Optimal fuel blends for natural gas engines

• Research unit: COST
• Project number: C16.0066

Key words (English)

Natural gas engines; NOx and CO2 emissions; lean limit; methane slip; combustion chemistry; Direct Numerical Simulation; RANS; engine modeling

Research programs (English)

COST-Action CM1404 - SMARTCAT: CHEMISTRY OF SMART ENERGY CARRIERS AND TECHNOLOGIES

Short description (English)

Concerns about greenhouse gases (GHG), air pollutants, and shortage of petroleum-based fuels have led to the development of new combustion concepts and the search for alternative fuels. Natural gas (NG) consisting primarily of methane is regarded as one of the most promising alternative fuels, and NG engines enjoy increasing market share. The challenges for advanced Otto-gas-engines result from the trade-off between stable combustion under ultra lean conditions and minimal nitrogen oxide emissions on one hand, and high thermodynamic efficiency and knock suppression on the other. Engine efficiency at lean-burn operation increases and pollutant emissions decrease as the equivalence ratio decreases. At some point the “lean limit” is reached where the burning rate becomes too slow for complete combustion. Even before the limit is reached, there is a small range of equivalence ratio for which intermittent misfiring results in increased cyclic variability and higher exhaust emission levels. An emerging concern for gas engines is the “methane slip”, the relatively high engine-out emissions of methane, a highly-relevant GHG with a global warming potential about 25 times larger than carbon dioxide. The aim of the proposed work is to examine in a systematic way to what extent the conflicting requirements can be met by adding gaseous species to methane so that engines can be operated stably and reliably at the lean limit with minimal methane slip and pollutant emissions.

Further information (English)

Full name of research-institution/enterprise: Swiss Federal Institute of Technology ETH Aerothermochemistry and Combustion Systems Laboratory LAV

Partners and International Organizations (English)

AT; BE; BG; HR; CY; CZ; DK; FR; DE; EL; HU; IE; IL; IT; LT; NL; NO; PT; RS; SI; ES; SE; TR; UK

Abstract (English)

See short description

References in databases (English)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C16.0066