Driveline Disconnect Clutch Torque Disturbance Control
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Solution Overview
Problem
Hybrid vehicles with driveline disconnect clutches experience torque disturbances during engine starting, leading to increased driveline noise, vibration, and harshness (NVH), which compromise fuel economy and drivability.
Innovation Solution
Opening a closed torque converter clutch during engine start and adjusting the driveline integrated starter/generator (DISG) speed to control torque transfer, reducing driveline torque pulsations and disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the driveline disconnect clutch is closed to provide torque during engine start, then torque transfer capability is improved, but driveline torque disturbance and NVH increase
Solution Approach 1:
The torque converter clutch is opened in advance before the driveline disconnect clutch is closed during engine start. This preliminary action prepares the driveline by disconnecting the torque converter, preventing it from transmitting torque disturbances to the transmission when the disconnect clutch engages. The sequence ensures that the torque converter cannot amplify or transmit the shock loads to the drivetrain components.
Solution Approach 2:
The torque converter clutch acts as an intermediary element between the engine and the transmission. By controlling its state (open or closed), it mediates the torque flow and protects the transmission from torque disturbances. When opened, it isolates the transmission from engine-induced torque pulses, effectively using the clutch as a protective mediator in the powertrain system.
2Power
If the torque converter clutch is closed during engine start, then torque transmission is improved, but driveline wear increases
Solution Approach 1:
The torque converter clutch is opened before engine start to prevent torque disturbances from reaching the transmission. This preliminary disconnection protects driveline components from excessive wear during the high-stress engine starting condition, extending component life while still allowing the vehicle to start properly through alternative torque paths.
3Object-affected harmful factors
If the driveline disconnect clutch is opened to reduce torque disturbance, then NVH is reduced, but torque delivery capability decreases
Solution Approach 1:
The system dynamically adjusts the state of the torque converter clutch based on operating conditions. During engine start, the clutch is opened to reduce NVH, but under normal operating conditions, it can be closed to provide direct torque transmission. This dynamic control allows the system to optimize both NVH performance and torque delivery capability depending on the specific operating scenario.
Solution Approach 2:
The control system changes the operational parameters of the torque converter clutch (open/closed state) in response to different engine operating conditions. By monitoring engine speed, torque demand, and other parameters, the system selectively opens or closes the clutch to balance NVH reduction with adequate torque delivery, adapting to varying drive cycle requirements.
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 approach reduces driveline torque disturbances, improves vehicle drivability, and extends driveline wear life, thereby enhancing overall vehicle performance and fuel efficiency.
Implementation Method 1
a torque converter that includes a torque converter clutch, an impeller that is rotatably coupled to an output shaft of the driveline integrated starter/generator, and a turbine that is rotatably coupled to an input shaft of the transmission
Implementation Method 2
a driveline integrated starter/generator (DISG) coupled to an output shaft of the engine
Data Source
AI summary
Systems and methods for improving operation of a hybrid vehicle are presented. In one example, compensation for a driveline disconnect clutch is provided. The approaches may reduce driveline torque disturbances.