Cummins Inc., Columbus, Ind. (www.cummins.com), is on track toward meeting Environmental Protection Agency (EPA) Tier 3 diesel-engine standards that take effect in January 2005.

The company is upgrading its entire product line, from 50 to 750 hp, with the goal of high reliability and performance and low operating cost, while meeting or exceeding clean-air standards, says Tom Kieffer, executive director, marketing.

Cummins tweaked the in-cylinder combustion process to meet Tier 3 NOx (nitrogen oxides) levels without aftertreatment systems or other hardware. A common-rail fuel system and full electronic control over fuel-injection timing, quantity, pressure, delivery rate shape, and the number of injections minimizes emissions. Because the engines feature an in-cylinder emission solution, rather than external hardware, impact on OEMs is expected to be minimal. And the engines will meet Tier 3 emissions levels even with high sulfur fuels, permitting operation anywhere in the world.

The company is also investing in meeting new Tier 4 regulations scheduled to take effect beginning in 2008, says Christine Vujovich, vice president of marketing and environmental policy. This will demand cleaner engine combustion combined with high-efficiency aftertreatment, she says. The intent is to develop fully integrated engine and emission reduction systems as a single, complete package.

The company plans to apply Tier 4 technology to the latest Tier 3 engine platforms. This commonality will reportedly offer OEMs a significant advantage by minimizing installation changes through 2014.

The EPA's emissions rules will be phased in according to engine power bands, requiring varying levels of emissions reduction. Engines rated below 49 hp must comply by 2008. The most-severe emission reduction levels will apply to engines rated over 50 hp beginning in 2011 with Tier 4 Interim, followed by Tier 4 final beginning in 2014. This will reduce NOx and particulate matter emissions by over 90%. The regulations cover all diesel-powered construction, agricultural, mining, and other off-road machinery. A key part of the Tier 4 rule, says Cummins, is the regulated reduction of sulfur content in off-road diesel fuel from over 3,000 parts per million (ppm) to the first 500 ppm and then 15 ppm just ahead of the interim and final engine emissions effect dates. This will make it possible for engine manufacturers to comply with the EPA standards.