Shape-Memory Wheel Insert for Brake Cooling and Low Drag

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Solution Overview

Problem

Conventional aerodynamic hubcaps for motor vehicle wheels provide limited air flow to the braking system, leading to increased brake temperatures and aerodynamic drag, while existing solutions either compromise aerodynamics or are difficult to install and disassemble.

Innovation Solution

An insert for the wheel featuring a frame with a blade pivotally mounted on a metal support with shape memory, which changes orientation based on temperature, directing air flow either inward for cooling or outward to reduce drag, with a calibrated return spring mechanism for smooth movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If aerodynamic hubcaps with blades are used to reduce drag, then aerodynamic performance is improved, but air flow to braking system is limited

Engineering Contradiction:
Improveaerodynamic dragVSAvoidbrake temperature
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The blade is made movable through a shape memory alloy support that allows it to pivot between different orientations. At low temperatures, the blade adopts an aerodynamic orientation to reduce drag. When brake temperature exceeds the critical threshold, the shape memory alloy transforms, causing the blade to pivot to an open position that maximizes air flow to the braking system, thus dynamically resolving the contradiction between drag reduction and brake cooling.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system utilizes temperature as a controlling parameter to switch between two operational states. The shape memory alloy support has a predetermined critical temperature that triggers a phase transformation, changing the blade's orientation from a closed aerodynamic position to an open cooling position. This parameter-based control automatically balances aerodynamic performance and thermal management based on real-time brake temperature conditions.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If wheel vents are closed to improve aerodynamics, then aerodynamic drag is reduced, but brake ventilation is insufficient

Engineering Contradiction:
Improveaerodynamic dragVSAvoidbrake cooling efficiency
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The blade system is self-regulating through the shape memory alloy support. When brake temperature rises, the alloy automatically transforms and pivots the blade to open the vent, allowing air to cool the brakes. When temperature drops, the alloy returns to its original state, closing the vent to restore aerodynamic efficiency. This self-service mechanism eliminates the need for external actuators or control systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements thermal feedback control where the blade position is determined by the brake temperature. The shape memory alloy support senses the temperature condition and automatically adjusts the blade orientation accordingly, creating a closed-loop control system that continuously optimizes the balance between aerodynamic drag and brake cooling based on real-time thermal conditions.

Inventive Principle:
Principle #23Feedback

3Loss of energy

If shape memory actuators are used to control blade orientation, then aerodynamic and thermal performance are optimized, but device complexity increases

Engineering Contradiction:
Improveaerodynamic dragVSAvoidactuator mechanism complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The invention extracts the control mechanism from complex multi-component actuators and reduces it to a single shape memory alloy support element. This alloy support directly provides both the structural function of holding the blade and the actuation function of pivoting the blade in response to temperature changes, eliminating the need for separate motors, sensors, and control electronics.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system exploits the inherent phase transformation property of shape memory alloys at a predetermined critical temperature to achieve automatic blade actuation. This material-based parameter change replaces complex mechanical or electronic control systems, reducing device complexity while maintaining the ability to optimize both aerodynamic and thermal performance based on brake temperature conditions.

Inventive Principle:
Principle #35Parameter changes

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

Optimizes both aerodynamics and brake cooling, achieving a 3 dm2 aerodynamic gain and a 1.5 g CO2 reduction per kilometer, while reducing brake fluid temperature by approximately -10°C, and is simple to implement.

Implementation Method 1

a blade (4) linked to the frame (3), said blade (4) being pivotally mounted on the frame (3) by means of a support (5) formed by a shape memory metal element configured to modify the orientation of said blade (4) from a predetermined critical temperature

Methodology Applied
Scientific EffectShape memory metal effect: Shape Memory Alloy

Data Source

PatentEP4259452B1Optimized aerodynamic insert for a vehicle wheel
Publication Date: 2024.08.07 STELLANTIS AUTO SAS
  • EP4259452B1 patent drawingFigure 1~2
  • EP4259452B1 patent drawingFigure 3~4a
  • EP4259452B1 patent drawingFigure 4b

AI summary

The invention relates to an insert (1) for a wheel (2) of a motor vehicle, comprising a frame (3) designed to be solidly attached in an opening (22) of the disc (21) of the wheel (2) and at least one blade (4) connected to the frame (3), the blade (4) being pivotably mounted on the frame (3) by means of a shape-memory metal support (5), the blade (4) and the support (5) being positioned on the frame (3) so as to extend and to pivot in a direction that is radial to the disc (21) of the wheel (2) when the device is solidly attached in the opening (22), the two ends (51) of the support (5) being solidly attached to the frame (3), extending on either side of the blade (4) and a central portion (52) of the support (5) being constrained to rotate as one with the blade (4).