Performance and emission characteristics of compression ignition (CI) engine with dual fuel operation (diesel + compressed natural gas (CNG))

The main objective of this work is to study the performance and emission characteristics ofcompression ignition (CI) engine using compressed natural gas (CNG) for the following conditions. (i) At constant speed by varying injection pressure and load (ii) Dual fuel combustion phenomenon. The conventional fuels like petrol and diesel for internal combustion engines are getting exhausted at an alarming rate, due to tremendous increase in the vehicular population. Further, these fuels cause serious environmental problems as they release toxic gases into the atmosphere at high temperatures and concentrations. Some of the pollutants released by the engines are un-burnt hydro carbons (UBHC), CO, NOx, smoke and particulate matter. In view of this and many other related issues, these fuels will have to be replaced by alternative and eco-friendly fuels. A 4-stroke, single-cylinder, vertical, stationary diesel engine has been considered for the purpose of experimentation. It is modified suitably to run on the dual fuel mode. CNG gas-air mixer is incorporated on the intake side of the engine. The fuel injection system is also altered so that it injects only the pilot fuel. The engine performance is better on CNG compared to pure diesel up to engine loads of about 75.67%.   Key words: Dual-fuel, emissions, compressed natural gas (CNG), performance