Monday, Feb 27, 2012
Gulf News
Dubai An automobile expert said that the cruise control system can be jammed if the vacuum diaphragm, inside the actuator, develops a leak.
The cruise control module (CCM), which remembers the set speed of the car, sends pulse signals to the actuator. The actuator then moves the throttle link to bring the vehicle up to the set speed, and then modulates the vacuum to maintain that speed.
The actuator controls the throttle through a vacuum mechanism. If the vacuum diaphragm inside the actuator develops a leak, then the cruise control mechanism will fail. This is also one of the most common cruise control problems. The only way to address the problem is by fixing the leak and restoring the vacuum inside the actuator.
The expert pointed out that cruise control jamming is generally a very rare occurrence, and can also occur due to a corruption in the operating system of the car’s computer.
Do not panic
He added that if the cruise control system jams, motorists should not panic and must remain focused on the road.
“Drivers should be on the lookout for a safe place to stop, shift their transmission to Neutral (N), and then brake lightly. If it doesn’t work, try switching off your car with the ignition switch key. Motorists should also familiarise themselves with alternative ways to switch off their cars by checking the car manual,” the expert said.
“If not successful, drivers should press the brakes, and then gradually and slowly apply the handbrake,” he added.
The expert pointed out that this type of failure is very rare, but that it is important that motorists ensure that their car is serviced regularly to prevent it from occurring. He said that when used properly and responsibly, cruise control is relatively safe.
“Motorists should not use cruise control in crowded areas. It is best used on open roads that are free of traffic, and when the motorist is on a long journey.
“However, the system is best avoided when the motorist is drowsy, under medication, or in any other state that compromises his/her focus,” he said.
Fact file
What is cruise control?
A cruise control system, also known as speed control or autocruise, is designed to accurately maintain a driver’s desired set speed without intervention from the driver, by actuating the throttle — accelerator pedal linkage. Speed control with a centrifugal governor was used in cars as early as 1910, while modern cruise control – also known as speedostat – was invented in 1945 by the blind American inventor and engineer Ralph Teetor, who also built his first real-life car at the age of 12. In a modern automotive cruise control, a control loop takes over control of the throttle, which is normally controlled by the driver with the gas pedal, and holds the vehicle speed at a set value. Cruise control systems are designed to turn off immediately with a slight touch of the brake or clutch pedal, and most controls will cut out if the driver accidentally shifts from drive to neutral.
— Gulf News Report
By Mohammad Al Jashi?Staff Reporter
Gulf News 2012. All rights reserved.
