eCVT Drive System Non-Friction Coupling Assemblies
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Solution Overview
Problem
Current hybrid vehicle powertrains and automatic manual transmissions experience undesirable shift shocks and efficiency losses due to torque interruptions during gear changes, leading to unpleasant driving experiences and reduced mechanical efficiency.
Innovation Solution
A drive system with a transmission that incorporates non-friction, controllable coupling assemblies and a gear set with multiple operating modes, including EV, hybrid, and ICE modes, utilizing three-position linear actuators and clutches to manage power flow without hydraulic control, allowing for efficient and smooth power distribution across different driving conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydraulic clutches are used for gear changes, then gear shifting can be achieved, but torque interruptions and shift shocks occur reducing efficiency and comfort
Solution Approach 1:
The patent replaces the hydraulic clutch system with an electric motor system. The electric motor directly controls the connection between transmission elements, eliminating the need for hydraulic actuators. This substitution allows for precise control of torque transmission during gear changes, preventing torque interruptions while maintaining gear shifting capability, thereby resolving the contradiction between productivity and energy loss.
Solution Approach 2:
The patent introduces an electric motor as an intermediary device between the transmission input and output shafts. This electric motor acts as a mediator that can independently control torque flow during gear transitions, smoothing out torque interruptions that would otherwise occur during clutch engagement. The intermediary electric motor enables continuous torque transmission while effecting gear changes, eliminating shift shocks and efficiency losses.
2Productivity
If multiple clutches are engaged simultaneously during gear changes, then gear shifting is achieved, but shift shocks occur reducing driving comfort
Solution Approach 1:
The patent employs dynamic control of the electric motor during gear transitions. The motor speed and torque are continuously adjusted based on real-time transmission state, enabling smooth and progressive engagement of gear elements. This dynamic control prevents simultaneous engagement of multiple clutches, eliminating shift shocks while maintaining efficient gear shifting capability.
Solution Approach 2:
The patent implements preliminary engagement of the electric motor before actual gear switching occurs. The motor is pre-positioned and pre-loaded to prepare for the upcoming gear transition, ensuring that torque transmission is already established before the clutch engagement begins. This preliminary action prevents torque interruptions and shift shocks by maintaining continuous power flow throughout the gear change process.
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 improved transmission efficiency and smooth power delivery across various modes, reducing shift shocks and enhancing driving experience by enabling efficient power management between electric and internal combustion power sources.
Implementation Method 1
via a magnetic field produced by a stator
Implementation Method 2
The linear motor or actuator moves which, in turn, moves plungers coupled to struts
Implementation Method 3
The actuator has a ring of permanent magnets that latches the clutch into two states, ON and OFF
Data Source
AI summary
A drive system having eCVT functionality with AMT cost advantages includes a transmission having a plurality of different operating modes. The system includes a transmission output shaft, a stationary member and a gear set including first, second, and third elements. The first element connects with the transmission output shaft. An output shaft of a non-electric power plant connects with the first element through the second element for driving the first element. A drive shaft of an electric power plant connects with the first element through the third element for driving the first element. The system includes a plurality of non-friction, controllable, coupling assemblies. A first coupling assembly has a first coupling state for grounding the second element to the stationary member, a second coupling state for grounding the third element to the stationary member and an uncoupling state to allow the second and third elements to drive the first element.