Characterization of Glow Plug and HCCI Combustion Processes in a Small Volume at High Engine Speed - Load Range, Emission Characteristics and Optical Diagnostics

University dissertation from Lund University

Abstract: The objective of this research that has taken me halfway to my PhD degree was to understand how HCCI combustion behaves in a small volume at high rotational speed. The investigation has been carried out using a modified model airplane engine. The whole study can be divided into two main parts; in the first, the nature of the glow plug combustion was investigated through experiments on a metal engine and by use of optical diagnostics. Once the glow plug combustion process was fully understood, the engine was modified in order to achieve pure HCCI operations. Initially, a basic investigation was carried out using a metal and optical engine. Later, further research was performed on the main parameters affecting HCCI operations in such a small volume, i.e. the quenching distance, wall temperature and combustion chamber geometry. In addition to these studies, a model for calculating the amount of retained gas in a 2-stroke engine was developed and a miniature HCCI free piston engine was designed from scratch.