Distributed EVT Layout for Compact Hybrid AWD Drivelines
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Solution Overview
Problem
Traditional electrically variable transmissions (EVT) in hybrid electric vehicles (HEVs) are limited to front-wheel drive (FWD) or require additional costly components for all-wheel drive (AWD), lacking a cost-effective and compact solution for achieving AWD capability.
Innovation Solution
A hybrid electric vehicle (HEV) with a distributed electrically variable transmission (EVT) system, where the EVT components are distributed across both the front and rear axles, incorporating a P2 electric machine in the front driveline and a P4 electric machine on the rear axle, eliminating the need for a P3 motor and reducing packaging space and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional EVT components are concentrated in the front driveline, then the transmission structure is compact and simple, but all-wheel drive capability cannot be achieved without additional costly components
Solution Approach 1:
The patent divides the EVT system into separate front and rear driveline modules. The front driveline includes the internal combustion engine, power splitting gear set, and first electric machine, while the rear driveline includes the second electric machine. This segmentation allows independent optimization of each module and enables AWD capability without requiring a completely new centralized transmission design.
Solution Approach 2:
The power splitting gear set in the front driveline serves multiple functions: it provides mechanical power transmission to the front wheels, enables electrical power generation from the first electric machine, and facilitates torque distribution to both front and rear drivelines. This multi-functionality reduces the need for separate dedicated components for each function.
2Adaptability or versatility
If additional components are added to achieve all-wheel drive capability, then four-wheel drive or all-wheel drive capability is achieved, but cost and device complexity increase
Solution Approach 1:
The first electric machine in the front driveline serves dual purposes: it functions as a motor to provide torque to the front wheels and as a generator to produce electrical energy. This self-service capability reduces the need for separate generator components and large battery systems, thereby lowering overall system cost while maintaining AWD functionality.
Solution Approach 2:
The patent combines the power splitting gear set with the first electric machine in the front driveline, integrating mechanical and electrical power transmission functions into a single compact module. This merging eliminates the need for separate mechanical differentials and electrical motor mounts, reducing component count and manufacturing cost.
3Adaptability or versatility
If additional components are added to achieve all-wheel drive capability, then four-wheel drive or all-wheel drive capability is achieved, but weight and packaging space increase
Solution Approach 1:
By segmenting the EVT system into modular front and rear driveline packages, each module can be independently optimized for weight and space. The front module contains heavier components (engine, power splitting gear set) while the rear module contains lighter electric machine components, allowing efficient weight distribution and packaging.
Solution Approach 2:
The first electric machine is positioned concentrically with the power splitting gear set in the front driveline, with the electric machine housed within or adjacent to the gear set housing. This nested arrangement minimizes the overall footprint of the front driveline module, reducing packaging space requirements without compromising AWD capability.
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
The distributed EVT system provides four-wheel-drive (4WD) or all-wheel-drive (AWD) capability while reducing cost, weight, and packaging space compared to conventional EVT AWD solutions.
Implementation Method 1
a power splitting planetary gear set including a carrier coupled for rotation with the input member, a sun gear coupled for rotation with the connecting member, an annulus gear, and a plurality of pinion gears coupled to the carrier and in meshing engagement with the sun gear and the annulus gear
Implementation Method 2
A first electric machine is coupled to the EVT via a connecting member to selectively provide drive torque to the front driveline. A second electric machine is configured to selectively provide drive torque to the rear driveline.
Implementation Method 3
A battery is electrically coupled to the first and second electric machines for powering thereof
Implementation Method 4
wherein the transfer gear arrangement is connected to a final drive to provide drive torque thereto; wherein the final drive includes a differential
Data Source
AI summary
A hybrid electric vehicle (HEV) includes a front driveline configured to drive front wheels, a rear driveline configured to drive rear wheels, and an electrically variable transmission (EVT) including a power splitting gear set. An internal combustion engine is selectively connected to an input member of the EVT to provide drive torque to the front driveline. A first electric machine is coupled to the EVT via a connecting member to selectively provide drive torque to the front driveline. A second electric machine is configured to selectively provide drive torque to the rear driveline. A battery is electrically coupled to the first and second electric machines for powering thereof. The internal combustion engine, the EVT, and the first and second electric machines are configured to provide the HEV with four-wheel drive or all-wheel drive capability.