Inlet-Metering Rotary Distributor Pumps Chapter 23

1. Inlet-Metering Rotary Distributor Pumps Chapter 23 DSL 131

2. OBJECTIVES • Identify the main components of an inlet-metering, distributor injection pump. • Describe the operating principles of an opposed-plunger, inlet-metering rotary injection pump. • Explain how fuel is routed, pumped, and metered from the fuel pump to the injector during an inlet-metering, opposed-plunger injection pump cycle. • Outline the circuits in an inlet-metering, opposed-plunger rotary distributor pump.

3. OBJECTIVES (Cont.) • Describe the operating principles of Stanadyne Roosa and Delphi Lucas CAV rotary injection pumps. • Describe how an inlet-metering, opposed plunger, rotary injection pump can be adapted for partial authority electronic control.

4. INTRODUCTION • In the days before electronic engine management systems (ECMs), a significant disadvantage of port-helix metering injection pumps was up-front cost due to its requirement for close tolerance manufacture and a pump/metering element for each cylinder on the engine.

5. INTRODUCTION (Cont.) • Among the advantages offered by rotary distributor injection pumps are: • Lower up-front cost • Simple disassembly and reassembly (for purposes of cleaning) not requiring costly calibration equipment • Hard value phasing of injection pulse not influenced by wear • Balanced cylinder fueling

6. OPPOSED-PLUNGER, INLET-METERING INJECTION PUMPS

7. Fuel Flow

8. DB2 Pumping Element and Rotor

9. INLET-METERING DISTRIBUTOR PUMP CIRCUITS Transfer Pump Circuit Regulator Assembly Circuit Metering Circuit Charging Circuit Discharge Circuit Delivery Valve Circuit

10. INLET-METERING DISTRIBUTOR PUMP CIRCUITS • Fuel Return Circuit • Mechanical Governor • Advance Circuit

11. Roosa Vane-Type Transfer Pump

12. Charging Cycle

13. Discharge Cycle

14. Advance Circuit Componentsand Operating Principle

15. SUMMARY • The inlet-metering, opposed-plunger rotary distributor pump was invented by Vernon Roosa. For this reason, these pumps are often known as Roosa Master pumps. • Inlet-metering, rotary distributor pumps were widely used on older, small-bore diesel engines up until the mid-1990s. • They were manufactured by two companies: Stanadyne in the United States and Delphi Lucas CAV in the United Kingdom.

16. SUMMARY (Cont.) • The main components of an inlet-metering, distributor injection pump are: • Vane pump • Rotor and hydraulic head assembly • Internal cam ring • Opposed plungers • Inlet-metering valve • Governor assembly • Timing advance

17. SUMMARY (Cont.) • An opposed-plunger, inlet-metering injection pump is driven through one full revolution per full cycle on the engine or two complete revolutions. • An opposed-plunger, inlet-metering injection pump has a single pump chamber actuated by a pair of opposed plungers. • Fuel quantity metered into the pump chamber determines the outward travel of the plungers, advancing fuel injection timing in respect of load.

18. SUMMARY (Cont.) • Fuel is moved through the fuel subsystem by a vane-type transfer pump, integral with the pump housing. • This fuel is then routed through the fuel pump circuitry, directed to the metering valve, and from there to the pumping chamber. • Pressure rise to injection pressures is developed in the pump chamber and unloaded to the rotor, from which it is distributed to the injectors.

19. SUMMARY (Cont.) • When adapted for control by electronics, all of the pump’s main circuits remain unchanged. • The ECM controls are limited to control over the advance piston that moves the cam ring and control of the metering valve. For this reason, it is classified as a partial authority system. • Inlet-metering, opposed-plunger pumps were used in some U.S.-built automotive diesels (found mostly in pickup trucks) before the introduction of common rail systems.

20. Any Questions ? • Thank You !