Dennis Losh, Director of engineering
Kevin Romanchok, ABS product line director
Bendix Commercial Vehicle Systems LLC
We believe there is no driving need in terms of vehicle performance that would require switching to an EBS (electronic braking system) solution,” says Dennis Losh, director of engineering for Bendix. “Nonetheless, ‘EBS is coming!’ has become a very popular topic.”
Maybe that's because people, even jaded trucking types, can't help but get excited over even unproven gee-whizzy gizmos. The idea of braking without wires certainly fits that bill.
Getting back to brass tacks, Losh states unequivocally that “EBS has no significant advantage over an ABS (antilock braking system) supplemented by advanced features providing electronic roll stability.”
ABS is itself an electronic system. Thus, according to Losh, it can serve as a platform for bringing additional advanced braking features to trucks without necessitating a whole-hog shift to full-blown EBS.
“If you look at the history of electronic braking in Europe,” says Kevin Romanchok, product line director for ABS at Bendix, “you'll see that regulations based on the air systems in use for their cabover configurations resulted in a very complex system by the late '80s, one with electrical and pneumatic lines. So there wound up being a value proposition that made using electronics to reduce complexity attractive.
“Over here,” he continues, “we are moving toward electronic features but we're starting with a different vehicle configuration and less complexity. Adding full electronic controls on top of pneumatic ones would increase the cost of the braking system in this market.”
What's important to bear in mind, says Romanchok, is that some features that are becoming feasible with ABS alone, most notably roll control, were seen for years as only possible if the industry were to adopt full-blown EBS.
“But,” Romanchok stresses, “an ABS system can be 'pushed' for greater functionality” without the higher cost and greater complexity that EBS would entail.
“What we feel we've arrived at,” says Losh, “is a pneumatic system solution that offers multiple benefits to OEMs. They can offer a traditional braking system with ABS to those who want just that. Or they can add sensors and valves to scale the system up to provide stability control without changing what's familiar now to fleets.”
There has been discussion in the industry that full electronic braking might be needed to attain shorter stopping distances, long viewed as on the regulatory horizon.
However, Losh and Romanchok argue that EBS would only provide a 2-3% improvement in stopping distances over the current braking systems used by most North American fleets.
Losh says terminology can be a trip wire. “We like to speak of advanced ABS or ABS with added features so buyers understand the basic ABS remains the same.”
According to Romanchok, Bendix's RSP (Roll Stability Program) and ESP (Electronic Stability Program), which will be marketed as additions to Bendix ABS, will be released in “the '04 to '05 timeframe.”
“We expect fleets will select these enhancements based on their operations,” says Losh. “Some fleets, such as those who stay down South, may only need RSP for rollover protection while others will opt for ESP.”
Romanchok explains that RSP is designed to help avoid rollovers by engaging all brakes on dry, high-friction surfaces, such as are encountered coming off exit ramps or when making quick lane changes to avoid obstacles. ESP provides that protection but also handles low coefficient surfaces — meaning ice — when it would engage brakes at individual wheels to help prevent rollovers.
Besides being less complex than an EBS system, perhaps the key message Bendix wants to get out about these upcoming braking enhancements, according to Romanchok, is that “driving is done the same. The system is there to supplement or aid the driver in certain situations. It is fairly transparent,” he adds. “And that is a big benefit of having it ABS-based.”
With these types of enhanced systems in play, Losh envisions pneumatic brakes with ABS “existing for years to come” as the preferred braking setup for North American commercial vehicles.
