474 IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY , VOL. 15, NO. 3, MAY 2007 Control of Integrated Powertrain With Electronic Throttle and Automatic Transmission Daekyun Kim, Huei Peng, Shushan Bai, and Joel M. Maguire Abstract— A process to design the control strategy for a vehicle with electronic throttle control (ETC) and automatic transmissionis proposed in this paper. The driver’s accelerator pedal positionis interpreted as a power request, which is to be satisfied by co-ordinating the transmission gear shift and the throttle opening inan optimal fashion. The dynamic programming (DP) technique isused to obtain the optimal gear shift and throttle opening whichmaximizes fuel economy while satisfying the power demand. Theoptimal results at different power levels are then combined to forma gear map and a throttle map which governs the operation of theintegrated powertrain. A control architecture concept is presentedwhere the relationship between the accelerator pedal position andthe power demand level can be adjusted according to the prefer-ence of the vehicle performance target. Simulation, vehicle test,and dynamometer test results show that the proposed integratedpowertrain control scheme produces power consistently and im-proves fuel efficiency compared with conventional powertrain con-trol schemes. Index Terms— Automatic transmission, dynamic programming (DP), electronic throttle control, gear shift map, integrated power- train control. I. I NTRODUCTION IN conventional vehicles powered by gasoline engines, the accelerator pedal actuated by the driver is mechanically linked to the engine throttle which regulates the airflow to theintake manifold. When the driver holds the accelerator pedal constant, the power and torque generated by the engine will change with engine speed, and thus, the driver needs to varythe pedal position to obtain constant torque (acceleration) orpower from the engine. Since each powertrain has its own torque/power characteristics, drivers bear the responsibility to adapt to the powertrain, instead of the other way around. Themechanical linkage between accelerator pedal to the throttleis replaced by an electronic connection, commonly known as electronic throttle control (ETC) [1], [2] in modern vehicles. ETC provides flexibility between the pedal to throttle mappingand, thus, a new design degree-of-freedom. For example, it Manuscript received October 30, 2006; revised January 8, 2007. Manuscript received in final form January 25, 2007. Recommended by Associate Editor K. Butts. This work was supported by General Motors Powertrain. D. Kim was with the Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109-2121 USA. He is now with Research and De- velopment and Strategic Planning, General Motors, Warren, MI 48090-9055 USA (e-mail: andrew.kim@gm.com). H. Peng is with the Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109-2121 USA (e-mail: hpeng@umich.edu). S. Bai is with the General Motors Powertrain, Ypsilanti, MI 48197-0935 USA (e-mail: shushan.bai@gm.com). J. M. Maguire is with the General Motors Powertrain, Pontiac, MI 48340- 2920 USA (e-mail: joel.m.maguire@gm.com). Digital Object Identifier 10.1109/TCST.2007.894641can be used to realize and integrate features such as idle speed control, cruise control, adaptive cruise control, traction control,etc. In this paper, we investigate an integrated powertrain con-trol feature, which coordinates the control of transmission (gear shifting) and engine (throttle). The design goal is to satisfy the driver’s power demand while optimizing fuel economy. For modern powertrain systems equipped with ETC, many studies explored the possible advantage of controlling the throttle opening angle during a gear shift. In [3], Ge et al. present a control algorithm to minimize the reduction in ve-hicle performance and deterioration of shift quality due to thesudden change of the gear ratio. Using a closed-loop control schem