Individual Wheel Drive Coupling for Efficient Rear Torque Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing individual wheel drive systems in two-axle motor vehicles with electrified axles face challenges in achieving efficient torque distribution and energy management, leading to suboptimal driving dynamics due to excessive torque deviations, particularly in multiple-motor concepts where one axle is decoupled for efficiency, preventing desired rear wheel drive configurations.
Innovation Solution
A device with an electronic control unit and adjustable coupling unit between electric drive motors, allowing for two actuating modes: one where one motor drives both wheels, and another where both motors drive separate wheels, utilizing sliding sleeves for efficient decoupling and coupling, enabling better operational points for energy efficiency while maintaining rear wheel drive capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If both electric drive motors drive separate wheels (mode 2), then torque distribution flexibility is improved, but energy consumption increases and functional reliability decreases due to higher demand on torque accuracy
Solution Approach 1:
The system dynamically switches between actuating mode 1 (one motor driving both wheels) and actuating mode 2 (both motors driving separate wheels) based on operating conditions. This allows the system to adapt torque distribution flexibility when needed while conserving energy during normal operation, resolving the contradiction between versatility and energy consumption.
Solution Approach 2:
The drive system is segmented into two independent electric drive motors that can operate independently or in combination. The coupling unit allows selective engagement of each motor to the drive shaft, enabling the system to use only one motor when sufficient for the driving task, thereby reducing energy consumption while maintaining the capability for flexible torque distribution when both motors are engaged.
2Adaptability or versatility
If both electric drive motors drive separate wheels (mode 2), then torque distribution flexibility is improved, but driving dynamics deteriorate due to excessive torque deviation from target values
Solution Approach 1:
The control system dynamically selects between actuating mode 1 and mode 2 based on real-time operating conditions and torque requirements. By switching to mode 1 when torque accuracy cannot be maintained, the system ensures acceptable driving dynamics while still providing access to flexible torque distribution when conditions permit, thus resolving the contradiction between adaptability and reliability.
Solution Approach 2:
The system monitors torque output and operating conditions to determine when to switch between actuating modes. This feedback mechanism ensures that mode 2 (both motors driving separately) is only used when torque distribution can be accurately controlled, preventing excessive torque deviation that would degrade driving dynamics, while still allowing flexible torque distribution when conditions are favorable.
3Use of energy by moving object
If the rear axle is decoupled for efficiency (prior art approach), then energy efficiency improves, but rear wheel drive capability is lost requiring front axle only operation
Solution Approach 1:
Instead of decoupling the entire rear axle, the system segments the drive function at the motor level, allowing one electric drive motor to be decoupled while the other remains engaged. This enables the rear wheels to continue receiving drive torque through the engaged motor and differential, maintaining rear wheel drive capability while improving energy efficiency by operating with a single motor when conditions permit.
Solution Approach 2:
The system dynamically adjusts which electric drive motor is active based on driving conditions. The coupling unit enables selective engagement of the first or second electric drive motor to the drive shaft, allowing the system to switch between efficiency-oriented operation (one motor) and capability-oriented operation (both motors available), thus resolving the contradiction between energy efficiency and rear wheel drive capability.
Data Source
AI summary
An apparatus for controlling an individual wheel drive in a two-axle motor vehicle having at least one electrified vehicle axle on which an electric drive motor is associated with each wheel is provided. The apparatus includes an electronic controller and a coupling which can be controlled by the electronic controller between the electric drive motors, wherein the electronic controller and the coupling are configured in such a way that (i) given at least one first specified condition in a first actuating mode, only one defined electric drive motor drives both wheels, with the other electric drive motor being stopped, and (ii) given at least one second specified condition in a second actuating mode, both electric drive motors drive one wheel each, separately from one another.