Hybrid Vehicle Shift Threshold Control via Kink Speed
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Solution Overview
Problem
Current methods for optimizing gear shifts in electric and hybrid vehicles with automatic transmissions are costly and do not efficiently utilize the power potential of electric motors, as they rely on static shift thresholds that do not account for varying influencing parameters, leading to suboptimal exploitation of mechanical propulsion power and efficiency.
Innovation Solution
The method involves using the kink speed, at which the electric motor provides maximum power, as the sole parameter to vary the shift threshold, allowing the control device to adapt shift speeds and optimize power utilization by considering variables like battery state, temperature, and transmission conditions, thereby ensuring the power maximum is within the available speed range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple influencing parameters are considered with correction factors for optimizing shift lines, then the precision of power optimization is improved, but the device complexity and computational cost increase
Solution Approach 1:
The patent extracts only the most critical parameter (kink speed) from the multiple influencing parameters, eliminating the need to process battery temperature, state of charge, and other variables. This extraction approach maintains power optimization precision while dramatically simplifying the control system complexity.
Solution Approach 2:
The patent uses pre-calculated shift lines stored in the control device that represent optimal shift characteristics under various conditions. Instead of performing complex real-time calculations with multiple parameters, the system copies and applies pre-determined shift lines based on the current kink speed, reducing computational burden while maintaining optimization precision.
2Device complexity
If a static shift threshold is used in the transmission control, then the device complexity is reduced, but the power utilization efficiency deteriorates
Solution Approach 1:
The patent implements dynamic shift threshold adjustment by varying the shift threshold as a function of kink speed. Instead of using a fixed static threshold, the control device dynamically adapts the shift point based on the electric motor's operating characteristics, ensuring optimal power utilization while maintaining relatively simple control logic.
Solution Approach 2:
The patent changes the shift threshold parameter based on the kink speed parameter. By adjusting the shift threshold according to the motor's power characteristics at different speeds, the system optimizes power utilization without requiring complex multi-parameter control, achieving a balance between simplicity and efficiency.
3Adaptability or versatility
If the shift threshold is varied based on multiple parameters, then the adaptability to operating conditions is improved, but the ease of operation and control complexity increase
Solution Approach 1:
The patent extracts and focuses solely on the kink speed parameter as the basis for adapting shift characteristics to operating conditions. This single-parameter approach provides sufficient adaptability to varying motor characteristics while keeping the control system easy to operate and understand, avoiding the complexity of multi-parameter control.
Data Source
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AI summary
The invention relates to a method for operating an electric or hybrid vehicle with shif table transmission, in which at least one electric motor is employed for propelling the vehicle. Upon reaching a shift threshold, a shift operation is performed in the transmission of the vehicle, wherein a value specifying the shift threshold is varied depending on at least one parameter. As the at least one parameter, a speed (26, 36) is used, at which a power provided by the at least one electric motor for propelling the vehicle has a maximum (30, 38). Furthermore, the invention relates to an electric or hybrid vehicle.