Study of the main reactions involved in reforming of exhaust gas recirculation (REGR) in gasoline engines

Gomes, S. Rijo; Bion, Nicolas; Blanchard, G.; Rousseau, Séverine; Duprez, Daniel; Epron, Florence

doi:10.1039/c1ra00003a

Cited by 10 publications

(7 citation statements)

References 24 publications

(41 reference statements)

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“…Heat consumed in the reaction increases the enthalpy of the products relative to the reactants and can therefore be used as a form of waste-heat recovery. 19 Previous works have demonstrated the potential of generating hydrogen-rich syngas from fuel onboard the vehicle using various processes (both catalyzed and un-catalyzed) 14,15,18,[20][21][22][23]…”

Section: Practical Engine Knockmentioning

confidence: 99%

Quantification of knock benefits from reformate and cooled exhaust gas recirculation using a Livengood–Wu approach with detailed chemical kinetics

Marsh

Voice

2016

International Journal of Engine Research

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In this work, a simple methodology was implemented to predict the onset of knock in spark-ignition engines and quantify the benefits of two practical knock mitigation strategies: cooled exhaust gas recirculation and syngas blending. Based on the results of this study, both cooled exhaust gas recirculation and the presence of syngas constituents in the end-gas substantially improved the knock-limited compression ratio of the engine. At constant load, 25% exhaust gas recirculation increased the knock-limited compression ratio from 9.0 to 10.8:1 (0.07 compression ratio per 1% exhaust gas recirculation) due to lower end-gas temperature and reactant (fuel and oxygen) concentrations. At exhaust gas recirculation rates above 43%, higher intake temperature outweighed the benefits of lower end-gas reactant concentration. At constant intake temperature, cooled exhaust gas recirculation was significantly more effective at all exhaust gas recirculation rates (0.10 compression ratio per 1% exhaust gas recirculation), and no diminishing returns or optimum was observed. Both hydrogen and carbon monoxide were also predicted to improve knock by reducing end-gas reactivity, likely through the conversion of high-reactivity hydroxy-radicals to less reactive peroxy-radicals. Hydrogen increased the knock-limited compression ratio by 1.1 per volume percent added at constant energy content. Carbon monoxide was less effective, increasing the knock-limited compression ratio by 0.38 per volume percent added. Combining 25% cooled exhaust gas recirculation with reformate produced from rich combustion at an equivalence ratio of 1.3 resulted in a predicted increase in the knock-limited compression ratio of 3.5, which agreed well with the published experimental engine data. The results show the extent to which syngas blending and cooled exhaust gas recirculation each contribute separately to knock mitigation and demonstrate that both can be effective knock mitigation strategies. Together, these solutions have the potential to increase the compression ratio and efficiency of spark-ignition engines.

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Section: Practical Engine Knockmentioning

confidence: 99%

Quantification of knock benefits from reformate and cooled exhaust gas recirculation using a Livengood–Wu approach with detailed chemical kinetics

Marsh

Voice

2016

International Journal of Engine Research

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“…During the reaction in the REGR conditions, methane may be produced by isooctane decomposition or hydrogenolysis or by methanation of CO or CO2 [13], and then consumed by steam or dry reforming. All these steps were studied in details in [13] and it was demonstrated that the low amount of methane is due to the limitation of its formation, isooctane decomposition and hydrogenolysis and CO2 methanation being strongly disfavored in the reaction conditions in the presence of a Rh-based catalyst. On this type of catalyst, methane is nearly exclusively produced by CO hydrogenation.…”

Section: Catalytic Performancesmentioning

confidence: 99%

“…the study of the steam reforming, dry reforming and REGR reactions separately, in various conditions of temperature and contact time and (ii) on the conversion of methane and its production by CO or CO2 methanation, or by C8H18 hydrogenolysis or decomposition, enabled us to propose a reaction scheme in 3 successive steps for isooctane conversion in REGR conditions, i.e. the reforming of isooctane in the presence of water, carbon dioxide and oxygen [13], yielding H2 and CO2, CO and CH4:…”

Section: Introductionmentioning

confidence: 99%

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Hydrogen production from hydrocarbons over Rh supported on Ce-based oxides for automotive applications

Gomes

Bion

Duprez

et al. 2016

Applied Catalysis B: Environmental

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“…Thermodynamic and experimental studies of the REGR reactions have shown that precious metal catalysts, e.g. rhodium on zirconia, 14,15 exhibit high activity with yields close to equilibrium at temperatures typical of the gasoline engine exhaust. A recent experimental study 1 using hydrogen and CO addition to conventional EGR highlights the potential benets that REGR can offer to the GDI engine, with simultaneous reductions in NO x , PM and CO, only slightly increased HCs, and increased engine and total system thermal efficiency.…”

Section: Introductionmentioning

confidence: 99%

Thermochemical recovery technology for improved modern engine fuel economy – part 1: analysis of a prototype exhaust gas fuel reformer

et al. 2015

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Exhaust gas fuel reforming has the potential to improve the thermal efficiency of internal combustion engines, as well as simultaneously reduce gaseous and particulate emissions. This thermochemical energy recovery technique aims to reclaim exhaust energy from the high temperature engine exhaust stream to drive catalytic endothermic fuel reforming reactions; these convert hydrocarbon fuel to hydrogen-rich reformate. The reformate is recycled back to the engine as Reformed Exhaust Gas Recirculation (REGR), which provides a source of hydrogen to enhance the engine combustion process and enable high levels of charge dilution; this process is especially promising for modern gasoline direct injection (GDI) engines. This paper presents a full-scale prototype gasoline reformer integrated with a multi-cylinder GDI engine. Performance is assessed in terms of the reformate composition, the temperature distribution across the catalyst, the reforming process (fuel conversion) efficiency and the amount of exhaust heat recovery achieved.

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Study of the main reactions involved in reforming of exhaust gas recirculation (REGR) in gasoline engines

Cited by 10 publications

References 24 publications

Quantification of knock benefits from reformate and cooled exhaust gas recirculation using a Livengood–Wu approach with detailed chemical kinetics

Quantification of knock benefits from reformate and cooled exhaust gas recirculation using a Livengood–Wu approach with detailed chemical kinetics

Hydrogen production from hydrocarbons over Rh supported on Ce-based oxides for automotive applications

Thermochemical recovery technology for improved modern engine fuel economy – part 1: analysis of a prototype exhaust gas fuel reformer

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