Indian Railways Launches CNG Dual-Fuel DEMUs
India’s Minister for Railways, Suresh Prabhu, has flagged off two more Compressed Natural Gas (CNG) powered trains. The trains are Diesel Electric Multiple Units (DEMU) which have been converted to dual-fuel (Diesel, CNG) as part of a project by Indian Railways Organisation for Alternate Fuels (IROAF) to deliver technology that reduces the environmental impact of Indian Rail operations.
IROAF has already commissioned other CNG trains and plans many more.
The technology is based on “Fumigation” in which natural gas enters the engine with normal combustion air through the air filter, before the turbo charger. A significantly reduced amount of diesel fuel continues into the engine, which serves as a pilot ignition source for the natural gas. The control system maintains a proper balance of natural gas, diesel and air to meet the engine’s power requirements. About 20% substitution of diesel can be achieved by this method.
Benefits include measureable reductions of carbon monoxide, carbon dioxide, nitrogen oxide, non-methane hydrocarbon, and zero particulate matter. Additionally, the use of CNG is not only economical but also leads to a lesser degree of wear and tear of engine parts.
The conversions were carried out by Integral Coach Factory, Chennai, a Production Unit under the Ministry of Railways.