Engine RPM Control via Fourier Transform Vibration Suppression
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Solution Overview
Problem
Existing engine control systems fail to effectively attenuate excited vibrations during engine driving, leading to increased noise and user dissatisfaction, particularly at cold temperatures due to coupling of drive system resonance frequency and idle fuel amount control.
Innovation Solution
A method for controlling engine RPM that involves a frequency deriving process, followed by a frequency conversion using Fourier Transform, comparison with a reference frequency, and adjustment of fuel injection amount to reduce vibrations, utilizing filters like short time mean value and bandstop filters to remove excessive frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional idle fuel amount control is used, then engine RPM can be maintained, but vibration and noise increase due to resonance coupling
Solution Approach 1:
The controller continuously monitors engine RPM and calculates frequency components through Fourier transform, then adjusts fuel injection amount based on the magnitude of resonance frequencies. This closed-loop feedback mechanism dynamically suppresses vibrations by comparing actual RPM fluctuations with target RPM and applying corrective fuel injection adjustments.
Solution Approach 2:
The system changes the fuel injection amount parameter dynamically based on detected resonance conditions. By calculating the magnitude of frequency components and comparing with threshold values, the controller adjusts the fuel injection rate to shift engine operating parameters away from resonance conditions, thereby reducing vibration and noise.
2Object-affected harmful factors
If fuel injection amount is adjusted to suppress vibration, then noise and vibration reduce, but engine RPM control complexity increases
Solution Approach 1:
The patent replaces complex mechanical vibration suppression systems with an electronic control system that uses Fourier transform algorithms to analyze RPM fluctuations. The controller calculates frequency components electronically and adjusts fuel injection through electronic actuators, substituting mechanical complexity with computational processing.
Solution Approach 2:
The controller performs periodic Fourier transform calculations on engine RPM data at regular intervals during idle operation. This periodic analysis allows the system to continuously identify resonance frequencies and adjust fuel injection in a rhythmic manner synchronized with engine cycles, effectively suppressing vibrations without requiring continuous complex computations.
3Ease of operation
If resonance frequency coupling occurs during cold operation, then engine starts can be achieved, but vibration becomes more serious
Solution Approach 1:
The controller applies vibration suppression control from the moment engine starting is detected. By preliminarily activating the Fourier transform-based frequency analysis and fuel injection adjustment mechanism during cold operation, the system prevents resonance-induced vibrations before they intensify, rather than attempting to suppress them after the problem occurs.
Solution Approach 2:
The system dynamically adapts its control strategy based on operating conditions. During cold operation, the controller continuously monitors RPM fluctuations and adjusts fuel injection amount in real-time based on detected resonance frequencies. This dynamic adjustment allows the engine to achieve stable starting while simultaneously suppressing vibration that would otherwise intensify during cold conditions.
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
Significantly reduces or removes vibrations and noise, enhancing user satisfaction and brand image by stabilizing engine RPM and preventing resonance-induced vicious cycles.
Implementation Method 1
The frequency conversion process may include converting the derivation frequency into the conversion frequency using Fourier Transform.
Data Source
AI summary
A method for controlling engine revolution per minute (RPM) includes: a frequency deriving process for deriving a frequency from change in engine RPM detected by a detector by a controller during driving of the engine; a frequency conversion process for converting a derivation frequency derived in the frequency deriving process into a conversion frequency via a predetermined conversion process by the controller; a frequency comparison process for comparing an amplitude of the conversion frequency at which engine RPM is to be changed among conversion frequencies converted in the frequency conversion process with an amplitude of a reference frequency pre-inputted to the controller; and a fuel injection amount adjusting process for deriving a correction value based on a result derived in the frequency comparison process, for applying the derived correction value, and for controlling an injector by the controller to adjust a fuel injection amount.