Engine cooling system thermal management, function

G20.00-3134-76

General

The engine cooling heat management optimizes the efficiency of the engine and thus reduces fuel consumption. This is achieved by targeted and as-required actuation of the following components:

 Coolant pump

 Fan clutch

As a result of the regulation of the coolant pump, the coolant flow rate is reduced by the engine to the necessary dimension in the respective operating status. In addition, the cool air flow rate of the radiator is controlled via the fan clutch depending on the operating status.

Coolant pump magnetic clutch regulation (viscous)

The delivery rate of the coolant pump is continuously variable. The actuation of the magnetic clutch (viscous) takes place via the engine management (MCM) control unit (A4) via a pulse width modulated signal. The engine management (MCM) control unit (A4) assesses the following information for this purpose:

 Coolant temperature

 Engine speed

 Engine throttle condition

 Coolant pump rotational speed (recorded by coolant pump rpm sensor (B640))

 Compressor operating status (active/idle)

Depending on the listed information, the engine management (MCM) control unit (A4) calculates the corresponding manipulated variable for the actuation of the coolant pump solenoid valve (Y631).

Electromagnetic regulation of the viscous fan clutch

The delivery rate of the electromagnetic viscous fan clutch is continuously variable. The actuation takes place via the engine management (MCM) control unit (A4) via a pulse width modulated signal.

The engine management (MCM) control unit (A4) assesses the following information for this purpose:

 Coolant temperature

 Engine oil temperature

 Charge air temperature

 Engine speed

 Fan speed (recorded by fan rpm sensor (Y616 b1))

Depending on the listed information, the engine management (MCM) control unit (A4) calculates the manipulated variable for the actuation of the fan clutch solenoid valve (Y616).