How Does Thrust to Weight Ratio Impact Engine Efficiency?

[chhitiz]

opinions?View attachment e.pdf

 

[Cyrus]

All I see is a cartoon drawing.

 

[chhitiz]

perhaps that's all you are capable of.

 

[grey]

wow...the idea seems really cool (at least to me)
but, i think cyrus has a point here...its just a drawing (and obviously a vague explanation). you might have done calculations for power, efficiencies, and a whole lot of stuff (that i often don't understand)

 

[0xDEADBEEF]

I thing you want or should produce some rotating pressure wave. That is nice, but ther are some issues:
1) is it more effective than a turbine?
2) The pistons will have to move independently. How do you get the torque out of the tube? If you do it mechanically, how do you keep the tube sealed?
3) How to you get the fuel in and the exhaust out of the tube?

 

[chhitiz]

it's a toroidal ic engine. people have speculated about making one because, at least in theory they seem to avoid the "reciprocating effect" of normal ic engines, or get higher power to weight ratios. most of previous designs have been unsuccessful due to problems of sealing, or power transmission method, etc,etc. check trochilic, myt, circular, rotoblock and roundengine on google. and thisView attachment Document1.pdf i think i have with this design, better sealing and better way to transmit power to crankshaft.
in a way, i am trying to remove flaws in previous ones. please point out to me whatever you see is not right.
@grey, yes cyrus has a point. i must admit that all i have is a design with it's drawing. i want to find out the effeciency, but don't know if that could do that without making an actual prototype. if i knew of some software to simulate it(i'm pretty sure ansis or pro-e won't do). somebody help.
@deadbeef
1) don't know
2)see fig. 8,9,10
3)see the fig.3. now the metal strips are such that the intake manifold and outer circumference are completely sealed, except for a small length of the outer circumference, which provides inlet. the pistons change their positions such that every section where there has been a combustion, there is an inlet formed. the outlet is formed by expanding polymer strip.

 

[Cyrus]

perhaps that's all you are capable of.

Get serious if you want me to take you seriously. All you have are some drawings that are poorly labeled, at best.

 

[berkeman]

Cyrus and OP -- mellow out. The idea is interesting, and a better explanation would be good. Let's stay focused on the idea, and stay away from any personal attacks.

 

[Capt. Obvious]

interesting idea

 

[chhitiz]

can somebody tell me how to calculate efficiency?

 

[Mech_Engineer]

can somebody tell me how to calculate efficiency?

The amount of modeling and calculation involved in trying to determine the efficiency of a conceptual engine is nearly insurmountable. Before you go any farther you should realize that there are people out there that have already tried to invent what you're looking at (and I'm sure they've filed patents as well).

If you want to look any farther, you need to first do a patent search to see what toroidal concepts are already out there.

 

[chhitiz]

yes I've checked there are no toroidal engines which resemble my design. could anybody tell me what to do next?

 

[Mech_Engineer]

yes I've checked there are no toroidal engines which resemble my design. could anybody tell me what to do next?

I know for a fact that's isn't true, because I've seen a design nearly exactly like yours in past years. Perhaps you haven't looked hard enough (or at all)...

http://www.dself.dsl.pipex.com/MUSEUM/POWER/unusualICeng/toroidalIC/toroidalIC.htm

 

[chhitiz]

dood that's an oscillating piston engine my pistons don't oscillate they move circularly in same direction(one at a time) causing compressions and ignitions. I've seen bsa or tschudi engine countless times before

 

[FredGarvin]

I suggest this thread be closed for failure to utilize "dude" properly.

I see no discussion of the heat transfer issues you will certainly have, especially with a metallic strip providing combustion sealing right next to a polymer strip. Also, you show spark plugs. How do you get the wires to the spark plugs? What controls the timing? The friction and heat loss alone will guarantee the efficiency (if it actually did run) to be pretty low IMO. It definitely will be a low speed engine.

 

[chhitiz]

the metal strips are not just next to the polymer strip, i don't see why heat transfer should be an issue. the wires to the spark plugs would be through the piston projections you see. i control timing through a disk attached to the central shaft which keeps track of which piston needs to be fired. yes, the friction will be more, but we still need to see how much it affects efficiency. i don't know why you expect the heat loss to be more than any other engine, or it to be a low speed engine

 

[FredGarvin]

So you're saying that the surrounding structure and air inside an IC engine is not going to get hot? Is that what you are saying?

If the wires go through like that you will need some form of slip ring or brushes. Are those in there? I didn't see anything like that.

 

[chhitiz]

yes it will get hot, but why should the heat loss be any different from a normal ic engine? yes there are slip rings and i didn't include them in the diagram. the diagram only outlines the basic structure.

 

[Brian_C]

Am I missing something? How do you keep the other pistons from moving during the expansion/compression cycles? According to your diagram, only one piston will move at a time. That's impossible unless the other pistons are held in place, and released at precisely the right time. The pistons also have to be held in place after they come to a stop.

 

[Redbelly98]

That's a good point. Each explosion should push with an equal force in both directions. How is torque generated in the preferred direction?

Maybe it's clear to people with mechanical engineering training; I'm a former experimental physicist, lurking (until now) in this thread.

 

[chhitiz]

there is a locking mechanism for that. a disk pushes pins in casing in such a way that the stationary piston gets locked. i only put up those parts that i thought could have faults.


can somebody please tell me how i could calculate efficiency?

 

[gmax137]

Well, I admit I don't really understand how this works. But if I understand what you just said, the piston moves along the toroidal path, comes to a stop, then moves again? If that's the case, then what's really different between that and a 'regular' piston/crank device? I mean, in terms of the 'reciprocating effect' you mentioned above, seems like you're still accelerating and decelerating the piston?

 

[chhitiz]

that's the point. in a reciprocating engine, the flywheel decelerates the piston(for storing energy) and then pushes it. whereas, in this design, the piston stops all by itself, not due to deceleration by the flywheel. so fuel energy is converted to rotary motion in a more direct way.

 

[Mech_Engineer]

Your pictures are nearly impossible to decipher. They may be obvious to you, but it seems to me that no one is getting it. You're going to need to make some sort of animation if you want more useful feedback.

 

[chhitiz]

i know. i have tried explaining to my friends and they can only understand when i am explaining it to them every basic detail in person. i don't know animation, but could try getting a flash file or something. but, it would help, if you could assume that what i have designed is possible to build and seal, and then guide me as to how to calculate, at least in theory the efficiency, or simulate this design on some software. as far as i know, ansis or pro-e won't do.

 

[gmax137]

in this design, the piston stops all by itself ...

Now I'm really lost. I don't see how that is even possible.

 

[Mech_Engineer]

but, it would help, if you could assume that what i have designed is possible to build and seal, and then guide me as to how to calculate, at least in theory the efficiency, or simulate this design on some software. as far as i know, ansis or pro-e won't do.

Assuming it is possible to build is a big leap, but even if we make that leap there really is no easy way to calculate the efficiency of the engine. Just making a guess based on engines with similar compression ratios is your best bet IMO, and that will likely be around 15-20%.

It's useless to calculate the efficiency of the engine anyway since I'm not seeing some critical stuff like how the pistons are attached to a crankshaft, or where your intake/exhaust valves are.

 

[chhitiz]

Just making a guess based on engines with similar compression ratios is your best bet IMO, and that will likely be around 15-20%.

what are the engines with similar compression ratios? any of them toroidal?
can we simply guess the efficiency based on c.r.? is there a way to calculate the precise efficiency of a completely new design?

 

[grey]

i think for a 'normal' IC engine, the starting point for the efficiency would b the Otto cycle. lots of assumptions there...i think it ll give a very rough guess in terms of the proposed compression ratio and the temperatures you would expect. don't know if it applies to that, but you might make some of your own assumptions...and then work from there...dunno

 

[Bystander]

Gas turbine engineering solved all the sealing (clearances and rotor/stator designs), coupling of "pistons (buckets)" to output shaft, and ignition and combustion problems a long time ago with many fewer parts. Efficiencies are in the 50-60% range for large installations.

 

[blade86]

i think you have confused mechanical design with an idea. there are no calculations or measurements provided. Perhaps if you can draft the pictures out or use CAD and provide some of the formulas etc , then people can better assess how workable this project may be.

 

[chhitiz]

@ grey it is not otto cycle.more like a three stroke cycle.
@ bystander yes, but we can't use gas turbines in automobiles. for one thing, they operate at very high temperatures and pressures
@ blade well, I'm trying to, but could people anyways suggest a way to calculate efficiency or something

 

[Unit91Actual]

It looks like you made that in Abaqus (?). If so, did you run an FE simulation to see what types of stresses are in the engine? One of the biggest concerns in efficiency is thrust to weight ratio (T/W). If you want to take this to the next step, I recommend seeing what your stresses are like, and determining if you have too much / too little material. Factors of safety are also important.

 

[atthepointe]

I didn't see anything.

 

[gmax137]

... guide me as to how to calculate, at least in theory the efficiency ...

... can we simply guess the efficiency based on c.r.? is there a way to calculate the precise efficiency of a completely new design?

... could people anyways suggest a way to calculate efficiency or something ...

What exactly do you mean by 'efficiency'? Can you write down what you mean in words, and then take a stab and quantifying it? Why do you think calculating it is any different then the 'efficiency' calculations described in the automotive engineering textbooks?

 

[chhitiz]

It looks like you made that in Abaqus (?). If so, did you run an FE simulation to see what types of stresses are in the engine? One of the biggest concerns in efficiency is thrust to weight ratio (T/W). If you want to take this to the next step, I recommend seeing what your stresses are like, and determining if you have too much / too little material. Factors of safety are also important.

it was made in catia. and as far as i know, there is no way of getting the stresses in it.

What exactly do you mean by 'efficiency'? Can you write down what you mean in words, and then take a stab and quantifying it? Why do you think calculating it is any different then the 'efficiency' calculations described in the automotive engineering textbooks?

efficiency is how much of the chemical energy of the fuel is actually converted into useful work. and calculating it is different because this design will have a totally different thermodynamic cycle