All right.
I had to recall I had downloaded a few "technical training" documents before ordering the car. Here we are (in my own translation
).
The belt drive includes the main belt drive with the alternator and the air conditioner compressor and and additional belt drive with a friction wheel and the coolant pump. The main drive has a tensioner, the additional one does not.
1. Crankshaft pulley.
2. Belt.
3. Belt tensioner.
4. Alternator pulley.
5. Air conditioner compressor pulley.
6. Friction wheel drive.
7. Coolant pump.
The N13 engine's coolant pump is driven with a friction wheel. In a de-energized state of the friction wheel actuator the friction wheel is pressed against the crankshaft pulley and the coolant pump with a spring. The coolant pump is driven with a friction wheel that looks like a pulley with a belt attached.
The back side of the belt on the crankshaft pulley rotates the friction wheel. The friction wheel, in turn, drives the coolant pump. This design allows to do without another belt drive. This allows for better use of the mounting space and makes the design shorter and compact. Due to less side forces on the coolant pump shaft the pump's housing can be completely plastic. The plastic housing facilitates flows and the coolant pump's performance.
1. Attachment screw.
2. Case cover.
3. Maintenance handle.
4. maintenance tape.
5. Spring.
6. Eccentric.
7. Top mount.
8. Case cover.
9. Electric motor.
10. Plug-in contact.
The thermoregulation system detects the need for cooling at the particular moment and regulates the cooling system accordingly. In some working states the coolant pump can be completely off, for example, for quick coolant heating at warming up. Besides that the auxiliary coolant pump responsible for cooling of the turbocharger can be turned on and off. That is, cooling intensity can be set independently of the engine crankshaft revs. The thermoregulation system is capable of turning on and off both the mechanical coolant pump and the electrical auxiliary coolant pump depending on the need and also of executing the adjustment of the programmable thermostat. Thus the engine control system can adjust the coolant temperature to the traffic situation. These measures allow additional fuel saving.