Why CVT's are awesome

[daugen]

Why CVTs Are Awesome Transmissions

this is an educational video explaining the math and physics behind CVT transmissions and why/how they keep
the engine in the power band so effectively. if you like equations, you will like this, but interesting comments on hp and torque.

The funny thing is trans makers often have to build in phony shift points for many models because the public complained of the weird sensations and sounds, probably like listening to a city bus take off.

Hard to explain cvt when folks tend to think it's a giant centrifugal gocart clutch.
I have one on my Kubota UTV with a high and low speed position.
Many smaller foreign cars now have them, great for mpg apparently.

I believe in tractors they are called either CVT or IVT depending upon brands. But with infinite number of speeds, like pushing the cruise control lever ahead in my Kubota, no detents, and the potential for more economical operation, CVT may be a growing trend.
My understanding is that CVT has less parasitic loss than hydrostatic so efficiency is improved.

 

[ArlyA]

Thanks for posting this. Hydrostatic power loss is pretty high and not getting into exact applications, its around 20%. Of course some transmissions are better or worst. Engineering Essentials: Hydrostatic Transmissions | Hydraulics content from Hydraulics & Pneumatics
Where as CVT's loss is in the 2-5% area. Pretty darn good

This is why Hydrostatic transmissions have not been successful is some applications. We won't consider one in a UTV.

 

[LD1]

Bought a nissan with a CVT in 08. I am actually disappointed in how slowly the tech is coming around. CVT's IMO are the best there is. Provided they are designed and programmed correctly. You are ALWAYS in the optimal gear selection for whatever you want to do. Max power. best economy, etc.

Funny how people hate step-pulley mills and drill presses, and prefer variable speeds, but not the same way when it comes to autos. Variable speed (variable pulleys and belts) has been around for decades and decades. In hindsight its hard to believe it has taken this long to adapt into other things, and that the planetary gear automatic transmissions have been so prevalent.

 

[WilliamBos]

Your Kubota UTV uses a hydrostatic transmission, it's NOT a CVT.

The Fendt Vario is the Pioneer example of a CVT, and it's the only clutch less version. All others like JD & CNH use clutch packs.

 

[daugen]

Your Kubota UTV uses a hydrostatic transmission, it's NOT a CVT.

sorry friend, I own the 400 model with the single cylinder Subaru gas engine and a CVT.
The 500 and above models all have hydrostatic.
This thing will grind gears with the best of them if you hurry the shift.

 

[Garandman]

The first car with CVT in the US was the unlamented Subaru Justy. Since then, almost every manufacturer has had a class action lawsuit against them over their initial implementation of CVT.

A local guy just had his 2013 Outback CVT fail (Subaru is one of the few that doesn't have a class action lawsuit - yet, at least). He was quoted $7,000 for a replacement.

 

[Midniteoyl]

Bought a nissan with a CVT in 08. I am actually disappointed in how slowly the tech is coming around. CVT's IMO are the best there is. Provided they are designed and programmed correctly. You are ALWAYS in the optimal gear selection for whatever you want to do. Max power. best economy, etc.

Funny how people hate step-pulley mills and drill presses, and prefer variable speeds, but not the same way when it comes to autos. Variable speed (variable pulleys and belts) has been around for decades and decades. In hindsight its hard to believe it has taken this long to adapt into other things, and that the planetary gear automatic transmissions have been so prevalent.

Because up until recently, CVTs broke.. They did not scale up well with increased weight and HP. I feel they are just now becoming reliable enough to start hitting the mainstream.

 

[KYErik]

I have a 09 Nissan Sentra with CVT. It now has 171K miles on it. My wife and I drove out to Yellowstone and the Grand Canyon over the summer and came back through Colorado- it handled the mountains wonderfully.

I did buy and install a supplemental trans cooler just for extra insurance.

 

[WilliamBos]

Your Kubota UTV uses a hydrostatic transmission, it's NOT a CVT.

sorry friend, I own the 400 model with the single cylinder Subaru gas engine and a CVT.
The 500 and above models all have hydrostatic.
This thing will grind gears with the best of them if you hurry the shift.

Thats a belt drive, not in the same league as the Vario CVT. Yours is no different that what you see on snowmobiles And atv's.

 

[ovrszd]

Thats a belt drive, not in the same league as the Vario CVT. Yours is no different that what you see on snowmobiles And atv's.

That was going to be my question?? In this discussion, when referring to a CVT, you are NOT referring to a dry belt system??

Educated me, I know nothing about a "wet" CVT??