Tier 4 EPA Compliant Engines; The Who, What & When
Engines used in virtually every piece of heavy construction equipment is changing as the U.S. Environmental Protection Agency’s (EPA) Jan. 1, 2011, deadline approaches for Tier 4 Interim (Tier 4i) compliance on engines of more than 130kW (174 hp).

What does this mean for you and how will it affect your business and equipment use? We will defer to our friends over at Rental Management who put together an article written by Jim Robinson to try to help clear the mud.
Engine manufacturers have spent the past several years developing new technologies to meet the new mandates and many have introduced Tier 4i/Stage IIIB compliant engines, a step to a final Tier 4 level requiring that engines emit 90 percent less particulate matter (PM) and 50 percent less nitrogen oxides (NOx) than Tier 3 engines.
There are two main technologies that engine manufacturers have adopted to reach Tier 4i compliance.
One of the technologies used by manufacturers is selective catalytic reduction (SCR). When an engine is adjusted for maximum efficiency, high combustion temperatures will reduce PM levels but increase NOx levels. SCR is an after-treatment system that cinjects diesel exhaust fluid (DEF), a mixture of urea — an organic compound — and water into the exhaust stream to create a chemical reaction that transforms the NOx into nitrogen and water.
Manufacturers in favor of using SCR say that because the combustion process on an SCR engine is efficient, the fuel consumption is reduced and the after-treatment system allows the engine to be very high performance. They say the simple design of the SCR system allows it to be very efficient and provide the same torque and power at the same displacement, which critics of cooled exhaust gas recirculation (CEGR) say is not possible with that technology.
The second major technology used to reach Tier 4i compliance is cooled exhaust gas recirculation (CEGR), which is a method for reducing NOx levels. A CEGR system recirculates exhaust gases, blends them with fresh air and returns the blend to the cylinder. This makes for lower combustion temperatures, which reduces NOx, but also will mean higher PM levels than those produced by a hotter burning engine. That means an after-treatment exhaust filter system is needed to lower the PM levels. This particulate filter is coated with a catalyst so that hot exhaust can burn off particulate matter, releasing carbon dioxide.
With a CEGR system the basic engine technology remains the same, there is no additive required and the system doesn’t require any change in the way the equipment is operated, but the particulate filter will require attention. “The CEGR system’s diesel particulate filter requires periodic regeneration that will vary depending on engine load. The filter offers a long life — more than 1,000 hours — but requires eventual replacement,” says Case’s Stemper.
How much can you expect equipment costs to go up or change with Tier 4 regulations?
When the EPA developed the Tier 4 regulations, it estimated the increase would be 1 to 3 percent of the total equipment price, so the cost of a $13,000 piece of equipment would rise by $760 and the cost of a $235,000 piece would rise by $2,590. Caterpillar recently announced that prices on its equipment would increase by 2 to 6 percent next year in order to pay for the development and production of the new emissions technologies.
Full Article from RentalManagementmag.com: What Tier 4 Means To You











