25–26 Jun 2026
''Vasil Levski'' National Military University
Europe/Sofia timezone

COMPARATIVE ANALYSIS OF EFFICIENCY AND ECONOMIC PERFORMANCE OF A DUAL-FUEL DIESEL ENGINE FUELED WITH COMPRESSED NATURAL GAS AND HYDROGEN

Not scheduled
20m
''Vasil Levski'' National Military University

''Vasil Levski'' National Military University

Veliko Tarnovo, Bulgaria
Paper – Oral Presentation Sustainable Energy Engineering and Applications

Speaker

Atanasi Tashev (Department of Transport and Aircraft Equipment and Technologies, Faculty of Mechanical Engineering, Technical University of Sofia, Plovdiv Branch, 25 Tsanko Dyustabanov Street, 4000 Plovdiv , Bulgaria)

Description

This study presents a comparative experimental analysis of the thermodynamic and economic performance of a compression ignition engine operating in conventional diesel mode and in dual-fuel mode with compressed natural gas and hydrogen. The investigation evaluates the influence of gaseous fuel addition on fuel consumption, brake specific fuel consumption, thermal efficiency, and cost of energy production under identical operating conditions. Experimental tests were conducted on a single-cylinder diesel engine at constant engine speed of 2000 min⁻¹ and variable load, using both fixed (K = 20%) and maximum gas substitution ratios. The performance of the engine was assessed based on measured fuel consumption parameters and calculated efficiency indicators. An economic evaluation was also performed using representative fuel prices. The results show that conventional diesel operation achieves the highest thermal efficiency, reaching approximately 29.5% at medium load, compared to about 28 – 29% for hydrogen and 26 – 27% for compressed natural gas. From an economic perspective, compressed natural gas provides the lowest cost of energy production, reaching values as low as approximately 0.50 €/kWh, followed by diesel at around 0.65 – 0.70 €/kWh, while hydrogen results in the highest cost, exceeding 1.0 €/kWh at low loads due to its higher fuel price. The results highlight a clear trade-off between efficiency and cost. While diesel operation remains the most efficient, and compressed natural gas is the most economically favorable option, hydrogen demonstrates improved performance compared to methane and offers significant environmental benefits.

Authors

Atanasi Tashev (Department of Transport and Aircraft Equipment and Technologies, Faculty of Mechanical Engineering, Technical University of Sofia, Plovdiv Branch, 25 Tsanko Dyustabanov Street, 4000 Plovdiv , Bulgaria) Prof. Evgeni Dimitrov

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