Control method and device for variable valve timing system of Miller cycle engine

Abstract

The invention provides a control method and device for a variable valve timing system of a Miller cycle engine. In the control method, a first VVT MAP taking economical efficiency as a target and a second VVT MAP taking dynamic property as a target are previously demarcated, and when the engine is in a running state under a steady-state working condition, the variable valve timing system is controlled by virtue of the first VVT MAP, and the economical efficiency of the engine is realized; and when the engine is in a running state under a transient accelerated loading working condition, the variable valve timing system is controlled by virtue of the second VVT MAP, and the dynamic property of the engine is realized, and in this way, when the working conditions of the engine are different, the different VVT MAPs are chosen to control the variable valve timing system. Compared with the purpose of realizing the economical efficiency of the engine in the prior art, the control method and device for the variable valve timing system of the Miller cycle engine give consideration to the economical efficiency and the dynamic property of the engine simultaneously, and improves the acceleratedloading capacity under the transient working condition of the engine.

Description

technical field [0001] The present application relates to the technical field of Miller cycle engines, in particular to a control method and device for a variable valve timing system of a Miller cycle engine. Background technique [0002] Compared with the battery as the power source, the gasoline engine as the power source can realize the long-distance driving of the car. [0003] Most of the existing gasoline engines use the Otto cycle, the valve lift and wrap angle are relatively large, resulting in the highest thermal efficiency of the gasoline engine is only 40%, and more than 30% of the energy is taken away by the exhaust, so the Otto cycle gasoline The engine has problems such as large pumping loss and poor economy. [0004] The valve lift and wrap angle of the Miller cycle engine are small, and the engine load is controlled by changing the closing angle of the intake valve, thereby reducing the pumping loss of the engine under partial load, and solving the problem o...

AI Technical Summary

Problems solved by technology

However, in transient conditions, due to the small valve lift and wrap an

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