COMMON BORE ENGINE PHILOSOPHY FOR FUTURE POWER-PACK CONFIGURATIONS

This paper discusses the packaging characteristics of a family of power-packs for military land vehicles in the 21st century. 3 classes of vehicles are considered: light vehicles (300 600 Hp), medium weight vehicles (600-1000 Hp) and heavy vehicles (1000-1500 Hp). The paper highlights that a common bore engine approach provides both very good performance and a very compact power-pack. 2 different engine styles are examined. The results are expected to be applicable for a spectrum of modernized engine platforms that would employ a common bore engine approach. The approach offers many product development and production advantages, including lower development and tooling costs, and reduced product inventory needs, lead times, development costs, in addition to reduced product development risk. Various trade study parameters are considered in addition to engine power. Power-pack configurations based on a common bore approach shows significant commonality advantages and manufacturing efficiencies across the future family of engines horsepower classes. The common bore engine approach also demonstrates that a significant reduction in power-pack space claim can be achieved, while still retaining all of the development, production, and, maintenance advantages . INTRODUCTION The US Army Tank Automotive Research, Development, and Engineering Center (TARDEC) has expressed the desire to develop an engine ‘family’ that would be suitable across the range of tracked military vehicles, ranging from 300 – 1500+ Hp regime[1]. The perceived advantages of a common engine family are reduced product development cost and time. A common engine family would also have reduced life cycle costs after production owing to commonality in spare parts, maintenance and repair tools, training and repair procedures. A challenge with executing the concept is identifying the critical features of an engine that would optimize the advantages of a common engine family without significantly compromising the potential disadvantage of instituting a common engine family philosophy – performance and packaging. In this investigation, a review of the performance characteristics of a common bore engine for military applications is presented, along with identifying packaging sensitivities and other critical parameters. The investigation was performed with 2 different engine types for exemplary purposes, but would be applicable for any engine type. For investigative purposes, the application of the family of engines for military vehicle applications was divided into 3 different categories:  Light vehicles in the approximate range of a 300600 Hp engine class.  Medium weight vehicles in the approximate range of a 600 – 1000 Hp engine class  Heavy weight vehicles in the approximate range of a 1000-1500 Hp engine classification Proceedings of the 2014 Ground Vehicle Systems Engineering and Technology Symposium (GVSETS) COMMON BORE ENGINE PHILOSOPHY FOR FUTURE POWER-PACK CONFIGURATIONS This document consists of general capabilities information that is not defined as controlled technical data under ITAR Part 120.10 or EAR Part 772. Page 2 of 9 In this analysis of a common family of engines, various considerations are necessary in order to determine the relative merit of the concept. These are:  Resultant Power-pack Density Using a Common Engine Bore Approach. This is a critical consideration for military vehicle applications. Certainly, independently designed engines offer the promise of higher performance – the issue is the extent of the advantage and the added life cycle cost burden associated with an independently designed engine  Engine Life Cycle Cost, including: o Development Advantages o Production Advantages o Maintenance and Repair Advantages These items are addressed in detail in this investigation. Variables in the investigation include engine type, engine bore size, and vehicle size. For consistency, the predictive techniques used to determine performance were consistent with prior investigations [2].