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| Illustration 1 | g06083255 |
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(1) Solenoid
(2) O-Ring (3) O-Ring (4) Fuel Supply Inlet (5) O-Ring (6) Fuel Injector Nozzle | |
The common rail fuel system on this engine utilizes electronically controlled fuel injectors. This system uses an electronically actuated solenoid (1) to control the injection of fuel into the combustion chamber.
Pressurized fuel from the accumulator quill tube enters the injector fuel supply inlet (4). Fuel injection occurs when the injector solenoid is energized by the Electronic Control Module (ECM). As the solenoid is energized, a magnetic force is generated. This magnetic force opens an internal control valve which drains the pressure acting on top of the nozzle internal check valve. The pressurized fuel lifts the check allowing high-pressure fuel to be injected into the combustion chamber.
During fuel injection, high-pressure fuel from the accumulator quill tube flows into the injector and to the fuel injector nozzle. Fuel is discharged through orifices in the tip of the injector. The atomized fuel is injected into the combustion chamber.
This fuel injector is cooled by fuel which is routed through the engine cylinder head. Low-pressure cooling fuel enters the injector between O-rings (2) and (3). Low-pressure cooling fuel exits with internal leakage fuel between the bottom O-rings (3) and (5).
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| Illustration 2 | g06428090 |
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Injector Cooling Circuit Fuel Flow | |
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| Illustration 3 | g06040128 |
The tip of the fuel injector (7) protrudes for a short distance below the cylinder head into the combustion chamber as shown in Illustration 3.
This injector also utilizes electronic trim (E-trim) to help reduce injector-to-injector variability at start of life. There is a unique E-trim file that is generated for every injector and is identified using the injector serial number. After the installation of an injector, the corresponding E-Trim file needs to be loaded in the ECM to ensure proper operation of the injector.
High-Pressure Accumulator-Quill
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| Illustration 4 | g06040205 |
The accumulator-quill tube in Illustration 4 transports high-pressure fuel from the high-pressure line, through the cylinder head, to the injector in Illustration 4. The accumulator is held in place into the cylinder head by two stud bolts, nuts and spherical bottom washers. The accumulator-quill tube contains an O-ring which seals low-pressure fuel returning from the injector cooling circuit.
The accumulator-quill tube contains an integral metallic filter to prevent large debris from getting to the injectors. The accumulator-quill tube also contains an integral flow limiting valve. This valve shuts off fuel supply to an injector in the event of excessive fuel delivery into a cylinder. If this action occurs, fuel flow to the cylinder will remain shut off until the engine is shut down. And the fuel rail pressure drops to zero. Refer to Testing and Adjusting, Fuel Rail Pressure Release for instructions on how to release the pressure from the fuel rail.
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| Illustration 5 | g06342387 |
| (8) Threaded diagnostic plug | |
The accumulator quill tube also contains threaded diagnostic plug (8) used in troubleshooting of a high-pressure leak into the double-wall system. Refer to Illustration 5.