RE: 1-O-X revolutionary digital EV motor)

["Roger Stockton" <rstockton@delta-q.com>]

No, not quite.

It was stated that the EV1 has a much shorter range in stop and go
operation than it does in steady state highway-type operation.  This is
based on observation, so we are accepting it as a fact; it is not what
is being debated.

It was separately suggested that motors such as the EV1 uses for
traction have operation points where the efficiency is single-digit
despite the impressive peak efficiency numbers attained over wide ranges
of operation.  This is also known to be true (e.g. 0% @ 0RPM, rising
smoothly with RPM) and the efficiency maps you pointed us to confirm
this trend (broad high efficiency ranges at medium to high RPM, and
plummeting efficiency at low RPM).  So, this too is not being debated.

It is hypothesised that the sort of range reduction exhibited by the EV1
in stop-and-go operation is at least in part due to the greatly reduced
drivetrain efficiency at very low speeds.  What is debatable is how
great the contribution of reduced drivetrain efficiency is to the
overall observed reduction in range.

It is important not to confuse stop-and-go operation with steady-state
low speed operation; I believe that the energy consumed by repeated
acceleration plays a large role in the observed range reduction,
especially since regen will not be particularly effective at recovering
any of it at such low speeds.  However, an excellent point has also been
made that at very low average speeds the parasitic loads in the EV1
become more significant sources of loss and will also contribute to the
range hit.

Cheers,

Roger.

> -----Original Message-----
> From: owner-ev@listproc.sjsu.edu 
> [mailto:owner-ev@listproc.sjsu.edu] On Behalf Of Victor Tikhonov
> Sent: October 31, 2001 12:34 PM
> To: ev@listproc.sjsu.edu
> Subject: Re: 1-O-X revolutionary digital EV motor)
> 
> 
> It was said that EV1 looses half of the range due to this 
> single digit efficiency with stop-n-go operation. This means 
> half of the range distance (~80 miles) it goes at below 10 
> mph, which is obviously not the case (unless we're talking 
> average speeds in suburban driving, running errands 
> all day long at 25 mph max).
> 
> Victor