EPAS Motor Cooling System Using Active Fluid Circulation
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Solution Overview
Problem
Electric Power Assisted Steering (EPAS) systems face temperature threshold issues during high-demand conditions, such as off-roading or high-speed driving, leading to potential system failure due to inadequate cooling methods.
Innovation Solution
An automatic cooling system that utilizes sensors to detect temperature and other parameters, activating a cooling cycle by moving water or liquid coolant from a reservoir through a heat sink to prevent the EPAS motor from exceeding a temperature threshold, using condensation or windshield washer fluid, and maintaining a minimum fluid level to ensure continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ambient air flow is used to cool the EPAS system, then the system can avoid exceeding temperature threshold, but the cooling effectiveness is insufficient under high-demand conditions
Solution Approach 1:
The patent introduces a coolant (water or liquid coolant) as an intermediary substance to transfer heat from the EPAS motor to a heat sink. The coolant circulates through channels in the motor housing, absorbing heat and carrying it away, thereby providing more effective cooling than ambient air flow alone under high-demand conditions.
Solution Approach 2:
The patent employs a liquid cooling system where coolant flows through hydraulic channels integrated into the motor housing. This hydraulic cooling approach provides superior heat removal capability compared to passive air cooling, enabling the system to maintain safe temperatures during extended high-load operation.
2Temperature
If current in the EPAS system is reduced to zero to avoid exceeding temperature threshold, then temperature can be controlled, but steering assistance is lost
Solution Approach 1:
The patent implements proactive cooling measures by circulating coolant through the motor housing before the temperature reaches critical thresholds. Temperature sensors monitor the motor continuously, and the cooling system activates in advance to prevent overheating, allowing the EPAS system to maintain full current and steering assistance without interruption.
Solution Approach 2:
The patent ensures continuous cooling operation during extended high-demand conditions by maintaining coolant circulation throughout the motor housing. This continuous heat removal enables the EPAS system to sustain full operating current and provide uninterrupted steering assistance, eliminating the need to reduce current to zero.
3Temperature
If water or liquid coolant is moved from a reservoir through a heat sink, then effective cooling is achieved, but system complexity increases
Solution Approach 1:
The patent integrates the cooling channels directly into the motor housing structure, merging the cooling system with the existing motor assembly. The coolant channels are formed as part of the housing itself rather than as separate components, reducing overall system complexity while providing effective cooling.
Solution Approach 2:
The patent uses the existing motor housing to serve dual functions: structural containment of motor components and heat transfer pathway for the coolant. This multi-functionality eliminates the need for separate cooling jackets or housings, simplifying the overall system design while maintaining effective cooling capability.
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
The system effectively maintains the EPAS motor within safe temperature limits during extreme use conditions, ensuring continuous operation and preventing system failure without reducing the current drawn by the EPAS system, thus providing full steering output even under high load and high temperature scenarios.
Implementation Method 1
As the fluid moves through the channel, heat is transferred away from the electric motor
Implementation Method 2
moving water or a liquid coolant from a reservoir through a heat sink coupled to an interior or exterior of the EPAS system
Data Source
AI summary
The present disclosure is directed to a cooling system for a system, such as an electric power assisted steering (EPAS) system and the components of such system, such as a motor. The cooling system includes a temperature sensor coupled to an electric motor of the EPAS system, one or more fluid reservoirs, and a fluid transfer device coupled to the motor and to the first fluid reservoirs. The fluid transfer device extends along a length of the motor. The cooling system further includes a pump coupled to the fluid reservoir and the fluid transfer device, a control unit coupled to the sensor and the pump. The control unit is configured to activate the pump in response to temperature detected by the sensor being greater than or equal to a first threshold motor temperature. The pump transfers the fluid in the fluid reservoirs to the fluid transfer device for absorbing the heat of the motor. The fluid transfer device is configured to contain the transferred fluid.