针对机动车油箱等容器棱角处纵向裂纹难以检测的问题，研制了一种基于差动式霍尔元件的多功能油箱漏磁检测装置。检测探头由两个霍尔元件构成差动式结构，以消除干扰磁场的影响，提高了检测系统的灵敏度；通过更换不同型号的励磁极靴分别实现油箱平面及棱角处纵向裂纹的检测；通过光电编码器使数据采集卡外触发实现了空域等距采样，进而实现对裂纹的定位。对含预制纵向裂纹的机动车油箱进行了漏磁检测试验，结果表明，该检测系统对油箱棱角处的内部纵向裂纹具有良好的辨识能力，能够推广到实际工业应用中。

In order to overcome the difficulties in detecting the longitudinal corner cracks of containers, such as motor vehicle oil tanks, are difficult to detect, a multifunctional system used to detect magnetic flux leakages of tanks is designed and developed based on differential hall probes. The detection probe is made of two elements forming the structure of differential type, make up the detection probe, which can improve the sensitivity of detection system. By switching different pole shoes, cracks of the plane and the corners can be detected respectively. As an external trigger, the photoelectric encoder can collect data at the same distance each time, to determine where the defect exists accurately. Through carrying experiments on the fuel tank belonging to a heavy armored vehicle with prefabricated defects, acquired results show that the detection system can identify the the longitudinal cracks inside the tank, then it can be promoted to industrial applications.