Two-Way Clutch Power Split Drivetrain for EV Range Extension
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrified vehicles with power split transmissions are limited in providing mechanical torque to wheels, constraining vehicle operation and tractive effort, especially when only the first electric machine can operate as a generator, reducing functionality and range.
Innovation Solution
Incorporating a two-way clutch between the internal combustion engine and planetary carrier in the powertrain, allowing the engine to be prevented from rotating during electric drive modes, enabling four-wheel drive operation in both forward and reverse directions and extending the vehicle's range by leveraging a chemical power source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the first electric machine operates only as a generator, then the power split transmission can provide electric power to the second electric machine, but the vehicle cannot utilize the first electric machine for mechanical torque to wheels, constraining vehicle operation
Solution Approach 1:
The first electric machine is designed to perform multiple functions: it can operate as a generator to provide electric power to the second electric machine, and also as a propulsion motor to provide mechanical torque directly to the wheels. This multi-functionality resolves the contradiction by allowing the same component to serve different purposes based on driving conditions.
Solution Approach 2:
The system dynamically switches the operating mode of the first electric machine between generator and motor modes based on vehicle requirements. The controller selectively engages the first electric machine in different modes, allowing adaptive response to varying driving conditions and extending vehicle operational versatility.
2Power
If the engine rotates continuously to power the first electric machine, then electric power can be provided to the second electric machine, but the vehicle cannot operate in pure electric drive modes, reducing efficiency
Solution Approach 1:
The two-way clutch dynamically changes its engagement state based on operating mode. In pure electric drive modes, the clutch disengages to prevent engine rotation, allowing the vehicle to operate efficiently on electric power alone. In range extension modes, the clutch engages to connect the engine to the power split transmission, enabling electric power generation when needed.
Solution Approach 2:
The two-way clutch extracts the engine from the power flow path during pure electric operation, preventing it from rotating and consuming energy. This separation allows the electric machines to operate independently without engine interference, improving energy efficiency during electric-only modes.
3Device complexity
If the power split transmission drives a single axle, then the transmission structure can be simplified, but the vehicle tractive effort is constrained during some operating conditions
Solution Approach 1:
The first electric machine provides dual functionality: it can power the second electric machine that drives the single axle, or it can directly provide mechanical torque to the wheels. This multi-functionality compensates for the single-axle limitation, allowing the vehicle to achieve adequate tractive effort by selecting the appropriate power path based on driving conditions.
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 enhances driveline functionality, allows four-wheel drive operation in both directions, and extends the driving range of electrified vehicles by utilizing a chemical power source, applicable to both four-wheel and two-wheel drive vehicles.
Implementation Method 1
a two-way clutch positioned between the internal combustion engine and the planetary carrier
Data Source
AI summary
Methods and systems for extending range and functionality of an electrified vehicle are described. In one example, a two-way clutch allows a vehicle to move in a forward or reverse direction under power of an electric machine. The electric machine may be operated as a generator and as a motor.