The new AVL CSI Engine - HCCI Operation on a Multi Cylinder Gasoline Engine

The practical application of homogeneous autoignition combustion on a 4-cylinder gasoline production engine is mainly determined by system integration and control strategies under real world boundaries.

Self ignition conditions are reached by re-breathing of hot exhaust gas into the combustion chamber during the intake stroke. The CSI engine (Compression and Spark Ignition engine) shows maximum flexibility for a precise internal residual gas control with only moderate modification of engine hardware. New algorithms are necessary in order to achieve acceptable NVH behavior (Noise Vibration Harshness), especially for the mode transition between spark ignition (SI) and homogeneous charge compression ignition (HCCI) operation.

The paper describes the steady state and transient behavior of the CSI 4-cylinder engine and the benefits in fuel consumption and exhaust gas emission compared to the base conventional spark ignited gasoline engine and gives a detailed view on the required combustion control strategies, with focus on mode transitions.