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MultiAir or Multiair is a hydraulically-actuated variable valve timing (VVT) and variable 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 by Fiat Powertrain Technologies, the technology addresses a primary engine inefficiency ...
Variable valve lift (VVL) is an automotive piston engine technology which varies the height a valve opens in order to improve performance, fuel economy or emissions. There are two main types of VVL: discrete, which employs fixed valve lift amounts, and continuous, which is able to vary the amount of lift.
Alfa Romeo was the first manufacturer to use a variable valve timing system in production cars (US Patent 4,231,330). [10] The fuel injected models of the 1980 Alfa Romeo Spider 2000 had a mechanical VVT system. The system was engineered by Ing Giampaolo Garcea in the 1970s. [11] All Alfa Romeo Spider models from 1983 onward used electronic VVT ...
Alfa Romeo was the first manufacturer to use a variable valve timing system in production cars (US Patent 4,231,330). The 1980 Alfa Romeo Spider 2.0 L had a mechanical VVT system in SPICA fuel injected cars sold in the US. Later this was also used in the 1983 Alfetta 2.0 Quadrifoglio Oro models as well as other cars.
The system has the advantage that it is continuously variable rather than switching in at a set speed. Its disadvantage is the complexity of the system and corresponding price. Other systems will achieve similar results with less cost and simpler design (electronic control). For a more detailed description, see the sandsmuseum link below.
Only Multi-Air heads feature electro-hydraulic variable valve timing and lift, although only on the intake side. The system is based on FIAT technology. [5] It utilizes a bore and stroke of 88 mm × 97 mm (3.46 in × 3.82 in) and a 10.0:1 compression ratio. Applications:
Fiat's TwinAir debuted at Internationale Automobil-Ausstellung 2007 in the Fiat Panda Aria concept car. [ 3 ] as an 80 PS (59 kW), turbocharged, CNG-hydrogen mix and gasoline bifuel unit. The production TwinAir engine was launched at the 2010 Geneva Motor Show in 85 PS (63 kW), turbocharged gasoline form and became available later in 2010 in ...
Camless valve trains have long been investigated by several companies, including Renault, BMW, Fiat, Valeo, General Motors, Ricardo, Lotus Engineering who developed electro-hydraulic valve actuation in the late 1980s as a spinoff of their active suspension program (both utilised similar electro-hydraulic actuation and control), Ford, Jiangsu Gongda Power Technologies, and Koenigsegg's sister ...