Method and device for recognizing a water passage by means of distance sensors

Abstract

The invention relates to a method and to a device, in particular a control and evaluation unit, for recognizing a water passage or a high water level for a vehicle, which has, as a drive, an internal combustion engine having an exhaust train, in which the functionality of an emission control system is monitored or controlled by at least one exhaust sensor and the exhaust sensor is operated at least intermittently at high temperatures and has thermal shock susceptibility by design. According to the invention, a water recognition criterion is determined based on one or a plurality of distance sensors and, at critical values of the water level which are predicted or have already been reached, protective measures are initiated for the emissions control system of the vehicle or for the exhaust sensor or exhaust sensors arranged in the exhaust duct. Damage to exhaust sensors or to components of the emissions control system as a result of the severe cooling upon contact with water can thus be minimized. In addition, misinformation of the exhaust sensors due to a thermal shock and a possible accompanying malfunction can also be recognized by said anticipatory protective measures and correspondingly suppressed.