Forestry and gardening machinery. Vibration test code for portable hand-held machines with internal combustion engine. Vibration at the handles

2012 ◽  
Keyword(s):  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Vibration Test ◽  
Engine Vibration

The Time-Frequency Analysis Method Based on EMD White Noise Energy Density Distribution Characteristics of the Internal Combustion Engine Vibration

2013 ◽  
Vol 328 ◽  
pp. 367-375 ◽  
Author(s):  
Guo Yan Feng ◽  
Yan Ping Cai ◽  
Yan Ping He
Keyword(s):  
Energy Density ◽  
Internal Combustion Engine ◽  
White Noise ◽  
Combustion Engine ◽  
Vibration Signal ◽  
Internal Combustion ◽  
Distribution Characteristics ◽  
Energy Density Distribution ◽  
Time Frequency ◽  
Engine Vibration

For the limitations of HHT of the internal combustion engine vibration signal analysis, and the problem of WVD cross-term suppression methods existing aggregation and cross-term component suppression conflicting, the time-frequency analysis method based on EMD white noise energy density distribution characteristics of the internal combustion engine vibration is proposed. First, the internal combustion engine vibration signal was decomposed into the independent series intrinsic mode function (IMF) with different characteristic time scales by using EMD decomposition method. Then, based on the energy density distribution characteristics of the white noise in EMD decomposition, used the distribution interval estimation curve of the IMFs energy density logarithm of white noise with the same length of the original signal as cordon for false pattern component, identified and eliminated false mode component of vibration signal IMFs component, analysised of each IMF with Wigner-Ville. Finally, the Wigner-Ville analysis results of each IMF were linear superposed in order to reconstruct the original signal time-frequency distribution. Simulation and engine vibration time-frequency analysis results show that this method has an excellent time-frequency characteristics, and can successfully extract feature information of the internal combustion engine cylinder head vibration signal.

Fully Coupled Rigid Internal Combustion Engine Dynamics and Vibration—Part II: Model-Experiment Comparisons

2001 ◽  
Vol 123 (3) ◽  
pp. 685-692 ◽  
Author(s):  
D. M. W. Hoffman ◽  
D. R. Dowling
Keyword(s):  
Internal Combustion Engine ◽  
Model Experiment ◽  
Combustion Engine ◽  
Correlation Coefficients ◽  
Peak Torque ◽  
Internal Combustion ◽  
Engine Block ◽  
Model Parameters ◽  
Engine Vibration ◽  
Heavy Duty Diesel

In internal combustion engine vibration modeling, it is typically assumed that the vibratory state of the engine does not influence the loads transmitted to the engine block from its moving internal components. This one-way-coupling assumption leads to energy conservation problems and does not account for Coriolis and gyroscopic interactions between the engine block and its rotating and reciprocating internal components. A new seven-degree-of-freedom engine vibration model has been developed that does not utilize this assumption and properly conserves energy. This paper presents time and frequency-domain comparisons of this model to experimental measurements made on an inline six-cylinder heavy-duty Diesel engine running at full load at peak-torque (1200 rpm) and rated (2100 rpm) speeds. The model successfully predicts the overall features of the engine’s vibratory output with model-experiment correlation coefficients as high as 70 percent for vibration frequencies up through third engine order. The results are robust to variations in the model parameters. Predictions are less successful at the detail level and at higher frequencies because of uncertainties in the actual imperfections of the test engine, and because of the influence of unmodeled engine components.

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