Meeting EPA Standards With SCR Technology

With more and more emphasis placed on environmental conservation and reducing greenhouse gases, the trucking industry was a large factor in the EPA’s decision to tighten up emission standards in 2010.

Since then, heavy truck manufacturers have had to adjust production models to reduce the amount of exhaust being created, which was not an easy thing to do.

Two methods for making such a change exist – Selective Catalytic Reduction (SCR) and Extreme Exhaust Gas Recirculation (EGR), although each leaves its own questions on the performance and efficiency of heavy commercial vehicles.

semi truck

One of the leading heavy truck manufacturers decided to use SCR technology – and so far it has been a great decision.

Increasing Heavy Truck EPA Standards

Raising emissions standards on all freight shipping vehicles is a good environmental decision; however, some truck makers have anticipated problems in meeting such requirements while maintaining fuel efficiency.

Free-flowing, unrestricted exhausts will always allow for greater vehicle capability; when filters and other things are attached to handle exhaust, efficiency can go down.

Keeping Efficiency

Trucking companies have implemented Selective Catalytic Reduction (SCR) technology without disrupting diesel engine fuel efficiency while still meeting EPA requirements.

As a matter of fact, these vehicles met the projected 2013 EPA requirements in 2010, indicating the achievement of a good emissions-control system for the trucks. Instead of negatively affecting fuel efficiency, it has increased fuel performance and torque, which has made such a changeover better for the company.

SCR Technology Function

SCR has proven to be the leading idea in reduced emissions controls for vehicles of all sizes – and the simplest method by far. Requiring the addition of only a few exhaust parts, this modification can be quickly made; other methods like Extreme Exhaust Gas Recirculation (EGR) requires replacing the stock motor with a larger, stronger one.

SCR works just as well if not better and is very cost-effective.


The SCR system adds fluid to the exhaust and filters it, leaving the vehicle as water and nitrogen. Trucks are equipped with a Detroit or Cummins Diesel EGR engine, a diesel oxidation catalyst, and a particle filter that cleans out particles, soot and other solids coming through the system and is mixed with a vapor of diesel exhaust fluid from an in-line DEF reservoir.

The exhaust is filtered once more through an SCR catalyst filter, leaving an exhaust that is water and nitrogen.

SCR Effect on the Commercial Vehicle Market

When the new EPA requirements and projected upgrades were announced, truck manufacturers and buyers alike expressed some concerns. Since available technology at the time did not seem promising for maintaining fuel efficiency and engine power, it could have been a huge blow to the trucking industry leading to higher costs.

There was concern about how much new equipment would have to be installed and where it would be placed. The purchasing of new vehicles with this technology slowed to see how it would all work out.

Few Problems

With companies doing so well with SCR emissions systems, the hesitancy to buy commercial vehicles with such a system is fading. There has proven to be few problems and the trucks have continually out-performed the necessary requirements, which is a good investment as far as EPA compliance goes.

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