Engine Concepts...

I thought we needed a engine concepts thread.

Recently a gentleman posted a thread on a conventional piston engine he had developed for marine use. It was loosely based on the Ricardo Tank engine of WW1 which was very successful but never fully exploited. In fact the crosshead piston was not incorporated in the engine thread previously posted. I think that was a significant advantage to the Ricardo engine that could have been exploited better in a marine diesel.

My interest in engines goes way back to childhood. In days now gone I devoted much of the free I had not related to my real business ventures... including much time money to helping newer ideas long. Those days are gone for me and I could have afford several nice maxi sail boats for what was spent for no good gain.

I can assure you most everything mechanically has been done. The real frontier is in thermo and combustion control. Having some long term stock holder relations with CAT I am always interested. CAT awhile back, about 12 years ago, had problems with many of their over the road engines not actually meeting USA EPA qualifications (claimed they did but didn't). This caused for a few years them to pay a in USA dollars fines of 10,000.00 dollars per engine sold. The deal with the EPA was they would fix the problem with their newer engines and conduct research into other emission control technologies... 1/2 funded by CAT. One of these was a cam engine which used an in-cylinder ceramic regenerator. The idea was the cam engine would allow the pistons to dwell for longer near top dead center to allow time for heat transfer.... cannot do with crank and rods. The cam was to be a axial cam as originally invented by Hans Herman who made cam engines for private aircraft in the 1950-60's. But this was not a sinusoidal piston movement. The project failed due to the ceramic regenerators clogging and breaking.

The point of that is the mechanical arrangement was solely for the thermal and emission benefits of the engine... nothing more.

But different concepts are interesting mechanically... here are a couple. The first is a swathe plate barrel engine that is very compact the swathe plate provides sinusoidal movement of the pistons. There Duke engines are quite similar to several engines similar to this that even were sold in production.
https://www.youtube.com/watch?v=c19kn3drdFU

Here is another one that is much like a wankel but in a ball shaped cylinder...
https://www.youtube.com/watch?v=eRhxctg5mns

Here is one that Detroit Diesel MTU and US Marine Corps spent about 22,000,000 dollars on in the early 1990s invented by Marius Paul with twin crankshafts... ran about 15 minutes at a time until the piston rings broke... project covered up everybody when Dr. Paul pulled a gun out and started waving at a meeting when the Marines and DDMTU were wondering why it only made 1/10th the power and about efficiency of a open fire... compared to the high 80% thermal efficiency he claimed and still broke engine rings...to to extreme combustion pressures.

Neander AG took up the mechanical concepts of Paul and developed this outboard engine:
Green Car Congress: FEV and Neander Motors AG showcasing double-crankshaft turbo-diesel outboard marine engine at SAE World Congress

Couldn't sleep this mourning got to thinking...

This Neander outboard is really neat.
http://www.neander-motors.com/tl_files/neander/newsletter/Neander Vortrag Aachen.pdf

This Neander Shark turbo diesel outboard takes me back. Romanian inventor/professor of Thermodynamics Marius Paul invented the twin crankshaft concept and his last engine [funded by a few million venture capital] had this 'floating ball' concept for the attachment of the pistons to the connecting rods. This Spring 2014 when this came out at the SAE conference I was happy to see it. I believe it validates much of Paul's work.

The concept was good but the people funding Marius Paul's last project were crooks and ended up getting about 700 million US dollars funding fraudulently... 95 percent of which they skimmed and spent as all these frauds are wasted. This situation killed his work on it, as he was in his seventies. Marius was typical of East Block professor technocrats and very inconsistent and innocently susceptible to schemes to further his work. I knew him and his wife Anna a little (she was a highly talented and educated engineer in her own right). Both of them went to school in Romania with Rodica Baranescu, Chief Engineer, the Navistar International Truck & Engine Corporation and later President of the SAE. Marius was a genius but bottom of the class guy.... Anna and Rodica were the number one and two students at the technical institute... and interestingly both dated Marius. Anna became chief engineer at (forget the name) Romanian State Thermo-machinary Technical Institute.

Sadly Paul never fully realized his inventions. He sold most of the turbo-machinary and thermodynamic inventions to United Technology... oh let's see about 2004-2005. I believe he resides in Southern California last I heard.

Marmot you are right. The spherical bearing has been used as a con-rod small end attachment to the piston, to rotate pistons and a host of other purposes.

Before I can explain a little as to the Paul and the Neander engines some background. Twin crankshafts have been around for a long time. The important thing as to the invention was it is a substitute cross-head to guide the piston, and the use the Neander exploits to balance the torque reaction forces on the engine... basically so the engine does not try to spin on its mounts.

[Paul needed it because his thermodynamic cycle he invented was basically the application of the Brayton cycle typically used for jet and turbine engines for a diesel reciprocator. Paul is a genius at understanding complex engine cycle theory and deriving the mathematical models... the mechanical aspects I believe were primarily Anna's concepts he adopted. How he intended to achieve this application of a diesel reciprocator was outside of the otto and diesel cycles was using very high mean specific pressures in the engine... 300 bar or so (4500 psi in English measure). No diesel engine even comes close to this. The internal pressures would be developed artificially with a secondary turbine / turbocharger. Simply the thing was intended to be run on around 10 bar boost (120-150 psi). I am not going to discuss the details of that as it is way beyond the forum. When I first met with him I did not understand but it really is unique and genius in how he planned to minimize the entropy problems. But I will say these Paul thermo-theories were put to good use and made the very advanced MIG 29 engine possible... a turbine... though the Russians were smart to keep him out of the engineering development aspect and get extremely talented engineers involved, people the caliber of his wife Anna and Rodica... as Dr. Paul was a theorist not an engineer.]

The idea of the twin cranks is balance, guiding the piston and reducing the bearing load in the Paul inventions. The problem was in the DDMTU project the test engine developed dynamic problems with slight piston rock which was fatal combined with the extreme high internal pressures... cause ring durability issues. The ball was to help solve this. The problem developed due to the effect of gearing dynamics in the gears tying the cranks together. In the last engine which project failed due to the money fraud problems he had tried to fix this with the ball and changes to the gearing, so it remained unproven.
The other issue is the sealing and piston rings durability. With any rocking (that a conventional diesel would typically see) this created problems with the rings. And, the rings were critical. I remember visiting with him on investment issues... which quickly devolved into him running his latest theories and calculations by me for comment. Anyway at that meeting, once the problems came out for discussion (something he hated) I suggested a spiral labyrinth ring set up that had been used in a very exotic engine project for NASA...
[That NASA project, I was on the board of the company doing the work... interesting that engine ran at incandescent temperature for heat rejection mainly by radiation (glowing orange)... not convection. In that the problem was the cylinder bores basically became a section of a cone of about a millimeter variation over the stroke length, necessitating the special sealing system. Interestingly, it worked very well once at temperature and was very durable but the real challenge was the startup... it could wear the engining out starting it up... oh by the way that engine did not use oil for lubrication.]

I think if the Neander engine works out and is commercially successful it has a lot of benefits for engines in general. The market for a good diesel lightweight vibration free outboard is big. Maybe some day we will see other uses.

Marmont, yes the peaks on the indicator card can be high but are very transient. Paul's those 300 bar were not "peak"!
Although, Paul would say it was a pre-production he had no idea what that meant. As I remember the Saudi's believed this and were hoping that it could be used for off grid power generation stations... one of the Princeses even mentioned a yacht application! However, much of the output would be off the associated turbine {read really big turbo chargers} it was always intended to be used with post exhaust gas treatment.

It was really in my mind an applied research project... which is to my mind a hobby investment due to the high risks involved.

We should move on to other more refined engines that might be practical. I don't think Paul is active anymore and his were mainly unrealized dreams.

One final comment before burring the Paul engine discussion... the Selden (check my spelling) car had a Brayton cycle engine... and was an impediment to Ford in the beginning and his car.

That Duke engine is very interesting as the Russians have used barrel engines in boats and submarines. The advantage of barrel engines is balance; number of firing pulses per cylinder per revolution output; compact size/power density per size and weight, and; service possibilities and perhaps in it all the liabilities!

Well it is my time of day to have a little break... listen to some music... have a refreshing drink... and maybe shine my boots.

The point of this thread in some ways refers to "engines" of the reciprocating piston variety. But for a long time now my hobby days are over on that score. Why is it is interesting but has little place to go. Certainly one can build a new improved engine that can compete in the commodity diesel or spark ignition markets but it is hard when you are up against the business curve... and mature technology. Lots of investment low reward. Risk is always manageable... in that look at the gentleman in the Duke engine thread he could be successful and would be if the investment were large enough to overcome the inertia he faces. Or, it was like the Neander Shark a very specialized niche market like diesel outboards... of less than 100 hp.... actually Neander with the right support from marketing, manufacture and service situation could really make a mark.

My posts on Marius Paul's piston engine are interesting to me because he was taking where Napier left off in piston engine development like the Nomad. Using the piston engine as a gas generator and efficiency modifying means of basically a turbine... to allow the grunt needed at low speeds and in transitions which a turbine is poor at... and importantly to increase thermal and energy conversion efficiency. But such schemes are expensive and complicated machinery. Paul's invention used a Brayton cycle with a very high pressure across the piston engine and a high temperature gradient across the turbine. In fact the thermal situation likely would have had the cylinder and piston exposed to too great of heat loading along with the pressure... if he had got further along... in my view.

Many years ago I helped a small company with a piston engine for general aviation... I thought it might be successful in a very niche market... but their dreams extended out of that and that is what killed it. As I said at the time, you may be able to beat a turbine or turbofan efficiency wise but the engine will be heavy and no-one is going to design a plane for that for you... for get putting it in commercial aviation use! Secondly, though the efficiency argument was attractive the situation was you either carried fuel for the turbines or carried around dead weight of the engines. Fuel burns off and reduces the weight but the engine is an anchor all the time. They forgot to look at overall takeoff to landing fuel per mile traveled... the heavier engine burned more than the turbine in the second half of any longer trip as the plane was heavier. So they were giving up the efficiency.

For some time I have been thinking of a power yacht, displacement type, powered by either turbine or fuel cell engines. I don't think fuel cell are quite up to the task. But turbines are. The issue is under 1000 KW turbines are primarily in shaft power used for aircraft applications or a part of an industrial electric power and steam producing system. By themselves they are very poor in efficiency to a modern diesel. And, the service costs are higher. So other than as something different it remains an afternoon thought. Now if one could have a compact system where the turbine waste heat made steam and that powered a reciprocating steam engine that might be the ticket... sort of like the now dead Voith waste heat recovery scheme for diesels. That seams interesting... and it could be very quiet in operation with little vibration... !

The marine pleasure boat market for outboards and small inboard is pretty large, but it is a niche market. And, the market segment that Neander is going after is a sub part of that. I think they have a winner if it works well and does not kill itself in "initial entry problems."

The marine market for the larger engines like the Buck discussed elsewhere is large in the commercial sense but tiny in the yacht sense. The CATs, MTUs and Mans have it well covered. But one could still enter it. The issue is in my mind whether to make it a boutique supplier to the yachties or make it a practical alternative to the commercial segment. The Buck seems to be geared towards the commercial side but more likely would achieve success in the boutique side. Frenchies are great at this... boutique side of things and the Germans are very good at the commercial side along with the Americans. CAT reins because of its worldwide service that is reasonably good. MTU is behind because as herein often discussed their service sucks and is expensive. Man is sort of between the two in service. But Man has a strategy of suppling and supporting boat builders well and giving discounts to install their engines. This works... but it is paid for by higher part and service costs. All that is my personal view... don't kill me for it!

The problem for the Buck and others is the commercial side is very pragmatic... a fisherman does not want to risk much as he is marginal anyway. A yacht owner is more open but does it really matter you can change a cylinder and piston quickly. I don't think to an owner that matters. Its like fuel consumption someone that owns a 30m that does 30 knots is not worrying about fuel consumption costs. An owner of a 50m yacht usually could care about the problems the crew has day to day in the engine room as long as it doesn't disturb his very rare vacation time off on the boat. That's super yachts its a boutique market.

But the larger segment that owns 10m to 20m boats or under is more pragmatic and especially the cruisers. But that is not the super yacht market either.

I don't know where engines like the Buck fit in. 80-100 years ago it was easier as people would buy from engineering companies engines. In the auto market most of the car brands in America were based in Indiana... before about 1920. Lots of small creative companies... even expending to 1930. Most of these bought engines from suppliers. Why Detroit took over is going to a mass market with a mass manufactured product was not supportable in Indiana as the banks were used to lending to farms with a 6 month note turn around. In Detroit they built cast iron stoves and that was applicable to an engine and other big components technically and the banks were used to lending to manufactures with a 5 year note cycle.... food for thought.