Expansion machine with variable expansion ratio and control method thereof

Abstract

The invention relates to a variable-expansion-ratio expansion machine and a control method thereof. The expansion machine comprises a working cavity composed of a cylinder cover, a cylinder sleeve and a piston; the working cavity is located in the end area, close to the cylinder cover, of the cylinder sleeve. The cylinder sleeve is arranged in the cylinder body, and side grooves are formed in the two opposite sides of the cylinder sleeve correspondingly. The driving mechanism is arranged above the cylinder cover and is fixedly connected with the adjusting mechanism; the adjusting structures are arranged on the two opposite sides of the cylinder sleeve and are adjacent to the side grooves; an air inlet and an air outlet which are communicated with the side grooves are formed in the positions, on the two opposite sides of the cylinder sleeve, of the cylinder body respectively. An air inlet channel penetrating to the top of the piston is arranged in the piston; the air inlet, the air inlet channel, the working cavity and the air outlet jointly form an air inlet and outlet channel. The driving mechanism and the adjusting structure are used for adjusting the opening and closing time of the intake and exhaust passage so as to adjust the expansion ratio of the expander. According to the expansion machine with the variable expansion ratio, the expansion ratio can be adjusted in real time, the working condition adaptability and the expansion efficiency of the expansion machine are improved, and high performance of the expansion machine under different working conditions is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of waste heat recovery, and particularly to a variable expansion ratio expander and its control method. Background Art

[0002] With the increasing global energy shortage and stringent environmental protection requirements, improving energy utilization efficiency has become an important research direction in the field of thermal energy engineering. In vehicle power systems, although traditional internal combustion engines can release a large amount of energy during the combustion process, due to thermal efficiency limitations, approximately 60% of the fuel energy is discharged in the form of exhaust gas or coolant and is not effectively converted into mechanical output work. Therefore, waste heat recovery technology has received extensive attention.

[0003] As a medium and low temperature waste heat recovery technology, the Organic Rankine Cycle (ORC) has become the mainstream technical route for vehicle waste heat recovery due to its strong adaptability, relatively simple system structure, and diverse working fluids. Among them, the expander, as the core component of the ORC system, its structural form and operating parameters directly determine the energy recovery ability and dynamic response performance of the system.

[0004] Most expanders in traditional technologies adopt a fixed expansion ratio design, with fixed intake and exhaust passage structures and an unadjustable expansion ratio, suitable for operation under stable working conditions. However, in vehicle applications, the engine working conditions change frequently, and the exhaust temperature and pressure fluctuate greatly. Fixed expansion ratio expanders are difficult to adapt to different operating conditions, resulting in sub - optimal efficiency under different loads. Summary of the Invention

[0005] Based on this, it is necessary to provide a variable expansion ratio expander and its control method that can change the expansion ratio of the expander, improve the adaptability of the expander to working conditions, and enhance the performance and energy recovery efficiency of the expander under different working conditions for the above - mentioned technical problems.

[0006] In a first aspect, the present application provides a variable expansion ratio expander, which includes:

[0007] A working chamber, composed of a cylinder head, a cylinder liner, and a piston; the working chamber is located in the end region of the cylinder liner close to the cylinder head; the cylinder liner is arranged inside the cylinder block, and side grooves are respectively arranged on opposite sides of the cylinder liner;

[0008] A driving mechanism, arranged above the cylinder head and fixedly connected to the adjusting mechanism;

[0009] An adjusting structure, arranged on opposite sides of the cylinder liner and adjacent to the side grooves;

[0010] Among them, the cylinder block is provided with an air inlet and an exhaust port communicating with the side grooves on opposite sides of the cylinder liner; an air inlet passage penetrating to the top is provided inside the piston; the air inlet, the air inlet passage, the working chamber, and the exhaust port together form an intake and exhaust passage; the driving mechanism and the adjusting structure are used to adjust the opening and closing moments of the intake and exhaust passage to adjust the expansion ratio of the expander.

[0011] In one embodiment, first side grooves and second side grooves are respectively formed on opposite sides of the cylinder liner; the adjusting structure includes:

[0012] An air intake slider member, arranged adjacent to the first side groove; the air intake slider member includes an air intake upper slider and an air intake lower slider, and the air intake upper slider and the air intake lower slider form an air intake cavity;

[0013] An exhaust slider member, arranged adjacent to the second side groove; the exhaust slider member includes an exhaust upper slider and an exhaust lower slider, and the exhaust upper slider and the exhaust lower slider form an exhaust cavity.

[0014] In one embodiment, the intake and exhaust passage includes an intake passage and an exhaust passage; the first side groove communicates with the air inlet through the air intake cavity, and the air inlet, the air intake cavity, the first side groove, and the air inlet passage together form the intake passage; the second side groove communicates with the exhaust port through the exhaust cavity, and the working chamber, the second side groove, the exhaust cavity, and the exhaust port together form the exhaust passage.

[0015] In one embodiment, the air inlet passage is L-shaped; the first end of the air inlet passage is connected to the first side groove for communicating with the air intake cavity through the first side groove; the second end of the air inlet passage is connected to the working chamber for communicating the working chamber with the air intake cavity.

[0016] In one embodiment, both the air intake upper slider and the air intake lower slider are fixedly connected to the driving mechanism; the driving mechanism is used to drive the air intake upper slider and the air intake lower slider to move along the axial direction of the cylinder liner to control the opening and closing moments of the intake passage;

[0017] Both the exhaust upper slider and the exhaust lower slider are fixedly connected to the driving mechanism; the driving mechanism is used to drive the exhaust upper slider and the exhaust lower slider to move along the axial direction of the cylinder liner to control the opening and closing moments of the exhaust passage.

[0018] In one embodiment, the expander further includes:

[0019] A fixing ring, provided at the end region of the piston close to the working chamber, and the fixing ring is used to seal the gap between the piston and the cylinder liner.

[0020] In one embodiment, the expander further includes:

[0021] A cover, provided above the cylinder head and covering the driving mechanism for covering the driving mechanism.

[0022] In one embodiment, the expander further includes:

[0023] A crankcase, located below the piston, for mounting the crank connecting rod mechanism;

[0024] A crank connecting rod mechanism, connected to the piston, for converting the reciprocating linear motion of the piston into the rotational motion of the crankshaft, or realizing the reciprocating linear motion of the piston by utilizing the inertial rotation of the crankshaft.

[0025] Second, the present application also provides a control method for a variable expansion ratio expander, which is applied to any variable expansion ratio expander in the first aspect; the method includes:

[0026] Obtain the current operating parameters of the expander, and determine the target expansion ratio of the expander according to the current operating parameters;

[0027] Determine the target opening and closing moments of the intake passage and the target opening and closing moments of the exhaust passage according to the target expansion ratio;

[0028] Based on the target opening and closing moments of the intake passage and the target opening and closing moments of the exhaust passage, determine the target positions of the intake slider and the exhaust slider respectively;

[0029] Adjust the positions of the intake slider and the exhaust slider according to the target positions of the intake slider and the exhaust slider.

[0030] In one embodiment, the method further includes:

[0031] When the intake lower slider moves downward along the axial direction of the cylinder liner, and the exhaust upper slider moves downward along the axial direction of the cylinder liner, the closing moment of the intake passage is delayed and the opening moment of the exhaust passage is delayed.

[0032] The above variable expansion ratio expander and its control method, the expander includes: a working chamber, which is composed of a cylinder head, a cylinder liner and a piston; the working chamber is located in the end region of the cylinder liner close to the cylinder head; the cylinder liner is arranged inside the cylinder block, and side grooves are respectively arranged on the opposite sides of the cylinder liner; a driving mechanism, arranged above the cylinder head and fixedly connected to the adjusting mechanism; an adjusting structure, arranged on the opposite sides of the cylinder liner and adjacent to the side grooves; wherein, the cylinder block is respectively provided with an intake port and an exhaust port communicated with the side grooves on the opposite sides of the cylinder liner; an intake passage penetrating through to the top is arranged inside the piston; the intake port, the intake passage, the working chamber and the exhaust port together form an intake and exhaust passage; the driving mechanism and the adjusting structure are used to adjust the opening and closing moments of the intake and exhaust passage to adjust the expansion ratio of the expander. Using the present variable expansion ratio expander can change the expansion ratio of the expander, improve the working condition adaptability of the expander, and improve the energy utilization recovery rate. Description of the Drawings

[0033] To more clearly illustrate the technical solutions in the embodiments of the present application or in related technologies, the following will briefly introduce the accompanying drawings required for the description of the embodiments or related technologies. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0034] Figure 1 Schematic structural diagram of a variable expansion ratio expander in an embodiment;

[0035] Figure 2 Schematic diagram of the positions of the cylinder liner and the adjusting structure in the cylinder body in an embodiment;

[0036] Figure 3 Schematic flow chart of the control method of a variable expansion ratio expander in an embodiment.

[0037] 100, working chamber; 200, driving mechanism; 300, adjusting structure; 400, cylinder block; 500, cover; 600, crankcase; 700, crank connecting rod mechanism; 102, cylinder head; 104, cylinder liner; 106, piston; 302, intake upper slider; 304, intake lower slider; 306, exhaust upper slider; 308, exhaust lower slider; 401, intake port; 402, exhaust port; 1062, intake passage; 1064, fixing ring. Detailed implementation manners

[0038] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will make a detailed description of the specific implementation manners of the present application in conjunction with the accompanying drawings. Many specific details are set forth in the following description to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein. Those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0039] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0041] In this application, unless otherwise clearly specified and defined, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] In this application, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or diagonally above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or diagonally below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0043] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0044] Traditional expanders adopt a fixed expansion ratio design, with fixed intake and exhaust passage structures and an unadjustable expansion ratio, which are suitable for operation under stable conditions. However, in vehicle applications, the engine operating conditions change frequently, and the exhaust temperature and pressure fluctuate greatly. Traditional fixed-expansion expanders cannot meet the requirements of different operating conditions. Specifically, under different operating conditions (such as engine load, speed, and temperature changes), the state of the working medium entering the expander will change. A fixed expansion ratio may perform well under a certain operating condition, but under other operating conditions, there may be problems of insufficient expansion (wasting available energy) and over-expansion (too low outlet pressure and reduced efficiency), resulting in a low conversion and utilization rate of the thermal energy of traditional fixed-expansion expanders, and the efficiency under different operating conditions cannot be optimized. This application proposes a variable expansion ratio expander that can solve the problems of unadjustable expansion ratio and low efficiency of the expander. Specifically, this application dynamically controls the opening and closing moments of the intake and exhaust passages through an adjustment structure to achieve real-time adjustment of the expansion ratio of the expander, thereby maximizing the conversion of the thermal energy of the working medium into mechanical energy, reducing exhaust losses, and improving the expansion efficiency; at the same time, it can improve the operating condition adaptability of the expander, thus ensuring high performance of the expander under different operating conditions.

[0045] In a first aspect, please refer to Figure 1 and Figure 2 , Figure 1 which shows a schematic structural diagram of a variable expansion ratio expander in an embodiment of this application, Figure 2 and which shows a schematic diagram of the positions of the cylinder liner 104 and the adjustment structure 300 in the cylinder block 400 in an embodiment of this application; the expander includes: a working chamber 100, which is composed of a cylinder head 102, a cylinder liner 104, and a piston 106; the working chamber 100 is located in the end region of the cylinder liner 104 close to the cylinder head 102; the cylinder liner 104 is disposed inside the cylinder block 400, and side grooves are respectively provided on opposite sides of the cylinder liner 104; a driving mechanism 200, which is disposed above the cylinder head 102 and is fixedly connected to the adjustment mechanism; an adjustment structure 300, which is disposed on opposite sides of the cylinder liner 104 and is arranged adjacent to the side grooves; wherein, the cylinder block 400 is respectively provided with an intake port 401 and an exhaust port 402 communicating with the side grooves on opposite sides of the cylinder liner 104; an intake passage 1062 penetrating through to the top is provided inside the piston 106; the intake port 401, the intake passage 1062, the working chamber 100, and the exhaust port 402 together constitute the intake and exhaust passage; the driving mechanism 200 and the adjustment structure 300 are used to adjust the opening and closing moments of the intake and exhaust passage to adjust the expansion ratio of the expander.

[0046] Exemplarily, the working chamber 100 is a sealed space jointly formed by the cylinder head 102, the cylinder liner 104, and the piston 106. The working chamber 100 is located at one end of the cylinder liner 104 close to the cylinder head 102, and is mainly used for the intake, expansion work, and discharge of high-pressure working medium. The cylinder liner 104, as a structural component that limits the movement space of the piston 106, is fixedly installed inside the cylinder block 400. A long strip-shaped side groove is provided on each of its opposite sides, and this side groove is used to cooperate with the adjustment structure 300 to control the opening and closing of the intake port 401 and the exhaust port 402.

[0047] The cylinder block 400 is respectively provided with an intake port 401 and an exhaust port 402 corresponding to the opposite sides of the cylinder liner 104, and is communicated with the side grooves of the above-mentioned cylinder liner 104, thereby forming an air flow channel. Further, in order to introduce the working medium from the outside of the cylinder block 400 into the working chamber 100, an intake passage 1062 that penetrates to the top is provided inside the piston 106. The first end of the intake passage 1062 can be communicated with the intake port 401 through the side groove, and the second end of the intake passage 1062 leads to the working chamber 100, so that the working medium can enter through the path of intake port 401 → side groove → intake passage 1062 → working chamber 100.

[0048] The adjustment structures 300 are respectively arranged on both sides of the cylinder liner 104 and close to the side grooves. The driving mechanism 200 cooperates with the adjustment structure 300 to adjust the opening and closing moments of the intake and exhaust passages. Specifically, the driving mechanism 200 is used to drive the adjustment structure 300 to move in the axial direction of the cylinder liner 104 to adjust the opening and closing moments of the intake and exhaust passages, and further adjust the expansion ratio of the expander. Among them, the driving mechanism 200 is installed above the cylinder head 102 and can be a stepper motor, a servo motor or other forms of driving units. Its output end is fixedly connected to the adjustment structure 300 and is responsible for providing precise up and down movement power.

[0049] Optionally, one end of the piston 106 away from the intake passage 1062 is connected to the crank connecting rod mechanism 700. The adjusting structure 300 includes an intake upper slider 302, an intake lower slider 304, an exhaust upper slider 306, and an exhaust lower slider 308. The working mode of this variable expansion ratio expander is as follows: The intake port 401 of the cylinder block 400 is introduced with high-pressure working medium. When the piston 106 moves downward from the top dead center to the first target position in the cylinder liner 104, the intake passage 1062 can be communicated with the intake port 401 to form an intake passage. Herein, the first target position refers to the position where the intake passage 1062 of the cylinder liner 104 can be communicated with the intake cavity formed by the intake upper slider 302 and the intake lower slider 304. At this time, the high-pressure working medium enters the working chamber 100 through the intake passage. Under the push of this high-pressure working medium, the piston 106 moves downward and pushes the crank connecting rod mechanism 700 to rotate and output shaft work. When the piston 106 moves downward near the bottom dead center, the upper edge of the piston 106 (i.e., the working chamber 100) can be communicated with the exhaust cavity formed by the exhaust upper slider 306 and the exhaust lower slider 308, so that the exhaust passage is opened. And the crank connecting rod mechanism 700 continues to rotate under the action of inertia to push the piston 106 upward. The expanded working medium exhaust gas in the working chamber 100 is discharged through the exhaust port 402 until the upper edge of the piston 106 blocks the exhaust port 402 and the exhaust process ends. When the piston 106 moves upward near the top dead center in the cylinder liner 104 and the intake port 401 is communicated with the intake passage 1062, the next cycle is started, thereby realizing a reciprocating motion type expansion work process similar to a two-stroke engine. Herein, the high-pressure working medium refers to the working medium in a high-pressure state, that is, the medium that has not undergone expansion work and still stores relatively high energy. The working medium exhaust gas refers to the working medium that has undergone the expansion process and completed the work.

[0050] During the working process of the above variable expansion ratio expander, the driving mechanism 200 is respectively connected to the intake upper slider 302, the intake lower slider 304, the exhaust upper slider 306, and the exhaust lower slider 308 of the adjusting structure 300. The driving mechanism 200 is used to control the intake upper slider 302, the intake lower slider 304, the exhaust upper slider 306, and the exhaust lower slider 308 to move up and down within a limited length to adjust the opening and closing moments of the intake and exhaust passages. Exemplarily, please refer to again Figure 1, when the driving mechanism 200 controls the downward movement of the intake lower slider 304, the closing moment of the intake passage is delayed, increasing the intake air volume; when the driving mechanism 200 controls the downward movement of the exhaust upper slider 306, the opening moment of the exhaust passage is delayed, increasing the expansion ratio of the expander and making the expansion process more sufficient. Therefore, according to actual requirements, the driving mechanism 200 can be used to adjust the real-time positions of the intake upper slider 302, intake lower slider 304, exhaust upper slider 306, and exhaust lower slider 308 to change the opening and closing moments of the intake and exhaust of the expander (i.e., the opening and closing moments of the intake passage and exhaust passage) and the intake air volume, realizing the adjustability of the expansion ratio of the expander, enhancing the working condition adaptability and transient response of the organic Rankine cycle system, and improving the system energy recovery efficiency.

[0051] In this embodiment, by adjusting the positions of the intake upper slider 302 and intake lower slider 304 in the adjustment structure 300 through the driving mechanism 200, the conduction time between the intake port 401 and the intake passage 1062 can be regulated, and then the intake air volume entering the working chamber 100 can be adjusted to regulate the output power; by adjusting the positions of the exhaust upper slider 306 and exhaust lower slider 308 in the adjustment structure 300 through the driving mechanism 200, the conduction time (i.e., the exhaust time) between the working chamber 100 and the exhaust port 402 can be regulated, and then the expansion ratio of the expander can be adjusted to meet different working condition requirements. Therefore, the variable expansion ratio expander of this embodiment can improve the working condition adaptability of the expander and ensure high performance and high energy recovery efficiency of the expander under different working conditions.

[0052] In an exemplary embodiment, first side grooves and second side grooves are respectively formed on opposite sides of the cylinder liner 104; the adjustment structure 300 includes: an intake slider member disposed adjacent to the first side groove; the intake slider member includes an intake upper slider 302 and an intake lower slider 304, and the intake upper slider 302 and the intake lower slider 304 form an intake cavity; an exhaust slider member disposed adjacent to the second side groove; the exhaust slider member includes an exhaust upper slider 306 and an exhaust lower slider 308, and the exhaust upper slider 306 and the exhaust lower slider 308 form an exhaust cavity.

[0053] Exemplarily, a first side groove is formed on the first side of the cylinder liner 104, and a second side groove is formed on the second side of the cylinder liner 104. The first side of the cylinder liner 104 is the side close to the intake passage 1062 inside the piston 106. The first side groove and the second side groove serve as the internal openings of the intake passage and the exhaust passage. The first side groove and the second side groove can respectively serve as the channel openings for the intake process and the exhaust process. Specifically, the first side groove can communicate the intake port 401 and the intake passage 1062 inside the piston 106, enabling high-pressure working medium to enter the working chamber 100; the second side groove can communicate the working chamber 100 and the exhaust port 402, enabling the expanded low-pressure exhausted gas to be discharged from the working chamber 100 to the exhaust port 402.

[0054] The adjusting structure 300 includes an intake slider and an exhaust slider. Among them, the intake slider is disposed near the first side groove and is used to control the opening time and closing time of the intake passage; the exhaust slider is disposed near the second side groove and is used to control the opening time and closing time of the exhaust passage. Optionally, the intake slider includes an upper intake slider 302 and a lower intake slider 304. The upper intake slider 302 and the lower intake slider 304 jointly define a gap area with an adjustable height at the first side groove, thereby forming an intake cavity with a variable volume. The upper and lower boundaries of the intake cavity are jointly determined by the positions of the upper intake slider 302 and the lower intake slider 304. Similarly, the exhaust slider includes an upper exhaust slider 306 and a lower exhaust slider 308. The upper exhaust slider 306 and the lower exhaust slider 308 jointly define a variable-volume exhaust cavity at the second side groove. The upper and lower boundaries of the exhaust cavity are jointly determined by the positions of the upper exhaust slider 306 and the lower exhaust slider 308 to control the opening and closing times of the exhaust passage.

[0055] In this embodiment, a first side groove and a second side groove are respectively provided on opposite sides of the cylinder liner 104, and an intake slider and an exhaust slider are respectively arranged at positions adjacent to the first side groove and the second side groove, so that the opening and closing times of the intake passage and the exhaust passage and the intake air volume can be accurately controlled. Among them, the upper intake slider 302, the lower intake slider 304, the upper exhaust slider 306, and the lower exhaust slider 308 respectively enclose an intake cavity and an exhaust cavity with variable volumes, so that the opening and closing times of the intake passage and the exhaust passage can be flexibly adjusted according to the actual working conditions, and the intake air volume entering the working chamber 100 can be flexibly adjusted.

[0056] In an exemplary embodiment, the intake passage 1062 is L-shaped; the first end of the intake passage 1062 is connected to the first side groove and is used to communicate with the intake cavity through the first side groove and communicate with the intake port 401 through the intake cavity; the second end of the intake passage 1062 is connected to the working chamber 100 and is used to communicate the working chamber 100 with the intake cavity.

[0057] Optionally, to smoothly introduce high-pressure working fluid from outside the cylinder block 400 into the working chamber 100, the intake passage 1062 is set to an L-shaped structure. The intake passage 1062 is disposed inside the piston 106 and extends along the axis of the piston 106 and its perpendicular direction to form a fold angle. The first end of the intake passage 1062 faces the side wall of the cylinder liner 104 and is connected to the first side groove. When the piston 106 is moving, the first end of the intake passage 1062 can communicate with the intake cavity disposed in the first side groove at a specific position, so that the high-pressure working fluid from outside the cylinder block 400 enters the intake cavity through the intake port 401, and then is introduced into the intake passage 1062 through the first end of the intake passage 1062. The second end of the intake passage 1062 penetrates through to the top of the piston 106 and communicates with the working chamber 100. When the high-pressure working fluid flows to the second end of the intake passage 1062 through the intake passage 1062, it can enter the working chamber 100 above the piston 106, and then push the piston 106 to do work. At the end of the expansion process of the expander, when the piston 106 continues to move to the exhaust stage, the second end of the intake passage 1062 can also be temporarily communicated with the exhaust cavity through the working chamber 100, so that the expanded working fluid exhaust gas in the working chamber 100 can be discharged through the exhaust passage.

[0058] In this embodiment, the intake passage 1062 is set to an L-shaped structure, and the intake cavity and the working chamber 100 are respectively connected to both ends of the intake passage 1062, which can optimize the air flow path, improve the smoothness of the working fluid transportation and the charging efficiency, and can also realize the compactness of the structure layout, which is beneficial to improving the airtightness and the overall strength.

[0059] In the previous exemplary embodiment, the intake and exhaust passages include an intake passage and an exhaust passage; the first side groove is communicated with the intake port 401 through the intake cavity, and the intake port 401, the intake cavity, the first side groove and the intake passage 1062 together constitute the intake passage; the second side groove is communicated with the exhaust port 402 through the exhaust cavity, and the working chamber 100, the second side groove, the exhaust cavity and the exhaust port 402 together constitute the exhaust passage.

[0060] Based on the above embodiments, when the intake cavity is in communication with the intake port 401, as the piston 106 moves, when the first end of the intake passage 1062 can communicate with the intake cavity arranged at the first side groove at a specific position, the high-pressure working fluid can enter the intake cavity and the intake passage 1062 in sequence from the intake port 401, and then enter the working chamber 100, realizing the supply of gas to the working chamber 100. Thus, the intake port 401, the intake cavity, the first side groove, and the intake passage 1062 are sequentially connected to form a complete intake passage, enabling the high-pressure working fluid to flow into the working chamber 100 from the intake port 401 through the above path. Correspondingly, the second side groove can communicate with the exhaust port 402 through the exhaust cavity, and the working chamber 100 can communicate with the exhaust cavity through the second side groove. Exemplarily, when the high-pressure working fluid flows into the working chamber 100 from the intake port 401 through the intake passage, the high-pressure working fluid pushes the piston 106 to do work. At the end of the expansion process of the expander, when the piston 106 continues to move to the exhaust stage, the working chamber 100 communicates with the exhaust cavity, and then with the exhaust port 402, so that the exhausted working fluid in the working chamber 100 can be discharged through the exhaust cavity and the exhaust port 402. Thus, the working chamber 100, the second side groove, the exhaust cavity, and the exhaust port 402 form an exhaust passage, realizing the discharge path of the exhausted working fluid from the working chamber 100 to the exhaust port 402.

[0061] In this embodiment, dividing the intake passage and the exhaust passage into structurally independent intake and exhaust passages can achieve the physical separation of the intake and exhaust paths, and also enables the intake and exhaust processes to be precisely controlled by respective independent slider members. Among them, the intake passage is composed of the intake port 401, the intake cavity, the first side groove, and the intake passage 1062, which can realize the process of the high-pressure working fluid entering the working chamber 100 from the outside; the exhaust passage is composed of the working chamber 100, the second side groove, the exhaust cavity, and the exhaust port 402, ensuring the smooth discharge of the exhausted working fluid after doing work.

[0062] In an exemplary embodiment, both the intake upper slider 302 and the intake lower slider 304 are fixedly connected to the drive mechanism 200; the drive mechanism 200 is used to drive the intake upper slider 302 and the intake lower slider 304 to move along the axial direction of the cylinder liner 104 to control the opening and closing moments of the intake passage; both the exhaust upper slider 306 and the exhaust lower slider 308 are fixedly connected to the drive mechanism 200; the drive mechanism 200 is used to drive the exhaust upper slider 306 and the exhaust lower slider 308 to move along the axial direction of the cylinder liner 104 to control the opening and closing moments of the exhaust passage.

[0063] The intake upper slider 302 and the intake lower slider 304 are both fixedly connected to the drive mechanism 200 provided on the cylinder head 102, and the exhaust upper slider 306 and the exhaust lower slider 308 are also fixedly connected to the drive mechanism 200, enabling the drive mechanism 200 to drive the slider members to move independently. The drive mechanism 200 can adopt a drive mechanism 200 in any structural form such as a stepping motor, a transmission gear, etc. and is connected to the adjustment mechanism (i.e., the intake upper slider 302, the intake lower slider 304, the exhaust upper slider 306, and the exhaust lower slider 308) in any manner.

[0064] Optionally, during the intake process of the high-pressure working fluid, the drive mechanism 200 can drive the intake upper slider 302 and the intake lower slider 304 to change the relative positions of the intake upper slider 302 and the intake lower slider 304 in the first side groove area, thereby dynamically adjusting the position and volume of the intake cavity; among them, the adjustment of the position of the intake cavity can affect the opening and closing moments of the intake passage, and the adjustment of the volume of the intake cavity can affect the intake amount of the working fluid entering the working chamber 100. During the exhaust process of the high-pressure working fluid, the drive mechanism 200 also drives the relative positions of the exhaust upper slider 306 and the exhaust lower slider 308 in the second side groove area to move axially, thereby dynamically adjusting the position of the exhaust cavity, and further realizing the dynamic regulation of the opening and closing moments of the exhaust passage.

[0065] In this embodiment, through the intake cavity and the exhaust cavity with variable volume and variable position, the opening and closing moments of the intake passage and the exhaust passage can be flexibly adjusted according to the actual working conditions, and the regulation of the intake amount can be realized, thereby dynamically adjusting the expansion ratio of the expander and improving the adaptability and energy-saving effect of the expander.

[0066] In an exemplary embodiment, the expander further includes: a fixing ring 1064, which is provided at the end region of the piston 106 close to the working chamber 100, and the fixing ring 1064 is used to seal the gap between the piston 106 and the cylinder liner 104.

[0067] The piston 106 is arranged inside the cylinder liner 104, and a fixing ring 1064 is provided on the top side circular surface of the piston 106, and the fixing ring 1064 is used to prevent the working fluid in the cylinder from leaking into the crankcase 600 located below the cylinder liner 104. Optionally, the fixing ring 1064 is provided in the outer peripheral surface area of the end of the piston 106 close to the working chamber 100, near the contact position between the top of the piston 106 and the cylinder liner 104. The fixing ring 1064 can be sleeved on the outside of the piston 106 and is arranged closely against the inner wall of the cylinder liner 104 in the assembled state, so as to fill the annular gap between the piston 106 and the cylinder liner 104, play a role in sealing and leakage prevention, prevent the working fluid from leaking outside the piston 106 during the expansion process, and thus ensure the tightness and energy conversion efficiency of the expansion process.

[0068] In this embodiment, a fixed ring 1064 is provided above the piston 106, which can effectively prevent the leakage of the working medium, reduce the wear of the piston 106 caused by the erosion of high-pressure gas during reciprocating motion, and improve the sealing life and structural reliability.

[0069] In an exemplary embodiment, the expander further includes: a cover 500, disposed above the cylinder head 102 and covering the driving mechanism 200 for wrapping the driving mechanism 200.

[0070] The cover 500 is installed above the cylinder head 102 and covers the peripheral area of the driving mechanism 200 to form a wrapping structure for the driving mechanism 200, so that the driving mechanism 200 is in a closed or semi-closed space, which can prevent external dust, water vapor or other impurities from entering the interior of the driving mechanism 200, thereby avoiding mechanism jamming, corrosion or performance degradation caused by foreign object intrusion; on the other hand, the cover 500 can also play a safety protection role to prevent personnel from accidentally touching high-speed moving or high-temperature driving components.

[0071] In an exemplary embodiment, the expander further includes: a crankcase 600, located below the piston 106, for installing a crank connecting rod mechanism 700; a crank connecting rod mechanism 700, connected to the piston 106, for converting the reciprocating linear motion of the piston 106 into the rotational motion of the crankshaft, or using the inertia rotation of the crankshaft to realize the reciprocating linear motion of the piston 106.

[0072] The piston 106 reciprocates in the cylinder liner 104 under the push of high-pressure working medium. The output shaft work component follows the design of the crank connecting rod flywheel of the reciprocating piston 106 type internal combustion engine and uses inertia to complete the reciprocating cycle. One rotation of the crank can complete one intake, expansion, and exhaust cycle, which is a two-stroke-like expander. Since the required optimal actual expansion ratio is different under different working conditions, the above variable expansion ratio expander can achieve efficient power output with adaptive changes in the expansion ratio under different working conditions.

[0073] Optionally, the crankcase 600 is disposed in the lower area of the piston 106 and is used to accommodate and install the crank connecting rod mechanism 700. One end of the crank connecting rod mechanism 700 is connected to the lower part of the piston 106, and the other end is connected to the crankshaft located in the crankcase 600. The crank connecting rod mechanism 700 is a transmission structure inside the expander, and its function is to realize the conversion of energy forms; specifically, when the expanding working medium pushes the piston 106 to reciprocate linearly in the cylinder liner 104, the crank connecting rod mechanism 700 can convert this linear motion into the rotational motion of the crankshaft, and then output rotational mechanical energy; conversely, the inertial rotation of the crankshaft can also drive the piston 106 to generate reciprocating motion through the crank connecting rod mechanism 700 to realize the self-circulation start or continuous operation of the expander.

[0074] In the second aspect, as Figure 3As shown, the present application provides a control method for a variable expansion ratio expander, which is applied to the variable expansion ratio expander in the first aspect; the method includes step 3002 to step 3008. Among them:

[0075] Step 3002, obtain the current operating parameters of the expander, and determine the target expansion ratio of the expander according to the current operating parameters.

[0076] Step 3004, determine the target opening and closing time of the intake passage and the target opening and closing time of the exhaust passage according to the target expansion ratio.

[0077] Step 3006, based on the target opening and closing time of the intake passage and the target opening and closing time of the exhaust passage, respectively determine the target positions of the intake slider and the exhaust slider.

[0078] Step 3008, adjust the positions of the intake slider and the exhaust slider according to the target positions of the intake slider and the exhaust slider.

[0079] This method is applicable to any variable expansion ratio expander in the first aspect, aiming to achieve dynamic adjustment of the expansion ratio according to the operating state to improve the expansion efficiency and system adaptability. Exemplarily, obtain the current operating parameters of the expander, and the operating parameters may include data related to the working conditions such as rotational speed, load, intake pressure, exhaust pressure, and medium temperature; the system calculates the current optimal target expansion ratio based on these operating parameters, and this target expansion ratio is used to improve the energy utilization efficiency under the current working conditions. Subsequently, according to the determined target expansion ratio, further calculate the target opening and closing times required for the intake passage and the exhaust passage. The opening and closing time of the intake passage determines the timing and duration of the high-pressure working medium entering the working chamber 100, while the opening and closing time of the exhaust passage determines the termination point of the expansion process. These two times together determine the effective expansion ratio range. After clarifying the above opening and closing times, based on the time-position mapping relationship, calculate the target positions of the intake slider and the exhaust slider in the axial direction of the cylinder liner 104 respectively, and then form an adjustment instruction. Finally, according to the target positions of the intake slider and the exhaust slider in the axial direction of the cylinder liner 104, accurately adjust the axial positions of the intake slider and the exhaust slider respectively to achieve dynamic control of the opening and closing times of the intake passage and the exhaust passage, so that the actual expansion ratio of the expander is consistent with the target expansion ratio. This method can adjust the expansion ratio in real time according to the change of working conditions, effectively improve the operating efficiency, energy saving performance and system response ability of the expander under variable working conditions, and has good engineering practicability and popularization value.

[0080] In an exemplary embodiment, the method further includes: when the intake lower slider 304 moves downward along the axial direction of the cylinder liner 104 and the exhaust upper slider 306 moves downward along the axial direction of the cylinder liner 104, the closing time of the intake passage is delayed and the opening time of the exhaust passage is delayed.

[0081] By adjusting the positions of the intake slider and the exhaust slider in the axial direction of the cylinder liner 104, the opening and closing times of the intake passage and the exhaust passage are dynamically adjusted to achieve fine control of the expansion ratio. Exemplarily, during the intake process, when the upper intake slider 302 is stationary and the lower intake slider 304 moves downward along the axial direction of the cylinder liner 104 (i.e., slides away from the working chamber 100), the lower boundary position of the intake cavity moves downward accordingly, enabling the high-pressure working fluid to continuously enter the intake passage 1062 for a longer time and ultimately enter the working chamber 100, thereby delaying the closing time of the intake passage and extending the intake duration. During the exhaust process, when the lower exhaust slider 308 is stationary and the upper exhaust slider 306 moves downward along the axial direction of the cylinder liner 104 (i.e., slides towards the bottom of the cylinder block 400), the upper boundary position of the exhaust cavity also moves downward, thus delaying the communication time between the exhaust cavity and the working chamber 100, that is, delaying the opening time of the exhaust passage, so that the expansion process can continue in the working chamber 100 for a longer time.

[0082] In this embodiment, by synchronously delaying the closing time of the intake passage and the opening time of the exhaust passage, the expansion time of the high-pressure working fluid in the working chamber 100 can be effectively extended, thereby increasing the expansion ratio and enabling more energy to be released during the expansion process.

[0083] It should be understood that although the steps in the flowcharts involved in the above embodiments are sequentially shown according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same moment, but can be executed at different moments. The execution order of these steps or stages is not necessarily sequential either, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0084] In one embodiment, a computer device is provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, the steps in the above method embodiments are implemented.

[0085] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0086] In one embodiment, a computer program product is provided, including a computer program which, when executed by a processor, implements the steps in the above method embodiments.

[0087] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0088] Those of ordinary skill in the art can understand that all or part of the processes in the above method embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above method embodiments. Among them, any reference to a memory, database, or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in this application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., and are not limited thereto. The processors involved in the embodiments provided in this application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., and are not limited thereto.

[0089] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0090] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation to the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A variable expansion ratio expander, characterized in that, The expander includes: A working chamber, which is composed of a cylinder head, a cylinder liner and a piston; the working chamber is located in the end region of the cylinder liner close to the cylinder head; the cylinder liner is arranged inside the cylinder block, and side grooves are respectively arranged on the opposite sides of the cylinder liner; A driving mechanism, which is arranged above the cylinder head and fixedly connected to the adjusting mechanism; An adjusting structure, which is arranged on the opposite sides of the cylinder liner and is arranged adjacent to the side grooves; Wherein, the cylinder block is respectively provided with an air inlet and an air outlet communicated with the side grooves on the opposite sides of the cylinder liner; an air inlet passage penetrating to the top of the piston is arranged inside the piston; the air inlet, the air inlet passage, the working chamber and the air outlet jointly form an air intake and exhaust passage; the driving mechanism and the adjusting structure are used to adjust the opening and closing moments of the air intake and exhaust passage so as to adjust the expansion ratio of the expander.

2. The expander according to claim 1, wherein, First side grooves and second side grooves are respectively formed on the opposite sides of the cylinder liner; the adjusting structure includes: An air intake slider member, which is arranged adjacent to the first side groove; the air intake slider member includes an air intake upper slider and an air intake lower slider, and the air intake upper slider and the air intake lower slider form an air intake cavity; An exhaust slider member, which is arranged adjacent to the second side groove; the exhaust slider member includes an exhaust upper slider and an exhaust lower slider, and the exhaust upper slider and the exhaust lower slider form an exhaust cavity.

3. The expander according to claim 2, characterized in that The air intake and exhaust passage includes an air intake passage and an exhaust passage; the first side groove is communicated with the air inlet through the air intake cavity, and the air inlet, the air intake cavity, the first side groove and the air inlet passage jointly form the air intake passage; the second side groove is communicated with the air outlet through the exhaust cavity, and the working chamber, the second side groove, the exhaust cavity and the air outlet jointly form the exhaust passage.

4. The expander according to claim 3, characterized in that, The air inlet passage is L-shaped; the first end of the air inlet passage is connected to the first side groove for communicating with the air intake cavity through the first side groove; the second end of the air inlet passage is connected to the working chamber for communicating the working chamber with the air intake cavity.

5. The expander according to claim 3, characterized in that, Both the air intake upper slider and the air intake lower slider are fixedly connected to the driving mechanism; the driving mechanism is used to drive the air intake upper slider and the air intake lower slider to move along the axial direction of the cylinder liner so as to control the opening and closing moments of the air intake passage; Both the exhaust upper slider and the exhaust lower slider are fixedly connected to the driving mechanism; the driving mechanism is used to drive the exhaust upper slider and the exhaust lower slider to move along the axial direction of the cylinder liner so as to control the opening and closing moments of the exhaust passage.

6. The expander according to claim 1, characterized in that, The expander further includes: A fixing ring, which is arranged in the end region of the piston close to the working chamber, and the fixing ring is used to seal the gap between the piston and the cylinder liner.

7. The expander according to claim 1, wherein The expander further includes: A cover, which is arranged above the cylinder head and covers the driving mechanism for covering the driving mechanism.

8. The expander according to claim 1, wherein The expander further includes: A crankcase, which is located below the piston and is used to install a crank connecting rod mechanism; A crank connecting rod mechanism, which is connected to the piston and is used to convert the reciprocating linear motion of the piston into the rotational motion of the crankshaft, or use the inertial rotation of the crankshaft to realize the reciprocating linear motion of the piston.

9. A control method for a variable expansion ratio expander, characterized in that Applied to the variable expansion ratio expander according to any one of claims 1 to 8; the method includes: Obtain the current operating parameters of the expander, and determine the target expansion ratio of the expander according to the current operating parameters; Determine the target opening and closing moments of the intake passage and the target opening and closing moments of the exhaust passage according to the target expansion ratio; Based on the target opening and closing moments of the intake passage and the exhaust passage, respectively determine the target positions of the intake slider and the exhaust slider; Adjust the positions of the intake slider and the exhaust slider according to the target positions of the intake slider and the exhaust slider.

10. The method according to claim 9, characterized in that, The method further includes: When the intake lower slider moves downward along the axial direction of the cylinder liner and the exhaust upper slider moves downward along the axial direction of the cylinder liner, the closing moment of the intake passage is delayed and the opening moment of the exhaust passage is delayed.

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