Development of HCNG Blended Fuel Engine with Control of NOx Emissions

Abstract

With increasing concern about energy shortage and environmental protection, research on reducing exhaust emissions, reducing fuel consumption, reducing engine noise and increasing specific outputs has become the major researching aspect in combustion and engine development. Alternative fuels such as CNG, HCNG, LPG, LNG, Bio-Diesel, Biogas, Hydrogen, Ethanol, Methanol, Di-Methyl Ether, Producer gas, P-series have been tried worldwide. Hydrogen as a future fuel for IC engines is also being considered. But several obstacles have to overcome before commercialization of Hydrogen as an IC engine fuel for automotive sector. Hydrogen and CNG blends (HCNG) may be considered as an automotive fuel without any major modification in the existing CNG engine and infrastructure.

A strategy has been worked out for converting the optimised CNG engine to run on HCNG. The testing is carried out for the neat CNG and 5% blends of Hydrogen by volume with CNG. It is observed in the experimental work that the HCNG engines are more superior to CNG engines from fuel economy, power output and emission compliance point of view. The power improvement of 3 to 4%, torque improvement of 3% and fuel consumption reduction of 4% is observed in HCNG engine than the neat CNG engine.

The HCNG engine increases the H/C ratio of the fuel, which drastically reduces the carbon based emissions such as CO, CO2 and HC. To increase the flame speed of HCNG engines, the ignition timing needs to be retarded; this results in reduction of NOx emissions. The HCNG reduced CO emissions by 40 to 50%, NMHC emissions by 45% and NOx emissions by 20 to 30% than the neat CNG operation. It shows that the blended HCNG fuel is more environmental friendly. It is important to note that 5% blends of hydrogen by volume with CNG the phenomenon of hydrogen embrittlement does not occur with respect to engine components, hence no major change is anticipated in fuel system and engine components. This research work is undertaken to demonstrate the viability of HCNG as an automotive fuel at Powertrain Engineering laboratory ARAI, Pune, India. This paper explains how CNG is the best route to ensure an early entry of hydrogen fuel into our energy infrastructure.