Power Transmission Control Device Temperature-Based Pressure Management
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Solution Overview
Problem
When a pressure accumulator is used for both engaging mechanism engagement during idling stop and parking lock mechanism movement, the accumulated pressure is insufficient at high temperatures due to fluid viscosity changes, leading to wasted pressure at low temperatures, and inefficient pressure utilization.
Innovation Solution
A power transmission control device that includes a temperature detecting unit to set a permission time for pressure accumulation based on fluid temperature, ensuring sufficient pressure for parking lock at low temperatures and preventing unnecessary pressure accumulation at high temperatures, with a mechanism to prohibit pressure use for engagement at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure accumulator accumulates sufficient pressure for parking lock at low temperatures, then parking lock reliability is improved, but pressure wastage occurs at high temperatures
Solution Approach 1:
The control device dynamically adjusts the permission time for pressure accumulator discharge based on detected working fluid temperature. At low temperatures, a longer permission time allows sufficient pressure accumulation for reliable parking lock. At high temperatures, a shorter permission time prevents excessive pressure accumulation that would be wasted. This dynamic adaptation resolves the contradiction between ensuring parking lock reliability and preventing pressure wastage.
Solution Approach 2:
The system changes the operational parameter (permission time) based on temperature conditions. The storage unit stores multiple permission time values corresponding to different temperature ranges, and the receiver unit selects the appropriate permission time based on current temperature. This parameter change strategy allows the system to optimize pressure accumulation for each temperature condition, ensuring reliability when needed and preventing wastage when not needed.
2Reliability
If the pressure accumulator supplies working fluid to the engaging mechanism during idling stop restart, then engagement reliability is improved, but pressure becomes insufficient for parking lock at high temperatures
Solution Approach 1:
The system dynamically controls the duration of pressure supply to the engaging mechanism based on temperature. At high temperatures, the permission time is shortened, allowing less pressure to be consumed by the engaging mechanism, thereby preserving sufficient pressure for the parking lock. At low temperatures, a longer permission time allows full pressure utilization for engagement. This dynamic control resolves the contradiction between ensuring engagement reliability and maintaining sufficient pressure for parking lock.
3Device complexity
If a fixed permission time is used for pressure accumulation, then control simplicity is maintained, but temperature-dependent pressure optimization is lost
Solution Approach 1:
The control device transitions from a fixed permission time approach to a dynamic, temperature-dependent permission time approach. The temperature detecting unit continuously monitors working fluid temperature, and the receiver unit adjusts the permission time accordingly. This dynamic approach maintains control simplicity through automated temperature-based decision logic while significantly improving pressure utilization reliability across varying temperature conditions.
Solution Approach 2:
The system implements feedback control by continuously detecting working fluid temperature and using this information to adjust the permission time for pressure accumulation. The temperature detection creates a feedback loop that allows the system to automatically adapt to changing thermal conditions, ensuring optimal pressure management without requiring complex manual intervention or predetermined fixed settings.
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 solution ensures appropriate pressure accumulation for parking lock across temperature variations, reducing pressure wastage and maintaining sufficient pressure for engaging mechanisms, while preventing unnecessary pressure use at high temperatures.
Implementation Method 1
a pressure accumulator configured to accumulate a pressure in the working fluid
Implementation Method 2
a temperature detecting unit configured to detect a temperature of the working fluid
Implementation Method 3
An amount of working fluid such as working oil or the like leaking from a gap in a valve varies as viscosity or the like varies according to a temperature thereof
Data Source
AI summary
A power transmission includes a first brake, a pressure regulating valve, an accumulator, an oil temperature sensor, a second electromagnetic valve allowing supply of working oil to a piston, and a power transmission control device. The power transmission control device includes a memory relating and storing a working oil temperature and a permission time configured to allow release of the accumulator, and a receiver unit receiving a starting request. The accumulator is connected such that the working oil, in which the pressure is accumulated, can be supplied to the first brake and the piston. The power transmission control device sets a permission time corresponding to a temperature of the working oil on the basis of the memory. The working oil, in which the pressure is accumulated, is supplied to the first brake only during the permission time when restart information is received, while a vehicle performs idling stop control.