The Unsteady Gas Exchange Characteristics of a Two-Cycle Engine

760644

02/01/1976

Event
1976 SAE International Off-Highway and Powerplant Congress and Exposition
Authors Abstract
Content
The theoretical modelling of the scavenge process for a naturally aspirated two-cycle engine is described and employed in conjunction with an unsteady gas dynamic analysis of flow in the engine ducting. Programmed for a digital computer, the results of this theoretical study are shown in relation to a 250 cm3 engine with values of predicted charging efficiency, scavenging efficiency, and delivery ratio given as a function of engine speed. These are compared with measured values of scavenging efficiency and the usual performance characteristics of power, mean effective pressure, delivery ratio, and specific fuel consumption. Also compared are the measured and predicted pressure diagrams taken in the cylinder, the crankcase, and the exhaust and inlet ducts. The design of a somewhat unique cylinder gas sampling valve of the mechanical type is described and its usage discussed both theoretically and practically.
Meta TagsDetails
DOI
https://doi.org/10.4271/760644
Pages
23
Citation
Blair, G., and Ashe, M., "The Unsteady Gas Exchange Characteristics of a Two-Cycle Engine," SAE Technical Paper 760644, 1976, https://doi.org/10.4271/760644.
Additional Details
Publisher
Published
Feb 1, 1976
Product Code
760644
Content Type
Technical Paper
Language
English