garygid
04-19-2008, 09:21 AM
The Insight's tire goes a little over 900 revolutions per mile.
At 60 mph (one mile a minute), that is 900 revolutions
per minute (rpm).
Guessing that the belt drive "gearing" (rpm reduction)
is between 2:1 and 3:1 per stage, the two-stage ratio
would be somewhere between a 4:1 and a 9:1 ratio.
For an approximation, something like 6 or 7 to one
is quite possible, so I will choose 6 for this calculation.
Wheel 900 rpm, motor 900 x 6 = 5400 rpm, at 60 mph.
This is 90 rpm on the electric motor for each mile-per-hour.
Then at 85 miles per hour, 5400 x 85 / 60 = 90 x 85, or
around 7650 rpm for the electric motor at 85 mph.
I suspect that this "top end" rpm estimate is a little low.
The "top end" electric motor rpm would be higher if the actual
"gear" ratio is higher then 6, and lower if the ratio is lower.
Again, just guesses and speculation.
It will be interesting to see the real drive train specs.
At 60 mph (one mile a minute), that is 900 revolutions
per minute (rpm).
Guessing that the belt drive "gearing" (rpm reduction)
is between 2:1 and 3:1 per stage, the two-stage ratio
would be somewhere between a 4:1 and a 9:1 ratio.
For an approximation, something like 6 or 7 to one
is quite possible, so I will choose 6 for this calculation.
Wheel 900 rpm, motor 900 x 6 = 5400 rpm, at 60 mph.
This is 90 rpm on the electric motor for each mile-per-hour.
Then at 85 miles per hour, 5400 x 85 / 60 = 90 x 85, or
around 7650 rpm for the electric motor at 85 mph.
I suspect that this "top end" rpm estimate is a little low.
The "top end" electric motor rpm would be higher if the actual
"gear" ratio is higher then 6, and lower if the ratio is lower.
Again, just guesses and speculation.
It will be interesting to see the real drive train specs.