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Tier 4A Engine Technology: An Overview

Each month, I’ll introduce a Case IH expert to be our Be Ready guest blogger. I’ve invited Leo Bose as our first expert blogger, to discuss Tier 4A engine technology, facts or fiction. Leo is the training manager for Case IH and is responsible for developing the North American training strategy. He has been with Case IH for more than 16 years, serving in various positions, including combine marketing manager, training specialist on harvesting and planting equipment, training specialist on tractors and product support specialist on under-100 horsepower tractors. He also hails from a farm background!

Be sure to ask questions and we’ll help get the information you need to make informed decisions about Tier 4A.

From their invention more than a century ago, today’s diesel engines have evolved into more powerful and fuel-efficient engines. While that’s a good thing, their high emissions are bad for the environment.

Emissions occur during the combustion process, where impurities within the diesel fuel release toxic substances, such as carbon monoxide, hydrocarbons, nitrogen oxides, and particulate matter, with the latter two being the most targeted pollutants. Particulate matter is created by incomplete combustion at lower combustion temperatures, and nitrogen oxides are produced at high combustion temperatures and pressures.

Since 1980, nitrogen oxides and particulate matter emissions have been reduced by more than 90 percent. However, emissions levels are still too high.

In 1996, the United States Environmental Protection Agency (EPA), Canadian Environmental Protection Agency (CEPA), and European Union (EU) set the first emissions targets for off-road diesel engines to help minimize emissions. Since then, the EPA has implemented a two-stage approach known as Tier 4A and Tier 4B to further reduce nitrogen oxides and particulate matter, starting in January of 2011 with Tier 4A and ending in 2014 with Tier 4B as the final emissions mandate. Tier 4B requires a 90 percent reduction in particulate matter and nitrogen oxides over today’s current Tier 3 regulations.

While Tier 3 emissions regulations could be met by altering engine fuel calibrations or timing, Tier 4 emissions regulations require the addition of an exhaust after-treatment system.

The two after-treatment solutions that meet these stringent Tier 4 standards include Selective Catalytic Reduction (SCR) and Cooled Exhaust Gas Recirculation (CEGR).

About SCR Technology
In SCR, the combustion temperature is increased to reduce particulate matter, which results in the formation of more nitrogen oxide. To reduce nitrogen oxide, engine exhaust passes through the catalytic chamber, where it is variably dosed with a non-toxic, colorless, odorless mixture of chemical urea and purified water, known as diesel exhaust fluid (DEF). When the mixture combines with the hot exhaust in the catalytic chamber, it is broken down into simple chemical properties of water vapor and nitrogen.

SCR technology operates separately from the main engine function and does not compromise the combustion process. This ultimately enhances engine horsepower torque and overall engine performance. What farmer doesn’t want that? 

About CEGR Technology
In CEGR, outside air is mixed with measured amounts of exhaust gas to lower the engine’s peak combustion temperature, which reduces nitrogen oxide. 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”.

Now the battle is on over which after-treatment solution will provide you with the best performance, cost efficiency, and environmental care. Read Fact or Fiction to help you decide.

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  • Anne1.22.2011 Reply

    What will it take to get you engines to Tier IV B?

    • CASE IH1.24.2011

      In 2014, Tier 4B standard will take effect for high horsepower diesel engines. The new Tier 4B standard requires a further reduction in NOx. Case IH has not announced their Tier 4B strategy, since Tier 4A just came into effect. Case IH will continue to use SCR technology for Tier 4B along with most diesel engine manufacturers. With that being said, the current SCR system will not meet the Tier 4B standard so there will be slight modifications. For Tier 4B, Case IH will continue to deliver the industry leading horsepower and fuel savings that the current SCR system delivers.

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