Crank it up: modern emerging powertrain noise analysis techniques allow more precise results

摘要

Two methods of measuring signal representation via crank angle were discussed. The method of time variable, speed controlled sampling acquires samples of the signals at equidistant angular positions of the crank shaft rotation. In contrast, the method of equidistant sampling takes samples of the signals at a constant sampling rate. By resampling, the amplitudes of the signals are evaluated at the points of time of the respective crank angles. Besides the desired signals, both measuring methods require the acquisition of the engine speed to determine the current crank angle and an additional signal to synchronize the signals wanted to the respective duty cycle. Apart from varying the resolution of the crank angle after the measurement was finished, the method of constant sampling also allows the easy use of standard multichannel measurement systems. The signals are also available for other types of signal analysis.