Electrically Controlled Center Coupler Torque Modulation for Yaw Stability
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Solution Overview
Problem
Brake-based vehicle stability-control systems often deteriorate longitudinal performance, especially during vehicle acceleration, and fail to effectively enhance vehicle stability and traction control.
Innovation Solution
An active stability control system using an electronically controlled center coupling apparatus that modulates torque transfer between the front and rear axles based on the difference between actual and desired yaw rates, enhancing lateral dynamics and traction control while preserving longitudinal motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If brake-based stability-control systems are used to correct vehicle yaw dynamics, then vehicle stability is improved, but longitudinal performance deteriorates during vehicle acceleration
Solution Approach 1:
The invention extracts the stability control function from the brake system and transfers it to the center coupling apparatus. By controlling the center coupler to transfer torque between front and rear axles based on yaw rate feedback, the system achieves stability control without using brake forces, thereby preserving longitudinal acceleration performance while correcting vehicle yaw dynamics
Solution Approach 2:
The invention replaces the brake-based mechanical stability control system with a torque transfer mechanism through the center coupling apparatus. Instead of using friction brakes to counteract unwanted yaw motion, the system uses the drivetrain itself to generate corrective moments by differentially torquing the axles, substituting a more efficient mechanical approach that doesn't dissipate energy
2Stability of the object's composition
If brake-based stability-control systems are used, then vehicle yaw dynamics are corrected, but energy is dissipated and traction control is insufficient
Solution Approach 1:
The invention converts the potential harm of energy dissipation into a benefit by using the drivetrain's torque transfer capability. Instead of wasting energy through brake friction, the system recycles engine torque through the center coupling apparatus to achieve yaw control, turning the powertrain into a productive control element rather than an energy sink
Solution Approach 2:
The system dynamically adjusts torque distribution between axles based on real-time yaw rate feedback. The center coupling apparatus modulates torque transfer continuously to match actual vehicle dynamics, creating a dynamic stability control system that adapts to changing driving conditions rather than relying on static brake application
3Productivity
If center coupling apparatus is used to transfer torque between axles, then traction control is enhanced, but vehicle yaw stability may be compromised without proper control
Solution Approach 1:
The system implements closed-loop feedback control by continuously monitoring actual yaw rate and comparing it to desired yaw rate. The center coupling apparatus torque transfer is dynamically adjusted based on the yaw rate error signal, ensuring that traction enhancement through torque distribution does not compromise vehicle yaw stability
Data Source
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AI summary
A control system for a vehicle having first and second axles (26, 30) is provided that includes a coupling apparatus (32) adapted to distribute torque between the first and second axles (26, 30) and a traction controller (64) for controlling operation of the differential apparatus from vehicle launch up to a predetermined vehicle speed. The traction controller is configured to engage the coupling apparatus (32) in a first operating state according to at least one vehicle operating parameter indicative of a low traction operating condition, in particular based on speed difference between the first and second axle (26, 30) and to further control engagement of the coupling apparatus in a second vehicle operating state during the low traction operating condition according to a difference between an actual vehicle yaw rate and a predetermined target vehicle yaw rate.