Hybrid Vehicle Clutch Device with Parallel Locking Elements
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Solution Overview
Problem
Hybrid vehicle drive systems face inefficiencies due to the energy consumption and heat dissipation challenges associated with oil-immersed friction clutches, which require additional systems for oil management and result in splashing losses and friction losses.
Innovation Solution
A drive system with a clutch device featuring a frictional locking element and a positive locking element connected in parallel, allowing for flexible torque transmission and enabling the internal combustion engine to be started and synchronized by the electric motor without a separate starter motor, and allowing the clutch to be designed without an oil bath for reduced energy consumption and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a friction clutch runs in oil to dissipate friction heat, then heat dissipation is improved, but system complexity and energy consumption increase due to oil transportation and storage systems
Solution Approach 1:
The patent extracts the harmful element (oil) from the clutch system by designing a dry friction clutch that operates without oil immersion. The friction heat is dissipated through the clutch housing and surrounding structure rather than through an oil bath, eliminating the need for oil transportation and storage systems.
Solution Approach 2:
The patent replaces the fluid-based heat dissipation system (oil bath) with a solid-based heat dissipation system (clutch housing conduction and convection). The friction heat is transferred directly to the clutch housing which acts as a heat sink, substituting the mechanical oil circulation system with a simpler thermal conduction path.
2Temperature
If a friction clutch runs in oil to dissipate friction heat, then heat dissipation is improved, but energy consumption increases due to splashing losses and oil pump friction losses
Solution Approach 1:
The patent removes the oil medium from the clutch operation, eliminating splashing losses associated with rotating parts moving through oil. The dry friction clutch design extracts the harmful energy losses by operating in air rather than immersed in oil, requiring no oil pump and eliminating all associated friction losses.
3Force
If the friction clutch is designed for full torque transmission, then torque capacity is improved, but the clutch dimensions and system compactness worsen
Solution Approach 1:
The patent segments the torque transmission function between two distinct elements: a frictional locking element for starting and synchronization (handling low torque during transient operations) and a positive locking element for full torque transmission during steady-state operation. This segmentation allows the friction element to be compact while still providing adequate torque capacity for its specific function.
Solution Approach 2:
The frictional locking element is designed to provide partial torque transmission capability - sufficient for starting and synchronization operations but not sized for full continuous torque transmission. The positive locking element supplements this to handle the full torque requirement, allowing the friction element to remain compact.
4Ease of operation
If a separate electric starter motor is used to start the internal combustion engine, then engine starting capability is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent merges the starter motor function with the electric motor that is already part of the hybrid drive system. The electric motor can operate in multiple modes: as a propulsion motor during electric drive, as a starter motor to crank the internal combustion engine, and as a generator during regenerative braking. This combining eliminates the need for a separate starter motor and its associated control systems.
Solution Approach 2:
The electric motor is designed with multi-functionality to serve as both a propulsion device and a starter motor. The clutch device enables the electric motor to universally perform different functions by coupling and decoupling the internal combustion engine from the drive system, allowing the same motor to start the ICE and provide drive torque without requiring separate dedicated components.
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
This solution reduces energy consumption, allows for a more compact design, and eliminates splashing losses, enabling efficient torque transmission and improved system efficiency by utilizing the electric motor for starting the internal combustion engine and transmitting its torque through a positive locking mechanism.
Implementation Method 1
a frictional locking element which permits the transmission of a torque from the electric motor to the internal combustion engine in a flexible manner in terms of rotational speed
Implementation Method 2
a positive locking element which is connected in parallel with respect to the frictional locking element
Data Source
AI summary
A drive system for a hybrid vehicle having an internal combustion engine includes an electric motor and a clutch device which has a frictional locking element and a positive locking element that is connected parallel to the frictional locking element. The clutch device is configured to couple the internal combustion engine into the drive system and to be switched into at least the following states: a) open positive locking element and closed frictional locking element when starting and/or synchronization of the internal combustion engine, b) closed positive locking element and closed frictional locking element or closed positive locking element and open frictional locking element when the internal combustion engine is running and synchronized such that an internal combustion engine drive output action is generated, and c) open positive locking element and open frictional locking element when the internal combustion engine is stopped such that purely electric motor drive of the vehicle is provided.