Electronic Unit Pump (EUP) Systems Chapter 28

1. Electronic Unit Pump (EUP)SystemsChapter 28 DSL 131

2. OBJECTIVES • Define the acronym EUP. • Explain the differences between full authority EUP and EUI diesel engine management. • Identify the OEMs who have used and are using EUP fuel systems.

3. OBJECTIVES (Cont.) • Outline the EUP fuel system layout. • Describe the principles of operation of the EUP. • Describe how an EUP converts charging pressure fuel to injection pressure values.

4. OBJECTIVES (Cont.) • Identify the similarities between EUP-fueled engines and those using EUI systems. • Explain how the EUP fuel system was adapted to meet 2007 and 2010 emissions standards.

5. INTRODUCTION • Electronic unit pump (EUP) technology was introduced into highway diesel engines by Mack Trucks with its E-Tech engine that debuted in 1997 and the short-livedDetroit Diesel Corporation (DDC) Series 55 engine. • All post-2007 versions of the MBE-4000 and MBE-900 engines use exhaust gas recirculation (EGR) and diesel particulate filters (DPFs).

6. Cutaway View of a Mack E-tech Engine with EUP Fueling

7. SYSTEM OVERVIEW • If you have already studied electronic unit injector systems, you will know much of what there is to know about EUP systems. • In an EUP system, the functions of pumping and control are separated from that of the atomizing function of the nozzle.

8. SYSTEM OVERVIEW (Cont.) • If we begin by outlining the functions of a diesel engine EUI, they can be divided into three subsystems: • Solenoid control • Cam-actuated pumping • Hydraulic injector nozzle (before 2007) or EHI (after 2007)

9. Side View of the E-tech Engine Showing the Location of the ECM and EUPs

10. Schematic of the EUP Fuel System

11. FUEL SUBSYSTEM The fuel subsystem required to fuel the EUPs is fairly standard in that it can be divided into primary and secondary circuits regardless of the original equipment manufacturer (OEM).

12. Fuel Routing in the E-tech Fuel Circuit

13. EUP Fuel Circuit Flow

14. TECH TIP • Do not crank the engine for more than 30 continuous seconds. • Allow 2 minutes between each 30-second cranking cycle.

15. WARNING Applying air pressure to the fuel tank to prime the fuel system can blow out the transfer pump seals and pump fuel into the crankcase, contaminating the engine oil.

16. INPUT CIRCUIT • Bosch EUP-fueled engines are full authority, electronic management systems with comprehensive engine/chassis monitoring and command circuits. • The input circuit components used are similar regardless of engine OEM.

17. Location of V-MAC IIIInput Circuit Components

18. Location of Sensors on the MBE-900 Engine

19. ENGINE CONTROLLERS ANDMANAGEMENT ELECTRONICS • The way in which Mack Trucks, MB, and Paccar electronically manage their EUP systems is similar. • In each case, the chassis and engine management modules can receive and broadcast data over the J1587 and J1939 data backbones.

20. E-Tech ECU

21. ELECTRONIC UNIT PUMPS • The EUPs are flange mounted to the engine cylinder block directly over the engine camshaft. • An EUP roller tappet rides the center lobe of each triple set of cam profiles, one per engine cylinder.

22. Mercedes-Benz Multiplexing Architecture

23. E-Tech Engine Showing the EUPLine Connection to the Hydraulic Injectors

24. Mercedes-Benz EUP-Fueled Engine Showing the Hydraulic Connection Between the EUP and Injector

25. EUP Operating Principle

26. REMOVAL AND INSTALLATIONOF EUPs As with any engine or electronics system procedure, the appropriate OEM technical service literature is required before starting the work.

27. View of the EUP Manifold and Fuel Module on a Paccar MX385 Engine

28. Overhead View of a Paccar EUP-Fueled Engines External Subcomponents

29. When removing EUPs from the engine, the high-pressure pipe should be removed and discarded.

30. EUP External Subcomponents

31. CAUTION • The EUP assembly may be loaded with considerable spring force depending on the position of the actuating cam profile under it. • For this reason, it is essential that the outboard capscrew be backed out no more than ½ inch (13 mm).

32. WARNING Tappet guide pins are factory installed and should not be removed.

33. TECH TIP • The cam profile under the EUP being installed must be on its base circle; that is, in its unactuated position. • Manually bar the engine to ensure that the engine camshaft is correctly positioned. • Using the starter may result in fuel being pushed through the supply gallery and end up in the crankcase, so this should be avoided.

34. WARNING • Some OEMs have issued service bulletins requiring that the high-pressure pipes that connect the EUPs with the injectors be replaced and not reused. • The reason stated is that the seat on the pipe nipple sets (deforms) when it is first torqued to spec. • Check with OEM service literature to identify the correct procedure for either reusing or replacing EUP high-pressure pipes.

35. Sectional View of an EUP

36. TESTING HYDRAULIC INJECTORS • EUP engines use multi-orifii or electrohydraulic injectors. • Make sure that you identify which type you are working with because what you are permitted to do with each type varies.

37. Typical Nozzle Test Bench

38. Key Components on an EHI

39. Left-Side View of a Post-2007MBE- 4000 Engine

40. SUMMARY • The Bosch EUP system may be classified as a full authority electronic management system. • The only post-2010 diesel engine family using EUP fueling is the Paccar MX Series. • The Paccar MX Series uses EUPs in conjunction with EHIs, similar to the MB EUP engines marketed between 2007 and 2010.

41. SUMMARY (Cont.) • EUP-fueled diesel engine series available in the North American market prior to 2007 were the Mack Trucks E-Tech and Mercedes-Benz MBE- 900 and MBE-4000 Series. • EUP engines sold into the North American markets use a two-module management system.

42. SUMMARY (Cont.) • The Mack E-Tech V-MAC III is a two-module system. • The engine controller (ECU) is mounted on a fuel-cooled heat exchanger located on the right side of the engine. • It is multiplexed to the vehicle control module located in the cab under the dash.

43. SUMMARY (Cont.) • The Mercedes-Benz MBE-900 and MBE-4000 engines also use a two-module system, and what Mercedes-Benz calls the modules depends on the generation. • The PLD or ECM (current DDEC) manages fuel and engine management functions, while a multiplexed VCU takes care of command inputs and communications with other on-chassis systems on the J1587 and J1939 data backbones.

44. SUMMARY (Cont.) • The EUPs are supplied with fuel from the fuel subsystem at charging pressure. • Fuel is constantly cycled through the system circuitry and the EUPs, following that it is returned to the tank. • Actual EUP plunger stroke is dictated by cam geometry. Plunger effective stroke is controlled by the engine electronics by switching the EUP solenoids.

45. SUMMARY (Cont.) • The EUP plunger is a simple cylindrical piston with no milled recesses and drillings. • It is spring-loaded to ride the cam profile and reciprocates within the EUP barrel. • A high-pressure pipe connects each EUP unit with either a multi-orifii hydraulic injector or an ECM controlled EHI.

46. SUMMARY (Cont.) • It is important to observe OEM procedure when replacing EUPs. • Fuel should be drained from the charging gallery in the cylinder block or it will spill into the engine oil. • It should be remembered that EUPs can be under considerable tension if the actuating cam profile is at or close to outer base circle during removal.

47. SUMMARY (Cont.) • The injectors used with EUP-fueled engines are connected to the EUPs by a high-pressure pipe and cylinder head connection tube. • Hydraulic injectors are tested similarly to any other types of hydraulic injectors.

48. SUMMARY (Cont.) • At this moment in time, EHIs are not field serviceable: in other words, EHIs should be serviced by a Bosch dealer. • EHI opening and closing events are controlled by the ECM and are not dependent on hydraulic pressure. They are also capable of multipulse injection events that are required to meet post-2007 emissions.

49. Any Questions ? Thank You !