Engine cooling circulation system

Abstract

The invention relates to the technical field of marine engines, and discloses an engine cooling circulation system which comprises an engine body used for cooling an engine, a closed high-temperature cooling circulation of a lubricating oil cooler and a closed low-temperature cooling circulation used for cooling an air cooler. The closed high-temperature cooling circulation and the closed low-temperature cooling circulation share a set of fresh water pumps to provide power and share a set of combined heat exchangers to achieve heat exchange between the closed cooling circulation and the open cooling circulation. The closed high-temperature cooling circulation comprises water rails arranged on the two sides of the engine body, one end of each water rail is communicated with a fresh water pump, the side face of each water rail is provided with a branch communicated with the cylinder cover of the engine body so as to cool the cylinder cover firstly and then cool the cylinder sleeve, and adverse effects on internal parts of the cylinder cover are avoided; a front-end housing is arranged on the front side of the machine body, and fresh water after cooling the cylinder sleeve is converged to the front-end housing and led to the lubricating oil cooler; the number of engine parts can be reduced, and the overall mass of an engine is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of marine engines, in particular to an engine cooling circulation system. Background Art

[0002] The main function of the engine cooling system is to ensure that the engine works at the most suitable temperature. When the working conditions and environmental conditions change, the internal combustion engine can still work reliably. Marine engines are generally divided into closed cooling circulation systems and open cooling circulation systems. The closed cooling circulation system relies on fresh water for circulation cooling, and the open cooling circulation system can use seawater to circulate and cool fresh water. The closed cooling circulation system is divided into two circuits: high-temperature circulation cooling and low-temperature circulation cooling. However, the existing V-type marine engine cooling circulation system has the following problems:

[0003] (1) The high-temperature and low-temperature fresh water cooling circulation method uses two independent fresh water pumps for high-temperature cooling circulation and low-temperature cooling circulation respectively. At the same time, two plate heat exchangers for high-temperature cooling and low-temperature cooling are configured accordingly. This makes the overall pipeline structure of the engine complex, with many leakage points, complex installation and is not conducive to the lightweight design of the engine body.

[0004] (2) Regarding the cooling method of the cylinder liner, fresh water enters the engine body, first cools the engine cylinder liner, then enters the cylinder head for cooling, and then is collected in the lubricating oil cooler. However, the cooling water after cooling the engine cylinder liner enters the cylinder head again, so that the higher temperature of the cooling water has an adverse effect on the cooling of the internal components of the cylinder head, which can easily cause fatigue failure of the cylinder head. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an engine cooling circulation system, in which a closed high-temperature cooling cycle and a closed low-temperature cooling cycle share a group of fresh water pumps for power supply and a group of combined heat exchangers, which can reduce the number of engine parts, reduce pipelines, reduce the overall weight of the engine, and save costs; by arranging a water rail, fresh water first cools the cylinder head and then cools the cylinder liner, avoiding the adverse effect of high-temperature fresh water on the cooling of internal parts of the cylinder head, and preventing the cylinder head from fatigue failure in a relatively short period of time.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] An engine cooling cycle system includes a closed high-temperature cooling cycle for cooling an engine body and a lubricating oil cooler and a closed low-temperature cooling cycle for cooling an air cooler, wherein the closed high-temperature cooling cycle and the closed low-temperature cooling cycle share a group of fresh water pumps for power supply and a group of combined heat exchangers for realizing heat exchange between the closed cooling cycle and the open cooling cycle;

[0008] The closed high-temperature cooling cycle includes water rails arranged on both sides of the engine body. One end of the water rail is used to connect to the fresh water pump. The side is provided with branches connected to the positions of the cylinder heads of the engine body to cool the cylinder heads first and then the cylinder liners. A front end cover is provided on the front side of the engine body. The fresh water after cooling the cylinder liners converges into the front end cover and leads to the lubricating oil cooler.

[0009] As a further implementation method, the high-temperature side water channel of the combined heat exchanger is integrated in a closed high-temperature cooling circulation loop, and the low-temperature side of the combined heat exchanger is integrated in a closed low-temperature cooling circulation loop; the low-temperature side of the combined heat exchanger is installed on the front end cover.

[0010] As a further implementation method, the closed high-temperature cooling cycle loop is composed of a fresh water pump, a water rail, a machine body, a lubricating oil cooler, a thermostatic valve, and a high-temperature side of a combined heat exchanger arranged in sequence. The thermostatic valve is a three-way structure so that its bypass port can be directly connected to the fresh water pump; the thermostatic valve adjusts the flow of fresh water entering the high-temperature side of the combined heat exchanger according to the different temperature ranges of the fresh water.

[0011] As a further implementation, the water rail includes a first water rail and a second water rail arranged on both sides of the machine body, and one end of the first water rail and the second water rail are connected to the fresh water pump through a water channel of the front end cover.

[0012] As a further implementation method, the closed low-temperature cooling cycle loop is composed of a fresh water pump, a low-temperature side of a combined heat exchanger, a converging three-way valve, and an air cooler arranged in sequence. The fresh water pump is also connected to the air cooler through a converging three-way valve. The converging three-way valve controls the flow of fresh water entering the low-temperature side of the combined heat exchanger according to the outlet temperature of the air cooler.

[0013] As a further implementation, temperature sensors are provided on the inlet pipeline of the thermostatic valve and the outlet gas path of the air cooler to serve as a basis for adjusting the opening of the thermostatic valve and the converging three-way valve, respectively.

[0014] As a further implementation method, the high temperature side of the combined heat exchanger is provided with a water channel connected to the open cooling circulation loop, the water outlet of the seawater pump is connected to the water inlet of the combined heat exchanger through a one-way valve, and the fresh water in the closed cooling circulation loop is cooled by seawater.

[0015] As a further implementation, when the fresh water temperature is within the first temperature range, the thermostatic valve closes the passage leading to the combined heat exchanger to allow all the fresh water to flow back to the fresh water pump;

[0016] When the fresh water temperature is in the second temperature range, the thermostatic valve begins to gradually open the passage to the combined heat exchanger and reduces the opening of the fresh water directly returning to the pump so that part of the fresh water returns to the fresh water pump after being cooled by the combined heat exchanger;

[0017] When the fresh water temperature is within the third temperature range, the thermostatic valves all open the passages leading to the combined heat exchanger and close the passages leading to the fresh water pump, so that all the fresh water returns to the fresh water pump after being cooled by the combined heat exchanger.

[0018] As a further implementation, when the outlet temperature of the air cooler is lower than the set value, the converging three-way valve closes the passage between the converging three-way valve and the low-temperature side of the combined heat exchanger, so that the fresh water directly enters the air cooler after passing through the converging three-way valve;

[0019] When the outlet temperature of the air cooler is higher than the set value, the passage between the closing of the converging three-way valve and the low-temperature side of the combined heat exchanger begins to open, and the opening of the passage for fresh water to directly enter the air cooler after passing through the converging three-way valve begins to decrease until the fresh water temperature stabilizes at the set value and reaches equilibrium.

[0020] As a further implementation, the lubricating oil cooler, the cylinder head, the front end cover, and the air cooler are all connected to an expansion water tank via an air bleed pipe, and a pressure limiting valve is provided on the expansion water tank to automatically exhaust air when the pressure reaches a predetermined pressure.

[0021] The beneficial effects of the present invention are as follows:

[0022] The closed high-temperature cooling cycle and the closed low-temperature cooling cycle of the present invention share a group of fresh water pumps for power supply, and share a group of combined heat exchangers to realize heat exchange between the closed cooling cycle and the open cooling cycle, which can reduce the number of engine parts, reduce pipelines, reduce the overall weight of the engine, and save costs; by arranging a water rail, the fresh water first cools the cylinder head and then cools the cylinder liner, thereby avoiding the adverse effect of high-temperature fresh water on the cooling of internal parts of the cylinder head and preventing the cylinder head from fatigue failure in a relatively short time; by fixing the thermostatic valve, the converging three-way valve, the combined heat exchanger, the expansion water tank, and the seawater pump on the engine, the overall integration of the engine is effectively improved, and the overall structure of the engine is made more compact. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 is a flow chart of an engine cooling cycle system in an embodiment of the present invention;

[0025] Figure 2 is a schematic diagram of the overall structure of an engine in an embodiment of the present invention;

[0026] Figure 3 is a schematic cross-sectional structural diagram of a cylinder liner portion of an engine in an embodiment of the present invention;

[0027] Figure 4 is a schematic cross-sectional structural diagram of the engine water rail portion in an embodiment of the present invention;

[0028] Figure 5 is a schematic diagram of the cross-sectional structure of the water rail portion of the engine in an embodiment of the present invention;

[0029] Figure 6 Schematic diagram of the cooling circulation flow of the cylinder liner of the engine in an embodiment of the present invention;

[0030] Figure 7 Schematic diagram of high temperature cooling cycle flow in an embodiment of the present invention;

[0031] Figure 8 Schematic diagram of the cooling cycle flow direction of the thermostatic valve part in the embodiment of the present invention;

[0032] Fig. 9 Schematic diagram of low temperature cooling cycle flow in an embodiment of the present invention;

[0033] Fig.10 Schematic diagram of the cooling cycle flow direction of the converging three-way valve part in the embodiment of the present invention;

[0034] Fig.11 is a schematic diagram of a local structure of an engine in an embodiment of the present invention;

[0035] Fig.12 It is a schematic diagram of the inner side structure of the combined heat exchanger in an embodiment of the present invention.

[0036] In the figure: the distances or sizes between parts are exaggerated to show the positions of various parts, and the schematic diagram is for reference only.

[0037] Among them: 1. Fresh water pump; 2. Water rail; 21. First water rail; 22. Second water rail; 3. Expansion water tank; 4. Air cooler; 5. Temperature regulating valve; 6. Lubricating oil cooler; 7. Converging three-way valve; 8. Front end cover; 9. Combined heat exchanger; 10. Seawater pump; 11. Engine body; 12. Cylinder head; 13. Cylinder liner; 14. Fresh water pump inlet. DETAILED DESCRIPTION

[0038] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0039] Embodiment 1

[0040] In a typical embodiment of the present invention, reference is made to Figure 1-Figure 12As shown, an engine cooling circulation system, the engine includes a body 11, a fresh water pump 1, a water rail 2, an expansion water tank 3, an air cooler 4, a thermostatic valve 5, an oil cooler 6, a converging three-way valve 7, a front end cover 8, a combined heat exchanger 9, a seawater pump 10, a cylinder head 12, a cylinder liner 13 and a fresh water pump inlet 14.

[0041] The engine cooling circulation system of this embodiment consists of an open circulation cooling system and a closed circulation cooling system. The medium of the open circulation cooling system is seawater; the medium of the closed circulation cooling system is fresh water containing 20% ​​ethylene glycol. In the closed circulation cooling system, the fresh water is divided into a high-temperature cooling circulation and a low-temperature cooling circulation after passing through a fresh water pump 1.

[0042] like Figure 2 As shown, a front cover 8 is installed at the front end of the machine body 11, and water rails 2 are provided on the left and right sides of the machine body. Figure 5 As shown, they are the first water rail 21 and the second water rail 22, respectively. The first water rail 21 is located on the left side of the engine body, and the second water rail 22 is located on the right side of the engine body 11. An air cooler 4 is installed in the middle of the top of the engine body 11, and a lubricating oil cooler 6 is installed on the side of the air cooler 4 close to the front end cover 8. An expansion water tank 3 is provided on the top of the engine body close to the first water rail 21 of the lubricating oil cooler 6, and a thermostatic valve 5 is provided at the top of the front end cover 8 close to the left side. A converging three-way valve 7 is provided close to the right side, and a combined heat exchanger 9 is provided at the front side of the front end cover 8 close to the top. Two groups of cylinder heads 12 and cylinder sleeves 13 are provided on the left and right sides of the engine body, respectively, and each group is arranged side by side. The engine is a V-type engine.

[0043] The front side of the front cover 8 cooperates with the fresh water pump 1 and the sea water pump 10. The water outlets of the fresh water pump 1 and the sea water pump 10 cooperate with the front cover 8 through pipelines with one-way valves. The pumps are located below the combined heat exchanger 9, wherein the fresh water pump 1 is located on the left side and the sea water pump 10 is located on the right side; wherein the water rail corresponds to the height of the cylinder head 12. The engine is cooled by the above structure.

[0044] It can be understood that the front end cover 8 is provided with corresponding water channels to realize the circulation of high-temperature cooling water and low-temperature cooling water.

[0045] In a closed-loop cooling system, the high-temperature cooling cycle:

[0046] like Figure 1 As shown, fresh water is squeezed out by the fresh water pump 1 and divided into four paths, two of which are high-temperature circulating water, participating in the high-temperature cooling cycle. Figure 4As shown, fresh water enters the fresh water pump inlet 14 on the front cover 8 through the fresh water pump 1, and is divided into two paths through the fresh water pump inlet 14 in the front cover 8, entering the first water rail 21 through the first water channel and entering the second water rail 22 through the second water channel. The water rail is provided with a plurality of branches to communicate with the cavity at the cylinder head 12 in the engine body. The high-temperature circulating water in the water rail is divided into the cavities of the cylinder heads 12 on both sides of the engine body 11, first cooling the cylinder heads 12, and then entering the water cavity of the engine body 11 to cool the cylinder sleeves 13. The high-temperature circulating water after cooling the cylinder sleeves 13 is passed through the Figure 7 As shown in the figure, after the internal cavity of the engine body 11 is collected, the water flows upward through the front cover 8 into the lubricating oil cooler 6, and then the lubricating oil is cooled. Figure 5-Figure 8 shown.

[0047] The thermostatic valve 5 is a three-way valve structure, and its three ports are port A, port B and port C, port B is a bypass port, the high temperature side of the combined heat exchanger 9 is located outside it, and has port M and port N connected by a water channel, wherein port M is the high temperature side inlet, and port N is the high temperature side outlet, both of which are close to the top of the combined heat exchanger 9. Fig.11 shown.

[0048] The outlet of the lubricating oil cooler 6 is connected to the A port of the thermostatic valve 5 through the internal water channel of the front end cover 8. Figure 8 As shown, port B is connected to the inlet of the fresh water pump 1 through a water channel, port C is connected to port M on the high temperature side of the combined heat exchanger 9 through a pipeline, and the fresh water enters the thermostatic valve 5 after passing through the lubricating oil cooler 6. A temperature sensor is provided on the inlet pipeline of the thermostatic valve 5 to detect the fresh water temperature.

[0049] like Figure 8 and Figure 1 As shown, in the first temperature range, when the fresh water temperature is less than 90°C, the cooling port C of the thermostatic valve 5 is completely closed, the fresh water cannot enter the combined heat exchanger 9, and the bypass port B is completely opened. At this time, the fresh water does not need to be cooled by the combined heat exchanger 9, and the high-temperature side fresh water coming out of the port B flows back to the fresh water pump 1 through the waterway; in the second temperature range, when the water temperature is ≥90°C and less than 105°C, as the water temperature gradually rises, the cooling port C of the thermostatic valve 5 begins to open and enters the port M of the combined heat exchanger 9 for heat exchange. After being cooled, it flows out from the N port of the combined heat exchanger 9 and enters the fresh water pump 1, and the opening of the bypass port B begins to decrease; in the third temperature range, when the water temperature is ≥105℃, the bypass port B of the thermostatic valve 5 is completely closed, and the cooling port C of the thermostatic valve 5 is completely opened. The fresh water on the high-temperature side all enters the M port of the combined heat exchanger 9 for heat exchange and cooling first, and then flows out from the N port of the combined heat exchanger after being cooled. After being cooled by the combined heat exchanger 9, the fresh water on the high-temperature side returns to the fresh water pump 1 for the next cycle.

[0050] In a closed-loop cooling system, low-temperature cooling cycle:

[0051] like Fig. 9As shown, fresh water is pressed out by the fresh water pump 1 and divided into four paths, and the other two paths are low-temperature circulating water, which participate in the low-temperature cooling cycle. Fresh water enters the fresh water pump inlet 14 on the front cover 8 through the fresh water pump 1, and is divided into two other paths through the fresh water pump inlet 14 in the front cover 8. The front cover 8 is provided with a D port. After entering the D port, the fresh water can be connected to the F port on the right side of the front cover 8 through the third water channel, and connected to the E port on the left side of the front cover 8 through the fourth water channel, so that the low-temperature circulating water fresh water is pressurized by the fresh water pump 1 and enters Fig. 9 Cross-sectional view of ports E and F. Fresh water that does not enter port D enters water rail 2.

[0052] like Fig.12 As shown, the low-temperature side of the combined heat exchanger 9 is located on the inner side thereof, and has a P port and an O port, both of which are close to the top of the combined heat exchanger 9, and are adapted to the height of the M port at the N port. The P port and the O port are connected through the internal water channel of the combined heat exchanger 9, wherein the O port is the inlet and the P port is the outlet.

[0053] The E port on the front end cover 8 is connected to the O port on the low temperature side inlet of the combined heat exchanger. A G port is also provided on the right side of the outer side of the front end cover 8. The G port is connected to the P port on the low temperature side outlet of the combined heat exchanger, so that low temperature water can pass through the E port, O port, P port and G port in sequence.

[0054] like Figure 1 and Fig.10 As shown, the three ports of the confluence type three-way valve are respectively connected to the H port, the F port and the J port, and the J port is connected to the air cooler 4 through the water channel. The G port is connected to the H port of the confluence type three-way valve 7 through the water channel on the front cover 8. A temperature sensor is provided on the outlet gas path of the air cooler 4, and the temperature sensor can send a temperature signal to the monitoring instrument.

[0055] The converging three-way valve 7 is a DV24V electric structure. Its working principle is that when the monitoring instrument is equipped with a temperature sensor, the outlet temperature of the air cooler 4 can be detected. When the outlet temperature is lower than the set temperature of 40°C, the H port of the converging three-way valve 7 is closed and the F port is opened, so that the F port is connected to the J port, and fresh water can enter the air cooler to cool the high-temperature air.

[0056] When the outlet air temperature is greater than the set temperature of 40°C, the H port of the converging three-way valve begins to open, the opening of the F port decreases, and both the F port and the H port are connected to the J port. The fresh water can directly enter the air cooler 4 through the third water channel and the F port and the J port, and can also return to the H port through the fourth water channel, the E port, the O port, the P port and the G port in sequence. After being cooled on the low-temperature side of the combined heat exchanger 9, it enters the air cooler 4 through the J port.

[0057] Fresh water enters the air cooler 4 to cool the high-temperature air. As the opening of port H increases, more low-temperature water enters the air cooler 4, and the temperature of the air cooler 4 gradually decreases until the outlet temperature of the air cooler 4 reaches the set temperature of 40°C, and the openings of port H and port F of the converging three-way valve finally reach a balance.

[0058] like Figure 1 and Fig.11 As shown, in the open-cycle cooling system, a K port and an L port are provided at the lower position of the high-temperature side of the combined heat exchanger, wherein the K port is located below the N port, and the L port is located below the M port, and the K port and the L port are connected through the internal water channel of the combined heat exchanger 9.

[0059] Seawater is pumped into the K port of the combined heat exchanger through the seawater pump 10 and the one-way valve, and flows out from the L port of the combined heat exchanger after heat exchange with the high-temperature side closed-loop cooling water and the low-temperature side closed-loop cooling water in the combined heat exchanger.

[0060] like Figure 1 As shown, since bubbles are generated during the operation of the engine, in order to reduce the risk of water pump cavitation and cylinder liner cavitation, improve the cooling effect, and improve the reliability of the engine, a vent pipe is provided at the engine cylinder head 12, the air cooler 4, the front cover 8, and the lubricating oil cooler 6. The vent pipe is connected to the expansion tank 3, and the expansion tank 3 is provided with a pressure limiting valve. When the pressure in the expansion tank 3 reaches a predetermined pressure, the expansion tank 3 is automatically exhausted, and the cooling fresh water at the bottom of the expansion tank 3 is added to the cooling circulation system in time. It can be understood that a spare water inlet is provided at the fresh water pump inlet and the sea water pump outlet and the fresh water pump outlet.

[0061] The combined heat exchanger 9 has a pressure plate structure on both sides, which is installed on the engine through the low-temperature side pressure plate. The high-temperature side is at the seawater inlet end, and the low-temperature side is fitted on the engine front cover 8. There is a partition between the high-temperature side and the low-temperature side. Seawater at about 32°C enters the combined heat exchanger 9, and the fresh water with a temperature greater than 90°C (high-temperature cooling cycle) and the fresh water at about 85°C (low-temperature cooling cycle) on the low-temperature side are cooled separately through the common channel. The pressure plates on the high-temperature side and the low-temperature side of the combined heat exchanger are made of titanium alloy.

[0062] It is understandable that in the high-temperature cooling cycle, the temperature of the cooling fresh water pumped into the engine by the fresh water pump 1 is 85°C, ensuring that the cooling fresh water entering the engine will not cause the cylinder liner 13 to produce cavitation too quickly; the circulation system can calculate the flow rate of the cooling fresh water by the heat exchange of the lubricating oil cooler 6, ensuring that the temperature of the cooling fresh water after the heat exchange in the lubricating oil cooler 6 reaches the preset temperature of 90°C. The control temperature of the thermostatic valve 5 is set to 90°C to open, and the full opening temperature is 105°C. When the thermostatic valve 5 is set to operate stably, the opening of the thermostatic valve cooling port is 60%, and the opening of the bypass port is 40%. The temperature of the fresh water outlet on the high-temperature side of the combined heat exchanger 9 and the bypass outlet of the thermostatic valve is set to 85°C after mixing, so that the mixed fresh water can return to the fresh water pump for circulation.

[0063] It can be understood that in the low-temperature cooling cycle, the fresh water pump 1 pumps into the converging three-way valve 7 and the combined heat exchanger 9. The low-temperature side inlet fresh water temperature is 85°C. After the fresh water is cooled on the low-temperature side of the combined heat exchanger 9, it enters the converging three-way valve 7 and mixes with the fresh water before entering the air cooler 4. The converging three-way valve 7 is an electric type, and the valve opening is controlled by receiving the temperature of the air cooler 4, thereby controlling the flow rate of fresh water flowing into the air cooler 4 from the low-temperature side of the combined heat exchanger 9 to achieve the air cooling effect.

[0064] The pressure plates at both ends of the combined heat exchanger 9 are made of titanium alloy, which reduces the overall weight of the engine, improves the strength of the plate heat exchanger, and can be installed on the end face of the engine. It can also be used as a monitor, fuel filter, ECU and other ancillary products fixed on the combined heat exchanger. By using a high and low temperature combined heat exchanger, the high and low temperature heat exchange plates are fixed between the two pressure plates, which reduces the number of pressure plates and achieves high integration and lightweight.

[0065] In the closed-loop cooling system of this embodiment, the high and low temperature fresh water pumps required for the high temperature cooling cycle and the low temperature cooling cycle are combined into one fresh water pump, which can reduce the number of engine parts, reduce pipelines, and reduce the overall weight of the engine. A fresh water pump is used to establish a pressure difference between the high temperature circulation system and the low temperature circulation system, drive the cooling medium to transfer heat energy between various functional parts, and collect the outlet temperature of the air cooler 4, adjust the opening of the confluence type three-way valve 7 to control the flow of fresh water entering the air cooler 4 to achieve precise control.

[0066] In the high-temperature cooling cycle, the cylinder liner 13 is cooled in a top-down manner, that is, after the fresh water is pumped out by the fresh water pump 1, it is divided into four paths, two of which are high-temperature circulating water, which enter the water rails 2 on the left and right sides of the engine respectively, and are diverted to the water chambers of the cylinder heads 12 on both sides to cool the cylinder heads 12, and then enter the water chamber of the engine body 11 to cool the cylinder liner 12, thereby avoiding the risk of fatigue failure of the internal parts of the cylinder head 12; the fresh water is collected by the cylinder liner 13 and enters the lubricating oil cooler through the water channel of the front cover 8 to cool the lubricating oil, thereby improving the thermal efficiency of the engine.

[0067] The combined heat exchanger structure and material selection of this embodiment are compact in structure. The new structure and new material combined plate heat exchanger, compared with the traditional plate heat exchanger, uses a set of combined heat exchangers, which is equivalent to reducing the mass of two steel plate pressure plates by about 209kg. The use of new material heat exchanger pressure plates reduces the mass by 120kg, and reduces the overall mass of the engine by 329kg.

[0068] By fixing the thermostatic valve 5, the confluence three-way valve 7, the combined heat exchanger 9, the expansion water tank 3, and the seawater pump 10 on the engine, the overall integration of the engine is effectively improved, and the overall structure of the engine is made more compact. The cooling circulation system of this embodiment can not only solve the problem of engine installation space and reduce the overall weight of the engine, but also improve the intelligent control of the engine and improve the thermal efficiency of the engine. All the parts required for the cooling system are installed on the engine, and the system is self-contained, which reduces the workload of on-site installation of the whole machine, is convenient for users to install on site, has a neat appearance, is easy to operate and install, is safe and reliable, and has strong usability.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An engine cooling circulation system, characterized in that: The invention comprises a closed high-temperature cooling cycle for cooling the engine body and the lubricating oil cooler and a closed low-temperature cooling cycle for cooling the air cooler, wherein the closed high-temperature cooling cycle and the closed low-temperature cooling cycle share a group of fresh water pumps for power supply, and share a group of combined heat exchangers for realizing heat exchange between the closed cooling cycle and the open cooling cycle; The closed high-temperature cooling cycle includes water rails arranged on both sides of the engine body. One end of the water rail is used to connect to the fresh water pump. The side is provided with branches connected to the positions of the cylinder heads of the engine body to cool the cylinder heads first and then the cylinder liners. A front end cover is provided on the front side of the engine body. The fresh water after cooling the cylinder liners converges into the front end cover and leads to the lubricating oil cooler.

2. An engine cooling circulation system according to claim 1, characterized in that: The high-temperature side water channel of the combined heat exchanger is integrated in a closed high-temperature cooling circulation loop, and the low-temperature side of the combined heat exchanger is integrated in a closed low-temperature cooling circulation loop; the low-temperature side of the combined heat exchanger is installed on the front end cover.

3. An engine cooling circulation system according to claim 1, characterized in that: The closed high-temperature cooling cycle loop is composed of a fresh water pump, a water rail, a machine body, a lubricating oil cooler, a thermostatic valve, and a high-temperature side of a combined heat exchanger, which are arranged in sequence. The thermostatic valve is a three-way structure so that its bypass port can be directly connected to the fresh water pump; the thermostatic valve adjusts the flow of fresh water entering the high-temperature side of the combined heat exchanger according to the different temperature ranges of the fresh water.

4. An engine cooling circulation system according to claim 3, characterized in that: The water rails include a first water rail and a second water rail arranged on both sides of the machine body. One end of the first water rail and the second water rail are both connected to the fresh water pump through the water channel of the front end cover.

5. The engine cooling circulation system according to claim 3, characterized in that: The closed low-temperature cooling cycle loop is composed of a fresh water pump, a low-temperature side of a combined heat exchanger, a converging three-way valve, and an air cooler arranged in sequence. The fresh water pump is also connected to the air cooler through a converging three-way valve. The converging three-way valve controls the flow of fresh water entering the low-temperature side of the combined heat exchanger according to the outlet temperature of the air cooler.

6. An engine cooling circulation system according to claim 5, characterized in that: The inlet pipeline of the thermostatic valve and the outlet gas path of the air cooler are provided with temperature sensors, which serve as the basis for adjusting the opening of the thermostatic valve and the converging three-way valve respectively.

7. An engine cooling circulation system according to claim 1, characterized in that: The high temperature side of the combined heat exchanger is provided with a water channel connected to the open cooling circulation loop, the water outlet of the seawater pump is connected to the water inlet of the combined heat exchanger through a one-way valve, and the fresh water on the closed cooling circulation loop is cooled by seawater.

8. An engine cooling circulation system according to claim 3, characterized in that: When the fresh water temperature is within the first temperature range, the thermostatic valve closes the passage leading to the combined heat exchanger so that all the fresh water flows back to the fresh water pump; When the fresh water temperature is in the second temperature range, the thermostatic valve begins to gradually open the passage to the combined heat exchanger and reduces the opening of the fresh water directly returning to the pump so that part of the fresh water returns to the fresh water pump after being cooled by the combined heat exchanger; When the fresh water temperature is within the third temperature range, the thermostatic valves all open the passages leading to the combined heat exchanger and close the passages leading to the fresh water pump, so that all the fresh water returns to the fresh water pump after being cooled by the combined heat exchanger.

9. The engine cooling circulation system according to claim 5, characterized in that: When the outlet temperature of the air cooler is lower than the set value, the confluence three-way valve closes the passage between the confluence three-way valve and the low-temperature side of the combined heat exchanger, so that the fresh water directly enters the air cooler after passing through the confluence three-way valve; When the outlet temperature of the air cooler is higher than the set value, the passage between the closing of the converging three-way valve and the low-temperature side of the combined heat exchanger begins to open, and the opening of the passage for fresh water to directly enter the air cooler after passing through the converging three-way valve begins to decrease until the fresh water temperature stabilizes at the set value and reaches equilibrium.

10. An engine cooling circulation system according to claim 5, characterized in that: The lubricating oil cooler, the cylinder head, the front end cover, and the air cooler are all connected to an expansion water tank through an air bleed pipe. A pressure limiting valve is provided on the expansion water tank to automatically exhaust air when the pressure reaches a predetermined pressure.

Images