HCCI - from Lab to the Road

Authors

Dr.-Ing. M. Alt, Prof. Dr.-Ing. U. D. Grebe, J. R. Dulzo, M.S.E.E., V. A. Ramappan, M.S.M.E., General Motors Powertrain, Pontiac; Dipl.-Ing. P. Kafarnik, General Motors Powertrain Europe, Rüsselsheim; P. M. Najt, M.S.M.E., General Motors Research & Development, Warren

Year

2008

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 672

Summary

Homogeneous Charge Compression Ignition (HCCI) - Engine experts have dreamed about it, talked about it, and lectured about it for decades. Some even call it the “most awaited advanced combustion technology” of the past 30 years. GM demonstrated this combustion process in two drivable concept vehicles, a 2007 Saturn Aura and a 2007 Opel Vectra.

Transferring HCCI technology from single-cylinder steady-state engine operation in the laboratory to a modern passenger car had been a significant challenge. However, fasttransient HCCI operation has been demonstrated in prototype vehicles using a combination of variable valvetrain, central direct injection, cylinder-pressure sensing and cycle-to-cycle engine controls. The variable valve train is required to control the in-cylinder temperature with residual-gas. The direct injection of fuel is mandatory for this concept and allows the balancing of the cylinders and cycle-by-cycle multiple fuel injection quantity and timing control. Cylinder-pressure sensing with robust, closed-loop engine controls is necessary to compensate for the influences of fuels and ambient conditions. In combination, these enabling technologies are shown to provide HCCI operation over a large speed-load range. To enable the HCCI operation, engine hardware is chosen to keep today’s benefits of a gasoline engine in cost, power and weight while improving fuel efficiency up to 15% versus a port fuel injected engine. GM will work on the remaining challenges to transfer the high thermodynamic potential of HCCI engines into everyday driving conditions.

Order Members Login