INTRODUCTION The U.S. Government owns and maintains a large fleet of ground vehicles covering a wide spectrum of mission profiles. The cost to supply each vehicle with fuel during peacetime is staggering and becomes more so under war zone conditions. The fuel represents more than half of the logistics tonnage of the Department of Defense (DoD), and more than 70% of the tonnage required to put the U.S. Army into position for battle [1]. The DoD estimates that 40,000 Army personnel involved in either the distribution or movement of energy [ 2]. Not to mention only two out of the top ten battlefield fuel consumers in the U.S. Army are combat vehicles and the other eight carry fuel and supplies. Over half of the fuel transported to the battlefield is consumed by support vehicles, not vehicles engaged in frontline combat [ 3]. The impact of the vehicle fuel economy in military applications is amplified due to the fact that much of the present logistics support is devoted to moving fuel [4]. It is critical to reduce fuel consumption of those vehicles that play an important role in the U.S. Army tactical vehicle fleet. While hybrid technology has advanced radically over the past decade, the focus has been on integration in passenger cars and light-duty trucks. However, recent fuel cost increases have shifted some of this attention to the medium- and heavy-duty truck market. Hybrid vehicles use dual energy sources propulsion system in which energy is used more efficiently than in conventional powertrains. A standard propulsion system has four primary components: (1) The internal combustion engine (ICE) to supply power for the other vehicle systems; (2) The transmission to control the speed ratio and the level of torque multiplication between the engine and the final drive; (3) The final drive and drive axle assembly to multiply transmission output torque and transfer power to the wheel assembly; (4) The tire and wheel assembly that transfers power from the axle assembly to the ground. To electrifying a vehicle propulsion system, electric machines must be connected somewhere in the power flow. Based on the ratio of electric power to total power of a vehicle, the degree of powertrain hybridization is typically classified into two levels: mild and full (strong) hybrids. The strong hybrid systems enables fuel economy improvements by: (1) Allowing the ICE to be turned off when idling or during periods of low power output - two highly inefficient stages of typical ICE operation; (2) Recapturing waste energy through regenerative braking which can be stored for later use; (3) Providing electric-only driving; (4) Supplying assist during varying power demand. The Crankshaft-Integrated-Starter-Generator (C-ISG) system replaces the conventional starter motor and alternator with a larger electric machine located between the engine flywheel and transmission. A C-ISG system typically utilizes conventional transmissions with significant packaging changes to accommodate the increased envelope of the electric machine [5, 6]. The electric machine in the C-ISG system may be packaged around torque converter (using a ring type motor) such as [7], or between the engine and the transmission where the torque converter is removed, such as Honda IMA system Experimental Assessments of Parallel Hybrid Medium-Duty Truck Y. Gene Liao Wayne State University Molly O'Malley and Allen Quail ASRC-Primus Solutions, Inc. ABSTRACT Fuel consumption reduction on medium-duty tactical truck has and continues to be a significant initiative for the U.S. Army. The Crankshaft-Integrated-Starter-Generator (C-ISG) is one of the parallel hybrid propulsions to improve the fuel economy. The C-ISG configuration is attractive because one electric machine can be used to propel the vehicle, to start the engine, and to be function as a generator. The C-ISG has been implemented in one M1083A1 5-ton tactical cargo truck. This paper presents the experimental assessments of the C-ISG hybr