Abstract
Accumulation of atmospheric icing, particularly wet snow, on the visual sensors/navigators of autonomous vehicles (AVs) increases the possibility of accidents by obstructing the lenses of the sensors. Here, two navigator designs were suggested that use airflow across the lens surfaces of the AVs to prevent snow accumulation on them. The impact of airflow intensity across the lens, wind velocity (relative velocity of wind with respect to vehicle), and liquid water content of snow on prevention of snow accumulation on the lenses of the AVs was explored experimentally. Here, artificial snow grains were formed using a novel snow gun and their average sizes at low liquid water content (LWC of ≈ 8%) and high liquid water content (LWC of ≈ 28%) were measured to study the impact of grain sizes on snow accumulation on camera lenses. The effects of wind velocity, snow density, and diameter of the snow grains on their trajectory in the testing section were also studied numerically. The results indicated that the snow grains with higher velocity, density, or diameter possessed higher inertia forces and were more prone to collide with the navigator, increasing collision efficiency of snow grains. We realized that the airflow across the lens effectively prevented snow accumulation on the lens at vehicle/wind velocities of up to 20 mph. The proposed designs actively reduced the snow accumulation on the camera lens, promising to be applied in future AVs.Graphic abstract
Highlights
The technology of autonomous vehicles (AVs) due to offering mobility to the elder or disabled people, improving safety, saving fuel, reducing emissions, and increasing road capacity has attracted significant attention in recent years [1,2,3]
Snow is in so-called pendular regime, when the liquid water content (LWC) by mass is below ≈ 27% [51]
Since there is no water movement inside the snow layer in the pendular regime, it can be assumed that the LWC of an individual snow grain is approximately equal to the LWC of a snow layer
Summary
The technology of autonomous vehicles (AVs) due to offering mobility to the elder or disabled people, improving safety, saving fuel, reducing emissions, and increasing road capacity has attracted significant attention in recent years [1,2,3]. At LWC of > 20% the snow cohesion and adhesion strengths decrease, reducing the stickiness of snow grains to surfaces This is because of the domination of water in snow grains. To examine the effectiveness of each design, we created snow using a novel snow gun with controlled air/water ratio leading to snow grains with controlled density, size, and liquid water content (LWC). We studied snow accumulation on camera lenses of the AV systems at different relative velocities of wind with respect to vehicle (hereafter wind velocities) and snow LWC values, with and without using the airflow over the lens. To better understand the experimental observations, we conducted a numerical study to investigate the effects of velocity, density, and diameter of snow grains on collision efficiency of snow grains, directly impacting their accumulation.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
