Investigation of the Effectiveness of a Passive Device for Soiling Mitigation for Vehicle Side-Cameras 2020-01-0699
The development of modern autonomous automotive technology depends heavily on the reliable performance of external sensors that are vulnerable to soiling. Existing active cleaning devices, such as washers and wipers, are relatively complex, expensive or unsuitable. Furthermore, little research has been done on alternative soiling mitigation strategies and devices for sensors. With the emerging trend to replace side-mirrors with camera monitor systems, it is important for such systems to stay clean even in adverse weather in order to provide critical navigation information. To meet this need, a passive aerodynamics-based cleaning device was investigated. A converging vent device was integrated into the side-camera housing and the subsequent degree of soiling was estimated at wind speeds of 15, 20, and 25 m/s (representing city and country driving speeds). The vent outlet width, outlet jet angle, and outlet jet velocity of the vent device were varied and the variants were compared to the non-vented reference model. The degree of soiling was evaluated computationally and experimentally. A single phase simulation was performed using ANSYS® Fluent where the degree of soiling was estimated based on momentum fluxes. Several selected variants were 3D-printed and sprayed with water in wind tunnel tests, where the degree of soiling was quantified by water droplet counts. The results from both the CFD and wind tunnel tests suggest that the vent device is effective in reducing soiling for up to 65%. This investigation demonstrated that the outlet geometry of a passive vent device significantly affects the deposition aerodynamics and the type of soiling on a sensor and provided insight for further design and development of such devices.
William Collings, Wing Yi Pao, Martin Agelin-chaab