Navistar International Corp. announced this afternoon that yesterday it resolved its lawsuit filed last summer against the U.S. Environmental Protection Agency (EPA). The resolution came by way of reaching an agreement in which EPA “promised to hold a public workshop or hearing to address issues Navistar raised in its federal court appeal of EPA’s certification policies for SCR-equipped diesel powered trucks.”

The truck and engine maker said it had asked the U.S. Court of Appeals in Washington, DC to void those polices “because they had been adopted by the EPA without the public process required by law, but instead following input only from the SCR engine makers.”

In its appeal, Navistar charged that EPA is using those policies to allow SCR- equipped diesel powered trucks to operate for extended periods without any control of NOx emissions and is certifying SCR engines as meeting NOx emission requirements when they do not.

According to Navistar, the agreement provides that EPA will “engage in a public process to reexamine its policies, for future 2011 and later model year engines” during which it will “provide a thorough review of EPA's policies regarding operation of SCR-equipped engines”. The company said that EPA also has promised to “ensure, among other things, that SCR equipped heavy duty diesel engines are designed to properly control emissions as required under applicable regulations.”

“We are pleased with this agreement and look forward to participating in the public process,” said Jack Allen, president of Navistar’s North American Truck Group. “We believe that with full and open public participation, EPA will develop a new approach that will result in equal enforcement of the 2010 NOx requirements for all engine makers.”

In March, Navistar noted, its MaxxForce DT mid-range diesel engines and MaxxForce 13 big-bore diesel engines were certified by EPA for model year 2010.

The agreement must be published by EPA in the Federal Register for comment before it can become final.

Almost two weeks ago, Navistar resolved a similar lawsuit it had filed against the California Air Resources Board (CARB). That suit had alleged that CARB was improperly certifying 2010 diesel engines equipped with SCR aftertreatment systems to control emissions of oxides of nitrogen (NOx).