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ollie 03-14-2001 11:56 AM

Re: Super Valves
My guess is that it's electro-magnetic in nature, controlled by a system similar to electronic ignition.

granny 03-14-2001 12:05 PM

Re: Super Valves
Ducati was rumored to be working on such a thing (i would be surprised to learn that Honda wasn't). Computer controlled cam timing would be quite nifty - it would make the mechanically based variable duration/timing system on the new Porsche turbo seem mickey mouse (Road and Track had a write up on the Porsche system). One problem - with solenoids/whatever controlling the valves, Ducati could no longer be distinguished by their "desmo" trademark. C'est la vie.

hackfu 03-14-2001 12:09 PM

Re: Super Valves
Funny you should mention Honda. Its rumoured that Honda will be licensing the electro-valve technology from Renault!

I don't know how much truth there is to this statement, however. Just something to look out for I suppose.

GoFaster 03-14-2001 12:17 PM

Re: Are Super Valves Headed for Motorcycles?
Electromechanical valves do indeed use solenoids to control the valves. The main advantage is that it allows valve timing to be varied almost indefinitely. It has huge implications - think of Honda's VTEC system taken far, far further. Valve timing can be immediately changed to the best timing for any operating condition ... for maximum power at full load, or for best efficiency and emission control at part load.

There are two problems with all this. One of them has been the power consumption of the solenoids. To solve this, some systems use hydraulics (basically engine oil pressure) to do the actual work of moving the valve, with small solenoids controlling what the hydraulics are doing. Anyone out there with a Ford Powerstroke diesel? It's rather similar to the way the HEUI (hydraulically powered, electronically controlled, unit injector) system works for the fuel injection on those. (In fact, Navistar is working on a "camless diesel" which applies this principle to the valvetrains on their next generation diesel engines. No more dirty diesels - it's capable of reducing emissions on those engines to practically nil.)

The other problem has been getting the system to work fast enough. Making it work on a 4000rpm diesel is one thing - making it work on a 14,000 rpm gasoline engine is quite another. It may come eventually, but it looks like the first production application will be Navistar's diesel, and it is still a few years off.

It may happen in Formula 1 sooner than that, for the simple reason that those teams have a LOT of money available. It's a different story when trying to make something that is cost-effective.

Anyway, it's certainly all very interesting.

SamBlob 03-14-2001 12:59 PM

Re: Are Super Valves Headed for Motorcycles?
Problem #1: High electric/hydraulic loads: thereby requiring really heavy-duty alternator or oil pump, or air compressor if an electro-pneumatic system is used instead of the proposed electro-hydraulic system. How much energy is used to turn a camshaft? Helical gears, chains or belts turning a shaft should be more efficient than massive alternators or oil pumps, shouldn't they?

Problem #2: Electrically- or electrohydraulically activated valves will work best on low-speed, high torque engines where valve timing is slower and can be more easily controlled. Meaning that this technology is best suited to Harley-Davidson, the least likely manufacturer to use it.

gt750 03-14-2001 01:25 PM

Two Stroke Fever!!!
I'll take an Orbital type engine anyday! I still NEED a four cylinder 1000c.c. two stroke. It'll be light, cheap and clean. Also will kick any four stroke's butt!

v2-90 03-14-2001 01:32 PM

Re: Super Valves
Unless they had 2 solenoids - one for opening the valve and another to force close the valve

they could call it desmoelettrico or desmoelettro-meccanico



hackfu 03-14-2001 01:34 PM

Re: Are Super Valves Headed for Motorcycles?
If I'm to understand correctly, Benetton has already ran and tested their electro-magnetic valve system with lap times that are right along side those produced with their Supertec Playlife engine. The Supertec engine already had a year of racing development. So needless to say, for a brand new engine technology to be immediately competitive is very promising.

SezaGeoff 03-14-2001 02:08 PM

Re: Are Super Valves Headed for Motorcycles?
The electrical load problem is one of the reasons that BMW (among others ) is looking to change to a 42 volt system. I believe that they have announced a 4 cyl. engine that uses the intake valves instead of throttles to control the engine speed - and this uses continuously variable timing.

DataDan 03-14-2001 02:37 PM

Re: Are Super Valves Headed for Motorcycles?
When the Honda V5 GP motor was announced, I was curious if it might incorporate tricks in the valve train, such as the pneumatic springs used in F1 (AFAIK, F1 uses conventional camshafts with pneumatic valve springs, not pneumatic actuation). After close inspection of the photo, I'd guess not. In fact, it appears rather ordinary (except, of course, for the extra spark plug in the front cylinder head ;-).

Using the oil filter for scale, it appears to be about 12 inches wide, roughly the same as the VFR/RC30/RC45, with front bore center spacing of 85-90mm, precluding massively oversquare (2:1 bore/stroke ratio) F1 dimensions. A 990cc five with a more typical 1.6:1 ratio, about same as current Superbikes, would have a 74mm bore, which would fit comfortably within the apparent bore spacing.

The resulting 46mm stroke--same as the GSXR750--would allow revs up to 16,500 assuming 5000 ft/min mean piston speed. That could be supported by conventional valve springs rather than requiring F1

With ample power on hand now and no practical limit on displacement for street bikes, I don't see high revs and the attendant valve train gizmos as an economical performance development strategy. However, variable valve timing--and perhaps even electo-magnetic actuation--could be the key to maintaining performance under increasingly strict emission regulations.

As I understand it, intake/exhaust valve overlap--a period between exhaust and intake strokes when both valves are open simultaneously--confers considerable power gain at peak RPMs but dirties the exhaust with unburned hydrocarbons at lower revs. Variable valve timing, whether mechanical like Honda's VTEC or something more exotic, might permit the relentless pursuit of horsepower to continue at environmentally friendly emission levels.

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