The invention relates to an engine auxiliary drive for a motor vehicle with a toothed-gear drive, comprising a first (1) and a second gear wheel (2) with teeth flanks (11, 12), engaged with each other, whereby the teeth flanks (11, 12) on the gear wheels (1, 2) in the force transmission region (13) are embodied without involute and progress directly or almost directly from a concave region into a convex region and the first gear wheel (1) is made from plastic.