WO2018184035A1

WO2018184035A1 - Two-stroke cycle rotary internal combustion engine

Info

Publication number: WO2018184035A1
Application number: PCT/VN2018/000003
Authority: WO
Inventors: Chi Dien NGUYEN
Original assignee: Chi Dien NGUYEN
Priority date: 2017-03-27
Filing date: 2018-03-23
Publication date: 2018-10-04

Abstract

This invention relates to a rotary internal combustion engine that operates in a two-stroke cycle, equipped with a separate lubricating and/or cooling chamber. A rotary internal combustion engine consists of a rotor of which profile is two-lobed epitrochoid line, rotating on an eccentric shaft in a three-lobed engine body and the combination of a rotor and the body forms three working chambers with a phase difference of 120°. The air drawn into from the first chamber is compressed and scavenged into the second chamber through a gas conduit. The second chamber performs the functions of compression, ignition-expansion. The space in the third chamber is independent of the other two chambers, so the lubricant is fed to lubricate and cool the engine.

Description

TWO-STROKE CYCLE ROTARY INTERNAL COMBUSTION ENGINE

The field of the invention

The invention is referred to internal combustion engines, in particular a rotary internal combustion engine that operates on a two-stroke basis.

Technical status of the invention

A rotary Wankel type engine has no reciprocating piston, it in stead operates thanks to a rotating rotor located in the engine block with epitrochoid-shaped contour. Typically, the rotor has three apices and the engine body has two lobes and rotary engines have been researched and put into commercial production. For example, Mazda Motor Corporation. A rotary engine is of some advantages over traditional reciprocating ones such as simplicity, less moving parts, less vibration, and high power density. However, this type of engine still has some limitations. Since all the chambers involved in the engine cycle (intake, compression, ignition-expansion, exhaust) lead to that there is no separate space to perform the lubrication function as in the traditional reciprocating engine, and the solution is that the lubricant is injected directly into the engine's working chamber (see US Patent Application No, 4,765,291 by Noriyuki Kurio_? Hiroshi Yoshimi) so the life of the Wankel engine is not long. And there has been a lot of effort to solve the lubrication problem for the rotary engine.

According to the US Patent Application No. 8,523,546 B2 by Nikolay Shkolnik, Alexander C. Sholnik who proposed an engine with epitrochoid-shaped rotor (originally called the cycloid, see Fig. 1). At the intersection of the two lobes, there are segments for separating and sealing the chambers and at each lobe of the engine body, a combustion chamber is created. The inlet is located at one side and the other side is the outlet. An air intake passage is generated on one side of the rotor and an exhaust passage is formed on the other side of the rotor. When the rotor rotates, each working chamber performs four strokes in full according to Otto/Diesel cycle. During the intake cycle, the air from the outside goes through the inlet and is fed into each working chamber along the air intake passage on the rotor. During the exhaust cycle, the exhaust gas enters the gas passage on the rotor and exits through the outlet. According to the principle, a lobe of the rotor will always perform compression, ignition-expansion and the remaining is always in charge of the function of exhaust, intake for all chambers. The combustible gas is exposed to only one part of the rotor, which causes the temperature of this part to be always higher than that of the rest. While equipping a rotor with a cooling system is difficult because of its high rotation speed, which reduces the life of the motor; And since all the chambers are involved in the engine cycle, the problem is the same as the Wankel engine mentioned above. In order to solve the above problems, water is used to pump into chambers for purposes of cooling, lubricating and sealing for the combustion chambers. However, the lubricating ability of water cannot be as good as the lobricant is. Moreover, in addition to fuel the engine needs to have water supply system attached that will make loss of compactness and be not convenient to use. According to US Patent Application No. 2014/0209056 by Nikolay Shkolnik, Alexander C. Sholnik, Alex Lyubomirskiy whose proposal was that there be an air-cooling system for rotary engine with the same configuration and some improvements such as the use of a single chamber in a lobe for air passing through and/or air passing through grooves on the rotor for cooling purposes, the remaining chambers are fitted with additional valves to fully perform four strokes of the Otto/Diesel cycle. This design solves the problem of cooling the engine but increases the engine's structure by requiring additional valves to open/close the chambers. Therefore, it is not yet possible to solve the problem of lubrication for the engine.

In traditional two-stroke engines, the crankcase is used for scavenge purpose, the outlet and blowing gateare located on the same cylinder, performing round or horizontal scavenge, resulting in a symmetric crank angle and there is occurence of air leakage (when the blowing gatecloses and the outlet is still open) causes a loss of new intake air. For two-stroke engines that use the crankcase for air intake, there will be no complete lubrication system as the four-stroke engines have, and the lubricant is mixed with fuel at appropriate proportions. This lubrication method consumes a lot of lubricant compared to that of the four-stroke engines. Moreover, the lubrication effect is not good and the fuel combustion is badly affected. As a result, it leads to reduced engine performance, poor exhaust quality and reduced engine life and these are some of the reasons why the two-stroke engine is not as popular as the four-stroke engine.

Technical nature of the invention

The purpose ^"of ^~the^~inveWion s^"to propose a rotaryengine whiclrcarrsolve the above-mentioned- problems, having a specialized chamber for lubricating and/or cooling functions, limiting the thermal imbalance on the rotor and it is possible to design symmetric or asymmetric mixing angles, but the engine still has a simple structure.

A rotary internal combustion engine consists of a rotary rotor of which is a two-lobed epitrochoid and the corresponding engine body has three lobes, rotating on the eccentric shaft in the engine body and the piston rings are located at the intersection of the two lobes on the engine body. An inlet is connected to the chamber in the first lobe of the body, and a combustion chamber on the second lobe of the engine body. There is a passage transporting air from the chamber in the first lobe to chamber in the second lobe and a one-way valve is fitted at one end of this passage, one outlet on the side of the body is connected to the chamber in the second lobe of the engine body. With this structure, the engine will have three corresponding working chambers in three lobes of the engine body and the volume of each chamber will be periodically varied by rotation angle of the rotor.

One unique characteristics of the invention is that only the first and second chambers are involved in the engine cycle according to the two-stroke principle. Specifically, the air/mixture enters through the inlet into the first working chamber; The air/mixing are is transferred to the second working chamber, which performs the functions of scavenge and simultaneously air intake again for the second chamber and the exhaust is swept out through the outlet on the side engine body. Thus, the first working chamber performs the functions of air-intake, primary compression and then scavenge for the second working chamber; The second working chamber performs compression, ignition-expansion. Each cycle of the engine crankshaft implements one power stroke. The lobes of the rotor in turn exposed to the combustible gas, which enable to reduce the thermal imbalance on the rotor.

The outlet is opened/closed by the rotor, the countour of the outlet is made up by that of the rotor at different positions corresponding to the opening/closing times according to the design. Therefore, it is possible to design the outlet with different shapes and sizes so that the mixing angle can be symmetrical or asymmetrical, it is possible to design the outlet so that it closes before the closing of the blowing port to eliminate the stage of air leakage.

The lubrication and/or cooling problem for the engine is solved by the working chamber in the third lobe of the engine body, and the space in the third chamber can operate independently of the other two remaining chambers. It is therefore possible to provide the lubricant or coolant directly into this chamber without affecting the combustion of the fuel and the quality of the exhaust gas. Specifically, a gas passage will interconnect the third chamber to the chamber of lubricant, one or more nozzles deliver the lubricant directly to the third chamber and such lubricant is deposited and goes along with the passage and returns to the oil reservoir.

In another embodiment of the invention, essentially the engine structure is equivalent to the above one. However, the gas passage on the engine body is rearranged at one of the side interconnecting the first chamber with the second, during the rotation, the rotor will open/close the blowing port and outlet. This design enables to further simplify the structure of the engine by eliminating the valve on the gas passage.

In further another embodiment of the inventi n^ih^rdeFto^{^} increase^{^}the^capacity of the engine the air blower is used to charge the two working chambers. That is, the first and second chambers operate independently and these two chambers carry out the stage of compression, ignition-expansion while the scavenge is performed by the air blower and each rotation of the engine crankshaft has two power strokes, increasing the power density of the engine. Meanwhile, the third chamber still performs its functions of lubrication and/or cooling. In addition, in another embodiment, the engine capacity can be further increased by using all working chambers carrying out the stages of the compression, ignition-expansion, and the air scavenge is performed by an air blower.

Brief description of the drawings

The invention is implemented by the following preferred embodiments with the accompanying drawings, but not limited to, the embodiments thereof, in which:

Fig. 1 is a cross-sectional drawing of a rotary engine according to a prior art solution;

Fig. 2 is an overview of the engine according to the embodiment of the invention;

Fig. 3 is the assembly drawing of the engine components according to the embodiment of the invention;

Fig. 4 is the cross-sectional drawing of line II— II on Fig. 5 showing the air-scavenging process; Fig. 5 is the cross-sectional drawing of line I-I on Fig. 4 showing the air-scavenging process; Fig. 6 is the drawing of partial cross-section showing the chamber that is involved in the lubricating function;

Fig. 7 is the drawing showing a working cycle of the engine;

Fig. 8 is the drawing showing the front of the engine according to another embodiment of the present invention;

Fig. 9 is a cross-sectional drawing subject to line III— III on Fig. 8 showing the air-scavenging process; Fig. 10 is the drawing showing a working cycle of the engine according to another embodiment of the present invention;

Fig. 11 is the drawing showing the front of the engine according to another embodiment of the present invention;

Fig. 12 is a schematic diagram of the profile of the outlet and/or blowing port; and

Fig. 13 is the drawing showing a crank angle of the engine.

Detailed description of the invention

The rotary engine hereby rotating according to the preferred embodiment of the invention will be described based on the drawings. The term "traditional two-stroke engine" is understood as an engine with a blowing gate and outlet on the same cylinder, and the opening/closing of the two gates is performed by the piston. The term "symmetrical crank angle" is defined as the 2 times of opening and closing of the outlet (or blowing gate) away from the top dead center (TDC) an equal angle of rotation.

Fig. 2 shows the overview of the engine 100 with a simple configuration.

In-Eig.-3, it shows the engine components as an embodiment of the invention. The engine 100 has the rotor 130, of which profile is an epitrochoid line and simple equations in the Cartesian coordinate system are:

x = ecos(a) + Rcos(P)

y = esin(a) + Rsin(P)

In which: e is the eccentricity, that is, the deviation of the rotor axis 130 in comparison with the engine body 120;

Radius R, rotor 130 has a length of 2(R + e).

The embodiment of the invention is a two-lobed epitrochoid corresponding to α/β = 3. The engine body 120 has three lobes with symmetry axis 101, the inner side profile of each lobe touches the periphery of the rotor 130 as the rotor occupies in full the working chamber in this lobe. In fact, there is a need to be a small gap between the inner side of the engine body and the outside of the rotor for tolerance and thermal expansion.

The crankshaft of the engine is made up of two parts 161, 162. Where one end of eccentric shaft 162 is supported by part 161. The crankshaft is supported by two sides 140 and 150. The piston rings on each side of the rotor 130 are always in contact and slide on each side.

As shown in Fig. 4, at each intersection of the two lobes, there are grooves created to engage the piston ring 123 and due to the elastic force, the piston rings 123 are always in contact with the outer of the rotor 130 for dividing and sealing for the working chambers. Inlet 126 on the first lobe, the second combustion chamber 125 on the second lobe and deflecting towards the first lobe, passage 124 communicates the working chamber in the first lobe with combustion chamber 125, valve 112 is returned thanks to spring 113 and opening/closing of passage 124, cap 176 prevents high-pressure gas in the passage 124 from escaping through the gap between the guide bushing and valve 112.

The combination of rotor 130, engine body 120 and two side bodies will form three working chambers A, B and C and the volume of chambers is priodically varied by the rotor's angle rotation. Chamber A carries out the air-intake function and can be called an inlet chamber and its funtion is similar to the crankcase in a traditional two-stroke engine. Chamber B in the second lobe performs the stage of compression, ignition-expansion. Chamber C in the third lobe performs the funtion of lubrication and/or cooling for the engine, which can be called a lubrication chamber. When rotor 130 rotates, the lobes of the rotor will in turn enter/retract out of the working chamber in the lobes in the order of A, B, and C. These three chambers operate in a 120° phase difference of the crank angle (CA). The lateral side 140 has an outlet 142, fitted to communicate with chamber B and the opening/closing process of this outlet is carried out by rotor 130.

Valve 172 is fitted at inlet 126 so that the external air can enter the chamber A and valve 172 is comprised of thin laminations of steel that can be closed/opened by itself due to differential pressure in chamber A with external pressure. Valve 172 is of simple and effective design. In other embodiments, valve 172 may be replaced by another valve such as a valve, rotary valve, etc., which may perform the same function but increase the complexity of the engine.

In Fig. 5, rotor 130 is supported and rotates on bushings 168, rotor shaft is in parallel and away from axis 101 a distance of e. Two ends of the crankshaft are supported and rotate on two rolling bearings 118, 169. Gear 135 are mouhtacl o «iMly^~¾

with posiitoning gear 183 on lateral side 140. Because the radius 2e of gear 135 is limited, it is better that the crankshaft is formed by two parts 161, 162, so that gear 135 can be mounted on the rotor 130. Counterweight 117 in combination with counterweight 170a on the flywheel 170 has an effect of balance on engine 100.

The parts not required to understand about the invention, such as cooling systems, ignition mechanisms, driving belts, etc..., are not shown in the present invention.

The gear ratio between gear 135 and gear 183 is 2:3, the combination of two gears 135, 183 makes the rotor 130 rotate in diverse direction compared to that of the crankshaft (e.g., in the embodiment of the invention, the rotor rotates clockwise and the crankshaft rotates

1

counterclockwise). With each revolution of the crankshaft, rotor 130 rotates - rounds around the crankshaft.

During the power stroke, the total pressure produced by the combustion gas on the rotor 130 is always going through axis 101, the rotor 130 now resembles an lever of which instantaneous fulcrum is the contact position between the two gears 135 and 183, so in addition to positioning for rotor 130, these two gears are also subject to the impact force and when combined with the pressure of combustion gas will cause torque to rotate axis 162. It is better that gear 135 is supported and rotates on axis 162 by bushing 136.

In Fig. 7, it shows a cycle of engine 100, when ω = 0° the volume of chamber B is minimum and this position is the chamber's TDC and can be considered as the TDC of engine 100. The air/mixture is compressed into combustion chamber 125, the fuel has absorbed heat and evaporates, the spark plug 175 ignites and combusts the mixture, initiating the ignition - expanding at chamber B. In fact, the time of ignition will be made early before the TDC. Meanwhile, chamber A is performing an air-intake process, chamber C is reducing the swept volume of air and lubricant along passage 129 back to oil compartment 106. Rotor 130 continues rotating, when ω = 60° chamber B is still in the process of power-generating expansion (or already ended the power stroke in another embodiment), chamber A finishes the process of intake and reaches its maximum volume. In fact, due to the inertia of the intake gas stream, chamber A will be charged with some additional gas. Meanwhile, chamber C is still performing its exhaust and lubrication.

Continuously, when co = 120°, chamber B is still in power stroke process, chamber A is reducing its volume, the pressure in this chamber is greater than that in tube 174 to close the valve 172. The air pressure in chamber A is gradually increasing but chamber B is still in the power stroke, so the pressure of combustion gas influencing on valve 1 12 is still higher than that of gas in chamber A. As a result, valve 112 remains closed, while chamber C with minimum volume may end the process of exhaust and lubrication.

Rotor 130 continues rotating, outlet 142 begins to open, high pressure in chamber B will help push out some of the exhaust gas through outlet 142, the pressure in chamber B decreases rapidly, the gas pressure in passage 124 is sufficient to open valve 112.

When o --4-80°, chambeiB_ reaches_^ its maximum capacity and this position is the bottom dead center (BDC) of chamber B and can be regarded aslhe BDC f^"en^~gtne l 0 outlet4424s openJn_ full. The air compressed from chamber A goes along with passage 124 to combustion chamber 125, the new air will scavenge the exhaust gas in combustion chamber 125 to chamber B, simultaneously pushing the exhaust gas in this chamber toward outlet 142 to escape out of the engine's exhaust pipe 143 (see also Fig. 4-5). For the scavenging process of high efficiency (thorough scavenging of exhaust gas), combustion chamber 125 is designed tangentially to the periphery of chamber B and deflected towards chamber A. Then the new gas flow will scavenge in eddy direction from the outside inwards. The advantage of this design is that the new gas flow from passage 124 overflows to combustion chamber 125 will not directly scavenge into outlet 142 but rather in the perpendicular direction, preferably into combustion chamber 125 which is located adjacent to chamber A. Meanwhile, the volume of chamber C is increasing, the pressure in this chamber decreases to let in gas through tube 129.

Rotor 130 continues rotating, when co = 240°, outlet 142 has been fully closed, the volume of chamber- A reaches a minimum and most of the gas has been pushed to chamber. B, reducing the pressure in chamber A, and the pressure of gas flow at passage 124 is less than the total pressure of the gas in chamber A and the elastic force of spring 113, resulting in repulsion of valve 112 back to closed passage 124, ending the gas scavenging process. In fact, due to the high velocity of gas flow in passage 124, it causes pressure on valve 112, enabling this valve to remain open for a short time. Meanwhile, chamber B is in the process of reducing the volume, chamber C is still in the process of air intake.

Next, when co = 300°, chamber B is in the compression stage, the gas is pushed into combustion chamber 125 while chamber A is performing a new gas charge, chamber C reaches its maximum volume and ends the process of gas charge. Rotor 130 continues rotating, when co = 360° (or 0°) completes a cycle of engine 100, and a new cycle is started as described above. In the new cycle, the lobe entering chamber B is different from the lobe of the previous cycle. Therefore, the rotor's outer side will alternately contact the combustion gas, limiting the temperature imbalance on rotor 130. Engine 100 performs a power stroke corresponding to a crankshaft rotation.

Fig. 8 shows another embodiment of the invention, accordingly engine 200 has blowing gate 251 formed on the side body 250, passage 224 connecting the blowing gate to chamber A. The opening/closing process of blowing gate 224 is carried out by rotor 230. Combustion chamber 225 is made at chamber B on engine body 220, and spark plug 275 is mounted at this combustion chamber. Chamber A plays the role of gas scavenging for chamber B, preferably the scavenging gas flow faces directly into combustion chamber 225 which pushes the exhaust gas outlet 242 (see Fig. 9). With this design, engine 200 may eliminate valve 112. Meanwhile, chamber C still performs its functions of lubrication and/or cooling.

In Fig.10, it shows a working cycle of engine 200, essentially this working cycle is similar to that of engine 100 and the cycle of engine 200 is completed in a crankshaft rotation. The difference is that the closing/opening of blowing gate and outle in engine 200 is executed by rotor 230 and the horizontal scavenging is applied to engine 200.

--Figr- ^14-shows-another_emboiirnen^fjhejnvention, in which the power density of motor 300 is boosted thanks to the engagement of ignition-expansion proceslTby^wcT chambers ^~-A^~and-B:- Specifically, an air blower 390 is added, which performs air scavenging for both chambers A, B. Preferably, the air-scavenging flow in passages 324a, 324b aims directly into combustion chambers 325a, 325b. Each crankshaft revolution of engine 300 performs two times of power generation while chamber C still performs the function of lubrication and/or cooling. Even in the case that there need be an even higher power density, all three chambers A, B and C are designed to participate in the ignition-expanding process and are scavenged by compressor 390, the engine then having three times of power generation corresponding to each crankshaft rotation.

Here, the opening/closing time of outlet 142 in engine 100 is described, it should be noted that this is still true for outlet 242 in engine 200 and the outlet in engine 300. The opening/closing times of the outlet and blowing gate are indicated by angles Di, D₂, etc, and these symbols can be used to express the rotor's periphery at positions corresponding to those angles.

As shown in Fig. 12, the periphery of outlet 142 is defined by the periphery of rotor 130 corresponding to the opening and closing angles of the outlet. Line D₅ (or D determines when to open the outlet, line D₇ (or D₃) determines when to close the outlet, line D₈ is close to the rotor profile when reaching BDC. Outlet 142 of which profile is formed by a combination of three lines D₈, D₅ (or Di) and D₇ (or D₃). In the traditional two-stroke engine, it is the time when the piston travels to BDC, the volume of the crankcase is minimum level so the blowing gate needs to be opened before the BDC. Meanwhile, engine 100 (and both engines 200, 300) reach(es) the BDC then it is required to rotate 60° CA so that the volume of chamber A should be minimum. Therefore, valve 112 (and blowing gate 251) will open later, outlet 142 is preferrably made up of by three lines D₈, Di and D₇. As a result, the crank angle will be asymmetric through line 102, the increased angle of power generation will benefit the engine capacity.

The periphery of blowing gate 251 in engine 200 is defined similarly to outlet 142. However, the opening time of blowing gate 251 is later than that of outlet 242 an angle of 10° ÷ 35° CA and ending after the volume of chamber A reaches the minimum. As shown in Fig. 13, rotor 130 opens outlet 142 when the angle of rotation of the crankshaft ω reaches the value Di (or D₅), after the TDC, the opening time of valve 112 D₂ is later than Di and D₅. The stage from Ό\ (or D₅) to D₂ is the stage of free exhaust. Rotor 130 closes outlet 142 when the rotation angle ω reaches D₇ (or D₃), valve 112 closes when ω reaches the value D₄. The stage from D₂ to D₇ (or D₃) is the stage of forced exhaust, closure angle D₇ (or D₃) is preferably earlier than closure angle D₄ of valve 112. As a result, there is no air leakage stage, and the stage from D₇ (or D₃) to D₄ is the additional intake stage. The power generation process of chamber B can be performed in 110° ÷ 145° CA or more, and may be larger than traditional two-stroke engine (normally 1 10° ÷ 120° CA).

In the traditional two-stroke engine, the efficiency of the process of scavenging-recharging the gas for the working chamber depending on the pressure of the gas during the scavenging process and the higher the pressure is, the higher the high velocity of the gas flow causes and the more effective the scavenging is. (free of exhaust gas, recharge much new gas). However, the pressure in the crankcase (or chamber A) is too high so that it can consume the engine power. It is better that the gas in chamber A needs to be scavenged thorough to chamber B while the pressure in chamber A remains noTtocThigli, byshri^ volume of chamber A, in other words, by shrinking the space inlet 126 and passage 124 (and 224). Back to Fig. 4, apart from valve 172 with small size, there is no other parts in chamber A, which will result in a large ^^{ma A} ratio,

•minA which may reach 2 ÷ 4 or more, and the higher the ratio is, the greater the air volume of being swept to chamber B is so most of air in chamber A is swept into chamber B. Note that this is the geometric compression ratio of chamber A, not the air pressure in chamber A. Actually, valve 112 (or blowing gate 251) opened earlier, so the air pressure was not too high, the maximum pressure in chamber A was only 1.2 ÷ 1.6 atm or more.

Unlike the traditional Wankel engine, the compression ratio is limited to the geometric compression ratio, so it is difficult to obtain a large compression ratio. The geometric compression ratio of engine 100 is determined by the ratio of the maximum volume Vmax of chamber B and the minimum volume V_min of combustion chamber 125 (ε = V_max V_min), the compression ratio ε depends on the volume of combustion chamber 125 so it is possible to design the engine with a large compression ratio (for Diesel-cycle engines) or smaller (for Otto- cycle engines) by changing the volume of combustion chamber 125.

Back to Fig. 5 - 6, it shows a lubrication scheme for engine 100, the lubricant is pumped along conduit 180a on the flange 180, along conduit 162a to lubricate the bushings and bearings, then the lubricant is recirculated to lines 141, 152 to lubricant reservoir 106. Conduit 128 introduces the lubricant into chamber C, lubricating the outer surface of rotor 130, and simultaneously lubricating the rings on both sides of the rotor, the lubricant in chamber C is guided along conduit 129 to lubricant reservoir 106. The lobes of rotor 130 in turn enter chamber C so they are continuously lubricated and cooled. Chamber C can be expanded to contain the lubricant without reservoir 106, and all lubricant is fed to this chamber.

By using at least one separate chamber to perform function of the engine lubrication according to the invention, it is possible to solve the objectives in question. Specifically, compared to conventional two-stroke engines, the engine in the invention has the same lubrication principle as that in four-stroke engines, the first gain achieved is to improve lubrication performance, the second is efficiency of increased cooling capacity for the rotor, the third efficiency is to support sealing ability as the lubricant fills the gaps of the cylinder. Meanwhile, the structure of the engine simply consists of two rotating parts that are rotor and crankshaft so the next efficiency is to reduce the vibration. Moreover, it is possible to design the outlet and blowing gate with asymmetric opening/closing time, so it is possible to optimize the engine stages. Other similar variants may also be made of from this invention.

In the first example, in another embodiment, engine 100 can be equipped with a further outlet ,on side 150 that is similar to outlet 142. At that time, combustion chamber 125 is located in the middle or the outlet, the new air from passage 124 will sweep from the middle of chamber B towards the two outlets.

In the second example, a three-lobe rotor engine incorporating a four-lobe engine body forms four working chambers, the first and third chambers associate with each other and complete a cycle of engine. The air/mixture charged into the first chamber will be swept into the third chamber and the third chamber performs the function of ignition-expansion, the second and forth chamber performs the lubrication cycle.

In the third example, in the general case, an engine consisting of N-lobed rotor, the engine body combines with rotor to form N+l working chambers, at least one of these chambers performs the stages such as: compression, ignition-expansion, air scavenging is performed by an air blower. At that time, the engine may or may not have a chamber that performs a lubrication function. Although the invention has been described in aforementioned embodiments, it is understood that the present invention is not limited to the description or drawings. The degree of this invention must be determined solely by the claims that are not limited to the presentation of the specifications, and the varied variations may be modified by those have skill in the art are not outside the scope of the invention.

Claims

1. A rotary internal combustion engine, including:

a rotor of which profile is two-lobed epitrochoid-shaped;

an engine body that has three areas to receive the abovementioned lobes of the rotor and these three areas are evenly distributed around the symmetry axis of the engine body;

a crankshaft that has an eccentric shaft around which the above rotor rotates;

two side bodies are located on the two sides of the engine body, the combination of these two side bodies with the above mentioned engine body and the rotor forms three working chambers, namely the first chamber, the second chamber and the third chamber;

in which the first chamber is configured to perform the stages of intake, scavenging and the second chamber is configured to perform the stages of compression, ignition-expansion; there is at least one outlet located in at least one of the two side bodies above and this outlet will discharge the air for the said second chamber;

there is one at least inlet located to charge the air for the said first chamber; and

there^~is atieast one-passage locate to-communicate he- first chamberjojhe^ec^nd diamber.

2. The internal combustion engine as mentioned in Point 1, where the said third chamber is configured to receive and circulate the lubricant.

3. The internal combustion engine as mentioned in Point 2, where the apices towards the center of the said engine body are grooved for inserting seals.

4. The rotary internal combustion engine as mentioned in Point 3, where the said crankshaft is formed by two axes in which the said eccentric shaft is formed by the first and second axes; and

the second axis is supported and rotates for one end of the first axis.

5. The rotary internal combustion engine as mentioned in Point 4, where at each of said inlet there is a valve located and this valve only lets the air pass from the outside to the said first chamber.

6. The rotary internal combustion engine as mentioned in Point 5, where there is one combustion chamber located at the said second chamber.

7. The rotary internal combustion engine as mentioned in Point 6, where there is one valve located at each passage and this valve only lets the air from the first chamber to the said second chamber.

8. The rotary internal combustion engine as mentioned in Point, in which the said gas passage is located in the other side of the engine body, it is the side that is not on the same of side with aforesaid outlet. .

9. A rotary internal combustion engine, including:

a rotor of which profile is N-lobed epitrochoid-shaped, in which N > 2;

an engine body that has N+1 areas to receive the abovementioned lobes of the rotor and these areas are evenly distributed around the symmetry axis of the engine body;

a crankshaft that has an eccentric shaft around which the above rotor rotates;

two side bodies are located on the two sides of the engine body, the combination of these two side bodies with the above mentioned engine body and the rotor forms N+1 working chambers, in which there is at least one chamber configured to carry out the stages of compression, ignition-expansion;

an air blower that scavenges the air for the working chambers with the above-mentioned ignition-expansion stage;

there is at least one outlet located in at least one of the two side bodies above and this outlet will discharge the air for each working chamber with the above-mentioned ignition- expansion stage; and

there is at least one blowing gate located in at least one of the two side bodies above, in which each blowing gate faces each of the said outlet, each blowing gate will charge the gas for each of the working chambers with combustion gas. Each of the abovesaid blowing gate is communicated with the air blower.

10. The rotary internal combustion engine as mentioned in Point 9, in which there is at least working chamber configured to receive and circulate the lubricant.