Who needs a cam?

RRich · #11 10-14-2006, 03:05 PM

He He -- Don't we all do that already?

Then why do we pay extra money for "floatation tires?"

RRich · #12 10-14-2006, 03:53 PM

It could be possible to at least partly control the valves by changing the rocker's ratio electronically. Cadillac touched on the idea a few years back with the 4-6-8 to disable cylinders. By changing ratios, overlap, duration, lift etc are changed. Yes all three change at once, but it's better than being stuck with just one lump.

Some high tech race cars are using that technology now in exotic engines.
The fast speed of opening and closing the valve is eliminated, and if something does go wrong, it doesn't "smack" a valve.

We may see that as commonplace in the near future.

TiminMb · #13 10-14-2006, 04:00 PM

How about combining the concept with a spherical rotary valve? Instead of opening into the combustion chamber, it is a ball that rolls and opens the port. It simply spins at half the rpm of the engine and you could vary the phase to the cranshaft is you spun it with an electric motor.

RRich · #14 10-14-2006, 04:28 PM

Now see there? Two heads are better than one!

Why is it I never could find two headded employees?

Come to think of it, my last wife had two heads - one was nasty, the other was mean.

bandhmo2 · #15 10-14-2006, 09:28 PM

Every year there is a nation wide model engine builders gathering. These guys do lots of cool stuff, like one tenth scale Radial aircraft engines that actually run.

I have been told that there is a guy with a small model of a electric valve engine that shows it off every year. From what I have been told it is throttled by changing the valve open time, and can even run as a hit and miss.

The ball valve is A neat idea. It would be kind of like a Junk head engine. These a liner in the cylinder that is moved up and down and rotates to open and close the valve openings which are cut in the side of the cylinder and in the liner.

RRich · #16 10-15-2006, 02:16 AM

The only real problem I see with the ball valve idea - or a rotating cylinder valve, is it's running in the carbon from the burning process. I'd think the carbon would cause fast wear on the sealing surfaces. That was a big problem with the Wankel Rotary engine - the seals dragged across the dirty combustion area.

A regular engine valve tends to self clean the seat every time it closes.

If somehow we could get the carbon out of hydrocarbon fuels it probably would be practical.

Interesting concepts though - keep em coming!

jeepete · #17 10-15-2006, 12:13 PM

[ QUOTE ]
I'd think the carbon would cause fast wear on the sealing surfaces. That was a big problem with the Wankel Rotary engine - the seals dragged across the dirty combustion area.........

[/ QUOTE ]

I'm sure the problem can be overcome. After all the rotary has been and is still in production for nearly 40 years.

[ QUOTE ]
.....If somehow we could get the carbon out of hydrocarbon fuels it probably would be practical.

[/ QUOTE ]

Carbon free Hydrogen fuel has been around forever. Available but not practical for the same reason rotary and/or electric valves are not. Cost vs benefit. Even the relatively simple variable valve control systems in production are cost prohibitive, and they've been around for many years. Just not worth it as long as fuel and breathable air remains cheap.

RRich · #18 10-16-2006, 12:47 AM

""""I'm sure the problem can be overcome. After all the rotary has been and is still in production for nearly 40 years.""""

Yup, and still has the same old problem.

Hydrogen as fuel - yup, carbon free -- but to separate hydrogen from whatever they get it from - usually water - it takes energy. Usually that energy comes from hydrocabon fuels making electricity to separate the water. Not very efficient.

Hopefully someday some other source of energy will be tapped - like sunlight, when it is, the entire world will change.

RickCJ7 · #19 10-16-2006, 03:18 AM

I don't know the mechanical specifics, but the Formula One racing engines have been using an air pneumatic system for the valves. For some reason the mechanics limit those engines to rev up to only 18,500 rpm. That would be just 9,250 cycles for each valve each minute.

#20 10-16-2006, 01:37 PM

While it sounds great...in reality, it's hard to beat mechanical leverage when it comes to effeciency.

But...I think putting effort in that direction is a waste of time....

My idea of the perfect jeep would be all electric with a small effecient turbin as the generator. With a strong electric motor at each wheel you wouldn't need lockers or diff's....