Doyle Rotary Engine P/V Graph

First off, I checked out your website and would like to say I like your theory and design.

Second, I would like to know if you have toyed with Natural Gas as a fuel.

Third, If you have a working prototype, can you use pressure tests similar to compression tests on a diesel where you can guage relative compression using resistance to fuel being pushed through the injectors? (basically measure back pressure against the injectors) Or am I thinking wrong? please let me know.

I was thinking that actual numbers not numbers computed from specs may provide more realistic numbers.

Thanks and yes natural gas is a possible fuel to use although my target fuel is gasoline and my target market is passenger vehicles.

I have had limited success in my many prototypes, usually by the time I have one near completion I have found an improvement that obsoletes the previous design.

I have only built one prototype of my newest design and it seized due to improper material usage.

All of the pictures on my website are of an older prototype and so is the patent, I will be updating them soon.

The 3d models on the parts page are of the new prototype.

I have changed many things that should fix the seizing problem but it will still be several more prototypes before I will have usable numbers.

I just realized that I have not put pics of my new model on my site yet so I added a view of the engine without one of its end covers so you can see inside of it.

The outer housing, cylinders, rods and pistons all rotate around a stationary crankshaft.

First of all, i appreciate for your effort in this direction. To your question to calculate the pressure Vs Volume, this can be done for compression chamber (colder / intake chamber) as this is governed by simple thermodynamic adiabatic equations. Use P*(V^gamma)= constant. i e P1(V1^gamma) = P2(V2^gamma) Take the initial conditions for solving the above equations i e P1 = atm pressure in pascals, V1= volume of cylinder at BDC. You can take the compression ratio (8 - 10 etc). So you will calculate the V2. then apply the above formula to find P2. thus you can find parameters at any moment of stroke. To find the P V graph for second chamber ie combustion chamber, you need to find the rate of heat release or combustion rate. That is not some thing i recommend. the more simpler thing to do, if you have built the functional prototype, just measure pressure (volume you know already). To streamline the design process, better all things have to be decided on the paper first. When everything is proper and no mistakes, you may go for real prototype. That saves your precious time and effort.

The problem I have with doing calculations on this engine is that as the assembly turns it passes across ports to allow for timing of cycles.

At any given time the combustion chamber will be open two two or three power and exhaust pistons and during that time the intake and compression piston will add another shot of fresh air.

The fuel is then added directly into the combustion chamber and ignited near TDC.

The timing of the ports greatly affect the piston port overlap. I have a spread sheet that shows the position of each piston's distance from TDC at half degree intervals. It also shows where each port starts and stops. If you need it I can shoot it to you in an e-mail