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School of Hard NOx: SCR Primer

By now, you’ve probably heard about the new federal regulations mandating cleaner, more efficient engines beginning in 2011. Maybe you’ve even heard some acronyms like SCR and CEGR and wondered what it means to you.

Listen up, class is in session!

Tier 4 emissions regulation was created to crack down on air pollutants – primarily particulate matter, which we know as soot, or unburned fuel, and nitrogen oxides (NOx) emitted as a by-product of an engine’s internal combustion process. Doing this requires the addition of an exhaust after-treatment system, such as Cooled Exhaust Gas Regeneration (CEGR) or Selective Catalytic Reduction (SCR). 

SCR is a simple system being employed by Case IH for 100+ horsepower tractors that maximizes engine power and fuel economy by treating exhaust gases with a second fluid to eliminate pollutants as they leave the tractor through the exhaust stack. Engine exhaust passes through the catalytic chamber, where it is sprayed with a second fluid, called diesel exhaust fluid (DEF). When DEF combines with hot exhaust, it breaks down the exhaust into simple water vapor and nitrogen – harmless, non-polluting components of the air we breathe.

CEGR, which is the technology supporting many competitors’ over 100 horsepower tractors, mixes outside air with measured amounts of exhaust gas to lower the engine’s peak combustion temperature and reduce nitrogen oxides. Due to lower combustion temperatures, an increase in particulate matter occurs. This particulate matter is captured by a diesel  exhaust filter which incorporates a catalyst that helps burn the soot particles when there is sufficient heat in the exhaust for the catalyst to be activated. The DPF traps particulates, which are then “burned off”.

Case IH has discovered that in addition to minimizing air pollutants, SCR also improves engine performance and productivity. Engines with SCR are tuned to deliver maximum horsepower without compromising efficiency to manage emissions, resulting in increased performance. Eliminating exhaust gas recirculation in the combustion process will enhance fuel efficiency, while also increasing reliability and durability and extending maintenance intervals.

Case IH will utilize SCR for engines with over 100 horsepower, as it provides an enhanced solution for high horsepower applications, which often require engines to run consistently at near 100 percent load. By avoiding the need to bring hot exhaust gas back into the combustion process, an SCR-equipped engine is able to rely on cool, clean intake air, which is ideally suited for such demanding situations. We also know that high horsepower applications involve high rates of fuel, so improved fuel efficiency improves your bottom line more rapidly. Do I have your attention yet?

Now, I know you’re thinking – “But it requires an additional fluid to do all that! What’s this extra step going to cost me in the long run?”

DEF fill is an easy part of your regular daily maintenance routine. The Case IH DEF tank is located on the same side as the fuel tank fill, so as long as you know how to fill a fuel tank, you’re set! Simply top off your DEF tank when you top off your diesel fuel. The DEF fill neck is designed so that only a DEF fill nozzle can be inserted for filling. This will prevent operators from inadvertently adding diesel to the DEF tank. Your tank only needs to be filled after every other fuel fill-up. And, DEF’s price per gallon is in-line with that of diesel fuel.

Even when accounting for DEF consumption as an operating cost (fluid efficiency), tests show that Case IH equipment with SCR reduces total operating costs by a minimum of 10 percent. While it’s true that you’ll be handling another fluid on your farm, Case IH chose SCR because of the significant savings in terms of fuel costs and reduced maintenance requirements that it provides customers, and because SCR technology provides the most feasible path for future emission standards for high horsepower applications.  After accounting for true “fluid efficiency” including the impact of both DEF fluid consumption, along with fewer oil changes and improved fuel efficiency, new SCR-equipped Case IH tractors accomplish 10 percent less operating cost.

As of January 1, 2011 all new Case IH tractors with 100+ horsepower will feature SCR. In combination with proven Case IH engine designs, SCR technology will improve engine power and responsiveness, fuel economy, and overall durability for Case IH Steiger®, Magnum™ , and Puma™ tractors, while helping them meet 2011 EPA emissions regulations.

Any questions?

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  • ismail1.7.2011 Reply

    What will happen to Tier 3 tractors, new technology applied to old?

    • CASE IH1.11.2011

      Tier 3 Case IH engines are fully compliant under the Tier 3 EPA regulations. At this time, Case IH does not have plans to retro fit Tier 4 emission components on Tier 3 engines. However, if market demand increases for this type of activity, Case IH will look into the possibility of retrofitting.

  • Smith Agro Ltd.3.17.2014 Reply

    We continue to have trouble with SCR failure on our 500 and 600 quad tracks. We farm in Saskatchewan, Canada. We have dozers on both tractors for snow plowing in the winter. How do you suggest we operate these tractors when it is -40 degrees Celsius and def is 80% water and the tractors are a outside plugged in?

    • Case IH4.9.2014

      Please contact your local Case IH dealer. They can answer any questions about DEF you may have.

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