Patent Application
20250084783
The application relates generally to internal combustion engines and, more particularly, to rotary internal combustion engines and to cooling systems of such engines.
Combustion chambers of a rotary engine, such as a Wankel engine, are delimited radially by the rotor and rotor housing and axially by a side housing. The side housing faces the combustion chambers and is thus subjected to high pressure and thermal loads. On the other hand, the side housing provides the running surface for the rotor's side seals. During use, the rotor housing becomes hot and requires cooling. Existing cooling systems may require intricate sealing arrangements between adjacent rotor and side housings to prevent leakage. Continuous improvements are sought.
In one aspect, there is provided a rotary engine, comprising: housings secured to one another, the housings including a first side housing, a second side housing, and a rotor housing disposed between the first side housing and the second side housing; and a rotor rotationally received within a rotor cavity defined by the first side housing, the second side housing, and the rotor housing; wherein the first side housing, the rotor housing, and the second side housing are cooled in parallel via respective coolant passages including: a first side housing coolant passage extending through the first side housing; a second side housing coolant passage extending through the second side housing; and a rotor housing coolant passage extending through the rotor housing, and wherein the coolant passages are free of inter-passage connection between the housings.
The rotary engine described above may include any of the following features, in any combinations.
In some embodiments, flow paths extend through the housings, the flow paths including a first flow path extending within the first side housing coolant passage, a second flow path extending within the second side housing coolant passage, and a third flow path extending within the rotor housing coolant passage, the flow paths free from intersection with one another.
In some embodiments, the flow paths are free from intersection with mounting interfaces between the housings.
In some embodiments, the coolant passages are fluidly connected in parallel to a source of coolant via a valve, having a closed configuration and one or more open configurations each having a respective flow circulating area for varying a flow rate of a coolant through the coolant passages.
In some embodiments, the valve includes a first valve in fluid communication with the first and second side housing coolant passages and a second valve in fluid communication with the rotor housing coolant passage.
In some embodiments, the valve is located downstream of the housings, the valve being a thermostatic valve operable to move from the closed configuration to one of the one or more open configurations when a temperature of the coolant flowing through the housings exceeds a temperature threshold.
In some embodiments, a heat exchanger is fluidly connected to respective outlets of the coolant passages, the heat exchanger providing heat exchange relationship between a coolant and a heat-transfer medium.
In some embodiments, a bypass valve is between the housings and the heat exchanger, the bypass valve operable to selectively fluidly connect the coolant passages to the heat exchanger or to a bypass conduit bypassing the heat exchanger.
In some embodiments, the rotor housing coolant passage includes a first section and a second section spaced apart from the first section, the rotor housing including a coolant port, a coolant inlet, and a coolant outlet, the first section fluidly connecting the coolant inlet to the coolant port, the second section fluidly connecting the coolant outlet to the coolant port.
In some embodiments, the housings further include an intermediate housing disposed between the first side housing and the second side housing and wherein the rotor housing includes a first rotor housing and a second rotor housing, the first rotor housing disposed between the first side housing and the intermediate housing, the second rotor housing disposed between the second side housing and the intermediate housing, the intermediate housing including an intermediate housing coolant passage fluidly separated from the first side housing coolant passage, the second side housing coolant passage, and the rotor housing coolant passage, and wherein the intermediate housing coolant passage, the first side housing coolant passage, the second side housing coolant passage, and the rotor housing coolant passage being fluidly connected in parallel with no coolant flow connection across the housings.
In another aspect, there is provided a rotary engine, comprising: housings secured to one another, the housings including a first side housing, a second side housing, and a rotor housing clamped in sandwich between the first side housing and the second side housing; a rotor rotationally received within a rotor cavity defined by the housings; and a parallel flow coolant circuit operable to individually cool the first side housing, the second side housing, and the rotor housing, the parallel flow coolant circuit having first, second, and third coolant passages extending respectively through the first side housing, the second side housing, and the rotor housing, wherein the first, second, and third coolant passages are fluidly independent from one another.
The rotary engine described above may include any of the following features, in any combinations.
In some embodiments, flow paths extend through the housings, the flow paths including a first flow path extending within the first coolant passage, a second flow path extending within the coolant passage, and a third flow path extending within the third coolant passage, the flow paths free from intersection with one another.
In some embodiments, the flow paths are free from intersection with mounting interfaces between the housings.
In some embodiments, the first, second, and third coolant passages are fluidly connected in parallel to a source of coolant via a valve, having a closed configuration and one or more open configurations each having a respective flow circulating area for varying a flow rate of a coolant through the first, second, and third coolant passages.
In some embodiments, the valve includes a first valve in fluid communication with the first and second coolant passages and a second valve in fluid communication with the third coolant passage.
In some embodiments, the valve is located downstream of the housings, the valve being a thermostatic valve operable to move from the closed configuration to one of the one or more open configurations when a temperature of the coolant flowing through the housings exceeds a temperature threshold.
In some embodiments, a heat exchanger is fluidly connected to respective outlets of the first, second, and third coolant passages, the heat exchanger providing heat exchange relationship between a coolant and a heat-transfer medium.
In some embodiments, a bypass valve is between the housings and the heat exchanger, the bypass valve operable to selectively fluidly connect the first, second, and third coolant passages to the heat exchanger or to a bypass conduit bypassing the heat exchanger.
In some embodiments, the third coolant passage includes a first section and a second section spaced apart from the first section, the rotor housing including a coolant port, a coolant inlet, and a coolant outlet, the first section fluidly connecting the coolant inlet to the coolant port, the second section fluidly connecting the coolant outlet to the coolant port.
In yet another aspect, there is provided a rotary engine, comprising: a stack of housings secured to one another and abutting one another at mounting interfaces, the housings including: a first side housing, a second side housing, an intermediate housing, a first rotor housing disposed between the first side housing and the intermediate housing, and a second rotor housing disposed between the intermediate housing and the second side housing; and rotors rotationally received within rotor cavities defined by the housings, the housings being cooled in parallel via respective coolant passages extending from respective inlets to respective outlets, the respective coolant passages free from intersection with the mounting interfaces, the mounting interfaces being free of a coolant seal.
In still yet another aspect, there is provided a motor assembly, comprising: a plurality of power modules, each power module of the plurality of power modules being operable to generate a force; a fluid supply manifold; a fluid outlet manifold; and a plurality of fluid conduits that fluidly connect the fluid supply manifold to the fluid outlet manifold and that are free from fluid interconnections fluidly between the fluid supply manifold and the fluid outlet manifold; and wherein each fluid conduit of the plurality of fluid conduits is defined in part by a power module of the plurality of power modules.
The motor assembly described above may include any of the following features, in any combinations.
In some embodiments, the plurality of power modules include a power module that is a thermal engine module.
In some embodiments, flow paths extend through the housings, the flow paths including a first flow path extending within the first coolant passage, a second flow path extending within the second coolant passage, and a third flow path extending within the third coolant passage, the flow paths free from intersection with one another.
In some embodiments, the thermal engine module is a rotary engine module.
In some embodiments, the plurality of power modules includes a power module that is an electric power module.
In some embodiments, the first, second, and third coolant passages are fluidly connected in parallel to a source of coolant via a valve, having a closed configuration and one or more open configurations each having a respective flow circulating area for varying a flow rate of a coolant through the first, second, and third coolant passages.
Reference is now made to the accompanying figures in which:
Referring now to
In the depicted embodiment, the outer body 12 further includes an intermediate housing 19 and the rotor housing 18 includes two rotor housings. Each of the rotor housings 18 is disposed between a respective one of the side housings 11 and the intermediate housing 19. Put differently, the rotor housing 18 includes a first rotor housing and a second rotor housing. The first rotor housing is disposed between a first one of the side housings 11 and the intermediate housing 19. The second rotor housing disposed between a second one of the side housings 11 and the intermediate housing 19. Regardless of a number of rotors, the rotary engine includes only two side housings disposed at opposite ends of the engine. A number of the intermediate housing 19 equals a number of the rotor minus 1 (e.g., one intermediate housing for a two-rotor engine, two intermediate housings for a three-rotor engine, and so on). The different housings are clamped in sandwich.
The side housings 11, the intermediate housing 19, and the rotor housings 18 conjointly define rotor cavities 20 (
Still referring to
Referring now to
The combustion chambers 32 are sealed. In the embodiment shown, each rotor apex portion 28 has an apex seal 34 extending from one end face 24 to the other and biased radially outwardly against the rotor housing 18. An end seal 36 engages each end of each apex seal 34 and is biased against the respective side housing 11. Each end face 24 of the rotor 22 has at least one arc-shaped face seal 38 running from each apex portion 28 to each adjacent apex portion 28, adjacent to but inwardly of the rotor periphery throughout its length, in sealing engagement with the end seal 36 adjacent each end thereof and biased into sealing engagement with the adjacent side housings 11. Alternate sealing arrangements are also possible.
Although not shown in the Figures, the rotor 22 is journaled on an eccentric portion of a shaft such that the shaft rotates the rotor 22 to perform orbital revolutions within the rotor cavity 20. The shaft may rotate three times for each complete rotation of the rotor 22 as it moves around the rotor cavity 20. Oil seals are provided around the eccentric to impede leakage flow of lubricating oil radially outwardly thereof between the respective rotor end face 24 and side housings 11. During each rotation of the rotor 22, each chamber 32 varies in volumes and moves around the rotor cavity 20 to undergo the four phases of intake, compression, expansion and exhaust, these phases being similar to the strokes in a reciprocating-type internal combustion engine having a four-stroke cycle.
The engine includes a primary inlet port 40 in communication with a source of air and an exhaust port 42 In the embodiment shown, the ports 40, 42 are defined in the rotor housing 18. Alternate configurations are possible.
In a particular embodiment, fuel such as kerosene (jet fuel) or other suitable fuel is delivered into the chamber 32 through a fuel port (not shown) such that the chamber 32 is stratified with a rich fuel-air mixture near the ignition source and a leaner mixture elsewhere, and the fuel-air mixture may be ignited within the housing using any suitable ignition system known in the art (e.g. spark plug, glow plug). In a particular embodiment, the rotary unit 10 operates under the principle of the Miller or Atkinson cycle, with its compression ratio lower than its expansion ratio, through appropriate relative location of the primary inlet port 40 and exhaust port 42.
Referring to
Typically, rotary engines are cooled by coolant passages that extend from one housing to the next in an axial direction relative to an axis of rotation of a shaft driven by the rotors. This may require complex sealing arrangements between the different housings (e.g., side housings 11, rotor housings 18, intermediate housings 19). Moreover, the side housing 11 located at the end of the loop is less cooled since the coolant has already picked up heat from the upstream housings. Moreover, in some configurations, it may be desired to vary the quantity of coolant flown in the coolant passage to increase or decrease the cooling of the housing(s). The cooling systems disclosed below may at least partially alleviate these drawbacks.
Referring back to
Referring now to
Still referring to
Referring back to
It will be appreciated that, in some embodiments, the rotary engine 10 may not require three-piece housings. Hence, the rotary engine 10 includes at least one flow path per housing; the flow paths of different housing are free from interconnection from one another. In other words, the flow path(s) of each housing are fluidly independent from one another.
Consequently, there may be no sharing of coolant between the different housings. Each of the housings have dedicated inlets and outlets and the coolant passages of these housings are free of intersection with mounting interfaces defined between these housings. These mounting interfaces correspond to mating faces of the different housings. In other words, the side housing coolant passage 11C extends along a flow path that is free from intersection with an interface between the side housing 11 and the rotor housing 18. The rotor housing coolant passage 18C extends along a flow path that is free from intersection with an interface between the rotor housing 18 and the side housing 11 and free from intersection with an interface between the rotor housing 18 and the intermediate housing 19. The intermediate housing coolant passage 19B extends along a flow path that is free from intersection with interfaces between the intermediate housing 19 and both of the rotor housings 18 located on opposite sides thereof. The interfaces between the housings are free of coolant seal. A coolant seal is a seal (e.g., elastomeric member) used for preventing coolant leakage. A lubricant seal or a combustion gas seal may be disposed at interfaces between the housings to prevent leakage of lubricant or combustion gases, but there may be no seal used for preventing leakage of coolant at the interfaces between the housings. The configuration of the distinct fluidly independent coolant passages may render obsolete the use of coolant seal between the housings.
Still referring to
Referring now to
As illustrated in
A valve 62 may fluidly connect the source of coolant S to the coolant passages such that the coolant flows to the rotary engine 100 through the valve 62. The valve 62 has a closed configuration in which the valve 62 blocks fluid communication between the source of coolant S and the coolant passages, and one or more open configurations in which the valve 62 fluidly connects the source of coolant S to the coolant passages. The valve 62 thus has a plurality of positions each defining a respective flow circulating area to adjust a mass flow rate of the coolant that reaches the coolant passages. In some embodiments, the valve 62 may be omitted and the pump 61 may be used to adjust the mass flow rate of the coolant. The pump 61 may be driven at a plurality of speeds each associated with a respective coolant mass flow rate.
In the embodiment illustrated, the coolant is a dedicated coolant, such as water or any other suitable fluid (e.g., ethylene-glycol). That is the coolant is different than a lubricant used for lubricating the rotary engine 100. Put differently, a lubrication system and a coolant system of the rotary engine 100 are fluidly separated from one another. There may be no mixture between the coolant system and the lubrication system. They each flow via dedicated fluidly separated passages. The coolant is therefore a fluid different than a lubricant used for lubricating parts of the rotary engine 100. In some embodiments, the lubricating fluid and the cooling fluid may be the same fluid (e.g., oil), but each flows within its own dedicated and separated circuits.
The valve 62 flows the coolant to the different coolant passages. The coolant picks up heat from the housings 11, 18 and the heated coolant flows out of the housings 11, 18 to reach a heat exchanger 63 to be cooled. The heat exchanger 63 may be an air-cooled cooler (or any other suitable cooler) and has at least one first conduit in fluid flow communication with the different coolant passages of the housings 11, 18 and at least one second conduit in fluid communication with a source of a heat-transfer medium (e.g., air). The at least one first conduit is in heat exchange relationship with the at least one second conduit to transfer heat from the coolant to the heat-transfer medium via their respective passages in the heat exchanger 63. The heat-transfer medium may be, for instance, air of an environment outside an aircraft or another vehicle equipped with the rotary engine 100. The heat-transfer medium may be, alternatively, fuel flowing from a fuel tank to the rotary engine 100 since the fuel may be colder than the coolant. The heat exchanger 63 has an inlet receiving the coolant from the housings 11, 18 and an outlet fluidly connected to the source of coolant S via a return conduit 64. Although not illustrated, a coolant manifold may be used to divide an incoming flow of coolant from the pump 61 to divide the coolant between the different rotary units and another coolant manifold may be used to combine flows of coolant exiting the housings 11, 18 to converge them towards a single inlet of the heat exchanger 63.
The rotary engine 100 may include a bypass valve 65, which may be omitted in some embodiments, operable to selectively fluidly connect the housings 11, 18 to the heat exchanger 63 or to fluidly connect the housings 11, 18 to the source of coolant S independently of the heat exchanger 63. Put differently, the bypass valve 65 has a first configuration in which the housings 11, 18 are fluidly connected to the source of coolant S through the heat exchanger 63 and a second configuration in which the housings 11, 18 are fluidly connected to the source of coolant S via a bypass conduit 66 while bypassing the heat exchanger 63. The bypass conduit 66 extends from the bypass valve 65 to the return conduit 64 downstream of the outlet of the heat exchanger 63 such that a flow path through the bypass conduit 66 bypasses the heat exchanger 63. Therefore, in the second configuration of the bypass valve 65, the coolant flows directly out of the housings 11, 18 into the source of coolant S via the bypass conduit 66 and does not flow through the heat exchanger 63.
The valve 62 in this configuration is located upstream of the housings 11, 18 relative to a flow of coolant and may be controlled by a controller causing its closing or opening. Alternatively, the valve 62 may be located downstream of the housings 11, 18 and may be a thermostatic valve including a wax motor. This alternate position of the valve 62 is shown at 62′ in
Contrary to previous cooling systems, the coolant is not shared between the different housings. As aforementioned, each of the housings may be cooled via a dedicated flow of coolant that flows through only one of the housings at a time. This may allow the removal of any seal at interfaces between the different housings, such as between the rotor housing 18 and the side housings 11.
Referring now to
The cooling system 160 may allow to control a mass flow of coolant through the housings 11, 18 independently from one another. Therefore, the valve 62 may include a first valve 62A fluidly connecting the source of coolant S to the side housing coolant passage 11C one of the side housings 11, a second valve 62B fluidly connecting the source of coolant S to the side housing coolant passage 11C of the other of the side housings 11, and a third valve 62C fluidly connecting the source of coolant S to the rotor housing coolant passage 18C of the rotor housing 18. The first, second, and third valves 62A, 62B, 62C may be operatively controlled by a controller. Alternatively, they may be located downstream of the housings 11, 18 and be thermostatic valve as described herein above with reference to
In some configurations, heat to be extracted from one of the side housings 11 may be the same as the heat to be extracted from the other of the side housings 11 due to a symmetry of the rotary engine 100. In such a case, the first and second valves 62A, 62B may be replaced by a single valve that fluidly connects the source of coolant S to both of the side housings 11. Similarly, two of the bypass valves may be replaced by a single one to selectively flow the coolant exiting the two side housings 11 through the heat exchanger 63 or to bypass the heat exchanger 63 via the bypass conduits.
Referring to
In this embodiment, the pump 61 drives the flow of coolant from the source of coolant S to the different housings through the valve 62, which may be selectively closed or opened at a plurality of positions to control a flow rate of coolant through the housings 11, 18, 19. The valve 62 be a thermostatic valve located downstream of the housings as previously described. The valve 62 may be controlled by a controller.
The coolant may thus be divided between the side housing coolant passages 11C, the rotor housing coolant passage 18C, and the intermediate housing coolant passage 19B. Each of these coolant passages are fluidly separated and independent from one another as discussed above. Hence, the coolant entering one of these housings 11, 18, 19 exit the same one of these housings 11, 18, 19. The coolant passages 11C, 18C, 19B are free of a seal at mounting interfaces between the intermediate housing 19 and the rotor housings 18 and between the rotor housings 18 and the side housings 11. The coolant passages of the rotary engine are in parallel to one another.
Referring now to
In this configuration, the flow rate of coolant through each of the side housings 11, rotor housings 18, and intermediate housing 19 may be individually controlled independently from one another. First and second valves 62A, 62B fluidly connect the source of coolant S to the side housing coolant passages 11C of the side housings 11; third and fourth valves 62C, 62D fluidly connect the source of coolant S to the rotor housing coolant passages 18C of the rotor housings 18; and a fifth valve 62E fluidly connects the source of coolant S to the intermediate housing coolant passage 19B of the intermediate housing 19. In some configurations, the first and second valves 62A, 62B may be replaced by a single valve since a cooling requirement of these housings may be the same due to symmetry of the engine. Similarly, third and fourth valves 62C, 62D may be replaced by a single valve since cooling requirement of these housings may be the same due to symmetry of the engine. The valves 62A, 62B, 62C, 62D, 62E may be controlled by a controller or may be thermostatic valve located downstream of the housings 11, 18, 19 as previously discussed.
First, second, third, fourth, and fifth bypass valves 65A, 65B, 65C, 65D, and 65E are used to selectively flow the coolant exiting the housings 11, 18, 19 to the heat exchanger 63 or directly back to the source of coolant S while bypassing the heat exchanger 63 and via respective first, second, third, fourth, and fifth bypass conduits 66A, 66B, 66C, 66D 66E. It will be appreciated that, for symmetry reason, the first and second bypass valves 65A, 65B may be replaced by a single valve. For this reason also, the third and fourth bypass valves 65C, 65D may be replaced by a single valve.
The different rotary engines and coolant systems disclosed herein may simplify assembly of the rotary engines since it may no longer be required to use seals at the mounting interfaces between the different housings to prevent coolant leakage. Indeed, by each having their own and respective coolant passages, interfaces between these housings may be substantially coolant leak-proof. Wear and tear issues of those seals may, at the same time, be eliminated by the removal of the coolant seals.
The embodiments described in this document provide non-limiting examples of possible implementations of the present technology. Upon review of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made to the embodiments described herein without departing from the scope of the present technology. Yet further modifications could be implemented by a person of ordinary skill in the art in view of the present disclosure, which modifications would be within the scope of the present technology.
