P20.10-2544-79
Example illustration of mechanical coolant pump |
1 | Coolant pump |
Overview
This document contains information on:
General
Function
General
Allow coolant pump to circulate the coolant in the coolant circuit. The coolant pump is driven in different ways depending on the engine and design. The following types of drive are commonly used:
Belt drive, using a toothed belt for example
Chain drive, using a timing chain for example
Electric, in engines with 48 volt on-board electrical system
Function
Mechanical coolant pump
The mechanical coolant pump uses the rotation of the crankshaft for drive purposes. The rotational movement is transferred to the drive wheel of the coolant pump via a toothed belt or poly-V-belt or a timing chain.
The drive wheel is connected to an impeller, which sends the coolant around the coolant circuit.
The disadvantage of mechanical coolant pumps is that they are permanently coupled to the engine speed. This results in high coolant throughput, e. g. when driving on the freeway, but low throughput when demand is high in the city or in stop-and-go traffic.
P20.10-A062-79
Example illustration of electric coolant pump |
2 | Electric coolant pump |
Electric coolant pump
Electrically driven coolant pumps operate independently of the engine speed. The cooling output is adapted to the cooling requirements. As a result, the operating temperature is achieved faster and kept constant.
The electric coolant pump that is used is a centrifugal pump driven by a brushless electric motor. The electrical coolant pump can be operated by an electronic control upon request.
Due to their better efficiency, electric coolant pumps also help to save fuel.
The electrical coolant pump is actuated by the combustion engine control unit. When this occurs, it is regulated after the following signals have been evaluated:
Coolant temperature
Heater request
Engine speed
Engine torque
At a coolant temperature under 75 °C, the electrical coolant pump is deactivated unless a request occurs in the electrical coolant pump.
The operating temperature of the electric coolant pump is between -40 °C and 150 °C ambient temperature (for max. 30 minutes), 120 °C for continuous operation. The coolant temperature should lie between -10°C and a maximum of 125°C.
If the coolant pump loses communication, an integrated limp-home mode also ensures sufficient engine cooling in the event of malfunction.