Measurement of Piston Temperature of Spark-Ignition Engine

Abstract

This report deals with temperature measurement of the piston surface. The test engine used is a four-stroke spark-ignition engine with a water cooled single cylinder, bore×stroke being 114.3×140 mm and its output is 6 HP at 850 r.p.m. The iron-constantan thermocouple is used and its hot junction is located in the surface center of the aluminium-alloy piston head. In order to measure accurately the periodic temperature change, the hot junction is constructed with the metallic film. Two wires-iron and constantan-are electrically insulated and let to the piston surface, and there they are shorted by the metallic film. The film is constructed successfully with the aluminium metallikon. For connecting the thermocouple to the amplifier, the input transformer is used. By these methods, the temperature change of the aluminium-alloy piston has been measured without being disturbed by the spark plug.