30-08-2014, 03:46 PM
OVER SPEED INDICATOR AND ACCIDENT AVOIDANCE SYSTEM IN FOUR WHEELERS
OVER SPEED INDICATOR.doc (Size: 149.5 KB / Downloads: 18)
Abstract
Except for the Autobahn in Germany, almost all roads have specific speed limits. And it is difficult for the driver to always look out for speed limits signs and adjust his speed accordingly. Over speed indicator is a device that tells the driver if he is exceeding the particular speed limit. With the over speed indicator in your car you can be sure that you are not going get yourself booked for over speeding. The system has a computer which stores the speed limits of different areas. The GPS in the system feeds the exact location of the car to the computer which looks up in its database to determine the permissible speed for the area and limits the car within the allowable speed. Accident Avoidance systems (AAA) in a four wheeler is a cocktail of several technological marvels which is the focus of this paper and we present six such AAA’s in detail.
Emergency Brake Assist (EBA)
In an emergency, many people do not depress the brake pedal hard enough. EBA senses an emergency braking situation and helps the driver to reduce speed in the shortest distance possible.
An optimised braking system that gives a shorter braking distance of 5 to 9 metres
Dynamic Stability and traction Control (DSTC)
DSTC makes driving on twisty and slippery road conditions safer, by using sensors to detect whether any of the wheels is losing traction. DSTC has the ability to cut power in a flash, helping the car to regain its grip. If in any case the car shows a tendency to skid the system automatically slows the particular wheels to help maintain control
Electronic brake distribution (EBD)
Electronic brakeforce distribution(EBD or EBFD), Electronic brakeforce limitation(EBL) is an automobilebrake technology that automatically varies the amount of force applied to each of a vehicle's brakes, based on road conditions, speed, loading, etc. Always coupled with anti-lock braking systems, EBD can apply more or less braking pressure to each wheel in order to maximize stopping power whilst maintaining vehicular control. Typically, the front end carries the most weight and EBD distributes less braking pressure to the rear brakes so the rear brakes do not lock up and cause a skid. In some systems, EBD distributes more braking pressure at the rear brakes during initial brake application before the effects of weight transfer become apparent
How ABS works
Under heavy braking, vehicle wheels may lock-up. The anti-lock braking system (ABS) monitors wheel speeds and releases pressure on individual wheel brake lines, rapidly pulsing individual brakes to prevent lock-up. During heavy braking, preventing wheel lock-up helps the driver maintain steering control. Modern ABS has an individual brake line for each of the four wheels, enabling different braking pressure on different road surfaces. For example, less braking pressure is needed to lock a wheel on ice than a wheel which is on bare asphalt. If the left wheels are on asphalt and the right wheels are on ice, during an emergency stop, ABS detects the right wheels about to lock and reduces braking force on the right wheels, helping to avoid lock-up and loss of vehicle control
Operation
The anti-lock brake controller is also known as the CAB (Controller Anti-lock Brake). Typically ABS includes a central electronic control unit (ECU), four wheel speed sensors, and at least two hydraulic valves within the brake hydraulics. The ECU constantly monitors the rotational speed of each wheel; if it detects a wheel rotating significantly slower than the others, a condition indicative of impending wheel lock, it actuates the valves to reduce hydraulic pressure to the brake at the affected wheel, thus reducing the braking force on that wheel; the wheel then turns faster. This process is repeated continuously and can be detected by the driver via brake pedal pulsation. Some anti-lock systems can apply or release braking pressure 15 times per second. If a fault develops in any part of the ABS, a warning light will usually be illuminated on the vehicle instrument panel, and the ABS will be disabled until the fault is rectified.
Modern ABS applies individual brake pressure to all four wheels through a control system of hub-mounted sensors and a dedicated micro-controller
Conclusion
We can reduce the accidents by four wheelers by incorporating these systems