Regenerative Shock Absorber with Back-EMF Damping
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Solution Overview
Problem
Conventional shock absorbers in vehicle suspension systems waste energy as heat, and existing regenerative systems either lack damping functionality or require separate shock absorbers, making them inefficient and complex.
Innovation Solution
A regenerative shock absorber that integrates a permanent magnet generator/DC electric motor with a capacitive reservoir and hydraulic circuit, providing both energy recovery and damping functionality, eliminating the need for a separate shock absorber by using back-EMF to resist rotational motion and adjust damping forces proportionally to fluid velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional shock absorber is used to provide damping, then damping function is achieved, but energy is wasted as heat
Solution Approach 1:
The patent replaces the conventional mechanical damping system with an electromechanical system. A permanent magnet generator converts the reciprocating motion of the shock absorber into rotational motion, which then drives a DC motor that provides electromagnetic damping torque. This substitution allows energy recovery through generation while maintaining damping control through electromagnetic forces.
Solution Approach 2:
The patent changes the operational parameters of the system by introducing electrical energy conversion. The permanent magnet generator converts mechanical energy to electrical energy, and the DC motor converts electrical energy back to mechanical damping torque. This parameter transformation enables both energy recovery and controlled damping, eliminating the heat waste inherent in conventional purely mechanical shock absorbers.
2Loss of energy
If a regenerative system is used to recover energy, then energy recovery is achieved, but damping functionality is lost or requires separate shock absorbers
Solution Approach 1:
The patent merges the regenerative energy recovery function and the damping function into a single integrated system. The permanent magnet generator and DC motor are combined within the shock absorber assembly, allowing both energy recovery and damping to be achieved through the same mechanical components. This eliminates the need for separate shock absorbers and reduces overall system complexity.
Solution Approach 2:
The shock absorber system performs multiple functions simultaneously: it provides damping control through the DC motor's electromagnetic torque and recovers energy through the permanent magnet generator. The hydraulic circuit serves both to control the reciprocating motion for damping and to drive the generator for energy recovery. This multi-functionality eliminates the need for additional separate components.
3Use of energy by moving object
If the hydraulic circuit is designed for energy recovery, then energy efficiency is improved, but damping control may be compromised
Solution Approach 1:
The system employs feedback control where the DC motor's electromagnetic torque provides active damping based on the reciprocating motion of the shock absorber. The permanent magnet generator converts this motion into electrical energy, and the motor uses this energy to provide counteracting damping torque. This feedback mechanism ensures that damping control is maintained while maximizing energy recovery, as the system actively responds to motion to both harvest energy and provide stabilization.
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 solution effectively recovers energy from vehicle suspension motion, enhances fuel efficiency by using harvested electricity, and provides adjustable damping, improving the overall energy utilization and reducing the need for additional shock absorbers.
Implementation Method 1
U.S. Patent No. 5,570,286 that utilizes a magnet moving in relation to conductive coils
Implementation Method 2
the back-emf resists rotational motion of the armature relative to the stator
Implementation Method 3
hydraulic system for recovering energy from the relative motion between a vehicle body and its wheels
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Regenerative shock absorber. A piston (12) is disposed for reciprocating motion within a cylinder as a vehicle's suspension system deflects. Hydraulic fluid passes through an hydraulic motor (20) to turn its shaft. The hydraulic motor shaft is connected to an electric generator (50) to generate electricity. Flow characteristics of hydraulic circuits are selected to provide suspension system damping for appropriate wheel control.