Modelling and Experimental Study of Thermal Management System for HCCI

This work presents a mass and enthalpy balance model for the air intake system of a multi-cylinder Homogenous Charge Compression Ignition (HCCI) gasoline engine. To achieve controlled auto-ignition across a wide range of engine conditions, a system for management of flow and temperature is installed at the air intake to enable the necessary regulation of temperatures and pressures at the inlet ports. In order to facilitate this control, a complete simulation model of the thermal system for a pressure-boosted multi-cylinder HCCI engine has been developed. The system includes a heat exchanger to heat the charge air, a supercharger to boost the charge air pressure, supercharger bypass and finally an intercooler, so that a wide range of combinations of pressures and temperatures can be achieved at the intake ports.

The paper discusses the issues associated with control of the properties of charge air needed to extend the envelope of HCCI operation. This extension is one of the main objectives of the CHASE (Controlled Homogeneous Autoignition Supercharged Engine) project. General principles of the model are outlined and some non-standard submodels for the individual components are presented in detail. Model calibration and validation are presented compared with measured data, experimental results for extensions of HCCI regime possible with the use of thermal management as predicted by the model is demonstrated and lastly the guidelines for control of the system are elaborated.