Split free piston Stirling engine with common cavity and opposed

Abstract

The present invention provides a split free piston Stirling engine with a common cavity, including at least one group of hot cylinders and at least one group of cold cylinders, at least one group of hot cylinders is provided with a plurality of valve pistons arranged in pairs; at least one group of cold cylinders is provided with a plurality of power pistons arranged in pairs; a single valve piston or multiple groups of valve pistons are provided with a hot cavity, and the valve piston is provided with a first back pressure cavity on the side away from the hot cavity; a single power piston or multiple groups of power pistons are provided with a first cold cavity, and the side of the power piston away from the first cold cavity is a second back pressure cavity connected to the first back pressure cavity. In the above manner, the present invention reduces the vibration intensity of the engine operation, and can increase the operating frequency of the engine, so that the engine can achieve higher output under a more compact structure.

Description

Technical Field

[0001] The invention relates to the technical field of engines, and in particular to a split free-piston Stirling engine with opposing common cavities. Background Art

[0002] With the continuous growth of population and the improvement of people's living standards, the demand for energy is increasing, and fossil energy is becoming increasingly depleted; at the same time, the use of fossil energy has also led to problems such as global warming and climate change. The above contradictions have prompted people to explore new alternative energy sources, which requires more efficient ways of energy utilization. As an external combustion engine, the Stirling engine can convert any form of heat source into mechanical energy. In addition, the Stirling engine works based on the principle of closed cycle, has the advantages of low noise and no influence of air pressure, and the theoretical efficiency of the Stirling cycle is equal to the Carnot efficiency.

[0003] According to whether there is a transmission mechanism, Stirling engines can be divided into two types: kinematic and dynamic. As the most important structural type of dynamic Stirling engines, the free piston Stirling engine eliminates the moving parts used to connect the two pistons in the traditional kinematic Stirling engine, making the two pistons move independently. The pistons are dynamically coupled by gas pressure, and have the advantages of maintenance-free, self-starting and long life. Therefore, it has broad application prospects in deep space probe isotope power sources, large space nuclear power plants, ground solar power generation, industrial waste heat recovery, and household cogeneration.

[0004] The free piston Stirling engine is a vibration system, which is mainly composed of the power piston vibration system, the valve piston vibration system and the whole machine vibration system. The vibration of the power piston vibration system and the valve piston vibration system will cause the vibration of the whole engine. The vibration of the engine system will not only affect the performance and service life of the whole engine, but also reduce the reliability of the engine operation. A simple vibration reduction measure is to set two independent free piston Stirling generators opposite to each other. This setting can theoretically achieve the purpose of reducing vibration, but the premise is that the thermodynamic parameters of the two generators are completely consistent. If they are inconsistent, complex mutual coupling and influence will occur, and the vibration reduction effect will be reduced. Summary of the invention

[0005] The embodiment of the present invention provides a split free-piston Stirling engine with a common cavity and opposed to each other, so as to solve the technical problem that the vibration of the generator is greatly affected in the prior art.

[0006] The embodiment of the present invention provides a split free piston Stirling engine with a common cavity and opposed to each other, comprising: at least one group of hot cylinders, in which a plurality of valve pistons are arranged opposite to each other;

[0007] At least one group of cold cylinders, each of which is provided with a plurality of power pistons disposed opposite to each other;

[0008] A plurality of groups of the distribution pistons enclose a hot cavity, and a first back pressure cavity is provided on a side of the distribution piston away from the hot cavity; a plurality of groups of the power pistons enclose a first cold cavity, and a side of the power piston away from the first cold cavity is a second back pressure cavity connected to the first back pressure cavity.

[0009] According to an embodiment of the present invention, in a split free piston Stirling engine with a common cavity and opposed to each other, a partition plate and a gas distribution piston leaf spring are provided at one end of the gas distribution piston away from the other gas distribution piston arranged opposite to each other;

[0010] The partition is connected to the hot cylinder, a gas distribution piston rod is provided on the gas distribution piston, and the gas distribution piston leaf spring is connected to the gas distribution piston rod and the hot cylinder.

[0011] According to an embodiment of the present invention, in a split free piston Stirling engine with a common cavity and opposite to each other, a power piston leaf spring is provided at one end of the power piston away from the other power piston arranged opposite to each other;

[0012] The power piston is provided with a power piston rod, and the power piston leaf spring is connected with the power piston rod and the cold cylinder.

[0013] According to a split free piston Stirling engine with common cavities opposed to each other according to an embodiment of the present invention, a second cold cavity is provided between the valve piston and the partition plate;

[0014] A connecting pipe is provided between the hot cylinder and the cold cylinder, one end of the connecting pipe is connected to the second cold chamber, and the other end of the connecting pipe is connected to the first cold chamber.

[0015] According to a split free-piston Stirling engine with a common cavity opposed to each other according to one embodiment of the present invention, a heater is further provided on the outside of the hot cylinder, one end of the heater is communicated with the hot cavity, the other end of the heater is connected to a regenerator and a cooler, one end of the cooler is connected to the regenerator, and the other end is communicated with the second cold cavity.

[0016] According to a split free-piston Stirling engine with opposing common cavities according to one embodiment of the present invention, pressure-stabilizing pipes are provided outside the hot cylinder and the cold cylinder, and the pressure-stabilizing pipes are respectively connected to the first back-pressure chamber and the second back-pressure chamber, so that all of the first back-pressure chamber and the second back-pressure chamber are in a connected state.

[0017] According to an embodiment of the present invention, in a split free-piston Stirling engine with a common cavity and opposed to each other, a linear motor is further provided outside the cold cylinder for driving the linear motor to generate electricity through the reciprocating movement of the power piston.

[0018] According to the split free-piston Stirling engine with a common cavity and opposed to each other in one embodiment of the present invention, the valve piston and the power piston reciprocate in the hot cylinder and the cold cylinder respectively with a preset phase difference.

[0019] According to an embodiment of the present invention, for a split free-piston Stirling engine with opposing common cavities, the preset ideal value of the phase difference is 90 degrees.

[0020] The embodiment of the present invention provides a split free-piston Stirling engine with a common cavity and an opposing body. The first back-pressure cavity on the side of the valve piston away from the hot cavity and the second back-pressure cavity on the side of the power piston away from the first cold cavity are interconnected, thereby ensuring that the gas forces exerted on each power piston or valve piston during movement are the same, and then the vibration effects generated by each valve piston and power piston during movement will offset each other, reducing the vibration during engine operation. The valve pistons and power pistons that are arranged opposite to each other act simultaneously. When the total output power is the same, the displacement of the power piston and the valve piston is significantly reduced compared to an engine with a single piston. Therefore, the vibration force generated by the power piston and the valve piston is also greatly reduced. Moreover, because the movement stroke of the power piston and the valve piston is reduced, the structural size of the engine is reduced, and thus the life and reliability of the elastic parts of the power piston and the valve piston can also be improved, thereby increasing the operating frequency of the engine and enabling the engine to achieve higher output with a more compact structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a structural schematic diagram of an embodiment of a split free-piston Stirling engine with opposing common cavities according to the present invention;

[0023] Figure 2 It is a structural schematic diagram of another embodiment of the split free-piston Stirling engine with opposing common cavities of the present invention;

[0024] Figure 3 It is a structural schematic diagram of a third embodiment of a split free-piston Stirling engine with opposing common cavities according to the present invention;

[0025] Figure 4 It is a structural schematic diagram of a fourth embodiment of a split free-piston Stirling engine with opposing common cavities according to the present invention;

[0026] Figure 5 It is a structural schematic diagram of a fifth embodiment of a split free-piston Stirling engine with opposing common cavities according to the present invention;

[0027] Reference numerals:

[0028] 10, hot cylinder; 110, gas distribution piston; 1110, hot chamber; 1120, first back pressure chamber; 1130, gas distribution piston rod; 120, partition; 130, gas distribution piston leaf spring; 140, second cold chamber; 150, heater; 160, regenerator; 170, cooler;

[0029] 20, cold cylinder; 210, power piston; 2110, first cold chamber; 2120, second back pressure chamber; 2130, power piston rod; 220, power piston leaf spring; 230, linear motor;

[0030] 30. Connecting pipe;

[0031] 40. Pressure stabilizing pipeline. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0034] Combine the following Figures 1 to 5The present invention provides a split free-piston Stirling engine with a common cavity, comprising at least one group of hot cylinders 10 and at least one group of cold cylinders 20. The at least one group of hot cylinders 10 is provided with a plurality of valve pistons 110 that are opposed to each other in pairs, and the at least one group of cold cylinders 20 is provided with a plurality of power pistons 210 that are opposed to each other in pairs. A single valve piston 110 or multiple groups of valve pistons 110 are provided with a hot cavity 1110, and a first back-pressure cavity 1120 is provided on a side of the valve piston 110 away from the hot cavity 1110; a single power piston 210 or multiple groups of power pistons 210 are provided with a first cold cavity 2110, and a side of the power piston 210 away from the first cold cavity 2110 is a second back-pressure cavity 2120 that is connected to the first back-pressure cavity 1120.

[0035] Specifically, the number of the gas distribution pistons 110 and the power pistons 210 is not limited herein. For example, there may be two oppositely arranged gas distribution pistons 110 and two oppositely arranged power pistons 210, two oppositely arranged gas distribution pistons 110 corresponding to four oppositely arranged power pistons 210, four oppositely arranged gas distribution pistons 110 corresponding to two oppositely arranged power pistons 210, or four oppositely arranged gas distribution pistons 110 corresponding to four oppositely arranged power pistons 210.

[0036] In one embodiment of the present invention, for the gas distribution piston 110, a partition plate 120 and a gas distribution piston leaf spring 130 are provided at one end of one gas distribution piston 110 away from the other gas distribution piston 110 arranged opposite. The partition plate 120 is connected to the hot cylinder 10, and a gas distribution piston rod 1130 is provided on the gas distribution piston 110. The gas distribution piston 110 is connected to the gas distribution piston rod 1130 and the hot cylinder 10. When the gas distribution piston 110 reciprocates in the hot cylinder 10, the gas distribution piston rod 1130 drives the gas distribution piston leaf spring 130 to deform. It should be noted that the "leaf spring" in the above embodiment can be a combination of other forms of springs (such as column springs, magnetic springs) and other supports (such as gas bearings, magnetic bearings), which is not limited here.

[0037] For the power piston 210, a power piston leaf spring 220 is provided at one end of one power piston 210 away from the other power piston 210 arranged oppositely, a power piston rod 2130 is provided on the power piston 210, and the power piston leaf spring 220 is connected with the power piston rod 2130 and the cold air cylinder 20. That is, when the power piston 210 reciprocates in the cold air cylinder 20, the power piston rod 2130 drives the power piston leaf spring 220 to deform.

[0038] A second cold chamber 140 is provided between the gas distribution piston 110 and the partition plate 120, and a connecting pipe 30 is provided between the hot cylinder 10 and the cold cylinder 20. One end of the connecting pipe 30 is connected to the second cold chamber 140, and the other end of the connecting pipe 30 is connected to the first cold chamber 2110, that is, the first cold chamber 2110 and the second cold chamber 140 are in a connected state. Therefore, when the opposite gas distribution piston 110 compresses the hot chamber 1110, the gas in the second cold chamber 140 can move toward the first cold chamber 2110.

[0039] A heater 150 is also provided outside the hot cylinder 10, one end of the heater 150 is connected to the hot chamber 1110, the other end of the heater 150 is connected to the regenerator 160 and the cooler 170, one end of the cooler 170 is connected to the regenerator 160, and the other end is connected to the second cold chamber 140. The heater 150 is used to transfer heat to the hot chamber 1110 to form gas pressure to push the gas distribution piston 110 and the power piston 210 to move. The regenerator 160 is used for isochoric heat absorption and isochoric heat release.

[0040] The hot cylinder 10 and the cold cylinder 20 are provided with a pressure-stabilizing pipe 40, which is connected to the first back-pressure chamber 1120 and the second back-pressure chamber 2120 respectively. The setting of the pressure-stabilizing pipe 40 is used to make the gas force on each opposing power piston 210 or gas distribution piston 110 the same during the movement, which helps to ensure the consistency of the movement state of each power piston 210 or gas distribution piston 110. The function of the pressure-stabilizing pipe 40 is to connect all the first back-pressure chambers 1120 or the second back-pressure chambers 2120 together, and can also connect all the first back-pressure chambers 1120 and the second back-pressure chambers 2120 together at the same time, so that the gas force on each opposing power piston 210 or gas distribution piston 110 during the movement is the same.

[0041] Furthermore, a linear motor 230 is also provided outside the cooling cylinder 20. During the reciprocating motion of the power piston 210, there is a relative motion between the linear motor 230 and the power piston 210, thereby generating a change in magnetic flux and outputting electrical energy.

[0042] The distribution piston 110 and the power piston 210 reciprocate in the hot cylinder 10 and the cold cylinder 20 respectively with a preset phase difference.

[0043] Please continue to refer to Figure 1 In one embodiment of the present invention, the working principle is first described below by taking two gas distribution pistons 110 corresponding to two power pistons 210:

[0044] It should be noted that the two gas distribution pistons 110 and the two power pistons 210 are coupled by gas force, and the two gas distribution pistons 110 and the two power pistons 210 are respectively located in the hot cylinder 10 and the cold cylinder 20. The farthest relative distance between the two gas distribution pistons 110 corresponds to the far end points of the two gas distribution pistons 110, and the shortest relative distance between the two gas distribution pistons 110 corresponds to the near end points of the two gas distribution pistons 110. Similarly, the farthest relative distance between the two power pistons 210 corresponds to the far end points of the two power pistons 210, and the shortest relative distance between the two power pistons 210 corresponds to the near end points of the two power pistons 210.

[0045] In the initial state, the two gas distribution pistons 110 are located near the far end point, and the two power pistons 210 are located near the near end point. The hot chamber 1110 receives the external heat of the heater 150, and the high-pressure gas expands due to the heat, pushing the power piston 210 to move toward the far end point until it is close to the far end point. When the power piston 210 moves toward the far end point, the gas pressure in the working chamber decreases, the pressure difference between the working chamber and the back pressure chamber decreases, the gas force on the gas distribution piston 110 decreases, and the elastic force of the gas distribution piston leaf spring 130 pushes the gas distribution piston 110 to move toward the near end point. During the movement of the two gas distribution pistons 110 toward the near end point, the gas in the hot chamber 1110 is pushed to pass through the regenerator 160, the cooler 170 and the second cold chamber 140 in turn to be transported to the first cold chamber 2110, and the hot gas completes isochoric heat release in the regenerator 160, and transfers the heat to the metal filler in the regenerator 160. The two valve pistons 110 move to the near stop point and reverse to start moving toward the far stop point. At the same time, the two power pistons 210 move toward the near stop point. The gas is compressed in the first cold chamber 2110, and the compression heat is dissipated outward through the cooler 170, thereby realizing the isothermal compression process. Finally, when the power piston 210 reaches the near stop point and starts moving toward the far stop point, the two valve pistons 110 continue to move from the near stop point to the far stop point, pushing the working fluid gas from the first cold chamber 2110 through the regenerators 160 on both sides into the hot chamber 1110. The gas completes the isochoric heat absorption process in the regenerator 160, and the temperature rises after absorbing heat from the metal filler in the regenerator 160. Then, the two power pistons 210 can continue to move toward the far stop point and perform the isothermal expansion process. The gas in the engine can then start the next cycle, and so on. In the above cycle, the movement of the two valve pistons 110 always leads the two power pistons 210 by nearly 90 degrees.

[0046] That is, during the operation of the engine, the moving parts perform approximately sinusoidal motion, and the back pressure chambers of the engine are connected to each other, so that during the operation of the engine, each pair of power pistons 210 or valve pistons 110 are subjected to the same gas force and have exactly the same motion state. The power pistons 210 and valve pistons 110 are arranged opposite each other in pairs, so that the output result of the superposition of two sinusoidal waves with the same amplitude and opposite phase is 0, and the vibrations generated by the movement of each pair of power pistons 210 or valve pistons 110 cancel each other out, so that the vibration force of the entire engine system is 0, thereby achieving low vibration and high reliability operation of the entire system.

[0047] Please refer to Figure 2 In another embodiment of the present invention, the two power pistons 210 disposed opposite to each other may not share the first cold chamber 2110. For example, when the two power pistons 210 do not share the first cold chamber 2110, a connecting pipe 30 is provided between the second cold chamber 140 and the first cold chamber 2110 for connection. Figure 3 , it is also possible to prevent the two gas distribution pistons 110 from sharing a hot chamber.

[0048] Please refer to Figure 4 and Figure 5 In other embodiments of the present invention, four gas distribution pistons 110 and two power pistons 210 may be provided. For example, the four gas distribution pistons 110 are arranged opposite to each other in pairs, and a heater 150, a heat regenerator 160 and a cooler 170 are arranged outside each gas distribution piston 110. Alternatively, in other embodiments, four gas distribution pistons 110 and two power pistons 210 or four power pistons 210 may be provided. The four power pistons 210 are arranged opposite to each other in pairs. The specific operating principle can be referred to the above description, which will not be repeated here.

[0049] In summary, the split free piston Stirling engine with a common cavity and opposed to each other provided by the present invention, through the gas coupling effect, allows two valve pistons 110 to share a hot cavity 1110, and two power pistons 210 to share a first cold cavity 2110, thereby reducing the number of hot cavities 1110 and first cold cavities 2110 in the engine, making the structure more compact, and at the same time helping to reduce heat loss during the operation of the engine, improve the thermal efficiency of the engine, and the power piston 210 and valve piston 110 of the engine are separately placed in two cylinders, that is, the hot cylinder 10 and the cold cylinder 20, reducing the interference between the two vibration systems. Moreover, the two valve pistons 110 and the two power pistons 210 are arranged symmetrically in pairs, and during the operation of the engine, the vibration directions of each pair of power pistons 210 and valve pistons 110 are opposite, and the vibrations cancel each other out, effectively reducing the vibration of the entire engine system, and the back pressure cavities in the engine are connected to each other, more effectively ensuring the consistency of the gas force and motion state of each pair of power pistons 210 and valve pistons 110. At the same time, since there are two pairs of valve pistons 110 and power pistons 210 acting simultaneously in the engine, when the total output power is the same, the displacement of the valve piston 110 and the power piston 210 is significantly reduced compared to the traditional free piston Stirling engine, so the vibration force of the power piston 210 and the valve piston 110 is also significantly reduced. In addition, due to the reduction in the movement stroke of the piston, the life and reliability of the power piston leaf spring 220 supporting the power piston 210 and the valve piston leaf spring 130 supporting the valve piston 110 can also be significantly improved. The structural size of the engine is reduced and the operating frequency is increased, so that higher output can be achieved in a more compact structure.

[0050] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0051] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A split free piston Stirling engine with common cavity opposed to each other, characterized in that: include: At least one set of hot cylinders, each of which is provided with a plurality of gas distribution pistons which are arranged opposite to each other; At least one group of cold cylinders, each of which is provided with a plurality of power pistons disposed opposite to each other; A single gas distribution piston or a plurality of groups of gas distribution pistons are provided with a hot cavity, and a first back pressure cavity is provided on a side of the gas distribution piston away from the hot cavity; a single power piston or a plurality of groups of power pistons are provided with a first cold cavity, and a side of the power piston away from the first cold cavity is a second back pressure cavity connected to the first back pressure cavity; One end of the gas distribution piston away from the other gas distribution piston arranged oppositely is provided with a partition plate and a gas distribution piston leaf spring; The partition is connected to the hot cylinder, the gas distribution piston is provided with a gas distribution piston rod, and the gas distribution piston leaf spring is connected to the gas distribution piston rod and the hot cylinder; One end of the power piston away from the other power piston arranged opposite to it is provided with a power piston leaf spring; The power piston is provided with a power piston rod, and the power piston leaf spring is connected to the power piston rod and the cold cylinder; A second cold chamber is provided between the gas distribution piston and the partition plate; A connecting pipe is provided between the hot cylinder and the cold cylinder, one end of the connecting pipe is connected to the second cold chamber, and the other end of the connecting pipe is connected to the first cold chamber.

2. The split free piston Stirling engine with common cavity and opposed cavity according to claim 1, characterized in that: A heater is also provided outside the hot cylinder, one end of the heater is connected to the hot chamber, the other end of the heater is connected to a regenerator and a cooler, one end of the cooler is connected to the regenerator, and the other end is connected to the second cold chamber.

3. The split free piston Stirling engine with common cavity and opposed cavity according to claim 2, characterized in that: The hot cylinder and the cold cylinder are provided with pressure-stabilizing pipes outside, and the pressure-stabilizing pipes are respectively connected to the first back-pressure chamber and the second back-pressure chamber, so that all the first back-pressure chamber and the second back-pressure chamber are in a connected state.

4. The split free-piston Stirling engine with common cavities and opposed chambers according to claim 1, characterized in that: A linear motor is also provided outside the cooling cylinder, which is used to drive the linear motor to generate electricity through the reciprocating movement of the power piston.

5. The split free-piston Stirling engine with common cavities and opposed chambers according to claim 1, characterized in that: The distribution piston and the power piston reciprocate in the hot cylinder and the cold cylinder respectively with a preset phase difference.

6. The split free-piston Stirling engine with common cavities facing each other according to claim 5, characterized in that: The preset phase difference is 90 degrees.

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