No time to do your homework? No worries. We took care of getting tips from the manufacturer for you.

Article and photos courtesy of Kenworth Truck Co.

If you’re in the market for a dump truck, it’s important to do your homework. Unlike some other vocations, dump truck specifications are regionalized. What works in one part of the country doesn’t necessarily work in another.

It’s important to understand how the 2010 federal engine emissions standards may require some changes to be made when spec’ing for new truck purchases compared to your current dump truck spec

That leaves you with a “to do” list. You first piece of homework: Find out what the length and weight regulations are in your state. Try to take maximum advantage of the weight laws to maximize payload. Some states, mostly in the West, require compliance with the Federal Bridge Formula; others don’t. This will have a big influence on how the axles are set up and spaced.

“A Bridge Formula truck will tend to be longer to spread the weight,” says Samantha Parlier, vocational marketing manager for Kenworth Truck Company in Kirkland, Wash. “You may need to have lift axles, but there are different rules on how much load you can add with lift axles. And some states don’t allow lift axles. Your local…dealer will know the rules and regulations.”

In states where you don’t need to comply with the Bridge Formula, you can spec trucks shorter and with higher axle ratings, making them more maneuverable on jobsites.

2010 Engines: SCR OR EGR

It’s also important to understand how the 2010 federal engine emissions standards may require some changes to be made when spec’ing for new truck purchases compared to your current dump truck spec.

“The extent of these changes depends upon each dump truck operator’s choice between two available engine technologies, which may also affect truck performance and operating costs over its lifetime,” Parlier says.

Operators can choose an engine after treatment approach that utilizes selective catalytic reduction (SCR) technology in combination with exhaust gas recirculation (EGR), or an in-cylinder approach through increased EGR.

Both technologies use EGR to circulate a portion of an engine’s exhaust gas back to the engine cylinders and a diesel particulate filter (DPF) to remove particulate matter from the exhaust. A critical difference is the amount of exhaust gas that is recirculated back to the engine; the enhanced EGR approach uses a significantly higher level of recirculated exhaust gases. SCR also mixes a reactant – most commonly a solution of urea and de-ionized water known as diesel exhaust fluid (DEF) – with the nitrogen oxides (NOx) in exhaust gases. The exhaust then passes through a catalyst, where the DEF reacts with the NOx to convert it into nitrogen and water.

Increased EGR reduces NOx by boosting the amount of exhaust gases in the engine cylinder, then slowing and cooling the combustion process and burning off pollutants. The increased heat created with the enhanced EGR approach requires greater engine cooling capacity. Increased EGR also requires more fuel to be injected into the DPF for active regenerations.

“SCR doesn’t rely on engine heat to treat emissions, so SCR-based engines offer the advantage of higher fuel economy,” Parlier says. “Since SCR doesn’t narrow the engine’s maximum speed range for optimum efficiency, or its ‘sweet spot,’ to attain emission reductions, fleets also can still maintain fuel economy at lower or higher engine speeds.”

Not all SCR technology engines are the same, however. “An aftertreatment catalyst using copper zeolite is much more efficient than one with iron zeolite at reducing NOx at normal engine operating temperatures,” Parlier says. “Engines using copper zeolite may enjoy up to an additional 2 percent fuel economy improvement over engines using iron zeolite.” PACCAR engines and Cummins engines both use copper zeolite.

The third choice: Natural gas

For those operators looking for an alternative to a standard diesel engine, natural gas-powered engines for heavy-duty Class 8 trucks can offer a third option. For those operators hauling particularly heavy bulk loads, the Westport GX, based on the Cummins ISX diesel engine, is available in power ratings of 400 to 475 hp and torque ratings of 1,450 to 1,750 pound-foot. Plus, the LNG fuel tanks can be configured to suit the operators’ range requirements.