Non-intrusive Temperature Measurements during the Compression Phase of a DI Diesel Engine
Non-intrusive temperature measurements based on single-line laser-induced fluorescence of molecular oxygen in the transparent IDEA Diesel engine were investigated. Oxygen molecules were excited to fluorescence with a narrowband, tunable ArF excimer laser at 193 nm. The resulting fluorescence signals were recorded with an image-intensified CCD camera. The temperature increase during the compression phase of the four-cylinder direct injection Diesel engine could be evaluated from the LIF signals. In the crank angle range of the measurements, good agreement between measured and calculated temperatures (polytropic compression) was observed.