A work of pure genius! - Brilliant "Revetec" Engine

[revetec]

Now we are getting people to think a bit more about the dynamics of the design...There are things I have not disclosed, but with a great deal of thought out there, and if everyone thinks hard about the dynamics of this engine, there will be some great ground breaking theories and calculations coming out. This will be very interesting for me personally, to see if other parties come out with data that is similar to mine. Cheers

[Kozy]

I will admit the rendering is not perfect, I agree the piston positions are not perfect there. The CAD model is not being designed as a production model, more to help mke understand the workings of the engine.

Hightower you are not using indicated torque and power equations. Those equations take into account things like fuel conversion efficiency, volumetric efficiency, heating value of fuel and density of air.

[hightower99]

Originally Posted by Kozy

Hightower you are not using indicated torque and power equations. Those equations take into account things like fuel conversion efficiency, volumetric efficiency, heating value of fuel and density of air.

I am not sure what you mean by "Indicated" torque and power equations?

Care to give an example?

The equation I just posted takes everything you just mentioned into account as it uses measured power and torque.

[Kozy]

Measured, as in what is taken from an engine dyno. Indicated is just that, an indicated figure, minus friction losses, used in engine design. You don't think engine designers rely purely on measured figures in design?

[hightower99]

Originally Posted by Kozy

Measured, as in what is taken from an engine dyno. Indicated is just that, an indicated figure, minus friction losses, used in engine design. You don't think engine designers rely purely on measured figures in design?

Of course engineers don't rely solely on measured figures (they have to set alot during design stage).

Basically what I want to know is exactly what formulas you believe don't apply to a revetec style engine and why?

The simple ones I can think of apply normally, of course the geometry of the crank system has changed but that doesn't mean the basic principle doesn't apply.

[revetec]

How about deflected side thrusts and/or peak transfer regardless of position of peak pressure, higher transfer of force at lower RPMs and lower side thrust losses. You need to plot an average engine's combustion pressure plot in 3D (RPM and Load) then match it to torque levers achieved at those degree points.

The dynamics are quite different from a conventional engine. There is enough info on the web to get a rough idea of what is happening.

If you are really interested, perform a full analysis and tell everyone your results. After which I know you will believe in the project, but I want you to say it in your own words from your own calculations and understanding of the results.

I know with your Revetec variant prototype you want to build, that you will arrive at all this before you build your engine.

[revetec]

Kozy: BTW...was the email helpful?

[Kozy]

I can't post them in here simply, it's all handwritten stuff in my notes and stuff using equation editor addins. Look it up on google, there is a PDF masters thesis' about that goes into great detail about it at the top of the page.

I am not going to argue my case absolutely as in all honesty I do not know enough to do so at present.

[Kozy]

Yes very much so, I had never thought of looking at it that way. Many thanks. I will be emailing you again in the near future with some other questions, I'll try not to try to much into interllectual property though!

[revetec]

When you do understand and calculate it all accurately, there may be a job for you as I'm always snowed under when I'm calculating and designing.

[revetec]

The trilobe design process will keep you busy for a while.... It takes me about 2 full days on a high resolution trilobe with 0.0008mm face accuracy and plot points every 1/3 of a degree!

[Kozy]

Originally Posted by revetec

When you do understand and calculate it all accurately, there may be a job for you as I'm always snowed under when I'm calculating and designing.

I'm very interested, I'll give it a go tomorrow and see how it goes!

[revetec]

Just remember that your first decision is the acceleration rate of the piston which determines operational speed of the engine and the length of the conrod you need to factor into the calculation. Do this first! For your model just calculate it every 3 degrees and it will look fine.

[hightower99]

Are you talking about this:

Calculating and Comparing the Output Power and the Indicated Power of a Simple IC Engine

I understand what you mean now. You are talking about the power generated by combustion before mechanical losses are subtracted (revealing mechanical efficiency)

Funny that this experiment shows mechanical efficiency between roughly 82% and 94% for a conventional engine... alittle more than what revetec would have you believe...

[revetec]

Originally Posted by hightower99

Funny that this experiment shows mechanical efficiency between roughly 82% and 94% for a conventional engine... alittle more than what revetec would have you believe...

As a hint: At 30degrees ATDC when the peak pressure is at its highest (Lower RPM) the mechanical transfer of a crank is not good (a great % of the force is directed to the crank main journal) creating mechanical losses. Draw a simple model and see for yourself. The quoted figures you posted are at a crank's peak when the conrod is 90deg to the crank. This is about 60-70deg ATDC and at which the peak pressure occurs between 3,500rpm and 4,500rpm, hence peak torque normally.

Remember...We produce 90% of peak torque at only 1,300rpm. A direct result of applying more leverage at an earlier degree ATDC.

It actually makes me laugh at crankshaft efficiencies posted all over the web. Everyone always quotes the peak figure and everyone reading them assumes that this figure is constant throughout a stroke. It Isn't! If it was... on a dyno graph it would be close to a torque line, not a curve and little need for much ignition advance variance with load changes.