Transmission Control Module Adjusting Deceleration Shift Points
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Solution Overview
Problem
In multi-speed transmissions, maintaining a target minimum turbine speed during engine deceleration is challenging, especially with increasing gear ratios, which affects vehicle responsiveness, fuel economy, and shifting smoothness.
Innovation Solution
A method that adjusts deceleration-dependent shift points by calculating a vehicle speed offset based on acceleration rate and predicted downshift delay, converting turbine speed to vehicle speed, and determining a target gear to maintain a minimum turbine speed, while considering brake status, deceleration rate, and diesel particulate filter regeneration conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If deceleration-dependent shift points are adjusted to maintain target minimum turbine speed, then vehicle responsiveness is improved, but transmission control complexity increases
Solution Approach 1:
The system pre-calculates and stores shift points for different deceleration conditions in lookup tables before operation. During actual deceleration events, the control module simply retrieves pre-computed shift points based on current conditions, avoiding complex real-time calculations and reducing control complexity while maintaining responsive shifting
Solution Approach 2:
The invention dynamically adjusts shift points based on deceleration rate parameters. By changing the shift point parameters according to measured deceleration conditions, the system optimizes turbine speed maintenance without requiring complex control algorithms, achieving improved responsiveness through parameter adaptation
2Use of energy by moving object
If multiple gear ratios are added to improve fuel economy, then fuel efficiency is improved, but the difficulty of choosing appropriate gear increases
Solution Approach 1:
The transmission control module continuously monitors turbine speed, vehicle speed, and deceleration rate, then uses this feedback to automatically select appropriate shift points from pre-computed tables. This closed-loop feedback system manages the complexity of multiple gear ratios by using sensor data to drive automatic gear selection, improving fuel efficiency without burdening the driver with manual gear management
Solution Approach 2:
The deceleration-based shift control system serves multiple functions simultaneously: it maintains turbine speed within optimal ranges, improves fuel efficiency across various driving conditions, and provides smooth shifting. This multi-functional approach allows a single control strategy to handle the complexities of multiple gear ratios while delivering comprehensive performance benefits
3Reliability
If shift points are adjusted to maintain minimum engine speed during deceleration, then engine stall protection is improved, but shifting smoothness may be compromised
Solution Approach 1:
The system dynamically adjusts shift points based on real-time deceleration conditions rather than using fixed shift schedules. By making shift points dynamic and adaptive to current deceleration rates, the system can prevent engine stall under heavy deceleration while maintaining smooth shifting characteristics during gentle deceleration, resolving the contradiction between protection and smoothness
Solution Approach 2:
The invention segments the deceleration control strategy into distinct lookup tables for different deceleration conditions (e.g., mild deceleration, moderate deceleration, heavy deceleration). Each table contains optimized shift points for its specific condition range, allowing the system to select the appropriate segment based on current deceleration rate, thereby maintaining both stall protection and shifting smoothness across varying conditions
Data Source
AI summary
A method of adjusting deceleration dependent shift points to maintain a target minimum turbine speed includes calculating a vehicle speed offset based on vehicle acceleration rate a predicted downshift delay for the target minimum turbine speed and converting the target minimum turbine speed to a target vehicle speed based on the deceleration condition. Thereafter, the method continues with determining a target gear based on the vehicle speed offset and the target vehicle speed, and downshifting to the target gear having vehicle speed less than or equal to a vehicle speed corresponding to the current turbine speed. The method ends with maintaining the target gear until a shift delay period is greater than a predetermined delay threshold.