The Bourke Engine Solved Virtually All Imbalance Problems In 1930 With Only 2 Moving Parts! 20

[Cryptoman]

thread71-376751
Anyone seen the CMC Sytek Scotch Yoke Engine? Completely kills the imbalance problems that conventional direct couple conn rod types suffer from. Interesting how it resembles the Original reverse cam effect Bourke Engine invented by Russell Bourke back in the early 1930's!
But what about utilizing only half the scotch yoke and applying it to conventional inline 4 and 6 cylinder engines? I thought this up decades ago when I was first introduced by a friend to the Bourke Engine Documentary written by Lois Bourke back in the early 70's. Have wondered what the real world result would be for a very long time and due to lack of resources, have not yet been able to find out. Would be easy enough to simulate on today's super fact computers.
It is very easy to realize that this solves imbalance and piston side loading problems associated with conventonal conn rod setups due to lack of direct coupling of the conn' rod to the throw. This advantege is obvious to anyone who can see and think.
One of Russell's main goals was to cure all vibration problems inherrant in conventional engines.
Also, there is a free piston engine design called the Bourke Engine, invented by Russell Bourke back in the 1930's! Basically a dual 2 stroke cylinder design with pistons fixed to a ridged inline connecting rod through a scotch yoke mechanism that simply imparts power to the rotating mass as it is not directly coupled thereto. Sort of the mechanical version of passive agressive!
Russell Bourke designed the worlds first HCCI engine without realizing it or at least without naming it correctly. His primary discovery and goal was to achieve clean cool environmentally friendly exhaust emissions via an inverted combustion process known in conventional terms as pre-ignition! He so acheived these goals in his design. His purpose was to do away with multiple parasitic power robbing parts and that's exactly what he achieved way back in the 1930's! It's still the worlds most efficient piston I/C engine ever too!
For free info -

http://www.bourke-engine.com

/

http://www.projectbourke.com

 

[EHudson]

Mr. Kirk not only spent his own money to acquire the best replica of an original Bourke engine for testing, he subsequently built a four cylinder radial engine of his own design which incorporated a scotch yoke. He exhibited and ran his X-4, air-cooled engine at the EAA convention many years back. The engine produced respectable, (approximately 1 hp/cubic inch), power. As one of the few people who have designed and built a scotch yoke based I. C. engine, he has made considerable effort to explore the virtues of the mechanism. His comments on the scotch yoke are much more than speculation.

 

[SomptingGuy]

Unfortunately, the details of the air pump mechanism don't affect the Carnot efficiency limitations.

Steve

 

[BrianPetersen]

My German is not good, but I couldn't help but notice that the name Ficht appears in the youtube link that Cryptoman posted.

Ficht, if it is the same company (probably), developed a direct-fuel-injection system for two-stroke spark ignition engines, which was subsequently used by Outboard Marine (Evinrude) for some time. I believe this system has since been replaced by other technology, but it was around for a while. Obviously the intent with all such direct-injection systems on two-stroke engines is to address the fuel consumption and emission control shortcomings of traditional carbureted designs.

The OMC engines obviously used a traditional crankcase-scavenged bottom end, although with oil injected directly (as opposed to being premixed with fuel - necessary, since the fuel no longer passes through the crankcase).

https://www.youtube.com/watch?v=-QN-5uTZC7w

 

[Cryptoman]

Good morning friends!
Thank you for the validations Dave!

https://youtu.be/2-25aj82Nuc

https://youtu.be/2-25aj82Nuc?t=101

Scotch yoke engines don't work eh?
By the way, the Bourke engine was a MONO STROKE engine, not a 2 STROKE by way of the 1 piece connecting rod mechanism. PROOF of the 1 stroke cycle!
A Vaux 500 is not a Bourke Engine. It's a modified version of the original Bourke 30 where Melvin too lots of short cuts.
Also, Melvin Vaux came up with what he thought was an improved version of the original Bourke 30.
It utilized a square cup with a radius cut out of each rod shoe to increase dwell time at btc and tdc.. it also used a center drive gear as it's pto where a total of 4 cylinders were driving at HIGH RPM!
The engine ran on natural gas and other fuels and drove a genearator under load for quite a while.
Further, Melvin created a 350 cu 2 cylinder version (known as the Vaux 200) and ran an irrigation pump with it on natural gas for years. It has been on display in a museum in Shafter Ca for years now since Melvin's passing.
I personally witnessed the DeVaux 4 cylinder engine run and when it did, it made a horrible rattling noise which was clearly the outer surface of the 3 layer bearing rapping against the shoe face every time the opposing cylinder fired! = JUNK in my opinion.
The Vaux 200 did not rap because the shoe facings were flat.
Just because someone tried and failed to achieve the Bourke Cycle doesn't mean it's not achievable, it simply means the experimenter failed to prove conclusively one way or the other that the Bourke Cycle is a myth!
If one simply looks, reads, studies and duplicates Russel's work, one should be able to achieve the same results as Russell! There are video's of live Bourke engine runs that prove this FACT!
There are no video's or any real evidence of the experimenter's findings one way or the other and one cannot write TRUTH into existance, no matter how many pages! PERIOD!
Another thing the experimenter proves is that "one must throw away all they've learned about conventional engines and start completely over to understand the Bourke Cycle!"
This fact still frustrates and confuses conventional engineers to this day!
Fitch was obviously on the right track in proving Russel Bourke right! And so they did! Well done Fitch!
Article from HotRod Magazine 1954! Russell was making waves and history!

http://www.projectbourke.com/hotrod.htm

Enjoy!
Cryptoman

 

[BrianPetersen]

What is the P-V diagram of the "Bourke cycle"?

The page that you linked to indicated "At about 90 degrees before top dead center, ignition occurs as compression continues." I cut-and-pasted those from the linked article.

Really?

"Since all heat is extracted at the top of piston travel" ... Really? And ignition happened 90 degrees before top dead center? What happened to the combustion that occurred after ignition and before top dead center? What part of the cycle was it in when *that* happened?

 

[SwinnyGG]

By the way, the Bourke engine was a MONO STROKE engine, not a 2 STROKE by way of the 1 piece connecting rod mechanism. PROOF of the 1 stroke cycle!

I know I'm wasting my time here. But... no.

A '1-stroke engine' would be an engine where the piston moved from TDC to BDC and never returned.

 

[BrianPetersen]

By the same argument, the relatively conventional Fiat 1.4 in my daily driver is a one-stroke engine.

By the same argument, the relatively conventional Mopar 3.6 in my van is a two-thirds stroke engine.

 

[Tmoose]

According to the old Hot Rod article it seems likely it was not Mr Bourke who called it a "one stroke." As I read thru what Cryptoman has provided, David Wolfe, Founder, Bourke-Engine.Com, is the originator of the "one stroke" .

Unfortunate.

 

[RVAmeche]

I don't understand you Cryptoman. You have several anecdotes about various engines reportedly using "the Bourke Cycle" which you cite as evidence that it's feasible/reliable/superior. Yet you've said a few times that even you, an energetic supporter, are not sure if this cycle is real.

Dave Kirk acquired a replica engine and did actual testing. His article notes some of the design changes you mentioned and he has actual data, something that is conveniently missing from other claims of "replicating" the engine. You ask why he didn't record it on camera (an expensive proposition in 1980) to imply his tests weren't accurate, which is rich considering none of the supporters have as much documentation.

Bourke was just another snake oil salesman trying to earn money by making outlandish claims and the mythology and lack of testing to support his claims show that.

 

[RodRico]

I have a cure for cancer. I have no evidence supporting my claim, but many sites on the internet support my ideas. While those sites will help those with an open mind grasp my approach, be forewarned one must throw away all they've learned about medicine and start completely over to understand it. Pay no heed to the many critiques of my solution by so called "medical experts;" one cannot write TRUTH into existence, no matter how many pages! (Please ignore those who say I'm the one trying to write truth into existence).

 

[btrueblood]

Videos of running engines, but no videos of engines running with torque/power measurements, nor of fuel consumption. Pretty basic stuff, but no video, much less any other documentation.

Love the German videos. 5 minutes of black screen...? And again, no power measurements, no fuel consumption data, no data or documentation to speak of.

This pannetone is delicious.

 

[waross]

One stroke? Wankel? No stroke?
Just asking. I got lost trying to visualize a working one stroke.
Diesel hammer used for pile driving?
Diesel Hammer. One stroke?


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[gruntguru]

RodRico (Automotive)14 Jan 19 14:02
I have a cure for cancer. I have no evidence supporting my claim, but many sites on the internet support my ideas. While those sites will help those with an open mind grasp my approach, be forewarned one must throw away all they've learned about medicine and start completely over to understand it. Pay no heed to the many critiques of my solution by so called "medical experts;" one cannot write TRUTH into existence, no matter how many pages! (Please ignore those who say I'm the one trying to write truth into existence).

Hi Rod. Please link me to some of your web sites. I want to become a believer! I know that big pharma is suppressing your idea because it will ruin their business model. (They are too stupid to realise that if one of them breaks rank and markets your cure, they will dominate their opposition overnight)

Same goes for the Bourke engine of course. World beating technology suppressed by companies too stupid to realise they could make a fortune by getting in first and marketing it.

je suis charlie

 

[TugboatEng]

One stroke? Wankel? No stroke?
Just asking. I got lost trying to visualize a working one stroke.
Diesel hammer used for pile driving?
Diesel Hammer. One stroke?

Still a 2-stroke, a free piston 2 stroke engine. It's the same cycle as an opposed piston engine except the bottom piston doesn't move much.

 

[RVAmeche]

Reminds me of That 70s Show:

And they've got an air cooled fiberglass engine, man. It runs on WATER man.

 

[Dave Kirk]

Gentlemen –

Thank you to all that have welcomed me to this site…much appreciated.

I was disappointed in the outcome of the Bourke engine evaluation, especially after all the time, money and dedication that I expended. There was good that came of this though. The Sport Aviation article put me in touch with a number of people that had experience with Russell Bourke personally, some of whom constructed and tested their own Bourke engines, and one person who actually dyno tested an original Bourke “30”. I found it interesting that his test results were almost identical to mine – that is, 9 bhp @ 4000 rpm. In conversations with those that knew Bourke personally (Melvin Vaux), I learned that Bourke was hot-tempered, hard to work with, and greatly exaggerated his claims.

The feature that initially attracted me to the Bourke engine was the combining of the scotch yoke crank mechanism with the two-stroke operational cycle. In studying the patent literature, it was readily apparent that Bourke was NOT the inventor of this configuration – patents extend back to the early 1900’s describing this embodiment almost exactly. One of particular interest is U.S. Patent 981995, entitled “Motor”, January 1911. The drawings describe a 6-cylinder 2-stroke radial layout using 3 scotch yokes with crankpin yoke rollers used – uncannily resembling what Bourke patented 25 years later in 1938. One wonders if this document was originally viewed by Bourke and provided him “inspiration”?

The real attractiveness in this mechanical combination is that, due to the pure linear motion of the piston rods, the cylinder scavenge pumps (normally the crankcase of a conventional 2-stroke) can be totally isolated from the crankcase mechanism. This allows a full, circulatory lubrication system to be employed, thereby supplying undiluted oil to all of the highly loaded bearings. The pure harmonic motion of the rod-yoke reciprocating assemblies offers the potential of excellent engine balance if properly configured and counterweighted. All of these advantages are gained without complicating the basic simplicity of the 2-stroke engine. Preliminary layouts showed a very compact engine could be achieved especially with oversquare bore/stroke ratios.

Encouraged by a good friend who offered financial support, I decided to design an engine that would correct all the design faults uncovered in my prior Bourke engine testing. Due to my love of aviation and being a member of EAA, an aircraft engine application was most appealing. The ARV (Air Recreational Vehicle) market, then becoming very popular, required engines of 18 – 25 bhp and this defined the preliminary goals of the project. Initial layouts and basic calculations showed that by using 2 recip assemblies oriented at 90 degrees from each other, a compact 4-cylinder X-radial engine was possible and that 100% primary balance was achievable with proper crankshaft counterweighting. As 25 bhp was the target power at 5000 rpm (direct drive turning a 36” diameter propeller) a realistic bmep of 80 psi was selected for good reliability. These parameters sized the displacement at 25.2 cu in, or 6.3 cu in/cylinder.

Over the next 18 months, I performed all of the engineering calculations, design work, and board drawings (no CAD back then) all as a spare-time endeavor (I have a very understanding wife). All of the features found detrimental in the Bourke engine were corrected and these were as follows:
• Scavenge pump compression ratio was reduced to 1.4:1, a typical value for high performance 2-stroke engines. This was achieved by incorporation of an integral volume chamber between the cylinder and crankcase that added nothing to the weight or physical size of the engine.
• Cylinders were designed with Schnurle porting (loop scavenging) that utilized 2 main and 2 boost transfers, allowing non-deflector (slightly domed) pistons to be used. Conventional piston-controlled intake and exhaust ports were utilized.
• In the Bourke design, piston rods were supported and guided by bushings in the crankcase. The reaction forces (torque applied to engine frame) of the rod yoke assembly was absorbed by relatively small surface area bearings, contributing to high unit loads and heat transfer into the crankcase. In my redesign, pistons are rigidly attached to the piston rods with piston skirts carrying this reaction force. Only Teflon lip seals with radial compliance were used at the crankcase/scavenge pump juncture, sealing around the ground and polished piston rods.
• Knowledge of 2-stroke gas dynamics and attention to gas flow allowed non-restrictive passages and proper port time-area relationships to be incorporated. A 4-into-1 exhaust system was designed to utilize inter-cylinder tuning, allowing properly timed positive pressure wave to arrive prior to exhaust closure, contributing to good trapping efficiency.
• A gerotor oil pump supplied oil from an oil tank for direct spray lubrication of the rod yoke bearings. I did use the yoke roller design as lubrication requirements are greatly simplified versus a pressure lubricated slider block. Oil return back to the tank was via gravity. Cylinder lubrication was via cylinder located, drilled oil ports communicating with oil mist in the crankcase, with one-way check valves being used. Vacuum created in the scavenge pump drew oil mist onto the bore surface.

Patterns were made, castings completed, and machining for the first prototype were done by local machine shops and friends. With very little development work (mostly sorting out the lubrication system), the engine made it’s target performance goals. After a little tweaking, best power recorded was 27.5 bhp @ 5300 rpm. For power measurement, I constructed a torque stand whereby the engine was rotationally supported and balanced. Torque measurement was read from a 1-foot moment arm directly to a spring scale. I had a selection of 3 different-pitched propellers such that I could run 3 load points – sufficient for initial evaluation.

I displayed and ran the engine for 2 consecutive EAA Fly-In events in Oshkosh WI. It received lots of interest, however it was never produced due to the legal liability aspects involved with such a product. I put about 30 hours of WOT testing on the first prototype with no failures or surprises. It was very smooth in operation, with only very slight vibration induced by the force couple due to the axial offset of the reciprocating assemblies. Best bsfc recorded was .606 lbm/bhp-hr at 4800 rpm (cruise setting) and .673 lbm/bhp-hr at 5000 rpm WOT. While these figures are by no means exemplary, they are typical of carbureted 2-stroke engines employing exhaust tuning. Final specifications were as follows:

Bore – 2.313”
Stroke – 1.500”
Total Displacement – 25.2 cu in
Compression Ratio – 7.0:1
Overall Diameter – 16.25”
Length – 21” (with Vertex Magneto)
Weight, Complete – 60 lbm
Fuel – Auto or Avgas, 100 octane low-lead avgas preferred
Best Ignition Timing – 28 deg btdc
Bmep – 78.6 psi
Rated Power – 25.0 bhp @ 5000 rpm

I wrote and presented a technical paper on this engine at the 1985 SAE convention in Milwaukee WI. For those interested, it is still available from SAE:

https://www.sae.org/publications/technical-papers/content/851518/

The paper describes the design rationale and specific engineering details that are too lengthy to discuss here.
I must advise those that are proponents of the Bourke engine – my X-4 IS NOT A BOURKE ENGINE! It exhibits no magical combustion phenomena, no incredible fuel efficiency, no cool exhaust temperature, no reverse-toggle action, no cyclonic turbulation, etc. It is a 2-stroke, homogeneous-charged/scavenged engine that performs comparably to a conventional exhaust-tuned engine. Benefits gained by the configuration are in operational smoothness, small package size, and employment of a more-conventional 4-stroke lubrication system…that’s it!

The take-aways from this project were the personal satisfaction in designing my own engine that met all the performance targets without anyone micro-managing or “supervising”, no legal department to contend with, no sales-marketing-purchasing department, etc., that we as engineers face in the corporate environment. Most of all, it demonstrates that a scotch yoke 2-stroke engine is a perfectly workable concept. Scaled up and equipped with a direct-cylinder fuel injection system, it could be a very attractive aircraft powerplant for general aviation.

Pictures of the “short nose” version of my X-4 appear below. Engine shown with the Vertex mag and exhaust system removed.

 

[Dave Kirk]

Rear view.

 

[waross]

The scotch yoke is not the only method of obtaining linear con rod movement.
The Wärtsilä-Sulzer RTA96-C uses a cross head with a slider and a second con rod to the crank shaft.
They may be using the space below the piston to charge an adjacent cylinder rather than the same cylinder.
I can't find the details but this arrangement could possible be more efficient that feeding the same cylinder.
With suitable timing, the air may be transferred to the second cylinder with little increase in pressure, saving the heat losses associated with compressing the scavenge air.
Here's the link. For some reason that I can't put my finger on, I will wait for a second source of information before accepting all the details completely.
Wärtsilä-Sulzer RTA96-C

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[BigClive]

DK - your 4-cylinder engine is a very neat and compact design - surely it would have commercial applications and value?

 

[RodRico]

Kirk,

Very interesting. I'd like to see your engine posted as a separate thread rather than under this silly Bourke thread.

I've designed a new engine that also targets light aviation. Mine is a cam driven opposed-piston two-stroke HCCI six cylinder radial (rotating cylinder) with an integral piston driven air pump for every pair of opposed pistons. In this engine, piston side loads resulting from interaction with the cams is absorbed by sliding bearings in the rotor, so it will have some the same issues as a Scotch Yoke design. It's a high risk endeavor in my opinion, but still worthy of pursuing. I'm just now beginning fabrication of the prototype which, if successful, will hopefully draw interest from an established manufacturer. Per my analysis, the 12.38cc (2.06cc per cylinder) prototype in which each cylinder completes four full cycles per revolution should produce BMEP of 8.24 bar, 2.4 HP, and 4.8 lb-ft torque at 2626 RPM with 52.8% brake efficiency (63.2% thermal) and BSFC of 0.262 lb/hr/hp in 120.8 cubic inch volume. I'd be interested in hearing your observations some day if you're interested.

Great work on that engine you show! It really deserves it's own thread.

Rod