An Experimental study was performed on a 2-stroke gasoline caburetor engine from which, as known, 2-stroke SI engine has lower thermal efficiency and higher HC emission than that of 4-stroke one due to short-circuiting. In the process of engine test, it was discovered that, different from 4-stroke engine, cylinder pressure before spark were varied because of the changing in-cylinder charge temperature as a result of different degree of scavenging and short-circuiting at each cycle. A limited number of tests for the application of an air-assisted fuel injecter was tried to operate the engine as the direct injection stratified charge mode.
The original intention to reduce HC emission by eliminating the short-circuiting was not achieved due to insufficient time available and left as the task for the future.
