Optical Cover Cleaning Nozzle Using Coanda Air-Liquid Jet
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Solution Overview
Problem
Existing cleaning devices for optical and optoelectronic devices in vehicles require frequent cleaning, leading to high consumption of cleaning fluid and potential optical distortions from water droplets, resulting in increased space, weight, and cost due to large reservoirs and frequent refill needs.
Innovation Solution
An electrically controlled cleaning device using compressed air and cleaning liquid, with a nozzle design that utilizes the Coandä effect to efficiently clean curved transparent elements, reducing fluid consumption by using air as a primary cleaning medium and allowing for adaptive operation based on environmental and operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cleaning liquid is used frequently to clean the transparent cover, then cleaning effectiveness is improved, but cleaning fluid consumption increases and reservoir size must be enlarged
Solution Approach 1:
Compressed air is introduced as an intermediary cleaning medium that can be mixed with cleaning liquid in the nozzle. This air-liquid mixture allows for more effective cleaning with reduced liquid consumption, as the air provides additional cleaning action through its expanding and drying effect while the liquid provides wet cleaning capability.
Solution Approach 2:
The cleaning system changes the parameters of the cleaning fluid by mixing compressed air with cleaning liquid in variable ratios. By adjusting the air-to-liquid ratio in the nozzle, the system can adapt the cleaning characteristics to different contamination levels and conditions, achieving effective cleaning with less liquid.
2Duration of action of moving object
If large reservoirs are provided to extend refill intervals, then cleaning fluid availability is improved, but space, weight and cost increase
Solution Approach 1:
Compressed air serves as an intermediary that extends the effective duration of cleaning fluid usage. By mixing air with cleaning liquid and utilizing the air's expanding and drying effects, the system achieves more cleaning cycles per unit volume of liquid, thereby extending refill intervals without increasing reservoir size.
Solution Approach 2:
The system replaces purely liquid-based cleaning with a pneumatic-pneumatic hybrid approach. Compressed air is used both as a cleaning medium and as a mechanism to extend the effectiveness of limited cleaning liquid, reducing the need for large liquid reservoirs while maintaining extended operation between refills.
3Quantity of substance
If compressed air is used to clean the transparent cover, then cleaning fluid consumption is reduced, but cleaning effectiveness may be insufficient for heavy contamination
Solution Approach 1:
The nozzle merges compressed air and cleaning liquid into a combined air-liquid cleaning jet. This combination allows the system to leverage both the mechanical impact and drying action of air and the wet cleaning capability of liquid, achieving effective cleaning of various contamination levels while consuming less liquid than traditional liquid-only systems.
Solution Approach 2:
The cleaning system is made dynamic by allowing variable mixing ratios of air and liquid in the nozzle. The control unit can adjust the proportion of air to liquid based on detected contamination levels, providing air-dominated mixing for light contamination and liquid-dominated mixing for heavy contamination, thereby optimizing cleaning effectiveness across different conditions.
4Reliability
If water droplets remain on the camera lens, then cleaning coverage is improved, but optical distortions occur in the camera image
Solution Approach 1:
The cleaning system employs periodic action through the expanding and collapsing phases of compressed air. The air jet is delivered in a manner that creates periodic expansion and collapse cycles, which effectively remove water droplets from the lens surface after wet cleaning, preventing optical distortions while maintaining thorough cleaning coverage.
Solution Approach 2:
The system utilizes phase transitions of water through the action of compressed air. The expanding air jet promotes rapid evaporation and phase change of residual water droplets on the lens surface, converting liquid water into vapor and eliminating the source of optical distortions while maintaining cleaning effectiveness.
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
The solution significantly reduces cleaning fluid usage, minimizes optical distortions, and extends refill intervals, ensuring reliable functionality in all weather conditions with reduced logistics and assembly complexity, while maintaining effective cleaning performance.
Implementation Method 1
the jet of cleaning agent is directed essentially at a radial outer edge of the transparent element for the purpose of utilizing the Coandä effect. In this case, it is particularly advantageous if the jet of cleaning agent is in the form of a flat jet, which essentially propagates in a plane orthogonal to the optical axis. As a result, the entire surface of the transparent element is effectively flushed and cleaned at comparatively low pressure
Data Source
Figure 1
AI summary
The invention relates to a cleaning device (1) for cleaning a transparent element (2) of an optical or optoelectronic device (3) with a fluid cleaning agent, comprising a housing (4) in which the device (3) is arranged, at least one fluid inlet (5) which is arranged in the housing (4), and at least one nozzle (7) which is supplied from the fluid inlet (5). The nozzle (7) is designed to deflect a cleaning agent jet (6) onto the transparent element (2), and the jet direction of the cleaning agent jet (6) is provided substantially transversely to an optical axis (9) of the transparent element (2). The aim of the invention is to improve the cleaning power with a reduced consumption of cleaning liquid. According to the invention, this is achieved in that the fluid inlet (5) is designed for a throughflow of a cleaning liquid out of a hydraulic channel (8) and compressed air out of a pneumatic channel (10), wherein the hydraulic channel (8) has a hydraulic nonreturn valve (11), and the pneumatic channel (10) has a pneumatic nonreturn valve (12), said nonreturn valves (11, 12) opening the channels (8, 10) in the direction of the nozzle (7) and blocking the channels in the opposite direction.