Reversible Oil Pump Motor Cooling for Low-Speed Heat Dissipation
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Solution Overview
Problem
Existing powertrain systems in electric vehicles face challenges in effectively dissipating heat, particularly when the motor stops or operates at low speeds, leading to inefficient heat dissipation for components like the rotor iron core.
Innovation Solution
A powertrain system with an oil pump that reverses and rotates to alternately input coolant into the motor cavity for immersion cooling, utilizing valves and sumps to manage coolant flow, enhancing heat dissipation by immersing motor components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a gear-based coolant lifting system is used in the motor, then heat dissipation can be achieved during high-speed rotation, but heat dissipation becomes ineffective when the motor stops or runs at low speed
Solution Approach 1:
The oil pump is designed to be reversible, allowing it to dynamically change its rotation direction based on operating conditions. During high-speed rotation, it operates in forward mode for spray cooling; during low-speed or stopped conditions, it reverses to enable immersion cooling by filling the motor cavity with coolant, thus adapting to different speed regimes effectively
Solution Approach 2:
The system employs periodic switching between forward and reverse operation of the oil pump. The control unit activates reverse operation during low-speed periods to perform immersion cooling, then switches back to forward operation during high-speed periods, creating a periodic action pattern that ensures continuous effective cooling across varying operating conditions
2Temperature
If the oil pump continuously circulates coolant through the heat exchanger, then heat dissipation efficiency is improved, but the battery pack cannot be heated when heating is needed
Solution Approach 1:
The oil pump's reversible design enables dynamic switching between cooling mode (forward rotation) and heating mode (reverse rotation). The control unit determines the appropriate mode based on thermal management requirements, allowing the system to adaptively switch between heat dissipation and heat transfer to battery functions
Solution Approach 2:
The oil pump serves multiple functions: it acts as a coolant circulation pump for heat dissipation during forward operation, and as a coolant transfer pump for heating the battery during reverse operation. This multi-functionality allows a single device to handle both cooling and heating thermal management requirements
3Power
If the motor is miniaturized to increase power density, then power-to-weight ratio is improved, but heat generation increases and heat dissipation becomes more difficult
Solution Approach 1:
The system utilizes hydraulic cooling with coolant circulation through the oil pump. By employing fluid-based heat transfer and the reversible pump mechanism, efficient heat removal is achieved despite the compact motor size, allowing high power density to be maintained without compromising thermal management
Solution Approach 2:
The reversible operation of the oil pump changes the flow parameters of the coolant system. By switching between forward and reverse modes, the system alters coolant flow direction and distribution patterns, enabling effective heat dissipation from the compact motor components under varying operating conditions
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 cools motor components by immersing them in coolant, improving heat dissipation and reducing friction losses, while also transferring heat to a battery pack for heating, thus maintaining optimal operating conditions.
Implementation Method 1
when the oil pump is reversing, coolant may be input into a motor cavity and accumulate in the motor cavity, so as to cool motor components in an immersion manner
Implementation Method 2
The coolant flows in the coolant channel with the rotation of the rotor iron core. Finally, due to the centrifugal function of the rotation of the rotor iron core, the coolant is sprayed out from the coolant channel to achieve the purpose of heat dissipation
Implementation Method 3
due to the centrifugal function of the rotation of the rotor iron core, the coolant is sprayed out from the coolant channel to achieve the purpose of heat dissipation
Implementation Method 4
transferring heat to a battery pack for heating, thus maintaining optimal operating conditions
Data Source
Figure 1
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Figure 2b
AI summary
This application discloses a powertrain, a vehicle, and a motor cooling method. An oil inlet of a motor communicates with a first end of an oil pump through a first passage. A first oil sump of the motor communicates with a second end of the oil pump through a second passage. When the oil pump is rotating, a port at the first end is an oil outlet of the oil pump, and a port at the second end is an oil inlet of the oil pump. The first end of the oil pump communicates with a second oil sump through a third passage with a first valve. The second end of the oil pump communicates with the second oil sump through a fourth passage with a second valve. In this way, when the oil pump is reversing, coolant may be input into a motor cavity and accumulate in the motor cavity, so as to cool motor components in an immersion manner, thereby improving a cooling effect.