Re: Jetta Hybrid Conert?

["VanDerWal, Peter" <vanderwp@fhu.disa.mil>]

> Why would you need a transmission on the rear electric drive? If the
> final output from a transmission is 1:1 to the drive shaft, 

Ah, but you misunderstood that post.  It's 1:1 ratio from the wheel to the
Engine, not the drive shaft.  The drive shaft typically runs about 3-4 times
as fast as the wheels (my fault earlier, I had it reversed).

>why not just
> drive direct to the rear differential and use the ICE for acceleration
> boost and base-lever cruise power? In theory on the straight and level
> you could drive all electric. 

A 4:1 reduction from drive shaft to wheels isn't really enough for most
electric motors.  This would only have the motor spinning at about 3500 rpm
when going 60 mph (loafing).  At lower speeds it's even worse.
Assuming you wanted an absolute top speed of 75mph and your motor redlined
at 6500, you'd want a 5:75 to 1 rear differential.  Such a beast might be
available, I don't know.

If you wanted a lower max speed or had a motor with a higher max rpm, you'd
need an even higher ratio rear end.