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Engineering/Technical Ask technical questions about cars. Do you know how a car engine works?
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Old 11-09-2001, 04:03 PM   #31
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A Wankel Rotary Engine spins the output shaft 3x faster than the rotor in the engine. The output shaft in a rotary engine works like a crank in a piston engine. I'm not sure where the rpm's are read on a rotary engine. I always thought it was at the output shaft and the rotor spun three times less than that. But it could be the other way around.

I've been around engines for quite some time...but a rotary is a whole different animal.

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Old 11-12-2001, 10:42 AM   #32
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You've got a point about the rotor in the Wankel engine not running at the same rotation as the shaft. But the engine speed is still measured by the rotation of the shaft, not the number of times the rotor goes around.

The rotor does move once around the engine for every (I'm assuming you're right on the ratio) three times the output shaft moves. A gear on the output shaft moves around a geared ring inside the rotor, therefore it takes more turns of the output shaft to make one revolution of the rotor.
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Old 11-12-2001, 12:01 PM   #33
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exctly....so the point made previously about the engine spinning 3x faster than they RPM's is wrong. IF the RPM's are measured at the shaft (which seems right to me) and it's spinning 3 times faster (which is right) then the rotor....it's the fastest spinning thing in the car. So at 9000rpm...the rotor is spinning at 3000RPM. Nothing is spinning at 27K.

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Old 11-12-2001, 02:42 PM   #34
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That's the way I see it.
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Old 11-13-2001, 06:31 AM   #35
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Must feel weird when you open the throttle wide, and it feels like you have an obliterated clutch melting at the burn of high spinning engine--but the car still charges forward. Hmmm... can't wait to take a test drive behind the wheel of an A6 Multitronic next year or so. That thick linked chain belt they use looks pretty unusual.
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Old 11-13-2001, 09:23 AM   #36
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It's almost eerie when the vehicle moves and accelerates and the engine stays at a steady speed. I enjoy pointing it out to (non-car) people and they just look at the gearshift in awe. When you need more power, the ratios will adjust and the engine will rev, but under light load, it doesn't have to.
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Old 11-13-2001, 09:30 AM   #37
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Wouldn't it be kinda cool to have a manually adjustable CVT? as a knob or lever? that way you can match the way you drive and handle the pedal with your gearing, and you don't have to rely on the car to be able to 'read' into what you're doing. Leave it in as short as possible a gear until you hit redline, then constantly gear it down so that you make peak hp until you reach your desired goal. Acceleration doesn't get any more ideal than that.
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Old 11-13-2001, 09:43 AM   #38
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Once you learn how a CVT works (not in theory...but by using it), you can actually do things like that. Some cars even have "gear" that you can place CVTs in...just like if you were shifting. I think it kinda defeats the purpose of the CVT, but somebody must like that.

I'm a "row-your-own" kinda person. But the current crop of CVTs aren't performance transmissions. When they get up to that range, you'll see that you don't need a shift lever to do what you want.
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Old 04-08-2005, 01:59 PM   #39
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cvt trans

think about the way a snowmobile work's.it is the same way with out all the parts...
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Old 04-08-2005, 04:24 PM   #40
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Re: continuously variable transmission

HOLY POST REVIVAL BATMAN!!


Quote:
Originally Posted by IntegraR0064
Well.....that'd be a good idea, but they still can't do it, since they don't have stuff that can spin at 15k rpm constantly.

Anyway I'd be willing to bet if it can't handle torque very well, it wouldn't be able to handle high horsepower levels very well either...its probably just not as big of a problem. I don't know though, I haven't really looked into cvts in too much detail yet.

Either way though...
With the wisdom that the last 4 years have given me since this post...I can say I was a complete moron. Of course it wouldn't be able to handle high horsepower...we're talking about a transmission. The transmission makes no distinction between horsepower and torque..they're all the same to it. So no matter how you're making engine faster, the CVT (of those times) wouldn't be able to handle it.

So that whole discussion was pointless.
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