Preparation And Application Research Of Borderline Catalytic Converter On Vehicle Calibration

The serious influence on environment protection caused by automotive emission, make the state's standard for automotive emission become more and more strict.The stageâ… ,stageâ…¡and stageâ…¢for automotive emission standard were carried out continually.Adding the onboard diagnostic(OBD) system on the vehicle is the crucial difference between stageâ…¢and stageâ…£.As the crucial parts of automotive emission control system and online diagnostic system,the onboard diagnostic system will be widely used on vehicles.One of the OBD's most important jobs is to make sure the catalytic converter is working properly and that the engine isn't polluting.OBD is designed to detect emission problems.When a problem is detected,the Check Engine light comes on and a diagnostic trouble code is stored in the vehicle's powertrain computer.Later,the code can be read using a scan tool to determine the nature of problem.So the catalytic converter which has already deteriorated and disabled was needed for matching the calibration of OBD system on gasoline vehicle.According to evaluation index,monitoring index and verification index,the preparation of critical TWC for gasoline vehicle calibration was conducted by a series of test and verification.Firstly the evaluation index,monitoring index and verification index were set according to the process of testing procedures for critical TWC preparation and the state weather TWC at the critical situation.Among all these,monitoring index is the TWC light-off temperature,and critical TWC light-off temperature is higher than fresh TWC light-off temperature.Evaluation index is the OSC of TWC which below the dozens of milligrams and the signal amplitude of after-Oxygen-Sensor is 60%-80%of pre-Oxygen -Sensor.Verification index is the matching of critical TWC,testing the emission standard,and making the emission standard of HC above 240%-300%,below 400%of limited stageâ…£.Next several testing methods were proposed from the principle of disabled TWC,the performance of engine bench testing,the National Standard.Also the tests including aging test,light-off test,OSC test and vehicle matching verification test were all carried out.The procedures of preparation as follows:The fresh catalyst light-off temperature and Oxygen storage capacity should be tested at first.Then the various stages of accelerated aging test were conducted by the testing equipment FOCAS.Next,the light-off test and OSC test of the TWC,which has already aged in different stages,were carried out at the same condition.The compartment was made between the results and the former date.The process of critical TWC preparation was checked according to the set index and monitoring index.At last the critical TWC,prepared in the test,was added on the vehicle to verify.If the TWC match the testing index,according to typeâ… test procedure,that means it done well.Or repeat the former stage.The thesis is focus on the study which includes the preparation of borderline catalytic converter on vehicle calibratin.The large amount of the testing date and result indicate that an effective method of critical TWC preparation for gasoline vehicle was developed in the paper.The evaluation index,monitoring index and verification index were defined on the process of preparation.The testing result also indicated that the foundation date was supported for the OBD calibration by the critical TWC preparation,also the research was completed by various tests.The theory about critical TWC preparation was provided for technical innovation and further development in this paper.The research of critical TWC preparation for gasoline vehicle and application presented in this paper was creative and practical,has a profound economic future in automotive market,especially suited to the automotive manufacture and research agency.