Development of an Image Capture and Analysis Technique for the Investigation of the Very Early Stagek of Combustion in a Lean-Burn Engine and the Detection of a Novel Early Combustion Phase Which Correlates with Subsequent Cycle Quality

Abstract

An imaging technique has been developed which allows investigation of the development of the very earliest combustion events in a IC (internal combustion) engine. It utilizes the high-speed electronic photography capabilities of an Imacon camera enhanced by an image intensifier. The framing sequence obtained is captured via a CCD camera and framestore. Using optimally designed image filtering techniques it is possible to separate out individual dynamic regimes in these early combustion images. The ability of this technique to extract characteristic features of the image evolution at the very earliest phase of combustion immediately revealed the presence of a previously unreported feature. This novel aspect is the presence of clearly separate combustion regimes which are typically only resolvable in the very early phase after ignition, prior to detectable pressure rise due to heat release. The characteristics of the regimes observed in this early phase are found to correlate well with the subsequent gross combustion behaviour of the cycle.