Power Train Oscillation Detection via Rotation Speed Cyclic Variation
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Solution Overview
Problem
Existing methods for detecting and damping power train oscillations in vehicles are complex and ineffective, leading to unsatisfactory results and increased computational complexity and implementation costs.
Innovation Solution
The method utilizes prime mover-related signals, specifically the rotation speed, to detect power train oscillations by analyzing changes in cyclic variation, and modifies the torque request to dampen oscillations using a derived inverted version of the cyclic variation, thereby reducing complexity and improving detection and damping efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If previous known solutions for damping power train oscillations are implemented, then damping capability is provided, but device complexity and computational complexity increase significantly
Solution Approach 1:
The patent extracts only the essential signal (prime mover rotation speed) needed for oscillation detection, discarding the complex multi-sensor approaches of prior art. By focusing solely on rotation speed cyclic variation, the solution achieves effective damping capability while minimizing device complexity.
Solution Approach 2:
The prime mover rotation speed signal serves multiple functions: it is used both for normal engine control and for oscillation detection. This multi-functionality eliminates the need for separate dedicated sensors or complex additional measurement systems, thereby reducing device complexity while maintaining damping capability.
2Reliability
If previous known solutions for damping power train oscillations are implemented, then damping capability is provided, but computational complexity increases significantly
Solution Approach 1:
The patent extracts only the essential feature (cyclic variation in rotation speed) needed for oscillation detection, eliminating the need for complex computational algorithms used in prior art. This extraction approach maintains damping capability while significantly reducing computational complexity.
Solution Approach 2:
Instead of analyzing complex vibration patterns and deriving oscillation characteristics through multiple computational steps as in prior art, the patent inverts the approach by directly using the cyclic variation of rotation speed as the detection criterion, thereby achieving effective damping with minimal computation.
3Difficulty of detecting and measuring
If detection is based on derivative of engine speed, then detection capability is provided, but detection delays occur and reliability decreases
Solution Approach 1:
The patent performs preliminary analysis of the rotation speed signal to identify cyclic variations before oscillations fully develop. By detecting the characteristic cyclic pattern in advance, the system achieves reliable detection without the time delays associated with derivative-based methods that wait for oscillation peaks.
Solution Approach 2:
The patent replaces the mathematical derivative operation with a direct analysis of cyclic variation patterns in rotation speed. This substitution eliminates the computational delays and reliability issues inherent in derivative-based detection while maintaining effective oscillation detection capability.
4Reliability
If additional sensors and complex systems are added for oscillation detection, then detection reliability is improved, but implementation cost increases
Solution Approach 1:
The patent makes the existing prime mover rotation speed sensor serve the dual purpose of normal engine control and oscillation detection. This eliminates the need for additional dedicated sensors or measurement systems, thereby achieving reliable detection without increasing implementation cost.
Solution Approach 2:
The existing rotation speed measurement system provides its own additional function (oscillation detection) without requiring external assistance or additional components. The system uses its own operational data (rotation speed variations) to detect oscillations, achieving reliable detection at no additional implementation cost.
Data Source
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Figure 2a~2c
Figure 2d~3a
AI summary
The present invention relates to a method for damping of a power train oscillation in a vehicle provided with a prime mover which rotates at a speed ?. According to the present invention, a vibration change S in the rotation speed ? of said prime mover is determined. There is deemed to be a power train oscillation if for a predetermined number of times the amplitude of said vibration change S is alternately above a positive threshold value Th1 1and below a negative threshold value Th2 and if all of the consecutive upward crossings of said positive threshold value Th1 and downward crossings of said negative threshold value Th2 are separated by a time shorter than a predetermined period T.