Influence of small amount of hydrogen fuel on spark-ignition engine characteristics through H-CNG fuel blend and its comparative study

ABSTRACT

An experimental study was performed on single-cylinder, four-stroke, and spark ignition engines to understand the impact of a small quantity of hydrogen fractions in CNG fuel on an engine’s performance and emission characteristics. The two blends of H-CNG in which hydrogen fuel was used were 0.20 kg/hr and 0.25 kg/hr mass flow rate at varying engine rpm. The hydrogen enrichment increases the BTE by 3.54% and 4.94%, for HCNG (0.20 kg/hr) and HCNG (0.25 kg/hr), relative to CNG operation. Similarly, the hydrogen enrichment reduces the BSFC with higher margin due to its increment in calorific value compared to CNG operation. The H-CNG fuel blend has shown severe decrement in HC, CO, CO₂, and O₂ emissions compared to gasoline and CNG fuel. However, NO_x emissions were a concern in CNG-fueled engine. The CNG-fueled engine has produced almost 32% of higher NO_x emissions than gasoline. However, adding H₂ fuel to CNG decreased NO_x emissions and brought it nearly equal to the gasoline-fueled engine emissions at overall engine rpm. Overall, from a future perspective, the H-CNG mode of operation with optimum proportion of Hydrogen-CNG can be considered a suitable fuel blend to control engine emissions without compromising engine performance of conventional SI engines.

KEYWORDS:

• Fuel
• engine emissions
• H-CNG
• CNG
• gasoline

Abbrevation

A-F	=	Air-fuel ratio
BTE	=	Brake thermal efficiency
CC	=	Combustion chamber
CI	=	Compression ignition
CO	=	Carbon monoxide
DI	=	Direct injection
EGT	=	Exhaust gas temperature
EGR	=	Exhaust gas recirculation
BSFC	=	Brake Specific Fuel Consumption
BP	=	Brake Power
FV	=	Fuel vapor
HC	=	Hydrocarbon
NA	=	Naturally aspirated
NOx	=	Oxides of nitrogen
CR	=	Compression Ratio
HCNG	=	Hydrogen-CNG
CNG	=	Compressed Natural Gas
SI	=	Spark Ignition
CO2	=	Carbon Di Oxide

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15567036.2022.2151668