Split-Cycle Engine Concept
The new Scuderi Split-Cycle engine design concept promises increased efficiency and reduced harmful NOx emissions compared to the current generation of internal combustion engines found in most cars. Ironically, this new concept is a variation on the notoriously inefficient and polluting 2-stroke engine.
A 2-stroke engine is attractive due to its simple design and high power-to-weight ratio (compared to a 4-stroke or Otto cycle engine), and it powers a range of machines such as lawn mowers, chain saws, snowmobiles, model airplanes, and outboard motors. A 2-stroke engine is problematic due to its incomplete ignition of an air, gasoline and lubrication-oil mixture that releases copious amounts of pollutants such as NOx, carbon monoxide (CO), and un-burnt fuel into the atmosphere.
The new Split-Cycle concept proposed by Scuderi uses an additional piston to compress air destined for the combustion chamber – replicating the crankcase compression technique used by a conventional 2-stroke engine, but excluding polluting lubrication-oil from the air-fuel mixture. Combined with uniquely timed valves to control the inflow of compressed air and outflow of exhaust, Scuderi claims the new concept is not only superior to existing 2-stroke engines, but that it is also more efficient and cleaner than the average 4-stroke engine found in most cars.
Optionally the new Split-Cycle concept can use a form of regenerative braking to recover energy usually lost to heat. By switching over to its compressor mode during braking the engine can charge a compressed air reservoir. During acceleration or cruising the pressurized air from the reservoir can be released into the combustion chamber (idling the compressor stage), significantly improving overall efficiency.
While there is not yet a working physical prototype of the Split-Cycle concept, Southwest Research Institute used Computer Aided Engineering (CAE) simulation analysis tools such as Computational Fluid Dynamics (CFD) to help Scuderi cost-effectively evaluate the new design concept. On the basis of the simulation analysis, Scuderi filed numerous patents on the Split-Cycle concept and have attracted wide interest in the idea.
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