Shift Element Sensor Reference Adaptation Across Temperature and Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The accurate determination of the operating condition of form-locking shift elements in transmissions is hindered by service life drift, temperature-dependent, and system pressure-dependent tolerances, leading to inaccuracies in position determination and potential mechanical malfunctions.
Innovation Solution
A method that subdivides the operating range of the shift element into temperature and pressure classes, adjusts operating parameters such as torque and actuation force, and adapts reference values based on deviations to compensate for these tolerances, ensuring precise determination of end positions and reliable transition between engaged and disengaged states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If form-locking shift elements are used to eliminate drag torques, then transmission efficiency is improved, but the shift element can only be transferred into engaged condition close to synchronous speed and may not be disengageable under all torque conditions
Solution Approach 1:
The patent introduces a friction-locking shift element in combination with the form-locking shift element. The friction-locking element provides dynamic torque transmission capability across a wide operating range, while the form-locking element provides precise positioning. This dynamic combination allows the transmission system to adapt to various torque conditions and speed ranges, resolving the limitation of form-locking elements being restricted to synchronous speed operation.
2Measurement precision
If sensor reference values are not adapted for service life drift and environmental factors, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent implements preliminary characterization of the sensor system during manufacturing, establishing baseline reference values and tolerance ranges before service life drift occurs. This preliminary action creates a foundation for later adaptation, allowing the system to compensate for environmental factors and service life drift by comparing current readings against pre-established reference ranges, thereby maintaining measurement precision without requiring complex real-time calibration systems.
Solution Approach 2:
The patent introduces adaptation of reference values based on temperature and pressure parameters. By monitoring environmental parameters and adjusting reference values accordingly, the system compensates for thermal expansion, pressure effects, and service life drift. This parameter-based adaptation maintains measurement precision while avoiding the need for complex mechanical adjustment mechanisms.
3Reliability
If tolerance ranges for sensor values are established to account for service life drift and environmental factors, then reliability is improved, but the determination process becomes more complex
Solution Approach 1:
The patent establishes tolerance ranges that are sufficient to cover service life drift and environmental variations without being overly conservative. By setting appropriately sized tolerance windows around reference values, the system achieves reliable operation under varying conditions while avoiding excessive complexity in the evaluation logic. The tolerance ranges are calibrated to provide adequate margin for drift while maintaining clear decision boundaries for engaged/disengaged states.
Data Source
AI summary
A method for determining reference values of a sensor corresponding to a disengaged operating condition or to an engaged operating condition of a hydraulically actuatable, form-locking shift element (A, F), where at least one operating parameter of the form-locking shift element (A, F) is detected with the sensor during a disengagement and during an engagement of the form-locking shift element (A, F). The method may include subdividing an operating range of the shift form-locking element (A, F) into temperature and pressure classes. The method may further include determining a deviation between a current reference value for a temperature and pressure class of the temperature and pressure classes and an adapted reference value previously determined for the temperature and pressure class. Additionally, the method may include increasing or decreasing the adapted reference value by a predefined increment based on the deviation.