Hubless Motor Vehicle Fan Impeller Design
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Solution Overview
Problem
Motor vehicle fans with traditional impellers suffer from performance losses due to a central hub 'dead zone' that reduces airflow efficiency, leading to potential engine overheating and air conditioner malfunctions, while also being inefficient in energy consumption and prone to noise and vibration issues, especially in vehicles with limited space under the hood.
Innovation Solution
The design of an impeller without a central hub, featuring a cylindrical ring with blades extending towards the center, where all blade root ends are free, allowing for improved airflow and reduced turbulence, and utilizing a NACA 65(24)10 aerodynamic profile for enhanced performance, along with a central hub of reduced size to maximize agitation area without increasing the impeller's diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a traditional impeller with a central hub is used, then the structure provides support for the blades, but a dead zone is created that reduces airflow efficiency and causes turbulence at the blade roots
Solution Approach 1:
The patent removes the central hub from the impeller structure, extracting the harmful element that creates the dead zone and turbulence. The blades are directly mounted to the impeller body without a central hub, eliminating the obstruction to airflow and the source of turbulence at the blade roots.
Solution Approach 2:
The impeller is segmented into discrete blades mounted directly to the impeller body, rather than being integrated into a solid central hub structure. This segmentation allows airflow to pass through the center region without obstruction while maintaining blade support.
2Productivity
If the impeller diameter is increased to improve fluid agitation performance, then more air can be moved, but electrical energy consumption increases
Solution Approach 1:
The patent changes the geometric parameters of the impeller by eliminating the central hub and optimizing blade dimensions, allowing for more efficient fluid agitation with reduced diameter. The blade cross-sectional area and pitch are optimized to maximize airflow performance per unit diameter, reducing the energy required to move a given volume of air.
Solution Approach 2:
The blade design incorporates varying cross-sectional areas along the blade length, with larger areas near the root for structural support and smaller areas toward the tip for efficient airflow generation. This local optimization allows the impeller to achieve high performance with a smaller overall diameter.
3Use of energy by moving object
If the impeller diameter is decreased to reduce energy consumption, then electrical efficiency improves, but fluid agitation performance becomes inadequate
Solution Approach 1:
The patent optimizes multiple parameters simultaneously including blade cross-sectional area, blade pitch, and blade curvature to maximize the fluid agitation capability of a smaller impeller. These parameter changes allow the reduced-diameter impeller to compensate for the loss of agitation volume through improved aerodynamic efficiency.
Solution Approach 2:
The blade design incorporates curved and twisted geometries that follow the natural flow patterns of air, creating more efficient aerodynamic surfaces. The curved blade profiles generate better lift and reduce drag, allowing smaller impellers to move more air effectively.
4Ease of manufacture
If a conventional impeller design is used, then manufacturing is straightforward, but noise and vibrations increase leading to potential faults
Solution Approach 1:
By removing the central hub, the patent eliminates a major source of vibration and noise generation. The hubless design reduces unbalanced forces and turbulent eddies that occur at the hub-blade interface, resulting in quieter and smoother operation.
Solution Approach 2:
Instead of mounting blades to a central hub, the patent inverts the conventional approach by having blades extend directly from the impeller body perimeter toward the center, with the blade roots free rather than fixed to a hub. This inversion changes the stress distribution and vibration characteristics, reducing noise and vibration.
5Shape
If the front grille size is reduced in modern vehicle design, then aesthetic and aerodynamic performance improve, but space for the fan and impeller sizing becomes constrained
Solution Approach 1:
The patent changes the fundamental geometric parameters of the impeller by eliminating the central hub and optimizing blade configuration, enabling high-performance fluid agitation in a more compact form factor. This allows the fan system to fit within smaller grilles while maintaining adequate airflow performance.
Solution Approach 2:
The patent optimizes the three-dimensional configuration of the blades, using twisted and curved profiles that utilize vertical and radial dimensions more efficiently. This dimensional optimization allows the impeller to achieve high performance in a compact footprint suitable for modern vehicle grilles.
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 configuration enhances airflow efficiency, reduces energy consumption, minimizes noise and vibration, and optimizes airflow to prevent engine overheating and air conditioner malfunctions, while accommodating the space constraints of modern vehicles.
Implementation Method 1
Each blade has an NACA 65(24)10 aerodynamic profile
Implementation Method 2
the blade root ends are free ends... eliminates the dead zone situated along the rotation axis which makes it possible to use all of the volume of the impeller and to increase the volume of fluid agitated by the impeller
Data Source
AI summary
The invention concerns an impeller (1a, 1b, 1c, 1d, 1e, 1f) of a motor vehicle fan comprising:a cylindrical ring (2) having a center (P),blades (3) extending from the cylindrical ring (2) and toward the center (P), each blade (3) having two radially opposite ends (4, 5), referred to as the blade root end (4) and the blade tip end (5), the blade root end (4) being directed toward the center (P) and the blade tip end (5) being secured to the cylindrical ring (2), characterized in that all the blade root ends (4) are free or linked together by a central hub (20) of reduced diameter.