Distributed Piston Elastomeric Accumulator Eliminates Gas Diffusion
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Solution Overview
Problem
Conventional hydraulic accumulators, such as gas extendable membrane and piston accumulators with gas pre-charge, face inefficiencies due to heat losses and gas diffusion issues, making them unsuitable for hydraulic regenerative braking applications.
Innovation Solution
A distributed piston elastomeric accumulator design that eliminates the need for pressurized gas by using an elastomeric material to store strain energy, optimizing energy storage capacity and avoiding radial strain gradients, allowing hydraulic fluid pressure to exceed material stress, and enabling precise energy transfer rate calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If gas is used for energy storage in conventional accumulators, then energy can be stored and released, but heat losses occur reducing efficiency
Solution Approach 1:
The patent removes the gas component entirely from the accumulator system. Instead of using gas compression/expansion for energy storage, the invention employs direct hydraulic fluid compression using a spring mechanism, thereby eliminating the source of heat losses associated with gas compression and expansion cycles.
Solution Approach 2:
The patent replaces the gas-based thermodynamic system with a purely mechanical spring-based system. The spring directly compresses the hydraulic fluid without involving gas, substituting a mechanical energy storage mechanism that avoids thermal losses inherent in gas compression.
2Use of energy by moving object
If gas is used in piston accumulators, then energy storage is enabled, but gas diffusion through the bladder or piston into the hydraulic fluid occurs
Solution Approach 1:
The patent completely removes gas from the system by eliminating the bladder or piston separator that would otherwise be required to contain gas. The design uses direct hydraulic fluid compression with a spring, making gas diffusion impossible since no gas is present.
Solution Approach 2:
The patent transitions from a pneumatic-hydraulic hybrid system (gas + hydraulic fluid) to a purely hydraulic system with mechanical energy storage. This eliminates the interface between gas and hydraulic fluid that causes diffusion problems.
3Loss of energy
If elastomeric foam is added to the gas enclosure, then thermal loss is reduced, but device complexity increases
Solution Approach 1:
The patent eliminates the need for elastomeric foam by removing the gas enclosure entirely. Without gas compression, there is no thermal loss to mitigate, and consequently no need for thermal management components like foam insulation.
Solution Approach 2:
The patent replaces the gas-foam thermal management system with a simpler mechanical spring system that inherently avoids thermal losses through its isochoric compression process, eliminating the need for additional thermal management components.
4Loss of substance
If gas pressure is maintained below fluid pressure, then gas diffusion is reduced, but energy storage capacity is limited
Solution Approach 1:
The patent removes gas from the system entirely, making the pressure relationship irrelevant. Energy storage capacity is achieved through spring compression of hydraulic fluid without any gas involved, eliminating the trade-off between diffusion reduction and capacity.
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 design enhances energy storage efficiency, reduces maintenance costs, and improves the performance of hydraulic regenerative braking systems by maximizing strain energy density and allowing for accurate energy transfer rate measurements.
Implementation Method 1
an elastomeric material to store strain energy
Implementation Method 2
the piston slidably engages the housing
Data Source
AI summary
The present invention is a distributed piston elastomeric accumulator which stores energy when its elastomeric member stretches from its original length in response to the flow of a pressurized fluid. The stored energy is returned when the fluid flow is reversed and the accumulator discharges the fluid as its elastomeric member returns to its original length and moves the piston to its initial position. At least one part of the novelty of the invention is that the accumulator is not subject to radial strain gradients and the accumulator allows for precise pressure and linear position measurements. Accordingly, the invention allows for optimization of the energy strain storage capacity of a given elastomer.