Volt Webchat: What’s the Prospect on Other Battery Technologies?
On Oct. 28, GM hosted a Chevrolet Volt web chat, where participants could ask questions to the following two panelists: Pete Savagian, GM's chief engineer of electric motors, and Lindsay Brooke, an editor with SAE International's magazines group who writes about technologies in the global auto industry, as well as new vehicles, and has covered the Volt's development.
The Volt experienced its best sales in October at more 1,100 vehicle deliveries, according to GM’s Nov. 1 sales report.
Q: Is there any reason traction motors such as used in the Chevy Volt can't be designed to allow being deliberately over-driven momentarily (a few seconds only) to improve 0-60mph and/or 45-85mph times?
Savagian: The Voltec is a fully integrated propulsion system. So speeding up the 0-60 time, or 45-85 mph time you are referencing, would mean not only changes to the motor but also the power electronics, the battery and the controls. Not a simple change.
Q: When I first got my Volt two months ago, it charged to 40 miles. Now it is only charging to 35 miles and saying that it is fully charged. I hear this will happen in the colder months, but why? If it is pulled in shouldn't it always charge to the absolute fullest?? BTW when I first got the car I was using 120-volt charger and now I have a 240-volt charger.
Savagian: The battery is actually charging to "full." However, the range estimation varies based on your driving behavior and your use accessories, such as heating and air conditioning. Monitor your efficiency gauge to improve your battery range performance. The estimator will follow. The range estimator will improve as your actual driving range improves.
Q: Why does Cadillac only have one hybrid vehicle, I know there are plans to give the SRX a system like the Volt, but what about sedans besides the XTS what about the ATS and the CTS?
Brooke: You gotta be patient! GM Powertrain has a portfolio of various hybrid and EV solutions in the works, some of which will be applied to Cadillac future models as appropriate.
Q: What is the estimated operating life of a traction motor such as those used in the Chevy Volt?
Savagian: We validate our electric motors to three lives. Each life is 200k miles of what we would consider a harsh driver, so they are very reliable and durable.
Q: Is GM working on electric motors that do not require rare earth metals and if so, what are the advantages/disadvantages of the alternate technology. Could you explain the difference?
Savagian: We certainly are. In fact, GM has just launched the eAssist program in the Buick Lacrosse that uses an induction motor and has no rare metals. Induction motors work well in high speed and light load applications, like eAssist.
Q: Is it possible to pair a hybrid system with clean diesel?
Brooke: The clean diesel/hybrid pairing is indeed possible. It's most common in the U.S. currently on urban buses (Ann Arbor, MI, is full of them, and the diesels are running on a biodiesel blend). Peugeot is the first automaker (its 3008) to offer this powertrain in production. The challenge is the high cost inherent with diesel engines (reinforced block, cylinders, common rail fuel system, turbos, etc.) combined with the (currently) high cost of batteries on the hybrid side.