发动机曲轴轴承异响严重影响发动机工作性能。 现有的人工经验听诊法和仪器辅助诊断法都难以快速甄别发动机曲轴轴承异响, 为此创新性地提出了利用原子吸收光谱法判定汽车发动机曲轴轴承异响故障。 对行驶里程分别1 000~28 000 km, 取样间隔约为1 000 km, 40批次的迈腾2.0发动机润滑油油液样品经微波消解处理后, 在高温下转化成原子蒸气, 由待测含量物质相同元素做成的空心阴极灯辐射出一定波长的特征辐射, 通过石墨炉加热后一部分被基态原子发射。 测定吸光度后, 再根据由标准系列试样作出的浓度-吸光度工作曲线上, 查出油液样品中的主要金属Cu, Pb含量, 建立同一车型发动机不同行驶里程数润滑油主要金属Cu, Pb含量的数据库。 研究结果表明主要金属Cu, Pb含量随着汽车行驶里程数在一定范围内波动。 在实际工程应用中, 通过测定有发动机曲轴轴承异响发动机的润滑油中主要金属含量, 将其与含量变化趋势图进行比对, 在不解体状态下, 可帮助汽车检测维修人员判定汽车发动机曲轴轴承异响, 降低汽车维修成本, 提高了发动机曲轴轴承异响故障诊断的准确性。

The present study was carried out to detect crankshaft bearing knock using atomic absorption spectrometry (AAS) in an innovative way. Lubricating oil of MAGOTAN 2.0 with mileage of 1000~28000Km and sampling interval of 1000Km changed into atomic vapor in the heat after digesting with microwave. Hollow-cathode lamp made of the same element with metal content under test would radiate characteristic radiation with certain wavelength. A part of atomic vapor was launched with ground state atom after heating with graphite furnace. Concentration-absorbance working curve was finished with standard series sample after absorbance was measured. Finally, element content under test in oil was obtained based on the work curve. Database of primary element (Cu and Pb) content of lubricating oil in the same engine with different mileage was established. Results showed that Cu, Pb content fluctuates with different mileage in a certain range. In practical engineering applications, primary metal content in lubricating oil of engine crankshaft bearing was measured and compared with content variation trend chart. This new method not only helps automobile maintenance personnel to diagnose crankshaft bearing knock under no-disintegration situation but also is benefit for reducing the maintenance cost of automobile greatly and improving diagnostic accuracy of crankshaft bearing knock.