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

 

[SwinnyGG]

Please correct me of I am wrong

Well... knowledgeable people in this thread are trying to explain why you're wrong, and you aren't listening.

 

[BrianPetersen]

Found an interesting article describing a real-world independent test.

http://acversailles.free.fr/documen...nce_testing_a_30_cubic_inch_bourke_engine.pdf

I'm not surprised by its findings.

"Too long, didn't read"?

Underwhelming, and did not live up to its claims - not even remotely close to doing so, when constructed as per original specifications.

 

[enginesrus]

It is still too expensive to manufacture, and the wear rates will be high depending on materials chosen.

 

[GregLocock]

Oh noes, we'd better end this thread or the cartels will send their black helicopters to eliminate every trace of this sekrit invention.

Continuing Brian's balance theme, an 8 cylinder Bourke engine would be fine for primary balance, with no balancer shaft required.



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[Dave Kirk]

During the 1980’s, this writer conducted a test of a 30 cubic inch Vaux engine, (a replica of the 30 cubic inch Bourke design), actually constructed using much of the original Bourke tooling. The goal of the test was to attempt to reproduce Bourke’s rather remarkable claims of 76 BHP at 10,000 rpm with stated brake specific fuel consumption values around .25 lbm/ bhp-hr. The project was undertaken with an optimistic approach to verifying the performance figures and to understand the thermodynamic processes that would allow these high specific power outputs to be obtained with high thermal efficiency.

The engine was tested on a water brake dynamometer after careful preparation and thorough break in. The test results were very disappointing, with power outputs and fuel consumption measurements being nowhere near what Bourke originally claimed. After many hours of careful adjustments and repeated tests, the best power recorded was 8.9 BHP at 4000 rpm where specific fuel consumption was a horrific 1.48 lbm/bhp-hr! The unloaded (free) speed was 5000 rpm maximum, a far cry from the stated figures. An induction airflow measurement revealed that the engine’s delivery ratio (volumetric efficiency) was only slightly better than 40% at 4000 rpm, dropping off sharply at higher engine speeds. It was obvious that this engine’s air handling characteristics were very deficient. My findings were as follows:

1) There was no indication of any unusual combustion phenomena occurring. Various low octane fuels were run and spark timing was advanced and mixture leaned in order to induce the “Bourke Cycle”. The engine responded like any other two-stroke – there was audible detonation with no increase in power output.
2) Best spark timing was around 35 degrees BTDC…any further advancing reduced power output. Leaning the mixture (via an adjustable main jet carburetor) past MBT (mean best torque) resulted in reduced power output. Using a 50:50 mixture of 87 octane unleaded gasoline and diesel fuel did increase the detonation intensity with no increase in power output or improved fuel consumption. The engine actually performed best on high octane gasoline.
3) The cool exhaust gasses were determined to be caused by fuel mixture short-circuiting out the exhaust ports during the scavenging process. The scotch yoke configuration allows the scavenge pump compression ratio to be very high – Bourke made use of this feature to obtain a ratio of approximately 3:1 (conventional two-strokes are around 1.3 to 1.5:1). When the transfer ports open, the pressure ratio was above the critical (Po/P = .528) thus choked flow occurred during the initial portion of the scavenge phase. The effect was that transferring fuel mixture short circuited right over the top of the piston deflector and out the open exhaust ports, without properly scavenging the cylinder of exhaust residual. Such a process could never result in the low fuel specifics and low exhaust emissions that Bourke claimed.
4) Vibration of this engine was indeed severe. Bourke 100% rotationally balanced the crankshaft without incorporating a reciprocating balance factor, thus all reciprocating forces were unresolved. Later, my engine’s counterweighting was altered to incorporate a 50% reciprocating balance factor. This made for somewhat tolerable vibration, but still not acceptable for a production machine.
5) Shearing of driveline components, which Bourke touted as high power potential, was actually high cyclic torsional inputs into the drive system. Bourke claimed that running a flywheel on his engine was detrimental to performance. I found that a flywheel was an absolute necessity to keep the dynamometer coupling in one piece.
6) Bourke states that the scotch yoke allows for a longer piston dwell time at TDC, thereby inducing the hydrogen/oxygen combustion process. He also states that the inherent straight-line motion allows for better resistance to failure when operating under detonation. As combustion was found not to differ from a more conventional engine, these claims are without merit.
7) The poor air delivery ratio was the result of both restrictive cylinder porting and lack of any induction or exhaust tuning. Cylinders were of the cross-scavenged type with drilled inlet, transfer and exhaust ports. The design was very similar to outboard motor technology of 1930’s vintage.

Heat energy liberated in the combustion of hydrocarbon fuels is determined by classic bomb calorimeter experiments. Here a known mass of fuel is burned in the presence of pure oxygen in excess. Virtually all of the fuel is consumed, the reaction goes to full completion, and results are therefore highly consistent and repeatable. Flame rates in the combustion bomb are the same as those encountered in engine cylinders when detonation occurs, this being due to combustion occurring in a pure oxygen environment. The conclusion is that there is no scientific possibility that more energy can be extracted from a given hydrocarbon fuel than that determined in the aforementioned experiment. As heat and work are mutually convertible quantities (Joule’s law), and knowing the fuel consumed during a given test, the engine performance can be predicted and checked against the dynamometer results. For this test, agreement was verified and indicated that approximately 9 BHP was all that was attainable.

Knowing the work out at the crankshaft, assuming realistic operational efficiencies and combustion being complete at TDC, and knowing the physical geometry of the engine, one can quite accurately calculate the temperature of the exhaust gasses when the exhaust ports open using a polytropic expansion relation. Had Bourke’s engine produced 76 horsepower at 10,000 rpm, exhaust gasses would be more like 1100 deg F, much higher than the claimed 200 deg. But as stated previously, the cool exhaust gasses were the result of poor scavenging, not from any magical combustion phenomena, and thus wrongly interpreted by Bourke.

As the engine’s delivery ratio was falling off sharply after 4000 rpm (and only 40% maximum), there is no possible way that it could ever turn up to 10,000 rpm. This effect, combined with poor charge trapping (due to the highly deficient scavenging), would never allow the high rpm, power outputs, or thermal efficiency to be obtained as Bourke stated. Air is the working fluid for any internal combustion engine – it is the properties of air expanding when heated that produces work on the pistons. If deficient air moving and trapping is occurring, as was evident in the tests, it would be impossible for the engine to ever approach the performance claims that the inventor made.

As it was the Experimental Aircraft Association whose publications brought the Bourke engine to my attention originally, I thought it honorable to write an article on my findings and publish it in their monthly magazine. A seven-page article was prepared, written in a style that was understandable by non-engineers, and that discussed the abysmal performance this engine exhibited under actual testing. A copy of this article is available at:

http://a.moirier.free.fr/Moteur/Documentation/Performance testing a 30 cubic inch bourke engine.pdf

I received letters from readers for years afterwards, most of whom praised the fact that the engine was actually evaluated and the truth told. There were some, however, who thought I just didn’t discover the “secret” that would make the engine run as Bourke claimed. And interestingly, I met several people who actually had experience with original Bourke engines. Their comments added credence to my findings.

It is this writer’s opinion that the Bourke engine was a product of an overenthusiastic inventor who made unsubstantiated claims of high performance and fuel efficiency, mainly to draw attention to his invention in the hopes of acquiring developmental funding. Until validated test data can prove otherwise, this engine offers no revolutionary benefits and is not a valid contribution to internal combustion engine technology.

 

[SwinnyGG]

Interesting post Dave, thank you for the original background.

Not sure if you read this whole thread, but your original article is linked a few posts above your reply.

I see you may have joined our forum just to reply to this thread- did someone reach out to you or did you find this thread via a search for discussion on Bourke?

 

[Dave Kirk]

Hi jgKRI,

Thank you for the kind remarks. I joined the group because of a member informing me about the Bourke engine thread. After viewing the contents of this website, I think this will be a valuable informational source on engines and things mechanical and look forward to being a participant.

I'm a retired mechanical engineer that has worked in the internal combustion engine field for all of my 34 year career. Since retirement, I've started doing engine consulting and really enjoy being out of the Corporate America rat-race.

I'm sure there will be those that feel that my tests were poorly done, that I made "changes to Bourke's exacting specifications", used the wrong fuels, wrong carburetor, etc. I've always found it interesting that these folks have little or no experience in the internal combustion engine field and just take the claims made by Bourke to be proven facts. I've yet to see any test data from anyone that substantiates any of Bourke's claims as to performance, thermal efficiency or exhaust emissions under a loaded condition. Until I can see actual test data that that shows otherwise, I'm standing by my findings.

As the old saying goes, "Show Me The Data".

 

[RVAmeche]

If your tests (and others) had been somewhere in the ballpark, maybe Bourke's ideas would have some credence. But the fact that real life vs his claims were so far apart, as well as the lack of actual data/results provided by him, show that it's just a tall tale.

 

[BrianPetersen]

Dave Kirk ... Welcome!

We've had our share of inventors show up over the years. Feel free to debunk as you see fit.

 

[RodRico]

Welcome Dave Kirk!

 

[Cryptoman]

The writer simply failed to achieve the Bourke Cycle! Simple as that. Plenty have failed and some have achieved it, evidently.
I know of others who have achieved powering a load with the Bourke engine, to what extent I do not know as I was not an eye witness.
I have yet to personally witness Bourke's claims regarding it's alleged power curve which is superior to any piston slapper ever made!
The man's claims about the scotch yoke being irrelivant say nothing but pure counter intention based on the need to be right about the flawed direct coupling of piston slappers. The Scotch Yoke is superior to conventional hands down! The resulting sinusoidal operation is a plus point and any engineer worth his salt will agree!
Don't get me wrong. I like piston engines of all types. The Dynacam engine and others that utilize various different forms of reverse cam arrangement prove it's viability!
Russell was into producing an engine type that required few parts and zero parasitic losses of multiple moving parts such as is the case with most piston slappers.
One thing I will note is using pump gasoline or diesel will not yield the Bourke Cycle!
Russell states this clearly in this documentary and explains why that is and anyone familiar with fuel doping agents can understand this.
As to his assertions on low EGT's being an indication of intake gasses passing dead across the cylinder directly to the exhaust port. WRONG!
Roger's prototye which I have personally witnessed ran on 50:1 premix just to be safe as it's not easy getting hold of replacement parts, yielded no smoke out of the exhaust ports. Squirting 30 weight motor oil right down the carburetor yielded no smoke out of the exhaust ports! Complete combustion? Hmmmm....scratch your chins on that!
The 001 and 015 original Bourke 30's both ran on pump gas which is not recommended but expedient, and did not use any pre-mix oiling. Proof that the crankcase oiling system works just fine as reported by Russell Bourke.
Anyway, absolute conclusive findings have not yet been achieved, no matter how much someone writes about it.
This guy could have taken video of his experiments back then. I wonder why he didn't given the time and expense of the experiments he allegidly performed, he surely could afford to buy a movie camera!
One thing still holds true today, the Bourke Cycle concerns those who stand to lose billions if it's mass produced!
And the potential for success still exists! Who's next to try?
Yeah, I could try to do it myself, and I still may! I do want to know one way or the other if the Bourke Cycle is a myth or is indeed real just like Russell said it is!
And finally, WATCH! >>>>>

http://bourke-engine.com/vids/Bourke30Runs.mpg

http://bourke-engine.com/vids/rlyruns.mpg

Like one piston slapper head said to Russ long ago, "we'll spend millions to prove you wrong but not one penny to prove you right!" H E L L O ! ! ! !
GodSpeed!

 

[SwinnyGG]

I have yet to personally witness Bourke's claims regarding it's alleged power curve

Then why do you believe them

One thing I will note is using pump gasoline or diesel will not yield the Bourke Cycle!

The 001 and 015 original Bourke 30's both ran on pump gas

Which is it?

I do want to know one way or the other if the Bourke Cycle is a myth or is indeed real

Soooooo people who have done actual physical testing are idiots who don't know anything, but if you ran a test you'd be the expert who knows everything?

I politely suggest that you put your money where your mouth is and run a test (as others have done) or stop promoting an argument completely unsupported by data of any kind.

While you're thinking about that, google 'logical fallacy no true Scotsman'

 

[btrueblood]

"The writer simply failed to achieve the Bourke Cycle! Simple as that. Plenty have failed and some have achieved it, evidently."

Funny how those who achieve it don't write about and provide data showing the results (dyno testing) from a reputable 3rd party lab. I guess they are just too busy making other magical things happen?

I'm going back to my pannetone, this fruit cake leaves a bad taste in my mouth.

 

[Cryptoman]

"We'll spend millions to provve you wrong, but not a penny to prove you right!"
Russell Bourke
Still rings true today!

You mean to tell me, after reading the Bourke Engine Documentary, UNlESS you haven't
and are relying on your piston slapper education, you actually believe it never worked as purported by Russell Bourke? What about eye witnesses? What about people that actually knew him personally and worked with him and saw these engines run?

What about the Bourke 400 truck / tug boat prototype engine?

Do you geniuses actually believe he and his investors would do all that work, spend all that money and try to make it go world wide just to create a hoax? Just to be right about bullshit? That they would all sacrafice and go through the growing pains required to push something of this magnitude forward to fruition? None of these people were rich. They were good hard working Americans earning a living and helping thier fellows while persuing their dreams doing something they had a passion for!?

LOGIC!?!? gentlemen, and ladies..

Here's an interesting thing to ponder. What would you do if you wanted to come up with something superior to a conventional naturally innefficient piston slapper that isn't trying to cock itself up or throw parts scattering?

Someone earlier stated that HCCI is impossible in so many words..WRONG!

https://arstechnica.com/cars/2017/0...ng-awaited-breakthrough-in-engine-technology/

I'll be back to play somemore later!
Enjoy!

 

[BrianPetersen]

Mazda's Skyactiv-X is not true HCCI. It's spark-ignition with essentially controlled detonation, facilitated by their direct-injection strategy, which allows them to create a stratified charge in the cylinder (roughly stoichiometric or slightly rich near the spark plug so that the spark plug can reliably ignite it, lean elsewhere but in a progressive manner so that the rate of pressure rise can be controlled and kept below destructive levels). The Bourke engine is a carbureted spark-ignition two-stroke ... evidently with enough compression to cause uncontrolled detonation. It is incapable of having stratified charge.

Once again ... Show us the P-V diagram, show us the means of ignition (and I saw those spark plugs), and how ignition is reliably achieved over the entire useful range of ambient temperature, engine temperature, and engine load.

At the moment, Dave Kirk's post indicates that the engine operates as expected ... not well.

 

[BrianPetersen]

I should add that there is no "Bourke cycle". The engine operates on the two-stroke Otto cycle, but with high parasitic loss due to the high pre-compression used in the scavenging pump (the work of which is lost during scavenging of the power cylinder), and evidently with an attempt to achieve the constant-volume combustion of the true Otto cycle as opposed to having a progressive combustion process (differing from the idealized Otto cycle) that real-world spark-ignition engines use.

The Otto cycle does not care about the means by which the volume in the cylinder is varied as it goes through that cycle.

 

[Dave Kirk]

Cryptoman,

I direct this post to you as you made some observations that are totally correct.

I was not able to induce the “Bourke Cycle” in any of my testing. You suggest that the fuels I used were wrong. In the Bourke Engine Documentary, Russell Bourke mentions running engines on brown distillate. At the time, I tried to procure this chemical and could not find it. Talking to some fuel suppliers, I learned that this was a low-grade kerosene, sometimes referred to as “coal oil” (having a light brown coloration) and was no longer available. Bourke also states in the Documentary that low octane gasoline can be used. This was also tried, both in non-diluted form and with diesel fuel mixed to further lower the octane rating. I also tried Coleman lantern fuel, a non-leaded “white” gasoline, as what Roger Richard has recommended. The most intense detonation occurred using the gasoline/diesel mix – there was audible detonation occurring – not just pinging, but loud spark knock. My engine lost power and would have probably seized had I let this continue as oil temperature was approaching 300 deg F. Leaning the mixture and advancing spark timing, either separately or simultaneously, caused a further drop in power. This was not a 1-shot attempt – I spent many hours in the lab experimenting with fuel mixes and settings, with never a hint of a “Bourke Cycle”.

Regarding the scotch yoke crank mechanism, you are again totally correct – there is inherently nothing wrong with this device. It has been used on marine steam engines and more recently, a high-volume production automotive refrigeration compressor (Tecumseh Products). The Ficht company, a German corporation (and the inventors of the direct fuel injection system used by Bombardier on their DI 2-stroke outboards) have been dabbling with scotch yoke two-stroke engines for years as shown in this YouTube video:

https://www.youtube.com/watch?v=2-25aj82Nuc

The CMC group out of Australia have done some very good work in developing a 4-stroke scotch yoke engine for automotive applications. Their research work has been top-notch and is available in several technical papers from SAE. The scotch yoke does reduce the package volume of the engine somewhat when compared to the conventional connecting rod crank system. There are little or no performance gains however. Their 4-cylinder engine does incorporate a balance shaft to cancel the primary couple induced by the 180-degree crank arrangement of the opposed configuration. And, the scotch yoke/piston assembly probably costs 4X (estimated, based on experience) than that of two conventional rods and pistons to produce. So, I can understand why automakers are reluctant to adopt this technology – more expense with the only benefit being a very slight package volume reduction.

The DynaCam engine – a barrel-form axial cam engine that has been around since the late 1940’s (then known as the Hermann Cam Engine). This machine has been constructed, prototype tested, received FAA certification and has actually been flown in a Piper aircraft. The packaging is very attractive in that frontal area is small, thus ideal for aircraft applications. After all these years, it’s never made it into production. Reasons are mechanical noise – the necessary clearance between piston rollers and cam surface generates a loud “rattle” when the engine runs. Mechanical efficiency is not very high due to high piston skirt loading and resulting friction caused by the double sinusoidal cam shape employed. Finally, cam surface spalling in a relatively short running time due to the high Hertzian contact stresses induced from line contact from the piston rollers. I’m not fabricating these defects…this was told to me by an engineer that worked for the company years ago.

Bourke Cycle low EGT’s – When I did the testing and evaluation of my Vaux engine, I was working as a mechanical engineer at Outboard Marine Corp – my first engineering job after graduation. Management was kind enough to allow me a test cell equipped with a Stuska water brake dynamometer and all the test equipment I requested, as long as I did my work after hours or on weekends. I had plenty of technical volunteers that helped with the testing and data taking. I utilized the exhaust emissions equipment to analyze exhaust products and a Merium laminar element for induction airflow measurement. When running the Vaux engine at light or no load, emissions looked like any other 2-stroke engine…moderate levels of HC, low CO and NOx. When dyno load was applied and throttle opened and ignition timing and mixture optimized, the HC (hydrocarbon) emissions went totally off-scale! It is true that EGT’s were only around 200 deg F and the engine was not misfiring. The only logical conclusion is that unburned fuel mixture was escaping to exhaust due to scavenge losses. This would dilute the exhaust gas and account for the low temperatures observed.

You are correct again in stating that “absolute conclusive findings have not been achieved”. Bourke’s first engine was constructed and ran in 1932 (Silver Eagle) and we are coming up on 87 years with no real test data on any Bourke engine to verify the claimed performance. Other than the outboard motor that Bourke stated to have logged “over 2000 hours of testing”, there is no vehicle installation of a Bourke engine that I know of as being successful and actually demonstrating the engine as a useful prime mover. This raises a bit of suspicion in its validity.

Taking movies – No movies were taken of my testing. I didn’t have a movie camera at the time and movies were not typically made of engines being dyno tested. I do have some still photos of the engine and test set-up, one of which appears in my original article in Sport Aviation Magazine.

When you state “One thing still holds true today, the Bourke Cycle concerns those who stand to lose billions if it's mass produced!” sounds a bit conspiratorial. If it were legitimate, I think the Chinese would be producing Bourke engines by the millions and selling them to us in automobiles.

I watched the video of the original Bourke 30 running on the 90-degree angle drive. The engine is running no-load and I’d estimate turning about 3000 rpm. The exhaust gasses are clear with no smoke and there is no fuel spit-back from the carburetor. The sound brought back memories – sounded exactly like my Vaux engine when running unloaded. I hope the next video shows the engine actually under load, driving a dyno, generator, prop, etc. Then you’ll notice a total change in the engine’s personality – severe vibration, carburetor fuel spit-back, and dangerously high engine oil temperatures.

Please understand that I mean no disrespect to anyone, living or dead, by posting my test results and opinions on the Bourke engine. If you are a friend of Roger Richard, please encourage him to run performance tests and post them on the Bourke Engine Website. I respect Roger in his dedicated and untiring faith in the Bourke engine. The fact that he’s constructed an engine from scratch plus purchased original Bourke 30’s shows his commitment and I admire that. I visit his site occasionally and never find any test results - only remarks that the engine is running a generator and producing around 30 horsepower. This is not conclusive test data – a real dyno-generated power (or torque) vs rpm and fuel consumed vs power information is the minimal, final proof that the engine is legitimate.

When I began my test and evaluation of the Bourke engine, I was very much convinced that there was something to be uncovered in this machine. I was a total proponent of the combustion phenomena that yielded hitherto unharnessed energy that could be controlled by a two-stroke engine cycle using a scotch yoke crank mechanism. In other words, I read the Bourke Engine Documentary and bought the pitch. I tested my engine to the best of my ability, working with others in the engine field, and working in a fully-equipped engine test lab. I reworked my Vaux replica to be exactly like the original Bourke 30 from Bourke-drawn blueprints. Most all of the costs for this entire project were on me – and it wasn’t cheap! I gave it a fair and unbiased evaluation and bottom line – it performed nothing like what Bourke had claimed.

I’ve always considered myself as an “engine guy”. It is my lifelong fascination with engines that compelled me to get my ME degree and spend my whole working career in the engine business. So, I guess I qualify as a “piston slapper” to which I am honored. I’ve also worked on turbo machinery and rotary engines, so “turbo-turd” and “Wankel whacko” apply as well.

Cryptoman – Please let us know your educational background and your experience with engines. It just helps us all better understand your passion for the Bourke engine.

Respectfully,

Dave

 

[Cryptoman]

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

 

[Cryptoman]

Ahl, beh bach!

 

[enginesrus]

Glad to have a fellow engine guy join, and wow a huge asset to this site. Welcome Dave Kirk.