Laser-Induced Phosphorescence Measurements of Combustion Chamber Surface Temperature on a Single-Cylinder Diesel Engine

Non-intrusive, crank-angle resolved measurements of piston temperature have been performed in a single-cylinder direct-injection (DI) Diesel engine operating under highly-dilute low-temperature combustion (LTC) conditions. The laser-induced phosphorescence (LIP) technique exploits the temperature-dependent characteristics of rare-earth or transition metal doped ceramic phosphors. This paper describes the calibration procedure and subsequent application of the technique to measure piston surface temperature in a single-cylinder, optically-accessible Diesel engine for various parametric variations including fueling rate and injector nozzle characteristics. In addition, measurements of the nozzle tip temperature of a Diesel injector are also reported. Furthermore, a fiber-optic solution has been developed which enables piston surface temperature measurements to be performed in standard metal (i.e. non-optical) single-cylinder and multi-cylinder engines. Quantification of combustion chamber surface temperature using the LIP technique with crank angle resolution provides experimental data which will be useful not only for the validation of a range of numerical models but also in the development of new combustion concepts. For example, the LIP technique could be a useful tool to (1) quantify the role of combustion chamber surface temperature on pre-ignition / rumble phenomena in highly-downsized, direct-injection gasoline engines and (2) determine and optimise thermal management strategies in single cylinder and multi-cylinder engines.