INTRODUCTION The current trend in step gear automatic transmissions is increasing number of forward gear ratios beyond 6, stabilizing for the moment at 8 to 10 in either transverse or longitudinal applications, [ 1, 2 and 3]. Simultaneously, technologies such as high efficiency gears, pumps, low spinloss bearings, seals and clutches, all coupled with aggressive calibration of shift patterns and early torque converter clutch lockup are being implemented on automatic transmissions to reduce losses and improve overall operational efficiency. Previous research on conventional powertrain matching optimal number of forward gear ratios and transmission technologies have largely only looked at current or near horizon engine designs see [ 4, 5 and 6]. A recent study, [7], have looked at over the horizon engine designs, integrating new technologies for drastically improved performance and what automatic transmissions pair best for fuel consumption on a given regulatory test schedule. In general, the authors have countered that the current trajectory of number of forward fixed gear ratios is unnecessary given the increased torque capability at low engine speeds and wider regions of minimum brake specific fuel consumption, BSFC, fewer forward gear ratios are required, potentially as few as four, see [7]. This study also proposed a new automatic transmission design, however, augmented with some form of parallel electrification to supplement the internal combustion engine. The aim of this investigation is to examine the validity of these claims through a detailed analysis approach considering engines with widely varying performance in a given vehicle application and propose alternative step gear automatic transmission concepts. This investigation has two primary objectives, carried out using analytical methods and focused exclusively on conventional automotive powertrain machinery. The first objective was to determine design parameters for the next generation step gear automatic transmissions that best match the operating characteristics of current and anticipated future internal combustion engine designs based upon industry mega trends. Internal combustion engines will continue to increase torque output while reducing fuel consumption and emissions through mechanical design, controls and added features such as those mentioned by [ 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17, 18]. These future internal combustion engines will have an increase in mean brake torque at lower engine speeds while also achieving lower BSFC over a wider range of engine speeds and brake mean effective pressures, BMEP. Figure 1 graphically highlights this trend in engine design and calibration, largely achieved through changes to valvetrain technology, combustion mechanism, friction reduction, downsizing, turbocharging and direct injection, see [ 8, 9, 10, 11 , 12, 13] for details.Internal Combustion Engine - Automatic Transmission Matching for Next Generation Power Transfer Technology Development in Automotive Applications Darrell Robinette and Tejinder Singh General Motors Co. ABSTRACT Development of the next generation internal combustion engines and automatic transmissions for automotive applications is a mandatory powertrain engineering activity required now and in the coming years to meet forthcoming global emissions regulations. This paper details a preliminary investigation into possible synergies for fuel consumption reduction considering emerging automotive technologies integrated into the next generation combustion engine and automatic transmission architectures. A range of hypothetical gasoline engines were created and paired with a generalized set of step gear automatic transmissions designed to meet the performance requirements of high volume longitudinal full size truck application. These designs were then run through a design of experiments orthogonal array for prediction of fuel consumption on the WLTP test schedule and stand still acceleratio