The 22378579 MP8/D13 Diesel Fuel Injector for Mack and Volvo engines is a solenoid-controlled, electronically actuated unit injector designed for high-pressure direct injection. Here are its key structural characteristics:

1. Housing & Body

• Robust metal construction (typically hardened steel or alloy) to withstand high-pressure fuel and engine heat.
• Compact cylindrical design for integration into the engine’s cylinder head.

2. Nozzle & Tip

• Multi-hole nozzle (usually 6-8 precision-drilled orifices) for fine fuel atomization.
• Heat-resistant needle valve ensures precise opening/closing under extreme temperatures.

3. Solenoid Actuator

• Electromagnetic solenoid controls fuel injection timing and duration via ECU signals.
• High-tension electrical connector for reliable signal transmission.

4. Internal Components

• Pressure intensifier piston (in some models) to amplify fuel pressure (up to 30,000+ psi).
• Check valve & spill port for fuel return and pressure regulation.

5. Sealing & Mounting

• Copper or composite sealing washer at the base for a tight cylinder head seal.
• O-rings & gaskets to prevent fuel and combustion gas leaks.

6. Fuel Inlet/Return Ports

• High-pressure fuel inlet (connected to the common rail or pump).
• Leak-off return port for excess fuel recirculation.