Modular Rear Drive Unit Hybrid Powertrain Adaptation
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Solution Overview
Problem
Hybrid powertrains for vehicles require additional components like planetary gear sets, brakes, and clutches, increasing vehicle cost and packaging space, while existing solutions for adapting conventional rear-wheel drive powertrains to hybrid systems are complex and costly.
Innovation Solution
A modular rear drive unit with a rear differential and electric motor-generator connected via a gearing arrangement, allowing for adaptation of conventional rear-wheel drive powertrains to hybrid systems with reduced complexity and cost, enabling efficient torque transfer and control through a controller-operated motor-generator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional components like planetary gear sets, brakes, and clutches are added to enable hybrid functionality, then hybrid operation modes are achieved, but vehicle cost and packaging space requirements increase
Solution Approach 1:
The patent combines the motor-generator, rear differential, and gearing arrangement into a single integrated modular rear drive unit. This merging of previously separate components into one unified module reduces the overall number of discrete parts, simplifies installation, and maintains hybrid functionality while addressing the complexity issue.
Solution Approach 2:
The motor-generator serves multiple functions: it can operate as a motor to provide driving torque to the rear wheels, as a generator during regenerative braking, and integrates with the rear differential to enable hybrid operation modes. This multi-functionality reduces the need for separate dedicated components.
2Adaptability or versatility
If additional components like planetary gear sets, brakes, and clutches are added to enable hybrid functionality, then hybrid operation modes are achieved, but packaging space requirements increase
Solution Approach 1:
The motor-generator is positioned at least partially rearward of the rear half shafts, with its axis of rotation generally parallel to the driveshaft. The gearing arrangement is integrated within the modular unit, allowing components to be nested or closely packed together. This spatial arrangement optimizes packaging efficiency while maintaining all necessary hybrid functionality.
3Adaptability or versatility
If a complete redesign of the powertrain layout is performed to adapt conventional rear-wheel drive to hybrid systems, then hybrid functionality is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The rear drive unit is designed as a separate, self-contained module that can be manufactured independently and then installed as a unit in the vehicle. This segmentation allows for specialized manufacturing of the hybrid module without requiring complete redesign of the entire powertrain system, thereby reducing manufacturing complexity and cost.
Solution Approach 2:
The modular rear drive unit acts as an intermediary component that bridges conventional rear-wheel drive architecture and hybrid system requirements. It interfaces with existing vehicle components like the driveshaft and rear wheels while incorporating hybrid-specific elements, allowing integration without complete system redesign.
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 solution enables efficient hybrid functionality with reduced production costs and complexity, allowing for a wide range of applications and maintaining the existing powertrain layout, thus improving fuel economy and reducing packaging space requirements.
Implementation Method 1
A second motor-generator is drivingly connected to the rear differential and is positioned at least partially rearward of the rear half shafts. The second motor-generator has a motor shaft with an axis of rotation generally parallel with the driveshaft. A controller is operatively connected to the second motor-generator and is operable to control the second motor-generator to function as a motor that provides driving torque to the rear half shafts through the rear differential.
Implementation Method 2
A gearing arrangement is configured to multiple torque from the second motor-generator to the rear half shafts.
Data Source
AI summary
A powertrain includes an engine that has a crankshaft. A first motor-generator is drivingly connected to the crankshaft via an endless rotatable device. The powertrain includes a transmission that has a transmission input member driven by the crankshaft and a transmission output member. A front differential is operatively connected with front half shafts. A transfer case is configured to distribute torque of the transmission output member to the front differential and to a driveshaft. A rear differential is configured to transfer torque from the driveshaft to rear half shafts. A second motor-generator is drivingly connected to the rear differential. A gearing arrangement is configured to multiply torque from the second motor-generator to the rear half shafts. A controller controls the second motor-generator to function as a motor that provides torque to the rear wheels through the rear differential. A modular rear drive unit operatively connects to the vehicle body.