Turbocharger Coolant Pump: Description and Operation

Turbocharger Coolant Pump

Turbocharger coolant pump
Due to the turbocharging and the compact arrangement of the exhaust turbocharger in the V-room the N63 engine generates a lot of heat. Great importance is attributed to the cooling accordingly. The bearing seats of the exhaust turbocharger are cooled separately by the turbocharger coolant pump. In particular, retained heat from the turbochargers is dissipated after the engine is stopped. The turbocharger coolant pump is integrated in the engine cooling circuit.

Functional description
The electrical turbocharger coolant pump works according to the principle of a centrifugal pump. The turbocharger coolant pump is at an angle behind the expansion tank of the cooling circuit for the charge air cooling. The engine control directly activates the turbocharger coolant pump (not via local interconnect network bus like the coolant pump for the charge air cooler).







Activation of the electrical turbocharger coolant pump takes into account the following variables:
- Coolant temperature at engine outlet
- Engine oil temperature
- Injected fuel quantity

The injected fuel quantity is used to calculate the heat contribution to the engine. The function is similar to that of heat management in the 6-cylinder engines. The after-run of the turbocharger coolant pump can last up to 30 minutes. To improve the cooling effect, the electric fan is also switched on. The electric fan runs down for a maximum of eleven minutes.

Structure and inner electrical connection
The turbocharger coolant pump is connected by means of a 3-pin plug connection. The actuating wire serves as a diagnostic cable at the same time.







Characteristic curve and setpoint values
There is no speed control for the turbocharger coolant pump (despite the design of the pulse width modulation). The turbocharger coolant pump has an operating point of 2750 rpm. Furthermore, the coolant pump is not suitable for operation with a permanent pulse. In addition, the coolant pump can be switched to low power via the activation connection.







Observe the following setpoint values for the turbocharger coolant pump:

Size Value
Speed (operating point) 2750 rpm

Supply rate (nominal 800 l/h
operation)

Voltage range (full 9 to 16 V
power output)

Maximum current consumption 1.2 A to 1.4 A
in normal operating mode

Temperature range of -40 to 135 °C
coolant temperature

Temperature range -40 to 140 °C

Diagnosis instructions

Failure of the component

The following behavior can be expected if the turbocharger coolant pump fails:
- Fault entry in the engine control unit
- Emergency operation with substitute value

General notes

Diagnosis is started at ignition on.
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