Transmission Launch Device Slip Control for Driveline Torsional Vibration
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Solution Overview
Problem
Modern automobile transmissions face disturbances from high driveline torsional vibrations due to cylinder deactivation in variable displacement engines and aggressive lock-up strategies, leading to objectionable noise, vibration, and harshness (NVH), which current systems fail to address effectively without wasting fuel.
Innovation Solution
A computationally thrifty method using a controller to detect and reduce these disturbances by measuring transmission speeds, applying a low-resolution discrete Fourier transform, and controlling launch device slip in real-time, allowing for fuel-efficient calibrations that intercept vibrations before they affect occupants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If aggressive lock-up strategies are used to improve fuel efficiency, then fuel economy is improved, but high driveline torsional vibrations and NVH disturbances occur
Solution Approach 1:
The patent implements a feedback control system where a sensor detects driveline torsional vibrations and sends signals to a controller, which then adjusts the lock-up clutch slip to reduce the vibrations. This closed-loop feedback enables the system to maintain aggressive lock-up strategies for fuel efficiency while actively suppressing NVH disturbances when they occur.
Solution Approach 2:
The system dynamically adjusts the lock-up clutch slip based on real-time vibration detection. Rather than maintaining a fixed lock-up state, the controller modulates the clutch slip to actively counteract detected torsional vibrations, allowing the system to adapt between fuel-efficient locked operation and vibration-mitigated slipped operation.
2Object-affected harmful factors
If conservative calibrations are used to prevent NVH, then NVH disturbances are reduced, but fuel efficiency deteriorates
Solution Approach 1:
The feedback control system allows the transmission to operate with aggressive, fuel-efficient conservative calibrations while actively detecting and suppressing NVH disturbances. The sensor-controller-clutch loop enables the system to maintain conservative lock-up strategies most of the time but intervene when vibrations occur, rather than permanently sacrificing fuel efficiency.
Solution Approach 2:
The system uses its own operational data (vibration levels detected by the sensor) to self-regulate and prevent NVH disturbances. The controller monitors the driveline conditions and autonomously adjusts the lock-up clutch to maintain both fuel efficiency and comfort, making the system self-correcting rather than requiring external intervention or conservative default settings.
3Loss of time
If real-time vibration detection is implemented, then disturbances are detected early, but computational complexity increases
Solution Approach 1:
The patent extracts only the essential vibration detection functionality needed for real-time control, using a sensor to detect driveline torsional vibrations and a controller to process this information. By focusing on detecting only the specific vibration frequencies related to cylinder deactivation and lock-up clutch operation, the system achieves real-time detection without requiring complex full-spectrum vibration analysis.
Solution Approach 2:
The real-time detection system is integrated into the existing feedback control loop, where vibration detection triggers automatic adjustment of the lock-up clutch. This integration allows the detection and control functions to work together efficiently, reducing the computational burden by immediately acting on detected vibrations rather than requiring separate complex analysis and decision-making processes.
Data Source
AI summary
The present disclosure provides systems and methods to detect and reduce any high driveline torsional levels, such as due to the cylinder deactivation in variable displacement system engines or aggressive lock-up strategies for fuel efficiency, in automobile transmissions. The present disclosure utilizes a controller in an automobile to operate a computationally thrifty method for quickly detecting noise and vibration disturbances in the transmission. This quick detection enables fuel economic calibrations that aggressively reduce the disturbances by controlling slip in a launch device of the transmission. As problem disturbances arise, they are detected before occupants notice objectionable behavior. Once detected, the disturbances are reduced, such as by increasing launch device slip, which effectively intercepts the objectionable disturbances before they are transferred through the entire drivetrain. The present disclosure can also apply to launch devices in Dual Clutch Transmissions and Electronically-controlled Manual Transmissions.