Abstract
One of the major sources of unburned hydrocarbons (HC) from internal combustion engines is the existence of a space surrounded in the piston top land, top ring, and cylinder wall. This space is called a piston ring crevice. In this paper, the mathematical model on the flow in the piston ring crevice is described. It makes a piston ring crevice a one-dimensional model and it computes. It considers an unsteady flow and it considers the compressibility of gas in the crevice. By grasping the flow of detailed gas in the piston ring crevice when considering an unsteady flow, it clarifies by what phenomenon an exit velocity from the crevice is dominated.
