WASTE HEAT RECOVERY SYSTEM AND TURBINE EXPANSOR THEREFOR

Abstract

To provide a turbine expander for a waste heat recovery system for recovering waste heat in an internal combustion engine.SOLUTION: A turbine expander 22 includes a turbine blade, a shaft coupled to and rotatable by the turbine blade, and a nozzle assembly. The nozzle assembly includes a nozzle block disposed about the shaft and adjacent to the turbine blade, a first nozzle component coupled to the nozzle block, and a second nozzle component coupled to the nozzle block. The first nozzle component defines a first nozzle having a first geometrical configuration. The second nozzle component defines a second nozzle having a second geometrical configuration that is different from the first geometrical configuration. A waste heat recovery system 20 also includes a flow control device 24 in fluid communication with the turbine expander 22. The waste heat recovery system 20 further includes a controller 26 in communication with the flow control device 24.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates generally to a waste heat recovery system for recovering waste heat from an internal combustion engine. [Background technology]

[0002] During operation, an internal combustion engine (ICE) generates thrust and / or power and releases heat as a by-product. In the automotive industry, waste heat recovery systems typically utilize such wasted heat to produce electricity that can also be used to power the electronic components of the vehicle.

[0003] A conventional waste heat recovery system includes a turbine expander, a flow control device, and a controller. The turbine expander outputs power based on a working fluid. Specifically, in the conventional waste heat recovery system, the turbine expander 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 to rotate the turbine blades.

[0004] A conventional nozzle assembly includes a nozzle block, a first nozzle component, and a second nozzle component. The nozzle block is disposed about a shaft and adjacent to a turbine expander. The first nozzle component is integral with the nozzle block to accelerate a working fluid and defines a first nozzle, and the second nozzle component is integral with the nozzle block to accelerate a working fluid and defines a second nozzle. In the conventional nozzle component, the first and second nozzles have the same geometric configuration.

[0005] Conventional waste heat recovery systems utilize the organic Rankine cycle (ORC). ORC is named for the use of an organic high molecular weight working fluid that has a liquid-vapor phase change that occurs at a lower temperature than the water-steam phase change. The working fluid may include at least one of ethanol, methanol, kerosene, gasoline, diesel, propanol, butanol, water, benzene, toluene, methane, ethane, propane, butane, acetone, or liquid hydrogen. Heat rejected by the ICE heats the working fluid such that it undergoes a liquid-vapor phase change from a liquid state to a vapor state. In the vapor state, the working fluid is better suited to rotate turbine blades.

[0006] In recent years, there has been a demand to improve the efficiency and overall performance of waste heat recovery systems. To help improve the efficiency and overall performance of waste heat recovery systems, there has been a demand to extend the operating range and improve controllability. In conventional waste heat recovery systems, the working fluid must flow at an adequate pressure and mass flow rate to rotate the turbine blades.

[0007] However, in a conventional waste heat recovery system in which the first and second nozzles have the same geometric configuration, there is only a narrow window range of working fluid pressure and mass flow rate in which the waste heat recovery system can operate. Specifically, the heat generated by the ICE varies based on the speed and load of the ICE. Thus, at a particular operating condition of the ICE (e.g., start-up), the heat generated by the ICE can cause the working fluid pressure and mass flow rate to fall outside the narrow window range in which the waste heat recovery system can operate. When the working fluid falls outside the narrow window range of pressure and mass flow rate, the working fluid must bypass the turbine expander or the turbine expander must be shut off to prevent condensation damage of the working fluid to the turbine blades.

[0008] Conventional nozzle assemblies are also difficult to manufacture: in particular, defining the nozzles in nozzle components that are integral with the nozzle block requires extensive and precise machining due to the size of the nozzle block, increasing manufacturing time and costs.

[0009] Thus, there remains a need to provide an improved waste heat recovery system. Summary of the Invention

[0010] A waste heat recovery system for recovering waste heat from an internal combustion engine includes a turbine expander for outputting power based on a working fluid. The turbine expander 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 to rotate the turbine blades. The nozzle assembly includes a nozzle block disposed about the shaft and adjacent to the turbine blades, a first nozzle component coupled to the nozzle block for accelerating the working fluid, and a second nozzle component coupled to the nozzle block for accelerating the working fluid. The first nozzle component defines a first nozzle having a first geometric configuration. The second nozzle component defines a second nozzle having a second geometric configuration different from the first geometric configuration. The waste heat recovery system also includes a flow control device in fluid communication with the turbine expander for directing the working fluid to at least one of the first and second nozzles or for bypassing the turbine expander. The waste heat recovery system further includes a controller in communication with the flow control device and adapted to control the flow control device to direct the working fluid to at least one of the first and second nozzles or to bypass the turbine expander.

[0011] A waste heat recovery system for recovering waste heat from an internal combustion engine includes a turbine expander for outputting power based on a working fluid. The turbine expander 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 to rotate the turbine blades. The nozzle assembly includes a nozzle block disposed about the shaft and adjacent to the turbine blades, the nozzle block defining a bore. The nozzle assembly also includes a nozzle component removably coupled to the nozzle block such that the nozzle component is selectively disposed within the bore to accelerate the working fluid. The nozzle component defines a nozzle. The waste heat recovery system also includes a flow control device in fluid communication with the turbine expander for directing the working fluid to the nozzle or to bypass the turbine expander. The waste heat recovery system further includes a controller in communication with the flow control device and adapted to control the flow control device to direct the working fluid to the nozzle or to bypass the turbine expander. In a turbine expander such as that described above, at least a portion of the nozzle block may be disposed between the nozzle and the turbine blades.

[0012] Thus, a waste heat recovery system having first and second nozzles with different geometric configurations can increase the operating range of the waste heat recovery system by allowing the working fluid to pass through each of the first and second nozzles at different working fluid pressures and mass flow rates. Also, the first and second nozzles provide a series of incremental steps for the working fluid pressure and mass flow rate that allows for greater controllability of the waste heat recovery system. Furthermore, a waste heat recovery system having a nozzle component removably coupled to a nozzle block reduces the manufacturing complexity of the waste heat recovery system. In particular, the nozzle of the nozzle component can be machined independently of the nozzle block, thereby reducing manufacturing time and manufacturing costs. [Brief description of the drawings]

[0013] Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings. [Figure 1] FIG. 1 is a schematic diagram of a waste heat recovery system including a turbine expander, a flow control device, a controller, an evaporator, a condenser, a sensor, and a pump. [Diagram 2] FIG. 2 is a perspective view of the turbine expander. [Diagram 3] FIG. 3 is a perspective view of the turbine expander of FIG. 2, in which the turbine expander includes turbine blades rotatable by a working fluid, a shaft coupled to and rotatable by the turbine blades, and a nozzle assembly for directing the working fluid to the turbine blades to rotate the turbine blades. [Figure 4] FIG. 4 is a top view of the turbine expander of FIG. 2 with the turbine housing removed and the turbine blades and shaft shown in phantom. [Diagram 5] FIG. 5 is a plan view of the nozzle assembly of FIGS. 2-4, in which the nozzle assembly includes a nozzle block, a first nozzle component coupled to the nozzle block to define a first nozzle shown in phantom lines, a second nozzle component coupled to the nozzle block to define a second nozzle shown in phantom lines, a third nozzle component coupled to the nozzle block to define a third nozzle shown in phantom lines, and a fourth nozzle component coupled to the nozzle block to define a fourth nozzle shown in phantom lines. [Figure 6A] FIG. 6A is a cross-sectional view of the first nozzle component taken along line 6A-6A of FIG. [Figure 6B] FIG. 6B is a cross-sectional view of the second nozzle component taken along line 6B-6B of FIG. [Figure 6C] FIG. 6C is a cross-sectional view of the third nozzle component taken along line 6C-6C of FIG. [Figure 6D] FIG. 6D is a cross-sectional view of the fourth nozzle component taken along line 6D-6D of FIG. [Figure 7A] FIG. 7A is a cross-sectional view of the first throat section of the first nozzle taken along line 7A-7A of FIG. 6A. [Figure 7B] FIG. 7B is a cross-sectional view of the second throat of the second nozzle taken along line 7B-7B of FIG. 6B. [Figure 7C] FIG. 7C is a cross-sectional view of the third throat of the third nozzle taken along line 7C-7C of FIG. 6C. [Figure 7D] FIG. 7D is a cross-sectional view of the fourth throat of the fourth nozzle taken along line 7D-7D of FIG. 6D. [Figure 8] FIG. 8 is a perspective view of an alternative embodiment of the nozzle assembly of FIGS. 2-5, in which a nozzle block defines first, second, third, and fourth bores, the first, second, third, and fourth nozzle components are removably coupled to the nozzle block, the first, second, third, and fourth nozzles are shown in phantom lines, and the first, second, third, and fourth nozzle components are disposed within the first, second, third, and fourth bores, respectively. [Figure 9] FIG. 9 is a perspective view of the nozzle assembly of FIG. 8 with the first, second, third, and fourth nozzle components removed from the first, second, third, and fourth bores, respectively. [Figure 10] FIG. 10 is a perspective view of the turbine expander of FIG. 2 further including a plurality of fluid couplers coupled to the first, second, third, and fourth nozzle components. [Figure 11] 11 is a perspective view of the turbine expander of FIG. 10 with the plurality of fluid coupling couplers removed from the first, second, third, and fourth nozzle components. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Referring to the drawings, where like numerals indicate like parts throughout the several views, a waste heat recovery system 20 for recovering waste heat from an internal combustion engine (ICE) is shown generally in Figure 1. The waste heat recovery system 20 includes a turbine expander 22 for outputting power based on a working fluid, a flow control device 24 in fluid communication with the turbine expander 22, and a controller 26 in communication with the flow control device 24.

[0015] With reference to Figure 3, the turbine expander 22 includes turbine blades 28 that are rotatable by the working fluid. As best shown in Figure 2, the turbine expander 22 also includes a shaft 30 that is coupled to and rotatable by the turbine blades 28. The shaft 30 extends along a longitudinal axis A. The working fluid rotates the turbine blades 28 about the longitudinal axis A of the shaft 30.

[0016] With continued reference to FIG. 2, the turbine expander 22 further includes a nozzle assembly 32 for directing the working fluid to the turbine blades 28 to rotate the turbine blades 28. The nozzle assembly 32 includes a nozzle block 34 disposed about the shaft 30 and adjacent the turbine blades 28. Typically, the nozzle block 34 has an annular configuration. However, the nozzle block 34 may have any configuration suitable for directing the working fluid to the turbine blades 28. The nozzle block 34 may have a first face 36 that faces the turbine blades 28, as best shown in FIG. 4, and a second face 38 that faces the first face 36, as best shown in FIG. 2.

[0017] With continued reference to Figure 2, the nozzle assembly 32 also includes a nozzle component 40 coupled to the nozzle block 34 for accelerating the working fluid. As shown in Figures 5 and 6A, the nozzle component 40 defines a nozzle 42. In one embodiment, the nozzle component 40 is integral (i.e., one piece) with the nozzle block 34, as shown in Figure 2. In another embodiment, the nozzle component 40 may be separate (i.e., may not be integral) from the nozzle block 34, as described in more detail below.

[0018] The nozzle 42 has a geometric configuration. The geometric configuration can be a converging-type configuration, a diverging-type configuration, or a de Laval convergent-divergent configuration. Typically, the geometric configuration is a de Laval configuration, as shown in Figures 5 and 6A.

[0019] As best shown in FIG. 6A, when the geometric configuration of the nozzle 42 is a DeLaval configuration, the nozzle 42 may include a working fluid inlet 44, a converging section 46, a diverging section 48, a throat section 50 separating the converging section 46 from the diverging section 48, and a working fluid outlet 52. If present, the converging section 46 extends from the working fluid inlet 44 to the throat section 50. If present, the convergent section 46, the cross-sectional area of ​​the nozzle 42 gradually decreases from the working fluid inlet 44 to the throat section 50. If present, the diverging section 48 extends from the throat section 50 to the working fluid outlet 52. If present, the diverging section 48, the cross-sectional area of ​​the nozzle 42 gradually increases from the throat section 50 to the working fluid outlet 52. If present, the throat section 50 is where the cross-sectional area of ​​the nozzle 42 is at a minimum. In the context of this disclosure, the smallest cross-sectional area of ​​nozzle 42 is referred to as the throat area 54, as best shown in FIG. 7A.

[0020] The working fluid passes through the converging section 46 of the nozzle 42 to the throat section 50. If the working fluid has the proper pressure and mass flow rate, the working fluid velocity will be choke at the throat section 50. Whether the working fluid is at the proper pressure and mass flow rate for the working fluid velocity to be choked at the throat section 50 is based on the throat cross-sectional area 54. The working fluid then expands in the diverging section 48 increasing the working fluid velocity to supersonic speeds. In this manner, the nozzle 42 accelerates the working fluid to supersonic speeds.

[0021] As mentioned above, the nozzle component 40 may be integral with the nozzle block 34. In other embodiments, the nozzle component 40 may be secured to the nozzle block 34, for example, by welding. As shown in FIGS. 8 and 9, the nozzle component 40 may be removably coupled to the nozzle block 34. When the nozzle component 40 is removably coupled to the nozzle block 34, the nozzle block 34 may define a bore 56 for selectively receiving the nozzle component 40. In this manner, the nozzle component 40 may be selectively positioned within the bore 56. Advantageously, when the nozzle component 40 is removably coupled to the nozzle block 34, the manufacturing complexity of the waste heat recovery system 20 is reduced. In particular, the nozzle 42 of the nozzle component 40 may be machined and / or cast independently of the nozzle block 34, thereby reducing manufacturing time and costs. A removably coupled nozzle component 40 may also allow for greater customizability of the waste heat recovery system 20 due to interchangeability of the nozzle component 40.

[0022] If the nozzle component 40 is removably coupled to the nozzle block 34, the nozzle component may include threads. The nozzle block 34 may also include threads such that the nozzle component may be removably coupled to the nozzle block 34. In other embodiments, the nozzle component 40 may be removably coupled to the nozzle block 34 by a transition fit or an interference fit.

[0023] In some embodiments, when the nozzle component 40 is removably coupled to the nozzle block 34, at least a portion of the nozzle block 34 is disposed between the nozzles 42 and the turbine blades 28, as shown in Figures 8 and 9. In other embodiments, the nozzle block 34 is disposed entirely between the nozzles 42 and the turbine blades 28. In some embodiments, no portion of the nozzle block 34 is disposed between the nozzles 42 and the turbine blades 28.

[0024] Nozzle component 40 may be further defined as a first nozzle component 40, and nozzle 42 may be further defined as a first nozzle 42. Additionally, each portion of nozzle 42 described above may be further defined as a first portion (e.g., first throat portion 50, first throat cross-sectional area 54, etc.).

[0025] 2, the nozzle assembly 32 may also include a second nozzle component 58 coupled to the nozzle block 34 for accelerating the working fluid. As shown in FIGS. 5 and 6B, when present, the second nozzle component 58 defines a second nozzle 60. In one embodiment, as best shown in FIG. 2, the second nozzle component 58 is integral (i.e., one piece) with the nozzle block 34. In another embodiment, as described in more detail below, the second nozzle component 58 may be separate (i.e., may not be integral) from the nozzle block 34.

[0026] The second nozzle 60 has a second geometric configuration. The second geometric configuration can be a convergent configuration, a divergent configuration, or a DeLaval (converging-diverging) configuration. Typically, the second geometric configuration is a DeLaval configuration as shown in Figures 5 and 6B. When the second geometric configuration is a DeLaval configuration, the second nozzle 60 can have a second working fluid inlet 62, a second converging section 64, a second diverging section 66, a second throat section 68 separating the second converging section 64 from the second diverging section 66, and a second working fluid outlet 70. As best shown in Figure 7B, the smallest cross-sectional area of ​​the second nozzle 60 is referred to as the second throat cross-sectional area 72. It should be inferred that the descriptions of the first working fluid inlet 44, the first converging section 46, the first diverging section 48, the first throat section 50, and the first working fluid outlet 52 also apply to the second working fluid inlet 62, the second converging section 64, the second diverging section 66, the second throat section 68, and the second working fluid outlet 70.

[0027] In one embodiment, the second geometric configuration of the second nozzle 60, if present, is different from the first geometric configuration of the first nozzle 42. In some embodiments, the first and second geometric configurations can be different types of configurations. For example, the first geometric configuration can be a convergent configuration and the second geometric configuration can be a DeLaval configuration. In other embodiments, as shown in FIG. 5, the first and second geometric configurations can be the same type of configuration but have corresponding portions that differ from each other. For example, if the first and second geometric configurations are DeLaval configurations, at least one of the first working fluid inlet 44, first convergent section 46, first throat section 50, first divergent section 48, and first working fluid outlet 52 of the first nozzle 42 is different from the corresponding second working fluid inlet 62, second convergent section 64, second throat section 68, second divergent section 66, and second working fluid outlet 70 of the second nozzle 60.

[0028] In some embodiments, when the first and second geometric configurations are DeLaval configurations, the second throat cross-sectional area 72 is different from the first throat cross-sectional area 54, as shown in Figures 7A and 7B. As described above, whether the velocity of the working fluid is choked at the first and second throat sections 50, 68 is determined by the first and second throat cross-sectional areas 54, 72 and the working fluid pressure and mass flow rate. Because the first and second throat cross-sectional areas 54, 72 are different, the working fluid pressure and mass flow rate may be suitable for one of the first and second nozzles 42, 60 to accelerate the working fluid to supersonic speed, and the other one of the first and second nozzles 42, 60 may not be suitable. Furthermore, during operation of the ICE, the heat recovered by the waste heat recovery system 20 may change the working fluid pressure and mass flow rate such that both the first and second nozzles 42, 60 can accelerate the working fluid to supersonic speed. In this manner, the first and second nozzles 42, 60 increase the operating range of the waste heat recovery system 20. Specifically, the first and second nozzles 42, 60 increase the range of working fluid mass flow rates at which the waste heat recovery system 20 may operate for a particular working fluid pressure. This advantageously allows the waste heat recovery system 20 to maintain maximum cycle efficiency and power output over a wider range of ICE operating conditions, as described in further detail below.

[0029] As shown in FIG. 2 and described above, the second nozzle component 58 may be integral with the nozzle block 34. In other embodiments, the second nozzle component 58 may be secured to the nozzle block 34, for example, by welding. As shown in FIGS. 8 and 9, in yet other embodiments, the second nozzle component 58 may be removably coupled to the nozzle block 34. When the second nozzle component 58 is removably coupled to the nozzle block 34, the nozzle block may define a second bore 74 for selectively receiving the second nozzle component 58. In this manner, the second nozzle component 58 may be selectively positioned within the second bore 74.

[0030] When the second nozzle component 58 is removably coupled to the nozzle block 34, the second nozzle component may include threads. The nozzle block 34 may also include threads such that the second nozzle component 58 may be removably coupled to the nozzle block 34. In other embodiments, the second nozzle component 58 may be removably coupled to the nozzle block 34 by an transition fit or an interference fit.

[0031] In some embodiments, when the second nozzle component 58 is removably coupled to the nozzle block 34, at least a portion of the nozzle block 34 is disposed between the second nozzle 60 and the turbine blades 28, as shown in Figures 8 and 9. In other embodiments, the nozzle block 34 is disposed entirely between the second nozzle 60 and the turbine blades 28. In some embodiments, no portion of the nozzle block 34 is disposed between the second nozzle 60 and the turbine blades 28.

[0032] In some embodiments, the first and second nozzle components 42, 60 may be circumferentially spaced apart about the longitudinal axis A. In other embodiments, the first and second nozzle components 42, 60 may be circumferentially spaced apart equally about the longitudinal axis A.

[0033] Referring again to FIG. 2, the nozzle assembly 32 may also include a third nozzle component 76 coupled to the nozzle block 34 for accelerating the working fluid. When present, the third nozzle component 76 defines a third nozzle 78. In one embodiment, as best shown in FIG. 2, the third nozzle component 76 is integral (i.e., one piece) with the nozzle block 34. In another embodiment, as described in more detail below, the third nozzle component 76 may be separate (i.e., may not be integral) from the nozzle block 34.

[0034] The third nozzle 78 has a third geometric configuration. The third geometric configuration can be a convergent configuration, a divergent configuration, or a DeLaval convergent-divergent configuration. Typically, the third geometric configuration is a DeLaval configuration, as shown in Figures 5 and 6C. When the third geometric configuration is a DeLaval configuration, the third nozzle 78 can have a third working fluid inlet 80, a third convergent section 82, a third divergent section 84, a third throat section 86 separating the third convergent section 82 from the third divergent section 84, and a third working fluid outlet 88. As shown in Figure 7C, the smallest cross-sectional area of ​​the third nozzle 78 is referred to as a third throat cross-sectional area 90. It should be inferred that the descriptions of the first working fluid inlet 44, the first converging section 46, the first diverging section 48, the first throat section 50, and the first working fluid outlet 52 also apply to the third working fluid inlet 80, the third converging section 82, the third diverging section 84, the third throat section 86, and the third working fluid outlet 88.

[0035] The third geometric configuration of the third nozzle 78, if present, is different from at least one of the first and second geometric configurations of the first and second nozzles 42, 60. In some embodiments, the third geometric configuration can be a different type of configuration than at least one of the first and second geometric configurations. For example, the first geometric configuration can be a convergent configuration, the second geometric configuration can be a DeLaval configuration, and the third geometric configuration can be a DeLaval configuration. In other embodiments, as shown in FIG. 5, the first, second, and third geometric configurations can be the same type of configuration but have corresponding portions that differ from one another. For example, when the first, second, and third geometric configurations are DeLaval configurations, at least one of the third working fluid inlet 80, the third convergent portion 82, the third divergent portion 84, the third throat portion 86, the third divergent portion 84, and the third working fluid outlet 88 of the third nozzle 78 are different from the corresponding first working fluid inlet 44, the first convergent portion 46, the first divergent portion 48, the first throat portion 50, and the first working fluid outlet 52 of the first nozzle 42 and / or the second working fluid inlet 62, the second convergent portion 64, the second divergent portion 66, the second throat portion 68, and the second working fluid outlet 70 of the second nozzle 60.

[0036] In some embodiments, when the first, second, and third geometric configurations are DeLaval configurations, the third throat cross-sectional area 90 is different from at least one of the first and second throat cross-sectional areas 54, 72. In other embodiments, when the first, second, and third geometric configurations are DeLaval configurations, the first, second, and third throat cross-sectional areas 54, 72, 90 are different from one another, as shown in Figures 7A-7C.

[0037] If the nozzle geometric configurations are different from each other, the number of nozzle combinations through which the working fluid can pass before rotating the turbine blades 28 is 2 n −1, where n is the number of nozzles contained within the nozzle assembly 32.

[0038] When the first, second, and third geometric configurations are different from one another, the working fluid may pass through seven different combinations of the first, second, and third nozzles 42, 60, 78 before rotating the turbine blades 28 based on the working fluid pressure and mass flow rate. Specifically, the working fluid may pass only through the first nozzle 42, only through the second nozzle 60, only through the third nozzle 78, only through the first and second nozzles 42, 60, only through the first and third nozzles 42, 78, only through the second and third nozzles 60, 78, and only through the first, second, and third nozzles 42, 60, 78.

[0039] If the first, second and third geometric configurations are DeLaval configurations and the first, second and third throat cross-sectional areas 54, 72, 90 are different from each other, whether the velocity of the working fluid is choked at the first, second and third throats 50, 68, 86 is determined by the first, second and third throat cross-sectional areas 54, 72, 90 and the working fluid pressure and mass flow rate, as described above. Because the first, second and third throat cross-sectional areas 54, 72, 90 are different, the working fluid pressure and mass flow rate may be suitable for one of the first, second and third nozzles 42, 60, 78 to accelerate the working fluid to supersonic speed, and the other one of the first, second and third nozzles 42, 60, 78 may not be suitable. Additionally, during operation of the ICE, the heat recovered by the waste heat recovery system 20 can vary the working fluid pressure and mass flow rate such that different combinations of the first, second, and third nozzles 42, 60, 78 can accelerate the working fluid to supersonic speeds. In this manner, the first, second, and third nozzles 42, 60, 78 increase the operating range of the waste heat recovery system 20. Specifically, the first, second, and third nozzles 42, 60, 78 increase the range of working fluid mass flow rates at which the waste heat recovery system 20 can operate for a particular working fluid pressure. This advantageously allows the waste heat recovery system 20 to maintain maximum cycle efficiency and power output for a wider range of ICE operating conditions, as described in further detail below.

[0040] As shown in FIG. 2 and described above, the third nozzle component 76 may be integral with the nozzle block 34. In other embodiments, the third nozzle component 76 may be secured to the nozzle block 34, for example, by welding. As shown in FIGS. 8 and 9, in yet other embodiments, the third nozzle component 76 may be removably coupled to the nozzle block 34. When the third nozzle component 76 is removably coupled to the nozzle block 34, the nozzle block may define a third bore 92 for selectively receiving the third nozzle component 76. In this manner, the third nozzle component 76 may be selectively positioned within the third bore 92.

[0041] If the third nozzle component 76 is removably coupled to the nozzle block 34, the third nozzle component 76 may include threads. The nozzle block 34 may also include threads such that the third nozzle component 76 may be removably coupled to the nozzle block 34. In other embodiments, the third nozzle component 76 may be removably coupled to the nozzle block 34 by an transition fit or an interference fit.

[0042] In some embodiments, when the third nozzle component 76 is removably coupled to the nozzle block 34, at least a portion of the nozzle block 34 is disposed between the third nozzle 78 and the turbine blades 28, as shown in Figures 8 and 9. In other embodiments, the nozzle block 34 is disposed entirely between the third nozzle 78 and the turbine blades 28. In some embodiments, no portion of the nozzle block 34 is disposed between the third nozzle 78 and the turbine blades 28.

[0043] In some embodiments, the first, second, and third nozzle components 40, 58, 76 may be circumferentially spaced about the longitudinal axis A. In other embodiments, the first, second, and third nozzle components 40, 58, 76 may be equally circumferentially spaced about the longitudinal axis A.

[0044] Referring again to FIG. 2, the nozzle assembly 32 may also include a fourth nozzle component 94 coupled to the nozzle block 34 for accelerating the working fluid. When present, the fourth nozzle component 94 defines a fourth nozzle 96. In one embodiment, as best shown in FIG. 2, the fourth nozzle component 94 is integral (i.e., one piece) with the nozzle block 34. In another embodiment, as described in more detail below, the fourth nozzle component 94 may be separate (i.e., may not be integral) from the nozzle block 34.

[0045] The fourth nozzle 96 has a fourth geometric configuration. The fourth geometric configuration may be a convergent configuration, a divergent configuration, or a DeLaval (converging-diverging) configuration. Typically, the fourth geometric configuration is a DeLaval configuration as shown in FIG. 5 and FIG. 6D. When the fourth geometric configuration is a DeLaval configuration, the fourth nozzle 96 may have a fourth working fluid inlet 98, a fourth converging section 100, a fourth diverging section 102, a fourth throat section 104 separating the fourth converging section 100 from the fourth diverging section 102, and a fourth working fluid outlet 106. As shown in FIG. 7C, the smallest cross-sectional area of ​​the fourth nozzle 96 is referred to as a fourth throat cross-sectional area 108. It should be inferred that the descriptions of the first working fluid inlet 44, the first converging section 46, the first diverging section 48, the first throat section 50, and the first working fluid outlet 52 also apply to the fourth working fluid inlet 98, the fourth converging section 100, the fourth diverging section 102, the fourth throat section 104, and the fourth working fluid outlet 106.

[0046] The fourth geometric configuration of the fourth nozzle 96, if present, is different from at least one of the first, second, and third geometric configurations of the first, second, and third nozzles 42, 60, 78. In some embodiments, the fourth geometric configuration can be a different type of configuration than at least one of the first, second, and third geometric configurations. For example, the first geometric configuration can be a convergent configuration, the second geometric configuration can be a DeLaval configuration, the third geometric configuration can be a DeLaval configuration, and the fourth geometric configuration can be a divergent configuration. In other embodiments, as shown in FIG. 5, the first, second, third, and fourth geometric configurations can be the same type of configuration but have corresponding portions that differ from one another. For example, when the first, second, third, and fourth geometric configurations are DeLaval configurations, at least one of the fourth working fluid inlet 98, fourth convergent portion 100, fourth divergent portion 102, fourth throat portion 104, and fourth working fluid outlet 106 of the fourth nozzle 96 is different from the corresponding first working fluid inlet 44, first convergent portion 46, first divergent portion 48, first throat portion 50, and first working fluid outlet 52 of the first nozzle 42, the second working fluid inlet 62, second convergent portion 64, second divergent portion 66, second throat portion 68, and second working fluid outlet 70 of the second nozzle 60, and / or the third working fluid inlet 80, third convergent portion 82, third divergent portion 84, third throat portion 86, and third working fluid outlet 88 of the third nozzle 78.

[0047] In some embodiments, when the first, second, third, and fourth geometric configurations are DeLaval configurations, the fourth throat cross-sectional area 108 is different from at least one of the first, second, and third throat cross-sectional areas 54, 72, 90. In other embodiments, when the first, second, third, and fourth geometric configurations are DeLaval configurations, the first, second, third, and fourth throat cross-sectional areas 54, 72, 90, 108 are different from one another, as shown in Figures 7A-7D.

[0048] When the first, second, third, and fourth geometric configurations are different from one another, the working fluid may pass through fifteen different combinations of the first, second, third, and fourth nozzles 42, 60, 78, 96 before rotating the turbine blades 28 based on the working fluid pressure and mass flow rate. Specifically, the working fluid can pass only through the first nozzle 42, only through the second nozzle 60, only through the third nozzle 78, only through the fourth nozzle 96, only through the first and second nozzles 42, 60, only through the first and third nozzles 42, 78, only through the first and fourth nozzles 42, 96, only through the second and third nozzles 60, 78, only through the second and fourth nozzles 60, 96, only through the third and fourth nozzles 78, 96, only through the first, second and third nozzles 42, 60, 78, only through the first, third and fourth nozzles 42, 78, 96, only through the second, third and fourth nozzles 60, 78, 96, and only through the first, second, third and fourth nozzles 42, 60, 78, 96.

[0049] When the first, second, third and fourth geometric configurations are DeLaval configurations and the first, second, third and fourth throat cross-sectional areas 54, 72, 90, 108 are different from each other, whether the velocity of the working fluid is choked at the first, second, third and fourth throats 50, 68, 86, 104 is determined by the first, second, third and fourth throat cross-sectional areas 54, 72, 90, 108 and the working fluid pressure and mass flow rate as described above. Because the first, second, third and fourth throat cross-sectional areas 54, 72, 90, 108 are different, the working fluid pressure and mass flow rate may be suitable for one of the first, second, third and fourth nozzles 54, 72, 90, 108 to accelerate the working fluid to supersonic speed, and the other one of the first, second, third and fourth nozzles 54, 72, 90, 108 may not be suitable. Additionally, during operation of the ICE, the heat recovered by the waste heat recovery system 20 can vary the working fluid pressure and mass flow rate such that different combinations of the first, second, third, and fourth nozzles 42, 60, 78, 96 can accelerate the working fluid to supersonic speeds. In this manner, the first, second, third, and fourth nozzles 42, 60, 78, 96 increase the operating range of the waste heat recovery system 20. Specifically, the first, second, third, and fourth nozzles 42, 60, 78, 96 increase the range of working fluid mass flow rates at which the waste heat recovery system 20 can operate for a particular working fluid pressure. This advantageously allows the waste heat recovery system 20 to maintain maximum cycle efficiency and power output for a wider range of ICE operating conditions, as described in further detail below.

[0050] 2 and described above, the fourth nozzle component 94 may be integral with the nozzle block 34. In other embodiments, the fourth nozzle component 94 may be secured to the nozzle block 34, for example, by welding. As shown in FIGS. 8 and 9, in yet other embodiments, the third nozzle component 76 may be removably coupled to the nozzle block 34. When the fourth nozzle component 94 is removably coupled to the nozzle block 34, the nozzle block 34 may define a fourth bore 110 for selectively receiving the third nozzle component 76. In this manner, the fourth nozzle component 94 may be selectively positioned within the fourth bore 110.

[0051] When the fourth nozzle component 94 is removably coupled to the nozzle block 34, the fourth nozzle component 94 may include threads. The nozzle block 34 may also include threads such that the fourth nozzle component 94 may be removably coupled to the nozzle block 34. In other embodiments, the fourth nozzle component 94 may be removably coupled to the nozzle block 34 by an transition fit or an interference fit.

[0052] In some embodiments, when the fourth nozzle component 94 is removably coupled to the nozzle block 34, at least a portion of the nozzle block 34 is disposed between the fourth nozzle 96 and the turbine blades 28, as shown in Figures 8 and 9. In other embodiments, the nozzle block 34 is disposed entirely between the fourth nozzle 96 and the turbine blades 28. In some embodiments, no portion of the nozzle block 34 is disposed between the fourth nozzle 96 and the turbine blades 28.

[0053] In some embodiments, the first, second, third, and fourth nozzle components 40, 58, 76, 94 may be circumferentially spaced about the longitudinal axis A. In other embodiments, the first, second, third, and fourth nozzle components 40, 58, 76, 94 may be equally circumferentially spaced about the longitudinal axis A, as shown in FIG.

[0054] The nozzle assembly 32 may further include any number of additional nozzle components, and it should be inferred that the description of the first nozzle component 40 is applicable to any additional nozzle components. Furthermore, it should be inferred that any geometric configuration of any nozzle defined by the additional nozzle components is different from at least one of the nozzles included in the nozzle assembly. In this manner, the operating range of the waste heat recovery system 20 may be further expanded by including additional nozzle components beyond the first, second, third, and / or fourth nozzle components 40, 58, 76, 94 described herein. For example, the nozzle assembly 32 may include five, six, seven, or eight nozzle components. However, it should be inferred that the nozzle assembly 32 may have more than eight nozzle components.

[0055] 2 and 3, the turbine expander 22 may include a turbine housing 112. If present, the turbine blades 28 may be disposed within the turbine housing 112.

[0056] 1 , the waste heat recovery system 20 includes a flow control device 24 in fluid communication with the turbine expander 22 to direct a working fluid to at least one of the first, second, third, and / or fourth nozzles 42, 60, 78, 96 contained within the turbine expander 22 or to bypass the turbine expander 22. The flow control device 24 may be a valve or any other suitable working fluid flow control device. The flow control device 24 is typically located upstream of the turbine expander 22.

[0057] In some embodiments, the flow control device 24 may include a plurality of valves corresponding to each nozzle included in the turbine expander 22. For example, if the turbine expander 22 includes two nozzles, the flow control device 24 may include two valves. Each valve may be movable between an open position in which the working fluid may flow to the corresponding nozzle and a closed position in which the working fluid is restricted from flowing to the corresponding nozzle. If the flow control device 24 includes a plurality of valves corresponding to each nozzle included in the turbine expander, the flow control device 24 may also include a bypass valve that allows the working fluid to bypass the turbine expander 22. In other embodiments, the flow control device may include a switching valve adapted to selectively direct the working fluid to one or more of the nozzles included in the turbine expander 22 or to bypass the turbine expander 22. It should be inferred that any valve of the flow control device 24 may be movable between a closed position, an open position, and an intermediate position in which the flow of the working fluid is measured.

[0058] With continued reference to FIG. 1, the waste heat recovery system 20 includes a controller 26 in communication with the flow control device 24 and adapted to control the flow control device 24 to direct the working fluid to at least one of the first, second, third and / or fourth nozzles 42, 60, 78, 96 contained within the turbine expander 22 or to bypass the turbine expander 22.

[0059] Controller 26 may include one or more processors, or microprocessors, for processing instructions stored in memory to control the operation of flow control device 24. Such instructions may be any of the functions, algorithms, or techniques described herein that are executed by controller 26. Additionally or alternatively, controller 26 may include one or more microcontrollers, field programmable gate arrays, systems on a chip, discrete circuits, and / or other suitable hardware, software, or firmware capable of performing the functions described herein.

[0060] Typically, the working fluid is an organic high molecular weight working fluid that has a liquid-vapor phase change that occurs at a lower temperature than the water-steam phase change. The working fluid may include at least one of ethanol, methanol, kerosene, gasoline, diesel, propanol, butanol, water, benzene, toluene, methane, ethane, propane, butane, acetone, or liquid hydrogen. During operation of the waste heat recovery system, the working fluid is in one of a liquid state or a vapor state. In the vapor state, the working fluid is more suitable for rotating the turbine blades.

[0061] 1, the waste heat recovery system 20 may also include an evaporator 114 in fluid communication with the flow control device 24 and the turbine expander 22. The evaporator 114 transfers heat rejected by the ICE to the working fluid, causing the working fluid to change phase from a liquid state to a vapor state. If present, the evaporator 114 is disposed upstream of the flow control device 24.

[0062] The waste heat recovery system 20 may also include a condenser 116 in fluid communication with the turbine expander 22 and the flow control device 24. The condenser 116 condenses the working fluid from a vapor state to a liquid state after the working fluid passes through the turbine expander 22. The condenser 116 is disposed downstream of the turbine expander 22. In some embodiments, if the waste heat recovery system 20 includes an evaporator 114, the condenser 116 is disposed downstream of the turbine expander 22 and upstream of the evaporator 114.

[0063] The waste heat recovery system 20 may further include at least one sensor 118 in communication with the controller 26. The at least one sensor 118 is adapted to detect a property of the working fluid. If present, the at least one sensor 118 is disposed upstream of the flow control device 24 and the turbine expander 22, such that the at least one sensor 118 can detect a property of the working fluid before the working fluid passes through the flow control device 24. As shown in FIG. 1, when the evaporator 114 is included in the waste heat recovery system 20, the at least one sensor 118 is disposed upstream of the flow control device 24 and downstream of the evaporator 114. However, the at least one sensor 118 may be disposed upstream of the evaporator 114 or at any other location suitable for detecting a property of the working fluid. The at least one sensor 118 is further adapted to transmit a signal to the controller 26 indicative of the property of the working fluid detected by the at least one sensor 118. The property of the working fluid detected by the at least one sensor 118 may be a working fluid pressure, a working fluid mass flow rate, a working fluid temperature, a working fluid quality, and combinations thereof. In some embodiments, at least one sensor 118 detects the working fluid temperature and the working fluid pressure.

[0064] In some embodiments, the at least one sensor 118 can be two sensors. When the at least one sensor 118 is two sensors, each sensor can detect one of the working fluid properties described above. Alternatively, each sensor can detect a combination of the working fluid properties described above. In some embodiments, one sensor detects working fluid temperature and the other sensor detects working fluid pressure.

[0065] To ensure maximum cycle efficiency and power output of the waste heat recovery system 20, the combination of the first, second, third, and / or fourth nozzles 42, 60, 78, 96 through which the working fluid passes before rotating the turbine blades 28 is based on a function of working fluid pressure and working fluid mass flow rate. As described above, heat rejected by the ICE is recovered by the waste heat recovery system 20 to heat the working fluid, which undergoes a liquid-vapor phase change. The heat rejected by the ICE varies based on the speed and load (i.e., operating condition) of the ICE. Thus, at a particular operating condition (e.g., start-up, acceleration, etc.) of the ICE, the heat rejected by the ICE and recovered by the waste heat recovery system 20 may provide a working fluid pressure that is not suitable for one or more of the first, second, third, and / or fourth nozzles 42, 60, 78, 96 if maximum cycle efficiency and power output of the waste heat recovery system 20 is to be maintained. As described below, the at least one sensor 118 communicates with the controller 26 to direct fluid to at least one of the first, second, third and / or fourth nozzles 42, 60, 78, 96 contained within the turbine expander 22 to ensure maximum cycle efficiency and power output of the waste heat recovery system 20 over a wider range of ICE operating conditions.

[0066] When at least one sensor 118 is included within the waste heat recovery system 20, the controller 26 may be adapted to control the flow control device 24 to direct the working fluid to at least one of the first, second, third, and / or fourth nozzles 42, 60, 78, 96 included within the turbine expander 22 or to bypass the turbine expander 22 based on a property of the working fluid detected by the at least one sensor 118. In one embodiment, when the controller 26 receives a signal indicative of a property of the working fluid detected by the at least one sensor 118, the controller 26 may compare the detected property of the working fluid to a threshold value corresponding to a geometric configuration of each of the first, second, third, and / or fourth nozzles 42, 60, 78, 96 included within the turbine expander. After comparing the detected characteristic of the working fluid to the threshold(s), the controller then controls the flow control device 24 to direct the working fluid to each of the first, second, third, and / or fourth nozzles 42, 60, 78, 96 where the detected characteristic of the working fluid exceeds the corresponding threshold(s). If the controller 26 determines that the corresponding threshold(s) is not exceeded by the detected characteristic of the working fluid, the controller 26 controls the flow control device 24 to direct the working fluid to bypass the turbine expander 22. In this manner, the different geometric configurations of the first, second, third, and / or fourth nozzles 42, 60, 78, 96 advantageously increase the operating range of the waste heat recovery system 20 by accelerating the working fluid to supersonic speeds over a wider range of working fluid pressures, mass flow rates, temperatures, etc. Additionally, the waste heat recovery system 20 advantageously allows for a gradual increase in the flow of the working fluid to the turbine blades 28 as the working fluid pressure and / or mass flow rate change during operation of the ICE.

[0067] For example, during start-up of the ICE, the working fluid mass flow rate may be low to ensure maximum transfer of heat rejected by the ICE to the working fluid. To ensure maximum cycle efficiency and power output of the waste heat recovery system 20, the working fluid pressure will typically have a higher value than when the engine is in other operating conditions, such as a steady-state operating condition. Based on the higher value of the working fluid pressure, the controller 26 will control the flow control device 24 to direct the working fluid to at least one of the first, second, third, and / or fourth nozzles 42, 60, 78, 96 having a smaller throat cross-sectional area.

[0068] In another embodiment, during acceleration, the heat rejected by the ICE changes constantly. To ensure maximum cycle efficiency and power output of the waste heat recovery system 20, the controller 26 controls the flow control device 24 to direct the working fluid to one, two, three, and / or four of the first, second, third, and / or fourth nozzles 42, 60, 78, 96 such that the working fluid pressure remains relatively constant while the heat rejected by the ICE changes. In other words, the number of nozzles through which the working fluid is directed can change as the heat rejected by the ICE changes.

[0069] In some embodiments, the at least one sensor 118 may be adapted to detect at least one of a working fluid temperature and a working fluid pressure of the working fluid upstream of the turbine expander 22. The controller 26 may control the flow control device 24 to direct the working fluid to at least one of the first, second, third, and / or fourth nozzles 42, 60, 78, 96 included within the turbine expander 22 or to bypass the turbine expander 22 based on the at least one of the working fluid mass flow rate and the working fluid pressure detected by the at least one sensor 118.

[0070] 1 , the waste heat recovery system 20 may also include a working fluid circuit 120 for circulating a working fluid. The working fluid circuit 120 fluidly couples the turbine expander 22, the flow control device 24, the evaporator 114, and / or the condenser 116. The working fluid circuit 120 may include a number of fluid conduits.

[0071] As shown in Figures 10 and 11, when the working fluid circuit 120 includes multiple fluid conduits, the turbine expander 22 may include one or more fluid couplers 122 for removably coupling one of the fluid conduits to each of the first, second, third, and / or fourth nozzle components 40, 58, 76, 94 included within the turbine expander 22.

[0072] In some embodiments, the working fluid circuit 120 may include a bypass loop that fluidly couples the flow control device 24 directly to the condenser 116 , thereby avoiding passage of the working fluid through the turbine expander 22 .

[0073] 1 , the waste heat recovery system 20 may also include a pump 124 adapted to adjust the working fluid flow rate through the waste heat recovery system 20 at one or more speeds. The pump 124 may be any suitable pump, such as a piston pump or a diaphragm pump. In some embodiments, when the waste heat recovery system 20 includes an evaporator 114 and a condenser 116, the pump 124 may be disposed upstream of the evaporator 114 and downstream of the condenser 116. In some embodiments, when at least one sensor 118 is present, the pump 124 may be in communication with the controller 26, which may control the pump 124 to adjust the working fluid flow rate based on the properties of the working fluid detected by the at least one sensor 118.

[0074] A vehicle may include the waste heat recovery system 20 described herein. In some embodiments, the shaft 30 of the turbine expander 22 may be coupled to an electrical generator. When the shaft 30 is coupled to a generator, waste heat generated by the ICE may be converted to electrical power that may be stored or used by the vehicle.

[0075] The invention has been described in an illustrative manner, and it should be understood that the terminology used is intended to be in the nature of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings, and the invention may be practiced in ways other than as specifically described.

Claims

1. 1. A turbine expander for a waste heat recovery system for outputting power based on a working fluid, comprising: a turbine blade rotatable by the working fluid; and 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 to rotate the turbine blades, the nozzle assembly comprising: a nozzle block disposed about the shaft and adjacent the turbine blades; a first nozzle component coupled to the nozzle block for accelerating the working fluid and defining a first nozzle having a first geometric configuration; and a second nozzle component coupled to the nozzle block for accelerating the working fluid, the second nozzle component defining a second nozzle having a second geometric configuration different from the first geometric configuration; the nozzle block further defining a first bore and a second bore, the first nozzle component being removably coupled to the nozzle block such that the first nozzle component is selectively disposed within the first bore, and the second nozzle component being removably coupled to the nozzle block such that the second nozzle component is selectively disposed within the second bore.

2. 2. The turbine expander of claim 1, wherein the first geometric configuration of the first nozzle is a DeLaval configuration having a first throat cross-sectional area and the second geometric configuration of the second nozzle is a DeLaval configuration having a second throat cross-sectional area different than the first throat cross-sectional area.

3. 3. The turbine expander of claim 1, wherein the nozzle assembly further includes a third nozzle component coupled to the nozzle block for accelerating the working fluid, the third nozzle component defining a third nozzle having a third geometric configuration different from at least one of the first and second geometric configurations.

4. 4. The turbine expander of claim 3, wherein the nozzle assembly further includes a fourth nozzle component coupled to the nozzle block for accelerating the working fluid, the fourth nozzle component defining a fourth nozzle having a fourth geometric configuration different from at least one of the first, second, and third geometric configurations.

5. 5. The turbine expander of claim 4, wherein the first geometric configuration of the first nozzle is a DeLaval configuration having a first throat cross-sectional area, the second geometric configuration of the second nozzle is a DeLaval configuration having a second throat cross-sectional area, the third geometric configuration of the third nozzle is a DeLaval configuration having a third throat cross-sectional area, and the fourth geometric configuration is a DeLaval configuration having a fourth throat cross-sectional area, each of the first, second, third, and fourth throat cross-sectional areas being different.

6. The turbine expander of any preceding claim, wherein the first and second nozzle components are circumferentially spaced about the longitudinal axis.

7. 7. The turbine expander of claim 5 or 6, wherein the first, second, third and fourth nozzle components are circumferentially spaced about the longitudinal axis.

8. A turbine expander according to any preceding claim, wherein the first and second nozzle components are integral with the nozzle block.

9. The turbine expander according to any one of claims 1 to 8, wherein at least a portion of the nozzle block is disposed between the first nozzle and the turbine blade.

10. A waste heat recovery system for recovering waste heat from an internal combustion engine, comprising: The turbine expander according to any one of claims 1 to 9; a flow control device in fluid communication with the turbine expander for directing the working fluid to at least one of the first and second nozzles or for bypassing the turbine expander; and a controller in communication with the flow control device and adapted to control the flow control device to direct the working fluid to at least one of the first and second nozzles or to bypass the turbine expander.

11. The waste heat recovery system of claim 10 , further comprising at least one sensor adapted to detect at least one of a working fluid temperature and a working fluid pressure of the working fluid upstream of the turbine expander.

12. 12. The waste heat recovery system of claim 11, wherein the controller controls the flow control device to direct the working fluid to at least one of the first and second nozzles or to bypass the turbine expander based on at least one of the working fluid temperature and the working fluid pressure detected by the at least one sensor.

13. 1. A turbine expander for a waste heat recovery system for outputting power based on a working fluid, comprising: a turbine blade rotatable by the working fluid; and a shaft coupled to and rotatable by said turbine blades; and a nozzle assembly for directing the working fluid to the turbine blades to rotate the turbine blades, the nozzle assembly comprising: a nozzle block disposed about the shaft adjacent the turbine blades and defining a first bore; and a nozzle component removably coupled to the nozzle block to selectively position a plurality of different geometric configurations within the bore to accelerate the working fluid, the nozzle component defining a nozzle; At least a portion of the nozzle block is disposed between the nozzle and the turbine blades.

14. A waste heat recovery system for recovering waste heat from an internal combustion engine, comprising: A turbine expander for outputting power based on a working fluid, the turbine expander comprising: a turbine blade rotatable by the working fluid; and a shaft coupled to and rotatable by the turbine blades, the shaft extending along a longitudinal axis; and a nozzle assembly for directing the working fluid to the turbine blades to rotate the turbine blades, the nozzle assembly comprising: a nozzle block disposed about the shaft adjacent the turbine blades and defining a bore; and a nozzle component removably coupled to the nozzle block to selectively position a plurality of different geometric configurations within the bore to accelerate the working fluid, the nozzle component defining a nozzle; a flow control device in fluid communication with the turbine expander for directing the working fluid to the nozzle or to bypass the turbine expander; and a controller in communication with the flow control device and adapted to control the flow control device to direct the working fluid to the nozzle or to bypass the turbine expander.

15. The waste heat recovery system of claim 14 , wherein at least a portion of the nozzle block is disposed between the nozzle and the turbine blade.

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