Abstract
In the previous paper, exhaust-pulsation of UD-3 engine having simple straight pipe exhaust system was experimented. The apparatus was identical with that descrived in the 1st report. In the present paper the influences of the exhaust pipe system having diffusers, nozzles, bends or elbows on the performance characteristic is reported. Results are as follows. a) For the case of exhaust pipe with diffusers, the pulsation coefficient for a straight pipe is available with the equivalent length derived from the impedance theory. Only a few percent increase in power was observed in comparison with straight pipe system in a favorable condition. b) For the nozzle, the pulsation effect can not be expected below an area ratio of 0.3, particularily in the case of a super-charged engine. From the view of an effective exhaust energy, a shorter pipe length is preferabl. c) The bend effect has little influence on the performance, judging from the pressure wave observations and the propagation velocity (dx/dt=u±c).
