Previous injector designs used electro-magnetic solenoids to move the injector needle and feed fuel to the combustion chambers. In piezo injectors, a stack of piezo crystals expand when an ...

Earlier injectors used electro-magnetic solenoids to move the injector needles allowing fuel to flow into the combustion chamber. Piezo injectors use a stack of piezo crystal plates that expand ...

A coil of wire, or solenoid, consists of a wire coiled up into a spiral shape. When an electric current flows, the shape of the magnetic field is very similar to the field of a bar magnet.

For example: they can be turned on and off the strength of the magnetic field can be varied These properties make electromagnets useful for picking up scrap iron and steel in scrapyards.