Reciprocating compressor and refrigerator

Abstract

The utility model relates to the field of compressors, and provides a reciprocating compressor and a refrigerator. The reciprocating compressor comprises an air cylinder, a piston, an air supplementing opening and an air supplementing valve, the air cylinder comprises a side wall and an end cover, and the end cover is arranged at one end of the side wall and provided with an air inlet and an air outlet; the piston reciprocates in the air cylinder, and a cavity used for compressing gas is defined by the side wall, the end cover and the piston. The air supply port can be flexibly arranged on the end cover or the piston, and the air supply valve is arranged on the air supply port to control opening and closing of the air supply port. Opening and closing of the air supplementing opening can be controlled through the air supplementing valve, specifically, the air supplementing opening is opened only at the appropriate time, and therefore the air supplementing pressure loss is reduced.

Description

Reciprocating compressors and refrigerators Technical Field

[0001] This utility model relates to the field of compressors, specifically to a reciprocating compressor and a refrigerator. Background Technology

[0002] Jet enthalpy enhancement technology is a technique that improves compressor performance, particularly its heating capacity in low-temperature environments, by injecting intermediate-pressure refrigerant gas during the compression process. It is primarily used in scroll compressors and is widely applied in large-scale low-temperature heating equipment such as air conditioners and heat pumps.

[0003] Chinese patent CN108071590A discloses a cylinder compressor that utilizes an independent reciprocating compression chamber to actively draw in and compress intermediate-temperature vapor. This applies the concept of jet enthalpy enhancement technology to a refrigerator's refrigeration system, constructing an independent compression refrigeration cycle matched to the refrigerator's system, thus improving adaptability under all operating conditions and energy efficiency. However, the gas inlet of this cylinder compressor is located on the cylinder side wall. During gas replenishment, to avoid backflow, the gas inlet needs to be positioned near the piston's bottom dead center on the side wall, limiting both the gas replenishment pressure range and the amount of gas replenished. Furthermore, this location results in the cylinder pressure being only slightly higher than the intake pressure during gas replenishment, leading to significant pressure loss, low thermodynamic efficiency, and limited energy efficiency improvement. Summary of the Invention

[0004] To address the above problems, one aspect of this utility model provides a reciprocating compressor that can ensure a suitable gas supply pressure range and gas supply volume, while reducing gas supply pressure loss.

[0005] The first aspect of this utility model provides a reciprocating compressor, including a cylinder, a piston, a gas inlet, and a gas inlet valve. The cylinder includes a side wall and an end cover. The end cover is disposed at one end of the side wall and has an air inlet and an air outlet. The piston reciprocates within the cylinder. The side wall, the end cover, and the piston form a chamber for compressing gas. The gas inlet is disposed on the end cover or the piston. The gas inlet valve is disposed on the gas inlet and controls the opening and closing of the gas inlet.

[0006] Optionally, the gas replenishment valve is an electrically controlled valve, and the reciprocating compressor also includes a control unit, which controls the opening and closing of the gas replenishment valve by sending a timing control signal to the gas replenishment valve.

[0007] Optionally, the air supply valve is a non-electrically controlled valve, which is connected to the crankshaft that drives the piston.

[0008] Optionally, the air supply valve is a non-electrically controlled valve, which is connected to the piston.

[0009] Optionally, it also includes a pressure sensor to detect the air pressure in the chamber, and the air supply valve opens or closes according to the detected air pressure.

[0010] Optionally, the air replenishment valve includes a push rod, a first spring, a second spring, a first pressure diaphragm, and a second pressure diaphragm. The push rod has a through hole corresponding to the air replenishment port. The first spring is disposed on one side of the push rod. One end of the first spring is connected to the push rod, and the other end is connected to the first pressure diaphragm. The first pressure diaphragm communicates with the side of the air replenishment port away from the chamber. The second spring is disposed on the side of the push rod opposite to the first spring. One end of the second spring is connected to the push rod, and the other end is connected to the second pressure diaphragm. The second pressure diaphragm communicates with the chamber.

[0011] Optionally, the opening and closing of the air supply valve is synchronized with the reciprocating motion of the piston.

[0012] The second aspect of this utility model provides a refrigerator, including a first refrigeration circuit and a second refrigeration circuit. The first refrigeration circuit is composed of a reciprocating compressor, a condenser, a throttling element for the refrigerator compartment, and an evaporator for the refrigerator compartment connected in sequence. The second refrigeration circuit is composed of a reciprocating compressor, a condenser, a throttling element for the freezer compartment, and an evaporator for the freezer compartment connected in sequence. The reciprocating compressor includes a cylinder, a piston, a gas inlet, and a gas inlet valve. The cylinder includes a side wall and an end cover. The end cover is located at one end of the side wall and has an inlet and an outlet. The inlet is connected to the refrigerant outlet of the freezer compartment evaporator, and the outlet is connected to the refrigerant inlet of the condenser. The piston reciprocates within the cylinder, and the side wall, end cover, and piston form a chamber for compressing gas. The gas inlet is located on the end cover or the piston and is connected to the refrigerant outlet of the refrigerator compartment evaporator. The gas inlet valve is located at the gas inlet and controls the opening and closing of the gas inlet.

[0013] Beneficial effects

[0014] By adding a gas replenishment valve, the reciprocating compressor can be controlled to replenish gas primarily within the effective replenishment zone. Furthermore, the location of the gas replenishment port becomes more flexible, no longer limited to placement on the side wall. Moreover, even if the gas replenishment port is located on the side wall, it does not need to be positioned near the piston's bottom dead center, effectively increasing the replenishment pressure range and gas volume. Attached Figure Description

[0015] Figure 1 is a schematic diagram of the reciprocating compressor in one embodiment of this utility model.

[0016] Figure 2 is a diagram of the refrigerant flow system of a refrigerator.

[0017] Figure 3 is a schematic diagram showing the changes of various parameters of a reciprocating compressor in one or more embodiments of the present invention during one cycle of piston reciprocating motion.

[0018] Figure 4 is a structural schematic diagram of a reciprocating compressor provided in some embodiments of this utility model.

[0019] Figure 5 is a schematic diagram of some embodiments of this utility model in which a ball valve is used as a gas supply valve to achieve precise control of the switching timing.

[0020] Figure 6 shows a gas supply valve, similar to a ball valve, which can be opened and closed within a specific angle range, provided in some embodiments of this utility model.

[0021] Figure 7 shows an air supply valve provided in some other embodiments of this utility model, which can be linked with the crankshaft and can be opened and closed at a specific angle or stroke range.

[0022] Figure 8 is a structural schematic diagram of a reciprocating compressor provided in some embodiments of this utility model.

[0023] Figure 9 is a structural schematic diagram of a reciprocating compressor provided in some other embodiments of this utility model.

[0024] Figure 10 is a schematic diagram of the pressure control mechanism in some embodiments of this utility model. By detecting the pressure inside the cylinder and cooperating with feedback control, the mechanism aims to replenish air in the effective air replenishment zone as much as possible, while avoiding replenishing air in the ineffective air replenishment zone.

[0025] Figure 11 shows the structure of the air supply valve for implementing pressure feedback control in some embodiments of this utility model.

[0026] Figure label:

[0027] Reciprocating compressor 100; cylinder 102; piston 104; crankshaft 106; connecting rod 108; air inlet 110; air outlet 112; side wall 114; air inlet 116; air inlet valve 118; end cover 120; chamber 122; refrigeration system 200; first refrigeration circuit 201; second refrigeration circuit 202; refrigerator compartment evaporator 204; freezer compartment evaporator 205; condenser 206; refrigerator compartment throttling element 207; freezer compartment throttling element 208; valve stem 301; ball 303; valve body 305; airflow passage 307; opening 309; passage structure 311; movable part 313; push rod 402; first spring 404; second spring 406; first pressure diaphragm box 408; second pressure diaphragm box 410; through hole 412. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] One or more embodiments of this utility model provide a reciprocating compressor 100. Figure 1 is a structural schematic diagram of the reciprocating compressor 100 in one embodiment of this utility model.

[0030] Referring to Figure 1, the reciprocating compressor 100, also known as a cylinder compressor, includes a cylinder 102, a piston 104, a crankshaft 106, and a connecting rod 108. The piston 104 is disposed within the cylinder 102 and can reciprocate in the vertical direction within the chamber 122 of the cylinder 102, as shown in Figure 1. The vertical movement of the piston 104 is driven by the crankshaft 106 via the connecting rod 108. The crankshaft 106 is driven to rotate by a motor (not shown), and the connecting rod 108 converts the rotation of the crankshaft 106 into the vertical movement of the crankshaft 106.

[0031] At the end of cylinder 102 furthest from crankshaft 106 (top of cylinder 102 in Figure 1), an intake port 110 and an exhaust port 112 are provided, and a supplementary air port 116 is provided on one side wall 114. An intake valve is provided on the intake port 110, and an exhaust valve is provided on the exhaust port 112. The piston 104 can move upward within cylinder 102 to the top point where it abuts against the intake port 110 and the exhaust port 112, i.e., top dead center, to expel all the gas inside cylinder 102 through the exhaust port 112. It can also move downward to the bottom dead center located below the supplementary air port 116, thus completing the intake of air from the intake port 110 or the supplementary air port 116.

[0032] One cycle of the reciprocating motion of piston 104 includes a downward stroke from the top in Figure 1. During this stroke, piston 104 moves downward, the gas inside cylinder 102 expands, and the gas pressure decreases. When it reaches the appropriate position, intake port 110 opens, and refrigerant enters chamber 122 inside cylinder 102 through intake port 110. After completing the intake process, piston 104 moves upward again, and both intake port 110 and exhaust port 112 close. After piston 104 compresses the internal refrigerant, exhaust port 112 opens at the appropriate time, and piston 104 continues to move upward, expelling the compressed internal refrigerant through exhaust port 112, completing one cycle of reciprocating motion.

[0033] In one or more embodiments of this utility model, the reciprocating compressor 100 has a make-up air valve 118, which is disposed at the make-up air port 116 and can open and close the make-up air port 116 synchronously with the reciprocating motion of the piston 104. In particular, by opening and closing the make-up air port 116 at appropriate times, the pressure loss of the make-up air is reduced and the energy-saving effect is improved. The specific timing for opening and closing the make-up air port 116 will be described in detail later.

[0034] The following description, in conjunction with Figure 2, introduces an applicable device for the reciprocating compressor 100 in one or more embodiments of this utility model. Figure 2 is a refrigerant flow diagram of a refrigerator's refrigeration system 200.

[0035] Referring to Figure 2, the refrigerator's refrigeration system 200 includes a first refrigeration circuit 201 and a second refrigeration circuit 202. The evaporator of the first refrigeration circuit 201 is located in the position corresponding to the refrigerator compartment and is used to cool the refrigerator compartment; it is called the refrigerator compartment evaporator 204. The evaporator of the second refrigeration circuit 202 is located in the position corresponding to the freezer compartment and is used to cool the freezer compartment; it is called the freezer compartment evaporator 205. The two refrigeration circuits share the compressor section and the condenser section 206.

[0036] Specifically, the first refrigeration circuit 201 is composed of a reciprocating compressor 100, a condenser 206, a refrigerator compartment throttling element 207 (capillary tube), and a refrigerator compartment evaporator 204 connected in sequence. The second refrigeration circuit 202 is composed of a reciprocating compressor 100, a condenser 206, a freezer compartment throttling element 208 (capillary tube), and a freezer compartment evaporator 205 connected in sequence. In the first refrigeration circuit 201, the refrigerant outlet of the refrigerator compartment evaporator 204 is connected to the gas inlet 116 of the reciprocating compressor 100. In the second refrigeration circuit 202, the refrigerant outlet of the freezer compartment evaporator 205 is connected to the gas inlet 110 of the reciprocating compressor 100. The refrigerant inlet of the condenser 206 is connected to the exhaust port 112 of the reciprocating compressor 100.

[0037] By applying one or more reciprocating compressors 100 of this invention to the refrigeration system 200 of the refrigerator described above, a single reciprocating compressor 100 can provide two evaporation temperatures, with the lower temperature applied to the freezer compartment evaporator 205 and the higher temperature applied to the refrigerator compartment evaporator 204. The appropriate degree of compression work can be performed as needed, thereby improving the thermodynamic perfection of the system.

[0038] Figure 3 is a schematic diagram showing the changes in various parameters of a reciprocating compressor 100 in one or more embodiments of the present invention during one cycle of the reciprocating motion of the piston 104.

[0039] Referring to Figure 3, one cycle of the reciprocating motion of piston 104 includes the following sequential strokes: expansion stroke, intake stroke, compression stroke, and exhaust stroke. Specifically, the expansion stroke corresponds to the range of motion of piston 104 from top dead center to the opening of intake port 110; the intake stroke corresponds to the range of motion of piston 104 from the opening of intake port 110 to the bottom dead center of piston 104; the compression stroke corresponds to the range of motion of piston 104 from the bottom dead center to the opening of exhaust port 112; and the exhaust stroke corresponds to the range of motion of piston 104 from the opening of exhaust port 112 to the top dead center of piston 104.

[0040] In one or more embodiments of this invention, during the reciprocating motion of the piston 104, the crankshaft 106 maintains a constant rotational speed, i.e., the crankshaft 106 rotates at a constant speed, and the crankshaft angle increases linearly from 0° to 360°. For ease of explanation, in this text, crankshaft angles 0° and 360° correspond to the top dead center of the piston 104, and 180° corresponds to the bottom dead center of the piston 104. In other embodiments, the correspondence and numerical expression can be flexibly adjusted as needed, and are not limited thereto.

[0041] During the uniform rotation of crankshaft 106, the working volume of cylinder 102 first increases and then decreases. The pressure Pin inside cylinder 102 changes as shown by the bottom curve in Figure 3. During the expansion stroke, the pressure inside cylinder 102 gradually decreases. When entering the intake stroke, intake port 110 opens, and the pressure inside intake port 110 and cylinder 102 are balanced, with the pressure inside cylinder 102 being approximately equal to the intake pressure. When entering the compression stroke, intake port 110 and exhaust port 112 close, and as piston 104 compresses and performs work, the pressure inside cylinder 102 gradually increases. When entering the exhaust stroke, exhaust port 112 opens, and the pressure inside cylinder 102 and exhaust passage are balanced, with the pressure inside cylinder 102 being approximately equal to the exhaust pressure.

[0042] In some embodiments of this utility model, the air replenishment valve 118 can control air replenishment to occur only in the effective air replenishment zone, while not in the ineffective air replenishment zone, thereby reducing air replenishment pressure loss and improving energy-saving effect. Specifically, the effective air replenishment zone is the area in the compression stroke that is lower than the air replenishment pressure but higher than the intake pressure, preferably an area that is higher than the intake pressure by a specified pressure value but lower than the air replenishment pressure. The specified pressure value can be, for example, half of the difference between the air replenishment pressure and the intake pressure.

[0043] The ineffective air replenishment zone includes multiple areas during the expansion stroke, intake stroke, and compression stroke. In the solution disclosed in patent CN108071590A, because the timing of air replenishment at the air replenishment port 116 is not controlled, the opening and closing of the air replenishment port 116 is achieved solely by the blocking / unblocking of the air replenishment port 116 during the reciprocating motion of the piston 104. Air replenishment also occurs during certain time periods in the expansion and intake strokes (specifically, in areas where the pin pressure is lower than the air replenishment pressure during the expansion and intake strokes). This portion of air replenishment results in significant pressure loss, which is detrimental to energy efficiency. In some embodiments of this utility model, by prohibiting air replenishment in these ineffective air replenishment zones, especially during the time when the piston 104 does not separate the chamber 122 from the air replenishment port 116, the air replenishment pressure loss can be effectively reduced, thereby improving system energy efficiency.

[0044] Specifically, in some embodiments, during one opening and closing cycle of the supplementary air valve 118, the supplementary air valve 118 is closed for at least a portion of the time corresponding to the intake stroke of the piston 104. Furthermore, during one opening and closing cycle of the supplementary air valve 118, the supplementary air valve 118 is closed for the entire time corresponding to the intake stroke of the piston 104. In some embodiments, during one opening and closing cycle of the supplementary air valve 118, the supplementary air valve 118 is closed for the entire time corresponding to the expansion stroke of the piston 104. By using the supplementary air valve 118 to prohibit air supply to the cylinder 102 during these ineffective air supply periods, the air supply pressure loss can be effectively reduced, and the system energy efficiency can be improved.

[0045] The ineffective air replenishment zone may also include a portion of the piston 104's compression stroke, specifically the period when the pressure inside cylinder 102 is only slightly higher than the intake pressure; in other words, the initial stage of the compression stroke. In some embodiments, the air replenishment valve 118 can be closed during this portion of the compression stroke by controlling its opening and closing sequence, thereby avoiding the air replenishment pressure loss during this period and improving system efficiency.

[0046] In some embodiments, 0° and 360° of crankshaft angle correspond to the state where piston 104 is at top dead center, and 180° of crankshaft angle corresponds to the state where piston 104 is at bottom dead center. The air supply valve 118 opens when the crankshaft angle is within the range of (θ1, θ2). In some embodiments, 180° ≤ θ1 ≤ θ2 ≤ 320°.

[0047] In other embodiments, the opening and closing of the air supply valve 118 can also be controlled by a pressure control mechanism based on Pin. For example, the air supply valve 118 can be opened to supply air when the pressure Pin in the cylinder 102 is higher than the intake pressure by a specified pressure value. The specified pressure value can be, for example, half of the difference between the air supply pressure and the intake pressure.

[0048] The following describes some mechanisms and control methods for controlling the opening and closing sequence of the air replenishment valve 118, including a timing control mechanism and a pressure control mechanism. The timing control mechanism controls the opening and closing of the air replenishment valve 118 according to a preset or feedback-controlled timing sequence; the pressure control mechanism controls the opening and closing of the air replenishment valve 118 according to the pressure in the internal chamber 122 of the cylinder 102. Both mechanisms can ensure that air replenishment is performed as much as possible in the effective air replenishment area and avoids air replenishment in the ineffective air replenishment area, thereby reducing air replenishment pressure loss and improving energy efficiency. It should be noted that the following description is only exemplary and does not include all methods that can control the opening and closing sequence of the air replenishment valve 118. Other suitable mechanisms and methods for controlling the opening and closing sequence of the air replenishment valve 118 not listed should be included within the scope of this utility model embodiment, and will not be elaborated here.

[0049] Figure 4 is a schematic diagram of the reciprocating compressor 100 provided in some embodiments of this utility model. Referring to Figure 4, the reciprocating compressor 100 uses a solenoid valve as a make-up air valve 118, and uses a timing control signal to control the opening and closing of the make-up air valve 118. The timing control signal can be preset, or it can be feedback control based on the detection of sensors.

[0050] The sensor can be a pressure sensor that detects the pressure inside the cylinder 102, or a Hall sensor, magnetoelectric sensor, etc., that detects the crankshaft angle of the crankshaft 106. In some embodiments, the timing control signal can also be obtained by processing a signal reflecting the motor rotation angle obtained from the motor. In other embodiments, the sensor can be a sensor that detects the on / off state of the intake port 110 and the exhaust port 112, a sensor that detects the travel stroke of the piston 104, or a combination of the above types of sensors; this embodiment of the present invention is not limited to these types.

[0051] By detecting crankshaft angle, cylinder 102 internal pressure, or other parameters, in some embodiments of this invention, the control unit, which is communicatively connected to the sensor, can calculate the current motion state of the piston 104, specifically which stroke it is in during reciprocating motion and its position within that stroke. Based on this stroke and position determination, a timing control signal can be set to control the solenoid valve to replenish air only in the effective replenishment zone, avoiding replenishment in the ineffective replenishment zone, thereby effectively reducing replenishment pressure loss and improving energy efficiency.

[0052] In other embodiments of this utility model, the reciprocating compressor 100 may also use any other form of electrically controlled valve, such as an electronic expansion valve, which can be precisely controlled by timing control signals as the gas supply valve 118. This utility model does not limit this.

[0053] In other embodiments of this utility model, a non-electrically controlled valve can also be used as the air supply valve 118 to achieve periodic and precise control of the opening and closing timing of the air supply valve 118. Since the crankshaft 106 and the piston 104 rotate or reciprocate in the same period, the non-electrically controlled valve can be connected to the crankshaft 106 or the piston 104, and can achieve the purpose of opening and closing synchronously with the reciprocating motion of the piston 104.

[0054] Figure 5 is a schematic diagram of some embodiments of this utility model in which a ball valve is used as a gas supply valve 118 to achieve precise control of the opening and closing timing.

[0055] Referring to Figure 5, the ball valve includes a valve stem 301, a ball 303, and a valve body 305. The valve body 305 is disposed in an airflow channel 307 for supplying air to the air inlet 116. The ball 303 is disposed in the airflow channel 307 and has an opening 309 at its center. The ball 303 can be driven by the valve stem 301 to rotate within the valve body 305. Specifically, the valve stem 301 is connected to the crankshaft 106. The rotation of the crankshaft 106 drives the rotation of the valve stem 301, which in turn drives the rotation of the ball 303 within the valve body 305.

[0056] When the opening 309 rotates to an angle opposite to the airflow channel 307, the air supply valve 118 opens, connecting the airflow channel 307, allowing air to be supplied to the cylinder 102 via the air supply port 116. When the opening 309 rotates to an angle offset from the airflow channel 307, the air supply valve 118 closes, and the airflow channel 307 closes. In one or more embodiments of this utility model, the opening duration or angle range of the air supply valve 118 in each cycle can be adjusted by adjusting the size of the opening 309, the size of the airflow channel 307, etc.

[0057] In order to ensure that the air supply valve 118 supplies air only in the effective air supply area and avoids supplying air in the ineffective air supply area, in some embodiments of this utility model, the correspondence between the opening time of the air supply valve 118 and the effective air supply area can be achieved by accurately setting the structure and matching method of the connection mechanism (e.g., a coupling) between the valve stem 301 and the crankshaft 106.

[0058] Figure 6 illustrates a replenishing air valve 118, similar to a ball valve, provided in some embodiments of this utility model, capable of opening and closing within a specific angle range. The upper part of Figure 6 is a structural schematic diagram of the replenishing air valve 118, while the middle and lower parts are schematic diagrams of two critical switching states of the replenishing air valve 118. The replenishing air valve 118 includes a valve stem 301 and an airflow channel 307. The airflow channel 307 and the valve stem 301 are orthogonally arranged. The airflow channel 307 communicates with the replenishing air port 116, allowing replenishment of air to the cylinder 102 via the airflow channel 307 and the replenishing air port 116.

[0059] The end of the valve stem 301 has a hollow channel structure 311, which rotates as the valve stem 301 rotates. During a portion of the valve stem 301's rotation cycle, the channel structure 311 is opposite to the airflow channel 307, and the air supply port 116 is open during this period. During other portions of the valve stem 301's rotation cycle, the channel structure 311 and the airflow channel 307 are offset from each other, and the air supply port 116 is closed during this period.

[0060] In order to ensure that the air supply valve 118 supplies air only in the effective air supply area and avoids supplying air in the ineffective air supply area, in some embodiments of this utility model, the correspondence between the opening time of the air supply valve 118 and the effective air supply area can be achieved by accurately setting the structure and cooperation method of the connection mechanism between the valve stem 301 and the crankshaft 106.

[0061] Figure 7 illustrates an air supply valve 118 provided in some other embodiments of the present invention, which can be linked with the crankshaft 106 and opened and closed at a specific angle or stroke range. Referring to Figure 7, this type of air supply valve 118 includes a valve body 305 and a movable part 313. The valve body 305 has an airflow channel 307 communicating with the air supply port 116 and a track for the movable part 313 intersecting the airflow channel 307. Specifically, in some embodiments of the present invention, the airflow channel 307 and the track for the movable part 313 are orthogonally arranged.

[0062] The movable component 313 is connected to the crankshaft 106 or the piston 104 via the connecting rod 108, and can be driven by the crankshaft 106 or the piston 104 to reciprocate within its track. The movable component 313 has an opening 309 extending through the airflow passage 307. When the movable component 313 reciprocates within its track, the opening 309 is opposite to the airflow passage 307 for a portion of the time, and offset from it for another portion. When the opening 309 is opposite to the airflow passage 307, the air supply valve 118 opens, the airflow passage 307 opens, and air can be supplied to the cylinder 102 via the air supply port 116. When the opening 309 is offset from the airflow passage 307, the air supply valve 118 closes, and the airflow passage 307 closes.

[0063] In order to replenish air within the effective air replenishment zone as much as possible and avoid replenishing air in the ineffective air replenishment zone, in some embodiments of this utility model, the connection method between the movable part 313 and the crankshaft 106 and piston 104 can be accurately set to achieve the correspondence between the opening time of the air replenishment valve 118 and the effective air replenishment zone.

[0064] In some embodiments of this utility model, the reciprocating compressor 100 is provided with an additional air supply valve 118 at the air supply port 116, and the opening and closing of the air supply valve 118 is controlled synchronously with the stroke of the piston 104, so as to supply air only in the effective air supply area shown in Figure 3, and avoid supplying air in the ineffective air supply area, thereby effectively reducing the air supply pressure loss and improving energy efficiency.

[0065] Another advantage of this reciprocating compressor 100 is that the location of its air inlet 116 can be more flexible. Figure 8 is a structural schematic diagram of the reciprocating compressor 100 provided in some embodiments of this utility model. Referring to Figure 8, the cylinder 102 includes a side wall 114 and an end cover 120, with the end cover 120 located at the end of the side wall 114 near the top dead center. In some embodiments of this utility model, not only are the air inlet 110 and the exhaust port 112 located on the end cover 120, but the air inlet 116 is also located on the end cover 120. Due to the presence of the air inlet valve 118, the air inlet 116 no longer depends on the piston 104 blocking / unblocking the air inlet 116 to open or close, making the location of the air inlet 116 more flexible. It can supply air to the cylinder 102 through it during the effective air supply period.

[0066] Figure 9 is a structural schematic diagram of a reciprocating compressor 100 provided in some other embodiments of the present invention. Referring to Figure 9, in some embodiments of the present invention, the air supply port 116 may be disposed through the piston 104. During the expansion stroke and intake stroke, the air supply port 116 is closed by means of the air supply valve 118, while the air supply port 116 is opened only in the effective air supply area of ​​the compression stroke by means of the air supply valve 118.

[0067] In summary, by adding the supplementary air valve 118, not only can the reciprocating compressor 100 be controlled to supplement air primarily within the effective supplementary air zone, but the placement of the supplementary air port 116 can also be made more flexible, not limited to being located on the side wall 114. Furthermore, even if the supplementary air port 116 is located on the side wall 114, it does not need to be placed close to the bottom dead center of the piston 104, which can effectively improve the supplementary air pressure range and supplementary air volume.

[0068] The above describes an implementation of a timing control mechanism that can replenish gas in the effective gas replenishment zone as much as possible and avoid replenishing gas in the ineffective gas replenishment zone. In other embodiments of this utility model, a pressure control mechanism can also be used to achieve the same result.

[0069] Figure 10 is a schematic diagram of the pressure control mechanism in some embodiments of this utility model. By detecting the pressure inside the cylinder 102 and cooperating with feedback control, the mechanism aims to replenish air in the effective air replenishment area as much as possible, while avoiding replenishing air in the ineffective air replenishment area.

[0070] Referring to Figure 10, the pressure control mechanism may include a pressure sensor to detect the air pressure (i.e., the pressure Pin inside the cylinder 102) in the chamber 122 of the cylinder 102. The pressure sensor is communicatively connected to the controller of the reciprocating compressor 100. The controller is also communicatively connected to the air supply valve 118 and sends a feedback control signal to the air supply valve 118 to control the opening and closing of the air supply valve 118.

[0071] The controller is configured to control the opening and closing of the air supply valve 118 based on the detection results of the pressure sensor. It should be noted that "based on the detection results of the pressure sensor" does not limit the detection results to be the only factor in the decision. In some embodiments, the detection results of the pressure sensor can be combined with other factors to jointly determine whether to open or close the air supply valve 118.

[0072] In some implementations, the controller is configured to: open the air supply valve 118 when the pressure sensor's detection result corresponds to the air pressure range of the effective air supply zone; and close the air supply valve 118 when the pressure sensor's detection result does not correspond to the air pressure range of the effective air supply zone.

[0073] The effective air replenishment zone's pressure range (i.e., the specified range) has an upper limit and a lower limit. The upper limit is less than or equal to the air replenishment pressure at air replenishment port 116, and the lower limit is greater than the intake pressure at air inlet 110. In some embodiments, to increase the air replenishment pressure and reduce pressure loss, the lower limit can be increased. Specifically, the lower limit can be a specified pressure value higher than the intake pressure at air inlet 110. The specified pressure value can, for example, be half the difference between the air replenishment pressure and the intake pressure.

[0074] In some embodiments of this invention, if the opening and closing of the replenishing valve 118 is controlled solely based on the feedback from the pressure sensor's detection results, the replenishing valve 118 may open to replenish air during the expansion stroke of the piston 104. In some embodiments of this invention, the feedback control conditions can be added to prohibit the replenishing port 116 from replenishing air during the expansion stroke. Specifically, replenishment can be performed only on the rising edge of the air pressure, and not on the falling edge; in other words, replenishment is performed only during the compression stroke and not during the expansion stroke. For example, the currently collected air pressure value can be compared with the pressure value collected a specified time ago to determine whether the current pressure is rising or falling, and the opening and closing of the replenishing valve 118 can be controlled based on whether the air pressure range is within the effective replenishment zone. Specifically, when the pressure in chamber 122 is within the effective replenishment zone and the pressure in chamber 122 is rising, the replenishing valve 118 is controlled to open.

[0075] In some embodiments of this invention, the pressure control mechanism can control the opening and closing of the air supply valve 118, which is configured as an electrically controlled valve, based on a feedback control signal. In other embodiments, the pressure control mechanism can also be implemented using a mechanical structure.

[0076] Figure 11 shows the structure of the air supply valve 118 for pressure feedback control in some embodiments of this utility model. Referring to Figure 11, the pressure control mechanism includes a push rod 402, a first spring 404, a second spring 406, a first pressure diaphragm 408, and a second pressure diaphragm 410. The push rod 402 has a through hole 412 corresponding to the air supply port 116. The first spring 404 and the second spring 406 are respectively disposed on opposite sides of the push rod 402. One end of the first spring 404 abuts against the push rod 402, and the other end abuts against the first pressure diaphragm 408. The first pressure diaphragm 408 is connected to the side of the air supply port 116 away from the chamber 122, meaning that the air supply pressure Pm is applied to the first pressure diaphragm 408. One end of the second spring 406 abuts against the push rod 402, and the other end abuts against the second pressure diaphragm 410. The second pressure diaphragm 410 is connected to the chamber 122, meaning that the internal pressure Pin of the chamber 122 is applied to the second pressure diaphragm 410.

[0077] Based on force analysis, the position of push rod 402 can be controlled by the difference Pm-Pin between the air supply pressure and the internal pressure of chamber 122. Specifically, when Pm-Pin is within a specified range, the through hole 412 of push rod 402 is connected to the air supply port 116, and air supply begins. When Pm-Pin is outside the specified range, the through hole 412 of push rod 402 is misaligned with the air supply port 116, and air supply stops.

[0078] By appropriately selecting the first spring 404 and the second spring 406, and properly setting the size and position of the through hole 412, a pressure control mechanism can be implemented mechanically. This pressure control mechanism eliminates the need for electrical control components, utilizing a mechanical structure to complete pressure detection and feedback control, strictly preventing air replenishment backflow, and improving safety and stability. It should also be noted that the above mechanical implementation of the pressure control mechanism is merely an example; this invention does not limit the specific form of the pressure control mechanism, and it can also be implemented electrically.

[0079] It should be noted that in the embodiments of this utility model, opening the air supply valve 118 can be achieved by increasing the opening degree of the air supply valve 118, and closing the air supply valve 118 can be achieved by decreasing the opening degree of the air supply valve 118. These are equivalent in effect. As long as the air supply volume is increased in the effective air supply area and decreased in the ineffective air supply area, the same or similar effects can be achieved as in the embodiments exemplified in this utility model, reducing air supply pressure loss and improving energy efficiency.

[0080] The above are merely optional embodiments of this utility model and are not intended to limit this utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A reciprocating compressor, characterized in that, include: A cylinder includes a sidewall and an end cap, the end cap being disposed at one end of the sidewall and having an air inlet and an air outlet. A piston reciprocates within the cylinder, and the side wall, the end cap, and the piston together form a chamber for compressing gas; an air inlet is located on the end cap or the piston; an air inlet valve is located on the air inlet and controls the opening and closing of the air inlet.

2. The reciprocating compressor as described in claim 1, characterized in that, The gas replenishment valve is an electrically controlled valve, and the reciprocating compressor also includes a control unit. The control unit controls the opening and closing of the gas replenishment valve by sending a timing control signal to the gas replenishment valve.

3. The reciprocating compressor as described in claim 1, characterized in that, The air supply valve is a non-electrically controlled valve, and the non-electrically controlled valve is connected to the crankshaft that drives the piston.

4. The reciprocating compressor as described in claim 1, characterized in that, The air supply valve is a non-electrically controlled valve, and the non-electrically controlled valve is connected to the piston.

5. The reciprocating compressor as described in claim 1, characterized in that, It also includes a pressure sensor to detect the air pressure in the chamber, and the air supply valve opens or closes according to the detected air pressure.

6. The reciprocating compressor as described in claim 1, characterized in that, The air replenishment valve includes: a push rod having a through hole corresponding to the air replenishment port; a first spring disposed on one side of the push rod; a first pressure diaphragm, one end of the first spring being connected to the push rod and the other end being connected to the first pressure diaphragm, the first pressure diaphragm being in communication with the side of the air replenishment port away from the chamber; a second spring disposed on the side of the push rod opposite to the first spring; and a second pressure diaphragm, one end of the second spring being connected to the push rod and the other end being connected to the second pressure diaphragm, the second pressure diaphragm being in communication with the chamber.

7. The reciprocating compressor as described in any one of claims 1-6, characterized in that, The opening and closing of the air supply valve is synchronized with the reciprocating motion of the piston.

8. A refrigerator, characterized in that, include: The first refrigeration circuit consists of a reciprocating compressor, a condenser, a throttling element for the refrigerator compartment, and an evaporator for the refrigerator compartment connected in sequence. The second refrigeration circuit is composed of the reciprocating compressor, the condenser, the freezer compartment throttling element, and the freezer compartment evaporator connected in sequence. The reciprocating compressor includes: a cylinder, including a side wall and an end cover, the end cover being disposed at one end of the side wall, the end cover having an inlet and an outlet, the inlet being connected to the refrigerant outlet of the freezer compartment evaporator, and the outlet being connected to the refrigerant inlet of the condenser; a piston, reciprocating within the cylinder, the side wall, the end cover, and the piston forming a chamber for compressing gas; a gas inlet, disposed on the end cover or the piston, the gas inlet being connected to the refrigerant outlet of the freezer compartment evaporator; and a gas inlet valve, disposed on the gas inlet, controlling the opening and closing of the gas inlet.

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