engine without crancshaft

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Serguei
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engine without crancshaft

Postby Serguei » Sun Jul 03, 2016 3:47 pm

https://www.youtube.com/watch?v=4uEXPAZlZYg

Current engines of internal combustion are constructed under the classical circuit, namely, the cylinder, the piston, a rod, a cranked shaft. It should be noted, that in traditional engines a number of well-known deficiencies takes place, namely:
1. An inefficient combination of pressure upon the piston and tangential force on the crankshaft.
Here it should be noted that during the maximal increasing of pressure and combustion of 80-90 % of the mixture, the crankshaft turns by angle φ from 0 ° up to 90 °. Thus the transfer ratio of tangential force to force working on the piston changes from the value of zero up to the value of one.
Thus, during the turn of a cranked shaft from 0 up to 90 degrees, the combination of two phenomena is observed:
а) Change of pressure from maximal up to minimal;
b) Change of a transfer ratio of tangential force to force working on the piston from the value of zero up to the value of one.
2. The largest losses occur when friction arises in the piston-sleeve combination (45-55% of all losses due to friction in the engine). A primary reason for these losses is the sign-variable lateral force, arising in piston-sleeve combination that changes its direction during the turn of a cranked shaft up to 180 degrees. The sign-variable lateral force directly depends on the size of lever of crankshaft. The larger the lever of crankshaft, the greater the sign-variable lateral force. On the one hand the size of lever of crankshaft defines the meaning of torque, but on other hand the size of lever of crankshaft defines meaning of the sign-variable lateral force. To eliminate the consequences of sideways forces are used the different crossheads but they have enough complicated design and system for lubrication.
Now it is possible to formulate a task. The force, which affecting the power shaft must depend on only pressure above the piston during the entire movement of the piston. Design of engine must not cause reactions in piston-sleeve combination.
The presented 4 stroke engine consists of four cylinders, where under pistons fluid, the hydraulic control valve and the hydraulic motor. The cylinders are connected in pairs by rods.
A typical feature of the suggested engine is that the shoulder of tangential force on the power shaft on all way of moving of the piston remains constant and defined by the size of impeller. Change of magnitude of the torque in this case is defined only by one factor, namely, change of pressure in the cylinder in the process of moving of the piston. As seen in the presented engine here is absence sign-variable lateral force that causes 40-45 % of all losses in engine. The length of the moving of the piston is not related with the sizes of the power shaft.
For comparison of both models have been done estimation of torques, which are presented on the diagrams.

The diagrams show the change in torques in the presented and existing designs. (I apologize; I did not have enough information for calculation diagrams for RT-flex96C. Therefore I used diagrams of other smaller engine). Statistical sets of variations of torques in the presented design and in the design with the cranked shaft during the rotation of the power shafts from 0 to 180 degrees are characterized by average arithmetic values. Comparison shows that the average arithmetic meaning of torques in presented model in 1.8 times greater than average arithmetic meaning of torques in existing one. It should be noted that absence of relationship between the length of the moving of piston and the sizes of the power shaft allows significantly (reasonably) increase diameter of impeller of the hydraulic motor and hence the shoulder of torque. It means that in the presented model for achievement the required power will not be required the increased number of rotation of the power shaft. There are several obvious benefits. First, fewer rotations means the less heating of engine. Second, fewer rotation means reducing of the thermal intensity, wear resistance and increasing of reliability.
Using information from “The Largest And Most Powerful Diesel Engine in The World” (http://www.amusingplanet.com/2013/03/th ... iesel.html)it it is possible to estimate the benefits for RT-flex96C. The presented design will allow increasing of the torque at least in 1.8 times and it will be equal 7,603,850 x1.8 =13686930 newton metres. At the same time it is possible to install the hydro motor in which vanes will be more than 1.25 m (lever of crankshaft) in 2 -3 or more times and increase torque and power in the same size.
The presented 4 stroke engine could be transformed in 2 stroke engine, if it need. In my opinion, cost of production of new engine will be significantly lower than cost of existing one.

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Merlyn
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Re: engine without crancshaft

Postby Merlyn » Mon Jul 04, 2016 11:45 pm

Interesting take on suck, bang ,blow, exhaust.
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

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Big Pete
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Re: engine without crancshaft

Postby Big Pete » Thu Jul 07, 2016 4:53 am

I wish I understand the original post better.
However I can see a huge disadvantage, there is a large mass of Hydraulic fluid that has to be accelerated and decelerated taking considerable power and also there will be large frictional losses in the hydraulic circuit. Which means the hydraulic fluid will have to pass through coolers and there will have to be cooling water pumps etc.

How about resurrecting the "Free Piston Gasifier" as an alternative?

BP
It is always better to ask a stupid question than to do a stupid thing.

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Merlyn
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Re: engine without crancshaft

Postby Merlyn » Thu Jul 07, 2016 7:53 am

I am trying to work out how to convert a four stroke to a two stroke without swallowing a workshop manual.
Struggling at the mo.
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

Serguei
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Re: engine without crancshaft

Postby Serguei » Tue Jul 12, 2016 7:44 pm

Dear Big Pete and Merlyn,
Thank you so much for your attention to article . Right now I am on vacation in the Texas. I will be at home July 23 and of course I will respond to your questions.
Best regards
Serguei

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Merlyn
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Re: engine without crancshaft

Postby Merlyn » Wed Jul 13, 2016 4:21 am

Bring your milling machine and cutters, don't forget a decent file to radius out the new ports.
What do you reckon re the journal radius's?
Lot different on two stroke v fours
Might need a crank grinder too?
Enjoy your hols
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

Serguei
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Re: engine without crancshaft

Postby Serguei » Wed Jul 27, 2016 11:43 am

Dear Merlyn,
I appreciate your excellent sarcasm and I glad I that gave you food for brain exercises. :-) Actually it is my mistake. I did not express my thought correctly. I wanted to say that in the presented engine might be used design of two-stroke cylinders. In any case, I thankful for your participation in discussion.
Best regards
Serguei
If we exchange by apples so each us will have one apple, but if we exchange by ideas so each of us will have two ideas.

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Merlyn
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Re: engine without crancshaft

Postby Merlyn » Wed Jul 27, 2016 11:28 pm

Apologies if you thought it was any of it was sarcasm, excellent or not because it was not intended to be at all.
Of course I knew you would not be taking your crank grinder, milling machine etc with you on holiday as they are normally three phase and as such your hotel power supply would not run them.
You'll have to give me a bit more time though re the two apples v two ideas theory, stab in the dark, Confucius?
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

Serguei
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Re: engine without crancshaft

Postby Serguei » Mon Aug 01, 2016 9:19 am

Big Pete wrote:I wish I understand the original post better.
However I can see a huge disadvantage, there is a large mass of Hydraulic fluid that has to be accelerated and decelerated taking considerable power and also there will be large frictional losses in the hydraulic circuit. Which means the hydraulic fluid will have to pass through coolers and there will have to be cooling water pumps etc.

How about resurrecting the "Free Piston Gasifier" as an alternative?

BP

For Big Pete
’However I can see a huge disadvantage…..” You are absolutely right but I would like to divide your consideration in two parts. First I should note that these huge disadvantages you can observe in the traditional engines of internal combustion. Instead mass of hydraulic fluid there are a mass of parts of crankshaft and rod. Second, according to the large frictional losses. Actually, these losses are exist as well as like in the traditional engines. We should consider meanings and disadvantages of them. In general you are right according frictional losses. I considered this idea for engines with low revolutions like for big ships, assuming temperature will not high due this. And I think you gave me good advice about “Free Piston Gasifier" as an alternative”. Soon I will finish my list to do in my home and will try to create gasifier using presented here engine.
If we exchange by apples so each of us will have one apple, but if we exchange by ideas so each of us will have two ideas.
Serguei

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Re: engine without crancshaft

Postby Hypatia » Mon Aug 01, 2016 11:27 am

Interesting, Serguei. Have you seen the CHB Evo "1 stroke" toroidal engine?

https://m.youtube.com/watch?v=UvKnaBgX2YA

What do you think about the tangential forces on that crankshaft?

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Big Pete
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Re: engine without crancshaft

Postby Big Pete » Wed Aug 03, 2016 7:02 am

Hi Sergui,
Just read your last post. I see that you are comparing energy losses due to accelerating/ decelerating the hydraulic oil with those of the crankshaft and connecting rods.
However the crankshaft is usually rotating at constant velocity and therefore there is no inertia to overcome in turning the crankshaft. There is of course, inertia to overcome in the piston, but if you are driving one side of the piston by the exploding fuel and using the other side of the piston to pump oil then the forces in the piston would be uniformly spread, rather than acting at a concentrated point (the attachment to the Piston Rod / connecting rod) therefore the entire piston could be redesigned to be much weaker & lighter, greatly reducing its inertia. Much of the weight of the piston is due to it having to concentrate the distributed force of the gas pressure across the entire surface of the piston crown in order to use it to drive the piston / connecting rod.

I would expect that the volume of oil in the cylinder would be much heavier than the weight of a piston and would therefore have greater inertia.
With regard to generation of heat in the oil this would largely depend on the viscous drag in the system and the amount of power being transmitted I do not see how the engine speed would affect it. If you are transmitting the power output of an RTA through an Hydraulic system you will need lots and lots of cooling.

Nor do I see any advantage in running the engine more slowly that it is designed to be run. The engine components are all optimised for running at full power i.e. maximum torque and RPM, running the engine at reduced torque and or RPM will led to poor combustion and carbon deposits building up in the Gas side. The hydraulic system should be optimised for the engine running at its rated power. De rating the engine would greatly reduce the power to weight ratio of the plant and its thermal efficiency.

If you ever get one of your engines running we would all love to see it.

BP
It is always better to ask a stupid question than to do a stupid thing.

Serguei
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Re: engine without crancshaft

Postby Serguei » Mon Aug 08, 2016 1:20 pm

Hi Big Pete,
Thank you for your detailed analysis and conclusions. They have been given me good meal for brain exercises.
“However the crankshaft is usually rotating at constant velocity….” I think that constant velocity in this case is quasi-constant and velocity of rotation described by the schedule of sinus. Of course, flywheel significantly improves situation but does not do it absolutely perfectly. It means that we should take into consideration the irregularity of rotation and accordingly acceleration and desceleration.l
“With regard to generation of heat….” I should say that in this case my explanation is not perfect. I did not attract your attention to fact that the presented engine was creating for the big ships. Engine of these ships has 80-120 rpm (http://www.amusingplanet.com/2013/03/th ... iesel.html). I agree with you that “heat in the oil this would largely depend on the viscous drag in the system…” But we should agree that low rpm will less affect thermal condition of engine. In this case rpm 80-120 is optimal for this engine and keeping the optimized torque and power.
Thank you for participation in discussion
Sincerely yours
Serguei

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Big Pete
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Re: engine without crancshaft

Postby Big Pete » Tue Aug 09, 2016 5:51 am

Hi Sergui,
The rotational speed of the crankshaft is virtually constant and the larger the number of cylinders the nearer to constant it will be, and as you say, having a flywheel helps smooth the small acceleration and deceleration of the rotational speed.
The Hydraulic oil you are pumping has to be accelerated from completely stopped to maximum speed for every stroke of every pump, that is a large amount of inertia to overcome. The momentum of all the oil moving in the pump cylinders and around the hydraulic system will, to some extent act as a flywheel, because it will always tend to continue moving at a constant velocity, and would help make the engine run even more smoothly.

I have sailed on many ships, for many years, with 900 m.m. bore engines running at slow RPM, Sulzer RD, Sulzer RND, Sulzer RTA, MAN, B&W etc. as you describe, but they do not require any less cooling of the Cooling water and Lubricating oil when compared to an engine of similar power output running at higher RPM. Because the heat generated is smaller in proportion to the mass of the engine and the fluids in it, the temperature rises more slowly, but just as much waste heat is generated in any given time, and has to be transferred to the cooling medium.

As I said previously I would expect the size of the cooling plant for the Hydraulic system to be proportional to the power transmitted hydraulically, it has nothing to do with the speed of the engine.

BP.
It is always better to ask a stupid question than to do a stupid thing.


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