Model of flow through a poppet valve of piston engine and an approach to parameter identification

Abstract

A semi-empirical model of flow through a poppet valve of a piston engine is presented. The model is based on a hypothetical stationary separated flow in the valve gap. The model is closed by regression equations for the quantities characterizing the jet contraction and the losses of the total pressure prior to the contraction. To evenly refine the model (for different flow conditions and for different valve lifts), it is proposed to automatically adjust the parameters of the built-in regression equations on the basis of the detailed flow simulations in 2-D. The approach to calibration the model using data obtained by blowdowns or 3-D simulations is also shown. Applicability of the model to unsteady problems solved in 1-D is discussed.