Study On Low Speed ​​Performance Of New All - Variable Valve Engine

Limited to the urban traffic system development speed and large motor vehicle ownership, city car’s average speed is low, the engine run for a long time in the working condition of low speed. However, due to the traditional engine valve timing and valve lift are fixed the engine low speed performance is poor, so it is very necessary to study on the condition of low speed and search the method for improving engine low speed performance. Fully variable valve technology can make engine valve timing and valve lift continuously change, which has a huge potential to improve the low-speed performance of the engine. Based on a new type of variable valve train which developed by our project group, this paper mainly study the low speed performance of full variable valve timing engine. The specific content includes the following:Firstly, according to geometric construction and the main technical parameters of a valve fixed engine, use AVL Boost software to establish the simulation model of the engine.Using single factor optimization method to optimize the engine intake advance angle,intake lag angle, exhaust advance angle, exhaust lag angle, intake valve lift value respectively. Use power, fuel consumption rate and the residual gas coefficient as the main evaluation index to determine the comparatively ideal valve timing and valve lift of different speed at low speed condition.Secondly, establish the AVL Boost numerical simulation model of the new type fully variable valve engine. Use the obtained comparatively ideal valve timing and lift parameters as the new type fully variable valve engine low speed control targets. Make simulation to the model and study the low speed performance of the new type fully variable valve engine.Finally, Using engine performance experimental platform to study the experimental performance of engine low speed condition.