Clutched Flywheel Transmission for Seamless Torque Transfer
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Solution Overview
Problem
Current mechanical Energy Storage and Recovery System (ESRS) devices are bulky, heavy, and costly, limiting their application to less powerful and lighter vehicles, with inefficiencies in torque transfer at lower power levels and potential for torque discontinuity during gear changes.
Innovation Solution
A compact ESRS device utilizing multiple wet multiplate clutches with independent torque transfer efficiency, allowing seamless gear changes without torque interruption, and a lubrication system to manage heat, enabling efficient energy storage and recovery with reduced weight and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a CVT is used to transfer torque between the flywheel and the vehicle, then torque transfer efficiency is improved at high power levels, but the device becomes larger, heavier and more expensive
Solution Approach 1:
The CVT is replaced by a segmented gear transmission system with multiple discrete gear ratios (typically 3-5 ratios). Each gear ratio is engaged through separate clutches, dividing the continuous transmission function into discrete segments that achieve similar efficiency benefits without the complexity and weight of a full CVT mechanism.
Solution Approach 2:
The patent uses simpler, more cost-effective gear and clutch components instead of expensive CVT mechanisms. While individual clutch plates experience wear during slip operations, the overall system is more economical and maintainable, replacing complex continuous variable transmission components with durable discrete gear elements.
2Loss of energy
If a CVT is used for torque transfer, then high efficiency is achieved, but the device complexity increases
Solution Approach 1:
The complex CVT mechanism is segmented into simpler discrete gear ratios controlled by individual clutches. This segmentation reduces mechanical complexity while maintaining efficiency through multiple gear stages, each engaged independently based on operating conditions.
Solution Approach 2:
The patent extracts the essential function of continuous variable transmission (smooth torque transfer across multiple ratios) and implements it through a simplified combination of discrete gears and controllable clutches, removing the complex belt-pulley or planetary mechanisms inherent in traditional CVTs.
3Adaptability or versatility
If clutches slip momentarily during gear connection, then gear changes are achieved, but torque discontinuity occurs
Solution Approach 1:
Multiple clutches are combined in parallel, each controlling a different gear ratio path. During gear transitions, clutches are engaged and disengaged in a coordinated sequence that maintains continuous torque flow from the flywheel to the output, merging multiple torque paths to eliminate discontinuity.
Solution Approach 2:
The clutch control system performs preliminary engagement of the outgoing clutch before fully disengaging the incoming clutch. This overlapping engagement ensures that torque transfer is maintained throughout the transition, preventing any interruption in the torque chain.
4Weight of stationary object
If the ESRS device is made smaller and lighter, then it can be fitted to less powerful vehicles, but thermal management becomes more challenging
Solution Approach 1:
A hydraulic cooling system is integrated into the compact clutch assembly, using fluid circulation to extract heat from the clutch plates. This hydraulic cooling mechanism allows effective thermal management within a reduced device footprint, preventing overheating despite the smaller size and closer proximity of components.
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 solution achieves high round trip efficiency (around 65%) with weight and cost savings, eliminating torque discontinuity and thermal management challenges, while allowing retrofitting on existing vehicles and optimizing vehicle performance.
Implementation Method 1
multiple wet multiplate clutches with independent torque transfer efficiency
Implementation Method 2
a lubrication system to manage heat
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An energy storage and recovery system device (2) for a vehicle, comprising a flywheel (4), a first and a second set of gears (4; 6), and multiple wet mutliplate clutches (10, 12, 14), wherein one of each gear set (4; 6) is arranged coaxially along a clutch shaft (34, 36, 38) with one of the clutches (10, 12, 14), and wherein the device (2) is coupled to the vehicle transmission, such that actuation of a clutch redirects the torque path via the gears, thereby enabling multiple ratios and therefore multiple speeds.