Multiair
Encyclopedia
Multiair is an electro-hydraulic variable valve actuation technology controlling air intake (without a throttle valve) in petrol or diesel engines . 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
. 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.
valve through a hydraulic chamber, controlled by a normally open on/off solenoid valve.
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 and 230 newton metre whilst using 6.5 L/100 km. With MultiAir, the same engine develops 170 PS and 250 newton metre, yet only consumes 6 L/100 km.
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%) 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.
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. There was also delay in development, in the time (2000-2005) when Fiat was in partnership with General Motors.
valvetrain systems are under development, but are not yet production-ready. 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.
Multiair technology was patented by Fiat
Fiat Automobiles
Fiat Automobiles S.p.A. is an Italian automaker which produces Fiat branded cars, and is part of Fiat Group Automobiles S.p.A.. This is a subsiadiary of Fiat S.p.A., the largest automobile manufacturer in Italy...
in 2002; it was launched at the 2009 Geneva Motor Show to be available in the Alfa Romeo MiTo
Alfa Romeo MiTo
The Alfa Romeo MiTo is a three door sporty supermini officially introduced on June 19, 2008, at Castello Sforzesco in Milan, with an international introduction at the British Motor Show in 2008. The car was available in all Alfa's major markets in stages from July...
. The new engine is produced in Termoli
Termoli
Termoli is a town and comune on the Adriatic coast of Italy, in the province of Campobasso, region of Molise. It has a population of around 32,000, having expanded quickly after World War II, and it is a local resort town known for its beaches and old fortifications...
, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
at the Fiat Powertrain Technologies
Fiat Powertrain Technologies
The Fiat Powertrain Technologies is a part the Fiat Group, which includes all the activities related to powertrains and transmissions to Fiat Automobiles Iveco , Centro Ricerche Fiat and Elasis....
factory. The 1.4 L Multiair engine won the "Best New Engine of 2010
International Engine of the Year
The International Engine of the Year is an annual competition for automotive industry internal combustion engines, judged by a panel of automobile journalists from around the world. It is organised by the United Kingdom's largest technical motoring, aerospace and traffic management publication...
" award.
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 intakevalve through a hydraulic chamber, controlled by a normally open on/off solenoid valve.
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
Alfa Romeo MiTo
The Alfa Romeo MiTo is a three door sporty supermini officially introduced on June 19, 2008, at Castello Sforzesco in Milan, with an international introduction at the British Motor Show in 2008. The car was available in all Alfa's major markets in stages from July...
: the 1.4 JTB
Fully Integrated Robotised Engine
The FIRE is a series of automobile engines from Fiat. It was designed by Italian design firm Rodolfo Bonetto . It is constructed by robot assembly plants to reduce costs....
engine, without MultiAir, can produce 155 PS and 230 newton metre whilst using 6.5 L/100 km. With MultiAir, the same engine develops 170 PS and 250 newton metre, yet only consumes 6 L/100 km.
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
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
(up to 10%), particulates (up to 40%) and NOx
NOx
NOx is a generic term for the mono-nitrogen oxides NO and NO2 . They are produced from the reaction of nitrogen and oxygen gases in the air during combustion, especially at high temperatures...
(up to 60%) 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.
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. There was also delay in development, in the time (2000-2005) when Fiat was in partnership with General Motors.
Other systems
More advanced, fully camlessCamless
Most four-stroke piston engines today employ one or more camshafts to operate poppet valves. The lobes on the camshafts operate cam followers which in turn open the poppet valves. A camless uses electromagnetic, hydraulic, or pneumatic actuators to open the poppet valves instead...
valvetrain systems are under development, but are not yet production-ready. The Valvetronic
Valvetronic
The Valvetronic system is a variable valve timing system to offer continuous and precisely variable intake valve lift, from ~0 to 10 mm, and duration. It typically works in conjunction with the independent Double VANOS system that continuously varies the timing...
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
- Fiat FIRE engineFully Integrated Robotised EngineThe FIRE is a series of automobile engines from Fiat. It was designed by Italian design firm Rodolfo Bonetto . It is constructed by robot assembly plants to reduce costs....
- CamlessCamlessMost four-stroke piston engines today employ one or more camshafts to operate poppet valves. The lobes on the camshafts operate cam followers which in turn open the poppet valves. A camless uses electromagnetic, hydraulic, or pneumatic actuators to open the poppet valves instead...
- ValvetronicValvetronicThe Valvetronic system is a variable valve timing system to offer continuous and precisely variable intake valve lift, from ~0 to 10 mm, and duration. It typically works in conjunction with the independent Double VANOS system that continuously varies the timing...
- Variable valve timingVariable valve timingIn internal combustion engines, variable valve timing , also known as Variable valve actuation , is a generalized term used to describe any mechanism or method that can alter the shape or timing of a valve lift event within an internal combustion engine...