Predictive Gear Shift Control to Prevent Engine Stalling
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Solution Overview
Problem
During gear shifting in vehicles, especially under heavy load or uphill conditions, there is a risk of engine stalling due to insufficient tractive force, leading to increased accident risk and inefficient fuel consumption, as drivers struggle to determine whether to shift gears effectively.
Innovation Solution
A method and control unit that determine if the engine RPM is within a suitable range for gear engagement, predict the lowest RPM post-shift, and calculate a threshold RPM for propulsive force, preventing shifts if the predicted RPM is below the threshold to avoid engine stalling and unnecessary low gear driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the driver shifts to a higher gear to reduce fuel consumption and engine noise, then fuel efficiency improves, but the engine may stall due to insufficient RPM after shifting
Solution Approach 1:
The control unit performs a predictive simulation of the gear shift before actually executing it. By calculating the predicted lowest RPM after the shift and comparing it against a threshold RPM, the system determines in advance whether the shift would cause engine stalling. This preliminary assessment allows the system to prevent harmful shifts while permitting beneficial ones, thus reducing fuel consumption without compromising engine reliability.
2Reliability
If the driver maintains higher RPM to prevent engine stalling, then engine reliability is maintained, but fuel consumption increases
Solution Approach 1:
The system continuously monitors actual engine parameters (RPM, load, vehicle speed) and compares them against predicted values from the simulation model. This feedback mechanism allows the control unit to learn from actual shifting outcomes and refine its predictions, enabling more accurate determination of safe shift points that prevent stalling while minimizing fuel consumption.
3Reliability
If the system prevents gear shifts to avoid engine stalling, then engine reliability improves, but driving efficiency and productivity decrease
Solution Approach 1:
The system dynamically adjusts the gear shift decision based on multiple varying parameters including current RPM, vehicle load, vehicle speed, and road gradient. By considering these changing parameters in the predictive simulation, the system can identify optimal shift opportunities that maintain engine reliability while preserving driving efficiency, rather than applying a conservative fixed threshold that would limit productivity.
4Reliability
If the driver downshifts to maintain propulsive force, then engine reliability is maintained, but fuel consumption increases due to unnecessarily high RPM
Solution Approach 1:
The system creates a virtual copy or simulation model of the gear shifting process that mirrors the actual physical system. By running predictions in this simulated environment, the control unit can evaluate the consequences of potential shifts without affecting the actual engine operation, enabling informed decisions that optimize both reliability and fuel efficiency.
Data Source
Figure 1A~1B
Figure 1C
Figure 2
AI summary
A method (300) and control unit (115) for shifting gears of a transmission (113) in a vehicle (100). The method (300) comprises determining (301) that the rpm level of the vehicle engine (110) lies within an rpm range (210) for engaging a new gear, predicting (302), 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 (303) a threshold rpm (230) at which the vehicle engine (110) will generate a propulsive force corresponding to the running resistance of the vehicle, and preventing (304) a shift to the new gear when the predicted (302) lowest rpm (220) is below the calculated (303) threshold rpm (230).