Intake Air Heater: Description and Operation

Engine Ventilation Heating

Engine ventilation heating
The diesel engine has engine ventilation heating. The engine ventilation heating is located at the inlet to the clean air pipe. The engine ventilation heating is optional equipment (SA 842 Cold-climate version).

Functional description
The engine ventilation heating is required for countries with very low temperatures in the winter to prevent the ventilation line from "freezing". The flow into the differentiated air intake system can freeze at constant-speed driving and temperatures below -25 °C as well as in extreme short-distance driving. A heating element according to the PTC principle is used.







Structure and inner electrical connection
Resistors with a positive temperature coefficient (PTC) are designated as PTC resistors. The warmer the PTC becomes, the higher its resistance. With a PTC, high current flows at switch on, for example. With increasing heating, this level of current falls. Metals are PTC conductors. Their resistance increases with rising temperature.







Switch-on conditions and set point values
The engine ventilation heating is activated in the following conditions:
- Terminal 15 on
- Ambient temperature less than 2°C
- Less than 360 seconds have elapsed following engine start (time increases depending on engine oil temperature, coolant temperature and driving speed)

Please note the following target values for the engine ventilation heating:

Size Value
Supply voltage 12 V
Resistance at 25 °C 12 to 18 Ohms
Temperature range -40 to 140 °C

Diagnosis instructions

Failure of the component
If the engine ventilation heating fails, the following behavior is to be expected:
- Fault entry in the engine control

We can assume no liability for printing errors or inaccuracies in this document and reserve the right to introduce technical modifications at any time.