MultiAirorMultiairis a hydraulically-actuatedvariable valve timing(VVT) andvariable valve lift(VVL) engine technology enabling "cylinder by cylinder, stroke by stroke"[1]control of intake air directly via a gasoline engine's inlet valves. Developed byFiat Powertrain Technologies,the technology addresses a primary engine inefficiency: pumping losses caused by restricting intake passage by the throttle plate that regulates air feeding the cylinders.[2]
Fiat S.p.A.,now known asStellantis,launched MultiAir in 2009, employing a proprietary electro-hydraulic system to precisely control air intake without athrottle valve[3]to increase engine power and torque, reduce fuel consumption, reduce emissions, and improve engine operation, offering "a more controllable flow of air during the combustion cycle in comparison with mechanical VVT systems."[4]The technology allows engines to be lighter and smaller while reducing pump losses. It can be adapted to existing engines by replacing the camshaft with the MultiAir system, thus requiring a new head only.
MultiAir was licensed to theSchaeffler Groupin 2011, which also markets the system asUniair.[5]Schaeffler began supplying Uniair systems in 2017 toJaguar Land Rover,branded asIngeniumtechnology.[6]
Compatible with both naturally aspirated and forced-induction engines, MultiAir technology was patented byFiatin 2002 and was launched at the 2009 Geneva Motor Show in theAlfa Romeo MiTo.[7]1.4 L MultiAir engines for global markets are manufactured inTermoli,Italyat theFiat Powertrain Technologiesfactory and the FCA'sDundee Engine Plant(formerly ofGlobal Engine Alliance's GEMA manufacturing branch), with critical systems manufactured and assembled bySchaeffler Group.[5]
In 2010, the 1.4 L MultiAir engine won theInternational Engine of the Year[8]as well asPopular Science'sBest of What's New.[1]In the same year, the FiatSGEengine (0.9 L turbocharged and 1.0 L naturally aspirated TwinAir units), also using MultiAir technology, was launched in the Fiat 500. It is produced inBielsko-Biała,Poland.It was namedBest New Enginein 2011.[9]
Both FIRE and SGE units are equipped with MultiAir and use indirect fuel injection.
TheGME(Hurricane) andGSE(FireFly) MultiAir II engines, which use direct fuel injection, were first made available in 2016.
Technology
editHow it works
"The MultiAir system is elegantly simple. An electrohydraulic actuator, a high-response, electronically activated solenoid—controls the pressure applied to hydraulic fluid (engine oil drawn from the sump) that fills a thin passageway that connects the intake valves and the camshaft. The solenoid valve regulates the amount of oil pumped by the cam action to either the valve or a bypass reservoir.When pressurized, the hydraulic line behaves like a solid body and transmits the lift schedule imparted by the intake cam directly to the intake valve. When the solenoid is disengaged, a spring takes over valve actuation duties.
This electrohydraulic link allows independent operation of the two components, which enables near real-time control over the valve lift profiles, said Bernard. Whereas a closed solenoid normally transmits the pressure generated by the camshaft’s intake profile to the valve, an open solenoid breaks the hydraulic link between cam and valve, decoupling their operations. "[10]
Society of Automotive Engineering, 2010
For variable valve lift, competing technologies (e.g., Honda'sVTECand BMW'sValvetronic) use electromechanical concepts, achieving valve lift variation via dedicated mechanisms; it can also be combined withcamshaftphasers to allow control of both valve lift and phase. In contrast, MultiAir uses managed hydraulic fluid to provide variable valve control.
Control of a MultiAir engine's intake valves works via a valvetappet(cam follower), moved by a mechanical intake cam, which is connected to the intake valve through a hydraulic chamber, controlled by a normally open on/off solenoid valve.[11]The system allows optimum timing of intake valve operation.
MultiAir technology can increase power (up to 10%) and torque (up to 15%), as well as reduce consumption levels (up to 10%) and emissions ofCO2(up to 10%), particulates (up to 40%) andNOx(up to 60%)[3][7]when compared to a traditional petrol engine. The system also provides smoother cold weather operation, greater torque delivery, and no engine shake at shut-off.[12]
Development
editResearch on critical related technologies started in the 1980s when engine electronic control reached market maturity. MultiAir was developed over ten years at Fiat's Centro Ricerche Fiat (CRF) in Orbassano outside Turin,[13]after a five-year delay during Fiat's 2000-2005 partnership with General Motors.[14]The vice president of Fiat Powertrain Research & Development, Rinaldo Rinolfi, led the team who developed the technology at a cost of over $100 million.[15]
Other systems
editMore advanced, fullycamlessvalvetrain systems are under development but are not yet production-ready.[16]TheValvetronicsystem used byBMWallows the valve timing and lift to be varied, but not the cam profile. The ability to vary the latter is characteristic of camless and the MultiAir systems.
Applications
editSee also
editReferences
edit- ^ab"Fiat's Multiair engine wins Popular Science Award".Popular Science via Allpar. November 17, 2010. Archived fromthe originalon March 3, 2016.RetrievedMay 31,2016.
- ^Mark Gillies (October 2009)."Fiat's Multiair Valve-Lift System Explained".Car and Driver.
- ^ab"Best new engine 2010"."International Engine of the Year".Archived fromthe originalon 2012-06-30.Retrieved2010-09-15.
- ^Mike Hanlon (March 7, 2009)."Fiat releases MultiAir engine technology – is this a fundamental internal combustion engine design breakthrough?".Gizmag.
- ^abDavid Zoia (March 7, 2011)."Schaeffler Expects Other Takers for MultiAir Technology".Wards Automotive. Archived fromthe originalon August 6, 2016.RetrievedMay 30,2016.
- ^springerprofessional.de:Drivetrain | UniAir Valve Control for Ingenium Petrol Engine | springerprofessional.de,accessdate: 27. January 2018
- ^ab"“MultiAir” is launched on the Alfa Romeo MiTo ".alfaromeopress.Retrieved2009-06-18.
- ^"Fiat's 1.4-liter turbocharged Multiair powerplant wins" Best New Engine of 2010 "award".green.autoblog.Retrieved2011-01-22.
- ^"Fiat 875cc TwinAir".ukipme.Archived fromthe originalon 2013-02-05.Retrieved2012-01-03.
- ^Steven Ashley (October 7, 2010)."Inside Fiat's innovative MultiAir system".Society of Automotive Engineers.
- ^"The Fiat Multiair Technology: how it works".fiatgroupautomobilespress.Retrieved2014-07-28.
- ^"Multiair".fiatgroup.Retrieved2009-06-29.
- ^WebCite query result:WebCite query result,accessdate: 16. June 2016
- ^The Boston Globe:Fiat hopes tech will make Chrysler deal work - The Boston Globe,accessdate: 16. June 2016
- ^"Fiat retrofits Chrysler engine, shelves dinosaurs to save gas".pittsburghlive.Retrieved2009-06-29.
- ^"Valeo has customers for seamless engine with" smart valve actuation "".autobloggreen.Retrieved2009-06-29.