PEORIA, Ill. — Caterpillar has cautioned the industry that Selective Catalytic Reduction (SCR) may not be the best solution available to meet 2010 emissions standards.

While the engine manufacturer admits SCR is viable, it has issued a statement saying "At Caterpillar, we urge the on-highway market to keep the technology options open regarding 2010 emissions. Several engine manufacturers have indicated that SCR is the only viable path for meeting the 2010 EPA standard -however, our research indicates SCR might not be the best choice for on-highway applications."

Cat adopted its own ACERT technology to meet 2002 emissions standards and it plans to use the same technology in 2007. The company is already working towards meeting 2010 emissions standards using engine combustion technology.

John Campbell, general manager of engineering for Cat’s Large Power Systems Division, says the company already has engines running in test labs that are 2010-compliant without the use of SCR. Cat has also established an Environmental Technologies Group to work on various aftertreatment solutions in the area of diesel particulate filters and NOx aftertreatment.

"As was the case with ACERT Technology, our engineering team is working toward a “system solution” that combines combustion technologies, fuel system technologies, electronics and aftertreatment to meet the 2010 EPA standards while providing customers with the same reliability, durability, operating cost and fuel economy as today," Cat officials recently announced. "This type of technology solution eliminates some of the concerns regulators have regarding monitoring compliance with SCR – specifically, the regular addition of urea to special tanks on the vehicle. Campbell has indicated that a systems approach can provide customers with on-highway engines that meet emissions while delivering the operating cost they need to be profitable."

Cat has used SCR in the past for its electric power generation, however, officials say while it’s ideal for stationary applications SCR is probably not the best technology for mobile applications such as on-highway trucks. Having said that, Cat will continue to research SCR as a possible 2010 solution while also exploring other alternatives.

James Parker, vice-president of Caterpillar Power Systems Marketing, says several key issues remain unresolved when it comes to SCR. For instance regulating the urea usage will be a challenge. Also, the infrastructure must be built within a "logistically complicated North American market."

Caterpillar is also concerned that the cost benefits of SCR may not be as good as originally expected, based on the European experience. Another key concern is the weight of the urea tank and the system’s vulnerability to external damage.

"At Caterpillar, we believe it is critical for the industry to explore all possible technology options before coming to conclusions about any single solution," Parker says.