Bosch Injector Cut Away Pics
- injectors are not designed to be disassembled and are destroyed when doing so
- the injector's main steel body has a lip that is compressed around the barb assembly to hold it in place (this lip must be ground away to separate.
- the injector's main body also has a lip that is compressed around the needle valve assembly to hold it in place.
- the gasoline path is straight through the center of the injector and is essentially a straw-like structure
- the coil is sealed from the gasoline path with two O rings: one is at the base of the coil assembly and the other at the top of the coil assembly
- the coil assembly is a simple copper wire wrapped on a plastic bobbin with internal magnets
- the energized coil pulls the needle valve up towards the barbed end to open it.
- a spring pushes the needle valve down to close it.
- the coil acts as a simple electromagnet that pulls a non-magnetic metal needle valve assembly that is not affected by applied voltage polarity or current direction
- the resistance of the coil was measured to be 3.2 ohms
- the drawing of the injector in the FSM is 1:1 scale!
Needle valve assembly/case (crimped together), lower O ring, return spring, coil/barb assembly
Disassembled barb assembly showing upper o-ring, plastic coil bobbin, lower o-ring, and copper wire.
Shot of needle valve assembly with number "7" stamped on it. The injector seems to be modular in that a standard casing can have different flowing needle valves crimped to one end and different barbed or O-ring fuel rail fittings crimped to the top. The tip of the needle valve is easily seen as well as the lip of the crimped body..
Look inside case to see top of needle valve assemble, this part moves up and down with needle valve tip.
Another shot of needle valve assembly and bottom of coil assembly
Barb assembly with coil attached.
Coil assembly with O-ring and spring in place.
One for the road
Needle valve assembly removed (note rubber O-ring in place)
Fuel injector body with needle valve assembly removed
4 parts: needle valve, needle valve body & o-ring, C shaped retainer
Looking down the needle valve body