Switchable Torque Converter Path for Lock-Up Loss Reduction
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Solution Overview
Problem
Existing powertrain systems with torque converters experience inefficiencies during lock-up conditions due to inertial losses and limited rotational speed, which are not effectively addressed by current technologies.
Innovation Solution
A powertrain architecture that allows for a switchable torque path between indirect coupling through a torque converter and direct drive, utilizing a dynamic controllable clutch and an electric friction clutch to seamlessly transition between these paths, bypassing the torque converter when direct drive is desired, and synchronizing its operation with the prime mover's speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the torque converter is locked up during steady-state cruising, then efficiency is improved, but inertial losses occur and rotational speed is limited
Solution Approach 1:
The patent implements a dynamic switching mechanism that allows the torque converter to transition between locked-up and unlocked states based on operating conditions. A control system monitors vehicle speed and load, then actuates a clutch to engage or disengage the lock-up mechanism, enabling the system to adapt between efficiency-oriented locked-up mode and speed-capable unlocked mode.
Solution Approach 2:
The patent changes the operational parameters of the torque converter by introducing a variable lock-up state controlled by a clutch mechanism. The clutch can be engaged to lock the torque converter (changing the slip ratio parameter to zero) or disengaged to allow free rotation (changing the slip ratio parameter to a non-zero value), thereby adjusting the system's rotational speed capability and efficiency characteristics.
2Power
If the torque converter rotates during lock-up, then torque is transferred, but inertial losses occur reducing efficiency
Solution Approach 1:
The patent extracts the inertial loss problem by introducing a clutch mechanism that can completely disconnect the torque converter from the power flow path during lock-up operation. When the clutch is engaged, torque is transferred directly from the transmission output to the input shaft, bypassing the rotating torque converter components and eliminating their inertial losses while maintaining full torque transfer capability.
Solution Approach 2:
The clutch acts as an intermediary element between the transmission output and the torque converter input shaft. When engaged, it provides a direct mechanical connection that mediates torque transfer without requiring the torque converter to rotate, thereby eliminating inertial losses. When disengaged, it allows the torque converter to rotate freely for torque multiplication functions.
3Loss of energy
If a switchable torque path architecture is implemented, then efficiency is improved by eliminating torque converter rotation, but device complexity increases
Solution Approach 1:
The patent merges the lock-up clutch function with the existing torque converter structure, integrating the switching mechanism into the torque converter housing rather than adding a completely separate system. The clutch is positioned within the torque converter assembly and shares mounting structures and control systems with existing components, thereby reducing the overall complexity increase that would result from a fully independent switching architecture.
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 architecture reduces inefficiencies and extends the operational speed range by eliminating torque converter rotation during direct drive, enhancing efficiency and reducing inertial losses, while maintaining flexibility in torque transfer.
Implementation Method 1
A torque converter uses a hydrodynamic circuit to multiply the input torque and transmit the increased torque as an output torque to the input of the driven device
Implementation Method 2
The electric friction clutch includes a first set of friction plates and a second set of friction plates... friction between the two sets of friction plates carries torque
Data Source
AI summary
An architecture for coupling an output member from a prime mover to an input member of a device to be driven. The architecture includes a torque transfer device defining an indirect coupling for transferring torque therethrough, a direct drive connection member providing a direct coupling for transferring torque therethrough, and a dynamically controllable clutch that selectively and rotationally drives either the torque transfer device or the direct drive connection member. The torque transfer device is rotatably disconnected from the dynamically controllable clutch and undriven when the dynamically controllable clutch is driving the direct drive connection member.