See if I have this right. The pavement is magnetized, the vehicle has a coil near the pavement of some sort. As the car moves, this is pushing a coil through a magnetic field, which is the classic generator, and would generate current.
But it will also slow the car, requiring the battery to spend energy keeping it at speed (unless it's downhill). But on downhill portions, the car can do this on its own using regen braking, which in effect is the same process.
What am I missing?
Okay, a few things.
First, let's go back to the bar magnet going into a coil of wire. As you try to push the bar through the coil, the
change in magnetic field will generate a current in the wire, and that current will create a counteracting magnetic field that pushes against the bar's movement.
Now, if the coil is, say, 10" long and the bar magnet is 48" long, here's where it gets interesting... Once the bar magnet is fully inserted in the coil of wire, if you pass the bar magnet through the coil at constant velocity there will be no current generated and no force either way, because at that point the magnetic field is not
changing within the coil. Current comes from the change in the field. Then when you get to the end of the bar magnet, and you're trying to pull it out of the coil, the current in the wire will reverse, the magnetic field will reverse, and the force will reverse, actually trying to hold the bar within the coil and not let it go.
So that's where 94 and I first got on the idea of an alternating magnetic field, rather than constant. Because if the field is constant and the velocity is constant, there will be no change in magnetic field despite the motion, and no current will be generated.
So we'll start with the area in which you're correct. If you basically magnetize the road in longitudinal strips, say every 5 feet is a distinct magnetic north and south, and the receiver coil is set up in the direction of motion, you're correct. The change in magnetic field as you go over the road will generate current in the wire and also generate a magnetic field opposite the direction of travel that will slow the car. The amount of energy generated in the coil should be equal to the magnetic field in a 1:1 relationship, with the amount of energy/force proportional to the speed of the car. The car's motors must then produce an equal amount of energy to counteract the magnetic field generated by the coil. Because you'll have efficiency losses both in the charging electronics and the battery->motor->wheels drivetrain, fundamentally I don't see how you can actually add energy faster than you deplete it, making this a net negative.
HOWEVER, and this is a big one, it is NOT clear that you need to have the magnetic field and the receiver coil oriented in the direction of travel.
If you use either of my examples:
- The field is oriented vertically, with the north or south pole of the magnet pointed towards the sky and the opposite pole pointed towards the center of the earth. The receiver coil is oriented vertically as well. The magnetic field is still alternating every few feet, so you still get a change in magnetic field as you drive over it. But the counter-field generated in the coil results in a force of attraction/repulsion that is oriented vertically. Thus it has no bearing whatsoever on the direction of travel and the car's motors do no extra work.
- The field is oriented horizontally, transverse to the direction of travel. I.e. north is left and south is right, and then every few feet you reverse it. You mount the receiver coil also horizontally transverse to the wheelbase. Now the magnetic forces generated are left/right and again don't impact the amount of work the motors have to do.
In both of those cases, no forces are generated that counteract the forward motion of the car. It's more akin to putting a solar panel on the top of the car--you're taking advantage of something effectively free. Magnetic energy, from the standpoint of the car, is free, much like a coiled wire in the roadway, from the standpoint of the car, is free. With enough energy (whether solar or magnetic or inductive charging in the road) you could even charge the car faster than the motors deplete it, without violating the laws of nature and creating a perpetual motion machine.
The big question, much like putting a solar panel on the roof of an EV, is whether you can create a magnetic field strong enough in the road to make even a measurable difference. That's where I think this project will likely fall flat.