| Energy shortage and environment pollution are the two serious problems which faced by both the automobile and the engine industries.Noise reduction is one of the highest challenging targets for internal combustion engine development.Therefore,it is very important to investigate the noise control methods and analyse its main influence factors.The engine noise control is discussed.The engine surface-radiated noise prediction technology is introduced in the first part of this paper.Subsequently,the research method is determined in the research.The engine is a 2135AD type diesel engine of two-cylinder,from Nantong engine factory,which has been changed to biogas-diesel dual fuel generator.Many kinds of agricultural and forestry residues is gasified by a gasifier.The biogas is used as the main fuel of the dual fuel generator.The noise of diesel and dual fuel generator are investigated at the largest biogas substitute ratio and load characteristics.The one-third octave band spectrum of engine at different conditions are measured and analyzed.It is found that the engine is the main noise source of the generator.The noise of intake is the main noise source of the engine,then are the noise of oil pan and pulley.The noise of a turbocharged diesel engine is measured and analyzed.It is found that the noises of intake,oil pan,pulley are the main noise source,which is the same as the dual fuel generator.The engine noise is reduced by increasing the rigidity of block, valve cover,oil pan and so on.The experiment results indicate that the new block is better than the old block.It still has some problem,for example,the two-stage reciprocating inertial force is big,the noise of gearbox covers is big and so on. Therefore.other measures should be taken to reduce the noise futher. |
