engleski

The Literature Review on Dual Fuel Diesel-Natural Gas Combustion, Emission and Performance

As a result of the latest trends in the automotive industry that have put stringent requirements on the fuel consumption and exhaust gas emission, the engine research has been directed towards optimization of the combustion process and application of the variety of cleaner fuels. In that context the use of natural gas as a partial supplement for the liquid Diesel fuel has attracted a lot of attention. This paper presents the literature review of recent research on dual fuel Diesel-natural gas operation. It presents the benefits and drawbacks of dual fuel Diesel-natural gas operation as well as the means and methods to circumvent these drawbacks. The use of natural gas as a partial supplement for Diesel liquid fuel has been suggested due to its cleaner nature of combustion, its worldwide availability and its potential to reduce both global (CO2) and local (NOx, soot) exhaust gas emissions from conventional Diesel engines. As natural gas is consisted primarily of methane (CH4), it has high H/C ratio thus having the theoretical potential to reduce the CO2 emission by nearly 25% compared to conventional Diesel fuel. What makes dual fuel operation possible is the flammability limit between the two fuels and it exploits the advantages of each one. Diesel fuel pilot is used as a high energy ignition device (Diesel fuel pilot releases 10000 times more energy compared to the energy delivered by spark the in spark-ignition engine) while natural gas is used as a primary fuel in the operation. Several dual fuel combustion strategies have been proposed ; (a) conventional dual fuel combustion that operates with premixed natural gas which is ignited by the Diesel fuel pilot ; (b) direct injected dual fuel combustion, where both natural gas and Diesel pilot fuel are directly injected into the cylinder at the end of the compression stroke ; (c) HCCI like combustion (PCCI, RCCI) where combustion is primarily controlled by the natural gas/Diesel fuel ratio. Although dual fuel combustion has shown significant potential it still faces some challenges, among which HC and CO emission at low load and preignition and knock at high load are the major ones.

Dual-Fuel Diesel–Natural Gas Operation; Combustion; Emission; Performance

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