Dual Actuator EUI Systems (Extract) Chapter 26

1. Dual Actuator EUI Systems (Extract)Chapter 26 DSL 131

2. OBJECTIVES • Describe the system layout and the primary components in a full authority, dual actuator EUI-fueled, engine management system. • Outline the role that the four primary subsystems play in managing a dual actuator EUI-fueled engine. • Describe the operating principles of a four-terminal (dual-actuator) Delphi EUI. • Sequence the injection phases of a Delphi E3 injector. • Describe how the ECM manages duty cycle in dual actuator EUIs to control engine fueling.

3. INTRODUCTION • The dominant fuel system of commercial truck diesel engines was the single actuator electronic unit injector (EUIs) system, but by 2007, more precise management of combustion was required.

4. SYSTEM OVERVIEW • Mechanically-actuated, dual actuator EUIs have an effective pumping stroke managed and switched by the electronic control module (ECM) or electronic engine control unit (EECU). • They also control the nozzle opening pressure with a second solenoid assembly.

5. Fuel Subsystem on a Mack Trucks EUI-Fueled Engine • Supply pump (external gear type) • Fuel tank • EECU • Fuel filter housing pad • Pre-filter • Primary fuel filter and water separator (under suction) • Secondary filter • Fuel gallery • Electronic unit injectors (EUIs) • Charging pressure control valve • Safety check valve • Non-return valve • Hand primer pump • Water-in-fuel (WIF) sensor • Dash-mounted water drain switch • Water separator drain valve

6. Fuel Subsystem on a Mack Trucks EUI-Fueled Engine (Cont.) • Bleeder valve • Charging pressure test measuring point • Fuel pressure sensor • Optional fuel heater

7. Fuel Subsystem on a Mack Trucks EUI-Fueled Engine (Cont.) • Valve peg (lock-off for servicing) • Non-return valve • Bleeding valve • Breather vent • Fuel return pipe

8. OUTPUT CIRCUIT • Output circuit devices affect the results of the computer processing cycle into action. • In an EUI fuel system, the primary engine outputs are the EUIs and commands to the exhaust aftertreatment hardware.

9. E3 EUI Nomenclature • The internal components of the dual actuator EUI are similar to the single actuator EUI. • The SV (spill valve) armature performs the same function as the solenoid in a signle actuator by controlling the effective plunger stroke. • A NCV (nozzle control valve) is added to control the NOP of the nozzle assembly. • A higher NOP makes for a better initial spray pattern and a cleaner cut off with smaller fuel droplets.

10. E3 EUI atRest Phase • When both the SV and the NCV are open, all fuel displaced by the plunger is returned to the fuel source.

11. E3 EUIPressurizing Phase • When pressurizing, the SV valve closes causing pressure to build. • Because the NCV is still open, pressure continues to develop, but injection does not occur.

12. Four-Terminal EUI Injection Phase • When both the SV and the NCV are closed, the nozzle is allowed to open, at a more appropriate pressure. • Fuel is now injected.

13. Mack Trucks 2010 MP8 Engine with Cylinder Head Cutaway to Show a Sectioned E3 Injector

14. CAUTION • Failure to reprogram fuel calibration codes when EUIs are replaced will result in the ECM/EECU using fuel flow data of the previous injector programming, which can result in engine fueling balance problems. • In other words, the computer may believe that a new, higher flowing, injector is a low flow unit and allow a longer effective stroke of the plunger causing that cylinder to overfuel.

15. CAUTION • Always observe OEM instructions for draining the fuel manifold when removing EUIs from an engine cylinder head. • When an EUI is removed, the contents of the fuel charging rail end up in the engine cylinder if the cylinder head fuel gallery is not first drained.

16. SUMMARY (Cont.) • It should be noted that the Volvo-Mack common platform engines correlate as 11-liter/700 cu. in., 13-liter/800 cu. in., and 15-liter/1,000 cu. in. They are all metrically engineered and are differentiated primarily by paint job. • Dual actuator EUIs are also known as four-terminal EUIs. They are manufactured by Delphi and described as E3 injectors.

17. SUMMARY (Cont.) • The fuel subsystems supplying E3 injectors regardless of manufacturer use a gear-type transfer pump to create charging pressures. • However, because the fuel subsystem is used by some OEMs to supply aftertreatment dosing injectors, the charging pressures vary from a low of around 60 psi (415 kPa) to a high of 250 psi (1,724 kPa).

18. SUMMARY (Cont.) • ECM functions in Volvo and Mack Trucks E3-fueled engines are divided between two modules—A VCU (MID 144) interacts with the EECU (MID 128) to produce engine powertrain outcomes. • The EECU incorporates both the processing capability and output switching apparatus required to manage fueling and emissions controls on 2007 to 2010 engines.

19. SUMMARY (Cont.) • The control cartridge in an E3 injector is known as a spill valve (SV) actuator. It is an ECM-controlled solenoid and valve that controls effective stroke either by trapping fuel in the EUI or by optioning it to the spill circuit. • The nozzle control valve (NCV) actuator enables the ECM to manage the nozzle opening pressure (NOP) precisely . • The E3 NCV enables soft value NOPs permitting much higher NOP and nozzle closure pressures than would be possible with the hard value NOPs of single actuator EUIs.

20. SUMMARY (Cont.) • The E3 pressurizing phase requires the SV actuator to be energized. • During the pressurizing phase, fuel is not necessarily injected into the engine. • For fuel injection to take place, both the NCV and SV actuators must be energized. • The E3 SV actuator may be energized several times during an injection pulse. This enables multipulse injection.

21. Any Questions ? • Thank You !