The engine cooling system
High temperatures occur in the engine during combustion. To prevent the engine being damaged by overheating, it needs to be cooled. One option for doing this is air cooling. However, most engines are water-cooled. The cooling liquid absorbs the heat from the engine block and cylinder head and releases it into the ambient air through the radiator. The water pump – also known as a coolant pump – is responsible for conveying this liquid.
Types of water pumps
Mechanical water pumps are usually driven directly by the engine. The power consumption of the water pump thereby increases in line with the engine speed. But even during idling, sufficient engine cooling must also be guaranteed for all operating states. Conventional water pumps are therefore oversized for most operating states.
On electrical water pumps, the power consumption can be controlled electronically depending on the extent to which the engine needs to be cooled. This demand-based control reduces fuel consumption and, in turn, pollutant emissions.