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Scuderi Split-Cycle Engine Consortium targeting direct-injection diesel, natural gas development

The newly formed Scuderi Split-Cycle (SSC) Engine Consortium is having its first meeting at Southwest Research Institute (SwRI) in San Antonio, Texas on 23 January. The SSC consortium currently comprises the Scuderi Group, SwRI, Hino Motors (earlier post) and two suppliers, according to Stephen Scuderi, vice president of the Group.

The SSC Consortium—a two-year project—has two initial goals, said Scuderi. The first is to build a 150 to 250 kW split-cycle diesel research engine with air-hybrid capability (earlier post); the second is the development of a stationary research generator fuel by natural gas with compressed air energy storage capability (earlier post) for stationary applications.

The basic Scuderi Engine is a split-cycle engine—it divides the four strokes of the Otto cycle over a paired combination of one compression cylinder and one power cylinder. Intake air is compressed in the compression cylinder and transferred via a gas passage to the power cylinder for combustion. The company’s prototyping and simulation work to date has been on a spark-ignited gasoline (Otto) platform.

The air-hybrid configuration adds a compressed air storage tank to the engine. Essentially, the air tank stores energy in the form of compressed air, and reuses the air to enhance the combustion process. By turning off the power cylinder during a regeneration event such as braking, and diverting the flow of compressed air to the storage tank, the momentum continues turning the engine, thereby compressing air and storing it in the tank for later use.

From Scuderi’s point of view (consortium members may have their own directional plans), a positive outcome would be to concentrate the first year of the consortium’s work on utilizing existing equipment already at SwRI and modifying it appropriately to be able to explore fuel injection and combustion processes for diesel and natural gas.

If we prove those out and prove the hybrid capabilities, we can accomplish a lot in the first year.

—Stephen Scuderi

The second year would build on the research of the first.

The main OEM in the consortium is by far Hino. We are excited to have them, for a number of reasons, not least of which is the expertise that they bring to the table. We also think that their size of vehicles—medium to large trucks and buses—is an excellent platform for the use of air hybrid technology.

Primarily this is because the larger the vehicle you get this technology into, the more the advantages come into play. The air tank can store large amounts of energy for much more cost effectively than a battery as it grows in size. For that reason, we’ve always wanted to have the engine simulated and then installed in a large vehicle like a truck or a bus. We know that Hino has dabbled in using electric hybrid engines—they are not afraid of taking a look at air hybrid.

—Stephen Scuderi

The genesis of the SSC Engine Consortium was SwRI—a long time partner of the Group for simulation and development work on the Scuderi engine (e.g., earlier post), as well as the operator of a number of engine technology consortia now and in the past, Scuderi said.

They [SwRi] encouraged us to look into it. From there we did our research. It’s a good way to get involvement from OEMs we have looked to in the past in a way that commits them significantly to working with us and keeps the cost down. The advantage to the consortium is that it shares the intellectual property among all the members of the consortium. A joint venture is more expensive for an OEM, a consortium less expensive.

—Stephen Scuderi

That noted, Scuderi said that there are other OEMs interested in the development of the gasoline split-cycle engine; these are interested more in direct joint ventures, Scuderi claimed.

Results of the SSC Consortium’s work will be published either during the two-year project period with the members’ consent, or within two years after the completion of the work, Scuderi said.



Right, when they finis their work we will have an economically viable battery.


In 2064 then...

Roger Pham

Actually, LiFePO4 batteries are good enough for practical PHEV, and that's all we need. ICE technology with turbocharging at 1hp/10cc allows for very small ICE range extender of 750cc-1000cc to help reduce weight and allowing more internal space for luggage and normal seating.

Diesel technology, especially those that use gasoline in diesel engine with controlled reactivity and premixed CI is also very advanced that can achieve above 50% BTE. With turbocharging and electric turbocompounding to harness more exhaust energy, Atkinson cycle is not necessary for heavy duty applications.

Scuderi engine allows for air hybrid, but electric hybrid technology is so good and reliable that is hard to beat. Air hybrid is not nearly as efficient and may be not as reliable as electric hybrid.


The Scuderi cycle is interesting but I think they should try to finish their work on the gasoline version (at least on the conceptual level) before jumping onto something completely different, such as a diesel version. I envision a number of challenges in the combustion field, among other things, that would only make it more difficult for them. Presumably, they go for the money.


It surprises me that they still haven't joined up with Transonic Combustion.  The combination of injection-ignition and the inherent turbulence and mixing of air pushed through a crossover passage appears to be a marriage made in heaven.

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