'Designer diagnostics' for developing direct-injection gasoline engines

The primary motivation for stratified-charge spark-ignited direct injection (SC-SIDI) engines is to maximize fuel economy by operating the engine with minimal (preferably no) throttling at part load. This requires control of the fuel-air mixing process to create a fuel cloud around the spark plug that is favorable for ignition and complete combustion in every engine cycle. This paper illustrates experimental techniques that have been developed to measure key aspects of the incylinder fuel-injection, ignition, combustion and emissions-formation processes. Most of these techniques rely on high-speed digital imaging and in-situ calibration in order to characterize dynamic in-cylinder phenomena that vary substantially from cycle to cycle