Cyclic variations on LPG and gasoline-fuelled lean burn SI engine

11 Pages·0.446 MB·English

by  Ceviz M.A., Yuksel F.

ARTICLE IN PRESS
RenewableEnergy](]]]])]]]–]]]
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Cyclic variations on LPG and gasoline-fuelled
lean burn SI engine
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M.A. Ceviz , F. Yu¨ ksel
DepartmentofMechanicalEngineering,FacultyofEngineering,UniversityofAtatu¨rk,Erzurum25240,Turkey
Received15January2005;accepted12September2005
Abstract
Leanoperationisanattractiveoperationalcondition;itisknownasoneofthemethodstoincrease
thermalefficiency,andtodecreaseexhaustemissionsandfuelconsumption.However,asthemixture
leans, cyclic variations increase. Cyclic variations are usually attributed to the result of random
fluctuations,excessairratioandflowfieldduetotheturbulentnatureoftheflowinthecylinderthat
limits the range of operating conditions of the spark ignition engine. Gaseous fuels as clean,
economical and abundant fuels can improve the lean operating limits and decrease the cyclic
variations.Therefore,thepurposeofthisresearchistoinvestigatetheuseofliquefiedpetroleumgas
(LPG) as a fuel for spark ignition engine in terms of lean operation, and focuses on the cyclic
variations and exhaust emissions. The results of this study showed that use of LPG decreased the
coefficient ofvariation in the indicatedmean effectivepressure,and emission.
r2005Elsevier Ltd. Allrights reserved.
Keywords:LPG;Cyclicvariations;S.I.engines;Exhaustemissions
1. Introduction
Cyclicvariationsininternalcombustionengineshavelongbeenrecognizedasalimiting
factor in engine performance, fuel efficiency, and emissions [1,2]. In particular, cyclic
variations are a major factor during lean operation. Lean operation is desired to reduce
nitrogen oxides and hydrocarbon emissions as well as to improve fuel efficiency. If cyclic
variations are large during engine operation near the lean combustion limit, combustion
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Correspondingauthor.Fax:[phone].
E-mailaddress:[email protected](M.A.Ceviz).
0022-5096/$-seefrontmatterr2005ElsevierLtd.Allrightsreserved.
doi:10.1016/j.renene.2005.09.016