Underbody Air-Guiding Device for Pitching Moment Control
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Solution Overview
Problem
Existing motor vehicle cooling systems face challenges in optimizing cooling air supply to the radiator while minimizing aerodynamic drag and pitching moment, which can affect driving performance and fuel efficiency.
Innovation Solution
An adjustable air-guiding device on the underbody, between the radiator and wheel guard, that changes its air-guiding surface between convex and level positions to control airflow and reduce aerodynamic drag, with a control system coordinating the radiator shutter flaps and air ducts to maintain balanced pitching moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the radiator shutter is closed to reduce aerodynamic drag, then fuel consumption decreases, but front wheel lift force increases causing severe change in lift balance and driving performance
Solution Approach 1:
The air-guiding device is positioned to preemptively counteract the front wheel lift force generated by the closed radiator shutter. By guiding airflow to generate downward force on the front axle, the system pre-compensates for the destabilizing effect before it significantly impacts driving performance, allowing the radiator shutter to remain closed for fuel efficiency.
Solution Approach 2:
The air-guiding device acts as an intermediary between the radiator shutter and the front wheel assembly. It modifies the airflow pattern created by the closed shutter to produce beneficial aerodynamic forces, transforming the harmful lift force into a stabilizing downward force that maintains driving performance while enabling energy-efficient operation.
2Loss of energy
If cooling air flaps are closed to reduce aerodynamic drag, then fuel consumption decreases, but cooling air supply to the radiator is reduced
Solution Approach 1:
The system employs dynamically adjustable cooling air flaps that can be positioned in intermediate states between fully open and fully closed. This allows the radiator shutter to maintain a closed position for reduced drag while the flaps modulate airflow to provide sufficient cooling, enabling continuous optimization of the trade-off between fuel consumption and cooling efficiency based on real-time operating conditions.
3Reliability
If the air-guiding device is in the open position to supply cooling air to wheel brakes, then braking performance improves, but aerodynamic drag increases
Solution Approach 1:
The air-guiding device operates periodically, switching between open and closed positions based on operational requirements. During braking operations, it opens to supply cooling air to the wheel brakes; during cruising, it closes to minimize aerodynamic drag. This periodic action allows the system to achieve both braking performance and fuel efficiency at different times in the operating cycle.
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 solution reduces aerodynamic drag and fuel consumption by dynamically adjusting airflow, compensating for lift changes and enhancing driving dynamics, particularly during racing conditions.
Implementation Method 1
In the open position, the air guiding device curves upward to define a downwardly convex air-guiding surface that opens the flow duct. The air-guiding device that is in the open position forms the upwardly curved, convex air-guiding surface that opens the downwardly U-shaped flow duct and can supply an upward air flow, for example, to cool the wheel brakes. The reaction force of the upward air flow reduces the front axle lift.
Implementation Method 2
The air-guiding device that is in the lowered closed position forms the level air-guiding surface and closes the flow duct. The front axle lift increases in this position and the aerodynamic drag is reduced, i.e. the front axle lift is higher and the aerodynamic drag is lower than in the open position with the convex air-guiding surface.
Data Source
AI summary
A motor vehicle has at least one adjustable air-guiding device on the underbody. The air-guiding device has a cross-sectionally U-shaped duct and is adjustable between a closed position and an open position. The motor vehicle also has a radiator device with a radiator and a radiator shutter with adjustable flaps for controlling the air flow through the radiator. A control device actuates the air-guiding device depending on the position of the radiator shutter so that, irrespective of the position of the flaps of the radiator shutter, an at least approximately identical pitching moment is obtained at the motor vehicle and at the same time the aerodynamic drag is reduced.