Real-Time Transmission Shift Point Adjustment Based on Engine Torque
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Solution Overview
Problem
Conventional transmission shift schedules struggle to adapt to varying engine performance curves, particularly with modern engines producing peak power at speeds less than full load governing speed, leading to suboptimal shifting and increased emissions and fuel consumption.
Innovation Solution
A method for determining and setting shift points in real-time based on input torque data and engine performance curves, using a transmission controller to calculate gear step values and adjust shift points to match engine power and speed conditions, ensuring optimal shifting across different engine torque and power curves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If transmission shift schedules are based on conventional full load governing speed, then shifting occurs at peak power points, but this approach fails to adapt to modern engines that produce peak power at speeds less than full load governing speed, leading to suboptimal fuel economy and increased emissions
Solution Approach 1:
The transmission control system dynamically adapts shift schedules in real-time based on the actual engine performance curve. Instead of using fixed shift points based on full load governing speed, the system continuously monitors engine torque and power characteristics and adjusts shift points to match the actual peak power speed, which may be lower than full load governing speed in modern engines.
Solution Approach 2:
The system changes the shift point parameters based on the engine's actual performance characteristics. By calculating the gear step value and comparing power values at different speeds, the system determines optimal shift points that correspond to the actual peak power speed of the engine, rather than relying on predetermined full load governing speed values.
2Device complexity
If transmission shift points are fixed based on full load governing speed, then the control system is simple, but it cannot accommodate engines with varying performance curves, reducing performance optimization
Solution Approach 1:
The transmission control system performs self-adjustment by automatically determining optimal shift points based on real-time engine performance data. The system calculates gear step values, compares power values at different speeds, and sets shift points without requiring complex external calibration or pre-programmed schedules for each engine type.
Solution Approach 2:
The system uses feedback from engine torque and power measurements to continuously optimize shift points. By monitoring the actual engine performance curve and comparing it with the transmission's current shift schedule, the system adjusts shift points to ensure they align with peak power delivery, improving overall vehicle performance.
3Power
If transmission shifts occur near full load governing speed to maintain power continuity, then conventional shift schedules work for traditional engines, but they fail to optimize performance for modern engines with lower peak power speeds
Solution Approach 1:
The system performs preliminary calculations to determine the optimal shift point before executing the shift. By calculating the gear step value and comparing power values at different speeds in advance, the system identifies the speed at which power continuity is maintained, then uses this information to set the appropriate shift point that matches modern engine characteristics.
Data Source
AI summary
A method for setting a shift point for shifting a transmission for a powered vehicle between a first gear ratio and a second gear ratio. The method includes determining input power data points based on real-time input torque data. The input torque data includes a maximum input torque. The method also includes calculating a gear step value based on the first gear ratio and second gear ratio. The method further includes determining a first power value and computing a second power value based on the gear step value. The first power value and second power value are compared to one another and adjustments are incrementally made in the first power value speed until the difference between first and second power values meets a threshold. The shift point is therefore based on the result of comparing the first power value and the second power value and the corresponding speed associated with the first power value.