Patent ID: 8612119

Claim:
Method to control an internal combustion engine fueled by a fuel blend of a diesel fuel and a biodiesel fuel and equipped with a lean NOx trap for treating an exhaust gas flow from the engine, the method comprising: providing a feed forward fuel control term corresponding to a fuel blend of 100 percent diesel fuel and 0 percent biodiesel fuel; providing a feedback fuel control term as a function of a deviation in the engine air fuel ratio from an air fuel ratio target; during engine operation wherein said lean NOx trap is not being regenerated, providing a final fuel control term as function of the feed forward fuel control term and the feedback fuel control term; during engine operation wherein said lean NOx trap is being regenerated, providing a feed forward adaptation factor as a function of the feed forward fuel control term and the final fuel control term, applying the feed forward adaptation factor to the feed forward fuel control term to provide an adapted feed forward fuel control term, and providing the final fuel control term as a function of the adapted feed forward fuel control term and the feedback fuel control term; and fueling the engine in accordance with the final fuel control term.