In-Wheel Motor Speed Control to Limit Vehicle Weight Growth
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Solution Overview
Problem
Existing vehicle drive devices that rely on in-wheel motors for propulsion face challenges in efficiently driving vehicles without increasing weight, due to the need for large batteries and high-voltage electrical systems to support motor operation.
Innovation Solution
A vehicle drive device that incorporates a vehicle speed sensor and a controller to manage an in-wheel motor, which generates driving force only when the vehicle reaches a predetermined speed, allowing for the use of smaller motors and reducing overall weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If in-wheel motors are used to drive the vehicle from startup, then sufficient driving force is obtained, but large motors are required which increases vehicle weight
Solution Approach 1:
The patent applies dynamics by making the motor operation conditional rather than continuous. The in-wheel motor is operated dynamically based on real-time vehicle speed detection, switching between on and off states to match actual driving needs, thereby reducing overall motor size while maintaining sufficient driving force when required
Solution Approach 2:
The patent changes the operational parameters of the in-wheel motor by introducing speed-based control thresholds. The motor operates only when vehicle speed exceeds a predetermined threshold, transforming the motor's duty cycle and performance characteristics to allow smaller motor sizing while maintaining adequate driving capability
2Duration of action of moving object
If large capacity battery and high voltage electrical system are used to support motor operation, then sufficient travel performance is obtained, but vehicle weight increases and fuel efficiency reduces
Solution Approach 1:
The patent applies partial action by operating the in-wheel motor only during specific speed conditions rather than continuously. This partial operation reduces the total energy consumption and power requirements, allowing for smaller battery capacity and lower voltage electrical systems while still achieving sufficient travel performance
Solution Approach 2:
The patent changes the operational parameters of the electrical system by introducing speed-based control. The motor operates only when vehicle speed exceeds a predetermined threshold, transforming the system's power consumption profile to allow for reduced battery capacity and voltage requirements
3Productivity
If in-wheel motors are used for startup and acceleration, then driving performance is improved, but the advantage of weight reduction from eliminating drive shafts cannot be obtained sufficiently
Solution Approach 1:
The patent applies dynamics by making the in-wheel motor operation conditional based on vehicle speed. The motor is activated only when speed exceeds a predetermined threshold, creating a dynamic operation pattern that maintains driving performance while significantly reducing motor size and weight
Solution Approach 2:
The patent changes the operational parameters by introducing speed-based control thresholds. The motor operates only during specific speed ranges, transforming the duty cycle and performance characteristics to achieve weight reduction while maintaining adequate driving performance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables efficient vehicle driving using in-wheel motors without the vicious cycle of increased weight and reduced fuel efficiency, by optimizing motor usage based on vehicle speed.
Implementation Method 1
an in-wheel motor that is provided in a wheel of the vehicle and drives the wheel
Implementation Method 2
a vehicle speed sensor that detects a travel speed of the vehicle
Data Source
AI summary
To provide a vehicle drive device capable of efficiently driving a vehicle by using in-wheel motors without falling into the vicious cycle between enhancement of driving via the motors and an increase in vehicle weight. The present invention is a vehicle drive device that uses in-wheel motors to drive a vehicle and includes a vehicle speed sensor that detects the travel speed of a vehicle, in-wheel motors that are provided in wheels of the vehicle and drive the wheels, and a controller that controls the in-wheel motors, in which the controller controls the in-wheel motors so as to generate driving forces when the travel speed of the vehicle detected by the vehicle speed sensor is equal to or more than a predetermined first vehicle speed that is more than zero.