Heavy-Duty Differential Brake Control for Split-Friction Traction
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Solution Overview
Problem
Current traction control systems in heavy-duty vehicles are suboptimized for real-world road conditions, leading to excessive braking and worsening traction conditions due to inaccurate detection of split friction between wheels.
Innovation Solution
A method for controlling a powertrain system that dynamically adjusts brake force based on the target wheel slip of the high-friction side, using wheel slip as an input parameter to improve traction control and reduce wheel slip on the low-friction side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current traction control systems are calibrated based on unrealistic scenarios (asphalt/polished ice or basalt), then the system can provide theoretical traction control, but the system provides excessive braking in real-world conditions causing ground tearing and worsened traction
Solution Approach 1:
The system dynamically adjusts the wheel slip threshold parameter from a fixed calibrated value to a variable that adapts to actual road conditions. By monitoring real-time wheel slip differences between left and right sides, the system modifies the threshold parameter to match actual friction conditions rather than relying on unrealistic calibration scenarios, thereby preventing excessive braking while maintaining effective traction control
Solution Approach 2:
The system implements continuous feedback by monitoring wheel speeds and calculating wheel slip differences between left and right sides. This feedback loop allows the system to detect actual split-friction conditions and adjust brake force application accordingly, preventing the ground tearing effect caused by excessive braking while maintaining traction control effectiveness
2Ease of operation
If a differential arrangement allows wheel speeds to differ between left and right sides during split friction conditions, then the wheels can rotate at different speeds, but torque transfer to the high-friction side is limited
Solution Approach 1:
The system applies different brake forces to different wheels based on their individual friction conditions. By identifying which side is experiencing low friction through wheel slip monitoring, the system selectively applies braking only to the low-friction side, allowing the high-friction side to maintain optimal torque transfer and wheel slip for maximum traction
Solution Approach 2:
The traction control system is segmented into independent left and right side control channels. Each side's brake force is controlled independently based on its specific friction conditions, allowing the system to optimize torque distribution to the high-friction side while preventing spin on the low-friction side
3Reliability
If traction control systems apply excessive brake force to stop wheel spin, then wheel slip is reduced, but energy consumption increases and response time is delayed
Solution Approach 1:
Instead of applying full brake force to completely stop wheel spin, the system applies only the partial brake force necessary to maintain wheel slip within the optimal range. By using the wheel slip threshold as a guide, the system applies just enough braking to prevent excessive spin while preserving energy and maintaining responsive control
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
Enhances traction force transfer and improves vehicle performance by accurately managing brake force and propulsion unit speed, reducing wheel slip and energy consumption in split-friction conditions.
Implementation Method 1
the spinning wheel(s) of one or more wheel shafts of the vehicle may generally need to be braked in order to transfer torque to a high friction side
Data Source
AI summary
A method for controlling a powertrain system of a heavy-duty vehicle, the powertrain system having at least one differential arrangement for receiving torque from a propulsion unit of the powertrain system and delivering at least a part of the torque to a set of first and second wheels, the method being implemented by a control unit, the method comprising determining a split-friction condition indicative of a wheel slip difference between the first and second wheels, wherein one of the first and second wheels defines a high-friction side of the differential arrangement and the other one of the first and second wheels defines a low-friction side of the differential arrangement; determining a target wheel slip for the high-friction side; and in response to the determined split-friction condition; controlling a brake force on the low-friction side of the differential arrangement based on the target wheel slip on the high-friction side.