The "sound valve" in the sports car's exhaust system:

Many high-performance vehicles (such as Ferraris, Porsches, or modified cars) have a "variable exhaust system". When you switch to the sport mode, an electronic butterfly valve in the exhaust pipe will open, allowing the exhaust gas to bypass the muffler and be discharged directly, instantly unleashing a fierce roar.

The "throat" of the car engine:

The throttle body found in traditional fuel vehicles is essentially a precise butterfly valve controlled by a computer or the accelerator pedal. It regulates the amount of air entering the engine by changing its rotational angle.