Dual Clutch Shift Fork Velocity Control via Hydraulic Feedback
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Solution Overview
Problem
Dual-clutch transmissions (DCTs) face challenges in controlling shift forks during synchronization and engagement/disengagement, leading to inefficiencies, performance reduction, and noise issues due to the on/off power delivery and complex calibration requirements.
Innovation Solution
A control system utilizing a pressure control solenoid and a flow control solenoid, with a piston adjusting the shift fork position, and a fork sensor determining velocity to generate adjusted commands, ensuring smooth engagement and disengagement by ramping pressure and flow commands based on fork position and velocity profiles, reducing calibration time and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional hydraulic control is used for shift forks, then the system structure is simple, but the shift quality is poor and banging noise occurs during engagement
Solution Approach 1:
The patent implements dynamic control of shift fork velocity through a velocity determining module that continuously adjusts the hydraulic flow command based on real-time fork position feedback from a sensor. This dynamic adjustment ensures the fork moves at optimal speeds during engagement, preventing banging noise while maintaining smooth synchronization. The system transitions from static hydraulic control to dynamic closed-loop control, adapting parameters in real-time during the shifting process.
Solution Approach 2:
The patent incorporates a fork position sensor that provides continuous feedback to the velocity determining module. This feedback loop allows the system to monitor the actual fork position and adjust the hydraulic flow command accordingly, ensuring precise control during engagement. The feedback mechanism enables the system to detect when the fork is within a predetermined distance of the target position and modify the velocity profile to prevent impact and reduce noise.
2Object-affected harmful factors
If complex calibration procedures are implemented to improve shift quality, then shift performance improves, but calibration time and effort increase significantly
Solution Approach 1:
The patent implements a self-calibrating system where the velocity determining module automatically adjusts hydraulic flow commands based on real-time feedback from the fork position sensor during normal operation. The system performs adaptive calibration without requiring external intervention or lengthy manual procedures. The control module continuously learns and optimizes the velocity profile based on actual shifting conditions, eliminating the need for extensive pre-calibration while maintaining high shift quality.
Solution Approach 2:
The patent incorporates preliminary velocity profiling that is pre-programmed into the velocity determining module based on optimal shifting characteristics. This preliminary action provides a baseline velocity profile that is automatically adjusted during operation, combining pre-planned optimization with real-time adaptation. The system starts with predetermined velocity curves that have been optimized for smooth engagement, reducing the need for subsequent calibration adjustments.
3Ease of operation
If manual clutch operation is used, then the driver has full control over power flow, but power delivery becomes intermittent and efficiency is reduced
Solution Approach 1:
The patent replaces the mechanical clutch operation system with an automated hydraulic control system that uses electronic sensors and control modules to manage power flow. The manual mechanical linkage and clutch pedal are substituted with automated fork actuators controlled by hydraulic solenoids and electronic control units. This substitution eliminates the need for driver intervention while maintaining precise control over power delivery, ensuring continuous engagement and improving efficiency without sacrificing operational control.
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 achieves smoother power delivery, reduces noise, and minimizes calibration efforts by precisely controlling shift fork velocity and position, enhancing the efficiency and performance of DCTs.
Implementation Method 1
A pressure control solenoid and a flow control solenoid may be used to control a position of a shift fork
Implementation Method 2
A pressure control solenoid and a flow control solenoid having an input in fluid communication with the pressure control solenoid
Data Source
AI summary
A control system includes a pressure control solenoid and a flow control solenoid having an input in fluid communication with the pressure control solenoid. A piston adjusts a position of a shift fork and includes a first area in fluid communication with the pressure control solenoid and a second area in fluid communication with the flow control solenoid. A fork sensor senses a position of a shift fork. A flow determining module determines a fork velocity for the shift fork, adjusts the fork velocity to generate an adjusted fork velocity based on the position, and generates a flow command for the flow control solenoid based on the adjusted fork velocity. A pressure determining module generates a pressure command for the pressure control solenoid. The shift fork is at least one of moved from a sync position to an engaged position and from an engaged position to a neutral position.