Chevy Volt Technical Updates From Chief Engineer Andrew Farah

Chevy Volt Technical Updates From Chief Engineer Andrew Farah

By John O'Dell November 29, 2009

Chief Engineer Andrew Farah poses with 2011 Chevrolet Volt at Dodger Stadium media drive.

We have questions, readers have questions - and sometimes disagreements with what we've reported previously. So we took a notebook full of queries to Dodger Stadium this afternoon and asked the guy who ought to know just how things work on the Chevrolet Volt.

This is the word, direct from Volt Chief Engineer Andrew Farah.

1) The battery and battery charging.

• The 16 kilowatt-hour battery has 8 kilowatts of usable energy and generally doesn't deplete below a 30 percent state of charge.
• Charging is accomplished from either a 120-volt or 240-volt line. Both will use the same charging port (right) and connector.
  
• The 110-volt charging cord (below, right) that plugs into any regular outlet is likely to be the "free" charger supplied with the car, the 240-volt charger is likely to be an option and at least a little bit pricier than the 100-volt charging cord.
• It takes roughly 8 hours to charge the battery on 120 volts, 3 to 3.5 hours on 240.
• The battery is never fully recharged by either regenerative braking or the engine-generator once the Volt has gone from charge-depleting, or battery only, mode to charge sustaining, or engine-generator, mode.
  

2) Battery-only range.

• The 2011 Chevrolet Volt will deliver 40 miles of battery-only range on the EPA city cycle, a driving circuit with an average speed of 19.6 mph.
• Aggressive acceleration, sustained high-speed driving, exceptionally hot or cold ambient temperatures, hills, mountains and other such stuff will diminish the Volt's battery-onl range.
• If you pull out of the driveway with a full charge, hop on an uncrowded freeway and motor away at 65 miles an hour, you won't get 40 miles on battery power alone.

3) Engine-generator.

• The 1.4-liter, flex-fuel engine and attached generator kick on when the Volt's battery has approximately 30 percent of its charge remaining. The engine-generator then remains the Volt's principal source of electrical power for the duration of the drive, until the battery is recharged from the grid.
• The engine-generator does not recharge the battery.

• It does, however, divert some of its output to the battery when the state of charge drops below 30 percent, as when accelerating up hill or to pass another car when in charge-sustaining mode. In effect, juice from the engine-generator is used from time to time to bring the battery up to what GM calls "zero balance."

• GM didn't allow us to raise the hood for photos, sorry.
  

4) Total range.

• The Volt's 40 miles of low-speed range in battery-only mode will be augmented by 300 miles of engine-generator range, for a total of up to 340 miles, not 300 miles as has been previously reported.

5)  Transmission, etc.

• The Volt's beefy shifter handle (right) is mounted just below the center stack and provides five options: Park, Reverse, Neutral,  Drive and Low.
• The transmission is a single-speed model, however. Reverse merely reverses the polarity of the electric motor that propels the Volt, while shifting into low sends a signal to the powertrain brain to increase the amount of regenerative braking - a useful tool for gathering juice for the battery while heading down a long mountain grade, or to help reduce use of the brake pedal in stop-and-go traffic.
• Just above and the the left of the shifter handle is a "power" switch that adds almost 30 horsepower to the electric motor's output. It eats into battery range, but give the Volt a bit more oomph.
  

6) Performance.

• Electric motor rated at 150 horsepower, 370 lb.ft. of torque.
• Top speed still listed at 100 mph.
• Acceleration estimated at "under 9 seconds" for 0-60 sprint.
• Cold and heat will impact driving performance, but not excessively.
• Extreme cold and heat for prolonged periods will diminish battery performance, however and might make the Volt a poor choice for some. "If you live in an underground house in Phoenix and have to park the car out in the open up top," is one example Farah provided.
• Volt's performance in ordinary driving situations is no different in battery-only mode than in engine-generator mode.
  

7) Fuel efficiency.

• GM still isn't ready to divulge the specific numbers, but the fuel tank - for either gasoline or E85 ethanol-gasoline blend - is likely to hold somewhere between 8 and 10 gallons, for engine-generator fuel economy of between 30 and 38 mpg (on gasoline, we expect; ethanol reduces fuel efficiency).
• Factor in the gasoline equivalent of battery energy use and the Volt is likely to turn in a combined city-highway EPA number in the range of 80-100 miles per gallon.
  
• As in all fuel economy estimates, real mileage will vary.

Other Edmunds reports on Sunday's dive can be found at Inside Line and Edmunds.com. An Edmunds exclusive video can be viewed here.

John O'Dell, Senior Editor

John O'Dell:  is an AutoObserver Senior Editor. Follow @AutoObserver on Twitter.