Jetta's throttle body is connected to two water pipes. What's the effect?

The water pipe here is used to heat the throttle body! Because the climate in the north is cold. The air velocity at the throttle is large, and it is easy to freeze in winter! In order to avoid this situation, hot water is pumped from the cylinder head to heat the throttle body, which belongs to a small cycle. The water temperature is kept at about ninety degrees. Note that there are two black pipes at the front and back of the throttle body, namely the positive crankcase ventilation system (PCV).

This is exactly what we did in the practice of automobile manufacturing the other day.