Rotor-Stator Gap Oil Injection for Controlled Motor Braking
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Solution Overview
Problem
Existing vehicle systems lack efficient methods for controlled introduction of oil into the rotor-stator gap of electric machines to achieve braking, battery heating, and cabin heating, while also effectively managing heat transfer for various vehicle systems.
Innovation Solution
A vehicle system is configured with a conduit to direct oil into the rotor-stator gap, utilizing a flow control device to manage oil flow, and a heat exchanger to transfer heat to coolant systems for battery and cabin heating, with a controller regulating oil flow and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If oil is introduced into the rotor-stator gap for braking, then braking capability is improved, but control precision deteriorates due to lack of existing flow control mechanisms
Solution Approach 1:
The patent applies parameter changes by introducing a flow control device that can dynamically adjust oil flow rate parameters. This allows precise control of the amount of oil introduced into the rotor-stator gap, enabling modulation of braking force intensity. The flow control device transforms the binary on/off oil introduction into a continuously controllable parameter, resolving the contradiction between achieving sufficient braking force and maintaining precise braking control.
2Temperature
If oil flow rate is increased for faster heating, then heating efficiency is improved, but energy loss increases due to excessive oil circulation
Solution Approach 1:
The patent applies partial action by using the flow control device to introduce only the necessary amount of oil into the rotor-stator gap for effective heating, rather than excessive oil circulation. The system controls oil flow to match the actual heating demand, preventing energy waste from circulating more oil than needed. This resolves the contradiction by achieving fast heating through targeted oil introduction while minimizing energy loss through precise flow management.
3Device complexity
If mechanical valve is used for oil flow control, then device complexity is reduced, but control flexibility deteriorates due to fixed threshold operation
Solution Approach 1:
The patent applies multi-functionality by designing a flow control device that can operate in multiple modes: it responds to rotor speed thresholds like a mechanical valve but also accepts external control signals for adaptive flow regulation. This universal control mechanism can function as both a simple mechanical threshold trigger and a flexible electronically-controlled flow regulator, resolving the contradiction between simplicity and adaptability by combining both capabilities in one device.
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 provides controlled braking and heating capabilities by managing oil flow and heat transfer efficiently, enhancing vehicle performance and comfort.
Implementation Method 1
Friction between the oil and the rotor warms the oil
Implementation Method 2
a heat exchanger configured to exchange heat between the oil and a coolant of a temperature management system
Data Source
AI summary
A vehicle system including: an electric machine configured for incorporation into a powertrain of a vehicle, the electric machine including a rotor, a stator, and a gap defined between the rotor and the stator; a conduit configured to direct oil into the gap; and a flow control device configured to control flow of the oil through the conduit into the gap. Friction between the oil and the rotor warms the oil and slows rotation of the rotor to brake the vehicle when the electric machine is connected to the powertrain.