Life of Fuel in Engine Cylinder

Oppenheim, A. K.; Kuhl, A. L.

doi:10.4271/980780

Cited by 15 publications

(3 citation statements)

References 16 publications

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“…Oppenheim and his associates developed a special function (life function) based on the Wiebe formulation, which was used to model fuel consumption in an internal combustion engine [82] and combustion of trinitrotoluene (TNT) products in a confined explosion [83,84]. In the latter application, the detonation products (C, CO) act as hot fuel, which is oxidized by air, forming combustion products.…”

Section: Single-wiebe Function Applicationsmentioning

confidence: 99%

Review of the development and applications of the Wiebe function: A tribute to the contribution of Ivan Wiebe to engine research

Ghojel

2010

International Journal of Engine Research

243

120

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Analytical functions approximating the burn rate in internal combustion engines are useful and cost-effective tools for engine cycle simulations. Most functions proposed to date are based on the law of normal distribution of a continuous random variable. The best known of these is the Wiebe function, which is used to predict the burn fraction and burn rate in internal combustion engines operating with different combustion systems and fuels. These include direct injection (DI) and indirect injection (IDI) diesel engines, classical spark ignition (SI) engines and gasoline direct injection (GDI) engines, engines with homogeneous charge compression ignition (HCCI) and premixed charge compression ignition (PCCI). This paper is a tribute to the lasting legacy of the Wiebe function and to the man behind it, Ivan Ivanovitch Wiebe. It includes a historical background to the development of the function in the mid 1950s in the Soviet Union, the controversy that surrounded its introduction, a description of the method used to arrive at the final formulation, and an overview of the many applications as prescriptive or predictive single-, double- and multi-function combustion models in engine research.

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Section: Single-wiebe Function Applicationsmentioning

confidence: 99%

Review of the development and applications of the Wiebe function: A tribute to the contribution of Ivan Wiebe to engine research

Ghojel

2010

International Journal of Engine Research

243

120

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“…There are numerous examples of the Wiebe function being used to describe the burn rate variation of spark ignition engines running on gasoline [1][2][3] or natural gas [4,5]. In the current study, accounting for the influence of changes in the charge dilution by burned gas has been of particular interest because of the potentially large variations produced by changes in valve timing and the high rates of external exhaust gas recirculation now commonly used on spark ignition engines.…”

Section: Introductionmentioning

confidence: 98%

Burn angles and form factors for Wiebe function fits to mass fraction burned curves of a spark ignition engine with variable valve timing

Bonatesta

Waters

Shayler

2009

International Journal of Engine Research

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The charge burn characteristics of a port-injected spark ignition engine with a pentroof combustion chamber and variable valve timing have been investigated experimentally. The engine was run under stoichiometric mixture operating conditions over ranges of intake and exhaust valve timings, engine speed, and engine load. Empirical functions have been developed for the 0-90 per cent mass fraction burned angle and the form factor, which define Wiebe function fits to the mass fraction burned variation in the crank angle domain. The burn angle and form factor have been related to the level of charge dilution by burned gas, engine speed, ignition timing, and charge density at spark timing. The dilution level has the strongest influence on the burn rate and profile. The dilution level varied with intake and exhaust valve timings, external exhaust gas recirculation, and engine load. The results indicate that intake and exhaust valve timings influence combustion primarily by modifying the charge dilution with burned gas and charge density.

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“…The result, which is typically based on a law of normal distribution representing the engine burning rate, is a very flexible function, heavily used in the last few decades to model all forms and modes of combustion, including compression and spark ignition, direct and indirect injection and homogeneous charge compression ignition combustion, with a range of liquid and gaseous fuels. An extensive survey on the implementation of the Wiebe function (as well as some mathematical modifications) has been also carried out by Oppenheim et al [49]. Here the authors recognise the practical virtues of the function and its well-established use, but question its derivation, which is described as a gigantic leap from chemical kinetics of the exothermic reactions of combustion to the consumption of fuel.…”

Section: Combustion Modelling Using the Wiebe Functionmentioning

confidence: 99%

Premixed Combustion in Spark Ignition Engines and the Influence of Operating Variables

Bonatesta¹

2013

Advances in Internal Combustion Engines and Fuel Technologies

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Advances in Internal Combustion Engines and Fuel Technologies 4 . . Overview of flame propagation mechanismDetailed observations of development and structure of the flame in SI engines can be made by using direct photographs or other methods such as Schlieren and shadowgraph photography techniques [ , ]. The initial stage of the combustion process is the development of a flame kernel, centred close to the spark-plug electrodes, that grows from the spark discharge with quasispherical, low-irregular surface its outer boundary corresponds to a thin sheet-like developing reaction front that separates burned and unburned gases. Engine combustion takes place in a turbulent environment produced by shear flows set up during the induction stroke and then modified during compression. Initially, the flame kernel is too small to incorporate most of the turbulence length scales available and, therefore, it is virtually not aware of the velocity fluctuations [ ]. Only the smallest scales of turbulence may influence the growing kernel, whereas bigger scales are presumed to only convect the flame-ball bodily the initial burning characteristics are similar to those found in a quiescent environment a laminar-like combustion development . As the kernel expands, it progressively experiences larger turbulent structures and the reaction front becomes increasingly wrinkled. During the main combustion stage, the thin reaction sheet becomes highly wrinkled and convoluted and the reaction zone, which separates burned and unburned gases, has been described as a thick turbulent flame brush. While the thickness of the initial sheet-like reaction front is of the order of . mm, the overall thickness of this turbulent flame brush can reach several millimetres this would depend on type of fuel, equivalence ratio and level of turbulence. The turbulent flow field, in particular velocity fluctuations, determines a conspicuous rate of entrainment in the reaction zone, which has been described [ , ] as being composed of many small pockets and isolated island of unburned gas within highly marked wrinkles that characterize a thin multi-connected reaction sheet. Theories have been advanced that describe the local boundary layer of this region as a quasi-spherical flame front, which diffuses outwards with laminar flame speed [ ].Gillespie and co-workers provide a useful review of those aspects of laminar and turbulent flame propagation, which are relevant to SI engines combustion [ ]. Similarly to laminar-like combustion taking place in a quiescent environment, two main definitions of time-based combustion rate can be proposed for turbulent combustion. The first one relates to the rate of formation of burned products velocity. The dependence of the combustion rate on turbulence is embodied in the velocity term, which is fundamentally modelled as a function of turbulence intensity, u ' , and laminar burning velocity, S L . The latter, loosely addressed to as laminar flame velocity in the context of simplified flame propagation models, has been demonstra...

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Life of Fuel in Engine Cylinder

Cited by 15 publications

References 16 publications

Review of the development and applications of the Wiebe function: A tribute to the contribution of Ivan Wiebe to engine research

Review of the development and applications of the Wiebe function: A tribute to the contribution of Ivan Wiebe to engine research

Burn angles and form factors for Wiebe function fits to mass fraction burned curves of a spark ignition engine with variable valve timing

Premixed Combustion in Spark Ignition Engines and the Influence of Operating Variables

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