Volt does not recharge its batteries while driving...

[donee]

Hi All,

Edmunds is blowing smoke at us. They apparently are devoid of technical training, and do not realise, even with the battery at 40 percent charge, or whatever the low limit is, it still has 150 HP . Some editors should just not allow some journalists to write about cars!!!!!

Last time I checked, a 150 hp engine weighs about 400 pounds. The battery is hardly a useless piece of stuff to haul around when down to its lower charge limit. Since its the primary source of power in the car!!!! Just like a 400 pound engine.

[donee]

Hi again,

Well, the big problem with cars is partial throttle efficiency. So, when the Volt 1.4 liters is running, its running at an optimum load, for best efficiency, because it can run fast, even though the car is going slow. Then it can turn off.

I tell you what ain't good for efficiency, its taking your traditional automatic transmission car down a 30 mph road. This car will have better fuel economy at 30 mph, battery at low charge state, than almost anything out there.

[SageBrush]

Complete inability to charge the battery from the engine would be an awful design, due to ICE pumping losses at low power demands, and maximum power output of 70 hp at high demands. As much as I cannot stand GM, I just find that scenario really hard to believe, and unless one of our experts says otherwise, not integral to a serial hybrid design. The two-mode hybrids of GM tell us that they have learned to write battery managment software.

I'm more inclined to believe that GM will allow the battery to cycle between say, 5 - 6 kwh in 'depleted mode' much the same way HSD does. Prius owners know that there will be the occasional very long climb where the battery is drained, and passing other cars is out of the question. GM is going to have quite the PR compaign to explain why this is true in their $40,000 wonder-car, too

Actually, the only reason I can think of that the system would not operate this way is battery longevity, or at least GM's inability to test endurance in this mode in the time they have given themselves to push the vehicle out to market

[Celtic Blue]

Originally Posted by donee

Hi All,

Edmunds is blowing smoke at us. They apparently are devoid of technical training, and do not realise, even with the battery at 40 percent charge, or whatever the low limit is, it still has 150 HP . Some editors should just not allow some journalists to write about cars!!!!!

Last time I checked, a 150 hp engine weighs about 400 pounds. The battery is hardly a useless piece of stuff to haul around when down to its lower charge limit. Since its the primary source of power in the car!!!! Just like a 400 pound engine.

No, donee, the smoke is coming from GM. If GM was technically competent they could explain it. So far they've been incapable of doing something that simple, which doesn't bode well for the final product.

I can't blame any writer for gagging on the crap that GM is feeding him/her/us.

[hobbit]

There's no reason a plug-charge depleted Volt couldn't light
its engine, run it at an efficient point, and both push the car
and send a little charge into the battery at the same time. If
the car is steady-state then it isn't using all of the engine's
output capability anyways, so why not load the engine harder
and send that somewhere useful? The system could simply have a
lower target SOC and once that's reached, simply shut down for
a while under light demand and continue running from the battery.
That a> leaves plenty of room for regen, and b> arrives home with
a reasonably low SOC so plug-recharging still gives good benefit.
.
But GM isn't likely to understand this sort of simple logic,
let alone be able to educate its customers on why a system like
that works like it would and how to best utilize it...
.
_H*

[usbseawolf2000]

I think behind the scene, there is a struggle between making the Volt a RE-EV and a PHEV.

I think Bob Lutz does not want to be a liar and want only the gas engine to power the Volt until you get home. In order for it to be an electric car, it can not combine two power sources (gas engine and battery) or else it will be a hybrid.

From the engineering point of view during the charge sustain mode, it would be more efficient to:

1) Buffer the extra ICE power and charge the battery in cases of going downhills, gust of wind, etc...
2) Battery assist the ICE during high power demands, in order to maintain in the sweet RPM spot

However, this will make the Volt a hybrid.... Will engineers triumph or will Mr. Lutz retire with honor? If the history is of any hint, the engineers are fighting an uphill battle.

[SeniorDad]

Thanks for posting this.

I've been racking my brain trying to figure out what GM meant when they released a statement saying that the Volt would have a 400 mile range with a 12 gallon tank. It doesn't take a math genius to figure that that's not really exceptional gas mileage.

You would have to try pretty hard to REDUCE the range of the Prius to 400 miles on 12 gallons!

Quo Vadis, Volt?

[Celtic Blue]

It is interesting that Lutz has said that the Volt will push everything through it's batteries (via e-mail as noted in other thread.) This does not sound efficient. In driving the Prius efficiently we try to avoid charging and discharging the battery except where we must (warm up slow traffic, hills, etc.) Whenever the Volt relies on charging the batteries with its ICE it is going to get hammered compared to the Prius. Those 30 mpg indications on extended range were no accident.

[SageBrush]

I'm under the impression that a trip through the Prius battery carries about a 15% surcharge vs ICE to wheels. Shouldn't a serial hybrid manage close to 40% ICE efficiency just about all the time ? That would imply a Volt ICE to wheels of 34% if the electric drivetrains of the two vehicles are comparable.

[Dozzer]

So does the proposed Volt have a gearbox system.. or is it direct drive via electric motors..

Wheel hub motors ?

I'd imagine that hub motors would be more efficient. With the ice providing the power directly to the motors and not via the battery when it's out of juice.