INTRODUCTION

The Stanford Engine Simulation Program (ESP) is a fast-running, flexible, user-friendly interactive program, designed to run on IBM compatible personal computers or mainframes, for simulation of the thermodynamic performance of homogeneous charge engines. It was developed at Stanford University for instructional purposes, but should also be useful to engine designers. A single cylinder is considered using a zero dimensional thermodynamic analysis, a simple geometrical approach to flame structure and a one-equation dynamical turbulence model that allows the effects of turbulence on heat transfer and combustion to be examined.

The user specifies geometric parameters of the engine, including bore, stroke, rod length, valve lift and timing, and heat transfer area above the piston at TC. The program handles both conventional crankshaft engines and engines with unequal compression and expansion strokes, and a variety of valve motion programs. The user also specifies operating parameters including engine speed, spark timing, valve timing, exhaust gas recirculation, and manifold pressures if no manifold model is included. When an intake or exhaust manifold is included, the user specifies the geometry of the manifold, information on flow restrictions (throttles), and friction parameters. These and other model parameters may be saved in an engine set-up file, which is automatically loaded when the user calls ESP. The parameters can be adjusted to get reasonable agreement with actual engine data, and the model then used to study the effects of proposed design changes.