A marine engine step cooling after intercooler temperature closed loop regulation system and method

Abstract

The application discloses a kind of ship machine grading cooling's post-intercooling temperature closed-loop regulation system and method, it is related to ship cooling control technical field, including fresh water pump and seawater pump, seawater pump is sequentially connected with intercooler and heat exchanger by pipeline to form outer cooling circulation loop, fresh water pump is sequentially connected with intercooler, engine, heat exchanger by pipeline to form inner cooling circulation loop;The pipeline of seawater pump water outlet is connected with the pipeline of heat exchanger water inlet by bypass with first bypass valve, the pipeline of fresh water pump water outlet is connected with the pipeline of engine water inlet by bypass with second bypass valve, temperature sensor is arranged at the outlet of intercooler, and engine control unit adjusts the opening of first bypass valve and second bypass valve according to different working conditions of engine;The application adopts seawater and fresh water double circulation grading cooling, in the case where guaranteeing cooling capacity, the reliability of intercooler can also be considered, and optimal intake temperature of engine is maintained under full working condition.

Description

Technical Field

[0001] This invention relates to the field of ship cooling control technology, and in particular to a closed-loop temperature regulation system and method for staged cooling of ship engines after intercooling. Background Technology

[0002] When an engine is working, it generates a lot of heat, causing the temperature of the engine block and related components to rise. When the temperature exceeds a certain value, it will affect the normal operation of the engine. The current marine engine system includes the engine, the air supply system and the cooling system. The air supply system includes the intercooler. The current marine engine intercooler uses a single cooling medium to cool the temperature of the pressurized gas.

[0003] Currently, seawater is commonly used to cool the pressurized air in the intercooler. However, seawater's low temperature leads to overcooling, failing to guarantee the engine's optimal operating temperature. Furthermore, seawater contains many impurities, and even with filtration before entering the intercooler, the impact of these impurities on the intercooler's reliability cannot be completely eliminated. Conversely, using freshwater to cool the intercooler requires a larger intercooler due to its higher inlet water temperature, resulting in space constraints and a less efficient cooling system. Additionally, current engine cooling systems are developed with the calibrated intercooler temperature as the control boundary to ensure cooling capacity under the most demanding conditions, but this fails to adjust the appropriate intercooler temperature for other engine operating conditions. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a closed-loop temperature regulation system and method for intercooler staged cooling of marine engines. This system employs dual-cycle staged cooling with both seawater and freshwater, ensuring cooling capacity while also maintaining the reliability of the intercooler and regulating the engine to maintain optimal intake air temperature under all operating conditions.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] In a first aspect, a closed-loop temperature regulation system for intercooler staged cooling of a marine engine includes a freshwater pump and a seawater pump. The seawater pump is connected to the intercooler and the heat exchanger in sequence through pipelines to form an external cooling loop. The freshwater pump is connected to the intercooler, the engine, and the heat exchanger in sequence through pipelines to form an internal cooling loop. The pipeline at the outlet of the seawater pump is connected to the inlet pipeline of the heat exchanger through a bypass with a first bypass valve. The pipeline at the outlet of the freshwater pump is connected to the inlet pipeline of the engine through a bypass with a second bypass valve. A temperature sensor is installed at the outlet of the intercooler. The engine control unit adjusts the opening of the first bypass valve and the second bypass valve according to different operating conditions of the engine.

[0007] As a further implementation, the air intake of the intercooler is connected to the turbocharger via a pipeline, and the engine control unit corrects the opening of the first bypass valve and the second bypass valve based on the temperature data fed back by the temperature sensor.

[0008] As a further implementation, one end of the bypass on the external cooling circulation loop is connected to the first bypass valve, and the other end is connected to a pipe near the first outlet of the intercooler to form a first bypass, through which an external cooling small circulation loop is formed.

[0009] As a further implementation, one end of the bypass on the internal cooling circulation loop is connected to a second bypass valve, and the other end is connected to a pipe near the second outlet of the intercooler to form a second bypass, thereby forming a small internal cooling circulation loop.

[0010] As a further implementation, both the first bypass valve and the second bypass valve are proportional three-way valves.

[0011] Secondly, a closed-loop control method for the temperature after intercooling in staged cooling of marine engines, employing a closed-loop temperature regulation system after intercooling, includes the following steps:

[0012] The optimal intercooler temperature is calibrated under various engine operating conditions, and the opening status of the corresponding first bypass valve and second bypass valve is input into the engine control unit to obtain the intercooler temperature MAP. Then, the engine control unit calls the MAP according to different engine operating conditions.

[0013] If the engine is in the first speed range, the engine control unit opens the first bypass valve and the second bypass valve to realize that the first bypass and the second bypass are in the open state, and the external cooling circulation loop and the internal cooling circulation loop do not participate in regulating the temperature after intercooling.

[0014] If the engine is in the second speed range, the engine control unit gradually adjusts the closing angle of the second bypass valve until it is fully closed, and participates in regulating the temperature after the intercooler through the internal cooling circulation loop.

[0015] If the engine is in the third speed range, the engine control unit gradually adjusts the closing angle of the first bypass valve until it is fully closed, and the external cooling circulation loop and the internal cooling circulation loop work together to regulate the temperature after intercooling.

[0016] As a further implementation, the engine control unit acquires the temperature data detected by the temperature sensor, compares it with the temperature MAP after intercooling, and then corrects the opening angles of the first bypass valve and the second bypass valve to achieve closed-loop control.

[0017] As a further implementation, while meeting the space requirements for the intercooler, the proportion of freshwater cooling can be increased to improve system reliability.

[0018] As a further implementation, when the external cooling circulation loop and the internal cooling circulation loop jointly participate in regulating the temperature after intercooling, the internal cooling circulation loop is given priority in participating in the regulation.

[0019] As a further implementation, the engine control unit corrects the opening angles of the first bypass valve and the second bypass valve by including the following steps:

[0020] If the temperature sensor detects a temperature higher than the set value, the engine control unit adjusts the opening of the first bypass valve and the second bypass valve to increase the flow of seawater and fresh water into the intercooler.

[0021] If the temperature sensor detects a temperature lower than the set value, the engine control unit adjusts the opening of the first bypass valve and the second bypass valve to reduce the flow of seawater and fresh water into the intercooler; during correction, the internal cooling circulation loop is used first for adjustment.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. In this invention, bypass valves are set up in both the external cooling circulation loop and the internal cooling circulation loop. The engine control unit can adjust the opening of the first bypass valve and the second bypass valve according to the different operating conditions of the engine, thereby realizing dual-cycle staged cooling of seawater and freshwater, ensuring cooling capacity while taking into account reliability and adjusting the engine to maintain the optimal intake air temperature under all operating conditions.

[0024] 2. This invention pre-calibrates the optimal intercooler temperature under various engine operating conditions and inputs the opening status of the corresponding first bypass valve and second bypass valve into the engine control unit to obtain an intercooler temperature MAP. The engine control unit can then call up the MAP according to different engine operating conditions.

[0025] 3. In this invention, a temperature sensor is installed at the outlet of the intercooler. The engine control unit makes MAP calls based on the engine operating conditions and corrects the settings based on the temperature value fed back by the temperature sensor after the intercooler, so as to ensure the optimal opening angle of the first bypass valve and the second bypass valve and realize closed-loop control.

[0026] 4. Since seawater temperature is lower than freshwater temperature, it has a better cooling effect at the same flow rate. Therefore, this invention prioritizes freshwater cooling, which can take into account the size of the intercooler and facilitate the overall layout. While meeting the space requirements for the intercooler layout, the proportion of freshwater cooling can be increased to improve system reliability. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0028] Figure 1 This is a schematic diagram of the overall structure of the closed-loop temperature regulation system after intercooling in the staged cooling of ship engines in this embodiment of the invention.

[0029] The diagram exaggerates the spacing or dimensions between parts to show their positions; the diagram is for illustrative purposes only.

[0030] Among them: 1. Engine, 2. Intercooler, 3. Heat exchanger, 4. Turbocharger, 5. Seawater pump, 6. Freshwater pump;

[0031] 21. Temperature sensor; 51. External cooling circulation loop; 52. First bypass valve; 61. Internal cooling circulation loop; 62. Second bypass valve. Detailed Implementation

[0032] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0033] Intercooler: Used to reduce the temperature of the boosted air, thereby reducing the engine's thermal load;

[0034] Calibration point: usually refers to the engine's rated power point, i.e., the maximum power point.

[0035] Example 1

[0036] In a typical embodiment of the present invention, reference is made to Figure 1 As shown, a closed-loop temperature regulation system for staged cooling of marine engines after intercooling includes an engine 1, an intercooler 2, a heat exchanger 3, a turbocharger 4, a seawater pump 5, and a freshwater pump 6.

[0037] The air inlet of intercooler 2 is connected to the turbocharger via a pipe. After being pressurized by turbocharger 4, the gas enters intercooler 2 and then enters the engine through the air outlet of intercooler 2. It can be understood that after the gas is pressurized by turbocharger 4, its pressure and temperature increase. Intercooler 2 cools the gas and increases its density, ensuring the efficiency of the subsequent engine 1 operation.

[0038] like Figure 1 As shown, the seawater pump 5 is connected to the intercooler 2 and the heat exchanger 3 in sequence through pipelines to form an external cooling circulation loop 51; the freshwater pump 6 is connected to the intercooler 2, the engine 1, and the heat exchanger 3 in sequence through pipelines to form an internal cooling circulation loop 61.

[0039] In this embodiment, the seawater pump 5 can pump seawater sequentially into the intercooler 2 and the heat exchanger 3, and the freshwater pump 6 can pump freshwater sequentially into the intercooler 2, the engine 1, and the heat exchanger 3. The seawater and freshwater entering the heat exchanger 3 exchange heat, improving the cooling effect of the freshwater on the engine 1. The seawater after heat exchange is discharged into the sea from the seawater outlet of the heat exchanger 3.

[0040] like Figure 1 As shown, the pipeline of the seawater pump 5 outlet is connected to the inlet pipeline of the heat exchanger 3 through a bypass with a first bypass valve 52. The pipeline of the external cooling circulation loop 51 enters the intercooler 2 through the first inlet of the intercooler 2 and extends out from the intercooler 2 through the first outlet of the intercooler 2 to connect to the heat exchanger 3.

[0041] In this embodiment, one end of the bypass on the external cooling circulation loop 15 is connected to the first bypass valve 52, and the other end is connected to a pipe near the first outlet of the intercooler 2, forming the first bypass on the external cooling circulation loop 51. The external cooling small circulation loop is formed through the first bypass. In this embodiment, the external cooling small circulation loop refers to the seawater pump 5, the first bypass, the heat exchanger 3, and the corresponding connecting pipes connected in sequence.

[0042] The pipeline from the outlet of the freshwater pump 6 is connected to the engine inlet pipeline via a bypass with a second bypass valve 62. The pipeline of the internal cooling circulation loop 61 enters the intercooler 2 through the second inlet of the intercooler and extends out from the intercooler 2 through the second outlet of the intercooler 2 to connect to the engine 1.

[0043] In this embodiment, one end of the bypass on the internal cooling circulation loop 61 is connected to the second bypass valve 62, and the other end is connected to a pipe near the second outlet of the intercooler 2, forming a second bypass on the internal cooling circulation loop 61. This second bypass forms a small internal cooling circulation loop. In this embodiment, the small internal cooling circulation loop refers to the freshwater pump 5, the second bypass, the engine 1, the heat exchanger 3, and the corresponding connecting pipes connected in sequence. The freshwater outlet of the heat exchanger 3 is connected to the inlet of the freshwater pump 6 via a pipe, forming a circulation loop.

[0044] In this embodiment, the engine control unit can adjust the opening of the first bypass valve 52 and the second bypass valve 62 according to different engine operating conditions. Both the first bypass valve 52 and the second bypass valve 62 are proportional three-way valves.

[0045] Specifically, before the system is applied, the opening degree of the first bypass valve 52 and the second bypass valve 62 is adjusted under different engine speeds and load conditions. Under the premise of meeting emission limits and based on the principle of minimizing engine fuel consumption, the optimal intercooler temperature of the engine under each operating condition is calibrated. The opening degree of the corresponding first bypass valve 52 and the second bypass valve 62 is then input into the engine control unit to obtain the intercooler temperature MAP. After that, the engine control unit can call up the MAP according to different engine operating conditions.

[0046] Considering the difference between the calibrated temperature MAP after the intercooler and the ambient temperature during actual engine system operation, a temperature sensor 21 is installed at the outlet of the intercooler 2. The engine control unit calls up the MAP according to the engine operating conditions and corrects the temperature value fed back by the temperature sensor 21 after the intercooler, which can realize closed-loop control and ensure the optimal opening angle of the first bypass valve 52 and the second bypass valve 62. At the same time, it can also solve the problem of opening angle deviation caused by mechanical wear due to prolonged valve use.

[0047] If engine 1 is in the first speed range, the engine control unit opens the first bypass valve and the second bypass valve to achieve the first bypass and the second bypass being in the open state. At this time, the external cooling circulation loop 51 and the internal cooling circulation loop 61 do not participate in regulating the temperature after intercooling; that is, neither fresh water nor seawater enters the intercooler 2 to cool the gas. The first speed range is the engine idling speed and low load condition. At this time, the temperature of the gas after boosting is already low and does not need to be cooled, which can reduce the risk of engine 1 emitting white smoke.

[0048] If engine 1 is in the second speed range, the engine control unit gradually adjusts the closing angle of the second bypass valve until it is fully closed. Fresh water in the internal cooling circulation loop participates in regulating the temperature after intercooling, while the first bypass on the external cooling circulation loop remains open, preventing seawater from entering intercooler 2 to participate in regulating the temperature after intercooling and ensuring the reliability of the intercooler. The second speed range is medium speed and medium load.

[0049] If engine 1 is in the third speed range, the engine control unit gradually adjusts the closing angle of the first bypass valve 52 until it is fully closed, and the external cooling circulation loop 51 and the internal cooling circulation loop 61 work together to regulate the temperature after intercooling.

[0050] Example 2

[0051] A closed-loop control method for the temperature after intercooling in staged cooling of marine engines, employing a closed-loop temperature regulation system after intercooling, includes the following steps:

[0052] Before the application of this system, the optimal intercooler temperature of the engine under different speeds and load conditions was calibrated by adjusting the opening degree of the first bypass valve 52 and the second bypass valve 62, based on the principle of minimizing engine fuel consumption, while meeting emission limits. The opening degree of the corresponding first bypass valve 52 and the second bypass valve 62 was then input into the engine control unit to obtain the intercooler temperature MAP. The engine control unit can then call up the MAP according to different engine operating conditions.

[0053] If engine 1 is in the first speed range, which is the engine 1 idling speed and low load condition, the engine control unit opens the first bypass valve 52 and the second bypass valve 62 to realize that the first bypass and the second bypass are in the open state. The seawater in the external cooling circulation loop 51 and the fresh water in the internal cooling circulation loop 61 do not enter the intercooler 2 and do not participate in regulating the temperature after intercooling, thereby reducing the risk of engine 1 emitting white smoke.

[0054] As the engine speed increases, if the engine is in the second speed range, which is the medium speed and medium load condition of the engine, when the air temperature entering the intercooler 2 needs to be cooled, the internal cooling circulation loop 61 is controlled first, and the engine control unit gradually adjusts the closing angle of the second bypass valve 62 until it is fully closed, and participates in the regulation of the temperature after intercooling through the internal cooling circulation loop 61.

[0055] Within this speed range, as the engine speed increases, the second bypass controlled by the second bypass valve 62 is gradually closed until it is completely closed. After the second bypass is completely closed, the internal cooling circulation loop 61 is fully involved in regulating the temperature after intercooling. Cooling is achieved using fresh water, which contains fewer impurities than seawater, effectively improving the maintenance cycle and service life of the intercooler.

[0056] In the second speed range, engine 1 can basically meet the cooling requirements by relying on fresh water cooling. However, as the gas temperature increases further after pressurization, engine 1 is in the third speed range: high speed and high load conditions. At this time, relying solely on fresh water cooling cannot meet the cooling requirements, and seawater cooling needs to be introduced.

[0057] The engine control unit gradually adjusts the closing angle of the first bypass valve 52 until it is fully closed, and the external cooling circulation loop 51 and the internal cooling circulation loop 61 work together to regulate the temperature after intercooling. During this process, the amount of seawater entering the intercooler from the external cooling circulation loop increases, and the cooling efficiency gradually improves. Because the seawater temperature is lower than the freshwater temperature, it has a better cooling effect at the same flow rate, which can take into account the size of the intercooler and facilitate the overall layout of the engine.

[0058] Therefore, in this embodiment, seawater is only controlled to participate in cooling when the engine 1 is at high speed and high load, which can effectively improve the maintenance cycle and service life of the intercooler.

[0059] Considering the differences between the calibrated temperature map after the intercooler and the ambient temperature during actual engine system operation, a temperature sensor is installed at the intercooler outlet. The engine control unit (ECU) calls up the MAP based on engine operating conditions and corrects the settings using the temperature value fed back from the intercooler temperature sensor. The ECU obtains the temperature data detected by the temperature sensor and compares it with the intercooler temperature map to correct the opening angles of the first and second bypass valves, thus achieving closed-loop control and ensuring the optimal opening angles of the first and second bypass valves. This also solves the problem of opening angle deviation caused by mechanical wear due to prolonged valve use.

[0060] The intercooling temperature MAP in this embodiment Figure 1 Generally calibrated under standard conditions (intake air temperature 25℃, atmospheric pressure 100kPa, relative humidity 30%), when the actual operating environment of the engine deviates from the standard environment, the valve opening set according to the original MAP (Magnetic Mapping Specification) may not be able to meet the cooling requirements of the boosted gas temperature. In this case, based on real-time data detected by the temperature sensor, the engine control unit determines that if the temperature deviation from the calibration is large, it will correct the valve opening.

[0061] Specifically, the engine control unit corrects the opening angles of the first bypass valve and the second bypass valve through the following steps:

[0062] If the temperature sensor detects a temperature higher than the set value (calibrated temperature), the engine control unit adjusts the opening of the first bypass valve and the second bypass valve to increase the flow of seawater and fresh water into the intercooler.

[0063] If the temperature sensor detects a temperature lower than the set value (calibrated temperature), the engine control unit adjusts the opening of the first bypass valve and the second bypass valve to reduce the flow of seawater and fresh water into the intercooler; during correction, the internal cooling circulation loop is used first to participate in the adjustment.

[0064] If the temperature sensor detects a temperature that is close to the calibrated temperature, the engine control unit continues to operate based on the temperature MAP after the intercooler.

[0065] It is understandable that when the external cooling circulation loop 51 and the internal cooling circulation loop 61 jointly participate in regulating the temperature after intercooling, the internal cooling circulation loop 61 is given priority in participating in the regulation. Under the condition of satisfying the space arrangement of the intercooler, this embodiment can increase the proportion of fresh water cooling to improve system reliability.

[0066] This embodiment achieves dual-cycle staged cooling using both seawater and freshwater, ensuring both cooling capacity and reliability. Simultaneously, a pre-calibrated MAP is performed, and closed-loop control is adopted to adjust the appropriate intercooler temperature according to different engine operating conditions.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A closed-loop temperature control method for intercooler staged cooling of marine engines, characterized in that, A closed-loop temperature control system for intercooler staged cooling of marine engines is adopted, including a freshwater pump and a seawater pump. The seawater pump is connected to the intercooler and heat exchanger in sequence through pipelines to form an external cooling loop, and the freshwater pump is connected to the intercooler, engine and heat exchanger in sequence through pipelines to form an internal cooling loop. The pipeline at the outlet of the seawater pump is connected to the inlet pipeline of the heat exchanger through a bypass with a first bypass valve, and the pipeline at the outlet of the freshwater pump is connected to the inlet pipeline of the engine through a bypass with a second bypass valve. A temperature sensor is installed at the outlet of the intercooler, and the engine control unit adjusts the opening of the first bypass valve and the second bypass valve according to different operating conditions of the engine. The optimal intercooler temperature is calibrated under various engine operating conditions, and the opening status of the corresponding first bypass valve and second bypass valve is input into the engine control unit to obtain the intercooler temperature MAP. Then, the engine control unit calls the MAP according to different engine operating conditions. If the engine is in the first speed range, the engine control unit opens the first bypass valve and the second bypass valve to make the first bypass and the second bypass open, and the external cooling circulation loop and the internal cooling circulation loop do not participate in regulating the temperature after intercooling. If the engine is in the second speed range, the engine control unit gradually adjusts the closing angle of the second bypass valve until it is fully closed, and participates in regulating the temperature after the intercooler through the internal cooling circulation loop; If the engine is in the third speed range, the engine control unit gradually adjusts the closing angle of the first bypass valve until it is fully closed, and the external cooling circulation loop and the internal cooling circulation loop work together to regulate the temperature after the intercooler. The engine control unit acquires the temperature data detected by the temperature sensor, compares it with the temperature MAP after intercooling, and then corrects the opening angles of the first bypass valve and the second bypass valve to achieve closed-loop control. The engine control unit corrects the opening angles of the first bypass valve and the second bypass valve through the following steps: If the temperature sensor detects a temperature higher than the set value, the engine control unit adjusts the opening of the first bypass valve and the second bypass valve to increase the flow of seawater and fresh water into the intercooler. If the temperature sensor detects a temperature lower than the set value, the engine control unit adjusts the opening of the first bypass valve and the second bypass valve to reduce the flow of seawater and fresh water into the intercooler; during correction, the internal cooling circulation loop is used first for adjustment.

2. The closed-loop temperature control method after intercooling in staged cooling of marine engines according to claim 1, characterized in that, The air intake of the intercooler is connected to the turbocharger via a pipeline, and the engine control unit adjusts the opening of the first bypass valve and the second bypass valve based on the temperature data fed back by the temperature sensor.

3. The closed-loop temperature control method after intercooling in staged cooling of marine engines according to claim 1, characterized in that, One end of the bypass on the external cooling circulation loop is connected to the first bypass valve, and the other end is connected to the pipe near the first outlet of the intercooler to form the first bypass, and the external cooling small circulation loop is formed through the first bypass.

4. The closed-loop temperature control method after intercooling in staged cooling of marine engines according to claim 1, characterized in that, One end of the bypass on the internal cooling circulation loop is connected to the second bypass valve, and the other end is connected to the pipe near the second outlet of the intercooler to form a second bypass, which forms a small internal cooling circulation loop.

5. The closed-loop temperature control method after intercooling in staged cooling of marine engines according to claim 1, characterized in that, Both the first bypass valve and the second bypass valve are proportional three-way valves.

6. The closed-loop temperature control method after intercooling in staged cooling of marine engines according to claim 1, characterized in that, While ensuring sufficient space for the intercooler, the proportion of freshwater cooling is increased to improve system reliability.

7. The closed-loop temperature control method after intercooling in staged cooling of marine engines according to claim 1, characterized in that, When both the external cooling circulation loop and the internal cooling circulation loop work together to regulate the temperature after intercooling, the internal cooling circulation loop should be used preferentially for regulation.

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