配气机构改进的必要性和方法

Methods and necessities of improving valve mechanism

现有四冲程往复活塞式内燃机上采用的气门式配气机构,制约了该内燃机节能减排水平的进一步提高:1.汽油机中,气门式配气机构向内往复开闭,使气门头向内伸出占用了缸内空间,导致缸内废气无法完全排出。在怠速、低速时,为了克服残余废气的稀释作用,需加浓混合气,造成C O的大量生成;2.柴油机中,气门式配气机构的气门头对进气气流有阻碍作用,使充量系数和进气流速成反比,为保证充量系数而降低进气流速,导致缸内气体运动强度不够、油气混合不均匀,实际运转时造成C O、PM、N Ox的大量生成。为解决上述问题,本人设计了旋转式配气机构。

The possibility of further pollution reduction of automobile engine(four-stroke pistol type internal combustion engine) is restricted by the existing valve mechanism: 1. In gasoline engine valve system, valve-head lied inside the engine combustor to make up-and-down reciprocation, which prevented waste gas to exhaust completely. To overcome the dilution effect of residual exhaust gas, extra air-fuel mixture was added to the engine, which leads to more CO emission. 2. In diesel engine valve system, valve-head offered resistance to intake airflow, making the volumetric efficiency in an reverse ratio to the speed of the intake airflow. To maintain the volumetric efficiency, the speed of intake airflow was decreased, which will cause insufficient gas movement in the cylinder and hinder the mixing of fuel and air, thus increase CO, PM and NOx emission. Aiming all problems above, I designed a new rotation-type valve mechanism for automobile engine.