Split-Cycle enginesSplit cycle engines—engines that split the functions of a normal four-cycle piston into two separate but adjacent and complementary pistons—have never been able to match the efficiency and overall function of traditional internal combustion engines, but a new design could change all that.

By tweaking the standard split-cycle design with new features like a compressed air tank that captures wasted energy from the system, the Scuderi Group claim not only to have matched the efficiency of the standard four-cycle engine, but to have far surpassed it.

Split-Cycle engines2

The Scuderi Group’s design has drawn interest from nine major carmakers, the company says, but has yet to prove the technology in real world prototype tests. But in computer simulations that install a Scuderi engine in a 2004 Chevy Cavalier, the split-cycle engine shows to reduce fuel consumption by 25 to 36 percent, translating roughly to a 50 percent improvement in overall fuel economy.

The engine does so by tweaking old split-cycle designs to be more efficient and to trap wasted energy so that it can be fed back into the system. Traditional four-cycle engines have four piston strokes: a down-stroke that pulls air into the cylinder, a compression up-stroke that compresses air (and fuel) in the cylinder, a combustions stroke in which the fuel and air is ignited and turned to kinetic energy, and another up-stroke in which the exhaust is cleared from the cylinder.

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