Atkinson cycle engine air-fuel ratio control system

Abstract

The invention relates to an Atkinson cycle engine air-fuel ratio control system in the technical field of automobile engines, which comprises an engine electric control unit, an inlet reflow estimation unit, a residual gas estimation unit, an engine rotating speed sensor, a throttle position sensor, a cam shaft position sensor, an oxygen sensor and a fuel sprayer, wherein the engine electric control unit, the inlet reflow estimation unit, the residual gas estimation unit and an engine air-fuel ratio feedforward controller are connected through a controller area network (CAN) bus; and the engine rotating speed sensor, the throttle position sensor and the cam shaft position sensor are connected with the engine electric control unit through a signal wire. The invention combines the air-fuel ratio feedforward control and the air-fuel ration feedback control, determines the fuel spraying amount in real time according to different inlet reflow amount and residual gas amount in a cylinder, improves the accuracy and the transient response characteristic of the air-fuel ratio control, and effectively improves the economy and the exhaust performance of the engine.

Description

technical field [0001] The invention relates to a device in the technical field of automobile engines, in particular to an Atkinson cycle engine air-fuel ratio control system. Background technique [0002] The concept of the Atkinson cycle engine was proposed early in the 1880s. In the Atkinson cycle, the actual expansion ratio is greater than the actual compression ratio, the proportion of heat energy converted into mechanical energy is large, and the power stroke is long; the effective displacement of the engine is adjusted according to the load of the engine by using the closing timing of the intake valve, and the throttle valve is fully opened or Wide open greatly reduces engine pumping losses at part load and improves fuel economy. However, although the Atkinson cycle engine has the characteristics of high thermal efficiency, it has the problem of low power. Therefore, in the era of pursuing power in the past, the research of Atkinson cycle engine was ignored by peopl...

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Problems solved by technology

[0004] After searching the prior art, it was found that the Chinese patent application of Chinese Patent Document No. CN1755084 describes an engine air-fuel ratio control system, which uses the oxygen sensor air-fuel ratio feedback control to perform precise control of the air-fuel ratio. .But this patent does not consider the residual exhaust gas in the cylinder and the engine intake air recirculation, and there is no air-fuel ratio feed-forward controller, and the transient response of air-fuel ratio control is slow

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