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

Bonatesta, Fabrizio; Waters, Bryony; Shayler, P. J.

doi:10.1243/14680874jer05009

Cited by 37 publications

(33 citation statements)

References 13 publications

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“…Charge density function is consistent with reported results [10], where lower combustion angles are attained when increasing charge density at spark timing. A wide range of charge density values are achieved during engine testing which provides good samples for the database population.…”

Section: ( )supporting

confidence: 91%

“…Direct application of previously published functions provides Fig.1, where comparisons of burn angles and form factors are presented. Results show that both, burn angle and form factor, obtained with existing functions [10] do not correlate with enough accuracy with data obtained in this work. Therefore, it is necessary to develop new functions for small two-stroke engines, whose characteristics differ greatly from conventional four-stroke automotive engines mainly due to differences in engine speed and in-cylinder conditions during the combustion process.…”

contrasting

confidence: 63%

“…The Wiebe function [10,14] is a very convenient method to simulate fuel burning in internal combustion spark-ignition engines. The Wiebe function for the mass fraction burned is given by:…”

Section: Combustion Diagnostic Model Descriptionmentioning

confidence: 99%

“…Besides the HRR determination issue, which can be coped with empirical assistance and convenient use of theoretical models, Wiebe function parameters selection for simulations at different engine running conditions still remains unclear. Literature survey did not help on finding out ready-to-use correlations for these parameters in the frame of small two-stroke engines.Empirical functions [9,10] were developed for the 0-90 per cent mass fraction burned angle and the factor form for a 1600cc four-stroke spark-ignition engine. Direct application of previously published functions provides Fig.1, where comparisons of burn angles and form factors are presented.…”

mentioning

confidence: 99%

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Correlations for Wiebe function parameters for combustion simulation in two-stroke small engines

Galindo

Climent

Plá

et al. 2011

Applied Thermal Engineering

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Combustion simulation in two-stroke engines becomes necessary not only for engine performance prediction but also for scavenge evaluation, since in-cylinder pressure and temperature are highly influenced by combustion process evolution. Combustion simulation by using a Wiebe function is appropriate to be included in a 1D engine code for providing design criteria with fast and accurate calculations; the main drawback is the determination of the four Wiebe parameters needed to build up the in-cylinder heat release. This paper deals with a detailed methodology for heat release determination in two-stroke engines under wide range of running conditions; obtained empirical data will serve for building ad-hoc Wiebe functions, whose four parameters will be finally correlated with engine related parameters derived from 1D simulations. Two different engines, with three exhaust systems each, varying engine speed and spark ignition timing were used to obtain correlations far from particular situations. A multiple regression analysis stated that charge density, residual gas fraction, spark timing and mean piston speed were the significant engine parameters that influence on Wiebe parameters. Finally, two scenarios were considered regarding Wiebe parameters: a) specific correlations different for each engine gave coefficient of multiple determination values higher than 98% when predicting indicated mean effective pressure, b) a global correlation used for both engines provided R 2 values of 93% in the 50 cc and 91% in the 125 cc engine. 1. INTRODUCCION Small two-stroke engines, which are widely used in mobile machinery, will have to accomplish strict anti-pollution standards in imminent years. Active and passive solutions applied to two-2 stroke engines design have arisen in the last decades. Conforming active solutions, exhaust emissions reduction technologies have been investigated [1-3], and on the other hand, within passive solutions, current engine systems with different technologies (carburettor, direct injection, catalyst) are being improved and evaluated in terms of emission control [4]. The use of computer simulations to aid engine systems design process has been largely applied and has become a popular tool because of combination of accurate results and reduced costs. Combustion simulation in two-stroke engines becomes necessary not only for engine performance prediction but also for scavenge evaluation, since in-cylinder pressure and temperature are highly influenced by combustion process evolution. The cylinder blow-down, which is originated when the exhaust port opens and configures the exhaust port instantaneous pressure due to wave propagation phenomena inside the exhaust system, depends highly on in-cylinder conditions at exhaust port opening. Several approaches may be considered for combustion modelling. Enumerating in time consuming order one may find: computational fluid dynamics codes and quasi-dimensional combustion models on one side, and combustion empirical models on the other side. The former techniqu...

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Section: ( )supporting

confidence: 91%

contrasting

confidence: 63%

“…The Wiebe function [10,14] is a very convenient method to simulate fuel burning in internal combustion spark-ignition engines. The Wiebe function for the mass fraction burned is given by:…”

Section: Combustion Diagnostic Model Descriptionmentioning

confidence: 99%

mentioning

confidence: 99%

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Correlations for Wiebe function parameters for combustion simulation in two-stroke small engines

Galindo

Climent

Plá

et al. 2011

Applied Thermal Engineering

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“…Similarly, Szwaja et al [22] found that combustion knock phenomenon are due to greater peak of the mass fraction burn. Bonatesta et al [23] had develop an empirical function for the 0 to 90 per cent mass fraction burned to define according to Wiebe function.…”

mentioning

confidence: 99%

Experimental investigation of butanol gasoline blends effect on the mass fraction burned in a spark ignition engine

Yusri¹,

Osman²,

Mamat³

et al. 2016

IJET

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Abstract-The growing energy demand and the limitation of the fossil fuels force the transportation sector to seek for alternative energy sources. Butanol has emerged as one of the potential alternative energy solution especially for spark ignition engines. Experimental study on engine combustion characteristics particularly on mass fraction burned (MFB) of spark ignition engines fueled with secondary butyl alcohol (sec-butanol) gasoline blends was carried out. Engine was operated at engine speeds 3500 RPM with 50% of wide throttle open (WTO) for each blend (5%, 10% and 15% volume of sec-butanol) and neat gasoline. The in-cylinder pressure data were collected and the average cycle was integrate to obtain MFB profiles. Based on the MFB results at using sec-butanol gasoline blends is always taken higher value of degree of crank angle compared to gasoline fuels. However, throughout the analysis, by addition of 15% of volume in gasoline fuels reduced the 10 -90% early flame propagation, 10 -90% combustion duration and early position of degree of crank angle at 50% of MFB for 1.7%, 4.5% and 5.9% respectively with respect ot gasoline fuels.Index Terms-sec-butanol, gasoline fuels (G100), mass fraction burned (MFB) I. INTRODUCTION nergy security is an increasing critical issues due to the potential of fossil fuels dearth in near future [1]. As in consequences, the global energy consumption brings adverse effect toward environment and human health [2]. In 2013, the most consumed energy came from non-renewable energy which accounted for 82.67% among other energy sources in which crude oil, coal and natural gas by 30.92%, 28.95% and 22.81% respectively [3]. The petroleum fuels play a key factor especially in transportation area to meet the basic necessity of human needs. In order to combat the scarcity of petroleum fuels particularly in transportation areas a more efforts need to be done to find clean and sustainable alternative fuel [4].Gasoline engines are mostly the best choices for private and commercial used [5]. The use of oxygenated fuels in gasoline engines has a great potential of reducing the dependency of the petroleum fuels [6]. The main oxygenated alternative fuel used is alcohols mainly from ethanol for operation of gasoline-type vehicles [7]. However, for the past few years, the investigation of ethanol has received considerable critical attention with less attention paid to the butanol as a sustainable alternative fuel.Butanol is consider as an advanced alternative biofuel [8,9]. Butanol is a four carbon atom alcohol with chemical formula of C 4 H 10 O [10]. There are four types of butanol isomers categorized as n-butanol, secbutanol, tert-butanol and iso-butanol [11,12]. Each butanol is recognized based on their hydroxyl attached to one of the carbon atoms [13]. Each of these isomers have different physical and chemical properties [14]. As compared to ethanol, butanol is the most similar fuel properties to the gasoline fuel such as lower heating value, stoichiometric air-fuel ratio, research octane number a...

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Thermodynamic Modelling of Combustion Process in a Spark Ignition Engine and its Numerical Prediction

Shree

Ganesan

2017

Combustion for Power Generation and Transportation

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

Cited by 37 publications

References 13 publications

Correlations for Wiebe function parameters for combustion simulation in two-stroke small engines

Correlations for Wiebe function parameters for combustion simulation in two-stroke small engines

Experimental investigation of butanol gasoline blends effect on the mass fraction burned in a spark ignition engine

Thermodynamic Modelling of Combustion Process in a Spark Ignition Engine and its Numerical Prediction

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