Cruise Control mounted on a 2000 Jeep Grand Cherokee Steering Wheel

Cruise control (sometimes known as speed control or Autocruise) is a system that automatically controls the rate of motion of a motor vehicle. The driver sets the speed and the system will take over the throttle of the car to maintain the same speed. In software development, CruiseControl is a Java-based framework for a continuous build process. ... In an engine, the throttle is the mechanism by which the engines power is increased or decreased. ...

History

Speed control with a centrifugal governor was used in automobiles as early as the 1910s, notably by Peerless. Peerless advertised that their system would "maintain speed whether up hill or down". The technology was invented by James Watt and Matthew Boulton in 1788 to control steam engines. The governor adjusts the throttle position as the speed of the engine changes with different loads. A centrifugal governor is a specific type of governor that controls the speed of an engine by regulating the amount of fuel admitted, so as to maintain a near constant speed whatever the load or fuel supply conditions. ... // The 1910s represent the culmination of European militarism which had its beginnings during the second half of the 19th Century. ... Peerless Motor Company factory, circa 1910s Peerless emblem Peerless Model 56 7-Passenger Touring 1917 Frank Hersheys aluminum bodied Peerless, designed while he was employed by Murphy Body Works. ... For other persons named James Watt, see James Watt (disambiguation). ... Matthew Boulton. ... 1788 was a leap year starting on Tuesday (see link for calendar). ... // The term steam engine may also refer to an entire railroad steam locomotive. ...

Modern cruise control (also known as a speedostat) was invented in 1945 by the blind inventor and mechanical engineer Ralph Teetor. His idea was born out of the frustration of riding in a car driven by his lawyer, who kept speeding up and slowing down as he talked. The first car with Teetor's system was the Chrysler Imperial in 1958. This system calculated ground speed based on driveshaft rotations and used a solenoid to vary throttle position as needed. Year 1945 (MCMXLV) was a common year starting on Monday (link will display the full calendar). ... Ralph Teetor, a prolific (and blind) inventor, invented cruise control. ... The Chrysler Corporation was a United States-based automobile manufacturer that existed independently from 1925–1998. ... For Imperial models sold under its own marque (1955-1975, 1981-83) see Imperial (automobile) The Chrysler Imperial, introduced in 1926, was the companys top of the range vehicle for much of its history. ... Jan. ... This article is about the mechanical device. ... For other uses, see Solenoid (disambiguation). ...

Theory of operation

In modern designs, the cruise control may or may not need to be turned on before use — in some designs it is always "on" but not always enabled, others have a separate "on/off" switch, while still others just have an "on" switch that must be pressed after the vehicle has been started. Most designs have buttons for "set", "resume", "accelerate", and "coast" functions. Some also have a "cancel" button. Alternatively, tapping the brake or clutch pedal will disable the system, a required feature to prevent the vehicle from accelerating against braking as it attempts to maintain speed. The system is operated with controls easily within the driver's reach, usually with two or more buttons on the steering wheel spokes or on the edge of the hub like those on Honda vehicles, on the turn signal stalk like in some General Motors vehicles or on a dedicated stalk like those found in Toyota and Mercedes-Benz vehicles. Early designs used a dial to set speed choice. This article is about the vehicle component. ... For other uses, see Clutch (disambiguation). ... An automobile has usually three pedals. ... A modern road cars steering wheel Steering wheels from different periods A steering wheel is a type of steering control used in most modern land vehicles, including all mass-production automobiles. ... This article is about the Japanese motor corporation. ... Turn signals (US English) or indicators (British English) are a set of lights on a vehicle (be it a car, truck/lorry, tractor, motorcycle, etc. ... General Motors Corporation, also known as GM, is a multinational corporation headquartered in the United States and has been the worlds largest and most dominant automaker since 1931 till the second half of 2007, surpassed by Toyota; as well as the global industry sales leader for 77 years. ... Toyota Motor Corporation ) is a multinational corporation headquartered in Japan, and currently is the worlds largest automaker. ... This page is about the Mercedes-Benz brand of automobiles and trucks from the DaimlerChrysler automobile manufacturer. ...

The driver must bring the car up to speed manually and use a button to set the cruise control to the current speed. The cruise control takes its speed signal from a rotating driveshaft, speedometer cable, speed sensor (found on the wheels) or from the engine's RPM. Most systems do not allow the use of the cruise control below a certain speed (normally 35 mph/55 km/h) to discourage use in city driving. The car will maintain that speed by pulling the throttle cable with a solenoid or a vacuum driven servomechanism. This article is about the mechanical device. ... Speedometer gauge on a car, showing the speed of the vehicle in miles and kilometres per hour on the out– and inside respectively. ... rpm or RPM may mean: revolutions per minute RPM Package Manager (originally called Red Hat Package Manager) RPM (movie) RPM (band), a Brazilian rock band RPM (magazine), a former Canadian music industry magazine In firearms, Rounds Per Minute: how many shots an automatic weapon can fire in one minute On... In an engine, the throttle is the mechanism by which the engines power is increased or decreased. ... Look up Vacuum in Wiktionary, the free dictionary. ... Small R/C servo mechanism 1. ...

Most systems can be turned off both explicitly and automatically, when the driver hits the brake or clutch. Cruise control often includes a memory feature to resume the set speed after braking and a coast feature to reset the speed lower without braking. When the cruise control is in effect, the throttle can still be used to accelerate the car, but once the accelerator is released the car will then slow down until it reaches the previously set speed.

On the latest vehicles fitted with electronic throttle control, cruise control can be easily integrated into the vehicle's engine management system. Cruise controls currently being developed include the ability to automatically reduce speed when the distance to a car in front, or the speed limit decreases. This is an advantage for those driving in unfamiliar areas. Electronic throttle control (ETC) is an automobile technology which severs the direct link between the accelerator pedal and the throttle. ... An electronic control unit (ECU) (also known as an engine management system) is an electronic device, basically a computer, in an internal combustion engine that reads several sensors in the engine and uses the information to control the fuel injection and ignition systems of the engine. ...

Advantages and disadvantages

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Cruise control has many advantages but also some serious vices^{[citation needed]}.

Some of those advantages include:

• Its usefulness for long drives across sparsely populated roads. This usually results in better fuel efficiency.
• Some drivers use it to avoid unconsciously violating speed limits. A driver who otherwise tends to unconsciously increase speed over the course of a highway journey may avoid a speeding ticket. Such drivers should note, however, that a cruise control may go over its setting on a downhill which is steep enough to accelerate with an idling engine.

However, cruise control can also lead to accidents due to several factors, such as: For other uses, see Road (disambiguation). ...

• The lack of need to maintain constant pedal pressure, which can help lead to accidents caused by highway hypnosis or incapacitated drivers; future systems may include a dead man's switch to avoid this.
• When used during inclement weather or while driving on wet or snow- and/or ice-covered roads, the vehicle not equipped with Electronic Stability Control could go into a skid. Stepping on the brake — such as to disengage the cruise control — often results in the driver losing control of the vehicle.

Driving over "rolling" terrain, with gentle up and down portions, can usually be done more economically (using less fuel) by a skilled driver viewing the approaching terrain, by maintaining a relatively constant throttle position and allowing the vehicle to accelerate on the downgrades and decelerate on upgrades, while reducing power when cresting a rise and adding a bit before an upgrade is reached. Cruise control will tend to overthrottle on the upgrades and retard on the downgrades, wasting the energy storage capabilities available from the inertia of the vehicle. The inefficiencies from cruise control can be even greater relative to skilled driving in hybrid vehicles. Highway hypnosis is a mental state in which the person can drive an automobile great distances, responding to external events in the expected manner, with no recollection of having consciously done so. ... A dead mans switch (for other names, see Alternative names), as its name suggests, is a device intended to stop a machine in case the human operator becomes incapacitated, and is a form of fail-safe. ... Electronic stability control (ESC) is a computerized technology that improves the safety of a vehicles handling by detecting and preventing skids. ... For other types of hybrid transportation, see Hybrid vehicle (disambiguation). ...

Many countries establish that it is illegal to drive within city limits with the cruise control feature activated.^{[citation needed]}

Adaptive cruise control

Main article: Adaptive cruise control

Some modern vehicles have adaptive cruise control (ACC) systems. These use either a radar or laser setup to allow the vehicle keep pace with the car it is following, slow when closing in on the vehicle in front and accelerating again to the preset speed when traffic allows. Some systems also feature forward collision warning systems, which warns the driver if a vehicle in front - given the speed of both vehicles - gets too close (within the preset headway or braking distance). It has been suggested that this article or section be merged into Cruise control. ... For other uses, see Radar (disambiguation). ... For other uses, see Laser (disambiguation). ... Some modern vehicles have forward collision warning (FCW, FCWS) systems, also known as front collision warning systems, collision warning systems (CWS) and rear end collision warning systems. ...

References

This article does not cite any references or sources. (May 2008) Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed.

External links

• Overview of intelligent vehicle safety systems
• Intelligent Transport Systems
• Preventive safety applications and technologies
• Article at HowStuffWorks
• Cruise [Un]Control: Driver sets the cruise control on his vehicle, then slips into the backseat for a nap at Snopes.com