Oxidation Catalysts for Natural Gas Engine Operating under HCCI or SI Conditions

Williams, Shazam; Hu, Linjie; Nakazono, Tohru; Ohtsubo, Hiroyuki; Uchida, Miwa

doi:10.4271/2008-01-0807

Cited by 24 publications

(6 citation statements)

References 21 publications

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“…2 is about 400 uC. This peak temperature is considered low compared with that of the SI mode for which the exhaust temperature is generally higher than 400 uC [22]. Higher HC and CO emissions are observed at lower T exh in Figs 2(a) and (b).…”

Section: Resultsmentioning

confidence: 84%

“…2 depends on the operating conditions in which the HCCI engine can run without exceeding the knock or misfiring limit. The HCCI exhaust temperature can be as low as 120 uC [22]. The peak T exh among 304 HCCI data points in Fig.…”

Section: Resultsmentioning

confidence: 97%

“…Passive systems, however, are completely dependent on the temperature and flowrate of the exhaust gases. Since HCCI typically has a low exhaust temperature, as low as 120 uC [22], the HC and CO abatement by oxidation catalysts remains an important concern in HCCI engines. This could limit the desirable operating range of HCCI engines and also the low HCCI exhaust temperature provides little energy for turbocharging, which is often used to extend the HCCI operating range for high loads [23].…”

Section: Introductionmentioning

confidence: 99%

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Experimental study of exhaust temperature variation in a homogeneous charge compression ignition engine

Shahbakhti¹,

Ghazimirsaied

Koch

2010

Proceedings of the Institution of Mechanical Engineers, Part D:

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Homogeneous charge compression ignition (HCCI) engines have low nitrogen oxide and particulate matter engine-out emissions but have higher unburned hydrocarbon and carbon monoxide emissions than the conventional spark ignition (SI) and diesel engines do. Only for sufficiently high exhaust gas temperatures can an exhaust after-treatment be used; thus a low exhaust gas temperature in certain operating conditions can limit the operating range in HCCI engines. The influences of the engine conditions on the exhaust gas temperature in a single-cylinder experimental engine are investigated at 340 steady state operating points. The variation in the exhaust gas temperature is also studied under transient conditions and during mode switching between SI and HCCI combustion. For the conditions tested, a significant number of data have an exhaust gas temperature below 300°C which is below the light-off temperature of typical catalytic converters on the market. Three different categories of engine variables are recognized and classified by how the exhaust temperature is affected by changing that variable. The first category is defined as the primary variables (e.g. the intake pressure and the fuel octane number) for which the location of ignition timing is the dominant factor in influencing the exhaust temperature. The other groups include compounding variables such as the engine speed and opposing variables such as the intake temperature, the coolant temperature, and the equivalence ratio. In addition, experimental results show that the exhaust temperature for HCCI engines is not strongly dependent on the engine load, unlike that for SI engines where the engine load is a main factor in determining the exhaust temperature.

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Section: Resultsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Experimental study of exhaust temperature variation in a homogeneous charge compression ignition engine

Shahbakhti¹,

Ghazimirsaied

Koch

2010

Proceedings of the Institution of Mechanical Engineers, Part D:

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“…A decrease in the activity of a palladium catalyst because of existence of water and catalytic poisons was proved in paper [8]. Thus, after aging, a catalyst cannot ignite methane gas at temperature of 400 °C, while a fresh catalyst provided 80 % conversion of methane at the same temperature.…”

Section: Literature Review and Problem Statementmentioning

confidence: 96%

Research into methane oxidation on oxide catalyst of the applied type

Попович

Soloviev²,

Suvorin

2017

EEJET

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“…Platinum based oxidation catalysts have low performance in catalyzing HCs, especially lower alkanes at low temperatures [146], [147], [148]. However, oxidation of CO is well established [149] and literature has shown high conversion efficiencies (>90%) at temperatures of 200 °C and lower.…”

Section: Fuel Quality Effect On the Performancementioning

confidence: 99%

A Framework for Energy Optimization of Small, Two-Stroke, Natural Gas Engines for Combined Heat and Power Applications

Darzi¹

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A Framework for Energy Optimization of Small, Two-Stroke, Natural Gas Engines for Combined Heat and Power Applications Mahdi Darzi This research was focused on the development of a framework for the energy optimization a natural gas engine for small combined heat and power (CHP) applications operating with lowpressure natural gas (NG) available at homes. The required targets of the ARPA-E GENSETS program for 1 kW electric power generation and previous GENSETS simulation at West Virginia University, suggested a design space for the engine which is currently dominated by simple twostroke designs. Hence this research focused on screening, modeling, and experimentally evaluation of cost-effective technologies to achieve a system design that maximized thermal efficiency and utilization factor, while reducing emissions. A baseline engine was selected which started with 8% brake thermal efficiency (BTE) on natural gas operation. By implementing intake and exhaust optimization BTE increased up to around 12% and with head design optimization and exhaust backpressure, the engine reached 15% BTE. Though the initial optimization methods almost doubled efficiency, it was realized that further increases in BTE must be achieved for a commercially competitive design. The engine was redesigned to utilize modified porting for enhanced breathing and scavenging and a method to deploy low-pressure direct injection (LPDI) was developed. With these enhancements, BTE increased to around 24%. A second round of optimization was performed then, by modeling the whole system in a 1D platform and using a genetic algorithm and experimental data to further optimize scavenging which increased the efficiency up to around 26%. Finally, a 3D computational fluid dynamics (CFD) was developed to investigate the stratification effects of LPDI and determine the optimal spark plug location. This effort increased the BTE to around 27.5%. To assess issues with commercial deployment, three different NG compositions and propane operation were investigated. With an energy balance and exergy distribution analysis for each fuel, fuel quality effects on the CHP system performance were determined. At the end, with combination literature review, experiments, 1D and 3D simulations, a framework for optimization of micro-CHP systems operating on gaseous fuels was developed that can serve industry to highlight methods that can more than triple brake thermal efficiency of small two-stroke engines while improving the energy distribution for CHP systems. iii Acknowledgment Special thanks to Dr. Johnson for his support and mentorship throughout my PhD program. I thank my dedicated PhD committee members for their guidance and valuable feedback to improve this dissertation. I would like to thank Mr.

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Oxidation Catalysts for Natural Gas Engine Operating under HCCI or SI Conditions

Cited by 24 publications

References 21 publications

Experimental study of exhaust temperature variation in a homogeneous charge compression ignition engine

Experimental study of exhaust temperature variation in a homogeneous charge compression ignition engine

Research into methane oxidation on oxide catalyst of the applied type

A Framework for Energy Optimization of Small, Two-Stroke, Natural Gas Engines for Combined Heat and Power Applications

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