Radiator Cooling Fan: Description and Operation

GF83.40-P-2192RT Engine/AC Electric Suction Fan, Component Description

Component Identification:

Location
The suction fan is located behind the radiator.

Task
The suction fan serves for cooling the coolant from the engine and the refrigerant from the air conditioning.

Function
Depending on the refrigerant pressure, and/or the coolant temperature and outside temperature, the speed of the engine and AC electric suction fan with integrated control is increased continuously.

Actuation of the engine and AC electric suction fan with integrated control is calculated for the front refrigerant circuit by the AAC [KLA] control and operating unit (N22) or by the comfort AAC [KLA] control and operating unit (N22/7).

The AAC [KLA] control and operating unit or comfort AAC [KLA] control and operating unit sends the information over CAN-B to the EIS [EZS] control unit (N73) and then over CAN-C to the ME-SFI [ME] control unit (N3/10). The ME-SFI [ME] control unit also receives the current coolant temperature via the coolant temperature sensor (B11/4) and forwards this information for regulation to the control unit integrated in the engine and AC electric suction fan with integrated control.
The front SAM control unit (N10) receives the refrigerant pressure from the refrigerant pressure sensor (B12) and the outside temperature from the outside temperature display temperature sensor (B14).

The input information received by the control unit integrated into the engine and AC electric suction fan with integrated control are compared against stored values and if necessary the rotational speed of the engine and AC electric suction fan with integrated control is increased to 100 %.
The engine and AC electric suction fan with integrated control runs at 25 % output when the air conditioning systems are switched on for basic ventilation.


The basic ventilation can be switched off under the following conditions:

^ At an outside temperature ≤ 15 °C
^ At a ground speed > 70 km/h or 45 mph

Each pressure-dependent speed of the engine and AC electric suction fan with integrated control is retained.

Cut in of the electric suction fan engine and AC with integrated control
The electric suction fan engine and AC with integrated control is actuated at the following values:

^ Refrigerant pressure < 12 bar = Suction fan ON (25 %)
^ Refrigerant pressure > 20 bar = Suction fan ON (100 %)
^ Refrigerant pressure 12 to 20 bar = (25 to 100 %)

A run-on time of 60 s can be set in order to ensure that the engine and AC electric suction fan with integrated control will continue to operate even where the refrigerant compressor is temporarily switched off by the anti-icing protection.