Testing selective catalytic reduction (SCR)

Improved fuel economy. More power. Less active regeneration. And above all, miniscule amounts of pollutants from the tailpipe. These are but some of the metrics Mack Trucks is establishing through an 18-month field test of a 2010-model Granite four-axle end dump truck equipped with a selective catalytic reduction [SCR] system, on loan to construction firm Haines & Kibblehouse, Inc. – a subsidiary of the HK Group – based in Skippack, PA.

“Everything we said we could do with this emission-reduction technology we are doing – and we’re exceeding our goals in some areas,” David McKenna, powertrain sales and marketing manager for Mack Trucks, told FleetOwner. “We’re using less DEF [diesel exhaust fluid] than we thought; we’ve reduced demand for active regeneration by 80% to 100% in some cases; and we’re seeing up to an 18% improvement in fuel economy over pre-2007 engines and up to a 5% fuel economy improvement over our '07 package, depending on the duty cycle."

Based on the results they’ve gained so far from the test trucks with Haines & Kibblehouse – which have only been with the company for five months, logging some 50,000 mi. of operation – McKenna said Mack will be able to increase engine power ratings in this vocational segment without sacrificing fuel economy.

“Right now, we’re testing an SCR-equipped Mack MP8 in this truck – a 13-liter engine producing 485 hp,” he said. “In 2010, we’ll be able to increase that to 505 hp yet get better fuel economy when compared to the 485 hp rating. That’s going to give fleets in this segment a lot more torque and power for accelerating on highway ramps under load.”

Jimmie Kissling, one of the Haines & Kibblehouse drivers issued a 2010 test truck, told FleetOwner the vehicle gets on average 5.4 mi. per gal. across its daily duty cycle – loaded and unloaded, at highway speed and in stop-and-go traffic – yet offers plenty of power to get the job done. “It pulls real good under load on hills and on highway ramps,” he said, “I also don’t have to stop and go to active generation at all anymore.”

The 2010 Granite test dump truck has also proved maintenance free, with little difference from the current models Haines & Kibblehouse works on every day.

“We haven’t had any maintenance issues with this truck at all,” Dan Alderfer, fleet superintendent for Haines & Kibblehouse, told FleetOwner. “We do all the general preventive maintenance here and there’s just not much different on this truck we need to worry about relative to our daily maintenance practices. Of course, higher cost for the vehicle is a given – that’s not a question we ask. But everything else is better than our current trucks, especially fuel economy.”

Alderfer noted that while the 17-gal. DEF tank is topped off every day for testing purposes, a full DEF tankload could last two weeks based on the data they are seeing. More importantly, there’s no diesel smell or black soot anymore from the tailpipe.

“You know, three years ago if you told me the exhaust on one of our trucks would be cleaner than the air we breathe, I’d think you’d be joking,” he said. “But it’s not a joke – it’s reality. And it can help us, too. We work plenty of jobs in parking garages, for example, which require us to use air scrubbers due to the exhaust from our diesel trucks. We may not need to do that anymore.”

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