Electric Tag Axle Control for Hybrid Drivetrain Energy Harvesting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a need for improved control strategies for secondary or tag electric axles in hybrid electric drivetrain systems to optimize power split between internal combustion engines and electric motor generators, particularly for commercial vehicles, to enhance efficiency and energy harvesting capabilities.
Innovation Solution
A method involving a controller that determines the availability of electrical energy and engages/disengages an axle disconnect clutch to transition the axle assembly through various states, such as 6x4 Hi and 6x4 Low, based on vehicle speed, road grade, and energy availability, allowing for efficient power distribution and energy harvesting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an electric tag axle is added to a hybrid electric drivetrain system, then energy harvesting and power split optimization are improved, but device complexity increases
Solution Approach 1:
The electric motor generator is designed to perform multiple functions: it can operate as a motor to drive the tag axle, as a generator to harvest energy during regenerative braking, and as a coupling mechanism between the internal combustion engine and the wheel. This multi-functionality reduces the need for separate components for each function, thereby managing system complexity while achieving energy harvesting capabilities.
Solution Approach 2:
The electric motor generator acts as an intermediary component between the internal combustion engine and the wheel assembly. It mediates the power transmission and enables bidirectional energy flow, allowing the system to harvest energy during deceleration while maintaining simplicity through a single intermediate component rather than multiple separate systems.
2Adaptability or versatility
If the axle assembly transitions between multiple states (6x4 Hi, 6x4 Low, 6x2), then adaptability and power distribution are improved, but control complexity increases
Solution Approach 1:
The drivetrain system employs dynamic state transitions between 6x4 Hi, 6x4 Low, and 6x2 configurations based on real-time operating conditions such as vehicle speed, load, and road grade. The controller dynamically adjusts the engagement state of the electric motor generator and the ratio selector to optimize performance for each driving condition, enabling adaptability through dynamic reconfiguration rather than fixed mechanical settings.
Solution Approach 2:
The system changes operational parameters including the engagement state of the axle disconnect clutch, the ratio selector position (high or low gear ratio), and the operating mode of the electric motor generator (motor, generator, or disconnected). These parameter changes enable transitions between different drivetrain states, providing versatility while managing control complexity through parameter-based switching rather than complex mechanical reconfiguration.
3Force
If high reduction capabilities are achieved using an existing electric motor, then torque ratio is improved, but motor size and efficiency are constrained
Solution Approach 1:
Instead of using a large mechanical reduction gear system to achieve high torque ratios, the patent employs an electric motor generator with electronic control to provide the necessary torque multiplication. The electric motor can deliver high torque at low speeds through electrical control, eliminating the need for complex mechanical reduction gears and reducing overall system size while maintaining efficiency.
Solution Approach 2:
The system achieves variable torque ratios by changing the operating parameters of the electric motor generator, including its rotational speed, torque output, and engagement state. The ratio selector mechanism provides discrete high and low gear ratios, allowing the motor to operate in optimal efficiency ranges while delivering the required torque for different driving conditions, thus achieving high torque ratios without increasing motor size.
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 approach optimizes power split and energy use, improving fuel economy and dynamic performance by enabling the axle assembly to provide traction force and regenerate energy effectively, enhancing overall vehicle efficiency and load-carrying capacity.
Implementation Method 1
an electric motor generator (142)
Implementation Method 2
an axle disconnect clutch (150) is engaged
Data Source
AI summary
A method of controlling an axle assembly includes providing an axle assembly in a first state. A first controller is provided in electrical communication with the axle assembly. The first controller determines if a source of power has an available amount of electrical energy that is within a predetermined range and a predetermined period of time has elapsed. If the available amount of electrical energy is within the predetermined range and the predetermined period of time has elapsed, then electrical energy is transferred from the source of power to an electric motor generator and an axle disconnect clutch is engaged to provide the axle assembly in another state.