Automatic Transmission Gear Shift Control for Deceleration
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Solution Overview
Problem
Existing automatic transmission gear shift control systems often result in undesirable frequent gear shifts during sudden deceleration, leading to uncomfortable rides and poor maneuverability, as they fail to accurately determine deceleration rates in real-time, causing engine stalling and inadequate braking force application.
Innovation Solution
A gear shift control system that includes a speed determiner, deceleration detector, braking force determiner, and gear shift controller to immediately inhibit upshifting when deceleration exceeds a threshold, using data from brake and accelerator pedal inputs, engine torque, and regenerative braking forces to calculate and apply optimal braking forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the automatic transmission uses conventional gear shift control based on accelerator position and vehicle speed, then the transmission can automatically change gear ratios, but during sudden deceleration the vehicle experiences unwanted frequent gear shifts and engine stalling
Solution Approach 1:
The system performs preliminary detection of deceleration conditions by monitoring brake pedal input and vehicle speed changes. When deceleration exceeding a threshold is detected, the system proactively inhibits upshift operations before they can occur, preventing the harmful effect of frequent gear shifts during sudden deceleration
Solution Approach 2:
The system continuously monitors vehicle speed, brake pedal position, and calculates deceleration rates in real-time. This feedback mechanism allows the control system to dynamically adjust gear shift decisions based on actual deceleration conditions, preventing unwanted gear shifts while maintaining normal operation during other driving conditions
2Measurement precision
If the gear shift control system calculates deceleration rate using conventional methods with set time periods, then the system can determine deceleration, but the response is delayed causing undesired upshift or downshift during sudden deceleration
Solution Approach 1:
The system continuously monitors brake pedal input and vehicle speed in real-time, performing preliminary detection of deceleration conditions. When deceleration exceeding a threshold is detected, the system immediately responds by inhibiting upshift operations, eliminating the delay associated with conventional set-time period calculations
Solution Approach 2:
The system dynamically adjusts the deceleration threshold and response timing based on real-time driving conditions. By monitoring brake pedal input and vehicle speed changes continuously, the system adapts its control parameters to match the actual deceleration scenario, enabling immediate and appropriate gear shift inhibition without fixed time delays
3Force
If the automatic transmission downshifts sequentially during sudden deceleration to provide engine braking, then braking force is enhanced, but the frequent application of engine braking creates uncomfortable ride and poor maneuverability
Solution Approach 1:
The system applies preliminary anti-action by inhibiting downshift operations when excessive deceleration is detected. When the deceleration rate exceeds the predetermined threshold, the control system prevents downshift commands from being executed, thereby avoiding the harmful effect of sequential engine braking application that causes uncomfortable ride and poor maneuverability
Data Source
AI summary
A gear shift control system for vehicles is provided which mathematically calculates a rate of deceleration of the vehicle equipped an automatic transmission upon start of deceleration of the vehicle and inhibits the automatic transmission from upshifting or changes a permissible gear shift range of the automatic transmission as a function of the rate of deceleration of the vehicle, thereby ensuring a desired degree of braking force including an engine braking force while the vehicle is decelerating.