Undercarriage Panelling Flow Separation for Rear Axle Drag Reduction
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Solution Overview
Problem
Conventional undercarriage panelling designs for vehicles often result in suboptimal aerodynamics due to air flow blockages around the rear axle, leading to increased air resistance and lift, which affects fuel efficiency and CO2 emissions.
Innovation Solution
An undercarriage panelling element with a first and second air guidance region, where the second region is angled rearwards and features a flow separation edge that directs air upwards and accelerates it, causing a clear separation from the panelling, thereby guiding air around the rear axle and diffuser for improved aerodynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional undercarriage panelling is used to cover the vehicle undercarriage, then the undercarriage is protected and covered, but aerodynamic performance deteriorates due to increased air resistance and lift
Solution Approach 1:
The undercarriage panelling is divided into multiple functional regions: a first air guidance region with substantially even configuration, a second air guidance region angled away from the first, and a flow separation edge region. This segmentation allows each region to perform its specific aerodynamic function while maintaining manufacturing feasibility through modular design approaches.
Solution Approach 2:
Different regions of the panelling are designed with locally optimized geometries: the first air guidance region has a substantially even configuration for stable airflow, the second air guidance region is angled to accelerate and direct airflow upward, and the flow separation edge is positioned to create controlled flow separation. Each local geometry is tailored to achieve specific aerodynamic effects at that location.
2Object-affected harmful factors
If the second air guidance region is angled away from the first air guidance region to form a ramp-like structure, then airflow is accelerated upwards improving aerodynamics, but the panelling structure becomes more complex
Solution Approach 1:
The second air guidance region is configured as a ramp-like structure angled away from the first air guidance region, creating a curved or inclined surface that smoothly accelerates airflow upward. This curved geometry promotes attached flow and reduces turbulence compared to sharp angles, while still achieving the desired aerodynamic effect of directing airflow over the rear axle and diffuser.
Solution Approach 2:
The panelling design transitions from a substantially two-dimensional even surface in the first air guidance region to a three-dimensional angled ramp structure in the second air guidance region. This dimensional change allows the panelling to actively manipulate airflow direction and velocity, creating upward acceleration and controlled flow separation to improve aerodynamic performance.
3Force
If a flow separation edge is attached to the second air guidance region to direct and separate airflow, then lift on the rear axle is reduced, but the panelling structure becomes more complex
Solution Approach 1:
The flow separation edge is designed as a distinct, separable feature attached to the second air guidance region. This extracted element specifically performs the function of creating controlled flow separation to reduce lift on the rear axle, while being manufacturable as a separate component or attachment feature that simplifies the overall manufacturing process.
Solution Approach 2:
The flow separation edge acts as an intermediary element between the second air guidance region and the rear axle/diffuser area. It mediates the airflow by creating a controlled separation that directs flow away from the rear axle, thereby reducing lift forces without requiring direct modification of the rear axle or diffuser structures.
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
This design enhances aerodynamics by reducing lift and air resistance, improving fuel efficiency, and allowing for a greater ride height, while ensuring air flows effectively over the rear axle and diffuser, thus minimizing CO2 emissions.
Implementation Method 1
The second air guidance region angled away from the first air guidance region extends away from underneath the front to above the back of the first air guidance region in the longitudinal direction of the vehicle
Implementation Method 2
a flow separation edge that is attached, in particular directly, to the second air guidance region, and that is arranged behind the second air guidance region or on its end region in the longitudinal direction of the vehicle
Data Source
AI summary
An undercarriage panelling element of a vehicle includes a first air guidance region, a second air guidance region that is attached to the first air guidance region rearwards in a longitudinal direction of the vehicle and angled away from the first air guidance region, and a flow separation edge that is attached to the second air guidance region. The flow separation edge is disposed behind the second air guidance region in the longitudinal direction of the vehicle and extends downwards away from the second air guidance region over its entire extension running in a vertical direction of the vehicle in parallel or obliquely to the vertical direction of the vehicle, A rear axle of the vehicle on which wheels are mounted is disposed behind the undercarriage panelling element in the longitudinal direction of the vehicle.