TRUCK TRACKS

Choice for brakes isn't automatic

Article December 28, 2000
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Electronic controls are taking over brake systems


Electronic controls are taking over brake systems. In fact, when viewed as complete systems, the electronic parts (EBS) can be seen as leading a general swing to wider use of sophisticated safety features on big vehicles today. In the procress, they are reducing the role of the more familiar hydraulic and pneumatic brake controls.


The current swing to electronics did not start with brake controls. But, as in other vehicle systems, reliance on electronic brake controls is on the rise because those parts are generally smaller, lighter, more reliable, work faster and require less service than their competition.


EBS controls do have to overcome drawbacks headed by higher initial cost and lack of familiarity in the field.


Electronic braking systems start with a wire running from the driver’s brake pedal to a vehicle’s brakes. Simplification goes out the window when the wire reaches the foundation brakes. In addition to normal brake control, EBS goes on to manage any antilock feature and any traction control ability in the vehicle’s braking system to deliver total control of the system.


When antilock brakes were required by federal regulators on truck and trailer air brakes, air actuated controls were deemed the only ones strong enough to apply them.


Even though current air brakes with antilock capability lack some of the features of full-blown EBS systems, one expert in the antilock field was able to tick off this list of benefits which the systems do deliver:


  • Improved dynamic force distribution;

  • Shorter stopping distances (improved timing);

  • Improved balance of front to rear axle brake lining wear;

  • Improved tractor-trailer brake balance;

  • Brake fade warning and;

  • Self diagnosis and continuous monitoring.

Some brake experts have expressed hope that federal regulators will, in time, eliminate current rules that require use of air brake parts in conjunction with the EBS system to comply with Federal Motor Vehicle Safety Standard 121.


In addition to working for elimination of required duplicate parts, experts in the brake field are looking to advance the compatibility of tractors and trailers, when used in combinations, and taking further steps to reduce the cost of antilock systems.


Only the best will do


Recognition of the EBS standing among truck safety systems could be clearly seen in Eaton Corp.’s recent addition of that system to features of the firm’s Innovation Truck, which was developed as a showcase for the best in truck safety hardware.


At the same time, the Dana Spicer organization, which is working with Eaton on the demonstration vehicle, added other advanced component to the showpiece, Dana Spicer Air Disc Brakes.


Like antilock brakes, air disc brakes have been more widely used in Europe than in the U.S. Air discs from Dana Spicer are scheduled to go into production for North American markets early in 2000.


An abbreviated list of safety features being demonstrated on the Innovation Truck includes Eaton Fuller AutoShift transmissions, a Dana Spicer tire management system, the Eaton-VORAD radar-assisted braking and cruise control systems, as well as a setup for looking into blind spots around heavy vehicles.


Electronic Stability Control (ESC) is being advanced by industry experts beyond Eaton-Dana as the step to follow EBS and Automatic Traction Control. Both of the latter apply to controlling longitudinal movement during braking and acceleration.


ESC extends the EBS functions with additional sensors and algorithms to provide protection against loss of control due to rotational forces resulting from rapid lane change or cornering maneuvers.


By adding sensors and appropriate algorithms, EBS is said to enable selective application of individual brakes.


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