CN106545432B

CN106545432B - Half-dry and half-wet water cooling system for combined combustion chamber of two-stroke aviation heavy oil piston engine

Info

Publication number: CN106545432B
Application number: CN201610911054.2A
Authority: CN
Inventors: 周煜; 杜发荣; 孙鑫鑫; 徐征
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2016-10-19
Filing date: 2016-10-19
Publication date: 2021-02-05
Anticipated expiration: 2036-10-19
Also published as: CN106545432A

Abstract

The invention discloses a half-dry half-wet water cooling system for a combined combustion chamber of a two-stroke aviation heavy oil piston engine. The lower part of the cylinder body is also provided with two air inlet channels and an air outlet channel; the air outlet ends of the two air inlet channels are respectively communicated with two air inlets designed on the wall surface of the middle section of the cylinder sleeve; the air inlet end of the exhaust passage is communicated with an exhaust port designed on the wall surface of the middle section of the cylinder sleeve. The cooling system adopts a dry-wet combined structure, takes cooling capacity and system rigidity into consideration, improves the reliability of the system, adopts water cooling as a cooling mode, can meet the use requirements of high mechanical load and friction strength of the two-stroke engine, and has good applicability to the two-stroke engine.

Description

Half-dry and half-wet water cooling system for combined combustion chamber of two-stroke aviation heavy oil piston engine

Technical Field

The invention relates to a cooling system of an engine, in particular to a semi-dry semi-wet water cooling system for a combined combustion chamber of a two-stroke aviation heavy oil piston engine.

Background

With the continuous development of engine technology, the working environment of the engine is more and more specific and complex, the cooling performance of the engine becomes an important factor for ensuring the reliability of the engine, and the requirement on a cooling system is higher and higher when the engine is designed.

The cooling system is an important component of the engine and has the function of ensuring that the engine works in the optimum temperature state, and the engine cooling mode comprises water cooling and air cooling, wherein the water cooling refers to a series of devices which take away heat of high-temperature parts by using cooling liquid as a cooling medium and then radiate the heat to the atmosphere in a certain mode so as to reduce the temperature of the engine for cooling. The cooling device has the advantages of strong cooling capacity, compact arrangement, low noise, convenient use and the like. The air cooling does not perform liquid circulation in the engine, but performs heat dissipation on the cylinder through the aluminum sheet attached to the surface of the engine cylinder body, and has the advantages of simple structure, light weight, less faults, simple and convenient maintenance, strong adaptability to geographical environment and climate environment, short warm-up time after cold start and the like. The two-stroke aviation heavy oil piston engine has high mechanical load, high friction degree and high requirement on cooling capacity, and although the air cooling system has a simple structure, the two-stroke aviation heavy oil piston engine has insufficient cooling capacity, uneven cooling and large working noise at low speed and does not meet the aviation requirement, so the two-stroke aviation heavy oil piston engine is suitable for adopting a water cooling mode.

The matching form of the water-cooled engine cylinder body and the cylinder sleeve is divided into a dry type and a wet type. The dry cylinder sleeve is characterized in that the outer surface of the dry cylinder sleeve is not directly contacted with cooling water, and the wall thickness of the dry cylinder sleeve is generally 1-3 mm. In order to obtain a sufficient actual contact area with the cylinder body and ensure the heat dissipation and positioning of the cylinder sleeve, the machining precision of the outer surface of the cylinder sleeve and the inner surface of a cylinder body supporting hole matched with the cylinder sleeve is high, and the outer surface of the cylinder sleeve and the inner surface of the cylinder body supporting hole are generally in interference fit; the wet cylinder sleeve is in direct contact with cooling water, and the wall thickness is generally 5-9 mm. The outer surface of the cylinder liner is provided with two convex circular ring belts which ensure radial positioning and are respectively called an upper supporting positioning belt and a lower supporting sealing belt. The axial location of the cylinder liner is by means of an upper end flange. Compared with a dry cylinder sleeve, the wet cylinder sleeve is provided with the closed water jacket on the cylinder body, so that the cylinder sleeve is convenient to cast, easy to detach and replace and better in cooling effect, but only the top and the bottom of the cylinder sleeve are in contact with the cylinder body, and therefore the supporting rigidity of the cylinder sleeve is poor.

The two-stroke aviation heavy oil piston engine is in a working environment with high mechanical compliance and high friction strength for a long time, the engine needs a good cooling effect and high system rigidity during working, and a pure dry cylinder sleeve or a pure wet cylinder sleeve cannot meet the use requirement. In addition, the requirement for the cooling capacity of the fire surface of the combined combustion chamber based on the screw-in cylinder head is high, and the traditional cooling form and cooling method cannot meet the requirement.

Disclosure of Invention

Aiming at the problems, the invention provides a semi-dry semi-wet water cooling system for a combined combustion chamber of a two-stroke aviation heavy oil piston engine, which has the characteristic of good heat dissipation performance while being suitable for high mechanical load, improves the rigidity of the system, enhances the reliability and can meet the severe and complex working environment of the two-stroke aviation heavy oil piston engine.

The utility model provides a half dry half wet-type cooling system towards two-stroke aviation heavy oil piston engine organism which characterized in that: the cooling water flow channel is arranged on the cylinder body and the cylinder head of the single-cylinder piston engine cylinder, and the mode is as follows:

a cooling water inlet cavity and a cooling water outlet cavity are respectively designed at the upper and lower positions of the inner wall of the cylinder body; and the cooling water inlet cavity is communicated with the cooling water outlet cavity through a cooling water flow channel designed on the inner wall of the cylinder body, and the cooling water inlet cavity and the cooling water outlet cavity form a cooling water flow channel in the cylinder body together. The lower part of the cylinder body is provided with a cooling water inlet joint which is communicated with a cooling water inlet cavity; and the injection of cooling water in the cooling water flow channel is realized through a water inlet system.

The cylinder head is internally designed with a cylinder head internal cooling water flow passage which is communicated with the cylinder head internal cooling water flow passage through a water hole at the bottom of the cylinder head. The water holes are arranged on water outlet hole positions which are uniformly distributed on the circumference of the bottom of the cylinder head, and 4 water holes are arranged on each water outlet hole position along the radial direction of the cylinder head. A cooling liquid water outlet joint is arranged on the side wall of the top of the cylinder head and is communicated with a cooling water channel in the cylinder head; and the discharge of cooling water in the cooling water flow channel is realized through the water outlet system.

The invention has the advantages that:

1. the semi-dry semi-wet water cooling system improves the system rigidity while ensuring the cooling capacity of the system;

2. the semi-dry semi-wet water cooling system has the advantages that the air inlet and exhaust passages and the cooling water channel are in mixed layout, the structure is compact, the water tightness of the air inlet passage and the air exhaust passage is guaranteed by adopting dry interference fit of the cylinder body and the cylinder sleeve, the air inlet and exhaust passages of the cylinder body are effectively isolated from the cooling water channel in the cylinder body, the structure compactness is improved, and the weight is reduced;

3. the semi-dry and semi-wet type water cooling system adopts a dry-wet combined structural form, effectively improves the reliability of the system while ensuring the cooling capacity, and is favorable for promoting the temperature field balance of the system.

4. According to the semi-dry semi-wet water cooling system, the middle part of the cylinder head is provided with the cooling water flow channel, 4 water outlet hole sites are uniformly distributed on the periphery of the bottom, and each water outlet hole site is cast with 4 water holes along the radial direction of the cylinder head and is respectively communicated with the cooling water flow channels in the four cylinder bodies on the cylinder body, so that the cylinder head, particularly the fire surface of the cylinder head, can be effectively cooled.

Drawings

FIG. 1 is a schematic view of a water inlet system of the semi-dry semi-wet water cooling system according to the present invention;

FIG. 2 is a schematic view of the water outlet system of the semi-dry semi-wet water cooling system of the present invention

FIG. 3 is a sectional view of a cylinder of a single cylinder piston engine in the semi-dry semi-wet water cooling system of the present invention;

FIG. 4 is a schematic view of the cooling water flow passage in the cylinder body of the cylinder of the single-cylinder piston engine in the semi-dry semi-wet water cooling system according to the present invention;

FIG. 5 is a schematic diagram of the positions of the air inlet and outlet pipes of the cylinder of the single-cylinder piston engine in the semi-dry semi-wet water cooling system according to the present invention;

FIG. 6 is a schematic view of the structure of the intake and exhaust pipes of the cylinder of the single-cylinder piston engine in the semi-dry semi-wet water cooling system according to the present invention;

FIG. 7 is a schematic diagram of a swirling scavenging mode in a cylinder of a single-cylinder piston engine in the semi-dry semi-wet water cooling system according to the present invention;

FIG. 8 is a sectional view of the cylinder head structure of the cylinder of the single cylinder piston engine in the semi-dry semi-wet water cooling system according to the present invention;

FIG. 9 is a schematic view of the structure of the combined combustion chamber of the cylinder of the single-cylinder piston engine in the semi-dry semi-wet water cooling system according to the present invention;

fig. 10 is a schematic diagram of a cooling circuit of the semi-dry semi-wet water cooling system according to the present invention.

In the figure:

1-single cylinder piston engine cylinder 2-water inlet system 3-water outlet system

4-monoblock pump 101-cylinder block 102-cylinder head

103-cylinder jacket 104-cylinder head pressure plate 105-cylinder sealing gasket

106-cooling water inlet cavity 107-cooling water outlet cavity 108-cooling water flow channel

109-cooling water inlet joint 110-air inlet channel 111-exhaust channel

112-annular groove 113-web 114-water hole

115-coolant outlet connection 116-piston 117-stepped bore

118-sand cleaning port 119-water plug 120-pit structure

201-water pump B202-water inlet elbow A203-water inlet hose A

204-surge tank 205-water inlet hose 206-water inlet elbow B

301-water outlet connector 302-water outlet hose 303-water outlet tee joint

304-water outlet main pipe

Detailed Description

The invention is explained in further detail below with reference to the drawing.

The invention relates to a half-dry half-wet cooling system for a two-stroke aviation heavy oil piston engine body, wherein a cooling water flow channel is cast in a combined combustion chamber area of a single-cylinder piston engine cylinder 1, and cooling water in the cooling water flow channel is injected and discharged through a water inlet system 2 and a water outlet system 3, so that water cooling is implemented for the combined combustion chamber of the single-cylinder piston engine, as shown in figures 1 and 2.

The single-cylinder piston engine cylinder comprises a cylinder body 101, a cylinder head 102, a cylinder sleeve 103 and a cylinder head pressure plate 104, as shown in fig. 3. The cylinder block 101 has a cylindrical structure, and an internal thread is formed on an inner wall of a top end of the cylinder block. The cylindrical cylinder sleeve 103 is coaxially installed inside the cylinder block 101, and the outer wall of the cylindrical cylinder sleeve and the inner wall of the cylinder block 101 are assembled into a whole through small interference fit. An annular shoulder is designed at the top end of the cylinder sleeve 103 and is matched with an annular positioning table designed at the top of the inner wall of the cylinder block 101, so that the axial positioning between the cylinder sleeve 103 and the cylinder block 101 is realized; in order to ensure the assembly precision and ensure that the area of an assembly joint surface is as small as possible, the middle of the outer wall of the cylinder sleeve 103 is provided with a retraction section, and the retraction length is 1mm, so that the assembly difficulty of the cylinder block 101 and the cylinder sleeve 103 is reduced, and the assembly precision is improved. The cylinder head 102 is of a columnar structure, an external thread is designed on the outer cylindrical surface and matched with an internal thread on the inner wall of the top end of the cylinder body 101, and the thread is screwed into the top end of the cylinder body 101, coaxially fixed with the cylinder body 101 and used for compressing the cylinder sleeve 103 to axially fix the cylinder sleeve 103; a cylinder gasket 105 is arranged between the upper end surface of the cylinder sleeve 103 and the lower end surface of the cylinder head 102, so that sealing is realized, and water and air are prevented from entering the cylinder body 101; before the cylinder head 102 is assembled, the upper end surface of the adopted cylinder sealing gasket 105 needs to be slightly higher than the upper end surface of the cylinder sleeve 103; because the cylinder gasket 105 is made of soft material, after the cylinder head 102 is assembled, the cylinder gasket 105 is pressed by the cylinder head 102, and a good sealing effect can be ensured; through calculation and optimization design, the upper end face of the cylinder sealing gasket 105 is required to be higher than the upper end face of the cylinder sleeve 103 by about 0.05-0.15 mm, and if the height difference is smaller than 0.05mm, the single-cylinder piston engine cylinder can have the faults of air leakage, water return and the like, and if the height difference is larger than 0.15mm, the single-cylinder piston engine cylinder can have the faults of engine oil and cooling water mixing, cylinder head 102 deformation and even cracks and the like. The cylinder head pressing plate 104 arranged on the top surface of the cylinder head 102 is matched with a cylinder head nut through a cylinder head stud to tightly press and position the cylinder head pressing plate 104, and the cylinder head 102 is tightly pressed through the cylinder head pressing plate 104 to ensure the fixation between the cylinder head 102 and the cylinder body 101, so that the cylinder head 102 is not loosened.

The cooling water flow passage is provided in the cylinder block 101 and the cylinder head 102, as shown in fig. 3, 4, and 5. The cylinder surface of the inner wall of the cylinder block 101 is designed to be of a sectional structure, namely, the cylinder surface of the inner wall of the cylinder block 101 is discontinuous, small interference fit is formed between the inner cylinder wall surface and the cylinder sleeve 103 at the top, the middle and the bottom of the cylinder block 101, the inner cylinder wall surface is in dry contact with the outer wall of the cylinder sleeve 103, two annular cavities are formed between the bottom, the middle and the top of the cylinder block 101, namely a cooling water inlet cavity 106 and a cooling water outlet cavity 107, and the outer wall of the cylinder sleeve 103 is in direct contact with cooling liquid at the positions of the cooling water inlet cavity 106 and the cooling water outlet cavity 107. The cooling water inlet cavity 106 and the cooling water outlet cavity 107 are communicated through 4 cooling water channels 108 which are arranged in the middle of the cylinder block 101 along the axial direction of the cylinder block 101, and the cooling water channels in the cylinder block are formed by the cooling water inlet cavity 106 and the cooling water outlet cavity together. The lower end of the cylinder body 101 is designed with a cooling water inlet joint 109 which is communicated with a cooling water inlet cavity 106. The lower part of the cylinder block 101 is also designed with 2

inlet ports

110 and 1 outlet port 111, as shown in fig. 6; the air outlet ends of the two air inlet channels 110 are respectively communicated with two air inlets designed on the wall surface of the middle section of the cylinder sleeve 103; the air inlet end of the exhaust passage 111 is communicated with an exhaust port designed on the wall surface of the middle section of the cylinder sleeve 103; and the two intake port positions and the exhaust port positions are designed to be opposed to each other by 180 degrees with respect to the axis of the cylinder block 101. The 2 air inlets 110 are shaped like a free curved surface, and deflect a certain angle, preferably about 17 degrees, relative to the normal of the axis of the cylinder block 101 by adopting a design form of a tangential large elevation angle, and integrally tilt upwards for a certain angle; the exhaust passage is in a straight-line curved surface shape, is in a direct connection type and is matched with a rotor wing with low rotating speed, and the water tightness of the air inlet passage 110 and the exhaust passage 111 is ensured through the dry small interference fit between the cylinder body 101 and the cylinder sleeve 103, so that the air inlet passage 110 and the exhaust passage 111 of the cylinder body 101 are effectively isolated from a cooling water flow passage in the cylinder body. Therefore, air enters the combustion chamber from the two air inlet channels 110, and through the structural form of the air inlet channels 110 and the air outlet channels 111, the air flows towards the cylinder head 102 along the inner wall of the cylinder sleeve 103 in a spiral way, so that exhaust gas is forced to spiral downwards along the inner wall of the cylinder sleeve 103 and is discharged from the air outlet channels 111, and swirl scavenging is realized, as shown in fig. 7; and realize that many gas ports match through two intake ducts 110 and admit air, guarantee that the admission can be along cylinder jacket 103 inner wall spiral rising to the effectual scavenging short circuit of having avoided makes the scavenging have no dead zone at all, realizes layering scavenging, realizes layering combustion organization, has improved the intake efficiency, as shown in fig. 7.

An annular groove 112 is designed on the circumferential direction of the cylinder head 102, and 4 radial plates 113 are uniformly arranged on the inner circumference of the annular groove 112; the overall stiffness of the cylinder head 102 is increased by 4 webs 113 and the space between the webs 113 constitutes the cylinder head cooling water flow path, as shown in fig. 8. The bottom of the cylinder head 102 is circumferentially and uniformly provided with 4 water outlet holes, each water outlet hole is cast with 4 water holes 114 along the radial direction of the cylinder head 102, and the water holes 114 at the 4 water outlet holes are communicated with a cooling water channel in the cylinder head. The side wall of the top of the cylinder head 102 is provided with a cooling liquid outlet joint 115 which is communicated with a cooling water channel in the cylinder head.

A piston 116 is installed in the cylinder sleeve 103, and 1-3 oil-resistant and heat-resistant rubber sealing rings are sleeved on the matching surface of the piston 116 and the inner wall of the cylinder sleeve 103 to enhance the sealing effect. The lower end surface of the cylinder head 102 and the upper end surface of the piston 116 are designed with a pit structure 120, and a combined combustion chamber 1 is formed between the pit structure and the inner wall of the cylinder sleeve 103, as shown in fig. 9. The dimple arrangement 120 on the upper end of the piston 116 is formed by two continuous shallow dimples, which are omega-shaped in overall cross-section and serve as combustion chambers a. The pit structure 120 on the lower end face of the cylinder head is a U-shaped shallow pit structure with a side wall inclined outward and a bottom surface being a plane, and serves as a combustion chamber B. The combustion chamber C is defined inside the cylinder liner 2, and the combustion chamber a, the combustion chamber B, and the combustion chamber C together form a combined combustion chamber. Fuel oil and air in the combined combustion chamber are mixed in a space atomization mode, and atomized oil drops absorb heat from high-temperature air, evaporate and diffuse and are mixed with the air; the structure of the combustion chamber A is well matched with the oil spray oil beam, so that the air is distributed at the dense position of the oil beam of the combustion chamber, the air flow movement in the combustion chamber is promoted, and uniform mixed air is formed.

A stepped hole 117 penetrating through the upper end surface and the lower end surface of the cylinder head 102 is formed in the center of the cylinder head 102, and an internal thread is designed in the stepped hole 117 and is used for connecting the monoblock pump 4, so that the connecting end of the monoblock pump 4 is screwed into the stepped hole 117 through the internal thread, and the fixation between the monoblock pump 4 and the cylinder head 102 is realized; and the nozzle of the monoblock pump extends into the combined combustion chamber, and the spray hole of the nozzle is positioned in the combustion chamber B and exceeds the bottom surface of the combustion chamber B by 2 mm; meanwhile, the combustion chamber A, the combustion chamber B, the monoblock pump 4, the cylinder body 101 and the cylinder head 102 are on the same axis, and the design facilitates optimal matching of the penetration degree of the oil beam and the distance from the spray hole to the wall surface of the combined combustion chamber, so that heat flow and air flow are uniform.

The water inlet system 2 and the water outlet system 3 respectively realize the input and the discharge of the cooling liquid in the cooling water flow passage 108 in the combined combustion chamber of the single-cylinder piston engine cylinder 1, thereby realizing the cooling of the piston engine body. The two-stroke aviation heavy oil piston engine is provided with two combined combustion chambers which are all arranged in a corresponding single-cylinder piston engine cylinder 1; two single cylinder piston engine cylinders 1 are respectively installed on two sides of a crankcase through 4 cylinder head studs. Therefore, the water inlet system 2 of the present invention is designed to include a water pump 201, a water inlet elbow a202, a water inlet hose a203, a surge tank 204, a water inlet hose B205, and a water inlet elbow B206, as shown in fig. 1. Wherein, the water pump is arranged on the crankcase through a bracket; the outlet end of the water pump 201 is connected with the water inlet end of a water inlet hose A203 through a water inlet elbow A202; the water outlet end of the water inlet hose A203 is connected with the pressure stabilizing water tank 204. The surge tank 204 is installed on the engine bracket, the bilateral symmetry positions of the side walls are designed with water inlet connectors which are respectively connected with the water inlet ends of two water inlet hoses B205, and the water outlet ends of the two water inlet hoses 205 are connected with the cooling water inlet connectors 109 in the two combined combustion chambers 1 through water inlet elbows B206. Therefore, the cooling liquid enters the surge tank 204 from the outlet of the water pump 201 through the water inlet elbow A202 and the water inlet hose A203 in sequence, further flows through the water inlet hose B205 and the water inlet elbow B206 through the water joint on the surge tank, enters the annular cooling water inlet cavity 106 through the cooling water inlet joint 109, and enters the cooling water flow passage in the cylinder body, so that the cooling of the cylinder sleeve 103 is realized. Subsequently, the cooling liquid flows into the head inner cooling water flow passage 108 through the water holes 114 on the cylinder head 102, so as to cool the cylinder head 102; finally, the coolant is discharged from the coolant outlet joint into the water outlet system 2, as shown in fig. 10.

The water outlet system 3 includes a water outlet joint 301, a water outlet hose 302, a water outlet tee 303 and a water outlet main pipe 304, as shown in fig. 2. Wherein, the number of the water outlet joints 301 is two, and the water inlet ends are respectively connected with the cooling water outlet joints 120 in the two combined combustion chambers 1. The water outlet ends of the two water outlet joints 301 are respectively connected with the water inlet ends of the two water outlet hoses 302, the water outlet ends of the two water outlet hoses 302 are connected with the two opposite ends of the water outlet tee 303, and the other end of the water outlet tee is connected with the water outlet main pipe 304. The cooling liquid discharged from the cooling liquid outlet joint is sequentially gathered into the water outlet header pipe 304 through the water outlet joint 301, the water outlet hose 302 and the water outlet tee joint 303 to complete the whole cooling circulation work.

In the invention, 4 sand cleaning ports 118 are also arranged on the upper part of the cylinder body 101 in the circumferential direction and are communicated with a cooling water flow passage in the cylinder body, and a water plug 119 is arranged at each sand cleaning port 118 to plug the sand cleaning port; the inside of the cooling water flow passage is cleaned by the sand cleaning port 118 through the water discharge plug 119, as shown in fig. 3.

Claims

1. The utility model provides a two-stroke aviation heavy oil single cylinder piston engine cylinder with half dry semi-wet formula cooling system which characterized in that:

the engine cylinder comprises a cylinder body, a cylinder head, a cylinder sleeve and a cylinder head pressing plate, wherein the cylinder body is of a cylindrical structure, and an internal thread is designed on the inner wall of the top end of the cylinder body; the cylinder sleeve is coaxially arranged in the cylinder body, and the outer wall of the cylinder sleeve and the inner wall of the cylinder body are assembled into a whole in a small interference fit manner;

the top end of the cylinder sleeve is provided with an annular shoulder which is matched with an annular positioning table designed at the top of the inner wall of the cylinder block, so that the axial positioning between the cylinder sleeve and the cylinder block is realized; the middle of the outer wall of the cylinder sleeve is provided with an indentation section, and the indentation length is 1 mm; the cylinder head is of a columnar structure, the outer cylindrical surface is provided with an external thread which is matched with the internal thread on the inner wall of the top end of the cylinder body, and the thread is screwed into the top end of the cylinder body, coaxially fixed with the cylinder body and tightly pressed on the cylinder sleeve to realize the axial fixation of the cylinder sleeve;

a cylinder sealing gasket is arranged between the upper end surface of the cylinder sleeve and the lower end surface of the cylinder head, so that sealing is realized, and water and air are prevented from entering the cylinder body; before the cylinder head is assembled, the upper end face of the adopted cylinder sealing gasket is 0.05-0.15 mm higher than the upper end face of the cylinder sleeve;

a cylinder head pressing plate arranged on the top surface of the cylinder head is matched with a cylinder head nut through a cylinder head stud to tightly press and position the cylinder head, and the cylinder head is tightly pressed through the cylinder pressing plate to ensure the fixation between the cylinder head and the cylinder body;

the inner wall cylindrical surface of the cylinder block adopts a sectional structure, namely the inner wall cylindrical surface of the cylinder block is discontinuous, small interference fit is respectively formed among sections of inner cylindrical wall surfaces and the cylinder sleeve at the top, the middle and the bottom of the cylinder block, and the inner cylindrical wall surfaces are in dry contact with the outer wall of the cylinder sleeve, so that two annular cavities are formed between the bottom, the middle and the top of the cylinder block, namely a cooling water inlet cavity and a cooling water outlet cavity respectively, and the outer wall of the cylinder sleeve is directly contacted with cooling liquid at the positions of the cooling water inlet cavity and the cooling water outlet cavity; the cooling water inlet cavity and the cooling water outlet cavity are communicated through four cooling water flow channels which are arranged in the middle of the cylinder body in the circumferential direction and are arranged along the axial direction of the cylinder body, and the cooling water flow channels in the cylinder body are formed by the cooling water inlet cavity and the cooling water outlet cavity; the lower part of the cylinder body is provided with a cooling water inlet joint which is communicated with a cooling water inlet cavity;

an annular groove is designed on the circumferential direction of the cylinder head, and four amplitude plates are uniformly arranged on the inner circumference of the annular groove; the space between each plate forms a cylinder head internal cooling water flow channel, four water outlet hole sites are uniformly distributed on the bottom of the cylinder head in the circumferential direction, four water holes are cast at each water outlet hole site along the radial direction of the cylinder head, the water holes at the four water outlet hole sites are communicated with the cylinder head internal cooling water flow channel, and a cooling liquid outlet joint is mounted on the side wall of the top of the cylinder head and communicated with the cylinder head internal cooling water flow channel;

the lower part of the cylinder body is also provided with two air inlet channels and an air outlet channel, and the air outlet ends of the two air inlet channels are respectively communicated with two air inlets arranged on the wall surface of the middle section of the cylinder sleeve; the air inlet end of the exhaust passage is communicated with an exhaust port designed on the wall surface of the middle section of the cylinder sleeve; the positions of the two air inlets and the position of the two air outlets are opposite to each other by 180 degrees relative to the axis of the cylinder body; the two air inlet channels are in a free-form surface shape, a design form of a tangential large elevation angle is adopted, the deflection angle of the air inlet channels relative to the normal of the axis of the cylinder body is 17 degrees, and the air inlet channels integrally tilt upwards for a certain angle; the exhaust passage is in a straight grain curved surface shape, is in a direct connection type, is matched with a rotor wing with low rotating speed, and is matched with the cylinder sleeve in a dry type small interference manner through the cylinder body, so that air enters the combustion chamber from the two air inlet passages;

a piston is arranged in the cylinder sleeve, and one to three oil-resistant and heat-resistant rubber sealing rings are sleeved on the matching surface of the piston and the inner wall of the cylinder sleeve; a pit structure is designed on the lower end surface of the cylinder head and the upper end surface of the piston, and a combined combustion chamber is formed between the pit structure and the inner wall of the cylinder sleeve; the method specifically comprises the following steps: the pit structure on the upper end face of the piston is formed by two continuous shallow pits, the whole cross section of the pit structure is omega-shaped and serves as a combustion chamber A, the pit structure on the lower end face of the cylinder head is of a U-shaped shallow pit structure with the side wall inclined outwards, the bottom face of the pit structure is a plane and serves as a combustion chamber B, the interior of the cylinder sleeve serves as a combustion chamber C, and the combustion chamber A, the combustion chamber B and the combustion chamber C form a combined combustion chamber together;

the center of the cylinder head is provided with a stepped hole which penetrates through the upper end surface and the lower end surface of the cylinder head, the stepped hole is provided with an internal thread and is used for connecting the monoblock pump, so that the connecting end of the monoblock pump is screwed into the stepped hole through the internal thread to realize the fixation between the monoblock pump and the cylinder head; and the nozzle of the monoblock pump extends into the combined combustion chamber, and the spray hole of the nozzle is positioned in the combustion chamber B and exceeds the bottom surface of the combustion chamber B by 2 mm; and meanwhile, the combustion chamber A, the combustion chamber B, the monoblock pump, the cylinder body and the cylinder head are ensured to be on the same axis.

2. The cylinder of the two-stroke aviation heavy oil single-cylinder piston engine with the semi-dry and semi-wet cooling system as claimed in claim 1, wherein: and the water inlet system and the water outlet system are adopted to respectively realize the input and the discharge of the cooling liquid in the cooling water flow channel in the combined combustion chamber of the cylinder of the two-stroke aviation heavy oil single-cylinder piston engine, so that the engine body is cooled.

3. The cylinder of the two-stroke aviation heavy oil single-cylinder piston engine with the semi-dry and semi-wet cooling system as claimed in claim 2, wherein: the two-stroke aviation heavy oil single-cylinder piston engine is provided with two combined combustion chambers which are both arranged in corresponding single-cylinder piston engine cylinders; two single cylinder piston engine cylinders are respectively installed on two sides of the crankcase through 4 cylinder head studs.

4. The cylinder of the two-stroke aviation heavy oil single-cylinder piston engine with the semi-dry and semi-wet cooling system as claimed in claim 2, wherein: the water inlet system comprises a water pump, a water inlet elbow A, a water inlet hose A, a pressure stabilizing water tank, a water inlet hose B and a water inlet elbow B, and the water pump is arranged on the crankcase through a bracket; the outlet end of the water pump is connected with the water inlet end of a water inlet hose A through a water inlet elbow A; the water outlet end of the water inlet hose A is connected with the pressure stabilizing water tank; the pressure stabilizing water tank is arranged on an engine bracket, water inlet joints are designed at the left and right symmetrical positions of the side wall and are respectively connected with the water inlet ends of the two water inlet hoses B, and the water outlet ends of the two water inlet hoses B are connected with the cooling water inlet joints in the two combined combustion chambers through the water inlet elbows B.

5. The cylinder of the two-stroke aviation heavy oil single-cylinder piston engine with the semi-dry and semi-wet cooling system as claimed in claim 2, wherein: the water outlet system comprises two water outlet connectors, two water outlet hoses, two water outlet tee joints and a water outlet header pipe, wherein the water inlet ends of the two water outlet connectors are respectively connected with the cooling water outlet connectors in the two combined combustion chambers, the water outlet ends of the two water outlet connectors are respectively connected with the water inlet ends of the two water outlet hoses, the water outlet ends of the two water outlet hoses are connected with the two opposite ends of the water outlet tee joints, and the other ends of the water outlet tee joints are connected with the water outlet header pipe.

6. The cylinder of the two-stroke aviation heavy oil single-cylinder piston engine with the semi-dry and semi-wet cooling system as claimed in claim 1, wherein: the upper part of the cylinder body is also provided with 4 sand cleaning ports along the circumferential direction, the sand cleaning ports are communicated with a cooling water flow passage in the cylinder body, and a water plug is arranged at each sand cleaning port to plug the sand cleaning port.