Heater Circuit Function - GF83.20-P-2003KJE

MODEL 453.091/391/491 

Function requirements, general 

• Drive train operational

Heating circuit, general 

The vehicle interior is not heated via the coolant circuit with the smart e- drive, but exclusively using electricity via the high voltage PTC heater (N33/5). When doing this, the air coming from the blower motor (M2) is heated up via the high voltage PTC heater and flows into the vehicle interior via the blend air flap and the air vents.

For cooling and heating the high-voltage battery (G5) to the operating temperature and cooling the electrical control units of the high voltage drive, the smart e-drive is equipped with low temperature cooling. During driving and preheating mode, the high-voltage control unit box (N83) with all integrated control units and the charger control unit for the high- voltage battery (7 KW charger) (N83/5) are cooled by the low temperature cooling or kept at operating temperature. The high-voltage battery is also cooled via a low-temperature circuit or kept at operating temperature. In order to do this, the electrical coolant pump for the high- voltage battery and power electronics box (M46) pumps the coolant via the cooling ducts of the charger control unit for high-voltage battery (7 KW charger) to the high-voltage control unit box. The coolant absorbs the heat and is heated there. The vast majority of the heated coolant flows from the high-voltage control unit box to the closed-loop control valve of the high-voltage battery cooling and the high-voltage control unit box (Y139/4). Depending on the coolant temperature, the closed-loop control valve for the high-voltage battery cooling and the high-voltage control unit box routes the coolant through the radiator or directly back to the electric coolant pump for the high-voltage battery and the power electronics box.

If required, part of the coolant can be routed via the high-voltage battery cooling closed-loop control valve (Y139/5) and the high-voltage battery heater (R101) to the high-voltage battery for cooling or heating the high- voltage battery. If required, the low-temperature circuit of the high- voltage battery can also be separated from the large low-temperature circuit of the high-voltage control unit box via the high-voltage battery cooling closed-loop control valve. The low-temperature circuit of the high-voltage battery can be heated electrically via the high-voltage battery heater, and the high-voltage battery can therefore be kept at operating temperature.

Detailed information about the coolant circuit can be found in the separate "Thermal management, function" function description.