We all know that the noise of diesel generator sets is very big, so for you to analyze the source of the noise of diesel generator sets:

　　1. Exhaust noise

　　Exhaust noise is a kind of pulsating air flow noise with high temperature and high speed. It is the most energy and component part of engine noise. It is much higher than the intake noise and the mechanical noise of the body radiation, which is the most important component of the total engine noise. Its fundamental frequency is the firing frequency of the engine.

　　The main components of exhaust noise are as follows: The low frequency pulsation noise caused by periodic smoke exhaust, the gas column resonance noise in the smoke exhaust pipe, the Helmholtz resonance noise of the cylinder, the noise generated by the high-speed air flow through the valve clearance and the winding pipe, the eddy current noise, and the regeneration noise generated by the pressure wave excitation of the smoke exhaust system in the pipe, etc., the noise frequency increases significantly with the increase of the airflow speed.

　　2. Mechanical noise

　　Mechanical noise is mainly the engine moving parts in the process of operation by gas pressure and the periodic change of motion inertia force caused by vibration or mutual impact, among which the most serious are the following: noise of piston crank connecting rod mechanism, valve mechanism noise, transmission gear noise, unbalanced inertia force caused by mechanical vibration and noise.

　　The strong mechanical vibration of a diesel generator set can be spread far outdoors through the ground, and then form noise through radiation from the ground. This structure noise spread far, decline reduced, once formed is difficult to isolate.

　　3. Combustion noise

　　Combustion noise is the structural vibration and noise produced by diesel oil during combustion. The sound pressure level of combustion noise in the cylinder is very high, but the rigidity of most parts in the engine structure is high, and the natural vibration frequency is mostly in the middle and high frequency region. Due to the mismatch in the response to the acoustic wave propagation frequency, the peak value of the cylinder pressure level in the low frequency band is not smooth, while the cylinder pressure level in the middle and high frequency band is relatively easy to get out.

　　4, cooling fan and exhaust noise

　　Fan noise is composed of eddy current noise and rotating noise. The rotating noise is caused by the periodic disturbance of the air flow cut by the fan blade. Eddy current noise is generated when the air flows separate on the rotating blade section. The eddy flow caused by the viscosity of the gas radiates an unstable flow noise. Exhaust noise, airflow noise, fan noise and mechanical noise are radiated out through the exhaust channel.

　　5. Air inlet noise

　　The diesel generator set needs to have enough fresh air supply when it is working normally, on the one hand, to ensure the normal operation of the engine, on the other hand, to create good heat dissipation conditions for the unit, otherwise the unit cannot guarantee its performance. The air intake system of the unit basically includes the air intake channel and the air intake system of the engine itself. The air intake channel of the unit must be able to make fresh air enter the room smoothly, and the mechanical noise and airflow noise of the unit can also radiate to the outside of the room through the air intake channel.

　　6. Generator noise

　　Generator noise includes electromagnetic noise caused by magnetic field pulsation between stator and rotor and mechanical noise caused by rolling bearing rotation.

　　According to the above noise analysis of diesel generator set. Generally, the following two processing methods are adopted for the noise of the generator set:

　　Oil room for noise reduction treatment or procurement of anti-sound type unit (its noise in 80db- 90db).