WO2014191781A1

WO2014191781A1 - Rotary-piston internal combustion engine

Info

Publication number: WO2014191781A1
Application number: PCT/GE2013/000004
Authority: WO
Inventors: Ramzan GOYTEMIROV
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-05-28
Filing date: 2013-05-28
Publication date: 2014-12-04
Anticipated expiration: 2015-11-28

Abstract

The present invention pertains to four-stroke non-poppet valve rotary internal combustion engines operating by gasoline fuel, natural gas, diesel fuel or hydrogen and can be used for simplification of structure, ensuring reliable and smooth operation of engines with any number of cylinders. The engine comprises a cylinder block group mounted within a housing on rotation supports with combustion chambers facing a rotational center; a rim with a curvilinear, closed inner running track being in contact with pressure-bearing running rollers mounted on pistons; a gas distribution spool-type core fixed against rotation in a central opening of the cylinder block group and having ports on its outer periphery for supplying the air-fuel mixture or air, ignition spark, and/or for injecting the fuel into the combustion chambers; A common port for successively exhausting from the combustion chambers the exhaust gasses is provided. The ports for supplying and exhausting in combination occupy no more than 180° + - 10 degrees on the angular sector of the core, and the port for ignition spark and/or fuel injection is disposed at diametrically opposed sector of 180° + - 10 degrees. The spool-type core is mounted in freely suspended state and can have conical shape, be spring-loaded and made of heat-resisting ceramics.

Description

Rotary-piston Internal Conbustion Engine

Technical field

The present invention pertains to engine technology and can be used in developing four- stroke non-poppet valve rotary internal combustion engines operating by gasoline fuel or natural gas, and particularly, by diesel or hydrogen fuel.

Background of the art

Among the conventional rotary engines, Wankel engine has found real application. Some attempts have been made to implement engines that are titled as orbital ones according to the US patent 3,787,150 of Sarich. Main advantage of the Wankel engine is small sizes at preset power. As compared with piston engines, the engine comprises twice as less movable parts, and, accordingly, it is potentially more reliable and is lower in cost. The engine is characterized by use of planet motion of a rotor (piston) disposed within a housing, surface of which is made in the shape of epitrochoid. Such structural solution enables to implement 4-stroke cycle of operation without the need in special gas distribution mechanism to be used. Chambers are sealed by radial and end sealing plates pressed against the housing by centrifugal forces, gas pressure, and band springs.

However, three basic disadvantages are intrinsic to the Wankel engine that can hardly be overcome, or this is associated with heavy spending. The first disadvantage is that the lengthened combustion chamber does not allow combusting the air-fuel mixture in effective way which leads to excessive fuel consumption. The second disadvantage is that vibrations of plates of radial seal created in motion of the rotor leads to wearing of epitrochoidal inner surface of the housing and forms wavelike distortion thereof. The third disadvantage is non-uniform heating of the housing associated with displacement of the combustion chamber with respect to the housing produces heat stresses leading to the epitrochoid distortion. The orbital engine patented by Sarich (US3,787,150) has also a substantial structural drawback in that motion of blades that partition the operating volume of the engine into isolated chambers is translational with respect to the housing. At the same time, the blade ends fastened in the rotor perform motion similar to a sliding member in a sine mechanism. Such motion of the blade allowed Sarich to provide sealing of the blade in the housing in the simplest way. However, the method of fastening and sealing the blades in the rotor appeared to be very complicated, and, importantly, non-reliable. The patent US3,703,344 discloses a structure of a non-poppet valve engine wherein admission and exhausting is performed via channels and cut-outs through a drive cam of a power shaft, pivot joints mounted in the rotor, blade plates, pivot joints mounted in the housing, and a housing. The disclosed system has limitation in gas distribution possibilities and in mounting sealing elements to prevent effluxes. Another orbital non-poppet valve engine is disclosed in patent RU2285127, wherein a rotor is mounted off-center on a power shaft. A spool-type disk plays a role of a gas distribution mechanism that is coaxially disposed relative to the power shaft and has end recesses made along arcs of different radial circles. The disk rotates contrary to the power shaft rotation direction with twice as less speed and creates a cyclogram of operation of an engine having the odd number of combustion chambers.

However the engine can be accomplished as non-poppet valve one only if it is provided with odd number of combustion chambers, and all of the drawbacks in relation with sealing and wearing of the rotor engines still remain therein.

It is known also a non-poppet valve, four-stroke, four-piston internal combustion engine according to the Japanese patent JPH07269367. It lacks a valve system of gas distribution and of a crankshaft, and, therefore, it is small-size and light weight. The gas distribution, i.e. admission and exhaust, is performed via two windows made in a spool-type disk having a sliding end wherein a sealing, and accordingly, pressing must be provided. This friction inevitably makes the construction non-reliable, taking presence of elevated temperatures into consideration. The prior art that is closest to the present invention by structural features is a rotary internal combustion engine and its cooling method according to the patent US3,828,740. The engine according to US3,828,740 comprises a rotary cylinder block group with four radially arranged cylinder-piston group having combustion chambers facing the center; a housing with a rim having a curvilinear, closed running track that is symmetrical with respect to the rotational center and having contact with pressure-bearing running rollers mounted directly on each piston; a spool-type gas distribution core having ports on outer periphery for supplying air-fuel mixture or air and ignition spark or for injecting the fuel into two oppositely disposed combustion chambers at once fastened on the housing in the central opening of the cylinder block group with clearance and with means for sealing the junction. Each combustion chamber is provided with one inlet opening facing the rotational center opposite to the core ports for receiving air-fuel mixture, air, ignition spark or injectable fuel. The engine is provided with a passageway for exhaust gasses to be exhausted successively from each combustion chamber in lower "dead point" after completing the working stroke, i.e. a piston remains fixed in a cylinder during turning of the block group by 90° degrees and new mixture or air is blown to push out exhaust gasses partially mixed therewith. Eventually, the combustion products, like in well-known "two-stroke" principle, are partially remained in the cylinder and present in the process of power/expansion during the working stroke.

The operation of the aforementioned engine is similar to that with the two-stroke cycle characterized by higher expenditure of fuel having a drawback - Its structural features are not suitable for performing four-stroke cycle in view of economy and smoothness of operation.

It is of vital importance to develop a rotor-type internal combustion engine that would have enhanced basic parameters of a conventional piston engine, i.e. to reduce sizes and weight, improve efficiency, reduce fuel expenditure and content of the carbon oxide in exhaust gasses, improve operation smoothness, noiselessness, enhance reliability and serviceability standards.

Objective of the invention

The present invention has for its objective to simplify the construction and ensure reliable and smooth operation in a four-stroke and non-poppet valve engine having any number of cylinders that can operate by different types of fuel (petroleum, gas, diesel, hydrogen).

Disclosure of the invention The objective is achieved by the rotary-piston internal combustion engine comprising a cylinder block group on rotation supports mounted in the engine housing, the group having radially arranged cylinder-piston groups with a combustion chambers facing a rotational center; a rim mounted in the housing with a curvilinear, closed inner running track being symmetrical relative to the rotational center and being in contact with a pressure-bearing running rollers mounted on each piston directly or by means of a connecting rod supported by a lever mounted on a pivotal support on the cylinders block group; a gas distribution spool-type core having circular cross-section that is fixed on the housing to prevent its rotation and mounted in the central opening of the cylinder block group with running clearance and means for sealing a junction and having a port on its outer periphery for supplying the air-fuel mixture or air and a port for supplying ignition spark and/or injecting the fuel into the combustion chambers; each combustion chamber being provided with one inlet opening facing the rotational center for receiving the air-fuel mixture, air, ignition spark and/or injectable fuel; a passageway for successively exhausting the exhaust gases from each combustion chamber; the engine being characterized in that

1. in the engine having the said rim with the running track in the shape of an oval or rhomb with rounded ends or in the shape of spaced apart half circles, for exhausting the exhaust gasses successively from each combustion chamber,

a one single common passageway made on the same outer periphery of the core in the form of one more port through the same inlet matching opening is provided, and said two ports for supplying the fuel mixture or air and for exhausting together occupy an angular sector of no more than 180° on the outer periphery of the core and are spaced apart with the interval equaling to the central angle not less than that occupied by the inlet opening, the same exhaust opening, relative the rotational center, of each combustion chamber; and, at the same time, the sector which is not less than said angle on the outer surface of the core occupies said port for supplying the ignition spark and/or fuel injection and it is disposed in the sector of 180° diametrically opposed to the location of said two ports; said gas distribution spool-type core fixed on the housing to prevent its rotation is positioned in the central opening in freely suspended state;

said gas distribution spool-type core is of conical shape, spring loaded in axial direction and is mounted in a central opening having conical shape in the cylinder block group; channels for admission and diverting of cooling liquid is made in the spool-type gas distribution core;

said spool-type gas distribution core is made of a heat-resisting alloy or ceramics and/or the central opening of the cylinder block group is provided with a sleeve made of a heat- resisting alloy or ceramics;

the means for sealing the junction between the spool-type gas distribution core surface and the central opening of the cylinder block group is made as sealing rings, e.g. zigzag in shape, disposed in non-pivotable manner in annular channels of the core, and are made of heat-resisting materials;

the pistons are mounted in the cylinders arranged with an axis offset relative to the axis of rotation of the cylinder block group by a value exceeding the sum of radiuses of the cylinder and the spool-type gas distribution core in case the number of cylinders in the engine is no more than four;

the pivotal support of the floating lever supporting each connecting rod is disposed in the cylinder block group at the side opposite to the offset of the cylinders axis from the rotational center and is spaced apart from it to the extent that upon positioning the piston in the upper "dead point" of the cylinder, the floating lever together with the connecting rod create an obtuse angle towards the rotational center;

finnings are made at the ends and/or in the periphery of the cylinder block group, and blow down ports for cooling the engine by air are made in the housing;

oil is doped in the housing at the level upper to that of the running track of the rim, and channels are provided therein for draining out/running off an air-oil mixture to cool the oil and to forcibly return it so as to ensure access of the fresh air to the housing interior. The cause and effect relationship between the features characterizing the present invention and the achieved result is as follows.

One single spool-type core disposed in the cylinder block group center in freely suspended state can serve to supply air-fuel mixture or air through one single port to the combustion chambers; one single fuel injector or ignition spark and one single port in the same core for exhausting the exhaust gasses are sufficient; the spool-type core has not to be pressed to the cylindrical contact surfaces for sealing because its free disposition in the cylinder block group opening allows to make the surfaces and the junction with minimum operational clearance; the ports for fuel supply, ignition and exhausting are arranged along the angular sectors such that four-stroke cycle is accomplished in each cylinder successively, and thereby any number of cylinders that can be disposed within the predetermined sizes of the engine can be employed.

The spool-type core is of conical shape for ensuring the required sealing of the junction and enhanced compression in the combustion chambers.

It is possible to enable admission, circulation and diverting of cooling liquid in a simple manner in the motionless core, which can be made of a heat-resistant material, such as ceramics, to improve its life time. The serviceability is improved by the possibility to directly remove, clean and replace the core.

The offset cylinders relative to the rotation axis enable, on the one hand, to better utilize the internal volume and reduce the sizes of the engine. On the other hand, on thus arranged pistons and connecting rods supported by the floating levers, pressure-bearing rollers can be mounted and pivot axes of the levers can be arranged in a manner as to create auspicious interaction between the rollers and inclined surfaces of the rim. Due to the extra tilt back action of the pressure-bearing rollers onto the rim, the upper "dead point" can be passed and the force application arm can be increased faster, that creates a torque, to compare with conventional engines with a crankshaft. This is important in view of reducing the influence of blowing loads on the smoothness of operation of Diesel engines, and particularly, engines that operate by hydrogen fuel.

Exemplary embodiments The present invention will now be explained in greater detail with the reference to embodiments, with the aid of the accompanying drawings, wherein:

Fig.l shows front section of the four-cylinder engine according to the present invention;

Fig.2 shows front section of the eight-cylinder engine according to the present invention; Fig.3 shows longitudinal cross section of the engine according to the present invention;

Fig.4 shows front section of the four-cylinder engine according to the present invention and passage of each combustion chamber beside the ports of the gas distribution core in four-stroke cycle;

Fig.5 shows comparative diagram of upper "dead point" passage speed of the pressure- bearing rollers mounted on the pistons arranged offset with respect to rotational center after explosion.

In accordance with the claims, the engine comprises a cylinder block group 3 mounted within a housing 1 on rotation supports 2. Pistons 4 are accommodated in radially arranged cylinders 5 forming combustion chambers 6 facing a rotational center 7 of the cylinder block group 3. Pivotally connected to the pistons 4 are connecting rods at another ends of which pressure-bearing running rollers 9 are mounted. The connecting rods 8 are supported by floating levers 10, pivotal supports of which are positioned in the cylinder block group 3. Another end of each floating lever 10 is pivotally connected to the intermediate part of the respective connecting rod 8. The pivotal support of the floating levers 10 which are arranged in the cylinder block group 3 is disposed at a^' distance from the rotational center 7 so that when positioning the piston 4 in the upper "dead point" (i.e. closest to the rotational center 7) the floating lever 10 creates an obtuse angle a with the connecting rod 8 at the rotational center 7 side opposite to the block group 3 rotation direction. For the purposes of interacting with the pressure bearing running rollers 9 and thereby converting the reciprocal motion of the piston 4 into the rotary motion of the block group 3, a rim 11 having a curvilinear, closed, symmetrical relative to the rotational center 7 inner operational running track 12 is mounted in the housing 1 (or is directly constructed therein). It can have the shape of oval or rhomb with rounded ends, or in the form of, e.g., spaced apart half circles. The shape of the closed running track 12 is determined by four-stroke operation cycle which must conditionally be divisible by two. In the central cylindrical opening 13 of the block group 3, a spool-type gas distribution core 14 is positioned. The core 14 is fixed to prevent its rotation in the housing 1; however, it is not fastened and is disposed within the opening in free-suspended state to ensure minimal running clearance in the junction, that is necessary for sealing and ensuring the required compression in the combustion chambers 6. Rings 15 that seal the junction are mounted such that they are not capable of turning on the core 15. All ports and channels needed for ensuring the four-stroke operation cycle as well as for liquid cooling of the engine are made on the outer cylindrical surface 14 of the core. The supply port 16 is made in the angular sector not exceeding 90°, destined for the suction stroke or for blowing the air-fuel mixture or air. Exhaust port 17 is made in the angular sector not exceeding 90°, destined for exhausting the exhaust gasses. Both of the ports 15 and 17, jointly, including the angular distance β between them, occupy not more than 180° of the angular sector. A port 18 destined for spark supply and/or fuel injection is disposed on the outer surface of the core 15 in a remaining 180° sector destined for the compression and expansion strokes, approximately in the middle thereof, and can be provided with a spark plug 19 and/or fuel injector 20. Each combustion chamber 6 is provided with an opening 21 that occupies the angular sector y, destined for receiving the air-fuel mixture, air, ignition spark and/or injectable fuel as well as for exhausting the exhaust gasses. In order for the channels (ports) for admission 16 and exhausting 17 to be clearly delimited, the angular interval β between them is made greater than the angular sector γ which occupies an opening 21 of the combustion chamber 6. The cylinders 5 with the pistons 4 can be offset relative to the rotational center 7 in the direction of the rotation of the block group 3 with value of A which is greater than the sum of the cylinder 5 diameter d and the diameter D of the outer surface of the spool-type gas distribution core 14 so as to reduce the sizes and ensure enhanced smoothness of the engine operation. To ensure the enhanced compression in the chambers 6, the outer surface of the spool- type gas distribution . core 14 can be made conical and can be positioned within the opening 13 of the block group 3 and can be spring-loaded in axial direction (this embodiment not shown in the figures). In the core 14, channels 22 for admission, circulation 23 and diverting of the cooling liquid are made. Desirably, the core 14 must be made of heat-resisting material, for example of heat-resisting ceramics, and the inner opening of the block group 3 is provided with a sleeve 24 made of heat- resisting material. The engine can be provided with air cooling means made as finnings 25 in the cylinder block group 3, at the ends and/or in the periphery, and blow down ports 26 are made in the housing. A toothed ring 27 can be made on the rim 11, and on the axes of the pressure-bearing running rollers 9, gear-wheels 28 can be mounted to allow the rollers 9 to run in the running track 12 without slipping. The engine can be provided with a air-oil cooling means for the purposes of which oil is doped in the housing 1, upper the running track 12 of the rim 11, and channels for running-off the air-oil mixture for cooling the oil and channels for forcibly returning the oil and accessing the fresh air to the housing interior (this embodiment not shown in the figures) are made therein.

The engine operates in the following manner. During the rotary motion of the cylinder block group 3, the pistons 4 are performing forcible reciprocal motion within the rim 11 in the manner defined by the running track 12 shape. The combustion chambers 6 of each cylinder 5 successively pass in circle beside ports 16, 18 and 17 of the core 14. When passing the port 16 along the angular sector about 90°, the air-fuel mixture or air is sucked or blown through the opening 21 into the combustion chamber 6 and the piston 4 moves in radial direction from the rotational center 7 (first stroke). Next, along the next angular sector up to about 180°, the piston 4 moves in radial direction towards the rotational center 7, the air-fuel mixture or air is compressed (second stroke) and, at the end of the compression (in the upper "dead point" of the piston 4), a spark is supplied by the spark plug 19 through the port 18, or fuel is initially injected by the injector 20 and then spark is supplied, or diesel fuel is injected without supplying the spark. Thereafter, along the next angular sector up to about 270°, detonation, explosion or combustion of the fuel and expansion of gasses, i.e. working stroke of the piston 4 from the center (third stroke) occurs. This time, the pressure-bearing roller 9 acts on the curvilinear running track 12, creates a torque and brings about further forcible rotation of the cylinder block group 3. Next, along the next angular sector up to 360°, the piston 4 performs radial motion towards the rotational center 7 and the exhaust gasses exhaust successively from each combustion chamber 6 through the port 17 (fourth stroke).

It means that one revolution of the cylinder block group corresponds to one working stroke and forcible rotation by 90°. Therefore, while the present engine can have any number of cylinders, at least four cylinders are necessary for continuous forcible rotation. In case of four cylinders contained in the present engine, four working strokes are performed in one revolution and the engine in this case can be considered more high-speed than a conventional four cylinder four-stroke engine with a crankshaft wherein two working strokes are performed per one revolution of the shaft. Due to this peculiarity, the engine is well suited to hydrogen fuel having the property of faster propagation of explosion to compare with petrol.

When using hydrogen (or diesel fuel) the impact loads in the upper "dead point" of the piston are more noticeable and for leveling this undesirable phenomenon it is envisioned in the present engine some structural measures set out in the claims 7 and 8. In the comparative diagram depicted in fig. 5 it can be seen that the pressure-bearing rollers 9 mounted on the connecting rods 8 when the pistons 4 are offset from the rotational center 7 pass the upper "dead point" more rapidly after explosion and the blowing force P is converted into a torque with relatively steeper "grade", that acts favorably to ensure the smoothness of the engine operation. The obtuse angle a created between the floating lever 10 and the connecting rod 8 in the beginning of the working stroke causes additional roll-over action of the pressure-bearing roller 9 onto the running track 12 of the rim 11, creating this greater "arm" at this moment. It means that the applied force arm which cereals torque increases more rapidly than, for example, in an engine with a crankshaft. The present invention allows to resolve the following technical tasks in a complex manner: in a non-poppet valve mechanical system of gas distribution four stroke cycle, any number of cylinders, use of conventional groups of . cylinders and pistons are combined in a single device that allows the most perfect combustion, smoothing impact load in the upper "dead point" (which is particularly important for diesel engines and those operating by hydrogen). Owing to this the following technical results are achieved: (a) reduction of the engine sizes; (b) decrease of the friction losses; (c) simplification of the construction; (d) substantial decrease of the power expenditure on the drive of the gas distribution mechanism to compare with an engine provided with a valve; (e) reduction of noise and vibration; (f) increase in engine speed due to the accomplishment of one working stroke in each cylinder per each revolution; (g) no need in forcible lubrication while the engine can be lubricated by air-oil mixture created by the oil freely fed to the housing, not necessarily of high quality.

Claims

1. A rotary-piston internal combustion engine comprising a cylinder block group on rotation supports mounted in the engine housing, the group having at least one radially arranged cylinder- piston group with a combustion chamber, facing a rotational center; a rim mounted in the housing with a curvilinear, closed inner operative running track being symmetrical relative to the rotational center and being in contact with a pressure-bearing running roller mounted on each piston directly or by means of a connecting rod supported by a lever mounted on a pivotal support on the cylinders block group; a gas distribution spool-type core having circular cross-section that is fixed on the housing to prevent its rotation and mounted in the central opening of the cylinder block group with running clearance and means for sealing a junction, and having a port in its outer periphery for supplying the air-fuel mixture or air and a port for supplying ignition spark and/or injecting the fuel into the combustion chambers; each combustion chamber being provided with one inlet opening facing the rotational center for receiving the fuel mixture, air, ignition spark and/or injectable fuel; a passageway for successively exhausting the exhaust gases from each combustion chamber, characterized in that in the engine having the said rim with the running track in the shape of oval, or rhomb with rounded ends or in the shape of spaced apart half circles, for exhausting the exhaust gasses successively from each combustion chamber, a one single common passageway made in the same outer periphery of the core in the form of one more port through the same matching inlet opening disposed in the same core is provided, and said two ports for supplying the air-fuel mixture or air and for exhausting together occupy an angular sector of 180°±10 in the outer periphery of the core and are spaced apart with the interval equaling to the central angle not less than that occupied by the inlet opening, the same exhaust opening of each combustion chamber, relative to the rotational center; and, at the same time, the sector which is not less than said angle in the outer surface of the core occupies said port for supplying the ignition spark and/or fuel injection and it is disposed in the sector of 180°±10, diametrically opposed to the location of said two ports.

2. The engine in accordance with claim 1, characterized in that said gas distribution spool-type core fixed on the housing to prevent its rotation is positioned in the central opening in freely suspended state.

3. The engine in accordance with claim 1, characterized in that said gas distribution spool-type core is of conical shape, spring loaded in axial direction and mounted in a central opening having conical shape in the cylinder block group.

4. The engine in accordance with claim 1, characterized in that channels for admission and diverting of cooling liquid are made in the spool-type gas distribution core.

5. The engine in accordance with claim 1, characterized in that said spool-type gas distribution core is made of a heat-resisting alloy or ceramics, and/or the central opening of the cylinder block group is provided with a sleeve made of a heat-resisting alloy or ceramics.

6. The engine in accordance with claim 1, characterized in that the means for sealing the junction between the spool-type gas distribution core outer surface and the central opening of the cylinder block group is made as sealing rings, e.g. zigzagging, disposed in non-pivotable manner in annular channels of the core, and made of heat-resisting materials.

7. The engine in accordance with claim 1, characterized in that, in case the number of cylinders in the engine is no more than four, the pistons are mounted in the cylinders arranged with an axis offset relative to the axis of rotation of the cylinder block group by a value exceeding the sum of radiuses of the cylinder and the spool-type gas distribution core.

8. The engine in accordance with claims 1 and 7, characterized in that the pivotal support of the floating lever supporting each connecting rod is disposed in the cylinder block group at the side opposite to the offset of the cylinders axis from the rotational center and is spaced apart from it to the extent that upon positioning the piston in the upper "dead point" of the cylinder, the floating lever together with the connecting rod create an obtuse angle towards the rotational center.

9. The engine in accordance with claim 1, characterized in that finnings are made at the ends and/or in the periphery of the cylinder block group, and blow down ports for cooling the engine by air are made in the housing.

10. The engine in accordance with claim 1, characterized in that oil is doped in the housing at the level upper to that of the running track of the rim, and channels are provided therein for draining out/running off an air-oil mixture to cool the oil and to forcibly return it so as to ensure access of fresh air to the housing interior.