Wedge-Type Selectable One-Way Clutches for Engine Disconnect
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current hybrid electric vehicle powertrains face challenges in maximizing regeneration energy and reducing rotational backlash, noise, and fuel consumption due to the inefficiencies in torque transfer between internal combustion engines and electric motors, particularly in transient operating modes.
Innovation Solution
The implementation of wedge-type selectable one-way clutches (SOWCs) that selectively disconnect the engine from the torque converter and traction motor, allowing for efficient regeneration and minimizing rotational backlash by actively engaging and disengaging torque transfer through a wedge plate mechanism, which is controlled by hydraulic pressure or electronic solenoids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine is continuously connected to the torque converter and transmission, then torque transfer is maintained for vehicle propulsion, but rotational backlash and noise increase, and regeneration energy is reduced
Solution Approach 1:
The patent employs a selectable one-way clutch that dynamically transitions between engaged and disengaged states based on operating conditions. During regenerative braking, the clutch disengages to eliminate rotational backlash and noise while enabling energy recovery. During propulsion, the clutch engages to maintain torque transfer. This dynamic state change resolves the contradiction by adapting the connection status to operational requirements.
Solution Approach 2:
The one-way clutch automatically selects the appropriate operating mode (engaged or disengaged) based on the direction of torque flow and rotational speed relationships between the engine, torque converter, and transmission. The device self-regulates without external control, enabling automatic engine disconnect during regeneration and automatic reconnection during propulsion, thus resolving the contradiction between energy recovery and torque transfer.
2Use of energy by moving object
If the engine is disconnected from the torque converter during coasting and motor-only modes, then fuel consumption is reduced and emissions are lowered, but torque transfer capability is lost
Solution Approach 1:
The selectable one-way clutch provides dynamic control over engine-disconnect status, transitioning between engaged and disengaged states based on powertrain operating mode. During coasting and motor-only modes, the clutch disengages to eliminate parasitic fuel consumption while preserving the ability to rapidly re-engage when torque transfer is needed. This resolves the contradiction by making torque transfer capability available only when required.
Solution Approach 2:
The one-way clutch automatically determines when to disconnect the engine based on rotational speed relationships and torque flow direction. During regenerative braking or coasting, the clutch self-disengages to eliminate fuel consumption. During propulsion or when torque transfer is needed, the clutch self-reengages. This automatic self-regulation resolves the contradiction between fuel economy and torque transfer capability.
3Loss of energy
If a selectable one-way clutch is implemented for engine disconnect, then regeneration energy is maximized and NVH performance is improved, but device complexity increases
Solution Approach 1:
The selectable one-way clutch acts as an intermediary device between the engine and the torque converter-transmission system. It provides automatic engagement/disengagement based on operating conditions, maximizing regeneration energy and improving NVH performance. The clutch's automatic operation and integration into the existing powertrain architecture minimize the increase in device complexity while achieving the desired performance benefits.
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 fuel economy, reduces emissions, and improves noise, vibration, and harshness (NVH) performance while minimizing packaging space and costs, enabling faster engine disconnect response times during coasting and motor-only modes.
Implementation Method 1
the ramps frictionally wedge between the ID and OD surfaces; the wedged ramps transfer torque between the inner and outer races
Implementation Method 2
A hydraulic piston is selectively actuable, e.g., via a vehicle's torque converter charge pressure, to move between deactivated and activated states
Implementation Method 3
An electronic solenoid may alternatively be used in place of the hydraulic piston to selectively position the wedge plate
Data Source
AI summary
Presented are wedge-type engine disconnect devices, methods for making/using such disconnect devices, and motor vehicles equipped with such disconnect devices. An engine disconnect device includes an outer race that attaches to a torque converter's pump cover. The outer race's inner diameter (ID) surface has circumferentially spaced grooves. An inner race is concentrically aligned within the outer race and attaches to an engine's output shaft. The inner race's outer diameter (OD) surface has circumferentially spaced pockets. A wedge plate interposed between the inner and outer races has multiple circumferentially spaced ramps. Each ramp slidably mounts within one groove and one pocket. The wedge plate moves between an engaged position, whereat the ramps wedge between the ID and OD surfaces to thereby transfer torque between the inner and outer races, and a disengaged position, whereat the ramps unwedge to thereby free the inner race to rotate with respect to the outer race.