Research On DPF Soot Loading And Regeneration Characteristics At Different Altitudes

The Diesel Particulate Filter(DPF)is currently recognized as the most effective particle treatment device and is an essential post-processing system for diesel engines of the National Five and above.How to improve the efficiency of soot capture while achieving safe and reliable fuel-saving regeneration has always been the key to the research of diesel particulate traps.The newly issued National Sixth Emission Regulations strictly stipulates the limits of vehicle emission pollutants at different altitudes.It is necessary to properly control the original emissions and exhaust heat status of diesel engines according to engine operating conditions,operating environmental conditions,and DPF regeneration efficiency.Parameters,so as to ensure the effective control of particulate emissions in different operating environments under the premise of ensuring the power and economy of the diesel engine.Therefore,the research on soot loading and regeneration characteristics of DPF at different altitudes can provide a scientific basis for the optimal control of diesel engine combustion and emissions in high altitude environment.The D20 high-pressure common rail diesel engine that meets the national five emission standards is the research object.Combined with the atmospheric simulation device,the DPF post-processing system is coupled with the engine test bench.The research method combined with the test and simulation is used to carry out the WHTC transient at different altitudes.Cyclic emission test,DPF soot loading and pressure drop,and regeneration temperature field and pressure drop test;on this basis,a DPF onedimensional simulation model was established,and DPF was carried out at different altitudes during soot loading and particle regeneration.The performance simulation study and prediction and optimization of DPF performance by response curve method,the research results are as follows:(1)By studying the emission characteristics of the WHTC transient test cycle,the emission data of different altitudes are analyzed.The results show that in the plateau environment,the transient emissions of the engine are worse than the plain,especially the NOX and soot emissions,of which 80 kPa NOX The emission is about 50% higher than 100 kPa,and the soot emission is about 4 times that of 100kPa;a WHTC cycle can load about 1.2g of soot in the plateau;The DPF soot is continuously loaded,and the pressure difference between the inlet and the outlet of the DPF is gradually increased.During the period when the carbon load is from 0 to 4.5 gL-1,the DPF pressure drop increases rapidly,and then gradually becomes slower,and the average is 80 kPa.The loading pressure drop is 8% larger than 100 kPa.(2)Using the test bench and the self-made DPF carrier temperature test system,the regeneration performance of DPF under different altitude conditions was studied by manual controlled regeneration.The results show that in the plateau environment,with the rise of regeneration temperature High,the peak temperature of the DPF carrier increases,and the corresponding peak time is advanced.The peak temperature is increased by 285 ? when 600 ? is compared with 550 ?,and the peak temperature time is advanced by 20%.Under the same regeneration conditions in the plain,with With the increase of regeneration temperature,the peak temperature increased by 125 °C when 600 ? was compared with 550 ?,and the peak temperature was 34% advanced.The temperature field distribution of DPF carrier was consistent regardless of plateau or plain regeneration.Appears at the axial end of the center of the carrier and the carrier radial temperature gradient is greater than the axial temperature gradient.At different altitudes,the pressure drop during DPF regeneration increases with the increase of regeneration temperature,and the temperature rises,the earlier the pressure drop reaches the peak time;at the same regeneration temperature,the regeneration of DPF The pressure drop increases with the increase of atmospheric pressure.When the regeneration temperature is 550 ?,the peak pressure drop of DPF is 7.7 kPa at 80 kPa regeneration,and 9.5 kPa at 100 kPa,an increase of 23.4%.(3)Through the one-dimensional simulation of GT-power,the soot loading law and passive regeneration ability of diesel particulate traps in different altitudes were studied.The variation of pressure drop loss during diesel engine particulate trap in different altitudes was studied.The variation of the peak temperature of the carrier and the frequency of regeneration show that: due to the increase of automobile particulate matter and NO2 emissions in the plateau environment,the exhaust temperature is higher,the loading speed of soot in the plateau environment is much higher than that in the plain;the DPF in the plateau environment The mass of soot that is passively regenerated is about 9% of the total carbon load,while the plain accounts for less than half of the plateau,only about 4%;At the same altitude,the DPF pressure drop increases with the increase of regeneration temperature;at the same regeneration temperature,the pressure drop loss of DPF increases with the increase of atmospheric pressure.;the time required to regenerate a plateau is about 220 s,while the plain is 241 s,and the regeneration efficiency is about 10% lower than that of the plateau.(4)Using the response surface methodology to study the interaction between different atmospheric pressures,exhaust temperatures and exhaust flow factors.Total carbon loading,capture efficiency,pressure drop characteristics,carrier temperature characteristics during DPF capture and regeneration.And the influence law of regeneration frequency,the results show that the interaction of atmospheric pressure & exhaust temperature factor has a great influence on the soot loading quality and collection efficiency of DPF during loading,and the soot loading quality is related to atmospheric pressure and The exhaust gas temperature decreases and increases.During the regeneration process,the atmospheric pressure & regeneration temperature factor interaction has a greater influence on the peak temperature and regeneration efficiency of the DPF carrier.The peak temperature of the carrier decreases with the increase of atmospheric pressure and the temperature of the exhaust gas.The regeneration efficiency increases with the decrease of atmospheric pressure and the increase of regeneration temperature.The exhaust gas flow has the greatest influence on the pressure drop loss of DPF carrier during loading and regeneration.