Engine of internal combustion without crankshaft

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Serguei
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Engine of internal combustion without crankshaft

Postby Serguei » Sat Nov 21, 2015 1:26 pm

https://www.youtube.com/watch?v=A64DYtsnV9w
Engine of internal combustion without crankshaft
Modern scales of production of piston engines of internal combustion have resulted in their significant impact on environment. Emissions from engines of internal combustion essentially increase concentration of the chemical substances in the air, water, soil and become dangerous to human life. The problem now has no solution and at the same time is characterized by the steady tendency of increase.
One of the basic ways to decrease harmful emissions of by-product gases is to improve fuel efficiency of engines. The size of harmful emissions is determined by perfection of a design of internal combustion engine. The higher the efficiency coefficient of the engine is the better its fuel efficiency, the higher its ecological qualities.
It is necessary to note, that huge work on perfection of engines now is being done and significant results in decrease in emissions in an environment are being achieved.
At the same time, the tendency of increasing impact on environment remains, and prompts the search for new solutions to the problem.
Current engines of internal combustion are constructed under the classical circuit, namely, the cylinder, the piston, a rod, a crankshaft. It is necessary to note, 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 crankshaft.
Here it is necessary to note two aspects:
а) process of combustion of a mixture begins before the piston arrives at “top dead point” and it allows to assume, that the movement of the piston to the ”top dead point” is counteracted by total pressure: the sum of the degree of compression, and increasing pressure of the inflamed mixture, and that results in loss of power.
b) during the maximal increase 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 crankshaft 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.
3. Engine of the internal combustion uses in average only 75 % of fuel and 25 % goes in the exhaust pipe and muffler. Namely this part of fuel is burning in the catalyst. But catalyst is very expensive device and it requires the substantial part of powerful of engine for pumping fuel through a dense net of surfaces of catalyst. It is known that for a full and complete combustion of the fuel vapor desirable high temperature and high pressure. When the piston is at top dead point, the compressed mixture is ignited. But immediately when the piston passed the top dead point, it starts to move down with the significant increasing of space above the piston. With the spread of the flame front of the mixture in the combustion chamber the first portions of mixture will burnt at high temperature and high pressure. But the latest portion of hot mixture burns under condition of the sharply declining of pressure and falling of temperature. For this reason, part of the mixture does not have time to burn or not burn fully.
Now it is possible to formulate a task.
1. The force which affecting the power shaft must depend on only pressure during the entire movement of the piston.
2. The process of burning must start in the closed combustion chamber without moving of the piston.
3. Design of engine must not cause reactions in piston-sleeve combination.
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.
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.
On the diagram shows the change in moments in the suggested and existing designs. Statistical sets of variations of moments in the suggested design and in the design with the crankshaft during the turning of power shafts from 0 to 180 degrees are characterized by average arithmetic values. An average arithmetic value of the moment in the suggested design is 1.83 times greater than average arithmetic value of the moment in an existing design.
Work is determined by the moment and a turn angle
Ç = M · φ, (1)
Where M - the moment;
φ – a turn angle of a shaft.
Since the average moment on the power shaft in the suggested design is 1.83 times greater than the average moment in traditional engines, it is possible to consider that power also 1.83 times greater at the same level of fuel consumption. Hence, it will allow to reduce the emission of by-product gases in the same degree.
In the suggested engine design the operating conditions of piston-sleeve combination are essentially improved, due to exclusion of sign-variable lateral force that allows to lower the cost of manufacturing, increase engine resource, increase efficiency coefficient.
In the suggested design the mixture is ignited at the “top dead point". The piston remains motionless during rotation of the power shaft by 90 degrees. During this time pressure above piston sharply increases. When the piston begins to move the increased pressure affects the power shaft and hence the capacity also is increased. The motionless of the piston allows to burn more fuel mixture and hence to decrease emission of engine.
The suggested solution increases of capacity of the engine due to the factors considered above, not resorting to increase in number of revolutions of the engine that results in increase in thermal intensity and by-product gases gas emission, reduction in reliability and wear resistance.
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Merlyn
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Re: Engine of internal combustion without crankshaft

Postby Merlyn » Mon Nov 23, 2015 4:16 am

What happened to the Wankel engine invention? No crank here.
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Big Pete
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Re: Engine of internal combustion without crankshaft

Postby Big Pete » Mon Nov 23, 2015 11:39 am

The Graphics are excellent and it certainly looks to be a very compact engine.

Not sure about the Physics/ Applied Thermodynamics of your assertions:

The work done on the piston, by the gas pressure is = piston area x mean pressure x length of stroke.
That determines the amount of power transferred to the crankshaft.

You can not get more power out of the crankshaft than you put in the piston!

Fuel is injected before TDC partly because of the ignition delay, ignition of the fuel is not instantaneous, and by starting combustion just before TDC I always understood that this reduced the shock loading on the combustion chamber and allowed the combustion to take place at the most efficient pointy, TDC i.e. at constant volume, combustion after this point is inherently less efficient as the gas does not fully expand before exhaust and therefore potential energy is wasted.

To me it appears that there is still a tangential force on the piston because the crank throw is rotating and does not remain lined up with the centre of the piston.

If the angle of the connecting rod is changed to produce more torque at the crankshaft, then greater pressure will be required to move the piston.

The principle increase in efficiency would appear to be due to maintaining "constant volume" long enough for all the fuel to be burnt, the reason this is not done in conventional engines is because all the components have to be much heavier to support the higher pressures generated and would also have to be ceramic coated to resist the high temperatures produced.
The reason traditional diesel engines burn fuel at both Constant Volume and Constant pressure is because although burning fuel at Constant Volume is more efficient, in terms of the Carnot cycle, it cannot generate much power. Burning fuel at Constant pressure as the gas expands during the power stroke maintains the temperature and pressures at the maximum permitted by the material design and therefore enables the engine to produce worthwhile power outputs in relationship to its weight and cost.

I think your logic in suggesting that such an engine would produce 1.83 times as much power as a conventional engine and have an efficiency of over 73%, compared to the 40% efficiency of modern Marine Diesels, is flawed.

BP
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Merlyn
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Re: Engine of internal combustion without crankshaft

Postby Merlyn » Fri Dec 04, 2015 5:58 am

Not convinced that this non duplex chain drive is entirely Gorviendo valve oscillation free here? Anyone?
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JollyJack
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Re: Engine of internal combustion without crankshaft

Postby JollyJack » Sun Dec 06, 2015 9:02 pm

Pescara Muntz had a free piston engine, opposed pistons with air cushioning linked by pivoting levers attached to the pistons.

https://books.google.ca/books?id=kCKMy7 ... tz&f=false
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Big Pete
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Re: Engine of internal combustion without crankshaft

Postby Big Pete » Mon Dec 07, 2015 1:41 am

I remember studying a "Free Piston Gasifier" Engine as a Cadet. It was a conventional engine with a crankshaft but no power output from the engine!
Instead the exhaust gas was used to drive a power turbine, which did all the work, it sounded pointlessly complicated to me at the time and still does!!

I just followed the link above again but now it is showing a different engine so I am a bit confused.
The first one I looked at had a "Crankshaft" but no connecting rods, instead the throws of the crank acted as gudgeon pins and, if I remember correctly, ran in eccentric bushes in the piston to allow for the changes in alignment during the stroke. So in effect these bushes were performing the role of very short connecting rods, but this idea could only work with an engine with a large bore and short stroke.

BP
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JollyJack
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Re: Engine of internal combustion without crankshaft

Postby JollyJack » Tue Dec 15, 2015 6:42 am

Starting the Pescara-Muntz compressor was a bit of an adventure. The outer crown of one of the pistons was within an enclosed cylinder and the piston acted as an air spring. The other piston pumped air as a compressor and the twp were connected by a rocking linkage.. Starting consisted of cranking a handle to pull the pistons apart and to compress a bloody great spring.,.,...as I remember, it was 21 1/2 turns. That number was very important to know, because that's when the spring released, throwing the pistons together at Mach 2.5! If everything was set up right, the air would be compressed between the pistons, fuel would be injected and off we'd go!
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