Hydrodynamic Torque Converter with Integrated Engine Disconnect
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current hybrid electric vehicle powertrains face inefficiencies due to torque converter slip, leading to reduced fuel economy and increased emissions, particularly during engine 'Stop & Start' and regenerative braking modes, where engine disconnect mechanisms are not adequately responsive or effective.
Innovation Solution
Integration of a modular torque converter assembly with a hydraulically actuable engine disconnect device within the torque converter's fluid volume, featuring a friction clutch to lock the impeller and turbine shells, and an optional one-way clutch for positive torque transmission, allowing for seamless engine disconnection and reconnection to minimize energy loss and enhance fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a traditional torque converter is used in hybrid electric vehicle powertrains, then the vehicle can operate in engine-only, motor-only, and combined modes, but torque converter slip causes energy losses and reduced fuel economy during engine Stop & Start and regenerative braking modes
Solution Approach 1:
The patent combines the engine disconnect clutch and torque converter clutch into a single integrated device within the torque converter assembly. The engine disconnect clutch is positioned between the impeller and pump cover, allowing it to directly disconnect the engine from the torque converter without requiring a separate disconnect mechanism. This integration eliminates energy losses by enabling complete engine disconnection during Stop & Start and regenerative braking modes while maintaining compact packaging.
Solution Approach 2:
The patent extracts the engine disconnect function from the traditional torque converter structure by introducing a separate engine disconnect clutch mechanism. This clutch can be independently engaged or disengaged to completely separate the engine from the torque converter, preventing parasitic drag and energy losses during motor-only operation. The extracted disconnect function is then integrated into the existing torque converter assembly to maintain space efficiency.
2Productivity
If an engine disconnect device is added to the torque converter, then fuel economy improves during Stop & Start modes, but the device complexity and packaging space requirements increase
Solution Approach 1:
The patent merges the engine disconnect clutch with the torque converter clutch housing and control systems. Both clutches share common hydraulic actuators, control logic, and mounting structures within the torque converter assembly. This integration reduces device complexity by eliminating separate control systems and reducing the number of individual components, while still providing complete engine disconnect capability for improved fuel economy.
Solution Approach 2:
The integrated clutch device performs multiple functions: it acts as both an engine disconnect clutch (separating the engine from the torque converter) and a torque converter clutch (locking the impeller to the turbine). The single device can operate in different modes depending on engagement state, providing both engine disconnection for Stop & Start operation and torque multiplication during acceleration, thereby reducing overall system complexity.
3Loss of energy
If a friction clutch is used to disconnect the engine, then energy losses are reduced, but the response time for transitioning into coasting and motor-only modes may be limited
Solution Approach 1:
The patent employs hydraulically actuated clutches for both engine disconnect and torque converter clutch functions. Hydraulic actuators provide rapid engagement and disengagement through fluid pressure, enabling fast transition into and out of engine disconnect modes. The hydraulic system can quickly build and release pressure to actuate the clutch plates, achieving response times suitable for dynamic Stop & Start operation while minimizing energy losses during the transition.
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 simplifies engine disconnect operations, reduces energy losses, improves fuel economy, and decreases emissions by enabling faster transitions into coasting and motor-only modes with minimal additional cost and complexity, while minimizing packaging space.
Implementation Method 1
featuring a friction clutch to lock the impeller and turbine shells
Implementation Method 2
hydraulically actuable engine disconnect device
Implementation Method 3
A hydraulic pump modulates fluid pressure within the torque converter housing to regulate the transfer of rotational energy from the impeller to the turbine
Data Source
AI summary
Presented are torque converters with integrated engine disconnect devices, methods for making/using such torque converters, and electric-drive vehicles equipped with such torque converters. A torque converter (TC) assembly includes a TC housing that drivingly connects to an engine output member. A TC output member projects from the TC housing and drivingly connects to a transmission input member. A turbine with a bladed turbine shell is mounted on the TC output member and rotatable within the TC's internal fluid chamber. An impeller with a bladed impeller shell is juxtaposed with the turbine and rotatable within the fluid chamber. An engine disconnect device, which is disposed within the fluid chamber between the impeller shell and TC housing, drivingly couples the impeller to and, when desired, drivingly decouples the impeller from the TC housing and engine output member to thereby transfer torque and prevent torque transfer, respectively, between the engine and transmission.