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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Power electronics for activation of the electrical machine
The power electronics for the activation of the electrical machine are mainly
made up of the
bidirectional DC/AC converter. It is a pulse converter with a 2-pin DC voltage
connection and a 3-phase
AC voltage connection. This DC/AC converter can work as an inverter and conduct
electrical energy
fr
Malfunction
General information
A Check Control message is displayed.
Vehicle key recognition by the vehicle may malfunction
under the following circumstances:
The battery of the vehicle key is discharged.
Interference of the radio connection from
transmission towers or other equipment with
high transmitt
