A handful of Volkswagen consumers who opted out of the "clean diesel" class action settlements have filed a motion to disqualify U.S. District Judge Charles Breyer from next week's trial.

In a Wednesday motion, lawyers for 10 plaintiffs suing Volkswagen for fraud damages said that the Northern District of California judge had raised "concerns about appearance of bias" after he ruled this month to make the trial's first phase a bench trial focused on the fairness of the "clean diesel" settlements, the same ones that he approved.

That first phase starts Monday.