Mapping K factor variations and its causes in a modern, spark-ignition engine

Abstract

The Research Octane Number (RON) and the Motor Octane Number (MON) are primary fuel properties that characterize gasoline's knock resistance in spark ignition engines. The utility of these two metrics, however, has been questioned with advancements in engine technologies that significantly change the thermochemical environment inside the cylinder. The Octane Index, OI = (1-K)·RON + K·MON, has therefore been proposed to characterize the knock resistance in modern engines where K weights the relative contribution of the RON and MON and is primarily determined by engine design and operating conditions. Quantifying the K factor is central to understanding a fuel's anti-knock performance in a mod..