Engine cooling B48: Notes

The engine cooling consists of cooling the coolant and the engine oil. Depending on the version, different types of engine oil cooling are used.

With the B48, the European version has a switchable coolant pump. Engine oil cooling is implemented by means of an oil-to-water heat exchanger.

A turbocharged engine with direct fuel injection makes strong demands on the engine cooling. For this reason, a turbocharger coolant pump is required.

For the cooling system with electric coolant pump, the possibilities of the conventional cooling system are exploited. The heat management determines the current cooling requirement and regulates the cooling system accordingly.

Signals for calculation by the Digital Engine Electronics (DME) are:

• Engine speed
• Load
• Driving speed
• Intake air temperature
• Coolant temperature

On the basis of the above signals, the Digital Engine Electronics (DME) calculates the optimal coolant temperature for each situation. The coolant temperature is influenced by specific heating of the wax element in the characteristic map thermostat as well as requirement-oriented activation of the electric fan. At full load, low coolant temperatures improves the cylinder filling. Furthermore, a low coolant temperature reduces the risk of the engine knocking. This can be a positive influence on the power output and torque.