Numerical study of combustion characteristics of a natural gas HCCI engine with closed loop exhaust-gas fuel reforming

In this study, a mechanism containing ethanol reactions is employed and the effects of exhaust gas fuel reforming on operation parameters such as ignition timing, burn duration, temperature, pressure and NOx emission are studied in which a homogeneous mixture is assumed. The results show that hydrogen in the form of reformed gas helps in lowering the intake temperature required for stable HCCI operation. It is concluded that the addition of hydrogen advances the start of combustion in the cylinder. This is a result of the lowering of the minimum intake temperature required for auto-ignition to occur during the compression stroke, resulting in advanced combustion for the same intake temperatures. The obtained results from the model are compared with the experimental data published in the literature and the comparison showed a reasonable compatibility.

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Multidimensional modeling of the effect of Exhaust Gas Recirculation (EGR) on exergy terms in an HCCI engine fueled with a mixture of natural gas and diesel

Energy Conversion and Management ◽

10.1016/j.enconman.2015.08.014 ◽

2015 ◽

Vol 105 ◽

pp. 498-508 ◽

Cited By ~ 24

Author(s):

Samad Jafarmadar ◽

Peyman Nemati ◽

Rana Khodaie

Keyword(s):

Natural Gas ◽

Exhaust Gas Recirculation ◽

Exhaust Gas ◽

Hcci Engine ◽

Multidimensional Modeling ◽

Gas Recirculation

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Hydrogen enrichment: A way to maintain combustion stability in a natural gas fuelled engine with exhaust gas recirculation, the potential of fuel reforming

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1243/0954407011525737 ◽

2001 ◽

Vol 215 (3) ◽

pp. 405-418 ◽

Cited By ~ 58

Author(s):

S. Allenby ◽

W-C. Chang ◽

A. Megaritis ◽

M. L. Wyszyński

Keyword(s):

Natural Gas ◽

Exhaust Gas Recirculation ◽

Combustion Stability ◽

Exhaust Gas ◽

Fuel Reforming ◽

Rapid Reduction ◽

Indicated Mean Effective Pressure ◽

Hydrogen Enrichment ◽

Gas Recirculation ◽

Operating Points

An experimental study was carried out to evaluate the potential of hydrogen enrichment to increase the tolerance of a stoichiometrically fuelled natural gas engine to high levels of dilution by exhaust gas recirculation (EGR). This provides significant gains in terms of exhaust emissions without the rapid reduction in combustion stability typically seen when applying EGR to a methane-fuelled engine. Presented results give the envelope of benefits from hydrogen enrichment. In parallel, the performance of a catalytic exhaust gas reforming reactor was investigated in order that it could be used as an onboard source of hydrogen-rich EGR. It was shown that sufficient hydrogen was generated with currently available prototype catalysts to allow the engine, at the operating points considered, to tolerate up to 25 per cent EGR, while maintaining a coefficient of variability of indicated mean effective pressure below 5 per cent. This level of EGR gives a reduction in NO emissions greater than 80 per cent in all test cases.

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