Rotary Fuel Injection Pumps: Bosch VE & Lucas DPC
What is the Point of Speed Progress at the Pumps?
To vary the start of injection depending on the motor speed.
What Does Positive Assimilation Mean in Diesel Fuel Flow?
The fuel flow decreases with increasing speed.
Purpose of Additional Devices for Pumps
To improve engine performance, specifically torque, consumption, and pollution output.
Differences in Feed Injection Regulation: Bosch VE vs Lucas DPC
Bosch VE: Acts on the roller ring via a spring-loaded plunger. When internal resistance exceeds spring resistance, the plunger rotates, advancing injection.
Lucas DPC: Acts on the cam ring via a plunger controlled by two springs. Transfer pressure dictates the cam ring’s position, affecting injection timing.
Developing a Bosch VE Pump on the Engine
Students should learn pump operation and testing procedures. The instructor should demonstrate correct processes and intentionally introduce errors for better understanding. Follow manufacturer instructions for setup.
Advantages of Rotary Pumps over Line Pumps
- Improved accuracy of flow injection per cylinder
- Higher speed and maximum rotation
- Less weight and bulk
- More economical
Key Parts of Bosch VE Rotary Pump
- Feed Pump
- High-Pressure Pump Distributor Element
- Mechanical Speed Regulator
- Stopping Device
- Variable Speed Hydraulic
Role of Pressure Control Valve in Bosch VE
Maintains necessary pressure for specific regimes, returning excess fuel to the pump vane.
Movement of Bosch VE Distributor Piston
Linear, from Bottom Dead Center (BDC) to Top Dead Center (TDC).
Fuel Pump VE Basics
Phase A: Fuel Input
Fuel enters at BDC through the inlet channel and control slot.
Phase B: Fuel Supply
During the upstroke, the inlet is sealed, pressurizing fuel. The distribution slot feeds an injector.
Phase C: End of Power
The discharge port opens, dropping pressure and closing injectors. Travel length depends on slide position.
Function of ELAB Valve
Instantly cuts fuel via a solenoid valve on the distributor head.
Mission of Variable Speed Rotary VE Pump
Varies the roller holder ring’s angular position based on engine speed to compensate for injection delays.
Use of Adaptive Devices (KSB & LFB)
LFB: Adapts injection start or engine load for smoother running by modifying the regulator.
KSB: Improves cold engine performance by advancing injection timing.
Functions of Pressure Regulating Valve in Lucas DPC
- Creates transfer pressure
- Controls pressure vs. rotation speed
- Allows circuit priming
Work Phases in Lucas DPC Hydraulic Head
Admission Stage: Fuel enters, displacing pistons and rollers.
Swing Phase: Rotor rotation connects the distribution channel to an injector, pumping fuel.
Injection Finals: Rollers pass cam crests, ending injection and allowing refill.
Mission of Light Load Progress
Transfer pressure feeds the light load valve via a differential overload valve.
Overload Device Operation
Acts when superimposed on speed-based progress.
Function of Accelerator Motion Shock
Slows throttle lever travel during strong acceleration to prevent engine jerks.