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

Abstract

The charge burn characteristics of a port-injected spark ignition engine with a pent-roof 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.

Keywords

spark ignition engine Wiebe function combustion duration burn angle form factor

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References

Oppenheim

Kuhl

, ‘Life of fuel in a cylinder.’ SAE paper 980780

Lindström

Angstrom

Kalghati

Moller

, ‘An empirical SI combustion model using laminar burning velocity correlations.’ SAE paper 2005-01-2106

Bayraktar

Durgun

, ‘Development of an empirical correlation for combustion durations in spark ignition engines.’ Energy Conversion and Mgmt 45 (2004): 1419–1431

Soylu

Van Gerpen

, ‘Development of empirically based burning rate sub-models for a natural gas engine.’ Energy Conversion and Mgmt 45 (2004): 467–481

Rousseau

Lemoult

Tazerout

, ‘Combustion characterization of natural gas in a lean burn spark-ignition engine.’ Proc. IMechE, Part D: J. Automobile Engineering 213 (D5) (1999): 481–489

Shayler

P. J.

Alger

, ‘A simple system for sampling cylinder gases and its application to measure dilution by residuals on a S.I. engine with VVT.’ JSAE paper 20065409

Shayler

P. J.

Alger

, ‘Experimental investigations of intake and exhaust valve timing effects on charge dilution by residuals, fuel consumption and emissions at part load.’ SAE paper 2007-01-0478

Rassweiler

Withrow

, ‘Motion pictures of engine flames correlated with pressure cards.’ SAE paper 800131

Bonatesta

, ‘The charge burn characteristics of a gasoline engine and the influence of valve timing.’ PhD Dissertation, University of Nottingham

10.

Shayler

P. J.

Wiseman

, ‘Improving the determination of mass fraction burnt.’ SAE paper 900351

11.

Scharrer

Heinrich

Gebhard

Pucher

, ‘Predictive engine part load modelling for the development of a double variable cam phasing (DVCP) strategy.’ SAE paper 2004-01-0614

12.

Csallner

, ‘Eine Methode zur Vorausberechnung des Brennverlaufs von Ottomotoren bei geänderten Betriebsbedingungen.’ Dissertation TU München

13.

Witt

, ‘Analyse der thermodynamischen Verluste eines Ottomotors unter den Randbedingungen Variber Steuerzeiten.’ Dissertation, Graz Technical University

14.

Hires

Tabaczynski

Novak

, ‘The prediction of ignition delay and combustion intervals for a homogeneous charge spark ignition engine.’ SAE paper 780232

15.

Vávra

Takáts

, ‘Heat release regression model for gas fuelled SI engines.’ SAE paper 2004-01-1462

16.

Heywood

J. B.

, Internal combustion engine fundamentals, Automotive Technology Series (: McGraw-Hill Book Company 1988)

17.

Chen

Veshagh

, ‘A refinement of flame propogation model for spark-ignition engines.’ SAE paper 920679

18.

Rhodes

Keck

, ‘Laminar burning speed measurements of indolene—air-diluent mixtures at high pressures and temperatures.’ SAE paper 850047

19.

Metghalchi

Keck

, ‘Burning velocities of air with methanol, isooctane and indolene at high pressure and temperature.’ Combustion and Flame 48 (1982): 191–210

20.

Bonatesta

Shayler

P. J.

, ‘Factors influencing the burn rate characteristics of a spark ignition engine with variable valve timing.’ Proc. IMechE, Part D: J. Automobile Engineering 222 (D11) (2008): 2147–2158 DOI: 10.1243/09544070JAUTO873