A method and system for controlling fuel injection at cold start-up of an in-cylinder direct-injection gasoline engine

Abstract

The invention discloses a cold-start oil injection control method and a cold-start oil injection control system of a direct-injection gasoline engine, wherein the cold-start oil injection control method of the direct-injection gasoline engine comprises the following steps: acquiring an oil track pressure mode during cold start; injecting oil according to a first oil injection quantity if the oil track pressure mode is a low-pressure mode; otherwise, injecting the oil according to a second oil injection quantity, wherein the first oil injection quantity is larger than the second oil injection quantity. According to the method and the system disclosed by the invention, when the oil track pressure is in the low-pressure mode, an enough oil atomization quantity can be generated inside a cylinder so as to form ignitable mixed gas, so the gasoline engine can be started conveniently. When the oil track pressure is in a normal mode, formation of over-dense mixed gas can be weakened, so emission of tail gas particles can be reduced.

Description

technical field [0001] The invention relates to the technical field of automobiles, in particular to a method and system for controlling fuel injection at cold start of an in-cylinder direct injection gasoline engine. Background technique [0002] In recent years, as energy and environmental issues have become increasingly severe, countries have enacted strict restrictive laws and regulations on automobile energy conservation and emission reduction, which has brought strong pressure to major automobile companies. [0003] Gasoline Direct Injection (GDI) engine has been widely recognized and popularized around the world for its remarkable advantages of high power, low fuel consumption and low emission. Almost all series of Volkswagen models are equipped with TSI direct injection engine, as well as other joint venture vehicles Enterprises are also gradually promoting the application of GDI engines in the models they sell. Based on the characteristics of the development of pas...

AI Technical Summary

Problems solved by technology

[0006] (1) For the cold engine start process, the existing technology only controls the fuel injection quantity according to the current engine speed and engine water temperature, that is, the system only controls the fuel injection quantity during the cold engine start process according to the engine speed and cooling water temperature. When the pressure is low, the fuel atomization becomes worse. In order to ensure the successful start of the cold engine, more fuel must be injected so as to form an ignitable mixture. However, the more fuel injected, the easier it is for the cylinder to Partially rich mixture occurs. As mentioned above, the locally overrich mixture will produce a large amount of particulate matter during the combustion process of the cold engine, which will lead to the deterioration of particulate matter emissions.

[0007] (2) For the cold engine running stage, the existing technology adopts the control strategy that all fuel is injected in the intake stroke. Since the fuel is injected in the intake stroke, the piston is in the downward process, and the injected fuel is very likely to be on the cold cylinder wall. Fuel droplets are formed on the cylinder wall, and the phenomenon of wet wall is obvious. The fuel droplets on the cylinder wall will not burn completely during the combustion process, and a large amount of particulate matter will also be generated, which is not conducive to the control of particulate matter emission

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