Analysis And Optimization Study Of The Self-cleaning Performance For Heavy Duty Vehicle Air Filter

Vehicles play a vital role in people’s life and work.According to the announcement of the ministry of public security,by the end of 2021,the number of motor vehicles in China was 395 million,of which the number of the heavy duty vehicles is about 11 million.The filter element is replaced once every three months,about 44 million air filter elements of heavy duty vehicles are required in a year.The huge market of automobile air filter elements has promoted the development and improvement of air filters and filter elements of heavy duty vehicles.The filters of heavy duty vehicles are in use for a long time,the air filter will have problems easily such as bag sticking,high resistance and even damage,which will seriously affect the operation of power equipment.Therefore,the air filter element and air filter with self-cleaning ability have been invented and used to reduce the replacement cost of the air filter element,prolong the service time of the air filter element,improve the filtration efficiency of the air filter,and ensure the safe and efficient operation of heavy vehicle engine with highly efficient self-cleaning performance.Combined with experiments and numerical simulation,this work studied the dust-cleaning performance of self-cleaning heavy vehicle air filter.Firstly,in terms of experiments,the research was carried out in two stages.The first stage was the peak wall pressure experiment.By measuring the peak wall pressure of the filter element,this work investigated the effects of the pulse pressure and pulse width on the peak wall pressure of the self-cleaning air filter element,and obtained the pressure distribution on the filter element surface during the pulse dust-cleaning process.This part of the experimental data was used to verify the numerical calculation model of pulse dust cleaning of self-cleaning air filter.The second stage was the powder attachment experiment.The dust was evenly attached to the filter element,which simulated the clean dust under different working environments and different dust holding states.The effects of pulse pressure,dust quality and dust moisture content on the dust stripping rate were explored to obtain the dust cleaning effect after practical application.At the same time,the dust cleaning process of self-cleaning heavy vehicle air filter was photographed by camera.Then,the dust-cleaning performance of the self-cleaning air filter was studied by three-dimensional and unsteady numerical simulation method.By changing the injection pipe length,the nozzle diameter and the pulse pressure,and using the peak wall pressure and the relative standard deviation of velocity as evaluation indexes,this work investigated the effects of various influencing factors on the pulse dust-cleaning performance of air filter.Combined with the response surface method,the peak wall pressure was used as the response value to explore the effects of the injection pipe length,the nozzle diameter,the pulse pressure and the pulse width on dust-cleaning performance.And the structural parameters and operating parameters were optimized in the process of air filter self-cleaning.The following conclusions can be obtained.(1)The peak wall pressure experiments show that the peak wall pressure increases with the pulse pressure.When the pulse pressure increases from 0.5MPa to0.8MPa,the peak wall pressure of self-cleaning air filter increases from 2271 Pa to3875 Pa.With the increase of pulse width,the change of peak wall pressure is small.The maximum pressure difference is 165 Pa,which is almost negligible compared with 3445 Pa.(2)The powder attachment experiments show that the higher the pulse pressure is,the greater the dust stripping quality is,the higher the dust stripping rate is,and the better the dust cleaning effect of the self-cleaning air filter is.The greater the dust quality is,the smaller the dust stripping quality is,the lower the dust stripping rate is and the worse the dust cleaning effect is.The greater the dust moisture content is,the smaller the dust stripping quality is,the lower the dust stripping rate is,and the worse the dust cleaning effect is.Through the dust cleaning process of the self-cleaning air filter,the dust falls off from the pleated filter element in 0～400ms,and the maximum dust removal appears in 400 ms.From 400～720ms,some of the stripped dust falls back on the surface of the filter element,and the secondary dust lifting has a greater impact on the dust-cleaning results.(3)Comparing the peak wall pressure of the air filter from the porous medium and standard k-? model with the pressure data obtained from the experiment,it is found that the error between the two is within 15%,which shows that the established numerical model can be used for the numerical simulation of the dust-cleaning performance of the heavy vehicle air filter.The numerical simulation results show that when the injection pipe is short,the peak pressure change is small.When the injection pipe is long,the peak pressure change shows a sharp upward trend.When the injection pipe length is 345 mm,the peak wall pressure is the largest and the flow uniformity is the best,so its dust-cleaning performance is the best.With the increase of nozzle diameter,the peak wall pressure increases and the relative standard deviation decreases.When the nozzle diameter is 22 mm,the peak wall pressure is the largest and the flow uniformity is the best,so its dust-cleaning performance is the best.With the increase of pulse pressure,the peak wall pressure increases and the relative standard deviation decreases.When the pulse pressure is 0.8MPa,the peak wall pressure is the largest and the flow uniformity is the best,so its dust-cleaning performance is the best.(4)The dust-cleaning performance of self-cleaning heavy vehicle air filter is optimized by response surface method,combined with the analysis of variance and regression coefficient test.The significant degree of four factors on dust cleaning is the nozzle diameter > the pulse pressure > the injection pipe length > the pulse width.The effect of pulse width on dust cleaning is insignificant.The best dust cleaning conditions obtained by response surface method are L=345mm,D=22mm,P=0.8MPa and T=150ms.The peak wall pressure obtained by response surface method is6012.24 Pa.