Big changes in big trucks have slowed, but ongoing incremental improvements are still yielding big benefits.
Advances include electronic safety features such as collision mitigation and lane departure warning. Steering has been made easier to reduce driver fatigue. Customers also have more say in the configuration of the chassis and the body, allowing for a more customized hauler to meet their specific work needs.
Advanced electronics, such as Bendix Wingman Fusion, are enhancing safety. The latest iteration of the Wingman product integrates radar, video and braking (hence the “Fusion” name). Features include collision mitigation, electronic vehicle stability control, lane departure warning, adaptive cruise control and a variety of alerts, including for overspeed and insufficient following distance.
Some manufacturers offer the Bendix solution; others provide their own. These systems may be either standard or optional. For example, collision mitigation is standard on the Peterbilt 579 tractor and optional on its 567 vocational truck. Traction control and stability control are standard features on both.
Limitations exist for these safety features. Drivers must see them as assistance and not be overly reliant on them for detecting hazardous conditions and announcing timely notifications.
For example, if the driver changes lanes to avoid an impact, some programs update their algorithm based on the new lane position but some do not. Non-metallic objects – wildlife, livestock, tree limbs, pedestrians – may not be detected. Vehicles not oriented in line with the traffic lane may slow the system’s response.
Another safety system comes from Lytx, which offers cloud-based monitoring using cameras and sensors. Its 360-degree dash cams can deliver up to 100 hours of video for driver training and crash investigations. GPS provides fleet tracking. And Lytx satisfies the requirement for an electronic logging device (ELD).
Mack offers a pre-wire option for the Lytx video telematics system. Mack also has its own Over The Air (OTA) remote programming. This allows remote software updates and the setting of vehicle parameters via Mack GuardDog Connect hardware. Approved personnel, including drivers, can initiate the process through the instrument cluster.
Tony Sablar, vocational product manager, Class 8, Peterbilt, points out how OEMs provide certain electronic safety features that are triggered by the truck body. “We have multiple programmable interlocks,” he says. “If the driver’s door is opened without the parking brake being set, the horn sounds. Travel speed may be limited to 5 mph if the dump body is raised. PTO engagement requires that the truck be in neutral with the parking brake set.”
The new Western Star 49X has pre-wired, sealed connectors on the back of the cab, a dash port with integrated RP1226 connector and a flex plate in the dash for easy back-of-dash access and for convenient mounting of upfitter gauges and switches.
Steering is a major contributor to driver fatigue, so manufacturers are finding ways to make it easier. Mack Command Steer, available on Granite axle back models, uses electric motor assist to reduce steering effort by up to 85 percent.
Volvo Dynamic Steering uses torque assist to minimize movement of the steering wheel caused by variations in road surfaces. It also compensates for road crown and crosswinds to help the driver maintain directional stability.
The availability of twin-steer trucks is expanding. The twin-steer design’s use of two front axles provides greater load capacity and distributes weight better, which comes in handy where local bridge laws are a limiting factor.
Kenworth introduced the T880 Twin Steer with back set front axles at ConExpo 2020. Available as a day cab, the model is “ideal for crane, mixer and other vocational applications that require 86-inch axle spacing in certain environments,” says Laura Bloch, Kenworth assistant general manager for sales and marketing. Standard features include aluminum fenders over the second axle and step-between axles for cab access. Front suspension is equalized between the two steer axles.
The T880 Twin Steer is available with the PACCAR MX-13 engine with up to 510 horsepower and 1,850 pound-feet of torque, or the MX-11 engine with up to 430 horsepower and 1,650 pound-feet of torque. Standard configuration is a 116.7-inch BBC short hood optimized for MX engine use. A 122.6-inch BBC standard hood is an option for use with the MX-13 and optional Cummins X15 engines.
Also in 2020, Kenworth brought the improved PACCAR 12-speed automated transmission to the T880. The transmission’s shift parameters were optimized for use with the PACCAR MX engine family to enhance performance. More aggressive clutch engagement provides faster full-throttle launches. Upshift points are higher under full throttle acceleration, and downshifting occurs sooner to help maintain constant speed on grades and high-resistance surfaces. “The enhanced PACCAR transmission is intended for use on T880s that travel mainly on paved roads with occasional operation on maintained dirt or gravel roads,” says Bloch.
In an emergency-braking event, the Volvo VHD transmission can skip downshift to maximize the effectiveness of engine braking. Other features of the VHD include a spacious cab, nearly 7 feet wide and over 5 feet high from floor to ceiling, standard LED headlights with optional heater to improve performance in cold conditions, up to two factory-installed lift axles and an optional twin-steer preparation package. The VHD is Volvo Trucks’ model for vocational markets and is available as a truck or tractor in axle-back and axle-forward configurations. A 42-inch integral sleeper is also available.
Standard suspension on the VHD is Volvo’s T-Ride system. An Extra Firm variant with ratings of 44,000 to 46,000 pounds is now available. This upgrade increases roll stiffness while retaining the T-Ride’s 17 inches of articulation.
“Extra Firm is for applications with high centers of gravity, such as mixers and vacuum trucks,” says Andy Hanson, product marketing manager, Volvo Trucks North America. “Notably, the Extra Firm T-Ride is 200 pounds lighter than a comparable walking-beam suspension, allowing for more payload in weight-sensitive applications.”
OEMS have also brought out advancements that don’t carry the high-tech wow factor, yet carry substantial benefits.
Peterbilt uses bright yellow grab handles and offers optional orange seatbelts to enhance safety.
Volvo offers a recessed center tow pin rated at 80,000 pounds that retains the VHD’s 113.6-inch BBC dimension. “Center tow pins are the preferred means for pulling trucks on construction sites since they reduce the likelihood of applying uneven loads to the frame,” says Hanson.
Western Star uses topology optimization, a design technology, to create the steel reinforced aluminum cab of the 49X. The back of the cab is clear to facilitate body installation. The top of the cab is slightly higher above the doors. The lower center roof provides clearance for accessories such as lights and horns, while the raised ends help ensure easy access to the cab.
Some manufacturers, like Mack and Volvo, stress the value of an integrated drivetrain made up entirely of OEM components. Others insist peak performance is attained by using components from manufacturers specializing in those components, be it engines, transmissions or axles. Both make compelling cases. For customers, the decision often comes down to what their preferred dealer offers.
Western Star tries to have something for everyone with the 49X. It offers a Cummins X12 with up to 605 horsepower. But the primary power choices are Detroit Diesel DD15 with up to 505 horsepower and DD16 with up to 600 horsepower. There are three drive modes: Econ for normal highway use, Performance with more aggressive shift points and Off-Road for the most aggressive performance. (Western Star and Detroit both are part of Daimler Trucks North America.)
Both transmission choices for the 49X are vocational models from Detroit: the DT12-V for up to 2,050 pound-feet of torque and the DT12-VX extreme duty rated for up to 2,500 pound-feet.
Transmission features include hill hold and power launch for heavy starts. Rock Out engages and disengages the clutch to provide a rocking motion to help free a stuck truck. Paver Mode permits shifting from neutral (when being pushed by a paver) to drive (when pulling away with an empty dump body) without stopping first. This eliminates potential ripples in the asphalt at the stopping point.
Chassis and body integration
The other area of integration is between the chassis and the body. Sablar says this falls into two main areas: mechanical and electrical.
Examples of mechanical integration include working with the body builder regarding clearances, centers of gravity and the placement of lift axles, air tanks, diesel exhaust fluid tanks and air driers. Remote throttle control is a common example of electrical integration.
Customers contribute to this integration effort by developing a clear idea of what they want their trucks to do. “Vocational trucks solve a problem,” says Sablar. “We help customers spec the best tool for their needs.” He says the dealer sales representative serves as liaison between the customer, the OEM and the body builder, “although Peterbilt also works directly with body builders to ensure integration.”
The Mack Body Builder Support Team helps streamline the body selection and upfit process and provides customer support before, during and after a truck sale. Mack’s online Body Builder Portal helps customers visualize and spec their ideal truck.
Kenworth offers an optional DEF tank with integrated steps. Placing the access steps to the deck plate over the tank frees up as much as 16 inches of frame space on the T680 tractor and T880 vocational truck. The option uses Kenworth’s 21-gallon, medium-size aerodynamic DEF tanks and is not compatible with full or partial chassis fairings.
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