Abstract
The conventional characteristic method has been used almost exclusively in analysing the unsteady flow in internal combustion engines for a long time.
In this paper, the Two-step Lax-Wendroff's method, one of the methods called difference calculus, is proved to be very useful in the analysis of unsteady flow in internal combustion engines, because of some features of the method.
The conventional method has the disadvantages that the simulated flow quantity at a crosssection of the flow stream is not always equal to that at other sections and that the required calculation time is rather too long.
By using the Two-step Lax-Wendroff's method, the mentioned problems have been solved.
Other items discussed in this report are (1) a comparison of pulses near the ports during blow-down in an experimental unit for a single blow-down with that in a unit for periodically continuous blow-downs, (2) the wave characteristics at a pipe-end nozzle and at an orifice in the pipe, and (3) the difficulty of obtaining similar pulsations in all the connecting ducts which connect cylinders with the main exhaust pipe in actual engines.
