Field of the invention

The invention relates to a rotary combustion engine, i.e. the design of rotary drive systems for combustion of liquid or gaseous fuels.

Background of the Invention

The combustion engines together with combustion turbines belong to the basic driving units used for creating a rotating or a sliding motion putting other parts of machines and equipment into subsequent motion.

The basic and the most common types of applied combustion engine are piston engines divided to two-stroke and four-stroke combustion engines according to the number of working cycles executed during one crankshaft revolution. These engines are provided with a combustion chamber with a piston which is connected to the crankshaft by means of a connecting rod. The basic created movement of these engines is the sliding piston motion which puts the crankshaft into the rotational movement using the connecting rod. Two-stroke engines have a simpler design, are lighter and usually have higher specific power at the same speed. The combustion process is carried out in the mode above and below the piston alternatively, which means that it is not possible to use the standard piston lubrication by oil from the oil sump, and the fuel mixture must be enriched by a lubricating medium which is also combusted. Therefore, the main disadvantage of the two-stroke engine is its smokiness and higher contents of harmful and unburnt fuel mixture components in exhaust gases.

These disadvantages in the production of exhaust gases are eliminated by four-stroke engines where the combustion process is more environmentally-friendly and it is not necessary to enrich the mixture by the lubricating medium. The disadvantage is represented by only one working motion of the piston during one crankshaft revolution, higher weight, etc. The disadvantage of the limited amount of combustion processes during one crankshaft rotation is eliminated by the standard design of the rotary combustion engine. The Wankel engine with a rotating rotor on the eccentric and a fixed housing is known from the technical practice. The Wankel engine is a combustion engine in which the piston having the shape of a convex triangle changes the volume of the chambers by rotating in a hollow oval housing. Concurrently, suction, compression, expansion and exhaust are carried out in the chambers while the piston edges open and close the suction and exhaust openings. The Wankel engine provides a rotary motion without a crank mechanism and does not need any distribution equipment. With the same power, it can be produced more economically, it is more compact and weighs approximately by one third less than standard piston engines. The rotating parts can be almost perfectly balanced, which results in an exceptionally smooth operation and minimum noise. The main disadvantage of rotary combustion engines is the issue with sealing the contact area between the cylinder wall and the rotary shaft edge. The main advantage of rotary combustion engines is the fact that their design and internal forces enable to increase the power by simply increasing the speed, which is not enabled by standard piston combustion engines with the sliding piston motion. Another advantage is the theoretically possible option of any number of combustion chambers along the circumference of the rotary shaft.

Many shape versions of the rotary shaft indicating also the number of created combustion chambers are known from the technical practice. One of them is the CZ 21688 U1 document when the rotary shaft forms two oppositely arranged combustion chambers, which are put into a synchronized combustion process. Both chambers work simultaneously and the processes ongoing in both chambers are exactly the same at the same point in time.

A piston engine formed by separate combustion engines arranged in a star or circle with independent combustion engines with own combustion chamber, piston assembly and own injection, ignition and exhaust systems is known from the CN 109252946 document. Engines are formed to have two opposite combustion chambers moving the piston between two extreme opposite positions up and down. The connecting rods put the common eccentric wheel with an oscillating ring into the rotational movement. The main advantage of this solution is a very good balancing of the whole engine and the smoothness of its operation. However, the disadvantage is its substantial technical complexity, and thus its purchase price.

The disadvantages of rotary combustion engines of the standard Wankel embodiment is also the necessity to use light fuel which is less environmentally-friendly. This disadvantage is solved by rotary combustion engines with an external combustion chamber or with an external pre-chamber. Such an example is the engine according to EP2551448 with a modified design for use of heavy -type fuel, i.e. diesel oil. For this purposes, the engine is provided with a pair of injectors when one injects the fuel into the combustion chamber and the other one into the pre-chamber with an incandescent body. The pre-chamber is the site of the explosive reaction which spreads also to the mixture in the combustion chamber.

Another rotary engine type is a rotary combustion engine with an external combustion chamber according to CS 197395. This engine has the rotor embodied as a rotary shaft located in a hollow cylindric housing provided with external combustion chambers. The rotary shaft is then formed as a blade-one with side-closed impeller blades. The fuel mixture ignition by a spark plug or by ignition in the external combustion chamber generates pressure gas which expands outwards to the inner expansion chamber formed by the shaft body and sides connected by a pair of adjacent impellers. This way the shaft is put into a circular motion when, in a certain position, the inner chamber gets connected with the exhaust manifold and the combustion products are released into the exhaust manifold under their own pressure. The fuel mixture inlet is brought to the external combustion chamber. The main advantage of this engine is a smoother run-up and pressure distribution in the engine, thus lower engine vibrations. The advantage is also a better distribution of temperatures generated during the process of combustion and the option to cool hollow blades.

The main disadvantage of rotary combustion engines is the leakage consisting in insufficient separation of the oil sump and the lubricating medium from the combustion area. Another disadvantage is a low efficiency of so-far produced rotary combustion engines nowadays reaching approximately 50%. The last but not least important disadvantage is the considerable weight of the engine resulting mainly from the heavy weight of the rotary shaft. However, the large mass of the material dissipates the generated heat better.

Therefore, the task of the invention is to create such a rotary engine which is lightweight with multiplied power of the rotary engine in proportion to its weight, and when the temperature transfer and the cooling process are not decreased. The higher performance should be reached also by the fact that the resulting rotary engine is able to carry out more expansions within one impeller revolution. At the same time, it is required for the lubrication chamber to be completely separated from the combustion chamber. An equally important task of a new technical solution of the invention is to make the run-up and run-down of the pressure forces generated during the combustion process as smooth as possible, and simultaneously, to better distribute the resulting temperatures to the whole engine mass.

Summary of the invention

The deficiencies of the currently known equipments are overcome by the described rotary combustion engine. The rotary combustion engine consists of a hollow cylindric engine housing which inside is provided with a rotor having side-closed impeller blades. The side closure together with adjacent areas of two adjoining side-closed blades forms individual separated inner expansion chambers. On the outer side, the hollow cylindric housing is provided with at least one external combustion chamber with a spark plug and a fuel mixture inlet. Furthermore, the hollow cylindric housing is provided with an exhaust manifold from the outer side. The upper housing part of the engine is formed to create an oscillation chamber fitted with an array of blades. These are arranged against the direction of the impeller blades and together with the engine housing form individual separated outer expansion chambers. The upper housing part has a shape of a shell whose section increases in the direction of engine rotation from the area of the combustion chamber location to the area of the exhaust manifold edge.

In a preferred embodiment, the rotary combustion engine rotor consists of a main rotary shaft which is integrally fitted with an impeller wheel. The impeller wheel is driven by expanded gases formed during the process of fuel mixture combustion, and transmits its rotary motion to the main rotary shaft. The main rotary shaft then transmits the torque to other drive elements, e.g. gearboxes or axles. The rotary combustion engine in this arrangement is able to carry out more expansions within one impeller wheel revolution, which multiplies the rotary combustion engine power with only a small increase of this rotary combustion engine weight.

In another preferred embodiment, the impeller blades of the impeller wheel are solid, have the same length and the same angle of inclination. The impeller blades of the impeller wheel also have equal mutual spacing along the entire perimeter length of the impeller wheel. The impeller blades are deflected from the upper housing part so that they are inclined against the direction of the impeller wheel rotation.

In another preferred embodiment, the blades of the oscillation chamber have different lengths. The blade length gradually increases so that the shortest is closest to the combustion chamber location. On the contrary, the blade located closest to the exhaust manifold is the longest, i.e. when directing the fitting of blades in the direction of the rotor rotation from the area of the combustion chamber location to the area of the exhaust manifold location. In this direction, the blades are gradually longer and longer. These blades are tightly connected with the inner surface of the upper housing part, with which they have the same inclination angle. The distances between the located blades are identical along the entire length of the oscillation chamber, wherein the blades are inclined to the oscillation chamber so that they are always inclined in the direction of the impeller wheel rotation.

In the following preferred embodiment, the oscillation chamber blades and impeller wheel blades are so long that they never touch the rotary engine during operation. The distance between the blades and impeller blades in the point of the shortest mutual distance is in order of pm.

In another preferred embodiment, the fuel mixture inlet consists of a compressor which presses the supplied air-and-fuel mixture and injects the resulting compressed fuel mixture using an injection nozzle to the combustion chamber where it is ignited. In another preferred embodiment, a lubrication chamber provided with openings for the pressure lubricant inlet and outlet is located between the impeller wheel and the housing. To prevent the contact of the fuel with the combusting fuel mixture, the lubrication chamber is provided with a seal.

The main advantage of this invention is the combination of a standard rotary combustion engine with an external combustion chamber with an oscillation chamber element. Thus formed rotary combustion engine has a much higher ratio of the produced power related to the weight of its own rotary combustion engine due to the impeller blades of the impeller wheel than in currently available rotary combustion engines. The reason is mainly the fact that this rotary combustion engine is capable of more expansions during one revolution of the impeller wheel. At the same time, the design of this rotary combustion engine enables a smooth and even temperature transmission, which means the engine cooling process is not impaired. Another advantage is that the formed rotary combustion engine has higher efficiency and at the same time, its lubrication chamber is completely separated from the combustion chamber. The last but not least advantage of this rotary combustion engine is the fact that the run-up and the run-down of pressure forces formed during the combustion process are maximally smooth, which limits the engine vibrations and simultaneously better dissipates the arisen temperatures to the whole mass of the rotary combustion engine.

Clarification of drawings

The invention will be explained in more detail by means of the drawings which illustrate:

Fig. 1 side view of a rotary combustion engine in section, Fig. 2 front view of a rotary combustion engine in section.

Examples of Invention Embodiments

It is understood that the specific examples of embodiments of the invention described and illustrated below are presented for illustrative purposes and not as a restriction of the examples of embodiments of the invention to those examples. Experts skilled in the art will find or be able to identify, using routine experimentation, a greater or lesser number of equivalents to the described examples of embodiments of the invention.

According to the representation of the invention in Figs. 1 and 2, the applied-for rotary combustion engine 1 as well as all similar equipments consist of a hollow cylindric housing 3 of the rotary combustion engine 1 on the outer side. This hollow cylindric housing 3 forms the outer shell of the rotary combustion engine 1, which can be provided with other elements, e.g. not shown cooling. According to a not-shown example of the invention embodiment, this can consist of upper auxiliary finning for air blast cooling or auxiliary outer casing where the cooling liquid will flow between the casing and the housing 3. The hollow cylindric housing 3 is provided with a rotor inside, and this rotor is provided with side-closed impeller blades 5. The side closure is a part of the rotor design and together with adjacent areas of two adjoining impeller blades 5 forms individual separated inner expansion chambers 10. On the surface, the hollow cylindric housing 3 is from its outer side provided with at least one external combustion chamber 6 which is fitted with at least one spark plug wherein the external combustion chamber 6 has a fuel mixture inlet 8. Furthermore, the hollow cylindric housing 3 is provided with an exhaust manifold 9 from the outer side.

According to the representations in Figs. 1 and 2, the upper part 19 of the housing 3 of the rotary combustion engine 1 is formed so that is creates an oscillation chamber 2. The oscillation chamber 2 is from its inner side fitted with an array of blades 11, which are directionally arranged against the direction of impeller blades 5 and together with the housing 3 of the rotary combustion engine 1 form individual separated outer expansion chambers 12. The upper part 19 of the housing 3 has a shape of a shell whose section increases in the direction R of the engine rotation from the area of the combustion chamber 6 location to the area of the exhaust manifold 9 location.

According to the example of the invention embodiment depicted in Figs. 1 and 2, the rotor of the rotary combustion engine 1 consists of a main rotary shaft 4 which is integrally fitted with an impeller wheel 13. The impeller wheel 13 is fitted with previously stated impeller blades 5 and is functionally driven by expanded gases formed during the fuel mixture combustion in the combustion chamber 6, which expand to the inner expansion chambers 10 and put the impeller wheel 13 into the rotating motion. The impeller wheel 13 then transmits this rotational motion to the main rotary shaft 4, and the main rotary shaft 4 then transmits the torque to other drive elements, like gearboxes, axles or other motion equipment known by the person skilled in the art. The main rotary shaft 4 is located on bearings 20 in the housing 3 of the combustion engine 1.

Thus arranged rotary combustion engine 1 is capable of doing more expansions during one revolution of the impeller wheel 13, which results in a multiplied power in proportion to its mass, i.e. the weight of the rotary combustion engine 1 itself.

According to the same invention embodiment, the impeller blades 5 of the impeller wheel 13 are solid, have the same length and have the same inclination angle. The impeller blades 5 of the impeller wheel 13 also have equal mutual spacing along the entire perimeter length of the impeller wheel 13. The impeller blades 5 are deflected from the upper part 19 of the housing 3 so that they are inclined against the direction R of the impeller wheel 13 rotation, i.e. against the direction of expanded gases from the process of fuel mixture combustion.

According to the example of the invention embodiment depicted in Figs. 1 and 2, the blades 11 of the oscillation chamber 2 have different lengths, wherein this length continuously increases so that the shortest blade 11 is located the closest to the combustion chamber 6 location, meant at blade 11 arrangement in the direction R of the rotor rotation. On the contrary, the blade 11 located the closest to the exhaust manifold 9 is then the longest of all. These blades 11 are solid and tightly connected with the inner surface of the upper part 19 of the housing 3, with which they have the same inclination angle. The distances between the location of individual blades 11 are the same, along the entire length of the oscillation chamber 2. The blades 11 are then diverted from the impeller wheel 13, thus are inclined always in the direction R of the rotation of this impeller wheel 13. In areas, where the inner expansion chambers 10 and the outer expansion chambers 12 are located against each other, an alternating flow of expanded gases between the chambers 10, 12 occurs, which results in a gradual transmission of the thermal and kinetic energy without significant oscillatory effects occurring at the beginnings of each expansion.

In the same example, the invention embodiment of the blade 11 of the oscillation chamber 2 and the impeller blades 5 of the impeller wheel 13 are so long that they never touch in any working moment of the combustion engine 1. The distance between the blades 11 and impeller blades 5 in the point of the shortest mutual distance is in order of pm.

According to the example of the invention embodiment depicted in Fig. 1, the fuel mixture inlet 8 consists of a compressor 14 which presses the supplied air-and-fuel mixture and injects the resulting compressed fuel mixture using an injection nozzle 15 to the combustion chamber 6 where it is ignited. From here, the combusted fuel mixture expands to the housing 3 of the rotary combustion engine 1.

According to the invention embodiment depicted in Fig. 2, a lubrication chamber 17 provided with an opening 18 for the inlet and outlet of the pressure lubricant is located between the impeller wheel 13 and the housing 3. To prevent the contact of the fuel and the combusting fuel mixture, the lubrication chamber 17 is provided with a seal 16.

Industrial Applicability

The rotary combustion engine finds its use in a wide range of motion equipments where the combustion engine is used as a torque generator.

List of reference signs used in the drawings

1 rotary combustion engine

2 oscillation chamber

3 housing

4 main rotary shaft

5 impeller blade

6 combustion chamber

7 spark plug

8 fuel mixture inlet

9 exhaust manifold

10 inner expansion chamber

11 blade

12 outer expansion chamber

13 impeller wheel

14 compressor

15 injection nozzle

16 sealing

17 lubrication chamber

18 opening

19 upper housing part

20 bearing R direction