BMW 3: Fuel high-pressure pump
The single-piston high pressure pump by Bosch, well-known from the B46 engine, is used. The high pressure pump HDP6 is driven by a triple cam which is attached to the exhaust camshaft. To be able to accommodate a fuel system pressure of 350 bar (5076 psi), the pump piston and tappet have been modified.
Low pressure fuel is supplied to the high pressure pump via the in tank electric fuel pump.
Bosch high-pressure pump HDP6
- Low-pressure connection
- High-pressure connection
- Balancing chamber
- High-pressure non-return valve
- Pressure-limiting valve
- Pump piston
- Fuel fuel quantity control valve
- Electrical connection of fuel quantity control valve
The fuel quantity control valve at the high pressure pump adjusts the fuel pressure in the rail. The maximum pressure in the rail is 350 bar (5076 psi); it is kept throughout the engine's entire operating range. The fuel pressure is only reduced to 150 bar (2175 psi) during idling. The high pressure pump contains a pressure limiting valve which opens at a pressure of 400 bar (5801 psi). The fuel quantity control valve is activated via a Pulse-Width-Modulated (PWM) signal and assumes the open position in the de-energized state. This means the pump piston of the high pressure pump cannot compress the fuel.
The high pressure pump in the high-pressure fuel system cannot build up pressure if the fuel quantity control valve is pulled off. In this situation, the maximum low fuel pressure of 5.8 bar (84 psi) would be present in the rail during an engine start. The system would be in emergency operation. To ensure the engine remains capable of running in this state, the opening period of the solenoid valve injectors has been extended and the idle speed increased. Although the vehicle remains drivable, the maximum engine performance is not available.
Due to the high fuel pressures, the fuel lines must never be detached when the engine is in operation.
When removing the high pressure pump, follow the specifications in the current repair instructions.
Excessive tilting of the pump can damage the pump piston!
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Direct rail
Injector mounting
Mounting bolts
Plastic sleeve (not required to be reinstalled after taken apart for
service)
Holding clamp with bayonet fitting
Rail
Solenoid valve injector
Casting lug
Th
Solenoid valve injector
Measures at the solenoid valve injector
The following graphic illustrates the differences between the HDVE5 and HDEV6
fuel injectors:
Solenoid valve injectors
Solenoid valve injector HDEV5
Soleno
Engine Electrical System
Digital Motor Electronics (DME)
DME 8 control unit
The Digital Motor Electronics (DME) is the computing and switching center.
Sensors on the engine
and the vehicle deliver the input signals and actu
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General information
Video files and, depending on the vehicle equipment,
video DVDs can be played. Sound is
played back through the vehicle loudspeakers.
Settings are stored for the driver profile currently
used.
The video image on the front Control Display is
switched off when a country-dependent speed is
exceeded.
Idle state
Concept
If the vehicle is in idle state, it is switched off. All
power consumers are deactivated.
General information
The vehicle is in idle state prior to opening from
the outside and after exiting and locking.
Safety information
Warning
An unsecured vehicle can begin to move and
possibly roll awa
