Clutch Slip Adjustment for Powertrain NVH Control
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Solution Overview
Problem
Existing methods for controlling noise, vibration, and harshness (NVH) effects in vehicle powertrains are inaccurate due to not accounting for all contributors and vehicle aging, leading to either unacceptable NVH levels or excessive fuel consumption.
Innovation Solution
A method and system that adjust the slip of a clutch in a powertrain based on real-time sensing of transmission shaft parameters such as acceleration, speed, and torque, using a controller to maintain a desired NVH level by referencing databases for target slip settings, ensuring closed-loop control and adaptation to operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If clutch slip is increased to reduce NVH effects, then noise, vibration, and harshness are reduced, but fuel consumption increases
Solution Approach 1:
The clutch slip is dynamically adjusted based on real-time sensed parameters (acceleration, speed, torque) rather than being fixed. The controller continuously modifies the target clutch slip to optimize the balance between NVH reduction and fuel efficiency under varying operating conditions.
Solution Approach 2:
A closed-loop control system is implemented where the controller senses transmission shaft parameters, compares them against desired NVH levels, and adjusts clutch slip accordingly. This feedback mechanism prevents over-adjustment and ensures optimal performance.
Solution Approach 3:
The system changes the clutch slip parameter dynamically based on sensed operating conditions. By adjusting this key parameter in real-time, the system optimizes the hydrodynamic coupling between engine and transmission to reduce NVH effects while minimizing fuel consumption penalties.
2Ease of operation
If fixed tables of clutch slip are used based on operating state, then NVH control is simplified, but accuracy deteriorates due to not accounting for all contributors and vehicle aging
Solution Approach 1:
The system uses real-time sensing of transmission shaft parameters to automatically determine the optimal clutch slip without requiring external expert evaluation or complex lookup tables. The controller self-adjusts based on actual measured conditions, adapting to vehicle aging and varying operating states.
Solution Approach 2:
The patent replaces the mechanical/expert-based table lookup approach with an electronic control system that uses sensors and real-time computation. This substitution enables more precise and adaptive NVH control by directly measuring transmission shaft parameters and adjusting clutch slip accordingly.
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 effectively reduces NVH effects while optimizing energy efficiency by dynamically adjusting clutch slip based on sensed parameters, providing a robust and adaptive solution that accounts for various operating conditions and prevents over-adjustment.
Implementation Method 1
Operation of the bypass clutch at a high slip provides a large hydrodynamic coupling between the engine and the transmission which dampens driveline disturbances caused by torque disturbances from the engine
Data Source
AI summary
A vehicle powertrain includes a transmission and a clutch. The slip of the clutch is adjusted to a target where a magnitude of a sensed parameter of a shaft of the transmission corresponds to a desired noise, vibration, and harshness (NVH) level in the powertrain. The sensed parameter of the transmission shaft may be one of acceleration, speed, and torque of the transmission shaft. The transmission shaft may be one of the input shaft and output shaft of the transmission.