Session: 08-01: Poster Session

Paper Number: 149661

149661 - Dibutyl Oxymethylene Ether(b-1-B) Ignited Natural Gas Combustion in a Heavy-Duty Single-Cylinder Ci Engine. 

Abstract: 

Dibutyl oxymethylene Ether(B-1-B) Ignited Natural gas Combustion in a Heavy-Duty Single-Cylinder CI engine.

Yamini Baskara Babu, Hariraja Thothadri, Stephen Mundy, Justin Gray, Abhinandhan Narayanan, Sundar Rajan Krishnan, Kalyan Kumar Srinivasan

Diesel remains as the primary fuel for heavy-duty vehicles despite the intransigent soot-NOx trade-off and increasingly restrictive emissions standards. As an alternative, dual-fuel combustion has been explored, with Diesel-Natural Gas RCCI (Reactivity Controlled Compression Ignition) mode showing potential for significant, simultaneous reductions in NOx and soot emissions. However, a drawback of dual-fuel RCCI combustion is higher unburned hydrocarbon (HC) and carbon monoxide (CO) emissions at low load conditions, caused by lower in-cylinder bulk gas temperatures, compromising combustion stability and fuel conversion efficiency. The concept of Spray Targeted Reactivity Stratification (STARS) using multiple injections of the high reactivity fuel (HRF) has been investigated as a solution to mitigate HC and CO emissions by maintaining higher in-cylinder bulk gas temperatures and enhancing engine stability.

 

OME (OxyMethylene Ether) has emerged as an attractive low carbon alternative to ultra-low sulphur diesel (ULSD), due to its ease of synthesis and potential to minimize soot emissions. OMEs typically exhibit a molecular structure represented by R-O-(CH2O)_n-R′, featuring oxymethylene (-CH2O-) units linked to an additional oxygen and ending with alkyl groups on either side. One notable advantage of OME is the lack of carbon-carbon bonds within its main molecular structure (discounting any C-C bonds in the alkyl groups themselves), resulting in combustion processes characterized by significantly reduced soot formation. This unique attribute presents an opportunity to eradicate the soot-NOx emissions commonly encountered in compression ignition engines.  In addition, OME fuels also present opportunities for achieving significant reductions in net carbon dioxide emissions compared to fossil diesel.

 

Previous studies from our research group have explored the potential of POMDME (polyoxymethylene di-methyl ether) and P-1-P (di-propyl oxymethylene ether) as an alternative HRF for diesel in natural gas dual-fuel combustion, and they have demonstrated favorable emissions and efficiency outcomes. The objective of the present work is to examine the combustion characteristics, engine performance, and emissions of a novel fuel B-1-B, which has higher alkyl (butyl) termination groups on either side of the -CH2O- unit, higher lower heating value (34.1MJ/kg), and higher cetane number (76.3) than P-1-P and POMDME. Research experiments were performed on a single-cylinder version of a production heavy-duty multi-cylinder engine at a constant engine speed of 1339 rev/min, under both low and high load conditions. The impact of STARS and other engine operating parameters such as HRF injection timing and duration, intake pressure, rail pressure, and exhaust gas recirculation percentage on engine performance, criteria exhaust emissions, and CO₂ emissions were characterized. A maximum pressure rise rate limit of 15 bar/CAD and a COV of IMEPg limit of 5% were imposed as limits on this heavy-duty engine, to ensure that engine operation was stable and to prevent knock. Optimal trade-offs between engine efficiency and emissions were identified and the results were compared with previous results using diesel, POMDME, and P-1-P as the HRF.

Presenting Author: Yamini Baskara Babu The University of Alabama

Presenting Author Biography: Mechanical Engineering Graduate student at The University of Alabama.

Authors:

Yamini Baskara Babu The University of Alabama
Hariraja Thothadri The University of Alabama
Stephen Mundy The University of Alabama
Justin Gray The University of Alabama
Abhinandhan Narayanan The University of Alabama
Sundar Krishnan The University of Alabama
Kalyan Srinivasan The University of Alabama