Transmission Clutch Control for Continuous Power Shift Torque Transfer
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Solution Overview
Problem
Existing vehicle transmission systems face challenges in maintaining a smooth and continuous power flow during gear shifts, particularly in off-highway vehicles, leading to potential disruptions in torque flow and vehicle performance.
Innovation Solution
A method involving a transmission controller that utilizes a first and second clutching device, where the state of the second clutching device is controlled by changing the state of the first clutching device, including engagement pressure and speed control, to facilitate smoother and more efficient shifting by determining torque transmission directions and using feedback and feedforward control procedures to synchronize torque transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional gear shifting is used in vehicle transmissions, then the transmission can change gears, but the power flow becomes disrupted and torque transmission is interrupted
Solution Approach 1:
The patent implements continuous power flow during gear shifts by maintaining torque transmission through the clutching devices throughout the entire shifting process. The first clutching device remains engaged while the second clutching device is being engaged, ensuring that torque continues to be transmitted from the input shaft to the output shaft without interruption. This eliminates the traditional interruption in power flow that occurs during gear changes.
Solution Approach 2:
The patent prepares the second clutching device for engagement before the first clutching device is disengaged. The control system pre-charges the second clutching device and synchronizes its speed with the input shaft, so that when the first clutching device is released, the second clutching device is already ready to take over torque transmission immediately, maintaining continuous power flow.
2Power
If engagement pressure is increased to improve torque transfer, then torque transmission becomes more efficient, but the clutching device experiences higher stress and wear
Solution Approach 1:
The patent divides the torque transmission function into two separate clutching devices that operate at different stages of the shifting process. The first clutching device handles torque transmission during the initial phase, while the second clutching device takes over as it is being engaged. This segmentation allows each clutching device to operate at optimal engagement pressures for shorter durations, reducing cumulative stress and wear on individual components.
Solution Approach 2:
The patent dynamically adjusts the engagement pressure of both clutching devices during the shifting process. The control system modulates the engagement pressure of the first clutching device as the second clutching device is being engaged, reducing the load on the first device gradually. This dynamic pressure adjustment optimizes torque transfer efficiency while minimizing peak stresses on the clutching components.
Data Source
AI summary
A method of shifting a vehicle transmission including a first clutching device and a second clutching device is described. At least a portion of the first clutching device is coupled with or configured to be coupled with at least a portion of the second clutching device. The method may include the steps of engaging the second clutching device, where engaging the second clutching device includes controlling a state of the second clutching device by changing a state of the first clutching device. A transmission controller and a vehicle driveline are also described.