Hybrid Drive Unit Selectable Modes Planetary Gear
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Solution Overview
Problem
Conventional hybrid vehicle drive units have limited selectable modes in electric vehicle mode, restricting torque adjustment and efficiency.
Innovation Solution
A drive unit with a first and second differential mechanism, along with engagement devices, allows for selective connection of rotary elements to increase torque transmission ratios, enabling more operating modes by switching between different torque transmission ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the second planetary gear unit is used as a transmission to transmit torque from the second motor, then the torque can be transmitted to the output member, but the transmission cannot increase or decrease the torque of the second motor, resulting in limited selectable modes in electric vehicle mode
Solution Approach 1:
The transmission system is segmented into two independent planetary gear units (first and second planetary gear units), each capable of independent operation. The first planetary gear unit can operate independently to provide torque multiplication for the second motor, while the second planetary gear unit handles torque transmission. This segmentation allows multiple selectable modes in electric vehicle operation without requiring a single complex variable transmission.
Solution Approach 2:
The first planetary gear unit serves multiple functions: it can operate as a torque amplifier for the second motor during electric vehicle mode, or be engaged/disengaged to create different transmission paths. The engagement devices allow the same hardware configuration to provide multiple operating modes (direct connection, torque multiplication, etc.), increasing versatility without adding complex control systems.
2Adaptability or versatility
If engagement devices are added to connect rotary elements selectively, then more operating modes become available, but the device complexity increases
Solution Approach 1:
The engagement devices are merged with the existing planetary gear unit structures, using the same rotary elements (sun gears, ring gears, carriers) as connection points. The engagement devices connect to these existing elements rather than requiring separate connection mechanisms, thereby adding mode-selectability while minimizing additional structural complexity.
Solution Approach 2:
The engagement devices act as intermediaries that selectively connect or disconnect the first and second planetary gear units. By using these intermediary connection mechanisms, the system can switch between different torque transmission paths and modes without requiring complete redesign of the power flow paths, maintaining structural simplicity while achieving multi-mode operation.
Data Source
AI summary
Provided is a drive unit for a hybrid vehicle which can increase selectable modes in an EV mode. A drive unit includes a first planetary gear unit connected to an engine, and a second planetary gear unit connected to a second rotary element of the first planetary gear unit. The drive unit includes a first engagement device which connects rotary elements of the first planetary gear unit, a third rotary element in the first planetary gear unit, a second engagement device which connects any one of a fifth rotary element and a sixth rotary element in the second planetary gear unit, and a third engagement device which can fix a first rotary element of the first planetary gear unit.