Pressure Sensitivity of HCCI Auto-Ignition Temperature for Primary Reference Fuels

The current research focuses on creating a homogeneous charge compression ignition (HCCI) fuel index suitable for comparing different fuels for HCCI operation. One way to characterize a fuel is to use the auto-ignition temperature (AIT). The AIT can be extracted from the pressure trace. Another potentially interesting parameter is the amount of low temperature heat release (LTHR) that is closely connected to the ignition properties of the fuel. The purpose of this study was to map the AIT and the amount of LTHR of different oxygenated reference fuels in HCCI combustion at different cylinder pressures. Blends of n-heptane, iso-octane, and ethanol were tested in a cooperative fuels research (CFR) engine with a variable compression ratio. Five different inlet air temperatures ranging from 50 °C to 150 °C were used to achieve different cylinder pressures and the compression ratio was changed accordingly to keep a constant combustion phasing, CA50, of 3 ± 1 deg after top dead center (TDC). The experiments were carried out in lean operation with a constant equivalence ratio of 0.33 and with a constant engine speed of 600 rpm. The amount of ethanol needed to suppress the LTHR from different primary reference fuels (PRFs) was evaluated. The AIT and the amount of LTHR for different combinations of n-heptane, iso-octane, and ethanol were charted.

Download Full-text

Engine Speed Effect on Auto-Ignition Temperature and Low Temperature Reactions in HCCI Combustion for Primary Reference Fuels

10.4271/2014-01-2666 ◽

2014 ◽

Cited By ~ 8

Author(s):

Ida Truedsson ◽

William Cannella ◽

Bengt Johansson ◽

Martin Tuner

Keyword(s):

Low Temperature ◽

Ignition Temperature ◽

Engine Speed ◽

Hcci Combustion ◽

Auto Ignition ◽

Primary Reference ◽

Speed Effect ◽

Primary Reference Fuels

Download Full-text

Pressure Sensitivity of HCCI Auto-Ignition Temperature for Oxygenated Reference Fuels

ASME 2012 Internal Combustion Engine Division Fall Technical Conference ◽

10.1115/icef2012-92074 ◽

2012 ◽

Cited By ~ 2

Author(s):

Ida Truedsson ◽

Martin Tuner ◽

Bengt Johansson ◽

William Cannella

Keyword(s):

Compression Ratio ◽

Ignition Temperature ◽

Equivalence Ratio ◽

Engine Speed ◽

Pressure Sensitivity ◽

Hcci Combustion ◽

Air Temperatures ◽

Auto Ignition ◽

Temperature Heat ◽

Pressure Trace

The current research focuses on creating an HCCI fuel index suitable for comparing different fuels for HCCI operation. One way to characterize a fuel is to use the Auto-Ignition Temperature (AIT). The AIT can be extracted from the pressure trace. Another potentially interesting parameter is the amount of Low Temperature Heat Release (LTHR) that is closely connected to the ignition properties of the fuel. The purpose of this study was to map the AIT and amount of LTHR of different oxygenated reference fuels in HCCI combustion at different cylinder pressures. Blends of n-heptane, iso-octane and ethanol were tested in a CFR engine with variable compression ratio. Five different inlet air temperatures ranging from 50°C to 150°C were used to achieve different cylinder pressures and the compression ratio was changed accordingly to keep a constant combustion phasing, CA50, of 3±1° after TDC. The experiments were carried out in lean operation with a constant equivalence ratio of 0.33 and with a constant engine speed of 600 rpm. The amount of ethanol needed to suppress LTHR from different PRFs was evaluated. The AIT and the amount of LTHR for different combinations of n-heptane, iso-octane and ethanol were charted.

Download Full-text

An experimental and numerical analysis of the HCCI auto-ignition process of primary reference fuels, toluene reference fuels and diesel fuel in an engine, varying the engine parameters

Fuel Processing Technology ◽

10.1016/j.fuproc.2008.03.007 ◽

2008 ◽

Vol 89 (11) ◽

pp. 1007-1016 ◽

Cited By ~ 41

Author(s):

Hatim Machrafi ◽

Simeon Cavadias ◽

Philippe Gilbert

Keyword(s):

Numerical Analysis ◽

Diesel Fuel ◽

Ignition Process ◽

Auto Ignition ◽

Primary Reference ◽

Primary Reference Fuels

Download Full-text

An experimental and numerical analysis of the influence of the inlet temperature, equivalence ratio and compression ratio on the HCCI auto-ignition process of Primary Reference Fuels in an engine

Fuel Processing Technology ◽

10.1016/j.fuproc.2008.05.019 ◽

2008 ◽

Vol 89 (11) ◽

pp. 1218-1226 ◽

Cited By ~ 33

Author(s):

Hatim Machrafi ◽

Simeon Cavadiasa

Keyword(s):

Numerical Analysis ◽

Compression Ratio ◽

Equivalence Ratio ◽

Inlet Temperature ◽

Ignition Process ◽

Auto Ignition ◽

Primary Reference ◽

Primary Reference Fuels

Download Full-text

A parametric study on the emissions from an HCCI alternative combustion engine resulting from the auto-ignition of primary reference fuels

Applied Energy ◽

10.1016/j.apenergy.2008.02.005 ◽

2008 ◽

Vol 85 (8) ◽

pp. 755-764 ◽

Cited By ~ 46

Author(s):

Hatim Machrafi ◽

Simeon Cavadias ◽

Jacques Amouroux

Keyword(s):

Parametric Study ◽

Combustion Engine ◽

Auto Ignition ◽

Primary Reference ◽

Primary Reference Fuels

Download Full-text

Influences of isomeric butanol addition on anti-knock tendency of primary reference fuel and toluene primary reference fuel gasoline surrogates

International Journal of Engine Research ◽

10.1177/1468087419850704 ◽

2019 ◽

Vol 22 (1) ◽

pp. 39-49 ◽

Cited By ~ 10

Author(s):

Yunchu Fan ◽

Yaozong Duan ◽

Dong Han ◽

Xinqi Qiao ◽

Zhen Huang

Keyword(s):

Combustion Kinetics ◽

Molar Percentage ◽

Research Octane Number ◽

Fuel Blends ◽

Ignition Delay Times ◽

Auto Ignition ◽

Delay Times ◽

Primary Reference ◽

Primary Reference Fuels

The anti-knock tendency of blends of butanol isomers and two gasoline surrogates (primary reference fuels and toluene primary reference fuels) was studied on a single-cylinder cooperative fuel research engine. The effects of butanol molecular structure (n-butanol, i-butanol, s-butanol and t-butanol) and butanol addition percentage on fuel research octane numbers were investigated. The experimental results revealed that butanol addition to either PRF80 or TPRF80 increased research octane numbers, and the research octane numbers of fuel blends showed higher linearity with the molar percentage than with the volumetric percentage of butanol addition. Furthermore, the research octane number boosting effects of butanol isomers were observed to change with the fuel compositions, that is, i-butanol >s-butanol >n-butanol >t-butanol for primary reference fuels and i-butanol >s-butanol >t-butanol >n-butanol for toluene primary reference fuels. In addition, butanol/primary reference fuel blends exhibited higher research octane numbers than butanol/toluene primary reference fuel blends. We thereafter tried to elucidate the underlying fuel combustion kinetics for the observed anti-knock quality of different butanol/gasoline surrogate blends. It was found that the measured research octane numbers of fuel blends showed the best correlation with the calculated ignition delay times at the thermodynamic condition of 770 K and 2 MPa, and the reaction sensitivity analysis in auto-ignition at this condition revealed that the H-abstraction reactions of butanol isomers by OH radical suppressed fuel reactivity, thus elevating the fuel research octane numbers when butanol was added to the gasoline surrogates. Compared with the butanol/primary reference fuel blends, the positive sensitive reactions related to n-heptane were of higher importance, while the inhibitive effects of sensitive reactions related to butanol and iso-octane decreased for the toluene primary reference fuel/butanol blends, thus leading to lower research octane numbers of the toluene primary reference fuel/butanol blends than those of the butanol/primary reference fuel blends.

Download Full-text