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Eight 2011 Chevy Volts took the 1200-mile roadtrip.  (Source: Jeffrey Sauger for General Motors)
The Volt is withstanding the rigors of road testing admirably

The first preproduction models of the 2011 Chevy Volt hybrid electric plug-in vehicle were built earlier this year.  Since then, the vehicle has been put through a number of rigorous tests.  Starting yesterday, a fleet of eight Volts launched on the most ambitious test of the vehicle to date: a 1,200 mile road trip.

Chevrolet Volt chief engineer Andrew Farah is among those making the round trip from the Milford Proving Ground through Ohio, Pennsylvania, Maryland, West Virginia, before returning home.  The drive will take a few days and will require approximately 4 tanks of gas.

The drive is dubbed the "65-Percent Drive" according to Autoblog, which in GM-speak means the test drive made when 65 percent of the vehicle's hardware and software is done.  Reportedly, GM is actually about 90 percent done, but is just sticking to its traditional naming.  GM will complete 70, 80, 90 and 100 percent drives in coming months.

One thing GM is still tweaking is how much power from the gas-engine generator to put directly to the electric drive motor, versus using the generator power to charge the batteries.  GM is finding that frequently putting the power directly to the motor improves performance.  However, the generator will still charge the batteries in some cases, as well.

The engine will be run between 1,200 and 4,000 rpm, using factors like speed and power load requirements to decide on the necessary speed.  GM wants to keep the engine between 30 to 100 percent load, as higher loads reduce pumping losses.  GM was tight lipped about fuel economy under the old method (sustained charge) or the new method (variable speed, some power going directly to the electric motor). 

The company did say that the prototypes are getting good mileage -- over 300 miles on a tank of gas -- when operating in generator mode.  This is in addition to the vehicle's 40 mile all-electric range.  Another interesting test will be when GM runs the car's gas engine on E85 ethanol fuel.  The vehicles are FlexFuel designs, so they can enjoy both gas and ethanol.

As to the battery mode, the batteries are performing well and aren't getting too cold or too hot, both conditions which can degrade performance.  The cars aren't yet reaching the 40 mile target on a charge, but GM expects to pass that milestone on the next test, with tweaking.  On the trip, GM is testing vehicles both running on a depleted battery charge, and a full charge.

GM is also looking to fine tune and minimize noise, vibration, and harshness (NVH).  Currently, the gas engine typically won't turn on until the car is moving, at which point the noise will be drowned out by the wind and road noises.  GM, nonetheless, is pleased with the performance, and plans to further reduce NVH by tweaking vehicle parameters that effect the road and wind noise.

Other GM engineers were off testing Volts at Pikes Peak in Colorado.  One key concern is whether the Volt will reach a "tipping point", where the gas engine can't sustain battery charging, and the battery becomes depleted below the typical minimum of 30 percent charge.  Even a strenuous 14-mile trip to the 14,000-foot summit was unable to overwhelm the 100 hp generator, though, so it appears that the "tipping point" will never be reached in real world situations  -- if GM's claims hold true.

A critical test to come will be how the vehicle performs in cold weather.  In cold weather, the Volt starts with the generator running, to help heat up vehicle and jump-start performance.  Battery performance typically suffers incrementally worse degradation, the colder it gets (this is a major argument for ultracapacitors which perform favorably, but are more expensive).



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RE: looks
By Spuke on 10/16/2009 2:40:49 PM , Rating: 3
quote:
The Volt is a compact car that offer neither high performance nor luxury features, so comparing it to BMWs, Cadillacs, and Acuras just isn't comparing apples to apples.
Can you post a link to the final specs of the Volt? I'm interested in seeing them. Thanks.


RE: looks
By mcnabney on 10/16/2009 3:51:48 PM , Rating: 2
http://en.wikipedia.org/wiki/Chevrolet_Volt

The peak output from the motors turning the wheels is 160hp. That doesn't sound like V6 power to me since this car isn't going to be terribly light. Because these are electic motors I imagine that the torque will be good, but I have never driven an electric car before. The Tesla Roadster provides 248hp at the wheels, but that is a much lighter vehicle.


RE: looks
By Keeir on 10/16/2009 7:03:06 PM , Rating: 3
Hrm...

I think your trying to look at one number and come to a conclusion about driving experience from just that one number.

Here's another number
273 lb-ft of torque
http://media.gm.com/servlet/GatewayServlet?target=...

Yow! Thats alot of twist for a family sedan, even one at 3,500 lbs.

As to the Roadster. Somehow, it achieves a sub 4 0-60 time with only ~100 hp/1000 lbs. Most gasoline cars in the same zone require ~130 hp/1000 lbs...

Conclusion- In the Segment of cars that include Prius and Insight, it should be no contest for the Volt. No, its not going to do better than a WRX STi or MazdaSpeed3. However, the Volt should be better than almost all base model compact/midsize cars and power issues shouldn't be a concern for anyone driving a non-performance car today.


"Well, there may be a reason why they call them 'Mac' trucks! Windows machines will not be trucks." -- Microsoft CEO Steve Ballmer














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