Research And Engineering Application Of Key Technology In Vehicle Exhaust Test Under Driving Mode Condition

Vehicle emission test under driving mode is very important for an accurate assessment of vehicle emission levels and ensurement of the vehicle emissions I/M system,under this testing mode,the simulation and control of working conditions is a key technology.For cleaning up the environment and vehicle emissions control, it is necessary to study deeply the theory and application of the key technologies according to different working conditions.Relying on the Vehicle Thermal Energy and Power Machinery key laboratory,combining with numerical simulation and experimental as the main means, the theoretical and experimental studies of common technologies involved in the control and simulation of working condition in the test under driving mode was carried out,and according to the main working conditions type,study and verification with experiment on the key technologies in the work condition was deeply researched.The main works are:1The principle of the car running on the chassis dynamometer was explained, the dynamics model and power measurement model were analyzed. Vehicle resistance is divided into the speed type resistance and inertial type resistance,and the electrical simulation model of the vehicle resistance on the chassis dynamometer was founded.The principle of inertia simulation with electronic mode is analyzed.and the control strategy of the inertia simulation in the automotive test,calculation and evaluation way of the simulated inertia were proposed,and then the verification experiment was designed and realizeed.2Characteristic of the eddy dynamometer used in the test under driving mode is analyzed,based on the nonlinear,time-varying characteristics,a complex identification,which adopt the subspace method for initial identification and use the least squares prediction error method for parameter optimization, is proposed.the correctness of the model was verified by the corresponding test in the Chinese stabdard.And then a basis for the design of the simple steady-state test methods was provided.3According to ASM test characteristics,a composite control strategy with transition section adaptive and steady-state PID control is put forward,in the transition,adaptive control with the improved RLS model was adopted,and then the steady-state use the PID control,in which the PID control parameters was tuned with the model obtained by the identification in the the transition,based on the simulation algorithms with Matlab.the ASM control program was designed with C++builder6.0as the development platform.Based on the idea of weighting conditions,a evaluation indicators and methods for the simulation of the ASM test was proposeed.and then experiment was carried out to verify the control strategies and evaluation methods.4State space model with speed parameters under the VMAS test was established,and the speed and acceleration signals was processed by Kalman filtering and strong tracking adaptive Kalman filter algorithm with forgetting factor.And the process effect was verified in the accelerated,constant speed,deceleration conditions.The results show that the calculation accuracy of the acceleration was greatly improved.5According to the feature of VMAS,the LS-SVM model for the eddy dynamometer was founed,and then the LS-SVM model is linearized to suit for GPC control. The VMAS torque controller with smart generalized predictive control was designed,based on laboratory equipment,the test software was programmed,and then the experiment was carryied out,test results show that the control accuracy of the system meet the VMAS the test requirements.6In transient mode emission test,the induction motor system with variable frequency drive was studied.Based on the analysis of principle of the direct torque control,the simulation model of the DTC control was founed,and then the response performance was analyzed by the simulation test.The virtual simulation system with car-electric dynamometer was founed,based on this platform,the four-quadrant performance and inertia simulation performance was studied,thus a basis for performance improvement of the dynamometer is established.