Motor Vehicle Power Meter Switching for Stop-Range Torque Display
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Solution Overview
Problem
The display of zero power output in motor vehicles when the drive force and sliding down are balanced, such as at an uphill road, causes discomfort to users due to the consumption of electric power by the traction motor.
Innovation Solution
A display system that includes a power meter and a control unit to display either torque base percentage or drive power base percentage based on vehicle speed, switching between these displays to align with the user's acceleration work.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the power meter displays drive output (multiplication of motor torque and rotation speed) as percentage, then the display accurately reflects the calculated drive power, but the user feels uncomfortable when the vehicle is stopped because the display shows 0% even though the traction motor is consuming electric power to balance sliding down
Solution Approach 1:
The power meter dynamically switches between two display modes based on vehicle speed: when vehicle speed is below a predetermined threshold (vehicle stop range), it displays torque base percentage; otherwise, it displays drive power base percentage. This dynamic adaptation resolves the contradiction by selecting the appropriate display metric according to the vehicle's operational state.
Solution Approach 2:
The display system changes the parameter being displayed based on vehicle speed conditions. At low speeds (vehicle stop range), it displays torque base percentage (percentage of motor torque with respect to rated torque). At higher speeds, it displays drive power base percentage (percentage of drive output with respect to rated output). This parameter switching ensures the display remains meaningful and comfortable for users across different operating conditions.
2Loss of information
If the power meter displays drive output as percentage, then the display shows the output of the traction motor, but it fails to reflect the actual power consumption when the vehicle is stationary and the motor is generating torque to counteract gravitational force
Solution Approach 1:
The system dynamically selects which parameter to display based on vehicle speed. When the vehicle is stopped or moving very slowly (below predetermined speed threshold), the system displays torque base percentage, which accurately reflects the motor's torque output and power consumption even when drive power would be zero. This dynamic selection prevents information loss by showing the relevant metric for the current operational state.
Data Source
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AI summary
It is to provide a display system of a motor vehicle capable of avoiding a user from feeling uncomfortable at a power display for a traction motor. [Solution] There are provided: a traction motor 2 to generate a drive force to thereby drive a motor vehicle 1; a power meter 3 to display an output of the traction motor in percentage; a display control unit 41 to cause the power meter to display percentage of a value to be obtained by dividing a generated motor torque by the traction motor by a rated torque of the traction motor when a vehicle speed of the motor vehicle is in a vehicle stop range of a predetermined vehicle speed or lower, otherwise calculate a drive power by multiplying the generated motor torque by a rotation speed of the traction motor and cause the power meter to display percentage of the calculated drive power with respect to a rated output of the traction motor.