What is Cruise Control? Exploring Its Functionality and Technology
Cruise control is a technology built into many cars that allows the driver to maintain a consistent speed without the need for constant input from the driver. This feature has been around for decades and has evolved significantly, both in terms of its functionality and technology.
How Cruise Control Functions in Older Cars
In older cars, cruise control operates via a primitive yet effective mechanism. A 'black box' computer receives electrical signals from the gearbox drive shaft or from a sensor in the front wheel, determining the car's road speed. The driver sets the desired speed, input which is then compared to the current speed. This comparison is used to either activate or deactivate a vacuum or an electric servo that controls the throttle linkage, either pulling it in or releasing it based on the return spring action. This process is continually repeated until the desired speed is achieved and maintained until the driver requests a different speed.
Cruise Control in Modern Vehicles
In more modern vehicles, the functionality of cruise control has become more sophisticated, thanks to advanced computer systems and sensor technologies. Modern cruise control systems use multiple computers and numerous sensors to determine the vehicle's speed and adjust the throttle setting with greater precision. Instead of relying on a carburetor throttle valve, these systems use various sensors within the air/fuel intake system and may even use brakes to adjust the speed if necessary.
Historical Perspective on Cruise Control
On even older cars, akin to the author's first car, there was often a lever on the steering column that allowed the driver to manually select their desired throttle setting, thus eliminating the need to constantly use the accelerator pedal. However, the driver was still responsible for the computations required to maintain the target speed, a task that was made much simpler with the advent of cruise control.
Modern Cruise Control Technology
For vehicles manufactured after around 2010, cruise control systems typically use motorized throttle plates, which provide better control and precision. In earlier models, particularly those from the 1980s like the author's 1984 Mercedes-Benz diesel car, throttle control was often achieved through a vacuum-operated cable attached in parallel to the throttle plate controlled by an electric vacuum valve. This system could be felt in the pedal's movement and response. In some cases, a servo-motor operated through a linkage to adjust the injection pump in parallel with the pedal rod linkage, which could be tricky and often required rebuilding.
User Experience and Fun with Cruise Control
The experience of using cruise control can be quite amusing, especially to other drivers who might think that the driver is altering their speed or even trying to mess with them. However, the reality is that cruise control simply maintains a consistent speed set by the driver, reducing the burden on the driver to constantly adjust the throttle. This technology has become so prevalent that it is often used during long drives to maintain a uniform speed, making the journey more comfortable and safer.
Conclusion
Cruise control has come a long way since its primitive beginnings. Today, modern cruise control technology uses advanced computer systems and sensors to ensure a comfortable and efficient driving experience. From the simple lever on the steering column to the sophisticated motorized throttle plates, cruise control continues to adapt to the evolving needs of drivers, increasing both safety and comfort on the road.