Engine Flexplate One-Way Clutch for Torque Converter
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Solution Overview
Problem
Conventional torque converters in motor vehicles experience significant slip between the engine and transmission, leading to inefficiencies and reduced fuel economy, particularly in hybrid and electric vehicle modes, where engine disconnect mechanisms are not effectively managed.
Innovation Solution
Integration of a passive or selectable one-way clutch mechanism within the engine flexplate assembly, operatively coupling and decoupling the engine from a hydrokinetic torque converter, allowing for automatic or selective disconnection of the crankshaft from the torque converter main shaft to prevent inadvertent engine stall and optimize torque transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional torque converter is used to transfer torque from engine to transmission, then the vehicle can operate smoothly during coasting and idle conditions, but significant slip occurs between engine and transmission leading to energy losses and reduced fuel economy
Solution Approach 1:
The patent applies a one-way clutch mechanism that dynamically changes the torque transfer characteristics of the torque converter. The clutch allows free rotation in one direction (reducing slip and energy loss during coasting) while preventing reverse rotation (maintaining smooth operation during idle). This dynamic behavior resolves the contradiction by adapting the torque converter's operation to different driving conditions automatically.
Solution Approach 2:
The one-way clutch acts as an intermediary element between the engine and transmission, mediating the torque transfer. It selectively engages or disengages based on rotation direction, allowing the system to achieve both reduced energy loss and smooth operation by introducing this intermediate control mechanism into the torque path.
2Loss of energy
If engine disconnect mechanisms are implemented to reduce slip and improve fuel economy, then energy efficiency increases, but the device complexity and packaging space requirements increase
Solution Approach 1:
The one-way clutch mechanism is merged with the existing torque converter assembly, integrating the disconnect function into the conventional torque converter design. This combination approach reduces overall system complexity by eliminating the need for separate disconnect mechanisms and reduces packaging space by utilizing the existing torque converter housing and component layout.
3Productivity
If a one-way clutch mechanism is integrated into the torque converter, then engine disconnect capabilities are enhanced during coasting and EV modes, but the manufacturing cost and assembly complexity increase
Solution Approach 1:
The one-way clutch mechanism is designed to operate automatically based on rotation direction without requiring external control systems or complex actuation mechanisms. This self-service approach enhances engine disconnect capability during coasting and EV modes while minimizing manufacturing and assembly complexity, as the clutch engages and disengages autonomously based on the natural rotation direction of the torque converter.
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 enhances engine disconnect capabilities during coasting and electric vehicle modes, improving fuel economy and extending electric vehicle range with minimal additional cost and powertrain packaging space.
Implementation Method 1
The disconnect device is configured to allow the outer race to overrun the inner race when the outer race rotates in a first rotational direction. The disconnect device is configured to prevent the outer race from rotating relative to the inner race when the outer race rotates in a second rotational direction opposite the first rotational direction.
Data Source
AI summary
Disclosed are engine flexplates with integrated engine disconnects, methods for making and for using such flexplates, and motor vehicles with an engine flexplate having an integrated engine disconnect device. An engine flexplate assembly is disclosed for operatively coupling an engine to a hydrokinetic torque converter. The flexplate assembly includes a disk-shaped body with a central hub that rigidly attaches on the fore side thereof to the engine output shaft for common rotation therewith. A disconnect device, which is positioned on the aft side of the disk-shaped body, includes concentric inner and outer races. The outer race is rigidly attached to the disk-shaped body for common rotation therewith. The inner race rigidly attaches to the front cover of the TC housing for common rotation therewith. The disconnect device operatively disconnects the engine output shaft from the TC housing front cover when a torque transmitted therebetween reverses direction.