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A small-scale flow rig has been constructed to investigate the swirl behavior of various intake manifold configurations. This effort is to support the development of a 10cc-size, single-valve reverse uniflow 2S engine. In this reverse uniflow geometry the incoming charge enters through a single valve in the engine head, and the burned gases are exhausted through symmetrically-arranged ports in the cylinder wall near bottom dead center. Port-directioning of the fresh charge, used in conventional (bottom-up) uniflow arrangements, is not available with this geometry, so another means to control the cylinder sweeping is sought. The flow rig has been constructed on a 2:1 scale, and three preliminary intake manifold configurations have been prototyped using a 3D printing machine. A straight manifold, a ramped tangential manifold and a basic helical design were manufactured.

A 10cc single-valve, reverse uniflow 2S engine is being developed to power a compact compressor system; the output from this device could be hydraulic or pneumatic power. In this design a free piston is used to directly compress the power fluid. In the initial configuration fresh charge will be delivered through a single, dual-acting spring-loaded poppet valve located in the center of the cylinder and the burned charge is exhausted through symmetrically-arranged ports located at the bottom section of the cylinder; two combustion chambers exist on opposite ends of the piston. Of particular interest in the early stages of the engine development is the gas transfer system; proper cylinder scavenging is required to ensure adequate engine operation. An initial design is being investigated using the commercial computational fluid dynamics software suite, STAR-CD/ESICE. This report will document some initial simulations and indicate areas requiring further refinement.

Of late there has been a resurgence in studies investigating parameters that quantify combustion knock in both standardized platforms and modern spark-ignition engines. However, it is still unclear how metrics such as knock (octane) rating, knock onset, and knock intensity are related and how fuels behave according to these metrics across a range of conditions. As part of an ongoing study, the air supply system of a standard Cooperative Fuel Research (CFR) F1/F2 engine was modified to allow mild levels of intake air boosting while staying true to its intended purpose of being the standard device for American Society for Testing and Materials (ASTM)-specified knock rating or octane number tests. For instance, the carburation system and intake air heating manifold are not altered, but the engine was equipped with cylinder pressure transducers to enable both logging of the standard knockmeter readout and state-of-the-art indicated data.