Laminar Flow Sensor Cleaning for Curved Lenses
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Solution Overview
Problem
Vehicle sensors, particularly those with curved lenses, face challenges in cleaning due to the geometry of their design, which leads to inefficient liquid usage and incomplete debris removal when using turbulent flow, as the liquid often splashes away from the sensor without contacting the distal side, necessitating additional nozzles and increased complexity.
Innovation Solution
A cleaning system that utilizes a single nozzle to spray a liquid with laminar flow at a predetermined angle and distance, creating a boundary layer that covers the entire lens surface, ensuring effective debris removal without obstructing the sensor's field-of-view, by mounting the nozzle at a distance based on the lens's radius and fan angle, allowing the liquid to flow from the proximal to the distal end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If turbulent flow spray is used to clean the sensor lens, then debris removal is achieved, but liquid splashes away from the distal side and cleaning efficiency decreases
Solution Approach 1:
The patent changes the flow regime parameter from turbulent to laminar flow. By controlling the spray to produce laminar flow with a thin liquid boundary layer that adheres to the lens surface, the liquid follows the curvature of the lens to the distal side without splashing away, thereby improving cleaning efficiency and reducing liquid loss
Solution Approach 2:
The patent introduces a new dimensional parameter - the spray angle relative to the lens surface. By directing the spray at a specific angle that creates a tangential flow along the lens surface, the liquid coverage is optimized to reach the distal side while maintaining laminar flow characteristics
2Reliability
If additional nozzles are added to clean the distal side of the lens, then complete debris removal is achieved, but device complexity increases
Solution Approach 1:
The single nozzle is designed to perform multiple functions: it generates laminar flow that adheres to the lens surface and uses the lens's own curvature to direct the liquid flow to the distal side. This eliminates the need for separate nozzles for proximal and distal cleaning, reducing device complexity while maintaining complete debris removal
Solution Approach 2:
The laminar liquid boundary layer acts as an intermediary that transfers cleaning action from the proximal side to the distal side of the lens. The liquid flow serves as a medium that carries cleaning force along the lens surface, eliminating the need for direct nozzle contact with the distal side
3Area of stationary object
If nozzle is placed close to the sensor, then liquid coverage is improved, but field-of-view obstruction occurs
Solution Approach 1:
The patent positions the nozzle in a specific spatial relationship to the lens, using the lens radius and fan angle to determine optimal placement. The spray is directed at an angle that creates a tangential flow, allowing the liquid to cover the entire lens surface including the distal side without the nozzle physically obstructing the sensor's field of view
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances liquid coverage and shear force over the entire lens surface, improving efficiency and reducing the number of nozzles and liquid usage, while maintaining the sensor's field-of-view, thereby maintaining sensor functionality and reducing packaging complexity.
Implementation Method 1
The nozzle is configured to spray the liquid with laminar flow onto a proximal end of the lens such that the liquid flows across the lens from the proximal end to a distal end of the lens to remove debris
Implementation Method 2
creating a boundary layer that covers the entire lens surface
Data Source
AI summary
Disclosed herein are system, method, and computer program product embodiments for cleaning one or more sensors of a self-driving system (SDS). For example, the SDS is provided with a sensor with a lens that is formed with a convex outer surface. A nozzle is formed with an opening to provide a liquid in a stream at a fan angle relative to a spray axis. The nozzle is spaced apart from the sensor at a distance based on a radius of the lens and the fan angle and configured to spray the liquid with laminar flow onto a proximal end of the lens such that the liquid flows across the lens from the proximal end to a distal end of the lens to remove debris.