Driveline Disconnect Transfer Case with 48V Motor
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Solution Overview
Problem
Current vehicle driveline systems face challenges in reducing CO2 emissions, as driveline disconnect systems incur high costs and suboptimal losses in 2WD mode, and mild hybridization with 48V electrical motors does not fully utilize the potential for CO2 reduction and adds additional losses due to direct engine connection during regeneration.
Innovation Solution
A vehicle driveline system incorporating a transfer case with a center differential and a shifting sleeve actuator that maintains torque transfer to the rear axle while disconnecting the front axle, reducing drag losses and incorporating a 48V electrical motor for hybrid functions, enabling efficient energy regeneration and additional vehicle functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a driveline disconnect system is implemented to reduce CO2 emissions, then fuel consumption is reduced, but the system cost increases and drag losses are not fully optimized
Solution Approach 1:
The patent extracts the disconnect functionality from a complex clutch-based system and implements it through a simpler transfer case mechanism with a shifting sleeve. The disconnect function is achieved by mechanically disengaging the front axle from the driveline through the transfer case, eliminating the need for expensive clutch assemblies while maintaining effective drag loss reduction.
Solution Approach 2:
The patent employs a cost-effective shifting sleeve mechanism instead of expensive clutch units. The shifting sleeve is a simple, inexpensive component that provides the necessary disconnect function without the high cost associated with traditional clutch-based disconnect systems, thereby reducing overall system cost while maintaining energy efficiency.
2Loss of energy
If a clutch-based disconnect system is used, then the front axle can be disconnected, but high clutch drag occurs in disconnected mode
Solution Approach 1:
The patent removes the clutch component entirely from the disconnect mechanism and replaces it with a direct mechanical disengagement system through the transfer case. This extraction of the clutch eliminates the source of high clutch drag, allowing the front axle to be disconnected with minimal energy loss while maintaining full disconnect functionality.
3Loss of energy
If a 48V electrical motor is installed as B-ISG for mild hybridization, then CO2 emissions are reduced, but additional functionality is limited
Solution Approach 1:
The patent integrates the 48V electrical motor into the transfer case mechanism, enabling it to serve multiple functions: power assistance during acceleration, energy regeneration during deceleration, and potential AWD operation when combined with the disconnect system. This multi-functional integration expands vehicle capabilities beyond what a traditional B-ISG configuration provides, while maintaining CO2 emission reductions.
Data Source
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AI summary
A vehicle driveline system (100) is provided comprising a differential (120) having an input (102), a front output (106) connecting to a front axle (12) and a rear output (104) connecting to a rear axle (14). The vehicle driveline system (100) further comprises an actuator (130) which is configured to control the operation of the differential (120) between a first mode, in which the front output (106) is disconnected from the input (102), and a second mode, in which the front output (106) is connected to the input (102).