Lockup Clutch Hydraulic Pressure Control for Shock Suppression
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Solution Overview
Problem
Existing lockup clutch control systems face challenges in preventing shock during complete engagement when zero-slip state is not achieved, despite performing zero-slip control, due to varying vehicle conditions.
Innovation Solution
The control system employs a fluid coupling with a lockup clutch and an electronic control unit that executes zero-slip control, followed by a sweep increase in hydraulic pressure at a reduced rate if zero-slip control is not established within a predetermined time, ensuring the hydraulic pressure reaches or exceeds the level achieved when zero-slip control is successful, thereby minimizing shock during complete engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If zero-slip control is performed to minimize hydraulic pressure, then hydraulic pressure is reduced, but shock may occur if zero-slip state is not achieved within predetermined time
Solution Approach 1:
The patent applies dynamics by making the hydraulic pressure increase rate variable based on control convergence status. When zero-slip control converges within predetermined time, a normal increase rate is used; when it does not converge, a reduced increase rate is applied. This dynamic adjustment of the pressure increase rate prevents shock while maintaining low hydraulic pressure when conditions permit.
Solution Approach 2:
The patent changes the parameter of hydraulic pressure increase rate based on the convergence status of zero-slip control. By monitoring whether the control converges within a predetermined time period, the system adjusts the pressure increase rate parameter accordingly - using a normal rate for converged cases and a reduced rate for non-converged cases, thereby preventing shock without sacrificing pressure reduction benefits.
2Productivity
If transition is performed to complete engagement quickly, then productivity is improved, but shock occurs when zero-slip state is not established
Solution Approach 1:
The patent makes the engagement process dynamic by adjusting the hydraulic pressure increase rate based on real-time feedback from zero-slip control convergence status. When convergence occurs quickly, the system maintains high productivity with normal pressure increase rates. When convergence is delayed, the system automatically reduces the pressure increase rate to prevent shock, thus adapting engagement speed to actual system conditions.
Solution Approach 2:
The patent implements feedback control by monitoring whether zero-slip control converges within a predetermined time period and using this information to adjust the hydraulic pressure increase rate. This feedback mechanism ensures that the engagement process adapts to actual system behavior, maintaining high productivity when conditions allow while preventing shock when convergence is delayed.
3Adaptability or versatility
If zero-slip control is performed under varying vehicle conditions, then adaptability is improved, but reliability of achieving zero-slip state decreases
Solution Approach 1:
The patent enhances adaptability by dynamically adjusting the hydraulic pressure increase rate based on zero-slip control convergence status under varying vehicle conditions. This dynamic approach allows the system to maintain reliable operation across different conditions by adapting the pressure increase strategy - using normal rates when convergence is achieved and reduced rates when it is not, thereby preventing shock in all scenarios.
Solution Approach 2:
The patent changes the hydraulic pressure increase rate parameter based on convergence status to maintain reliability across varying vehicle conditions. By monitoring whether zero-slip control converges within the predetermined time period and adjusting the pressure increase rate accordingly, the system ensures reliable shock prevention regardless of whether zero-slip state is achieved, thus maintaining operational reliability under diverse 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
This approach effectively suppresses the occurrence of shock during complete engagement even when zero-slip state is not achieved, by gradually increasing hydraulic pressure to the complete engagement target, ensuring smooth transition.
Implementation Method 1
a fluid coupling (a commonly called 'torque converter' which increases torque input from an input side and transmits torque to an output side is an example of a fluid coupling)
Implementation Method 2
sweep-increase a lockup clutch hydraulic pressure to a predetermined hydraulic pressure and then increase the lockup clutch hydraulic pressure to a complete engagement target hydraulic pressure
Data Source
AI summary
In a transmission with a lockup clutch, in a case where zero-slip control of the lockup clutch is not established (converged) within a predetermined time, a sweep increase of a lockup clutch hydraulic pressure starts at an increase rate smaller than a normal increase rate in a case where the zero-slip control is established within the predetermined time, the increase rate until the end of the sweep increase is set to be equal to or less than the normal increase rate, and in addition, a hydraulic pressure at the time of the end of the sweep increase is set to be equal to or greater than a hydraulic pressure in a case where the zero-slip control is established within the predetermined time. With such control, in a case where the zero-slip state is not brought, suppressing the occurrence of shock when complete engagement is carried out.