EV Shift Control for Skip Shifting Without Torque Shock
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Solution Overview
Problem
Conventional electric vehicles experience instability and reduced operability due to abrupt changes in drive force when shifting between torque modes or maps, leading to potential wheel slip and compromised driving behavior.
Innovation Solution
A control system that allows selective skip shifting of the operating range based on a target torque value and threshold settings, preventing consecutive shifts beyond two ranges from the current mode to maintain stability and operability, by controlling the motor's output torque in accordance with a torque map tailored to the vehicle's speed and accelerator pedal position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the operating mode is changed two times or more or shifting the operating range to the range further than two stages from the current stage within a short period of time, then the torque characteristics of the motor are changed to provide different drive forces, but the output torque of the motor changes abruptly causing drive force to change abruptly which destabilizes the electric vehicle and causes wheel slip
Solution Approach 1:
The control device predicts the target operating range before the shifting operation is completed. By determining the predicted target operating range in advance and comparing it with the current operating range, the system can assess whether a shift operation will cause abrupt torque changes before they occur, thereby preventing instability while still allowing versatile torque characteristic changes.
Solution Approach 2:
The control device continuously monitors the relationship between the predicted target operating range and the current operating range. When a manual shifting operation is detected, the system provides feedback by comparing the predicted range with the current range and automatically inhibits the shift if it would cause abrupt torque changes, thus maintaining vehicle stability while allowing adaptive torque control.
2Stability of the object's composition
If consecutive shifting operations are inhibited to prevent abrupt drive force changes, then vehicle stability is maintained, but part of the shifting operations available in conventional vehicles having transmissions have to be inhibited and hence operability of the electric vehicle has to be reduced
Solution Approach 1:
The control device performs preliminary assessment by predicting the target operating range before executing the shift. This allows the system to distinguish between beneficial shifts (those that won't cause abrupt torque changes) and harmful shifts (those that would cause instability), thereby maintaining operability while ensuring stability.
Solution Approach 2:
The system changes the parameter of torque control by using predicted target operating range comparison. Instead of simply inhibiting all consecutive shifts, the system dynamically adjusts torque control based on the predicted shift outcome, allowing operable shifts while preventing destabilizing ones, thus maintaining both stability and ease of operation.
Data Source
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AI summary
A control system for an electric vehicle for allowing a driver to virtually enjoy a manual shifting operation as performed in the conventional vehicles having transmissions without reducing stability and operability of the electric vehicle. A controller is configured to set a required drive torque in accordance with a selected operating range, and to selectively allow an execution of a skip shifting of the operating range to the range further than two ranges from the current operating range, based on the required drive torque to be set in the operating range selected by operating a shifting device consecutively.