What are the general noise faults of small excavators?
Under normal circumstances, as the vehicle speed increases, small excavators can repair the noise of the diesel engine. Noise generation mechanism: During the operation of the diesel engine, the exhaust valve flow is unstable. Although it is sent to the outlet of the exhaust system in the form of pressure fluctuations, there will be speed fluctuations at the outlet of the exhaust pipe. Radiation noise will be generated, and we can also see that exhaust noise is caused by unstable airflow in the exhaust system. Exhaust noise is usually defined as the total noise emitted by the exhaust system. This includes radiated noise from pipes and muffler walls and aerodynamic radiated noise from the exhaust pipe outlet. If the exhaust system is rigid, exhaust noise is referred to as aerodynamic noise. The main factors that will affect exhaust noise are engine speed, number of cylinders, load and exhaust pipe size.
When the internal combustion engine starts to exhaust, the temperature of the small excavator is about 800-1000 degrees Celsius and the pressure is about 0.4-0.5 MPa. However, when the exhaust valve is opened in the gap, exhaust gas is discharged from the gap in pulses. High-energy complex frequency noise. According to the noise mechanism in the exhaust process, the following components can be used:
1. Air pulsating sound;
2. Vortex generated by valve and valve seat.
3. Noise caused by boundary layer turbulence.
4. The sound of the exhaust nozzle. In the exhaust noise spectrum of a multi-cylinder diesel engine, there is usually a larger noise peak at low frequencies, which is the basic noise.
The combustion process of a diesel engine is usually divided into four stages: ignition delay period, flash burn period, slow burn period and afterburn period. The basic knowledge of small excavator maintenance includes equipment maintenance, equipment inspection and equipment maintenance. In order to strengthen the maintenance of small excavators, relevant maintenance personnel need to further analyze the damage according to the actual situation and quality problems. When analyzing the reasons, it is generally caused by natural wear and tear, and targeted research is required. The research of diesel engine combustion process generally adopts pressure curve (P center) analysis method.
Cylinder pressure and combustion noise are periodic phenomena, and the cylinder pressure frequency is divided into frequency components of combustion noise. Fourier analysis of cylinder pressure and combustion sound is based on sound pressure level. The selection of the ignition process is based on the fuel injection method, in which the cooling process and the working process are very important.
This is an understanding of the noise problem of small excavators, I hope it will help you.