14 replies to this topic

[fezzasus]

http://jalopnik.com/...gine-1529865968

 

I bet it's going to take a while before you have this option on the ODBTuner.

[FLD]

Looks like the future.  I've seen various camless designs in the past, each with their own pro's and cons but this seems to have got a lot further than the others.

[fezzasus]

Longevity will still be the critical factor with this. It's difficult to lubricate pneumatic parts and the valve train is a key wear area as it is, this might mitigate the wear, it might make it much more severe depending on implementation.

 

What really needs to happen is a large manufacturer to buy them and initially uses the design to drop fleet average CO2.

[JamesC]

I watched a video on this a few months ago, certainly looks to be the way forward.

 

 

 

[FLD]

One of the versions I saw had no valves either.  It was an odd design.  Imagine a babybel in the port with a hole bored through it off-centre.  This was turned instead of a cam essentially opening the port / closing the port as a tube rather than a valve.  Similar to a ball valve on domestic plumbing.  I imagine this was lubricated like a cam???  the problem with this design was sealing it.  They had some odd seal arrangement which was never really revealed so, given I've seen nothing of it, I suspect its not practical.

[fezzasus]

Isn't that similar to a sleeve valve?

[FLD]

Yes, similar. Looks like a camshaft with holes through it so slightly more conventional looking but the principle is the same

[siztenboots]

Interesting, the Fiat Multiair uses only cams to control air , there is no throttle butterfly. But it still has cams, albeit with a solenoid valve as a hydraulic/mechanical link of the cam's profile.

[CocoPops]

That was going to be my question Steve, how Multiair works/compares etc.

[siztenboots]

exhaust cam is conventional, its just the inlet cam hydraulic that has the extra solenoid control

[fezzasus]

That makes sense, the inlet cam is the mildest in terms of wear so it looks like there could well be durability issues with going to a full solenoid valve train. I'd be interested to see how long these twin air engines last.

[techieboy]

I assume if the valve solenoid fails, there's the equivalent of a valve spring so that it fails "closed"? ETA: Just seen comment 5 on the diagram.

Edited by techieboy, 27 February 2014 - 11:55 AM.

[siztenboots]

what happened to the VX with the variable valve head?

[siztenboots]

interesting site with lots of upgrade info , seems to cover most of the ecotec variants

 

http://www.fmsrperfo...ory&path=20_124

[slindborg]

CvK still looks like a Bond villan