Abstract
ABSTRACT:
Knock and cyclic variability were approached in a spark ignition engine for heavy duty vehicles, fueled with LPG, with 83...87% propane and 9...15 alkenes.
While knock characteristics of propane has been already studied, it was considered hat there is a lack of information concerning a possible synergistic interaction in the nd-gas, of propane with alkenes, the second important component of LPG. Engine knock was characterized in terms of intensity and knock occurrence crank angle, based on filtered cylinder pressure data. It was found that knock characteristics of commercial LPG are very much similar to those previously found for pure propane.
Cycle-to cycle combustion variations in the engine, operated very lean and with advanced mixture homogeneity, was studied with symbolic sequence statistics and return maps. A transition to non-linear deterministic behavior was identified near the lean limit condition.