GM plans to launch the Chevrolet Volt in 2010. The Volt runs on battery power for the first 40 miles or so, and after that a small gas engine will cycle on as needed to recharge the batteries. Plug-in versions of parallel hybrids, where the engine can directly power the wheel, are also coming.
Earlier today I learned of an interesting discussion at Volt forum gm-volt.com. At issue: how should the Volt’s EPA ratings be calculated. After all, some owners will rarely if every use any gas.
GM wants to simply run the Volt through the standard EPA cycle, which would yield a number over 100. The EPA wants to assume that the gas engine must be used to recharge the battery at the end of the trip, and have it do so. Reportedly, this would yield a 48 MPG figure.
For obvious reasons, GM is fighting for the method that yields the higher number.
Neither party is necessarily correct. If in the real world someone could plug the car in at the end of the trip, they would, and no gas would be used to recharge the battery. If they had to keep driving after the battery was depleted, then the gas engine would have to recharge the battery.
So, it’s really a question of trip length, and how often and for how long the gas engine comes on after the battery is depleted to its low mark (about a 30 percent charge, to preserve battery life).
To me, it seems a bit silly to force the Volt into the regular EPA system. What is really needed are three sets of city/highway numbers.
The first would represent efficiency and range prior to the initial depletion of the battery. The test would have to include two short cycles of just a few miles, one for city and one for highway, to be repeated until the battery reaches its low mark. The standard EPA cycles might or might not work for this purpose, depending on how gameable they are by tweaking battery size and how often and for how long the gas engine runs. The calculation would them divide the number of miles driven by the number of kilowatt-hours used, to get a miles-per-kwh figure.
This is the first pair of numbers. The second pair would report the distance the vehicle could be driven in electric-only mode.
The second test would start with the battery at its low mark and run over the regular EPA cycles. This would yield a third set of EPA numbers.
With plug-in parallel hybrids, the first set of numbers would also have to include MPG figures, for the amount of gas used prior to battery depletion. So, essentially a fourth set of numbers.
Complicated, yes, but it’s not possible to simplify these figures further without oversimplifying them.
The Volt and other plug-ins also pose a challenge for TrueDelta’s Fuel Economy Survey. Clearly a different survey will be required for these vehicles to usefully report their energy efficiency.
Anyone know where you can find more pictures of the Chevy Volt.
Has anything been leaked?
Of course this is just my opinion and speculation but I’d say nothing has been leaked because it doesn’t REALLY exist.
What exists is a wholy normal experimental electric car that isn’t going to be anything like any real car that chevy produces they can make all the claims they want about it just like every other concept car they push out saying it weighs 2000lbs has 500hp and gets 35mpg, (those being the magic specs of another concept car once lauded that never saw the light of day, who can guess which one?) but what the press gets to drive around to make buzz weighs 6000lbs and has a stock powertrain from something else in it and the press goes “wow you sure can feel the power!” but it’s just gearing or in the volt’s case a big ass heavy motor that costs a bundle.
and when we we do see the “volt” expect it to be slow, heavy and very expensive, just like everything else that sees light. If people aren’t willing to downsize the car, electric cars are not going to happen without some serious advancement in batteries which is exactly what GM has been counting on the last two times they cried poor to congress to get money to develop electric cars. The whole Volt program is a farce.
On the subject of spyphotos, check http://www.jalopnik.com or http://www.autoblog.com and search for the Volt. A few have been leaked or caught, and both sites have all of them I think.
I think GM’s right on this one, to a point. They have the right to expect that any vehicle they develop will be subject to current regs. Of course the Volt is different and there ought to be a means to measure the energy consumed, but in the absence of any such tailored standard, the current testing ought to apply.
We had the same problem with the Prius and Insight with the old standard, didn’t we? Their mileage numbers were artificially high because they were designed to the EPA test (as all cars are to a point – case in point the 1-4 skip shift in the Corvette).
The key here is to measure and report the energy used, in something approximating ‘normal’ or ‘average’ use in a simple and straightforward way. That becomes increasingly challenging as we get various types of hybrids, CNG cars, E85 cars and fuel cell cars. The challenge is how to make a single, simple standard that allows cars to be compared.
Perhaps an ‘energy used’ standard for the EPA test would be appropriate. If a Volt uses so many kilowatts, isn’t a fairly simple conversion to say that’s the equal of a certain number of gallons of gasoline or E85 or CNG? Then each car would have an ‘energy used’ rating based on it’s fuel source and a chart listing the energy equivalent in other forms.
An ‘energy used’ standard bypasses the whole ‘how am I going to refill’ question for cars, liek the Volt or even E85/gas cars, that can be refilled in different ways. Not perfect, but a single standard is important because having 4 different numbers is going to make folks scratch their heads and most won’t be able to follow or figure out what they mean.
Problem is, different energy sources have different prices per BTU. I’m gathering that powering a Volt using electricity will be MUCH cheaper per mile than using gasoline. I’d always figured that losses in transmission would cancel out much of the savings of producing energy in volume at a central location. Apparently not.
And this is key, because people don’t care about how many BTUs they use so much as how much it costs them.
The current EPA standard doesn’t take costs into account either, just distance per unit of energy. Gas prices can vary widely from region to region, so it makes sense that they don’t. All energy prices will do that.
Perhaps some general info on relative costs per BTU should be included too, but it gets pretty complicated to maintain pretty quickly. Take a look at gas vs. diesel. A few years ago, diesel was cheaper, now it’s reversed.
There is going to need to be a system that can give folks an idea on how much it’s going to cost to run one car vs. another. With multiple energy sources coming on line, that’s going to be harder and harder.