I believe the Hybrid Escape uses a drive system very similar, if not identical to the Toyota. I drove an early production Escape & was totally impressed with the transparency of the system. - when it switched between electric & combustion power. Low end power on all electric propulsion was impressive.
Kenneth Waller ----- Original Message ----- From: "Godfrey DiGiorgi" <[EMAIL PROTECTED]> Subject: Re: OT: Toyota hybrid-electric drive system > On Aug 9, 2006, at 11:57 AM, Kenneth Waller wrote: > >>> What would you expect to see in a car of similar age with lower >>> mileage? >> >> I don't know, that's why I posted the question. Maybe someone more >> knowledgeable in battery technology might have a feel for the >> effects of a >> high mileage vehicle's battery condition vs a similarly old vehicle >> with >> relatively low mileage. I'm thinking of the possible effects of many >> charging cycles vs a lot less. > > You should hunt around the rest of John's website ... there are pages > and links to a lot of technical information about the drive system. > > It's pointed out in other technical references to the Synergy Drive > System that the design of the system is prioritized to preserve and > benefit the battery to the greatest extent possible, as well as to > mask aging issues. The control system monitors battery state, > prevents as much as possible high drain as well as low charge > conditions, and balances power generation using the ICE to supply > current for the needs of the drive system as well as other > accessories to accomplish this. > > The drive system is not designed to operate on battery alone: it is a > relatively small capacity battery relative to a full electric car's > design and can power the drive system for only a short period (up to > a mile or so) before being fully depleted. The ICE and power > generation control is essential to operation for anything other than > limited uses. > > As the drive battery ages and capacity/current delivery is > diminished, the control system takes this into account and uses more > power generation using the ICE to compensate for the battery > degradation. A battery with 10,000 charge/recharge cycles on it, even > though it has (theoretically) perhaps only 80% of its original > capacity and current delivery capability, should be capable of > powering the car with very little to no noticeable difference in > operation. The differences would show up ultimately, as the battery > capacity continues to diminish, as increased fuel consumption as the > ICE would be delivering more power generation required for operation > of the electric drive motors. > > Given the sophistication of the control system at masking normal > degradation of the battery over many cycles like this, I suspect that > it would be difficult to see any difference between how John's car > operates with its very high mileage/many cycles battery vs a much > lower mileage example. You'd likely have to do diagnostics on the > battery itself to see much difference, or higher resolution > monitoring of the fuel economy. John provides the available data from > his car on other pages on his site, as do some other users, so > perhaps collating and comparing them would bear this out. > > I imagine that the limit of use is when the battery's capacity and > current delivery drops below the threshold that will run the system > without undue strain on the other components or produces severely > reduced initial acceleration (since the battery and electric drive > motors are the primary power source for starting from rest, the > engine is geared too high to supply adequate torque at starting speeds). > > fun stuff. I'm enjoying learning about this car immensely. Just a few > more days and I'll be driving mine ... then I can tell you from a > practical standpoint of use what I think about it. ;-) > > Godfrey > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
