CN116044712B - Ionic liquid compressor capable of controlling spraying to carry out liquid supplementing cooling by piston displacement and working method thereof - Google Patents

Abstract

The invention discloses an ionic liquid compressor for performing liquid supplementing cooling by piston displacement control spraying and a working method thereof. The position of the free piston is detected by a position detection unit to determine whether the compressor body is in an expansion phase, an intake phase, a compression phase or a discharge phase. During the expansion and suction phases, the pressure and temperature in the compressor body are relatively low, so that spray cooling is not necessary; in the exhaust stage of the compressor body, if continuous spraying is performed, sprayed ionic liquid spraying can directly flow away along with exhaust, so that unnecessary waste of the ionic liquid is caused, and therefore, the nozzle is accurately controlled to spray only in the compression process of the compressor, and efficient ionic liquid filling and enhanced heat exchange in the air cylinder are realized.

Description

Ionic liquid compressor with piston displacement controlled spray for liquid replenishment cooling and its working method

Technical Field

The invention belongs to the technical field of compressors, and in particular relates to an ionic liquid compressor for liquid replenishment cooling by controlling spraying with piston displacement and a working method thereof.

Background technique

Ionic liquid compressors are a new technology with great potential in hydrogen refueling stations, but there are two main problems during operation. First, the reciprocating oscillation of the liquid piston will cause some ionic liquid to be mixed into the hydrogen and lost with the exhaust gas. Second, when monitoring the working process in the cylinder, it was found that the current compression process has poor heat exchange effect, fails to achieve ideal isothermal compression, and the compression power consumption is relatively high.

Summary of the invention

In order to solve the problems existing in the prior art, the present invention proposes an ionic liquid compressor and a working method thereof for liquid replenishment cooling by controlling spray through piston displacement, and realizes efficient enhanced heat exchange and ionic liquid replenishment by controlling the spray behavior in a specific compression process.

An ionic liquid compressor for liquid replenishment cooling by controlling the displacement of a piston comprises a compressor body and a position detection unit, wherein a nozzle capable of spraying ionic liquid spray is provided at the top of a compression chamber of the compressor body, and the position detection unit is arranged on the compressor body and is used to detect the position of a free piston of the compressor body;

When the gas in the compression chamber is compressed, the nozzle can spray the ionic liquid spray into the compression chamber;

When the compression chamber is expanding, sucking in air, and exhausting air, the nozzle stops spraying the ionic liquid spray into the compression chamber.

Preferably, the position detection unit adopts a distance measuring unit, and the distance measuring unit is used to detect the position of the end of the free piston in real time.

Preferably, the distance measuring unit includes a reflector and a laser displacement sensor, the reflector is arranged on the free piston and the bottom surface of the free piston, the laser displacement sensor is arranged on the compressor body, and the laser emitted by the laser displacement sensor is vertically irradiated on the reflector.

Preferably, the compressor body also includes a cylinder and a hydraulic cylinder, the lower end of the cylinder is fixedly connected to the upper end of the hydraulic cylinder, the inner cavity of the cylinder is connected to the inner cavity of the hydraulic cylinder, the free piston is arranged in a cavity jointly formed by the inner cavity of the cylinder and the inner cavity of the hydraulic cylinder, the upper end of the free piston is arranged in the inner cavity of the cylinder, and the lower end of the free piston is arranged in the inner cavity of the hydraulic cylinder; the intake valve and the exhaust valve of the compressor body are both arranged at the upper end of the cylinder, and the nozzle is arranged at the upper end of the inner cavity of the cylinder.

Preferably, the position detection unit is arranged in the oil chamber of the hydraulic cylinder, and the position detection unit can detect the distance between the lower end surface of the free piston and the bottom of the inner chamber of the hydraulic cylinder.

Preferably, the hydraulic cylinder is provided with a hydraulic oil inlet and outlet, and a breathing hole is opened on the lower end of the cylinder, and the breathing hole is communicated with the inner cavity of the cylinder;

The upper and lower ends of the free piston are both provided with piston ring support ring assemblies. The upper end of the free piston is sealed with the inner cavity of the cylinder through the piston ring support ring assembly, and the lower end of the free piston is sealed with the inner cavity of the hydraulic cylinder through the piston ring support ring assembly.

Preferably, the outer wall of the cylinder is provided with heat exchange fins.

Preferably, the upper end of the cylinder has a cylinder end cover, and the cylinder end cover is provided with an intake passage, an exhaust passage and an ionic liquid passage, the intake passage, the exhaust passage and the ionic liquid passage are all connected to the cylinder cavity, and the nozzle is installed at the outlet end of the ionic liquid passage;

The intake valve and exhaust valve of the compressor body are respectively arranged on the intake passage and the exhaust passage, the intake valve is arranged at the inlet end of the intake passage, the outlet of the intake valve is communicated with the inlet end of the intake passage, the exhaust valve is arranged at the outlet end of the exhaust passage, the inlet of the exhaust valve is communicated with the outlet end of the exhaust passage, a pressure valve cover is connected to the cylinder end cover, an intake port and an exhaust port are arranged on the pressure valve cover, boss structures for respectively pressing the intake valve and the exhaust valve are arranged at the outlet end of the intake port and the inlet end of the exhaust port on the pressure valve cover, the outlet end of the intake port and the inlet end of the exhaust port are communicated with the inlet of the intake valve and the outlet of the exhaust valve respectively;

The air inlet valve and the exhaust valve are both one-way valves.

Preferably, it also includes a spray control unit and a liquid supply unit, the liquid supply unit is connected to the nozzle, the liquid supply unit is used to provide the nozzle with ionic liquid for spraying, and the position detection unit and the liquid supply unit are both connected to the spray control unit;

When the gas in the compression chamber is compressed, the spray control unit controls the liquid supply unit to supply liquid to the nozzle, and the nozzle sprays the ionic liquid spray into the compression chamber;

When the compression chamber is expanding, sucking in air, and exhausting air, the spray control unit controls the liquid supply unit to stop supplying liquid to the nozzle.

The working method of the ionic liquid compressor for liquid replenishment cooling by controlling the piston displacement spray of the present invention comprises an expansion process, an air intake process, a compression process and an exhaust process;

During the compression process, the air inlet valve and the air outlet valve of the compressor body are closed, and the ionic liquid spray is sprayed into the compression chamber through the nozzle, and the ionic liquid spray is used to cool the compression chamber and replenish the ionic liquid in the compression chamber;

During the exhaust process, the intake valve is closed, the exhaust valve is opened, and the nozzle stops spraying the ionic liquid spray into the compression chamber;

During the expansion process, the intake valve is closed, the exhaust valve is closed, and the nozzle stops spraying the ionic liquid spray into the compression chamber;

During the suction process, the intake valve opens, the exhaust valve closes, and the nozzle stops spraying the ionic liquid spray into the compression chamber.

The present invention has the following beneficial effects:

The ionic liquid compressor of the present invention, which controls the piston displacement to spray for liquid replenishment cooling, adds the nozzle and position detection unit on the basis of the existing ionic liquid compressor, uses the nozzle to spray the ionic liquid spray into the compression chamber to strengthen the heat exchange, and replenishes the ionic liquid lost in the compression chamber due to exhaust, and the spraying behavior is combined with the pressure and temperature rise characteristics in the compression chamber so that it is only carried out during the compression process, specifically by monitoring the piston position to determine the start and end of the process, so as to control the spraying. The position detection unit can detect the position of the free piston, and according to the position of the free piston, it can be determined whether the compressor body is in the expansion stage, the suction stage, the compression stage or the exhaust stage. In the expansion stage and the suction stage, the pressure and temperature in the compressor body are relatively low, so it is not necessary to spray cooling; in the exhaust stage of the compressor body, if the spraying is continued, the sprayed ionic liquid spray will flow away directly with the exhaust, resulting in unnecessary waste of ionic liquid, so it is necessary to control the nozzle to spray only during the gas compression process of the compressor body, and take away the heat generated during the gas pressurization process. In summary, the present invention solves the problem of the loss of liquid ionic liquid during the operation of the current ionic liquid compressor and the poor heat dissipation effect in the cylinder during the compression process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a cross-sectional structural diagram of an ionic liquid compressor of the present invention that controls piston displacement by spraying for liquid replenishment cooling.

FIG. 2 is a schematic diagram showing a typical position of a piston in a cylinder according to the present invention.

Figure 3 is a schematic diagram of the nozzle behavior corresponding to the bottom position of the piston in the hydraulic cylinder of the present invention, wherein (a) is a schematic diagram of the nozzle opening at the end of the intake process and the beginning of the compression process, (b) is a schematic diagram of the nozzle closing at the end of the compression process and the beginning of the exhaust process, (c) is a schematic diagram of the piston position during expansion and intake process being the same as the piston position in (b) but the nozzle remains closed, and (d) is a schematic diagram of the nozzle opening at the end of the intake process and the piston position being the same as the piston position in (a).

FIG. 4 is a schematic diagram of the nozzle motion control principle in an embodiment of the present invention.

In the figure: 11-pressure valve cover, 12-air inlet, 13-inlet valve, 14-exhaust port, 15-exhaust valve, 21-cylinder end cover, 22-inlet passage, 23-exhaust passage, 24-ionic liquid passage, 25-nozzle, 26-ionic liquid spray, 31-cylinder, 32-heat exchange fins, 33-ionic liquid, 34-breathing hole, 35-compression chamber, 41-free piston, 42-piston ring support ring assembly, 43-reflector, 51-hydraulic cylinder, 52-hydraulic oil, 53-hydraulic oil inlet and outlet, 54-laser displacement sensor, 55-sensor signal transmission passage.

Detailed ways

Hereinafter, the specific embodiments of the present application will be described in detail with reference to the accompanying drawings. According to these detailed descriptions, those skilled in the art can clearly understand the present application and can implement the present application. Without violating the principles of the present application, the features in the various embodiments can be combined to obtain new implementations, or certain features in certain embodiments can be replaced to obtain other preferred implementations.

Referring to FIG. 1 , the ionic liquid compressor of the present invention for controlling the displacement of the piston to spray for liquid replenishment cooling comprises a compressor body and a position detection unit. The top of the compression chamber 35 of the compressor body is provided with a nozzle 25 capable of spraying the ionic liquid spray. The position detection unit is provided on the compressor body and is used to detect the position of the free piston 41 of the compressor body. The position detection unit can detect the position of the free piston, and according to the position of the free piston, it can be determined whether the compressor body is in the expansion stage, the suction stage or the compression stage.

Referring to FIG. 3 , when the gas in the compression chamber 35 is compressed, the nozzle 25 can spray the ionic liquid spray 26 into the compression chamber. At this time, the ionic liquid spray 26 can take away the heat generated during the gas pressurization process, and at the same time, the ionic liquid is added to the compression chamber 35;

When expansion, suction and exhaust are carried out in the compression chamber 35, the nozzle 25 stops spraying the ionic liquid spray 26 into the compression chamber. During the expansion stage and the suction stage, the pressure and temperature in the compressor body are relatively low, so spray cooling is unnecessary. During exhaust, since the exhaust valve 15 of the compressor body will be opened, in order to prevent the ionic liquid spray from flowing away directly with the exhaust gas, causing unnecessary waste of the ionic liquid, the spraying should be stopped at this time.

1 to 4 , the working method of the ionic liquid compressor of the present invention for controlling the displacement of the piston to spray for liquid replenishment cooling includes an expansion process, an intake process, a compression process and an exhaust process;

During the compression process, the intake valve 13 and the exhaust valve 15 of the compressor body are both in a closed state, and the ionic liquid spray 26 is sprayed into the compression chamber through the nozzle 25, and the compression chamber is cooled by the ionic liquid spray 26. At the same time, the ionic liquid in the compression chamber 35 is replenished;

During the exhaust process, the intake valve 13 is closed, the exhaust valve 15 is opened, and the nozzle 25 stops spraying the ionic liquid spray 26 into the compression chamber;

During the expansion process, the inlet valve 13 is closed, the exhaust valve 15 is closed, and the nozzle 25 stops spraying the ionic liquid spray 26 into the compression chamber;

During the air intake process, the air inlet valve 13 is opened, the air outlet valve 15 is closed, and the nozzle 25 stops spraying the ionic liquid spray 26 into the compression chamber.

The present invention installs a laser displacement sensor at the bottom of the hydraulic cylinder to monitor the displacement of the free piston, and judges the working state in the cylinder by the piston position, so as to accurately control the nozzle action, so that the spray in the cylinder is only carried out in the gas compression stage, and the cylinder is replenished with liquid while efficiently enhancing heat exchange, which not only saves compression work but also avoids the waste of ionic liquid. It is an efficient and reliable liquid replenishment cooling method for ionic liquid compressors.

Referring to Figure 1, the position detection unit of the present invention adopts a distance measuring unit, which is used to detect the position of the end of the free piston 41 in real time. In this way, the position information of the end of the free piston 41 measured by the distance measuring unit can be used to determine whether the compressor body is in the expansion stage, the intake stage, the compression stage or the exhaust stage.

Referring to FIG. 1 , specifically, the distance measuring unit of the present invention comprises a reflector 43 and a laser displacement sensor 54. The reflector 43 is arranged on the lower end surface of the free piston 41, and the laser displacement sensor 54 is arranged at the lower end of the compressor body. The laser emitted by the laser displacement sensor 54 is vertically irradiated on the reflector 43. The specific position of the free piston 41 can be measured by the reflector 43 and the laser displacement sensor 54. After position calibration (i.e., the distance between the reflector 43 and the laser displacement sensor 54 is matched with the position of the free piston 41 when the compressor body is in the compression stage, exhaust stage, expansion stage and intake stage), it can be judged whether the compressor body is in the expansion stage, intake stage, compression stage or exhaust stage by the distance between the reflector 43 and the laser displacement sensor 54.

Referring to Figure 1, the compressor body of the present invention also includes a cylinder 31 and a hydraulic cylinder 51. The lower end of the cylinder 31 is fixedly connected to the upper end of the hydraulic cylinder 51, the inner cavity of the cylinder 31 is connected to the inner cavity of the hydraulic cylinder 51, and the free piston 41 is arranged in a cavity jointly formed by the inner cavity of the cylinder 31 and the inner cavity of the hydraulic cylinder 51. The upper end of the free piston 41 is arranged in the inner cavity of the cylinder 31, and the lower end of the free piston 41 is arranged in the inner cavity of the hydraulic cylinder 51; the intake valve 13 and the exhaust valve 15 of the compressor body are both arranged at the upper end of the cylinder 31, and the nozzle 25 is arranged at the upper end of the inner cavity of the cylinder 31. By injecting oil into and draining oil from the hydraulic cylinder 51, the up and down reciprocating motion of the free piston 41 can be controlled.

In the above-mentioned compressor body, the position detection unit adopts the above-mentioned distance measuring unit, and the reflector 43 is embedded in the lower end surface of the free piston 41, and the laser displacement sensor 54 is embedded in the bottom surface of the inner cavity of the hydraulic cylinder 51. The reflector 43 is directly opposite to the laser emitting end of the laser displacement sensor 54 and is perpendicular to the laser beam emitted by the laser displacement sensor 54. The distance between the lower end surface of the free piston 41 and the bottom surface of the inner cavity of the hydraulic cylinder 51 can be determined by the reflector 43 and the laser displacement sensor 54, see Figure 3. The hydraulic cylinder 51 of the present invention is provided with a hydraulic oil inlet and outlet 53, which can be arranged in the middle of the bottom of the hydraulic cylinder 51. The shape of the free piston 41 is similar to a dumbbell type. The upper and lower ends of the free piston 41 are both provided with a piston ring support ring assembly 42. The upper end of the free piston 41 is sealed with the inner cavity of the cylinder 31 through the piston ring support ring assembly 42, and the lower end of the free piston 41 is sealed with the inner cavity of the hydraulic cylinder 51 through the piston ring support ring assembly 42. A breathing hole 34 is opened on the lower end of the cylinder 31, and the breathing hole 34 is connected with the inner cavity of the cylinder 31. The breathing hole 34 can balance the annular cavity formed between the piston ring support ring assembly 42 at the upper and lower ends of the free piston 41 and the inner wall of the compressor body with the external atmospheric pressure, reduce the resistance of the free piston 41 when it moves back and forth, and prevent the gas in the annular cavity from being heated to cause the compressor body to deform, resulting in reduced sealing between the piston ring support ring assembly 42 and the cylinder 31 and between the piston ring support ring assembly 42 and the hydraulic cylinder 51.

The present invention also provides heat exchange fins 32 on the outer wall of the cylinder 31 to improve the heat exchange effect, quickly achieve cooling in the compression stage, and improve the compression efficiency.

The upper end of the cylinder 31 of the present invention has a cylinder end cover 21, and the cylinder end cover 21 is provided with an intake passage 22, an exhaust passage 23 and an ionic liquid passage 24, and the intake passage 22, the exhaust passage 23 and the ionic liquid passage 24 are all connected to the inner cavity of the cylinder 31, and the nozzle 25 is installed at the outlet end of the ionic liquid passage 24;

The intake valve 13 and the exhaust valve 15 of the compressor body are respectively arranged on the intake passage 22 and the exhaust passage 23, the intake valve 13 is arranged at the inlet end (upper end) of the intake passage 22, and the outlet of the intake valve 13 is connected to the inlet end of the intake passage 22, the exhaust valve 15 is arranged at the outlet end (upper end) of the exhaust passage 23, and the inlet of the exhaust valve 15 is connected to the outlet end of the exhaust passage 23, the cylinder end cover 21 is connected with the pressure valve cover 11, the pressure valve cover 11 is provided with an intake port 12 and an exhaust port 14, the pressure valve cover 11 is provided with a boss structure for respectively pressing the intake valve 13 and the exhaust valve 15 at the outlet end (lower end) of the intake port 12 and the inlet end (lower end) of the exhaust port 14, the outlet end (lower end) of the intake port 12 and the inlet end (lower end) of the exhaust port 14 are respectively connected with the inlet of the intake valve 13 and the outlet of the exhaust valve 15; the intake valve 13 and the exhaust valve 15 both adopt one-way valves.

In order to realize automatic control, the present invention may also be provided with a spray control unit, wherein a liquid supply unit for providing ionic liquid to the nozzle 25 is connected to the inlet end (upper end) of the ionic liquid passage 24, and the position detection unit and the liquid supply unit are both connected to the spray control unit; the spray control unit can determine whether the compressor is in the expansion stage, the intake stage, the compression stage or the exhaust stage through the position information of the free piston 41 obtained by the position detection unit; when the gas in the compression chamber 35 is compressed (that is, the compressor is in the compression stage), the spray control unit controls the liquid supply unit to supply liquid to the nozzle 25, and the nozzle 25 sprays the ionic liquid spray 26 into the compression chamber;

When the compression chamber 35 is expanding, sucking in air, and exhausting air, the spray control unit controls the liquid supply unit to stop supplying liquid to the nozzle 25 .

Example

1 is a cross-sectional structural diagram of the ionic liquid compressor of the present embodiment in which the piston displacement is controlled by spraying for liquid replenishment cooling. The ionic liquid compressor of the present embodiment in which the piston displacement is controlled by spraying for liquid replenishment cooling mainly comprises a pressure valve cover 11, a cylinder end cover 21, a cylinder 31, a free piston 41 and a hydraulic cylinder 51; the top of the cylinder 31 is connected to the cylinder end cover 21 by bolts, and the bottom of the cylinder 31 is connected to the hydraulic cylinder 51 by bolts; the pressure valve cover 11 is fixed to the top of the cylinder end cover 21 by bolts. The pressure valve cover 11 has an air inlet 12 and an exhaust port 14; the cylinder end cover 21 has an air inlet passage 22, an exhaust passage 23, and an ionic liquid passage 24; a nozzle 25 is provided in the middle of the bottom of the cylinder end cover 21 and is connected to the bottom of the ionic liquid passage 24; the nozzle 25 sprays an ionic liquid spray 26 into the cylinder 31; a heat exchange fin 32 is provided on the outer wall of the cylinder 31, and a breathing hole 34 is provided on the opposite side of the bottom of the cylinder 31; hydraulic oil 52 is provided inside the hydraulic cylinder 51, and a hydraulic oil inlet and outlet 53 is provided in the middle of the bottom of the hydraulic cylinder 51; a laser displacement sensor 5 is fixed on one side of the bottom of the hydraulic cylinder 51 4. A sensor signal transmission path 55 is provided below the laser displacement sensor 54; the lower part of the free piston 41 in the hydraulic cylinder 51 is filled with hydraulic oil 52, and the hydraulic oil 52 enters and exits the hydraulic cylinder 51 through the hydraulic oil inlet and outlet to control the up and down reciprocating motion of the free piston 41; the upper part of the free piston 41 in the cylinder 31 is covered with ionic liquid 33; the side of the upper part of the free piston 41 in contact with the cylinder 31 and the side of the lower part of the free piston 41 in contact with the hydraulic cylinder are both provided with piston ring support ring assemblies 42; a reflector 43 is installed at the bottom of the free piston 41 facing the laser displacement sensor 54.

FIG2 shows several typical positions of the free piston 41 in the cylinder in this embodiment. As shown in FIG2, the free piston 41 reciprocates up and down in the cylinder 31. Low-pressure gas with a pressure of _P1 is sucked in through the intake valve 13, and high-pressure gas with a pressure of _P2 is discharged through the exhaust valve 15. Position A is the bottom dead center of the upper end of the free piston 41, and position B is the top dead center of the upper end of the free piston 41. When the free piston 41 moves to position C, the compression process ends and the exhaust process begins, and the exhaust valve 15 opens to start exhausting.

The displacement of the free piston 41 from position A to position B is the piston stroke S ₂ , and the displacement of the free piston 41 from position A to position C is S ₁ . Assuming n is a polytropic process index, then:

So _S1 is:

Fig. 3 is a schematic diagram of the nozzle behavior corresponding to the bottom position of the piston in the hydraulic cylinder of the present invention. When the free piston 41 is at the bottom dead center A (see (a)), at this time in the hydraulic cylinder 51, the distance between the bottom of the free piston 41 and the bottom of the hydraulic oil level is S ₀ , and the laser displacement sensor 54 is used to calibrate this position; when the free piston 41 is at position C (see (b)), the distance between the bottom of the free piston 41 and the bottom of the hydraulic oil level is S ₀ +S ₁ , and the laser displacement sensor 54 is used to calibrate this position.

Combined with the control principle diagram of the nozzle action shown in Figure 4. When the free piston 41 reaches position A in the hydraulic cylinder 51, it is considered that the free piston 41 has reached the bottom dead center, the suction process is over, the free piston 41 is about to start moving upward, and the compression process is about to start. At this time, the laser displacement sensor 54 transmits the displacement signal _S0 to the spray control unit. After receiving the displacement signal, the spray control unit interprets it as a control command, controls the nozzle 25 to open, and sprays the ionic liquid spray 26 into the cylinder 31;

When the free piston 41 moves upward to the C position, it is considered that the compression process ends and the exhaust process begins. At this time, the laser displacement sensor 54 transmits the displacement signal S ₀ +S ₁ to the spray control unit. After receiving the displacement signal, the spray control unit interprets it as a control command and controls the nozzle 25 to close.

When the free piston 41 reaches the top dead center B and starts to move downward again, it will still pass through position C. At this time, the laser displacement sensor 54 still obtains the displacement signal S ₀ +S ₁ . After the laser displacement sensor 54 transmits the signal to the spray control unit, the spray control unit will still interpret the signal as a "nozzle closing" control command. However, since the nozzle 25 itself is already in a closed state at this time, the nozzle 25 does not change its working state at this time.

When the free piston 41 continues to move downward to position A, it is considered that the free piston 41 has reached the bottom dead center, the intake process is over, the free piston 41 is about to start moving upward, and the compression process is about to begin. At this time, the laser displacement sensor 54 transmits the received displacement signal _S0 to the spray control unit, and the spray control unit parses the signal and controls the nozzle 25 to open. At this time, the nozzle 25 opens and sprays the ionic liquid spray 26 into the cylinder 31.

In summary, the ionic liquid compressor of the present invention that controls the piston displacement to perform liquid replenishment and cooling monitors the displacement of the free piston through the laser displacement sensor at the bottom, and judges the working state in the cylinder through the position of the free piston in the cylinder, thereby controlling the opening and closing of the nozzle on the top of the cylinder, so that the spray is accurately controlled in the link of gas compression, which can not only efficiently dissipate the heat of the high-temperature gas in the compression and reduce the loss of compression work, but also effectively prevent the injected ionic liquid from flowing away directly with the exhaust gas, thereby reducing the waste of ionic liquid. It is an accurate and efficient way to replenish the liquid in the cylinder of the ionic liquid compressor and cool the compressed gas.

Claims (10)

1. An ionic liquid compressor for liquid replenishment cooling by controlling the displacement of a piston, characterized in that it comprises a compressor body and a position detection unit, wherein a nozzle (25) capable of spraying ionic liquid spray is provided at the top of a compression chamber (35) of the compressor body, and the position detection unit is arranged on the compressor body and is used to detect the position of a free piston (41) of the compressor body; When the gas in the compression chamber (35) is compressed, the nozzle (25) can spray the ionic liquid spray (26) into the compression chamber; When the compression chamber (35) is expanding, inhaling, and exhausting, the nozzle (25) stops spraying the ionic liquid spray (26) into the compression chamber. 2. The ionic liquid compressor for rehydration cooling by piston displacement controlled spray according to claim 1 is characterized in that the position detection unit adopts a distance measuring unit, and the distance measuring unit is used to detect the position of the end of the free piston (41) in real time. 3. The ionic liquid compressor for rehydration cooling by piston displacement controlled spray according to claim 2 is characterized in that the distance measuring unit includes a reflector (43) and a laser displacement sensor (54), the reflector (43) is arranged on the bottom surface of the free piston (41), the laser displacement sensor (54) is arranged on the compressor body, and the laser emitted by the laser displacement sensor (54) is vertically irradiated on the reflector (43). 4. The ionic liquid compressor for rehydration cooling by piston displacement controlled spraying according to claim 1 is characterized in that the compressor body further comprises a cylinder (31) and a hydraulic cylinder (51), the lower end of the cylinder (31) is fixedly connected to the upper end of the hydraulic cylinder (51), the inner cavity of the cylinder (31) is communicated with the inner cavity of the hydraulic cylinder (51), the free piston (41) is arranged in a cavity jointly formed by the inner cavity of the cylinder (31) and the inner cavity of the hydraulic cylinder (51), the upper end of the free piston (41) is arranged in the inner cavity of the cylinder (31), and the lower end of the free piston (41) is arranged in the inner cavity of the hydraulic cylinder (51); the intake valve (13) and the exhaust valve (15) of the compressor body are both arranged at the upper end of the cylinder (31), and the nozzle (25) is arranged at the upper end of the inner cavity of the cylinder (31). 5. The ionic liquid compressor for rehydration cooling by piston displacement controlled spray according to claim 4 is characterized in that a position detection unit is arranged in the oil chamber of the hydraulic cylinder (51), and the position detection unit can detect the distance between the lower end surface of the free piston (41) and the bottom of the inner chamber of the hydraulic cylinder (51). 6. The ionic liquid compressor for liquid replenishment cooling by controlling the piston displacement spray according to claim 4, characterized in that a hydraulic oil inlet and outlet (53) is provided on the hydraulic cylinder (51), a breathing hole (34) is provided on the lower end of the cylinder (31), and the breathing hole (34) is communicated with the inner cavity of the cylinder (31); The upper and lower ends of the free piston (41) are both provided with a piston ring support ring assembly (42); the upper end of the free piston (41) is sealed with the inner cavity of the cylinder (31) through the piston ring support ring assembly (42); and the lower end of the free piston (41) is sealed with the inner cavity of the hydraulic cylinder (51) through the piston ring support ring assembly (42). 7. The ionic liquid compressor with piston displacement controlled spray for liquid replenishment cooling according to claim 4, characterized in that the outer wall of the cylinder (31) is provided with heat exchange fins (32). 8. The ionic liquid compressor for liquid replenishment cooling by piston displacement controlled spraying according to claim 4, characterized in that the upper end of the cylinder (31) is provided with a cylinder end cover (21), the cylinder end cover (21) is provided with an intake passage (22), an exhaust passage (23) and an ionic liquid passage (24), the intake passage (22), the exhaust passage (23) and the ionic liquid passage (24) are all connected to the inner cavity of the cylinder (31), and the nozzle (25) is installed at the outlet end of the ionic liquid passage (24); The intake valve (13) and the exhaust valve (15) of the compressor body are respectively arranged on the intake passage (22) and the exhaust passage (23); the intake valve (13) is arranged at the inlet end of the intake passage (22); the outlet of the intake valve (13) is communicated with the inlet end of the intake passage (22); the exhaust valve (15) is arranged at the outlet end of the exhaust passage (23); the inlet of the exhaust valve (15) is communicated with the outlet end of the exhaust passage (23); the cylinder end cover (21 ) is connected to a pressure valve cover (11), the pressure valve cover (11) is provided with an air inlet (12) and an air outlet (14), the pressure valve cover (11) is provided with a boss structure for respectively pressing the air inlet valve (13) and the air outlet (15) at the outlet end of the air inlet (12) and the inlet end of the air outlet (14), the outlet end of the air inlet (12) and the inlet end of the air outlet (14) are respectively connected to the inlet of the air inlet valve (13) and the outlet of the air outlet (15); The air intake valve (13) and the air exhaust valve (15) are both one-way valves. 9. The ionic liquid compressor for liquid replenishment cooling by piston displacement controlled spraying according to claim 1, characterized in that it also comprises a spray control unit and a liquid supply unit, the liquid supply unit is connected to the nozzle (25), the liquid supply unit is used to provide the ionic liquid for spraying to the nozzle (25), and the position detection unit and the liquid supply unit are both connected to the spray control unit; When the gas in the compression chamber (35) is compressed, the spray control unit controls the liquid supply unit to supply liquid to the nozzle (25), and the nozzle (25) sprays the ionic liquid spray (26) into the compression chamber; When expansion, air intake and exhaust are performed in the compression chamber (35), the spray control unit controls the liquid supply unit to stop supplying liquid to the nozzle (25). 10. The working method of the ionic liquid compressor for liquid replenishment cooling by controlling the piston displacement spray according to any one of claims 1 to 9, characterized in that it includes an expansion process, an intake process, a compression process and an exhaust process; During the compression process, the air inlet valve (13) and the air outlet valve (15) of the compressor body are both closed, and the ionic liquid spray (26) is sprayed into the compression chamber through the nozzle (25), and the compression chamber is cooled by the ionic liquid spray (26), and the ionic liquid in the compression chamber (35) is replenished at the same time; During the exhaust process, the intake valve (13) is closed, the exhaust valve (15) is opened, and the nozzle (25) stops spraying the ionic liquid spray (26) into the compression chamber; During the expansion process, the inlet valve (13) is closed, the exhaust valve (15) is closed, and the nozzle (25) stops spraying the ionic liquid spray (26) into the compression chamber; During the air intake process, the air intake valve (13) is opened, the air exhaust valve (15) is closed, and the nozzle (25) stops spraying the ionic liquid spray (26) into the compression chamber.