The vibration detecting method and mechanic analysis of valve trains of diesel engine

Through analyzing law of kinematics and dynamics for valve trains, the internal relation are revealed based on relational theory of the valve clearance, valve crash angle, valve crash speed and valve crash acceleration. Since the motion of valve trains brings the cylinder head into vibration, the vibration detecting method and mechanic analysis of valve trains of diesel engine is analyzed further by studying on the vibration frequency of the cylinder head to varying valve clearance, and the power spectrum numerical value is obtained about the drop response time and the vibration signal of the cylinder head when the valve clearance is more width or more narrow than its natural. The result of dynamic simulation is primary consistent with the test result of experiment. As a result of the power spectrum analysis about abnormal valve clearance, a new diagnosis analysis method is advanced abnormal diagnose of valve crash can be done via the time and energy parameters of valve crash cylinder head vibration signal. At the same time, the diagnosing about which valve seal not close is studied while the vibration signal of the cylinder head is made use of to detect valve leakage, it gets the key of diagnosing valve leakage that lies in analyzing its high-frequency component through emphasis selecting the sound source of turbulent current reflecting gas leakage level of the valve and the cylinder head vibration signal the maximum burning and exploding pressure step.