The Scuderi Group’s take on the split-cycle engine--one that splits the usual four stroke piston cycle between two different pistons--has a clever means of exploiting every bit of energy it can gather: a compressed air tank that captures energy that would otherwise be wasted.
The split cycle engine works by splitting four-stroke duties between two complementary pistons connected by a passage. The first piston draws in air on the downstroke and then compresses it (and incoming fuel) on the upstroke. Unlike a conventional engine, the upstroke then forces the fuel-air mixture through a passage into a second cylinder where the ignition and exhaust strokes occur. This splitting of chores allows designers to tune the engine more precisely (particularly on the ignition stroke), extracting better efficiency from it.
The Scuderi engine goes a step further by siphoning off unused compressed air that isn’t needed for the combustion stroke at low loads and storing it in a compressed air tank. Once the tank is full, that air can then be fed directly into the combustion cylinder, allowing the compression piston to stop working for a while. Compared to conventional engines, that’s like getting two of four engine strokes for free. So it’s no surprise that computer models show Scuderi’s design improving fuel economy over its conventional counterparts by 50 percent.