High Bandwidth Heat Transfer Measurements in an Internal Combustion Engine Under Low Load and Motored Conditions

摘要

Heat transfer between the working fluid and the combustion chamber in an internal combustion engine is one of the most important parameters for cycle simulation and analysis. The heat transfer influences the in-cylinder pressure and temperature levels, engine efficiency, and exhaust emissions. Most of the current research carried out on combustion chambers focuses on gas temperature measurement by Coherent Anti-Stokes Raman Scattering (CARS) and heat transfer measurement by thermocouples. Heat transfer measurement by thermocouples leads to poor bandwidths and large uncertainties. A more advanced experimental technique for heat transfer measurement used in gas-turbine engine research, platinum thin film resistance thermometers, was recently employed in a single cylinder engine. Heat transfer rate measurements were successfully obtained on the piston surface and cylinder head exposed to the combustion gases. The thin film gauge system has a frequency response of around 100kHz and therefore can track the heat transfer rate changes on the piston surface and cylinder head adequately. Measurements taken with the engine motored and at low load are presented and discussed. (13 figures, 12 refs.).