Experimental Study On Outlet Particulate Emission Characteristics During DPF And GPF Regeneration

Diesel Particulate Filter（DPF,Diesel Particulate Filter）and Gasoline Particulate Filter（GPF,Gasoline Particulate Filter）are the most effective devices to reduce diesel and gasoline engine particulate matter（PM）emissions and improve diesel and gasoline engine exhaust pollution.After a period of time of PM deposited,the exhaust pressure,the fuel consumption will increase and the power will decrease.Therefore,it needs to be oxidized and regenerated regularly.The study of the discharge of DPF and GPF outlets during regeneration is important for controlling the particle emission,which is practical and crucial to the regeneration strategy.Based on the external heating source regeneration performance test bench,this paper conducts experiments on the outlet particle emission characteristics and studies the incoming flow parameters,ash deposition,gas emissions,and outlet particle emissions during DPF and GPF regeneration.All the experimental figures are analyzed in detail.First,the exhaust gas and particulate emission characteristics of DPF during regeneration under different regeneration temperatures and incoming flow rates are studied.The results are as follows:The process of regeneration has a rapid regeneration period.As the regeneration temperature increases,the period shortens.The CO and CO₂concentration at the DPF outlet increases,and the discharged aggregated PM increases,the regeneration efficiency increases accordingly.As the incoming flow increases,the time of the rapid regeneration is prolonged,and the CO and CO₂ concentration at the DPF outlet decreases.When the incoming flow rate is 25.2g/s,the aggregated particles are significantly reduced,but the regeneration efficiency and efficiency ratio are also the lowest.According to the outlet gas emissions,it can clearly reflect the regeneration of the DPF and provide an important test reference for the formulation of regeneration strategies.Then,the influence of different ash particle sizes and ash loading on the emission of particulate matter during the regeneration of GPF is studied.The results are as follows:compared with ash-free deposition,the 2μm 1#ash will make it difficult for PM to blow out of the GPF under the action of the incoming flow when get heated.It can promote the regeneration of the GPF,because the regeneration temperature is475℃.The particles can burn in large quantities and release more particles,and its regeneration efficiency and total mass concentration are relatively high;while the 15μm2#ash will cause the particles released significantly during the heating stage,but it does not significantly promote the regeneration of GPF.The regeneration efficiency and total mass concentration are relatively low.Compared with no ash,5g/L of 3#ash promotes the release of PM during the heating stage,which causes the load increase to 15g/L.The more obvious the promotion effect is observed in the experiments.In the regeneration stage,depositing 15g/L will change the morphology of the external particles during GPF regeneration,most of which are mainly aggregated.Secondly,comparative study of the regeneration performance of DPF and GPF under different regeneration temperatures,incoming flow and ash deposition.The results show that under different regeneration temperatures and incoming flow rates,the number of particles at the GPF outlet fluctuates more smoothly,the average particle size is smaller.The particles in the experiments are dominated by nuclear mode.The maximum temperature inside the GPF carrier is slightly higher than that of the DPF carrier,and its regeneration efficiency is higher.Compared with other ash,when the small particle size elemental ash（Al₂O₃）of 2μm is deposited,the highest temperature inside the carrier during DPF and GPF regeneration is higher.Furthermore,the regeneration efficiency is the highest.The higher the regeneration temperature,the more obvious the promotion effect of ash.When deposited 10μm mixed ash（Al₂O₃+Si O₂）,It is increasing the loading of ash that will promote the regeneration of DPF,but has little effect on the regeneration of GPF.When deposited 15μm large particle size elemental ash（Al₂O₃）,it will promote the regeneration performance of DPF,but it will inhibit the regeneration performance of GPF.Finally,the high-temperature filtration characteristics of DPF and GPF are explored,and the influence of carbon black loading,transition section,filtration temperature on the particle emission characteristics of the carrier outlet are studied correspondingly.The results are as follows:after adding DPF and GPF carriers,the range of fluctuation becomes smaller.What’s more,with the filtration temperature increases,the concentration range of the outlet PM becomes smaller.At the same time,the collection efficiency of DPF and GPF carriers will gradually decrease and then level off.With different loadings of carbon black,as the filtration temperature increases,the collection efficiency shows a downward trend.Appropriate carbon black deposition can increase the capture efficiency of the DPF carrier,which is beneficial to intercept PM.The capture efficiency is the highest at a loading amount of 2.5g/L carbon black,which is 92%.However,continuing to increase the loading of carbon black will reduce the collection efficiency of the DPF carrier.When the loading of carbon black is 10g/L,the promotion effect is the lowest.After the 50cm transition section is added,the fluctuation range of the DPF carrier becomes smaller,and the concentration range of the outlet PM becomes smaller as the filtration temperature increases.However,with the increase of filtration temperature,the trap efficiency of the 0cm transition section shows a downward trend,and the trap efficiency of the 50cm transition section tends to be stable,and the trap efficiency of the transition section is lower than the 0cm transition section,which requires a comprehensive trade-off.Through the above research,it is found that there is a rapid regeneration period in the regeneration of the DPF,and the regeneration efficiency is calculated by the conversion algorithm of gas emission,so as to monitor the regeneration situation inside the DPF in real time.It is concluded that the small particle size ash promotes the regeneration situation and the large particle size ash inhibits.It shows the influence of different ash particle size and ash loading on the emission of particulate matter during GPF regeneration.Through comparisons,it is found that the regeneration performance changes of DPF and GPF under different regeneration temperature,incoming flow and ash deposition.And,it is found that the collection efficiency of GPF will be higher than that of DPF,and it shows that the carbon black loading and the transition section changes with the filtration temperature.