변형된 듀얼클러치 변속기의 동적성능해석

Abstract

Recently, environmental and energy problems have forced automobile manufacturers to improve vehicle’s dynamic performance and fuel efficiency. DCT(dual clutch transmission) can be solution as an alternative. This study proposes the MDCT(modified dual clutch transmission) based on conventional 6 forward and 1 reverse speed DCT with increased numbers of speed gears for various power flows while minimizing the volume change. This proposed MDCT has 7 forward and 2 reverse speed gears with 18 power flows. The axial length and the number of synchronizers are unchanged as compared with the conventional DCT. To investigate whether the proposed MDCT properly functions, the powertrain components are modeled and computer simulations are conducted for the vehicle equipped with proposed MDCT. The powertrain model consists of the engine, DMF(dual mass flywheel), dual clutch, transmission, synchronizers, drive axle, tire and road load. Engine is modeled using engine map. The dynamic equations of motion for other powertrain components are derived using bond graph method. In the case of gear box modeling, the steady state and transient state characteristics are considered. The three shift schedule modes (power, normal, economic) are developed and applied for the gear shift of the proposed MDCT. Computer simulator is then developed by modularizing powertrain components model based on MATLAB/SIMULINK. The simulation results show that the proposed MDCT does not show torque interruption and acts normal dual clutch mechanism as conventional DCT. The simulation is conducted to investigate the dynamic performance and gear shift characteristics from 0 to 100km/h virtual driving under the three shift schedule modes. To investigate the duration of gear positions during the driving cycles and the fuel efficiency characteristics , Japanese 1015 and NEDC driving schedules are used.; 최근 자동차 산업에서는 강화되는 환경규제로부터 동력성능과 연비 향상이라는 목표를 달성하기 위해 많은 노력이 진행 중이다. 본 연구에서는 동력성능과 연비 측면에서 우수성을 나타내는 듀얼클러치 변속기를 연구대상으로 하여 부피변화를 최소화하면서 다단화를 달성할 수 있는 방안을 모색하였다. 연구대상은 기존 전진 6단 및 후진 1단을 가지는 듀얼크러치 변속기이며, 기어배열의 변경을 통해 전장길이와 싱크로나이저 수의 변화 없이 18개의 동력전달경로를 포함하는 전진 7단 및 후진2단의 변형된 듀얼클러치 변속기를 제시하였다. 제시된 변속기가 정상적인 작동을 할 수 있는지 검증하기 위하여 파워트레인 모델링을 수행하였으며, 컴퓨터 시뮬레이터를 구성하여 변형된 듀얼클러치 변속기를 장착한 가상의 차량이 모의 주행을 실시하였다. 파워트레인은 엔진, 듀얼 매스 플라이 휠, 듀얼클러치, 변속기, 싱크로나이저, 드라이브 액슬, 타이어, 주행저항으로 구성하였다. 엔진은 엔진맵을 이용하여 모델링하였고, 그 외 파워트레인 구성요소는 본드그래프를 이용하여 각각의 메커니즘을 운동방정식으로 유도하였다. 특히 변속기 기어박스의 경우 정상상태와 과도상태에서의 특성을 고려하여 운동방정식을 표현하였다. 또한 3가지의 변속스케쥴(파워, 노멀, 이코노믹)을 마련하여 모의주행 중 변형된 듀얼클러치 변속기가 각 변속스케쥴의 특징에 따라 변속을 수행할 수 있도록 하였다. 컴퓨터 시뮬레이터는 MATLAB/SIMULINK기반으로 개발하였으며 파워트레인 구성요소들의 운동모델을 모듈화하여 구성하였다. 시뮬레이션을 통해 변형된 듀얼클러치 변속기가 동력단절을 발생시키지 않으며 변속 중 정상적인 듀얼클러치 메커니즘을 가진다는 것을 확인하였다. 또한 0 to 100km/h 성능평가를 통해 변형된 듀얼클러치 변속기를 장착한 차량의 동적성능과 변속특징을 확인하였고, 3가지 변속스케쥴에 따른 차이를 분석하였다. 마지막으로 fuel efficiency에 대한 평가를 위해 Japanese 1015와 NEDC driving cycle을 모의주행 하였고, 전체 주행시간 중 사용되는 gear position의 duration과 fuel efficiency의 특징을 확인하였다.|Recently, environmental and energy problems have forced automobile manufacturers to improve vehicle’s dynamic performance and fuel efficiency. DCT(dual clutch transmission) can be solution as an alternative. This study proposes the MDCT(modified dual clutch transmission) based on conventional 6 forward and 1 reverse speed DCT with increased numbers of speed gears for various power flows while minimizing the volume change. This proposed MDCT has 7 forward and 2 reverse speed gears with 18 power flows. The axial length and the number of synchronizers are unchanged as compared with the conventional DCT. To investigate whether the proposed MDCT properly functions, the powertrain components are modeled and computer simulations are conducted for the vehicle equipped with proposed MDCT. The powertrain model consists of the engine, DMF(dual mass flywheel), dual clutch, transmission, synchronizers, drive axle, tire and road load. Engine is modeled using engine map. The dynamic equations of motion for other powertrain components are derived using bond graph method. In the case of gear box modeling, the steady state and transient state characteristics are considered. The three shift schedule modes (power, normal, economic) are developed and applied for the gear shift of the proposed MDCT. Computer simulator is then developed by modularizing powertrain components model based on MATLAB/SIMULINK. The simulation results show that the proposed MDCT does not show torque interruption and acts normal dual clutch mechanism as conventional DCT. The simulation is conducted to investigate the dynamic performance and gear shift characteristics from 0 to 100km/h virtual driving under the three shift schedule modes. To investigate the duration of gear positions during the driving cycles and the fuel efficiency characteristics , Japanese 1015 and NEDC driving schedules are used.