Painless Pilot

To put it bluntly, John Winter didn't expect much from the 2010 emission control technology his company signed on to pilot test. In fact, Winter, fleet director for BFI Canada, a division of Toronto-based waste conglomerate IESI-BFC Ltd., pretty much resigned himself to dealing with any number of issues like the ones that arose the last time emission regulations were strengthened, back in 2007.

But an interesting thing happened — or, more appropriately, didn't happen. During BFI Canada's six-week pilot test with a Mack TerraPro front loader equipped with a selective catalytic reduction (SCR) emission control system, the truck largely functioned like the rest of the vehicles in the fleet and without any hiccups.

This emission issue is critical for both U.S. and Canadian refuse haulers alike because both operate under the same truck emissions standards — standards harmonized between the United States and Canada decades ago.

“Increasingly, the general approach to setting vehicle emissions standards in Canada is to harmonize them with U.S. EPA federal emission standards as much as possible,” noted the 2001 report “Trucks and Air Emissions” issued by the Air Pollution Prevention Directorate within Environment Canada, that country's version of the EPA.

In 1988, Canadian on-road vehicle emission standards were first aligned with the U.S. standards. In February 2001, Canadian measures designed to continue the harmonization of on-road emission standards were implemented, as well as ones that aligned emission requirements for off-road engines and diesel fuels with U.S. EPA standards.

Winter says that when the 2007 emission-compliant models arrived, the diesel particulate filters (DPFs) on those vehicles created an enormous headache, with Mack having to reprogram the software controlling those components three times. This time around, the SCR system and even the DPF worked well, with little interaction needed by drivers.

“I was pretty skeptical when we got this new truck, to tell you the truth,” Winter says. “The DPF system alone gave us a lot of problems back in 2007, and we thought the same situation might occur with the 2010 technology. But it didn't. In fact, it's pretty much a non-event.”

As an added bonus, the test truck showed improved fuel economy when compared to the hauler's other vehicles. BFI Canada is reporting that fuel consumption with the 2010-compliant truck was approximately 2 liters per hour (L/H) less than the average for the rest of the fleet. (Refuse and other low-mileage/high operating hours vocational fleets frequently measure fuel efficiency in consumption per hour.)

For BFI Canada, a 2 L/H savings translates into 18 liters of fuel conserved per day. Converting for U.S. haulers, that's equal to about 4.72 gallons of diesel per day. At $2.80 (U.S.) per gallon, that equals $13.26 U.S. in fuel savings every day. Furthermore, fuel economy typically improves after an engine has been broken in.

However, with SCR, diesel exhaust fluid (DEF), an ammonia-based liquid that is 67.5 percent water, needs to be consumed as well. BFI Canada reported that its test truck consumed about 1.3 gallons of DEF per day. At a cost of $2.75 US per gallon, the truck consumed about $3.58 worth of DEF per day, netting the fleet $9.68 US in savings every day.

"Typically, every year we've gone through an emission change [2002 and 2007], we've ended up with lower fuel economy," Winter says. "Now, we're actually seeing an improvement in fuel economy. This is a pretty good change."

Putting It Together

Perhaps the biggest issue with SCR-equipped trucks is finding a way to fit all the required components onto an already crowded chassis. (This will not be an issue for haulers using Navistar trucks, as the firm is the only OEM forgoing SCR in favor of advanced exhaust gas recirculation (advanced EGR) technology. See “SCR vs. Advanced EGR” on p. 28.)

In BFI Canada's case, the emission components — the DPF and the SCR catalysts — are packaged vertically behind the cab on the chassis, while the DEF tank is placed right next to the diesel fuel tank. Packaging all of the emission components behind the cab proved to be of benefit for the hauler, in more ways than one.

For starters, the location allows more space for the refuse body and related components. According to Winter, the positioning also made sure the components didn't become an obstacle for his technicians to work around while performing routine maintenance, such as changing the oil and checking coolant and other fluid levels.

BFI also wanted to minimize the impact of its 2010 trucks on its drivers' workdays, so that the employees don't need to keep one eye on the job and one on the truck's emission system. “We put our best driver on this [test] truck, one we knew would get a lot of hours on the road with it but who'd tell us if things were troublesome, etc.,” Winter says. “We have a 7-gallon-equivalent DEF tank on this vehicle, so we wanted to see how much time he'd need to keep it full.”

Any impact of the 2010-compliant trucks on drivers is a big concern, because of the large number of trucks in IESI-BFC Ltd.'s fleet. “We've got about 500 to 600 route trucks operating across Canada, from Victoria Island [on the Pacific Ocean] to Montreal [in the eastern province of Quebec],” Winter says. “In the U.S., we operate about another 1,000 trucks, and our numbers are going to double once the acquisition of Waste Services [based in Burlington, Ontario] is finalized.”

After nearly two months of testing, however, little changed in the driver's day, Winter notes. “About every two weeks or so we were refilling the DEF tank so it didn't become a daily nuisance,” he says. “That was a good thing, for sure.”

With the final specs for BFI's 2010-compliant truck models decided upon, the firm expects the trucks to start rolling into its fleet roughly by the end of the first quarter of this year.

The lesson to be learned from the pilot test, Winter concludes, is this: 2010-compliant trucks using SCR won't impact day-to-day refuse fleet operations much at all. And those fleets using 2010 trucks from Navistar, which don't use SCR, should take heart as well, for it seems all the OEMs learned from the hiccups of the 2007 technology introduction and aren't repeating them as the 2010 mandates go into effect.

Sean Kilcarr is the senior editor of Fleet Owner, a sister publication of Waste Age.

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SCR vs. Advanced EGR

Starting in 2010, new heavy-duty trucks can emit no more than 0.2 grams per brake horsepower hour (g/bhp-hr) of nitrogen oxides (NOx). OEMs will use one of two emission control systems to meet these new regulations: selective catalytic reduction (SCR) or advanced exhaust gas recirculation (advanced EGR). Every truck OEM except Navistar is using SCR.

It's important to note that every truck OEM uses exhaust gas recirculation (EGR) technology to reduce the formation of both NOx and particulate matter (PM). It's just that SCR or advanced EGR is needed to meet the new mandates taking effect in the United States and Canada.

EGR is more accurately described as “cooled EGR” since it re-introduces cooled exhaust air from the diesel engine's combustion chamber back into the engine to reduce the formation of NOx and burn off PM. Depending on operating conditions, EGR systems divert anywhere from 5 percent to 30 percent of an engine's exhaust stream through an air-to-water cooler then back into the combustion chamber. All EGR engines use coolant to reduce exhaust temperature from around 1,100 degrees Fahrenheit (F) to 300 F. Cooled exhaust gases are channeled to a mixer, which ensures that intake air and exhaust gases are thoroughly blended before reaching the engine's cylinders.

In the case of SCR, diesel exhaust fluid (DEF) is injected into an engine's hot exhaust stream to reduce NOx down to the 0.2 g/bhp-hr level. DEF is a water-based solution comprised of 32.5 percent urea and 67.5 percent de-ionized water. The fluid, in conjunction with a catalyst, breaks down the NOx into harmless nitrogen and water vapor. Urea itself is an organic nitrogen-containing compound commonly used in agriculture as a fertilizer.

Advanced EGR, on the other hand, reduces NOx and PM by significantly raising fuel injection pressures at low engine speeds, as low as 800 revolutions per minute. Higher injection pressure increases the surface area of the fuel, leading to a more efficient burn that prevents PM from forming. Multiple injection events at those low speeds in conjunction with high pressure rates, as many as five in a single combustion stroke, also create a smoother combustion event that helps further retard NOx generation. Other key elements include modifying turbocharger rates, optimizing combustion with a redesigned piston bowl and careful calibration of electronic engine controls.

It's also important to note that Navistar's advanced EGR system does NOT reduce NOx down to the 0.2 g/bhp-hr standard. Instead, the OEM plans to use credits accumulated during the last decade by building engines that produced emission levels lower than what were required by the 2002 and 2007 standards.