Clean Development Mechanism Potential of Compression Ignition Diesel Engines Using Gaseous Fuels in Dual Fuel Mode

Abstract

The climate change problem results from the concentration of greenhouse gases (GHGs) in the atmosphere. The purpose of the Clean Development Mechanism (CDM) is to promote clean development in developing countries, and is based on the idea of emission reduction DproductionD. These reductions are DproducedD and then subtracted against a hypothetical DbaselineD of emissions. The fossil gasoline and diesel petroleum fuels used in internal combustion (IC) engines are one of the contributors to the global environmental degradation for their GHG emissions. Diesel engines contribute on important part of the worldDs transportation and industrial infrastructure, especially in heavy-duty equipment such as trucks, buses, construction and farm equipments, locomotives, ships etc. In the recent times, there are issues related to their GHG emissions such as, carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO). The use of alternative fuels is one of the most effective means of resolving this problem. Gaseous fuels receive more prominence in the domain of alternative fuels because of the possibilities of cleaner combustion. However, they are not suitable for compression ignition (CI) concept diesel engine when used alone due to their low cetane numbers and high auto-ignition temperatures. Hence, the CI engine of the Ddual fuelD approach plays a significant role in the efficient utilization of a wide range of gaseous fuels. During a dual fuel operation, a carbureted air-gas mixture is sucked and compressed like in a conventional diesel engine. The compressed air-gas mixture is fired by a small liquid fuel injection, pilot, which ignites spontaneously at the end of compression process. Biogas and syngas are the two alternative gaseous fuels examined in the present investigation. In general, Biogas is produced by Danaerobic digestionD process where the timing, pilot fuel mass inducted, intake manifold conditions, and type of gaseous fuel, have effects on the performance, combustion and emission characteristics of dual fuel diesel engines. However, the systematic investigations of individual parameters relevant to engine characterization have not been reported exhaustively in the literature. The second law analysis or evaluation of available energy determines the maximum possible performance of a thermodynamic system. In addition, impact of process change in the system in terms of system losses is also assessed. These findings help in reducing the availability loss to improve the performance of the engine in terms of efficiency and power output. However, there were only few literatures accessed on availability analysis of dual fuel engines. Therefore, the present contribution is focused to perform a systematic experimental investigation including the thermodynamic behavior of diesel engine under dual fuel mode. To accomplish the above problems of diesel engines, few additional components such as gas mixer and gas carburetor were designed, developed and incorporated into the base engine setup for executing the dual fuel operation. Experiments were conducted on a modified engine test unit so as to run biogas and syngas under dual fuel operations. The base diesel engine is a single-cylinder, constant-speed, water-cooled and direct-ignition diesel engine with a rated power of 5.2 kW at 1500 rpm.....