Dual Stator Generator Motor Unit for High Torque Startup
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Solution Overview
Problem
Existing integrated starter generators (ACG starters) face challenges in providing sufficient torque to overcome engine compression at startup while minimizing friction and maintaining efficient power generation, leading to potential degradation in fuel consumption and comfort during vehicle operation.
Innovation Solution
A generator motor unit with a cylindrical rotor and dual stators, where the first stator generates torque through magnetic flux acting on internal magnets and the second stator generates torque through magnetic flux acting on external magnetic bodies, controlled by a switching element group to optimize torque output and reduce friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a large-scale starter is used as the ACG starter to provide sufficient torque at startup, then torque output performance is improved, but friction becomes large during normal travelling and fuel consumption is degraded
Solution Approach 1:
The patent divides the stator into two independent stators: a first stator with external teeth that generates torque during engine starting, and a second stator with internal teeth that generates torque during vehicle acceleration. This segmentation allows each stator to be optimized for its specific function, enabling the system to provide high torque when needed while minimizing friction and energy loss during normal operation.
Solution Approach 2:
The controller dynamically switches between the first stator and the second stator based on operating conditions. During engine starting, the first stator is activated to provide high torque. During normal travelling and acceleration, the second stator is activated to provide assistance with reduced friction. This dynamic switching resolves the contradiction between needing high torque at startup and minimizing energy loss during operation.
2Force
If a large-scale starter is used as the ACG starter to overcome compression at top dead center, then starting capability is improved, but friction increases during normal operation and comfort is degraded
Solution Approach 1:
The patent segments the torque generation function into two independent stators: the first stator handles the high-friction starting operation, while the second stator handles acceleration assistance during normal operation. This segmentation isolates the harmful friction effects to only the necessary starting phase, preventing comfort degradation during normal vehicle operation.
Solution Approach 2:
The controller implements periodic switching between the first and second stators based on operational phases. The first stator is activated periodically during engine starting when high torque is needed, then switches to the second stator for normal operation. This periodic action ensures high starting capability while minimizing friction-related comfort issues during normal travelling.
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 solution enhances torque output performance while limiting friction, resulting in improved acceleration and braking capabilities and efficient power generation.
Implementation Method 1
a first stator having a first plurality of stator cores around which a first set of coils are wound, and that is configured to generate magnetic flux to act on the magnets by energization of the first set of coils, thereby generating torque in the rotor
Implementation Method 2
a second stator having a second plurality of stator cores around which a second set of coils are wound, and that is configured to generate magnetic flux to act on the magnetic bodies by energization of the second set of coils, thereby generating torque in the rotor
Implementation Method 3
to perform energization of the first set of coils of the first stator via the first switching element group so that magnetic flux is generated in the first stator and to stop energization of the second set of coils of the second stator in a state in which the entirety of the second switching element group is brought into an OFF state so that electric power is generated by an action of electromagnetic induction caused by a rotation of the rotor
Data Source
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AI summary
A generator motor unit includes a generator motor including a rotor equipped with magnets, and magnetic bodies that protrude from a wall surface, a first stator that makes magnetic flux act on the magnets, thereby generating torque in the rotor, and a second stator that makes magnetic flux act on the magnetic bodies, thereby generating torque in the rotor; and a controller that controls energization of coils of the first stator and the second stator.