November-December 2008

The Future of Fleet Specs

In the face of escalating prices, technological advances, and stringent emissions regulations, the refuse industry considers specifications to ensure fuel efficiency without sacrificing performance.

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Photo: Heil Alternative fuels like compressed natural gas can drive down costs and emissions.

By Lori Lovely

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He’s not surprised. He considers the primary concerns in the industry are fuel consumption and productivity. The Curotto-Can, he says, consumes less energy to run a container than in a typical auto truck, chiefly because most of the work is done close to the ground. That means smaller cylinders and lower hydraulic flow requirements. Tire wear, fuel, and maintenance are comparable with any Class 8 truck. “Any truck with an arm behind the driver is old technology,” Kennedy boldly states, noting that the maneuverable front arm helps reduce accidents.

A million things can reduce the cost of operation, Swertfeger believes: quality, reliability, and preventative maintenance are key factors. “You need to understand the life of a product,” he admonishes. His suggested strategy combines purchasing the right vehicles and then providing the best quality replacement parts to meet or exceed the specifications of the original equipment manufacturer. That’s important, because the refuse industry has the toughest duty cycle of any market. “Whoever can pick, pack, and dump consistently with the lowest overall operating cost wins.”

Dependability is Cummins’ answer to Swertfeger’s call for reducing the cost of operation. Nycx credits an in-house combustion fuel system, air handling, and after-treatment for dependable performance. “Our advantage is that all systems (air intake to exhaust) are produced in-house. We design with that in mind: It helps.”

Photo: Heil
Heil's Operate-At-Idle is standard on all automatic side-loaders and operational on other rear-, front-, and side-loaders.
As Cummins’ current production line evolves, expect comparable fuel economy and the same maintenance intervals, Nycx promises. “Performance and lowest operating cost are important.” When the ISX is introduced as a 15-L engine (as the platform is expanded from 11.9 L to 16 L), the power range and power density will be maintained and the horsepower range will be expanded.

Play It Again: Regenerist Systems
When it comes to costs, Hagerstown, IN–based Autocar, North America’s oldest truck manufacturer, keeps a close eye on the price of commodities. “We track the indices of commodities,” Vatter explains. “If commodities keep increasing, we could be building at a loss. We have to pass on temporary inflation adjustments because it costs more to build.” Although sales of Autocar’s Xpeditor trucks have doubled in the last two years, the century-old Class 8 truck builder explains uncontrollable costs (commodities in raw materials and other costs associated with the process) have outstripped its ability to offset them through lean initiatives. In the first quarter of 2008, the indices that track Autocar’s uncontrollable costs have increased by more than they did for the entire prior year.

While Autocar has had to pass along some costs to its customers, the manufacturer is trying to help those customers recoup the expense through efficient equipment. The E3 Xpeditor, powered by an innovative hybrid-drive system developed by Parker-Hannifin, is a “big deal,” Vatter says. Not for sale yet, the revolutionary prototype’s Cummins engine will offer fuel savings up to 50%.

The integrated series hydraulic hybrid overcomes the electric hybrid’s challenge of weight neutrality, as well as its limited hauling capacity, because there are no batteries to store. As Vatter mentions, weight neutrality significantly increases brake life—another cost savings. Hydraulic hybrids capture the energy of a truck stopping and store it in accumulators. Non-compressible hydraulic fluid is held under pressure by a spring, raised weight, or compressed gas. During normal driving, the system is not active; under braking, the system kicks in. The energy is reused to start moving instead of using the engine to turn. In essence, says Vatter, the engine is a generator.

He estimates 70% efficiency, with 70% energy recovered as pressurized oil. “Energy at 500 pounds per square inch is ready to be reused, delivered through HLA. It adds 175 horsepower just using brake—not engine—power and has good torque. It’s a fast truck, with fuel savings in economy mode. In the other mode, it offers quicker productivity enhancement so you can add stops.”

The downside, he says, is its cost and a slow rate of adoption. However, the high cost of diesel makes the payback better, which assists sales. Another drawback, however, is that most people think of electric, not hydraulic, hybrid systems. Vatter complains that they’re not getting legislative help: Federal help given for buying hybrids isn’t extended to hydraulic systems.

Yet another disadvantage is the 1,020 pounds added to the truck. “We’re working on reducing weight by going to a composite instead of a steel accumulator—that will save 200 pounds,” Vatter says, adding that operators say they don’t feel the extra weight, and because they see fuel savings of 10% to15% they’re happy now. 

Manufacturers must explore opportunities to recover wasted energy. “Waste management companies average $92 million per month in fuel costs. Fleet managers have to look at long-term operating costs,” states Robert Golin, senior product manager for Eaton Advanced Technologies and System in Eden Prairie, MN.

Regenerist systems capture previously wasted energy on electric or hydraulic systems. Recovered energy is stored and used to supplement the engine’s power during acceleration, on demand. The system is most beneficial in stop-and-go driving situations. During braking, the vehicle’s kinetic energy drives the pump/motor as a pump, transferring hydraulic fluid from the low-pressure reservoir to the high-pressure accumulator. The fluid compresses nitrogen gas in the accumulator and pressurizes the system. During acceleration, fluid in the high-pressure accumulator is metered out to drive the pump/motor as a motor. The system propels the vehicle by transmitting torque to the drive shaft.

Based on duty cycles, Golin contends, it makes sense to “go one way or the other”—hydraulic or electric. While he says there’s no overlap or competition between the two offerings, he believes the stop-and-go cycle of a refuse truck doesn’t allow an electric system enough time to recharge. A hydraulic system is at full torque at 0 rpm with five seconds to recharge, limited only by the capacity of the accumulators.

Keeping an eye on the future, McNeilus, which builds bodies, not chassis, develops strategies to dovetail with chassis changes. “We’re in tune with what they’re doing,” Swertfeger says. “Nothing happens in a vacuum.” One thing the builder, with customers ranging from major fleets like Republic and Allied to small mom-and-pop fleets and municipalities, has looked at is hydraulic launch assist. “That’s a technology we’re watching, but we feel there are better solutions, like CNG, that require far less modification to the body and chassis.” He hopes for newer technology that is more efficient and poses fewer challenges for body manufacturers.

Golin, on the other hand, says HLA provides better acceleration, is quieter, saves brakes, produces fewer emissions (nitrogen oxides, carbon dioxide, or particulates) and improves productivity, allowing operators to make more stops in the same amount of time. “Refuse is a great market for HLA because they stop up to three times per minute.”

HLA, a parallel hybrid hydraulic regenerative braking system that supplements the engine, recovers the majority of the energy normally wasted as heat during braking and uses it to supplement the engine’s power during acceleration. In contrast, a series hydraulic system replaces the transmission and provides engine management. At peak efficiency, an engine generates 33%–34% of the energy it takes in. With the series system, Golin explains, the way to do engine management is to always run the engine at optimum speed and let the hydraulic system manage the torque.

HLA provides more torque for quicker acceleration and shorter cycle times and still provides a 20%–25% savings in fuel consumption during refuse collection while reducing emissions of nitrogen oxides, particulates, and carbon dioxide. Conversely, the series hybrid provides higher savings.

Proving that the current financial crunch isn’t new, Golin reveals that Eaton, with an annual revenue of $12 billion to $13 billion and five divisions, has spent 15 years developing the HLA technology. “The driving force is efficiency: Less energy to power equals fewer operating costs.”

Eaton plans to release the HLA system for use in Peterbilt 320 refuse chassis in the second half of 2008. It could be retrofitted to other models, Golin speculates, but requires a lot of integration work. The series system is even more integrated as it replaces the transmission. “Delivery trucks are a good target for Series. These trucks last 20 years, so the installed fleet is huge in comparison to new truck purchases each year.” Peterbilt and other original equipment manufacturers that install HLA require a payback of about three years. “A truck costs $150,000–200,000. Our product is $40–$45. The life of a heavy-duty/severe duty garbage truck is seven to 12 years. It’s used hard.”

Putting It out There: Emissions
Refuse truck brakes are also used hard. Vatter says the number-one expense in the refuse industry is fuel, followed by brakes. Their life is usually one month, but he insists that Autocar’s hydraulic hybrid can extend their life twofold to threefold. “The maintenance schedule goes from one to three months.”

Autocar focuses on details like brakes because, as Vatter states, “We know trucks, manufacturing, and the needs of this market. Others trying to develop technology aren’t in the truck industry.” They know the market—and that there were performance deficits in the ’80s —but Vatter says those have been overcome. “The Cummins has 320 horsepower and 1,000-foot-pounds of torque. The proof is there now.”

They also know private companies are watching their carbon footprint and want to go green—and that many municipalities are insisting they do just that. “There will be more restrictions on emissions in the future. California offers state grants for hybrid technology to make adoption quicker,” Vatter says. “There are incentives to help clean air. Toronto is going green with its non-idle decree.”

That suits Heil’s Operate-at-Idle system, standard on all automated side loaders and optional on most rear-loaders, front-loaders and side-loaders. It saves fuel and increases productivity by enabling the vehicle to perform all of its normal functions to load and/or compact refuse at standard operating speeds while the vehicle engine is at idle.

“With 2010 looming, reduced emissions is obviously a focus,” Swertfeger confirms. “Diesel fuel costs continue to rise and relief seems to be somewhere in the distance. The thought of alternative fuel is becoming much more attractive. It’s the wave of the future. A lot of attention is focused on this.”

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Charest verifies that the industry is “working hard to meet emissions regulations: 2010 is the next challenge. After that, it will be tough to get cleaner. There will be no visible smoke [and] nitrogen oxide will be down to such a low level, it will be tough to measure.” That, he says will make improving fuel economy very difficult. “You’re talking a few percentages.”

With a hybrid, higher percentages can be achieved. Mack is looking at that and other technical issues, with some financial assistance from the US Air Force to use four trucks with similar weight rating to dump trucks. “It helps define where we’re going.” Swertfeger speaks for many manufacturers in the industry when he says McNeilus will be ready to move whichever way the industry goes. Nycx adds, “We’ve evaluated 2010 solutions and are focused on the right technology for the market and various geographical regions.”

Author's Bio: Lori Lovely is a writer based in Indianapolis.

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