Multi-Ratio EDM Neutral Mode Using Open Clutch Disconnect
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Solution Overview
Problem
Current electric drive module configurations in all-wheel drive vehicles incur additional cost, mass, and complexity due to the incorporation of wheel end disconnect systems, necessitating a more efficient method to disconnect one drive module without these systems.
Innovation Solution
A controller-operated system that commands a first electric drive module to provide 100% drive torque while disconnecting the second drive module by positioning its clutches to an open state, utilizing a selectable one-way clutch and friction clutch configuration, to achieve a neutral drive mode without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wheel end disconnect systems are incorporated to disconnect an EDM from driveline, then the ability to reduce battery usage and component wear is improved, but additional cost, mass and complexity are added
Solution Approach 1:
The patent extracts the disconnect function from complex mechanical wheel end disconnect systems and implements it through software control of existing clutch mechanisms in the gearbox, eliminating the need for additional disconnect hardware while maintaining the ability to isolate the unpowered EDM from the driveline
Solution Approach 2:
The patent uses the existing multi-ratio gearbox and its clutches as an intermediary mechanism to achieve disconnection of the unpowered EDM, rather than implementing direct wheel end disconnect systems. The clutch acts as a mediator that can engage or disengage torque transmission between the motor and driveline
2Use of energy by moving object
If wheel end disconnect systems are incorporated to disconnect an EDM from driveline, then the ability to reduce battery usage and component wear is improved, but additional cost and mass are added
Solution Approach 1:
The patent removes the need for heavy mechanical disconnect systems by implementing disconnection through software-controlled clutch mechanisms that are already present in the multi-ratio gearbox, thereby reducing mass while maintaining energy efficiency benefits
Solution Approach 2:
The existing multi-ratio gearbox is designed to serve multiple functions: providing different gear ratios for various driving conditions and enabling disconnection of the unpowered EDM through its clutch mechanisms, eliminating the need for separate disconnect hardware
3Adaptability or versatility
If dual EDM configuration is used for all-wheel drive, then the ability to deliver torque to both axles is improved, but the cost, mass and complexity of the system increases
Solution Approach 1:
The patent implements dynamic operation of the dual EDM system by enabling the controller to selectively power one or both motors based on driving conditions, and by using the multi-ratio gearbox to dynamically change the connection state of each motor to the driveline, optimizing system complexity for each operating mode
Data Source
AI summary
An electrified powertrain for an electrified vehicle includes a first electric drive module (EDM), a second EDM and a controller. The first EDM includes a first electric motor. A first gearbox transfers first drive torque from the first EDM to drive first drive wheels. The second EDM includes a second electric motor. A second gearbox transfers second drive torque from the second EDM to drive second drive wheels. The second gearbox has first and second clutches that provide two distinct gear ratios. The controller operates the electrified powertrain in (i) a normal drive mode wherein drive torque is commanded from the first and second electric motors, and a (ii) neutral drive mode wherein the clutches are commanded to an open position whereby the second drive torque is disconnected from the second drive wheels and drive torque is commanded from only the first EDM.