Liquid Spring Suspension With Variable Volume for Stable Ride Frequency
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Solution Overview
Problem
Conventional vehicle suspension systems exhibit significant variance in ride frequency across different vehicle loads, resulting in harsh or soft ride conditions depending on load conditions, failing to maintain an ideal ride frequency over a wide range of weights.
Innovation Solution
A suspension system incorporating a hydraulic accumulator with compressible liquid and gas, coupled as a series spring with a compressible liquid spring system, which increases spring rate proportionally with vehicle weight, maintaining a constant ride frequency by varying the effective volume of compressible liquid through a valve configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional suspension systems (leaf spring, hydraulic, or air suspensions) are used, then the suspension system provides basic ride support, but the ride frequency varies widely over a wide range of vehicle loads
Solution Approach 1:
The suspension system dynamically adjusts its spring rate by varying the volume of compressible liquid in the hydraulic accumulator based on vehicle load conditions. At lighter loads, a larger liquid volume provides a softer spring rate, while at heavier loads, a smaller liquid volume provides a stiffer spring rate, maintaining consistent ride frequency across the load range.
Solution Approach 2:
The system changes the physical parameter of liquid volume in the hydraulic accumulator to adjust suspension characteristics. By controlling the volume of compressible liquid, the system modifies the effective spring rate to compensate for varying vehicle loads and maintain optimal ride frequency.
2Manufacturing precision
If the suspension system is designed for ideal ride frequency at a specific load (e.g., curb weight or 100% GAWR), then optimal performance is achieved at that load, but harsh or soft ride conditions occur under other load conditions
Solution Approach 1:
The suspension system transitions from a static spring rate design to a dynamic one where the spring rate automatically adjusts with vehicle load. The hydraulic accumulator's liquid volume changes in response to load variations, enabling the system to adapt to different operating conditions while maintaining precise ride frequency control.
Solution Approach 2:
The hydraulic accumulator serves multiple functions: it acts as a spring element, a damper, and a load-sensing device simultaneously. This multi-functionality allows the single system to handle diverse load conditions from light to heavy payloads while maintaining consistent suspension performance.
3Device complexity
If a fixed volume of compressible liquid is used in the hydraulic accumulator, then the system structure is simple, but the spring rate cannot adjust to varying vehicle loads
Solution Approach 1:
The system incorporates a variable volume hydraulic accumulator that can dynamically adjust the amount of compressible liquid based on vehicle load. This dynamic volume adjustment capability enables spring rate adaptability while adding only minimal structural complexity to the overall suspension system.
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 range from 50% to 80% of the gross axle weight rating, optimizing rider comfort by ensuring a stable ride experience across varying loads.
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
The suspension system also includes a hydraulic accumulator having a volume and a liquid volume
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.