Experimental investigation of methane-enriched biogas in a single cylinder diesel engine by the dual fuel mode

ABSTRACT

In this experimental work characteristic such as performance, combustion and emission of a single cylinder, four-stroke constant speed, direct injection, water-cooled diesel engine is investigated. The engine is operated by dual fuel mode using methane-enriched biogas (88.10%-CH₄ + 11.89%-CO₂) obtained from the food waste. Biogas (BG) is inducted into the engine at intake manifold with various mixtures like BG20, BG30 and BG40 mixed with air (i.e. BG40-40% of CH₄ by mass respectively) at actual injection timing of 27.5° before top dead centre (bTDC) for different loads. The performance, combustion and emission characteristics of the engine operated by dual fuel mode were experimentally investigated, and compared with respect to diesel. By observing the experimental results, BG40 was optimized on the basis of lesser emissions and improved performance. BG40 showed lesser brake thermal efficiency and higher brake specific energy consumption than BG20 and BG30 for all loads. On the other hand, BG40 showed lower BTE by 15.5% and 15.62% compared to diesel at 3/4^th and full load. Whereas the cylinder peak pressure for BG40 is higher than diesel by 5.36% and the net heat release rate is 14.9% higher than the diesel at full load. BG40 emitted higher carbon monoxide (CO) emissions than diesel by 5% at full load. The nitrogen oxide (NOx) emission for BG40 was lesser by 26.60% than diesel at full load, whereas the soot emission was 22.71% lower than diesel at full load respectively.

KEYWORDS:

• Biogas
• combustion
• energy
• emission
• injection timing

Acknowledgments

The authors would like to express gratitude to Mangalore city corporation (MCC), Karnataka, India for providing biogas and department of mechanical engineering NITK surathkal, Karnataka, India to conduct experiments.

Nomenclature

bTDC	=	before top dead centre
BTE	=	Brake thermal efficiency
BP	=	Brake power
BG	=	Biogas
CI	=	Compression Ignition
CO	=	Carbon monoxide
DAQ	=	Data acquisition system
EGA	=	Exhaust gas analyzer
NOx	=	Nitrogen oxide
NHRR	=	Net heat release rate

Additional information

Notes on contributors

Jagadish C

Jagadish C received M.Tech degree in Thermal engineering from National Institute of technology Karnataka (NITK), Surathkal, India, in 2012 and is currently a research scholar at National Institute of technology Karnataka (NITK), Surathkal, India. His research interest includes internal combustion engines, alternative fuels, combustion, renewable energy and heat transfer.

Veershetty Gumtapure

Veershetty Gumtapure is an assistant professor in National Institute of Technology Karnataka (NITK), Surathkal, India. He received his B.E degree in Automobile engineering in 2004 and earned his M.Tech and Ph.D. degrees from Indian Institute of Technology Madras (IITM), India in 2007 and 2014 respectively. His major interests are renewable energy, solar energy conversion, automobile engineering, heat transfer and CFD.