旋转活塞式气动发动机气口设计

Design of air ports for rotary piston air-powered engine

针对旋转活塞式气动发动机工作原理及差速驱动机构结构上的特点,分析发动机配气的需求及特点,选定位置配气方式,确定进排气口的布置形式.对进排气口的大小、开始位置与差速驱动机构各个构件的尺寸及压缩比之间的关系,以及机构各个构件尺寸对于极限压缩比的影响进行分析.在保证选定压缩比小于极限压缩比的前提下,优选一组机构构件尺寸,计算进排气口大小和开始位置相对于构件各个尺寸的变化率.研究结果表明:排气口的大小不受构件尺寸及压缩比的影响,进气口参数随着构件尺寸及压缩比的变化而变化;曲柄长度对于气口参数的影响最大,可以通过改变曲柄长度有效地调节气口参数.

The requirement and characteristics of gas distribution of rotary piston air-powered engine were studied based on the analysis of working cycle and driving mechanism,and the arrangement of the gas ports was determined after choosing the piston shutting air ports as the primary control method of air distribution system.The relationships of size and initial positions of air ports,lengths of parts of differential driving mechanism and compress ratio were studied,based on which the influence of parts lengths on the limited compression ratio was analyzed.Ensuring the compression ratio smaller than the limited ratio,the changing ratio of air ports parameters to parts lengths was studied after setting parts lengths as the optimal parameters.The results show that the size of the exhausting port is independent on the parts lengths and the compression ratio,while the parameters of intaking ports vary with the parts lengths and the compression ratio.The length of crank has the biggest effect on the parameters of air ports which can be effectively modified by changing the crank length.