Electric Vehicle Powertrain Layout With Torque-Split Transmission
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Solution Overview
Problem
Existing powertrains for heavy-duty electric vehicles face challenges in balancing packaging and performance, as traditional transmissions adapted for internal combustion engines are not optimized for electric powertrains, leading to inefficiencies and increased costs.
Innovation Solution
A powertrain configuration featuring a transmission with a planetary gearset, additional gearsets, and gear engaging devices that provide torque split and allow for rotational disconnection of gearwheels, reducing load-independent losses and enabling a compact, cost-effective design by locating components on opposite sides of a geometric sectional plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional transmissions adapted for internal combustion engines are used in electric vehicles, then the transmission structure is well-established and reliable, but the packaging efficiency and energy performance are insufficient
Solution Approach 1:
The transmission employs a torque split mechanism that dynamically distributes power through multiple torque paths based on operating conditions. The gear engaging devices can selectively connect or disconnect different torque paths, allowing the transmission to adapt its power flow configuration for optimal energy efficiency while maintaining reliability through proven mechanical components
Solution Approach 2:
The transmission is divided into multiple independent gearsets (planetary gearset, first gearset, second gearset) that can operate semi-independently. This segmentation allows different portions of the powertrain to be optimized for specific functions, improving overall energy efficiency while each segment maintains established reliable design principles
2Reliability
If traditional transmissions adapted for internal combustion engines are used in electric vehicles, then the transmission structure is well-established and reliable, but the packaging efficiency and cost are increased
Solution Approach 1:
Multiple gearsets (planetary gearset, first gearset, second gearset) are merged into a single integrated transmission unit with shared components such as the output shaft and gear engaging devices. This consolidation achieves compact packaging suitable for electric vehicles while maintaining the reliability of each individual gearset through proven design principles
3Loss of energy
If torque split is implemented with multiple torque paths, then energy efficiency is improved by reducing forces on gearwheels, but the transmission complexity increases
Solution Approach 1:
The gear engaging devices serve multiple functions: they can connect or disconnect different torque paths, enable torque split configurations, and provide direct drive connections. This multi-functionality allows the transmission to achieve energy efficiency through torque split while reducing overall device complexity by using the same components for multiple purposes
Data Source
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AI summary
The disclosure relates to a powertrain (100) for a vehicle (200), the powertrain (100) comprising: a transmission (T), a propeller shaft (16') and a differential gear (118), wherein the transmission (T) comprises an output shaft (16) which is drivingly connected or connectable to the propeller shaft (16'), the propeller shaft (16') is drivingly connected to the differential gear (118) and the differential gear (118) is configured to provide a driving torque to a respective half-shaft (119a, 119b) of a drive axle (119) for driving the vehicle (200), the transmission (T) further comprising: an input shaft (5) configured to be drivingly connected to a power unit (110); a planetary gearset (PGT); a first gearset (GS1) and a second gearset (GS2). The disclosure also relates to a vehicle (200).