Dual Accumulator Suspension Layout to Bypass Pump Inertia
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Solution Overview
Problem
Active vehicle suspension systems face challenges in maintaining desired stiffness across their operating range and responding to various input frequencies, leading to a rough ride experience due to pump inertia and fluid pressure differentials.
Innovation Solution
The implementation of a suspension system component with two separate accumulators, a compression accumulator, and an extension accumulator, which allows fluid to flow between the chambers without passing through the hydraulic pump, effectively bypassing pump inertia and maintaining desired stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a hydraulic pump is used to generate pressure differentials in the suspension system, then active suspension control is achieved, but pump inertia causes excessive stiffness at certain frequencies leading to rough ride
Solution Approach 1:
A bypass valve is introduced as an intermediary component that allows fluid to flow between the compression and extension chambers independently of the hydraulic pump. This mediator bypasses the pump inertia problem while maintaining active suspension control capability, resolving the contradiction between automation and harmful stiffness.
Solution Approach 2:
The fluid flow path is segmented into two independent pathways: one through the hydraulic pump for active control and another through the bypass valve for inertia-free flow. This segmentation allows the system to achieve both active suspension control and avoidance of pump inertia effects simultaneously.
2Force
If the suspension system uses high pressure differentials for stiffness control, then suspension support is improved, but the system becomes overly stiff at high frequencies
Solution Approach 1:
The bypass valve provides a dynamic alternative flow path that activates when pump inertia causes excessive stiffness. The system dynamically switches between pump-controlled flow and bypass flow based on operating conditions, maintaining optimal stiffness across different frequencies while preserving suspension support capability.
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
This configuration ensures that the suspension system maintains a desired stiffness across its operating range and responds effectively to a wide range of input frequencies, improving the ride experience by reducing the transfer of road inputs to the vehicle body.
Implementation Method 1
allows fluid to flow between the chambers without passing through the hydraulic pump
Implementation Method 2
The implementation of a suspension system component with two separate accumulators, a compression accumulator, and an extension accumulator
Implementation Method 3
when the hydraulic pump generates a first commanded pressure differential
Data Source
AI summary
Presented herein, inter alia, are suspension system components having tuned accumulator sizing and/or stiffness. Such suspension system components are envisioned for use in a distributed active suspension system of a vehicle. In particular, through appropriate sizing of accumulators of a suspension system component of a vehicle, ride quality of the vehicle may be improved and so called “rough ride” issues may be precluded. Alternatively or additionally, various valves or alternative compliant mechanisms may be included in the suspension system component, so that desirable performance may be obtained for a range of operating conditions.