Three-stage autoignition of gasoline in an HCCI engine: An experimental and chemical kinetic modeling investigation

Journal Article · Mon Dec 15 04:00:00 EST 2008 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2008.04.022· OSTI ID:21125482

Machrafi, Hatim; Cavadias, Simeon ^[1]

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1. UPMC Universite Paris 06, LGPPTS, Ecole Nationale Superieure de Chimie de Paris (France)

The alternative HCCI combustion mode presents a possible means for decreasing the pollution with respect to conventional gasoline or diesel engines, while maintaining the efficiency of a diesel engine or even increasing it. This paper investigates the possibility of using gasoline in an HCCI engine and analyzes the autoignition of gasoline in such an engine. The compression ratio that has been used is 13.5, keeping the inlet temperature at 70 C, varying the equivalence ratio from 0.3 to 0.54, and the EGR (represented by N{sub 2}) ratio from 0 to 37 vol%. For comparison, a PRF95 and a surrogate containing 11 vol% n-heptane, 59 vol% iso-octane, and 30 vol% toluene are used. A previously validated kinetic surrogate mechanism is used to analyze the experiments and to yield possible explanations to kinetic phenomena. From this work, it seems quite possible to use the high octane-rated gasoline for autoignition purposes, even under lean inlet conditions. Furthermore, it appeared that gasoline and its surrogate, unlike PRF95, show a three-stage autoignition. Since the PRF95 does not contain toluene, it is suggested by the kinetic mechanism that the benzyl radical, issued from toluene, causes this so-defined ''obstructed preignition'' and delaying thereby the final ignition for gasoline and its surrogate. The results of the kinetic mechanism supporting this explanation are shown in this paper. (author)

• OSTI ID: 21125482
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 4 Vol. 155; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
AUTOIGNITION
BENZYL RADICALS
COMBUSTION
COMBUSTION KINETICS
COMPARATIVE EVALUATIONS
DIESEL ENGINES
EFFICIENCY
GASOLINE
HEPTANE
OCTANE
Obstructed preignition
SIMULATION
TEMPERATURE RANGE 0273-0400 K
TOLUENE
Three-stage autoignition