Torque Transmitter Engagement Control via Variable Bleed Solenoid
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional torque transmitting mechanism engagement methods in automatically shiftable transmissions experience pressure variations and control system instability during the trim phase, leading to poor shift quality due to fluid leakage and pressure fluctuations.
Innovation Solution
An electro-hydraulic control system utilizing a variable bleed solenoid valve to provide pressurized fluid at specific pressure levels for predetermined times, including a maximum pressure for filling, a minimum pressure for stabilization, and an intermediate pressure for trimming the torque transmitting mechanism, thereby stabilizing the fluid pressure and reducing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If maximum pressure is applied to fill the torque transmitting mechanism quickly, then fill time is reduced, but pressure variations and instability occur during the trim phase
Solution Approach 1:
The patent segments the pressure application process into three distinct phases: fill phase (maximum pressure), intermediate phase (reduced pressure), and trim phase (moderate pressure). This segmentation allows each phase to be optimized independently, reducing pressure variations during the trim phase while maintaining quick fill capability.
Solution Approach 2:
The patent implements dynamic pressure adjustment by varying the solenoid valve duty cycle across different phases of torque transmitting mechanism engagement. The duty cycle is adjusted from high during fill phase to lower during intermediate and trim phases, enabling adaptive pressure control that maintains stability while achieving quick engagement.
2Speed
If high pressure is maintained throughout engagement, then engagement speed is improved, but fluid leakage increases
Solution Approach 1:
The patent employs periodic pressure application with distinct high-pressure and low-pressure intervals. Maximum pressure is applied only during the initial fill phase, followed by reduced pressure during intermediate and trim phases. This periodic action pattern achieves rapid engagement while minimizing fluid leakage during sustained pressure periods.
3Loss of substance
If pressure is reduced during trim phase to reduce leakage, then fluid loss decreases, but engagement smoothness may be compromised
Solution Approach 1:
The patent applies preliminary action by fully filling the torque transmitting mechanism with pressurized fluid during the fill phase before reducing pressure. This preliminary filling ensures that the mechanism is completely charged, and subsequent pressure reduction during trim phase occurs on a fully filled system, maintaining smooth engagement while reducing leakage.
Solution Approach 2:
The patent changes the pressure parameter dynamically during the engagement process. By transitioning from maximum pressure during fill to reduced pressure during trim phase, the system optimizes both leakage reduction and engagement smoothness through parameter variation rather than maintaining constant pressure.
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
This approach stabilizes the fluid pressure and reduces leakage, resulting in smooth and precise engagement of the torque transmitting mechanism, enhancing shift quality without increasing pump capacity or efficiency costs.
Implementation Method 1
provide the pressurized fluid at a high pressure level to the torque transmitting mechanism
Implementation Method 2
stabilizes the fluid pressure and reduces leakage
Data Source
AI summary
A control system operable to engage a torque transmitting mechanism, the control system having at least one variable bleed solenoid valve operable to selectively provide pressurized fluid to selectively engage at least one torque transmitting mechanism. An electronic control unit is also provided to provide control to the at least one variable bleed solenoid valve. The electronic control unit commands the variable bleed solenoid valve to provide the pressurized fluid to the at least one torque transmitting mechanism for a first predetermined time and to subsequently substantially disallow the pressurized fluid to the at least one torque transmitting mechanism for a second predetermined time subsequent to the first predetermined time. The electronic control unit subsequently commands an intermediate pressure level to trim the torque transmitting mechanism into engagement. A method for providing engagement to the torque transmitting mechanism is also provided.