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July 18, 2011 6:00 AM, EDT

By Eric Miller, Staff Reporter

This story appears in the July 18 print edition of Transport Topics.

Navistar Inc. has formally resumed its battle with the U.S. Environmental Protection Agency, filing a second federal lawsuit to block the agency’s recently updated guidance for certification of heavy-duty truck engines using selective catalytic reduction technology to reduce emissions.

The lawsuit, filed in the U.S. District Court for the District of Columbia, alleges that SCR’s urea-based engine technology can be defeated easily, allowing trucks to run thousands of miles with empty diesel exhaust fluid tanks.

“EPA has turned a willful blind eye to SCR non-compliance,” Navistar said in the lawsuit. “EPA has favored liquid, urea-based SCR systems for no environmental purpose, but rather for unlawful anti-competitive reasons — namely to make SCR engines more user-friendly so that they can compete more easily and unfairly against other engines, including Navistar’s.”

Navistar filed the lawsuit July 5, more than a year after the company dropped a similar lawsuit after reaching a settlement agreement with EPA.

The lawsuit alleges that EPA Administrator Lisa Jackson failed to require testing of the SCR engines under “actual current driving conditions,” including engines running on empty DEF tanks, with water instead of DEF, frozen DEF or at low engine-exhaust operating temperatures.

Navistar spokesman Steve Schrier declined to elaborate on the lawsuit but said the action was taken to “seek a level playing field.”

EPA did not return a phone message seeking comment by press time.

The agency’s most recent SCR guidance, issued in June, was an update to guidance memos issued in 2007 and 2009. It rejected Navistar’s longstanding claims that SCR technology can be defeated easily, but it urged SCR engine manufacturers to continue improving warning systems that alert drivers when a truck’s DEF is low, empty or filled with an “incorrect or poor-quality agent.”

DEF, a urea-water solution, is an essential component of SCR, enabling the system’s catalytic converter to remove nitrogen oxides from exhaust.

While Navistar’s engines are using exhaust gas recirculation technology to meet 2010 emission standards, all other competitors are using SCR technology.

In a 31-page public comment letter filed on July 7, Navistar called the new guidance a “step backward” that “serves no legitimate regulatory or environmental purpose.”

The other engine makers filed written comments with EPA that largely supported the agency’s new guidance.

EPA said it will review the public comments and provide final guidance and interpretations in a future Federal Register notice.

The Engine Manufacturers Association agreed with EPA that, so far, SCR systems have been successful in inducing operators to refill DEF tanks on a timely basis and to avoid tampering with SCR operation.

American Trucking Associations cautioned that the new guidelines might be going too far in imposing even more stringent, severe inducements. The guidelines require that when its DEF storage tanks are empty of SCR or when systems are not operating correctly, a vehicle’s maximum speed must be reduced gradually at a safe rate to 5 miles per hour.

“Triggering a severe inducement likely will result in a significant economic penalty for a motor carrier, as additional drivers and trucks may need to be dispatched to complete delivery and customers may refuse to pay the freight bill associated with a delayed delivery,” ATA said.

EMA said manufacturers must be afforded adequate lead time to implement any changes in regulatory requirements, certification or compliance protocols.

EMA did not agree with EPA’s expectations that urea quality sensors will be available for use in 2013 model-year vehicles, “or whether, if available, they will be necessary.”

Daimler Trucks North America and its Detroit Diesel Corp. unit also questioned whether a DEF quality sensor will be developed by 2013.

“It is possible that, one day, diesel exhaust fluid will be like fuel; a vehicle will not operate without it,” the firms said. “However, we must make sure that the steps we take are in the best interest of all highway users, including that they do not strand vehicles and cause safety or traffic concerns, especially not for occurrences that are no fault of the driver.”

Last year, Navistar said an independent study it commissioned showed that SCR trucks could run even when their DEF reservoirs are empty or filled with tap water (7-26-10, p. 1).

But comments filed by Volvo Group North America LLC and Mack Trucks Inc. said the Navistar study is of “limited or no value” because it was based on an analysis of inducement systems on only three engines.

Testing to date demonstrates that inducement strategies used by SCR engine manufacturers were “more than sufficient” to ensure consistent, proper use of DEF, Volvo and Mack said. “As the available evidence shows, vehicle operators simply are not going to the great and costly lengths necessary to circumvent using DEF.”