Twin Air: The Revolution

Discussion in 'Emerging Technologies' started by Dhhawal, Aug 9, 2011.

  1. Dhhawal

    Dhhawal New Member

    Apr 26, 2011
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    Twin Air is the name that Fiat Power Terrain Technologies has decided to use for an engine which displaces 900cc and is currently part of the 500 lineup, before you start laughing though, you must understand that this engine is understood by many critics as the 'gamechanger' of modern SI engines, the 'daddy' of engine down-sizing..its already has a pretty kitty of awards under its belt, its because this puny engine with two small arm-sized cylinders produces; in its least powerful form:85 bhp..yes thats right..its not a typo.

    Yes it is turbo charged, but have you heard of turbo maruti 800, well i haven't, and even if something like that existed I am sure it couldn't be as powerful as this unit.

    The technology
    TwinAir takes its name from Fiat Powertrain Technologies’ (FTP) MultiAir technology. It basically ensures air control in spark ignition engines without using the throttle valve. Air, as you know, is one of the main ingredients needed by an engine to run. In conventional engines, the volume and pressure of the air in the cylinders is controlled with the help of the aforementioned throttle valve. This configuration makes the engine lose about 10 per cent of input energy, used to pump the air from a lower to a higher intake pressure.

    In MultiAir’s case, Fiat implemented an electro-hydraulic valve actuation system (inspired from the Common Rail technology), which uses a high pressure chamber, fitted in between the cam and engine intake valve. The volume of the oil inside the chamber can by adjusted through an on-off solenoid valve controlled via its own electronic unit.
    By doing so, Fiat’s system is capable of controlling the air mass and its pressure in each cylinder and at every stroke of the pistons.

    The engine
    The TwinAir engine has an exact displacement of 875cc. It has two cylinders, with eight valves each and a 10:1 compression ratio. FTP, the masterminds behind the two cylinder unit, say they have precisely optimised the unit to ensure minimal engine friction. The turbocharged engine gets duel into its pistons thanks to a multipoint injection system. All its components are so light, the entire unit weighs only 85 kg.
    The unit is capable, in its least powerful version, of developing 85bhp at 5,500 rpm. The total torque developed by TwinAir is 155 Nm at 2,000 rpm. The torque is being kept at constant levels until the engine reaches 3,500 rpm.

    Being so small, the engine has remarkable fuel consumption figures. In the Fiat 500, the engine uses up to 4.9 litres per 100 km (48 mpg) in the city for the manual transmission version and 4.6 litres per 100 (51 mpg) for the unit paired with a Dualogic gearbox.
    This achievements in fuel consumption are not the engine’s merit alone. They are also supported by the employment of a start/stop technology fitted standard on the 500 TwinAir. In the manual transmission version, the Gear Shift Indicator tells the driver exactly when to change gears so that it gets the most out of the unit with as little fuel as possible.
    Having such low fuel consumption figures, the unit also emits less CO2 into the air. Some 30% less, Fiat calculated, than even bigger engines with the same output. The carmaker plans to turn the unit into a hybrid as well, by slapping a 5 kW electric motor on it. This would make it even much more frugal, giving the TwinAir a fuel consumption figure of 2.3 litres per 100 km (100 mpg) and emission levels in the 70 grams per kilometre range.

  2. galemack

    galemack New Member

    Feb 15, 2013
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    CVT uses a fluid to create a continuously variable transmission. A variable-displacement pump is used to pump fluid between two hydrostatic motors. One motor is connected to the engine, the other to the drive shaft. The engine side houses the pump. Technically speaking, the pump converts rotational energy from the engine into fluid form, which then is pumped to

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