Continuously Variable Transmission

[Frost]

Originally Posted by Lexicon101

I can agree with the bit about each wheel having an engine thing, but how does that remove the power curve?
(I ask merely for information. Not just trying to contest your point.)

Didn't mean to come across as "eliminating the power curve" but eliminating or at least minimizing the tranny. Even electrical motors with instant torque at 0rpm is not really accurate. Technically, it 95-99% torque at very low RPM. There is no such thing as instant in real life.

The best is when I have make an electrician understand that.

[Lexicon101]

Originally Posted by Frost

Didn't mean to come across as "eliminating the power curve" but eliminating or at least minimizing the tranny. Even electrical motors with instant torque at 0rpm is not really accurate. Technically, it 95-99% torque at very low RPM. There is no such thing as instant in real life.

The best is when I have make an electrician understand that.

Ah. Fair enough, but does it continue at high revs? If it has a small range, it doesn't really matter where that range lies, if I'm getting this right. It'd still need a tranny.
If the torque continues up to high revs, then I guess you could just put a ratio usually seen on 6th gear on it, and it'd pull as hard as it can the whole way up, right?

[Frost]

Well the perfect powerplant would be instant 100% power and constant throughout a large range in speed. This way a transmission is not needed and cuts down the inefficiencies. Yes, it could multiply using a ratio via a tranny but if you had the perfect engine why bother sapping out the power of it using a tranny?

Then again, I'm no car engineer... I just love driving them.

[Lexicon101]

Originally Posted by Frost

Well the perfect powerplant would be instant 100% power and constant throughout a large range in speed. This way a transmission is not needed and cuts down the inefficiencies. Yes, it could multiply using a ratio via a tranny but if you had the perfect engine why bother sapping out the power of it using a tranny?

Then again, I'm no car engineer... I just love driving them.

The perfect tranny wouldn't sap power.

[Frost]

Originally Posted by Lexicon101

The perfect tranny wouldn't sap power.

Ah but if you had no tranny, you have no sap!

Imagine a 18" wheel. It will take roughly 2315 revs per minute to achieve a wheel speed of equivalent of 200km/hr (200km/hr = 200,000m/hr = 138,889 revs/hr = 2315 RPM).

Now imagine if that wheel were directly coupled to say something like an electric motor? Now imagine if that motor were say the size of the wheel itself? At that point, sure a tranny might be able to multiply the output but would the weight justify it?

This is where my knowledge ends. I wish there was an automobile engineer who could chime in.

[Lexicon101]

Originally Posted by Frost

Ah but if you had no tranny, you have no sap!

Imagine a 18" wheel. It will take roughly 2315 revs per minute to achieve a wheel speed of equivalent of 200km/hr (200km/hr = 200,000m/hr = 138,889 revs/hr = 2315 RPM).

Now imagine if that wheel were directly coupled to say something like an electric motor? Now imagine if that motor were say the size of the wheel itself? At that point, sure a tranny might be able to multiply the output but would the weight justify it?

This is where my knowledge ends. I wish there was an automobile engineer who could chime in.

18" wheel has a circumference of 18*pi inches = 56.55 inches or 4.7 feet.
One mile is 5280 feet.
An 18" wheel (assuming that includes the tire, as I have been) would need to rotate at 1120 rpms to go 60 mph. (About 100 km/hr right?)
This is well within the range of electric motors, so we move on to power.
The electric engine in a prius generates 44 HP, IIRC. Two, assuming enough power to run both, would output 88 HP.
Tesla's 375 volt motor makes 288 HP and 273 lb/ft of torque. Makes constant torque up to 5000 RPMs and its power peaks where the torque starts to drop off. With 1:1 ratio, 5000 RPMs = 268 mph on an 18" wheel.
I don't know the size of either of these motors, but I'd guess the Prius motor is closer to the size of the wheel. Personally, I'd just put the Tesla motor in the center between both rear wheels, maybe a straight 2:1 gear ratio (Which would put 4480 (engine) RPMs at 120 MPH), or something connected to a drive shaft, connected to the wheel.
Even 88 hp though, combined with the low CoG from having batteries in the floorboards, it probably wouldn't be hard to make it lighter than a conventional car, but don't quote me on that.

[OldSkoolToys]

Originally Posted by Lexicon101

I was wondering who would be the first.
I take it you prefer carbureted engines too, eh?

Whats wrong with Carbureted engines?

[OldSkoolToys]

Originally Posted by Lexicon101

Which is why I said "the idea of" a wankel. Theoretically, very reliable engines.. unfortunately, the application does not always live up to theory.

Early Mazda wankels had their share of problems, but much of the Apex issue can be resolved using FD seals.

On a sidenote, the dark myth behind wankels being impossible to work on is completely bullshit. It is by far the simplest engine I've ever had the pleasure of helping tear apart and rebuild. I mean its REALLY simple. So even if it does go out, you can (with some practice), remove, tear down, and rebuild a wankel within a day. Getting everything setup properly again can be a hassle, the but the actual tear down and rebuild? Stupid easy.

[Lexicon101]

Originally Posted by OldSkoolToys

Whats wrong with Carbureted engines?

What's wrong with horse-drawn carts?
Srsly. We should have stopped developing new technologies ages ago.

[OldSkoolToys]

Originally Posted by Lexicon101

What's wrong with horse-drawn carts?
Srsly. We should have stopped developing new technologies ages ago.

Cleaning up the poop and maintenance.

But you missed the point. There's nothing wrong with liking Carbureted engines. Yes, FI brings more pro's, but mechanically there's nothing wrong with driving a Carb'd car. If anything, its simplicity is its greatest asset.

Would I carb the AE86? Nah. Would I swap an EFI engine into a 240zx? Hell no.

[Lexicon101]

Originally Posted by OldSkoolToys

Cleaning up the poop and maintenance.

But you missed the point. There's nothing wrong with liking Carbureted engines. Yes, FI brings more pro's, but mechanically there's nothing wrong with driving a Carb'd car. If anything, its simplicity is its greatest asset.

Would I carb the AE86? Nah. Would I swap an EFI engine into a 240zx? Hell no.

Someone's gotta clean up the junk and maintain every vehicle ever made. Just because you don't see it doesn't mean your car makes no waste.

... but that's beside the point. I didn't say there was anything wrong with liking carb'd engines. I was just saying, if you were designing a motor today (assuming you had the knowledge required already), you probably wouldn't put a carb on it.

[OldSkoolToys]

Originally Posted by Lexicon101

Someone's gotta clean up the junk and maintain every vehicle ever made. Just because you don't see it doesn't mean your car makes no waste.

Well I'd rather change oil than clean up horse shit. Smells better.

Though I'd probably rather clean up horse shit than change diff / tranny oil. Horse shit smells better.

[Lexicon101]

Originally Posted by OldSkoolToys

Well I'd rather change oil than clean up horse shit. Smells better.

Though I'd probably rather clean up horse shit than change diff / tranny oil. Horse shit smells better.

Fair enough. I have to change the ATF in my civic soon. Not looking forward to it.

[Random_Art]

Ah, but you can't fertilize your veggie garden with used oil!

back on topic- Transmission oil is pretty rank. I'm not looking forward to changing the tranny oil in my Celica. Not because it's rank, but because I practically have to contort my body in order to accomplish the task.