire state. It is easy to fail when driving on the road; when the ion current signal is used to judge the HCCI engine misfire, because the HCCI mixture is relatively thin under light load, the ion current signal is weak, the signal-to-noise ratio is poor, and the signal feature extraction is difficult, so it is difficult to realize industrial application

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