Experimental Investigations of Intake and Exhaust Valve Timing Effects on Charge Dilution by Residuals, Fuel Consumption and Emissions at Part Load

Shayler, P. J.; Alger, Lawrence

doi:10.4271/2007-01-0478

Cited by 13 publications

(12 citation statements)

References 10 publications

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“…The sample flowrate represented typically around 1 per cent of the cylinder charge per cycle and provided sufficient power to feed directly to analysers. The sampling system is described in more detail in references [6] and [7]. Cylinder pressure measurements were made with a flush-mounted Kistler 6125A pressure transducer.…”

Section: Introductionmentioning

confidence: 99%

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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Section: Introductionmentioning

confidence: 99%

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 dependence of the burn rate on valve overlap is consistent with the fact that this has an important effect, and experiments were carried out to map the variation in dilution fraction by sampling the charge during the compression stroke, before spark ignition. The method used has been described in reference [4]. The sample is drawn from near the spark plug tip through a capillary tube.…”

Section: The Influence Of Valve Overlap Exerted Through Charge Dilutionmentioning

confidence: 99%

“…These include improved fuel economy due to reduced pumping work, and greater control over levels of internal recycling of combustion products to limit emissions formation [6,7]. The level of dilution is one of the factors which affect combustion characteristics [3,4,8,9]. The dilution is a strong function of the overlap period between intake valve opening (IVO) and exhaust valve closure (EVC), but not exclusively, and valve timings may also influence combustion characteristics through effects on charge motion and turbulence [5,10].…”

Section: Introductionmentioning

confidence: 99%

Factors influencing the burn rate characteristics of a spark ignition engine with variable valve timing

Bonatesta

Shayler

2008

Proceedings of the Institution of Mechanical Engineers, Part D:

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The charge burn characteristics of a four-cylinder port-fuel-injected spark ignition engine fitted with a dual independent variable-valve-timing system have been investigated experimentally. The influence of valve timings on the flame development angle and the rapid burn angle is primarily associated with valve overlap values and internal gas recirculation. Conditions examined cover light to medium loads and engine speeds up to 3500 r/min. As engine loads and speeds exceeded about 6 bar net indicated mean effective pressure and 3000 r/min respectively, combustion duration was virtually independent of the valve timing setting. At lower speeds and work output conditions, valve timing influenced burn angles through changes in dilution mass fraction, charge density, and charge temperature. Of these, changes in dilution mass fraction had the greatest influence. Increasing the dilution by increasing the valve overlap produced an increase in both burn angles. The effects of mean piston speed and spark timing have also been examined, and empirical expressions for the flame development and the rapid burn angles are presented.

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“…Since this burned gas causes the leaner mixture in the combustion chamber, it leads to decrease in the maximum temperature of a combustion chamber. NOx has a direct relationship with the maximum temperature of a combustion chamber and it can be adjusted by exact adjusting the valve timing (Shayler, 2007).…”

Section: Volumetric Efficiencymentioning

confidence: 99%

“…The improvements can be achieved with the lowest change in the engine and hence less cost. Shayler (2007) investigated the effect of valve timing on the amount of burned gas that remains from pervious cycle in the combustion chamber. He concluded that valve timing has a noticeable effect on the entrance of a fresh mixture.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation on the effect of different parameters on the performance and the emission of a spark ignition (SI) engine

Mirgolbabaei¹,

Bozorgi²,

Etghani³

2013

Int. J. Phys. Sci.

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In this work, NISSAN Z24 engine was simulated numerically and valves and ignition timings were modified in order to improve the engine performance and emissions. The engine was simulated using a version of the Los Alamos code KIVA-3V2 which is a computer program for the numerical calculation of transient, two and three dimensional chemically reactive flows with sprays. The computational grid was generated by the commercial software, ANSYS ICEM CFD. To validate the code, a comparison between experimental and theoretical results has been made, which confirm good qualitative agreement between these results. A series of parametric studied is performed to gain a better understanding of the effects of valves and ignition timings on the engine performance and emission. The results show that the engine volumetric efficiency, output power, emissions and performance are well improved by applying the optimal values.

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Experimental Investigations of Intake and Exhaust Valve Timing Effects on Charge Dilution by Residuals, Fuel Consumption and Emissions at Part Load

Cited by 13 publications

References 10 publications

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

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

Factors influencing the burn rate characteristics of a spark ignition engine with variable valve timing

Numerical investigation on the effect of different parameters on the performance and the emission of a spark ignition (SI) engine

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