Contract sweepers have likely heard about the Environmental Protection Agency's (EPA) emission regulations, but regulations taking effect in 2010 will have an impact on the trucks you buy and, at least in California, on the trucks you already own.
Finalized in 2001, the EPA's Highway Diesel Rule required that harmful pollutions from engines be reduced by more than 90% beginning with 2007 model year engines. For 2010, the EPA will tighten the emissions standard by requiring new diesel engines to emit no more than 0.2 grams of nitrogen oxides per horsepower-hour.
In order to comply with EPA regulations, engine manufacturers are incorporating one of two technologies in their new engines: Selective Catalytic Reduction or Exhaust Gas Recirculation. Most engine manufacturers are using Selective Catalytic Reduction technology in their engines, says Brian Giles of Elgin Sweeper.
Selective Catalytic Reduction
Selective Catalytic Reduction (SCR) is a technique for reducing nitrogen oxides (NOx) by injecting a fine mist of urea plus water through a catalyst into the engine's exhaust stream. This creates a chemical reaction turning the nitrogen oxides into nitrogen and water vapor. When heated during the SCR process the urea mix, also called diesel emission fluid or diesel exhaust fluid (DEF), turns into ammonia and carbon dioxide. These by-products, natural elements of the air we breathe, are then discharged through the tailpipe.
With SCR the nitrogen oxides reduction process takes place after combustion. Some of the benefits SCR is said to have include: enhanced thermal efficiency and fuel economy, reduction of heat rejection and cooling system stresses, and possible emissions reduction up to 90%.
Because SCR requires the use of urea, trucks with this technology will require an onboard tank to hold the urea. Failure to maintain this tank and urea levels might result in a reduction in torque output for the sweeper.
EPA mandates that engine manufacturers limit the vehicle speed to 5 mph if the system detects any attempt to tamper with or defeat the system, says Charlie Cox, an emissions technology consultant with Ironman and a speaker on this topic at the upcoming National Pavement Expo West, Dec. 3-5 in Las Vegas.
A nitrogen oxides sensor will also be needed to ensure the urea level is not neglected. The engine's computer management system will be able to detect "fake" diesel emission fluid, warn the driver when the diesel emission fluid level is low, and will disable the engine if it detects any attempt to tamper with or defeat the SCR system, Cox says. Urea freezes at 12°F, so trucks that operate in colder environments may also need heated storage for the urea tank.
Exhaust Gas Recirculation
Exhaust Gas Recirculation (EGR) technology recirculates exhaust gases back into the engine air intake cylinder and burns them again. EGR takes some of the exhaust gas from the diesel engine, cools it and blends it with fresh air, then recycles it back through the engine to dilute the amount of oxygen in the intake charge. This process reduces the temperature of combustion and lowers the formation of nitrogen oxides. The reduction in oxygen mixed with the use of cooled EGR can reduce emissions up to 90%.
EGR technology does not require any tanks to be added to a vehicle, but the addition of EGR coolers increases the overall engine size, and additional heat loads from the recycling and reburning of exhaust could increase the amount of cooling capacity required.
Effects on sweeping
So how do these new engine technologies affect contract sweepers? It depends on what type of truck you are running and whether or not you work in California. Twin-engine sweepers feature an on-highway engine in the front and an off-highway engine in the back. Since the front engine is an on-highway engine, it will need either SCR or EGR to comply with the 2010 regulations. However, the back, off-highway engine is less critical to the contractor at this point and will probably not need SCR or EGR technology until Tier 4 requirements in 2012, Giles says.
A single-engine sweeper is an on-highway vehicle and subject to the 2010 regulations. Although Giles points out that the buyer (contractor or public agency) has no control over which technology an engine manufacturer uses, the buyer might be able to choose what manufacturer's engine he wants in his sweeper. Or the contractor can at least visit with his truck manufacturer to see what engine manufacturers are used or which truck manufacturers will build sweepers on their trucks.
"Privately-owned sweepers, whether they employ two engines or a PTO (power take-off), are part of California's Truck & Bus Regulation," Cox says. And the California Air Resources Board has recently posted its latest version of its Truck & Bus Regulation. Cox says sweeping contractors working in California should review this text, especially section 2025 (n) "Requirements for Two-Engine Sweepers." Contractors can find this document on the Air Resources Board's website (www.arb.ca.gov/regact/2008/truckbus08/attach1.pdf).
Cox says every truck engine manufacturer except Navistar is incorporating SCR technology to make their 2010 engines compliant. "Navistar has opted to employ what is called 'massive EGR,' which does not meet the EPA 2010 emissions standards but the company will use emissions credits they've accrued to allow them to sell these engines," Cox says.
If the single-engine truck is using SCR, contractors will need to be aware of the added maintenance required with the urea tank. But Giles doesn't see that as a major problem. "Sweeping contractors typically go back to the same garage every night. So all they'll have to do is have that supply of urea at that garage, and other than putting urea in it when you put fuel in it at the same time that's all there is to it," Giles says. "There are some concerns about cleaning and maintenance, but people will learn to deal with that and it will become second nature."
Because these new engines and technologies are not free, there will be an added cost to contractors who are purchasing these engines or purchasing sweeping trucks with these new engine technologies.
Cox estimates that it may add another $6,000 to $10,000 to the cost of new sweeping trucks depending on the technology and engine manufacturer. If the engine employs SCR technology, contractors will also have the added cost of purchasing urea, Cox adds.
What if you weren't planning on purchasing a new truck any time soon? At this point in time, Giles says he doesn't see the 2010 regulations affecting most previously purchased sweeping trucks, except in California. "Right now, California is the only state that says 'Yup, you bought that fairly new, perfectly functioning engine years ago but it's not legal anymore,'" Giles says. "However, I've seen no indication that 'life limits' on engines is going to happen outside of California." But contractors still need to be aware of these engine technologies because most likely they will be in place on any sweeping trucks a contractor purchases in the future.
Get the Latest Emissions Update at National Pavement Expo West 2009
At NPE West, Dec. 3-5 in Las Vegas, Charlie Cox of Ironman will present "Complying with California's New Exhaust and Emissions Regulations" to help further explain and answer questions about the emissions regulation rules and their impact on the sweeping industry. He'll also discuss important definitions all sweeping contractors need to know to understand compliance, and will delve into the technologies that will help bring your sweeper fleet into compliance. For more information or to register visit www.nationalpavementexpo.com and click on NPE West.