VVL and throttle valve

[calicoe]

Hi again,

Another mechanical doubt.
Reviewing some technical documents for the translation, I've remembered one interesting feature of 2 of the VVL systems available (and also other, but these 2 are the ones I better know): BMW's Valvetronic and FIAT's Multiar. And is that both of them lacks of throttle valve, as they both control the air intake with the intake valves.
At full loads there's no benefit from lacking of the throttle body but at partial loads, the valve offers some drag to the air.
According to both BMW and FIAT, it results in a 10% improvement in fuel economy.

Now if I design a VVL or VVT+VVL engine, I must still select what kind of throttle (simple or 1 per cylinder) I want to add.

Do you have taken this into account for the engine designer revamp?

Thanks!

PD: it's not true at all because these systems does have throttle valve but it's installed only in case of failure of the VVL system or for diagnosis.
This article it's quite good showing both systems: http://www.germancarforum.com/community/threads/fiat-multiair-in-detail-incl-bmw-valvetronic-comparison.30583/

[Killrob]

Basically there is NO standard at all, so we just throw them all in a big sack, hit it with a stick a few times, then put it into the oven for a few minutes and then serve it cut up in two parts as VVT and VVL... we are not considering different throttle action for those systems, this would just make it too complex (exceptions to the rule don't make for transparent gameplay).

In the revamp you are able to choose between VVT - intake valves only, VVT all, and VVL. That covers most systems and remains simple enough.

[xABSOLUTIONx]

what about VVL on intake only? e.g. Honda's SOHC VTEC

[Daffyflyer]

what about VVL on intake only? e.g. Honda's SOHC VTEC

This will be an option in the revamp

[T16]

Note he said VVL and not VVT.

[Daffyflyer]

Note he said VVL and not VVT.

So he did.. nope then, nothing for that.

[HashiriyaR32]

Wouldn't Valvetronic and Multiair be CVVL instead of the "dual cam profiles" VVL?

[T16]

Yes it would, and Automation doesn't do those either. Funnily enough the Multiair is intake only CVVL.

[xABSOLUTIONx]

if i ask politely enough, will we get VVL on intake only as an option?

[Killrob]

No, that feature needs to be cut, because I can feel it creeping... gotta stop somewhere

[calicoe]

Yes it would, and Automation doesn't do those either. Funnily enough the Multiair is intake only CVVL.

Yes, at this moment the Multiair module is too big to install it at both intake and exhaust. The same reason for not installing direct injection: not enough space at the camshaft.
It's expected that the next evolutions of the systems will improve the size issue.