CVT Control Apparatus Hydraulic Pressure Management During Abnormality
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Solution Overview
Problem
In continuously variable transmissions, errors can hinder the calculation of a target shifting ratio, leading to potential sudden deceleration and compromising user safety and convenience, as existing solutions either prevent shifting operations or fail to manage hydraulic pressures effectively during abnormalities.
Innovation Solution
A control apparatus that includes a shifting controller and a detector to adjust hydraulic pressure within a specific range, ensuring minimal operational availability while maintaining shifting functionality and preventing sudden deceleration, by setting a target shifting ratio based on vehicle driving information and detecting abnormalities to adjust line pressure accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic pressure is minimized to avoid sudden downshift when actuator error occurs, then sudden deceleration is avoided, but shifting operation becomes unavailable
Solution Approach 1:
The patent changes the hydraulic pressure parameter from minimal (avoiding sudden downshift) to a moderate range (first value to second value) that enables shifting operations while still preventing sudden deceleration. The controller adjusts the target shifting ratio based on detected abnormalities, allowing the system to operate in a modified but functional state rather than completely disabling shifting.
2Reliability
If shifting control is performed to prevent sudden deceleration during abnormality, then user safety is improved, but shifting ratio control precision deteriorates
Solution Approach 1:
The patent applies partial action by maintaining shifting ratio control within acceptable bounds rather than achieving precise target ratios. When abnormality is detected, the controller adjusts the target shifting ratio to be within a range that prevents sudden deceleration, accepting that the ratio may not precisely match the original target but is sufficient for safe operation.
3Reliability
If hydraulic pressure is controlled within a specific range during abnormality, then sudden deceleration is avoided and shifting operation is maintained, but system complexity increases
Solution Approach 1:
The patent implements feedback by having the detector continuously monitor for abnormalities and the controller continuously adjust the target shifting ratio based on the detected state. This closed-loop feedback mechanism automatically responds to abnormal conditions without requiring complex manual intervention or additional hardware components.
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 allows for moderate shifting operations while avoiding sudden deceleration, enhancing user safety and convenience by maintaining performance protection of the continuously variable transmission, even during abnormal conditions, and preventing slips within the transmission.
Implementation Method 1
a hydraulic pressure supplier configured to supply hydraulic pressure
Implementation Method 2
The solenoid valve converts an electric control signal derived from a control unit into the hydraulic pressure
Data Source
AI summary
A control apparatus of a continuously variable transmission includes a shifting controller and a detector. The continuously variable transmission includes a hydraulic pressure supplier and a continuously variable transmission unit. The continuously variable transmission unit is able to perform continuously variable shifting by a hydraulic pressure in the hydraulic pressure supplier. The shifting controller causes, when the detector detects an abnormality, the hydraulic pressure in the hydraulic pressure supplier to fall within a range that is equal to or greater than a first value and less than a second value. The first value is a value at which minimal operation performed by the continuously variable transmission unit is available. The second value is a value upon normal operation before the detector detects the abnormality.