Chapter 7 - Pollution from Rotary Internal Combustion Engines

Abstract

This chapter describes the operation of the rotary internal combustion engine and its pollutant emission. The rotary engine is a four-stroke engine. One of the specific features of the rotary engine is that as the rotor makes one complete rotation, the output shaft accomplishes three revolutions. Also, the rotary engine is less prone to knocking and therefore more tolerable to the fuel quality. Another feature is that its geometry is very suitable for charge stratification, as the rotor always moves the air charge past the stationary location of the spark plug and nozzles, and thus, develops the necessary flow distribution for charge stratification within the chamber. In recent years, there has been an increased interest in the development of the rotary engine fueled by hydrogen. The two main disadvantages of the rotary engines are the increased emission of unbumed hydrocarbons and higher fuel consumption. Both disadvantages are related to the long and narrow shape of the combustion chamber, resulting in high surface-to-volume (S-V) ratio (large volume of the quenching layers), increased sealing perimeter (increased gas leakage from the combustion chamber), and long flame travel (lower thermodynamic efficiency).