SwRI simulations indicate Scuderi split-cycle engine consumes 25% less fuel than comparable conventional engine in Cavalier; 36% reduction with hybrid configuration
17 January 2011
Preliminary results from vehicle simulations conducted on a Scuderi split-cycle engine at Southwest Research Institute (SwRI) show that a base, naturally aspirated Scuderi engine (four cylinders—i.e., two split pairs) operating in a 2004 Chevrolet Cavalier would consume 25% less fuel under the FTP (Federal Test Procedure) than the comparable standard gasoline engine, while matching power and torque. A naturally aspirated Scuderi Air-Hybrid configuration consumes 30-36% less fuel under similar drive conditions, the simulations found.
These simulations do not reflect the engine’s new V-design (earlier post), which will improve thermodynamic efficiencies and supports turbocharging (the current design is inline). As a result, said Sal Scuderi, president of the Scuderi Group, there are further significant reductions in fuel consumption possible.
We are confident it is going to get higher. When we ran these simulation, the mapping for our engine was not totally complete. There are certain driving modes of the engine to keep it running at high efficiency. In addition, we didn’s go with the max pressure in the tank [for the hybrid mode]. We will gain further. We expect the efficiencies to continue to climb as modifications are made and new simulations are conducted, including computer modeling of the 2011 Nissan Sentra running with a Scuderi engine.
—Sal Scuderi
The Scuderi engine divides the four strokes of a combustion cycle among two paired cylinders—the left cylinder functions as an air compressor, handling intake and compression, while the right cylinder handles combustion and exhaust. Key to Scuderi’s split-cycle design is that it fires after top dead center. By optimizing the split-cycle concept, the engine when fully developed will reduce NOx emissions up to 80% and improve fuel efficiency by 50%, compared to a conventional gasoline engine, according to the company. The engine requires one crankshaft revolution to complete a single combustion cycle and with is projected to have higher torque, thermodynamic efficiency, and lower emissions than possible with today’s engines.
One of the big advantages of our engine is high resistance to knock. With turbocharging, we can have some huge gains, we can downsize the engine and produce very big power.
—Sal Scuderi
Scuderi said that the newest SwRI simulations resulted from conversation with major OEMs with whom Scuderi is working, who asked the company to come up with a way to simulate the Scuderi engine in their vehicles. SwRI is developing new subroutines for the modelling software to simulate the Scuderi engine in specific OEM vehicles. In the meantime, Scuderi said, it took information available on the Chevrolet Cavalier and used that as the test case to do the first simulation and work the bugs out.
With $65 million in funding to date, Scuderi Group’s business model is to license its technology to qualified engine manufacturers worldwide. The company’s global patent portfolio contains more than 476 patent applications filed and 154 issued in 50 countries. Sal Scuderi said that he expects to be able to announce license deals for the basic technology this year, and speculated that OEMs would then theoretically require two to three years to apply their own tweaks, develop prototypes and introduce their own split-cycle production engines if the decision was made to proceed.
For the same size engine in terms of displacement, [a Scuderi engine] would cost about the same as a conventional engine. Our advantage is dramatic downsizing, especially when you go to turbocharging. We’re confident that with the right configuration, you’d get a slightly lower price [with our engine]. That’s not the usual case with a new technology.
—Sal Scuderi
The Scuderi Group will present two technical papers during the upcoming SAE World Congress (12-14 April 2011) in Detroit: 1) “Scuderi Split Cycle Research Engine: Overview, Architecture and Operation” and 2) “Scuderi Split Cycle Fast Acting Valvetrain: Architecture and Development”.
I wondered if anything good would ever come of the Scuderi engine. I've been following it for a while, but I thought they had scrapped the idea now that electrics and hybrids are becoming so popular.
The engine has so many new technologies going on, it's almost hard to know what to make of it. I hope all of their claims are realized, and manufacturers are able to make it reliable and affordable.
Posted by: phoenix1 | 17 January 2011 at 10:13 AM
I still don't see how the Scuderi engine (which I must applaud for being novel) could be more efficient than a turbocharged atkinson cycle engine which would have a similar specific power to the scuderi engine while retaining the benefits of overextension without needing a special crank shaft or special valving.
Also, I'm still skeptical as to:
1. How the combustion piston/cylinder will survive without intermitent exposure to fresh air (like a normal ICE).
2. How effective the valving is between the compression and combustion chambers at maintaining its seal.
Posted by: GreenPlease | 17 January 2011 at 11:01 AM
Greater efficiency is easy; it doesn't have to keep the combustion cylinder free of "hot spots" or pull air into a cylinder that just expelled hot exhaust. That gets rid of two major sources of entropy increase right there. The Scuderi could use ceramic coatings or inserts on the combustion-cylinder head and piston, further cutting heat loss (and cooling load) and increasing efficiency and turbocharger power in the bargain.
Where this thing really belongs is aircraft. Fuel efficiency is crucial when you have to lift it.
Posted by: Engineer-Poet | 17 January 2011 at 12:35 PM
How does the Scuderi engine compare with the engines we now have, regarding oxides of nitrogen and also, power in proportion to size and weight? And, cost of manufacture?
Posted by: Alex Kovnat | 17 January 2011 at 12:38 PM
Look at the diagrams in previous posts. There's nothing out of the ordinary in the bulk of the engine, just a different mechanical arrangement and gas flow. The things I haven't seen described well are the fuel injection and ignition systems, but I don't see how they could be too different from current practice in e.g. diesels.
Posted by: Engineer-Poet | 17 January 2011 at 12:54 PM
This engine may be 25% more efficient than the NOT so efficient engine used the Cavalier 2000-2004, but how does it compare with the more efficient engines used in the Sonata 2011?
Posted by: HarveyD | 17 January 2011 at 01:06 PM
Hopefully the over 20% improvement will prove practical.
This 300 page renewable energy book may interest some readers: http://2greenenergy.com/wp-content/uploads/2010/11/REFFeBook.pdf
Posted by: kelly | 17 January 2011 at 02:14 PM
"Key to Scuderi’s split-cycle design is that it fires after top dead center."
Back in my test cell, every time the ignition point is retarded, the exhaust temperature gets really high and the efficiency drops even when the ignition point is still far from the TDC. Now someone is telling us that by firing it after TDC, they get 25% efficiency improvement in the simulation?
Well, good thing is they claim that the engine will be in production in few years time, I cant wait to put into the dyno.
Posted by: Account Deleted | 17 January 2011 at 04:40 PM
azmio
they claim that because they create a massive turbulence then the combustion is ultra-fast and then delaying the ignition after the TDC doesn't affect the efficiency. The gain of efficiency is obtained through more complete combustion improve torque because you fired after TDC, also you can work more in a Atkison type of cycle because of the split cycle . But right 25% improvement is not necessarily better than new generation of Direct injection downsized turbocharged engines that are becoming mainstream fast. The Scudderi is more interesting for diesel engines because it reduces NOx emission.
Posted by: Treehugger | 17 January 2011 at 05:04 PM
Still waiting for test results of actual hardware. Don't believe this will amount to anything until they build and test prototypes and provide the test data proving their claims. Smells fishy; always has.
Posted by: Nick Lyons | 17 January 2011 at 10:07 PM
Testing has been done, and it seems to work.
Posted by: Engineer-Poet | 18 January 2011 at 06:18 AM
tree
combustion efficiency for a typical modern engine is already ranging between 95 to 99%. improving it any further will not simply increase engine efficiency. i am skeptic about people who claims to improve combustion efficiency that is already high and yet claiming to improve the engine efficiency by as much as 25%.
back to firing after tdc, have you tried firing an engine after tdc? many did and by the time the cylinder pressure builds up, the piston is already more than 20% away from the tdc. the cylinder volume is alrwdy increased that pressure increase ifrom gas expansion is minimal. now help me to understand on how possible it is to improve engine efficiency if the combustion heat is just wasted s exhaust heat
Posted by: Account Deleted | 18 January 2011 at 08:02 AM
azmio, I think I understand your misconception.
The "firing after TDC" in the Scuderi doesn't mean the same thing it does in a conventional engine. In the Scuderi the expansion cylinder hits TDC before the compression cylinder, so compression isn't even complete at "TDC". If fuel is injected as the air charge moves through the crossover passage, it can burn very quickly. You'll have to tell me how fast combustion could be complete, but I suspect that it might finish even earlier than conventional engines which rely on swirl or tumble for flame propagation.
Posted by: Engineer-Poet | 18 January 2011 at 08:27 AM
Hi all,
I've loved this site for a long time but I mostly skip the comments because of all the self appointed experts with nothing positive to say.
I think Scuderi might be on to something here with the split cycle, and the air pressure hybrid concept. Why not give them help, encouragement or investment, if not that then just give them a chance to succeed or fail with out prejudging the outcome. Because if you really knew the perfect solution to these problems, you would have built the hardware and proved it.
Posted by: CrazyCarLarry | 18 January 2011 at 08:36 AM
SAE listed the EcoMotors OPOC engine as one of the top technology stories of 2010. I wonder how the two engines compare as far as efficiency. This engine seems much closer to current technology, but Bill Gates and Vinod Khosla (Sun Micro) are putting money into OPOC.
http://www.tscombustion.com/SAE20101207AuotmotiveEngineering.pdf
Posted by: Glien | 18 January 2011 at 10:38 AM
@Engineer-Poet:
Yes, I know they have built a prototype and run it. However, I can't find any discussion of test results which validate any of their claims for increased efficiency--only endless 'studies'. I guess I'm channeling my mother, who was born in Missouri--show me.
@Niel Bob: OPOC looks very promising to me: mechanically simple, compact. I'm betting their claims for increased efficiency are overblown as well, however.
Posted by: Nick Lyons | 18 January 2011 at 10:58 AM
"The "firing after TDC" in the Scuderi doesn't mean the same thing it does in a conventional engine. In the Scuderi the expansion cylinder hits TDC before the compression cylinder, so compression isn't even complete at "TDC"."
misconception? i dont think so, your explanation above describes what's happening with the scuderi engine and that's where my concern is.
if the pressure wave hits the expansion piston after the piston has left the TDC, the effect is similar to firing the piston engine after TDC. I wish that I can make you see the test results that we have in igniting the charge after TDC.
oh, by the way, engine similar to scuderi has been available at the beginning of 20th century in england. Just google for dolphin engine.
Posted by: Account Deleted | 18 January 2011 at 05:02 PM
Larry,
what's wrong with using a forum like this to have a healthy debate. The points and concerns brought up can be highly advantageous to scuderi if someone can come up with a convincing answers. Unfortunately for us all, there is none up to now that can be used to support scuderi's claim.
There are many snake oil businesses around the world that make claims as if all others are plain idiots and no nothing about the subject. There is nothing wrong in proving that scuderi is not one of them.
Posted by: Account Deleted | 18 January 2011 at 05:08 PM
- Flame propagates through the cylinder later.
- The late burning leads to lower BMEP.
- The late-burning charge does less work through expansion and remains hotter, raising the EGT. (This is a tactic which has been used to accelerate catalyst light-off. Yes, I have done work related to emissions control.)
What you don't seem to realize is that having ignition before TDC is a compromise. The cylinder pressure starts rising while the crank is still doing work to compress the charge. Ideally ignition would be exactly at TDC and the charge would burn completely before the piston moved downward, but in a world of finite flame speeds, simple mechanical systems and low-octane fuels, this is a long way from reality.The Scuderi works around some of those issues. This is the twilight era of the internal combustion engine, but it will still be quite useful in the next few decades.
Posted by: Engineer-Poet | 18 January 2011 at 10:14 PM
poet
i dont see any more point in debating with you any further with regard to the late firing. As scuderi has been telling us that the serial production will be in few years time, every year since the last few years. I will test the engine in my test cell once it's out in the market. I am sure that we can revisit the topic above during that time.
Anyhow your point "The late-burning charge does less work through expansion and remains hotter, raising the EGT. (This is a tactic which has been used to accelerate catalyst light-off. Yes, I have done work related to emissions control.)" are you saying that late burning that is a norm for catalytic converter heating will also be done by scuderi at part load, medium load and full load? I raise this point because unlike that variable valve timing mechanism, scuderi crankshaft cant be varied to change expansion piston position relative to the compression piston position.
Your next point "What you don't seem to realize is that having ignition before TDC is a compromise. The cylinder pressure starts rising while the crank is still doing work to compress the charge". Well i realize it well that every engine speed and load has its own optimal ignition point. Firing it too early and the piston ends up compressing the expanding gas. Firing it too late will cause less conversion of combustion heat into useful kinetic energy of the piston. Of course there is an exception according to you and Scuderi, by firing it late, efficiency can be increased by 25 percent
"The Scuderi works around some of those issues. This is the twilight era of the internal combustion engine, but it will still be quite useful in the next few decades." There is nothing new about the scuderi engine, the british has been running split cycle with reasonable success in the early 20th century.
Posted by: Account Deleted | 19 January 2011 at 07:03 AM
I get the feeling you're married to your misconceptions. I was trying to get you an annulment, but I am at the point where I think I don't care any more.
I believe we'll see the Scuderi on the market in the next few years because it allows hybridization through compressed air rather than batteries or hydraulics and it's easily built in today's engine plants. One or the other of us will be able to say "I told you so".
Posted by: Engineer-Poet | 19 January 2011 at 05:42 PM
same thing i can say about you too. i do review engine and combustion related paper in journal, why not you write a paper about the scuderi engine and let all the reviewer comment on your points
Posted by: Account Deleted | 19 January 2011 at 06:45 PM
Why would I write the paper? I review papers when I find them (and they're open acess), same as you.
I have to wonder about your obstinacy, but maybe that's due to different experience. I've been around the labs which tested the all-ceramic adiabatic diesels (I've played with a silicon nitride piston and cylinder pair, lapped so close they sealed without piston rings). The scuttlebutt was that they didn't pick up a lot of efficiency directly, because the premature heating of the intake air charge from the hot combustion chamber delivered a big hit to entropy and also caused NOx issues; the gains came from turbocompounding. It's immediately obvious that the Scuderi scheme gets around the charge-heating issues. Also, uniflow engines have long been known to have higher efficiency due to lower heat-transfer losses. The Scuderi system is uniflow.
Scuderi has first principles and some test results. You have... skepticism, to the point where you say you won't trust anything until you measure it yourself. Why bother with the literature, then?
Why do I bother? Maybe this: http://xkcd.com/386/
Posted by: Engineer-Poet | 19 January 2011 at 09:28 PM
Ok, gentlemen, 25% gain in comparison to a 2004 Cavalier isn't much, as Harvey D stated, since the 2004 Cavalier is not the latest in ICE technology.
How about the Scuderi's vs. the latest in HCCI capable of extended load range operation, similar to the MB DiesOtto engine? Or how about Scuderi vs. H2-optimized-ICE capable of ~50% efficiency, due to the very fast and very lean burning capability of H2? How about Scuderi's vs. the result of dual-fuel (gasoline and diesel) combustion as shown by the work of the Lund University, capable of ~57% indicated efficiency, or the work of the University of Wisconsin, capable of over 50% efficiency?
Ultimately, in 2015, H2-FCV's will be mass-produced by leading auto MFG's. These FCV's will be capable of >70 mpg and having the emission problem completely solved, as well as the petroleum dependency.
Posted by: Roger Pham | 19 January 2011 at 09:33 PM
there is nothing wrong about being skeptic, the split cycle engines have been around and have been abandoned. the engine still needs a lot of cooling and it still emits lots of waste heat through the exhaust, to simply say that 25 percent is possible based on simulation is a bit too much.
the ceramic engine has been around for a long time too and us army has tested it and decided not to proceed with it.
to me if anyone is interested in gaining lots of efficiency, air as the cooling and expansion agent needs to be replaced with a better medium like water. if the engine still requires radiator and still emits lots of hot exhaust gas, large thermodynamic efficiency is just impossible and this applies to all sort of heat engines like gas turbine, piston engine and for sure the scuderi engine
Posted by: Account Deleted | 19 January 2011 at 09:43 PM