Electronic Limited Slip Differential Torque Control
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Solution Overview
Problem
Existing limited slip differentials do not effectively adjust coupling torque based on vehicle mass, leading to inadequate maneuverability and stability during turns, especially for heavily-loaded vehicles.
Innovation Solution
An electronic controller determines the vehicle's mass and adjusts the limited-slip-differential coupling torque dynamically, applying a modified torque that takes into account the difference between estimated and curb mass, using lookup tables for velocity and braking characteristics to optimize yaw moment and wheel rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed default coupling torque is applied in limited slip differentials, then the device complexity is reduced and ease of operation is improved, but the adaptability to different vehicle mass conditions deteriorates and maneuverability becomes inadequate for heavily-loaded vehicles
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed default coupling torque to a dynamic adaptive coupling torque that changes based on real-time vehicle mass estimation. The electronic controller continuously estimates vehicle mass using sensor data (accelerometer, gyroscope, wheel speed sensors) and adjusts the coupling torque accordingly, allowing the limited slip differential to adapt to varying load conditions while maintaining ease of operation through automated control.
Solution Approach 2:
The patent implements parameter changes by modifying the coupling torque parameter based on estimated vehicle mass. The system calculates the difference between estimated mass and curb mass, then adjusts the coupling torque using lookup tables that correlate mass differences with optimal torque values. This dynamic parameter adjustment enables the system to maintain optimal performance across different loading conditions.
2Stability of the object's composition
If the coupling torque is increased for heavily-loaded vehicles to improve stability and maneuverability, then the maneuverability and stability during turns are improved, but the device complexity increases due to mass estimation and dynamic torque adjustment systems
Solution Approach 1:
The patent applies universality by making the electronic controller perform multiple functions: it manages engine control, transmission control, and now also mass estimation and limited slip differential control. By integrating these functions into a single controller, the system achieves improved stability and adaptability without proportionally increasing overall device complexity, as the controller leverages existing sensor infrastructure and processing capabilities.
Solution Approach 2:
The system implements self-service through automated vehicle mass estimation using onboard sensors (accelerometers, gyroscopes, wheel speed sensors) without requiring external input from the driver. The electronic controller autonomously estimates mass, determines load conditions, and adjusts coupling torque accordingly, eliminating the need for manual intervention or additional complex input mechanisms while improving stability.
3Adaptability or versatility
If dynamic mass estimation and adaptive torque control are implemented, then the adaptability to different vehicle loads is improved and maneuverability is enhanced, but the use of energy increases due to continuous sensing and control adjustments
Solution Approach 1:
The patent applies partial action by selectively activating full dynamic torque adjustment only when needed - specifically when the estimated vehicle mass exceeds the curb mass by a threshold amount indicating a heavily-loaded condition. For normal loading conditions, the system can operate with default or reduced control intervention, thereby reducing energy consumption while maintaining adaptability when it matters most.
Data Source
AI summary
A system and method for electronically controlling a limited slip differential is disclosed. The method includes determining, by an electronic controller of a vehicle, a request for a limited-slip-differential coupling torque to be applied. The request is based upon an estimation of the vehicle's mass. The method also includes transmitting the request to an electronic limited slip differential of the vehicle. The electronic limited slip differential is configured to apply the requested limited-slip-differential coupling torque.