Vehicle Gear Shift Control Unit Preventing Engine Stall
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Solution Overview
Problem
During gear shifting in vehicles, especially under heavy load or uphill conditions, drivers face challenges in determining whether to shift gears, leading to engine stalling due to insufficient tractive force, which increases the risk of accidents and results in inefficient fuel consumption.
Innovation Solution
A method and control unit that determine the engine's rpm range for gear engagement, simulate the shift to predict the lowest rpm post-shift, and calculate a threshold rpm for propulsive force, adjusting gear-shifting performance to ensure the predicted rpm meets or exceeds the threshold, thereby preventing engine stalling and optimizing fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the driver shifts gears under heavy load or uphill conditions without proper prediction, then the vehicle may achieve better fuel efficiency and lower engine rpm, but the engine may stall due to insufficient tractive force
Solution Approach 1:
The control unit performs a prediction calculation before executing the gear shift to determine whether the engine rpm will remain above the threshold value after shifting. This preliminary assessment prevents shifts that would cause engine stalling while allowing shifts that improve fuel efficiency, thereby resolving the contradiction between fuel efficiency and reliability.
2Reliability
If the driver constantly drives in a lower gear at higher rpm to avoid engine stalling, then the risk of accident is reduced, but fuel consumption increases
Solution Approach 1:
The control unit continuously monitors engine rpm, vehicle speed, load conditions, and slope information, and uses this feedback to dynamically determine the threshold rpm value and predict whether a gear shift is safe. This feedback mechanism allows the system to optimize fuel efficiency by enabling gear shifts when conditions permit, while maintaining reliability by preventing shifts that would cause stalling.
3Ease of operation
If the gear shift is performed slowly and cautiously to prioritize passenger comfort, then comfort is improved, but the vehicle loses too much velocity and the shift becomes unsuccessful
Solution Approach 1:
The control unit dynamically adjusts the gear shift performance characteristics based on predicted engine rpm and threshold values. When the prediction indicates sufficient margin above the threshold, the system can perform faster shifts that maintain velocity. When the margin is smaller, the system performs slower, more gradual shifts that prioritize comfort. This dynamic adjustment resolves the contradiction between comfort and velocity maintenance.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A method (400) and control unit (115) for shifting gears of a transmission (113) in a vehicle (100). The method (400) comprises determining (401) that the rpm level of the vehicle engine (110) lies within an rpm range (210) for engaging a new gear, predicting (402), by simulating the shift of gears, what the lowest rpm (220) would be after a shift to the new gear were the shift to be performed, calculating (403) a threshold rpm (230) at which the vehicle engine (110) will generate a propulsive force corresponding to the running resistance of the vehicle, and increasing (404) the gear-shifting performance so that the predicted (402) lowest rpm (220) will equal or exceed the threshold rpm (230) so that the shift can be performed if the predicted (402) lowest rpm (220) is below the calculated (403) threshold rpm (230).