Automatic Gearbox Sport Mode Upshift for Engine Overspeed Control
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Solution Overview
Problem
Existing methods for controlling transmission ratio changes in automatic gearboxes for motor vehicles do not effectively manage engine speed beyond the maximum authorized breakaway speed, especially when the sporty driving mode is activated, leading to potential engine overspeed and instability.
Innovation Solution
A method and system that compare engine speed with the maximum authorized breakaway speed, verify the activation of sporty driving mode, and automatically force an upshift after a time delay when the engine speed exceeds the breakaway speed, using a correction module with logic gates and a timer to manage gear changes based on current gear ratio and driver input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the driver manually requests an upshift in assisted manual mode, then the driver has control over gear selection, but the engine speed may exceed the maximum authorized breakaway speed causing overspeed and potential damage
Solution Approach 1:
The control system continuously monitors engine speed and compares it with the maximum authorized breakaway speed. When the engine speed exceeds the threshold, the system automatically intervenes by forcing an upshift, creating a feedback loop that prevents overspeed while respecting the driver's manual mode selection. This resolves the contradiction by maintaining driver control through assisted manual mode while adding automatic protection when safety thresholds are exceeded.
2Reliability
If forced upshifts are implemented when engine speed exceeds maximum breakaway speed, then engine overspeed is prevented, but the gear change may cause instability or jerky operation
Solution Approach 1:
The control system prepares for the forced upshift by monitoring engine speed approaching the maximum breakaway threshold. When the threshold is exceeded, the upshift is executed promptly to prevent prolonged overspeed operation. The timing is optimized to balance protection needs with operational smoothness, resolving the contradiction between preventing overspeed and maintaining stable transmission operation.
3Reliability
If automatic upshift forcing is implemented in sporty driving mode, then engine speed is controlled beyond maximum breakaway speed, but the driver's sporty driving experience is compromised
Solution Approach 1:
The control system adapts its behavior based on the selected driving mode. In sporty driving mode, the system allows engine operation closer to the maximum breakaway speed threshold before forcing an upshift, providing a more dynamic and engaging driving experience. The threshold and response characteristics are dynamically adjusted according to the driving mode, resolving the contradiction between protection and sporty performance by making the protection adaptive rather than fixed.
Data Source
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AI summary
The invention relates to a method for controlling gear ratio shifts of a power unit for a motor vehicle equipped with an automatic gearbox, comprising, in assisted manual control mode: a step of comparing the engine speed of the power unit to a maximum circuit breaker speed authorised for the unit; a step of checking the activation by the driver of a sport driving mode; and a step of correcting the gear ratio engaged so that an upshift is automatically triggered when the sport driving mode is activated and when the engine speed of the power unit is greater than the maximum circuit breaker speed.