Jalopnik 
Enter your username and password.
Detroit, 10:17 AM
Fri Dec 11
25 posts in the last 24 hours
Tip your editors:
Editor-in-Chief:
Ray Wert | | AIM
Road Test Editor:
Wes Siler |
Weekend Editor:
Murilee Martin |
Associate Editor - Houston:
Associate Editor - Detroit:
Editor-at-Large:
Contributors:
John Krewson |
Original material is licensed under a Creative Commons License permitting non-commercial sharing with attribution.
10/09/09
Now I'm not sure how GM is going to use this advantage, but being that it is only running to charge the batteries, you could benefit by only running the engine at its most efficient operating conditions (Wide open throttle, peak torque, etc.), unlike a normal engine which has to run over its entire range of operating conditions, with most of them way below peak efficiency.
10/10/09
But that's not what Ben said and that's not how the Volt works. Ben wrote "It doesn't make sense to charge the batteries and drive the wheels." When the Volt's battery pack runs down to ~50% state of charge, the engine runs to generate electricity to power the motor to turn the wheels. Volt chief engineer Andrew Farah says "We’re going to tune the system to operate efficiently at a few points" and they can route any electricity generated beyond the instantanteous demand of the motor to the batteries, but the Volt is not trying to return the batteries to full charge. Should the batteries get to 80+%, maybe because you slammed on the brakes or drove downhill for a while, then the engine will turn off and the batteries will take over again.
Take all of this with a grain of salt since NO ONE outside of GM has driven a Volt with a depleted battery pack, but gm-volt.com is reporting the engineers' latest thinking.
You want to recharge a battery at home where electricity is cheapest - otherwise we'd all run gasoline generators to power our homes!
10/09/09
10/09/09
GM wants to get you where you're going with the cheapest energy source available. For the first 40 miles, that's electricity, for the rest of the available range, that's gasoline. It doesn't make sense to charge the batteries and drive the wheels. Drive the wheels with the e-motors, keep it simple without some complex engine decoupling mechanism.
When you get home, plug in the car and juice the batteries with cheap electricity instead of filling them up with expensive gasoline generated electricity.
10/10/09
10/09/09