中文摘要：

提出一种无需编码盘和鉴相装置的往复发动机瞬态转速测量新方法。该方法是基于发动机振动信号最低谐次频率获得发动机的估计转速，在发动机转速平稳或波动不大情况下采用离散频谱校正技术对估计转速进行校正以提高测量精度；在发动机处于升速或降速等非平稳状态时则利用获得的估计转速对发动机进行阶次跟踪，利用阶次谱获得估计转速校正参数，从而实现对发动机瞬态转速的动态测量。台架实验和不同缸数的实车测试都验证了该算法在发动机转速提取上具有很高的精度。较之在文献中常见的基于编码器的转速测量方法，这种方法硬件简单，特别适用于在用车日常维护和检测中使用。

英文摘要：

Without encoder and phase discriminator a transient measurement method for rotation speed of the reciprocating engine is proposed in the paper. The coarse rotation speed of the engine is obtained from the components of the lowest harmonic frequency in its vibration signals. When the engine speed has little fluctuation, a discrete spectrum correction technique is employed to improve measurement precision of the speed. When there is a large speed variation, such as in its speed-up and speed-down stages, the vibration signals are re-sampled corresponding to the coarse rotation speed. By the order-tracking technique based on the re-sampling data, a correction factor and the transient rotation speed of the engine are obtained accord- ingly. Results from the tests on bench and real engines with different number of cylinders prove that the proposed method can achieve a high precision. Comparing to the other usual measurement methods with encoder, the proposed method is simple in hardware, does not need any pre-knowledge of the cylinder number of the tested engine, and is particularly suitable for routine inspection and maintenance of the vehicles.