Many in the industry are now asking the question, “Where’s the innovation in medium duty?” It turns out, though, the real question is, “What’s really driving innovation in medium duty?” For truck manufacturers, the answer to that question is a mix of fleet customer business needs—their need for trucks that are generally used as tools for a specific purpose and to meet ever-present regulatory challenges.
“Working with customers by providing application engineering support is more essential than ever,” Scott Newhouse, chief engineer at Peterbilt Motors Co. , says. “Chassis designs that make for easier upfitting of a wider range of work bodies with things like predrilled holes and electrical connections are important. Customers are increasingly a part of the engineering process, and dealers work with them to spec vehicles as close as possible to their needs.”
A clear frame rail is one example, Newhouse points out. “A clear frame rail package optimizes chassis space to help accommodate installation of bodies,” he says. “Additionally, this configuration can also result in greater ease of serviceability.”
Ramses Banda, product manager, medium duty at International Trucks, also points to custom frame piercing as an important part of medium-duty truck chassis design. “Flexibility is essential for upfitting because in each market segment, it can get complicated quickly when you have to meet unique needs,” he states.
“Electrical system integration is also important,” Banda adds. “The ease with which systems that are designed to maximize operator productivity can be added without making modifications allows for more capability.”
“Freightliner Trucks has a wide range of chassis component configurations that ensure compatibility with any type of body installation,” states Mary Aufdemberg, director of product marketing. “We have updated the routing and clipping of air and electrical lines on the chassis, which contribute to easier upfitting and increased reliability and durability.
“The cleaner installation of these vehicle vitals is also facilitated by a continually improved multiplex architecture. It integrates complex body and truck electronics through a factory-installed solution and simplifies body integration for equipment manufacturers,” Aufdemberg adds.
Kenworth Chief Engineer Kevin Baney says the largest factor driving medium-duty truck design is matching customer needs. “We work with body builders to develop guidelines,” he states. “Our chassis are used in a broad range of applications, so it’s important to have the right chassis and electrical system configurations for all types of customers.”
Frame strength and weight are factors in medium-duty chassis design at Mitsubishi Fuso Truck of America (MFTA), notes Larry Smith, director of fleet operations. “An advanced frame design with patterned holes that make upfitting easier while reducing chassis weight is the goal,” he says. “Frame strength is still quite high, so payload capacity actually increases based on the chassis’ weight reduction.”
“A clean top of frame rail so there is no need to relocate components and wiring that is configured ahead of time are examples of how Isuzu Commercial Truck of America is coordinating with body builders and upfitters,” says Brian Tabel, executive director of marketing. “There is much more coordination. In the past, body builders would configure their products after the truck was designed. Today, that takes place as the cab and chassis is developed.”
Designed for operator ease
Another challenge manufacturers are addressing is that businesses that use medium-duty trucks are not always employing traditional drivers. The use of operators who also serve in sales and service roles makes it important to design trucks that are highly maneuverable, easy to operate and comfortable.
For that reason, manufacturers note, cabover models in particular are increasingly popular in many of these applications. For less experienced drivers, they say, the ability to make tighter turns and added forward visibility are advantages of a COE design.
Productivity and comfort issues are at the top of many design lists. “Cabs have been designed for driver comfort, with high-visibility windshields that allow a view of the street surface far in front of the cab,” MFTA’s Smith explains.
“We’ve seen a greater acceptance from customers of more driver-focused and comfort features such as heated seats, Bluetooth, enhanced telematics, and how the instrument panel is configured,” Freightliner’s Aufdemberg says. “We have observed many customers spec a number of interior options that they otherwise haven’t in the past.”
Kenworth’s Baney notes that medium-duty cab designs are focused on driver comfort, convenience and ease of operation. “In medium-duty operations trucks are tools,” he says, “so fleets want a vehicle that has exceptional maneuverability and visibility, and that drives like a car.”
More car-like
From a medium-duty perspective, points out Peterbilt’s Newhouse, comfort and productivity are very important. “Operators are often delivering products and performing service functions,” he states, “so the focus on innovation is on things like ease of entry and exit and on a simplified, auto-like interior so there’s less stress and an easier transition for drivers.
“The focus going forward is on productivity and connectivity,” Newhouse says. “We’ve made available on select models real-time visual messaging and an in-dash system that features an array of virtual gauges, auto-activated safety cameras, hands-free calling, and the capability to provide traffic and navigation information.”
Medium-duty trucks are also following a heavy-duty trend by including more information for drivers, and they are being engineered to provide higher levels of safety. Systems usually associated with heavy-duty trucks are also finding their way into medium-duty models, notes International’s Banda, who points out a growing desire for things like collision avoidance systems.
When it comes to stability control solutions, Newhouse agrees and adds that items like disc brakes are popular among medium-duty operators for their stopping power and car-like feel.
“While active safety systems have been around for awhile in on-highway vehicles,” says Aufdemberg, “active safety technology will continue to make its way into medium-duty and vocational applications.”
The latest powertrains that are at the heart of all medium-duty truck models are being designed to address the impact of fuel efficiency and greenhouse gas (GHG) emissions standards. Fuel economy and GHG standards are already in effect for model years 2014 to 2018, and tighter requirements for model years after 2018 are due to be proposed by the Environmental Protection Agency and the National Highway Traffic Safety Administration this year.
“We’re looking at different strategies to meet greenhouse gas emissions and fuel economy standards,” says Glenn Ellis, vice president of marketing, dealer operations and product planning at Hino Trucks. “Telematics will play a key role in meeting those standards. We also believe fleets will see more parallel hybrid systems and electrically driven auxiliary systems, such as water and fuel pumps, to allow engines to be more fuel-efficient.
Slow adoption of natural gas
“It also looks like natural gas will continue to struggle to find a place in the medium-duty market,” Ellis continues. “In light-duty applications, you can convert a gasoline engine to a natural gas engine at a relatively affordable price. In Class 8 trucks, because of the amount of miles run annually, you can achieve a payback. In medium duty, however, you still have a large technology premium but do not generate the miles to achieve a short-term payback. There’s also the issue of natural gas fuel tanks interfering with body applications.”
“Most fuel efficiency innovations have applied first to heavy-duty linehaul trucks,” states Freightliner’s Aufdemberg. “In those vehicles, they present an opportunity for improvement that is not always easy to apply to the medium-duty market with its many different applications and duty cycles.
“Downspeeding, for example, improves fuel efficiency by lowering engine rpm at highway speeds in top gear,” Aufdemberg explains further. “That concept, however, loses its effectiveness on an urban delivery or utility truck that spends far more time accelerating through gears, stopping and going, or idling. Medium-duty engines must be efficient throughout the rpm range and take full advantage of technology like high pressure fuel injection and opportunities to reduce parasitic accessories.”
International’s Banda says diesel engines are still overwhelmingly chosen for medium-duty models for their reliability and predictable maintenance needs. MFTA’s Smith notes that the company introduced lower displacement diesel engines in 2012 medium-duty trucks. While it continues to refine those powerplants, it is also exploring the use of hybrid and natural gas–fueled engines.
Tabel says Isuzu engine design is continuing to evolve as the industry gets more clarification on future fuel economy and GHG standards. The company’s diesel-powered models for 2016 already meet the latest requirements, he notes, and the OEM offers both CNG and LPG conversion options for its gasoline engine through outside suppliers.
Going automatic
To improve driveability in medium-duty trucks, manufacturers are providing fully automatic transmissions, which offer smooth engagement and torque transfer capabilities that are ideal for operating in stop-and-go applications consistently and accelerate through gears more often. A number of OEMs also point to Allison’s FuelSense technology for the company’s fully automatic transmissions as a part of their fuel efficiency improvements. FuelSense automatically adapts shift schedules and torque to maximize transmission efficiency based on load, grade and duty cycle.
Automated transmissions, which have made great strides in the past few years in heavy-duty trucks, are also seen as being able to provide a benefit in medium-duty vehicles. Scheduled to be available in the middle of this year are new Eaton Procision medium-duty dual clutch transmissions. The 7-speed transmissions feature electronic shifting that uses grade, vehicle weight and throttle input to provide optimal fuel efficiency and smooth, continuous delivery of torque to a vehicle’s wheels under all shift conditions.
“Eaton employed dual clutch technology to allow for more efficient acceleration from a stopped position, and to optimize shift points in a way that will most efficiently get to the highest gear,” explains Jeff Carpenter, engineering manager, medium-duty Procision. “Gear changes are made by swapping the engine torque between clutches and preselecting the next gear so the closed-loop control system reduces slip and steady state losses.”
Features such as Eaton Dynamic Shifting allow the Procision transmission to automatically switch between economy and performance shift schedules. The shift schedules are modified dynamically based on available torque, engine acceleration, weight and grade. Economy and performance shift tables can also be adjusted to tune an overall calibration to meet any customer’s specific needs.
Focus on cost of ownership
While medium-duty truck manufacturers are focused on designing vehicles to meet a range of applications and needs, the OEMs also say that fleet customers are not driven only by price. Instead, they are willing to pay a premium for a vehicle they know will ultimately help contribute more to the bottom line.
“Medium-duty customers are thinking more about cost of ownership,” says Freightliner’s Aufdemberg. “They’re considering what they need in a vehicle to get the job done, how to optimize the balance between performance and economy, what features are most important to their businesses as well as their drivers, and what the product will do to help them run a smarter business throughout the lifecycle of the vehicle.”