- Multiair
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Multiair (or Uniair) is an electro-hydraulic variable valve actuation technology controlling air intake (without a throttle valve) in petrol or diesel engines [1]. It is compatible with both naturally aspirated and forced-induction engines.
Multiair technology was patented by Fiat in 2002; it was launched at the 2009 Geneva Motor Show to be available in the Alfa Romeo MiTo.[2] The new engine is produced in Termoli, Italy at the Fiat Powertrain Technologies factory. The 1.4 L Multiair engine won the "Best New Engine of 2010" award.[3]
Contents
Technology
The basic idea, controlling intake valves, works upon the following principle: a valve tappet (cam follower), moved by a mechanical intake cam, is connected to the intake valve through a hydraulic chamber, controlled by a normally open on/off solenoid valve.[4] The system allows optimum intake valve opening schedules.
An example of the gains offered by the MultiAir technology can be seen in the current Alfa Romeo MiTo: the 1.4 JTB engine, without MultiAir, can produce 155 PS (114 kW; 153 hp) and 230 N·m (170 lb·ft) whilst using 6.5 litres per 100 kilometres (43 mpg-imp; 36 mpg-US). With MultiAir, the same engine develops 170 PS (125 kW; 168 hp) and 250 N·m (180 lb·ft), yet only consumes 6.0 L/100 km (47 mpg-imp; 39 mpg-US).
MultiAir engines will increase power (up to 10%) and torque (up to 15%), as well as considerably reduce consumption levels (up to 10%) and emissions of CO2 (up to 10%), particulates (up to 40%) and NOx (up to 60%)[2][1] when compared to a traditional petrol engine. The system also provides smoother cold weather operation, more even torque delivery and no engine shake at shut-off.[5]
The Multiair technology took over a decade to develop. The vice president of Fiat Powertrain Research & Development Rinaldo Rinolfi led the team who developed the technology. Development costs were over $100 million.[6] There was also delay in development, in the time (2000-2005) when Fiat was in partnership with General Motors.
Other systems
More advanced, fully camless valvetrain systems are under development, but are not yet production-ready.[7] The Valvetronic system used by BMW allows 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.
See also
Notes
- ^ a b ""Best new engine 2010"". "International Engine of the Year". http://www.ukipme.com/engineoftheyear/winners_10/bestnew.html. Retrieved 2010-09-15.
- ^ a b "「MultiAir」 is launched on the Alfa Romeo MiTo". alfaromeopress.com. http://www.alfaromeopress.com/index.php?method=news&action=zoom&id=4453&format=print. Retrieved 2009-06-18.
- ^ "Fiat's 1.4-liter turbocharged Multiair powerplant wins "Best New Engine of 2010" award". green.autoblog.com. http://green.autoblog.com/2010/06/30/fiats-1-4-liter-turbocharged-multiair-powerplant-wins-best-new/. Retrieved 2011-01-22.
- ^ "The Fiat Multiair Technology: how it works". fiatgroupautomobilespress.com. http://www.fiatgroupautomobilespress.com/index.php?method=cartelle&action=article&id=10457&format=print. Retrieved 2009-06-29.
- ^ "Multiair". fiatgroup.com. http://www.fiatgroup.com/en-us/innovation/crf_activities/prt/Pages/Multiair.aspx. Retrieved 2009-06-29.
- ^ "Fiat retrofits Chrysler engine, shelves 『dinosaurs』 to save gas". pittsburghlive.com. http://www.pittsburghlive.com/x/pittsburghtrib/business/s_631378.html. Retrieved 2009-06-29.
- ^ "Valeo has customers for camless engine with "smart valve actuation"". autobloggreen.com. http://www.autobloggreen.com/2006/12/12/valeo-has-customers-for-camless-engine-with-smart-valve-actuati/. Retrieved 2009-06-29.
- This article incorporates information from the revision as of 2009-06-29 of the equivalent article on the Italian Wikipedia.
External links
Categories:- Engine technology
- Valve timing tradenames
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