Light-weight Vehicle Exhaust System for Amphibious Vehicles

A major challenge facing designers of exhaust and thermal management systems is to increase exhaust transport, heat transfer and dissipation capability, while reducing weight penalties and improving component lifecycle. Currently, the demand for increased exhaust and heat removal in military vehicles is surpassing the performance limits of conventional exhaust and thermal management systems. The main reason is updated military vehicles include additional armor protection, sensors, firepower, and other advanced capabilities that have added weight and higher performance requirements on the system components. The USMC experienced exhaust system challenges on the Expeditionary Fighting Vehicle (EFV). The aluminum and composite design developed to meet the exhaust requirements of the 2800 hp diesel enginepeformed poorly and came at a substantial weight and cost penalty. As the USMC begins to look at future amphibious assault vehicle (AAV) designs, it is seeking to develop a light-weight, lower-cost vehicle exhaust system that can withstand the repeated heating/cooling cycles under exposure to the aggressive saltwater environment, while minimizing the transfer of heat from engine exhaust to the external surface of the vehicle for improved personnel safety and reduced thermal signature. METSS proposes to achieve these objectives using an exhaust system concept based on a composite wall construction, where each material used in the composite design is selected to perform a specific function. METSS believes this approach offers the most flexibility with respect to the overall design of the exhaust system, providing multiple ways to address the demanding thermal, structural, and environmental performance requirements.