Rotary Machine and Internal Combustion Engine

Abstract

The rotary displacement device has a rotating piston and a rotating housing that has a fixed vane. The cylindrical rotor is eccentrically placed in relation to its cylindrical housing. The gas and air flow goes through the hollow-centered shaft via channels in the rotor. The sealing grid in the displacement space is improved to minimize the friction and thereby gain power and better efficiency.

Description

THE ROTARY MACHINE

The present invention refers to rotary displacement devices with rotating pistons like used in compressors, blowers, air engines and rotary internal combustion engines. This invention is such a device that can be used in the mentioned applications, particularly rotary internal combustion engines, which in the last mentioned application can be compounded of two or more devises according to the present invention of which at least one has the function as a compressor and the other or, whenever applicable, the others has the function of a power unit or expander or expanders, that is to transfer heat energy to kinetic energy. The units work together so the fluid can pass from one to the other. A transmission ensures the housings to rotate.

On the market there are a great number of rotary devices of various principles, one of each with its special advantages and disadvantages. As rotary displacement engine the Wankel engine is one of the most known and the most developed of all.

THE OBJECT OF THE INVENTION

Concerning compressors it is only the traditional piston compressor which have the best efficiency compared to other designs, because of the effective sealing arrangement of piston rings. Many rotary designs have failed because of sealing problems. Complex geometries prevent a simple sealing arrangement. For instance it is well known that the Wankel engine has gone through many difficulties to solve their sealing problem. However rotary designs have other advantages as smooth running, light design, and low friction. The present invention also facilitates a simple device. It is an object of the invention to combine the best features of most compressor designs for a wide application. In order to accomplish that, it is therefore an object of the invention to improve the sealing grid in the displacement space and to minimise the friction and thereby gain power and better efficiency. Another object of the invention is, in the application of a rotary combustion engine, to create a simple device with a large possibility of development towards better environment qualities, especially use of hydrogen.

In the use of conventional and other alternative fuels the aim is to develop higher efficiency with preserving the great application area of the conventional piston engine.

Inner and Outer Rotor Design

The invention has a cylindrical rotor eccentrically placed in relation to its cylindrical housing characterised in that the mentioned housing also is rotating. The mentioned inner rotor is resting and rolling on the inner wall of the outer housing (contact line) and makes to rotate by a vane fixed on the housing. It is that mentioned housing because of the fixed vane that receive, alternatively in the case of an engine application, give the driving power. The inner rotor is thereby not burdened with any other torque than its own friction. The gas and air flow goes through the hollow-centred shaft via channels in the rotor. That makes the housing be designed without openings or ports for the mentioned flow. The co-rotation reduces the friction substantially.

Displacement Variation

The eccentrically mounted rotor forms a variable volume between following surfaces besides lateral walls: 1) the inner surface of the housing, 2) the vane and 3) the outer surface of the rotor. This space has of obvious reasons its largest cross-sectional area diametric opposite the contact line between the rotor and its housing. That causes the volume within mentioned surfaces to change in relation to the vane approaching or removing the contact line. That feature is particularly useful in the mentioned combustion engine, where one or more compressor units and power or expander unit/s can be joined together so it paradoxically creates compression in an expanding volume in the combustion chamber. That is beneficial in the endeavour to approach an isothermal (constant temperature) compression. That can be accomplished by intercooler/s between the units. It explains in detail below. It is also simple to turn the revolving direction of a compressor design for an application as an expander for converting a fluid pressure to a rotating movement, for instance compressed air, or a fluid from an external combustion.

Sealing

As the vane 4 is fixed between the lateral walls and towards the housing there is no need of an apex seal or side seals as in the Wankel engine. The rings and the grooves may be designed with a cross cut angel of around 45 degrees in order to seal properly in the corner, that is both against the lateral walls and as close as possible against the inner surface of the housing 1 (contact line).

Cooling

The outer rotor has peripheral fins for efficient cooling during rotation.

The central parts of the rotor together with the common shaft and the end of the vane facing the centre of the rotor are in open contact with the open air, which by the fan action caused by the rotation contributes to cool the machine. The vane itself has also air channels for cooling. The gas flow is adjusted by valves.

The Internal Combustion Engine.

During the years many alternative combustion engines have appeared to eliminate the disadvantages that conventional reciprocating piston engines are afflicted with. The gas turbine, the Stirling engine and the Wankel engine are some examples of alternative engines being researched upon and still are being invested money on. But these engines have limited application areas where their special advantages can be utilised. The environmental demands are given gradually larger importance and many have stumbled and failed because of other problems, why the reciprocating piston engines still are the dominating engines in the market.

Concerning the application as a rotary internal combustion engine the aim is to make a better combustion process and to facilitate the use of alternative fuels, for instance hydrogen. Furthermore the aim is to essentially increase the efficiency, which indirect affects the environment by lower fuel consumption and lower pollution.

Disadvantages of the Reciprocating Piston Engine.

1. Single Volume Process

In contemporary piston engines all the four strokes: intake, compression, combustion and exhaust, take place in one single volume. It can be regarded as preferable to share the strokes with more volumes in order to achieve best efficiency.

2. Crank Gear

The crank gear of the piston engine and thereby the connected piston motion and the inertia of the reciprocating pistons have in several decades been object to brain efforts of inventors and scientists for better solutions. Therefore many suggestions to rotary engines have appeared since many years back.

3. Efficiency

Another area, which constantly is developing is the efforts to increase the efficiency. According to the thermodynamics the Carnot-process has the highest theoretical thermal efficiency. Rudolph Diesel tried in his time to make his engine to work according to that process in a large extent as possible. But it is difficult to apply that process on common engines. It has also a long time been known, that the efficiency and thereby the fuel consumption, is largely connected to the compression ratio. The development has therefore gone towards manufacturing engines with still higher compression ratio. But the limiting factor has been fuel qualities and, concerning diesel engines, the high combustion pressures, which demand heavy designs. Despite the high top pressures seems to be an important parameter for a high efficiency, it has on different ways been an endeavour to level those peak pressures towards a higher mean pressure. But it is difficult to accomplish that in the traditional piston engine.

4. Compression Rate

A combustion engine, and then especially the Otto engine, has its optimal efficiency at a given speed and load. At part load the efficiency is decreasing because of the inlet pressure is decreasing by throttling. That lowers in turn that compression pressure, which gives the best efficiency. Therefore it has been regarded desirable to vary the compression ratio at different load. The proposed engine according to the present invention solves that problem in an easy way.

Another problem is the high compression temperature that arises when striving after higher compression ratio. That increases the compression load and gives higher N0x pollution. Therefore it has been tried with different system of intercoolers.

5. Energy of Exhaust Gases

The exhaust gases in the common piston engine have, when they leave the engine, still a large content of energy. An Englishman, James Atkinson, introduced in the end of the 1800^th century a piston engine with a complicated crankshaft, which extended the expansion stroke in order to utilize that content of energy. It was then observed that those engines had a higher efficiency than comparable engines at that time. As the crankshaft became clumsy, it was tried in the following generations of engines to approach the Atkinson cycle by controlling the compression and expansion intervals via opening and closing of the valves, which however do not give the same result as in the “genuine” Atkinson engine.

6. Scavenging

The scavenging of the exhaust gases in the space between the piston at top dead center, TDC and the cylinder head is another area which has resulted in comprehensive efforts of improvements. Full scavenging can hardly be achieved in a traditional piston engine, as the exhaust valve closes at TDC and it remains burnt gases in the mentioned space.

7. Moment Arm

The length of the moment arm affects the torque. The longer arm the greater torque. The force line of action is almost perpendicular to the axis of rotation at TDC and some degrees of rotation thereafter. That makes the moment arm very small, and then when most of the energy is generated. Much of the power is therefore wasted,

8. Valves

Filling and exhaust require valves and contemporary piston engines have two or more valves in each cylinder. That makes the engine more complex and expensive.

Solutions.

1. Single Volume Process

The present invention is very useful for alternative applications. As the machine can work as compressor, air engine or expander, it is possible to combine two or more machines for the very best efficiency. This description shows only two solutions, one proposal with two machines and another with three machines.

2. Crank Gear

The present invention is designed as a rotary and hence a traditional crank gear is not needed. It solves mentioned problems and are as combustion engine built according to the so-called Brayton principle, that is an engine with two units where intake and compression are done in one unit and expansion and exhaust are done in the other. Another proposal shows, as mentioned above, three machines: two compressors and one power unit (expander). The rotary principle makes it possible to avoid the inertia of the crank gear and therefore facilitate a higher speed.

3. Efficiency

In the case of three machines, the Carnot-process can be approached, which is the process with the highest efficiency. The compression is done more or less isothermal in the first compressor with an intercooler, and step two in the second compressor (adiabatic) where the compression is done isentropic, when a valve is opened in the expander unit, where compression continues to a certain level. Then the valve closes and the gas ignites. When the vane in the expander moves from the contact line and forward, the volume in the compression/combustion chamber thus changes from zero to the desirable volume. Despite of space increment the pressure in the expanding volume can be kept constant or even a pressure increment can take place. This seems to be a paradox, but depends of the open connection with the compressor in the moment when the valve is open and the space decrease in the compressor is larger than the compression/combustion chamber increment in the expander. This lowers the compression heat and thus minimizes the NO x emissions and increases the efficiency.

4. Compression Rate

The compression rate is variable during the engine run by a device, which affects the opening and closing times of the intake valve via external influence. That is an advantage for varied load conditions.

The process has no turning fluids as in the reciprocating engine but it resembles more the process of a gas turbine. That can make the compression ratio be higher than contemporary engines and the combustion pressure more leveled.

5. Energy of Exhaust Gases

The present invention makes it easier to achieve beneficial parameters in that the size relation between the units, compressor/s and expander, can mutually be chosen freely depending on desired application. For instance the expander can have a larger expansion rate than the compression rate in the compressor. All the energy of the fluid can therefore be utilized.

6. Scavenging

The exhaust volume in the expander goes during every revolution towards zero volume, when the vane moves up to the contact line. This arrangement is an advantage for gas exchange. There will be no mixture of fresh and burnt gases. The intake valve has no connection with the exhaust port and the design is therefore secure from an undesirable ignition. This would be an advantage for use of hydrogen.

7. Moment Arm

The invention has no crank gear but a fixed vane with a moment arm of constant length that transfers the power to a revolving motion without losses.

8. Valves

Only one valve is needed for opening and closing the intake fluid. The exhaust channel is constant open.

Several designs within the wide area of the present invention would be possible. Concerning combustion engines is here below, for the sake of simplicity, only described two alternatives: alt 1; one compressor with an intercooler+one expander connected with each other via a common hollow-centred shaft, FIG. 12, and alt 2; one compressor, named “K1” with an intercooler+another compressor, named “K2”+one expander, connected with each other in the same way, schematically shown, FIG. 16.

DESCRIPTION OF THE DRAWINGS

FIG. 1. shows a rotary machine, for instance a compressor, in enlarged section view along the line A-A in FIG. 2.

FIG. 2. shows the same machine from intake front.

FIG. 3. shows the same machine in perspective view.

FIG. 4. shows the same machine in section view along the line B-B in FIG. 5.

FIG. 5 shows the same machine in a side view.

FIG. 6 shows a rotary machine designed as an expander in a combustion engine in section view along the line C-C in FIG. 7, displaying the valve mechanism.

FIG. 7 shows the same expander in a side view.

FIG. 8 shows the same machine in section view along the line D-D in FIG. 9, disclosing the exhaust channel and an ignition devise (here a spark plug).

FIG. 9 shows the same machine in side view as in FIG. 7.

FIG. 10 shows the same machine in section view along the line E-E in FIG. 11, disclosing part of the mechanism of opening and closing the valve (12 and 13).

FIG. 11 shows the same machine in a side view as in FIG. 7 and FIG. 9.

FIG. 11a shows an expander in section view along the line F-F in FIG. 11b.

FIG. 11b shows the same machine in front view.

FIG. 12 shows an engine with compressor, intercooler and expander connected to each other.

FIG. 13 shows a rotor in perspective view displaying the sealing arrangement and the abutment halves for the vane.

FIG. 14 a) shows an expander rotor in perspective view with an example of valve arrangement mounted and b) shows the rotor in exploded view disclosing the valve mechanism.

FIG. 15 shows the valve lifter and adjustable cam 13: a) in exploded view, b) the cam in upper position, and c) in lower position.

FIG. 16. Shows a schematic view of an isothermal compressor (K1) with an intercooler and an adiabatic compressor K2 and an expander connected to each other.

FIG. 17-21. Shows schematic views of the fluid in different positions of a revolution.

FIG. 22. Shows a diagram with volume and pressure curves. It serves only to roughly enlighten the process of a combustion engine according to the present invention and not to be regarded as a final analysis.

WORKING DESCRIPTION FOR A ROTARY MACHINE

The machine consists of a rotor 2, which is eccentrically placed in a housing 1 with contact against said housing 1 (the contact line 2a) and which rotor 2 has a diameter less than said housing, so it thereby creates a space between the outer circumference of the rotor 2 and the inner circumference of the housing 1. By that eccentric arrangement the mentioned space has its largest section surface diametrical opposite the contact line 2a. On the inner circumference surface of the housing 1 there is a vane 4, which object is to create, together with the surrounding surfaces of the rotor 2 and housing 1, variable volumes. Another object of said vane is to bring the rotor 2 to rotate by a recess in the mentioned rotor made for said vane. The housing 1 and rotor 2 are each of them hanged in a bearing arrangement mounted on the base 14. The rotor 2 is not burdened with any torque except that caused by friction. A transmission 9a transmit power to and alternatively from (depending on application) an axis 9b for external apparatus. The rotor 2 has intake and outlet channels 6, which each of them and independent of each other lead via other connected channels 5 to openings on each side of the vane 4 on the outer surface of the rotor 2. The rotor 2 has on each side axial recesses 5a, which purpose is for balancing and for evacuating of heat via holes 9 out to the open air. As compressor there is a back-pressure valve 17 mounted, FIG. 20. The vane 4 is surrounded by two abutments halves 8 in the rotor slot. They receive an oscillating movement from the vane 4 in relation to the rotor 2. The sealing arrangement 16, FIG. 13, consist of one ring on each side of the rotor 2 fitted in grooves. The rings and the grooves may be designed with a cross cut angel in a section view of around 45 degrees in order to seal properly partly against the lateral walls and partly as close as possible against the inner surface of the housing 1.

Working Description as Combustion Engine.

As combustion engine the invention can be designed with one or more compressors and one or more expanders connected to each other. This description deals in the first alternative only with one compressor and one expander, FIG. 12. In the compressor take inlet and compression place and in the expander compression, combustion and exhaust. In the second alternative there is another compressor K2 connected, schematically shown in FIGS. 17-21. Between the units there is possible to connect an intercooler 18 for reducing the compression heat. The expander unit has, besides mentioned design above, also an intake valve 7 and ignition arrangement 10, FIG. 6 respective FIG. 8. An example of valve arrangement shows in FIG. 14 and FIG. 15. The valve lifter arm 11 has a roller 12, which, when rolling on the adjustable cam 13, transfer power, via the arm 11 to the valve 7, which then opens.

Compressor and expander are in this example of application so connected to each other that when the vane 4 in the compressor has rotated and created a volume decrease and thereby a certain pressure, the valve 7 opens by the adjustable cam 13 affected by an external device (here exemplified by a simple handle 15). The flow continues into the combustion volume in the expander, where ignition and combustion occur and the working phase starts.

The process starts with inlet of air or gas into the compressor, FIG. 12, through the channels 6 in the hollow-centered shaft. Rotor channels 5 on each side of the vane 4 emerge into the corresponding volume ahead of, respective after the vane 4. From the compressor the compressed fluid leads via an intercooler 18, in the first mentioned alternative to the expander, and in the second alternative to another compressor K2 for further compression into the expander.

The second alternative are more described in detail as follows.

The aim with two compressors is to approach the Carnot cycle, which is well known in the thermodynamics world for having the best theoretical thermal efficiency. The first compression phase is there recorded as isothermal, that is to say the warmth generated is rejected to the open air by a cooling arrangement. The following phase is isentropic (adiabatic) compression. The heat generated is now preserved in as a large extent as possible before combustion. That is not possible to accomplish in contemporary piston engine, where all the phases occur in one volume. Therefore the present invention disclose a solution with two compressors. The first compressor K1, FIGS. 16-21, has large cooling surfaces and combined with an intercooler 18 rejects all the heat generated to the environment (isothermal phase). The second compressor K2 has a smaller volume compared to K1 so the volume relation between the two is determined to an optimal rate for best efficiency. K2 receives the precompressed fluid from K1 (curve a in FIG. 22) and continues the compression into the expander to the desirable level.

See FIGS. 17-22. In the compressor K1 has intake and compression phases started a new revolution. In the expander is the working phase still going. The three units has reached the position in FIG. 17 and diagram FIG. 22. The valve 7 in the expander is closed. Notice in the figure the valve 7 is sketched with en open flap in order to mark an interrupted fluid into the expander).

In position FIG. 18 the pressure, curve b, has reached the level shown in diagram FIG. 22. The valve 7 has just opened in the expander and compression continues simultaneously in K2 and the expander up to position in FIG. 19, where the fluid is interrupted by the closing valve and combustion starts. The curve for the fluid pressure is sloping upwards from around 180 degrees to around 240 degrees (0 to around 80 in the expander) of a revolution indicating a pressure increase in the expander. By following the curves for volume alteration it is evident to see that the volume decrease is larger in the compressor/s than the volume increase in the expander. Hence the pressure increases.

There is a channel 19 in the rotor K2, which opens when the expander valve 7 has closed and lets the fluid pass over into the intake volume, FIG. 20. In position FIG. 21 a new revolution starts. A back valve 17 prevents the remaining fluid pressure in the intercooler to flow back into K1 but flows instead into K2. The intake pressure K2 increases again around position in FIG. 18.

Claims

1. A rotary displacement machine for evacuating or compressing a fluid or alternatively converting a fluid pressure to a rotating movement comprising:

a cylindrical housing and a rotor eccentrically disposed in relation to said housing generating a contact line,

the housing a vane and lateral walls being fixed together and thereby generating a rotating unit surrounding the rotor.

2. The rotary machine according to claim 1, wherein the rotor shaft is hollow centered generating channels for in- and outlet of the fluid.

3. The rotary machine according to claim 1 wherein the rotating unit via a transmission transmits or alternatively receives power by the fluid pressure affecting the vane respectively being affected by the vane.

4. The rotary machine according to claim 1 wherein each of two parallel and annular sides of sealing rings is, at an imagined extension towards a circle center of the rings, generating a cone and a third side of the rings is tightening against lateral walls.

5. The rotary machine according to claim 1 wherein the rotary machine is a combustion engine that has a fluid being compressed in an simultaneously expanding combustion chamber before ignition.

6. The rotary machine according to claim 5 wherein the combustion engine has a fluid that is being cooled during the compression phase in an simultaneously expanding combustion camber before ignition.

7. The rotary machine according to claim 1 wherein the rotary machine has a valve (7) that has variable opening and closing times in order to generate a variable compression rate.