Damper Assemblies for Engine Disconnect Clutches
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Solution Overview
Problem
Current motor vehicle powertrains with internal combustion engines and torque converters experience torque-related vibrations and efficiency losses due to slip between the engine and transmission, leading to increased fuel consumption and noise, vibration, and harshness (NVH) issues.
Innovation Solution
A damper assembly with a positive-engagement selectable one-way clutch is introduced between the engine crankshaft and torque converter pump, featuring a tuned-spring damper assembly and a selector plate to selectively engage and disengage the clutch, reducing torque swings and minimizing packaging size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a torque converter is used to connect the engine to the transmission, then smooth power delivery and vehicle propulsion are improved, but torque-related vibrations and slip between engine and transmission increase leading to fuel consumption losses and NVH issues
Solution Approach 1:
A disconnect clutch is introduced as an intermediary device between the engine and torque converter. This clutch can selectively engage or disengage the mechanical connection, allowing the system to operate in either torque converter mode (for smooth operation) or direct mechanical connection mode (for fuel efficiency), thus resolving the contradiction between smooth power delivery and fuel consumption
2Loss of energy
If a disconnect clutch is introduced between the engine and torque converter, then fuel efficiency is improved by reducing slip, but device complexity increases
Solution Approach 1:
The disconnect clutch is merged with the existing torque converter assembly, sharing common housing, mounting structures, and control systems. This integration approach adds the disconnect functionality while minimizing the increase in overall device complexity, as the new components are combined with rather than added to the existing torque converter structure
3Object-affected harmful factors
If a traditional damper assembly is used to reduce torque swings, then vibration and NVH are improved, but the size and packaging space of the damper assembly increases
Solution Approach 1:
The damper assembly is designed with a nested structure where damping components are positioned within the existing torque converter housing and connect to internal rotating elements. This nesting approach allows the damper to reduce torque swings and vibrations while occupying minimal additional space within the compact torque converter assembly
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 diminishes torque-related vibrations and NVH, enhances fuel efficiency by reducing slip, and minimizes the size of the damper assembly, effectively addressing the challenges of torque reversals and transmission efficiency in both manual and automatic transmission architectures.
Implementation Method 1
Spring elements, which may be in the nature of helical, leaf, torsional, or other spring types, mate the damper plate with the flex plate such that the damper and pocket plates are movably attached to and spring-biased with the flex plate
Data Source
AI summary
Disclosed are damper assemblies for engine disconnect devices, methods for making such damper assemblies, and motor vehicles with a disconnect device for coupling/decoupling an engine with a torque converter (TC). A disconnect clutch for selectively connecting an engine with a TC includes a pocket plate that movably mounts to the TC. The pocket plate includes pockets movably seating therein engaging elements that engage input structure of the TC and thereby lock the pocket plate to the TC. A selector plate moves between engaged and disengaged positions such that the engaging elements shift into and out of engagement with the TC input structure, respectively. A flex plate is attached to the engine's output shaft for common rotation therewith. A damper plate is attached to the pocket plate for common rotation therewith. Spring elements mate the damper and flex plates such that the damper plate is movably attached to the flex plate.