Split cycle
I had never heard of a split-cycle engine before, but today, the Scuderi group, whoever they are, showed off a cutaway prototype of such a motor at the Society of Automotive Engineers World Congress in Detroit.
The engine uses pairs of pistons operating in parallel to split the typical 4-stroke cycle into pairs of two strokes. The first piston handles the intake and compression strokes with only air coming in. As a result, the air is compressed at a ratio of 100:1 before a crossover valve is opened allowing the compressed air to pass over to the power side.(…) Scuderi claims the split cycle process will work with spark ignition as well as compression ignition diesel engines. The first prototype is normally aspirated and Scuderi expects it to get about same fuel efficiency as a similarly powerful conventional Otto cycle engine. The big advantage will be in emissions with dramatic reductions in NOx and HC.(…)Future variants will include turbocharged and air hybrid designs that will allow increased efficiency in addition to the lower emissions. The turbo version could produce up to 135 hp/liter allowing for a much smaller engine without compromising power output. Scuderi is also developing an air hybrid variant that adds a high pressure air accumulator to improve the efficiency of the engine to a level the company claims will be comparable to current gas-electric hybrids at much lower cost.
Speaking of cost, Scuderi claims that in spite of the new architecture, the split cycle engine will cost about the same as a conventional engine of similar output. A diesel version could conceivably significantly less expensive because the complex after-treatment systems could be scaled back or eliminated while still meeting emissions requirements. Scuderi claims to be talking to a number of automakers about licensing the technology and hopes to have a deal within a year to 18 months. Hopefully, a production engine based on this design will be on the road within 3-5 years.
Makes me go all warm and fuzzy inside. My question is will such an engine have the fuel management system of most modern ICE engines, i.e., they cut the fuel supply and work on inertia alone when you don’t press the throttle?
