Adaptation of a Compact High Speed SI Engine for Supercharging in base of Numerical-Simulation

The application of supercharging as a measure to improve the engine performances is a basic feature for downsizing concepts applied for advanced automobile engines.

The adaptation of such concept to a high speed compact SI engine with a speed range between 2.000rpm and 9.000rpm forms the object of this paper.

The determination of the special adapted control strategy as well as the necessary modifications of the basic engine were conducted in this work by mean of simulation with the 1D Code BOOST and coupled modules from 3D simulation by the code FIRE. The used models were generated and calibrated going out from the individual components to be connected: an 1000cc/2 cylinder/4 stroke engine and a screw type compressor.

The adaptation of the engine to the supercharging concept, imposed modifications of the valve course and timing as well as of the intake ducts shaping. Furthermore the influence of compression ratio and the cooling strategy and several part load supercharging strategies were analyzed.