Title: Performance and exhaust emissions of a two-stroke spark-ignition engine with a direct-injection system

Authors: Yasuhiro Daisho, Takeshi Saito, Noriaki Ishibe, Mitsuhiro Tsukada, Masashi Yukawa

Addresses: Department of Mechanical Engineering, Waseda University 3-4-1 Okubo, Shinjuku-ku, Tokyo, 169 Japan. ' Department of Mechanical Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo, 169 Japan. ' Department of Mechanical Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo, 169 Japan. ' Yamaha Motor Co. Ltd, Japan. ' Fuji Heavy Industries Ltd, Japan

Abstract: A direct fuel-injection system has been adapted to a small two-stroke spark-ignition engine to prevent the charge from flowing through the cylinder during the scavenging process. The injection system consists of a jerk-type pump and a single-hole nozzle which supplies gasoline to the cylinder. Engine tests were carried out for comparison with the carburettor version of the same engine. The results show that the direct-injection version can achieve greatly improved thermal efficiency and lower HC and CO emissions without intake throttling. In addition, NOx can be reduced to a much lower level than that of the ordinary four-stroke engine. Heat release analysis and high-speed photography indicate that stratified charge combustion takes place in the direct-injection engine.

Keywords: direct fuel injection; exhaust emissions; lean combustion; spark-ignition engines; two-stroke engines; hydrocarbon emissions; carbon emissions; exhaust emissions; environmental pollution.

DOI: 10.1504/IJEP.1991.028481

International Journal of Environment and Pollution, 1991 Vol.1 No.1/2, pp.113 - 124

Available online: 18 Sep 2009 *

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