Transmission Controller Shift Schedule Selection
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Solution Overview
Problem
Existing methods for selecting shift schedules in transmissions lack accuracy due to reliance on inaccurate assumptions, leading to inefficient vehicle operation under varying conditions.
Innovation Solution
A system and method that estimates vehicle mass and terrain grade using multiple accelerations and road load calculations, allowing the controller to select between performance and economy shift schedules based on these parameters and the vehicle's capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the transmission shifts gears at lower engine speeds to improve efficiency, then fuel efficiency is improved, but vehicle performance suffers under heavy load or steep grades
Solution Approach 1:
The transmission control system dynamically adjusts gear shift timing based on real-time operating conditions. The controller monitors vehicle load, terrain grade, and driving conditions to determine whether to shift at lower engine speeds (for efficiency) or maintain higher engine speeds (for performance). This dynamic adaptation resolves the contradiction by making the shift schedule flexible rather than fixed.
Solution Approach 2:
The system changes the shift schedule parameters (engine speed at which gear shifts occur) based on detected operating conditions. When heavy load or steep grade is detected, the controller modifies the shift points to occur at higher engine speeds to maintain performance. When conditions are favorable, shifts occur at lower engine speeds to improve fuel efficiency.
2Ease of operation
If the transmission uses fixed shift schedules, then the system is simple to operate, but it cannot adapt to varying vehicle loads and terrain conditions
Solution Approach 1:
The transmission control system incorporates feedback from various sensors that monitor vehicle operating conditions including engine load, vehicle speed, and terrain characteristics. The controller continuously receives this feedback and adjusts the shift schedule accordingly, enabling the system to automatically adapt to changing conditions while maintaining ease of operation.
Solution Approach 2:
The transmission system performs self-adjustment based on detected conditions without requiring manual intervention. The controller automatically selects appropriate shift schedules by monitoring operating parameters and making real-time decisions, allowing the system to serve itself in adapting to varying loads and terrain.
3Power
If the transmission selects gear for improved performance under heavy load, then vehicle power output is improved, but fuel efficiency deteriorates
Solution Approach 1:
The controller modifies shift schedule parameters based on detected vehicle load and terrain conditions. When heavy load or steep grade is detected, the system changes the shift points to occur at higher engine speeds to maintain performance. When conditions are favorable, shifts occur at lower engine speeds to improve fuel efficiency.
Solution Approach 2:
The transmission control system dynamically adjusts gear shift timing based on real-time operating conditions. The controller monitors vehicle load, terrain grade, and driving conditions to determine whether to shift at lower engine speeds (for efficiency) or maintain higher engine speeds (for performance).
Data Source
AI summary
A system for selecting shift schedules of a transmission of a vehicle configured to change gears according to two or more shift schedules includes a controller. The controller is configured to estimate mass of the vehicle based on a plurality of accelerations of the vehicle from a standstill, and estimate a road load of the vehicle based on the estimated mass. The controller is also configured to estimate a grade of terrain over which the vehicle is travelling based on the estimated mass of the vehicle. The controller is further configured to select between at least a first shift schedule and a second shift schedule based on at least one of the estimated mass of the vehicle, characteristics of the terrain over which the vehicle is travelling, the estimated grade of the terrain over which the vehicle is travelling, and functions capable of being performed by the vehicle.