Study On Measuring Techniques For Crankshafts Vibration Of Ice

It is one of the important research fields of internal-combustion engine to study the crank shafting torsion of internal-combustion engine. By means of analyzing in-depth the two problems that exist in crank shafting torsion features of internal-combustion engine's non-stabilization rotate speed and the affecting factors of torsion vibration test accuracy, this thesis put up with the corresponding solutions. It is hoped that the analysis of the crank shafting torsion features of internal-combustion engine's non-stabilization rotate speed, the vibration testing of crankshaft bending, and the influences of the reverse vibration testing, could be of some significance to the internal-combustion engine's study both in theoretical and project pragmatic aspects.With the 4100QB diesel engine test-bed in the laboratory as the research base, this thesis analyzes the crank shafting torsion features of internal-combustion engine's stabilization, confirms the torsion modal during the the foremost two orders of shaft, and studies the impacts made upon the shaft torsion features by the stiffness of different shaft-connecting joints. Aiming at the problem of whether the additional alternating torque in the condition of internal-combustion engine's non-stabilization rotate speed exists; it confirms the non-existence of the additional alternating torque from the perspective of experiment. Having integrated the experimental data and emulation analysis, this paper makes a study to the influences on low order elements of torsion vibration signals made by the speed-increased trend. Besides, it adopts the root mean square value of fitting curves' windage vector as its evaluation standard.In the process of the torsion vibration experiment testing, it finds that the original voltage pulse signals of transducer sensor have been modulated regularly, and so this thesis analyzes this phenomenon in-depth. Through the experimental data analysis, it can be found that the above-mentioned phenomenon may be cause by the shaft bending vibration, and based on this analysis, this thesis designs a corresponding experimental program. Furthermore, by way of data analysis, it tests the shaft bending vibration in the process of torsion vibration testing and, confirming that shaft bending vibration does exist and the bending vibration could be reflected in the torsion vibration testing of the original voltage pulse signals and could make influences on the torsion vibration analysis accuracy.There are a couple of factors impacting the torsion vibration testing accuracy in the torsion vibration experiment and they are listed as follows:the stent vibration of magnetoelectric sensor, eccentricly-equipped velocity-measuring chainring and the shaft bending vibration. Through the theoretical derivation and emulation analysis, this thesis analyzes the influences on the torsion analysis accuracy made by the above three factors on a quantitative base and come up with the solutions to get rid of these influences. In view of the original voltage pulse signals of transducer sensor being modulated, this thesis adopts the 0 level as the standard level to calculate the instantaneous rotational velocity signals. The eccentricly-equipped velocity-measuring chainring could cause the he original voltage pulse and instantaneous rotational velocity signals to be modulated, the vibration angle to displace 1.0, and the order amplitude to increase obviously, and as for these influences, it can be solved through the measure of testing the magnetoelectric sensor in an opposite position. Aiming that the shaft bending vibration could make the original voltage pulse and instantaneous rotational velocity signals modulated, it can be dealt with by means of the integrated torsion vibration testing equipment, which could well get rid of the influences on torsion vibration testing made by eccentricly-equipped velocity-measuring chainring and the shaft bending vibration.