Apr 26, 2010 10:12 AM

Navistar International Corporation has withdrawn a lawsuit it previously filed against the California Air Resources Board (CARB) after an agreement with CARB that addresses the issues that prompted the court action.

Navistar had sought a ruling in a San Francisco Superior Court declaring that CARB was improperly certifying 2010 diesel engines equipped with an aftertreatment system called SCR, which is used to control emissions of oxides of nitrogen (NOx). The lawsuit charged that CARB was applying certification requirements that permitted SCR-equipped diesel-powered trucks to operate for extended periods without any control of NOx emissions.

The requirements were contained in USEPA 2009 guidance documents that the lawsuit also charged had been adopted by CARB. A separate court action challenging USEPA’s 2009 guidance is still pending in Washington DC. In its lawsuit against CARB, the company charged, “The 2009 Guidance allows engines to operate for multiple and lengthy periods of time with the NOx emission control SCR Systems turned off, causing uncontrolled NOx to be discharged into the air.” The company asked the court to declare that CARB’s adoption of the 2009 guidance was null and void.

Navistar dismissed its lawsuit after reaching an agreement with CARB in which CARB agreed that the 2009 guidance documents are not its policy. CARB also agreed to convene a public workshop no later than August to address the issues Navistar raised. Navistar expects the workshop to produce an outcome that will eliminate the opportunity for SCR-equipped trucks to operate with uncontrolled NOx emissions for multiple and lengthy periods of time.

Earlier in April, Navistar’s MaxxForce DT mid-range diesel engines and MaxxForce 13 big-bore diesel engines were certified by CARB for model year 2010.