A Model Test on the Scavenging of Two-Cycle Marine Diesel Engines

Owing to investigate the scavenging process of the loop scavenging two-cycle Diesel engine, some simplified scavenge tests have been proposed and reported. In their papers the relation between the results of simplified tests and characteristics of engine performance have been directly discussed. However, the mutual relation among those results, scavenge flow and gas exchange is not clear, hence we have difficulty of interpretation about the results of simplified tests.Therefore, we made an attempt to investigate the relation among some simplified tests, scavenge flow and scavenging efficiencies. The results obtained are as follows; 1) The effect of the piston movement in the pattern of scavenging pictures does not appear. That is, if the shapes and arrangements of scavenge ports are same, same scavenging pictures are obtained in the both cases of steady flow and dynamic scavenging. 2) Comparing the two unsatisfactory scavenging pictures which depend on the scavenge port arrangement, it was found that good scavenge could not expected in case of the scavenging pictures of middle tongue rather than that of wall tongues. 3) The part of relation between the results of simplified tests and scavenging efficiencies was cleared by setting up criteria in scavenging pictures.