On my 2002 R50 there is a tube that feed air from the battery box to the air box. The entry for this air is regulated by a spring loaded valve. Does anyone have some insight into WHY this is designed the way it is?

My assumption is that as the engine generates more suction when you open the throttle the vacuum in the air box increases and the sprung valve in the air box opens. Is this a way of changing the harmonics of the air intake system? Perhaps it is a way of decreasing air intake noise at low loads? Or maybe the air intake tube from the front of the engine bay cannot provide enough air volume to satisfy the requirements of the engine at high loads? Anyone have an engineering/design take on this? It seems so bizarre to me.

 

This is on found on cars with the "cold weather" option. It draws warm air in from around the battery (fuel atomizes easier in warm air).
The valve is temperature sensitive and opens when it gets cold.