Conference Proceedings

The effect of nitric oxide on knock onset of iso-octane in a CFR spark-ignition engine

Z Chen, H Yuan, Y Yang, M Brear

ASPACC 2015 - 10th Asia-Pacific Conference on Combustion | Combustion Institute | Published : 2015

Abstract

This paper investigates the impact of nitric oxide (NO) on the knock-onset timing in a standard CFR octane rating engine fuelled with iso-octane. NO was introduced at the engine intake where O2 is maintained at 21%. The experiments employed a fuel rich operating condition (λ=0.7), in order to alleviate the impact of the residual NO on knock previously reported [1]. Intake air temperatures (IAT) were varied from 52°C to 200°C to study the dependence of NO impact on temperature. Results show that the impact of NO on knock-onset timing varied significantly with IAT. At IAT=52oC, NO advanced knock-onset timing at low addition levels (≤ 200 ppm) but retarded it at higher levels. As IAT increased,..

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