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Scuderi Group to Present Preliminary Results on Air-Hybrid Study and Update on Scuderi Engine Prototype Testing at Washington Auto Show

The Scuderi Group will present preliminary results from a study underway at independent lab SwRI on the performance and viability of the Scuderi Air-Hybrid (earlier post) at the upcoming Washington Auto Show in Washington, DC. The company will also provide an update on the progress of Scuderi Engine prototype testing at the event. Scuderi Group is in talks with or has NDAs with 14 of the world’s top 20 automakers, according to the company.

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 air-hybrid configuration adds a compressed air storage tank to the engine.

Early computer simulation studies show the Air-Hybrid achieves up to 50% more fuel efficiency than conventional engines while emitting up to 80% percent less toxins than any conventional engine on the road today. It would also be available at a much lower cost than an electric hybrid system.

Scuderi Air-Hybrid Operating Modes. Click to enlarge.

Scuderi Air Hybrid Operating Modes.

  1. Normal Operating Mode: An Air-Tank stores wasted energy in the form of compressed air, and reuses the air to enhance the combustion process.

  2. Regenerative Braking Mode: By turning off the power cylinder 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.

  3. High-Efficiency Mode: By turning off the compression cylinder and utilizing high-pressure air from the storage tank to supply the power cylinder, losses due to compression are reduced to nearly zero when operating in the high-efficiency mode.

  4. Cruising Mode: Only a portion of the compression cylinder’s charge is sent to the power cylinder during cruising mode. The remainder of the charge is sent to the air storage tank for later use. Whenever the air tank is full, the compression cylinder shuts off, and the vehicle operates in high-efficiency mode.

Preliminary Results from Scuderi Air-Hybrid Engine Study
Engine speed Up to 6,000 rpm
Horsepower Up to 140 hp/L
Efficiency (full load) 5-10% higher than conventional engine
Efficiency (part load) 25-50% higher than conventional engine
Emissions: NOx Up to 80% less than conventional engine
Emissions: CO2 Up to 50% reduction compared to conventional engine
Air tank charging to discharge ratio 1:3
Air tank pressure 200 bar
Engine operating pressure 140 bar
Fuel injection pressure Up to 200 bar
Brake Mean Effective Pressure (BMEP) Up to 30 bar
Compression ration 75:1 - Compression side
50:1 - Power side
Displacement (approx. 1L) .48 - Compression side
.52 - Power side



They seem to have something in common with ESStor ESSUs. They both have be promised for the last five years but none are in operation.

Could a combo ESStor ESSU-Scuderi Air Hybrid genset do better?

Henry Gibson

It is rather fun to indulge in the critism of companies that are working for years on proposed inovative projects, and I have enjoyed the fact that Scuderi has made such a good example. The gas turbine engine is an obvious precursor of the Scuderi engine. The air car developed in France is another when it uses fuel to heat its compressed air. One UPS company uses electrically preheated stainless steel plates to put more energy into its compressed air to be ready to supply power to a turbine generator when the grid fails.
In Germany and the US there are two giant hybrid compressed air energy storage units and others proposed.

Most locomotives and large tractor trailers should use a modern computerized version of the Kitson-Still steam locomotive hybrid.

There is no question that hybrid operation of any type for automobiles can even double efficiency.

Plugin hybrids are the ultimate CO2 sparing vehicle. Even cheap lead-acid batteries are suitable for many automobile uses of plug in hybrids. ..HG..



What I wanted to say is that this type of engine has been talked about for a long time (as long as the ESStor ESSU if not longer) but none or very few are in operation.

However, If both materialize (this ICE + ESStor's ESSU) they could make a high performance PHEV.


"Efficiency (part load) 25-50% higher than conventional engine"

This could make a good range extender engine. I still like the air/electric hybrid where the air assist is increased by the heat of the engine.



I don't think so, if you increase the part load efficiency is precisely that you don't want to do to hybrid or range extender. The 50% is still to be demonstrated by the way, as for the 25%, other architectures like direct injection with downsizing can get close to this, even better: variable compression ratio + turbo and downsizing concepts can do better, in clear whatever reduce pumping losses or make use of throttle.


I see your point, but gaining efficiency at partial load would make an engine that is not blasting away at maximum output. No one has mentioned what happens when a range extender engine fires up and pushes to maximum. That is I why I think Fisker put in the 2.0L turbo that puts out 240 hp at 6000 so that it could produce good power at 1500 rpm.

If one of these engines were small enough to just loaf along and produce good power at improved efficiency, then it might be quieter, with less vibration and last longer. I understand getting higher thermal efficiency out of an ICE when running closer to maximum output, but there are other factors to consider. But everyone thinks that they are right, no matter what, so that is where all discussions will stay.


The whole point of the storage portion of the air hybrid is to eliminate the need for electrical components such as batteries and capacitors, and also make it possible to build the entire drivetrain with existing equipment and techniques.

That said, a split-cycle engine with the compression system sized to produce no excess air (no "cruise mode") could be a better sustainer.  The difference between the compression ratio and expansion ratio, plus the lack of heat transfer from the combustion chamber walls to the uncompressed air charge, could give a substantial improvement over the Atkinson cycle.



I think you have concern about the ability of downsized engines to deliver power quietly and reliably, I don't think it is an issue.


Maybe, also the fact that they generate massive turbulence in the combustion cylinder should improve efficiency and clean burning. But this is all good on the paper, they haven't showed anything yet that could materialize it. Let's see what they will report this coming week, though with Scuderi, we are use to a lot of wording for small incremental progresses.


Though not in production, this engine is being used to raise funds.

But the efficiency is much lower than Bernie Madoff.



A more efficient range extender for PHEVs would be valuable for longer trip users.

Long haul trucks, inter-city buses, locomotives, ships etc could benefit from the potential 25% to 50% fuel efficiency improvement.


"I don't think it is an issue"

What do you base that opinion on? Have you heard a range extender engine run? I do not think that people want a range extender engine to be roaring loud, that is just common sense.



Range extender for heavy PHEVs (long haul trucks, inter-city buses, locomotives, ships etc) could have a constant controlled roar as long as they are 25% to 50% more efficient. Current large diesels ICE do.

Nick Lyons

Studies, schumidies.

I once worked for an inventor of new kinds of gears. He was very good at coming up with ideas, filing patents and was pretty good at getting investors to keep his 'business' going. To my knowledge few, if any, of these innovations ever got into production, although many of them probably had real merit.


A lot more fuel goes to US LDVs than US heavy vehicles, and "controlled roars" are still an acoustic nuisance to bystanders.  (I'd like to see a date certain by which diesels which do not use injection strategies to eliminate "diesel knock" can no longer be licensed for public roads.)

The Scuderi engine has a much greater expansion ratio than compression ratio, so it will have less energy in the exhaust pulse and should have less exhaust noise.


As usual, you make no sense in your comments.
The engine is in it's developemental stages and resources (money is needed to produce the final product). The amount of money raised is minimal
compared to the benefits of this new engine technology.
Several OEM's have done their own studies on this technology and also recognize it's potential. Ask yourself this question TT, Why would 14 of the top 20 OEM's even talk to the Scuderi's if there was no real potential there?

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