Thermal Deformation of the Clearance between Cylinder and Piston : The Case of an Air-cooled Two-stroke-cycle Engine

Abstract

The clearance between cylinder and piston of the internal combustion engine is expected to be deformed by heating in operation, and its thermal deformation is closely related to lubrication, cooling, friction and blow-by. To measure the thermal deformation of this clearance, an air-cooled two-stroke-cycle engine was chosen as an experimental engine. The applied measuring method, called " Quick Stopping Method " by the authors, is practical because the thermal deformation can be easily measured by dial gauges. As a result of this series of experiments, it was revealed that local close-fit condition sometimes arose between cylinder and piston even in its normal operation.