Hybrid Powertrain Efficiency via Dynamic Transmission Ratio
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Solution Overview
Problem
Hybrid powertrain systems using two motor generators face efficiency degradation as the transmission ratio decreases, particularly in power-split hybrid vehicles, leading to reduced fuel efficiency and acceleration performance.
Innovation Solution
A hybrid powertrain apparatus is designed with a first and second planetary gear device, including at least three rotary elements, motors, brakes, and a clutch to variably connect the engine and motors, allowing for optimal positioning and operation in different modes, such as electric vehicle and hybrid modes, using a speed multiplication or reduction gear to enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a power-split hybrid structure with two motor generators is used, then fuel efficiency can be improved through engine on/off control and regenerative braking, but efficiency degrades significantly when transmission ratio decreases below the mechanical point
Solution Approach 1:
The patent introduces a dynamic transmission ratio adjustment mechanism that allows the powertrain to operate at optimal efficiency points across different driving conditions. The system dynamically changes the transmission ratio to maintain the motor generator operating point near the mechanical point, preventing efficiency degradation when transmission ratio decreases.
Solution Approach 2:
The patent changes the transmission ratio parameter dynamically based on driving conditions to maintain optimal powertrain efficiency. By adjusting the transmission ratio to keep the motor generator operating near its mechanical point, the system prevents the radical efficiency decrease that occurs when transmission ratio drops below this point.
2Adaptability or versatility
If a compound split structure with two motor generators connected to different rotary elements is used, then operational flexibility is improved, but device complexity increases
Solution Approach 1:
The patent implements a multi-functional powertrain system where the same compound split structure supports multiple operating modes including hybrid mode, electric vehicle mode, and two-motor mode. This universal design achieves operational flexibility without requiring separate systems for different functions.
Solution Approach 2:
The patent segments the powertrain into distinct functional modules (engine, two motor generators, planetary gear device, brakes, clutch) that can operate independently or in combination. This modular segmentation provides operational flexibility while managing complexity through clear functional separation.
3Use of energy by moving object
If traditional hybrid mode and electric vehicle mode are implemented, then fuel efficiency is improved, but acceleration performance is limited
Solution Approach 1:
The patent enables continuous power delivery across all operating modes by allowing both motor generators to operate simultaneously in the two-motor mode. This continuous action of both motors provides superior acceleration performance while maintaining the ability to switch to fuel-efficient hybrid or electric vehicle modes when acceleration is not required.
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 apparatus achieves high fuel efficiency and acceleration performance by optimizing the arrangement and connection of engines and motors, enabling efficient operation across various modes with minimal elements, thereby increasing fuel efficiency and acceleration.
Implementation Method 1
a first planetary gear device including at least three rotary elements
Implementation Method 2
a first brake provided to vary a rotation restricting state of the first rotary element
Implementation Method 3
a clutch configured to variably connect the first rotary element and the engine so as to vary a mutual rotation restricting state
Data Source
AI summary
A hybrid powertrain apparatus comprising a first planetary gear device including at least three rotary elements, a first motor, an output axis, and a second motor connected to a first rotary element, a second rotary element, and a third rotary element of the first planetary gear device; a first brake and a second brake provided to vary rotation restricting states of the first rotary element and the third rotary element relative to a fixing member; an engine variably connected to the first rotary element; a clutch configured to variably connect the first rotary element and the engine to vary a mutual rotation restricting state between the first rotary element and the engine; and a speed multiplication gear or a speed reduction gear between the clutch and the engine and connecting the clutch and the engine.