Design and Simulation of Engines: A Century of Progress

The paper discusses briefly the development of the theory of unsteady gas flow from a position of being totally misunderstood from the turn of this century until the 1940's, developed in the 1950's, and from which juncture the advent of the digital computer has turned such theory into a comprehensive design tool by the present day.

While the most extensive use of this design method is for engines with a high performance specification, its employment as a design tool for industrial engines has been largely ignored. In the paper, a design for a small generating set engine at 3600 rpm is examined in great detail and the use of pressure wave effects is shown to enhance the engine performance considerably, either in terms of power gain, reduction of fuel consumption, reduction of hydrocarbon emissions, or reduction of noise levels. Two design variations with a common swept volume of 150 cm³ are examined in this manner; one is a four-stroke cycle engine and the other is a two-stroke cycle unit. Hence, further useful direct comparisons of power output, fuel consumption rates, and noise and exhaust emissions levels become possible between these two demonstrator engines operating on different cycles.