Image: Courtesy of Steve Fecht Chevrolet
-
The Best Science Writing Online 2012
Showcasing more than fifty of the most provocative, original, and significant online essays from 2011, The Best Science Writing Online 2012 will change the way...
Read More »
Name: Pamela Fletcher
Title: GM’s Global Chief Engineer for Volt and Plug-In Hybrid Electric Powertrains
Location: Milford Proving Grounds, Michigan
GM developed the Volt in only 29 months. Its lithium-ion battery powers the car for the first 25 to 50 miles, at which point a small gasoline engine kicks in to replenish the battery, allowing the car to travel up to another 300 miles. What were some of your biggest engineering challenges? One was the question of how to integrate the combustion engine with the generator when the car is in its extended-range mode. We wanted the “character” of the car to be as consistent as possible between electric and extended-range operation [when the battery runs down]. To do that, we created a “load-following behavior” for the engine: as power is drawn from the battery, the engine comes in to make up that power. This lets us lead with the battery, and gives the Volt some “EV-ness,” even in range extension.
At the same time, we wanted the engine to respond in a manner that drivers would expect. The Volt’s engine does not have to behave like an engine in a conventional vehicle; its speed does not have to follow the vehicle speed or the throttle directly. So we added some audible cues to assure the driver that the engine “hears” the commands that the driver is giving, such as reducing the speed or load slightly when the driver backs out of the throttle.
Other than having no tailpipe, the Volt looks like many other sedans. Why didn’t GM give the car an edgier design? I have found that people like the fact that this car has a sportiness to it without being overly aggressive. You can be green without driving a spaceship.
The EPA recently classified the Volt as a plug-in hybrid electric vehicle and not as an electric car. What is your reaction to that? Anytime you’re first, those are the kinds of issues that come up. I see the Volt as an electric car with extended range. No kidding—you can have the full performance of the car without the engine ever coming on. These blended plug-ins that are being talked about don’t do that.
What led you to this career path? My dad raced all kinds of cars as a hobby, and I had no brothers. I was the older of two girls, so I was the one who always got corralled into working on the cars and going to the track. After a while, you get addicted to the adrenaline. Not only do you get addicted to the styling, you can also get addicted to the scale and the scope of the industry. I learned to love cars, and I think cars are the greatest consumer product.
This article was originally published with the title Practically Green.
Already a Digital subscriber? Sign-in Now
If your institution has site license access, enter here.
See what we're tweeting about
12 Comments
Add CommentBeing "green" isn't a matter of novel fuel or technology but a genuine reduction in the carbon footprint. That is what Vinod Khosla points out in another article in the same issue. While lithium-ion batteries are relatively non-toxic and recyclable they are not cheap and the electrical energy that charges them probably comes from a fossil fuel burning power plant which turns most of the fuel it consumes into waste heat and carbon by-products. Add electrical transmission line losses and, all else being equal, even battery powered cars aren't all that green. I doubt the Tata Nano will take over American sales, but there is goodness in its approach. I also find it instructive that I owned a 1984 VW Rabbit Diesel that developed only 52 horsepower but consistently delivered 45 mpg in town and 50 mpg on the highway. Our progress over the past 27 years seems modest. In fact, I suspect it is our insatiable desire for features and comfort (air conditioning comes to mind) that makes real progress in "green" vehicles so difficult. The Volt is novel and interesting but it's not a game-changer.
Reply | Report Abuse | Link to thisA good and reasonable assessment, I think.
Reply | Report Abuse | Link to thisSounds like a reasonable assessment, although I'm not sure I agree 100% with the criticism that Electric cars lose the "green" factor because the source of the electric power might be coal/oil. The source could also be solar/wind/hydro/etc... sure it is less likely, but the type of people to own an electric car, are also the type of people most likely to have alternative electric sources like solar.
Reply | Report Abuse | Link to thisI'd say blaming the power supply for being carbon hostile, then blaming the car using that supply as well is a bit like double taxation.
But frankly, until someone can make an electric mini-van with extended range similar to the the Volt, and in a price range not too far above current gas/hybrid mini-vans, electric will just be a fringe tech (although one definitely worth continuing development).
Electric cars are silly. They require massive batteries that have a limited life and are constructed using non-renewable resources. They also have to be disposed of. You need electricity to charge the batteries, so you have an emission free car that hooks up to a coal driven power plant. The tires- there is six gallons of oil in every tire. Electric cars have a limited travel range so you still need 'real' cars for long trips. The whole movement is nothing more than an entertainment. In the end you gain very little advantage at great expense. If we spend the time and energy developing bio fuels we might at least have a new energy source not just be wasting time and money puttering around with old ones.
Reply | Report Abuse | Link to thisI have an 'electric' car too. I disconnected the in-gear sensor on the manual transmission on my Subaru Legacy. I can travel 2-3 feet on the electric starter motor, and the rest of the 325 mile cruising range on the gasoline engine. And all with 2003 technology! Go green! (and all for 1/3 the price of a volt)
Reply | Report Abuse | Link to thisThe most important thing is to get started on the electrical car track. The first innovators and early adopters will show how it can work and make some of the other people a bit more interested. Continously the behavior will start to change. The technology and mass production will do the rest to make a change. Used car batteries will find second use as electrical storage for some years before getting recirculated helping the battery economy as a whole. Combined with GPS, computer aided guidance, faster charging stations, etc will enable people to make a move in a friendly manner. In sunnier places like Malta or Spain people will start using solar cells for charging.
Reply | Report Abuse | Link to thisThe most interesting with Volt is the ability to run a good distance on pure electric. That possibility will pull creativity from their users to find ways to extend that range by a changed behavior.
In July of last year, SA published a two-page graphic that summarized the results of some DOE research into the real carbon footprint of pure electric, plug-in hybrid, and regular hybrid vehicles in different regions of the country (as defined by the sources of electricity in those regions). It is worth looking at. The results range from a significant reduction in carbon in the North West (lots of hydro- and gas, little coal) to significant INCREASES in carbon footprint in the coal-dominant portion of the country.
Reply | Report Abuse | Link to thisWhy did Chevy settle on an ICE engine as opposed to a rankine cycle or brayton cycle engine?
Reply | Report Abuse | Link to thisAlso, why put the ICE engine in the front, it might have made more sense to put it in the rear, and let it simply shaft drive a small rear differential
or even a single wheel.
if you preserve 30% battery, during turns the electric motors can kick in.
Presently trillions of dollars have been invested in the existing auto industry. Auto parts, factories, gas stations, etc. etc.. This obsolete technology will not go away soon.
Reply | Report Abuse | Link to thisElectric cars will likely be withheld (or overpriced -like the Volt and Tesla) from the market to allow for the "gas vehicle conglomeration" to be slowly withdrawn from markets.
American solar companies are already fighting to keep the lower cost Chinese solar panels out of our country. Too many big dollar interests want to keep this cheap form of energy out of the American consumers hands. American utility/energy companies are fighting to make sure they control the "metering" of the sun and wind.
Israel's hatred of the mid-east oil interests & terrorism has prompted them to set up solar recharging for electric vehicles in a big way. They seem to have resolved to other forms of energy, so no more of their oil dollars get into evil hands. Americans should take note of this. We have spent trillions on military funding to the mid east to support control of oil pricing.
Let's compare Chevrolet Volt, $32,780 to Toyota Prius, $23,800.
Reply | Report Abuse | Link to thisDo the calculation:
Volt: 40mpg * 9.3 gallons = 372 miles for gas only
100 miles extra for electric only
Total: 472 miles
Prius: 51mpg * 9.3 gallons = 474.3 miles for both gas + electric but Prius stores actually 11.9 gasoline gallons, range up to 606.9 miles!
Does Volt worth it?
So let's see if I get this right.
Reply | Report Abuse | Link to thisWe use electric cars that can go 30 miles before recharge on NEW batteries, pay $3,500 for replacement batteries and shift all the CO2 to the power companies.
That's about it, right? Oh and we lose 25% efficiency in the process.
Sign me up, bunkie.
It is all a matter of how fast the gasoline prices rise. The more gasoline costs, the better electric cars look. As more generation shifts from fossil fuels, the carbon footprint gets better. Solar is starting to actually become cost competitive due to improvements in efficiency and materials. Never the less, until I can afford to pay cash for an electric car, I'm going to stick with my I.C.E. powered car.
Reply | Report Abuse | Link to this