Imagine you're driving down the highway at 50 miles per hour (80.5 kilometers per hour) and you see an obstacle in front of you -- a stopped car, for instance. You step on your brakes but there isn't room to come to a full stop before you collide with the car's rear bumper. In desperation you turn the steering wheel to one side to go around the stopped car, even while you're still pressing down on the brake.
What happens? Well, if your car has a traditional braking system, you might be out of luck. The shifting vehicle weight can cause the tires to lock, which reduces your ability to steer. You may find that you can't get around the obstacle in time. Or the car may oversteer and go out of control. With electronic brake force distribution, on the other hand, your vehicle's tires don't lock up and you retain the ability to steer. And the oversteer is prevented by maintaining the proper brake force to the inner and outer wheels. As a result, you're more likely to get out of this situation with your car intact and your passengers uninjured.
Now imagine that you're driving on an icy surface or a road slick with rainwater. Under these conditions it's really easy for your car to go into a skid. And although EBD cannot detect road conditions directly, it can deduce them from the slip ratio of the wheels and compensate accordingly. If conditions are different for each wheel -- for instance, if one wheel is on a patch of ice and the other is not -- this can be detected through the slip ratio. Although there's no magic solution to the problem of stopping a car under bad road conditions, EBD can make emergency braking under these conditions as safe as possible.
Here's another less-than-obvious benefit of EBD: When you load the trunk of your car with luggage, it changes the traction on your rear wheels, which means that more force can be applied to these wheels during braking. A standard proportioning valve wouldn't necessarily take this extra weight into account, but electronic brake distribution compensates appropriately for your car's now heavier rear end. EBD can't detect this extra weight directly, but the system becomes aware of it through its effect on the slip ratio of the tires.
To state the obvious, driving safely is important to everyone -- even pedestrians. Electronic brake distribution and antilock brake system technology, especially when coupled with other safety technologies such as traction control and electronic stability control, is a major contribution to driving safety and can help keep you and your family safe, whether on long trips or just a drive to the local grocery.
To learn more about safety and regulatory devices and other related topics, follow the links below.
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- Carley, Larry. "Electronic Brake Distribution: Emerging Technology Offers Service Opportunities." Import Car. Feb. 1, 2009. (Nov. 3, 2009)http://www.import-car.com/Article/46362/Electronic.aspx
- Ribbens, William B. "Understanding Automotive Electronics." Sixth Edition. 2003. Elsevier Science. Burlington, Mass.