A High-sensitivity Knock Sensor Based on ZnO Nanowires Array as Piezoelectric Nanogenerator

We develop a new ZnO nanowire (NWs) array knock sensor based on a piezoelectric nanogenerator. The ZnO NWs arrays generated by the hydrothermal method are deadlocked so that the tops of the two arrays are in contact with each other to form a closed circuit, thereby generating a new type of piezoelectric nanogenerator. On this basis, the ZnO NWs array knock sensor was developed for the first time with this piezoelectric nanogenerator as the crux element and installed on an engine to measure the voltage characteristics. By comparing the low-speed and high-speed output voltage characteristics of simulated knocking, high-intensity knocking can output a larger voltage, while knocking can generate a higher voltage within 0.02 s.