WO2017014640A1

WO2017014640A1 - Rotary heat engine and compressor

Info

Publication number: WO2017014640A1
Application number: PCT/NO2016/000021
Authority: WO
Inventors: Ivan Jurjevic
Original assignee: Crmic
Priority date: 2015-07-20
Filing date: 2016-07-07
Publication date: 2017-01-26
Also published as: NO340080B1; NO20150948A1

Abstract

A rotary heat engine with substantially no reciprocating elements is disclosed. The engine comprises a compression vane-type rotary arrangement in a cylindrical compression chamber arranged to simultaneously executing intake and compression stroke in by a compression vane with seal and a compression rotor with seal separated sections of the compression chamber. The engine comprises further a transfer channel for transferring a compressed charge from above mentioned compression arrangement to a combustion vane type rotary arrangement in a cylindrical combustion chamber simultaneously executing combustion/expansion and exhaust stroke in by a combustion vane with seal and a combustion rotor with seal separated sections of the combustion chamber.

Description

Rotary heat engine and compressor.

Field of invention

The present invention relates to heat engines. More specifically, the invention relates to a thermodynamic heat-to-work converter ("prime mover") with substantially no reciprocating elements. The present invention relates also to a compressor.

Background

Over the years a number of attempts have been made to design a heat engine with essentially no reciprocating parts in order to avoid vibration and noise and to enable higher revolutions. The best known example of such engines with a confined working space is the Wankel-engine, while open working space engines include the steam and gas turbine.

While turbine engines are well established in their markets (steam turbines for electric power generation and gas turbines as aircraft engines) there is less use of rotary heat engines of the types with closed working space. The Wankel engine is - as far as the author knows - only used in some very few vehicles and in the field of model airplanes.

Summary

The present invention relates to a rotary heat engine with substantially no reciprocating elements. The engine comprises a compression vane-type rotary arrangement in a cylindrical compression chamber arranged to simultaneously executing intake and compression stroke in by a compression vane with seal and a compression rotor with seal separated sections of the compression chamber. The engine comprises further a transfer channel for transferring a compressed charge from above mentioned compression arrangement to a combustion vane type rotary arrangement in a cylindrical combustion chamber simultaneously executing combustion/expansion and exhaust stroke in by a combustion vane with seal and a combustion rotor with seal separated sections of the combustion chamber.

Each rotary arrangements comprises a single vane rotating inside the respective chamber about a first axis centric to the chamber, the vane substantially sealing to said circumferential outer wall and circular side walls; a rotor with a cut-out cavity for the vane to fit into, the rotor being fixed to a rotating shaft constituting a second axis, the shaft being supported non-centric (non-coaxial) to the cylindrical chamber, where a profile of the cavity permits a toggle movement of the vane (8,10) in relation to the rotor caused by the centric location of first axis and the non-centric location of second axis. Both rotary arrangements are rotationally synchronized.

The rotational synchronization is preferably achieved through fixed attachment to a single rotating shaft which is common for both rotary arrangements.

In the above heat engine, in at least one of said compression chamber or combustion chamber said rotor seal and/or said vane seal can be arranged to be temporarily removable out of the rotational way of the vane prior to the vane passing by the location of the rotor seal.

In one embodiment the cylindrical compression chamber is longer than the cylindrical combustion chamber to achieve increased compression of a charge to be fed into the combustion chamber.

The transfer channel can be equipped with a valve to control timing of transfers through the transfer channel, and the valve can be a sliding valve or rotating valve.

The vanes can be kept centric to the cylindrical chamber by a pair of vane rings, where each ring is rotationally supported in a circular recess centric to the chambers side walls.

The vane rings can further be used to control sub-processes in the engine in that a shape (a cam mounted onto the ring or a hole through the ring) is shaped onto/into the ring. The shape can be operable to operate engine elements. For instance, a hole through at least one of the vane rings, together with an opening of said transfer channel, may constitute a rotating valve to control fluid flow through the transfer channel.

Another aspect of the present invention is a compressor according to the same features as the compression vane-type rotary arrangement described herein in connection with the disclosure of the heat engine.

Brief description of the drawing

Below a number of embodiments of the inventive engine will be described which will be easier understood in connection with the attached drawing, where the figures show:

Fig. 1 a schematic cross-section of an engine according to the present invention, the cross-section being placed through the rotational center, i.e. along the center of the power shaft;

Fig. 2 a cross-section of the cylindrical compression chamber of the engine at

A-A in fig.l;

Fig. 3 a cross-section of the cylindrical combustion chamber of the engine at B- B in fig. 1; Fig. 4 a cross-section of a chamber, indicating pressure sealing means inside the chamber between vane and chamber wall (B) and rotor and chamber wall (A);

5 air pressure relationships in the intake/compression chamber;

6 combustion product pressure relationships in the combustion/exhaust chamber;

Fig. 7 'dual' cross-section, showing vanes in both chambers and thus giving an indication of the angular relationship between the vanes;

8a details about sealing between vane and circumferencing chamber wall; 8b Detail A: rotor seal embodiment in bottom of chamber; detail B: vane seals to circumference and side walls of chambers;

8c vane with sealing approaching rotor sealing;

8c vane seals passing rotor seal; and

Fig. 9a, b vane/rotor arrangement for occupying same location at the shaft.

Detailed description of preferred embodiments

Any mentioning of 'upper', 'lower', 'bottom', 'vertical' and similar in the following description relates - unless otherwise stated - only to the embodiments of the invention as disclosed in the drawing, i.e. 'bottom' does mean the bottom of the engine as shown in the drawing; it does not imply, that embodiments of the inventive engine with 'bottom-up' are not covered. The subject matter of this specification generally is not dependent on any orientation in relation to gravitational forces.

Mechanical arrangement

Both main parts of the inventive engine -compression part and combustion part - have substantially the same mechanical structure. Therefore the description below will sometimes not make any distinction between compression arrangement and

combustion arrangement.

Fig. 1 is a schematic cross-section along the rotating shaft 6 of the engine. The figure further indicates the outer engine shell, front wall 1 and rear wall 5 with bearings for the shaft 6, and a wall 3, the wall separating a cylindrical compression chamber 4 (intake and compression) from a cylindrical combustion chamber 2 (expansion and exhaust) and including a channel 13 for passing a compressed charge from the compression chamber 4 to the combustion chamber 2. Below, all three walls 1, 3, 5 are also called 'side walls' when a further distinction is not necessary. The figure also indicates two cross-sections A-A and B-B referred to below. Note that the engine shaft 6 is not centric to the chambers 2,4. Fig. 2 shows a cross-section through the cylindrical compression chamber (A-A in fig. 1). Inlet 11 permits an oxidizer/working fluid (working fluid=non-combustible gas fraction, N2) mix (usually and hereinafter: "air") to be drawn into the chamber. Three dashed lines indicate two slightly offset cross hairs on the vertical center line of the chamber.

The upper cross hair indicates both the rotational center of a compression rotary vane 8 (sometimes also called "rod") and the center of the compression chamber. Since these two centers are identical, a spring-loaded sealing means at the outer end of the vane 8 will always stay in sealing contact with the cylindrical wall of the compression chamber 4 with only marginal movement in radial direction. Details about how the vane 8 can be supported in a preferred embodiment at the center of the chamber and the sealing means will be given later in this specification.

The lower cross hair - non-centric to the compression chamber - indicates the rotational center of a cylindrical compression rotor 7. At the point of least distance from the compression rotor 7 to the circumference wall of the compression chamber 4 (at the bottom of the chamber in the figs.) there is a seal sealing the rotor 7 to the chamber wall. It will be discussed in more detail below. The engine shaft 6 is the rotating shaft of the compression rotor 7 and thus is off-center to the chamber as already mentioned above.

From the compression chamber 4, a channel 13 penetrating the separating wall 3 allows a charge of compressed air - or in some embodiments a mix of oxidizer, working fluid and fuel - to be fed into the combustion chamber 2. A valve mechanism well-known to the skilled man, is used for timing of charge transfer from compression chamber 4 to combustion chamber 2 through channel 13. More about the valve later in this document.

The compression rotor 7 and the compression vane 8 reside on the - along the shaft 6 - same shaft position. As seen in Fig. 1, they fill both substantially the complete length of the cylindrical chamber. It is therefore necessary, that the compression rotor 7 has a cut-out giving space for the compression vane 8 in all angular positions. This cavity is only indicated in later figs. 9a-b and discussed in connection with these figs.

It should be noted, that the compression arrangement described above also could be used as a motor-driven compressor of its own, without the below-described combustion arrangement.

Fig. 3 is very similar to fig. 2 and shows a cross-section through the combustion chamber (B-B in fig. 1). The outlet 12 permits the expanded combustion products to leave the chamber. Three dashed lines indicate two slightly offset cross hairs here too, indicating the two rotation centers of combustion rotary vane 10 and combustion rotor 9, respectively. Compressed gas charge enters the chamber from the compression chamber 4 through the valve-controlled channel 13.

In case of the engine embodiment being designed for an Otto-process or similar, fuel is added to the air inside or close to the channel 13; in a different embodiment, fuel is added before compression close to the inlet 11 to the compression chamber 4. For embodiments with diesel-type processes, the fuel is injected into the combustion chamber 2 close to the channel 13.

Fig. 4 indicates sealing between the rotating parts and the chamber 2, 4 outer (circumferential/cylinder) wall. A more detailed description will follow in connection with figs. 8a-d. It will be understood, that the seals A, B (vane chamber walls and rotor/ chamber walls) divide the chambers into two volumes: from vane seal B to rotor seal A in rotational direction (right side of applicable figs.),the chamber is used for compression and exhaust ejection, respectively, while the left side (from rotor seal A at the bottom of the chamber in rotational direction to the vane seal B) is used for intake or combustion/expansion, respectively.

Functional description

Intake and compression

Fig. S is used to explain the function of the compression part. Note, that sealing details are omitted from fig. 5 and 6, specifically the rotor seal A (see fig. 4) closing the narrow gap at the bottom of the chambers between chamber wall and rotor is omitted. The rotation direction is clockwise as indicated by an arrow. As mentioned above, the rotors 7, 9 of both compression and combustion arrangement are in this preferred embodiment rotationally fixed mounted to the same shaft 6 and thus synchronized. Separate shafts synchronized by gears and/or chains or other means well-known to the skilled man could be employed as an alternative.

After the compression vane 8 has passed the air inlet 11 opening, there exists a space delimited by the vane/vane seal, the rotor seal at the lowest point of the chamber, the chamber wall from seal to vane, the rotor surface from rotor seal to vane and sections of the side walls delimited by vane, rotor seal and chamber wall and rotor surface as described above. Since the vane rotates, the distance from rotor to seal increases to a section of the chamber where the distance from chamber wall to rotor surface also has increased. Both increased dimensions result into a larger volume which in turn results into air being drawn into the space. Even after the vane has passed the top and the distance from chamber wall to rotor surface is decreasing, the volume further increases due to the distance from rotor seal to vane still increases. When the vane passes the opening of transfer channel 13, a direct connection from air inlet 11 through the chamber 4 and transfer channel 13 to the combustion chamber exists, and at that point the channel 13 must be closed by some means to avoid back flow from the combustion chamber. In one embodiment, this can be done by a valve based on a sliding mechanism. Other solutions will be disclosed later in this specification

It should be noted, that once a charge has been delivered to the compression chamber, and until the vane has passed the air intake opening 11 , there is no useful combustion air compression and no air intake (suction) going on. This means again, that there is no need for any rotor seal and vane seal, and in one embodiment, the seals during this phase of the rotation can temporarily be removed. For instance the rotor seal could be lowered into a cavity of the cylinder wall and/or the vane seal could be withdrawn into the vane to ease the passing of the vane seal on its way from right to left side of the chamber. The embodiment shown in the figs, however, discloses a classical solution with spring-loaded seals being flexibly supported such that they can retract against the spring force if needed to pass the rotor seal.

The inventors consider the rotational angle for this phase (from having delivered a charge to having passed the intake 11 and starting a new compression) being preferably 60°, based on engine power, engine type (diesel cycle, otto cycle) and engine rpm (revolutions per minute).

Further, after the vane has passed the opening of channel 13, there exists a small space between vane and rotor seal without any outlet besides potential leakage through seals. From this fact, it would in some embodiments be an advantage or even necessary, to remove/open the rotor seal. In one embodiment, this opening - lowering the rotor seal until it loses contact with the rotor can be pressure operated: the increasing pressure between vane and rotor seal lowers the rotor seal against the spring load into the recess in the chamber wall.

When the vane has passed the inlet 11, there is a confined volume given by vane and rotor seal, chamber wall and rotor surface between vane and seal, and sections of the side walls limited by the above. During rotation, the vane moves clockwise in the direction to the rotor seal and in the later part of the rotation, the distance from chamber wall to rotor surface decreases. Both effects reduce the confined space, i.e. gas/air trapped in this space is compressed. When the vane 8 approaches the opening of the channel 13 and a sufficient pressure of the charge has been built, the previously mentioned valve in the transfer channel to the combustion chamber 2 is opened, the compressed charge leaves the compression chamber 4 for the combustion chamber 2. Combustion/expansion and exhaust

Fig. 6 is used to describe the function of the combustion chamber 2. Again, an arrow indicates the direction of rotation. When the combustion rotary vane 10 has passed die inlet from channel 13 from the compression chamber 4, the compressed charge is transferred into the space limited by the vane, the rotor seal at the lowest point of the chamber, the chamber wall from seal to vane, the rotor surface from seal to vane and sections of the side walls delimited by vane, seal and chamber wall and rotor surface. Then the channel valve is closed and the charge ignited (Otto-like process)/fuel injected (diesel-like process). The rising pressure from the heated working gas forces the vane 10 in this phase to rotate until it passes the outlet 12, after which the exhaust gases are released while the vane continues to rotate to the bottom/rotor seal and further to the inlet to repeat the process with a new charge.

During the working phase, when the vane - before passing the exhaust outlet 12 - is pushed by the expanding gases, the vane pushes the remaining exhaust gas of the previous combustion cycle out of the combustion chamber.

The sealing issues regarding the rotor seal in the combustion chamber are very similar to those of the compression chamber as described above.

Somewhat similar to the process in the compression chamber, when the combustion rotary vane has passed the outlet opening and approaches the rotor seal at the chamber bottom, there is no need for the seals being tight at least for the short period when vane seal passes rotor seal. In one embodiment of the invention, thus the seals could be retracted for this period and closed again when vane seal has passed rotor seal and before prior reaching the opening of the transfer channel 13.

Fig. 7 shows a combination ('dual cross-section') of the vanes 10, 8 of both

combustion 2 and compression chamber 4. The combustion rotary vane 10 is approximately 60° ahead of the compression rotary vane 8 in rotational direction. In general, the passing of a compressed charge from the compression chamber 4 through the transfer channel 13 should take place when the charge is highly compressed (taking least space, i.e. compression vane approaching transfer channel opening and at the same time the combustion vane has just passed the inlet from the transfer channel, allowing an ignition of the charge at high pressure and much expansion volume left in the combustion chamber.

More details about sealing

Fig 8a shows dual 'piston-ring '-type seals for the vanes 8,10. The (black) sealing leafs - referenced 14 in later figure 8b - located in slots in the vane are pushed against the chamber wall by springs. Abrasion at wall or the seals itself will be compensated by the springs IS.

Fig. 8b, detail B discloses in a perspective view that such a seal type also applies to the sealing against the side walls 1,3,5. Fig. 8b, detail A shows a simplified seal block to be located inside a recess of the chamber wall at the bottom of the respective chamber where the rotor 7, 9 has the least distance from the circumferencing chamber wall.

Fig. 8c shows the vane 8, 10 with seals approaching the rotor seal.

When the sealing leafs of the vane (spring suspended inside slot(s) in the vane) during rotation touch the rotor sealing element (spring suspended inside a recess of the chamber wall) as shown in Fig. 8d substantially at the point of the chamber with least distance from chamber wall to rotor, all the in this embodiment three sealing elements can be pushed up/down into the recess/slots, allowing the vane to pass the rotor seal.

Other embodiments to solve this way of the vanes 8, 10 passing the rotor seal have been disclosed above: at this position of the vane in the chamber, there exists no need for a functioning sealing (the charge is delivered to the combustion chamber, intake of new air has not yet started), and instead of the vane leafs hitting the bottom seal, the leafs of the vane and/or the bottom seal could be retracted mechanically (by a cam, see later) or pneumatically. The latter could be solved by using the fact that both in the combustion and the compression chamber, a pressure is built up when the vane has passed the transfer channel 13 opening or the exhaust opening, respectively, in the small space between the vane and the bottom/rotor seal. This pressure could be used by means well-known to the skilled man to retract the leafs.

Supporting the vane at the chamber center and coexistence of vane and rotor.

Figs 9a-b show details in perspective view of the solution how vane 8, 7 and rotor 10, 9 could coexist while rotating about different rotation centers and taking up largely the same space. The rotor 7, 9 is rotating about and fixed to a shaft 6, the shaft being located non-coaxial to the cylindrical chamber. The vanes are rotating about a center ~ the center of the chamber - which seemingly penetrates the rotors. All figures so far do not show the inventive solution which shall be discussed now.

For a first approach to make this possible, there is a cut-out/cavity in the rotor which gives space for the vane in a straight upwards direction - see Fig. 9b. The vane 8, 10 is equipped with a vane ring 17 on each side, the vane rings 17 defining with their common center the rotational axis of the vane. When the vane is inserted into the cutout of the rotor - the ring-equipped end first - the vane rings 17 lie onto each side of the rotor. However, the vane rings 17 will also act as/be arranged with pressure seals (simmer rings or similar) between vane ring 17 and rotor.

The inner diameter of the rings is dimensioned sufficiently wide, that the engine shaft 6 can be inserted through both vane rings 17 and the shaft-supporting hole in the rotor 7, 9 even the rotor shaft is non-centric to the chamber. In a preferred embodiment, surface areas of the vane rings 17 are used to control sub- processes of the engine. For instance, the valve opening/closing the channel 13 could be controlled by a cam-like element arranged on the surface of the vane rings 17 to open close dependent on the position of the vane. Furthermore, in another embodiment of the invention, the outer diameter of at least one of the vane rings 17 could be such wide that it covers the opening of the transfer channel 13. In this case, suitable localization of holes penetrating the vane ring 17 can act as a rotating valve to open/close the channel 13. The skilled man will know about further possible valve solutions.

The vane rings 17 are supported - as can be seen in fig. 9b - by a circular recess in the side walls 1, S, and - not visible - at the back of the separating wall 3, the recess also showing the opening for the shaft and the recess being centric to the chamber; the rings constitute the rotation shaft of the vane. By the centering, the vane rotating in the chamber will always be close to the chamber walls without any need for very long sealing leafsl4.

Also the side of the vane rings 17 facing the side walls is equipped with pressure sealing means between vane ring 17 and side wall recess. The skilled man will however understand, that the sealing means need not be mounted to the vane rings 17, but can equivalently also be mounted into said supporting recesses in the side walls.

The four pressure sealing means - two on each side of each of the two vane rings 17 - pressure-isolate the engines shaft area from the pressure of the compression and combustion processes. The sidewall-parts of rotor seals as discussed above and the side- wall leafs of the vane seal (see fig. 8b) thus only need to be coordinated with the vane ring 17 seals which are concentric to the chamber, thus making the pressure sealing relatively easy (need not handle eccentricity).

With reference now to figure 9a, when rotor and vane are assembled as written above, and both are to rotate together in the chamber, the different rotation axis for rotor 7, 9 and vane 8, 10 make the vane move inside the rotor slot/cut-out This movement inside the cavity of the rotor during one revolution of the shaft comprises that the vane is retracted into the rotor/pushed out again and also has from zero to a few degrees slope in relation to the axis of the cut-out. The slope requires the cavity being wider than the vane part at the inner end of the vane. This can be spotted in Fig. 9a. On the other hand, due to compression and combustion, there is a pressure difference over the vane, and the vane transfers this pressure as a torque onto the rotor. Since the vane is supported by the vane rings 17 at the inner end and by the cut-out opening at the rotor outer circumference, the vane should fit snug to the rotor cut-out opening. The skilled man will know how to achieve the correct shape of both vane and rotor cut-out to fulfil these requirements. Because of high pressure difference from one side to the other side of the vane, a seal 16 is required to inhibit gas bypassing from one side of the vane through the cavity to the other side of the vane. In figure 9a this seal is indicated as a semi-cylindrical pieces 16 fitting into semi-cylindrical grooves inside the rotor cavity.

The compression factor in the compression part can be adjusted by changing the relationship of compression chamber 4 length (along the direction of the shaft 6) and combustion chamber 2 length, provided the chambers and the mechanics therein have substantially identical dimensions otherwise. This can be used to 'supercharge' the engine or to adapt a compressor to given rpm/torque specification.

Claims

P a t e n t c l a i m s

1 A rotary heat engine with substantially no reciprocating elements,

characterized by

• a compression vane-type rotary arrangement in a cylindrical compression

chamber (4) arranged to simultaneously executing intake and compression stroke in by a rotor with seal, a compression vane with seal separated sections of the compression chamber,

• a transfer channel (13) for transferring a compressed charge from said

compression arrangement to

• a combustion vane type rotary arrangement in a cylindrical combustion chamber (2) simultaneously executing combustion and exhaust stroke in by a combustion vane with seal and a combustion rotor with seal separated sections of the combustion chamber,

each rotary arrangements comprising:

• a single vane (8,10), rotating inside the respective chamber (2,4) about a first axis centric to the chamber, substantially sealing to said circumferential outer wall and circular side walls,

• a rotor (7,9) with a cavity for the vane to fit into, the rotor (7,9) being fixed to a rotating shaft (6) constituting a second axis, the shaft being supported non-centric to the chamber, where a profile of the cavity permits a toggle movement of the vane (8,10) in relation to the rotor caused by the centric location of first axis and the non- centric location of second axis,

where both rotary arrangements have means for rotational synchronization.

2 Heat engine according to claim 1 , characterized by

the rotational synchronization being achieved through fixed attachment to a single rotating shaft (6) being common for both rotary arrangements.

3 Heat engine according to one of the preceding claims, characterized by in at least one of said compression chamber (4) and combustion chamber (2) said rotor seal and/or said vane seal being arranged to be temporarily removable out of the rotational way of the vane (8,10) prior to the vane passing by the location of the rotor seal.

4 Heat engine according to one of the preceding claims, characterized in that the cylindrical compression chamber (4) is longer than the cylindrical combustion chamber (2) to achieve increased compression of a charge to be fed into the

combustion chamber. 5 Heat engine according to one of the preceding claims, characterized in that said transfer channel (13) is equipped with a valve to control timing of transfers through said transfer channel.

6 Heat engine according to claim 5, characterized in

that said valve is at least one of a sliding valve and a rotating valve.

7 Heat engine according to one of the preceding claims, characterized in that said vanes (8, 10) are kept centric to the chamber (2,4) by a pair of vane rings (17), each ring rotationally supported in a circular recess centric to the chambers side walls (5,1,3).

8 Heat engine according to claim 7, characterized in

that at least one of said vane rings (17) is arranged to control sub-processes in the engine by applying a shape to at least one part of the ring, the shape being operable to operate engine elements.

9 Heat engine according to claim 8, characterized in

that said shape is at least one hole through at least one of the vane rings (17), the hole - together with an opening of said transfer channel (13) - constituting a rotating valve to control a fluid flow through said transfer channel.

10 Heat engine according to claim 8, characterized in

that said shape is a cam at a rim of the at least one of the vane rings (17), the cam being arranged to operate engine elements.

11 A compressor according to the compression vane-type rotary arrangement as given in the preceding claims.