Cruise control

Cruise control (also known as speed control, cruise command, autocruise, or tempomat) is a system that automatically controls the speed of an automobile. The system is a servomechanism that takes over the throttle of the car to maintain a steady speed as set by the driver. Speed control existed in early automobiles such as the Wilson-Pilcher in the early 1900s. They had a lever on the steering column that could be used to set the speed to be maintained by the engine. In 1908, the Peerless included a governor to maintain the speed of the engine through an extra throttle lever on the steering wheel. Peerless successfully used a flyball governor. They advertised their system as being able to "maintain speed whether uphill or down". A governor was used by James Watt and Matthew Boulton in 1788 to control steam engines, but the use of governors dates at least back to the 17th century. On an engine, the governor uses centrifugal force to adjust throttle position to adapt the speed of the engine to different loads (e.g. when going up a hill). Modern cruise control (also known as a speedostat or tempomat) was invented in 1948 by the blind inventor and mechanical engineer Ralph Teetor. He came up with the idea due to being frustrated by his driver's habit of speeding up and slowing down as he talked. A more significant factor in the developing of cruise control was the speed limit imposed in the US during World War II to reduce gasoline use and tire wear. A mechanism controlled by the driver provided resistance to further pressure on the accelerator pedal when the vehicle reached the desired speed. Teetor's idea of a dashboard speed selector with a mechanism connected to the driveshaft and a device able to push against the gas pedal was patented in 1950. He added a speed lock capability that maintained the car's speed until the driver tapped the brake pedal or turned off the system. A 1955 U.S. patent for a "constant speed regulator" was filed in 1950 by M-Sgt Frank J. Riley.