CVT Powertrain Layout With Downstream Clutch for Faster Shifting
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Solution Overview
Problem
Positioning and controlling continuously variable transmissions (CVT) on compact off-road vehicles is challenging due to hardware configuration and varying environments, requiring specific control strategies.
Innovation Solution
A vehicle powertrain assembly with a CVT operably coupled to a prime mover and a clutch positioned downstream of the CVT, allowing for improved packaging, control, and reduced moment of inertia, along with actively controlled clutches for torque limiting and shift-on-the-fly capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the clutch is positioned upstream of the continuously variable transmission (CVT), then the CVT can be compactly packaged, but the moment of inertia increases and shifting speed decreases
Solution Approach 1:
The patent inverts the conventional clutch positioning by placing the clutch downstream of the CVT instead of upstream. This reversal allows the CVT to be compactly packaged while reducing the moment of inertia, thereby improving shifting speed and responsiveness without sacrificing packaging efficiency.
2Manufacturing precision
If electronically controlled clutches are used in the CVT, then precise ratio control is achieved, but the system complexity increases
Solution Approach 1:
The patent replaces traditional mechanical clutch control mechanisms with electronically controlled clutches. This substitution enables precise ratio control through electronic signaling while the control system manages the complexity, providing accurate and responsive transmission ratio adjustments.
3Speed
If the clutch is positioned downstream of the CVT, then the moment of inertia is reduced and acceleration improves, but the control strategy requirements increase
Solution Approach 1:
The patent implements dynamic control strategies that adapt to varying operating conditions. The downstream clutch positioning enables reduced moment of inertia and improved acceleration, while the control system dynamically adjusts clutch engagement and CVT ratio based on real-time vehicle conditions, terrain, and driving demands.
4Adaptability or versatility
If actively controlled clutches are implemented, then torque limiting and shift-on-the-fly capabilities are achieved, but the hardware configuration complexity increases
Solution Approach 1:
The actively controlled clutch system performs multiple functions including torque limiting, shift-on-the-fly capabilities, and protective disengagement. This multi-functional approach consolidates several control features into a single integrated system, managing hardware complexity while providing versatile operational capabilities.
Data Source
AI summary
Aspects of the present disclosure relate to a powertrain assembly including a continuously variable transmission and, in some examples, a clutch. The clutch may be operably coupled between a prime mover and the continuously variable transmission. Additionally, or alternatively, a clutch may be operable coupled after or downstream of the continuously variable transmission. Aspects of the powertrain assembly may be controlled to provide starting-clutch functionality, to provide torque-limiting functionality, and/or to adapt operation of the powertrain for any of a variety of conditions.