Free piston engine

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Pochari Technologies has pioneered a groundbreaking new type of diesel engine designed for widespread use in current diesel propulsion applications, boasting significantly enhanced power density and remarkably improved emission control. The engine is a conventional piston engine where a single cylinder functions as two separate combustion chambers. A single-piston oscillates in a two-stroke cycle, providing compression in the opposing chamber with each power stroke in the opposite chamber. With the same stroke length as a conventional engine, a single cylinder can deliver an equivalent amount of power as two cylinders. By eliminating one set of connecting rods, crankshaft, piston, and cylinder, we can substantially reduce engine weight. The engine is free from a camshaft, valvetrain, and crankshaft, significantly enhancing reliability. As a two-cycle cannot provide vacuum, air must be forcibly drawn in at high pressure using electrically driven high-speed 4:1 pressure ratio turbochargers. In a two-stroke diesel engine, the "blower" or turbo aids in removing as much exhaust as possible at the end of each power stroke and provides the necessary pressure to fill the chamber with sufficient oxygen. The injection system is a conventional common rail setup. The engine block is fabricated from high-temperature 351 Aluminum Alloy. This innovation allows for increased volumetric power density, and most importantly, a gravimetric power density increase by a factor of 170%. This technology will be highly attractive for weight and volume-sensitive applications such as marine propulsion. As the engine operates as a "free piston," rather than utilizing a hydraulic piston, a permanent magnet motor linear generator is used to directly power electric motors which can be connected to each drive axle, eliminating the transmission and providing instant torque at low speed. The lubrication system is proprietary but provides greatly enhanced lubrication over conventional crankcase-fed cylinder lubrication as oil is injected directly underneath the oil ring through multiple small orifices at a constant rate and pressure. A targeted BSFC of below 0.35 lbs/hp/hr has been achieved. Power density is estimated to be approximately 2 hp/lb. CR is 17:1. No EGR and SCR are needed due to stoichiometric operation, enabling conventional platinum monolith TWC technology to reduce NOx by up to 99.95% with the addition of a small amount of hydrogen gas as a reducing agent. The use of synthetic fuel eliminates the need for a DPF since the absence of sulfur and nitrates in synthetic natural gas-based fuel results in little to no PM being generated. Since emissions do not dictate design, we can design the engine solely for power density and efficiency. This engine will greatly exceed all modern diesel emission standards while providing efficient trouble-free service to operators. For further information, please contact Christophe Pochari.