The non-contact measurement of engine speed can be realized by analyzing engine vibration frequency. However, the vibration signal is distorted by harmonics and noise in the measurement. This paper presents a novel method for the measurement of engine rotation speed by using the cross-correlation of vibration and acoustic signals. This method can enhance the same frequency components in engine vibration and acoustic signal. After cross-correlation processing, the energy centrobaric correction method is applied to estimate the accurate frequency of the engine's vibration. This method can be implemented with a low-cost embedded system estimating the cross-correlation. Test results showed that this method outperformed the traditional vibration-based measurement method.

中文翻译：

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非接触式发动机转速测量的振动和声信号分析。

发动机转速的非接触式测量可以通过分析发动机振动频率来实现。但是，振动信号会因测量中的谐波和噪声而失真。本文提出了一种利用振动和声学信号的互相关来测量发动机转速的新方法。该方法可以增强发动机振动和声音信号中的相同频率分量。经过互相关处理后，应用能量重心校正方法来估计发动机振动的准确频率。该方法可以用低成本的嵌入式系统来估计互相关。测试结果表明，该方法优于传统的基于振动的测量方法。