Characterization and Evaluation of Methane Oxidation Catalysts for Dual-Fuel Diesel and Natural Gas Engines

Both spark ignition (SI) natural gas engines and compression ignition (CI) dual fuel (DF) engines suffer from knocking when the unburnt mixture ignites spontaneously prior to the flame front arrival. In this study, a parametric investigation is performed on the knocking performance of these two engine types by using the GT-Power software. An SI natural gas engine and a DF engine are modelled by employing a two-zone zero-dimensional combustion model, which uses Wiebe function to determine the combustion rate and provides adequate prediction of the unburnt zone temperature, which is crucial for the knocking prediction. The developed models are validated against experimentally measured parameters and are subsequently used for performing parametric investigations. The derived results are analysed to quantify the effect of the compression ratio, air-fuel equivalence ratio and ignition timing on both engines as well as the effect of pilot fuel energy proportion on the DF engine. The results demonstrate that the compression ratio of the investigated SI and DF engines must be limited to 11 and 16.5, respectively, for avoiding knocking occurrence. The ignition timing for the SI and the DF engines must be controlled after −38°CA and 3°CA, respectively. A higher pilot fuel energy proportion between 5% and 15% results in increasing the knocking tendency and intensity for the DF Engine at high loads. This study results in better insights on the impacts of the investigated engine design and operating settings for natural gas (NG)-fuelled engines, thus it can provide useful support for obtaining the optimal settings targeting a desired combustion behaviour and engine performance while attenuating the knocking tendency.

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Desulfation of Pd-based Oxidation Catalysts for Lean-burn Natural Gas and Dual-fuel Applications

SAE International Journal of Engines ◽

10.4271/2015-01-0991 ◽

2015 ◽

Vol 8 (4) ◽

pp. 1472-1477 ◽

Cited By ~ 14

Author(s):

Nathan Ottinger ◽

Rebecca Veele ◽

Yuanzhou Xi ◽

Z. Gerald Liu

Keyword(s):

Natural Gas ◽

Dual Fuel ◽

Oxidation Catalysts ◽

Lean Burn

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Cyclic Combustion Variations in Dual Fuel Partially Premixed Pilot-Ignited Natural Gas Engines

Journal of Energy Resources Technology ◽

10.1115/1.4024855 ◽

2013 ◽

Vol 136 (1) ◽

Cited By ~ 15

Author(s):

K. K. Srinivasan ◽

S. R. Krishnan ◽

Y. Qi

Keyword(s):

Natural Gas ◽

Dual Fuel ◽

Nox Emissions ◽

Natural Gas Engines ◽

Percentage Points ◽

Combustion Modes ◽

Diesel Injection ◽

Cyclic Variations ◽

Partially Premixed ◽

Dual Fueling

Dual fuel pilot-ignited natural gas engines are identified as an efficient and viable alternative to conventional diesel engines. This paper examines cyclic combustion fluctuations in conventional dual fuel and in dual fuel partially premixed combustion (PPC). Conventional dual fueling with 95% (energy basis) natural gas (NG) substitution reduces NOx emissions by almost 90% relative to neat diesel operation; however, this is accompanied by 98% increase in HC emissions, 10 percentage points reduction in fuel conversion efficiency (FCE) and 12 percentage points increase in COVimep. Dual fuel PPC is achieved by appropriately timed injection of a small amount of diesel fuel (2–3% on an energy basis) to ignite a premixed natural gas–air mixture to attain very low NOx emissions (less than 0.2 g/kWh). Cyclic variations in both combustion modes were analyzed by observing the cyclic fluctuations in start of combustion (SOC), peak cylinder pressures (Pmax), combustion phasing (Ca50), and the separation between the diesel injection event and Ca50 (termed “relative combustion phasing”). For conventional dual fueling, as NG substitution increases, Pmax decreases, SOC and Ca50 are delayed, and cyclic variations increase. For dual fuel PPC, as diesel injection timing is advanced from 20 deg to 60 deg BTDC, Pmax is observed to increase and reach a maximum at 40 deg BTDC and then decrease with further pilot injection advance to 60 deg BTDC, the Ca50 is progressively phased closer to TDC with injection advance from 20 deg to 40 deg BTDC, and is then retarded away from TDC with further injection advance to 60 deg BTDC. For both combustion modes, cyclic variations were characterized by alternating slow and fast burn cycles, especially at high NG substitutions and advanced injection timings. Finally, heat release return maps were analyzed to demonstrate thermal management strategies as an effective tool to mitigate cyclic combustion variations, especially in dual fuel PPC.

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A Machine Learning Modeling Approach for High Pressure Direct Injection Dual Fuel Compressed Natural Gas Engines

10.4271/2020-01-2017 ◽

2020 ◽

Author(s):

Michael Karpinski-Leydier ◽

Ryozo Nagamune ◽

Patrick Kirchen

Keyword(s):

Machine Learning ◽

High Pressure ◽

Natural Gas ◽

Direct Injection ◽

Dual Fuel ◽

Compressed Natural Gas ◽

Natural Gas Engines ◽

Modeling Approach

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Impact of Oxidation Catalysts on Exhaust NO2/NOx Ratio from Lean-Burn Natural Gas Engines

Journal of the Air & Waste Management Association ◽

10.3155/1047-3289.60.7.867 ◽

2010 ◽

Vol 60 (7) ◽

pp. 867-874 ◽

Cited By ~ 18

Author(s):

Daniel B. Olsen ◽

Morgan Kohls ◽

Gregg Arney

Keyword(s):

Natural Gas ◽

Oxidation Catalysts ◽

Lean Burn ◽

Natural Gas Engines

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Cyclic Combustion Variations in Dual Fuel Partially Premixed Pilot-Ignited Natural Gas Engines

ASME 2012 Internal Combustion Engine Division Spring Technical Conference ◽

10.1115/ices2012-81145 ◽

2012 ◽

Cited By ~ 1

Author(s):

K. K. Srinivasan ◽

S. R. Krishnan ◽

Y. Qi

Keyword(s):

Natural Gas ◽

Dual Fuel ◽

Nox Emissions ◽

Natural Gas Engines ◽

Percentage Points ◽

Combustion Modes ◽

Diesel Injection ◽

Cyclic Variations ◽

Partially Premixed ◽

Dual Fueling

Dual fuel pilot ignited natural gas engines are identified as an efficient and viable alternative to conventional diesel engines. This paper examines cyclic combustion fluctuations in conventional dual fuel and in dual fuel partially premixed low temperature combustion (LTC) at 1700 rev/min and 6 bar brake mean effective pressure (bmep). Conventional dual fueling with 95% (energy basis) natural gas (NG) substitution reduces NOx emissions by almost 90%t relative to straight diesel operation; however, this is accompanied by 98% increase in HC emissions, 10 percentage points reduction in fuel conversion efficiency (FCE) and 12 percentage points increase in COVimep. Dual fuel LTC is achieved by injection of a small amount of diesel fuel (2–3 percent on an energy basis) to ignite a premixed natural gas–air mixture to attain very low NOx emissions (less than 0.2 g/kWh). Cyclic variations in both combustion modes were analyzed by observing the cyclic fluctuations in start of combustion (SOC), peak cylinder pressures (Pmax), combustion phasing (Ca50), and the separation between the diesel injection event and Ca50 (termed “relative combustion phasing”). For conventional dual fueling, as % NG increases, Pmax decreases, SOC and Ca50 are delayed, and cyclic variations increase. For dual fuel LTC, as diesel injection timing is advanced from 20° to 60°BTDC, the relative combustion phasing is identified as an important combustion parameter along with SoC, Pmax, and CaPmax. For both combustion modes, cyclic variations were characterized by alternating slow and fast burn cycles, especially at high %NG and advanced injection timings. Finally, heat release return maps were analyzed to demonstrate thermal management strategies as an effective tool to mitigate cyclic combustion variations, especially in dual fuel LTC.

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