November 2010, TruckingInfo.com - Feature
Trucks are probably the most complex vehicles on the highways today. They fairly bristle with electronic controllers, multiplexed wiring, and sensors.
The proliferation of these components makes troubleshooting ever more a case of obtaining the right tools and software, the suppliers' manuals, fault-trees and repair procedures to sort out fault codes and malfunctions when things go awry.
The latest crop of complexity to come down the pike includes fully integrated safety systems that combine electronic controls for antilock braking systems with controllers that look for vehicle instability, then initiate a response that stabilizes the vehicle and avoids potential accident situations.
Nice when it works, but often a severe pain to troubleshoot when it doesn't.
When truck owners are spec'ing for safety, that includes trucks, truck systems, driver aids and so on. We can also look at it from the perspective of components that improve primary safety, where the accident is made more avoidable, and secondary safety, where the consequences are mitigated. Some technologies span both fields, such as adaptive cruise control with active braking. In many cases this combination can avoid a crash altogether. In the worst case, the active braking will slow the truck so the collision with a second vehicle is at a much slower speed and the crash is much more survivable for all parties.Braking and Stability Control
Bendix and Meritor, both major suppliers of the air and braking systems, are heavily involved in integrating their safety systems into existing ABS platforms. As it develops new technologies, Meritor calls this the Pyramid of Safety Bendix charts it as a building-block progression. Both offer stability control and collision avoidance, and most truck OEMs now offer them either as own-brand original or optional systems available only with a new truck.
Most of the integrated systems are so complex that there is little opportunity for aftermarket sales.
A major exception is a roll stability system retrofit to an ABS-equipped trailer. MeritorWabco has the RSSplus, (Roll Stability Support for trailers) which is basically a stand-alone trailer system.
Since it is fully independent of tractor systems, the company has created an aftermarket product that will integrate with the trailer ABS - including other brands - and provide a significant safety upgrade to a fleet that is looking for a better match of older trailers to sophisticated new tractors. And it even provides stability benefits if the tractor is not equipped with stability control.
Many trailer dealers have been able to upfit their regular customer fleets with this system and report both happy customers and happy finance controllers at their shops.How They Work
While you may not be able to sell most of these systems, you will be seeing them increasingly in the service bay, or need to provide parts for their repair. To even begin to do this, you'll need to understand how these technologies work.
Each is made up of similar elements. The basis is antilock braking and its electronic controls. The addition of an accelerometer makes the ABS into a simple roll monitor and controller; rollover can be prevented by activating braking - first the engine retarder, then service brakes if a truck gets near to a rollover event. The addition of a yaw sensor and steering input sensor adds additional functionality and makes the anti-roll safety system into a stability system that keeps the truck going in the direction determined by the driver's steering by selectively applying brakes.
Service of these systems obviously requires a very thorough grounding in ABS technology, the diagnostics and troubleshooting of the systems and the expertise to fix problems with the base system. Hand-held tools and readers from the component suppliers are likely going to be essential.
Completing the suite of safety building blocks is the addition of radar-based adaptive cruise technology to turn the stability and safety system into a collision-avoidance technology. Adaptive cruise control maintains a consistent following distance courtesy of the radar, regardless of the speed of the vehicle ahead. If the lead vehicle slows abruptly - even down to a dead stop - the system senses an impending accident.
When this happens, the service brakes are applied up to a percentage of full application. The idea is to catch the driver's attention and have the service brakes already applied when he gets harder on the brakes. Even if the truck is going too fast to avoid the crash, it slows significantly before impact, mitigating the consequences.
Both Meritor and Bendix are working on the next component: visual recognition of the situation ahead. Today's radar-based collision avoidance systems need to see the closing speeds and can't recognize the stationary object in all cases. Visual recognition through video will provide an additional safeguard and provide full brake application when needed.
The various components of the full collision safety system can be applied on their own. There is currently a study to evaluate the various benefits each alone provides. Undoubtedly active cruise control is a step in the right direction, as is basic stability control. But when combined into a total system, it could hardly be argued they offer the most benefit.
The response that is generated automatically by these systems will obviously be dependent on the total amount of braking available - the more brake, the shorter the stopping distance. This is set to get a major boost with the reduced heavy truck stopping distances mandated in the latest FMVSS121 standard set to hit in 2012. Theses standards set a 30 percent reduction in stopping distance down from 355 feet to 250 feet for three-axle tractors first, then a year later for two-axle units. The result will be bigger brakes for the front axles, and they will definitely help the collision avoidance in a following vehicle crash.
Whether those brakes will be bigger drums or disc brakes is unclear yet, though disc brakes for the steer axle are being offered in most data books now. Peterbilt has announced that its new 587 will be offered with front discs as standard. Air discs have the advantage of not only pulling up harder with no fade, but there's also no self-energizing that can lead to pulling to one side in a panic stop.
The long and the short of this is that the service workshop is going to see a widely varied set of safety technologies on any particular model of truck. And there may - or may not - be a proliferation of air disc brakes that technicians are going to have to become more familiar with servicing.High-Tech Vision
Another high-tech driving aid that has received rave reviews from industry leaders is lane departure warning. Prime, for example, has seen a 62 percent reduction in lane departure related accident. Steve Williams of Maverick Transportation is a big advocate of the technology; he uses the Iteris product, as do most other fleets that have embraced the technology.
This is a camera-based system that reads the road markings - particularly the white lane marking lines-and issues an audible warning resembling the sound of a rumble strip to grab the driver's attention so he can get the truck back into lane. According to Iteris North American Sales Director Bill Patrolia, this warning can be tied in to the on-board communication system so that if a driver repeatedly strays off the road, dispatch can be alerted.
The latest twist to the integration of safety systems is that the Iteris LDW now talks to Meritor's OnGuard stability and collision avoidance system to give integrated driver reports. This further increases the complexity of the overall package.
While we're talking about vision, aftermarket camera vision systems, such as Voyager from Jensen Heavy Duty, provide a high-tech sol