AWD Torque Gradient Control for Smooth Dual-Motor Transitions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Road-coupled all-wheel drive vehicles experience discomfort due to jolts during dynamic torque changes, as existing control systems fail to smoothly distribute torque between primary and secondary electric drive motors, leading to inefficient and uncomfortable transitions between single-axle and dual-axle operations.
Innovation Solution
A control device with a gradient-limiting module that abruptly adjusts the target all-wheel drive factor and limits the torque gradient of the primary and secondary motors, ensuring the primary motor's torque remains constant while the secondary motor adjusts to maintain a smooth and efficient torque distribution, preventing counter-gradient adjustments and undefined gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the target all-wheel drive factor is adjusted quickly to respond to driver input, then the responsiveness and performance of the vehicle is improved, but abrupt torque changes cause jolts and reduce comfort
Solution Approach 1:
The control system dynamically adjusts the torque distribution between primary and secondary motors based on the driver-input gradient. When the driver requests torque changes, the system responds quickly by adjusting the all-wheel drive factor, but simultaneously limits the torque gradient to prevent abrupt changes that would cause jolts. This dynamic balancing act allows the system to be both responsive and comfortable.
Solution Approach 2:
The system changes the target all-wheel drive factor parameter abruptly to match driver intent, but controls the torque gradient parameter to prevent excessive rates of change. By separating these two parameter adjustments - allowing the drive factor to change quickly while limiting the actual torque gradient - the system achieves both responsiveness and comfort.
2Productivity
If the primary motor torque is adjusted rapidly to meet target torque requirements, then the productivity and response time are improved, but the torque gradient becomes undefined or counter-gradient causing instability
Solution Approach 1:
The control system continuously monitors the driver-input gradient and uses this feedback to adjust the torque distribution. The gradient-limiting module compares the current torque gradient with the driver-input gradient and makes real-time adjustments to prevent counter-gradient situations. This feedback mechanism ensures that torque adjustments remain stable and aligned with driver intent.
Solution Approach 2:
The gradient-limiting module preemptively prevents counter-gradient torque adjustments by limiting the maximum permissible torque gradient before such situations can occur. Rather than reacting to instability after it occurs, the system proactively constrains the torque gradient to remain within stable, physically meaningful bounds.
3Use of energy by moving object
If the system operates solely with the primary motor in efficiency-optimized mode, then the energy efficiency is improved, but the performance and adaptability during dynamic driving conditions deteriorate
Solution Approach 1:
The system dynamically transitions between single-axle and dual-axle operation based on driving conditions. During steady-state efficient driving, it operates in single-axle mode to maximize energy efficiency. When dynamic conditions arise (detected through driver-input gradient), it quickly engages the secondary motor while limiting the torque gradient to ensure smooth transitions. This dynamic adaptability allows the system to optimize both efficiency and performance.
Data Source
AI summary
The invention relates to a control device for operating a road-coupled all-wheel drive vehicle having at least one electronic control unit, having at least a first drive motor as a primary motor assigned to a primary axle and having at least a second drive motor as a secondary motor assigned to a secondary axle. According to the invention, the control unit has a gradient-limiting module for performing a torque gradient limiting function in such a manner that, in the event of a change of the target all-wheel drive factor on the basis of a defined driver's request signal, first the new target all-wheel drive factor is predetermined in a sudden manner and second, in the course of the subsequent adjustment of the all-wheel drive factor, the gradient of the driver's request signal forms the gradient limitation for the maximum admissible adjustment of the torque of the primary motor and/or secondary motor.