基于频率解调方法的柴油机瞬时转速信号计算

Calculation of Instantaneous Rotational Speed of Diesel Engine Based on Frequency Demodulation

运用磁电传感器测量柴油机转速时,对所得电压信号进行处理可得到瞬时转速。分别采用计数法和频率解调法得到了柴油机的瞬时转速,比较了结果的差异。不考虑齿轮的齿形和分度误差,计数法的幅值误差主要取决于采样频率,采样频率越大误差越小,因此需要很高的采样频率;而频率解调法误差主要来源于采样噪声和信号处理过程,该方法不需要很高的采样频率,从而降低了瞬时转速测量的硬件要求,具有很强的现实推广意义。

Instantaneous rotational speed of diesel engine can be obtained from the voltage measured by magneto-electric transducer, which is calculated by using Counting method and Hilbert transform method, respectively. The amplitude errors of counting method is determined by the sample rate, despite of gear teeth shape errors and gear teeth graduation errors. To get smaller errors, sample rate must be higher enough. On the other hand, noise and signal processing method influence amplitude errors of the frequency demodulation method, not requiring too high sample frequency, which decrease the measurement hardware demand meaningfully.