利用排气动力提高二冲程汽油机的性能研究

IMPROVING THE PERFORMANCES OF TWO-STROKE ENGINES BY THE USE OF EXHAUST PRESSURE

在二冲程汽油机的排气过程中 ,采用排动管向排气口反射负压和正压波 ,负压波的峰值在下死点附近到达排气口 ,有利于气缸内的废气排出 ,正压波的峰值在扫气口关闭时到达排气口 ,将逃逸到排气管中的混合气再压回气缸 ,改善换气过程 ,提高充气效率。其结构参数为 LS455mm,LK 2 40 mm,LP3 8mm,LW1 3 0mm,LV1 50 mm,θ=1 0°,φ=2 0°的排气管 (带消声器 )。在 CT 50汽油机上与原消声器对比 ,功率可提高 1 7% ,比油耗下降 9.2 %。

Both expansion and compression waves are reflected to the exhaust hole in the course of exhausting in two stroke engines. The former waves are beneficial for the exhausting of the burnt gases in the cylinder while the latter waves press the mixed gases, which have escaped into the exhaust pipe, back into the cylinder and thus increase the filling efficiency. The structure parameters of the muffler modified are L S 455 mm, L K 24 mm, L P 38 mm, L W 30 mm, L V 150 mm,θ=10° and φ=20°. Compared with the common muffler in the CJ 50 model engine, the new modified muffler increases output power by 17% and decreases fuel consumption by 9.2%.