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

[lightweight]

The desmo system was invented in order to prevent valve bounce at high RPM.

The camless motors have a totally different goal. They reduce emission, fuel consumption and have a slight bump in power for any given engine speed. They are the first step towards auto-ignition petrol engines.

The desmo still has the same restrictions in infinitely variable valve actuation as any engine running cams.

[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

[lightweight]

The e-valve system talks about magnetic valve actuation.
This is totally different to the system developed by Lotus Engineering / Eaton Automotive.

Will today's cars be able to support the 42 Volt required?

[Cyco]

42V or higher would be far better for today's cars with their huge numbers of sensors and motors than 12V

[2ndclasscitizen]

Originally Posted by Matra et Alpine

Not at all.
Ducati are outspending on engines by a order of magnitude
An engine lasts one race ... not after a race needs stripped ... but after a race the running gear is worn out and replaced -- FULLY

That's in SBK, where they've had to push the old 999 to the limit.

Originally Posted by Matra et Alpine

No, the engine isnt' the most powerful.
The problem others are having is Ducati run their engines in big-bang mode and it reacts like a twin and they've more experience on running electronics to control the wheel pulses.

Ducati run a screamer engine, because they've got more revs from having Desmo. I've got a good article on it, I'll scan it when I get home.

[Kitdy]

Originally Posted by 2ndclasscitizen

That's true, but it's only a new technology, and has only been developed for road car usage. I'd say once it can be miniaturised and made to run at high rpm it'll find it's way to F1.

There's better tech than valve springs now anyway. Desmo FTW.

What is desmo? Desmondric (spelling) valves?

[kingofthering]

Originally Posted by Kitdy

What is desmo? Desmondric (spelling) valves?

It's a typical ICE without the springs.

[2ndclasscitizen]

Originally Posted by Kitdy

What is desmo? Desmondric (spelling) valves?

Rather than the normal actuation system, where the cam pushes the rocker which pushes the valve open then the spring pulls it closed, in desmo a second rocker arm is actuated by the cam, pulling the valve closed. It reduces frictional losses in the valve train (i.e the cams having to push against a spring) and allows better control over valve opening and closing at high rpms.

Desmo race bikes don't have springs, road ones do have springs, mostly to help starting.

Desmodromic valve - Wikipedia, the free encyclopedia

[Kozy]

Strange that Fiat have decided to only use this technology on the exhaust valve, I would have expected it to be easier to implement on the intake side due to the actuator not having to fight against combustion pressure to open, as well as working in a lower temp area. I guess precise control over the exhaust valves offers the better emmissions though.

A full on performance system of this kind would be awesome, you could have a 1 litre engine with the fuel consumption and driveability of your nans micra, and the power and aggression of a Hyabusa in one unit, with no compromises.

I wonder if it would be better than the Coates SRV design?

[hightower99]

Originally Posted by Kozy

A full on performance system of this kind would be awesome, you could have a 1 litre engine with the fuel consumption and driveability of your nans micra, and the power and aggression of a Hyabusa in one unit, with no compromises.

Haha not quite...

Originally Posted by Kozy

I wonder if it would be better than the Coates SRV design?

Two completely different things....

One is an actuation system for poppet style valves the other is a completely different type of valve...

Off the top of my head I can't really think of a way to achieve the same controlability with CSRVs...

[Matra et Alpine]

Originally Posted by hightower99

Off the top of my head I can't really think of a way to achieve the same controlability with CSRVs...

Come on, ht, it's dead obvious and simple

Because the SRV doesn't encounter the hige forces that openeing and closing a poppet valve takes then it's perfectly feasible to do a complete control-by-wire system with an independant stepper motor on each individual Coates valve. You want ULTIMATE control, then you coudl shut down cylinders by leaving the valves "open" and you can infinitaly variy opening and overlap -- coz with a stepper then roation speed does not have to be consistent Using the valve as the rotor in a motor driven from external field control is also a neat way to do it.

[Kozy]

Originally Posted by hightower99

Haha not quite...

Two completely different things....

One is an actuation system for poppet style valves the other is a completely different type of valve...

I do realise that, what I'm saying is, if both were destined to make it in mainstream vehicle in the future, which would be better. The probalem with solenoid valves is there is still a poppet valve obstructing the airflow in the port.

[hightower99]

Originally Posted by Matra et Alpine

Come on, ht, it's dead obvious and simple

Because the SRV doesn't encounter the hige forces that openeing and closing a poppet valve takes then it's perfectly feasible to do a complete control-by-wire system with an independant stepper motor on each individual Coates valve. You want ULTIMATE control, then you coudl shut down cylinders by leaving the valves "open" and you can infinitaly variy opening and overlap -- coz with a stepper then roation speed does not have to be consistent Using the valve as the rotor in a motor driven from external field control is also a neat way to do it.

I honestly returned to this thread to post almost the same idea (very close to your last sentence anyways), saw that you beat me to it, said D'uh out loud

I would be worried about the speed (transient response to be precise) of the stepper motors (say you shut down a cylinder (by stopping the valves) and then needed to turn it back on at 5000RPM?) Probably not that big of a problem. As what the valves are doing doesn't matter much until fuel and spark are turned on.

[hightower99]

Originally Posted by Kozy

I do realise that, what I'm saying is, if both were destined to make it in mainstream vehicle in the future, which would be better. The probalem with solenoid valves is there is still a poppet valve obstructing the airflow in the port.

My vote goes for CSRVs controlled seperately and directly by field control (ala magnetic train track)

as proposed by Matra

[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.