> Chuck Pliske wrote:
>
> > I've not seen on the list before an important caution being expressed
> > by other folks that have added batteries to achieve longer EV runs:
> > that of oil pressure. There is much anecdotal evidence that the only
> > oil pressure available in the system is achieved by a turning ICE.
> > This implies that long EV drives may need to supply oil pressure in a
> > different way than by forcing the ICE to turn. Toyota effectively
> > finessed this issue by providing EV range of only a mile or so, but
> > longer runs could be risky to the PSD!
> >
> > Chuck

Thanks for bringing up this issue, as, indeed, it hasn't been
discussed before in this group. I was one of the posters discussing
it in, I believe, Prius_Technical_Stuff, though. Also, it is alluded
to in our Strawman Specs, and has been on our minds.

--- In priusplus@yahoogroups.com, "Tom Stangl, VFAQman" <talonts@v...>
wrote:
> Yes, evidently there are specific points in the PSD where splash oiling
> is not enough. Why Toyota built the system this way, I don't know. An
> electric pump, or a simple gerotor driven off of the PSD itself, that
> would be pumping oil no matter what motor was spinning, would have
taken
> care of it. Then again, it really isn't needed with the short EV range
> of the OEM battery pack.
>
> I see 3 basic ways to produce the oil pressure:
> 1 - fire up the ICE every once in a while. Defeats the purpose of EV
> 2 - spin up the ICE every once in a while. Will shorten EV range.
> 3 - build an external oil pump system activate when in EV mode.

These do appear to be our options, but I don't see them as much of a
problem. #1 is likely to occur anyway, as the currently available
EV-only mode only works up to 35 mph and moderate accelerations. We
just need to ensure that it occurs often enough. In most cases it
shouldn't significantly affect the value one gets from plugging in, as
EV propulsion need not be pure as long as one drives far enough each
day to use up the energy in the traction battery.

My guess is that #2 would shorten EV range by significantly less than 1%.

Unless further input convinces us otherwise, I would expect in the
short run to drive so that the ICE starts every so often, then later
put some software in the EnergyCS controller to check oil pressure if
available and force minimal ICE operation when necessary. If this
proves to be a problem, we can advance to solution #2 or #3.

/ron