Combustion system of gasoline direct injection engine and control method thereof

Abstract

The invention provides a combustion system of a gasoline direct injection engine and a control method thereof, for improving the combustion and discharge status of a cold starting stage. The combustion system of the gasoline direct injection engine comprises a cylinder cover, a piston, a cylinder sleeve, a spark plug and an oil injector; the cylinder cover is provided with an intake valve, an exhaust valve, an intake passage connected with the intake valve, and an exhaust passage connected with the exhaust valve; the top surface of the piston is provided with an intake valve evading pit corresponding to the position of the intake valve and an exhaust valve evading pit corresponding to the position of the exhaust valve; the spark plug is mounted on one side of the cylinder cover between the intake valve and the exhaust valve and is close to the exhaust valve, the top surface of the piston rod between the downside of the spark plug and the oil sprayer is hollowed to form a concave pit, and the oil injector is arranged under the intake valve and faces towards the concave pit. The control method of the combustion system comprises the steps: A, a twice-injection layered combustion manner is adopted under a cold starting condition; and B, and a single-injection homogeneous equivalence-ratio combustion manner in which gasoline is injected one time in a gas inlet stroke is adopted under the other conditions.

Description

technical field [0001] The invention belongs to the technical field of automobile engine manufacture, and in particular relates to a combustion system of an in-cylinder direct-injection gasoline engine and a control method thereof. Background technique [0002] With the increasingly serious environmental problems and the rapid increase of car ownership, the relevant regulations on energy saving and emission reduction of cars have become more stringent. Compared with the traditional port injection gasoline engine (PFI), gasoline direct injection (GDI) has better economic and emission performance, and has become the main development direction and research focus of gasoline engines. [0003] In recent years, the fuel economy of gasoline engines has been greatly improved through research on new lean combustion modes represented by stratified lean combustion in-cylinder direct injection gasoline engines and homogeneous compression ignition gasoline engines. The utilization of th...

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Problems solved by technology

However, this kind of GDI with the goal of lean burn has also encountered some problems in practical application: the required lean burn catalyst is not yet mature, resulting in high NOx emissions, and it is very difficult to control the stratified lean burn mixture. high hydrocarbon

In terms of emissions, due to the homogeneous equivalent ratio, the traditional three-way catalyst can still be used, and the feasibility of industrialization is high. The GDI technology can more accurately control the fuel injection amount and the oil-gas mixing process in the cylinder, and has a greater reduction in cold start. HC emission potential, but some studies have also shown that the unburned hydrocarbon emissions account for 60% to 80% of the total emissions during the cold start and warm-up process of the homogeneous equivalent ratio direct injection gasoline engine, which directly affects whether the engine can meet the more stringent requirements. Emission regulations, cold start emissions have therefore become the focus and difficulty of today's automotive emission control technology research

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