Effect of Exhaust Pipe System upon the Performance Characteristics of a Two-Cycle Diesel Engine : (1st Report, The Influence of Exhaust Pipe Length)

Abstract

This paper deals with the influence of the exhaust pipe length upon the performance characteristics of a two-cycle Diesel engine. The two-cycle uniflow scavenged three-cylinder Diesel engine was employed, and the length of each exhaust pipe was changed from 20 cm to 420 cm. The following results were obtained. (1) The optimum performance was obtained at the following pulsation coefficients q, i. e. q=0.24, 0.70 and 1.16, q being defined as q=nL/15c, where n : crankshaft revolutions per minute, L : length of the exhaust pipe and c : sonic velocity in the exhaust pipe. (2) Theoretical treatment performed by one of the present authors showed fair coincidence with the experimental results. (3) The difference of output developed by the engine at good tuning and that at poor tuning was about 15%. (4) In the practical application of the present results especially to the variable speed engines, a shorter optimum exhaust pipe length is preferable to the longer one.