A system and method for controlling the generation of acidic condensate in an exhaust gas recirculation system

Abstract

The present application provides a system for controlling the generation of acidic condensate in an exhaust gas recirculation system, comprising an air cooler, a three-way valve, a heater, a pH meter, a temperature sensor, a dew point meter, and a neutralization unit. Cooling fresh water flows within the air cooler, and a three-way valve is provided between the cooling fresh water inlet and outlet, and the air cooler, for regulating the flow of cooling fresh water at the inlet. A controller is communicatively connected to the pH meter, heater, temperature sensor, dew point meter, neutralization unit, and exhaust gas recirculation system, and is configured to collect communication signals, including the pH value monitored by the pH meter, the temperature value T07 monitored by the temperature sensor, the dew point value T08 monitored by the dew point meter, and the required temperature T of the pressurized gas transmitted from the exhaust gas recirculation system, and to control the operating states of the three-way valve, heater, and neutralization unit based on the communication signals. This system effectively reduces the generation of acidic condensate and mitigates the negative impact on ship design.

Description

Technical Field

[0001] The present application relates to the field of exhaust gas cleaning technology, and in particular to a system and method for controlling the generation of acidic condensate in an exhaust gas recirculation system. Background Art

[0002] In 2018, the International Maritime Organization (IMO) proposed a preliminary phased strategy for greenhouse gas emissions reduction, specifying a target of at least a 50% reduction in greenhouse gas emissions from the international shipping industry by 2050. Currently, the Otto cycle is commonly used in LNG-fueled ship engines. However, this technology has a fundamental flaw: methane slip. Methane, another greenhouse gas dozens of times more potent than CO2, contributes even more significantly to the global warming effect. To address this issue and alleviate shipowners' concerns, WinGD has introduced the intelligent exhaust gas recirculation (iCER) system. While this system addresses the aforementioned methane slip problem, it introduces new challenges. When exhaust gas is introduced into the exhaust gas recirculation system, water vapor in the charge air must be cooled by low-temperature fresh water and condensed. This condensed water inevitably absorbs sulfur oxides that remain in the exhaust gas. Furthermore, when part of the main engine exhaust gas is recirculated into the main engine air system, a certain amount of acidic condensate is inevitably generated. This acidic condensate has impacted the design of both the iCER system's main engine and the vessel's systems. For example, the main engine requires the use of acid-resistant stainless steel air coolers, increasing vessel construction costs. Furthermore, the acidic condensate must be regularly discharged into the system for disposal, a cumbersome process that increases safety risks. Summary of the Invention

[0003] The purpose of the embodiments of the present application is to provide a system and method for controlling the generation of acidic condensed water in an exhaust gas recirculation system. The system controls the generation of acidic condensed water in the exhaust gas recirculation system by real-time monitoring of the temperature in the air cooler and controlling the working status of the three-way valve, heater and neutralization unit, thereby solving the above-mentioned problem.

[0004] In a first aspect, a system for controlling the generation of acidic condensate in an exhaust gas recirculation system is provided, comprising:

[0005] An air cooler, the air cooler comprising a gas inlet and a gas outlet. After being cleaned and pressurized to become pressurized gas, the exhaust gas enters the air cooler through the gas inlet. Cooling fresh water flows in the air cooler. A three-way valve is provided between the cooling fresh water inlet, the cooling fresh water outlet, and the air cooler to regulate the flow of the cooling fresh water at the water inlet. The pressurized gas entering the air cooler is cooled by the cooling fresh water and then discharged from the gas outlet.

[0006] a heater, arranged on the air cooler, for heating the cooling fresh water in the air cooler;

[0007] a pH meter, arranged in the air cooler, for monitoring the pH value of the pressurized air;

[0008] a temperature sensor, arranged at a gas outlet side of the air cooler, for monitoring the temperature of the cooled charge air;

[0009] a dew point detector, arranged at the gas outlet side of the air cooler, for monitoring the dew point of the cooled charge air;

[0010] a neutralization unit, connected to the air cooler through a pipeline, and used for delivering neutralization liquid into the air cooler in real time;

[0011] The controller is communicatively connected to the pH meter, heater, temperature sensor, dew point detector, neutralization unit, and exhaust gas recirculation system, and is used to collect communication signals, wherein the communication signals include the pH value monitored by the pH meter, the temperature value T07 monitored by the temperature sensor, the dew point value T08 monitored by the dew point detector, and the required temperature T of the pressurized gas transmitted from the exhaust gas recirculation system, and controls the operating status of the three-way valve, heater, and neutralization unit by comparing the temperature value T07, the dew point value T08, and the required temperature T of the pressurized gas.

[0012] In one embodiment, the three-way valve includes two working states. When the three-way valve is in a closed state with an opening degree of 0%, cooling fresh water enters from the water inlet and flows directly into the air cooler through the three-way valve; when the three-way valve is in an open state with an opening degree of 100%, the water inlet is isolated from the air cooler, and the cooling fresh water flowing out of the air cooler flows back to the air cooler through the three-way valve.

[0013] In one embodiment, when the controller determines that T07 ≥ T ≥ T08, the controller controls the three-way valve, the heater, and the neutralization unit to be in a closed state;

[0014] When the controller determines that T08≤T07<T, the controller controls the three-way valve to gradually increase the opening from the closed state of 0% opening until T07=T. If the three-way valve increases the opening to the open state of 100% and T07 is still less than T, the controller starts the heater to enter the working state until T07=T.

[0015] When the controller determines that T07<T08<T, the controller controls the three-way valve to gradually increase the opening from the closed state of 0% opening until T07=T. If the three-way valve increases the opening to the open state of 100%, T07 is still less than T, and the controller starts the heater to enter the working state until T07=T. During the adjustment process, when T07 gradually approaches T08, the controller controls the neutralization unit to operate according to the pH value, so that the pH value of the condensed water in the air cooler is greater than or equal to 6.5.

[0016] In one embodiment, when the controller determines that T07 ≥ T08 ≥ T, the controller controls the three-way valve, the heater, and the neutralization unit to be in a closed state;

[0017] When the controller determines that T08>T07≥T+n, the controller controls the three-way valve to be in a closed state with an opening degree of 0%, and controls the operation of the neutralization unit according to the pH value to make the pH value of the condensed water in the air cooler greater than or equal to 6.5, where T+n is the maximum critical value for the normal operation of the exhaust gas recirculation system host, and n is a positive number;

[0018] When the controller determines that T08>T+n>T07, the controller controls the three-way valve to gradually increase its opening from a closed state of 0% opening until T07=T+n. If the three-way valve increases its opening to an open state of 100% and T07 is still less than T+n, the controller starts the heater to enter a working state until T07=T+n. During the adjustment process, when T07 gradually approaches T08, the controller controls the neutralization unit to operate according to the pH value, so that the pH value of the condensed water in the air cooler is greater than or equal to 6.5.

[0019] When the controller determines that T+n>T08>T, and T07≥T08, the controller controls the three-way valve, the heater and the neutralization unit to be in a closed state;

[0020] When the controller determines that T+n>T08>T, and T08>T07, the controller controls the three-way valve to gradually increase the opening from the closed state of 0% opening until T07=T08. If the three-way valve increases the opening to the open state of 100%, T07 is still less than T08, and the controller starts the heater to enter the working state until T07=T08. During the adjustment process, when T07 gradually approaches T08, the controller controls the neutralization unit to operate according to the pH value, so that the pH value of the condensed water in the air cooler is greater than or equal to 6.5, and reaches a stable state of T07=T08.

[0021] In one embodiment, the neutralization unit comprises a nozzle arranged at the end of the pipeline, and the nozzle is arranged above the interior of the air cooler for spraying neutralization liquid into the air cooler in real time.

[0022] In one embodiment, a liquid level meter is further included. The liquid level meter is arranged at a preset height from the inner bottom of the air cooler and is used to monitor the height of condensed water in the air cooler.

[0023] In one embodiment, a fresh water pump is further included, and the fresh water pump is located between the three-way valve and the air cooler, and is used to provide fresh water to enter the air cooler.

[0024] In one embodiment, the heater is arranged between the air cooler and the outlet of the cooling fresh water. When the three-way valve is in an open state with an opening degree of 100%, the cooling fresh water flowing out of the air cooler flows through the heater and is heated. The heated cooling fresh water then flows back to the air cooler through the three-way valve.

[0025] According to a second aspect of the present application, a method for controlling the generation of acidic condensed water in an exhaust gas recirculation system is also provided, comprising:

[0026] Real-time monitoring of the temperature of the charge air at the gas outlet side of the air cooler;

[0027] Real-time monitoring of the dew point value of the pressurized air at the gas outlet side of the air cooler;

[0028] Real-time monitoring of the pH value of the charge air in the air cooler;

[0029] By comparing the temperature value of the pressurized air, the dew point value of the pressurized air and the required temperature of the pressurized gas, the flow rate and temperature of the cooling fresh water entering the air cooler are controlled, and neutralizing liquid is delivered to the air cooler in real time to adjust the pH value of the pressurized air.

[0030] This application has the following beneficial effects:

[0031] This application installs a pH meter, temperature sensor, dew point meter, three-way valve, heater, and neutralization unit on the air cooler. By adjusting and controlling the collected communication signals in real time, it can effectively reduce the generation of acidic condensate from the main engine and mitigate the negative impact on ship design. This reduces the cost of the main engine and the impact on ship system design, thereby reducing the cost of ship construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 Schematic diagram of a system for controlling the generation of acidic condensed water in an exhaust gas recirculation system according to an embodiment of the present application;

[0034] Figure 2 Schematic diagram of the connection between a system for controlling the generation of acidic condensed water in an exhaust gas recirculation system and the exhaust gas recirculation system according to an embodiment of the present application.

[0035] 10. Main engine exhaust manifold; 20. Compressor; 30. Scrubber; 40. Circulation tank; 50. Blower; 60. Scavenging air box; 100. Air cooler; 110. Gas inlet; 111. Exhaust gas; 112. Clean exhaust gas; 113. Fresh air; 114. Pressurized gas; 120. Gas outlet; 210. Water inlet; 220. Water outlet; 300. Three-way valve; 310. Fresh water pump; 400. Heater; 500. pH meter; 510. Liquid level gauge; 600. Temperature sensor; 700. Dew point detector; 800. Neutralization unit; 810. Pipeline; 820. Nozzle; 900. Controller. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0038] In a first aspect, the present application provides a system for controlling the generation of acidic condensate in an exhaust gas recirculation system. Figure 1 FIG is a structural diagram of a system for controlling the generation of acidic condensed water in an exhaust gas recirculation system according to an embodiment of the present application. Figure 1The system includes an air cooler, a heater, a pH meter, a temperature sensor, a dew point detector, a neutralization unit and a controller.

[0039] The air cooler 100 includes a gas inlet 110 and a gas outlet 120. After the exhaust gas is cleaned and pressurized to become pressurized gas, it enters the air cooler 100 from the gas inlet 110. Figure 2 Specifically, the exhaust gas recirculation system includes an engine exhaust manifold 10, a compressor 20, a scrubber 30, a circulation tank 40, a blower 50, and a scavenge air box 60. Exhaust gas 111 enters the exhaust gas recirculation system from the engine exhaust manifold 10, is converted into clean exhaust gas 112 by the scrubber 30 and circulation tank 40, and then enters the compressor 20. The compressor 20 pressurizes the clean exhaust gas 112 and fresh air 113 into pressurized gas 114, which is then fed into the air cooler 100 through the gas inlet 110. Cooling fresh water flows through the air cooler 100. A three-way valve 300 is installed between the cooling fresh water inlet 210, the water outlet 220, and the air cooler 100 to adjust the flow rate of the cooling fresh water at the water inlet 210. The pressurized gas entering the air cooler 100 is cooled by the cooling fresh water and then discharged through the gas outlet 120. The gas outlet 120 of the air cooler 100 is connected to the scavenge air box 60.

[0040] The heater 400 is arranged on the cooling fresh water pipeline of the air cooler 100 and is used to heat the cooling fresh water in the air cooler 100;

[0041] The pH meter 500 is arranged in the air cooler 100 and is used to monitor the pH value of the charge air;

[0042] The temperature sensor 600 is arranged on the gas outlet 120 side of the air cooler 100 to monitor the temperature of the cooled charge air;

[0043] The dew point detector 700 is arranged on the gas outlet 120 side of the air cooler 100 and is used to monitor the dew point of the cooled charge air;

[0044] The neutralization unit 800 is connected to the air cooler 100 via a pipe 810 for delivering the neutralization liquid into the air cooler 100 in real time;

[0045] The controller 900 is communicatively connected to the heater 400, the pH meter 500, the temperature sensor 600, the dew point detector 700, the neutralization unit 800 and the exhaust gas recirculation system for collecting communication signals, which include the pH value monitored by the pH meter 500, the temperature value T07 monitored by the temperature sensor 600, the dew point value T08 monitored by the dew point detector 700, and the required temperature T of the pressurized gas transmitted from the exhaust gas recirculation system, and controls the working status of the three-way valve 300, the heater 400 and the neutralization unit 800 by comparing the temperature value T07, the dew point value T08 and the required temperature T of the pressurized gas.

[0046] In the above implementation process, this system, by deploying a series of devices within the air cooler where acidic condensate is generated, enables real-time monitoring and control of acidic condensate generation during the operation of the exhaust gas recirculation system. This effectively reduces the generation of acidic condensate and its negative impact on ship design, lowering ship construction costs and making the exhaust gas recirculation system safer and more efficient.

[0047] In one embodiment, the three-way valve 300 has two operating states. When the three-way valve 300 is in the closed state (0% opening), cooling water enters the water inlet 210 and flows directly into the air cooler 100 through the three-way valve 300, indicating that the b and a of the three-way valve 300 are connected. When the three-way valve 300 is in the open state (100% opening), the water inlet 210 is isolated from the air cooler 100, and the cooling water flowing out of the air cooler 100 flows back into the air cooler 100 through the three-way valve 300, indicating that the c and a of the three-way valve 300 are connected. By placing the three-way valve 300 between the cooling water inlet 210, the water outlet 220, and the air cooler 100, and controlling the operating state of the three-way valve 300, the temperature of the cooling water in the air cooler 100 can be regulated. Controlling the cooling water temperature can further control the generation of acidic condensate and the normal operation of the exhaust gas recirculation system.

[0048] Next, we will detail the specific control process of controller 900. When the entire system is operational, controller 900 first receives an operating signal from the exhaust gas recirculation (EGR) host system via interface ①. It then performs control based on the collected communication signals. These signals include the pH value monitored by pH meter 500, the temperature value T07 monitored by temperature sensor 600, the dew point value T08 monitored by dew point meter 700, and the required pressurized gas temperature T transmitted from the EGR system.

[0049] When T≥T08, the controller 900 determines the magnitude relationship between T and T07 and takes corresponding actions:

[0050] In one embodiment, when controller 900 determines that T07 ≥ T08, water vapor in the pressurized air will not precipitate because T07 ≥ T08. That is, no host-derived acidic condensate is generated in air cooler 100. Controller 900 controls three-way valve 300, heater 400, and neutralization unit 800 to be closed. That is, three-way valve 300 remains stationary, in a default operating state.

[0051] When controller 900 determines that T08 ≤ T07 < T, the pressurized air outlet temperature is lower than the required pressurized air temperature (T), impacting engine performance. Controller 900 controls three-way valve 300 to gradually increase its opening from 0% closed until T07 = T. If T07 is still less than T after three-way valve 300 reaches 100% open, controller 900 activates heater 400 until T07 = T. During this adjustment process and after reaching a stable state, water vapor in the pressurized air is prevented from precipitating when T07 ≥ T08, meaning no engine-derived acidic condensate is generated within air cooler 100.

[0052] If controller 900 determines that T07 < T08 < T, the charge air outlet temperature is lower than the required temperature for the main engine, impacting main engine performance. Controller 900 controls three-way valve 300 to gradually increase its opening from 0% closed until T07 = T. If T07 is still less than T after three-way valve 300 is opened to 100%, controller 900 activates heater 400 until T07 = T. During the adjustment process, as T07 approaches T08, condensate will form. Controller 900 controls the neutralization unit based on the pH value collected by pH meter 500, maintaining the pH of the condensate in air cooler 100 at a value greater than or equal to 6.5. Once T07 moves away from T08, meaning T07 > T08, no further condensate will form.

[0053] When T<T08, the controller 900 determines the relationship between T, T08 and T07 and takes corresponding actions:

[0054] In one embodiment, when the controller 900 determines that T07≥T08≥T, the controller 900 controls the three-way valve 300, the heater 400 and the neutralization unit 800 to be in a closed state, that is, the three-way valve 300 remains stationary and is in a default working state. At this time, no host condensate water will be generated.

[0055] When the controller 900 determines that T08>T07≥T+n, in order to prioritize the operating performance of the main engine, the controller 900 controls the three-way valve 300 to be in a closed state with an opening of 0%, that is, the three-way valve 300 remains stationary and is in the default operating state. The controller 900 controls the operation of the neutralization unit 800 according to the pH value, so that the pH value of the condensed water in the air cooler 100 is greater than or equal to 6.5. Among them, T+n is the maximum critical value for the normal operation of the exhaust gas recirculation system main engine, and n is a positive number; n can be determined according to the actual operating conditions. In one feasible case, it can be set to a value of 5. By taking a maximum critical value for comparison, the present application can control the generation of acidic condensed water to the greatest extent while ensuring the operating performance of the main engine.

[0056] When the controller 900 determines that T08 > T+n > T07, to ensure engine performance while minimizing condensate generation, the controller 900 controls the three-way valve 300 to gradually increase its opening from 0% closed until T07 = T+n. If T07 is still less than T+n after the three-way valve 300 is opened to 100%, the controller 900 activates the heater 400 and puts it into operation until T07 = T+n. During this adjustment process and after reaching a stable state, water vapor in the pressurized air will precipitate, generating condensate. As T07 approaches T08, the controller 900 controls the neutralization unit based on the pH value, maintaining the pH of the condensate in the air cooler 100 at a value greater than or equal to 6.5.

[0057] If controller 900 determines that T+n>T08>T and T07≥T08, it prioritizes reducing condensate generation. Controller 900 controls three-way valve 300, heater 400, and neutralization unit 800 to be closed. In other words, three-way valve 300 remains in its default operating state, preventing the host from generating condensate.

[0058] When controller 900 determines that T+n>T08>T, and T08>T07, it prioritizes reducing condensate production. Controller 900 controls three-way valve 300 to gradually increase its opening from 0% closed until T07=T08. If three-way valve 300 increases to 100% open and T07 is still less than T08, controller 900 activates heater 400 and puts it into operation until T07=T08. During the regulation process, water vapor in the pressurized air will precipitate, generating engine condensate. As T07 approaches T08, controller 900 controls the neutralization unit based on the pH value, maintaining the pH of the condensate in air cooler 100 at or above 6.5. This stabilizes the condensate, i.e., T07=T08, and no further condensate is produced.

[0059] In the above implementation, by determining the relationship between the temperature value T07 monitored by the temperature sensor 600, the dew point value T08 monitored by the dew point detector 700, and the required temperature T of the pressurized gas transmitted by the exhaust gas recirculation system, the generation of acidic condensate is minimized while ensuring the operation of the main engine. This achieves control of the condensate generated during the operation of the exhaust gas recirculation system.

[0060] In one embodiment, the neutralization unit 800 includes a nozzle 820 disposed at the end of a pipe 810. The nozzle 820 is positioned above the interior of the air cooler 100 and is used to spray neutralizing liquid into the air cooler 100 in real time. Using a single nozzle and positioning the nozzle from above for spraying can fully neutralize the acidic condensate within the air cooler. Furthermore, the cooling water device within the air cooler generally utilizes a mesh structure, which can reduce the impact of condensate on the air cooler's internal devices and avoid clogging of the mesh structure.

[0061] In one embodiment, a liquid level gauge 510 is also included. Liquid level gauge 510 is located at a predetermined height from the inner bottom of the air cooler 100 and is used to monitor the level of condensed water within the air cooler 100. This placement of liquid level gauge 510 allows for the timely discharge of neutralized condensed water from the air cooler when it reaches a predetermined level. Due to the use of a neutralizing liquid, the condensed water can be stored and discharged only after reaching a predetermined level, reducing the frequency of discharge and the number of discharge steps.

[0062] In one embodiment, a fresh water pump 310 is further included. The fresh water pump 310 is located between the three-way valve 300 and the air cooler 100 and is used to provide fresh water to the air cooler 100. The fresh water pump 310 is generally in a normal operating state. Accordingly, the three-way valve 300 defaults to a closed state with an opening of 0%.

[0063] In one embodiment, heater 400 is positioned between air cooler 100 and cooling water outlet 220. When three-way valve 300 is 100% open, the cooling water flowing out of air cooler 100 is heated by heater 400 and then flows back through three-way valve 300 to air cooler 100. This application utilizes heater 400 positioned in the cooling water discharge line, cleverly utilizing three-way valve 300 and strategically arranging the position to heat the cooling water even when the three-way valve 300 is open. This reduces the need for centralized placement on a single pipeline, which would be inconvenient for subsequent equipment maintenance. Furthermore, it avoids the performance instability associated with placement of heater 400 in the cooling water inlet line.

[0064] In a second aspect, the present application further provides a method for controlling the generation of acidic condensed water in an exhaust gas recirculation system, comprising:

[0065] Real-time monitoring of the temperature of the charge air at the gas outlet side of the air cooler;

[0066] Real-time monitoring of the dew point value of the pressurized air at the gas outlet side of the air cooler;

[0067] Real-time monitoring of the pH value of the charge air in the air cooler;

[0068] By comparing the temperature value of the pressurized air, the dew point value of the pressurized air and the required temperature of the pressurized gas, the flow rate and temperature of the cooling fresh water entering the air cooler are controlled, and neutralizing liquid is delivered to the air cooler in real time to adjust the pH value of the pressurized air.

[0069] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A system for controlling the generation of acidic condensate in an exhaust gas recirculation system, characterized in that: include: An air cooler, the air cooler comprising a gas inlet and a gas outlet, wherein the exhaust gas, after being cleaned and pressurized to become pressurized gas, enters the air cooler from the gas inlet; Cooling fresh water flows in the air cooler, and a three-way valve is provided between the cooling fresh water inlet, the cooling fresh water outlet and the air cooler to adjust the cooling fresh water flow at the water inlet; The pressurized gas entering the air cooler is cooled by the cooling fresh water and then discharged from the gas outlet; a heater, arranged on the air cooler, for heating the cooling fresh water in the air cooler; a pH meter, arranged in the air cooler, for monitoring the pH value of the pressurized air; a temperature sensor, arranged at a gas outlet side of the air cooler, for monitoring the temperature of the cooled charge air; a dew point detector, arranged at the gas outlet side of the air cooler, for monitoring the dew point of the cooled charge air; a neutralization unit, connected to the air cooler through a pipeline, and used for delivering neutralization liquid into the air cooler in real time; The controller is communicatively connected to the pH meter, heater, temperature sensor, dew point detector, neutralization unit, and exhaust gas recirculation system, and is used to collect communication signals, wherein the communication signals include the pH value monitored by the pH meter, the temperature value T07 monitored by the temperature sensor, the dew point value T08 monitored by the dew point detector, and the required temperature T of the pressurized gas transmitted from the exhaust gas recirculation system, and controls the operating status of the three-way valve, heater, and neutralization unit by comparing the temperature value T07, the dew point value T08, and the required temperature T of the pressurized gas.

2. The system for controlling the generation of acidic condensed water in an exhaust gas recirculation system according to claim 1, characterized in that: The three-way valve includes two working states. When the three-way valve is in a closed state with an opening degree of 0%, cooling fresh water enters from the water inlet and flows directly into the air cooler through the three-way valve; when the three-way valve is in an open state with an opening degree of 100%, the water inlet is isolated from the air cooler, and the cooling fresh water flowing out of the air cooler flows back to the air cooler through the three-way valve.

3. The system for controlling the generation of acidic condensed water in an exhaust gas recirculation system according to claim 2, characterized in that: When the controller determines that T07 ≥ T ≥ T08, the controller controls the three-way valve, the heater and the neutralization unit to be in a closed state; When the controller determines that T08≤T07<T, the controller controls the three-way valve to gradually increase the opening from the closed state of 0% opening until T07=T. If the three-way valve increases the opening to the open state of 100% and T07 is still less than T, the controller starts the heater to enter the working state until T07=T. When the controller determines that T07<T08<T, the controller controls the three-way valve to gradually increase the opening from the closed state of 0% opening until T07=T. If the three-way valve increases the opening to the open state of 100%, T07 is still less than T, the controller starts the heater to enter the working state until T07=T; during the adjustment process, when T07 gradually approaches T08, the controller controls the neutralization unit to operate according to the pH value, so that the pH value of the condensed water in the air cooler is greater than or equal to 6.

5.

4. The system for controlling the generation of acidic condensed water in an exhaust gas recirculation system according to claim 2, characterized in that: When the controller determines that T07 ≥ T08 ≥ T, the controller controls the three-way valve, the heater and the neutralization unit to be in a closed state; When the controller determines that T08>T07≥T+n, the controller controls the three-way valve to be in a closed state with an opening degree of 0%, and controls the operation of the neutralization unit according to the pH value to make the pH value of the condensed water in the air cooler greater than or equal to 6.5, where T+n is the maximum critical value for the normal operation of the exhaust gas recirculation system host, and n is a positive number; When the controller determines that T08>T+n>T07, the controller controls the three-way valve to gradually increase its opening from a closed state of 0% opening until T07=T+n. If the three-way valve increases its opening to an open state of 100% and T07 is still less than T+n, the controller starts the heater to enter a working state until T07=T+n. During the adjustment process, when T07 gradually approaches T08, the controller controls the neutralization unit to operate according to the pH value, so that the pH value of the condensed water in the air cooler is greater than or equal to 6.

5. When the controller determines that T+n>T08>T, and T07≥T08, the controller controls the three-way valve, the heater and the neutralization unit to be in a closed state; When the controller determines that T+n>T08>T, and T08>T07, the controller controls the three-way valve to gradually increase the opening from the closed state of 0% opening until T07=T08. If the three-way valve increases the opening to the open state of 100%, T07 is still less than T08, and the controller starts the heater to enter the working state until T07=T08. During the adjustment process, when T07 gradually approaches T08, the controller controls the neutralization unit to operate according to the pH value, so that the pH value of the condensed water in the air cooler is greater than or equal to 6.5, and reaches a stable state of T07=T08.

5. The system for controlling the generation of acidic condensed water in an exhaust gas recirculation system according to claim 1, characterized in that: The neutralization unit includes a nozzle arranged at the end of the pipeline, and the nozzle is arranged above the interior of the air cooler and is used for spraying neutralization liquid into the air cooler in real time.

6. The system for controlling the generation of acidic condensed water in an exhaust gas recirculation system according to claim 1, characterized in that: A liquid level meter is also included. The liquid level meter is arranged at a preset height from the inner bottom of the air cooler and is used to monitor the height of condensed water in the air cooler.

7. The system for controlling the generation of acidic condensed water in an exhaust gas recirculation system according to claim 1, characterized in that: A fresh water pump is also included. The fresh water pump is located between the three-way valve and the air cooler and is used to provide fresh water to enter the air cooler.

8. The system for controlling the generation of acidic condensed water in an exhaust gas recirculation system according to claim 2, characterized in that: The heater is arranged between the air cooler and the outlet of the cooling fresh water. When the three-way valve is in an open state with an opening degree of 100%, the cooling fresh water flowing out of the air cooler flows through the heater and is heated. The heated cooling fresh water then flows back to the air cooler through the three-way valve.

9. A method for controlling the generation of acidic condensed water in an exhaust gas recirculation system, characterized in that: The system for controlling the generation of acidic condensed water in an exhaust gas recirculation system according to any one of claims 1 to 8 comprises: Real-time monitoring of the temperature of the pressurized air at the gas outlet side of the air cooler; Real-time monitoring of the dew point value of the pressurized air at the gas outlet side of the air cooler; Real-time monitoring of the pH value of the charge air in the air cooler; By comparing the temperature of the pressurized air, the dew point of the pressurized air and the required temperature of the pressurized gas, the flow rate and temperature of the cooling fresh water entering the air cooler are controlled, and neutralizing liquid is delivered to the air cooler in real time to adjust the pH of the pressurized air.

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