Hi all, I know this may sound silly...but do multiair engines have a throttle plate? I read somewhere (don't remember where) that this revolutionary engine doesn't have one. Instead intake air goes straight into the cylinders through the valves. Could this be right?..I'm in doubt to believe it.

panmecheng said:

Hi all, I know this may sound silly...but do multiair engines have a throttle plate? I read somewhere (don't remember where) that this revolutionary engine doesn't have one. Instead intake air goes straight into the cylinders through the valves. Could this be right?..I'm in doubt to believe it.

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The MultiAir system controls engine rpm purely by valve opening and duration, it doesn't 'need' a throttle butterfly. However, the induction noise from the open MultiAir intake means an electronically controlled butterfly is used to improve NVH (Noise/Vibration/Harshness) while cruising @ low rpm.

I feel the need to point out here that the BMW Valvetronic engines (introduced from 2001) had no throttle butterfly.
Just as Fiat's system, there is a butterfly, but it isn't used for the throttle unless the valvetronic fails. It is only there as a backup and is fully open during normal engine operation.
So they pre-date Fiat's MultiAir system by a long way.