Eccentric Shutter Valve for Vehicle Tank Venting
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Solution Overview
Problem
Existing vehicle tank pressurization devices face difficulties in fully lifting the shutter from the valve seat and quickly reducing internal tank pressure when it slightly exceeds the threshold, leading to inefficient venting of air and fuel vapors.
Innovation Solution
A vehicle tank pressurization device with a unidirectional valve featuring a shutter with an eccentric center of gravity, allowing for easier movement and tilting, which enhances the outflow of air and fuel vapors by creating a larger section area for venting, and optionally incorporating a set point spring for additional closure stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a unidirectional valve with a weight and set point spring is used to maintain pressure threshold, then the valve remains closed during normal driving vibrations, but the shutter has difficulty fully lifting from the valve seat when pressure slightly exceeds the threshold
Solution Approach 1:
The shutter is designed with an asymmetric geometry where the center of gravity is offset from the vertical axis of symmetry. This creates a tilting moment when pressure acts on the shutter, enabling it to tilt and lift more effectively from the valve seat, thereby improving venting efficiency while maintaining closure stability through the set point spring and weight configuration
2Reliability
If the shutter weight is increased to maintain closure against vibrations, then the pressure threshold increases, but the shutter cannot quickly reduce pressure when slightly exceeding the threshold
Solution Approach 1:
The shutter is designed to tilt dynamically when pressure exceeds the threshold, transforming from a simple vertical lift motion to a rotational tilting motion. This dynamic behavior allows the shutter to overcome its weight and quickly open the venting passage, reducing pressure rapidly even when the threshold is only slightly exceeded, while the set point spring maintains stable closure during vibrations
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 device achieves quicker and more effective venting of air and fuel vapors, restoring tank pressure below the threshold value more efficiently than prior art solutions, with improved resistance to vibrations and jolts.
Implementation Method 1
when the pressure inside the tank reaches a specified threshold... the pressure in region 6 acts on area 17 and tends to raise shutter 14 to open opening 11
Implementation Method 2
a shutter (14) which moves within chamber (13) towards and away from valve seat (10) to open/close opening (11) in response to the pressure present in region (6)... the centre of gravity of shutter 14 is offset or eccentric with respect to axis 12
Implementation Method 3
It may also be provided with a set point spring with a relatively low preload, in order to keep the shutter closed against the valve seat despite the vehicle's jolts and vibrations in normal driving condition
Implementation Method 4
has a weight whose magnitude determines the operation of closure and, therefore, the aforesaid pressure threshold
Data Source
Figure 1
Figure 2a~3c
Figure 4a~4c
AI summary
A vehicle tank pressurisation device has a valve seat (10) establishing an opening (11) for fuel vapours and/or air; such opening (11) has a vertical axis (12) coincident with the direction of application of an opening force, that is directed upwards and is produced, in use, by the pressure in an internal upper region (6) of the tank (1); the device also has a movable shutter (14), placed on the valve seat (10), to open/close the valve seat (10), and having a weight set by design in such a way as to define the magnitude of a closing force directed downwards and with a centre of gravity positioned eccentrically with respect to the vertical axis (12) of the opening (11).