| Since entering the 21 st century,intelligence,safety,energy conservation,and environmental protection have become the main theme of the development of the world’s automobile industry,which requiring that automobiles achieve higher fuel economy and emission targets while meeting the driving maneuverability and power performance.The automatic transmission system plays a decisive role in improving the power,economy,driving maneuverability and driving safety of the vehicle.Dual Clutch Transmission(DCT)is the most advanced transmission product in the world today.It is an advanced automatic transmission that uses a dual clutch and shift control mechanism to achieve automatic transmission shifting.As a core technology of the DCT control system,the gear decision technology plays a vital role in the performance of the vehicle power and fuel economy.This paper takes a passenger car equipped with a DCT as the research object.In order to improve the vehicle fuel economy,ride comfort and active safety performance.The gear realtime optimization and intelligent decision technology for DCT was studied.The main research work was carried out as follows:(1)The simulation model of the vehicle system was established based on Matlab/Simulink,which provides a simulation platform for the research of DCT gear real-time optimization and intelligent decision technology of the dual-clutch automatic transmission.In addition,the traditional two-parameter shift schedule for dual-clutch automatic transmission was established,including the optimal dynamic shift schedule,the optimal economic shift schedule and the comprehensive shift schedule,which provide the theoretical basis for the optimization of the shift sequence and the formulation of the DCT intelligent gear decision technology.(2)For the purposes of better fuel economy and better vehicle driving performance,a dynamic programming model for the gear real-time optimization of DCT was established by using Dynamic Programming(DP)optimization method,and the optimal shift decision sequence of the DCT vehicle under the NEDC cycle was calculated.Comparing with the traditional two-parameter shift schedule,the results show that the total fuel consumption of the vehicle with the optimal gear decision sequence based on the dynamic programming optimization method was reduced by 5.43%,On the premise of not affecting the vehicle power performance,the number of shifts of the vehicle was effectively reduced,and the fuel economy of the vehicle has been improved.(3)The fuzzy control method was used to identify the driving intention.The Extended Kalman Filter(EKF)algorithm was used to identify the vehicle quality and the road slope in real time based on the theoretical analysis the vehicle longitudinal dynamic model.On the basis of the identification of the driving intention and the driving condition of the ramp,the intelligent gear decision technology of the DCT was formulated.The simulation results of the vehicle shift performance under the control of the intelligent gear decision technology and the dynamic planning shift schedule were compared and analyzed,which have been proved that the intelligent gear decision technology could effectively solve the problem of vehicle shifting under the running condition of ramp.The vehicle driving comfort and active safety performance also have been improved.(4)A bench test platform for the DCT was set up.By comparing and analyzing the bench test results and the simulation results,it was shown that the vehicle with the gear position optimization strategy fuel economy was improved based on ensuring the vehicle power performance.At the same time,the intelligent gear decision technology based on driving intention and driving condition recognition could effectively solve the frequent shifting phenomenon of the vehicle,and the ride comfort and driving safety of the vehicle has been improved,which proved that the effectiveness and superiority of the DCT gear real-time optimization and intelligent decision technology. |
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