Economy and NO emission potential of an SI variable R/L engine

A theoretical analysis of the spark ignition VR/LE engine with the variable crank-radius to connecting-rod-length ratio R/L has been performed with the help of the thermodynamic-type model (zero-dimensional) including NO formation submodel. The analysis has made it possible to determine the changes of some basic output engine parameters: thermal efficiency, work and NO concentration, as a result of the engine thermodynamic cycle variations. A comparison between the VR/LE and conventional engines is presented. The ranges of the phase angle which can give the gain in efficiency and NO emission reduction are also determined. The analysis has confirmed that the VR/LE engine concept has remarkable economy potential with application to the SI engines and it is worth performing a research with an actual engine.