Analysis Of Performance And Regeneration Process On The Diesel Particulate Filter

From proposeing the principle of diesel engine to the current one hundred years,thediesel engine technology is developed comprehensively,as its good performance in power,economy and reliability,diesel engine is widely used in a variety of mechanical devices,especially as a vehicle power.Compared with the gasoline engine, HC and CO of dieselengine emissions is very low, NOx emissions in a considerable level, but the particulateemissions of diesel engine is about 3080 times than gasoline engine.Therefore, it can be seen that the main emissions from diesel engines is PM and NOx.As a result of thecontradictions in PM and NOx formation mechanism, to improve the combustion process ofinternal combustion engines will reduce particulate generation, but will increase thegeneration of NOx?when the emissions limits is less and less,the contradiction is moreprominent, and it bring about certain difficulties in purification of diesel machine.Therefore,in order to reduce PM and NOx emissions simultaneously,we must combine the externalpurification technology.Through comparative analysis of various techniques, it was putforward that particulate trap technology is the most effective technology in controlingparticulate emissions of diesel engine.And the regeneration technology of particulate trap isthe key of application to success.This article focuses on the the performance and regeneration process of particulate filterin the FAW CA6DL235E3,it is a common rail diesel engine with turbocharg and electroniccontrol systerm.Experiment is based on the EGR + DPF (exhaust gas recirculation plusParticulate Filter)technology roadmap.In order to reduce diesel engine emissions,it is basedon exhaust gas recirculation,suppressing NOx emission in machine,captureing the particlesoutside the machine by diesel particulate filter (DPF). The impact of DPF / FBC to engineemissions was researched,as well as the rule of particles loading and regeneration,the impactof EGR system owing to the load of particulate filter was investigated.Study in the loading and regeneration of particulate trap.Research setting ESC test cycle A speed,170N.m torque was the load condition for the particles, and the particles can not becombustion under the conditions,so particles was accumulated rapidly in DPF.The pressurebetween the engine and DPF was increased continuously with the engine running.Theexperimental results show that the load time is about 12.5h when DPF is full load.Particulate loading is slow in initial stages, with the backpressure increased, particulateloading becomes faster.In the particles regeneration of ESCA condition and the range ofactive temperature regeneration, the inlet temperature of DPF is higher, the timeconsumingparticulate regeneration is shorter.The regeneration time of 500℃regeneration temperatureis less than 400℃by almost 1min.Study in DPF internal temperature and the balance point temperature and theevaluation of the reliability in regeneration.In the regeneration stage, there is a highestcombustion temperature in the DPF export position of the axis and it is more than 100℃compared with the peak temperature of entrance.The maximum temperature is decreasedwith the extension of radial direction,the peak temperature is reduced about 80℃in thedistance from the axis 2 / 3 of shaft position.In addition to 1100r/min speed condition whenthe balance point temperature does not exceed 200℃,the balance point temperature in theremaining test speed condition are all over 400℃.In ESC13working conditions,with the exception of lowload conditions where the particulate is not easy be regenerated,theparticulate can be regenerated in the higher load conditions.Based on the weight distributionof ESC test conditions,the ratio of weight in renewable and nonrenewable is 9:10,it isgreater than the ratio of the limit regeneration and the load time with the FBC.Therefore,thetested engine can be achieved the reliable regeneration adding the FBC.Study in the impact of the particulate emissions and other air emissions with DPF inESC13 conditions.FBC were added in 0 # diesel oil and Europe 4 diesel in thisexperiment,according to the law of ESC13 to carry out emissions test,measureing andcompareing the emissions before and after the DPF diesel.The experimental results showthat the particulate volume measured using EU4 diesel is large more than using 0 # diesel inall entry and exit conditions DPF.The conversion efficiency of DPF particulate is 66% using 0 # diesel oil,while the conversion efficiency is 90% using Europe 4 diesel oil,particulateemissions achieve to EU 4 emission limits.NOx,CO and HC emissions tested in entrance andexit of DPF was not significant.In addition, there is a little effect on gas emissions addingFBC to different diesel.Study in the impact of DPF load volume to EGR rate and engine performance.To studythe impact of DPF to EGR systems,a butterfly valve was installed in the exhaust pipe of thediesel engine.It is generated the needed back pressure by controlling the opening of theButterfly valve,simulated the exhaust back pressure generated by trap,to explore the effectsof EGR rate in different DPF load. Experimental results show that changes in exhaustbackpressure as a result of the different DPF load in different conditions will cause thedistortion of EGR rate,the EGR rate of distortion will increase with the load and speedreduction,and will affect the NOx and smoke emissions. At the same time, when the DPFload is larger(more than 50% load), the impact of DPF back pressure on the power and fuelconsumption rate is also larger.So applying EGR technology to reduce Nox emssionmachined with DPF purification technology is an important research field,but the distortioncorrection is a big problem to be solved.