A motor vehicle undertray trim panel having an air inlet delimited toward the vehicle and toward the roadway by upper and lower flat elements, respectively, which extend arcuately rearward and upward in the direction of a vehicle engine compartment for air flow cooling. The rear end of the upper flat element is adjoined by a planar air ram plate which runs by a small amount substantially vertically upward, and ends substantially freely in the engine compartment. The air inlet contains eddy producing structures. The structures may be a plurality of air guiding plates which extend along the vehicle vertical axis and the vehicle longitudinal direction in the air inlet and which are curved transversely such that the overall flow cross section in the vehicle longitudinal direction is substantially constant, or a plurality of small air inlets which are integrated into the air inlet.