0
Research Papers: Energy Systems Analysis

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

[+] Author and Article Information
K. K. Srinivasan

Assistant Professor
Mississippi State University,
Mississippi State, MS 39762
e-mail: srinivasan@me.msstate.edu

S. R. Krishnan

Assistant Professor
Mississippi State University,
Mississippi State, MS 39762
e-mail: krishnan@me.msstate.edu

Y. Qi

Caterpillar Inc.,
Tech Center, Bldg F-724,
14009 Old Galena Rd.,
Mossville IL 61552-1875
e-mail: Qi_Yongli@cat.com

1Corresponding author.

Contributed by the Advanced Energy Systems Division of ASME for publication in the JOURNAL OF ENERGY RESOURCES TECHNOLOGY. Manuscript received July 25, 2012; final manuscript received June 4, 2013; published online September 12, 2013. Assoc. Editor: Timothy J. Jacobs.

J. Energy Resour. Technol 136(1), 012003 (Sep 12, 2013) (10 pages) Paper No: JERT-12-1171; doi: 10.1115/1.4024855 History: Received July 25, 2012; Revised June 04, 2013

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.

FIGURES IN THIS ARTICLE
<>
Copyright © 2014 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 3

Pmax versus CaPmax for conventional dual fuel combustion

Grahic Jump Location
Fig. 4

Pmax versus Ca50 for conventional dual fuel combustion

Grahic Jump Location
Fig. 2

Specific NOx and HC emissions, COVimep, FCE and Combustion Efficiency versus relative combustion phasing for conventional dual fuel combustion

Grahic Jump Location
Fig. 5

Ca50 versus SOC for conventional dual fuel combustion

Grahic Jump Location
Fig. 6

Normalized first-order heat release return maps at various NG substitutions for conventional dual fuel combustion: (a) 0% NG substitution (neat diesel), (b) 50% NG substitution, (c) 85% NG substitution, and (d) 95% NG substitution

Grahic Jump Location
Fig. 7

Specific NOx and HC emissions, COVimep, FCE and Combustion Efficiency versus relative combustion phasing for dual fuel PPC

Grahic Jump Location
Fig. 8

Ca50 versus SOC for dual fuel PPC

Grahic Jump Location
Fig. 1

Progression of dual fuel combustion strategies in achieving high fuel conversion efficiencies and low engine-out NOx emissions. In this figure, Refs. [5,10,11] use BSEC (MJ/kWh) and BSNOx (g/kWh) and Refs. [14,15] use ISEC (MJ/kWh) and ISNOx (g/kWh).

Grahic Jump Location
Fig. 9

Pmax and Ca50 versus CaPmax for dual fuel PPC

Grahic Jump Location
Fig. 10

Pmax versus Ca50 for dual fuel LTC

Grahic Jump Location
Fig. 11

Pmax, HC, and FCE vs. relative combustion phasing for dual fuel LTC

Grahic Jump Location
Fig. 12

Normalized heat release return map for dual fuel LTC with 20 deg BTDC SOI and Tin = 75 °C and 105 °C

Grahic Jump Location
Fig. 13

Normalized heat release return map for dual fuel LTC with 40 deg BTDC SOI and Tin = 75 °C and 105 °C

Grahic Jump Location
Fig. 14

Normalized heat release return map for dual fuel LTC with 60 deg BTDC SOI and Tin = 75 °C and 105 °C

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In