Sunday, September 12, 2010

Inductive Highway

Electrical cars would be great. Low maintenance. Cheap to power. Super efficient. Extremely quiet. (Unless you want it to be loud, in which case we can make it sound like a well-tuned sports car.) Just one problem: With existing technology, you have a range of at most 50 miles before you need to recharge it. That's not enough in America, where our petroleum-powered cars go 200-300 miles on one tank of gas. (Depending on the efficiency of the car, and the size of the tank. A police cruiser getting 8 miles to the gallon just isn't going to go as far as a small hybrid that gets 60 miles to the gallon.) And where to charge it on the road? The American owner of an electric car probably can't find anywhere to charge it other than his or her own house.
But: All car journeys in America are either short trips around the city for errands, in which case 50 miles isn't that restrictive a limit, or trips to another city, which involve long freeways that are restricted only to cars. Pedestrians may not set foot on a freeway, as it is simply too dangerous. (Freeway speeds vary from 45 - 85 MPH, with the higher speeds being the more remote highways.) And with these two factors, I came up with a way that the freeway itself could power the car.
Electrical engineers have long had a technique to transfer electricity to things that are nearby, but not quite touching: Inductive current. So we would make the entire highway have inductive-current lines down the middle of each lane. Driving the electrical car down the freeway would charge it up, and use this electricity to go faster still. And at the driver's destination, they still have full batteries.
The devil of how to pay for this rears its ugly head, though. People are going to want a free ride, but the operators of electrical plants understandably want to be paid. I suppose while we're using non-contact technologies, Radio Frequency Identification, or RFID, can come to the rescue. The driver would have an RFID tag on the bottom of their electrical car, which would indicate an account, and if it was valid, then that section of road gets inductive current turned on, and at the end of the month, the account gets a bill. You're charged per distance of road, which pumped a set amount of electricity into your electric car. This is fair.
The two things I wanted to avoid was accidental contact with pedestrians, which is why I wouldn't put it in ALL sections of road. Basically, the centers of road lanes could at any time become "third rails" (a railroad-based induction charge system), which has killed people in the past. (They touch it, or get very drunk and pee on it, and wind up electrocuted.) I'd also want to make sure this would be safe for gasoline-cars, which show no sign of going away, and even if they were, there would be a long transition period while they were still on the road. If the road set a driver's gas tank on fire, that would be bad.


Alex Waller said...

Inverse Square Law basically makes this tech impossible, unless you want glowing hot conduit running thousands of amps...
Inductive charging works best over a distance of millimeters, not meters. You'd have to have the cars very, very close to the ground (Koreans say 12 cm or less) in order for them to achieve an appreciable charge. Or better yet, invent ambient temperature superconductive wires that can carry the current you'd need for this system to actually work.

Mad Engineering said...

The bottom of the car is maybe six inches from the surface of the road.

....okay, I'll add the "Wrong" and "Stupid" tags.

The Chinese guy said...

This has uses. I was thinking of a similar usage myself. In Hong Kong the air quality is crap, even though the cars use LPG.

Anyway lots of taxi drivers flout the law keeping their engines (and thus their air conditioners on) when they park up at a taxi rank.

Big solenoids could be embedded into the taxiranks easy because HK does not use asphalt roads they use concrete slabs which are lifted in and out of place when sewerage or telephone lines or gas lines need to be installed. And as such electricity could be transfered to the cars to run the air con systems. Since HK electricity is 76% nuclear power generated it should be better for the environment.

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