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Hit & Miss Gas Engine Discussion Meet collectors of hit and miss engines, ask questions about collecting, restoring and showing antique flywheel engines.

Hit & Miss Gas Engine Discussion

Brayton Cycle Engines


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  #41  
Old 02-08-2013, 11:06:21 AM
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Default Re: Brayton cycle engines

Hi, The flywheel on the red engine is right for that engine. Awhile back I was lucky enough to stumble onto pictures & information of that engine from 1915. It has a neat history but too bad the information has been misplaced with it over the years. The Smithsonian date on it is not right; also when researching Brayton, be careful not to believe everything you read, a lot of it is misleading. Pay attention to your sources & try to stick to original dated documents as much as you can.

Wayne T., I’ve never came across a picture of the backside of that engine you were asking about but I’m guessing like you guys said there was a simple eccentric to drive the exhaust valve, or 1 to 1 gears with linkage, & no governor. Not counting his experimental engines, I’ve found 2 production engines before that beam engine design (& there may be more before it waiting to be found). There are more Brayton cycles out there than people realize. Look forward to seeing your model, (at least a picture of its cylinder cutaway exists to work with).

-Nick
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  #42  
Old 02-09-2013, 01:11:35 AM
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Default Re: Brayton cycle engines

Nick,
Thanks for the info... I like your engines too.. the combo hit and miss throttler is the best IMO... Do you have plans to make a historical Brayton cycle model?
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  #43  
Old 02-09-2013, 08:37:49 AM
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Default Re: Brayton cycle engines

Here is a link to scuderi... they claim to have a patent on a split cycle engine... Their latest proposal is to create a hybrid by storing compressed air durring breaking.... then release the air during acceleration.

http://blog.autoshopper.com/articles...Good-Too-Late/

http://www.youtube.com/watch?v=x4jL-ACaV44

http://www.youtube.com/watch?v=QgSU3oHeByU

http://www.youtube.com/watch?v=ImLDSmQsQHs

---------- Post added at 07:37 AM ---------- Previous post was at 07:24 AM ----------

http://www.youtube.com/watch?v=B5W73rEF8pk
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  #44  
Old 02-10-2013, 09:39:49 AM
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Default Re: Brayton cycle engines

Copied from this site : http://usscubera.org/images/hist/ussholland1.jpg
The Holland VI or "Adder" used the recently patented Brayton petrol-fueled (gasoline) internal combustion engine and had one torpedo tube forward. Many of the USS Holland's features carried forward into contemporary WW-I boats: Engine/generator powerplants, battery/motor submerged operation, diving planes, and torpedo armament. Barely buoyant, USS Holland and subsequent Adder-class boats used mainly dynamic pressure on planes to submerge.

There is a lot of misinformation out there...Maybe Paul can clairify of this is true?

---------- Post added at 08:05 AM ---------- Previous post was at 08:02 AM ----------

And before the Fenian Ram... Thus, John Holland’s first submersible, subsequently known as Holland Boat No. I, was laid down in some secrecy at the Albany Iron Works in New York City. In the spring of 1878, the boat was moved to a second iron works in Paterson – more convenient for its inventor – and launched into the Passaic River there on 22 May. Holland I was 14 feet long, weighed 2-1/4 tons, and was intended to be powered by a 4-horsepower Brayton-cycle petroleum engine driving a single screw. Fitted with both ballast and compressed air tanks fore and aft, the boat had a crew of one – Holland himself. After some initial difficulty in trimming the craft – and failing entirely to get the Brayton-cycle engine to run on gasoline – Holland eventually connected the engine to a flexible hose from an accompanying launch and drove the boat with an external steam supply. For his Fenian backers, he succeeded on 6 June in demonstrating a surface run at approximately 3-1/2 knots, submergence, an underwater transit at a depth of 12 feet, and a return to the surface. In a second trial, Holland kept his boat on the bottom for an hour and returned safely, which so impressed the Fenians that they agreed to fund a larger version. Having satisfied himself of the need to ensure stability with a reserve of positive buoyancy and a fixed center of gravity, the relative inefficiency of amidships hydroplanes, and the eventual perfectibility of the petroleum engine, John Holland stripped the boat of usable equipment and scuttled it in the Passaic River.

Is this information accurate?

Copied from this site : http://www.navy.mil/navydata/cno/n87...9/holland2.htm

---------- Post added at 08:08 AM ---------- Previous post was at 08:05 AM ----------

more from the site above:
” The Ram’s spindle-shaped hull was 31 feet long and roughly six feet in diameter, with a shallow conning turret on top. Powered by a two-cylinder, 17-horsepower Brayton-cycle engine and armed with a co-axial pneumatic “dynamite gun”2 in the bow, the 19-ton boat was intended to support a crew of three: a commander, an engineer, and a gunner.

---------- Post added at 08:39 AM ---------- Previous post was at 08:08 AM ----------

A Quote from Paul Grey:

The Brayton cycle is combustion at constant pressure. The Brayton engine orginally stored a compressed fuel/air charge in a receiver and admitted it to the cylinder under pressure while burning as the piston advanced to ~40% of the stroke. A "gauze flame interrupter" kept the flame in the cylinder from flashing into the receiver and popping off the safety valve (scary) . Apparently, once it was lit off, the combustion repeated with out ignition. Some engines has a bit of platinum sponge near the admission port to keep the mix lit. Later Brayton marine engines used compressed air and injected petrol into the combustion chamber through the intake port with a wick in it. Pumping losses never made the engine as efficient as Otto's cycle. A jet engine does the same thing, but pushes against a turbine instead of a piston. Good discussion in Lyle Cummins book, Internal Fire.


I didn't know about the platinum or the use of a wick... thanks Paul
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  #45  
Old 02-10-2013, 12:21:59 PM
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Default Re: Brayton cycle engines

Here is one of the last of brayton's patents 432,260. Page 3 line 80 describes the platinum ignition device. Note the air valve at the piston bottom and what appears to be a double acting rocker arm. With all the free space above the piston at TDC, it probably hurt efficiency. Perhaps in operation it was more like a combination of a Brayton and oil engine??? I'll have to read it more closely.
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  #46  
Old 02-10-2013, 11:27:48 PM
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Default Re: Brayton cycle engines

Thanks Paul, That's interesting.. Guna have to study that for a while... Sorry I misspelled your name on the post above.. Paul Gray not Grey...

---------- Post added at 10:27 PM ---------- Previous post was at 09:44 PM ----------

Paul, I think this is a 2 stroke engine with pilot ignition. I think the back side of the piston is an air pump, The exhaust valve is at the top the fuel travels through the center of the exhaust valve. injector goes through the center of the exhaust valve. The rocker operates both the exhaust valve (pushing) and the fuel injector (lifting) . The reservoir on the side of the cylinder contains fuel and the vapor goes through the tube into the cylinder to provide the pilot for ignition. This is my guess...
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  #47  
Old 02-11-2013, 12:36:53 AM
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Default Re: Brayton cycle engines

A couple more thoughts... the chamber on the left side of the cylinder is for starting... A smoldering rag or something to hold the flame inserted here... I think the piston pushes on the rod that's in the center of the exhaust valve to spray the fuel.
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  #48  
Old 02-11-2013, 02:46:03 AM
Bill Schaller Bill Schaller is offline
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Default Re: Brayton cycle engines

I don't know if you guys have seen these.

http://books.google.com/books?id=EPI...page&q&f=false


http://books.google.com/books?id=Hhv...page&q&f=false
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  #49  
Old 02-11-2013, 05:40:45 AM
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Default Re: Brayton cycle engines

Very nice Bill thank you!
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  #50  
Old 02-12-2013, 12:18:32 AM
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Default Re: Brayton cycle engines

After another review I've notice this engine does indeed have a small air reservoir which makes it a pure brayton cycle engine in every way.

I'll post the video again so it doesn't get lost in the mix...

http://www.youtube.com/watch?v=QgSU3oHeByU

---------- Post added at 11:18 PM ---------- Previous post was at 11:13 PM ----------

Mr. Ridders has made models of manay differnt types of engines... they can be viewed here...

http://ridders.nu/Webpaginas/pagina_...t_frameset.htm
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  #51  
Old 02-12-2013, 06:12:53 AM
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Default Re: Brayton cycle engines

Even though he has labeled it a Scuderi engine what Mr. Ridders has made is clearly and by every definition a Brayton cycle engine. I don't believe he was even aware the Brayton engine existed when he made his model. Here is a link to his excellent description of working with the cycle.

http://heetgasmodelbouw.ridders.nu/W...i_frameset.htm
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  #52  
Old 02-12-2013, 10:38:00 PM
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  #53  
Old 02-13-2013, 10:26:39 PM
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Default Re: Brayton cycle engines

Quote:
Do you have plans to make a historical Brayton cycle model?
I’ve definitely thought about it; I have the 4-stroke Brayton cycle engine Paul posted a patent pic of on CAD. The problem is time & right now there’s other stuff to take care. It’d be neat to see replicas of his engines but to do this would be huge undertaking. See John Burns’ amazing effort on a full-scale Reid engine at http://www.smokstak.com/forum/showthread.php?t=37903
After doing my last patterns I found a way of making large or small stuff cheaply & quickly; although casting cost & machining time would be the same.

Wayne T,
Some basic dimensions of the engine in the picture you were asking about is that it was “32 inches base & 5-1/2 feet tall” & that it was “simple with few parts”. Company literature from 1872 says production engines ran on “the vapor of carbon oils” or “off the nearest gas burner” & could be adjusted to run at 60 to 500 rpm. I have indicator card diagrams on a tested engine that show how it was timed. The cut-off could be “manually” adjusted (no governor). Some tests show the cut-off at about ¼ stroke, others at ½ & 3/4. In 1873 there was a test of one of these 5hp engines in New York City by Prof. Thurston. This is the same engine that was “expected to be at the Vienna International Exhibition but failed to show up in time to be judged.” (It’s one like shown in the 1st picture below) While it’s usually not thought that high compression was tried until later, this engine design & some other Brayton engines built before it were tested running with 100 lbs compression. (This is at a time when other people were using non-compression cycles). Later, in 1874 one of his engines was tested running with 150 lbs of compression.

This is a link to a neat article written later by a man remembering back as a kid while working around Brayton in the early 1870’s; it gives a good glimpse into Brayton’s life at that time.

http://books.google.com/books?id=az4...stands&f=false

The article tells about Brayton first playing around with metered-fuel injecting/carbureting on an experimental (2-1/2hp) beam engine of the 1872/1873 pattern design. I’d like to see a pic of the large 20hp “twin cylinder horizontal, naptha vaporizered” engine mentioned in the article; it was probably the predecessor of the double-acting, oil injecting engines built in 1876. (See the 2nd picture below) I haven’t seen them so have no clue which engine, but there’s a man that supposedly has original blue prints for a Brayton engine. Things got busy & I never followed up on it.


Final years of Brayton;

One of the most over-looked patents is Braytons patent 432,114 of 1890 (application filed in 1887). This was his idea for a 4-stroke cycle engine that used 2 to 1 gearing & fired every other revolution where it compressed pure-air on the compression stroke & then injected fuel into it by a “quick-acting” mechanical pump. In this patent he states things like “I have discovered that heavy oils can be mechanically converted into a finely-divided condition within a firing portion of the cylinder, or in a communicating firing chamber.” Another part reads “I have for the first time, so far as my knowledge extends, regulated speed by variably controlling the direct discharge of liquid fuel into the combustion chamber or cylinder into a finely-divided condition highly favorable to immediate combustion.” Ignition was initiated by a hot-spot & started when fuel was injected into the air after the compression stroke.

This engine was set up to exhaust a puff of air out at the beginning of the compression stroke. The effect would be the same as today’s miller or Atkinson engines seen in cars, & the Charon engine mentioned in another thread. Brayton does state in this patent that “the efficiency of the engine may be increased, however, by a higher rate (pressure) of compression, desirable in some cases.” These would have been efficient & extremely smooth-running engines.

Brayton went even further with this engine in that it was built with a backside condenser. Even though this plays no part in the actual engine cycle & makes the engine more mechanically complex, the engine could be run to extract more power from the burnt fuel. He states in this patent that the engine could be run on any fuel & that a 7” x 10” cylinder engine was built to the drawings & that it was run at 200 rpm & belted to a 30” fan rotating 1500 rpm for 10 hours & used 3-1/2 gallons of kerosene. It’d be interesting to see some actual tests.

Maybe due to difficulties with machining tolerances on his direct injection engine, his next patent (432,260 granted in 1890) is for a 4-stroke cycle engine using air-blast fuel injection. This is the one shown in the patent Paul posted above. (see the 3rd picture below) Clerk mentions testing one of these later engines & that “it shows a great superiority over the earlier type”. Does any one have a copy of these test results?

Brayton sent one of his 4-stroke cycle, air blast injection engines over seas to be judged at the 1892 Warwick show, it appeared in the show catalog but failed to show up in time. (this was the 2nd time this had happened). The big competitor at this show was Preistman, who I think won. Brayton’s engine missed the expo but was shown & demonstrated in the area afterwards. I’m not sure what happened to it. Later, in October Brayton took a trip to England. This was his first time over there & he planned to be back home for Christmas. He died while over there. “Some English friend” wrote back that it was from “enteric fever & neurosis of the heart”. Clerk wrote that he “died in Leeds while engaged in experiments on a new oil engine at a large works there”. This would probably resemble the engine shown in the patent (No 6138) Wayne T posted a pic of.

Some references mention that Brayton or his parents were English & settled in America but a man I’ve talked with over the years complied information on Braytons family tree & said “Francis Brayton who came to America sometime in the 1600's, down to the present Braytons are one heck of a family who have benefited humankind, and this country, over and over again. Doctors, teachers, lawyers, business people, public servants, the list goes on. We should honor them all and be grateful that Brayton #1 chose to settle in this land; I think we have all benefited mightily as a result.” He said most of George Brayton’s relation (sons, ect.) died from diseases & that “Brayton & his family (wife, ect.) are buried in Providence, RI cemetery in an unmarked grave.” Braytons’ companies seem to disappear shortly after his death.

Other brief notes on Brayton & his engines;

Early in the 1850’s he experimented with engines. These were engines using cylinders to which coal gas or camphene was introduced under pressure. In the late 1850’s his engines evolved enough that he built a production run of 5 engines of the same design. (These were some of the first production engines) They had a charging cylinder & fired the charge under pressure at constant volume while introducing it into a free-piston cylinder. I have an outline of these engines but am not sure how the free-piston’s rack & catch looked. It was probably something like what Barsanti & Matteucci used. It was while building these engines that Brayton found he could slow the violent explosion of gasses down by a screen.

In the 1860’s he mostly messed around with steam engines, boilers & improving machines & technology. He did build a couple experimental gas engines & had a nice running one to show in 1870. Although it’s not his cycle (see Cayley’s hot-air engine of 1807), this engine ran on the cycle Brayton’s most remembered for.

In October & November of 1871 the Exeter Machine Works was building Brayton engines. (These were probably the small 1/2hp engines like shown in his patent) Through the 1870’s & into the 1880’s he developed all kinds of configurations of continuous combustion engines & was involved with all kinds of side projects. (Cars, submarines, ect). The red engine at the Smithsonian is the experimental (pre-production) engine of that pattern style & used his new oil injection system. It was built in March/June of 1874. There are slight differences in it than later ones. Professor Blake (Eli Whitney Blake (1836-1895), professor of physics at Brown & of Telephone receiver fame) bought this engine not long after, (when Brayton was done getting the bugs out of it; something on the governor & cut-off). Blake used it with some of his experiments & later it ended up at Brown University & was used for driving an arc-light dynamo. It was donated to the Smithsonian in November 1951. The under-head beam engines (that are mostly seen in pictures & museums) appeared in 1875. The early ones had plain tube air chambers & later ones had extra support fins around the tubes (like on the Ford engine). A slightly different version of this engine had an oval base with the charge tanks inside. Before the 1876 Cenntennial, Brayton built a large double-acting beam engine that’s been shown a couple times in this thread. This was “probably the most highly finished engine he ever built”. I have a high resolution pic of this engine & you can zoom right into the nameplate & stampings on the engine. Test data & graphs also exist for it. I remember reading somewhere that Brayton was apprenticed years earlier by George Corliss & this could be part of what influenced Brayton to use so many beam designs on his engines; (& it’s neat they both had big beam engines at the Centennial). Brayton was also using air starts on some of his engines at this time. He was constantly changing the style of his engines but seemed to keep offering previous patterns of his engines for awhile, but with improvements. The 4th picture below shows an “over-head” beam engine that he was offering around 1880 along with other models. I love how he showed off the governor on this engine.

It’s said that Brayton acted as a stimulus to other inventors. One source says that while at the Centennial “Otto appears to have been much interested in the Brayton engine, as it was evidently very much in advance of his own.” I’m curious what month Otto was there?


Sorry for the long post but information is scattered on Brayton & I’ve just never seen a decent run-down of his life. I’m not the best writer so please bear with it. I’m sure there’s some errors & there’s a lot to add. I got interested in Brayton engines after seeing one as a kid; they stuck out from everyone else’s work.



Quote:
---------- Post added at 08:31 AM ---------- Previous post was at 08:11 AM ----------

you may like this.... http://www.youtube.com/watch?v=xn_nL1sQuuo

---------- Post added at 08:45 AM ---------- Previous post was at 08:31 AM ----------

I posted a you tube link to what is supposed to be a brayton engine but after watching the video im not convinced... I believe the video claiming to be a brayton is really a 2 cylinder loop scavenged diesel.. I thing it has a pressurized fuel tank and the rocker is running the injectors.. there are 2 glow plugs on each cylinder. I think at first he closes the compression release then closes the knife switch to start the glow plugs then opens the valve and fuel begins to flow which then starts the mosquito abatement program...
I’m sure about everyone would agree with that; but that engine was restored using the Brayton 4-stroke cycle patents as a guide & is why his name is mentioned. It’s a 2-stroke version of his 4-stroke engine. With decent air pressure & the fuel cranked up it’ll run in mosquito abatement mode like in the video. I don’t have the videos uploaded but with the air & fuel adjusted low & set right, it’ll run almost silent. (It’d be neat to see combustion diagrams of it).

It was a little hard to see but I enjoyed seeing the video of your engine running, it looked impressive with the glowing-red head!

-Nick
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  #54  
Old 02-14-2013, 06:15:48 AM
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Default Re: Brayton cycle engines

Nick this is great information... It sounds as though Brayton was onto a form of the diesel concept before diesel... thanks for clearing the air abt what's going on with the mosquito abatement engine... Who knows... if he had not died in England maybe we would be filling our tanks with Brayton fuel...?

---------- Post added at 05:05 AM ---------- Previous post was at 04:56 AM ----------

After some initial difficulty in trimming the craft – and failing entirely to get the Brayton-cycle engine to run on gasoline – Holland eventually connected the engine to a flexible hose from an accompanying launch and drove the boat with an external steam supply. For his Fenian backers, he succeeded on 6 June in demonstrating a surface run at approximately 3-1/2 knots, submergence, an underwater transit at a depth of 12 feet, and a return to the surface.

The expander side of the brayton would make a fine steam engine... It sounds like this is what happened... He used surface supplied steam to run the engine....

---------- Post added at 05:15 AM ---------- Previous post was at 05:05 AM ----------

If George Brayton would have known about the Chinese fire stick who knows what would have happened?
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Old 02-15-2013, 06:50:17 PM
Wayne Timms Wayne Timms is offline
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Default Re: Brayton cycle engines

Hi,

Nick, thankyou for the informative post. I had a rough estimate on the engine being 5ft tall. It looks like you have more information on this engine than I have and I would be interested in anything you have. The last photo you posted of a Brayton engine is a model I have not seen before. Do you have anymore information you can share on this picture and the engine, I may be persuaded to change my build plans.

I have posted a photo below of a Simon from Clerk, 1899. It looks to be the same engine that Wayne G posted in post 10.

Regards,
Wayne

www.bluefuel-whitesmoke.com
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Old 02-17-2013, 05:01:11 AM
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Default Re: Brayton cycle engines

Quote:
Originally Posted by nar View Post

Sorry for the long post but information is scattered on Brayton & I’ve just never seen a decent run-down of his life. I’m not the best writer so please bear with it. I’m sure there’s some errors & there’s a lot to add. I got interested in Brayton engines after seeing one as a kid; they stuck out from everyone else’s work.





I’m sure about everyone would agree with that; but that engine was restored using the Brayton 4-stroke cycle patents as a guide & is why his name is mentioned. It’s a 2-stroke version of his 4-stroke engine. With decent air pressure & the fuel cranked up it’ll run in mosquito abatement mode like in the video. I don’t have the videos uploaded but with the air & fuel adjusted low & set right, it’ll run almost silent. (It’d be neat to see combustion diagrams of it).

It was a little hard to see but I enjoyed seeing the video of your engine running, it looked impressive with the glowing-red head!

-Nick
Nick and others...
About 10 years ago I got fascinated by the thought of a compressor / expander piston engine. Kind of like a piston version of a gas turbine.. It seemed like such an easy thing to make. My first attempts at making a running engine of this type was to make a simple burner and add heat between the compressor and expander. For this kind of engine to run the expander volume has to be greater than the compressor. 2:1 is a good place to start. I can tell you it's not as easy as it seems to make a running engine of this type. I studied some early engines like the Bucket and Roper shown in the Cummins book.
If you can get one to run it is an accomplishment. But they are low power and efficiency and defiantly not the same class as a good running Brayton engine. .

When I made my little engine I extended the piston to preserve heat in the expander. Allowing it to run hot.. has other advantages too like super complete combustion and fuel mixture isn't even an issue... when the cylinder is hot fuel will burn as long as oxygen is present. Playing with that engine I learned a lot.. It was a test engine that could vary the stroke and crank positions of the expander / compressor.
I learned that adding heat prior to the expander is a bad idea that creates a lot of work for the compressor. Piston Brayton cycle engines are often described as constant pressure but in my mind they are really a split cycle engine. The early Brayton engines used a 1:1 expander / compressor ratio. If the pressure is constant the engine will never run.. The pressure has to be higher in the expander... Later I learned it was best to add fuel after the expander inlet valve closes. When this is done a lot of the back pressure on the compressor is eliminated. The engine is a lot more efficient and makes a lot more power. All of the drawings I've seen so far show fuel being added prior to the inlet valve but my guess is some portion of combustion had to be taking place in the expander cylinder. Is anyone aware of an engine showing the fuel being added after the expander inlet valve?

---------- Post added at 03:41 AM ---------- Previous post was at 03:08 AM ----------

It's unfortunate that Brayton never did really optimize his original engine design. I think he got close but it seems like he gave up and switched to compressing and expanding in a single cylinder. IMO the missing link is the timing of when fuel is added. A Brayton that begins combustion after the pressurized air is added to the expander behaves vary much like any other engine. Efficiency can be higher because compression is done in a cool cylinder while expansion takes place in a hot cylinder.

---------- Post added at 04:01 AM ---------- Previous post was at 03:41 AM ----------

Here is the Selden version...



One of my earlier attempts..




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  #57  
Old 02-17-2013, 12:18:27 PM
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Default Re: Brayton cycle engines

I've made a few of these turboturbines... I know it's called the Brayton cycle but the piston Brayton is not so easy... you can't just add heat between a compressor and expander to make it go.. It really is a different animal..



---------- Post added at 10:03 AM ---------- Previous post was at 10:00 AM ----------

http://www.youtube.com/watch?v=P-JDkedRRio



---------- Post added at 10:10 AM ---------- Previous post was at 10:03 AM ----------

Here is some cylinder details.. this is from Peter / our moderator...

---------- Post added at 10:50 AM ---------- Previous post was at 10:10 AM ----------



I think this picture was posted earlier in the thread but I posted it again because I think it's significant... I'm not sure whether fuel is being added prior to or after the expander inlet valve? It would appear the the tube labeled F is for the pilot flame? It's possible that the fuel enters just after the inlet valve but prior to the grating.. I think this grating was used to mix the fuel and air. Not like the earlier version that used a screen to prevent the flame from traveling back to the reservoir.

Here's a link to the other thread...

http://www.smokstak.com/forum/showthread.php?t=31002

---------- Post added at 11:16 AM ---------- Previous post was at 10:50 AM ----------

Paul Gray posted this picture of the mixing details of the Richards engine.

Interesting to compare the different designs.. I believe most all the engines added fuel as the air entered the expander.. If they would have added the fuel into the expander after the inlet valve closed the result is different.

---------- Post added at 11:18 AM ---------- Previous post was at 11:16 AM ----------



http://www.smokstak.com/forum/showth...=115633&page=2
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  #58  
Old 02-19-2013, 09:25:16 AM
imotorhead64
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Default Re: Brayton cycle engines

Even though Brayton gets credit for the cycle associated with the gas turbine I thought we should mention Barber who in 1791 proposed an engine with an air pump a burner and an expander turbine. Unlike the Brayton engine combustion was constant in the Barber engine. Supposedly a working engine was constructed and displayed at the Hanover Fair in 1972



later versions of this kind of engine were the Roper





There was also the Trewella engine.. A working engine was reconstructed by Mr. Bergy.. Here is the link.

http://www.stirlingsouth.com/Roy/ita..._recovered.htm

---------- Post added at 08:25 AM ---------- Previous post was at 08:18 AM ----------

Here's a link to the Wiki page on Barber.

http://en.wikipedia.org/wiki/John_Barber_(engineer)
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  #59  
Old 02-19-2013, 09:56:14 AM
imotorhead64
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Default Re: Brayton cycle engines

We should mention the Buckett and Cayley engines

These are the true constant pressure engines... They all have a compressor about 1/2 the size of the expander.

We should also mention the Ericsson engine.... similar to the Barber / Cayley style but heat was applied to the expander though is was external. Ericsson also used a regenerator like a Stirling.



I believe the Brayton is in a group by itself... combustion was not constant in a Brayton... and as I mentioned before the pressure in the expander must have been higher than the compressor otherwise the 1:1 ratio engine would not have run.

---------- Post added at 08:49 AM ---------- Previous post was at 08:40 AM ----------

I see of that version of the Ericsson the heat was applied between the recouperator and the expansion cylinder. Here is a version of the Ericsson that is very much like the Brayton except heat is applied externally.



---------- Post added at 08:56 AM ---------- Previous post was at 08:49 AM ----------

In this version of the Ericsson heat is applied to the expansion cylinder and the ratio appears to be 1:1

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  #60  
Old 02-20-2013, 04:10:27 AM
imotorhead64
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Default Re: Brayton cycle engines

I've been mentioning that I think the constant pressure engines and Brayton are not really the same... The difference is the Brayton adds fuel as the air enters the expander.. We know that Braytons all used some form of cut off... It's my opinion that because the atomization was like not very complete the fuel burned slowly and heat was still being added after the admission valve was closed. I thought a lot about the similarities between this kind of event and what happens in a Lenoir engine. Here is the Lenoir cycle copied from a post by Wayne Grenning.



Imagine this cycle engine connected to a compressor and an air tank... When the inlet valve opens and the piston starts to move down the stroke air rushes in and fills the void. There is more O2 for fuel burning and the air is more dense because it is compressed. Heating dense air produces a more dramatic result and part of that result is used to drive the compressor. IMO this is what happening to a degree in a Brayton piston engine.



The earlier the admission valve is closed the more expansion and more efficiency can be realized. I think this is what the Scuderi folks realized. In fact they often refer to their engine as a supercharged Lenoir cycle engine. They dont start combustion until the admission valve closes. Also another consideration is pressure added between TDC and a crank angle of abt 30 degrees isn't doing much work. Scuderi still adds fuel as the air passes into the expander. I think a better system is to have a very hot expander and dont add fuel or start combustion until after the admission valve closes... I'm not sure if Brayton ever tried delaying the fuel timing but I did it to a degree and I can say it seems to have a lot of promise.

---------- Post added at 03:10 AM ---------- Previous post was at 02:41 AM ----------

haha sorry wrong link...



Is there a revival of the Lenoir cycle on the horizon? Maybe if it's combined with a true Brayton cycle and a little bit of Ericsson's ideas of a hot expander...


http://lullencycle.com/

I believe the modern Brayton may look something like this...

[IMG]http://www.freepatentsonline.com/6601549-0-
large.jpg[/IMG]
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