Brakes of the Future

Electronic controlled braking systems (ECBS) will be the brakes of the future — no question about it. But there are some differences of opinion as to exactly when this will happen.

Some fleet managers, including those in waste collection and recycling, believe that within three years, regulators will introduce new brake performance standards that will mandate using ECBS and air disc technology.

On the other hand, braking system consultant Dick Radlinski of Radlinski & Associates Inc., East Liberty, Ohio, believes that using ECBS will not be widespread for at least 10 years. He also thinks that the government would have a hard time writing new standards for the systems until their safety aspects are proven. This will be relatively difficult to do in the short- or medium-term, he says.

Others industry watchers remember the fiasco in the early 1970s when U.S. regulators tried to legislate anti-lock braking systems (ABS) before they were perfected. This time, they believe the government will act more slowly.

These super-high-tech stopping systems, also called brake-by-wire or electronic braking systems (EBS), all mean the same thing: air no longer will trigger brake applications; electrical signals will.

In addition, many manufacturers are planning to co-produce air disc brakes for Class 8 tractors and trailers along with ECBS, with the promise of high-fade resistance, superior stopping and remarkable stability over S-cam systems. And, disc brake manufacturers say features of disc brakes offer external wear indicators to make inspections simple and reduce the possibility of rotor damage due to excessively worn linings. Maintenance and vehicle downtime would be reduced as well, because only the tire and wheel assembly need to be removed to change lining pads.

To keep fleet managers current on the technology — and to prepare for the inevitable — The Maintenance Council (TMC), Alexandria, Va., devoted one day of its October meeting to the subject of ECBS.

First, a technical session was followed by an all-day program at National Highway Transportation Safety Administration's (NHTSA) Vehicle Research Test Facility (also called the Transportation Research Center), East Liberty, Ohio. The program consisted of live demonstrations of various braking scenarios and brake-testing equipment.

Radlinski opened the tech session by explaining the basics of EBS:

  • Electronic control replaces pneumatic control;
  • Wires replace air control lines;
  • Air can be the backup;
  • Air still actuates brakes;
  • EBS provides the antilock function; and
  • EBS can provide a whole range of new functions.

“EBS is a platform for brake balance control, smart cruise control, stability control, rollover prevention and self-diagnosing brakes,” Radlinski said.

The potential advantages, he continued, include:

  • Economic benefits — Improved brake wear, less downtime, reduced tire wear and self-diagnosis;

  • Safety — Shorter stops, better brake balance, improved stability/control and reduced rollover;

  • Diagnostics — EBS can measure foundation brake performance and quickly identify problem wheel ends and maintenance requirements; and

  • Driver Comfort — The relationship between pedal feel and pedal force v.s deceleration is improved and constant, regardless of loading.

The EBSs currently available are “the first step,” but they need to be simplified, Radlinski said.

“Reliability needs to be proven, costs must be reduced and more sensors and functions need to be integrated,” he added. “For example, current sensors include wheel speeds [vehicle speeds, deceleration, tire slip] and pressures [brake inputs]. On the other hand, future sensors will include brake temperatures, brake torques, axle loads and steering wheel angle, [as well as] vehicle yaw rate and lateral acceleration.”

According to Radlinski, drawbacks to current EBSs include complexity, weight and the cost vs. the benefits.