Liquid Spring Suspension With Variable Rate for Stable Ride Frequency
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Solution Overview
Problem
Conventional suspension systems exhibit wide variance in ride frequency over varying vehicle loads, leading to harsh or soft ride conditions depending on load conditions.
Innovation Solution
A suspension system incorporating a hydraulic accumulator with compressible liquid and gas coupled as a series spring, where the spring rate increases proportionally with vehicle weight, maintaining a constant ride frequency through varying loads using a valve to control fluid communication and isolation between liquid volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional suspension systems (leaf spring, hydraulic, or air suspensions) are used, then the suspension system is simple in structure and easy to manufacture, but the ride frequency varies widely over a wide range of vehicle loads
Solution Approach 1:
The patent applies dynamics by making the spring rate variable rather than fixed. The liquid spring system allows the effective spring rate to change dynamically with vehicle load, automatically adjusting to maintain consistent ride frequency across different load conditions. This resolves the contradiction by enabling the suspension to adapt its characteristics based on operating conditions without requiring complex active control systems.
Solution Approach 2:
The patent changes the physical parameters of the suspension system by using compressible liquid instead of traditional springs. The bulk modulus of the liquid and the variable volume chamber configuration allow the spring rate parameter to change with load, maintaining optimal ride frequency from curb weight to gross vehicle weight rating without requiring multiple spring sets or complex adjustment mechanisms.
2Ease of operation
If conventional suspension systems are used, then the system is easy to operate, but the ride quality is harsh under some load conditions and soft under other load conditions
Solution Approach 1:
The liquid spring suspension system is self-regulating and requires no operator intervention. The system automatically adjusts its spring rate based on the vehicle load through the inherent properties of the compressible liquid and variable volume chamber, eliminating the need for manual adjustment while maintaining optimal ride quality across all load conditions.
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 system maintains a consistent ride frequency within approximately 8% of a desired frequency from 50% to 80% of the gross axle weight rating, optimizing rider comfort by adjusting spring rate in response to load changes.
Implementation Method 1
A first spring function exhibited by the compressible liquid in the cylinder, the first liquid volume, and the second liquid volume may be in series with a second spring function exhibited by the spring element in the hydraulic accumulator
Implementation Method 2
a spring element in the volume of the hydraulic accumulator
Implementation Method 3
The valve may be configured to move between an open configuration in which the compressible liquid in the cylinder is in fluid communication with the compressible liquid in the second liquid volume in the vessel, and a closed configuration in which the compressible liquid in the cylinder is isolated from the compressible liquid in the second liquid volume
Data Source
AI summary
A suspension system configured to exhibit low variance in vehicle ride frequency over a large range of vehicle loads. The suspension system includes a strut having a cylinder and a piston configured to reciprocate in the cylinder. The suspension system also includes a vessel coupled to the strut, and a valve in an interior chamber of the vessel. The valve divides the interior chamber into a first liquid volume and a second liquid volume. The suspension system also includes a hydraulic accumulator having a volume and a liquid volume. The suspension system further includes a compressible liquid in the cylinder, the first liquid volume in the vessel, and the second liquid volume in the vessel, and a spring element in the volume of the hydraulic accumulator.