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Speed Limiter and Cruise Control – Basics

Speed Limiter and Cruise Control – Basics

We have heard of terms like Speed Limiter, Cruise Control, Adaptive Cruise Control etc. What are they and what are the differences between them. Let us look into some of the basics of each one.

Speed Limiter

A Speed Limiter device is a small electronic device which restricts or limits the maximum speed at which a vehicle can speed. The Speed Limiter is also known as Speed Governors. It is an Intelligent Speed Assistance (ISA) system

The Speed Limiter employs a sensor mechanism which detects how fast the vehicle is moving. This information is communicated to the Engine’s Computer. When a pre-set speed is reached, the Engine Computer restricts the flow of fuel and air to the Engine. Therefore the driver of the vehicle cannot exceed the pre-set top speed.

There are two types of Speed Limiters, Adjustable and Intelligent – Adjustable being the most common one in most cars. The Limit is set by the driver and need to be adjusted if the speed limit changes. Intelligent Speed Assistance system is more advanced, which links the Speed Limit to a Camera which spots speed limit signs. The limiter adjusts automatically when one drives into an area with a different speed limit.

Cruise Control

Cruise Control is a system that automatically controls the speed of a vehicle. The speed is set by the Driver according to his choice and speed-limit of the road. Cruice Control is a Servomechanism that takes over the Throttle of the vehicle to maintain steady speed as per the settings.

Modern Cruise Control was invented in 1948 by a blind Inventor and Mechanical Engineer Ralph Teetor. He got the idea for such a device because he was frustrated by his driver’s speeding and slowing down habit. There are many modifications made on his invention and we have the advanced Cruise Control Systems now.

On the latest vehicles fitted with the Electronic Throttle Control, Cruise Control System can be integrated into the vehicle’s Engine Management System.

Adaptive Cruise Control

Some modern vehicles have Adaptive Cruise Control (ACC) system, which is an improved version of Cruise Control system. Improvements can be Automatic Braking or Dynamic Set-Speed type controls.

Automatic Braking Type uses either a single or combination of sensors to allow the vehicle to keep pace with the car it is following. It slows down the vehicle when closing in on the vehicle in the front and accelerating again to the present speed when traffic allows. Some of them employ early Collision Warning Systems that warn the driver if a vehicle in front comes too close. Dynamic Set-Speed Type uses a GPS position of Speed Limit Signs from a database.

Disclaimer: Information gathered from various sources and provided here for public awareness

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Born and brought up in Kerala, I did my schooling in Kerala and graduated (B.Sc Physics) from the Calicut University. I have worked with a Swedish Company from 1994 to 2015, as a Senior Project Manager in their Group IT Division in Dubai. This blog is the result of my strong desire to communicate with others, sharing what I know and what I could gather from various sources.

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