System for rotationally securely plugging a sensor into a through passage of a flow channel

A sensor system for detecting an air mass flowing in a channel, comprising:

• a sensor device for rotationally securely plugging a sensor into a through-passage of a flow channel, including:
• a sensor arrangement including a sensor housing, the through-passage having an inner wall delimiting the through-passage, the through-passage having a first inside diameter extending along a first axis and a second inside diameter extending along a second axis which is perpendicular to the first axis, the first inside diameter being greater than the second inside diameter, the plug-in direction of the sensor housing into the through-passage defining a third axis which is essentially perpendicular to the first axis and the second axis, the sensor housing having a longitudinal extension area along the third axis, the longitudinal extension area having an outer wall, the sensor housing being pluggable into the through-passage;
• wherein at least one protrusion projecting inwardly into the through-passage by a defined dimension is provided on the inner wall of the through-passage, and/or at least one protrusion projecting outwardly by a defined dimension is provided on the outer wall of the longitudinal extension area of the sensor housing so that the sensor housing, in the plugged-in state, is rotatable in the through-passage by no more than 0.5° about the z-axis.