Trucks: Technology marches onward
| May 28, 2009 |
Mack standardizes stability protection on Pinnacle models
Onboard electronic systems have revolutionized a multitude of vehicle control and diagnostic systems. And now Mack Trucks is using computer technology to reduce the risk of vehicle rollovers in on-highway tanker and mixer applications with the addition of its Road Stability Advantage (RSA) system, designed in conjunction with, and manufactured, by Bendix.
The RSA system will now be offered as standard equipment on 2008 Mack Pinnacle and Pinnacle axle forward tractors equipped with air ride suspensions. In addition, Mack plans to make RSA standard on the relatively small number of highway vehicles it produces with mechanical (spring) rear suspensions. Current plans are to have that effort by the third quarter of next year.
Tankers and mixers are especially prone to rollover accidents thanks to shifting loads suddenly altering the truck’s center of gravity. To combat this, Mack and Bendix engineers created RSA to be a full electronic stability system, early versions of which were shown to journalists at World of Concrete last January. The simplest way to describe RSA is as an electronic sentinel: the system is programmed to constantly monitor crucial vehicle performance indicators such as ABS wheel sensors, steering yaw and lateral acceleration inputs, and compares them with safe-operation algorithms. If the numbers don’t match – if the lateral acceleration numbers suddenly surpass the system’s maximum acceptable limit, for example – the system springs into action and overrides driver control to deactivate the truck’s throttle and selectively apply the brakes. In sharp curves, sudden lane changes or emergency avoidance maneuvers – the conditions that put a truck at the highest risk for a rollover accident – the system works instantaneously to provide the driver with a more controllable truck and greatly reduces the chance of a rollover occurring.
“The decision to make Mack RSA standing now was not a difficult one,” says Tom Kelly, Mack vice president of marketing. “The system has demonstrated that it can do what it’s intended to do and has been well received by our customers.”
Peterbilt unveils hybrid technology
Peterbilt Trucks will offer a limited production Class 7 Model 335 featuring hybrid-electric technology in 2007, the company has announced. The truck – outfitted with a fully-integrated, Terex bucket lift body with 55-foot aerial boom – is designed for utility and municipal applications and uses a parallel hybrid system developed by Eaton to reduce fuel use.
“There is an increasingly strong demand for hybrid vehicles as customers recognize the bottom-line benefits of reduced fuel use and service requirements, as well as the civic impact of responsible environmental practices,” says Dan Sobic, Peterbilt general manager and PACCAR vice president. To that end, Sobic adds, “Peterbilt and PACCAR are on the forefront of developing hybrid vehicle technologies that benefit both customers and the environment.”
The hybrid Model 335 is powered by PACCAR’s 2007 EPA-certified PX-6 diesel engine. The engine is paired with a parallel hybrid system that uses an electric motor to assist it with supplemental torque for improved fuel economy. The system stores energy through regenerative braking (which stores the kinetic energy generated by physical act of stopping the truck) and reuses it during the take-off phase of the vehicle’s acceleration curve. The system also stores energy when the truck is idling and reuses it to power the truck PTO. The system’s onboard battery can also be used to power the aerial boom without idling the engine.
“We expect the hybrid Model 335 will give operators a 30 to 40 percent reduction in fuel use through the combined improvement of on-road-fuel economy and stationary jobsite operation,” says Landon Sproull, chief engineer for Peterbilt. “These fuel savings are combined with reduced maintenance requirements resulting from less wear on the engine. This is because its workload is supplemented by the electric motor. The truck’s brakes can also be expected to last longer since regenerative braking system helps retard the motion of the vehicle.”
When using the aerial boom, Sproull notes that a J1939 digital controller acts as an interface allowing the truck and the utility body to communicate. This controller senses hydraulic demands from the body during work operations and automatically engages the hybrid system to supply power. Under a full charge, the PTO can operate for approximately 25 minutes before the battery charge becomes low. At that point, the system automatically starts the diesel engine in order to recharge the onboard battery. “It takes about three minutes to fully recharge the battery,” Sproull notes. “So during eight hours of work, the diesel engine will run for less than an hour.”