layback40 wrote:
You are forgetting Dean/WWD that you are not dealing with a straight ohmic device. Its a coil so you need to consider it as an inductive device & so the current will be determined by that.
Thanks layback40, that's a good reminder.
Coils ARE interesting devices, they can be used to induce voltage and/or current and/or magnetism into another inductive device (transformer) or ferrous metal, they can smooth a desired range of frequencies (choke), can generate an electromagnet force (solenoid/electromagnet), and more. Coils can also be a receiving device in all those same manners.
Motors are made of coils and are also influenced by Electromotive Force (EMF). EMF causes the counteractive current in the motor coils to reduce input current once the magnetic armature is spinning -- by inducing magnetic energy back into the coils (windings). Coils can also make heat, such as in Induction Cooking.
In our circumstance, the coil is being used as an electromagnet to apply force against the fuel pressure in the fuel rail. There are no moving or rotating magnets or magnetic fields immediately near the solenoid so it should not be greatly affected by counter EMF. However, if there is an AC component to the current energizing the solenoid, then the rising and falling magnetic field being generated by the solenoid will have some affect on the current.
Just for fun, take a magnet (off the refrigerator) and drop it down through 3 pipes. A steel pipe, a copper pipe, a PVC pipe. It will act differently in each one. It will immediately click to the side of the steel pipe, it will drop slowly through a copper pipe, it will drop straight through a PVC pipe. The falling magnet causes counter EMF in the copper pipe which slows the fall of the magnet.
Sorry to be a Know-It-All. I've spent 50 years in electronics.
Dean.