Analysis of Combustion in Diesel Engines Fueled by Directly Injected Natural Gas

Abstract

A single-cylinder two-stroke (DDC 1-71) diesel engine has been fueled with natural gas directly injected at high pressure into the engine cylinder. Prior to injection of the natural gas, a quantity of diesel fuel is injected into the cylinder (from the same injector) to provide for gas ignition. Tests have been conducted at medium load and speed over a wide range of injection timing, and with both conventional diesel and gas/diesel operation. With natural gas fueling, significant reduction in nitrogen oxide emissions have been measured without significant loss in efficiency, relative to conventional diesel operation. Using measurements of cylinder pressure development, a new method of combustion analysis has been used to estimate mass burning rate, burned gas temperature, and rate of nitrogen oxide (NO) generation. The method uses a nonlinear regression technique to determine the distribution with crank angle of the cylinder heat loss rate. The method assumes that NO formation takes place within one turbulent mixing time following combustion of each fuel-air increment. Comparison of measured and calculated NO concentration in the exhaust over the whole range of injection timing shows that for both conventional diesel and gas/diesel operation the effective turbulent mixing period is equivalent to 4 degrees of crank angle at 1250 RPM. The results demonstrate that a mass burned method can be used to infer cylinder temperature distributions and NO formation rate as well as the progress of combustion. [S0742-4795(00)02101-3]

Experimental Test of a New Compressed Natural Gas Engine with Direct Injection

“…Research investigation on in-cylinder direct injection (with Otto cycle) CNG-DI engine is not found in literature. However, many researchers have conducted works on CNG-DI system for diesel engine as in Ref [1][2][3][4][5][6]. Hence, the output of this investigation and developing capabilities for advanced CNG-DI engine using gasoline cycle with SI system will be one of the realization of engineering dreams.…”

Green Engines Development Using Compressed Natural Gas as an Alternative Fuel: A Review

“…Any researcher [42][43][44][45][46] was researched about the compressed natural gas as alternative fuel motivated by the economic, emissions and strategic advantages of alternative fuels. Several alternative fuels have been recognized as having a significant potential for producing lower overall pollutant emissions compared to gasoline and diesel fuel.…”

“…A 15-20% loss in thermal efficiency was reported in a dual-fuel heavy-duty truck demonstration in Canada, where natural gas provided 60% of the total fuel requirement during dual-fuel operation [5] . A further disadvantage of methane is that it is a greenhouse gas with a warming forcing factor many times that of the principal greenhouse gas, CO 2 , Gas leakage or vehicular emission, therefore and the size of release, will have an impact on the overall greenhouse gas (GHG) emissions performance relative to the petrol or diesel fuel it substitutes [42][43][44][45][46] . The safety aspects of converting vehicles to run on CNG are of concern to many people.…”

Experimental investigation on performance and heat release analysis of a pilot ignited direct injection natural gas engine

“…It can be summarized from his study that the combustion rate of dual fuel mode was higher than that of pure diesel mode and the combustion rates of both modes decreased with increasing load as a result of the increased proportion of mixing-controlled combustion. Hill and Douville [8] proposed a method incorporating nonlinear regression technique to determine the cylinder heat loss rate, the ignition delay, the mass burning rate as well as the burned gas temperature by measurements of intake/exhaust charge and in-cylinder pressure curves. Li et al [9] presented a CFD (computational fluid dynamics) combustion model together with an injector model to simulate the in-cylinder mixing and combustion process.…”