Dynamometer Development Results for a Stratified-Charge DISI Combustion System

This report describes the dynamometer testing portion of the combustion system development of a direct-injection stratified-charge gasoline engine. The engine used in this study is a single-cylinder, direct-injection engine with a newly designed cylinder head comprised of 4-valves per cylinder, an intake-side-mounted DI fuel injector and a bowl-in-piston wall-guided stratified-charge combustion system. Test results detailed in this report include evaluation of four piston designs, two combustion chamber designs, and two injector spray angles. Tests were run at stratified-charge part-load, homogeneous-charge part-load, and WOT conditions. The program had aggressive goals in improving both WOT performance and part-load fuel economy while achieving Stage IV emission requirements. Tests results showed that the engine was able to meet these program goals.