An integrated thermal management system for an internal combustion engine and a control method thereof

Abstract

The application discloses an internal combustion engine integrated heat management system and a control method thereof, and relates to the field of internal combustion engine heat management systems. The internal combustion engine integrated heat management system comprises an internal combustion engine and a waste heat recovery system, wherein the waste heat recovery system comprises a working medium pump, a pressurized air preheater, a regenerator, a cylinder jacket water preheater, a flue gas heat exchanger, a turbine expander, a condenser and a liquid storage tank. The internal combustion engine integrated heat management system realizes waste heat recovery of the internal combustion engine by controlling the opening degree and opening and closing of a first flow regulating valve, a three-way valve, an on-off valve, a second flow regulating valve, a first expansion regulating mechanism and a second expansion regulating mechanism. The application sets valves and pumps on multiple branches, thereby controlling the waste heat utilization of flue gas, cylinder jacket water and pressurized air emitted by the internal combustion engine, and realizing the compatibility of waste heat recovery and heat management of the internal combustion engine.

Description

Technical Field

[0001] This invention belongs to the field of waste heat recovery technology for internal combustion engines, specifically relating to an integrated thermal management system for internal combustion engines coupled with a waste heat recovery system and its control method. Background Technology

[0002] Internal combustion engines are widely used in industrial production and account for a significant proportion of energy consumption. Therefore, energy conservation and emission reduction in internal combustion engines are crucial for achieving dual-carbon goals. However, approximately 50% or more of the heat from an internal combustion engine is wasted and carried into the environment by flue gas, cylinder liner water, and turbocharged air. Therefore, waste heat recovery technology is essential for improving the thermal efficiency of internal combustion engines. Furthermore, internal combustion engines have relatively strict requirements on the temperatures of cylinder liner water and turbocharged air, necessitating a dedicated internal combustion engine thermal management system. Integrating the internal combustion engine thermal management system with a waste heat recovery system into a single system can not only fully utilize waste heat to improve engine efficiency but also significantly reduce equipment redundancy, thereby enhancing the practical application value of the waste heat recovery system.

[0003] CN110905619A discloses a Rankine cycle system for recovering waste heat from an internal combustion engine. This system, based on the characteristics of the mixed working fluid and according to energy quality, utilizes different heat sources from the internal combustion engine in stages for waste heat recovery. However, the aforementioned system cannot simultaneously address the thermal management functions of the internal combustion engine, and cannot effectively control the temperature of the cylinder liner water and turbocharged air under all operating conditions, requiring the addition of an extra thermal management system. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and propose an integrated thermal management system for internal combustion engines coupled with a waste heat recovery system and its control method. This invention integrates the internal combustion engine thermal management system and the waste heat recovery system into one system. By setting valves and pump elements on multiple branches, it achieves compatibility between the utilization and thermal management of waste heat from the exhaust gas, cylinder liner water and turbocharged air emitted by the internal combustion engine.

[0005] The first aspect of the present invention is to provide an integrated thermal management system for an internal combustion engine, comprising an internal combustion engine and a waste heat recovery system, wherein the waste heat recovery system comprises a working fluid pump, a booster air preheater, a regenerator, a cylinder liner water preheater, a flue gas heat exchanger, a turbine expander, a condenser, and a liquid storage tank.

[0006] The inlet of the working fluid pump is connected to the liquid storage tank, and the outlet of the working fluid pump is divided into two branches. One branch is connected to the cold fluid side inlet of the booster air preheater through a pipeline, and the other branch is connected to the cold fluid side inlet of the regenerator through the first flow regulating valve.

[0007] The turbocharged air preheater includes a cold fluid side inlet, a cold fluid side outlet, a hot fluid side inlet, and a hot fluid side outlet. The turbocharged air discharged from the internal combustion engine first flows into the hot fluid side inlet of the turbocharged air preheater through a pipeline, and the hot fluid side outlet is connected to the internal combustion engine. The cold fluid side outlet is divided into four branches: one branch connects to the inlet of the second expansion regulating mechanism, and the outlet of the second expansion regulating mechanism merges with the working fluid at the outlet of the turbine expander; the second branch connects to the first port of the three-way valve, the second port of the three-way valve is connected to the cold fluid side inlet of the flue gas heat exchanger through a pipeline, and the third port of the three-way valve is connected to the cold fluid side outlet of the regenerator; the third branch connects to the inlet of the second flow regulating valve, and the outlet of the second flow regulating valve merges with the cold fluid side outlet of the cylinder liner water preheater; the fourth branch connects to the inlet of the switching valve, and the outlet of the switching valve connects to the cold fluid side inlet of the cylinder liner water preheater.

[0008] The cylinder liner water preheater includes a cold fluid side inlet, a cold fluid side outlet, a hot fluid side inlet, and a hot fluid side outlet. The cylinder liner water discharged from the internal combustion engine first flows into the hot fluid side inlet of the cylinder liner water preheater, and the hot fluid side outlet of the cylinder liner water preheater is connected to the internal combustion engine. The cold fluid side outlet of the cylinder liner water preheater is divided into two branches: one branch connects to the inlet of the first expansion regulating mechanism, and the outlet of the first expansion regulating mechanism merges with the working fluid at the outlet of the turbine expander; the other branch connects to the cold fluid side inlet of the flue gas heat exchanger.

[0009] The flue gas heat exchanger includes a cold fluid side inlet, a cold fluid side outlet, a hot fluid side inlet, and a hot fluid side outlet. The flue gas discharged from the internal combustion engine first flows into the hot fluid side inlet of the flue gas heat exchanger and then is discharged into the atmospheric environment from the hot fluid side outlet of the flue gas heat exchanger. The cold fluid side outlet of the flue gas heat exchanger is connected to the inlet of the turbine expander.

[0010] The outlet of the turbine expander merges with the outlets of the first expansion regulating mechanism and the second expansion regulating mechanism, and then connects to the hot fluid side inlet of the regenerator.

[0011] The hot fluid side outlet of the regenerator is connected to the hot fluid side inlet of the condenser, the hot fluid side outlet of the condenser is connected to the inlet of the liquid storage tank, and the outlet of the liquid storage tank is connected to the inlet of the working fluid pump.

[0012] The working principle of the integrated thermal management system for the internal combustion engine is as follows: The working fluid pump pressurizes the liquid cold working fluid in the storage tank, and then, after passing through the first flow regulating valve, it is delivered to the booster air preheater and the regenerator through pipelines respectively. In the booster air preheater, the working fluid cools the heat source booster air to the required temperature range. In the regenerator, the cold working fluid absorbs heat from the working fluid after the turboexpander. The first flow regulating valve is used to regulate the flow rate of the working fluid from the working fluid pump in the two branches. After the working fluid from the two branches (i.e., the cold fluid outlets from the booster air preheater and the regenerator) merges, it absorbs the heat from the cylinder liner water discharged from the internal combustion engine through the cylinder liner water preheater, cooling the cylinder liner water to the temperature range required for entering the internal combustion engine. The cold working fluid from the cylinder liner water preheater enters the flue gas heat exchanger to absorb the heat from the flue gas discharged from the internal combustion engine, and then becomes a high-temperature, high-pressure gas that expands and does work in the turboexpander. The expanded working fluid releases heat to the liquid cold working fluid flowing in through the working fluid pump in the regenerator, and then enters the condenser to be condensed back into liquid and stored in the storage tank. Finally, it is pressurized and transported by the working fluid pump to start the next cycle.

[0013] Furthermore, the integrated thermal management system for the internal combustion engine achieves compatibility between waste heat recovery and thermal management by controlling the opening and closing of a first flow regulating valve, a three-way valve, a switching valve, a second flow regulating valve, a first expansion regulating mechanism, and a second expansion regulating mechanism. Specifically: the first flow regulating valve regulates the working fluid flow rate in the turbocharged air preheater branch and the regenerator branch; the three-way valve controls the working fluid flow direction at the cold fluid side outlet of the regenerator; the switching valve opens / closes the working fluid flow path at the cold fluid side inlet of the cylinder liner water preheater; the second flow regulating valve regulates the working fluid flow rate in its branch; the first expansion regulating mechanism controls the working fluid flow rate in that branch, thereby controlling the temperature of the cylinder liner water after cooling; the second expansion regulating mechanism controls the working fluid flow rate in that branch, thereby controlling the temperature of the turbocharged air after cooling.

[0014] Furthermore, the first and second expansion regulating mechanisms are expansion regulating valves or expanders.

[0015] A second aspect of the present invention is to provide a control method utilizing the aforementioned integrated thermal management system for internal combustion engines, comprising:

[0016] When the internal combustion engine is in a hot state, that is, the temperature of the cylinder liner cooling water in the internal combustion engine is below 80-90℃, but the waste heat recovery system has been started, the flow direction of the three-way valve is controlled according to the condition of the working fluid on the cold side of the regenerator. The switching valve is closed, the first expansion regulating mechanism is closed, the second expansion regulating mechanism is closed, and the opening of the first flow regulating valve is adjusted to distribute the optimal working fluid flow of the booster air preheater branch and the regenerator branch so that the waste heat recovery system can obtain the maximum output power. The second flow regulating valve is fully opened. At this time, the working fluid at the cold fluid side outlet of the booster air preheater and the working fluid at the cold fluid side outlet of the regenerator merge and flow into the cold fluid side inlet of the flue gas heat exchanger after passing through the second flow regulating valve.

[0017] When the internal combustion engine and waste heat recovery system are working normally, the flow direction of the three-way valve is controlled according to the condition of the working fluid on the cold side of the regenerator; the opening of the first flow regulating valve is adjusted to distribute the optimal working fluid flow between the booster air preheater branch and the regenerator branch, and the switching valve is opened.

[0018] Determine the cylinder liner water temperature at the hot fluid side outlet of the cylinder liner water preheater:

[0019] If the cylinder liner water temperature is below 80-90℃, reduce the flow rate of the working fluid pump and monitor the following parameters in real time: the flow rate of the working fluid pump, the flow rate at the cold fluid side inlet of the cylinder liner water preheater, the temperature at the hot fluid side outlet of the cylinder liner water preheater, the temperature of the pressurized air at the hot fluid side outlet of the pressurized air preheater, and the working fluid temperature at the cold fluid side outlet of the flue gas heat exchanger. If any of the above parameters exceeds the preset limit, stop reducing the flow rate of the working fluid pump, open the second flow regulating valve and the second expansion regulating mechanism; control the final flow rate of the working fluid entering the cold fluid side inlet of the flue gas heat exchanger and the flow rate of the working fluid entering the cold fluid side inlet of the cylinder liner water preheater.

[0020] If the cylinder liner water temperature is higher than 95℃, increase the flow rate of the working fluid pump and monitor the working fluid temperature and pressure at the cold fluid outlet of the flue gas heat exchanger in real time. If the working fluid temperature loses superheat or the working fluid pressure rises to the point where the working fluid can no longer evaporate in the cylinder liner water preheater, while continuing to increase the flow rate of the working fluid pump, open the first expansion regulating mechanism to control the flow rate of the working fluid that finally enters the cold fluid side inlet of the flue gas heat exchanger; at this time, the second flow regulating valve and the second expansion regulating mechanism are completely closed.

[0021] Furthermore, when the internal combustion engine and waste heat recovery system are working normally, if the working fluid temperature at the cold fluid outlet of the booster air preheater exceeds 40-50℃, the working fluid flow rate at the working fluid pump outlet is increased, and the following parameters are monitored in real time: the cylinder liner water temperature at the hot fluid side outlet of the cylinder liner water preheater is not lower than 80℃ and the working fluid temperature at the cold fluid side outlet of the flue gas heat exchanger maintains a superheat greater than 0. If either of the above two parameters exceeds its limit, while continuing to increase the working fluid pump flow rate, the second expansion regulating mechanism is opened to control the working fluid flow rate entering the cold fluid side inlet of the cylinder liner water preheater and the cold fluid side inlet of the flue gas heat exchanger, so that the above two parameters return to the limit range.

[0022] Furthermore, controlling the flow direction of the three-way valve based on the condition of the working fluid on the cold side of the regenerator specifically includes:

[0023] Determine if the working fluid on the cold side of the regenerator is superheated. If so, close the first port of the three-way valve; otherwise, close the second port of the three-way valve.

[0024] Furthermore, when the internal combustion engine is in a hot state, if the working fluid temperature at the outlet of the pressurized air preheater exceeds 40-50°C, the working fluid flow rate at the outlet of the working fluid pump is increased, and the working fluid temperature at the outlet of the flue gas heat exchanger on the cold fluid side is monitored in real time (to maintain superheat greater than 0). If superheat is lost, the second expansion regulating mechanism is opened to control the flow rate entering the inlet of the flue gas heat exchanger on the cold fluid side, so that the superheat is restored to greater than 0.

[0025] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0026] The integrated thermal management system for internal combustion engines described in this invention controls the utilization of waste heat from exhaust gas, cylinder liner water, and turbocharged air emitted by the internal combustion engine by setting valves and pump elements on multiple branches, thereby achieving compatibility between waste heat recovery and thermal management of the internal combustion engine.

[0027] Moreover, this invention integrates the existing internal combustion engine thermal management system and waste heat recovery system into one system. Compared with the traditional internal combustion engine waste heat recovery system, it not only makes full use of waste heat to improve the efficiency of the internal combustion engine, but also significantly reduces the equipment redundancy of the internal combustion engine and improves the practical application value of the waste heat recovery system. Attached Figure Description

[0028] Figure 1 This is a structural schematic diagram of the integrated thermal management system for internal combustion engines described in this invention.

[0029] 1: Working fluid pump; 2: Pressurized air preheater; 3: Regenerator

[0030] 4: Cylinder liner water preheater; 5: Flue gas heat exchanger; 6: Turbine expander

[0031] 7: Condenser 8: Liquid receiver 9: Internal combustion engine

[0032] 10: First flow regulating valve; 11: Three-way valve; 12: On / off valve

[0033] 13: Second flow regulating valve; 14: First expansion regulating valve; 15: Second expansion regulating valve

[0034] 111: First interface; 112: Second interface; 113: Third interface Detailed Implementation

[0035] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The specific embodiments described are only for explanation and illustration of the present invention and are not intended to limit the present invention.

[0036] An integrated thermal management system for an internal combustion engine includes an internal combustion engine and a waste heat recovery system. The waste heat recovery system includes a working fluid pump 1, a booster air preheater 2, a regenerator 3, a cylinder liner water preheater 4, a flue gas heat exchanger 5, a turbine expander 6, a condenser 7, and a liquid storage tank 8.

[0037] The working principle of the integrated thermal management system for the internal combustion engine is as follows: The working fluid pump 1 pressurizes the liquid cold working fluid in the storage tank 8, and then, after passing through the first flow regulating valve 10, it is delivered to the booster air preheater 2 and the regenerator 3 via pipelines. In the booster air preheater 2, the working fluid cools the heat source booster air to the required temperature range. In the regenerator 3, the cold working fluid absorbs heat from the working fluid after the turboexpander 6. The first flow regulating valve 10 is used to regulate the flow rate of the working fluid from the working fluid pump 1 in the two branches. After the working fluid from the two branches (i.e., the cold fluid outlets from the booster air preheater 2 and the regenerator 3) merges, it absorbs heat from the cylinder liner water discharged from the internal combustion engine 9 through the cylinder liner water preheater 4, cooling the cylinder liner water to the temperature range required for entering the internal combustion engine. The cold working fluid exiting the cylinder liner water preheater 4 enters the flue gas heat exchanger 5 to absorb heat from the flue gas discharged from the internal combustion engine 9, and then becomes a high-temperature, high-pressure gas that expands and performs work in the turboexpander 6. The expanded working fluid releases heat to the liquid cold working fluid flowing in through the working fluid pump 1 in the regenerator 3, and then enters the condenser 7 to be condensed back into liquid and stored in the storage tank 8. Finally, it is pressurized and transported by the working fluid pump 1 to start the next cycle.

[0038] like Figure 1 As shown, the technical solution for the composition and component connection of the integrated thermal management system for internal combustion engines is as follows:

[0039] The exhaust gas from the internal combustion engine 9 serves as a heat source and is first connected to the hot fluid side inlet of the flue gas heat exchanger 5, and then flows out to the atmospheric environment from the hot fluid side outlet of the flue gas heat exchanger 5. The pressurized air formed by the exhaust gas from the internal combustion engine 9 after being pressurized by the turbocharger is first connected to the hot fluid side inlet of the pressurized air preheater 2, and the hot fluid side outlet of the pressurized air preheater 2 is connected to the intake manifold of the internal combustion engine. The cylinder liner water discharged from the internal combustion engine is first connected to the hot fluid side inlet of the cylinder liner water preheater 4, and the hot fluid side outlet of the cylinder liner water preheater 4 is connected to the internal combustion engine 9.

[0040] The outlet of the working fluid pump 1 is divided into two branches. One branch is connected to the cold fluid inlet of the booster air preheater 2 via a pipeline, and the other branch is first connected to the inlet of the first flow regulating valve 10. The outlet of the first flow regulating valve 10 is connected to the cold fluid side inlet of the regenerator 3. The cold fluid side outlet of the booster air preheater 2 is divided into four branches: one branch is connected to the inlet of the second expansion regulating valve 15, and the outlet of the second expansion regulating valve 15 merges with the working fluid at the outlet of the turbine expander 6; the second branch is connected to the first port of the three-way valve 11, and the second port of the three-way valve 11 is connected to the cold fluid side inlet of the flue gas heat exchanger 5 via a pipeline. The third port of the three-way valve 11 is connected to the cold fluid side outlet of the regenerator 3; the third branch is connected to the inlet of the second flow regulating valve 13, and the outlet of the second flow regulating valve 13 merges with the cold fluid side outlet of the cylinder liner water preheater 4; the fourth branch is connected to the inlet of the switch valve 12, and the outlet of the switch valve 12 is connected to the cold fluid side inlet of the cylinder liner water preheater 4. The cold fluid side outlet of the cylinder liner water preheater 4 is divided into two branches: one branch connects to the inlet of the first expansion regulating valve 14, and the outlet of the first expansion regulating valve 14 merges with the working fluid at the outlet of the turbine expander 6; the other branch connects to the cold fluid side inlet of the flue gas heat exchanger 5. The cold fluid outlet of the flue gas heat exchanger 5 is connected to the inlet of the turbine expander 6, and the outlet of the turbine expander 6 merges with the outlets of the first expansion regulating valve 14 and the second expansion regulating valve 15, then connects to the hot fluid side inlet of the regenerator 3. The hot fluid side outlet of the regenerator 3 is connected to the hot fluid side inlet of the condenser 7, and the hot fluid side outlet of the condenser 7 is connected to the inlet of the liquid storage tank 8. The outlet of the liquid storage tank 8 is connected to the inlet of the working fluid pump 1. The first expansion regulating valve 14 can also be replaced by an expander.

[0041] The three-way valve 11 is used to control the flow direction of the working fluid at the cold fluid side outlet of the regenerator 3. The first port of the three-way valve 11 is connected to the cold fluid side outlet of the booster air preheater 2 via a pipeline. The second port of the three-way valve 11 is connected to the cold fluid side inlet of the flue gas heat exchanger 5 via a pipeline. The third port of the three-way valve 11 is connected to the cold fluid side outlet of the regenerator 3. When the working fluid temperature at the outlet of the turbine expander 6 is high, causing superheating of the working fluid on the cold side inside the regenerator 3, the port connecting the three-way valve 11 and the switch valve 12 is closed. At this time, the cold fluid side outlet of the regenerator 3 is connected to the cold fluid side inlet of the flue gas heat exchanger 5 through the three-way valve 11. When the working fluid on the cold side inside the regenerator 3 has not reached the evaporation temperature or only a small amount of working fluid evaporates, the second port of the three-way valve is closed. At this time, the cold fluid side outlet of the regenerator 3 is connected to the inlet of the switch valve 12 through the three-way valve 11.

[0042] Switch valve 12 is used to close the working fluid flow path into the cold fluid side inlet of cylinder liner water preheater 4. Switch valve 12 is closed when the cylinder liner water temperature has not yet reached the temperature range required for normal operation of the internal combustion engine. Second flow regulating valve 13 is used to control the working fluid flow rate on this branch, and opens when switch valve 12 is closed to allow the working fluid to flow, bypassing the cylinder liner water preheater 4. First expansion regulating valve 14 is used to control the working fluid flow rate on this branch, thereby controlling the temperature of the cooled cylinder liner water. Second expansion regulating valve 15 is used to control the working fluid flow rate on this branch, thereby controlling the temperature of the cooled booster air.

[0043] The control method using the aforementioned integrated thermal management system for internal combustion engines specifically includes:

[0044] The flue gas heat exchanger 5, the booster air preheater 2, the cylinder liner water preheater 4, and the regenerator 3 all have a cold fluid side inlet, a cold fluid side outlet, a hot fluid side inlet, and a hot fluid side outlet. Flow sensors, temperature sensors, and pressure sensors are installed at each inlet / outlet to monitor the flow rate, temperature, and pressure of the fluid flowing through them. The monitored values ​​are uploaded to the controller of the thermal management system for controlling various valves and pumps based on the monitored values. Specific control strategies include:

[0045] When the internal combustion engine is in a hot state, i.e., the temperature of the cylinder liner cooling water is lower than the temperature required for normal operation of the internal combustion engine (approximately 80-90°C), but the waste heat recovery system has been activated, if the working fluid on the cold side of the regenerator 3 becomes superheated, the first port 111 of the three-way valve 11 is closed; otherwise, the second port 112 of the three-way valve 11 is closed. Then, the switching valve 12, the first expansion regulating valve 14, and the second expansion regulating valve 15 are closed. The first flow regulating valve 10 is opened to a suitable opening to adjust and distribute the optimal working fluid flow between the booster air preheater 2 branch and the regenerator 3 branch, so that the waste heat recovery system obtains maximum output power. The second flow regulating valve 13 is then fully opened. At this time, the working fluid at the cold fluid side outlet of the booster air preheater 2 and the working fluid at the cold fluid side outlet of the regenerator 3 merge and flow into the cold fluid side inlet of the flue gas heat exchanger 5 after passing through the second flow regulating valve 13. At the same time, in order to cool the booster air to the temperature required to enter the internal combustion engine, the working fluid flow rate at the outlet of the working fluid pump 1 can be increased. However, if the working fluid flow rate is too large, causing the working fluid temperature at the cold fluid side outlet of the flue gas heat exchanger 5 to lose superheat, i.e., it cannot evaporate completely, the second expansion regulating valve 15 should be opened appropriately to control the flow rate entering the cold fluid side inlet of the flue gas heat exchanger 5.

[0046] In the hot-engine state, the working process of the waste heat recovery system includes: the working fluid pump 1 pressurizes the liquid cold working fluid in the storage tank 8, and then, after passing through the first flow regulating valve 10, it is delivered to the booster air preheater 2 and the regenerator 3 through pipelines respectively; in the booster air preheater 2, the working fluid cools the boosted air from the internal combustion engine to the required temperature range; in the regenerator 3, the cold working fluid absorbs heat from the working fluid after the turboexpander 6; the working fluid from the cold fluid side outlets of the booster air preheater 2 and the regenerator 3 merge and, according to the recovery... The flow direction of the working fluid on the cold side inside the heat exchanger 3 is controlled by the three-way valve 11. After passing through the second flow regulating valve 13, the cold working fluid flows into the cold fluid side inlet of the flue gas heat exchanger 5 to absorb heat from the internal combustion engine flue gas. Then it becomes a high-temperature and high-pressure gas and expands in the turbine expander 6 to do work. The expanded working fluid releases heat to the liquid cold working fluid flowing in through the working fluid pump 1 in the regenerator 3. Then it enters the condenser 7 and is re-condensed into a liquid state and stored in the liquid storage tank 8. Finally, it is pressurized and transported by the working fluid pump 1 to start the next cycle.

[0047] When the internal combustion engine and waste heat recovery system are working normally, if the working fluid on the cold side of the regenerator 3 becomes superheated (i.e., a certain amount of evaporation occurs), the first port 111 of the three-way valve 11 is closed; otherwise, the second port 112 of the three-way valve 11 is closed. The first flow regulating valve 10 is adjusted to a suitable opening to distribute the optimal working fluid flow between the branch of the boosted air preheater 2 and the branch of the regenerator 3, and the switching valve 12 is opened. In the boosted air preheater 2, the working fluid cools the boosted air from the internal combustion engine to the required temperature range. In the regenerator 3, the cold working fluid absorbs heat from the working fluid after the turboexpander 6. The working fluids from the cold fluid side outlets of the boosted air preheater 2 and the regenerator 3 are combined.

[0048] The operation of other valves is as follows:

[0049] 1) If the cylinder liner water temperature at the hot fluid side outlet of the cylinder liner water preheater 4 is lower than 80°C, reduce the flow rate of the working fluid pump 1 to reduce the flow rate at the cold fluid side inlet of the cylinder liner water preheater 4, thereby increasing the cylinder liner water temperature at the hot fluid side outlet of the cylinder liner water preheater 4. As the flow rate of the working fluid pump 1 decreases, the temperature of the pressurized air at the hot fluid side outlet of the pressurized air preheater 2 will increase, the working fluid temperature at the cold fluid side outlet of the flue gas heat exchanger 5 will increase, the system pressure will decrease, and the flue gas waste heat utilization rate and regenerative utilization rate will decrease. If any of the above five parameters changes to exceed the preset limit value, stop reducing the flow rate of the working fluid pump 1. At the same time, by opening the second flow regulating valve 13 and the second expansion regulating valve 15 and adjusting their opening, control the working fluid flow rate that finally enters the cold fluid side inlet of the flue gas heat exchanger 5 and the working fluid flow rate that enters the cold fluid side inlet of the cylinder liner water preheater 4, thereby controlling the above parameters within the limit value range.

[0050] 2) If the cylinder liner water temperature at the hot fluid side outlet of the cylinder liner water preheater 4 is higher than approximately 95°C, increase the flow rate of the working fluid pump 1 to increase the flow rate at the cold fluid side inlet of the cylinder liner water preheater 4, thereby reducing the cylinder liner water temperature at the hot fluid side outlet of the cylinder liner water preheater 4. As the flow rate of the working fluid pump 1 increases, the working fluid temperature at the cold fluid side outlet of the flue gas heat exchanger 5 will decrease or even fail to evaporate completely, and the working fluid pressure at the cold fluid outlet of the flue gas heat exchanger 5 will increase. These factors will severely affect the system performance, and the working fluid temperature and pressure at the cold fluid outlet of the flue gas heat exchanger 5 must be limited to a certain range. Therefore, when the flow rate of the working fluid pump 1 increases to the point that the working fluid temperature loses its superheat, or the working fluid pressure rises to the point that the working fluid can no longer evaporate in the cylinder liner water preheater 4, while continuing to increase the flow rate of the working fluid pump 1, open the first expansion regulating valve 14 to control the flow rate of the working fluid that finally enters the cold fluid side inlet of the flue gas heat exchanger 5, thereby increasing the working fluid temperature at the cold fluid side outlet of the flue gas heat exchanger 5 and reducing the working fluid pressure there. At this time, the second flow regulating valve 13 and the second expansion regulating valve 15 are completely closed.

[0051] 3) When the internal combustion engine and waste heat recovery system are working, if the working fluid temperature at the cold fluid outlet of the booster air preheater 2 exceeds 40°C, the working fluid flow rate at the outlet of the working fluid pump 1 should be increased. However, if the working fluid flow rate is too high, the cylinder liner water temperature at the hot fluid side outlet of the cylinder liner water preheater 4 and the working fluid temperature at the cold fluid side outlet of the flue gas heat exchanger 5 will be too low, or even unable to evaporate completely. These two parameters should be monitored in real time. If the cylinder liner water temperature is below 80°C or the working fluid temperature remains above 0°C, the second expansion regulating valve 15 must be opened and its opening adjusted while continuing to increase the working fluid flow rate of the working fluid pump 1. This controls the working fluid flow rate entering the cold fluid side inlet of the cylinder liner water preheater 4 and the cold fluid side inlet of the flue gas heat exchanger 5, restoring these two parameters to their limit ranges.

[0052] Although preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these are within the scope of protection of the present invention.

Claims

1. An integrated thermal management system for an internal combustion engine, comprising an internal combustion engine (9) and a waste heat recovery system, wherein the waste heat recovery system comprises a working fluid pump (1), a booster air preheater (2), a regenerator (3), a cylinder liner water preheater (4), a flue gas heat exchanger (5), a turbine expander (6), a condenser (7), and a liquid storage tank (8); in, The inlet of the working fluid pump (1) is connected to the liquid storage tank (8), and the outlet of the working fluid pump (1) is divided into two branches. One branch is connected to the cold fluid side inlet of the pressurized air preheater (2) through a pipeline, and the other branch is connected to the cold fluid side inlet of the regenerator (3) through the first flow regulating valve (10). The booster air preheater (2) includes a cold fluid side inlet, a cold fluid side outlet, a hot fluid side inlet, and a hot fluid side outlet. The boosted air discharged from the internal combustion engine first flows into the hot fluid side inlet of the booster air preheater (2) through a pipe. The hot fluid side outlet is connected to the internal combustion engine. The cold fluid side outlet is divided into four branches: one branch connects to the inlet of the second expansion regulating mechanism (15), and the outlet of the second expansion regulating mechanism (15) merges with the working fluid at the outlet of the turbine expander (6); the second branch connects to the three-way valve (11). The first port of the three-way valve (11) is connected to the cold fluid side inlet of the flue gas heat exchanger (5) through a pipeline, and the third port of the three-way valve (11) is connected to the cold fluid side outlet of the regenerator (3); the third branch is connected to the inlet of the second flow regulating valve (13), and the outlet of the second flow regulating valve (13) is connected to the cold fluid side outlet of the cylinder liner water preheater (4); the fourth branch is connected to the inlet of the switch valve (12), and the outlet of the switch valve (12) is connected to the cold fluid side inlet of the cylinder liner water preheater (4); The cylinder liner water preheater (4) includes a cold fluid side inlet, a cold fluid side outlet, a hot fluid side inlet, and a hot fluid side outlet. The cylinder liner water discharged from the internal combustion engine first flows into the hot fluid side inlet of the cylinder liner water preheater (4), and the hot fluid side outlet of the cylinder liner water preheater (4) is connected to the internal combustion engine (9). The cold fluid side outlet of the cylinder liner water preheater (4) is divided into two branches: one branch is connected to the inlet of the first expansion regulating mechanism (14), and the outlet of the first expansion regulating mechanism (14) is connected to the turbine expansion... The working fluid at the outlet of the engine (6) is combined; another branch is connected to the cold fluid side inlet of the flue gas heat exchanger (5); the flue gas heat exchanger (5) includes a cold fluid side inlet, a cold fluid side outlet, a hot fluid side inlet and a hot fluid side outlet. The flue gas discharged from the internal combustion engine (9) first flows into the hot fluid side inlet of the flue gas heat exchanger (5), and then is discharged to the atmospheric environment from the hot fluid side outlet of the flue gas heat exchanger (5); the cold fluid side outlet of the flue gas heat exchanger (5) is connected to the inlet of the turboexpander (6); The outlet of the turbine expander (6) is connected to the outlets of the first expansion regulating mechanism (14) and the second expansion regulating mechanism (15), and then connected to the hot fluid side inlet of the regenerator (3). The hot fluid side outlet of the regenerator (3) is connected to the hot fluid side inlet of the condenser (7), the hot fluid side outlet of the condenser (7) is connected to the inlet of the liquid storage tank (8), and the outlet of the liquid storage tank (8) is connected to the inlet of the working fluid pump (1).

2. The integrated thermal management system for internal combustion engines according to claim 1, characterized in that, The integrated thermal management system for internal combustion engines achieves compatibility between waste heat recovery and thermal management of the internal combustion engine by controlling the opening and closing of the first flow regulating valve (10), three-way valve (11), on / off valve (12), second flow regulating valve (13), first expansion regulating mechanism (14), and second expansion regulating mechanism (15). The first flow regulating valve (10) is used to regulate the working fluid flow of the booster air preheater (2) branch and the regenerator (3) branch; The three-way valve (11) is used to control the flow direction of the working fluid at the cold fluid side outlet of the regenerator (3); The switching valve (12) is used to open / close the working fluid flow path at the cold fluid side inlet of the cylinder liner water preheater (4); The second flow regulating valve (13) is used to regulate the flow rate of the working fluid on the branch. The first expansion regulating mechanism (14) is used to control the flow rate of the working fluid on the branch, thereby controlling the temperature after the cylinder liner is cooled by water; The second expansion regulating mechanism (15) is used to control the flow rate of the working fluid on the branch, thereby controlling the temperature of the pressurized air after cooling.

3. The control method for the integrated thermal management system of an internal combustion engine according to claim 1, comprising: When the internal combustion engine is in a hot state, that is, the temperature of the internal combustion engine cylinder liner cooling water is lower than 80-90℃, but the waste heat recovery system has been started, the flow direction of the three-way valve (11) is controlled according to the working fluid condition on the cold side of the regenerator (3), the switching valve (12) is closed, the first expansion regulating mechanism (14) is closed, the second expansion regulating mechanism (15) is closed, the opening of the first flow regulating valve (10) is adjusted to distribute the optimal working fluid flow of the booster air preheater (2) branch and the regenerator (3) branch so that the waste heat recovery system can obtain the maximum output power, and the second flow regulating valve (13) is fully opened; at this time, the working fluid at the cold fluid side outlet of the booster air preheater (2) and the working fluid at the cold fluid side outlet of the regenerator (3) merge and then flow into the cold fluid side inlet of the flue gas heat exchanger (5) through the second flow regulating valve (13); When the internal combustion engine and waste heat recovery system are working normally, the flow direction of the three-way valve (11) is controlled according to the working fluid condition on the cold side of the regenerator (3); the opening of the first flow regulating valve (10) is adjusted to distribute the optimal working fluid flow of the booster air preheater (2) branch and the regenerator (3) branch, and the switch valve (12) is opened. Determine the cylinder liner water temperature at the hot fluid side outlet of the cylinder liner water preheater (4): If the cylinder liner water temperature is below 80-90℃, reduce the flow rate of the working fluid pump (1) and monitor the following parameters in real time: the flow rate of the working fluid pump (1), the flow rate of the cold fluid side inlet of the cylinder liner water preheater (4), the temperature at the hot fluid side outlet of the cylinder liner water preheater (4), the temperature of the pressurized air at the hot fluid side outlet of the pressurized air preheater (2), and the working fluid temperature at the cold fluid side outlet of the flue gas heat exchanger (5). If any of the above parameter values ​​exceeds the preset limit value, stop reducing the flow rate of the working fluid pump (1), open the second flow regulating valve (13) and the second expansion regulating mechanism (15); control the working fluid flow rate that finally enters the cold fluid side inlet of the flue gas heat exchanger (5) and the working fluid flow rate that enters the cold fluid side inlet of the cylinder liner water preheater (4). If the cylinder liner water temperature is higher than 95°C, increase the flow rate of the working fluid pump (1) and monitor the working fluid temperature and pressure at the cold fluid outlet of the flue gas heat exchanger (5) in real time. If the working fluid temperature loses superheat or the working fluid pressure rises to the point that the working fluid can no longer evaporate in the cylinder liner water preheater (4), while continuing to increase the flow rate of the working fluid pump (1), open the first expansion regulating mechanism (14) to control the flow rate of the working fluid that finally enters the cold fluid side inlet of the flue gas heat exchanger (5). At this time, the second flow regulating valve (13) and the second expansion regulating mechanism (15) are completely closed.

4. The control method according to claim 3, characterized in that, When the internal combustion engine and waste heat recovery system are working normally, if the working fluid temperature at the cold fluid outlet of the booster air preheater (2) exceeds 40-50℃, increase the working fluid flow rate at the outlet of the working fluid pump (1) and monitor the following parameters in real time: the cylinder liner water temperature at the hot fluid side outlet of the cylinder liner water preheater (4) is not lower than 80℃ and the working fluid temperature at the cold fluid side outlet of the flue gas heat exchanger (5) is kept at a superheat greater than 0. If either of the above two parameters exceeds its limit, while continuing to increase the flow rate of the working fluid pump (1), open the second expansion regulating mechanism (15) to control the working fluid flow rate entering the cold fluid side inlet of the cylinder liner water preheater (4) and the cold fluid side inlet of the flue gas heat exchanger (5) so that the above two parameters return to the limit range.

5. The control method according to claim 3, characterized in that, The flow direction of the three-way valve (11) is controlled according to the condition of the working fluid on the cold side of the regenerator (3), specifically including: Determine whether the working fluid on the internal cooling side of the regenerator (3) is superheated. If so, close the first port (111) of the three-way valve (11); otherwise, close the second port (112) of the three-way valve (11).

6. The control method according to claim 3, characterized in that, When the internal combustion engine is in a hot state, if the working fluid temperature at the cold fluid outlet of the booster air preheater (2) exceeds 40-50℃, increase the working fluid flow rate at the outlet of the working fluid pump (1), and monitor the working fluid temperature at the cold fluid side outlet of the flue gas heat exchanger (5) in real time to maintain a superheat greater than 0. When superheat is lost, the second expansion regulating mechanism (15) is opened to control the flow rate into the cold fluid side inlet of the flue gas heat exchanger (5). To restore the superheat to a value greater than 0.

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