As I reported earlier, I put a CVT belt drive on my Aspire,
a Comet 94C,
http://www.hoffcocomet.com/comet/aftermarket-torque-converters.asp#94c
It has a variable gearing from 3.49:1 to .78:1. When I connected it
directly to the rear wheel in the aspire, it didn't have enough torque
to get the car moving from a stop, the belt just slipped. No surprise
really, it would have been nice if it worked, so I gave it a try.
To fix it, I built a 3.27:1 planetary gear setup for the driven pulley,
http://www.nimblemotorsports.com/planetary.jpg
This weighs only 32lbs.
So now the car starts off with a 12.9:1 gear and a seamless transition
to a 2.55:1 gearing.
I took it for a test drive today, and it works great, no problem at all
from a start.
If my calculations are correct, the motor at 5000 rpm could transition
from 27mph to 140mph through the gear ratio.
I don't have a tach on the motor yet, but the calcs show at 25mph the
motor at 2500rpm with the belt drive at mid-point, and that is about
what it looked like today.
A remaining issue is running the car with ICE power. The electric motor
does still spin, the belt mostly slipping, however a couple times it
would get engaged in the motor and spin up to speed, in which case, it
would create momentum to keep the car moving when lifting the ICE
throttle. Not sure if that is a bug or a feature, but it didn't happen
every time. More testing to do, but I'm quite pleased with the results
so far.
Jack
a Comet 94C,
http://www.hoffcocomet.com/comet/aftermarket-torque-converters.asp#94c
It has a variable gearing from 3.49:1 to .78:1. When I connected it
directly to the rear wheel in the aspire, it didn't have enough torque
to get the car moving from a stop, the belt just slipped. No surprise
really, it would have been nice if it worked, so I gave it a try.
To fix it, I built a 3.27:1 planetary gear setup for the driven pulley,
http://www.nimblemotorsports.com/planetary.jpg
This weighs only 32lbs.
So now the car starts off with a 12.9:1 gear and a seamless transition
to a 2.55:1 gearing.
I took it for a test drive today, and it works great, no problem at all
from a start.
If my calculations are correct, the motor at 5000 rpm could transition
from 27mph to 140mph through the gear ratio.
I don't have a tach on the motor yet, but the calcs show at 25mph the
motor at 2500rpm with the belt drive at mid-point, and that is about
what it looked like today.
A remaining issue is running the car with ICE power. The electric motor
does still spin, the belt mostly slipping, however a couple times it
would get engaged in the motor and spin up to speed, in which case, it
would create momentum to keep the car moving when lifting the ICE
throttle. Not sure if that is a bug or a feature, but it didn't happen
every time. More testing to do, but I'm quite pleased with the results
so far.
Jack
