A Study of Two-Stroke Cycle Fuel Injection Engines for Exhaust Gas Purification

A fuel direct-injection system was applied to a 2-stroke engine for the purpose of reducing exhaust gas emissions, especially exhaust hydrocarbons. It was observed that fuel injection only, as an alternative to the carburetor, was not an adequate means for exhaust gas purification.

Therefore, a combined throttle and spark timing control device and a thermal reactor were also adopted. On an automotive injection engine with a swept volume of 21.7 in³, these changes succeeded in reducing hydrocarbons to 5 ppm and carbon monoxide to 0.21% in the Japanese four-mode test. The durability of the thermal reactor is not yet adequate.