Multi-mode engine disconnect clutch for hybrid electric vehicles
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Solution Overview
Problem
Current hybrid electric vehicle powertrains face inefficiencies due to the use of torque converters, which result in fuel economy losses and increased complexity, particularly in parallel hybrid architectures where engine friction and energy recovery are limited.
Innovation Solution
The implementation of a multi-mode engine-disconnect clutch device with a selectable one-way clutch integrated between the engine flexplate and torque converter pump, along with a damper assembly, allows for electronic actuation and control of the clutch to optimize engine connection and disconnection based on various vehicle operations, reducing engine friction and enhancing regenerative energy capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torque converter is used in a hybrid electric vehicle powertrain, then smooth power delivery and engine stall prevention are achieved, but fuel economy deteriorates and system complexity increases
Solution Approach 1:
The patent extracts the torque converter from the powertrain system by implementing an engine disconnect clutch that mechanically decouples the engine from the transmission and torque converter. This allows the engine to be completely disconnected during electric-only operation, eliminating the energy losses associated with torque converter fluid coupling while maintaining the ability to engage the torque converter when needed for smooth power delivery.
Solution Approach 2:
The patent implements a dynamic clutch control system that selectively engages and disengages the engine from the torque converter based on operating conditions. The clutch can transition between engaged and disengaged states, allowing the system to optimize between torque converter benefits (smooth delivery, stall prevention) and fuel economy by disconnecting during electric-only mode.
2Stability of the object's composition
If a torque converter is used in a hybrid electric vehicle powertrain, then smooth power delivery is achieved, but system complexity increases
Solution Approach 1:
The patent extracts the torque converter from the direct engine connection by inserting an engine disconnect clutch between the engine and torque converter. This separation allows the torque converter to be removed or bypassed during electric-only operation, reducing system complexity while maintaining smooth power delivery capability when the engine is engaged.
Solution Approach 2:
The patent segments the powertrain into distinct controllable sections by introducing the engine disconnect clutch as a separate control element. This segmentation allows independent control of engine engagement and torque converter operation, enabling the system to simplify by disconnecting components that are not currently needed while maintaining the option to engage them when required for smooth power delivery.
3Loss of energy
If the engine remains connected during braking, then torque converter operation is maintained, but regenerative energy capture is limited due to engine friction
Solution Approach 1:
The patent extracts the engine from the braking energy recovery path by implementing an engine disconnect clutch that decouples the engine during regenerative braking events. This eliminates engine friction losses that would otherwise oppose the retarding torque, maximizing the energy available for regenerative capture while maintaining torque converter operation through the clutch's torque transmission capability.
Solution Approach 2:
The patent implements dynamic clutch control that selectively disengages the engine during braking events to eliminate friction losses, while maintaining the torque converter connection for smooth power delivery. The system dynamically transitions between engine-connected and engine-disconnected states based on whether regenerative braking is occurring, optimizing energy recovery without sacrificing drivability.
Data Source
AI summary
Presented are engine-disconnect clutches with attendant control logic, methods for making/operating such disconnect clutches, and hybrid electric vehicles (HEV) equipped with an engine that is coupled to/decoupled from a transmission and electric motor via a disconnect clutch. A representative method for controlling an HEV powertrain includes receiving an HEV powertrain operation command, then determining a clutch mode of a multi-mode clutch device to execute the HEV powertrain operation. This multi-mode clutch device is operable in: a lock-lock mode, in which the clutch device transmits torque to and from the engine; a free-free mode, in which the clutch device disconnects the engine's output member from the transmission's input member, preventing torque transmission to and from the engine; a lock-free mode, in which the clutch device transmits torque from but not to the engine; and, a free-lock mode, in which the clutch device transmits torque to but not from the engine.