Trucks
New Engines: Time to Clear the Air
Full-service leasing offers answers to fleets facing two engine emission control choices.
Olen Hunter
In response to new federal emission standards that went into effect Jan. 1, 2010, in the U.S. and Canada, engine manufacturers selected one of two choices to achieve a reduction in emissions of oxides of nitrogen (NOx). They either provide an in-cylinder approach through increased exhaust gas recirculation (EGR) only, or an engine aftertreatment approach using selective catalytic reduction (SCR) technology, in combination with exhaust gas recirculation.
The choices in engine technology available to truck and private fleet operators have never been so different and making the right choice has never been so important for companies to control their fleet operating costs, get more mileage out of the engines and gain a competitive edge.
Full-Service Leasing Makes Choice Easier
New engine emission control standards offer one reason why companies should consider full-service leasing from a company that understands the 2010 U.S. Environmental Protection Agency-compliant engines. One that has a strong relationship with engine manufacturers and close ties to truck manufacturers can help companies make informed choices about trucks with 2010 engines.
Leasing can help take the guesswork out of specifying and servicing 2010 engines. Plus, the leasing company can handle any warranty issues and take over any risk associated with truck resale values.
Either Way, Expect a Price Increase
Regardless of which engine operators choose, they will see a price increase in the engine. By leasing their trucks, companies can spread that cost over time. Over a typical six and a half year lease term, a $9,000 price increase for the engine will increase the monthly lease payment by about $120.
By choosing the right 2010 engine emissions reduction technology, companies can realize some reductions in operating expenses over the life of the truck. Namely, the 2010 engine in a Class 8 truck using SCR technology can offer a net 3 to 5 percent improvement in fuel economy when compared to 2007 engines.
Fuel Economy Improvement Can Offset Costs
Consider a fleet running a Class 8 truck with a 2010 SCR engine 125,000 miles per year and getting 6.5 mph fuel economy. With diesel at $3.25 per gallon, when you factor in the 3 percent net fuel economy savings over a typical six and a half year lease term, the company can expect to save $11,830, or $151 per month. This more than offsets the increased cost of the SCR technology. Plus, full-service leasing can make it easier to acquire the new engine technology. You do not have to deal with a large upfront cost or maintenance of the truck.
But how does SCR technology deliver this net 3 percent improvement in fuel economy?
To fully understand, truck operators should become more familiar with SCR technology and the increased EGR approaches to emission reduction.
SCR versus EGR
Both the SCR technology and the increased EGR approaches use EGR to circulate a portion of an engine’s exhaust gas back to the engine cylinders to achieve a reduction in emissions. Also, both methods use a diesel particulate filter to remove particulate matter from the engine exhaust.
The SCR technology approach uses a reductant and a catalytic converter to achieve the NOx emission reduction now required by the U.S. EPA and Environment Canada. The increased EGR approach recirculates a significantly larger portion of the engine’s exhaust gas back to the engine, where the NOx emission reduction occurs. The increased EGR approach is often referred to as an “in-cylinder” approach.
SCR accomplishes NOx reduction by mixing the oxides of nitrogen in the exhaust gases with a reductant, most commonly a solution of urea and de-ionized water also known as diesel exhaust fluid (DEF). The exhaust passes through a decomposition tube, where the DEF is introduced through a dosing valve. The exhaust then passes through a cylindrical chamber, also known as the SCR catalyst. Here the DEF reacts with the NOx, breaks it down, producing oxidizing ammonia. The oxidizing ammonia chemically reacts with the NOx, converting the pollutants into nitrogen, water and tiny amounts of carbon dioxide. The SCR catalyst contains a honeycomb-like substrate, which also reacts with the pollutant, converting it into nitrogen and water.
Increased EGR accomplishes NOx emission reduction by increasing the amount of engine exhaust gases into the engine cylinder, slowing and cooling the combustion process. Increased EGR doesn’t require introducing DEF into the exhaust stream to reduce NOx, but it does require more fuel to be injected into the diesel particulate filter for active regenerations. The increased heat created with the enhanced EGR approach also requires greater cooling capacity for the engine.
SCR Allows Manufacturers to Build Better Performing Engines
Although it’s new to North America, SCR technology is currently used in more than 600,000 trucks around the world. SCR has proven its ability to meet European Union emission reduction requirement for many years (see Cummins Experience with SCR Technology sidebar).
From an engine performance standpoint, because the SCR after-treatment system handles the NOx reduction downstream from the engine, SCR allows manufacturers to develop engines that last longer and work more efficiently.
Not all SCRs Built the Same
Operators looking at different SCR engine choices should also consider that even among the different SCR engines, two major choices have emerged. One common SCR engine platform uses iron zeolite in the aftertreatment system catalyst while the other uses copper zeolite.
Copper zeolite is more efficient at reducing oxides of nitrogen at normal engine operating temperatures than iron zeolite. This means that engines using copper zeolite as the aftertreatment catalyst are expected to enjoy a fuel economy improvement. That’s because the SCR catalyst is doing the work and not the engine to get the levels of oxides of nitrogen down below the EPA threshold. Trucks with engines that are less complex and offer longer life, better fuel economy, greater reliability, improved driveablity, and higher power density for better throttle performance, will retain higher resale values.1
Considering Full-Service Leasing
While full-service leasing offers benefits, including the ability to preserve lines of credit for core business projects or other revenue-generating endeavors, it can also help make choosing a truck with 2010 engine technology easier and more affordable. If you’re considering acquiring trucks with 2010 engines for your fleet operation, consider your two choices in emission control, and know full-service leasing may offer the best way to go about it.
Olen Hunter is director of sales for Bellevue, WA.-based PACCAR Leasing Company (PacLease). He has 18 years of full service leasing experience. PacLease is one of the fastest-growing commercial truck leasing companies in the transportation industry. PacLease has independent and company-owned full-service leasing locations throughout the United States, Canada, Mexico, and Germany. PacLease provides customized full-service lease, rental and contract maintenance programs designed to meet the specific needs of customers. With its close association with truck manufacturers Kenworth and Peterbilt, PacLease understands the spec’ing requirements associated with 2010 engines and how they can affect the performance of the truck for a waste hauling application.
A combination of reliable, custom-built trucks and complete service offerings allows customers to maximize the value of their transportation resources. Olen can be reached at [email protected].
Note
Lou Wenzler, on-highway communications director for Cummins
Sidebar
Over 50 Million Miles of Real World Testing Proves SCR
PACCAR conducted more than 50 million miles of testing using customers in real world applications across North America when it developed its PACCAR MX engine. The tests compared, among other things, the fuel economy of trucks equipped with PACCAR MX engines against the fuel economy of trucks equipped with 2007 EPA-compliant engines. PACCAR also conducted an additional 300,000 hours of lab and track testing.
Test results, coupled with the experiences of operators elsewhere around the world, consistently demonstrated a net 3 to 5 percent improvement, minus the cost of diesel emission fluid. Even extrapolating a conservative estimate of a 3 percent net improvement, a fleet can expect big savings over time. In reality, the fuel economy improvement could pay a fleet’s additional cost to lease the new engine technology.
Sidebar
SCR Allows Manufacturers to Build Better Performing Engines
Lou Wenzler, on-highway communications director for Cummins, said Cummins has longstanding experience with SCR technology. Cummins has built and shipped more than 74,000 engines with SCR aftertreatment systems. Cummins Emission Solutions, a division of Cummins components business, has built and shipped more than 300,000 SCR aftertreatment systems.
EGR: The Road Not Taken
Cummins initially developed an EGR-only approach to attain emission reductions for on-highway, heavy-duty engines. Its engineers accomplished the reduction, but at a significant cost to the engine’s performance. The reductions in emissions narrowed the engine’s maximum speed range for optimum efficiency, or its “sweet spot,” he added.
A truck with an engine that has a narrower sweet spot can be more challenging for inexperienced drivers to operate while still maintaining optimum fuel efficiency, Wenzler said. That can result in widely varying fuel economy results across a company’s fleet.
SCR: Better Results
Wenzler said Cummins decided in August of 2008 to abandon plans to use the EGR-only approach in heavy-duty engines in favor of SCR aftertreatment technology. Cummins 2010 ISX 15 and ISX 11.9 heavy-duty engines incorporate SCR technology into the Cummins Aftertreatment System. This technology choice, coupled with the new XPI fuel system and VGT Turbocharger, will provide customers up to 5 percent improved fuel economy over the 2007 ISX, he added.
SCR engine manufacturers don’t have to install larger radiators and two turbochargers to get additional airflow to cool the engine, he added. Nor do they have to equip the engine with a large intercooling chamber, which adds additional hardware, making it more difficult to service. This all leads to greater reliability.
“There’s no diminished life-to-overhaul,” Wenzler said. “Service intervals remain the same on 2010 engines as they were before the new regulation took effect. The only change is the addition of new, but simple DEF filter service intervals, usually about 200,000 miles depending on the engine manufacturer’s recommendations.”
Sidebar
Diesel Exhaust Fluid is Safe and Widely Available
Diesel exhaust fluid is a non-toxic, non-hazardous and non-flammable solution made with urea and de-ionized water. Since it has a pH level of 9, which is equivalent to baking soda, it’s safe to handle and store. If kept at a constant temperature around 68 degrees, it has a shelf life of more than 59 months. Even if the ambient temperature reaches 104 degrees, its quality will still remain within specification for two months.
At a dose rate of about 2 to 3 percent of diesel fuel burned, a company with an over-the-road truck averaging 120,000 miles annually and 6 mpg fuel economy, for example, can expect to fill up the DEF tank 20 times and go through about 400 gallons. DEF (spell out) has become widely available at dealerships, fuel stations, and truck stops across North America. While DEF’s retail cost can vary, it’s generally equivalent to the cost of diesel fuel.
Vehicles equipped with SCR systems have a gauge on the dashboard that informs drivers of fluid levels in the DEF tank and a warning system that offers them graduated alerts as the tank reaches certain levels. If the tank runs out of DEF or if the DEF becomes contaminated, the truck’s engine will derate, but still run at reduced speeds.
The SCR systems also employ a heating system in the DEF reservoir and lines to keep the fluid from freezing. They’re also designed to automatically purge the lines before the engine shuts down. Still, should it freeze in extreme cold conditions, quality DEF is specifically formulated not to become diluted with water or concentrated with urea as it thaws.