Dual Clutch Transmission Gear Preselection Control
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Solution Overview
Problem
Dual clutch transmissions experience undesirable noise emissions due to vibrational excitation, particularly when preselecting the target gear, which impairs driving comfort, especially with diesel engines.
Innovation Solution
Preventing or reversing the selection of the target gear based on specific parameters such as torque or speed limits to avoid gear rattle by decoupling the vibration system, ensuring that the preselection only occurs when the torque or speed is within predetermined limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the target gear is preselected in a dual clutch transmission, then the gear change time is reduced and driving comfort is improved, but noise emissions increase due to vibrational excitation of the drive
Solution Approach 1:
The control unit monitors drive parameters (torque, speed, acceleration) and dynamically adjusts the gear preselection behavior based on these parameters. When torque exceeds a threshold value, the preselection of target gear is prevented or reversed, thereby changing the operational parameters of the transmission system to avoid the harmful vibration excitation while maintaining efficient operation under normal conditions
Solution Approach 2:
Instead of always preselecting the target gear to minimize shift time, the system inverts the logic by preventing or reversing the preselection when specific conditions (high torque) are detected. This conditional reversal of the preselection action eliminates the gear rattle and noise emissions that would otherwise occur during high-torque operations
2Speed
If the target gear is preselected, then shifting speed is improved, but gear rattle occurs due to vibrational excitation transmitted through the engaged gear
Solution Approach 1:
The system changes the operational state of the transmission by preventing target gear preselection when torque or speed parameters exceed predetermined thresholds. This parameter-based control dynamically adjusts whether preselection occurs, eliminating gear rattle during high-torque conditions while maintaining fast shifting during normal operation
Solution Approach 2:
The control unit continuously monitors drive parameters (torque, speed, acceleration) and uses this feedback to determine whether target gear preselection should be permitted. When feedback indicates high torque conditions that would cause gear rattle, the control unit prevents or reverses the preselection action, thereby eliminating the harmful vibration while maintaining efficient shifting under normal conditions
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
Significantly reduces noise emissions by preventing gear rattle through controlled preselection of the target gear, enhancing driving comfort and reducing vibration transmission to the input shaft.
Implementation Method 1
The first clutch allows the first input shaft to be connected to a drive such as an internal combustion engine in a motor vehicle, while the second clutch enables torque to be transmitted from the drive to the second input shaft
Implementation Method 2
undesirable noise emissions that can be attributed to vibrational excitation of the drive. In particular, when a diesel engine is used as the drive, noise emissions can occur in certain driving situations
Implementation Method 3
undesirable noise emissions in the form of gear rattle can be attributed to the preselected target gear
Data Source
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AI summary
The method involves connecting input shafts with a drive by respective clutches, and connecting the input shafts with an output by gears for torque transmission from the drive to the output. A pre-selection of a target gear is controlled before changing one of the gears from a source gear to the target gear. The pre-selection of the target gear is prevented depending on parameters e.g. operating parameters, of the drive and/or a double clutch transmission. An independent claim is also included for a controller of a double clutch transmission comprising a clutch.