CVT Driveline Torque Adjustment for Fuel Efficiency
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Solution Overview
Problem
Automotive driveline systems face a trade-off between fuel efficiency and performance, where improving one often compromises the other, and existing solutions require costly redesigns and new vehicle purchases to implement design changes.
Innovation Solution
A system incorporating a continuously variable transmission (CVT) coupled between an input source and a step-variable transmission, allowing for adjustable torque output through a slip-limiting device and variator, enabling efficient operation across a range of engine speeds and torque levels without the need for extensive redesign.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If engine design is redesigned to improve fuel efficiency and reduce emissions, then fuel efficiency is improved, but performance is sacrificed and manufacturing cost increases
Solution Approach 1:
The patent applies dynamics by implementing a continuously variable transmission (CVT) that allows the engine to operate at optimal speeds for fuel efficiency while dynamically adjusting the transmission ratio to maintain performance across different driving conditions. The CVT enables the engine to remain in its efficient operating range regardless of vehicle speed or load requirements.
Solution Approach 2:
The patent utilizes parameter changes by varying the transmission ratio continuously through the CVT mechanism. This allows the system to change the relationship between engine speed and vehicle speed, enabling the engine to operate at parameters that optimize fuel efficiency while still delivering required performance output.
2Use of energy by moving object
If engine design is redesigned to improve fuel efficiency and reduce emissions, then fuel efficiency is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies universality by using a CVT that can serve multiple functions: improving fuel efficiency, maintaining performance, and working with existing engine designs. This multi-functional approach allows the same transmission system to address multiple concerns without requiring separate redesigns for each objective.
Solution Approach 2:
The patent introduces the CVT as an intermediary component between the engine and the drivetrain. This mediator allows the existing engine design to be preserved while the CVT handles the optimization of fuel efficiency and performance, avoiding the need to redesign the entire powertrain system.
3Use of energy by moving object
If CVT transmission ratio is adjusted continuously, then fuel efficiency is improved, but system complexity increases
Solution Approach 1:
The patent applies mechanics substitution by replacing traditional multi-gear mechanical transmissions with a CVT system that uses variable diameter pulleys and a belt. This substitution enables continuous ratio adjustment through mechanical means rather than discrete gear shifts, simplifying the control mechanism while maintaining continuous variability.
Data Source
AI summary
Systems and methods for operating a driveline system are disclosed and include a step-variable transmission. A continuously variable transmission (CVT) is coupled between an input source and the step-variable transmission. The CVT receives a first torque from the input source and outputs a second torque. The CVT has a plurality of planetary members in rolling contact with an inner race and an outer race. A radial distance between the planetary members and a drive-transmitting member corresponds to a transmission ratio of the CVT.