Camless Engine to Possibly Debut in Fiat 500, Alfa Junior in 2009

[hightower99]

Originally Posted by revetec

So what happens when you are at 6,000rpm and have an earth problem. Hope they will all be free running engines in respect to the piston/valves and or use springs as well (but then that'll drop efficiency) but a infinite variable valve timing will be good.

Are you talking about Poppet style valve system or CSRV system?

[Matra et Alpine]

Originally Posted by revetec

So what happens when you are at 6,000rpm and have an earth problem. Hope they will all be free running engines in respect to the piston/valves and or use springs as well (but then that'll drop efficiency) but a infinite variable valve timing will be good.

An electrical failure driving a valve Coates valve woudl be MUCH safer and less expoensive to repair than a spring driven poppet.
So an exhaust and inlet don't open -- so what, the ECU would know of the valve failure and prevent ignition and injection
No issue of piston hitting valve under ALL failure modes.
You'd lose a cylinder .... but coudl still limp home.
Even if it was total failure of all or most, then it's no worse a failure mode than a cambelt -- again the SRV means it's MUCH "safer" as nothing can hit anything

[revetec]

Originally Posted by hightower99

Are you talking about Poppet style valve system or CSRV system?

Of course poppet valves, You don't need solenoids for CSRV! heheheh

[hightower99]

Originally Posted by revetec

Of course poppet valves, You don't need solenoids for CSRV! heheheh

No but we where just talking about an electronically controlled CSRV system that would give it the same amount of control.

Hence why I asked which and why Matra posted that the CSRV system is much safer (due to it not being an interference engine).


To answer you question for poppet valves: the design that is going to be used uses springs to help return the valves so a failure in the solenoid is not that bad unless it got stuck open...

Then it would be bad.

[revetec]

So we are still relying on springs to close the valves?

If so, we have the same rebound time if we use the same spring and the solenoid doesn't add reciprocating mass to the valve.

The benefit then is only varying the valve timing and not about red-line as we have been discussing?

[hightower99]

Originally Posted by revetec

The benefit then is only varying the valve timing and not about red-line as we have been discussing?

That kind of down plays the importance alittle.

They are achieving almost total control over valve timing, duration, and lift.

[revetec]

Originally Posted by hightower99

That kind of down plays the importance alittle.

They are achieving almost total control over valve timing, duration, and lift.

I don't think that the solenoid will control lift. Like an injector, I would think that it is controlled using a duty cycle and is either open or closed which bottoms out at the desired lift. I could be wrong? I can't find out info on the web on this. I'll search a bit more though.

[revetec]

I did find a patent on solenoid operating hydraulic actuators that can control lift rates. Still looking...

[revetec]

Found a system that can control opening and closing rates.

Patent owned by Siemens.

Autospeed article
Solenoid operated engine Valves

[Fiorano]

Valveless valve system has been tested in F1 before- but rules outlawed it...
and Coates Engineering does a valveless or rotary valve type valve cam.... looks cool and sounds good- revs crazy high for a normal thing but some one is keeping the Tech on the downlow for some reason.

[revetec]

I saw a paper on the Coates system from a university doing some work on the system.

Bishop Rotary Valve on a V10 F1 engine?

[Fiorano]

thats the one

[Dave Bowes]

Originally Posted by kigango123

I also heard that the fiat will just be camless on the exhaust valves and at the inlet valves will be operated on a normal camshaft

supposedly it was named E-valve

http://innovation.valeo.com/en/downl..._System_EN.pdf

A careful read of the info on Valeo's web site will show that they are planning to first apply the technology on the intake valve not the exhaust valve. Also they do not claim to have Fiat as a customer. That came from a suggestion in a January 2008 article that said Fiat were believed to be developing a similar system for possible 2009 production.

I have been building EVIC model engines with solenoid opetated valves for about 8 years. I can verify from experience that intake valve control is far easier than exhaust valve control. It is the difficulties with exhaust valve control that is keeping this technology, whether conventional poppet valves like my EVIC engines or desmo like Ford, BMW, etc. have researched, out of production. Anyone really interested in the technology may find my Student Guide of interest.

Dave Bowes