Posted on 10/19/2005 10:59:55 AM PDT by Jack of all Trades
Good point. Each piston stroke only turns the crankshaft 1/3 of a revolution, so it'd take three times as many strokes to produce a given rpm. It's like it has a built in gear reduction. But couldn't you get around this by gearing it back up through the transmission?
maybe i'll put one in my X1/9
NSU was the first company to use the Wankel. Subsequent to Mazda's implementation, General Motors bought - but never used - rights.
The original Wankel problem was seal wear. Later, problems centered on emissions - but, this was, again, seal-related. Looking at rated reliability and service costs, I suspect that seals are still a problem. It's a very pleasing engine to drive, but, so far, just not practical; a Mazda salesman recently cautioned me that the latest model should be allowed a few minutes to warm up - get real!
I agree. It seems to be a reinvention of the wheel.
It would be interesting to see and hear one running though.
Yes it would.
"What's wrong with the Wankle? Why did only Mazda use it?"
The dying gasp of Norton motorcycles was a wankel powered bike.
I have an '84 RX7 with 147,000 miles on it. I've never rebuilt it and I drive it regularly. When it was new in '84 it was quicker to 60 mph than the '84 Corvette. I'll stick with my 1.3 liter Rotary. Hummmmmmmmmmmmmmmmm!
You probably just hit a couple of nails squarely on the head. I work with very high pressure fuel pumps that look stikingly similar to this concept. Most of the working internals are superfinished tool steels or ceramic. Big bucks.
As RPM increases, the demands on the injectors, valvetrain and ignition system will increase at 3X the rate of a standard engine. Keeping everything moving, timed and controlled at high RPM is probably going top be difficult (read: expensive).
bump for later. Looks cool.
More like an X-6, I think...
Another way to achieve zero side loading on pistons is with dual counter-rotating crankshafts and two con rods to each piston, which isn't as bad as it sounds as they can be made half as big.
There's hundreds of ideas out there for improving the internal combustion piston engine, some of which might work, but they all require massive amounts of R&D money to ever be competitive with the current designs, in which we already have billions of dollars in tooling to produce.
So we use lower compression ratios so we can burn crappy unleaded fuel which has a much lower flash point than fuels of the past. Notice how gas seems to go bad after sitting for a month or two? I swear, it's half water. (which helps control detonation)
You could raise compression a bit more, and get better power if you use alcohol blended gas, but you would have to use high percentage blends, 25% or more, re-jet carbs or recalibrate fuel injectors. You would loose fuel efficiency because you need more alcohol in the fuel air mixture to prevent meltdowns. So the option is low compression engines to burn todays crappy gas.
Yep, the usual achille's heel of unconvential IC engine designs: parts, materials and manufacturing techniques that are either non-existent or extremely expensive. Too much so to overcome the inertia of conventional designs.
Would stress really go up? Sure you have a large lever arm when the piston rolls over the nose of the cam and starts pushing it down, but it seems that there is a large bearing area available. In a standard IC engine all that force is transmitted through a half inch wrist pin and a two inch rod journal.
I just spoke with another engineer here and apparently Revetec has been hawking this engine for a couple of years without any real bites. Cool tech, high power density, but expensive.
On another note, I'll bet things could get interesting in a hurry if one of these engines develops a misfire.
I suppose, But I don't think I've ever turned my tires at greater than 2000 RPM.
Hmmm. Tires, say, 24" diameter. 75 inches per rotation. 63360 inches per mile. About 840 rotations per mile. Two miles per minute at 120 MPH. 1700 RPM.
Maybe one could skip the transmission entirely if the low end torque is high enough?
cool stuff ping
I had a 75 X1/9. Worst engineered car I've ever owned! The pistons were in backwards!.........
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