Hybrid In-Wheel and Body-Side Motor Control for Vehicle Weight Reduction
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Solution Overview
Problem
Hybrid drive vehicles using in-wheel motors face a vicious cycle of increased weight and reduced fuel efficiency due to the need for large capacity batteries and high voltage systems to support motor-driven travel, leading to weight gain and decreased performance.
Innovation Solution
A vehicle drive device utilizing both in-wheel motors and body-side motors, where the controller manages power distribution based on driver input, using the body-side motor for low power requests and both motors for higher power needs, allowing for smaller, lighter in-wheel motors and omitting heavy deceleration mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If in-wheel motors are used to drive the vehicle, then the driving force is improved, but the vehicle weight increases due to large capacity batteries and high voltage systems
Solution Approach 1:
The drive system is segmented into two independent motor units: body-side motors that drive the vehicle body, and in-wheel motors that drive the wheels. This segmentation allows each motor to be optimized for its specific function, with the in-wheel motor being smaller and lighter since it only needs to overcome rolling resistance and provide steering torque, not the full driving force.
Solution Approach 2:
The control system dynamically adjusts the operating mode between body-side motor drive and in-wheel motor drive based on vehicle conditions. The in-wheel motor operates independently to provide wheel-driven force during light-load conditions, reducing the overall power requirements and allowing for lighter battery and electrical systems.
2Power
If in-wheel motors generate driving forces for all power requests, then sufficient power output is achieved, but the in-wheel motor size and weight increase
Solution Approach 1:
The power delivery is segmented between two motor systems. The body-side motor handles high-power demands while the in-wheel motor handles low-power wheel-driven operations. This segmentation allows the in-wheel motor to be much smaller and lighter than a conventional motor that would need to provide all driving force.
Solution Approach 2:
The in-wheel motor performs only partial driving function - specifically wheel-driven operations for light-load conditions. By accepting that it doesn't provide excessive power capacity, the in-wheel motor can be minimized in size and weight while still achieving sufficient overall vehicle performance through coordination with the body-side motor.
3Duration of action of moving object
If large capacity batteries and high voltage systems are used to support motor-driven travel, then sufficient travel performance is achieved, but fuel efficiency decreases
Solution Approach 1:
The system dynamically switches between body-side motor drive and in-wheel motor drive modes based on power requirements. During light-load conditions, the in-wheel motor provides efficient wheel-driven operation with minimal energy consumption. This dynamic operation allows sufficient travel performance with a smaller, more fuel-efficient electrical system.
Solution Approach 2:
The control system changes operational parameters by selecting different drive modes. The in-wheel motor operates at optimized low-power parameters for wheel-driven operations, while the body-side motor handles high-power demands. This parameter optimization reduces overall energy consumption and improves fuel efficiency while maintaining sufficient travel 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 configuration enables efficient vehicle driving with in-wheel motors without the weight and efficiency penalties, using induction and permanent magnet motors to optimize torque and power delivery.
Implementation Method 1
the in-wheel motor is an induction motor
Implementation Method 2
using induction and permanent magnet motors to optimize torque and power delivery
Data Source
AI summary
A vehicle drive device uses in-wheel motors to drive a vehicle and includes in-wheel motors that are provided in wheels of a vehicle and drive the wheels, a body side motor that is provided in a body of the vehicle and drives the wheels, and a controller that controls the in-wheel motors and the body side motor based on requested output power of a driver, in which the controller causes the body side motor to generate a driving force and the in-wheel motors not to generate driving forces when the requested output power of the driver is less than predetermined output power and the controller causes the body side motor and the in-wheel motors to generate driving forces when the requested output power of the driver is equal to or more than the predetermined output power.