Masashi Marubara

Mixture formation of direct gasoline injection engine:: in-cylinder gas sampling using fast flame ionization detector

Abstract Local mixture concentration near the spark plug of a direct gasoline injection engine was observed by a fast flame ionization detector. To ensure combustion stability in DISC (Direct Injection Stratified Charge) operation using conventional lean burn intake ports, the swirl ratio and the piston configuration were optimized. Swirl is needed to retain well-vaporized and stable mixture near the spark plug, especially under light load. Also, adequate volume in the piston cavity is required for trapping curved fuel spray. Measurement with a fast flame ionization detector was very effective for understanding the mixture features on DISC operation.