EV Wheel Release Clutch for Towing Without Back-EMF Damage
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Solution Overview
Problem
Existing electric vehicles lack a robust wheel release mechanism and towing logic that can handle high torque environments, protect high voltage electrical components during towing, and prevent damage from reverse electromotive force (EMF) or uncontrolled regenerative charging, which can occur when wheels are rotated while disconnected or connected to the power source.
Innovation Solution
A wheel release mechanism using electromagnetic gear-toothed clutches mounted near the electric drive motor output shafts, combined with existing brake discs and hydraulic braking technology, allows wheels to be easily engaged or disengaged, and includes safety features to prevent damage by managing EMF and uncontrolled charging during towing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the wheels are disconnected from the power source during towing, then the vehicle can be towed with wheels on the ground, but reverse EMF and uncontrolled regenerative charging can damage high voltage electrical components
Solution Approach 1:
An electromagnetic clutch is introduced as an intermediary device between the wheel and the electric motor. The clutch can be disengaged during towing to disconnect the wheel from the motor, preventing reverse EMF from reaching the high voltage electrical components while still allowing the wheel to rotate freely on the ground
Solution Approach 2:
The wheel is extracted or separated from the powertrain system during towing operations through the electromagnetic clutch mechanism. This allows the wheel to be independently rotated without being connected to the electric motor, eliminating the harmful reverse EMF effect on electrical components
2Reliability
If the wheels remain connected to the power source during towing, then electrical components are protected, but uncontrolled regenerative charging can overcharge the battery and overheat the electric motor
Solution Approach 1:
The electromagnetic clutch acts as a mediator that can be disengaged to prevent the wheel from directly driving the electric motor during towing. This eliminates uncontrolled regenerative charging that would otherwise occur when the wheel rotates the motor, preventing battery overcharging and motor overheating
Solution Approach 2:
The wheel is extracted from the powertrain connection during towing through the electromagnetic clutch, removing the source of uncontrolled regenerative energy that would cause motor overheating and battery overcharging
3Adaptability or versatility
If a wheel release mechanism is added to enable towing, then towing options are provided, but the mechanism must withstand high wheel torque during normal operation
Solution Approach 1:
The traditional mechanical wheel release mechanism is replaced with an electromagnetic clutch that uses electromagnetic fields to engage and disengage the wheel from the motor. This electromagnetic system can withstand high wheel torque during normal operation while providing reliable disengagement for towing operations without requiring complex mechanical strength
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 effectively prevents damage to high voltage systems by managing EMF and uncontrolled charging, ensuring safe towing conditions and quick emergency braking, using commercially available components and reducing production costs.
Implementation Method 1
wheel release mechanism using electromagnetic gear-toothed clutches mounted near the electric drive motor output shafts
Implementation Method 2
existing brake discs and hydraulic braking technology
Implementation Method 3
hydraulic braking technology
Implementation Method 4
induce a large reverse electromotive force (EMF), and cause temperature excursions
Implementation Method 5
the drive system may enter an uncontrolled regenerative charging state, that overcharges the battery or flow cell
Data Source
AI summary
Presented herein is an electric vehicle's electromagnetic gear-toothed clutch wheel release mechanism and associated control logic for providing comprehensive towing capabilities, the method and components needed for operating and towing electric vehicles, and features for protecting the vehicle's high or low voltage drivetrain and electrical components during flat or inclined towing. Controlling the operation of electric drive vehicles includes all modes of normal driving, braking, parking, and towing. This design moves braking components toward the drive motors, installs electromagnetic clutches, engages and disengages the clutches to provide for driving, braking, parking, and towing, provides a failsafe if the vehicle separates from the towing vehicle, protects high and low voltage components from damage that would occur if subjected to counter electromotive forces from a continuously rotating drive motor, removes uncontrolled regenerative charging, and prevents unfettered heat generation and unwanted voltages transmitted through the electrical system and battery cells.