Closed Coolant Circuit for EV Drive Cooling and Lubrication
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Solution Overview
Problem
Existing cooling and lubrication systems for electric vehicle components, particularly electric machines, face inefficiencies due to waste heat limitations, leading to reduced power output and increased wear, as they struggle to effectively manage heat dissipation and lubrication within vehicle housings.
Innovation Solution
A closed coolant circuit system within the vehicle housing, comprising a coolant sump, two pumps, and a heat exchanger, which delivers and recirculates a coolant (such as oil or water) to components for both cooling and lubrication, ensuring efficient heat absorption and distribution while minimizing coolant loss and wear, with integrated components like a coolant reservoir and spray nozzles for targeted cooling and lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional cooling system is used for the electric machine, then the electric machine can be operated, but waste heat limits the power output and causes the control unit to reduce power when exceeding limiting temperature
Solution Approach 1:
The patent extracts the cooling function from the lubrication system by introducing a separate coolant circulation system with dedicated coolant outlets that spray coolant directly onto the electric machine components. This separation allows independent optimization of cooling performance without interfering with the lubrication function, enabling higher power output by effectively managing heat dissipation.
Solution Approach 2:
The patent introduces coolant as an intermediary substance to transfer heat away from the electric machine. The coolant circulates through a dedicated system with pumps and heat exchangers, acting as a mediator between the heat-generating electric machine components and the external environment, thereby enabling sustained high-power operation.
2Temperature
If coolant is sprayed onto components for cooling, then heat dissipation is improved, but coolant loss increases and requires a closed circuit system
Solution Approach 1:
The patent implements a closed coolant circuit system where coolant that has performed its cooling function is collected from the housing, pumped back through the heat exchanger, and reused. This recovery and recycling approach eliminates coolant loss, allowing continuous cooling operation without requiring additional coolant replenishment.
3Temperature
If a closed coolant circuit system with multiple pumps and heat exchanger is implemented, then cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The patent designs the coolant system to serve multiple functions: the coolant circulation system cools both the electric machine and the transmission components, while also providing lubrication where needed. The housing serves as both a structural enclosure and a coolant collection reservoir. This multi-functionality reduces the need for separate dedicated systems, thereby managing complexity while maintaining high cooling efficiency.
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 system enhances the efficiency of electric machine operation by maintaining optimal temperatures, reducing wear, and improving the overall drive train efficiency through effective heat dissipation and lubrication, while simplifying installation with integrated components.
Implementation Method 1
a heat exchanger, which is configured for cooling the coolant delivered by the second coolant pump
Implementation Method 2
The coolant is provided, on the one hand, for absorbing and dissipating heat
Implementation Method 3
The coolant line system routes the coolant to the coolant outlets at least via the heat exchanger
Implementation Method 4
The coolant is provided, on the one hand, for absorbing and dissipating heat and, on the other hand, for lubricating parts and/or components, so that the parts and/or components can interact with low wear
Data Source
AI summary
A device (1) for cooling and lubricating components of a vehicle (2) includes at least one housing (3), a coolant sump (4), a first coolant pump (5.1) configured for delivering coolant (6) from a first housing section (A) for accommodating a transmission (12) into the coolant sump (4), a second coolant pump (5.2) configured for delivering coolant (6) from the coolant sump (4) into a coolant line system (8), and a heat exchanger (7) configured for cooling the coolant (6) delivered by the second coolant pump (5.2). The coolant line system (8) fluidically connects at least the second coolant pump (5.2) to the heat exchanger (7) and, at least indirectly, fluidically connects the heat exchanger (7) to multiple coolant outlets (11.1, 11.2, 11.3, 11.4, 11.5) for spraying coolant (6) onto components in the housing (3) that require cooling and lubrication.