Research On Optimization Of Combustion Noise Of A Heavy Duty Diesel Engine

Since the first car was introduced in 1886,cars have been playing an increasingly important role in people’s life.With the continuous improvement of people’s living standards,higher quality demands have been placed on the new vehicle.Since the beginning of the 21 st century,the performance of automotive NVH has received more and more attention from consumers.As the most intuitive sensory element,the noise performance of a car directly affects the evaluation of the car.Among them,engine noise is one of the main noise sources of the vehicle.Controlling engine noise has important practical significance.Diesel engines have a wide range of applications in the manufacturing and transportation industry,and their product performance is closely related to economic development.Due to its low speed and high torque working characteristics,diesel engine has the largest proportion of engine noise.With the wide application of supercharging technology and high pressure common rail technology,diesel engine combustion becomes more harsh while we are going to improve fuel economy.Therefore,the optimization of combustion noise is of great significance for improving the performance of diesel engine NVH.In this paper,in order to solve the NVH problem from one of diesel engine,the classification and generation mechanism of diesel engine noise were deeply analyzed.The in-cylinder combustion pressure is measured by measuring the engine cylinder pressure in the bench test.Combustion noise calculation can be carried out by cylinder pressure measurement and engine structure attenuation.The engine combustion state can be changed by adjusting key electronic control parameters such as fuel injection amount,interval angle and injection timing to optimize engine noise level.Improve comfort with dynamics.For the problem of abnormal vibration caused by uneven combustion under low-speed and small-load conditions,the torsional vibration angle is used as the evaluation method to optimize.At the same time,the paper applies the virtual technology to combine the multi-body dynamics and finite element calculation.System dynamics study,calculation and analysis of rolling vibration and torsional vibration characteristics of diesel engine and its shafting,and optimization of vibration from structural layerThis paper focuses on large displacement,high horsepower diesel engines,which includes engines equipped with electronically controlled unit pump fuel injection systems.The electronically controlled unit pump technology solution(FEUP)allows precise control of fuel injection time and fuel injection.However,compared with the diesel engine equipped with the electronically controlled high-pressure common rail system,the combination of the single pump has higher requirements for the control of the diesel engine vibration and noise.This paper mainly studies the diesel engine noise optimization with different fuel supply systems to ensure the noise is achieved.At the same time of development goals,the sound quality of the engine is also optimized and upgraded.The research shows that the effect of combustion noise optimization under medium and small load conditions is the most obvious.At this time,the refined combustion noise can be achieved through the fine adjustment of pre-spray quantity,rail pressure and combustion phase.At the same time,in order to ensure The diesel engine realizes the overall improvement of NVH performance.It also needs to pay attention to the optimization of the combustion transmission path under the heavy load condition of the diesel engine.The flywheel quality is an important factor affecting the rolling vibration characteristics of the crankshaft.It needs to be optimized in the development stage through simulation and experimental means.