Air Suspension Load Calculation Using Track Width Correction
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Solution Overview
Problem
Existing vehicle load detection systems for air suspension systems in automotive vehicles suffer from limited accuracy due to the neglect of forces affecting the vehicle frame and corner assemblies, leading to inaccurate load calculations and potential damage to air springs and false operations of dynamic stability control systems.
Innovation Solution
A vehicle load calculation system that incorporates pressure sensors and height sensors to determine a first load value, adjusts for changes in track width by subtracting a second load value based on track width changes, and applies a coefficient of road surface friction to a constant stiffness factor to correct the load detection, ensuring accurate load determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only pressure sensor and height sensor signals are used to determine vehicle load, then the calculation is simple, but the measurement precision is limited due to neglecting forces affecting the vehicle frame and corner assemblies
Solution Approach 1:
The load calculation is segmented into two distinct components: a first load value calculated from pressure and height sensors, and a second load value calculated from track width changes. This segmentation allows each component to address specific aspects of the load calculation independently, improving overall accuracy while maintaining manageable complexity.
Solution Approach 2:
The invention introduces track width measurement as an additional dimension to the traditional load calculation. By measuring changes in track width and converting them to a load equivalent, the system captures forces that were previously invisible to the load calculation, thereby improving measurement precision without excessive complexity.
2Measurement precision
If track width changes are incorporated into load calculation, then the measurement precision improves, but the device complexity increases due to additional sensors and calculations
Solution Approach 1:
The height sensors already present in the air suspension system serve dual purposes: measuring ride height for suspension control and providing data for track width calculation. This multi-functionality allows the system to improve load detection accuracy without adding dedicated sensors solely for track width measurement.
Solution Approach 2:
The electronic control unit acts as an intermediary that processes height sensor data to derive track width changes, rather than requiring direct track width sensors. This approach uses existing infrastructure to achieve the measurement, reducing the need for additional hardware components.
3Ease of operation
If inaccurate vehicle load detection is used, then the system operation is simple, but harmful factors increase due to potential air spring damage and false stability control operations
Solution Approach 1:
The system applies a correction value derived from track width changes to compensate for measurement errors before making suspension adjustments. This beforehand cushioning prevents excessive or incorrect air spring pressure changes that could lead to damage, while maintaining straightforward system operation.
Solution Approach 2:
The system continuously monitors track width changes and uses this feedback to adjust the load calculation in real-time. This feedback mechanism ensures that the suspension system responds accurately to actual vehicle conditions, preventing harmful operations while maintaining ease of use through automated control.
Data Source
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AI summary
A method of calculation a vehicle load comprising calculating a first vehicle load value based at least on air pressures in air springs and height data of suspension of a vehicle axle, determining a second vehicle load value based on a change of track width of the vehicle axle, and calculating the vehicle load based on the first vehicle load value and the second vehicle load value.