Scuderi Group released video footage of a naturally aspirated one-liter prototype of the Scuderi engine firing on its own in the laboratory in October, 2009.
Design
Scuderi engines have paired cylinders, each of which performs two of the tasks of a conventional engine. The compression cylinder performs intake and compression. The power cylinder performs combustion and exhaust. Compressed air is transferred from the compression cylinder to the power cylinder through a crossover passage. Fuel is then injected and fired to produce the power stroke. The power cylinder fires just after the piston has begun its downward motion. The Scuderi Group says ATDC eliminates a thermal efficiency shortcoming seen in previous split-cycle engine designs. Firing ATDC in a split-cycle arrangement is claimed to eliminate the losses resulting from recompressing the gas. In a conventional Otto cycle engine, each cylinder performs all four strokes per cycle. This means that two revolutions of the crankshaft are required for each power stroke. The pistons fire every other revolution, while the Scuderi engine fires every revolution. The Otto cycle design convention calls for combustion just before top dead center in order to allow combustion pressure to build.
Claimed advantages
According to Scuderi Group, tests indicate that the Scuderi engine shows gains in efficiency and reduced toxic emissions over conventional four-stroke Otto cycle designs. The company also says that the Scuderi engine could be used as part of an air hybrid system, allowing recovered braking energy to be stored as compressed air. Laboratory tests of the prototype are said to match earlier predictions generated by computer models.
Disadvantages
As can be seen, this engine requires an extra valve per pair of cylinders compared to an Otto engine, but only when in air hybrid configuration. In the standard configuration conforming to the schematic above it could use actually one less valve per cylinder pair than an Otto engine. It also has the same power density, even though the power cylinder fires on every rotation, because of the extra compression cylinder. While its fuel efficiency and other advantages may make this a useful modern design, the extra complexity would historically have favored the Otto design, when precision machining was more expensive than fuel savings over the engine's lifetime.
Lawsuits and investigation by the SEC
On March 5, 2015, Hino Motors Ltd, a subsidiary of Toyota, filed suit against Scuderi Group in the United States District Court for the District of Massachusetts for breach of contract and other violations. Hino has accused the Scuderi Group of operating a Ponzi scheme by refusing to refund Hino's $150,000 investment and promising to repay it eventually with money they plan to receive from other investors. On March 13, 2015, Federal Judge Mark Mastroianni allowed Hino Motors to maintain a hold that they have on a $68,000 Scuderi Group bank account. The Securities & Exchange Commission has also investigated the Scuderi Group for multi-million dollar payments to family members, and a separate investor has also filed federal suit against the Scuderi Group. Since 2015, various other investors have also sued Scuderi, which typically settles out of court..
Patents
As of August 2011, Scuderi Group said its patent portfolio included more than 476 patent applications worldwide, more than 154 of which have issued as patents in more than 50 countries.
Partners
The Scuderi Group has partnered with several automotive engineering companies to assist with engineering the Scuderi engine's complementary components. German automotive supply company Mahle GmbH is working on the pistons, Swedish engine developer Cargine Engineering AB is assisting with the air-activated valves, Denver-based Gates Corporation is engineering the belts, and Germany-based Schaeffler Group is contributing to the valve train assembly. The engineering division of Germany's Robert Bosch GmbH is working on the timing mechanism of the engine.
Agreements
Various manufacturers, including Honda, Daimler AG, Fiat, and PSA Peugeot Citroën, have signed non-disclosure agreements with Scuderi Group. A Daimler AG scientist familiar with the matter told The Wall Street Journal that the design has potential.
Regenerative braking
is achieved by connecting an air reservoir to the crossover passage. During braking, energy is stored in the form of compressed air for later use.
Performance
The predicted best brake specific fuel consumption when turbocharged is 233 g/kWh at 1400 rpm, and in the same configuration the engine has a specific power output of 75 kW/litre at 4000 rpm. In naturally aspirated form the BSFC is 269 g/kWh and specific output is 30 kW/litre.
