BLDC Motor Electronics Cooling With Integrated Radial Impeller
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Solution Overview
Problem
Existing fan units for cooling automobile engine cooling systems face challenges in effectively cooling integrated electronics without increasing space, especially when using brushless electric motors with high heat generation, as they rely on natural convection and bulky designs that are not compact or efficient.
Innovation Solution
A fan unit design featuring a brushless motor with a stator shaft and radially arranged rotor, a heat sink with heat fins, and a radial impeller integrated into the fan hub, which enhances airflow by pushing air radially outward and creating suction to improve heat transfer from the electronics, while maintaining a compact form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If electronics are integrated into the motor housing with heat fins, then heat transfer surface area is increased within available volume, but heat transfer efficiency remains limited due to reliance on natural convection in low airflow regions
Solution Approach 1:
The patent combines the fan unit and heat sink into a single integrated assembly where the fan hub directly incorporates the heat sink with heat fins. This merging allows the high-velocity airflow generated by the fan to directly impinge on the heat fins, transforming the heat transfer mechanism from natural convection to forced convection, thereby significantly improving heat transfer efficiency while maintaining compact dimensions.
Solution Approach 2:
The patent introduces an intermediary airflow path where the fan blades generate high-velocity air flow that is channeled through the heat sink structure. This intermediary airflow acts as a mediator between the heat-generating electronics and the surrounding environment, enabling efficient heat removal without requiring large surface areas or bulky configurations.
2Temperature
If ECU is placed externally in a box exposed to high velocity air stream, then cooling effectiveness is improved, but electromagnetic emissions increase and airflow efficiency decreases
Solution Approach 1:
The patent merges the ECU housing with the motor housing, creating an integrated assembly where the electronics are positioned within the motor housing and cooled by the fan-generated airflow. This eliminates the need for a separate external ECU box, thereby reducing electromagnetic emissions and improving airflow efficiency while maintaining effective cooling through the integrated heat sink.
3Reliability
If large surface area heat fins are used for natural convection cooling, then heat transfer capacity is increased, but the design becomes bulky and space-consuming
Solution Approach 1:
The patent replaces the natural convection mechanism with a mechanically-driven forced convection system using a fan. This substitution allows the heat sink to operate efficiently with a compact surface area, as the fan provides the necessary airflow to remove heat effectively, eliminating the need for large, bulky heat fins required for passive cooling.
4Temperature
If radial heat fins protrude into main fan airflow, then cooling efficiency is improved, but the design becomes heavy and bulky
Solution Approach 1:
The patent nests the heat sink within the fan hub structure, with the heat fins arranged radially within the available space of the fan assembly. This nested configuration allows the heat fins to be positioned in the high-velocity airflow path without adding significant external dimensions or weight, as the heat sink utilizes the existing volume of the fan hub.
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 heat transfer efficiency from the electronics, allowing for effective cooling without the need for large surface areas or bulky components, thus maintaining compactness and reducing complexity in mounting and airflow interference.
Implementation Method 1
the fan unit hub further comprises a radial impeller that is located adjacent to the heat fins of the impeller. The impeller adjacent to the heat fins enhances the air flow at the heat fins of the ECU by pushing the air radially outwards, thereby sucking the air out of the heat fins and generating proper air movement right at the heat sink.
Implementation Method 2
the mechanism of heat transfer is mainly by natural convection, which is the energy transfer from a surface due to the local heating up of the surrounding fluid which is slowly set into motion as it heats up.
Implementation Method 3
a heat sink adjacent to the stator shaft comprising electronic components in particular for controlling the electric motor and comprising heat fins fixed to the circumference of the heat sink
Data Source
AI summary
A fan unit for a cooling system in an automobile, comprises an electric motor comprising a rotor and a stator, wherein the stator is formed in the centre of the electric motor and the rotor is arranged radially outwards around the stator, a heat sink adjacent to the stator shaft comprising electronic components comprising heat fins fixed to the circumference of the heat sink and a fan hub, fixedly connected to the rotor of the electric motor and located radially outwards of the rotor, the fan hub extends in the direction of the heat sink and comprises fan blades to generate an air flow, wherein the fan hub further comprises a radial impeller that is located adjacent to the heat fins of the impeller.