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Insights into the Role of Autoignition during Octane Rating
Technical Paper
2007-01-0008
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
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.
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Citation
Swarts, A. and Yates, A., "Insights into the Role of Autoignition during Octane Rating," SAE Technical Paper 2007-01-0008, 2007, https://doi.org/10.4271/2007-01-0008.Also In
References
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