Superposition Torque Vectoring for Yaw Control
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Solution Overview
Problem
Existing methods for inducing a vehicle yaw moment, such as applying a clutch in an axle or differential clutch, are limited by the need for engine torque, making it difficult to generate a desired yaw moment when engine torque is low or zero, particularly when the accelerator pedal is released.
Innovation Solution
The implementation of super positioning torque vectoring, which involves increasing traction torque and applying equal and opposite vectoring torques to the wheels, even when driver demand torque is low or zero, using a combination of propulsion source torque adjustments, axle or differential clutch torque capacities, and friction brake torques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a clutch of an axle or differential clutch is applied to generate vehicle yaw moment, then torque difference between left and right wheels is generated, but vehicle yaw moment cannot be generated when engine torque is low or zero
Solution Approach 1:
The patent combines multiple torque sources (propulsion source, clutch, and wheel brake) to generate vehicle yaw moment. Instead of relying solely on engine torque through clutch application, the system merges propulsion torque, clutch torque capacity, and brake torque to achieve yaw moment generation across all driver demand conditions, including when engine torque is low or zero.
Solution Approach 2:
The system enables the axle/differential system to perform multiple functions: it can generate yaw moment using engine torque when available, and alternatively generate yaw moment using wheel brake torque when engine torque is insufficient. This multi-functional approach ensures yaw moment control capability across all operating conditions.
2Force
If clutch torque is used to generate yaw moment, then torque distribution between wheels is controlled, but system complexity increases when multiple torque sources are combined
Solution Approach 1:
The control system automatically determines the appropriate torque source (propulsion source or wheel brake) based on driver demand torque conditions and system state, managing the complexity of coordinating multiple torque sources through intelligent decision-making algorithms that select the most efficient torque application method for each situation.
3Force
If equal and opposite vectoring torques are applied to left and right wheels with propulsion torque, then yaw moment is generated even when driver demand torque is low, but additional torque management is required
Solution Approach 1:
The system continuously monitors driver demand torque, vehicle state, and torque application effectiveness, using this feedback to dynamically adjust the proportion of propulsion torque versus brake torque applied to each wheel. This ensures optimal yaw moment generation while maintaining simplicity in torque management across varying operating conditions.
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
This approach allows for vehicle yaw moment control regardless of driver demand wheel torque levels, both low and high, and can be applied to existing vehicle systems, including electric, hybrid, and internal combustion engine vehicles, enabling yaw moment generation even without driver input.
Implementation Method 1
increasing a torque applied via a wheel brake in response to the increase in vectoring torque
Data Source
AI summary
Methods and systems are provided for controlling yaw of a vehicle while maintaining vehicle speed. In one example, equal and opposite vectoring torques are applied to first and second wheels along with a propulsion torque so that a vehicle yaw moment may be induced without accelerating or decelerating the vehicle.