A Study On Aging Test Of Three-way Catalyst Of The Gasoline Engine Based On FOCAS System

With more outstanding air pollution and more strict emission regulations,the three-way catalyst has been the mainstream technology of emission control of gasoline engine,also for its maturity and dependability.But catalyst will deteriorate after employ chronically.It's really practical to study catalyst's resistance.Using fast aging method can estimate catalyst fleetly and approximately,and can save lots of manpower,material and funds.Producing mechanism of gasoline engine emission and its harm has been described firstly in this paper.After-treatment technology of gasoline engine at home and overseas has summarized,as well as development state of catalyst and its aging cycle.Based on correlative data,structural principle and aging mechanism of the catalyst of gasoline engine,along with relative performance index and evaluation test have been studied;then tests on ARL-102 method ground on FOCAS system has been raised,to judge if the method could be employed in research and development,and performance examine of three-way catalyst in our country.ARL-102 cycle is employed by American Evironmental protection agency,and the cycle last 60 seconds with air/fuel ratio goes four phases.Engine runs stably for 40s at stoichiometric AFR;for 40s at A/F tuning to 13.2 through ECU;then for 10s while jetting the second air in vent-pipe;for 4s again A/F ajust to stoichiometric AFR and that air injection is on,so A/F of the catalyst's intake has been to 16.5.The paper studys ARL-102 cycle on FOCAS system.FOCAS system is developed at Southwest Research Institute,which is consists of five main subsystems;a fasolin-fueled burner capable of continuously operating at stoichiometric AFR,an oil injection subsystem to allow the the introduction of oil in a controlled quantity at any location within the exhaust,a blower,a heat exchanger,and a computerized control system to operate the entire test stand.The burner apparatus was designed to simuluate the flow of exhaust from a four-cylinder engine under a variety of load conditions,allowing full-sized automotive catalyst systems to be aged.The test main include three parts;1.to compare experimental results on different catalysts using ARL-102 cycle:taking 100h aging test of two different catalysts respectively according to ARL-102 cycle on FOCAS system,then contrasting two catalysts' performance after aging,in order to observe whether the cycle may distinguish catalyst level;2.to contrast experimental results on identical catalysts using ARL-102 cycle and fuel cut respectively:taking 100h aging test of two identical catalysts according to ARL-102 cycle and fuel cut cycle respectively on FOCAS system,then contrasting two catalysts' performance after aging,to see deactivation degree of catalysts applying ARL-102 cycle;3.to test aged catalysts on real cars:testing the two catalysts,which have aged according to ARL-102 cycle and fuel cut cycle respectively,on real cars,then contrasting results of two catalysts' emission,so as to study if the conclusion is same as the engine bench evaluation.The test indicate that ARL-102 cycle own good resolving power to distinguish the level of catalysts,moreover it can deteriorate catalysts more seriously than fuel cut,so the method could apply to research and development,and performance examine of three-way catalyst in our country.