Washer Fluid Valve Assembly for Cold Weather Evacuation
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Solution Overview
Problem
Existing windshield washer fluid distribution circuits fail to prevent freezing of washer fluid in nozzles and external pipe sections during cold weather, leading to operational issues and increased response time when the fluid is not completely purged from the system.
Innovation Solution
A valve assembly with a piston and cylinder system that directs washer fluid to nozzles when the pump is activated and suctions it back to the pump when stopped, using a helical compression spring and radial bores to ensure complete evacuation of fluid from external pipe sections, preventing freezing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the windshield washer fluid is completely bled from the distribution circuit by returning it to the reservoir to prevent freezing, then the nozzles and external pipe sections are protected from freezing, but the response time of the window washing function is lengthened
Solution Approach 1:
The distribution circuit is segmented into an internal section (from pump to valve assembly) and an external section (from valve assembly to nozzles). The valve assembly acts as a segmentation point that can isolate the external section from the internal section, allowing the internal section to retain fluid while the external section can be evacuated.
Solution Approach 2:
The valve assembly extracts the windshield washer fluid from the external pipe section and returns it to the pump, removing the harmful fluid from the external section that would otherwise freeze, while maintaining fluid in the internal section for quick response.
Solution Approach 3:
The valve assembly dynamically changes the flow direction based on system state. When the pump stops, the valve automatically redirects flow to evacuate the external section. When the pump activates, the valve switches to supply mode, enabling rapid response without requiring complete system purging.
2Reliability
If a valve is used to direct washer fluid towards the nozzle when the pump is activated and evacuate fluid from the external pipe section when the pump is stopped, then freezing is prevented, but the device complexity increases
Solution Approach 1:
The valve assembly operates automatically based on pump operation state without requiring external control signals. The system self-regulates by detecting pump activation status and automatically switching between supply and evacuation modes, eliminating the need for complex control circuits or additional actuators.
Solution Approach 2:
The valve assembly combines multiple functions into a single component: it acts as both a flow director during pumping and an evacuation valve during idle periods. This merging of functions reduces the need for separate control mechanisms and simplifies the overall system architecture.
3Device complexity
If gravity is used to evacuate windshield washer fluid from the external pipe section, then the system remains simple, but some fluid remains in horizontal pipe sections and low points, causing freezing
Solution Approach 1:
The pump creates a negative pressure (suction) that actively draws fluid from the external pipe section through the valve assembly and back to the reservoir. This hydraulic action overcomes gravity's limitations in horizontal sections, ensuring complete fluid removal from all areas including low points and horizontal runs.
Solution Approach 2:
Instead of relying on gravity to drain fluid downward (which fails in horizontal sections), the system inverts the approach by using suction to pull fluid upward and outward from all sections of the external piping, effectively reversing the traditional drainage approach.
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
Ensures the windshield washer fluid distribution circuit remains functional in cold weather by preventing fluid from freezing in external sections, maintaining quick response times without the need for full circuit purging.
Implementation Method 1
the piston being able to be moved by the windscreen washer fluid in the first chamber against the return force of an elastically deformable member when the pump is activated
Implementation Method 2
the return force of an elastically deformable member
Implementation Method 3
a valve housed in the piston and capable of occupying an open position of a communication passage between the two chambers when the piston is in the first chamber to direct the windscreen washer fluid towards the nozzle and a position of blocking of this passage when the piston is moved by the elastically deformable member
Implementation Method 4
to suck in the first chamber the windshield washer fluid present in the pipe section and return the washer fluid to the pump
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present invention relates to a washer fluid dispensing circuit for a motor vehicle and to a method for protecting such a circuit. According to the invention, the dispensing circuit comprises an assembly involving a valve (6) comprising a cylinder (11), a piston (12) able to move in the cylinder (11) which can be moved by the washer fluid in a chamber (13) against the return force of an elastically deformable member (20) when the pump (3) is activated, a valve (21) housed in the piston (12) and able notably to occupy a position of shutting off a passage when the piston (12) is moved by the member (2) in another chamber (14) and the pump (3) is stopped in order to draw into the chamber (13) the washer fluid present in the portion of pipe (7). The invention finds an application in the automotive field.