Liquid Spring Suspension With Valve-Controlled 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 between liquid volumes.
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 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 suspension system divides the liquid spring into separate volumes (first liquid volume in the vessel, second liquid volume in the cylinder) that can be independently controlled by a valve. This segmentation allows the system to adjust the effective spring volume to maintain consistent ride frequency across varying loads while avoiding the complexity of completely redesigning the suspension architecture.
Solution Approach 2:
The system dynamically adjusts the ride frequency characteristics by varying the volume of compressible liquid engaged in the spring function through valve control. As vehicle load changes, the valve reconfigures the fluid communication between liquid volumes to maintain optimal ride frequency, transforming a static suspension into an adaptive system without requiring complex active components.
2Adaptability or versatility
If the spring rate is increased to maintain ride frequency under heavy loads, then ride frequency consistency improves, but the suspension becomes overly stiff under light load conditions
Solution Approach 1:
The system changes the physical parameter of spring volume by reconfiguring fluid communication between different liquid volumes. Under light loads, a larger liquid volume provides a softer spring rate for comfort; under heavy loads, a smaller liquid volume provides a stiffer spring rate to maintain ride frequency, allowing the same physical system to adapt to different operating conditions.
Solution Approach 2:
The valve acts as an intermediary component that controls fluid communication between the first and second liquid volumes. This simple mediator enables the system to switch between different spring configurations without requiring complex active suspension components, maintaining ride comfort across varying load conditions through passive fluid routing.
3Adaptability or versatility
If a fixed volume liquid spring is used, then the suspension system is simple to operate, but it cannot maintain consistent ride frequency across varying vehicle loads
Solution Approach 1:
The system nests multiple liquid volumes within the suspension assembly, with the first liquid volume in the vessel and the second liquid volume in the cylinder. The valve selectively connects these nested volumes to create different effective spring volumes, allowing the system to adapt to various loads while maintaining a relatively compact and manufacturable configuration.
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 to compensate for 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.