Development of HCNG Blended Fuel Engine with Control of NOx Emissions

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 developed 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 carbureted engines from fuel economy, power output and emission compliance point of view. The power improvement of 11% and fuel consumption reduction of 8% is observed in HCNG engine than the CNG engine. The addition of hydrogen into natural gas increases the burning velocity of mixture, shortening the combustion duration, increasing the cylinder gas temperature, and this increases the effective thermal efficiency compared to that of natural gas engine under the same lean mixture condition. 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. 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 anticipa- ted in fuel system and engine components. Moreover, it improves the engine efficiency, which lowers fuel consumption and hydrocarbon emissions. The research work is undertaken to demonstrate the viability of HCNG as an automotive fuel. This paper explains how CNG is the best route to ensure an early entry of hydrogen fuel into our energy infrastructure. This research work is carried out at Alternative fuel engine development lab, ARAI, Pune, India.