Gear Shifting Synchronization Cable for Power-Assist Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current power-assist transmissions experience delays in gear shifting due to lack of precise synchronization between the transmission and engine control units, resulting in gear shifts taking between 250 to 600 ms, which is slow for racing modes and subjects the transmission to unnecessary mechanical stress.
Innovation Solution
Implementing a dedicated electric synchronization cable for direct communication between the transmission and engine control units, allowing for rapid and precise control of drive torque and clutch operations, with predicted delay times and safety constants to ensure simultaneous but non-overlapping execution of gear shift operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a dedicated electric synchronization cable is implemented for direct communication between transmission and engine control units, then gear shifting speed is improved (reduced to less than 130-140 ms), but device complexity increases
Solution Approach 1:
The communication system is segmented into two parts: a dedicated electric synchronization cable for critical gear shift commands requiring precise timing, and the existing BUS line for other less time-critical communications. This segmentation allows the critical path to be optimized without completely replacing the existing communication infrastructure, thus reducing gear shifting time while limiting the increase in overall system complexity.
Solution Approach 2:
The dedicated electric synchronization cable acts as an intermediary communication channel specifically for time-critical signals between the transmission control unit and engine control unit. This intermediary pathway bypasses the limitations of the BUS line protocol, enabling precise synchronization of clutch release and torque reduction commands without requiring complete system redesign.
2Reliability
If predicted delay times and safety constants are used to ensure simultaneous but non-overlapping execution of gear shift operations, then reliability is improved, but device complexity increases
Solution Approach 1:
The system performs preliminary actions by pre-calculating and storing predicted delay times for clutch release and torque reduction operations. Before actual gear shift execution, the control unit retrieves these pre-determined time parameters and uses them to schedule operations in advance, ensuring they occur simultaneously but non-overlappingly. This preliminary preparation enhances reliability without requiring complex real-time calculations during the actual shift.
Solution Approach 2:
The control system incorporates feedback mechanisms where the actual execution times of clutch release and torque reduction are monitored and compared against the predicted delay times. This feedback allows the system to verify that operations are executed within the expected time windows, ensuring reliable simultaneous but non-overlapping execution. The feedback loop validates the timing parameters without adding significant complexity to the control logic.
Data Source
AI summary
A method and unit for shifting gear in a power-assist transmission; to shift gear, a series of operations are performed in sequence, and each of which must be completed prior to completion of the next operation; for each operation, a predicted time delay is estimated corresponding to the time lapse between the instant the operation is commanded and the instant the operation is actually completed; and the operations are commanded successively as a function of the predicted delay times, so that an operation is commanded before the preceding operation has actually been completed.