The paper describes the emulation of the knock measurement equipment on the CFR engine used during octane rating. It was found during engine measurements that the low-pass filtered rate-of-change of the pressure signal from Primary Reference Fuels (PRF) established the definitive metric of standard knock intensity and that non-PRF fuels exhibited similar pressure rise rates at standard knock intensity. The effect of fuel octane number, compression ratio and air-fuel ratio was also clearly distinguishable.Further modelling interpretation revealed that a non-instantaneous, cascading autoignition was a likely origin for the measured pressure development. Thermal inhomogeneities, which were the result of a heat loss gradient in the trapped mass, served to explain the observed behaviour of both RON and MON test conditions and a range of fuels of different octane numbers. A predictive model was ultimately applied to demonstrate that the pressure development and pressure rise rate can be predicted from the physical conditions in the engine, coupled to a fuel ignition delay descriptor.
Insights into the Role of Autoignition during Octane Rating
Sae Technical Papers
2007 Fuels and Emissions Conference ; 2007
2007-01-23
Conference paper
English
Insights into the Role of Autoignition during Octane Rating
British Library Conference Proceedings | 2007
|Insights into the role of autoignition during octane rating
Automotive engineering | 2007
|Investigation of the Octane Rating and Autoignition Temperature of Methanol-Gasoline Blends
SAE Technical Papers | 1980
|Investigation of the octane rating and autoignition temperature of methanol-gasoline blends
Automotive engineering | 1980
|Investigation of Kinetics of Iso-Octane Autoignition
AIAA | 2014
|