Micro free piston power device with adjustable compression ratio

Abstract

The compression-ratio-adjustable micro-free piston power device comprises an air cylinder body, a partition plate is arranged in the air cylinder body, and the interior of the air cylinder body is divided into two spaces by the partition plate; a springback chamber fixed piston is arranged in the space on one side; a springback chamber is arranged between the springback chamber fixing piston and the partition plate on the same side; and the pressure in the rebound chamber is adjustable. A combustion chamber fixing piston is arranged in the space on the other side; a combustion chamber is arranged between the combustion chamber fixing piston and the same-side partition plate; an air inlet pipe and an exhaust pipe are arranged on the air cylinder body where the combustion chamber is located in a staggered mode, and the exhaust pipe is closer to the partition than the air inlet pipe; the distance between the combustion chamber fixing piston and the rebound chamber fixing piston is adjusted, the stroke of the air cylinder body is changed, and then the compression ratio formed between the combustion chamber and the combustion chamber fixing piston is adjusted. According to the miniature free piston power device, the functions of starting, stable operation and stable shutdown of the miniature free piston power device can be achieved by optimizing the structure.

Description

Technical Field

[0001] The invention relates to a novel power device utilizing micro-free piston compression ignition and power conversion, in particular to a micro-free piston power device with adjustable compression ratio. Background Art

[0002] In order to further improve energy efficiency, researchers from various countries are developing new energy conversion power devices. Among them, free piston power devices, compared with traditional engines, have the advantages of simple structure, high energy density, and wide fuel applicability because they do not require a crank-connecting rod mechanism. They have become one of the typical new energy conversion devices. When the device is running, the free piston compresses the homogeneous gas. After the combustible gas is compressed and ignited, it pushes the piston to run in the opposite direction, so that the free piston continues to reciprocate. It has great application prospects.

[0003] In recent years, with the advancement of precision machining technology and the rapid development of control technology, micro-machines and micro-intelligent electronic products have been rapidly developed and widely used, such as small civilian drones, small robots, wearable electronic devices, portable measurement equipment in engineering operations, biomedical devices, single-soldier combat mobile equipment in the military field, micro-bionic reconnaissance aircraft, micro-missiles, etc. Among them, portable, fast-charging and long-endurance power sources have become one of the important factors influencing the development of micro-electromechanical systems. Compared with other types of heat engines, free piston power devices eliminate rotating parts such as crankshafts and connecting rods, so the piston can move freely, so the compression ratio can be freely adjusted, the fuel is widely applicable, and the structure is simple, which is more suitable for miniaturization. However, the research results show that methane gas is compressed and ignited in a small space, and the compression ratio needs to reach about 48, so a large compression starting thrust is required. Secondly, the homogeneous compression combustion method has the advantages of high thermal efficiency and low emissions, but it also has problems such as difficult fire control. Due to the lack of spark plug ignition and timed fuel injection devices, the ignition position is variable. If the ignition time is advanced, it will cause rough combustion or even explosion; if the ignition time is delayed, it will cause afterburning and misfire. Therefore, it is necessary to optimize the structure of the micro free piston power device to achieve the start-up, stable operation and smooth shutdown functions of the micro free piston power device. Summary of the invention

[0004] In order to solve the deficiencies in the prior art, the present application proposes a micro free piston power device with an adjustable compression ratio, optimizes the design of the cylinder body and piston assembly of the existing micro free piston power device, uses the piston assembly as a fixed part and the cylinder body as a movable part; it can realize the starting, stable operation and smooth shutdown functions of the micro free piston power device.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A micro-free piston power device with an adjustable compression ratio, comprising:

[0007] Cylinder block;

[0008] A partition is provided inside the cylinder body, and the partition separates the inside of the cylinder body into two spaces;

[0009] A rebound chamber fixing piston is arranged in one side space;

[0010] The rebound chamber is located between the fixed piston and the partition on the same side; the pressure in the rebound chamber is adjustable;

[0011] A combustion chamber fixed piston is arranged in the space on the other side;

[0012] Combustion chamberThe combustion chamber is between the fixed piston and the partition on the same side;

[0013] The intake pipe and the exhaust pipe are staggered on the cylinder block where the combustion chamber is located, and the exhaust pipe is closer to the partition than the intake pipe;

[0014] The distance between the fixed piston of the combustion chamber and the fixed piston of the rebound chamber is adjusted to change the stroke of the cylinder body, thereby adjusting the compression ratio formed between the combustion chamber and the fixed piston of the combustion chamber.

[0015] Furthermore, during operation, the positions of the rebound chamber fixed piston and the combustion chamber fixed piston are fixed, and the cylinder body reciprocates between the rebound chamber fixed piston and the combustion chamber fixed piston.

[0016] Furthermore, the cylinder body is cylindrical.

[0017] Furthermore, the rebound chamber is connected to the supercharger through a high-pressure air pipe.

[0018] Furthermore, a pin switch is arranged outside the cylinder body at the side where the rebound chamber is located, and the cylinder body is fixed by the pin switch.

[0019] Furthermore, the combustion chamber fixed piston is equipped with a position adjustment unit, and the distance between the combustion chamber fixed piston and the rebound chamber fixed piston is adjusted by the position adjustment unit.

[0020] Furthermore, the position adjustment unit adopts a gear rack mechanism, one of the gears or racks is fixedly connected to the combustion chamber fixed piston, and through the meshing transmission between the gear and the rack, the rotation of the gear is converted into axial movement of the combustion chamber fixed piston along the cylinder body.

[0021] Beneficial effects of the present invention:

[0022] The cylinder body and piston assembly of the existing micro-free piston power device are optimized, and the rebound chamber is used to replace the recovery structure. The pressure of the rebound chamber is adjusted by the supercharger to realize the starting process of the power device.

[0023] The free movement of the cylinder body is used to replace the free movement of the piston to complete the mixed gas compression and ignition process, thereby realizing the reciprocating operation of the micro power device;

[0024] By adjusting the rotation of the gear, the position of the piston relative to the bottom of the combustion chamber is changed, thereby realizing the adjustment function of the compression ratio of the micro-power device. At the same time, combined with the adjustment of the rebound chamber pressure, the start-up, stable operation and shutdown functions of the micro-power device are realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a two-dimensional cross-sectional schematic diagram of the device of the present invention.

[0026] Figures 2 to 8 It is a cyclic working process from the compression ignition of the gas to the completion of scavenging in the micro free piston power device according to the present invention;

[0027] In the figure: 1. supercharger, 2. high-pressure air pipe, 3. rebound chamber fixed piston, 4. rebound chamber, 5. intake pipe, 6. combustion chamber, 7. pin switch, 8. partition, 9. exhaust pipe, 10. combustion chamber fixed piston, 11. gear rack mechanism, 12. cylinder block. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] Combined with Figure 1 As shown, the present invention designs a compression ratio adjustable micro-free piston power device, including a cylinder body 12, the cylinder body 12 is cylindrical, and a partition 8 is fixedly installed in the middle position of the cylinder body 12, and the partition 8 separates the inside of the cylinder body 12 into two spaces, left and right. A rebound chamber fixed piston 3 is installed in the left space of the cylinder body 12, and the end surface of the rebound chamber fixed piston 3 and the end surface of the partition 8 on the same side are the rebound chamber 4. The rebound chamber 4 is connected to the supercharger 1 through the high-pressure air pipe 2, and the supercharger 1 pumps gas into the rebound chamber 4 through the high-pressure air pipe 2 to apply pressure to the rebound chamber 4.

[0030] A combustion chamber fixed piston 10 is installed in the right space of the cylinder body 12, and the combustion chamber 6 is formed between the end surface of the combustion chamber fixed piston 10 and the end surface of the partition plate 8 on the same side. An intake pipe 5 and an exhaust pipe 9 are arranged on the cylinder body 12 where the combustion chamber 6 is located. The intake pipe 5 and the exhaust pipe 9 are arranged at a certain distance, and the exhaust pipe 9 is closer to the partition plate 8 than the intake pipe 5. The combustible mixed gas is input into the combustion chamber 6 through the intake pipe 5, and the combustion exhaust gas in the combustion chamber 6 is discharged through the intake pipe 5.

[0031] During operation, the positions of the rebound chamber fixed piston 3 and the combustion chamber fixed piston 10 are fixed, and the cylinder body 12 reciprocates between the rebound chamber fixed piston 3 and the combustion chamber fixed piston 10 .

[0032] More preferably, a pin switch 7 is provided outside the cylinder body 12 on the side where the rebound chamber 4 is located, and the cylinder body 12 is fixed by the pin switch 7 so that it cannot move, and when the cylinder body 12 is locked, the size of the rebound chamber 4 is the initial space.

[0033] More preferably, the combustion chamber fixed piston 10 is equipped with a position adjustment unit, which uses the position adjustment unit to adjust the distance between the combustion chamber fixed piston 10 and the rebound chamber fixed piston 3, change the stroke of the cylinder body 12, and then adjust the compression ratio formed between the combustion chamber 6 and the combustion chamber fixed piston 10.

[0034] More preferably, the position adjustment unit includes a gear rack mechanism 11, wherein one of the gear or the rack is fixedly connected to the combustion chamber fixed piston 10, and the rotation of the gear is converted into the axial movement of the combustion chamber fixed piston 10 along the cylinder body 12 through the meshing transmission between the gear and the rack. In addition to the gear rack mechanism 11, the position adjustment unit can also be in other forms as long as it can drive the combustion chamber fixed piston 10 to move axially along the cylinder body 12.

[0035] More preferably, one end of the high-pressure air pipe 2 passes through the rebound chamber fixed piston 3 and extends into the combustion chamber 6, and the other end is connected to the supercharger 1. In addition, under the condition of meeting the airtightness, one end of the high-pressure air pipe 2 can extend into the combustion chamber 6 from the outer wall of the cylinder body 12. The working process of the device is described in detail below with reference to the accompanying drawings.

[0036] Based on the structural description of the above-mentioned compression ratio adjustable micro-free piston power device, the single cycle working process of the power device is introduced as follows:

[0037] Figures 2 to 8 This is the single cycle working process of the micro free piston power device. Figure 2 It can be seen that the pin switch 7 fixes the relative initial position of the cylinder body 12 and the rebound chamber fixed piston 3, forming the initial space of the rebound chamber 4, and the supercharger 1 inputs high-pressure gas to the rebound chamber 4 through the high-pressure gas pipe 2; at the same time, the combustible mixture enters the combustion chamber 6 through the intake pipe 5 in the initial state, and the intake process begins.

[0038] Figure 3 When the pressure in the rebound chamber 4 reaches the set value, the pin switch 7 is toggled, and the gas pressure in the rebound chamber 4 pushes the cylinder body 12 to move to the right.

[0039] Figure 4When the cylinder body 12 moves to the right to a certain position, the combustion chamber fixed piston 10 blocks the intake pipe 5 and the exhaust pipe 9, and the intake process ends at this time.

[0040] Figure 5 Under the action of the pressure in the rebound chamber 4, the cylinder body 12 continues to move to the right, and the relative space between the bottom of the combustion chamber 6 and the fixed piston 10 of the combustion chamber becomes smaller and smaller. During the compression process, the pressure and temperature of the combustible mixture gas gradually increase. When the compression ratio reaches a certain value, the temperature of the mixture gas rises to the ignition point temperature, and the mixture gas is compressed and ignited.

[0041] Figure 6 The mixed gas in the middle combustion chamber 6 ignites and burns, and the pressure rises sharply. When the gas pressure in the combustion chamber 6 is greater than the gas pressure in the rebound chamber 4, the cylinder body 12 starts to move to the left under the action of the pressure difference.

[0042] Figure 7 When the cylinder body 12 moves to a certain position, the exhaust pipe 9 opens first, and the combustion exhaust gas begins to be exhausted to the outside of the cylinder.

[0043] Figure 8 As the cylinder body 12 continues to move to the left, the relative space between the combustion chamber 6 and the combustion chamber fixed piston 10 becomes larger and larger until the intake pipe 5 opens and the fresh combustible mixture enters the combustion chamber 6, starting the ventilation process. At this point, the single compression ignition process is completed. The cylinder body continues to move in a reciprocating cycle under the pressure changes in the rebound chamber 4 and the combustion chamber 6.

[0044] Power unit startup, stable operation and shutdown control:

[0045] When the pressure in the rebound chamber 4 is too small, the distance that the cylinder body 12 moves to the right will become shorter, and the compression ratio formed by the combustion chamber 6 and the combustion chamber fixed piston 10 will be relatively low, and the mixed gas cannot be compressed and ignited. The gas delivery pressure in the supercharger 1 can be adjusted to increase the starting thrust of the power unit and further compress the combustible mixed gas until it is compressed and ignited, thereby completing the cold start process.

[0046] When the mixed gas in the combustion chamber 6 is compressed and burned, the rate of change of the mixed gas pressure value is large, causing the cylinder body 12 to run too fast to the left, affecting the ventilation process of the micro-power device. Therefore, the relative position of the combustion chamber fixed piston 10 can be adjusted through the gear rack mechanism 11. By rotating the gear rack mechanism 11 counterclockwise, the combustion chamber fixed piston 10 will move to the right, thereby extending the ventilation process and adjusting the compression ratio until the micro-power device can stably reciprocate.

[0047] By continuously rotating the rack and pinion mechanism 11 counterclockwise, the space formed by the combustion chamber fixed piston 10 and the combustion chamber 6 becomes larger and larger, so as to reduce the compression ratio of the combustible gas in the combustion chamber 6, making it impossible for the mixed gas to be compressed and ignited, and at the same time reduce the pressure of the gas in the rebound chamber 4, pushing the cylinder body 12 to move a smaller and smaller distance, thereby realizing the shutdown function of the micro power device.

[0048] The above embodiments are only used to illustrate the design ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design ideas disclosed by the present invention are within the protection scope of the present invention.

Claims

1. A micro-free piston power device with adjustable compression ratio, characterized in that: include: Cylinder block (12); A partition (8) is arranged in the cylinder body (12), and the partition (8) separates the inside of the cylinder body (12) into two spaces; A rebound chamber fixing piston (3) is arranged in the space on one side; The rebound chamber (4) is located between the fixed piston (3) of the rebound chamber and the partition plate (8) on the same side; the pressure in the rebound chamber (4) is adjustable; A combustion chamber fixed piston (10) is arranged in the space on the other side; A combustion chamber (6) is located between the combustion chamber fixed piston (10) and the baffle plate (8) on the same side; An intake pipe (5) and an exhaust pipe (9) are staggeredly arranged on a cylinder block (12) where a combustion chamber (6) is located, and the exhaust pipe (9) is closer to the partition plate (8) than the intake pipe (5); The distance between the combustion chamber fixed piston 10 and the rebound chamber fixed piston (3) is adjusted to change the stroke of the cylinder body (12), thereby adjusting the compression ratio formed between the combustion chamber (6) and the combustion chamber fixed piston (10).

2. A micro-free piston power device with adjustable compression ratio according to claim 1, characterized in that: During operation, the positions of the rebound chamber fixed piston (3) and the combustion chamber fixed piston (10) are fixed, and the cylinder body (12) reciprocates between the rebound chamber fixed piston (3) and the combustion chamber fixed piston (10).

3. The micro-free piston power device with adjustable compression ratio according to claim 1 is characterized in that: The cylinder body (12) is cylindrical.

4. The micro-free piston power device with adjustable compression ratio according to claim 1 is characterized in that: The rebound chamber (4) is connected to the supercharger (1) via a high-pressure air pipe (2).

5. The micro-free piston power device with adjustable compression ratio according to claim 1 is characterized in that: A pin switch (7) is arranged outside the cylinder body (12) on the side where the rebound chamber (4) is located, and the cylinder body (12) is fixed by using the pin switch (7).

6. The micro-free piston power device with adjustable compression ratio according to claim 1 is characterized in that: The combustion chamber fixed piston (10) is provided with a position adjustment unit, and the distance between the combustion chamber fixed piston (10) and the rebound chamber fixed piston (3) is adjusted by using the position adjustment unit.

7. The micro-free piston power device with adjustable compression ratio according to claim 1 is characterized in that: The position adjustment unit adopts a gear rack mechanism (11), wherein one of the gear or the rack is fixedly connected to the combustion chamber fixed piston (10), and the rotation of the gear is converted into the axial movement of the combustion chamber fixed piston (10) along the cylinder body (12) through the meshing transmission between the gear and the rack.

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