JP2002227655A - High efficiency rotary engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high efficiency rotary engine, small-sized, lightweight, having a high output, and extremely low in fuel consumption and in environmental pollution. SOLUTION: In this high efficiency rotary engine, a rotary piston 28 is housed in an operation chamber 16 having a suction compression chamber 12 and an expansion exhaust chamber 14, and a circular high pressure chamber 72 is formed concentrically with the operation chamber 16. A timing rotor 74 is housed rotatably in the high pressure chamber 72. The main combustion chamber 84 of the timing rotor 74 is periodically and sequentially communicated with the suction compression chamber 12 and the expansion exhaust chamber 14. A homogeneous extremely lean fuel mixture is introduced into the main combustion chamber 84, a fuel is injected thereinto, and the resultant mixture is ignited as an ignition core to generate an explosive combustion gas. The generated combustion gas is injected from the combustion chamber 84 into the exhaust chamber 14 to generate a motive power for the rotary piston 28. Thereby, ultra-low environmental pollution and fuel consumption, and high output are materialized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine, and more particularly to a rotary engine.

[0002]

2. Description of the Related Art Depletion of petroleum resources, air pollution by automobiles, ships and aircraft and global warming have become serious problems, and urgent countermeasures are desired. for that reason,
Research and development of clean next-generation power has become active in each country,
As effective countermeasures, a rotary engine and a homogeneous lean premixed combustion system have been proposed.

[0003] US Patent No. 5,305,721 proposes a Wankel rotary engine. In this engine, when the apex seal straddles the spark plug, the fuel injection nozzle, and the intake / exhaust port, the gas blows through, so the harmful components in the exhaust gas increase and the fuel efficiency is remarkably poor.

US Pat. No. 5,755,197 proposes a rotary engine in which a rotary piston is rotatably housed in a working chamber having a suction compression chamber and an expansion / exhaust chamber partitioned by a partition member. In this rotary engine, a structure is proposed in which a combustion chamber is formed radially outside the working chamber, and a plurality of movable saddle seals and a rotary valve member respectively engaging with the movable saddle seal are arranged between the combustion chamber and the working chamber. Have been. In this structure, since the airtightness and lubricity between the seal tip and the rotary piston and between the rotary valve and the saddle seal are extremely poor, the output efficiency of the engine cannot be increased. Further, since a large number of connecting members are required for driving the rotary valve, the structure of the engine is complicated, and it is difficult to reduce the size and weight of the engine. Further, with this structure, it is not possible to increase the limit rotational speed of the engine to increase the output.

US Pat. No. 5,979,395 proposes an ultra-lean premixed compression ignition rotary engine. In this engine, the rotary piston is provided with a plurality of movable vanes, and the intake piston is compressed by changing the volume of a suction compression space between adjacent vanes while sliding on the inner peripheral surface of the working chamber. Yes. In this structure, since the maximum capacity of the suction compression space is small, the engine size is inevitably increased in order to increase the output of the engine. Therefore, high output cannot be obtained with a small and lightweight engine. Furthermore, even though the movable vane of the rotary piston is continuously and directly exposed to the high-temperature, high-pressure combustion gas, the lubricating property between the movable vane and the working chamber is extremely poor. High output cannot be obtained. Moreover, in the above structure, the super-lean premixed gas is introduced into the combustion stagnation chamber to cause compression ignition, but the vane slot of the rotary piston is adjacent to the combustion stagnation chamber at the time of maximum compression of the air / fuel mixture. At this time, since a part of the compressed air-fuel mixture leaks into the vane slot, the pressure of the compressed air-fuel mixture is lowered and the temperature is lowered, so that the self-ignition of the extremely lean air-fuel mixture becomes difficult. In this case, knocking or misfire occurs, and stable operation of the engine becomes difficult.

[0006]

As described above, the conventional rotary engine firstly provides a high-efficiency rotary engine of small size, light weight, ultra-low pollution and ultra-low fuel consumption because the engine structure is complicated. Can not do. Second, since it is difficult to obtain a high compression ratio with the conventional rotary engine, it is impossible to stably ignite the ultra-lean premixed gas.

An object of the present invention is to solve the above problems and to provide a small, lightweight, high-output, ultra-low-pollution, ultra-low-fuel-efficiency rotary engine.

Another object of the present invention is to provide a homogeneous ultra-lean mixed compression ignition (Homogeneous Charged comp).
response ignition) (hereinafter, HCCI
Called. ) Type high-efficiency rotary engine.

[0009]

In the high efficiency rotary engine according to the first aspect of the present invention, a rotary piston is rotatably housed in a working chamber of a rotor housing, and a timing rotor is provided in a circular high-pressure chamber formed adjacent to the working chamber. Is rotatably housed, the main combustion chamber is arranged in the timing rotor, and the timing rotor is synchronized with the rotary piston, thereby periodically communicating the main combustion chamber with the working chamber to introduce high-pressure air into the main combustion chamber. Fuel is injected into high-pressure air to generate high-temperature, high-pressure combustion gas, which is returned to the working chamber to generate power in the rotary piston.

In the high-efficiency rotary piston according to the second aspect of the present invention, a working chamber including a suction compression chamber and an expansion / exhaust chamber is formed in a rotor housing, and a fuel injection nozzle is arranged in the suction compression chamber to form a rotary piston in the working chamber. A rotatable housing, a circular high-pressure chamber is formed adjacent to the working chamber, and a timing rotor having a main combustion chamber is rotatably stored in the circular high-pressure chamber, and is adjacent to the circular high-pressure chamber near the compression top dead center. The ignition means is arranged.

[0011]

According to the high-efficiency rotary piston of the first aspect of the present invention, the high-temperature and high-pressure intake air sucked and compressed in the working chamber is periodically introduced into the main combustion chamber of the timing rotor, where fuel is injected into the intake air and ignited. By generating high-temperature and high-pressure combustion gas and then ejecting the combustion gas from the main combustion chamber to the working chamber to generate power on the rotary piston, the engine can be made smaller, lighter, and more powerful. It is.

According to the high-efficiency rotary piston of the second aspect of the present invention, a part of fuel is injected into the suction compression chamber, and the rotary piston mixes intake air and fuel with stirring to generate a uniform ultra-lean premixed gas. Near the top dead center, the homogeneous ultra-lean premix is introduced into the main combustion chamber of the timing rotor, and then additional fuel is injected into the homogeneous ultra-lean premix to ignite to generate high-temperature, high-pressure combustion gas. By circulating the combustion gas from the combustion chamber to the expansion and exhaust chamber and generating power in the rotary piston, it promotes stable ignition of the homogeneous lean premixed gas to achieve both ultra-low pollution and ultra-low fuel consumption. It was done.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A high efficiency rotary engine according to a preferred embodiment of the present invention will be described below with reference to the drawings. 1 and 2, a high-efficiency rotary engine 10 includes an output shaft 11 having a lubricating oil passage 11a.
Suction compression chamber 12 formed symmetrically with respect to the center line of
A rotor housing 18 having a round working chamber 16 including an expansion / exhaust chamber 14, and a front side plate 20.
, Intermediate side plates 22 and 24, oil sump 26
And these are connected to each other by a plurality of bolts. A rotary piston 28 is connected to the output shaft 11 and is rotatably housed in the working chamber 16. As shown in FIGS. 2 and 3, the rotary piston 28 has a major axis and a minor axis. The major axis extends from the minor axis at an acute angle β in the major axis direction at an acute angle β, and extends rearward therefrom. An arc-shaped piston head 32 having an acute angle α approximating the curvature of the working chamber 16. The rotary piston 28 includes an apex seal 34 for improving airtightness and obtaining a high compression ratio, and a side seal 36 extending from the apex seal 34 on a side wall of the rotary piston 28. The apex seal 34 is slidably accommodated in a slide groove 32 a formed at the front edge of the piston head 32 so as to extend in the axial direction, and has an arc-shaped slide having a curvature similar to the inner peripheral surface of the working chamber 16. Moving part 34a
And a side seal holding portion 34 formed at an end of the apex seal 34 and holding the side seal end 36a.
b, and a lubricating oil storage portion 34c. The rotary piston 28 has an oil supply hole 38 extending in the radial direction, and supplies the lubricating oil into the lubricating oil storage portion 34c. The lubricating oil is uniformly supplied to the sliding surface 34a from the side surface of the apex seal 34, and at the same time, the lubricating oil is supplied to the side seal 36 from an oil spray hole described later. Therefore, the lubrication and cooling of the rotary piston 28 are smoothly performed and the compression ratio and the durability are improved. At the same time, the maximum engine speed is increased from 10,000 to 20,000 to increase the output. realizable.

Returning to FIGS. 1 and 2, the rotor housing 1 will be described.
8 has slide grooves 40 and 42 formed at positions symmetrical with respect to the center line of the output shaft 11, and accommodates radially slidable partition members 44 and 46, respectively. The partition member 44 includes an outer slide 44a, an inner slide 44b, springs 44c and 44d, and a rolling roller 44e rotatably supported by the inner slide 44b.
And oil passage holes 44f and 44g. Similarly, the partition member 46 includes an outer slide 46a, an inner slide 46b, springs 46c and 46d, and rolling rollers 46e.
And oil passage heights 46f and 46g. Grease or other lubricant is filled in the outer slides 44a and 46a from a cap (not shown). Further, the rotor housing 18 has an intake port 48 and an exhaust port 50 formed in the intake compression chamber 12 and the expansion / exhaust chamber 14, respectively.
With. The intake port 48 opens near the bottom dead center of the compression. An exhaust gas recirculation device (EGR) 52 is connected between the intake port 48 and the exhaust port 50, and a part of the exhaust gas is flow-adjusted by the control valve 54 so that the intake port 48
Refluxed. A primary fuel injection nozzle 56 is arranged adjacent to the intake port 48, and a part F1 of fuel is injected to a wall surface of the piston 28 during a suction compression process of the rotary piston 28. At this time, the spray colliding with the wall surface of the piston 28 is refined and partially vaporized, and is further uniformly stirred and mixed with the intake air and the recirculated exhaust gas as the piston 28 moves further, further promoting the vaporization of the spray. As a result, a uniform ultra-lean premixture is generated. Near the compression top dead center, that is, adjacent to the partition member 44, the rotor housing 18 has an air-fuel mixture outlet groove 58 extending in the axial direction, and further, near the compression top dead center, that is, the partition member 44.
Is provided with a combustion gas introduction groove 60 having an arcuate cross section adjacent to. The cooling jacket 62 includes a plurality of fins 64 a formed at appropriate intervals so as to extend in the axial direction on the outer periphery of the working chamber 16, communication holes 66 alternately formed in the fins 64 a, and an external device such as a radiator (not shown). A coolant inlet 68 communicating with the cooling device, and a coolant outlet 70
And the arcuate communication groove member 7 arranged on the side of the partition member 44
2 is provided.

1, 2, and 4, a circular high-pressure chamber 72 is formed in the intermediate side plate 22 adjacent to and concentric with the working chamber 16, and the high-pressure chamber 72 is mounted on the intermediate side plate 22. Sealed by the intermediate side plate 24. A timing rotor 74 is connected to the output shaft 11 concentrically with the rotary piston 28.
It is rotatably housed in 2. The timing rotor 74 is symmetrically arranged and a pair of apex seals 76 and 78 sliding on the inner peripheral surface of the high pressure chamber 72 and the apex seal 7
A circular side seal 80 disposed in contact with the bottom surfaces of the high pressure chambers 6 and 78 and sliding on the side wall of the high pressure chamber 72. As is clear from FIGS. 2 and 4, the high-pressure chamber 72 communicates with the air-fuel mixture outlet groove 58 and the combustion gas inlet groove 60 of the working chamber 16. The timing rotor 74 includes a pair of contrasting arc-shaped valve portions 82 for periodically opening and closing the air-fuel mixture outlet groove 58 and the combustion gas inlet groove 60, and a pair of main combustion chambers 84 formed therebetween. An annular ring 86 provided and an oil supply cavity 88 are provided. The annular ring 86 has an oil supply hole 86a extending radially to supply lubricating oil to the apex seal 76. As described later, the lubricating oil sprayed into the cavity 88 receives the side surfaces of the apex seals 76 and 78 from the oil supply hole 86a. , Is forcibly supplied to the inner peripheral surface of the high-pressure chamber 72 by centrifugal force, and very good cooling and lubrication are performed. The main combustion chamber 84 is located just before the compression top dead center of the rotary piston 28 and the mixture outlet groove 5
Combustion gas is supplied to the combustion gas introduction groove 60 when the rotary piston 28 slightly passes the compression top dead center when the rotary piston 28 slightly passes through the compression top dead center. And a combustion gas discharge groove 92 for performing the operation. In the intermediate side plate 22, a small hole 94 communicating with the high-pressure chamber 72 near the compression top dead center and a sub-chamber including a spiral chamber 96 are formed. The spiral chamber 96 has a volume of 70% of the total compression volume, and the main combustion chamber 8 of the timing rotor 74
When the leading edge 90 of the main combustion chamber 8 passes through the small hole 94, the main combustion chamber 8
The super-lean mixture 4 flows into the swirling chamber 96 in a swirling manner.
The piston head 3 of the rotary piston 28 during the compression process
When the trailing edge 32b of the second fuel cell 2 passes the rolling roller 44e, the secondary fuel injection nozzle 9
8, the remaining fuel F2 is injected. At this time, a part of the fuel burns in the swirl chamber 96, and the high-temperature and high-pressure combustion gas is ejected together with the fuel from the small holes 94 into the main combustion chamber 84, where it mixes with a new uniform ultra-lean mixture to form a secondary gas. Self-ignition with fuel as nucleus, complete combustion instantaneously. For this reason,
Exhaust gas in a so-called zero emission state, which contains almost no harmful components such as HC, CO, NOx, black smoke and soot, is emitted. The high-temperature and high-pressure combustion gas in the main combustion chamber 84 passes from the combustion gas introduction groove 60 through the discharge groove 92 to the expansion exhaust chamber 1.
4 is supplied to the minute space between the rolling roller 44e and the rear edge 32b of the rotary piston 28, and drives the piston 28 to generate power on the output shaft 11. In order to make the start of the rotary engine 10 good, a heating plug 100 that glows the nichrome wire electrically is provided in the spiral chamber 96 to preheat the ultra-lean mixture before the start. The heating plug 100 may further heat the high-temperature homogeneous premixture flowing into the sub-chamber 96 to promote self-ignition of the mixture. In this case, 2
The primary fuel injection nozzle 98 is omitted and the primary fuel injection nozzle 5 is omitted.
6 may be modified to inject all fuel. FIG.
As apparent from FIGS. 4 and 5, the combustion gas introduction groove 60 extends in the rotation direction of the rotary piston 28 at a predetermined rotation angle, and enters the expansion exhaust chamber 14 within a relatively wide rotation angle range. Is designed to prolong the combustion gas supply period.

Returning to FIG. 1, lubricating oil / cooling oil 102 is stored in cylindrical oil reservoir 26. Oil 10
2 is cooled externally via port 104 or is replaced with a new one. Oil 102 is the rotary engine 10
Lubrication of stationary parts, bearings and seals in various parts of
And cooling to reduce metal expansion and wear. For this reason, the engine housing and the rotary piston can be made of an aluminum alloy, which has the effect of reducing the moment of inertia of the piston and improving the acceleration and deceleration of the engine. The output shaft 11 has a main oil passage 11a and a plurality of radially extending oil spray holes 11c, 11d, 11e, 11f. Output shaft 1
1 is rotatably supported by bearings 106, 108 and 110 supported by a front side plate 20, an intermediate side plate 24 and an oil reservoir 26, respectively. The output shaft 11 extends into the oil sump 26 and is mounted on an outer wall of the oil sump 26 and a first extension 11g for driving the first gear 112.
6 (FIG. 2) and the secondary fuel injection nozzle 98 (FIG. 4)
Next, a second extension 11h for driving a fuel injection pump 114 for supplying the secondary fuel is provided. First gear 1
Reference numeral 12 drives an oil pump 118 via a second gear 116. The oil 102 is supplied under pressure to an oil chamber 124 formed on the outer periphery of the output shaft 11 through an oil communication hole 122 of the oil pump 118 through a pipe 120 and a front side plate 20. Next, the oil is supplied to each part of the seal via the oil spray holes 11c, 11d, 11e and 11f to cool and lubricate them. The remaining lubricating oil is returned to the oil reservoir 26 via the oil return hole 25 of the intermediate side plate 24. In the oil sump 26, a rotation angle sensor 126 is mounted on the intermediate side plate 24 near the outer periphery of the first gear 112, detects the rotation angle of the output shaft 11, and sends a rotary piston to a control unit (not shown). A rotation angle signal corresponding to the rotation angle of 28 is output. The control unit periodically opens fuel injection valves (not shown) in response to the rotation angle signal to sequentially open the primary and secondary fuel injection nozzles 5.
Primary and secondary fuels are injected into the suction compression chamber 12 and the volute chamber 96 from 6, 98, respectively.

Hereinafter, the operation of the high-efficiency rotary engine 10 will be described in detail. 2, 4, and 5, when the rotary piston 28 rotates counterclockwise, supply air including air and recirculated exhaust gas is sucked from the intake port 48. At this time, a part of the fuel is injected from the primary fuel injection nozzle 56 to the wall surface of the rotary piston 28. The fuel spray is partially vaporized by the high-temperature wall of the piston 28 and mixed with the supply air by stirring to produce a uniform ultra-lean mixture in the suction compression chamber 12. This mixture is compressed by the piston head 32. At this time, since the air-fuel mixture outlet groove 58 is closed by the valve portion 82 of the timing rotor 74,
The uniform ultra-lean mixture is compressed in the suction compression chamber 12. In FIG. 4, when the piston head 32 reaches the vicinity of the compression top dead center, the leading edge 90 of the timing rotor 74 passes through the air-fuel mixture outlet groove 58, and at this time, the main combustion chamber 84 communicates with the suction compression chamber 12. A homogeneous ultra-lean mixture is introduced. Next, the uniform ultra-lean mixture enters the swirling chamber 96 through the small holes 94 in a swirling manner. When the piston head 32 further moves to the position shown in FIG. 5, that is, immediately before the combustion gas discharge 92 of the timing rotor 28 passes through the partition member 44, the secondary fuel F2 is injected into the sub chamber 96. At this time,
A part of the secondary fuel and the ultra-lean mixture is ignited and burned to increase the pressure, and the high-temperature gas is ejected together with the secondary fuel and the ultra-lean mixture into the main combustion chamber 84, where a new ultra-lean mixture is formed. Mixing and complete combustion are performed, and clean combustion gas of high temperature and high pressure is generated. The combustion gas is ejected between the support portion 32b of the piston head 32 and the rolling roller 44e through the combustion gas discharge groove 92 and the combustion gas introduction groove 60 of the timing rotor 74 to drive the rotary piston 28 at a high pressure and output. Power is generated on the shaft 11.

The above-described high-efficiency rotary engine 10 has the following advantages over conventional gasoline engines and diesel engines. 1) Simple structure, small size, light weight, high output and low vibration. 2) Since no valve mechanism is required, the number of parts can be significantly reduced and the engine structure can be made compact. 3) It is possible to obtain a high output by raising the limit of the maximum number of revolutions of the engine to about 10,000 to 20,000 rpm. 4) Since the suction compression step and the expansion / extraction step are performed simultaneously by one rotary piston, the performance of the engine can be improved. 5) Since the rotation unevenness of the engine is small, the flywheel can be reduced in size, and the engine itself can be reduced in weight. 6) Since the rotary piston can reliably perform the suction action and the exhaust action, even if the engine speed increases, part of the exhaust does not remain or flow into the suction side, and no misfire or knocking occurs. 7) At the time of exhaust, a part of the air-fuel mixture is not discharged together with the exhaust, so that fuel is not uneconomical. 8) The fuel is injected into the suction compression chamber and vaporized, agitated and mixed by the rotary piston, so that a uniform ultra-lean mixture is efficiently generated, and self-ignition is promoted to enable complete combustion, thereby achieving zero emission and low emission. Make fuel efficiency compatible. 9) Since the rotary piston and the timing rotor have a structure excellent in airtightness and lubricity, a high compression ratio of the engine can be obtained, and the durability of the engine is greatly improved. 10) An ultra-low-pollution, ultra-low-fuel-efficiency, high-efficiency rotary engine that could not be put to practical use conventionally can be realized.

In the above embodiment, the high efficiency rotary engine of the present invention has been described as a diesel type.
A gasoline engine may be provided by arranging a spark plug in the sub chamber. Further, the rotary engine may have a multi-stage (multi-cylinder) structure. A supercharger is connected in parallel with the exhaust gas recirculation device, and an intercooler is provided for this.
The supercharging amount may be controlled according to the engine load. Further, the primary and secondary fuels may be the same or different types. Note that a heat-resistant and highly durable seal member may be directly slid on the rotary piston instead of the rolling roller of the partition member.

As apparent from the above, according to the present invention, a breakthrough is caused in the thermal efficiency of the engine with an extremely simple structure, and high reliability, low cost, ultra low fuel consumption and ultra low pollution are achieved. It is feasible to provide a high-efficiency rotary engine that achieves this, and it can be expected to make a significant contribution to global environmental measures.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a high-efficiency rotary engine according to a preferred embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 shows a partially enlarged view of the rotary piston of FIG.

FIG. 4 is a sectional view taken along line IV-IV of FIG.

FIG. 5 shows a relationship diagram between the rotary piston of FIG. 1, a timing rotor, and a high-pressure chamber.

[Explanation of symbols]

Reference Signs List 10 rotary engine, 11 output shaft, 12 suction / compression chamber, 14 expansion / exhaust chamber, 16 working chamber, 18 rotor housing, 28 rotary piston, 48 intake port, 50 exhaust port, 56 primary fuel injection nozzle, 5
8 Mixture outlet groove, 60 combustion gas introduction groove, 72 high pressure chamber, 74 timing rotor, 96 sub chamber, 98 secondary combustion gas injection nozzle, 100 heating plug, 114 fuel injection pump, 118 oil pump

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02B 53/02 F02B 53/02 A 53/04 53/04 V 53/06 53/06 Z 53/10 53 / 10 B 55/02 55/02 C 55/14 55/14 D EF

Claims (9)

[Claims] A rotor housing having a working chamber having a suction compression chamber and an expansion / exhaust chamber; a rotary piston connected to an output shaft and rotatably housed in the working chamber; A circular high-pressure chamber formed concentrically in the rotor housing; concentrically connected to the rotary piston and rotatably housed in the circular high-pressure chamber; A high-efficiency rotary engine comprising: a timing rotor having a main combustion chamber that sequentially opens; and a fuel supply unit that supplies fuel to at least one of the suction compression chamber and the main combustion chamber. 2. The high-efficiency rotary engine according to claim 1, further comprising a pair of movable partition members for partitioning the working chamber into a suction compression chamber and an expansion / exhaust chamber while sliding on the rotary piston. 3. The suction compressor according to claim 1, wherein the suction compression chamber and the expansion / exhaust chamber each have an outlet groove and a combustion gas inlet groove communicating with the circular high pressure chamber near the compression top dead center, and the timing rotor is periodically output. High-efficiency rotary engine that opens and closes the groove and the combustion gas introduction groove sequentially. 4. The fuel cell according to claim 1, further comprising a small hole communicating with the circular high-pressure chamber near the compression top dead center, and a sub-chamber periodically communicating with the main combustion chamber via the small hole. A high-efficiency rotary engine including a fuel injection nozzle having a supply unit disposed in a sub-chamber. 5. An apex according to claim 1, wherein the rotary piston has an arcuate piston head having a radius of curvature similar to the inner peripheral surface of the working chamber, and an apex disposed on the piston head and in surface contact with the inner peripheral surface of the working chamber. A high-efficiency rotary engine equipped with a seal, a side seal disposed on the side wall of the rotary piston in contact with the apex seal, and an oil supply hole for supplying lubricating oil to the apex seal. 6. A high-speed engine according to claim 5, wherein the timing rotor includes an apex seal disposed adjacent to the main combustion chamber, a side seal adjacent to the apex seal, and an oil supply hole for supplying lubricating oil to the apex seal. Efficient rotary engine. 7. A rotor housing having a working chamber provided with a suction compression chamber and an expansion / exhaust chamber; a fuel injection nozzle opened to the suction compression chamber to inject fuel periodically; and rotatably housed in the working chamber. A rotary piston for stirring and mixing the intake air and the fuel to produce a uniform lean premixed gas; a circular high-pressure chamber formed in the rotor housing adjacent to and concentric with the working chamber; and concentric with the rotary piston A timing rotor having a main combustion chamber which is rotatably housed in a circular high-pressure chamber and is rotatably housed in a circular high-pressure chamber, and which periodically and sequentially communicates with a suction compression chamber and an expansion exhaust chamber near a compression top dead center in synchronization with a rotary piston; An ignition means arranged near the compression top dead center and adjacent to the circular high-pressure chamber for igniting a homogeneous lean premixture introduced into the main combustion chamber. 8. The apparatus according to claim 7, further comprising a small hole communicating with the circular high-pressure chamber near the compression top dead center, and a sub-chamber communicating with the circular high-pressure chamber through the small hole. A high efficiency rotary engine, which is provided with a fuel injection nozzle arranged to periodically inject additional fuel into a homogeneous lean premixture supplied from a main combustion chamber to a sub chamber to ignite the mixture. 9. A high-efficiency rotary engine according to claim 7, wherein the suction compression chamber and the expansion / exhaust chamber have an intake port and an exhaust port, respectively, and further include an exhaust gas recirculation device connected to the intake port and the exhaust port.