Vehicle Combination Drag Prediction Under Crosswind Shape Changes
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Solution Overview
Problem
Current methods for predicting the drag area of a vehicle combination are inadequate when the exterior shape changes, as they require costly wind tunnel tests or numerical simulations, and online estimation is only applicable after the change has occurred, making it difficult to accurately predict energy consumption before changes in configuration, such as adding or removing trailers, during a transport mission.
Innovation Solution
A method that predicts the drag area of a vehicle combination by obtaining and rescaling drag and projected area functions based on air-attack angle, allowing for hypothetical changes in exterior shape without the need for actual changes, using geometrical attributes to estimate the second projected area, thus enabling advanced prediction of energy consumption before changes occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wind tunnel tests or numerical simulations are performed to obtain accurate drag area data for a changed exterior shape, then measurement precision is improved, but loss of time and loss of substance increase due to the costly and tedious nature of these tests
Solution Approach 1:
The patent performs wind tunnel tests or numerical simulations in advance to obtain drag area functions for a reference exterior shape. These pre-acquired data are stored and can be rapidly scaled for different configurations, eliminating the need to repeat costly tests for each new exterior shape while maintaining measurement precision through the use of established aerodynamic relationships
Solution Approach 2:
The patent creates a mathematical model (drag area function) that represents the aerodynamic characteristics of the vehicle combination. This model can be scaled and adapted to different exterior shapes through rescaling operations, serving as a virtual copy that replaces the need for physical re-testing while preserving the essential aerodynamic behavior
2Loss of time
If on-line estimation is used to obtain drag area data after exterior shape changes, then loss of time is reduced, but the ability to predict energy consumption in advance is lost
Solution Approach 1:
The system pre-acquires drag area functions through wind tunnel tests or simulations for a reference configuration. These pre-computed models enable both rapid online estimation and advance prediction capabilities, as the foundational aerodynamic data are already available before any configuration changes occur
Solution Approach 2:
The patent uses parameter rescaling techniques to adapt the pre-acquired drag area function to new exterior shapes by changing geometric parameters such as projected area. This allows the system to maintain advance prediction capability while efficiently handling configuration changes through mathematical transformations rather than re-testing
3Measurement precision
If wind tunnel tests are performed for each new exterior shape configuration, then measurement precision is maintained, but loss of substance increases due to the costly nature of repeated testing
Solution Approach 1:
The patent creates a universal drag area model that can serve multiple exterior shape configurations through rescaling operations. A single set of wind tunnel tests or simulations performed on a reference configuration generates a mathematical model that can be adapted to various derivative configurations, making the expensive testing process universally applicable across multiple scenarios rather than requiring separate tests for each configuration
Solution Approach 2:
The patent creates a mathematical representation (drag area function) that captures the essential aerodynamic characteristics. This virtual model can be replicated and scaled for different configurations without requiring physical duplication through repeated wind tunnel testing, thereby reducing substance loss while maintaining measurement precision
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3A~3B
AI summary
A computer-implement method (200) of predicting a drag area (as function of airattack angle) of a vehicle combination after hypothetically changing an exterior shape of the vehicle combination from a first exterior shape to a second exterior shape is provided. The method includes obtaining (S201) a first drag area function, obtaining (S202) a first projected area function, obtaining (S203) a second projected area function, and predicting (S204) a second drag area function based on a rescaling of the first drag area function by a ratio of the second projected area function to the first projected area function. A corresponding device, vehicle or vehicle combination, computer program and computer program product are also provided.