ALTHOUGH the Cummins next-generation QSB diesel engine doesn't look much different from its predecessor on the outside, the company says the new powerplant features an “in-cylinder” emissions solution that has enabled increased performance while meeting more stringent Tier 3 emissions regulations. By focusing on more efficient combustion in the cylinder, Cummins engineers were able to do without the use of complex turbocharger arrangements or external hardware such as exhaust gas recirculation.

The QSB features increased displacement, rear gear drive, a high-pressure common-rail fuel system and other enhancements for performance, durability and reduced noise. These engines not only meet the EPA Tier 3 emissions requirements, but are fully capable of moving forward to the future Tier 4 requirements.

The Tier 3 QSB will be available in both a 4- and 6-cyl. platform, with displacement increased from 3.9 to 4.5 liters and from 5.9 to 6.7 liters compared to the current Tier 2 QSB. The engines are rated from 110 to 275 hp and are specifically designed to meet the durability, reliability and power-density requirements of applications such as tractors, sprayers and combines.

Cummins began limited production of the 6.7-liter QSB, rated at 135 to 275 hp, in June 2005, a full six months ahead of the emissions regulations. The 4.5-liter QSB, rated at 110 to 170 hp, will be in limited production in December 2005, a full year ahead of the regulations. The 4.5-liter QSB has been increased from 130 to 170 hp from the Tier 2 engine.

For more information, visit www.cummins.com.