The gasoline diaphragm pump in a car is operated by a cam geared directly to rotating parts of the engine. The cam pushes a pushrod. The brown rod shown in this drawing is moved by the pushrod. Fuel pumps like this one operate continuously but have a safety valve which returns fuel to the input side of the pump if pressure rises above a set level. The pump usually has a fuel filter built into it.
Diaphragm pumps are very common and come in many sizes.
Modern plastics are flexible and long lasting making this an ideal low-maintenance pump for many applications. See also Double Diaphragm Pumps .