New Engine Design: Doyle Rotary

Adam,

What method would your Father use to cool the latest design? There is mention of both liquid and air cooling for the prototypes.

Hello Adam, and welcome to the forum.

We talked to your dad about this a little while ago. It sounds interesting.

Can you tell me, is there some particular application or market this engine is being developed for? Are there any SIGNIFICANT advantages to this versus the myriad of engine types already available?

The previous prototype and the next prototype are both oil cooled. The prototypes are mostly for proving the concepts and for preliminary tests so picking the easiest cooling method made sense. If the motor made it to market it would surely be water cooled.

The target market is automotive. The following advantages will explain why it would be great for cars.

We consider the size and mass of our motor to be a great advancement over the conventional engine. Our engine is 11.5 inches long and 18 inches in diameter with a working displacement of 4181 cc (~255 ci). When a bounding box is placed around our engine and around a small block chevy with a comparable displacement we find that our engine contains 1.5cc of displacement for every cubic inch of physical space while the small block chevy only contains .47cc per cubic inch of space. Our engine is more compact.

As for the mass, fully assembled the Doyle Rotary comes to 220.5 lbs. A 350 small block chevy weighs 685 lbs (http://www.enginefactory.com/chevdimensions.htm). You can see our engine is .86 lbs/CI while the chevy is 1.95 lbs/CI. Also concerning mass, the total rotating mass of our motor is 68 lbs while the total rotating mass of the chevy (crank:54, flywheel:35, and crank end of the rods:8) comes to 97 lbs. We might have to actually add weight to the rotating mass to increase the angular momentum.

The Doyle Rotary does not have a valve-train. So no energy is lost to turning the camshaft to open the valves. Instead of valves, ports are opened to the cylinders as the motor turns over. These ports open and close instantly rather than gradually opening and gradually closing like in a conventional engine. This increase the duration of wide open flow from the ports.

Our motor should have a higher fluid efficiency because the flow into and out of the motor is never interrupted. In a conventional engine air rushes through the intake while the intake valve is open. When the valve closes the air passage is abruptly closed and causes a pressure wave to bounce back up the intake, increasing turbulence in the runner. In our motor there are always two or more pistons pulling air in. The air passage is never blocked and flows continuously. The same holds true for the exhaust port.

You seem to think that just because it is smaller and lighter, it will be better.

What is your horsepower/torque ratio?

How does this engine withstand abuse and misuse?

How is the fuel economy under load?

How well does it handle adverse conditions? (extreme cold or extreme heat)

It is questions like this that auto manufacturers will ask.

We do not have any specific data for the engine. We can only attempt to qualitatively compare this engine to what already exists. We do not need to know numbers for how much better the engine could be. But by comparing each step of the combustion cycle we can determine whether the Doyle Rotary is better.

Intake:

Relative to a conventional engine, there are several factors that make the intake portion of the Doyle Rotary better. First some background: My dad worked for 15 years in R&D at a performance race engine shop working with cams, combustion chamber shapes, intake and header designs, and intake and exhaust port shapes and designs. To make an engine more efficient you want to increase airflow without increasing the cross-section area of the intake runner (increasing the c-s area of the runner can cause the air to stagnate). Our intake runner can have a very small c-s area without harming the flow rate because: 1. air is constantly being pulled through the intake runner (as mentioned earlier) and 2. because our intake runner is at its peak flow rate longer than conventional valves allow.

Also, because combustion never occurs in the intake cylinders the air being pulled in remains cooler (in a conventional engine the air coming in meets the post-exhaust-temperature and begins to heat up and expand). Cooler air is denser and contains more oxygen to help increase the power generated by the combustion.

Compression:

A flaw with having compression, combustion and power in a single cylinder is that to allow the fuel to completely burn, the air-fuel mixture has to be ignited before top dead center...while the piston is still compressing. For a small block chevy this means that 34 degrees before TDC the fuel is ignited and for that 34 degrees the piston is compressing against the flame front. Essentially, the motor is attempting to run backwards during this time. But this is necessary because the air-fuel mixture does not burn instantly and if the ignition occurred any later the piston would begin racing away from the combustion, significantly decreasing the usable amount of power. In our motor the combustion occurs in a separate combustion chamber and never fights against the compression piston.

Power and Exhaust:

In conventional engines the exhaust valve is opened prematurely to achieve proper valve timing and to use some of the power pressure to jump-start the exhaust flow. This means a portion of the power generated by combustion exits directly out of the exhaust and is not used for work. In the Doyle Rotary the exhaust port does not open until after the power piston reaches BDC. This is acceptable because there is a constant flow of exhaust (because there are always at least two pistons exhausting) and because the port can remain open until the piston reaches TDC and completely forces out all of the exhaust.

It seems logical to assume that if the engine is of the same displacement and has all of these advantages through each step plus the lack of a valve-train, it should be more powerful and more fuel efficient than the conventional design. However, the only way to really know is to build and test a prototype.

As for durability and operation in adverse conditions, the best we could figure would be through finite-element analysis (just like engine manufacturers). But realistically, our engine should be as durable as what is currently out there because we are using parts and technologies that have been used in other engines. Once again, building and testing a prototype is the only way to really know.

Your comparisons are all well and good. However, hard facts are what are needed to prove your engine to be better. Even if each aspect is better, they are still only theories till they are proven. the only way to prove them is to test a working model and examine the results.

Logic only computes in mathematics. Time and Time again things in this world are rock solid on paper then turn to mush in the real world.

Mother Nature is a professional in the art of sabotage.

This is quite interesting. Before anyone dismisses this idea as "never being able to beat a chevy smallblock" it is important to remember that there is a very wide application range for internal combustion engines and similar positive displacement devices. It's pretty hard at this point to see where this is one is going. But note: Many have followed this quest before. Few have succeeded. Far to many have disappeared into the obscurity of forgotten patents and old technical articles that their collectors cannot begin to understand.

First thing that hits me is that the center combustion chamber area will get fairly hot. At the same time there will have to be innovative sealing technology to insure that leakage of combustion gasses through the moving joint are minimized. This will require close clearances and precision surfaces. There is liable to be some incompatibility between this requiremment and the potential temperatures in that region of the engine.

I will watch this thread and Hope I can offer something other than discouragement.

BTW, there is a fellow in Oz who never got all the Dynastar engine SAE paper copies I promised to send him. Not enough round tuits on my side of the mountain. A little prodding might be in order from his direction and mea culpas from mine.

Ed Weldon

To alleviate the thermal gradient between the intake side and the power side, the power pistons, power ports and combustion chamber will all be coated with a ceramic coating that we have used before on sprint car engines. The goal of the ceramic coating is to lower the amount of heat absorbed into any piece of the motor so that as much heat as possible is used for work. After being used as a power source, the excess heat will exit the system through the exhaust port. ny heat that isn't absorbed helps to keep the temperature in the combustion chamber and power cylinder as low as possible. To help diminish the temperature gradient even more, the water cooling system will travel from the hot side to the cool side to distribute the heat.

As for sealing technologies, we will be using the standard apex, corner and side seals from the Wankel engine. The sealing surfaces will be machined out of the same material and to the exact dimensions and tolerances used in working Wankel engines. The surface will then be honed to the same Ra finish, plated and hardened to the same Rockwell hardness as the sealing surfaces in the Wankel. The seals will be subject to the same forces as the seals in the Wankel (direction and magnitude) and will function exactly the same. We feel that using proven technology drastically diminishes the chance for failure.

We have put years of thought and energy into this motor and hope that it does not follow the path of the forgotten patents.

Even though I have been kinda harsh about my comments and questions, I genuinely hope you have the best of luck in making this idea work.

This is an intriguing concept, and I think you and your father have explained it well. The advantages you cite seem plausible (in particular by not being hyped), but they may hard to quantify by calculation. Thus the proof of the pudding will be in measurement (testing the prototypes). Dynamometer, alternation of idling (cool) and maximum (hot) cycles, and durability. I too will enjoy following the progress of this. It's quite elegant, and I'd love to see it work out. Good job on the graphics and Website appearance also.

Thanks for the compliments about our graphics and website. Animation and website design pulled us a little out of our comfort zone.

Our next step is to hire a professional to do a very nice animation (the pro's work can be seen here: http://www.youtube.com/watch?v=jAVLmWR8ZfM ). We hope that we can use the professional video to get grants or investments to get us in the door at a national research institute.

Five months ago, my dad took a check for $20,000 on a four and a half hour drive to a scheduled appointment with Rainer Rothbauer, a research engineer in: Advanced Combustion and Emissions, Engine and Vehicle R&D, Engine, Emissions and Vehicle Research Division, at SouthWest Research Institute in San Antonio. My parents spent the night in a hotel for the appointment the next morning.

At the meeting with Mr. Rothbauer, my dad explained the motor to him verbally along with the 3D models and an animation. While explaining the motor, my dad occasionally got the feeling that he did not have Mr. Rothbauer's full attention. After 20 minutes of explaining the motor, Mr. Rothbauer asked how the engine would be sealed. My dad answered: Mazda seals. Mr. Rothbauer replied that Mazda seals do not work. My dad said that they work in production vehicles on the roads today. Then my dad was asked: "How are you going to get air into it? Are you going to use shop compressed air?" This is when my dad decided that his $20,000 might be better spent elsewhere.

We had hoped to have a team of thermodynamic researchers analyze the motor using CFD software to determine the optimal shape and size of the ports and combustion chamber for our prototype.

What happens to the centre of mass of the piston assembly as it rotates? Reducing this movement to a minimum will be the key to the success or failure of this idea.

After seing the pictures and the video:

- Very interesting concept. It surely removes the shocks and rough rides that comes with a crank shaft - piston normalengine.

- Concerns: Moving parts in the pistons are the same.

The cranck-shaft bearings were easier to handle than what seems to me (might be wrong though) the seals, two rotors etc bearings(?). I can't see more than that from the illustrations...

You have Cylinders, Pistons, Connecting rods and the two masses (in & out) all rotating == shaking, vibrations, centrifugal forces... Is all this rattling somehow? or the noises generated high? Can't imagine the whole running quiet.

Conventional piston engines do make a lot of noise but the main source would be the explosion noises coming from the exhaust. Here, How quiet is the overall noise generation? (Compare like to like).

As pointed out by previous threads, the wear and tear aspect will need to be looked at. The concept is beautiful but the transmission seems to be the area that will make it or break it.

Really, Good Luck and I hope it will work efficiently.

The connecting rods and pistons still have the same parts causing friction: the wrist pin and outer end of the rod float on a pressurized film of oil and the pistons have 3 sets of rings (just like in a conventional engine). So the counteracting force generated by friction from the pistons and rods is similar for our engine and a conventional engine.

This afternoon I will be creating a couple more animations to illustrate how the seals and bearings are oriented around the crankshaft. They will help show how everything works. But I will try to explain the bearing surfaces here. The crank shaft supports the cylinder block with a plain bearing on each end. On a separate axis, the crank also supports the outer housing with two plain bearings.

Because the cylinder block and outer housing both rotate around fixed axes, the motor is super smooth while rotating. The swept volume of the pistons is a result of the outer housing and cylinder block being on offset axes. Also, the pistons rotate about a fixed axis that is halfway between the axis of the outer housing and the cylinder block. Their center of mass is fixed at that same axis. Therefore, there is no reciprocation of mass and no rattling, or noise, will occur.

The noise generated by conventional engines occurs when the exhaust valve opens while there is still tremendous pressure within the cylinder. This pressure causes air to rapidly escape around the valve. This rapid expansion is what you actually hear as noise. In the Doyle Rotary, the exhaust port opens after the power piston reaches BDC. There is not as much residual pressure in the cylinder, so the rapid expansion of gases from the exhaust is not as dramatic. So the Doyle Rotary has the potential to be quieter.

Adam,

If no prototype has yet been done:

- Since the piston - rod assembly is moving the outer shell in one direction, the inner cylinder block will tend to move in the opposite direction... the resulting force will dictate the motion direction. (?)

- I think that this is a point to look at from the dynamics side and explain the interactions.

In a conventional IC engine with normal rotating crank, the shaft is the only rotating item while the piston moves in the vertical plain. The Cylinder Block is fixed (bolted down or weight...) and the piston-rod assembly has a definite movement direction.

Here, there is a little more work out needed to properly define the motion in a real life (as oppased to animation) engine.

I hope I was Clear.

True, a powerful engine would tend to torque the vehicle as power is applied to the road. This would be bad for a motorcycle or aircraft, but could be compensated by using two counterotating sets of piston assemblies.

Drew

The magnitude of torque of the vehicle increases as the rotating mass of the motor increases. The rotating mass of our motor (68 lbs) is not greater than the rotating mass of a comparably sized conventional engine (add up the flywheel, crank and big end of the rods). So there will not be an increase in the amount of torque twisting the vehicle around.

Also, sorry for the delay in responses. We have not had internet access for nearly 5 days now.

An interesting thought would be to transverse mount it into a front wheel drive and set it so that the torque applies its torque to the front wheels increasing traction. (would that work?)

Would be interesting on a motorcycle, transverse mounted wheelie inhibitor!

Drew

It sounds as though it will also make a good small aircraft engine if the power output is good....light, powerful and hopefully reliable......

Best wishes, keep us up to date please.

Good luck! Looks like way too many moving parts for my taste, but if it works, great.

I have posted a video that should help explain how the Mazda seals are used in our engine.

http://www.youtube.com/watch?v=eIQTaZb-ZDA

These Mazda seals lead us to a possible disadvantage of the motor. In the Wankel, oil injectors add oil in front of the seals to preserve the apex seals. Because this oil is injected into the combustion chamber, small amounts of oil are burned during normal operation. Burning oil not only increases negative emissions, it also increases running costs slightly (replacing the oil periodically). The Wankel has successfully passed emissions standards which shows that the amount of oil burned is relatively low. The emissions issues may not be as big of a factor for our motor though. This is because our seals are not required to follow a complicated irregular path. They slide against a perfectly round sealing surface. The seals in our motor should require less spring pressure to seal against the circular. Decreasing the pressure will lower the amount of friction on the seal and also lower the amount of oil needed to preserve the seal. So the negative emissions could be significantly lower than the Wankel.

If any questions remain, feel free to ask.

http://en.wikipedia.org/wiki/Radial_engine

http://www.dself.dsl.pipex.com/museum/POWER/unusualICeng/axial-ICeng/axial-IC.htm

...Wankel, your idea, and many more. I wish you good luck in an area where many unique and novel ideas have not been able to demonstrate a significant advantage over current state-of-the-art IC engines in most practical applications. Of course niche market applications are always a fall-back option.

http://www.dself.dsl.pipex.com/museum/POWER/unusualICeng/rotblocIC/rotblocIC.htm shows some other revolving-block engines, notably the Selwood-Hughes (ca. 1980), whose pistons traveled in toroid-segment "cylinders." It too was a swash-plate type.

Your main problem as I see it, is still that you appear to not have a working and running engine to show anyone after 20 odd years of development work.....

A video of a working engine would be far more effective than any number of simulations........

Then (sorry I have to say this!!) at this time, it sadly gives the impression of someone "fishing" for development money, for a completely unproved idea.......that will not impress the people with money in the slightest........

Please prove me completely and utterly wrong with a full working engine (of any size/number of cylinders) on YouTube.......

I still wish you the very best in your endeavours and hope that industry picks up on it.....

To the poster who complained that there are too many parts, please remember that conventional motors have also got similar numbers of parts (at least!!). I do not see that as a problem.......but not having a working example is.

Maybe one installed in a model plane or boat may be a good way to start and should be in the area of development costs that a small company can supply/allow for.....if its as good as you hope, you may find that selling working versions for model builders can give you eventually enough finance (and experience/knowledge) to build bigger/better versions........just my 2 Cents worth....

The reason that we have not been able to produce a functioning prototype over this many years is that we did not go fishing for funds. The six prototypes were funded out of my dad's pocket and machined by him in spare time. If you look at the evolution portion of our website you can see how he had to make stabs at motor development throughout the years.

The prototype that we are about to build is not the same engine that he thought of in 1985 or the engine that he built 7 years ago. In 2007 this new engine design idea (with inward facing pistons) was formed. This is the first design that he and I could not discover any strikingly obvious flaws. After three years of designing and studying this new motor, we still could not find a flaw that could stop the motor in its tracks. That is why we posted here. We do not have any schooling in engineering and understand that we could be way off on our ideas and hoped to get comments and criticisms from other people (we are very pleased at how many comments and questions we have been able to answer here in the forum).

Funding prototypes is not an issue anymore. My dad opened his own aerospace machine shop in 2004 and it is doing well. Because prototypes only cost $40,000 or so to build we can fund them ourselves. We have CNC mills for machining the parts and access to a race engine shop for testing.

The reason that we are not spending time or money on building a miniature prototype is that it would not put us any closer to showing a comparison to conventional engines. After spending a month or so building the miniature we would be back where we are now: preparing to build a full-scale prototype to test. If we were seeking funds, I could see why building a small-scale prototype would be worth it: to attract the attention of investors.

Time is our biggest issue building this prototype. I go to school 5 hours away so it leaves my dad fabricating and building the motor himself. The previous prototype took him 8 months to manufacture, so a good guess of time between now and a video showing a running motor is 8-10 months.

Have you video of any of the versions you have built running?

If yes, can we see it/them please?

I am most happy to hear that financing is not a problem (or not as much of a problem as I thought it might be!), really great to hear!!!

Although I find the project extremely interesting indeed personally and hope that you will continue to post for us, I am at a slight loss to understand what we can do for you in return.....

Also, until the patent is granted, surely you stand the risk of being copied, especially from the far east!!

I do think that a running version, with its continuous movement with as good as no reciprocation could well be a) long living, b) quiet, c) reliable, d) economical......

You may find that Synthetic oil will give you some good advantages too for lubrication.....I have used it for years in my car engines.....and no other additives!!

Best wishes....

We do not have any videos because in our excitement we forgot to record the motor before it seized. Next time we will have plenty of cameras.

Our plan: We will continue to make animations explaining various aspects of the motor until the whole motor has been described. Making these animations takes time but we will post as quickly as we can. We are posting these animations and descriptions hoping that a thermodynamics expert will watch them, really study the design and cycle of our engine and provide us with their expert opinion. We have been so focused on the engine that we might be viewing the engine in tunnel-vision and might have missed a crucial flaw in the design. It would be nice if the flaw was found before completing another prototype.

We have Patent Pending status on this motor. The patent attorney says that the pending status protects our design. Our patent includes a Patent Cooperation Treaty that protects us internationally for 30 months. By then we could have patents across the globe.

Thanks for your input. We are about to be out of town for a little over a week and won't be able to post any animations. We will still be able to post to the forum but the posts probably won't come as often as before.

We contacted everyone that was at our shop when we fired up the prototype to see if anyone had recorded it. It turns out that one person recorded it: my uncle.

It was filmed on a phone so the quality is pretty bad. In the video we were limiting the engine to 3000 RPM to break-in the seals. My dad squirted oil into the carburetor a couple of times during the video to keep everything lubed. As we've mentioned before, the seals ended up digging into the aluminum quicker than expected and the assembly seized. The motor locked up a few minutes after my uncle's phone ran out of space to store the video.

We are planning to start machining parts soon. We will also be showing a live feed of the parts being machined. I will post more information about the live feed as we get closer to machining.

oh nice noise

Bumble bee on steroids

I'm not finding the website

Here's an active link for the video

A link to the discussion on engineers edge

the seals certainly are going to be critical

on 2stroke motorcycles it is common the harden the aluminum cylinder bores

the wear characteristics are impressive,

since there is no sleeve, heat transfer is much improved

Here's a suggestion, have a look at biodiesel for the lubrication,

I'm sure that you're already using 2stroke premix oil

Sorry for posting links improperly. On my computer using Chrome the bar above the box I'm typing in currently does not appear. This means the hyperlink button is missing. However, on my dad's computer (the one I am currently on) using Firefox the bar appears so that I can do this: Doyle Rotary

I've been copying and pasting between the forums so you might not find any new information at engineer's edge.

We want to copy Wankel's chrome plated surfaces because we can be certain that the seals won't dig into the surface. Hardened aluminum surfaces might be an alternative in the future after we get some data from this prototype.

We will be using the oil metering pump from the Wankel engine. It will spray oil on the seals exactly as it does in the their engine. This means no oil will need to be added to the fuel. Using the metering pump will be better than adding oil to the fuel because less oil will be used because it will be applied directly where it needs to be.

Welcome to CR4, The links & picture thing is a pain on anything except IE or FF

thanks for the site link

My questions/observations about the oil was not to suggest mixing oil with the fuel, But pondering what kind of oil you are using to lube the seals?

Here's some more on Nikasil plating, instead of plating, actually changes the surface & Can't chip or flake around the ports or combustion chamber.

Ed probably has some useful comments about the thermodynamic stuff.

I certainly don't see any reason not to water [or oil] jacket the combustion chamber to maintain optimum conditions

continuing to state the obvious the goal being to have the expansion not to upset the sealing surfaces, things are gonna move, you just need them to move the way you want

I meant a video of an actual motor, not a simulation.....

After 20 odd years of developement, I would have thought that at least one would have been built and got to run.....just a thought!! Maybe I am off key in this area.....who knows?

I'm sorry, but from what I understand the performance of the engine would be quite poor, due to the small (cross-sectional-area) size & length of the gas paths - simply the more air into the cylinder, the more fuel can be burnt etc etc