|
For those electronic "anti-corrosion" modules to work, they would need to be wired to each portion of the car, especially the metal that is far away from the engine bay.
As you know, electricity will take the shortest circuit it can. If the module is wired from your battery to your frame, and because the frame is grounded to the battery, it will take a very short circuit from the location it's bolted to the frame, back into the battery. There may be a very small portion of the engine bay that is protected against corrosion.
On a boat in the ocean... every part of the hull is connected to the anode ( a huge chunk of sacrificial zinc) by the salt water. Big ships will have these zinc anodes at regular intervals along the hull to ensure coverage.
The premise of the module is not to be sacrificial, but to use a small amount of current to reverse the flow of electrons that naturally try to leave the iron (oxidation) and bond with water.
To do the same in a car, we could either submerse the car in salt water, ensuring that all portions of the car form a circuit with the module, or fusion weld many small insulated wires every couple inches to every body panel or chassis component, and run them all back to the 'module'. This isn't practical of course, and if we tried to increase the current, we'd just short out the electronics, and possible cause over-protection, and just cause oxidation of the lead at the other battery terminal (+ve IIRC).
Salt/water/steel will always form a local circuit, which is why galvanizing steel is the only way to protect it, in an air environment. Galvanizing is a sacrificial zing layer, than can help protect steel for many years, even if the galvanizing layer is cracked.
|