Delphi Reports Advances in Gasoline Compression-Ignition

Researchers say their work on gasoline compression-ignition in a single-cylinder test engine suggests the technology could boost a midsize car's average fuel economy more than 50%.

The group, working under a $7.5 million grant from the U.S. Dept. of Energy, includes Delphi Corp., Hyundai America Technical Center, Wisconsin Engine Research Consultants and the University of Wisconsin-Madison.

Researchers from Delphi reported the group's achievements during this week's SAE High Efficiency IC Symposium and World Congress events in Detroit. Their technical paper #2012-01-0384 is available HERE.

Gasoline compression-ignition essentially a diesel engine running on gasoline requires a formidable array of variable controls to deliver good performance over the range of speeds and loads encountered by a typical car.

The group says it achieved low-temperature combustion by employing multiple late injection, intake boost and moderate exhaust gas recirculation. Researchers used EGR in light-load conditions to promote auto-ignition, a triple injection scheme at moderate loads to maintain high thermal efficiency and late intake valve closing at high loads to reduce the compression ratio.

The group says they were able to achieve exceptionally low NOx and particulate emissions of less than 0.2 g/kWh using RON 91-octane gasoline at low-to-moderate injection pressures. They also report very low exhaust gas particulates.

The team says its results verify the potential for a practical gasoline compression-ignition engine. Future research will focus on multi-cylinder engines and explore performance during cold starts and transient load conditions.