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Originally Posted by GreenHornet
Its popcorn time everyone 
Now looking at the engine from an emissions perspective it is my opinion that it would show decreases in all levels except NOx. This is the Achilles heal of the HCCI engines of today. |
Actually HCCI has lower NOx emissions than a diesel which is why it is attractive to car makers.
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The Bourke design is for all intent and purposes an HCCI engine that helped pave the way for modern designs. So it would not surprise me one bit if we were able to test a prototype and see elevated levels of NOx similar to what we find today in modern HCCI engines. When you run an engine lean this is what you get and this is the reason we do not see these engines to often currently. Honda has lean fuel burning engine technology such as in there Insight Gen1. They can use it because they provide proper catalyst technology to help keep the NOx emissions in check.
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The main effort to control NOx is to not generate it in the first place. Trying to remove in the exhaust creates back pressure and eats in to fuel economy not to mention costs more money and adds weight to the car.
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The mechanical weak link has always been considered the scotch yoke. Many have tried to overcome and improve upon this and have failed. As of recent there are a few who have succeeded in improving upon the design. The article links below detail just how they improved upon the Bourke design and its significance. These two engine designers obviously feel that the Bourke engine was more than just a scam or lost cause! You can also see my thread how to increase diesel engine efficiency where Mr. Pattakon was kind enough to post more about his genius engine designs.
#1. Advanced Technology for Piston Engines
#2. http://www.pattakon.com/pattakonOPRE2.htm
Again I am going to throw this out when something is not well understood people will be quick to judge and often discredit. When things don't go as planned people tend to give up and throw in the towel way to soon! The Bourke engine is not perfect nothing ever is! I could write a page on how inefficient our current gas and or diesel engines are. However we spend millions on improving them every year! The 2 inventors I provided article links for above believe conventional engine design can be improved upon as do I. What is interesting is they both used the simple Bourke engine design and principles as a basis for conventional improvement go figure!
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Things are well understood about the scotch yoke. Collins Motor Corporation built a few engines based on their "improved" scotch yoke design in the 90's. They made a big deal about how it made a more compact engine with less vibration and danced all around to avoid talking about what a fuel guzzler it was and its emissions in SAE papers. For their comparisons they used simulated conventional engine designs that showed much higher fuel consumption and emissions than was being achieved with real engines of the day. Needless to say the hype didn't hold up, people got wise, investor money dried up, they went broke, and nothing became of their technology.
Sinusoidal piston motion and extended dwell time at TDC is not a way to save fuel but just a way to waste it.
Any company associating itself with the bourke engine is a scam. They can't get conventional development funding because science and actual experimental results show it won't work out the way they say it does. So how do they get funding for it? They bilk dreamers with false claims of being repressed and accept donations.
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The Bourke engine has more than just an incredible short list of parts going for it. The engine can idle extremely low and have almost instant power.
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A 19th century steam engine can idle at a complete stop and have instant power but that doesn't make it efficient.
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The engine is not dictated by RPM but rather engine load similar to what you would find in an electric motor. At idle it uses a very small amount of fuel unlike our conventional engines.
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You made me spit water out of my mouth from laughing at this claim.
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The engine can run very lean and to very high rpm. The engine can run a plethora of fuels
( Readily dissproven hype and double speak omitted )
However there are limitations and areas that need worked on and improved that the people who have worked and experimented with these engines will tell you. They will also tell you that even Mr. Bourke new it had limitations and was quietly working on improvements as most all great inventors do. He ran out of time before he could implement his improvements. Had he had more time who knows where we could be today!
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I know where he would be. He would be hyping the Bourke engine with a bunch of other scammers because his patents ran out.
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Engine control and fuel injection are 2 areas that could really use improvement with the Bourke engine and modern fuel injection has matured to the point this could definitely be a possibility. Also engine electronics has improved and matured as well so this could have potential in helping control the Bourke design.
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This still won't fix the problems of wasting energy compressing the intake charge twice and extracting power only once or wasted heat due to extended dwell time at TDC.
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Now a few things I would like to make clear. First I am no engine design expert and second I am no Bourke engine expert either. I have come to my own opinions and conclusions from research not only from internet readings but also by talking with people who have far more experience in engine design than I as well as people who have first hand knowledge and experience in Bourke engines and the like.
Does the Bourke Engine deserve the Unicorn Corral maybe for some but for me I think it has much potential and sometimes it takes looking out of the box to see such potential. I can appreciate others opinions such as ConnClark and he brings up very valid arguments. Good arguments are constructive for improvement in anything and is something I highly value.
At this point I am so immersed into my kit car project Tigon that there is no way I have the time to build a prototype engine and perform testing to help us gain better knowledge into its claims. However once the car is complete and tested I will have much more time on my hands and would be willing to put my time and energy into such a task of helping us to understand the Bourke engine design much better. Until then the best I can do is talk to others and try to gain insight that way. Which to this point has showed me that The Bourke engine design is very real and not a scam. Also that it has helped us gain valuable insight to HCCI design and other engine design platforms that will help us to improve our current conventional engine designs and theories way into the future.
Oh and as far as the point about poor piston ring lubrication which I did not forget to mention btw because they are more than adequately supplied with oil by a small hole in the cylinder wall at bottom dead center  However I do love the Frantz by pass oil filter for our current conventional engines and will utilize it in my small 2 cylinder diesel in my Tigon hybrid design...
GH 
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Regardless of the location of the lubrication hole it will still be exposed to blow by from the piston rings and that is going to contaminate the oil. A small hole might mitigate it to some degree but will likely foul and plug up.
The patents on this engine have been expired for decades. No one has made it work to be competitive with existing decades old technology. Glaring flaws from an efficiency stand point cannot be overcome to make it work efficiently. Getting rid of the flaws means omitting the scotch yoke and the compression of the intake charge by the piston. Doing so leaves you with a conventional two stroke with scavenging done by an external blower which is no longer a Bourke engine and thus has promise.
If you want something that is considered thinking out of the box try a rotary Atkinson cycle engine. It has thermodynamics working in its favor.
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