Main Noise Sources of Diesel Generator

The noise of diesel generator mainly comes from diesel engine and generator. In order to reduce the noise of generator set, the main noise source should be controlled, and the key to the control is to find the main sound source accurately.

I Main noise sources of Diesel engines

1. Intake and exhaust noise

Intake and exhaust noise is the strongest noise source of diesel engine.

The intake noise is mainly the pressure pulsation of air in the intake pipe, the low frequency noise, the high frequency eddy current noise produced by the air flowing through the inlet valve section at high speed, and the noise of the turbocharger compressor of the turbocharged diesel engine.

The exhaust noise is mainly the pressure pulsation of exhaust gas in the exhaust pipe, which produces low and medium frequency noise, and the high frequency eddy current noise at the flow section of the exhaust valve.

2. burner noise

The combustion of combustible mixture in cylinder causes the rapid change of gas pressure, which causes the piston, cylinder head, connecting rod, piston pin, crankshaft and other parts to be subjected to impact load, resulting in structural vibration and noise.

3. mechanical noise

Due to the periodic changes and impact of the forces between the parts of the diesel engine, the surface vibration produces noise. The mechanical noise increases rapidly with the speed of the engine. The main parts of the mechanical noise are piston, cylinder head, cylinder block, cylinder liner, connecting rod, piston pin, crankshaft, valve train, gear, spray. The design of the components, the quality of the manufacturing and the selection of materials have an important effect on the noise. The structural stiffness of the diesel engine, the speed of the engine and the clearance of the moving parts are the main factors affecting the mechanical noise.

II Main noise sources of generators

1. ventilation noise

Electromagnetic noise is caused by the interaction of stator and rotor magnetic field in the air gap of generator to produce radial force varying with time and space, which causes the stator core and seat to deform periodically and cause vibration and noise.

2. electromagnetic noise

Electromagnetic noise is caused by the interaction of stator and rotor magnetic field in the air gap of generator to produce radial force varying with time and space, which causes the stator core and seat to deform periodically and cause vibration and noise.

3. mechanical noise

The mechanical noise of generator includes mechanical vibration and noise caused by centrifugal force caused by rotor mechanical imbalance, vibration noise of bearing, sliding contact noise of brush collector ring or commutator, axial vibration noise of end cover excited by bearing vibration.