Transmission Shift Element Position Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for automatic transmissions, such as those using positive-locking shifting elements like claw couplings, cannot accurately determine the initial position of shifting elements, particularly when they are in an end stop position, due to limitations in pressure sensor detection.
Innovation Solution
A method that records the operating pressure curve to determine the initial position of shifting elements, involving three phases: applying current and recording pressure, evaluating pressure thresholds, and checking for defects, allowing determination of the shifting element's position and direction of movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensor detection is used to detect relative movements of shifting elements, then movement detection capability is provided, but the initial position and end stop position cannot be determined
Solution Approach 1:
The patent applies preliminary action by performing a specific initialization sequence before normal operation: applying operating pressure to all shifting elements, waiting for a predetermined time, and detecting which elements remain in the end stop position. This preliminary detection phase establishes the initial position information that would otherwise be lost, enabling subsequent accurate position and direction determination during normal operation.
2Ease of operation
If the transmission system is pressurized to operate shifting elements, then shifting elements can be actuated, but the initial position determination becomes complex requiring multiple detection phases
Solution Approach 1:
The patent segments the position determination process into three distinct phases: (1) pressurization phase where operating pressure is applied to all shifting elements, (2) detection phase where pressure sensor readings determine which elements are in the end stop position, and (3) initialization phase where the detected positions are stored as initial positions. This segmentation transforms a complex simultaneous determination problem into manageable sequential steps, reducing overall system complexity while maintaining accuracy.
3Extent of automation
If a predetermined time interval is used to determine initial position, then position assignment can be automated, but defect detection requires additional time and measures
Solution Approach 1:
The patent implements feedback by continuously monitoring pressure sensor readings during the predetermined time interval and comparing them against expected values. If the pressure readings indicate that shifting elements fail to reach their expected end stop positions within the time interval, the system automatically triggers a defect detection routine. This feedback mechanism ensures reliable defect detection while maintaining automated operation, as the system adapts its behavior based on real-time sensor data without requiring manual intervention.
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
Enables accurate determination of the initial position and direction of shifting elements, identifying end stop positions and detecting potential defects, ensuring reliable operation of automatic transmissions.
Implementation Method 1
A pressure sensor is provided for detecting relative movements of the shifting elements; this records the operating pressure of the respective shifting element
Data Source
AI summary
A method for recording an initial position of at least one positive-locking shifting element of a transmission of a vehicle is proposed, whereas an initial position of the shifting element is determined and assigned depending on a recorded operating pressure curve for the actuation of the shifting element.