Transmission Shift Control via Dynamic Gradient Monitoring
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Solution Overview
Problem
Automatic transmissions with friction-locking and form-locking shift elements face issues with shifting comfort due to time delays in engaging form-locking shift elements, especially when there are spontaneous changes in transmission input speed, leading to rotational speed differentials outside desired windows, causing shifting noises and torque reactions.
Innovation Solution
A method that adjusts the time period between shift request and engagement of form-locking shift elements by monitoring the actual gradient and comparing it to the initial gradient, allowing for correction or varying the engagement speed to maintain the rotational speed differential within a predefined window, ensuring comfortable shifting by adjusting the actuating force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed time delay is used for engaging form-locking shift elements, then the shift control is simple, but the rotational speed differential may fall outside the desired window causing shifting noises and torque reactions
Solution Approach 1:
The patent applies dynamics by making the time delay variable rather than fixed. The control unit continuously monitors the actual gradient of transmission input speed and dynamically adjusts the time delay for engaging form-locking shift elements based on real-time operating conditions. This ensures the rotational speed differential remains within the desired window even when spontaneous speed changes occur, thereby preventing shifting noises and torque reactions while maintaining simple shift control logic.
Solution Approach 2:
The patent implements feedback by continuously monitoring the actual gradient of transmission input speed and using this information to adjust the engagement timing of form-locking shift elements. The control unit compares the actual gradient with the gradient at the time of shift request and modifies the time delay accordingly. This closed-loop feedback mechanism ensures optimal engagement timing that prevents harmful shifting noises and torque reactions while maintaining simple control architecture.
2Ease of operation
If the time delay is adjusted based on the gradient at shift request time, then shifting comfort can be maintained under normal conditions, but spontaneous changes in transmission input speed cannot be taken into account
Solution Approach 1:
The patent resolves this contradiction by making the time delay dynamically adjustable based on real-time monitoring of transmission input speed gradient. Instead of relying solely on the gradient at shift request time, the control unit continuously tracks actual gradient changes and adapts the engagement timing accordingly. This dynamic adjustment maintains shifting comfort under normal conditions while simultaneously providing adaptability to spontaneous speed changes through real-time feedback.
Solution Approach 2:
The patent applies feedback by implementing continuous monitoring of the actual gradient of transmission input speed during the shift process. The control unit uses this real-time feedback to adjust the time delay for engaging form-locking shift elements, ensuring that both shifting comfort under normal conditions and adaptability to spontaneous speed changes are achieved. The feedback mechanism allows the system to respond to actual operating conditions rather than relying on pre-calculated timing based solely on initial gradient.
3Reliability
If a longer time period is used for shift engagement, then synchronization is improved, but the engagement time may no longer coincide with the optimal rotational speed differential window
Solution Approach 1:
The patent resolves this contradiction by making the time period dynamically adjustable rather than fixed or solely gradient-dependent. The control unit monitors the actual gradient during the shift process and dynamically modifies the engagement timing to ensure it coincides with the optimal rotational speed differential window. This dynamic adjustment maintains synchronization quality while preventing loss of timing accuracy even when spontaneous speed changes occur during the shift process.
Solution Approach 2:
The patent applies feedback by continuously monitoring the actual gradient of transmission input speed and using this information to adjust the engagement timing of form-locking shift elements. This feedback mechanism ensures that the time period is optimized in real-time, maintaining both synchronization quality and engagement timing accuracy. The system can accommodate longer time periods when needed for synchronization while automatically adjusting to maintain optimal timing through continuous gradient monitoring and adaptive control.
Data Source
AI summary
A method of operating a transmission device comprising friction-locking and form-locking shift elements for obtaining different gear ratios. A shift request for engaging a shift element undergoes a time delay dependent upon an operating state prior to a time of engagement of the shift element. A rotational speed differential between halves of the shift element lies within a rotational speed differential window required for the engagement procedure is assigned to the time of engagement. A gradient of the transmission input speed is ascertained at the time of the shift request, and the actual gradient is subsequently monitored and compared with the gradient that existed at the time of the shift request. If an absolute deviation greater than a threshold value is ascertained, the time delay is changed or an actuation of another shift element to be disengaged is varied such that the deviation is reduced below the threshold value.