Hybrid Vehicle Cooling System Rotor Submersion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional cooling systems for hybrid vehicles disrupt the rotation of high-frequency operating motors due to intermittent oil pump operation, causing stirring resistance when the rotor becomes submerged in oil.
Innovation Solution
A cooling system configuration where the motor is positioned downstream of the pressurizing unit and the generator is positioned downstream of the motor and upstream of the pressurizing unit in the coolant recirculating direction, ensuring the rotor remains unsubmerged and minimizing stirring resistance, even when the oil pump is stopped.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the oil pump is operated intermittently to cool the motor and generator, then energy consumption is reduced, but the rotor becomes submerged in oil causing stirring resistance that disturbs rotation
Solution Approach 1:
The patent segments the cooling system into two independent circuits: an oil cooling circuit for the motor and a water cooling circuit for the generator. This allows the oil pump to be operated intermittently for energy savings while the generator is cooled by a separate water circulation system, eliminating the stirring resistance problem that occurred when oil submerged the motor rotor.
Solution Approach 2:
The patent introduces a water cooling circuit as an intermediary system to cool the generator separately from the oil cooling circuit. This mediator system allows the generator to be cooled without using oil, thereby preventing the rotor submersion and stirring resistance issues while maintaining effective thermal management.
2Device complexity
If the motor and generator are cooled by a common oil cooling system, then system complexity is reduced, but the rotor submersion in oil causes stirring resistance and rotational disturbance
Solution Approach 1:
The patent divides the cooling system into separate oil and water cooling circuits, with the oil circuit serving the motor and the water circuit serving the generator. This segmentation eliminates the harmful interaction where oil would submerge and resist the rotating rotor, while the added circuit complexity is justified by the elimination of operational disturbances.
3Temperature
If the oil level in the oil reservoir is high to ensure adequate cooling, then cooling effectiveness is improved, but the rotor becomes submerged in oil when the pump is stopped causing stirring resistance
Solution Approach 1:
The patent separates the cooling functions into independent oil and water circuits, allowing the oil reservoir level to be optimized for motor cooling without concern for rotor submersion issues. The generator cooling is handled by the water circuit, eliminating the conflict between adequate cooling and rotor submersion problems.
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 allows for efficient cooling of high-frequency operating motors without disturbing their rotation and reduces temperature variations in the generator, enhancing overall cooling efficiency and stability.
Implementation Method 1
a cooling path in which a coolant for cooling the motor and the generator is recirculated
Implementation Method 2
a pressurizing unit configured to pump the coolant
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A cooling system to be mounted in a hybrid vehicle including a motor driven and a generator includes a cooling path and a pressurizing unit. In the cooling path, coolant for cooling the motor and the generator is recirculated. The pressurizing unit pumps the coolant. The motor is disposed downstream of the pressurizing unit in a recirculating direction of the coolant. The generator is disposed downstream of the motor and upstream of the pressurizing unit in the recirculating direction.