Dynamic Fifth Wheel Gap Control for Tractor-Trailer Drag Reduction
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Solution Overview
Problem
Current tractor-trailer configurations face challenges in minimizing aerodynamic drag due to the gap between the tractor and trailer, especially during turns, as existing methods for adjusting the fifth wheel position or deploying fairings are either static or not dynamically responsive to changing articulation angles and turning radii.
Innovation Solution
A method is introduced to calculate the turning radius and articulation angle of a towing and towed vehicle system that allows horizontal articulation, using rotational velocity measurements of outer and inner wheel groups and a processor-executed algorithm to control gap treatment devices like fairings, ensuring precise deployment and retraction based on dynamic steering conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the gap between tractor and trailer is minimized to reduce aerodynamic drag, then fuel efficiency improves, but the risk of trailer body hitting tractor cab increases during turns
Solution Approach 1:
The fifth wheel position is made dynamically adjustable during travel, allowing the system to optimize gap size based on real-time operating conditions. The adjustment mechanism enables transition between minimal gap (for drag reduction) and larger gap (for safety during articulation), resolving the contradiction between energy efficiency and collision avoidance
Solution Approach 2:
The system uses feedback from articulation angle sensors and turning radius calculations to automatically adjust fifth wheel position. When articulation angle indicates upcoming turn, the system proactively increases gap; during straight travel, it minimizes gap for drag reduction, creating a closed-loop control that balances both objectives
2Loss of energy
If fifth wheel position is adjusted to optimize gap size, then aerodynamic drag reduces, but device complexity increases due to adjustment mechanism
Solution Approach 1:
The adjustment mechanism serves multiple functions: it positions the fifth wheel for optimal gap during straight travel, and also positions it to prevent collision during turns. This multi-functionality justifies the added complexity by delivering dual benefits of drag reduction and safety
Solution Approach 2:
The system uses the tractor's existing steering input and articulation angle data to automatically control fifth wheel adjustment, eliminating need for separate sensors or complex control systems. The adjustment mechanism serves itself by utilizing already-available vehicle operational data
3Loss of energy
If fairings are deployed to reduce aerodynamic drag, then fuel efficiency improves, but device complexity and deployment control difficulty increase
Solution Approach 1:
Fairing deployment is made dynamic rather than static, with automatic deployment/retraction based on real-time turning radius and articulation angle detection. The system deploys fairings only when conditions are safe (large turning radius), and retracts when turning radius decreases, optimizing drag reduction while managing complexity through conditional automation
Data Source
AI summary
Turning radius of a tractor-trailer is calculated by certain dimensional relationships in the tractor-trailer and rotational velocities of axle wheel groups.