Hybrid Vehicle EV Mode Shift Strategy for Motor Power
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Solution Overview
Problem
The available power output of a motor/generator in hybrid vehicles is limited during electric-only mode due to the need to conserve energy for transitioning to hybrid or engine-only mode, which restricts the vehicle's performance.
Innovation Solution
A controller-adjusted transmission shift strategy that narrows the operating speed range of the motor to maintain peak power output and shifts gears to increase available power when demanded power exceeds motor capabilities, accounting for the power reserve needed to start the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the motor power output is increased during EV mode, then the vehicle performance is improved, but the energy reserve required to start the combustion engine is reduced
Solution Approach 1:
The transmission shift schedule is dynamically adjusted based on operating conditions. During EV mode, the shift schedule is modified to keep the motor operating in its peak power range, allowing increased power output when needed. The controller monitors motor speed and transmission gear to selectively apply different shift schedules that optimize power delivery while preserving energy reserves.
Solution Approach 2:
The invention changes the operational parameters of the transmission system by implementing mode-specific shift schedules. When EV mode is detected, the controller applies a modified shift schedule that narrows the motor operating speed range to maintain peak power output. This parameter adjustment allows the system to extract maximum power from the motor without compromising the energy required for engine restart.
2Power
If the motor operating speed range is widened to increase power output, then the available power is improved, but the motor operates outside its peak power range reducing efficiency
Solution Approach 1:
The transmission shift schedule is dynamically adjusted based on operating conditions. During EV mode, the shift schedule is modified to keep the motor operating in its peak power range, allowing increased power output when needed. The controller monitors motor speed and transmission gear to selectively apply different shift schedules that optimize power delivery while preserving energy reserves.
Solution Approach 2:
The controller continuously monitors motor speed, transmission gear position, and operating mode to determine when to apply the modified EV mode shift schedule. This feedback mechanism ensures the motor operates within its peak power range by adjusting shift points based on real-time conditions, thereby maintaining both efficiency and power output.
Data Source
AI summary
A vehicle includes and an engine, a motor, a transmission, and a controller. The transmission is configured is to receive power from the engine and the motor. The transmission is also configured to shift between gears based on a shift schedule. The controller is programmed to, in response to only the motor providing power to the transmission, adjust the shift schedule to narrow an operating speed range of the motor such that the motor speed maintains a peak range of an available motor power output.