Double Swap Kickdown Shift Control via RPM Overshoot
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Solution Overview
Problem
Typical double swap shifts in automatic transmissions result in unpredictable timing, leading to rough shifts, energy wastage, and reduced vehicle performance due to inefficient clutch control logic.
Innovation Solution
A method for performing a double swap downshift by modulating the release and application of clutches in a main box and compounder box to achieve a predetermined RPM overshoot, ensuring smooth and predictable shifts while minimizing clutch energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If typical double swap shift logic is used, then gear ratio changes are achieved, but shift timing becomes unpredictable causing rough shifts and jerky ride
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal shift timing parameters and clutch control sequences in a lookup table before operation. During actual shifts, the controller simply retrieves pre-determined timing parameters based on current gear state, ensuring predictable and smooth shift timing without real-time calculation complexity.
Solution Approach 2:
The patent changes parameters by using a lookup table that stores pre-determined shift timing parameters for different gear transitions. The controller selects appropriate timing parameters from the table based on current and target gear states, optimizing shift smoothness and predictability for each specific gear change scenario.
2Adaptability or versatility
If typical double swap shift logic is used, then gear ratio changes are achieved, but shift completion time is slow wasting energy and wearing clutches
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal shift timing parameters and clutch control sequences in a lookup table before operation. During actual shifts, the controller simply retrieves pre-determined timing parameters based on current gear state, ensuring predictable and smooth shift timing without real-time calculation complexity.
Solution Approach 2:
The patent applies skipping by implementing optimized clutch control sequences that rapidly transition clutches through intermediate states to achieve gear changes faster. The lookup table provides pre-determined timing that minimizes the duration of clutch slip and engagement, rushing through the shift process to reduce energy waste and clutch wear.
3Adaptability or versatility
If double swap shifts are used, then unavailable gear ratios become accessible, but clutch manipulation complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal shift timing parameters and clutch control sequences in a lookup table before operation. During actual shifts, the controller simply retrieves pre-determined timing parameters based on current gear state, ensuring predictable and smooth shift timing without real-time calculation complexity.
Solution Approach 2:
The patent applies self-service by using a lookup table that automatically provides the correct clutch control sequence and timing parameters based on the current gear state and desired target gear. The system serves itself by retrieving pre-stored optimization data without requiring complex real-time decision-making or additional computational resources.
Data Source
AI summary
A method of performing a double swap kickdown shift in a transmission having a main box and a compounder. The compounder is shifted during the hold speed phase of the downshift. The target ratio for the downshift is overshot by an overshoot RPM.