Power Split Transmission Range Shift Interruption
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Solution Overview
Problem
Power-split transmissions struggle to provide immediate and responsive reactions to driver inputs, particularly when driver requirements change during shifting between ranges, as transmission ratio changes can only occur after range shifts are completed.
Innovation Solution
The method involves an electronic control unit that monitors driver inputs and interrupts range shifts if requirements change, allowing for immediate adjustment of the transmission ratio by pre-filling and actuating clutches, maintaining constant ratios during shifts, and blocking shifts to prevent alternation, enabling rapid response to driver demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmission keeps the transmission ratio constant during range shift to achieve smooth shifting, then shift quality is improved, but the response to driver inputs is delayed
Solution Approach 1:
The system dynamically adjusts the transmission ratio control strategy based on driver input detection. During range shifts, if driver requirements change (accelerator pedal release, brake activation, reverse command), the system transitions from maintaining constant transmission ratio to allowing immediate transmission ratio changes, making the system adaptable to changing operational conditions
Solution Approach 2:
The electronic control unit continuously monitors driver inputs (accelerator pedal position, brake activation, reverse gear command) and uses this feedback to determine whether to interrupt the ongoing range shift. This feedback mechanism enables the system to respond to driver intentions in real-time, resolving the contradiction between smooth shifting and responsive control
2Adaptability or versatility
If the range shift is completed fully to enable transmission ratio change, then transmission ratio adjustment is achieved, but the shift time is extended
Solution Approach 1:
The system performs preliminary detection of driver inputs during the range shift process. By monitoring accelerator pedal release, brake activation, or reverse commands before the range shift completes, the system can interrupt the shift early and initiate transmission ratio adjustment without waiting for the full shift duration, reducing time loss while maintaining adaptability
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
This approach ensures the vehicle reacts promptly to driver inputs by allowing immediate transmission ratio adjustments during shifts, enhancing driver control and reducing shift times by discontinuing incomplete shifts and re-initiating them as needed.
Implementation Method 1
the range clutch to be engaged is pre-filled with hydraulic fluid and then actuated in the closing direction until it has closed
Implementation Method 2
a hydrostatic-mechanical power-split transmission of this type, in which the shift from a first driving range to a second driving range takes place with synchronous rotational speed
Data Source
AI summary
During a shift from a first driving range to a second driving range in a continuously variable power-split transmission having a continuously variable branch and a mechanical branch, in which during the range shift, the synchronous rotation speed is kept constant, the range shift is discontinued if a predefined threshold of at least one driving requirement is exceeded.