Semiclosed Cycle Internal Combustion Engine Utilizing Cryogenic Exhaust Solidification for Undersea Applications

Abstract

The paper describes the design, hardware, testing, and performance of a breadboard semi-closed cycle power system proposed for undersea operations by the Naval Undersea Center. The work was performed to prove the feasibility of the system. The system includes a commercially available spark-ignition engine, which operates on natural gas, oxygen, and recirculated exhaust gas, and a specially designed liquid oxygen/excess exhaust gas converter. The converter utilizes heat from dry, precooled exhaust gas to vaporize liquid oxygen and provide oxygen for the engine. While providing heat for liquid oxygen vaporization, the exhaust gas becomes frozen. The well-insulated converter is designed with ample storage capacity for both liquid oxygen and solidified exhaust. Nonoptimized hardware provided reliable airbreathing and nonairbreathing operation. Tests indicate that the approach is feasible for undersea applications.