Tuesday, September 16, 2008

GM Unveils Production Version of the Volt

General Motors marked its centenary today by unveiling the much-anticipated production version of the Chevrolet Volt extended range electric vehicle.

The Volt uses electricity to move the wheels at all times and speeds. For trips up to 40 miles (under the EPA city cycle), the Volt is powered only by electricity stored in its 16-kWh, lithium-ion battery. GM uses half of the capacity (8 kWh) in its operating strategy for the Volt. When the battery’s energy is depleted, a 1.4-liter, naturally aspirated gasoline/E85-powered engine range extender kicks in.

The Chevrolet Volt can be plugged either into a standard household 120v outlet or use 240v for charging. The vehicle’s intelligent charging technology enables the Volt’s battery to be charged in less than three hours on a 240v outlet or about eight hours on a 120v outlet. Charge times are reduced if the battery has not been fully depleted. GM estimates the cost of a daily 8 kWh recharge to be about $0.80 (10 cents per kWh).

The Volt’s electric drive unit delivers the equivalent of 150 hp (111 kW), with 370 Nm (273 lb-ft) of instant torque, and a top speed of 100 miles per hour.

GM estimates that the Volt will cost about two cents per mile to drive while under battery power compared to 12 cents per mile using gasoline priced at $3.60 per gallon. For an average driver who drives 40 miles per day (or 15,000 miles per year), this amounts to a cost savings of $1,500 annually. Using peak electric rates, GM estimates that an electrically driven mile in a Chevy Volt will be about one-sixth of the cost of a conventional gasoline-powered vehicle. The cost savings are even greater when charging during off-peak hours, when electric rates are cheaper.
The body of the car changed quite a bit, from this in concept to this now.

Looks like this electric motor goes .2kWh a mile (8 kWh for 40 miles) the same as a Tesla. At $.12 a mile and $3.60 a gallon that would give it a fuel efficiency of 30 mpg. That seems a bit low given its aerodynamics and compared to the 40mpg+ of a Prius.

This vehicle is completely driven by the electric motor, so the engine is just a generator used to convert gasoline into electricity. At 30mpg and .2kWh a mile this means each gallon of gasoline is producing 6 kWh of electricity. Since a gallon has 33 kWh of energy in it, this makes the engine just 18% (6/33) efficient in converting gasoline to electricity. That seems low to me, but I'm not sure what to compare it to.

No word on price but probably somewhere in the $40,000 range (or maybe $46,000). Hopefully we will see these on the road in 2010.

Update: GM Volt Blog reports that the engine will get 50 mpg, which would put the efficiency of conversion at 10 kWh/33 kWh = 33%.

Update 2:Wired reports that the Volt has a 53-kilowatt generator and a 111-kilowatt electric motor. I wonder if you are on a long drive and the battery gets depleted if the engine then loses a lot of its power as the generator can't keep up with the demands of the motor.

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