Effect of Increasing Compression Ratio in a Light-Duty Natural Gas-Fueled Engine on Efficiency and Emissions

1993 ◽  
Author(s):  
Hannu E. Jääskeläinen ◽  
James S. Wallace
2002 ◽  
Author(s):  
Jan-Ola Olsson ◽  
Per Tunestål ◽  
Bengt Johansson ◽  
Scott Fiveland ◽  
Rey Agama ◽  
...  

Author(s):  
Jiří Vávra ◽  
Zbyněk Syrovátka ◽  
Michal Takáts ◽  
Eduardo Barrientos

This work presents an experimental investigation of advanced combustion of extremely lean natural gas / air mixture in a gas fueled automotive engine with a scavenged pre-chamber. The pre-chamber, which was designed and manufactured in-house, is scavenged with natural gas and is installed into a modified cylinder head of a gas fueled engine for a light duty truck. For initial pre-chamber ignition tests and optimizations, the engine is modified into a single cylinder one. The pre-chamber is equipped with a spark plug, fuel supply and a miniature pressure transducer. This arrangement allows a simultaneous crank angle resolved pressure measurement in the pre-chamber and in the main combustion chamber and provides important validation data for computational fluid dynamics (CFD) simulations. The results of the tests and initial optimizations show that the pre-chamber engine is able to operate within a significantly wider range of mixture composition than the conventional spark ignition engine. Full load operation of the pre-chamber engine is feasible with stoichiometric mixture (compatible with a three-way catalyst), without excessive thermal loading of components. At low load operation, the results show low NOx emissions with a high potential to fulfil current and future NOx limits without lean NOx exhaust gas after-treatment. The scavenged pre-chamber helps to increase the combustion rate mainly in the initial phase of combustion. However, significant unburned hydrocarbons emissions due to incomplete combustion need further optimizations. Thermal efficiency of lean operation of the engine with the pre-chamber compared to the conventional spark ignition system operated in stoichiometric conditions shows approximately 13% improvement.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4307
Author(s):  
Roberta De Robbio ◽  
Maria Cristina Cameretti ◽  
Ezio Mancaruso ◽  
Raffaele Tuccillo ◽  
Bianca Maria Vaglieco

Dual fuel engines induce benefits in terms of pollutant emissions of PM and NOx together with carbon dioxide reduction and being powered by natural gas (mainly methane) characterized by a low C/H ratio. Therefore, using natural gas (NG) in diesel engines can be a viable solution to reevaluate this type of engine and to prevent its disappearance from the automotive market, as it is a well-established technology in both energy and transportation fields. It is characterized by high performance and reliability. Nevertheless, further improvements are needed in terms of the optimization of combustion development, a more efficient oxidation, and a more efficient exploitation of gaseous fuel energy. To this aim, in this work, a CFD numerical methodology is described to simulate the processes that characterize combustion in a light-duty diesel engine in dual fuel mode by analyzing the effects of the changes in engine speed on the interaction between fluid-dynamics and chemistry as well as when the diesel/natural gas ratio changes at constant injected diesel amount. With the aid of experimental data obtained at the engine test bench on an optically accessible research engine, models of a 3D code, i.e., KIVA-3V, were validated. The ability to view images of OH distribution inside the cylinder allowed us to better model the complex combustion phenomenon of two fuels with very different burning characteristics. The numerical results also defined the importance of this free radical that characterizes the areas with the greatest combustion activity.


2004 ◽  
Author(s):  
Michael McMillian ◽  
Steven Richardson ◽  
Steven D. Woodruff ◽  
Dustin McIntyre

1992 ◽  
Author(s):  
Roy Meyer ◽  
David Meyers ◽  
Syed M. Shahed ◽  
Vinod K. Duggal
Keyword(s):  

1993 ◽  
Author(s):  
Chang Chang Hyun ◽  
Lee Hwang Bok ◽  
Myung Cha Lee ◽  
Yoon Kum Jung

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