| Summary: | 碩士 === 遠東技術學院 === 機械研究所 === 94 === Intake efficiency is the most fundamental and important parameter for engine performance, yet the open and close timing as well as the lift depth of the intake valves are determined by the contour curve of the camshaft, that means the valve timing and lift depth are constant and fixed.
With the rising of environment-consciousness and the economy costs concerns, the developments of high horse power and low fuel consumption engine are the ultimate goal for every car manufacturer. By understanding the development and function of the variable valve timing and lift, we realized that four-stroke engine can get much better volumetric efficiency by tuning open and close angles of the intake valves.
This paper is based on the model of TOYOTA 1.8 Celica GT-S ,After re-modification, the Compound camshaft can change the contour curve of the camshaft, single-cam alone may have a varied close and open timing and lift depth, it’s a Compound camshaft with continuous variable valve timing and lift.
Analysis and evaluation of this cam for its velocity and acceleration under different revolutions revealed the cam redesigned will trigger some mechanical drive problems, further modifications are still required.
Based on the analysis, the continuous curve won’t cause jumping which has no difficulty analytically and pragmatically, the control system of this mechanism may well be used on the engine practically through experiments.
|
|---|
