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What is cruise control in a car? and how does it work?


A system that automatically regulates a vehicle's speed is known as cruise control, sometimes referred to as speed control, autocruise, or tempo mat in some regions. The system, which consists of a servomechanism, controls the car's throttle to keep the vehicle moving at the driver-specified speed. cruise control icon as it appears frequently on dashboards.


In the Wilson-Pilcher and Peerless vehicles of the 1900s and 1910s, speed control was a common feature. The Peerless system promised to "keep speed whether uphill or down." James Watt and Matthew Boulton used the technique in 1788 to regulate steam engines, however governors had been in use since at least the 17th century. To keep an engine running at a speed that is close to constant while under varied loads, the governor will modify the throttle position.

The modern cruise control system was created in 1948 by mechanical engineer and inventor Ralph Teetor. It is often referred to as a speed stat or tempo mat. His inspiration came from the aggravation of being in a car with his lawyer, who kept accelerating and decelerating as he spoke. The 1958 Imperial (dubbed "Autopilot") was the first vehicle to use Teetor's technology, which used a speed dial on the dashboard. This technique employed a bi-directional screw-drive electric motor to adjust the throttle position as necessary and determined ground speed based on driveshaft rotations off the revolving speedometer-cable.

M-Sgt Frank J. Riley submitted a 1955 U.S. patent application for a "Constant Speed Regulator" in 1950. In 1948, he put his creation—which he came up with while traveling down the Pennsylvania Turnpike—onto his personal vehicle. Independent of Riley, Harold Exline created a similar form of cruise control, which he initially put in his own vehicle and the vehicles of his friends. The "Vacuum Powered Throttle Control with Electrically Controlled Air Valve" U.S. Patent was submitted by Exline in 1951, and it was approved in 1956. Riley, Exline, and the future patent owners were unable to get royalties for any of the innovations that used cruise control in spite of these patents.

For its large-sized automobiles with automatic transmissions, American Motors (AMC) launched a low-cost automatic speed control in 1965. Once the required speed was attained, the AMC "Cruise-Command" unit was activated with a push-button, and the throttle position was changed using a vacuum control that was connected to the speedometer cable rather of a separate dial on the dashboard.

In 1968, while working as an engineer for RCA's Industrial and Automation Systems Division in Plymouth, Michigan, Daniel Aaron Wisner created "Automotive Electronic Cruise Control." The first electronic device for operating an automobile was his innovation, which was covered by two patents published that year (US 3570622 & US 3511329), the second of which modified his initial concept by including digital memory. Two decades passed until an integrated circuit for his invention was built by Motorola as the MC14460 Automotive Speed Control Processor in CMOS. The ability to be combined with electronic engine management and accident prevention systems gave electronic speed control an edge over its mechanical predecessor.


The driver must physically accelerate the car before pressing a button to adjust the cruise control to the current speed.

The drive shaft of the vehicle, the speedometer cable, the wheel speed sensor, the engine's revolutions per minute, or electronically generated internal speed pulses are all sources of the speed signal used by the cruise control. Most systems include a speed limit, usually approximately 25 mph (40 km/h), below which the cruise control cannot be used. If the vehicle employs a "drive-by-wire" system, the intended speed will be maintained by a solenoid pulling the throttle cable, a vacuum-driven servomechanism, or the entirely electronic electrical systems incorporated into the car.

Any cruise control device must be able to be turned off both manually and automatically when the driver depresses the brake, and frequently also the clutch. Cruise control frequently has a coast capability to slow down without braking and a memory feature to resume the programmed speed after braking. The automobile may still be accelerated when in cruise control mode; but, as soon as the accelerator is let off, the vehicle will begin to slow down until it achieves the predetermined speed.

The most recent automobiles with electronic throttle control may simply integrate cruise control into the engine management system. Modern "adaptive" systems have the capability to automatically slow down when approaching a vehicle in front or when the posted speed limit is approached. For individuals who are driving in uncharted territory, this is advantageous.

Adaptive cruise control (ACC), a broad name for better cruise control, is a feature of several contemporary automobiles. Automatic braking or dynamic set-speed controls are two examples of these advancements.

Automatic Braking Type: The automatic braking type uses one or several sensors (radar, lidar, and camera) to keep up with the car it is following, slow down when it gets close to the automobile in front, and then accelerate back up to the predetermined speed when the traffic permits. Additionally, some systems have forward collision warning systems that alert the driver if a car in front approaches too closely given the speed of both cars (within the preset headway or braking distance).

Type of Dynamic Set Speed: A database of GPS coordinates for speed restriction signs is used to determine the dynamic set speed. Some can be altered by the driver.

Type of Non-Braking: The speed can be changed to help with traffic control.

Using a camera and millimeter-wave radar, dynamic radar cruise control automatically slows down or speeds up the automobile in response to the cars in front of it in order to maintain a certain distance from them.

According to SAE International, vehicles incorporating adaptive cruise control are Level 1 autonomous vehicles.

Use the cruise control only on freeways. In situations when you can travel mostly without needing to stop or slow down, cruise control is best employed. In-depth Source X Driving instructor expert interview: Simon Miyerov. 2019 December 4. It is perfect for using on highways and freeways. Due of the constant stopping and starting required when driving on congested city streets, cruise control is useless. X Information source It might also be risky to use cruise control on congested roadways. You can be paying less attention if you aren't fully in charge of your automobile. Accident risk may increase if you brake or respond to other vehicles more slowly than usual.

Your car might not be equipped with Traffic-Aware Cruise Control, or the functionality might not function precisely as stated, depending on the market region, vehicle configuration, options selected, and software version. For information on using Cruise Control if your car isn't equipped, consult the owner's handbook on the touchscreen in your car.


The following are some benefits of cruise control:

  • Its value for lengthy travels across motorways and sparsely inhabited routes (reducing driver weariness, boosting comfort by permitting positional adjustments more safely).

  • Some motorists employ it to prevent unintentionally exceeding speed restrictions. A driver who would typically raise their speed on the highway could restrain themselves from doing so.

  • higher fuel economy

However, misuse of cruise control can result in accidents for a number of reasons, including:

  • rushing around corners where caution is called for

  • difficult or slippery ground that can impair the cruise control controls

  • Wet or rainy conditions might cause traction to be lost.

  • encourages motorists to drive less attentively, which raises the possibility of an accident

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