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Alfa MultiAir engines

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Alfa MultiAir engines

Post by Toad on Fri Oct 16, 2009 12:17 pm

Morning.

Been reading the latest Evo magazine, im which they looked at the new cloverleaf Alfa Mito which has a new 1.4 engine featuring what they call MultiAir. It features a head with vaves laid out like a DOHC head, it's only 1 camshaft though with lobes for both inlet and exhaust, sat above the exhaust valves.

It has a set of pushrods from the inlet lobes to the front of the head. These pushrods work on what is effectively a set of modified hydraulic tappets, there is an electronically controlled valve on each one.

The ECU releases oil from each tappet depending on load, revs, etc. This means that the lift and duration can be adjusted, as well as the timing of the opening, and does allow 2 seperate small valve openings per cycle if need be.

I think this is right, it's been a while since I read the article, but after speaking to Stu today I thought I'd post it up here....
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Re: Alfa MultiAir engines

Post by mrbeige on Mon Oct 19, 2009 5:12 am

The oil must be at a reasonably high pressure to allow that, especially to overcome the force from the valve spring, and indeed the compression stroke. Fairly interesting though.

I'm sure I saw an article somewhere, where they did away with a camshaft completely, and used fast acting solenoids to open and close the valves.

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Re: Alfa MultiAir engines

Post by kevhaywire on Mon Oct 19, 2009 8:15 am

Yeah I read that in Evo too (after I got a hard on looking at the Eagle E Type speedster). Near on 170hp from a 1.4 turbo is very impressive.

Cast your mind back to the Fiat Uno ie Turbo which had the same size engine and turbo and it made 120hp or something, and the Mito uses considerably less fuel too.

I liked the sound of the intake valve pulsing to swirl the incoming air for a better burn.

Mass produced 200hp 1.4 turbo engines aren't far away.

There's nothing like a global warming crisis to force improvements in engine technology Very Happy

Which reminds me, McLaren's new supercar is said to be extremely low on CO2/Kg, so it's defo the way the industry is heading now, which is great news because rather than scrapping high output engines completely - as everyone feared - they're working on extracting the same power from less fuel instead, hurrah!

As I've said before though, all they've got to do is get their **** in gear with E85. A 70% reduction in CO2/Kg right there. And for us modders, 110+ octane and cooler running Very Happy

Stu, yeah it's BMW's Valvetronic or something that is camless. Continously variable intake and exhaust timing. Very cool. Last time I read about it, it was limited to the 1800 petrol engines because the technology wasn't then good enough to be used on their high power 6 and 8 pot engines.

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