The noise of diesel engine group is a complex sound source composed of various sources. According to the method of noise radiation, it can be divided into aerodynamic noise, surface radiated noise and electromagnetic noise. According to the causes, the surface radiated noise of diesel generators can be divided into combustion noise and mechanical noise. The aerodynamic noise is the main noise source of the diesel engine group.
1. Electromagnetic noise is a diesel engine group noise generated by the high-speed rotation of the generator rotor in the electromagnetic field.
2. Aerodynamic noise is a diesel generator set noise due to the unstable process of gases, i.e. the disturbance of gases and the interactions between gases and objects. The aerodynamic noise directly radiated to the atmosphere, including inlet noise, exhaust noise and cooling fan noise.
3. Combustion noise and mechanical noise are difficult to distinguish strictly, usually due to the pressure fluctuation formed in the combustion of diesel generator cylinders through the cylinder head, piston, Lian Xuan, crankshaft, the body outward radiation of diesel engine group noise called combustion noise. The noise of the diesel engine group is called the mechanical noise by the piston to the cylinder liner collision and the mechanical impact vibration of the moving parts. The combustion noise of the general direct-injection diesel engine is higher than the mechanical noise, but the mechanical noise of the non-direct injection diesel engine is higher than the combustion noise. But the combustion noise is higher than the mechanical noise at low speed.