Powertrain Controller NVH Map for Damper Clutch Resonance
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Solution Overview
Problem
Conventional powertrain systems, including automatic transmissions and Continuously Variable Transmissions (CVTs), face challenges in managing Noise Vibration Harshness (NVH) characteristics, particularly during engine operation, leading to deteriorated noise and vibration issues that affect vehicle comfort and marketability.
Innovation Solution
A powertrain control method that utilizes an NVH characteristic map, calibrated based on engine operating points and environmental factors, to determine whether to release the lock-up state of the damper clutch or increase engine torque, and to control shifting and gear ratio changes, thereby minimizing NVH issues and enhancing vehicle comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the damper clutch is locked-up to enhance fuel economy, then fuel efficiency is improved, but NVH characteristics deteriorate due to resonance area operation
Solution Approach 1:
The controller dynamically changes the operating parameters of the damper clutch by transitioning between locked-up and released states based on the detected engine operating point. When the engine operating point enters a resonance area identified in the NVH characteristic map, the controller releases the damper clutch to change the mechanical connection state, thereby altering the vibration transmission characteristics and improving NVH performance while maintaining fuel efficiency during normal operation.
2Object-affected harmful factors
If the damper clutch is released to obtain smooth shift sense, then NVH characteristics are improved, but fuel economy deteriorates
Solution Approach 1:
Instead of keeping the damper clutch permanently released to maintain smooth shift sense, the controller applies partial action by releasing the clutch only when necessary - specifically when the engine operating point enters a resonance area detected through the NVH characteristic map. This selective release minimizes the impact on fuel economy while providing NVH improvement only when needed, rather than continuously.
3Object-affected harmful factors
If engine torque is increased to escape resonance area quickly, then NVH characteristics are improved, but engine load increases
Solution Approach 1:
The controller performs preliminary action by pre-identifying resonance areas through the NVH characteristic map before the engine actually enters them. When approaching a resonance area, the controller proactively increases engine torque to accelerate the engine out of the resonance region before significant NVH deterioration occurs, rather than reacting after the problem manifests.
Data Source
AI summary
A powertrain control method for a vehicle may include: setting, by a controller, a Noise Vibration Harshness (NVH) characteristic map based on an engine operating point to be used for a control of a powertrain based on a gradient of a road on which the vehicle is running; determining, by the controller, whether the vehicle is shifting; and selecting and performing, by the controller, at least one of a release of a lock-up state of a damper clutch or an additional rise of an engine torque based on whether a current engine operating point belongs to any level among a plurality of NVH levels classified in the NVH characteristic map when the vehicle is not shifting.