Grading and Excavation Contractor | New Trucks Offer Improvements

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A look at several manufacturers' new construction trucks.

By Daniel C. Brown

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Automatics Score With Construction Truckers

The construction truck industry is buzzing with news these days. Mack has a new construction truck and a new engine. Peterbilt has an all-new lineup, including two new construction trucks that replace the venerable Model 357. And International has announced improvements.

Meanwhile, truck and engine manufacturers have figured out how to meet 2007 exhaust emission regulations. The changes are not very drastic, but dealing with the exhaust heat is a challenge. How that will be resolved remains to be seen.

At a sales conference held last October, Mack announced new Granite and Granite Axle Back models, which both feature a 116-inch bumper-to-back-of-cab (BBC) dimension. Both the new Granite and the new Pinnacle on-highway tractor have been designed around the new MackPower (MP) engine.

Mack’s new MP7 engine is an 11-liter power plant available in the company’s three engine families—the Econodyne, the Maxidyne, and the Maxi-Cruise. Each of those names denotes a torque curve, says Steve Ginter, vocational product manager. A Maxidyne engine has a 60% torque rise—very rapid for high startup power. A Maxi-Cruise engine has slightly less torque rise, about 50%, and it fetches somewhat better fuel economy than the Maxidyne; both of those engines are used in vocational applications. The Econodyne is a conventional torque rise engine, 32% to 33%, and is used for line-haul tractor-trailer rigs.

The MP7 will be available in six horsepower ratings ranging from 325 to 405 horsepower, with torque ranging from 1,260 to 1,560 foot-pounds. The MP7’s base architecture is the heart of Mack’s solution to 2007 EPA emission regulations. Key components of the MP7 include:

High-performance (cooled) exhaust gas recirculation. With this technology, exhaust gas is removed from the exhaust stream, cooled, and placed back into the intake side of the engine. As that gas mixes with the air and fuel, it inhibits combustion somewhat, and the result is a lower flame temperature and lower NOx levels.
Variable-geometry turbocharger with sliding nozzle ring. The sliding ring adjusts boost pressure to drive the exhaust gas and charge air into the engine, Ginter explains.
Electronically controlled unit fuel injectors
Single overhead cam with four valves per cylinder
Wet sleeve cylinders with single-piece steel pistons
Rear gear train offers a rear-engine power-take-off option

“Construction customers in particular will appreciate the new engine’s tremendous low-end torque response,” says a Mack statement. And the MP7 offers an improvement in fuel economy compared to current engines, the company says. Oil drain intervals are pegged at 300 hours, or 15,000 miles for construction users.

“For this year we have available a limited quantity of Granites with an MP7 engine, but without the systems needed to meet ’07 emission requirements,” says Ginter. “At the end of 2006 we will add the aftertreatment systems needed to meet the ’07 standard.” That largely means a diesel engine particulate filter. “The impact of the filter on fuel efficiency is still being determined,” says Ginter.

Previously, to meet emissions rules on vocational trucks, Mack used what it calls internal exhaust gas recirculation. The engine used a consistent, predictable amount of exhaust gas on every engine revolution. Not so with the new external, cooled EGR in the MP7 engine. To meet the emission standard and performance requirements, the MP7 will use a variable amount of exhaust gas mixed with charge air. “It raises the sophistication of the engine to a new level,” Ginter says.

Photo: Peterbilt

One vehicle in Peterbilt’s all-new truck range

New From Peterbilt
At a trade show in March, Peterbilt introduced an all-new truck range, including the Models 365 and 367 to replace the Model 357, which had been improved over the course of some 20 years. Both new models will be available with set-back and set-forward front axles, says Al Zwicky, senior applications engineer at Peterbilt. The BBC dimension is the primary difference between the two: The 367 is 8 inches longer than its brother and will accommodate a larger engine.

Peterbilt also introduced a 367 Heavy Haul tractor, which has a slightly different hood design to provide for a larger cooling package. That’s an issue with the new EGR systems.

On the Model 365 Peterbilt moved the axle back somewhat, compared to the 357, to provide more front-end weight distribution. Steering geometry was changed to provide better maneuverability. Headlamps were improved for better forward lighting and visibility over the hood.

And three new cab interiors are available on the Models 365 and 367, says Ken Marko, manager of market planning and research. The high-end interior is called the Platinum, the Prestige is the mid-level interior, and the Pro-Built is optimized for rugged durability, says Marko. All three interiors feature a new dash, more grab handles for entry, and an improved fit and finish. “It’s almost like a Lexus quality,” says Marko.

Peterbilt’s 2007 version of trucks will have diagnostic text messaging available on the dash to provide news of what’s wrong with your truck. “You won’t need a cross reference to tell what’s wrong,” says Marko.

Axle weight ratings were not changed from the 357. And while horsepower ratings had not been released at press time for the 365 and 367, Peterbilt says they will compare favorably to offerings on the 357. It would fit anything up to a 625-horsepower Caterpillar engine or the big-bore Cummins ISX.
Allison automatic transmissions will be available on both the 365 and the 367, Marko says. Allison’s 4000 series transmissions come with speeds ranging up to seven on the 4700.

We asked Peterbilt about new stopping distance rules being proposed by the National Highway Traffic Safety Administration (NHTSA). “We anticipate changes,” says Zwicky. “We are developing air disc brakes; this year we will offer air disc brakes as an option for front axles on all Peterbilt models, and next year we’ll offer them on drive axles.”

Photo: Kenworth

Kenworth’s extended cab/Splendor interior

Photo: International

International's new 7000 series trucks include a raised and widened hood.

International’s Changes
To accommodate a larger radiator and meet 2007 emission rules, International has raised and widened the hood slightly on its 7000 series trucks. By keeping the radiator above the frame rails, International can still offer a front power-take-off (PTO) under the radiator. “With the high demands of construction, municipal, and waste industries, maintaining the front PTO option is an important feature to our customers,” says Bill Sixsmith, International’s director of severe service marketing.
In addition to the new hood design, the new look of the International 7000 will include dual air intakes, rounded headlights, a hood hatch for snowplow applications, front fender extensions, a larger chrome grille, and a new interior.

Moreover, Sixsmith says International will offer the Cummins ISL engine, which can range up to 350 horsepower, in the 5500 and 5600 Series trucks. “That can save you 500 or 600 pounds over a big-bore engine,” says Sixsmith. “This will be good for mixer or dump truck applications. For shorter-distance hauling the ISL is fine, but it won’t handle the constant pounding of long-haul trucking that a bigger-bore engine can take on.”

Sterling’s L-line
Sterling Truck Corp., which evolved from the old Ford heavy-duty lineup, offers its L-line of construction trucks in four BBC dimensions: 101 and 111 inches in set-forward axles, and 113 and 122 inches in set-back axles. Horsepower ratings run from 250 to 475 in Caterpillar, Cummins, Mercedes Benz, or Detroit Diesel engines, says Shawn Waterman, Sterling’s marketing segment manager.

To allow space for the new 2007 exhaust system on the right-hand side under the cab, Sterling has eliminated the fuel tank that normally fits in that location. Typically that reduces fuel capacity by 55 to 70 gallons, Waterman says. “The best you can do about it is to make the left-hand tank bigger,” he says.

Because of this aftertreatment exhaust device there is no more room on a construction truck for the right-hand fuel tank. You can probably put a 120-gallon tank on the left-hand side.”

Waterman says Sterling sells more Eaton-Fuller transmissions than any other type, and they range from a 7- to an 18-speed gearbox. “We sell more and more automatics every year; they probably run on 8% of construction trucks,” says Waterman (see sidebar). “They’re becoming much more popular on mixer trucks.”

Freightliner’s Business Class
“The Business Class M2 is Freightliner’s most popular construction dump truck,” says Jonathan Randall, director of marketing with Freightliner trucks. The company offers the Business Class M2 in two 106 BBC set-back axle versions; one is aimed at general On and On/Off highway markets and the second is the M2 106V for more specialized vocational use. The 106V adds certain options such as a front-engine PTO, front frame extensions integral with the main frame rail, hood hatches, and engine air intake systems that include under-hood blend air and/or a passive air precleaner. The 106V is available with a front gross axle weight rating of 20,000 pounds for vocational use. Engines available on the M2 106 range up to 400 horsepower.

Photo: Volvo

Volvo's VHD truck, available in axle-back and axle-forward configurations

Photo: Mack

Granite Axle Forward Dump from Mack

Freightliner also offers the longer Business Class M2 112 in two versions, and the vocational model has the same options as the 106V. Either the conventional M2 112 or the 112V can have a 20,000-pound front axle. The M2 112 can handle large bore engines up to 450 horsepower, including the Mercedes Benz 4000 Series.

For really serious construction use, Freightliner builds the FLD 120 SD, which can be configured as a tractor or a straight truck, as can all of the company’s Class 8 trucks. This truck can take on up to 86,000 GVWR with a single pusher axle. The FLD 120 SD is available with either a set-back or a set-forward front axle. Available engines include the Mercedes Benz 4000 series up to 450 horsepower, Detroit Diesel’s Series 60 up to 515 horsepower, and Caterpillar’s C15 model.

“The most significant issue about 2007 emissions regulations is the heat of the exhaust system,” says Ivan Neblett, vocational product manager. To reduce particulate emissions, an aftertreatment device will replace the muffler on the right-hand side—either under the cab or behind it. The aftertreatment device will contain a diesel particulate filter to capture the soot and ash in the exhaust. With passive regeneration the normal exhaust gas temperatures of the engine will burn and reduce the particulate matter.

“But over time, higher temperatures of an active regeneration event within the aftertreatment device may be required to burn off the soot,” says Neblett. “Some body manufacturers have said all that heat generated by the exhaust could be an issue with their installations They’re looking at things such as synthetic bed liners instead on heated dump bodies. Solutions are still in process.”

Randall says Freightliner supports NHTSA’s efforts for safety through reducing track tractor stopping distance. “Freightliner supports a way to reduce stopping distances by 25% on 6 X 4 tractors,” says Randall. “There is still some work to be done for other configurations such as 4 X 2 and severe-service tractors.”

Volvo’s VHD truck
For construction, Volvo offers its VHD vocational line in axle-back and axle-forward configurations at 113-inch BBC. The VHD can be ordered with up to six axles, and even comes with three driving axles in an 8 X 6 configuration. Volvo offers its own proprietary front axles rated up to 22,000 pounds and Arvin Meritor front axles rated up to 20,000 pounds. Volvo rear axles are rated at 58,000 pounds and 65,000 pounds, and rear Arvin Meritor axles range up to 58,000 pounds.

“In 2007 models we use our new engine, the Volvo D13, a 13-liter engine rated at 335 to 485 horsepower,” says Frank Bio, product manager with Volvo Trucks North America.

Volvo offers Eaton-Fuller transmissions ranging up to 18 speeds and Allison automatics in four-, five-, and six-speed versions.

Regarding the new stopping distance rules, Bio says, “We feel comfortable that we will be able to meet the rules with cam brakes and disc brakes. The government has collected its comments on the proposed rule and they expect to issue a ruling this year.”

Daniel C. Brown is the owner of TechniComm, a communications business based in Des Plaines, IL.

GEC - July/August 2006