Turbomachine waste heat recovery expander using passive method of system flow control

Abstract

A waste heat recovery system for recovering rejected heat of an internal combustion engine is provided, the waste heat recovery system including a turboexpander. The turboexpander outputs power based on a working fluid and includes turbine blades rotatable by the working fluid, a shaft coupled to and rotatable by the turbine blades and extending along a longitudinal axis, and a nozzle assembly for directing the working fluid to the turbine blades for rotation of the turbine blades. The nozzle assembly includes a nozzle housing disposed about the shaft and adjacent the turbine blades, and a nozzle for accelerating the working fluid. The nozzle member defines a nozzle throat having a geometry. The waste heat recovery system further includes a passive control coupled to the nozzle member for directing the working fluid.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Patent Application No. 16 / 825,765, filed on March 30, 2020, which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure generally relates to a waste heat recovery system for recovering waste heat from internal combustion engines. Background Technology

[0004] Internal combustion engines (ICEs) convert chemical energy into shaft work during operation, discarding heat as a byproduct. Waste heat recovery systems convert this waste heat into useful work that can be used to reduce fuel consumption in motor vehicles.

[0005] Organic Rankine Cycle (ORC) waste heat recovery systems may include pumps, evaporators, expanders, and condensers. The expander extracts power output from a pressurized working fluid. Common types of expanders include: turbine blades that can be rotated by the working fluid, a shaft coupled to the turbine blades and capable of being rotated by the turbine blades and extending along a longitudinal axis, and a passageway that guides the working fluid to the turbine blades for rotating the turbine blades.

[0006] The ORC waste heat recovery system employs the Rankine process, which uses an organic fluid as the working fluid in a closed-loop thermodynamic cycle. In the ORC, the liquid working fluid is pumped to a higher pressure, evaporates into a vapor phase, and expands under high pressure to extract mechanical or electrical work. The working fluid is then condensed back into liquid and returned to the pump. Automotive ORC cycles utilize heat from the ICE (Industrial Equipment) that is typically discarded from the engine into the environment.

[0007] U.S. Patent Publication No. 2019 / 0264606, entitled "Waste Heat Recovery System and Turbine Expander Therefor," assigned to BorgWarner Inc., discloses an ORC waste heat recovery system in which turbine nozzles are actively actuated by a controller based on sensor feedback. While this type of solution offers performance advantages, the increased number of components with moving parts increases system cost, and the increased complexity may introduce reliability issues.

[0008] Therefore, an improved waste heat recovery system is still needed. Summary of the Invention

[0009] In one embodiment described in this disclosure, a turbine expander for output power based on a working fluid is described. The turbine may include turbine blades rotatable by the working fluid, and a shaft coupled to and rotatable by the turbine blades, the shaft extending along a longitudinal axis. It further includes a nozzle assembly for directing the working fluid to the turbine blades and for rotating the turbine blades. The nozzle assembly includes a nozzle housing disposed about the shaft and adjacent to the turbine blades, and a nozzle component for accelerating the working fluid. The nozzle component defines a nozzle throat having a specific geometry. A passive control element is coupled to the nozzle component and directs the working fluid. The passive control element may have a channel in fluid communication with the nozzle, and the channel includes a seal juxtaposed across the internal width of the channel. The seal is configured to move from a closed position to an open position.

[0010] In another embodiment described in this disclosure, an organic Rankine cycle waste heat recovery system for recovering waste heat from an internal combustion engine is provided. The waste heat recovery system includes an evaporator for transferring waste heat from the internal combustion engine to a working fluid, and a turboexpander for outputting power based on the working fluid. The turbine may include turbine blades rotatable by the working fluid, and a shaft coupled to and rotatable by the turbine blades, the shaft extending along a longitudinal axis. It further includes a nozzle assembly for directing the working fluid to the turbine blades and for rotating the turbine blades. The nozzle assembly includes a nozzle housing arranged about the shaft and adjacent to the turbine blades, and a nozzle component for accelerating the working fluid. The nozzle component defines a nozzle throat having a geometric configuration. A passive control is coupled to the nozzle component and directs the working fluid. The passive control may have a channel in fluid communication with the nozzle, and the channel includes a seal juxtaposed across the internal width of the channel. The seal is configured to move from a closed position to an open position. The system may further include: a condenser in fluid communication with the turboexpander for condensing the working fluid from a vapor state to a liquid state, and a pump for circulating the working fluid from the condenser to the evaporator.

[0011] In yet another embodiment described in this disclosure, a method for recovering waste heat from an internal combustion engine is provided. The method includes providing a turboexpander for output power based on a working fluid. The turboexpander may include: turbine blades rotatable by the working fluid, and a shaft coupled to and rotatable by the turbine blades, the shaft extending along a longitudinal axis. It further includes a nozzle assembly for directing the working fluid to the turbine blades and for rotating the turbine blades. The nozzle assembly includes a nozzle housing disposed about the shaft and adjacent to the turbine blades, and a nozzle component for accelerating the working fluid. The nozzle component defines a nozzle throat having a geometric configuration. A passive control element coupled to the nozzle component and directing the working fluid may have a channel in fluid communication with the nozzle, and the channel includes a seal juxtaposed across the internal width of the channel. The seal is configured to move from a closed position to an open position. The method further includes: guiding a first portion of the working fluid to a first passive control component of the one or more passive control components, and receiving the working fluid at a first nozzle component of the one or more nozzle components. Attached Figure Description

[0012] One or more embodiments of this disclosure will be described below in conjunction with the accompanying drawings, wherein like reference numerals denote like elements, and in the drawings:

[0013] Figure 1 It is a schematic diagram of a waste heat recovery system that includes a turboexpander and passive control components;

[0014] Figure 2 This is a perspective view of a turbine expander according to an exemplary embodiment of this disclosure;

[0015] Figure 3 yes Figure 1 A cross-sectional view of an exemplary nozzle assembly;

[0016] Figure 4 yes Figure 1 A perspective view of an exemplary turboexpander, the exemplary turboexpander including the bottom of the nozzle housing of the turboexpander;

[0017] Figure 5 yes Figure 1 A top view of an exemplary turboexpander, wherein the turboexpander includes a top of a nozzle housing, a first passive control connected to a first nozzle component shown in dashed lines, a second passive control connected to a second nozzle component shown in dashed lines, a third passive control connected to a third nozzle component shown in dashed lines, and a fourth passive control connected to a fourth nozzle component shown in dashed lines.

[0018] Figure 6 It is along Figure 5 A cross-sectional view of the first nozzle component and the fourth nozzle component taken by line AA;

[0019] Figure 7 This is a perspective view of a turbine expander according to an exemplary embodiment of this disclosure;

[0020] Figure 8 This is a perspective view of a turbine expander according to an exemplary embodiment of this disclosure;

[0021] Figure 9 It is a diagram depicting the variable inflow characteristics of the working fluid inside a turboexpander, including passive control components, as the pressure of the working fluid increases; and

[0022] Figure 10 It is a diagram depicting the variable inflow characteristics of the working fluid inside a turboexpander, including passive control components, when the pressure of the working fluid decreases. Detailed Implementation

[0023] See the accompanying drawings, in which the same reference numerals indicate the same parts in all of the views. Figure 1 The diagram schematically illustrates an Organic Rankine Cycle (ORC) waste heat recovery system 1 for recovering waste heat from an internal combustion engine (ICE). The waste heat recovery system 1 includes: a turboexpander 2 for output power based on a working fluid (not shown); a condenser 4 for condensing the working fluid from a vapor state (not shown) to a liquid state (not shown) after it passes through the turboexpander 2; a pump 6 for regulating the flow rate of the working fluid through the waste heat recovery system 1; an evaporator 8 for transferring heat discarded by the ICE to the working fluid; and a passive control unit 38 for guiding the working fluid to the turboexpander 2.

[0024] See Figures 2 to 6 And continue to see Figure 1 The turbine expander 2 includes turbine blades 16 that can be rotated by the working fluid. (As in...) Figure 2 As best shown, the turbine expander 2 also includes a shaft 17 coupled to and rotatable by the turbine blade 16. The shaft 17 extends along a longitudinal axis A. The working fluid causes the turbine blade 16 to rotate about the longitudinal axis A of the shaft 17.

[0025] See also Figure 2The turbine expander 2 further includes a nozzle assembly 20 for directing working fluid to the turbine blades 16. The nozzle assembly 20 includes a top nozzle housing 21 arranged about a shaft 17 and adjacent to the turbine blades 16. Typically, the nozzle housing 21 has an annular configuration. However, the nozzle housing 21 can have any configuration suitable for directing working fluid to the turbine blades 16. The nozzle housing 21 can have a top 22 facing the shaft 17 (as in...). Figure 2 (best shown in the middle), and the bottom 23 facing opposite to the top 22 (as shown in the middle). Figure 4 (best shown in the middle).

[0026] See Figure 3 and Figure 5 The nozzle assembly 20 also includes a nozzle component 26 coupled to the nozzle housing 21 for accelerating the working fluid. The nozzle component 26 defines a nozzle 28. In one embodiment, as... Figure 3 As shown, the nozzle component 26 is integral with the nozzle housing 21 (i.e., one-piece). In another embodiment, as described in further detail below, the nozzle component 26 may be separate from the nozzle housing 21 (i.e., not integral with the nozzle housing).

[0027] Nozzle 28 has a geometric configuration. This geometric configuration can be a converging configuration, a diverging configuration, or a de Laval (converging-diverging) configuration. Typically, the geometric configuration is as follows: Figure 3 and Figure 5 The de Laval configuration shown.

[0028] As in Figure 6 As best illustrated, when the geometry of nozzle 28 is a de Laval configuration, nozzle 28 may have a working fluid inlet 29, a converging section 31, a diverging section 32, a throat section 33 separating the converging section 31 and the diverging section 32, and a working fluid outlet 35. When present, the converging section 31 extends from the working fluid inlet 29 to the throat section 33. When the converging section 31 is present, the cross-sectional area of ​​nozzle 28 gradually decreases from the working fluid inlet 29 to the throat section 33. When the diverging section 32 is present, the cross-sectional area of ​​nozzle 28 gradually increases from the throat section 33 to the working fluid outlet 35. When present, the throat section 33 is the point where the cross-sectional area of ​​nozzle 28 is minimum. In the context of this disclosure, the minimum cross-sectional area of ​​nozzle 28 is referred to as the throat cross-sectional area 36.

[0029] The working fluid passes through the converging section 31 of the nozzle 28 to the throat section 33. If the working fluid has appropriate pressure, its velocity is choked at the throat section 33. Whether the working fluid has appropriate pressure to choke its velocity at the throat section 33 is based on the throat cross-sectional area 36. The working fluid expands in the diverging section 32, increasing its velocity. In this way, the nozzle 28 accelerates the working fluid.

[0030] As in Figure 3 As best illustrated, the working fluid is guided to the working fluid inlet 29 of the nozzle 28 after first passing through the passive control element 38. The passive control element 38 is coupled to the nozzle component 26 and includes a channel 39 in fluid communication with the nozzle 28. In one embodiment, as... Figure 3 As shown, the passive control element 38 is integral (i.e., one-piece) and defined by the nozzle component 26. In another embodiment, as described in further detail below, the passive control element 38 may be separate from the nozzle component 26 (i.e., not integral with the nozzle component).

[0031] In one exemplary embodiment, the passive control element 38 may further include a passive control element inlet 40, a seal 41 juxtaposed across the internal width of the channel 39, a biasing member 42, and a passive control element outlet 43. In an exemplary embodiment, the seal 41 prevents working fluid from entering the channel 39 until the pressure of the working fluid reaches a sufficiently large force to contact the seal 41 and move the seal from a closed position to an open position. The closed position is the position where the seal 41 is juxtaposed across the internal width of the channel 39, thus preventing working fluid from entering the channel 39 through the passive control element inlet 40, and the open position is the position where the seal 41 is removed from the juxtaposed position. In another exemplary embodiment, the biasing member 42 applies a force to the bottom 44 of the seal 41 to hold the seal 41 in the closed position, and the seal 41 moves to the open position when a force from the working fluid is applied to the top 45 of the seal 41 and the force is large enough to overcome the force applied by the biasing member 42. In another exemplary embodiment, the biasing member 42 is a spring, but in other embodiments, the seal 41 may include a component found in a valve that passively responds as a biasing member to changes in the working fluid temperature, working fluid pressure, or other inputs.

[0032] As described above, the passive control element 38 can be integral and defined by the nozzle component 26. In other embodiments, the passive control element 38 can be fixed to the nozzle component 26, for example, by welding, screwing, friction, etc. Figure 7As shown, the removable passive control element 47 can be removably coupled to the independent nozzle housing 50. When the removable nozzle component 52 is removably coupled to the independent nozzle housing 50, the independent nozzle housing 50 can define an aperture 53 for selectively receiving the removable nozzle component 52 coupled to the removable passive control element 47. In this way, the removable nozzle component 52 can be selectively arranged in the aperture 53. Advantageously, when the removable nozzle component 52 is removably coupled to the independent nozzle housing 50, the manufacturing complexity of the turboexpander 60 can be reduced. Specifically, the removable nozzle component 52 and the independent nozzle housing 50 can be independently machined and / or cast, thereby reducing manufacturing time and manufacturing costs.

[0033] When the threaded passive control element 48 is removably coupled to the threaded nozzle housing 51, the threaded nozzle component 54 of the threaded nozzle housing 51 may also include threads (not shown). The threaded passive control element 48 may also include threads (not shown), thereby allowing the threaded passive control element 48 to be removably coupled to the threaded nozzle component 54 of the turboexpander 56. In other embodiments, the threaded passive control element 48 may be removably coupled to the separate nozzle housing 51 via an interference fit or a transition fit.

[0034] The passive control element 38 may be further defined as a first passive control element 62, and the nozzle component 26 may be further defined as a first nozzle component 64. In addition, each segment of the nozzle component 26 may be further defined as a first segment (e.g., a first nozzle, a first throat segment, etc.).

[0035] See Figure 5 The nozzle assembly 20 may also include a second passive control element 68 coupled to a second nozzle component 70 for guiding working fluid. As shown, when present, the second nozzle component 70 defines a second nozzle 72. The second passive control element 68 may have a second channel 74, a second seal 75, a second biasing member 76, and a second passive control element inlet 77.

[0036] The second nozzle 72 has a second geometric configuration. The second geometric configuration can be a converging configuration, a diverging configuration, or a de Laval configuration. Typically, the second geometric configuration is as follows: Figure 5 The de Laval configuration is shown. When the second geometry is the de Laval configuration, the second nozzle 72 may have a second working fluid inlet 78, a second converging section 79, a second diverging section 80, a second throat section 82 separating the second converging section 79 and the second diverging section 80, and a second working fluid outlet 83.

[0037] In one embodiment, when present, the second geometry of the second nozzle 72 differs from the first geometry of the first nozzle 65. In some embodiments, the first and second geometries can be different types of configurations. For example, the first geometry can be a converging configuration, while the second geometry can be a de Laval configuration. In other embodiments, such as Figure 5 As shown, the first and second geometric configurations can be of the same type but have different corresponding sections. For example, when the first and second geometric configurations are de Laval configurations, at least one of the first working fluid inlet 84, the first converging section 85, the first throat section 66, the first diverging section 86, and the first working fluid outlet 87 is different from the corresponding second working fluid inlet 78, the second converging section 79, the second throat section 66, the second diverging section 80, and the second working fluid outlet 83 of the second nozzle 72.

[0038] In some embodiments, such as Figure 6 As shown, when the first and second geometries are de Laval configurations, the second throat cross-sectional area 88 differs from the first throat cross-sectional area 89. As described above, whether the velocity of the working fluid is choked at the first throat section 66 and the second throat section 82 is determined by the first throat cross-sectional area 89, the second throat cross-sectional area 88, and the working fluid pressure and mass flow rate. In one embodiment, the nozzles are designed to be optimal for different flow rates, and the first throat cross-sectional area 89 and the second throat cross-sectional area 88 are different. In this embodiment, the working fluid pressure and mass flow rate may be suitable for one of the first nozzles 65 and the second nozzle 72 to accelerate the working fluid, but not for the other nozzle. In another embodiment, the nozzles do not necessarily have to be different, as the working fluid flow rates will be cumulative. In this exemplary embodiment, when the second nozzle 72 is open, the first nozzle 65 will always be open.

[0039] Furthermore, in some embodiments, when both the first passive control element 62 and the second passive control element 68 are present, as described above, the magnitude of the force required to move the first seal 90 of the first passive control element 62 from the closed position to the open position can be different from the force required to move the second seal 75 of the second passive control element 68 from the closed position to the open position. Because these forces are different, the working fluid pressure and mass flow rate can be adapted to move either the first seal 90 or the second seal 75 (rather than the other of the first seal 90 and the second seal 75) from the closed position to the open position. During operation of the ICE, the heat recovered by the waste heat recovery system 1 can change the required working fluid pressure and mass flow rate, such that either or both (or neither) of the first seal 90 and the second seal 75 moves from the closed position to the open position. When the first seal 90 and the second seal 75 move to the open position, they accordingly direct the working fluid flow to the first nozzle 65 and the second nozzle 72, and expand the range of working fluid mass flow rates that the waste heat recovery system 1 can operate at a specific working fluid pressure. As described in further detail below, this advantageously allows the waste heat recovery system 1 to maintain maximum cycle efficiency and power output over a wider range of ICE operating conditions.

[0040] like Figure 2 As shown and described above, the second passive control element 68 can be integrally integrated with the nozzle housing 21. In other embodiments, the second passive control element 68 can be fixed to the nozzle housing 21, for example, by welding, screwing, friction, etc. Figure 7 and Figure 8 As shown, in another embodiment, the second removable passive control element 92 can be removably coupled to the independent nozzle housing 50. When the second removable passive control element 92 is removably coupled to the independent nozzle housing 50, the independent nozzle housing 50 can define a second orifice 93 for selectively receiving the second removable nozzle component 92. In this way, the second removable passive control element 92 can be selectively arranged in the second orifice 93.

[0041] When the second threaded passive control element 94 is removably connected to the threaded nozzle housing 51, the second threaded passive control element 94 may also include threads, thereby allowing the second threaded passive control element 94 to be removably connected to the threaded nozzle housing 51. In other embodiments, the second threaded passive control element 94 may be removably connected to the threaded nozzle housing 51 via an interference fit or a transition fit.

[0042] See you again Figure 5The nozzle assembly 20 may also include a third passive control element 95, which is coupled to a third nozzle component 97 for guiding the working fluid. As shown, when present, the third nozzle component 97 defines a third nozzle 98. The third passive control element 95 may have a third channel 99, a third seal 100, a third biasing member 101, and a third passive control element inlet 102.

[0043] The third nozzle 98 has a third geometric configuration. This third geometric configuration can be a converging configuration, a diverging configuration, or a de Laval configuration. Typically, the third geometric configuration is as follows: Figure 5 The de Laval configuration is shown. When the third geometry is the de Laval configuration, the third nozzle 98 may have a third working fluid inlet 104, a third converging section 106, a third diverging section 107, a throat section 108 separating the third converging section 106 and the third diverging section 107, and a third working fluid outlet 110.

[0044] In one embodiment, when present, the third geometry of the third nozzle 98 differs from the first geometry of the first nozzle 65 and the second geometry of the second nozzle 72. In some embodiments, the first, second, and third geometries can be different types of configurations. For example, the first or second geometry can be a converging configuration, while the third geometry can be a de Laval configuration. In other embodiments, such as Figure 5 As shown, the first, second, and third geometric configurations can be of the same type but have different corresponding sections. For example, when the first, second, and third geometric configurations are de Laval configurations, at least one of the following—the first working fluid inlet 84 and the second working fluid inlet 78, the first converging section 85 and the second converging section 79, the first throat section 66 and the second throat section 82, the first diverging section 86 and the second diverging section 80, and the first working fluid outlet 87 and the second working fluid outlet 83—is different from the corresponding third working fluid inlet 104, the third converging section 106, the third throat section 108, the third diverging section 107, and the third working fluid outlet 110 of the third nozzle 98.

[0045] In some embodiments, when the first, second, and third geometries are de Laval configurations, the third throat cross-sectional area 111 differs from the first throat cross-sectional area 89 and the second throat cross-sectional area 88. As described above, whether the velocity of the working fluid is choked at the first throat section 66, the second throat section 82, or the third throat section 108 is determined by the first throat cross-sectional area 89, the second throat cross-sectional area 88, and the third throat cross-sectional area 111, as well as the working fluid pressure and mass flow rate. Because the first throat cross-sectional area 89, the second throat cross-sectional area 88, and the third throat cross-sectional area 111 are different, the working fluid pressure and mass flow rate can be adapted to one of the first nozzle 65, the second nozzle 72, or the third nozzle 98 to accelerate the working fluid, rather than the other nozzle among the first nozzle 65, the second nozzle 72, and the third nozzle 98.

[0046] Furthermore, in some embodiments, when the first passive control element 62, the second passive control element 68, and the third passive control element 98 are present, as described above, the magnitude of the force required to move the first seal 90 of the first passive control element 62 from the closed position to the open position may be different from the force required to move the second seal 75 of the second passive control element 68 from the closed position to the open position or to move the third seal 100 from the closed position to the open position. Because these forces are different, the working fluid pressure may be adapted to move the first seal 90, the second seal 75, or the third seal 95 (rather than another seal among the first seal 90, the second seal 75, and the third seal 95) from the closed position to the open position. During ICE operation, the heat recovered by the waste heat recovery system 1 may change the working fluid pressure, causing any one, two, three, or none of the first seal 90, the second seal 75, and the third seal 95 to move from the closed position to the open position. When the first seal 90, the second seal 75, and the third seal 95 move to the open position, they correspondingly guide the working fluid to the first nozzle 65, the second nozzle 72, and the third nozzle 98, and expand the range of mass flow rates of the working fluid that the waste heat recovery system 1 can operate at a specific working fluid pressure. As described in further detail below, this advantageously allows the waste heat recovery system 1 to maintain maximum cycle efficiency and power output over a wider range of ICE operating conditions.

[0047] like Figure 2 As shown and described above, the third passive control component 95 can be integrally formed with the nozzle housing 21. In other embodiments, the third passive control component 95 can be fixed to the nozzle housing 21, for example, by welding, screwing, friction, etc. Figure 7 and Figure 8As shown, in other embodiments, the third removable passive control element 112 can be removably coupled to the independent nozzle housing 50. When the third removable passive control element 112 is removably coupled to the independent nozzle housing 50, the independent nozzle housing 50 can define a third aperture 113 for selectively receiving the third removable passive control element 112. In this way, the third removable passive control element 112 can be selectively arranged in the third aperture 113.

[0048] When the third threaded passive control element 114 is removably connected to the threaded nozzle housing 51, the third threaded passive control element 114 may also include threads, thereby allowing the third threaded passive control element 114 to be removably connected to the threaded nozzle housing 51. In other embodiments, the third threaded passive control element 114 may be removably connected to the threaded nozzle housing 51 via an interference fit or a transition fit.

[0049] See you again Figure 5 The nozzle assembly 20 may also include a fourth passive control element 95, which is coupled to a fourth nozzle component 116 for guiding the working fluid. As shown, when present, the fourth nozzle component 116 defines a fourth nozzle 118. The fourth passive control element 115 may have a fourth channel 119, a fourth seal 120, a fourth biasing member 121, and a fourth passive control element inlet 122.

[0050] The fourth nozzle 118 has a fourth geometric configuration. This fourth geometric configuration can be a converging configuration, a diverging configuration, or a de Laval configuration. Typically, the fourth geometric configuration is as follows: Figure 5 The de Laval configuration is shown. When the fourth geometry is the de Laval configuration, the fourth nozzle 118 may have a fourth working fluid inlet 124, a fourth converging section 126, a fourth diverging section 127, a fourth throat section 128 that separates the third converging section 126 from the third diverging section 127, and a fourth working fluid outlet 130.

[0051] In one embodiment, when present, the fourth geometry of the fourth nozzle 118 differs from the first geometry of the first nozzle 65, the second geometry of the second nozzle 72, and the third geometry of the third nozzle 98. In some embodiments, the first, second, third, and fourth geometries can be different types of configurations. For example, the first, second, or third geometry can be a converging configuration, while the fourth geometry can be a de Laval configuration. In other embodiments, such as... Figure 5As shown, the first, second, third, and fourth geometric configurations can be of the same type but have different corresponding sections. For example, when the first, second, third, and fourth geometric configurations are de Laval configurations, at least one of the following—first working fluid inlet 84, second working fluid inlet 78, and third working fluid inlet 104; first converging section 85, second converging section 79, and third converging section 106; first throat section 66, second throat section 82, and third throat section 108; first diverging section 86, second diverging section 80, and third diverging section 107; and first working fluid outlet 87, second working fluid outlet 83, and third working fluid outlet 110—is different from the corresponding fourth working fluid inlet 124, fourth converging section 126, fourth throat section 128, fourth diverging section 127, and fourth working fluid outlet 130 of the third nozzle 118.

[0052] In some embodiments, when the first, second, third, and fourth geometries are de Laval configurations, the fourth throat cross-sectional area 131 differs from the first throat cross-sectional area 89, the second throat cross-sectional area 88, and the third throat cross-sectional area 111. As described above, whether the velocity of the working fluid is choked at the first throat section 66, the second throat section 82, the third throat section 108, or the fourth throat section 128 is determined by the first throat cross-sectional area 89, the second throat cross-sectional area 88, the third throat cross-sectional area 111, and the fourth throat cross-sectional area 131, as well as the working fluid pressure. Because the cross-sectional areas of the first throat 89, the second throat 88, the third throat 111, and the fourth throat 131 are different, the working fluid pressure can be adapted to one of the first nozzle 65, the second nozzle 72, the third nozzle 98, or the fourth nozzle 118 for acceleration using the working fluid, rather than the other nozzle among the first nozzle 65, the second nozzle 72, the third nozzle 98, and the fourth nozzle 118.

[0053] Furthermore, in some embodiments, when a first passive control element 62, a second passive control element 68, a third passive control element 98, or a fourth passive control element 115 is present, as described above, the magnitude of the force required to move the first seal 90 of the first passive control element 62 from the closed position to the open position may be different from the force required to move the second seal 75 of the second passive control element 68 from the closed position to the open position, different from the force required to move the third seal 100 of the third passive control element 98 from the closed position to the open position, or different from the force required to move the fourth seal 120 of the fourth passive control element 115 from the closed position to the open position. Because these forces are different, the working fluid pressure may be adapted to move the first seal 90, the second seal 75, the third seal 95, or the fourth seal 120 (instead of another seal among the first seal 90, the second seal 75, the third seal 95, or the fourth seal 115) from the closed position to the open position. During ICE operation, the heat recovered by the waste heat recovery system 1 can alter the working fluid pressure and mass flow rate, causing any one, two, three, all four, or none of the first seal 90, second seal 75, third seal 95, or fourth seal 120 to move from the closed position to the open position. When the first seal 90, second seal 75, third seal 95, or fourth seal 120 moves to the open position, they correspondingly direct the working fluid flow to the first nozzle 65, second nozzle 72, third nozzle 98, or fourth nozzle 118, and expand the range of working fluid mass flow rates that the waste heat recovery system 1 can operate at specific working fluid pressures. As described further in detail below, this advantageously allows the waste heat recovery system 1 to maintain maximum cycle efficiency and power output over a wider range of ICE operating conditions.

[0054] like Figure 2 As shown and as described above, the fourth passive control element 115 can be integral with the nozzle housing 21. In other embodiments, the fourth passive control element 115 can be fixed to the nozzle housing 21. Figure 7 and Figure 8 As shown, in another embodiment, the fourth removable passive control 133 can be removably coupled to the independent nozzle housing 50. When the third removable passive control 133 is removably coupled to the independent nozzle housing 50, the independent nozzle housing 50 can define a fourth aperture 135 for selectively receiving the fourth removable passive control 133. In this way, the fourth removable passive control 133 can be selectively arranged in the fourth aperture 135.

[0055] When the fourth threaded passive control element 136 is removably connected to the threaded nozzle housing 51, the fourth threaded passive control element 136 may also include threads, thereby allowing the fourth threaded passive control element 136 to be removably connected to the threaded nozzle housing 51. In other embodiments, the fourth threaded passive control element 136 may be removably connected to the threaded nozzle housing 51 via an interference fit or a transition fit.

[0056] It should be understood that the nozzle assembly 20 may further include any number of additional nozzle components, and the description of nozzle component 26 or passive control element 38 is applicable to any additional nozzle component or passive control element. It should be further understood that any geometry of any nozzle defined by an additional nozzle component will differ from at least one of the nozzles included in the nozzle assembly. In this way, the operational range of the waste heat recovery system 1 can be further expanded by including additional nozzle components coupled to additional passive controls other than the first nozzle component 64, second nozzle component 70, third nozzle component 97, and fourth nozzle component 116 as described herein. For example, the nozzle assembly 20 may include five, six, seven, eight nozzle components or fewer than four nozzle components.

[0057] See you again Figure 1 The waste heat recovery system 1 includes a passive control 38 in fluid communication with the turboexpander 2 for directing working fluid to the turboexpander 2. In one embodiment, the passive control includes at least one of a first passive control 62, a second passive control 68, a third passive control 95, and / or a fourth passive control 115 contained in the turboexpander 2. In another embodiment, the first passive control 62, the second passive control 68, the third passive control 95, and / or the fourth passive control 115 are in fluid communication with the evaporator 8. In yet another embodiment, the pressure of the working fluid may not be high enough to force the first seal 90, the second seal 75, the third seal 95, or the fourth seal 115 from a closed position to an open position, in which case the working fluid is directed via a working fluid bypass 152 to bypass the turboexpander 2. Bypassing the turboexpander may be beneficial when the quality of the working fluid is at a low level that could damage the turboexpander, such as during vehicle startup.

[0058] like Figure 1 As shown, the waste heat recovery system 1 may also include an evaporator 8 in fluid communication with the flow control device 14 and the turboexpander 2. The evaporator 8 transfers the heat discarded by the ICE to the working fluid, thereby causing a phase change in the working fluid from a liquid state to a vapor state. When present, the evaporator 8 is arranged upstream of the passive control unit.

[0059] The waste heat recovery system 1 may also include a condenser 4 in fluid communication with the turbine expander 22 and passive controls. After the working fluid passes through the turbine expander 2, the condenser 4 condenses the working fluid from a vapor state to a liquid state. The condenser 4 is located downstream of the turbine expander 2. In some embodiments, when the waste heat recovery system 1 includes an evaporator 8, the condenser 4 is located downstream of the turbine expander 2 and upstream of the evaporator 8.

[0060] To ensure maximum cycle efficiency and power output of the waste heat recovery system 1, the combination of the working fluid passing through the first nozzle 65, second nozzle 72, third nozzle 98, and fourth nozzle 118 before rotating the turbine blades 16 is functionally based on the working fluid pressure. As described above, the heat discarded by the ICE is transferred to the working fluid by the waste heat recovery system 1, causing the working fluid to undergo a liquid-vapor phase change. The heat discarded by the ICE is based on changes in the ICE's speed and load (i.e., operating state). Thus, under certain operating states of the ICE (e.g., startup, acceleration, etc.), to maintain maximum cycle efficiency and power output of the waste heat recovery system 1, the heat discarded by the ICE and recovered by the waste heat recovery system 1 may cause the working fluid pressure to be unsuitable for one or more of the first nozzle 65, second nozzle 72, third nozzle 98, and fourth nozzle 118.

[0061] Based on the characteristics of the working fluid, the first passive control element 62, the second passive control element 68, the third passive control element 95, and / or the fourth passive control element 115, or control devices, are each adapted to control the flow rate of their corresponding first nozzle component 64, second nozzle component 70, third nozzle component 97, and / or fourth nozzle component 116 and to guide or regulate the working fluid, or are each adapted to bypass the turbine expander 2. Thus, each passive control element is configured to move from a closed position to an open position when the working fluid comes into contact with its corresponding seal and has a pressure sufficient to exceed a predetermined threshold. The threshold corresponds to the force required to overcome the bias member, and in one embodiment, the threshold further corresponds to a pressure or flow rate suitable for the corresponding connected nozzle to achieve maximum efficiency without damaging the turbine blades 16. In this way, the different geometries of the first nozzle 65, the second nozzle 72, the third nozzle 98, and / or the fourth nozzle 118 advantageously extend the operating range of the waste heat recovery system 1 by accelerating the working fluid over a wider range of working fluid pressures, mass flow rates, temperatures, etc. Furthermore, as the working fluid pressure and / or mass flow rate change during ICE operation, the waste heat recovery system 1 advantageously allows for a gradual increase in the working fluid flow to the turbine blades 16.

[0062] For example, during the transition from low to high heat availability of the ICE, the working fluid mass flow rate can initially be low to ensure maximum heat transfer to the working fluid for phase change, and then transition to a high flow rate to limit the evaporator outlet temperature. To maximize turbine performance, the working fluid pressure should be maintained within a narrow operating range determined by the turbine blade design. For turbines employing choke nozzles, the ideal nozzle cross-section is significantly smaller under initial lower availability conditions than under higher availability conditions, in order to maintain the pressure within a preferred narrow range. During this exemplary transition, the proposed passive control will initially direct the working fluid to at least one of the first nozzle 65, the second nozzle 72, the third nozzle 98, and / or the fourth nozzle 118, which has a smaller throat cross-sectional area. As the pressure increases during the transition, the passive control will allow flow to pass through at least one or more of the first nozzle 65, the second nozzle 72, the third nozzle 98, and / or the fourth nozzle 118. Despite the increase in system pressure, the pressure increment becomes significantly smaller due to the change in the relationship between flow rate and pressure as nozzle valves 65, 72, 98, and 118 gradually open due to the stepwise change in the total throat area.

[0063] In another example, during the transition from low to high thermal availability of the ICE, as described previously, the working fluid mass flow rate will initially be higher to regulate the working fluid temperature. As thermal availability decreases, the working fluid mass flow rate is reduced via the system controller to ensure the working fluid remains in a superheated vapor state during the transition. Again, the working fluid pressure should be maintained within the narrow operating range required to maximize turbine performance. As the working fluid mass flow rate and pressure decrease, the passive valves on the nozzle gradually close. Although the system pressure decreases throughout the transition, the pressure reduction is smaller due to the change in the flow-pressure relationship, and the stepwise change in the total throat area causes the nozzle valves 65, 72, 98, and 118 to gradually close.

[0064] See you again Figure 1 The waste heat recovery system 1 may also include a working fluid circuit 150 for circulating the working fluid. The working fluid circuit 150 fluidly connects the turboexpander 2, the passive control unit 38, the evaporator 8, and / or the condenser 116. The working fluid circuit 120 may further include a pump 6 for circulating the working fluid through the working fluid circuit 120.

[0065] Industrial applicability

[0066] The described embodiments of the exhaust gas recovery system 1 can be useful in a variety of applications where the present disclosure may benefit. The waste heat recovery system 1 employs an organic Rankine cycle (ORC) for recovering waste heat from an internal combustion engine (ICE). This energy capture efficiency, turboexpander reliability, and cost are improved by employing passive controls that independently guide the working fluid to nozzles with different sizes and throat area ratios.

[0067] See also Figures 1 to 8 , Figure 9 The first schematic diagram 200 depicts the variable inflow characteristics of the working fluid (specifically, ethanol at 220 degrees Celsius) in an exemplary pressurized exhaust gas recovery system 1. Figure 9 and Figure 10 In the example above, each listed passive control seal is held juxtaposed by a biasing member, and the seal moves from a closed position to an open position when the working fluid comes into contact with the seal and has sufficient pressure to force the seal out of juxtaposition. As shown above, in another example, each passive control may have a seal that can be included in a component found in a valve that passively responds to working fluid temperature, working fluid pressure, or other inputs as a biasing member, and the seal can move from a closed position to an open position due to characteristics of the working fluid, such as temperature, flow rate, or pressure.

[0068] In the first schematic diagram 200, a first portion of the working fluid (not shown) reaches the first seal 90 of the first passive control 62. When the pressure of the first portion 201 of the working fluid is sufficient to overcome the threshold pressure of the first seal 90, the first passive control 62 moves to the open position at the first point 202, allowing a second portion (not shown) of the working fluid to flow to the first nozzle 65 and be directed to the turbine blades. A third portion 205 of the working fluid continues to flow through the working fluid circuit 150. Once the pressure of the working fluid reaches the threshold pressure of the second seal 75, the second passive control 68 moves from the closed position to the open position, and a fourth portion (not shown) of the working fluid flows to the second nozzle 72 and is directed to the turbine blades 16. Furthermore, once the pressure in the fluid working circuit reaches the pressure thresholds of the third seal 100 and the fourth seal 120, the third passive control 95 and the fourth passive control 115 open accordingly, and a portion of the working fluid is directed through each passive control to the turbine blades.

[0069] Figure 10The second schematic diagram 212 depicts the variable inflow characteristics of the working fluid (specifically, ethanol at 220 degrees Celsius) in the exemplary reduced-pressure waste heat recovery system 1. In this diagram, as the pressure in the working loop 150 decreases, the fourth passive control 115 moves to the closed position at the fifth point 212, the third passive control 95 moves to the closed position at the sixth point 214, the second passive control 68 moves to the closed position at the seventh point 216, and the first passive control 62 moves to the closed position at the eighth point 218.

[0070] Furthermore, it should be understood that the above description may be of only one embodiment of this disclosure. However, this disclosure is not limited to the one or more specific embodiments disclosed. For example, different variations of the turbine may be designed as radial flow, Pelton, or reaction turbines. Moreover, except for terms or phrases that may be explicitly defined elsewhere, statements in the specification relating only to specific embodiments should not be construed as limiting the scope of this disclosure or the specific terminology used in the claims. Various other embodiments, changes and modifications to one or more of the disclosed embodiments will be apparent to those skilled in the art and are intended to fall within the spirit and scope of the appended claims.

[0071] As used in this disclosure, the various terms “for example,” “like,” “for instance,” “as,” and “like,” as well as the verbs “including,” “having,” “containing,” and other verb forms, when used in conjunction with a list of one or more components or other items, shall be interpreted as open-ended, meaning that the list shall not be considered to exclude other or additional components or items. Unless used in a context that explicitly requires a specific interpretation, all terms shall be given their broadest reasonable meaning.

Claims

1. A turbine expander for outputting power extracted from a working fluid, the turbine expander comprising: Turbine blades capable of being rotated by the working fluid; A shaft connected to and rotatable by the turbine blades, the shaft extending along a longitudinal axis; A nozzle assembly for directing the working fluid to the turbine blades for rotating the turbine blades, the nozzle assembly including a nozzle housing arranged about the axis and adjacent to the turbine blades, and a nozzle component for accelerating the working fluid, the nozzle component defining a nozzle throat having a geometric configuration. as well as A passive control element connected to the nozzle component for guiding the working fluid, the passive control element including a channel in fluid communication with the nozzle, the channel including a seal juxtaposed across the internal width of the channel, and the seal being configured to move from a closed position to an open position; The nozzle assembly has a first nozzle component connected to a first passive control and a second nozzle component connected to a second passive control; the first nozzle component receives a first portion of the working fluid at a first pressure, and the second passive control receives a second portion of the working fluid at a second pressure, the second pressure being sufficiently large to force the seal of the second passive control to disengage and be placed.

2. The turbine expander as described in claim 1, wherein, The geometry is a de Laval configuration, which has a throat cross-sectional area defined by a converging section that is in fluid connection with the diverging section.

3. The turbine expander as described in claim 1, wherein, The seal is held in juxtaposition by a biasing member, and when the working fluid comes into contact with the seal and has sufficient pressure to force the seal out of juxtaposition, the seal moves from the closed position to the open position.

4. The turbine expander as described in claim 3, wherein, The biasing component is a spring.

5. The turbine expander as described in claim 1, wherein, The second pressure is greater than the first pressure.

6. The turboexpander of claim 5, further comprising a third nozzle component coupled to a third passive control element configured to receive a third portion of the working fluid at a third pressure.

7. The turbine expander as claimed in claim 1, wherein, The nozzle component is integrated with the nozzle assembly.

8. An organic Rankine cycle waste heat recovery system for recovering waste heat from an internal combustion engine, the waste heat recovery system comprising: An evaporator for transferring waste heat from an internal combustion engine to a working fluid; A turbine expander for output power based on the working fluid, the turbine expander comprising: Turbine blades capable of being rotated by the working fluid. A shaft connected to and rotatable by the turbine blades, wherein the shaft extends along a longitudinal axis. A nozzle assembly for directing the working fluid to the turbine blades to rotate the turbine blades, the nozzle assembly including a nozzle housing arranged about the axis and adjacent to the turbine blades, and a nozzle component coupled to the nozzle housing for accelerating the working fluid, the nozzle component defining a nozzle throat having a geometric configuration, and A passive control element connected to the nozzle component for guiding the working fluid, the passive control element including a channel in fluid communication with the nozzle, a seal juxtaposed across the internal width of the channel, and the seal being configured to move from a closed position to an open position when the working fluid comes into contact with the seal; A condenser, in fluid communication with the turboexpander, is used to condense the working fluid from a vapor state to a liquid state; and A pump that circulates working fluid from the condenser to the evaporator; The nozzle assembly has a first nozzle component connected to a first passive control and a second nozzle component connected to a second passive control; the first nozzle component receives a first portion of the working fluid at a first pressure, and the second passive control receives a second portion of the working fluid at a second pressure, the second pressure being sufficiently large to force the seal of the second passive control to disengage and be placed.

9. The system of claim 8, wherein, The pump increases the pressure of the working fluid.

10. The system of claim 9, wherein, When the seal is in the closed position, the working fluid flows through the working fluid bypass, and when the seal is in the open position, the working fluid is directed to the turbine blades.

11. The system of claim 8, wherein, The passive control element can be removed from the nozzle component.

12. The system of claim 8, wherein, The second nozzle component is attached to the nozzle housing.

13. The system of claim 12, wherein, The first portion of the working fluid is guided to the turbine blade through the first nozzle component, and the second portion of the working fluid is guided to the turbine blade through the second nozzle component.

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