GM’s HCCI – In-Vehicle Experience with a Future Combustion System

Authors

Dipl.-Ing. S. Pritze, Dipl.-Ing. A. Königstein, Adam Opel GmbH, Rüsselsheim; A. Rayl, M.S.E.E., C.-F. Chang, Ph.D. M.E., P. M. Najt, M.S.M.E., Prof.Dr.-Ing. U. D. Grebe, General Motors LLC, Warren / Pontiac, USA

Year

2010

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 716

Summary

Homogeneous Charge Compression Ignition (HCCI) stands at General Motors (GM) for the auto-ignition of a homogeneous air-fuel mixture in a gasoline engine. HCCI enables unthrottle operation under part load conditions with the high potential for fuel consumption reduction at lowest NOx emission levels even with lean mixtures. It is capable to use worldwide available fuel qualities with conventional exhaust aftertreatment. Important requirements for the application in a vehicle are the realization of a large usable steady state map covering lowest engine loads including idle operation and an outstanding transient combustion performance in terms of robustness and responsiveness. The prerequisites to achieve this were set based on a spray-guided gasoline direct injection with a strategy to control the residuals by trapping and recompressing them in the combustion chamber and sensing of individual cylinder pressure. The main characteristics of the combustion system will be discussed. The application in a vehicle sets new targets in terms of engine controller requirements and the complexity of the control algorithms. Considering only indirect control of combustion being very sensitive against extraneous impacts, it becomes extremely challenging to realize robust transitions among the various operation modes. The results achieved with the integration of the presented HCCI combustion system in prototype vehicles of the midsize segment support the chosen development path. Further improvements can be expected considering the latest achievements of the combustion system development.