Series 60 Electronic Unit Injector Diagram

The Electronic Unit Injector (EUI) is a lightweight, compact unit that injects diesel fuel directly into the combustion chamber. The amount of fuel injected and the beginning of injection timing is determined by the ECM. The ECM sends a command pulse which activates the injector solenoid. The EUI performs four functions: ‪

  • Creates the high-fuel pressure required for efficient injection.
  • Meters and injects the exact amount of fuel required to handle the load.
  • Atomizes the fuel for mixing with the air in the combustion chamber.
  • Permits continuous fuel flow for component cooling.

Engine combustion is obtained by injecting, under pressure, a small quantity of accurately metered and finely atomized fuel oil into the cylinder. Metering and timing of the fuel is accomplished by the ECM which actuates the solenoid poppet valve to stop the free flow of fuel through the injector. When the solenoid poppet valve closes, fuel is trapped in the injector body and under the plunger. The continuous fuel flow through the injector prevents air pockets in the fuel system and cools those injector parts subjected to high combustion temperatures. ‪

1. Spray Tip ‪ 11. Injector Body ‪
2. Spring Cage ‪ 12. Plunger ‪
3. Check Valve Cage ‪ 13. Upper O-ring Grooves and Seals ‪
4. Spacer ‪ 14. Fuel Outlet Openings ‪
5. Fuel Inlet Opening ‪ 15. Injector Nut ‪
6. Fuel Supply Chamber ‪ 16. Lower O-rings Grooves and Seals ‪
7. Poppet Control Valve ‪ 17. Flat Disk Check Valve ‪
8. Solenoid ‪ 18. Injector Needle Valve Spring ‪
9. Injector Follower ‪ 19. Needle Valve ‪
10. Injector Follower Spring ‪


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