Reinventing the engine
Aug 1, 2008 12:00 PM, By Jodie Wehrspann
SCR is widely used in Europe, where motorists pull up to a station to fill up with both diesel and urea. Although the technology is not used in the states yet, some truck manufacturers have announced they will use it to meet EPA's on-highway regulations for 2010, says EMA's Gault.
AGCO is considering using this technology in some of its equipment to reach the Tier 4 interim and final requirements. The company owns Sisu Diesel in Finland, which already builds and markets an engine with SCR technology for use in forestry equipment.
In the end, all manufacturers concede they may need both EGR and SCR to meet the final Tier 4 rules, given the technologies known today.
At what cost?
Both solutions will require added components and new design concepts, which will add to production costs. The EPA estimates that the cost for the advanced emission controls will be 2 to 3% of the total cost of the vehicle. So on a $230,000 vehicle, the new equipment and modifications to handle the larger engine would be about $6,900. However, maintenance costs may be lower due to the use of low-sulfur fuel.
To offset the hefty price tag, manufacturers may offer new equipment features to make the costs more palatable and create an incentive to buy. “[The manufacturers] know what they are up against,” Gault says. “If no one buys the equipment, they won't be in business.
“As far as packaging and equipment configuration, there have been a number of discussions on how all the hardware is going to fit,” Gault adds. He says the added complexity and hardware associated with Tier 4-compliant engines will be a challenge for equipment designers.
Meeting the challenge could lead to drastic design changes. O'Shea says some of the concepts being considered, and not necessarily by AGCO, include a forward-mounted cab that sits over the engine components or an engine placed in the rear, like on a combine.
Fuel economy also may suffer once engines reach the Tier 4 final phase. O'Shea says the technology used to achieve each previous tier typically brought a drop in fuel efficiency. This caused farmers to rush to buy tractors before the next new tier was implemented.
“Tractor engines are going through now what the automotive engines did in the 1970s,” adds Dave Morgan, assistant director, the Nebraska Tractor Test Lab. “Manufacturers are adding technology to the engine to control emissions, and typically that has a negative effect on fuel economy.” However, he says, some companies have bypassed the hit and introduced tractors that maintain, and in some cases increase, fuel efficiency. (Go to http://tractortestlab.unl.edu and click on Test Reports.)








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