The impact of ignition delay and further fuel properties on combustion and emissions in a compression ignition engine

2009 ◽

Author(s):

Gong Chen

Keyword(s):

Fuel Injection ◽

Cetane Number ◽

Fuel Properties ◽

Liquid Fuels ◽

Compression Ignition ◽

Heavy Duty ◽

Compression Ignition Engine ◽

End Effects ◽

Compression Ignition Engines ◽

The Impact

It is always desirable for a heavy-duty compression-ignition engine, such as a diesel engine, to possess a capability of using alternate liquid fuels without significant hardware modification to the engine baseline. Because fuel properties vary between various types of liquid fuels, it is important to understand the impact and effects of the fuel properties on engine operating and output parameters. This paper intends and attempts to achieve that understanding and to predict the qualitative effects by studying analytically and qualitatively how a heavy-duty compression-ignition engine would respond to the variation of fuel properties. The fuel properties considered in this paper mainly include the fuel density, compressibility, heating value, viscosity, cetane number, and distillation temperature range. The qualitative direct and end effects of the fuel properties on engine bulk fuel injection, in-cylinder combustion, and outputs are analyzed and predicted. Understanding these effects can be useful in analyzing and designing a compression-ignition engine for using alternate liquid fuels.

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Ozone-Assisted Combustion—Part I: Literature Review and Kinetic Study Using Detailed n-Heptane Kinetic Mechanism

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4027068 ◽

2014 ◽

Vol 136 (9) ◽

Cited By ~ 7

Author(s):

Christopher Depcik ◽

Michael Mangus ◽

Colter Ragone

Keyword(s):

Ignition Delay ◽

Equivalence Ratio ◽

Atomic Oxygen ◽

Direct Injection ◽

Kinetic Mechanism ◽

Combustion Model ◽

Ozone Decomposition ◽

Compression Ignition ◽

Review Of The Literature ◽

Compression Ignition Engine

In this first paper, the authors undertake a review of the literature in the field of ozone-assisted combustion in order to summarize literature findings. The use of a detailed n-heptane combustion model including ozone kinetics helps analyze these earlier results and leads into experimentation within the authors' laboratory using a single-cylinder, direct-injection compression ignition engine, briefly discussed here and in more depth in a following paper. The literature and kinetic modeling outcomes indicate that the addition of ozone leads to a decrease in ignition delay, both in comparison to no added ozone and with a decreasing equivalence ratio. This ignition delay decrease as the mixture leans is counter to the traditional increase in ignition delay with decreasing equivalence ratio. Moreover, the inclusion of ozone results in slightly higher temperatures in the cylinder due to ozone decomposition, augmented production of nitrogen oxides, and reduction in particulate matter through radial atomic oxygen chemistry. Of additional importance, acetylene levels decrease but carbon monoxide emissions are found to both increase and decrease as a function of equivalence ratio. This work illustrates that, beyond a certain level of assistance (approximately 20 ppm for the compression ratio of the authors' engine), adding more ozone has a negligible influence on combustion and emissions. This occurs because the introduction of O3 into the intake causes a temperature-limited equilibrium set of reactions via the atomic oxygen radical produced.

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