September 5, 2013 – Vol.18 No.25
AN ELECTRIC CAR THAT WON'T BE BUILT.
by Bruce Mulliken, Green Energy News
If there's money in your pocket why not spend it?
The U.S. Department of Energy's Advanced Technology Vehicle Manufacturing (ATVM) loan program is apparently back in business, accepting loan applications. According to Bloomberg News, there's still about 60 percent of the Bush II era program authorized by Congress available to lend, about $15 billion, so why not find some customers, like another start-up electric car company?
The program was heavily criticized when plug-in hybrid car builder Fisker went belly up. But counter to that Tesla Motors spent its loan money wisely, paid it back early, and now is the hottest upstart car company on the planet.
The loan program was approved late in the Bush presidency when the cost of gasoline was pushing into the upper atmosphere, oil supply seemed uncertain and there was an agreement in Washington that alternatives to Middle East oil where needed. Loans from the program were to be used help new companies get up to speed and bring cutting edge vehicle technologies into production.
While it may seem that the advanced vehicle industry (read that today as electrically-driven vehicle industry) is on autopilot and cars will get better and better, while falling in cost, this is really not the case. There's still a long way to go. The vehicles are still too pricey compared with their conventional counterparts, and, in regards to battery-only electric vehicles, range is still stuck at about 80 miles. (Unless of course you can spring 70 grand (and up) for a Tesla Model S)
So there's still plenty of room advancement in advanced vehicles. But where? Where could the loan the money go and for what technology?
Well, there's one thing for certain. I won't be getting any. Though I have some thoughts on some technologies to make advanced vehicles better, the loan program is for those who can demonstrate that they can actually build cars or parts. I have lots of tools in my garage, but somehow I don't think that's quite enough to satisfy the Department.
They also won't lend money based on a hunch, with no solid engineering to back it up.
That said, if I could build an electric car I would do something the no one else seems to have tried. I'd put new focus on the heart of electric vehicles, the drive motor. Instead of trying to make the electric drive motor really light and small and hide it in the chassis somewhere out of site, I'd make it really big and round, but really thin: a pancake motor lying just like it would on a griddle, flat side down.
From everything I've read large diameter electric motors have gobs of torque and that's what you really need to get a car to perform.
A developer of electric scooters driven by large diameter motors says this in its website:
"A large diameter motor has more torque for acceleration and hill climbing than smaller diameter motors at the same amps/volts. This is because the output torque quadruples when the motor diameter is doubled at the minimum."
It makes sense to me that a large diameter motor would have more torque than a skinny one for the same amount of energy pumped into it. After all, an electric motor is a rotating lever and the longer the lever arm, the radius of the motor, the easier, the less energy would needed to spin the motor and anything it's attached to, like a wheel. It's kind of like moving the big rock in the yard. You can either struggle and strain and pick it up by hand, or you can be smart about it and push it out to the way with little effort with a long crow bar. Torque is defined as a twisting force that tends to cause rotation. A long lever like a crow bar easily twists and turns a rock out of the ground. The lever in an electric motor is the distance, its radius, between the air gap and the rotational center of the motor. The longer this is - the diameter of the motor divided by two - the more torque the motor will develop.
So why don't electric vehicle developers use thin but large diameter motors for the torque they develop? Some do. They call them torque motors and they put them in wheels and call them hub motors.
But most use motors that are physically small, but powerful.
You see I think that the electric vehicle industry is focused on compactness and weight cutting in their electric drive designs, trying to squeeze as much motor power as it can in a small space. Likely this is for two reasons. One, they're converting conventional cars into electric drive and are constrained by the space under the hood available. Or two, they're obsessed with compactness which is evident in just about anything technology-wise.
But the industry should be really be focused on two things: Getting cost of vehicles down and extending range, no matter what it takes. Weight is certainly a concern since it effects range. However, small and compact doesn't necessarily mean light in weight and physically large doesn't always mean heavy. Depending what it's constructed of and how it's built, a very wide diameter, but thin, motor could be very light, but it would certainly take up a lot of space in an engine bay.
So I'm thinking that this car I'll never build would have a motor diameter as much as 3 feet, maybe 4. And instead of running at really high speeds, it would galumph along making low RPMs staying nice and cool and efficient. My big slow-moving, flat motor would do the same amount of work (like pushing the car down the road) using less electricity from its battery pack than the physically small, but energetic motors the industry is now using.
Heck, I can't prove any of this. However, I have a hunch that those in the pancake motor business would agree. Maybe they'll apply for a loan.
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