Why is the crankcase ventilation pipe connected to the throttle?

The reason why the crankcase ventilation pipe is connected to the throttle valve is the requirement of environmental protection on the one hand, and the gas is pumped out of the crankcase by using the negative pressure of intake air on the other hand. When the oily steam reaches the intake pipe and cools, the oil in it will condense on the intake and throttle valve, and then the carbon deposit in the steam will also be deposited on these parts. Because the air flow is the largest in the gap where the throttle valve is opened, the space is small and the gas temperature is low, this part is the easiest to condense.