柴油机发动机噪声测试与分析

我们利用LMS噪声振动测试系统,对汉马动力10.5L柴油机的整体噪声水平进行了测试实验。结果表明,随着发动机负荷的增加,发动机的1 m平均噪声声压级在中低负荷时增加趋势平缓,高负荷时增加趋势较明显。在不同负荷下,发动机的1 m平均噪声声压级随着发动机转速的增加而增加。在转速为1 000~1 400 r/min的范围内,发动机平均噪声声压级增长平缓,说明发动机中速运行平稳。实验测试数据表明该款发动机油底壳处的声压级最高,对发动机噪声声压级贡献最明显,发动机顶部、左前、左后、右前以及右后侧的声压级较低,对发动机噪声声压级的贡献较小。同时测试数据表明,此款柴油机的噪声主要来源于中低频噪声,频率主要分布于300~6 000 Hz范围内。发动机在满负荷不同转速工作时,机械噪声大于燃烧噪声,随着加速过程的进行,每个位置的噪声声压级都增大,在不同载荷状态下,发动机加速过程运行较为平稳,无明显的噪声峰值出现,其中以半载加速最为平稳。

Test and Analysis on Diesel Engine Noise

Based on LMS noise and vibration test system, test experiments of overall noise level of HANMA Power 10.5 liter diesel engine were performed. Test results show that 1 m average sound pressure of the engine increases gently at low and medium load conditions;on the contrary, it increases sharply at high engine load with the engine load increase. And in the medium speed range of 1 000-1 400 r/min, the 1 m average sound pressure increases gently too and the engine runs smoothly. The test data also show that the position of maximum sound pressure of the engine is around oil-pan compared with top side, left side, right side and front side of the engine, oil-pan is the main radiated noise source. The noise frequencies of the engine are mainly in the range of 300-6 000 Hz which are all low and medium frequency components coming from mechanical radiated noise. When the engine runs in the full load condition, mechanical noise is bigger than combustion noise and the overall noise level increases accompanying speed-up. When the engine runs in speed-up with different engine load condition, the operation state is steady and no shock was found in the acceleration curve.