Heat management
The possibilities of conventional cooling systems are used for the cooling system with electrical coolant pump.
The following components are influenced by the heat management:
- Electrical coolant pump
- Mapped thermostat
- Digital engine electronics (DME)
The cooling output of the system is adapted by means of a freely variable volumetric flow of the coolant.
The heat management determines the current cooling requirement and regulates the cooling system accordingly. If necessary, the coolant pump can even be switched off altogether, for example to heat up the coolant quickly during the warm-up phase.
If the engine is not running but very hot, the coolant pump will also work while the vehicle is out of use. Cooling output can thus be called up regardless of engine speed.
The heat management now permits various characteristic maps to be used as a basis for controlling the coolant pump, over and above the map thermostat. In this way, the engine control unit can adapt the engine temperature to the driving characteristics.
The engine control unit regulates the following temperature ranges:
- 112°C = Economy
- 105°C = Normal
- 95°C = High
- 80 C = High and regulation by the map thermostat
If the vehicle handling causes the engine control unit to detect the economical operating range Economy, the DME regulates to a higher temperature (112 C).
In this temperature range, the engine is operated with a relatively fuel requirement. The friction inside the engine is reduced at higher temperature. The temperature increase thus favors lower fuel consumption in the low load range.
In the High and regulation by the map thermostat mode, the driver wants to use optimized power output development of the engine. To achieve this, the temperature in the cylinder head is lowered to 80°C. This lowering leads to a better cylinder filling, which leads in turn to an increase in engine torque. The engine control unit can now regulate a certain operating range, adapted to the relevant driving situation. This makes it possible to use the cooling system to influence consumption and performance.