There's no hesitation when Alan Korn is asked to name the technology that has his team of engineers excited these days — EBS, or electronic braking systems. “It will add a lot of capability to current brake systems both near term and further out,” says Korn, who is the chief engineer of Meritor WABCO, the North American brake control joint venture between automotive component manufacturer ArvinMeritor and European brake specialist WABCO.
Commercially available in Europe since 1994, EBS is already being run in limited numbers in North America on a demonstration basis, and wider availability is “very close,” says Korn. In the first phase, EBS will deliver better brake balance and quicker stopping times, especially with tractor-trailer combinations. Replacing air control valves and lines with electronics “will add a degree of intelligence to braking systems, just like we saw with electronic controls for engines and transmissions,” he says. “Essentially, a driver tells the [EBS] how fast to stop, and the system decides how best to accomplish what the driver wants.”
Further out, such a brake-by-wire system “provides a good platform for even more advanced technologies, especially active braking,” Korn believes. Today's antilock braking systems (ABS) already employ active braking in a limited fashion to provide traction control, applying brake pressure to a spinning wheel without any input from the driver.
EBS could expand that concept to provide improved safety and driver convenience “because it can control braking independently at each wheel,” says Korn. For example, such a smart system might offer advanced stability control for tractor-trailer combinations, automatically applying brakes at various wheels in an emergency situation in an effort to regain vehicle stability.
“You have to be careful with a system that actively controls brakes without the driver stepping on the pedal, so we're moving cautiously,” says Korn. “But I think you'll see it with adaptive cruise control fairly soon.”
Korn believes that air disc brakes will also find their way onto North American heavy-duty trucks in the not-too-distant future (for more on air discs, see Brake feature, page 55). “You don't have to couple EBS and air discs, but tying the two together gives you the most efficient brake system,” he explains. “Discs can generate a lot of torque, and EBS is a good manager of torque.”
Adding advanced electronics to the brake system will also bring advantages to the trailer, Korn believes. The industry has recently adopted a multiplexing communications standard called PLC4Trucks that allows information to pass between tractor and trailer over the standard 7-pin connector and ABS controllers. Currently, the system is only being used to send a trailer ABS warning signal to the tractor's dash, “but it's a good gateway for new trailer electronic architecture,” Korn points out. “With the protocol established, you'll see more and more features flowing to electronics on the trailer for advanced systems like active suspension control.”
Advanced brake electronics will also bring new diagnostic capabilities. “Our current ABS are already compatible with most diagnostic tools, and we have PC-based diagnostic systems in product development,” Korn says. “EBS will have the intelligence for self-diagnostics and even predictive diagnostics.”
Just as electronics have linked engines and transmissions for major improvements in performance and productivity, Korn sees intelligent controls soon bringing similar improvements to brake systems as they tie them more closely to advanced suspension systems. “Given ArvinMeritor's hardware expertise in brakes and suspensions, and ours in brake control electronics, we're in a good position to take advantage of that combination,” he says. “And, clearly, that's the direction we're moving in.”
Each month this column will look at emerging truck technology issues through the eyes of some of the industry's leading engineers.
Name: Alan Korn, chief engineer, Meritor Wabco Vehicle Control Systems
Background: Graduated from Lawrence Technological University with a bachelor's degree in mechanical engineering. Joined Rockwell Corp. (now ArvinMeritor) in 1985 after working on automotive and truck foundation brakes for Kelsey Hayes and Lucas Industries. Moved to Meritor WABCO in 1990. Currently active in both TMC and SAE.