What shape is the throttle of a car? That's true.

Throttle is colloquial and colloquial, and the technical term is "throttle". It is an adjustable switch located at the air inlet of automobile gasoline engine, which can control the air intake of the engine. The throttle of modern automobile is not a single part, but a complex assembly.

In the picture, the pipe is an intake pipe, and the blades with bolts in the pipe are throttles to control the air flow, which are closed in the picture.