Automatic Transmission Speed-Ratio Control via Signal Duration Threshold
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Solution Overview
Problem
Modern automatic transmissions in vehicles lack a precise method for controlling speed-ratio changes based on operator input, often resulting in unintended shifts that can lead to engine damage or stall, due to the lack of a standardized threshold for determining the duration of operator signals.
Innovation Solution
A method and system where a controller in a vehicle receives an input signal from a switch with a determinable duration, compares it to a threshold duration, and commands the transmission to change speed-ratios accordingly, denying additional shift requests if the threshold is exceeded to prevent excessive changes that could harm the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the transmission allows manual speed-ratio selection without duration threshold control, then the operator has full control over gear changes, but unintended shifts may occur leading to engine damage or stall
Solution Approach 1:
The controller measures the duration of the operator's input signal before executing the speed-ratio change. This preliminary measurement action ensures that only intentional, sustained inputs trigger shifts, preventing accidental activations that could lead to engine damage or stall while maintaining operator control
2Productivity
If the transmission uses automatic speed-ratio selection, then the engine operating range is optimized, but the operator cannot manually control specific gear ranges
Solution Approach 1:
The system dynamically switches between automatic and manual control modes based on operator input. The duration threshold mechanism allows the operator to temporarily override automatic selection with manual commands, providing adaptability that satisfies both automatic optimization and manual control needs
3Adaptability or versatility
If the transmission responds to every short-duration switch signal, then all operator inputs are registered, but excessive speed-ratio changes may harm the engine
Solution Approach 1:
The controller uses duration as a discriminating parameter to filter operator inputs. By establishing a threshold duration value, the system distinguishes between intentional shifts (longer duration) and accidental inputs (shorter duration), allowing versatile response to valid commands while blocking harmful excessive changes
Data Source
AI summary
A method of controlling an automatic transmission connected to an engine in a motor vehicle employs a switch for requesting selection of transmission speed-ratio ranges. According to the method, the switch receives an input signal and generates an output signal having the same duration as the input signal. A controller programmed with an engine threshold speed and a threshold signal duration receives and compares the output signal with the threshold signal duration. The controller also determines a current transmission speed-ratio range and a transmission threshold speed-ratio range that is defined by engine's threshold speed. The controller additionally commands the transmission to change the current speed-ratio range to a neighboring speed-ratio range if the signal duration is less than or equal to the threshold. Furthermore, the controller commands the transmission to change the current speed-ratio range to the threshold speed-ratio range if the signal duration is greater than the threshold.