Views: 330 Author: Site Editor Publish Time: 2020-06-27 Origin: Site
Engine, gearbox and other parts are the main noise sources of the tractor. Engine noise is mainly composed of intake and exhaust noise, combustion noise and mechanical noise. The exhaust noise is the strongest of several separate sources.
The intake noise is related to the structure of the filter. An air filter with good cleaning effect has better noise reduction effect. For example, the intake noise of a paper fine filter with a cyclone coarse filter and a long pipe is lower than that of an oil bath air filter.
Combustion noise is the pressure impact caused by gas explosion, which causes deformation and vibration of cylinder head and body. This vibration is transmitted to surface parts, such as cylinder head cover, inlet and exhaust pipe, and radiation noise. It is related to the structure combustion process, usually the diesel engine with higher pressure increase ratio and pressure increase rate in cylinder will have greater noise, which is related to the design of diesel engine.
The exhaust noise is the main noise source which makes the engine noise exceed the standard. In order to control exhaust noise, the inner wall of exhaust channel should be kept smooth and unobtrusive, and sharp bends should be avoided. Exhaust muffler is the most effective measure to control exhaust noise.
Mechanical noise is the noise emitted by the surface vibration of the external part caused by the mechanical excitation force of the moving part. The poor technical condition of the old diesel engine is more intense than the general diesel engine, because the clearance of each part of the old diesel engine is large, such as the piston and cylinder liner clearance reach the upper limit, the tractor engine will make a tapping sound when working.
Long-term exposure to high decibel noise will harm people's physical and mental health. In addition to the complete solution from the design structure to reduce tractor noise, we can also take the following several measures.
The muffler shall be installed firmly, the joint shall be sealed, and the muffler shall not be damaged.
The noise of sudden acceleration is much higher than the noise of full load. The noise index of tractor is also the noise of sudden acceleration from low speed to full speed. Since it is much larger and harshest than at a constant speed, the noise of a diesel engine can be reduced by 3-4 to 5.33 dB depending on the speed of the engine.
The air filter must also be firmly installed and not wobbly. The diesel engine with decreasing power and increasing fuel consumption must be repaired in time. Keep regular maintenance, timely oil change and the replacement of wear parts beyond the limit.
When the throttle handle of the diesel engine is placed in the limit position, the maximum free and negative load speed regulation shall not exceed 2160 r/min. Do not increase the speed by improper methods without authorization. The test shows that after taking measures (i.e. limiting oil, limiting speed, installing efficient muffler), the noise is accelerated from 85. 9 dB down to 78. 4 dB.
When assembling the tractor, the dynamic balance experiment of rotating parts should be done carefully to ensure the accurate dynamic balance of the tractor. In particular, the assembly of crankshaft, flywheel, piston, connecting rod and other parts with high precision must meet the requirements of installation precision. For gear, bearing and other parts, it is necessary to improve the machining accuracy of the parts, strictly control the key parameters and key points in the assembly process, and ensure the assembly accuracy, so as to reduce the inertial impact force of gear and other rotating parts and reduce the noise generated by vibration.