ever,amassproductioncamlessenginehasnotyetbeenproduced.nthisstudyanEMVsystemwasdesignedbasedonsystemsbuiltbyotherengineers.TheEMVengine(asemielectro-mechanicalcamlessengine),whichenableselectro-mechanicaloperationoftheintakevalve,andastandardengineweretestedtounderstandtheeffectofEMVsonengineperformanceandemissionsatdifferentenginespeedsunderload.Duringtheenginetestsenginevalvetiming,valveopeningdofvalveopening.ThepowerandtorqueincreaseobtainedbyusingvariableintakevalvetimingisbetweenandTheimprovementinfuelconsumptionobtainedbyvariableintakevalvetimingisbetweenand(AhmadandTheobald,;BarkanandDresner,;DresnerandBarkan,;Asmus,;Demmelbaueretal.,;Gouldetal.,;Hatanoetal.,;Urataetal.,;Leeetal.,;LevinandSchlecter,;Moriyaetal.,;Pischingeretal.,).TheimprovementinCOemissionsobtainedusingvariableintakevalvetimingisbetweenand(DresnerandBarkan,;Gouldetal.,;Leeetal.,;Moriyaetal.,).Insomestudies,hydrocarbon(HC)emissionswereshowntoincreasewiththeuseofvariablevalvetiming(e.g.,Leeetal.,).OtherstudiesshowedthatHCemissionswerereducedbybetweenand(DresnerandBarkan,;Gouldetal.,;Lancefieldetal.,;Moriyaetal.,).Noxemissionswerereportedtodecreasebyfromto(DresnerandBarkan,;Gouldetal.,;Leeetal.,;Moriyaetal.,).Theopeningspeedofthevalveincreasesthevolumetricefficiencyoftheengineandthereductioninvalveliftingdecreasesthefrictionarisinginthevalves(LevinandSchlecter,).WithavariablevalvetimingsystememployingtheEMVsystem,allrelevantparameterscanbecontrolledsimultaneouslyandcompletelyindependently.Therefore,inadditiontoimprovementsinfueleconomyandemissions,engineperformanceisgreatlyimproved(LevinandSchlecter,;Pischingeretal.,).Thevariablevalvetimingsystem,whichisacompletelyelectro-mechanicalsystem,doesnotneedacamshaftandthereforeenablestheproductionofacamlessengine.Asemielectro-mechanicalcamlessengineisoneinwhichonlyintakeoronlyexhaustvalvesaredrivenelectro-mechanically.Camlessenginesystemshaveagreatpotentialastheyhavetheadvantagesofamechanicallyworkingvariablevalvetimingsystemandbecausethecontrolofvalveperformanceparametersiseasier.Thereisaconsiderablecollectionofliteratureoncamlessengines.RecentstudieshavefocussedonthecontrolofthesolenoidsusedintheEMVsystemandcomputermodelingofsuchcontrolsystems(Stubbs,;Boie,;Wang,;Changetal.,;Tai,;Wangetal.,;HoffmannandStefanopoulou,;Nituetal.,;PetersonandStefanopoulou,;KamisandYuksel,;Copeetal.,).However,amassproductioncamlessenginehasnotyetbeenproduced.nthisstudyanEMVsystemwasdesignedbasedonsystemsbuiltbyotherengineers.TheEMVengine(asemielectro-mechanicalcamlessengine),whichenableselectro-mechanicaloperationoftheintakevalve,andastandardengineweretestedtounderstandtheeffectofEMVsonengineperformanceandemissionsatdifferentenginespeedsunderload.Duringtheenginetestsenginevalvetiming,valveopeningd控制下完成。(表一)测试实验是由包含实验设置(图)测功机、油耗仪、尾气分析系统、EMV系统及EMV系统测试仪器组成。在表中给出了在实验中使用技术参数。首先是在不同转速部分负荷下发动机运行情况。然后在同一台发动机上在装上EMV系统后,比较在同一运行参数下运行情况。主要测试EMV系统及相关零件,测试结果在示波器上显示。发动机和EMV性能在试验中同时获得。排放性能使用德国产L尾气分析仪。在表中给出尾气分析仪相关参数。采集数据有发动机扭矩、发动机功率、燃油消耗、过量空气系数(λ)、CO、HC和氮氧化物排放量。此外,在电流通过时候,记录次级线圈和传感器信号流。五.结果与讨论发动机性能图显示了EMV发动机和参照发动机扭矩对比,相对于参照发动机EMV发动机在r/min时扭矩增长.,在至r/min中扭矩平均增长,而在高转速r/min时扭矩增长.。气门开启和关闭速度取决于控制系统算法。并且气门开启和关闭算法是放在EMV系统文件中。进气门完全开放时间长因为进气门打开速度更快。此外,气门横断面差异对发动机性能和排放也有很大影响。(Ergeneman、)。在特定气门截面下,EMV发动机比参照发动机时间截面参数高.(图)。增加气门时间截面参数原因有很多。例如在活塞下行开始进气时产生一个更强气流。EMV系统能使进气门很快开启以至于发动机能有一个气门重叠区域。气门重叠是指四冲程发动机活塞在上止点处,进排气门都处于开启状态。如图所示,在这项研究中EMV发动机比参照发动机气门重叠面积多。减小发动机进气负功就要增加气门重叠面积。同样,气门重叠角增加意味着进气歧管压力增加(哈马隆德仙芬黛年;勒罗伊等,年)。在参照发动机上气门重叠面积增加相当于延长气门重叠期(Ergeneman等,年)。在低速情况下,气门重叠期影响发动机排放性能在燃烧室中已经开始了。这就是所谓内部产生废气再循环还是内部废气再循环。延长气门重叠期有利于内部废气再循环。但是在低速下延长气门重叠期将导致发动机性能降低(ınar,年;Akbaş,年)。当参照发动机转速接近r/min时,过量空气系数λ<(图)。原因是在EMV发动机中在高速下进气门开启得更加迅速有更多空气进入气缸。由于在两个发动机中使用燃料质量是相同,所以在EMV发动机中混合气将变稀。在装有EMV系统发动机上,在低速或者是高速下扭矩增加量会降低,这是因为在新进空气燃料混合气中混有从排气中引进废气。在参照发动机上新鲜空气燃料混合气会随着废气一起排到气缸外。然而,扭矩增加会降到最低,因为消耗在气门摩擦上无用功减少。在装有EMV系统发动机和参照发动机功率变化如图所示,相对于参照发动机在EMV发动机上功率和扭矩都有增加。增加气门开启速度以及增加气门开启截面积都会使发动机容积效率增加(图)。气门重叠在低速下会影响发动机功率,并且随着重叠期延长影响更加明显。在高速下,EMV系统电源是由运行发动机提供且在参照发动机上这一数量是相当。这是有因为发动机以最高速度运转时,空气燃料混合气将变得稀薄。然而,EMV发动机功率会有一个较小增加,因为在EMV发动机机械运动件较少。所以,气门摩擦有利于提高发动机性能。图显示了EMV发动机和参照发动机平均油耗变化。相对于参照发动机在EMV发动机上在转速为r/min时平均油耗会降低.,在转速从到r/min中平均油耗会平均降低.而在r/min时平均油耗会降低.。由于在EMV发动机比参照发动机摩擦损失少所以扭矩增加较多。此外由于气门截面时间变化,在EMV发动机上平均油耗得到改善。由于机械零件减少导致机械效率提高特别是在高速情况下更能改善发动机性能和油耗。六.结论这项研究是根据已发布研究基础,对单缸发动机进气门机电控制系统设计和制造。EMV系统测试是在满负荷和在宽广发动机转速条件下完成,结合我们实验结果,我们认为:与参照发动机相比,EMV系统发动机具有较高潜力提高发动机扭矩,降低BSFC,在实验中反映在过量空气系数增加,整体可以获得CO排放降低,HC排放降低,氮氧化物排放降低。用于EMV系统研究电源是伏直流电,此工作电压比伏EMV系统低。此外,发动机最高转速提高。此外,根据发动机负荷,不更改电气组件组成EMV系统行为。同时,执行器响应速度和使用发动机进气门转速同步。包括了制动器电磁线圈优化设计可减少EMV系统电力需求。EMV系统可更有效地使用更强致动器、传感器和微控制器。如果在内燃机中使用EMV系统,则可以消除一些机械部分(凸轮轴、摇臂武等)。在与完全控制气门性能参数及在空气燃料混合料优化系统EMV,可以进一步提高发动机性能与排放方面改进。在今后研究中,发动机对凸轮轴没有依赖,将完全淘汰驱动排气门以及进气门机械。ofvalveopening.ThepowerandtorqueincreaseobtainedbyusingvariableintakevalvetimingisbetweenandTheimprovementinfuelconsumptionobtainedbyvariableintakevalvetimingisbetweenand(AhmadandTheobald,;BarkanandDresner,;DresnerandBarkan,;Asmus,;Demmelbaueretal.,;Gouldetal.,;Hatanoetal.,;Urataetal.,;Leeetal.,;LevinandSchlecter,;Moriyaetal.,;Pischingeretal.,).TheimprovementinCOemissionsobtainedusingvariableintakEffectofasemielectro-mechanicalenginevalveonperformanceandemissionsinasinglecylindersparkignitedengine(DepartmentofAutomotiveEducation,KarabukUniversity,Karabuk,Turkey)E-mail:ozdalyan@hotmail.com;dogan_oguzhan@yahoo.co.ukReceivedFeb.,;RevisionacceptedJuly,;CrosscheckedNov.,Abstract:Inthisstudy,anelectro-mechanicalvalve(EMV)systemfortheintakevalveofafourstroke,singlecylinder,overheadvalveandsparkignition(SI)enginewasdesignedandconstructed.AnenginewiththeEMVsystemandastandardengineweretestedtoobservetheeffectsoftheEMVonengineperformanceandemissionsatdifferentspeedsunderfullload.TheEMVengineshowedimprovedenginepower,enginetorqueandbreakspecificfuelconsumption(BSFC).AdecreaseinCOemissionswasalsoobtainedwiththeEMVsystem,buthydrocarbons(HC)andNOxemissionsincreasedbyandrespectively.Keywords:Semielectro-mechanic,Camlessengine,Electro-mechanicenginevalve,Engineperformance,Emissionsdoi:./jzus.ADocumentcode:ACLCnumber:TH.IntroductionAllinternalcombustionengines(ICE)havemechanicallyactuatedsystemsforopeningintakeandexhaustvalves.Traditionalvalvesystemshavecon-stantvalvetimingwhichrestrictsengineperformanceespeciallyatlowandathighenginespeeds.Control-lingvalveoperationinICE’seffectivemethodforimprovingengineperformanceandemissionsoverarangeofenginespeeds.Parameterssuchascamshape,valvetiming,valveopeningdurationandvalveliftinghaveamajorimpactonengineperformanceandemissions(BarkanandDresner,;Krauteretal.,;Hatanoetal.,;Cinar,;Akba,;Pischingeretal.,;Steinetal.,).Toincreasetorqueandreducefuelconsumptioningasolineengines,manufacturersareincreasinglyusingvariablevalvetimingsystemsinproductionengines.Mostvalvetimingsystemsusedforimprovingengineperformancearedependentonthecamshaft.Themechanicalvariablevalvetimingsystemsarecomplexbutgreatlyreducethelimitationsoftraditionalvalvesystems,especiallyinregardtovolumetricefficiency(BarkanandDresner,).However,exceptforBMW’sValvetronicsystem,theycannotcontrolallparameterssuchasvalvetiming,valveliftingandvalveopeningdurationsimultane-ously,continuouslyandcompletelyindependently.LotusEngineeringhasdevelopedresearchandproductionversionsoftheirfullyvariablevalvesystemthatarenotdependentoncamshafts.TheLotussystemcanalsoindependentlycontrolvalvetiming,valveliftingandthedurationofvalveopening.ThepowerandtorqueincreaseobtainedbyusingvariableintakevalvetimingisbetweenandTheimprovementinfuelconsumptionobtainedbyvariableintakevalvetimingisbetweenand(AhmadandTheobald,;BarkanandDresner,;DresnerandBarkan,;Asmus,;Demmelbaueretal.,;Gouldetal.,;Hatanoetal.,;Urataetal.,;Leeetal.,;LevinandSchlecter,;Moriyaetal.,;Pischingeretal.,).TheimprovementinCOemissionsobtainedusingvariableintakevalvetimingisbetweenand(DresnerandBarkan,;Gouldetal.,;Leeetal.,;Moriyaetal.,).Insomestudies,hydrocarbon(HC)emissionswereshowntoincreasewiththeuseofvariablevalvetiming(e.g.,Leeetal.,).OtherstudiesshowedthatHCemissionswerereducedbybetweenand(DresnerandBarkan,;Gouldetal.,;Lancefieldetal.,;Moriyaetal.,).Noxemissionswerereportedtodecreasebyfromto(DresnerandBarkan,;Gouldetal.,;Leeetal.,;Moriyaetal.,).Theopeningspeedofthevalveincreasesthevolumetricefficiencyoftheengineandthereductioninvalveliftingdecreasesthefrictionarisinginthevalves(LevinandSchlecter,).WithavariablevalvetimingsystememployingtheEMVsystem,allrelevantparameterscanbecontrolledsimultaneouslyandcompletelyindependently.Therefore,inadditiontoimprovementsinfueleconomyandemissions,engineperformanceisgreatlyimproved(LevinandSchlecter,;Pischingeretal.,).Thevariablevalvetimingsystem,whichisacompletelyelectro-mechanicalsystem,doesnotneedacamshaftandthereforeenablestheproductionofacamlessengine.Asemielectro-mechanicalcamlessengineisoneinwhichonlyintakeoronlyexhaustvalvesaredrivenelectro-mechanically.Camlessenginesystemshaveagreatpotentialastheyhavetheadvantagesofamechanicallyworkingvariablevalvetimingsystemandbecausethecontrolofvalveperformance 1Effectofasemielectro-mechanicalenginevalveonperformanceandemissionsinasinglecylindersparkignitedengine(DepartmentofAutomotiveEducation,KarabukUniversity,Karabuk78050,Turkey)E-mail:ozdalyan@hotmail.com;dogan_oguzhan@yahoo.co.ukReceivedFeb.25,2009;RevisionacceptedJuly7,2009;CrosscheckedNov.8,2009Abstract:Inthisstudy,anelectro-mechanicalvalve(EMV)syste