陈小强 气缸盖说明书.doc

陈小强_气缸盖说明书492QD三气门汽油机设计(气缸盖)
摘要
气缸盖是汽油机最复杂,同时也是最重要的零件之一。气缸盖与活塞、气缸构成燃烧室空间。在气缸盖内一般有进、排气道,冷却水腔、润滑油孔道,并装有配气机构和火花塞等零部件。气缸盖设计的好坏,直接影响着汽油机的动力性,经济性和可靠性。
本次设计是基于原有的492Q汽油机的基础上进行改进设计,关键问题是将两气门改成三气门,采用两个进气门一个排气门,进排气门的气门面积都有所增大,这样可以增加气体流通面积,减小流动阻力,提高充气效率,提高了动力性和经济性。汽油机采用中置凸轮轴,因此缸盖上有贯穿的推杆孔,另外还有贯穿的螺栓孔,这些在布置气道的时候都应该考虑。对于进气道而言,不仅关系到气缸的充气效率,而且还与混合气的形成及燃烧过程的气流组织等密切相关。对于排气道,应尽可能的减小流动阻力,使排气流畅的排出。同时,在设计三气门的时候,可以将火花塞中心布置,改进了燃烧过程,提高了经济性和排放性。
关键词:汽油机,气缸盖,三气门,改进
THE IMPRONEMENT OF THE DESIGN OF 492QD GASOLINE ENGINE’S CYLINDER HEAD
ABSTRACT
The cylinder head of an engine ,is the plex shape structure and one of the most ponents. The cylinder head, piston,and the pose bustion chamber together. There are intake and exhaust manifold, water jacket, the road of the oil, air introduction structure and spark etc in the cylinder head. The quality of the cylinder head’s design will affect the power performance, fuel economy and reliability directly.
This design is carried out on the base of the prior 492 gasoline engine, and the key of this design lie in changing the valves from two to three, that is two intake valves and one exhaust. Both the in and out air flow area were enlarged, which decrease the flow resistance and improve the air inflation efficiency meanwhile, thus improved its power and fuel economy. The improved cylinder head remain the same structure as the prior 2 valves engine ,which control the valves through camshaft mounted in the crankcase and tappets, so the holes of the push rod and bolt still should be arranged in the cylinder head. The arrangement of the intake manifold not only affect the intake efficiency ,but also has something to do with the form of the mixture, bustion process and anization of the air flow. As to the exhaust manifold, just decrease the flow resistance without considering the turbulence. In addition the spark could be mounted in the cylinder center vertically, so that the spark could be distributed more equality. Which can improve the quality of the mixture and