Rotary piston internal combustion engine

Abstract

A rotary piston internal combustion engine includes an engine housing, an output shaft configured to rotate about an axis relative to the engine housing to transfer power to a component to be operated, a rotary piston eccentrically mounted on the output shaft, a first bearing configured to support and promote rotation of the output shaft, and a second bearing configured to support and promote rotation of the rotary piston. And a second bearing configured to support and promote rotation of the rotary piston, the second bearing being sandwiched between the second pair of seals, where the output shaft defines an internal path having a first region allowing a lubricating substance to flow between the first bearing and the second bearing in use.

Description

Technical Field

[0001] The present invention relates to a rotary piston internal combustion engine. More particularly, the present invention relates to a rotary piston internal combustion engine having an arrangement for improving the lubrication efficiency of internal bearings and sliding surfaces. Background Art

[0002] As is well known, a rotary piston internal combustion engine, such as a Wankel engine, comprises an elliptical epicycloidal cavity formed in an engine housing, a rotary piston and an output shaft. The rotary piston has a generally triangular shape with convex curved sides. Three vertex seals are located at the three vertices of the rotary piston. During operation, the vertex seals maintain physical contact with the inner peripheral surface of the cavity, thereby forming three combustion chambers. The cavity is provided with an inlet and an exhaust port, the inlet supplying fuel and / or air mixture to the cavity, and the exhaust port exhausting the exhaust gas into the atmosphere after combustion in the combustion chamber. The combustion of the fuel causes the combustion gases to expand, thereby increasing the pressure in the combustion chamber, which in turn causes the rotary piston to rotate relative to the engine housing. For every rotation of the rotary piston, the output shaft rotates three times. A lubricating substance, such as oil, can be introduced into the engine to prevent overheating and seizure by lubricating moving parts (such as bearings and seals), thereby extending the service life of the engine.

[0003] EP2240671 discloses a known method for lubricating the moving parts of a rotary engine, which discloses a metering pump that provides oil to a cooling circuit. The oil is carried by the circulating cooling or combustion gases to lubricate various components, such as bearings, gears and the internal sliding surfaces of a rotary piston. A certain proportion of the oil then flows out of the rotary piston and returns to the rotary piston through external pipes, a cooling heat exchanger and a pump. The circulating oil can also enter the combustion chamber of the engine as part of the air intake. Therefore, all the oil injected into such an engine will eventually be burned and discharged into the atmosphere.

[0004] One disadvantage of the lubrication system disclosed in EP2240671 is that it consumes a large amount of oil introduced into the engine. TM A 40 BHP rotary engine (made by Advanced Innovative Engineering in Lichfield, UK, whose lubrication system is derived from EP2240671) consumes oil at a rate of about 150 ml / hour. In this engine, the distribution of oil is random, dependent on engine dynamics and system pressure. As a result, oil reaches components that do not need lubrication. Therefore, a large amount of lubricating material is required to ensure that all moving components are adequately lubricated. In addition, the oil may be mixed with impurities, such as carbon deposits from the sliding surfaces of the rotating pistons, which means that since part of the oil may be recirculated, impure oil may be transferred to other components, such as bearings.

[0005] Vehicles or equipment containing such engines may have higher hydrocarbon emissions due to the large amount of oil burned. This means that owners of these vehicles may be subject to fines in countries that have strict policies on vehicle emissions, such as clean air taxes. Due to global warming, many countries may adopt stricter restrictions, which may lead to high carbon emission vehicles being banned in certain countries. In addition, maintenance costs cannot be ignored because a large amount of oil is required to keep these engines running properly. Furthermore, a large capacity oil storage tank may be required to store the required oil, which is not ideal.

[0006] It is a non-exclusive object of the present invention to overcome or at least substantially alleviate one or more of the problems associated with the prior art and / or the problems mentioned above.

[0007] One goal is to maintain lubrication performance while reducing lubricant oil consumption. Summary of the invention

[0008] According to a first aspect of the present invention, there is provided a rotary piston internal combustion engine comprising:

[0009] Engine housing;

[0010] an output shaft configured to rotate about an axis relative to the engine housing for transmitting power to a component to be operated;

[0011] A rotary piston eccentrically mounted on the output shaft;

[0012] a first bearing configured to support and facilitate rotation of the output shaft, the first bearing being sandwiched between a first pair of seals; and

[0013] A second bearing is configured to support and facilitate rotation of the rotary piston, the second bearing being sandwiched between a second pair of seals; wherein the output shaft defines an internal path including a first region for allowing a lubricating substance (such as oil) to flow between the first bearing and the second bearing when in use.

[0014] The rotary piston internal combustion engine can be configured so that the lubricating substance flows from the first bearing to the second bearing.

[0015] Optionally, the internal path includes a second region for allowing lubricating substance to flow between the second bearing and the third bearing in use.

[0016] The rotary piston internal combustion engine may be configured so that the lubricating substance flows from the second bearing to the third bearing.

[0017] Optionally, the output shaft defines a hole extending at least partially along the axis. The rotary piston internal combustion engine may further include a first barrier element. The first barrier element may be located between the first region and the second region in the hole. The first barrier element may be configured to direct the lubricating substance from the first portion to the second bearing.

[0018] Optionally, the first barrier element is configured to prevent the lubricating substance from flowing along the hole and passing through the first barrier element.

[0019] Optionally, the rotary piston internal combustion engine further comprises a second barrier element. The second barrier element may be located in the hole and configured to guide the lubricating substance to flow from the second portion to the third bearing.

[0020] Optionally, the second barrier element is configured to prevent the lubricating substance from flowing along the hole and passing through the second barrier element.

[0021] Optionally, the rotary piston internal combustion engine further comprises a rod located within the bore.

[0022] Optionally, the rod comprises one or both of a first barrier element and a second barrier element.

[0023] Optionally, the rod is biased towards the first bearing. The rod may be biased by a resilient member such as a spring (eg a helical spring). The resilient member may be located within the hole.

[0024] Optionally, a third bearing is configured to support and facilitate rotation of the output shaft.

[0025] Optionally, the third bearing is in fluid communication with the thrust bearing.

[0026] Optionally, the third bearing and the thrust bearing are arranged such that, in use, the lubricating substance moves from the third bearing to the thrust bearing in a direction parallel to the axis.

[0027] Optionally, the thrust bearing comprises a first side and a second side, the second side being spaced apart from the first side along the axis, wherein the first side comprises an inlet for receiving lubricating substance from the third bearing and the second side comprises an outlet for lubricating substance to exit the thrust bearing.

[0028] Optionally, the third bearing is sandwiched between the thrust bearing and the third seal.

[0029] Optionally, the first bearing and / or the third bearing comprises:

[0030] ring;

[0031] a cage located within the ring and mounted coaxially therewith; and

[0032] Rolling elements, wherein the rolling elements are supported relative to the rings by a cage.

[0033] Optionally, the cage defines an aperture extending from an outer surface to an inner surface thereof, wherein the aperture receives at least a portion of the rolling elements.

[0034] Optionally, the ring comprises an inlet for receiving a lubricating substance.

[0035] Optionally, the ring includes a channel extending around its outer surface, the channel being in fluid communication with the inlet.

[0036] Optionally, the inlet is formed in the channel.

[0037] Optionally, the first and / or second pair of seals comprises one or more seals configured to withstand fluid pressures of 300 kPa and above. For example, the seals are configured to withstand pressures of 300 kPa to 10,000 kPa, such as 300 kPa to 1,000 kPa, for example 300 kPa to 500 kPa.

[0038] In one embodiment, the first pair of seals includes a first seal configured to withstand a fluid pressure of 300 kPa and above (e.g., 300 kPa to 10,000 kPa, such as 300 kPa to 1,000 kPa, for example 300 kPa to 500 kPa) and a second seal configured to withstand a fluid pressure of up to 299 kPa (e.g., 50 kPa to 299 kPa).

[0039] In one embodiment, the second pair of seals includes first and second seals configured to withstand a fluid pressure of up to 299 kPa (eg, 50 kPa to 299 kPa).

[0040] Optionally, the second bearing only includes or is completely composed of a ring fixed to the inner circumference of the rotary piston.

[0041] Optionally, the rotary piston internal combustion engine further comprises a lubricating substance reservoir and a pump. The pump may be configured to pump lubricating substance from the lubricating substance reservoir to the first bearing.

[0042] Optionally, the rotary piston internal combustion engine further comprises a rotor cooling system cavity and a lubricating substance reservoir, wherein in use, the lubricating substance reservoir is pressurized by purge gas in the rotor cooling system cavity, causing lubricating substance to flow from the lubricating substance reservoir to the first bearing.

[0043] Optionally, the lubricating substance reservoir is located inside or outside the engine casing.

[0044] Optionally, the rotary piston is of a generally triangular shape with three apex seals. The inner circumference of the engine housing may have a two-leaf cycloid shape. When in use, the apex seals may maintain physical contact with the inner circumference.

[0045] According to a second aspect of the present invention there is provided a vehicle or apparatus comprising a rotary piston internal combustion engine according to the first aspect.

[0046] The vehicle can be a car, motorcycle, aircraft (such as a drone), jet ski, or snowmobile.

[0047] The equipment may be a power tool, such as a chainsaw. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0049] Figure 1a and Figure 1b is a cross-sectional view of the engine showing the different orientations of the rotating piston relative to the engine housing;

[0050] Figure 2 is a perspective view of a rotating piston;

[0051] Figure 3 is a cross-sectional view of the engine section;

[0052] Figure 4 is a perspective view of the output shaft;

[0053] Figure 5 is a perspective view of a rotary piston mounted on an output shaft;

[0054] Figure 6 is a perspective view of the bearing;

[0055] Figure 7 is a cross-sectional view of the engine section;

[0056] Figure 8 is a cross-sectional view of the engine section;

[0057] Fig. 9 is a cross-sectional view of the output shaft;

[0058] Fig.10a and Fig.10b are cross-sectional views of first and second embodiments of the present invention;

[0059] Fig.11 is a cross-sectional view of the engine portion showing the bearings;

[0060] Fig.12 is a schematic diagram of an engine according to a third embodiment of the present invention;

[0061] Fig.13 Schematic diagram of an engine according to a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0062] refer to Figure 1a and1b , shows an engine 1, which includes an engine housing 10, which is configured to accommodate at least one output shaft 12 and a rotary piston 16. The engine housing 10 defines a cavity having an inner peripheral surface 104. The engine housing 10 may have an air inlet 100 and an exhaust port 102. The air inlet 100 may be configured to supply air and / or a fuel mixture into the cavity. The exhaust port 102 may be configured to discharge exhaust gas, for example, to the atmosphere. The inner peripheral surface 104 may have a two-leaf cycloid shape. The rotary piston 16 may have a generally triangular shape. However, those skilled in the art will appreciate that other shapes of the inner peripheral surface 104 (e.g., a cycloid shape of three or more leaves) and the rotary piston 16 are also available without departing from the scope of the present invention. The rotary piston 16 may have a vertex seal 160 at its vertex. There may be one or more vertex seals 160 at each vertex of the rotary piston 16. When used, the vertex seal 160 may be configured to maintain physical contact with the lubricating substance on the inner peripheral surface 104. In some embodiments, the apex seal 160 can be configured to maintain physical contact with the inner peripheral surface 104. A combustion chamber 106 can be formed between the apex seal 160 and the inner peripheral surface 104. During the combustion process, the gases expand, increasing the pressure in the combustion chamber 106. The high-pressure gases move toward the area of ​​larger volume, causing the rotating piston 16 to be driven relative to the engine housing 10.

[0063] refer to Figures 3 to 5 , a rotary piston 16 is eccentrically mounted on the output shaft 12. When the rotary piston 16 is driven, the output shaft 12 also rotates relative to the engine housing 10 about the axis 14. For each rotation of the rotary piston 16, the output shaft 12 rotates three times. Therefore, power can be transmitted to the components that need to be operated, such as wheel axles or rotor blades.

[0064] The first bearing 18 is configured to support and facilitate rotation of the output shaft 12. In use, the first bearing 18 may be located near the first end 12a of the output shaft 12.

[0065] The second bearing 11 is configured to support and facilitate the rotation of the rotary piston 16. In some embodiments, the second bearing 11 may consist of only a ring fixed on the inner circumference 162 of the rotary piston 16.

[0066] The engine 1 may include a third bearing 15, which may be configured to support and facilitate rotation of the output shaft 12. When in use, the third bearing 15 may be located near the second end 12b of the output shaft 12, opposite the first end 12a. The rotary piston 16 may be positioned along the axis 14 between the first bearing 18 and the third bearing 15.

[0067] refer to Figure 6, the first bearing 18 can include a ring 182 and a cage 184. The cage 184 can be located inside the ring 182 and mounted coaxially with the ring 182. The rolling element 186 can be supported relative to the ring 182 by the cage 184. The cage 184 can define an orifice 1840. The orifice 1840 can extend from the outer surface of the cage 184 to the inner surface. The orifice 1840 can be configured to accommodate at least a portion of the rolling element 186. In some embodiments, there can be a plurality of rolling elements 186 and corresponding orifices 1840. When in use, the rolling element (multiple) 186 can be in physical contact with the output shaft 12. The ring 182 can include an inlet 1820 configured to receive a lubricating substance. The ring 182 can include a channel 1822 around its outer surface. The channel 1822 can be in fluid communication with the inlet 1820. For example, the inlet 1820 can be formed in the channel 1822.

[0068] In embodiments including the third bearing 15 , the third bearing 15 may have the same or similar configuration as the first bearing 18 .

[0069] Back to Figure 3 , the first bearing 18 can be clamped between the first pair of seals 180. The first pair of seals 180 may include one or more high-pressure seals configured to withstand fluid pressures of 300kPa and above. One or more high-pressure seals may be configured to withstand fluid pressures of 300kPa to 10,000kPa, for example 300kPa to 1,000kPa, such as 300kPa to 500kPa. For example, one or more high-pressure seals may be multiple (e.g., double) lip high-pressure seals. The first pair of seals may include one or more low-pressure seals configured to withstand fluid pressures of up to 299kPa. One or more low-pressure seals may be configured to withstand fluid pressures of 50kPa to 299kPa. For example, one or more low-pressure seals may be configured to withstand fluid pressures of 100kPa to 299kPa. In some embodiments, the first pair of seals 180 of the present invention may include a high pressure seal 1800 configured to withstand fluid pressures of 300 kPa and above, and a low pressure seal 1802 configured to withstand fluid pressures up to 299 kPa ( Figure 7 ).

[0070] The second bearing 11 may be sandwiched between a second pair of seals 110. The second pair of seals 110 may be low pressure seals configured to withstand fluid pressures up to 299 kPa.

[0071] The third bearing 15 may be sandwiched between a pair of seals. The third bearing 15 may be sandwiched between a third seal 150 and a thrust bearing 17. The third bearing 15 may be in fluid communication with the thrust bearing 17. The third seal 150 may be a low pressure seal configured to withstand a fluid pressure of up to 299 kPa.

[0072] The thrust bearing 17 may be a conventional rotary bearing, such as a ball bearing. The thrust bearing 17 may include a first side 170 and a second side 172 spaced apart from the first side 170. The thrust bearing 17 may include an inlet 1700 and an outlet 1720 ( Figure 7 ).

[0073] refer to Figure 3 , the output shaft 12 defines an internal path 13. In use, the lubricating substance can flow from the first bearing 18 along the first region 130 of the internal path 13 to the second bearing 11. The lubricating substance can flow from the second bearing 11 along the second region 132 of the internal path 13 to the third bearing 15.

[0074] The output shaft 12 may define a bore 120 that extends at least partially along the axis 14 from the first end 12a to the second end 12b.

[0075] In some embodiments, rod 19 can be located within hole 120. Rod 19 can be hollow. Rod 19 can be made of aluminum. Rod 19 can have a first end 190 and a second end 192.

[0076] The rod 19 may include a first barrier element 1200. During use, the first barrier element 1200 may be located between the first region 130 and the second region 132. The first barrier element 1200 blocks the continued flow of lubricating material along the hole 120 by redirecting the flow from the first region 130 to the second bearing 11. As shown, the first barrier element 1200 may be formed by a thickened portion of the rod 19. The first barrier element 1200 may be tapered. However, in some embodiments, the first barrier element 1200 may take other forms, such as a deflection member extending from the rod 19. In some embodiments, the first barrier element 1200 may not constitute a part of the rod 19. For example, the first barrier element 1200 may constitute another component of the engine 1, such as an inner wall or a part of the output shaft 12.

[0077] The rod 19 may include a second barrier element 1202. During use, the second barrier element 1202 may be located between the second region 132 and the second end 12b of the output shaft 12. The second barrier element 1202 blocks the continued flow of lubricating material along the hole 120 by redirecting the flow from the second region 132 to the third bearing 15. As shown, the second barrier element 1202 may be formed by a thickened portion of the rod 19. However, in some embodiments, the second barrier element 1202 may take other forms, such as a deflection member extending from the rod 19. In some embodiments, the second barrier element 1202 may not constitute a part of the rod 19. For example, the second barrier element 1202 may constitute another component of the engine 1, such as an inner wall or a part of the output shaft 12.

[0078] The rod 19 has two key functions. Firstly, the rod 19 includes first and second barrier elements 1200, 1202 which act as a flow divider to ensure that oil is redirected from the bore 120 to the respective second and third bearings 11, 15. Secondly, the presence of the rod 19 reduces the amount of oil required to start the engine. This is because the rod 19 takes up space within the bore 120. In versions where the rod 19 is hollow, this helps improve the overall weight gain, which is particularly advantageous in aerospace applications.

[0079] The rod 19 may be biased toward the first end 12a of the output shaft 12. The rod 19 may be elastically biased by a spring 1206 acting on the second end 192 of the rod 19 ( Figure 7 ). The spring 1206 ensures that the rod 19 maintains the correct position during use. For example, the spring 1206 can compensate for the different thermal expansions of the output shaft 12 and the rod 19.

[0080] The first region 130 and the second region 132 of the inner path 13 will now be further described (refer to Fig. 9 ). The first region 130 may include a first portion 1300, a second portion 1302, and a third portion 1304. The second region 132 may include a first portion 1320, a second portion 1322, and a third portion 1324.

[0081] The first and second portions 1300, 1302, 1320, 1322 are substantially perpendicular to the axis 14 in the respective first and second regions 130, 132. The third portion 1304, 324 is substantially parallel to the axis 14 in the respective first and second regions 130, 132.

[0082] Once the lubricant is delivered to the first bearing 18 (described in detail below), the lubricant may enter the first region 130 through the first portion 1300, flow along the third portion 1304, until redirected to the second portion 1302 by the first barrier element 1200. The lubricant then flows into the second bearing 11, and is then delivered to the first portion 1320 and the third portion 1324 of the second region in sequence, until redirected to the second portion 1322 of the second region by the second barrier element 1202. The lubricant then flows into the third bearing 15 and is discharged through the thrust bearing 17.

[0083] In versions that do not include rod 19, output shaft 12 can include two holes (not shown). A first hole can be drilled into output shaft 12 from first end 12a, and a second hole can be drilled into output shaft 12 from second end 12b. In these versions, first and second portions 1300, 1302 of the first region can be in fluid communication with the first hole. First and second portions 1320, 1322 of the second region can also be in fluid communication with the second hole. First barrier element 1200 can be defined by a portion of output shaft 12 that separates the first hole from the second hole.

[0084] refer to Fig.10a and 10b The engine 1 may further include a lubricating substance reservoir 2 and a pump 4. The lubricating substance reservoir 2 may be located inside the engine housing 10 ( Fig.10a ) or external ( Fig.10b ). refer to Fig.10b The lubricating substance reservoir 2 may have a calibrated sight glass 20 configured to allow a user to determine the level of the lubricating substance. The pump 4 may be configured to pump the lubricating substance from the lubricating substance reservoir 2 to the first bearing 18. In some embodiments of the present disclosure, the pump 4 may be controlled by an engine control unit (ECU). The ECU may be configured to receive relevant information from sensors located in the engine 1. The sensors may include temperature, pressure, level and / or flow sensors. Alternatively, the pump 4 may be manually controlled.

[0085] refer to Fig.11 , the lubricating substance may be supplied to the first bearing 18 through the inlet 108 and the supply passage 1080. The supply passage 1080 may supply the lubricating substance to the passage 1822 of the first bearing 18.

[0086] refer to Fig.12 The engine 1 may further include a metering valve 6. The metering valve 6 may be configured to control the amount of lubricating substance delivered to the inner peripheral surface 104 of the engine housing 10 to provide lubrication to the contact surface of the rotary piston 16 itself.

[0087] refer to Fig.13The engine 1 may further include a self-pressurized air rotor cooling system (SPARCS). The SPARCS may include a rotor cooling system cavity 81.

[0088] refer to Figure 2 , the rotary piston 16 may have a first face 168 and a second face 169. The first face 168 and the second face 169 may be on opposite sides of the rotary piston 16. One or more side seals 166 may be located on the first face 168 and / or the second face 169. The side seals 166 may be located between the apex seals 160.

[0089] Reference Figure 1a and 1b , the combustion gases in the working chamber 106 may bypass the side seal 166 and leak into the passages in the rotating piston 16. These leaked combustion gases are called blowby gases. Blowby gases can enter the rotor cooling system chamber 81 (see Fig.13 ). As a result, the rotor cooling system cavity 81 may be pressurized. In these versions, the lubricating substance reservoir 2 may be pressurized by blowby gases in the rotor cooling system cavity 81 (at Fig.13 Thus, the pure oil in the lubricating substance reservoir 2 may be forced to be delivered to the first bearing 18 (at Fig.13 denoted by arrow B in the figure). Therefore, Fig.12 The pump 4 shown may not be required.

[0090] While it may be necessary to provide a separate supply directly from the lubricating substance reservoir 2 to the engine inner peripheral surface 104, initial testing has shown that sufficient lubricating substance can reach all critical engine components via the internal path of the output shaft 12 so that this is unlikely to be necessary.

[0091] Reference Fig.10a and 10b, the pump 4 pumps the lubricant from the lubricant reservoir 2 through the first bearing 18 to the internal path 13 of the engine housing 10. In one embodiment of the present disclosure, the pump 4 is controlled by an engine control unit (ECU). Sensors located in the engine 1 send relevant information about the physical state of the engine 1 (e.g., oil level, pressure, temperature, and flow rate) to the ECU. The relevant information can be sent at predetermined time intervals. The ECU then adjusts the flow rate of the lubricant provided to the first bearing 18 based on the relevant information to compensate for any changes in the physical properties of the lubricant, such as viscosity. For example, at higher temperatures, the viscosity of the lubricant in the engine 1 may decrease, so a lower flow rate is required to achieve adequate lubrication. The ECU ensures that the optimal amount of lubricant is provided to the engine, thereby limiting the waste of lubricant. In another embodiment of the present disclosure, the pump 4 is manually controlled. The user can determine the amount of lubricant consumed over a period of time by observing the change in the lubricant level on the calibrated window glass 20 on the lubricant reservoir 2. Alternatively, the sensor installed in the engine 1 provides the user with relevant information (e.g., the remaining lubricant volume, pressure, temperature, and flow rate) through a user interface. Subsequently, the user can change the flow rate of the lubricant by adjusting the power of the pump 4 accordingly.

[0092] In some embodiments, particularly with reference to Figure 6 and 11 , the lubricating substance is pumped to the inlet 108 of the engine housing 10. The lubricating substance then flows along the supply channel 1080 until it reaches the channel 1822 of the first bearing 18. The lubricating substance flows along the channel 1822 until it enters the inlet 1820. The lubricating substance then lubricates the contact surface between the rolling element 186 and the output shaft 12. As the output shaft 12 rotates, the rolling element 186 also rotates in the same direction. The lubricating substance is further distributed between the contact surfaces. Therefore, the first bearing 18 reduces the axial vibration of the output shaft 12, ensuring smooth rotation around the axis 14.

[0093] The first pair of seals 180 is used to direct the lubricating substance from the first bearing 18 through the first portion 1300 to the first region 130 of the internal path 13. Similarly, the second pair of seals 110 is used to direct the lubricating substance from the second bearing 11 through the first portion 1320 to the second region 132 of the internal path 13. The third seal 150 is also used to direct the lubricating substance to flow in the third bearing 15 to the inlet on the first side 1700 of the thrust bearing 17. In some embodiments, the third bearing 15 and the thrust bearing 17 are configured to move the lubricating substance in a direction parallel to the axis 14 until it is received by the thrust bearing 17. The lubricating substance then lubricates the thrust bearing 17 and flows out of the outlet on the second side 1720 of the thrust bearing 17.

[0094] The following advantages of the engine 1 are apparent.

[0095] Firstly, the engine 1 significantly reduces the consumption of lubricating substances compared to the prior art. This is because the lubricating substances are directed specifically to the locations where lubrication is required, namely the first bearing 18, the second bearing 11 and the third bearing 15, rather than flowing to components that require little or no lubrication. This controlled supply of lubricating substances into the engine 1 ensures minimal waste. The engine according to the present invention has been shown to consume about 10 ml of lubricating oil per hour, while the consumption rate of the prior art is about 150 ml / hour. Therefore, compared to the prior art, the engine in the present disclosure is lower in carbon emissions and is therefore more environmentally friendly than the engines of the prior art.

[0096] Secondly, because the lubricating substance is first delivered specifically to these locations, the bearings receive pure or substantially pure oil. The lubricating substance does not mix with impurities inside the engine 1, such as impurities from the sliding surfaces of the rotating pistons, before contacting the bearings. This can extend the service life of these moving parts.

[0097] Third, since the volume of lubricating substance required is significantly reduced, the overall size and / or weight of the vehicle or equipment can be reduced, for example by reducing the volume of the lubricating substance reservoir. This advantage is particularly advantageous when the engine is used in an aircraft (such as a drone).

[0098] Fourth, providing a controlled flow path for the lubricant simplifies the required control measures - there is only one inlet and one outlet for the lubricant. These simplified control measures can enable the ECU to adopt more accurate control, further improving the reliability of the engine 1.

[0099] Those skilled in the art will readily appreciate that additional bearings may be provided that are configured to support and facilitate the rotation of the output shaft 12. In addition, the engine 1 may include one or more additional rotary pistons 16. As will be appreciated by those skilled in the art, these rotary pistons may include associated respective bearings.

[0100] Furthermore, although the embodiment illustrated in the figures shows lubricating material being delivered from the lubricating material reservoir 2 to the first bearing 18, those skilled in the art will appreciate that the lubricating material may alternatively be delivered to any other bearing, such as the second bearing 11 or the third bearing 15, without departing from the scope of the present invention.

[0101] The terms "comprises", "comprising" and their variations used in this specification and claims mean that the specified features, steps or components are included. These terms should not be interpreted to exclude the presence of other features, steps or components.

[0102] The present invention may also broadly include two or more parts, elements, steps, examples and / or features in any and all combinations of parts, elements, steps, examples and / or features mentioned individually or collectively in the specification. In particular, one or more features in any embodiment described herein may be combined with one or more features in any other embodiment described herein.

[0103] Protection may be sought for any features disclosed in one or more of the published documents cited herein in combination with the present disclosure.

[0104] Although certain exemplary embodiments of the present invention have been described, the scope of the appended claims is not intended to be limited to only these embodiments. The claims should be interpreted literally, philologically, and / or by equivalence.

Claims

1. A rotary piston internal combustion engine, comprising: Engine housing; an output shaft configured to rotate about an axis relative to the engine housing to transmit power to a component to be operated; A rotating piston, eccentrically mounted on the output shaft; a first bearing configured to support and facilitate rotation of the output shaft, the first bearing being sandwiched between a first pair of seals; and A second bearing is configured to support and facilitate rotation of the rotary piston, the second bearing being sandwiched between a second pair of seals; wherein the output shaft defines an internal path including a first region for allowing lubricating material to flow between the first bearing and the second bearing in use.

2. A rotary piston internal combustion engine according to claim 1, wherein the internal path includes a second region for allowing lubricating substance to flow between the second bearing and the third bearing in use.

3. A rotary piston internal combustion engine according to claim 2, wherein the output shaft defines a hole extending at least partially along the axis, and the rotary piston internal combustion engine further includes a first barrier member, the first barrier member is located between the first area and the second area in the hole, wherein the first barrier member is configured to guide the lubricating substance from the first area to flow into the second bearing.

4. A rotary piston internal combustion engine according to claim 3, wherein the first blocking member is configured to prevent the lubricating substance from flowing along the hole and passing through the first blocking member.

5. The rotary piston internal combustion engine according to any one of claims 3 to 4, further comprising a second barrier member, wherein the second barrier member is located in the hole and is configured to guide the lubricating substance to flow from the second region into the third bearing.

6. A rotary piston internal combustion engine according to claim 5, wherein the second blocking member is configured to prevent lubricating material from flowing along the aperture and past the second blocking member.

7. A rotary piston internal combustion engine according to any one of claims 3 to 6, further comprising a rod located within the bore.

8. A rotary piston internal combustion engine according to claim 7, wherein the rod comprises one or both of the first blocking member and the second blocking member.

9. A rotary piston internal combustion engine according to claim 7 or 8, wherein the rod is biased towards the first bearing.

10. A rotary piston internal combustion engine according to any one of claims 2 to 9, wherein the third bearing is configured to support and facilitate rotation of the output shaft.

11. A rotary piston internal combustion engine according to any one of claims 2 to 9, wherein the third bearing is in fluid communication with the thrust bearing.

12. A rotary piston internal combustion engine according to claim 11, wherein the second bearing and the thrust bearing are arranged such that, in use, lubricating material is received by the thrust bearing from the second bearing in a direction parallel to the axis.

13. A rotary piston internal combustion engine according to claim 11 or 12, the thrust bearing comprising a first side and a second side, the second side being spaced apart from the first side along the axis, wherein the first side comprises an inlet for receiving lubricating substance from the third bearing and the second side comprises an outlet for lubricating substance to leave the thrust bearing.

14. A rotary piston internal combustion engine according to any one of claims 11 to 13, wherein the third bearing is sandwiched between the thrust bearing and the third seal.

15. A rotary piston internal combustion engine according to any preceding claim, wherein the first bearing and / or the third bearing (if present) comprises: ring; a cage located within the ring and mounted coaxially therewith; and Rolling elements, wherein the rolling elements are supported relative to the rings by a cage.

16. A rotary piston internal combustion engine according to claim 15, wherein the retainer defines an aperture extending from an outer surface to an inner surface thereof, and the aperture receives at least a portion of the rolling element.

17. A rotary piston internal combustion engine according to claim 15 or 16, wherein the ring includes an inlet arranged to receive a lubricating substance.

18. A rotary piston internal combustion engine according to claim 17, wherein the ring includes a channel extending around its outer surface, the channel being in fluid communication with the inlet.

19. A rotary piston internal combustion engine according to claim 18, wherein the inlet is formed in the passage.

20. A rotary piston internal combustion engine according to any preceding claim, wherein the first and / or second pair of seals comprises one or more seals configured to withstand hydraulic pressures of 300 kPa and above.

21. A rotary piston internal combustion engine according to claim 20, wherein the first pair of seals comprises a first seal configured to withstand a hydraulic pressure of 300 kPa and above and a second seal configured to withstand a hydraulic pressure of up to 299 kPa.

22. A rotary piston internal combustion engine according to any preceding claim, wherein the second bearing comprises a ring fixed relative to the inner periphery of the rotary piston.

23. A rotary piston internal combustion engine according to any preceding claim, further comprising a lubricating substance reservoir and a pump, wherein the pump is configured to pump lubricating substance from the lubricating substance reservoir to the first bearing.

24. A rotary piston internal combustion engine according to any one of claims 1 to 22, further comprising a rotor cooling system cavity and a lubricant reservoir, wherein in use the lubricant reservoir is pressurised by exhaust gas in the rotor cooling system cavity so that lubricant flows from the lubricant reservoir to the first bearing.

25. A vehicle or apparatus comprising a rotary piston internal combustion engine according to any preceding claim.

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