Vehicle Transmission Coupling Device Torque Control
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Solution Overview
Problem
The existing step-variable transmission systems with a one-way clutch face challenges in reducing the risk of durability reduction and shifting shock during gear shifts, particularly due to excessive torque loads during resonance and delayed coupling device release, leading to potential tie-up states and shifting shocks.
Innovation Solution
A control apparatus that delays the releasing action of the coupling device by maintaining a predetermined hold-pressure value for the hydraulic pressure, adjusting based on torque requirements, temperature, and vehicle speed, to manage torque loads on the one-way clutch and prevent tie-up states during gear shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the coupling device is released early during shift-up action, then the shifting speed is improved, but the torque load on the one-way clutch becomes excessively large causing durability reduction
Solution Approach 1:
The control device delays the releasing action of the coupling device until after the inertia phase has been initiated. This preliminary timing adjustment ensures that the one-way clutch is already engaged and bearing load before the coupling device releases, preventing excessive torque loads on the one-way clutch while maintaining efficient shifting speed.
2Reliability
If the coupling device is delayed in releasing during shift-up action, then the one-way clutch durability is improved, but the hydraulic pressure becomes excessively high causing tie-up state and shifting shock
Solution Approach 1:
The control device monitors the phase of the shift-up action and uses this feedback to determine the optimal timing for releasing the coupling device. By detecting when the inertia phase has been initiated, the system adjusts the releasing timing to prevent both excessive torque loads and tie-up states, eliminating shifting shocks while protecting the one-way clutch.
3Productivity
If the coupling device is released quickly, then the shifting efficiency is improved, but the risk of one-way clutch durability reduction increases due to resonance torque
Solution Approach 1:
The control device ensures that the one-way clutch is engaged and bearing load before the coupling device releases during the shift-up action. This preliminary engagement prevents resonance torque from causing excessive loads on the one-way clutch, maintaining shifting efficiency while protecting clutch durability.
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 reduces the risk of durability reduction in the one-way clutch and minimizes shifting shocks by optimizing the hydraulic pressure control, ensuring smooth transitions and preventing tie-up states during gear shifts.
Implementation Method 1
a control apparatus that delays the releasing action of the coupling device by maintaining a predetermined hold-pressure value for the hydraulic pressure
Data Source
AI summary
A control apparatus for a vehicle provided with a step-variable transmission including a one-way clutch to be placed in an engaged state to establish a predetermined one of gear positions of the step-variable transmission, and a coupling device disposed parallel with the one-way clutch, includes a control portion configured to control a shift-up action of the step-variable transmission from the above-indicated predetermined one gear position in which the coupling device is placed in its engaged state, the control portion controlling the shift-up action so as to delay a releasing action of the coupling device where a required torque of the vehicle prior to a moment of initiation of an inertia phase of the shift-up action is larger than a predetermined value, with respect to the releasing action where the required torque is not larger than the predetermined value.