With Advanced EGR buses, the technology used to meet 2010 standards is an evolution of the same technology used by all manufacturers to meet 2007 EPA standards, thereby reducing need to training technicians. (Part 2)
By David Hillman, from Metro Magazine April 2009 Issue
January 1, 2010, the final phase-in of EPA 2007 Heavy Duty Diesel rule will take effect. This rule requires all diesel engines to be at or below .50 grams per brake horsepower-hour (g/bhp-hr) of oxides of nitrogen (NOx). In the first part of this article (found here) I introduced the two different solutions that bus manufacturers will use to make their engines compliant with 2010 requirements, and described how each technology works: MaxxForce Advanced Exhaust Gas Recirculation (EGR), which IC Bus will use to meet 2010, and Selective Catalytic Reduction (SCR), which all other manufacturers will use. In part 2, I’ll further compare these two solutions and how they will impact you and your business.
Before we get started, let’s recall how these technologies differ in reducing emissions. Advanced EGR takes place within the engine and increases the EGR flow rate, cooling in-cylinder temperatures and decreasing NOx. SCR takes place outside the engine, reducing NOx by adding aftertreatment, which uses urea, to the engine’s current EGR system and eliminating NOx downstream in the exhaust process.
Better for my bottom line?
Especially in this economy, bus operators are concerned about every penny that goes out their door. So let’s first examine the cost of 2010 compliance on your operations.
We all know that when something different is added to our operations, it has the potential to affect our bottom line. Something familiar usually has less of an impact, whereas something very different usually means a greater impact. Advanced EGR engines includes updates to components with which bus operators and service technicians are familiar: interstage cooling (some ratings), twin turbos, EGR coolers, water pump, oil filter housing and oil pan (on V-8’s), and a revised cooling package. Your techs are familiar with these as they are simply an evolution of existing components. You do not need to worry about the costs of new training, additional maintenance intervals, storage for aftertreatment hardware or the on-going cost of urea when it comes to Advanced EGR from IC Bus.
Alternatively, SCR adds unfamiliarity. SCR would be a new technology to your staff requiring new training for drivers and service technicians. Also, the cost of storage for the additional hardware and the ongoing cost of handling and purchasing urea impacts your bottom line.
SCR proponents claim that you will save money with improved fuel economy over 2007 engines. But it is misleading to look solely at fuel economy. Since urea gets consumed as you go down the road, like diesel fuel, it needs to be replenished. That costs money. Information available from operators using SCR in Europe indicates two to five gallons of urea will be consumed for every 100 gallons of diesel burned. I have seen vehicle urea cost around $12 per gallon in Europe and as much as $35 per gallon domestically. Industry experts estimate that the cost of urea could come down at some point, but that remains to be seen. The cost per mile for SCR includes the ongoing cost of urea, and you should calculate that impact on your bottom line.
Looking at both options, we can conclude that even if SCR improves fuel economy and if urea costs come down at some point, then the additional costs of training service techs, storing and purchasing replacement parts for the urea system, and adding a urea infrastructure to your business will add unfamiliarity and costs that are not good for your bottom line.
Which is less of a hassle?
Aside from the costs to your bottom line, let’s weigh the options in terms of hassle for you, your technicians and drivers.
With Advanced EGR buses, the technology used to meet 2010 standards is an evolution of the same technology used by all manufacturers to meet 2007 EPA standards. 2010 emissions are met with advanced fuel injection technology, proprietary combustion bowl design on the pistons, advanced air management, and electronic calibration strategies. It is the next step in the technology path, so service technicians are already well-versed on these engines. Also, the EGR diagnostic requirements and service intervals are unchanged from today’s engines. For drivers, the same driver display on the buses today will be used. In other words, the familiarity of Advanced EGR engines means less hassle for you.
As for SCR, drivers and technicians will need training on the SCR system. For example, because diesel engines with SCR could run with empty urea tanks but would not meet 2010 requirements, EPA rules call for vehicles to be equipped with sophisticated sensors to detect NOx in exhaust. If the sensors detect bad or no urea solution, there will be progressive stages of warning and vehicle response, beginning with warning lights and, a few stages later, ending with vehicle shutdown. Can you afford to have your buses shut down? Operators, drivers and technicians for buses with SCR need to be prepared to be part of the EPA compliance equation, because without urea the vehicle cannot run legally and will eventually lose power if the fluid is unavailable.
Many operators I speak with want to keep driver distractions minimized. A blinking light on the dash can be cause for alarm and an unwanted distraction. Did you know that SCR systems require EPA mandated warning lights, all of which will be new to your drivers and service technicians?
As mentioned earlier, SCR requires additional hardware, including: urea storage tanks, tank heaters and connections, tank level sensors and sensor cables, electric cables, heated lines, urea filter, stainless steel line connectors, inline filters, stop flow valves, screw fittings and electrical connectors, all of which are new to your bus. The additional hardware takes up space. Think about your buses with luggage boxes, wheelchair lifts, air conditioning systems and rear engine configurations where space is at a premium. Where will you put that SCR equipment? As for Advanced EGR, because 2010 adjustments happen in cylinder, these engines take up no added space on your buses.
Do both require Urea?
No, only SCR systems require urea. The addition of this fluid, which currently has limited U.S. availability, is the critical component to making SCR buses 2010 compliant and also a major reason IC Bus chose not to follow the SCR plan. “We wanted our engines to meet 2010 compliance without urea. Urea is too big of a burden to put on our customers,” said John McKinney, president, Global Bus Operations, at IC Bus.
Have you thought about how you would handle and store urea? Urea is not as tame as, say, windshield washer fluid. In fact, the International Organization for Standardization created a nine-page document (ISO 22241-3) prescribing the correct handling and storage procedures and a 43-page document (ISO 22241-2) detailing testing required to confirm quality levels needed for vehicle-grade urea. These documents bring up important guidelines about urea, including:
* Urea freezes at 12 degrees Fahrenheit. SCR-equipped vehicles will require a tank heater and heated lines to prevent the urea from freezing.
* Urea begins to break down at 85 degrees Fahrenheit, decomposes into an ammonia gas beginning at 122 degrees Fahrenheit and should not be stored for prolonged periods above 80 degrees Fahrenheit.
* Urea storage tanks must be insulated and shielded from direct sunlight to avoid algae growth.
So there are clear differences in SCR and MaxxForce Advanced EGR. Only one solution has less financial impact on you, is virtually hassle-free and doesn’t require you to add urea to be compliant. “We believe Advanced EGR is the more customer-friendly solution. It’s better for the bottom line and it’s less hassle,” added McKinney. McKinney advises that you ask your bus dealer the questions on your mind when it comes to this decision and your next bus purchase, such as:
* How will my buses be different in 2010?
* Will there be added space required to fit your system that will impact my bus?
* What additional training and maintenance will be needed with your system?
* What are some leading European bus manufacturers now preferring Advanced EGR to SCR?
* What does your 2010 solution mean for resale value?
When you weigh both options for meeting 2010 standards, it seems that the choice is clear.
For 2010, North America bus customers will have two choices to be compliant: they can either buy an all-new, add-on after-treatment system using SCR in addition to EGR, which will be offereed by most bus manufacturers. Or, they can continue to use an in-cylinder solution with advanced EGR, offered by Navistar in its IC Bus brand school and commercial buses.
By David Hillman, From Metro Magazine, February/March 2009
On January 1, 2010, the U.S. Environmental Protection Agency (EPA) will fully implement the 2007 Heavy Duty Diesel rule, which will require all diesel engines to be at 0.20 grams per brake horsepower-hour (g/bhp-hr) of NOx, or oxides of nitrogen. Two methods that likely will be used to meet these new standards are classified as Exhaust Gas Recirculation (EGR) and Selective Catalytic Reduction (SCR).
The entire commercial vehicle industry utilized EGR to meet the first phase of the EPA’s 2007 emissions regulations. For 2010, North American bus customers will have two choices to be compliant; they can either buy an all-new, add-on after-treatment system using SCR in addition to EGR, which will be offered by most bus manufacturers. Or, they can continue to use an in-cylinder solution with advanced EGR, offered by Navistar in its IC Bus brand school and commercial buses.
Proponents of SCR, which uses the organic compound urea as the reductant, cite that its cheif benefit is that it enables the engine to run more efficiently at higher temperatures and generates a relatively lower amount of particulate matter. Yet, Navistar counters that SCR engines produce more NOx, which is very difficult to eliminate once it is formed.
To reach 0.20 g/bhp-hr, a mixture of 32.5 percent urea and 67.5 percent de-mineralized water is required. This mixture is marketed in the U.S. as diesel exhaust fluid (DEF). As European bus fleet operators know, the urea mixture, known as “AdBlue” in Europe, needs to be replenished frequently. “We feel that advanced EGR provides the best solution for our customers, both in terms of operator convenience and overall ownership costs,” says John McKinney, president and general manager, Global Bus Operations, at Navistar.
SCR takes place outside of the engine and, as a result, requires special software and an after-treatment system that comprises hundreds of pounds of added equipment to properly utilize urea. “That’s a lot of hardware to find a place for on our buses. We just don’t have a lot of room for it,” says Ed Hartung, director, IC Bus North American Operations.
SCR systems also have to contend with challenges presented by environmental temperatures. Urea freezes at 12 degrees F, requiring buses to be equipped with tank and line heaters. At low operating temperatures, the catalyst can clog. While urea does not require a hazardous materials (HAZMAT) handling certificate to haul, it does begin to decompose at 130 degrees F, resulting in ammonia emissions.
North American bus manufacturers opting for SCR tell customers that it improves fuel economy, has no effect on service and oil change intervals, that a urea distribution network is being established, and not to worry about its price because widespread use of SCR systems will only increase the total demand for urea by a few percent.
But, with SCR, it takes diesel fuel plus urea to get that improvement, and the greater the improvement in fuel economy, the more urea required, offsetting fuel economy gains. Urea may become widely available over time, but its price may be significantly higher where it is not available in bulk. “Bus operators will need to evaluate carefully their total operating costs and calculate their ‘miles per dollar,’ which takes into account the amount and cost of urea in addition to diesel fuel. Data that includes only traditional miles per gallon (MPG) of diesel is misleading,” says Randy Ray of Navistar Engine Group.
Navistar’s advanced EGR strategy is to prevent NOx from forming in the engine in the first place. This in-cylinder approach, in combination with higher EGR rates, is key to Navistar’s 2010 solution. They have eliminated the need for complex after-treatment hardware and procedures, simplifying the way for customers to achieve compliance. “This further adds to our ability to keep emissions compliance on our shoulders, while SCR puts the burden of compliance on bus fleet operators,” says McKinney.
So, how can Navistar achieve full compliance without after treatment? “Navistar has long planned for this level of emissions reduction, following a strategic path toward an in-cylinder solution for the past six years,” Ray says.
Four specific technologies enable Navistar to differentiate from the industry and offer what McKinney calls “a truly customer-focused solution:”
- Advanced Fuel injection technology;
- proprietary combustion bowl designs;
- advanced air-management systems; and
- proprietary electronic calibration strategies.
One of the keys to in-cylinder elimination of NOx is advanced high-pressure fuel injection. Not all engines can handle the necessary pressures. Navistar’s MaxxForce engine platforms, though, have been engineered for high structural strength, well ahead of 2010. Robust and durable block and head designs allow Navistar to achieve emissions compliance with an in-cylinder solution.
“This is proven technology that provides simplicity for customers,” adds Ray. With an in-cylinder solution, there is no need for any warehousing, storage or infrastructure changes, any extreme additions of external piping or storage tanks, or an additional operating fluid. Service technicians are already trained on EGR systems, unlike SCR, which will require maintenence and technician training to service the system and its additional components. And, with no additional external equipment, bus operators can continue to have available real estate on the chassis for under-carriage luggage, wheelchair lift and air conditioning system placement.
Furthermore, this idea of customer-focused simplicity extends beyond individual vehicles to fleet consistency. Just imagine, for example, the complexity of introducing 15 new 2010-model SCR buses into a fleet of 85 current 2007 EPA-compliant buses: two distinct maintenance routines, an additional procurement effort for urea (which includes an undetermined variable cost) and, if you are operating in a cold climate, two different operating procedures.
But as for offering a simple, proven path to 2010, it turns out Navistar is not the only engine manufacturer to choose an advanced EGR solution. Scania and MAN, two industry leaders in Europe and previously staunch defenders of SCR, are deviating from the SCR path and have recently confirmed plans to meet stricter European emissions standards through a non-SCR, enhanced EGR strategy. “We anticipate that many others will soon be reconsidering SCR,” McKinney adds.
This is the first article in a two-part series. Look for the next installment, “2010 Emissions Choices: Weighing Your Options” in a upcoming issue. We will also be featuring this on our blog after it is published.
Filed under: 2010 Emissions, IC, Metro Magazine, School Bus Fleet, Webinar
Metro Magazine and School Bus Fleet held their 2010 Emissions webinar today. It was sponsored by IC Bus, with Randall Ray and David Hillman as presentors.
The following issues were discussed: Emission Credits, Advanced EGR, EGR + SCR after-treatment system, EGR vs. SCR, and much more.
If you missed the webinar, you can replay or print it out here.
Filed under: 2010 Emissions, IC, Metro Magazine, School Bus Fleet, Webinar
IC Bus is presenting a customer webinar on 2010 emissions.
IC is once again working with School Bus Fleet and Metro Magazine to promote this educational opportunity.
HOW WILL YOU COMPLY WITH 2010 EMISSIONS STANDARDS?
Sign up for a FREE Web Event to find out your options and how they will impact your buses, employees and your bottom line.
February 4, 2009 | 10:00 AM
Filed under: Fuel Economy, IC, Metro Magazine, School Bus Fleet, Webinar
School Bus Fleet and Metro Magazine hosted a webinar sponsored by IC on Improving Bus Fuel Economy – Are your buses as fuel efficient as they could be? You can view this webinar at http://video.webcasts.com/events/bobi001/28426
Some interesting facts regarding fuel economy:
- At speeds greater than 55mph, each 1 mph increment in speed equates to .1 lost mpg!
- The fuel economy of a bus driven by your best driver compared to your worse driver can differ from 25-30%!
- One less gallon of diesel consumed equals 22 pounds of emissions reduced!
This webinar may take an hour of your time, but it can help reduce your fuel costs!
