Columbus, Ind. (May 3, 2005) - Cummins Inc. (NYSE:CMI), working with the U.S. Department of Energy (DOE), announced significant progress toward meeting engine efficiency and emissions targets as part of the government/industry 21ST Century Truck Partnership with the truck and bus industry. Cummins has demonstrated an ISX heavy- duty truck engine with an increased Brake Thermal Efficiency (BTE) of 45% while reducing emissions to levels associated with the future introduction of 2007 technology. Particulate Matter emissions were reduced to 0.01 gram/hp-hr by utilizing a Cummins Particulate Filter, while oxides of nitrogen were lowered to 1.2 gram/hp-hr using in-cylinder combustion control.

The work provides a foundation for the further development of engines capable of meeting EPA 2007/10 emissions. Current heavy-duty engines meeting the EPA 2002 regulation typically achieve a BTE level of 41%. Brake Thermal Efficiency represents in percentage terms the amount of energy converted from diesel fuel into useful mechanical work by the engine. By increasing the BTE level, the engine becomes more efficient and offers the potential for increased fuel efficiency by a near equivalent percentage. Coincidentally, achieving higher fuel efficiency also results in reduced CO2 greenhouse gas emissions from the engine.

Commenting on Cummins contribution to the program, Edward J. Wall, head of DOE's FreedomCAR and Vehicle Technologies Office, from the Department of Energy said, "Heavy-duty truck diesels represent the most energy-efficient power unit we have on the road today for moving goods or passengers. As part of this program between government and industry, Cummins has successfully demonstrated that the heavy-duty engine has the potential for even higher levels of efficiency while still meeting stringent emissions requirements. Looking ahead, this offers the opportunity for our trucks and buses to reduce fuel consumption and help reduce the nation's dependency on imported oil."

The 21st Century Truck Partnership between government and industry was initiated in April 2001 with the key aim of achieving a ten-fold reduction in engine emissions combined with a substantial increase in engine efficiency. The DOE leads a federal multi-agency mission to reduce dependence on imported oil and improve the nation's air quality. Cummins, along with other industry participants, has worked in close cooperation with the DOE to set ambitious program targets through 2012.

"We have achieved some impressive technology advances to meet the initial engine efficiency and emissions deliverables of the program. Now we are moving ahead to achieve an even higher 50% BTE target with NOx emissions at a lower level of 0.2 g/hp-hr," commented Christine Vujovich, Cummins Vice President - Marketing and Environmental Policy.

"A key program driver for Cummins is to ensure that these technical advances are commercially viable and minimize the impact on OEM vehicle installation. The Department of Energy provided an invaluable level of cooperation throughout the program. It demonstrates just how much can be achieved when federal agencies and industry work together toward a common goal in the best interest of the nation's environment and energy security," added Vujovich.

Note to Editors: Cummins will participate in the SAE Government/Industry meeting (Washington D.C., May 9-10, 2005) focused on new automotive technology for energy conservation and the environment.

Cummins Inc., a global power leader, is a corporation of complementary business units that design, manufacture, distribute and service engines and related technologies, including fuel systems, controls, air handling, filtration, emission solutions and electrical power generation systems. Headquartered in Columbus, Indiana (USA), Cummins serves customers in more than 160 countries through its network of 550 company-owned and independent distributor facilities and more than 5,000 dealer locations. With more than 28,000 employees worldwide, Cummins reported sales of $8.4 billion in 2004.