System and method for controlling coolant of vehicle

Abstract

The invention relates to a system and a method for controlling coolant of a vehicle. The system may include an integrated flow control valve configured to open and close a branch line for supplying coolant discharged from an engine of a vehicle to an automatic transmission oil (ATF) warmer, a heater, and a radiator, respectively; a waste heat recovery system configured to exchange heat between exhaust gas discharged from the engine and a coolant discharged from the engine; and a controller configured to control the integrated flow control valve to open or close the branch line according to a temperature of outside air, a temperature of a coolant discharged by the engine, and a temperature of a coolant discharged by the waste heat recovery system to supply the coolant to the ATF warmer, the heater, and the radiator, respectively, and controlling the waste heat recovery system to allow heat exchange between the exhaust gas and the coolant.

Description

Technical Field

[0001] This disclosure relates to a system and method for controlling the coolant in a vehicle. Background Technology

[0002] Because the exhaust gases emitted from the engine after combustion contain heat energy, a waste heat recovery system (EHRS) is installed on the exhaust pipe to utilize this energy to accelerate engine preheating or for cabin heating. The waste heat recovery system is configured to allow heat exchange between the coolant and the exhaust gases, allowing the coolant to absorb heat from the exhaust gases and heat itself.

[0003] For hybrid vehicles that use both an engine and an electric motor as power sources, the electric motor drives the vehicle during the initial start-up phase, but as the vehicle speed increases, the engine is activated to drive the vehicle. When the engine starts running during vehicle operation, coolant heated by the waste heat recovery system is supplied to the engine to quickly preheat it, thus enabling the engine to reach a preheated state quickly. On the other hand, coolant is supplied from the waste heat recovery system to the heater, where it is used to heat the vehicle.

[0004] Because the high-temperature exhaust gas flows through the waste heat recovery system, the coolant needs to constantly flow within the waste heat recovery system.

[0005] However, when the vehicle's integrated flow control valve (ITM; integrated thermal management) performs its flow-stop function, it stops the coolant flow until the engine is preheated, preventing coolant from circulating in the waste heat recovery system. Consequently, the waste heat recovery system cannot cool, leading to boiling. This increased internal pressure within the system can damage vulnerable components.

[0006] To avoid this situation, when the flow stops, the bypass valve of the waste heat recovery system should be opened to allow the waste gas to bypass the flow, so that the waste gas can be discharged directly without exchanging heat with the coolant.

[0007] However, this waste heat recovery system employs a structure that utilizes wax that expands according to the temperature of the coolant entering the system to open the bypass valve. Consequently, the controller cannot operate the waste heat recovery system at the expected time. Even if boiling occurs inside the waste heat recovery system, the bypass valve will not open if there is no flow at the inlet or if the coolant filling the inlet is at a low temperature. Therefore, the exhaust gas continuously transfers heat to the coolant within the waste heat recovery system, leading to damage to its vulnerable components. Summary of the Invention

[0008] This disclosure relates to a system and method for controlling the coolant in a vehicle, which can control the flow of coolant in an integrated manner based on the outside air temperature and the coolant temperature via an integrated flow control valve and a waste heat recovery system, wherein the integrated flow control valve controls the flow of coolant in the vehicle and the waste heat recovery system can recover heat from exhaust gas to heat the engine coolant.

[0009] Therefore, taking into account the above points, embodiments of this disclosure can provide a system and method for controlling the coolant of a vehicle, which can prevent boiling damage in the waste heat recovery system while rapidly preheating the powertrain including the engine, and allow the coolant to selectively flow through the automatic transmission fluid (ATF) warmer and heater based on the temperature of the outside air and the temperature of the coolant, and then through the waste heat recovery system, thereby improving the fuel efficiency of the vehicle.

[0010] To achieve the above advantages, according to embodiments of this disclosure, a system for controlling the coolant of a vehicle may include: an integrated flow control valve configured to open and close branch lines for supplying coolant discharged from the vehicle's engine to an ATF heater, a heater, and a radiator, respectively; a waste heat recovery system configured to perform heat exchange between exhaust gas discharged from the engine and coolant discharged from the engine; a main water pump configured to circulate the coolant; and a controller configured to control the integrated flow control valve to open and close the branch lines based on the outside air temperature, the coolant temperature discharged from the engine, and the coolant temperature discharged from the waste heat recovery system, to supply coolant from the integrated flow control valve to the ATF heater, the heater, and the radiator, respectively, and to control the waste heat recovery system to allow heat exchange between exhaust gas and coolant, wherein a return line may be provided to circulate coolant from the waste heat recovery system to the ATF heater and the heater, respectively, and the controller may control the circulation of coolant from the waste heat recovery system to the ATF heater or the heater based on the outside air temperature.

[0011] According to embodiments of this disclosure, a method for controlling the coolant in a vehicle may include: a first external air temperature comparison step, wherein a controller compares the temperature of external air with a preset reference temperature to identify which of the engine exhaust coolant should be circulated to, the ATF heater or the heater, and determines the time for stopping heat exchange between the coolant and the waste heat recovery system; a circulation step, wherein based on the external air temperature, the controller controls the supply of coolant discharged from the waste heat recovery system to the ATF heater or the heater; an exhaust heat recovery step, wherein the controller controls the supply of engine exhaust coolant to the waste heat recovery system; a coolant temperature comparison step, wherein the controller identifies whether the temperature of the coolant discharged from the waste heat recovery system exceeds a bypass temperature, the bypass temperature being set to allow the coolant to bypass the waste heat recovery system; and a bypass step, wherein when the coolant temperature exceeds the bypass temperature, the controller controls the allowance of exhaust gas to bypass the coolant, thereby allowing exhaust gas to flow through the waste heat recovery system, wherein in the bypass step, the controller may operate the drive motor of the waste heat recovery system to allow exhaust gas to flow and bypass the coolant through the waste heat recovery system.

[0012] According to embodiments of this disclosure, a method for controlling the coolant in a vehicle may include: a second external air temperature comparison step, wherein a controller compares the external air temperature with a preset reference temperature to determine the operating mode of the waste heat recovery system and the integrated flow control valve; a mode activation step, wherein based on the external air temperature, the controller causes the integrated flow control valve to enter a set, selected, or predetermined operating mode; a bypass identification step, wherein the controller identifies whether exhaust gas flows through the waste heat recovery system without exchanging heat with the coolant; a flow stop identification step, wherein the controller identifies whether the integrated flow control valve is controlled in a flow stop state; a flow stop release step, wherein the controller releases the flow stop control of the integrated flow control valve; a coolant temperature condition comparison step, wherein the controller identifies whether the temperature of the coolant discharged from the waste heat recovery system is lower than the recovery start temperature when the temperature of the coolant discharged from the waste heat recovery system exceeds the temperature of the coolant discharged from the engine, the recovery start temperature being preset to trigger the exhaust gas heat recovery control entering the waste heat recovery system; and an exhaust gas heat recovery activation step, wherein the controller controls the waste heat recovery system to recover exhaust gas heat.

[0013] According to embodiments of this disclosure, in systems and methods for controlling the coolant of a vehicle (e.g., systems and methods having one of the above configurations), preheating of the powertrain system, including the engine and transmission, can be performed quickly.

[0014] In this way, the preheating of the powertrain can be accelerated, thus improving the vehicle's fuel efficiency. The reduced preheating time also improves exhaust performance, thereby reducing the emission of harmful substances.

[0015] By utilizing embodiments of this disclosure, hybrid vehicles can reduce the associated costs of installing PTC heaters because they do not require the installation of PTC heaters for preheating the vehicle interior. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating a coolant control system for a vehicle according to an embodiment of the present disclosure.

[0017] Figure 2A This is a schematic diagram illustrating the coolant circulation through an ATF heater and a waste heat recovery system in a vehicle coolant control system according to an embodiment of the present disclosure.

[0018] Figure 2B This is a schematic diagram illustrating a vehicle coolant control system according to an embodiment of the present disclosure, in which the coolant circulates through the engine and the waste heat recovery system, and the coolant also circulates through the ATF heater and the waste heat recovery system.

[0019] Figure 3A This is a schematic diagram illustrating the circulation of coolant through a heater and a waste heat recovery system in a vehicle coolant control system according to an embodiment of the present disclosure.

[0020] Figure 3B This is a schematic diagram illustrating a vehicle coolant control system according to an embodiment of the present disclosure, in which coolant circulates through the heater and the waste heat recovery system while the coolant circulates through the engine and the waste heat recovery system.

[0021] Figure 4 This is a perspective view showing an electronic waste heat recovery system for a vehicle's coolant control system, according to an embodiment of the present disclosure, installed in an exhaust gas pipeline.

[0022] Figure 5 This is a flowchart illustrating a method for controlling the coolant of a vehicle according to an embodiment of the present disclosure.

[0023] Figure 6A and Figure 6B This is a flowchart illustrating a method for controlling the coolant of a vehicle according to an embodiment of the present disclosure. Detailed Implementation

[0024] In the following, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Since these exemplary embodiments, which are examples, can be implemented in various different forms by those skilled in the art to which this disclosure pertains, the present disclosure is not necessarily limited to the exemplary embodiments described herein.

[0025] Hereinafter, a system and method for controlling the coolant of a vehicle according to embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0026] Figure 1 This is a schematic diagram illustrating a coolant control system for a vehicle according to an embodiment of the present disclosure. Figure 2A This is a schematic diagram illustrating the coolant circulation through an ATF heater and a waste heat recovery system in a vehicle coolant control system according to an embodiment of the present disclosure. Figure 2B This is a schematic diagram illustrating a vehicle coolant control system according to an embodiment of the present disclosure, in which the coolant circulates through the engine and the waste heat recovery system, and the coolant also circulates through the ATF heater and the waste heat recovery system. Figure 3A This is a schematic diagram illustrating the coolant circulation through a heater and a waste heat recovery system in a vehicle coolant control system according to an embodiment of the present disclosure. Figure 3B This is a schematic diagram illustrating a vehicle coolant control system according to an embodiment of the present disclosure, in which the coolant circulates through the heater and the waste heat recovery system while the coolant circulates through the engine and the waste heat recovery system. Figure 4 This is a perspective view showing an electronic waste heat recovery system for a vehicle's coolant control system, according to an embodiment of the present disclosure, installed in an exhaust gas pipeline. Figure 5 This is a flowchart illustrating a method for controlling the coolant of a vehicle according to an embodiment of the present disclosure.

[0027] A system for controlling the coolant of a vehicle according to embodiments of the present disclosure may include: an integrated flow control valve 30 capable of opening and closing branch lines 43, 44, and 45 for supplying coolant discharged from the engine 10 to the ATF heater 23, heater 24, and radiator 26, respectively; a waste heat recovery system 25 for heat exchange between exhaust gas discharged from the engine 10 and coolant discharged from the engine 10; a main water pump 21 for circulating the coolant; and a controller 50 capable of controlling the integrated flow control valve 30 to open or close branch lines 43, 44, and 45 based on the outside air temperature, the coolant temperature discharged from the engine 10, and the coolant temperature discharged from the waste heat recovery system 25, to supply coolant to the ATF heater 23, heater 24, and radiator 26, and also capable of controlling the waste heat recovery system 25 to allow heat exchange between exhaust gas and coolant. Return lines 47 and 48 can be provided to circulate coolant from the waste heat recovery system 25 to the ATF heater 23 and heater 24, respectively. The controller 50 can control the circulation of coolant from the waste heat recovery system 25 to the ATF heater 23 or heater 24 based on the temperature of the outside air.

[0028] The engine 10 can discharge the exhaust gases produced by combustion to the outside through the exhaust pipe 15. The engine 10 is heated during operation and cooled by a coolant.

[0029] Engine 10 can be equipped with various sensors to detect the engine's status and send the outputs of these sensors to the engine management system (EMS) that controls engine 10 to control its operation. The sensors can also output sensed values ​​to controller 50, where these values ​​can be used as input values ​​for executing controls. For example, the flow of coolant can be controlled differently based on the temperature of the coolant discharged from engine 10.

[0030] The vehicle equipped with engine 10 can be a hybrid vehicle. Hybrid vehicles can have phases such as just starting, idling, or downhill driving, during which engine 10 does not run even after the vehicle has started. In this way, during the phases when engine 10 is not running, heat from the exhaust gases can be transferred to engine 10 via the waste heat recovery system 25, described below, allowing engine 10 to maintain an appropriate temperature. Therefore, embodiments of this disclosure are particularly suitable for hybrid vehicles.

[0031] The main water pump 21 circulates the coolant to ensure that the engine 10 maintains an appropriate temperature. The main water pump 21 circulates the coolant through the main cooling line 41, thereby cooling the engine 10.

[0032] The EGR cooling line 42, branching from the main cooling line 41, allows coolant to circulate through the main water pump 21 and the EGR cooler 22, thereby reducing the temperature of the air recirculated to the engine 10 via exhaust gas recirculation (EGR).

[0033] The integrated flow control valve 30 (ITM; integrated thermal management) can operate based on the coolant discharged from the engine 10 and can determine the direction of coolant flow, which is controlled by the controller 50 described below. The integrated flow control valve 30 can determine whether the coolant is flowing in three directions and the flow rate.

[0034] Transmission fluid can flow inside the ATF heater 23, and heat exchange can occur between the coolant and the transmission fluid. The ATF heater 23 can be connected to the integrated flow control valve 30 and the first branch line 43, and the first branch line 43 can be connected to the main cooling line 41.

[0035] Heater 24 can heat the air entering the vehicle. Heater 24 heats the air entering the vehicle by exchanging heat between the air and the coolant. Heater 24 can be connected to integrated flow control valve 30 and second branch line 44.

[0036] Radiator 26 cools the coolant by exchanging heat between the coolant and outside air. Radiator 26 can be connected to an integrated flow control valve 30 and a third branch line 45, and the third branch line 45 can be integrated into the main cooling line 41. As the coolant flows through radiator 26, it can exchange heat with outside air supplied by a drive fan or cooling fan, thereby cooling the coolant.

[0037] The integrated flow control valve 30 can receive control signals from the controller 50, which will be described below, and can open and close branch lines 43, 44, and 45, which can supply coolant discharged from the engine 10 to the ATF heater 23, heater 24, and radiator 26, respectively. The integrated flow control valve 30 can open and close the first branch line 43 connected to the ATF heater 23, the second branch line 44 connected to the heater 24, and the third branch line 45 connected to the radiator 26, respectively. The integrated flow control valve 30 can circulate the coolant supplied to the engine 10 to one or more of the ATF heater 23, heater 24, or radiator 26. The integrated flow control valve 30 can control the coolant flow to stop, thereby preventing coolant from flowing to any one of the ATF heater 23, heater 24, or radiator 26. For example, before the engine 10 is preheated, the coolant flow can be controlled to stop to prevent the coolant from cooling the engine 10, thereby promoting the preheating of the engine 10.

[0038] The waste heat recovery system (EHRS) 25 can be installed in the exhaust gas line 15 and can allow coolant to flow inside the waste heat recovery system 25 to exchange heat with the exhaust gas discharged through the exhaust gas line 15.

[0039] Waste heat recovery system 25 can be installed on waste gas heat recovery pipeline 46, which branches off from heater 24 and connects to main cooling pipeline 41. Waste heat recovery system 25 can receive coolant discharged from heater 24, and the coolant discharged from waste heat recovery system 25 can be connected to main cooling pipeline 41. Waste gas heat recovery pipeline 46 can be equipped with auxiliary water pump 27 to circulate coolant in waste heat recovery system 25.

[0040] The coolant entering the waste heat recovery system 25 through inlet 25a can exchange heat with the exhaust gas and can then be discharged through outlet 25b. The waste heat recovery system 25 may be equipped with a valve for controlling the flow path of the exhaust gas. In the prior art, this valve has a wax-based actuator filled with wax that expands according to the coolant temperature. However, in embodiments of this disclosure, a drive motor 25c can be provided as the actuator, and the drive motor 25c can operate based on control signals from the controller 50. Various examples of constructions that operate a waste heat recovery system by the expansion of wax have been disclosed in the applicant's patent applications, including Korean Patent Publication No. 10-2022-0059071 and Korean Patent Publication No. 10-2022-0006896. Embodiments of this disclosure may replace the wax-based actuator in such waste heat recovery systems with a drive motor 25c. Because the waste heat recovery system 25 can be controlled to operate for the required time via control signals, boiling in the waste heat recovery system can be prevented using embodiments of this disclosure.

[0041] A water temperature sensor 25d can be installed at the outlet 25b to measure the temperature of the coolant discharged from the waste heat recovery system 25 and output the measured temperature to the controller 50.

[0042] Because the waste heat recovery system 25 can operate electronically based on the control signals of the controller 50, it can be controlled under various conditions. The controller 50 can operate under the control of the vehicle's engine management system (EMS), thus allowing easy control of the waste heat recovery system 25 according to the vehicle's status.

[0043] The waste heat recovery system 25 and the integrated flow control valve 30 can be controlled together to achieve combined operation.

[0044] Embodiments of this disclosure can ensure the formation of a closed loop in which coolant can be circulated from waste heat recovery system 25 to ATF heater 23 and heater 24, respectively.

[0045] That is, a first return line 47 can be provided to allow the coolant to flow back from the waste heat recovery system 25 to the ATF heater 23, and a first switch valve 23a that can open and close the first return line 47 can be provided on the first return line 47.

[0046] A second return line 48 can be provided to allow coolant to flow back from the waste heat recovery system 25 to the heater 24, and a second switch valve 24a can be provided on the second return line 48 to open and close the second return line 48. An auxiliary water pump 27 can operate between the heater 24 and the waste heat recovery system 25 to supply coolant to the waste heat recovery system 25.

[0047] The controller 50 can control the operation of the waste heat recovery system 25, the integrated flow control valve 30, the first switching valve 23a, the second switching valve 24a, the main water pump 21, and the auxiliary water pump 27 according to set, selected, or predetermined logic. That is, the controller 50 can control the integrated flow control valve 30 to open and close the first branch line 43, the second branch line 44, and the third branch line 45 based on the outside air temperature, the coolant temperature discharged from the engine 10, and the coolant temperature discharged from the waste heat recovery system 25. These branch lines can supply coolant from the integrated flow control valve 30 to the ATF heater 23, the heater 24, and the radiator 26, respectively. The controller 50 can also control the waste heat recovery system 25 to enable heat exchange between exhaust gas and coolant.

[0048] The controller 50 can store the method for controlling the vehicle's coolant, which will be described below, as logic, and control the flow of coolant according to conditions.

[0049] The detailed description of controller 50 has been omitted.

[0050] Reference Figure 5The flowchart of the method for controlling the coolant of a vehicle according to an embodiment of the present disclosure may include: a first external air temperature comparison step (S110), wherein the controller 50 can compare the temperature of the external air with preset reference temperatures (TA_H) and (TA_L) to identify which of the ATF heater 23 and heater 24 the coolant discharged from the engine 10 should be circulated to, and determine the time to stop the heat exchange between the coolant and the waste heat recovery system 25; circulation steps (S121), (S131), (S141), wherein based on the external air temperature, the controller 50 can control the supply of coolant discharged from the waste heat recovery system 25 to the ATF heater 23 or heater 24; exhaust heat recovery steps (S122), (S132), (S141), (S152 ... S142), wherein the controller 50 can control the supply of coolant discharged from the engine 10 to the waste heat recovery system 25; water temperature comparison steps (S123)(S133)(S143), wherein the controller 50 can identify whether the temperature of the coolant discharged from the waste heat recovery system 25 exceeds the bypass temperature (TW1), (TW2) or (TW3), the bypass temperature (TW1), (TW2) or (TW3) is set to allow the coolant to bypass the waste heat recovery system 25; and bypass steps (S124), (S134), (S144), wherein when the temperature of the coolant exceeds the bypass temperature (TW1), (TW2) or (TW3), the controller 50 can allow the exhaust gas to bypass the coolant, thereby allowing the exhaust gas to flow through the waste heat recovery system 25. In the bypass steps (S124), (S134), and (S144), the controller 50 can operate the drive motor 25c of the waste heat recovery system 25 to allow the exhaust gas to flow and bypass the coolant through the waste heat recovery system 25.

[0051] The method of controlling the vehicle's coolant can be performed by the aforementioned system for controlling the vehicle's coolant.

[0052] For example, based on pre-stored logic, the controller 50 can control the circulation of coolant from the waste heat recovery system 25 to the ATF heater 23 or heater 24 according to the outside air temperature, and stop the heat exchange between the exhaust gas and the coolant.

[0053] The first external air temperature comparison step (S110) may include the controller 50 comparing the external air temperature with preset reference temperatures (TA_H) and (TA_L) to identify the circulation position of the coolant discharged from the engine 10 between the ATF heater 23 and the heater 24, and to determine the time to stop the heat exchange between the coolant and the waste heat recovery system 25.

[0054] Depending on the outside air temperature, the priority of supplying heated coolant in the ATF heater 23 and heater 24 may differ. The first outside air temperature comparison step (S110) may include identifying which of the ATF heater 23 and heater 24 the coolant discharged from the engine 10 is circulated to. Therefore, in the first outside air temperature comparison step (S110), the temperature of the outside air can be compared with reference temperatures (TA_H) and (TA_L).

[0055] As the outside air temperature rises, the coolant temperature rises more rapidly, thus shortening the time required to reach the boiling point. Therefore, to prevent the waste heat recovery system 25 from overheating, the time for stopping heat exchange between the waste gas and the coolant in the waste heat recovery system 25 can be determined. In this regard, in the first outside air temperature comparison step (S110), the outside air temperature can be compared with reference temperatures (TA_H) and (TA_L).

[0056] In the first external air temperature comparison step (S110), the controller 50 can identify whether the external air temperature is equal to or higher than the high temperature reference temperature (TA_H), equal to or lower than the low temperature reference temperature (TA_L), or lower than the high temperature reference temperature (TA_H) and higher than the low temperature reference temperature (TA_L). The high temperature reference temperature (TA_H) can be set or selected to identify the external air temperature as high temperature, and the low temperature reference temperature (TA_L) can be set or selected to identify the external air temperature as low temperature and the low temperature reference temperature (TA_L) is lower than the high temperature reference temperature (TA_H). If the external air temperature is lower than the high temperature reference temperature (TA_H) and higher than the low temperature reference temperature (TA_L), the external air temperature can be identified as room temperature.

[0057] For example, the high temperature reference temperature (TA_H) can be set to 35°C, and the low temperature reference temperature (TA_L) can be set to 10°C.

[0058] Therefore, refer to Figure 5 Furthermore, considering the exemplary embodiment, when the external air temperature is 35°C or higher in the first external air temperature comparison step (S110), steps S121 to S124 are executed; when the external air temperature is lower than 35°C but higher than 10°C, steps S131 to S134 are executed; or when the external air temperature is 10°C or lower, steps S141 to S144 are executed.

[0059] The circulation steps (S121), (S131), and (S141) may include the controller 50 ensuring that the coolant discharged from the waste heat recovery system 25 is supplied to the ATF heater 23 or heater 24 based on the temperature of the outside air in the first outside air temperature comparison step (S110).

[0060] The exhaust heat recovery steps (S122), (S132), and (S142) may include supplying coolant discharged from the engine 10 to the waste heat recovery system 25. The coolant discharged from the engine 10 may flow through the waste heat recovery system 25 and then be returned to the engine 10. In this way, as the coolant circulates between the engine 10 and the waste heat recovery system 25, the heat in the exhaust gas can be used to preheat the engine 10.

[0061] The water temperature comparison steps (S123), (S133), and (S143) may include the controller 50 identifying whether the temperature of the coolant discharged from the waste heat recovery system 25 exceeds the bypass temperature (TW1), (TW2), or (TW3), which may be set or selected to allow the coolant to bypass the waste heat recovery system 25.

[0062] The bypass temperature (TW1), (TW2), or (TW3) can be set to decrease as the outside air temperature increases.

[0063] When the outside air temperature is equal to or higher than the high temperature reference temperature (TA_H), the bypass temperature (TW1), (TW2), or (TW3) can be set to the selected or predetermined high temperature bypass temperature (TW1); when the outside air temperature is equal to or lower than the low temperature reference temperature (TA_L), the bypass temperature (TW1), (TW2), or (TW3) can be set to the selected or predetermined low temperature bypass temperature (TW3); and when the outside air temperature is lower than the high temperature reference temperature (TA_H) but higher than the low temperature reference temperature (TA_L), the bypass temperature (TW1), (TW2), or (TW3) can be set to the selected or predetermined room temperature bypass temperature (TW2).

[0064] As the outside air temperature rises, the coolant reaches its boiling point more quickly. Therefore, the room temperature bypass temperature (TW2) can be set higher than the high temperature bypass temperature (TW1), and the low temperature bypass temperature (TW3) can be set higher than the room temperature bypass temperature (TW2).

[0065] As an example, the high-temperature bypass temperature (TW1), the room-temperature bypass temperature (TW2), and the low-temperature bypass temperature (TW3) can be set to 80°C, 90°C, and 100°C, respectively.

[0066] The bypass steps (S124), (S134), and (S144) may include the controller 50 ensuring that heat exchange between the exhaust gas and the coolant stops when the coolant temperature exceeds the bypass temperature (TW1), (TW2), or (TW3). In this example case, the controller 50 may allow the exhaust gas to bypass the coolant and flow through the waste heat recovery system 25.

[0067] In this example scenario, the controller 50 can operate the drive motor 25c of the waste heat recovery system 25, causing the exhaust gas to bypass the coolant and flow through the waste heat recovery system 25.

[0068] Based on the external air temperature in the first external air temperature comparison step (S110), the loop steps (S121), (S131), (S141) to the bypass steps (S124), (S134), (S144) can be executed in the following manner.

[0069] First, the following will describe the case where the external air temperature is equal to or higher than the high temperature reference temperature (TA_H) in the first external air temperature comparison step (S110).

[0070] If the outside air temperature is equal to or higher than the high-temperature reference temperature (TA_H), then in the cycle steps (S121), (S131), and (S141), the first cycle step (S121) can be executed, in which the controller 50 can direct the coolant to the ATF heater 23. When the outside air temperature is high, there is no heating requirement for the vehicle's interior. Therefore, the coolant discharged from the waste heat recovery system 25 can flow to the ATF heater 23, thereby rapidly preheating the transmission fluid.

[0071] In the first cycle step (S121), the controller 50 can perform the following control.

[0072] The controller 50 can prevent coolant from flowing from the engine 10 to the outside. For example, when the integrated flow control valve 30 is set to control the flow of coolant discharged from the engine 10, the controller 50 can control the integrated flow control valve 30 to be in a flow-stopped state. That is, the controller 50 can control the integrated flow control valve 30 to ensure that coolant does not flow from the integrated flow control valve 30 through the first branch pipe 43, the second branch pipe 44, and the third branch pipe 45 by closing all outlets of the integrated flow control valve 30.

[0073] The controller 50 can control the drive motor 25c of the waste heat recovery system 25 to ensure that the exhaust gas exchanges heat with the coolant and is then discharged from the waste heat recovery system 25. That is, after the exhaust gas exchanges heat with the coolant in the waste heat recovery system 25, the controller 50 can operate the drive motor 25c to close the bypass valve of the waste heat recovery system 25, thereby discharging the exhaust gas to the outside. The first switching valve 23a can be opened, and the second switching valve 24a can be closed.

[0074] Next, refer to Figures 2A to 4 The following will describe various states of the systems and methods according to some embodiments of the present disclosure during use.

[0075] Therefore, as Figure 2A As shown, the coolant circulates through the waste heat recovery system 25 and the ATF heater 23. After being heated in the waste heat recovery system 25, the coolant heats the transmission oil in the ATF heater 23.

[0076] Subsequently, in the exhaust heat recovery steps (S122), (S132), and (S142), when the external air temperature is high, that is, when the external air temperature is equal to or higher than the high temperature reference temperature (TA_H), the first exhaust heat recovery step (S122) is performed, wherein the controller 50 causes the coolant discharged from the engine 10 to be introduced into the exhaust heat recovery system 25.

[0077] The first exhaust heat recovery step (S122) includes heat exchange between exhaust gas and coolant in the waste heat recovery system 25, while the coolant discharged from the engine 10 circulates between the engine 10 and the waste heat recovery system 25. Therefore, the engine 10 can absorb heat from the waste heat recovery system 25, thereby accelerating the preheating of the engine 10.

[0078] In this case, as in the first cycle step (S121), while controlling the drive motor 25c and the first switching valve 23a, the controller 50 also additionally controls the flow of coolant through the engine 10 and the waste heat recovery system 25 (see...). Figure 2B ).

[0079] When the integrated flow control valve 30 is set, the controller 50 can control the integrated flow control valve 30 to allow coolant to flow from the engine 10 through the ATF heater 23 to the waste heat recovery system 25.

[0080] In the water temperature comparison steps (S123), (S133), and (S143), when the outside air temperature is high, the first water temperature comparison step (S123) is executed, wherein the controller 50 identifies whether the temperature of the coolant discharged from the waste heat recovery system 25 exceeds the high temperature bypass temperature, which is set to bypass the waste heat recovery system 25 under high temperature conditions.

[0081] When the outside air temperature is high, that is, when the outside air temperature is equal to or higher than the high temperature reference temperature (TA_H) by 35°C, the high temperature bypass temperature (TW1) can be set to 80°C. Therefore, the first water temperature comparison step (S123) can identify whether the temperature of the coolant discharged from the waste heat recovery system 25 exceeds 80°C.

[0082] When the coolant temperature exceeds the high-temperature bypass temperature (TW1), the first bypass step (S124) is executed, wherein the controller 50 operates the drive motor 25c to allow the coolant to bypass the waste heat recovery system 25.

[0083] In the first bypass step (S124), when the outside air temperature is equal to or higher than the high temperature reference temperature (TA_H) and the coolant temperature in the waste heat recovery system 25 exceeds the high temperature bypass temperature (TW1), the controller 50 allows the exhaust gas to pass through the waste heat recovery system 25, thereby stopping the heat exchange between the exhaust gas and the coolant in the waste heat recovery system 25 to prevent the coolant in the waste heat recovery system 25 from reaching the boiling point.

[0084] Specifically, in the first bypass step (S124), the controller 50 operates the drive motor 25c to allow the exhaust gas to flow through the waste heat recovery system 25 without exchanging heat with the coolant inside the system. When the bypass valve installed in the waste heat recovery system 25 is closed, the exhaust gas flows through after exchanging heat with the coolant. However, when the bypass valve is open, the exhaust gas flows through without exchanging heat with the coolant. In the first bypass step (S124), the controller 50 controls the drive motor 25c to open the bypass valve.

[0085] If the temperature of the coolant discharged from the waste heat recovery system 25 does not exceed the high temperature bypass temperature (TW1) in the first water temperature comparison step (S123), the first waste gas heat recovery step (S122) is repeated.

[0086] Second, the following describes the case in the first external air temperature comparison step (S110) where the external air temperature is lower than the high temperature reference temperature (TA_H) but higher than the low temperature reference temperature (TA_L).

[0087] Even if the outside air temperature is lower than the high temperature reference temperature (TA_H) but higher than the low temperature reference temperature (TA_L) (i.e., room temperature), the loop steps (S121), (S131), (S141) to the bypass steps (S124), (S134), (S144) are executed in a similar manner as when the outside air temperature exceeds the high temperature reference temperature (TA_H).

[0088] In other words, when the external air temperature is lower than the high temperature reference temperature (TA_H) but higher than the low temperature reference temperature (TA_L), the cycle steps (S121), (S131), (S141) to the bypass steps (S124), (S134), (S144) will be executed as the second cycle step (S131), the second waste gas heat recovery step (S132), the second water temperature comparison step (S133), and the second bypass step (S134), respectively.

[0089] In this configuration, the second cycle step (S131), the second waste gas heat recovery step (S132), and the second bypass step (S134) are controlled by the controller 50 in a manner similar to that of the first cycle step (S121), the first waste gas heat recovery step (S122), and the first bypass step (S124). However, in the second water temperature comparison step (S133), the controller 50 sets the reference temperature, i.e., the room temperature bypass temperature (TW2), to be different from the high temperature bypass temperature (TW1).

[0090] When the outside air temperature is room temperature, the second cycle step (S131) ​​of the cycle steps (S121), (S131), and (S141) is executed, in which the controller 50 directs the coolant to the ATF heater 23. Even when the outside air temperature is room temperature, there is no heating requirement for the vehicle's interior. Therefore, the coolant discharged from the waste heat recovery system 25 flows to the ATF heater 23, thereby heating the transmission fluid.

[0091] In the second cycle step (S131), the controller 50 performs the following control.

[0092] The controller 50 controls the coolant to prevent it from flowing from the engine 10 to the outside. Similar to the first cycle step (S121), when the integrated flow control valve 30 is set, the controller 50 controls the integrated flow control valve 30 to be in a flow-stopped state, thereby ensuring that all outlets of the integrated flow control valve 30 are closed.

[0093] Additionally, the controller 50 controls the drive motor 25c of the waste heat recovery system 25 to ensure that the exhaust gas exchanges heat with the coolant and is then discharged into the waste heat recovery system 25. The controller also opens the first switching valve 23a and closes the second switching valve 24a.

[0094] like Figure 2A As shown, the coolant circulates through the waste heat recovery system 25 and the ATF heater 23, thereby heating the transmission oil in the ATF heater 23.

[0095] Subsequently, in the exhaust heat recovery steps (S122), (S132), and (S142), when the temperature of the outside air is room temperature, the second exhaust heat recovery step (S132) is performed, wherein the controller 50 causes the coolant discharged from the engine 10 to be introduced into the exhaust heat recovery system 25.

[0096] The second exhaust heat recovery step (S132) also includes heat exchange between the exhaust gas and the coolant in the waste heat recovery system 25, while the coolant discharged from the engine 10 circulates between the engine 10 and the waste heat recovery system 25.

[0097] In this case, as in the first cycle step (S121), while controlling the drive motor 25c and the first switching valve 23a, the controller 50 also additionally controls the flow of coolant through the engine 10 and the waste heat recovery system 25 (see...). Figure 2B ).

[0098] When the integrated flow control valve 30 is set, the controller 50 can control the integrated flow control valve 30 to allow coolant to flow from the engine 10 through the ATF heater 23 to the waste heat recovery system 25.

[0099] In the water temperature comparison steps (S123), (S133), and (S143), when the external air temperature is room temperature, the second water temperature comparison step (S123) is executed, wherein the controller 50 identifies whether the temperature of the coolant discharged from the waste heat recovery system 25 exceeds the room temperature bypass temperature (TW2), which is set to bypass the waste heat recovery system 25 at room temperature.

[0100] When the outside air temperature is room temperature, that is, when the outside air temperature is 35°C lower than the high temperature reference temperature (TA_H) and 10°C higher than the low temperature reference temperature (TA_L), the room temperature bypass temperature (TW2) can be set to 90°C. Therefore, the second water temperature comparison step (S133) can identify whether the temperature of the coolant discharged from the waste heat recovery system 25 exceeds 90°C.

[0101] When the outside air temperature is room temperature, the time required for the coolant to reach its boiling point is longer than when the outside air temperature is higher. Therefore, the room temperature bypass temperature (TW2) can be set higher than the high temperature bypass temperature (TW1).

[0102] When the coolant temperature exceeds the room temperature bypass temperature (TW2), a second bypass step (S134) is performed, in which the controller 50 operates the drive motor 25c to allow the coolant to bypass the waste heat recovery system 25.

[0103] In the second bypass step (S134), when the outside air temperature is lower than the high temperature reference temperature (TA_H) but higher than the low temperature reference temperature (TA_L) and the coolant temperature in the waste heat recovery system 25 exceeds the room temperature bypass temperature (TW2), the controller 50 causes the exhaust gas to bypass the waste heat recovery system 25, thereby stopping the heat exchange between the exhaust gas and the coolant in the waste heat recovery system 25 to prevent the coolant in the waste heat recovery system 25 from reaching the boiling point.

[0104] In other words, in the second bypass step (S134), the controller 50 operates the drive motor 25c to allow the exhaust gas to flow through the waste heat recovery system 25 without exchanging heat with the coolant inside the waste heat recovery system 25. That is, the controller 50 controls the drive motor 25c to open the bypass valve.

[0105] Even in the second water temperature comparison step (S133), if the temperature of the coolant discharged from the waste heat recovery system 25 does not exceed the room temperature bypass temperature (TW2), the second waste gas heat recovery step (S132) is repeated.

[0106] Furthermore, the case where the external air temperature is equal to or lower than the low temperature reference temperature (TA_L) in the first external air temperature comparison step (S110) will be described below.

[0107] When the outside air temperature is equal to or lower than the low-temperature reference temperature (TA_L), the third cycle step (S141) of the cycle steps (S121), (S131), and (S141) is executed, in which the controller 50 directs the coolant to the heater 24. When the outside air temperature is low, there is a heating demand inside the vehicle. Therefore, the coolant discharged from the waste heat recovery system 25 flows to the heater 24, thereby heating the air supplied to the vehicle interior and raising the temperature of the passenger compartment.

[0108] In the third cycle step (S141), the controller 50 performs the following control.

[0109] The controller 50 controls the flow of coolant from the engine 10 to the outside. For example, when the integrated flow control valve 30 is set to control the flow of coolant discharged from the engine 10, the controller 50 controls the integrated flow control valve 30 to be in a flow-stopped state. That is, the controller 50 controls the integrated flow control valve 30 to ensure that coolant does not flow from the integrated flow control valve 30 through the first branch line 43, the second branch line 44, and the third branch line 45 by closing all outlets of the integrated flow control valve 30.

[0110] Additionally, controller 50 controls drive motor 25c of waste heat recovery system 25 to ensure that exhaust gas exchanges heat with coolant and is then discharged from waste heat recovery system 25. Drive motor 25c closes bypass valve of waste heat recovery system 25, allowing exhaust gas to exchange heat with coolant within waste heat recovery system 25 before discharge. Furthermore, first switching valve 23a is closed, and second switching valve 24a is open.

[0111] Thus, the coolant circulates through the waste heat recovery system 25 and the heater 24, such as Figure 3A As shown. After being heated in the waste heat recovery system 25, the coolant flows through the heater 24, thereby heating the air introduced into the vehicle, thus raising the temperature of the vehicle's cabin.

[0112] Subsequently, in the exhaust heat recovery steps (S122), (S132), and (S142), when the temperature of the outside air is low, the third exhaust heat recovery step (S142) is performed, wherein the controller 50 causes the coolant discharged from the engine 10 to be introduced into the exhaust heat recovery system 25.

[0113] The third exhaust heat recovery step (S142) includes heat exchange between the exhaust gas and the coolant in the waste heat recovery system 25, while the coolant discharged from the engine 10 circulates between the engine 10 and the waste heat recovery system 25. Therefore, the engine 10 can absorb heat from the waste heat recovery system 25, thereby accelerating the preheating of the engine 10 in low-temperature environments.

[0114] In this case, as in the third cycle step (S141), while controlling the drive motor 25c and the second switching valve 24a, the controller 50 also additionally controls the flow of coolant through the engine 10 and the waste heat recovery system 25 (see...). Figure 3B ).

[0115] When the integrated flow control valve 30 is set, the controller 50 can control the integrated flow control valve 30 to allow coolant to flow from the engine 10 through the heater 24 to the waste heat recovery system 25.

[0116] In the water temperature comparison steps (S123), (S133), and (S143), when the temperature of the outside air is low, the third water temperature comparison step (S143) is executed, wherein the controller 50 identifies whether the temperature of the coolant discharged from the waste heat recovery system 25 exceeds the low temperature bypass temperature, which is set to bypass the waste heat recovery system 25 under low temperature conditions.

[0117] When the outside air temperature is low, i.e., when the outside air temperature is equal to or lower than the low temperature reference temperature (TA_L) by 10°C, the low temperature bypass temperature (TW3) can be set to 100°C. Therefore, the third water temperature comparison step (S143) can identify whether the temperature of the coolant discharged from the waste heat recovery system 25 exceeds 100°C.

[0118] In particular, when the outside air temperature is low, it takes longer for the coolant to reach its boiling point than at high temperatures or room temperature. Therefore, the low-temperature bypass temperature (TW3) is set higher than the high-temperature bypass temperature (TW1) or the room-temperature bypass temperature (TW2).

[0119] When the coolant temperature exceeds the low-temperature bypass temperature (TW3), the third bypass step (S144) is executed, in which the controller 50 operates the drive motor 25c to allow the coolant to bypass the waste heat recovery system 25.

[0120] In the third bypass step (S144), when the outside air temperature is equal to or higher than the low temperature reference temperature (TA_L) and the coolant temperature in the waste heat recovery system 25 exceeds the low temperature bypass temperature (TW3), the controller 50 causes the exhaust gas to bypass the waste heat recovery system 25, thereby stopping the heat exchange between the exhaust gas and the coolant in the waste heat recovery system 25 to prevent the coolant in the waste heat recovery system 25 from reaching the boiling point.

[0121] In other words, in the third bypass step (S144), the controller 50 operates the drive motor 25c to allow the exhaust gas to flow through the waste heat recovery system 25 without exchanging heat with the coolant inside the system. The controller 50 controls the drive motor 25c to open the bypass valve installed in the waste heat recovery system 25.

[0122] In the third water temperature comparison step (S143), when the temperature of the coolant discharged from the waste heat recovery system 25 does not exceed the low temperature bypass temperature (TW3), the third waste gas heat recovery step (S142) is repeated.

[0123] Figure 6A and Figure 6B A method for controlling the coolant of a vehicle according to an embodiment of the present disclosure is shown.

[0124] Reference Figure 6A and Figure 6BThe method for controlling the coolant of a vehicle according to this example embodiment may include: a second external air temperature comparison step (S210), wherein the controller 50 can compare the external air temperature with a preset reference temperature (TA_L) to determine the operating mode of the waste heat recovery system 25 and the integrated flow control valve 30; mode activation steps (S221) and (S231), wherein based on the external air temperature, the controller 50 can cause the integrated flow control valve 30 to enter a set, selected, or predetermined operating mode; bypass identification steps (S222) and (S232), wherein the controller 50 can identify whether exhaust gas flows through the waste heat recovery system 25 without exchanging heat with the coolant; and flow stop identification steps (S223) and (S233), wherein the controller 150 identifies whether the integrated flow control valve is controlled in a flow stop state; flow stop release steps (S225) and (S235), wherein the controller 50 can control the release of the flow stop control of the integrated flow control valve 30; water temperature condition comparison steps (S226) and (S236), wherein the controller 50 can identify whether the coolant temperature discharged from the waste heat recovery system 25 is lower than the recovery start temperature when the coolant temperature discharged from the waste heat recovery system 25 exceeds the coolant temperature discharged from the engine 10; and waste heat recovery start steps (S227) and (S237), wherein the controller 50 can control the waste heat recovery system 25 to recover waste heat.

[0125] The second external air temperature comparison step (S210) may include the controller 50 comparing the external air temperature with a preset reference temperature (TA_L) to determine the operating mode of the waste heat recovery system 25 and the integrated flow control valve 30.

[0126] Even in this example embodiment, since the control of the waste heat recovery system 25 and the integrated flow control valve 30 can vary according to the outside air temperature, the outside air temperature can be compared with the reference temperature (TA_L) first.

[0127] The mode start-up steps (S221) and (S231) may include the controller 50 causing the integrated flow control valve 30 to enter a selected or predetermined operating mode based on the external air temperature.

[0128] The bypass identification steps (S222) and (S232) may include the controller 50 identifying whether exhaust gas flows through the waste heat recovery system 25 without exchanging heat with the coolant. The waste heat recovery system 25 may be a structure that allows heat exchange between the exhaust gas and the coolant, thereby transferring heat from the exhaust gas to the coolant. However, depending on the vehicle's operating conditions, the exhaust gas may bypass the coolant and be discharged directly without heat exchange with it. In the bypass identification steps (S222) and (S232), the controller 50 may identify whether the waste heat recovery system 25 is in a bypass state.

[0129] The flow stop identification steps (S223) and (S233) may include the controller 50 identifying whether the integrated flow control valve 30 is controlled in a flow stop state. That is, the controller 50 may close the integrated flow control valve 30 while the coolant is still in the engine 10, thereby preventing the coolant from circulating from the engine 10 to the ATF heater 23, heater 24 and radiator 26, thereby accelerating the preheating of the engine 10.

[0130] However, a portion of the coolant can circulate through the engine 10 and the EGR cooler 22.

[0131] The flow stop release steps (S225) and (S235) may include the controller 50 releasing the flow stop control of the integrated flow control valve 30.

[0132] The controller 50 can deactivate the flow stop control of the integrated flow control valve 30, thereby allowing a portion of the coolant to flow into the waste heat recovery system 25.

[0133] The water temperature condition comparison steps (S226) and (S236) may include the controller 50 identifying whether the coolant temperature discharged from the waste heat recovery system 25 is lower than the recovery start temperature when the coolant temperature discharged from the waste heat recovery system 25 exceeds the coolant temperature discharged from the engine 10. The recovery start temperature may be preset to trigger the exhaust gas heat recovery control entering the waste heat recovery system 25.

[0134] The water temperature condition comparison steps (S226) and (S236) can be performed to identify whether the coolant can be allowed to flow from the engine 10 to the waste heat recovery system 25 through the flow stop release steps (S225) and (S235), so that the engine 10 can absorb heat from the waste heat recovery system 25.

[0135] In other words, when the engine 10 is not fully preheated, the coolant can absorb heat from the exhaust gas through the waste heat recovery system 25 and transfer the heat to the engine 10, thereby accelerating the preheating of the engine 10.

[0136] However, when the coolant temperature in the waste heat recovery system 25 is equal to or higher than the recovery start-up temperature, the coolant may be in an overheated or near-overheated state. In this case, the coolant circulating through the engine 10 and the waste heat recovery system 25 can then dissipate the heat into the atmosphere.

[0137] Therefore, through the water temperature condition comparison steps (S226) and (S236), the controller can compare the coolant temperature discharged from the waste heat recovery system 25 with the coolant temperature discharged from the engine 10, and identify whether the coolant temperature discharged from the waste heat recovery system 25 is lower than the recovery start temperature.

[0138] The recovery start-up temperature can be set to 100°C. That is, the condition for recovering exhaust heat from the waste heat recovery system 25 and transferring it to the engine 10 can be limited to the temperature of the coolant discharged from the waste heat recovery system 25 being equal to or lower than its boiling point.

[0139] The waste heat recovery start-up steps (S227) and (S237) may include controller 50 controlling waste heat recovery system 25 to recover waste heat.

[0140] The waste heat recovery start-up steps (S227) and (S237) may include the controller 50 controlling the drive motor 25c installed in the waste heat recovery system 25 to ensure that the waste gas flowing through the waste heat recovery system 25 exchanges heat with the coolant flowing through the waste heat recovery system 25.

[0141] The waste heat recovery system 25 may be equipped with a bypass valve that determines the flow direction of the waste gas. The bypass valve may be operated by a drive motor 25c, which may be located on one side of the waste heat recovery system 25.

[0142] In the waste gas heat recovery start-up steps (S227) and (S237), the controller 50 can operate the drive motor 25c to ensure that the waste gas exchanges heat with the coolant under the control of the bypass valve and is discharged.

[0143] Therefore, the coolant can absorb heat from the exhaust gas in the waste heat recovery system 25. Because the coolant can circulate between the engine 10 and the waste heat recovery system 25, the heat absorbed from the waste heat recovery system 25 can be transferred to the engine 10, thereby accelerating the preheating of the engine 10.

[0144] In the method for controlling the coolant of a vehicle according to this example embodiment, based on the external air temperature in the second external air temperature comparison step (S210), the mode start step (S221), (S231) to the exhaust heat recovery start step (S227), (S237) can be performed as follows.

[0145] The second external air temperature comparison step (S210) may include the controller 50 identifying whether the external air temperature exceeds or is lower than or equal to a preset low temperature reference temperature (TA_L) to identify the external air temperature as low temperature.

[0146] In this example embodiment, the temperature of the outside air can be categorized as room temperature and low temperature for different control operations. Controller 50 can identify whether the temperature of the outside air exceeds, is lower than, or is equal to a low-temperature reference temperature (TA_L) used as a reference.

[0147] First, when the temperature of the outside air exceeds the low temperature reference temperature (TA_L), the controller 50 can perform the following control.

[0148] When the outside air temperature exceeds the low temperature reference temperature (TA_L), the room temperature mode start-up step (S221) in the mode start-up steps (S221) and (S231) can be executed. This room temperature mode start-up step can start controlling the waste heat recovery system 25 and the integrated flow control valve 30 to be in room temperature mode.

[0149] The room temperature mode start-up step (S221) may include controller 50 controlling the circulation of coolant between ATF heater 23 and waste heat recovery system 25.

[0150] The bypass identification steps (S222) (S232) may include the controller 50 performing the first bypass identification step (S222) to identify the state of the waste heat recovery system 25. That is, the first bypass identification step (S222) can identify whether, in room temperature mode, the exhaust gas bypasses and flows directly through the waste heat recovery system 25 without exchanging heat with the coolant.

[0151] In a room temperature environment, the first flow stop step (S223) in the flow stop identification step (S223) (S233) can be executed, wherein the controller 50 can identify whether the integrated flow control valve 30 is controlled to be in a flow stop state in the room temperature mode.

[0152] Through the first bypass identification step (S222) and the first flow stop identification step (S223), the controller 50 can identify whether the temperature of the coolant in the waste heat recovery system 25 is in a heated state due to the continuous flow of waste gas through the waste heat recovery system 25 without coolant circulation at room temperature.

[0153] When the exhaust gas and coolant are in a heat exchange state during the first bypass identification step (S222), the process can return to the room temperature mode start-up step (S221). When the integrated flow control valve 30 is not controlled and is in a flow stop state during the first flow stop identification step (S223), the controller 50 can maintain the current state and continue to control the integrated flow control valve 30 accordingly (S224).

[0154] In the first flow stop identification step (S223), when the controller 50 identifies that the integrated flow control valve 30 is being controlled to a flow stop state, the controller 50 can execute the first flow stop release step (S225) to release the flow stop control of the integrated flow control valve 30 in room temperature mode.

[0155] The first flow stop release step (S225) may include the controller 50 controlling the flow of coolant from the engine 10 to the waste heat recovery system 25 through the integrated flow control valve 30. For example, the flow stop may be released by allowing coolant to flow from the integrated flow control valve 30 to the ATF heater 23.

[0156] Therefore, when the flow cessation is lifted, the coolant can circulate through the engine 10 and the waste heat recovery system 25, thereby allowing heat to be transferred from the waste heat recovery system 25 to the engine 10.

[0157] In a room temperature environment, the first water temperature condition comparison step (S226) in the water temperature condition comparison step (S226) (S236) can be executed. In this step, the controller 50 identifies whether the coolant temperature discharged from the waste heat recovery system 25 is lower than the recovery start temperature when the coolant temperature discharged from the waste heat recovery system 25 exceeds the coolant temperature discharged from the engine 10. The recovery start temperature is preset to trigger the exhaust gas heat recovery control entering the waste heat recovery system 25.

[0158] After heat is transferred to the waste heat recovery system 25 via the first flow stop release step (S225), a first water temperature condition comparison step (S226) can be performed to identify whether additional heat can be transferred from the waste heat recovery system 25 to the engine 10.

[0159] If the temperature of the coolant discharged from the waste heat recovery system 25 exceeds the temperature of the coolant discharged from the engine 10, the engine 10 can be in a state where it can absorb additional heat from the waste heat recovery system 25. Specifically, because the temperature of the coolant on the waste heat recovery system 25 side is lower than the recovery start-up temperature, a stable state can be maintained even if heat transfer occurs from the waste heat recovery system 25 to the engine 10. The recovery start-up temperature can be set to 100°C. Because the temperature of the coolant on the waste heat recovery system 25 side exceeds the temperature of the coolant in the engine 10, but is still below its boiling point, the coolant discharged from the waste heat recovery system 25 does not dissipate heat to the outside for cooling. Instead, the heat is transferred to the engine 10.

[0160] When the conditions of the first water temperature comparison step (S226) are met, the first exhaust heat recovery start-up step (S227) can be executed, wherein the controller 50 can start controlling the waste heat recovery system 25 to be in a state where heat exchange can be performed at room temperature. The controller 50 can operate the drive motor 25c to ensure that the exhaust gas passes through the coolant side of the waste heat recovery system 25 and is discharged to the outside, thereby transferring the heat in the waste heat recovery system 25 to the engine 10.

[0161] If the conditions of the first water temperature condition comparison step (S226) are not met, the controller 50 may continue to control the integrated flow control valve 30 to remain in the current state (S228).

[0162] Furthermore, when the temperature of the outside air is lower than the low-temperature reference temperature (TA_L), the controller can perform the following control.

[0163] When the outside air temperature is lower than the low temperature reference temperature (TA_L), the low temperature mode start-up step (S231) in the mode start-up steps (S221) and (S231) can be executed. The low temperature mode start-up step (S231) can start controlling the waste heat recovery system 25 and the integrated flow control valve 30 to be in low temperature mode.

[0164] The low-temperature mode start-up step (S231) may include controller 50 controlling the circulation of coolant between heater 24 and waste heat recovery system 25.

[0165] In a low-temperature environment, the second bypass identification step (S232) in the bypass identification steps (S222) and (S232) can be executed, wherein the controller 50 can identify the state of the waste heat recovery system 25. That is, the second bypass identification step (S232) can identify whether, in the low-temperature mode, the exhaust gas bypasses the coolant and passes directly through the waste heat recovery system 25 without heat exchange, thus preventing heat exchange.

[0166] In a low-temperature environment, the second flow stop step (S233) in the flow stop identification step (S223) (S233) can be executed, wherein the controller 50 can identify whether the integrated flow control valve 30 is controlled to be in a flow stop state in the room temperature mode.

[0167] In this example embodiment, through the second bypass identification step (S232) and the second flow stop identification step (S233), the controller 50 can identify whether the temperature of the coolant in the waste heat recovery system 25 is in a state of continuous heating due to the continuous flow of waste gas through the waste heat recovery system 25 when the coolant stops circulating in a low temperature environment.

[0168] When the conditions of the second bypass identification step (S232) and the second flow stop identification step (S233) are not met, the process can return to the same low temperature mode start-up step (S231) as the second bypass identification step (S232) and the second flow stop identification step (S233), and the integrated flow control valve 30 is controlled to be in the current state (S234).

[0169] However, in the second flow stop identification step (S233), when the controller 50 identifies that the integrated flow control valve 30 is being controlled to a flow stop state, the controller 50 can execute the second flow stop release step (S235) to release the flow stop control of the integrated flow control valve 30 in the low temperature mode.

[0170] Similar to the first flow stop release step (S225), the second flow stop release step (S235) may include the controller 50 controlling the flow of coolant from the engine 10 to the waste heat recovery system 25 through the integrated flow control valve 30. However, since the outside air temperature is equal to or lower than the cryogenic reference temperature (TA_L), the flow stop can be released by allowing coolant to flow from the integrated flow control valve 30 to the heater 24.

[0171] Therefore, once the flow cessation is lifted, the coolant can circulate through the engine 10 and the waste heat recovery system 25.

[0172] In low-temperature environments, the second water temperature condition comparison step (S236) in the water temperature condition comparison steps (S226) and (S236) can be executed. The second water temperature condition comparison step (S236) can be executed in the same manner as the first water temperature condition comparison step (S226). That is, the controller 50 can identify whether the coolant temperature discharged from the waste heat recovery system 25 is lower than the recovery start temperature when the coolant temperature discharged from the waste heat recovery system 25 exceeds the coolant temperature discharged from the engine 10. This recovery start temperature can be preset to trigger the exhaust gas heat recovery control entering the waste heat recovery system 25. In the second water temperature condition comparison step (S236), the recovery start temperature can be set to the same temperature as in the first water temperature condition comparison step (S226).

[0173] The second water temperature condition comparison step (S236) can also be performed to identify whether the engine 10 can receive additional heat transferred from the waste heat recovery system 25.

[0174] When the conditions of the second water temperature comparison step (S236) are met, the second exhaust heat recovery start-up step (S237) can be executed, wherein the controller 50 can start controlling the exhaust heat recovery system 25 to be in a state where heat exchange can be performed in a low-temperature environment. The controller 50 can operate the drive motor 25c to ensure that exhaust gas passes through the coolant side of the exhaust heat recovery system 25 and is discharged to the outside, thereby transferring the heat in the exhaust heat recovery system 25 to the engine 10.

[0175] If the conditions of the second water temperature condition comparison step (S236) are not met, the controller 50 may continue to control the integrated flow control valve 30 to remain in the current state (S238).

Claims

1. A system of controlling coolant of a vehicle, comprising: an integrated flow control valve that opens and closes branch lines that supply the engine-exhausted coolant of the vehicle to an automatic transmission fluid (ATF) heater, a heater, and a radiator, respectively; a waste heat recovery system that exchanges heat between the exhaust gas exhausted from the engine and the coolant exhausted from the engine; a main water pump that circulates the coolant; a return line that circulates the coolant from the waste heat recovery system to the ATF heater and the heater, respectively, and a controller that: controls the integrated flow control valve to open and close the branch lines to supply the coolant from the integrated flow control valve to the ATF heater, the heater, and the radiator, respectively, in accordance with a temperature of outside air, a temperature of the engine-exhausted coolant, and a temperature of the coolant exhausted from the waste heat recovery system, controls the waste heat recovery system to allow heat exchange between the exhaust gas and the coolant, and controls the coolant to be circulated from the waste heat recovery system to the ATF heater or the heater, based on the temperature of the outside air.

2. The system according to claim 1, wherein: the waste heat recovery system includes a drive motor that operates the waste heat recovery system to exchange heat between the exhaust gas and the coolant or to allow the exhaust gas to pass through the waste heat recovery system with reduced heat exchange or without heat exchange with the coolant; and the controller controls the drive motor.

3. The system of claim 2, wherein, the controller determines whether the temperature of the outside air is equal to or higher than a high-temperature reference temperature, and if so, determines that the temperature of the outside air is high; determines whether the temperature of the outside air is equal to or lower than a low-temperature reference temperature, which is lower than the high-temperature reference temperature, or determines that the temperature of the outside air is lower than the high-temperature reference temperature and higher than the low-temperature reference temperature, to determine that the temperature of the outside air is room temperature; based on the temperature of the outside air exceeding the low-temperature reference temperature, the controller controls the drive motor to allow the exhaust gas and the coolant to flow and exchange heat in the waste heat recovery system, thereby circulating the coolant between the waste heat recovery system and the ATF heater; and based on the temperature of the outside air being equal to or lower than the low-temperature reference temperature, the controller controls the drive motor to allow the exhaust gas and the coolant to flow and exchange heat in the waste heat recovery system, thereby circulating the coolant between the waste heat recovery system and the heater.

4. The system of claim 3, wherein, the controller controls the drive motor to allow the exhaust gas to flow through the waste heat recovery system with reduced heat exchange or without heat exchange with the coolant, based on the temperature of the coolant exhausted from the waste heat recovery system exceeding a bypass reference temperature.

5. The system of claim 2, wherein, The controller determines whether the temperature of the outside air is higher than a low temperature reference temperature or equal to or lower than the low temperature reference temperature, and determines that the temperature of the outside air is low if the temperature of the outside air is equal to or lower than the low temperature reference temperature; and The controller controls the integrated flow control valve to allow the engine-exhaust coolant to flow to the ATF heater based on the temperature of the outside air exceeding the low temperature reference temperature, and controls the integrated flow control valve to allow the engine-exhaust coolant to flow to the heater based on the temperature of the outside air being equal to or lower than the low temperature reference temperature.

6. The system of claim 5, wherein, The controller controls the coolant to flow from the engine to the waste heat recovery system through the integrated flow control valve based on the exhaust gas in the waste heat recovery system flowing with reduced heat exchange or no heat exchange with the coolant and no engine-exhaust coolant being discharged from the integrated flow control valve.

7. The system of claim 6, wherein, The controller controls the drive motor to allow the exhaust gas and the coolant to exchange heat and flow in the waste heat recovery system based on the temperature of the waste heat recovery system-exhaust coolant exceeding the temperature of the engine-exhaust coolant and the temperature of the waste heat recovery system-exhaust coolant being lower than a recovery start temperature.

8. A method of controlling coolant of a vehicle, comprising: a first outside air temperature comparison step of comparing a temperature of outside air with a reference temperature to determine which of an automatic transmission fluid (ATF) heater and a heater an engine-exhaust coolant is circulated to and to determine a time to stop heat exchange between the coolant and a waste heat recovery system; a circulation step of supplying the coolant discharged from the waste heat recovery system to the ATF heater or the heater based on the temperature of the outside air; a waste heat recovery step of supplying the engine-exhaust coolant to the waste heat recovery system; a water temperature comparison step of determining whether a temperature of the waste heat recovery system-exhaust coolant exceeds a bypass temperature to allow the coolant to bypass the waste heat recovery system; and a bypass step of allowing exhaust gas to flow through the waste heat recovery system such that the exhaust gas exchanges heat with the coolant or does not exchange heat with the coolant based on the temperature of the waste heat recovery system-exhaust coolant exceeding the bypass temperature. The first outside air temperature comparison step includes:

9. The method of claim 8, wherein, determining whether the temperature of the outside air is equal to or higher than a high temperature reference temperature set to determine the temperature of the outside air as high temperature; determining whether the temperature of the outside air is equal to or lower than a low temperature reference temperature set to determine the temperature of the outside air as low temperature, the low temperature reference temperature being lower than the high temperature reference temperature; or determining whether the temperature of the outside air is lower than the high temperature reference temperature and higher than the low temperature reference temperature to determine the temperature of the outside air as room temperature. In the first outside air temperature comparison step, based on the temperature of the outside air being equal to or higher than the high temperature reference temperature:

10. The method of claim 9, wherein, ​ performing a first of the circulation steps, the first circulation step including flowing coolant from the waste heat recovery system to the ATF warmer; performing a first of the waste heat recovery steps, the first waste heat recovery step including introducing the engine-exhaust coolant into the waste heat recovery system; performing a first of the water temperature comparison steps, the first water temperature comparison step including determining whether a temperature of the waste heat recovery system-exhaust coolant exceeds a high temperature bypass temperature, the high temperature bypass temperature being set to bypass the waste heat recovery system in a high temperature condition; and performing a first bypass step, the first bypass step including allowing coolant to bypass the waste heat recovery system based on the temperature of the waste heat recovery system coolant exceeding the high temperature bypass temperature.

11. The method of claim 9, wherein, in the first outside air temperature comparison step, based on the temperature of the outside air being room temperature, i.e., below the high temperature reference temperature and above the low temperature reference temperature: performing a second of the circulation steps, the second circulation step including flowing coolant from the waste heat recovery system to the ATF warmer; performing a second of the waste heat recovery steps, the second waste heat recovery step including introducing the engine-exhaust coolant into the waste heat recovery system; performing a second of the water temperature comparison steps, the second water temperature comparison step including determining whether a temperature of the waste heat recovery system-exhaust coolant exceeds a room temperature bypass temperature, the room temperature bypass temperature being set to bypass the waste heat recovery system in a room temperature condition; and performing a second bypass step, the second bypass step including allowing coolant to bypass the waste heat recovery system based on the temperature of the waste heat recovery system coolant exceeding the room temperature bypass temperature.

12. The method of claim 9, wherein, in the first outside air temperature comparison step, based on the temperature of the outside air being equal to or below the low temperature reference temperature: performing a third of the circulation steps, the third circulation step including flowing coolant from the waste heat recovery system to the heater; performing a third of the waste heat recovery steps, the third waste heat recovery step including introducing the engine-exhaust coolant into the waste heat recovery system; performing a third of the water temperature comparison steps, the third water temperature comparison step including determining whether a temperature of the waste heat recovery system-exhaust coolant exceeds a low temperature bypass temperature, the low temperature bypass temperature being set to bypass the waste heat recovery system in a low temperature condition; and performing a third bypass step, the third bypass step including allowing coolant to bypass the waste heat recovery system based on the temperature of the waste heat recovery system coolant exceeding the low temperature bypass temperature.

13. The method of claim 9, wherein, the bypass temperatures are set to decrease as the temperature of the outside air increases.

14. The method of claim 13, wherein, the bypass temperatures are set to: a high temperature bypass temperature, based on the temperature of the outside air being equal to or above the high temperature reference temperature; a low temperature bypass temperature, based on the temperature of the outside air being equal to or below the low temperature reference temperature; and ​ a room temperature bypass temperature, which is set to be higher than the high temperature bypass temperature and lower than the low temperature bypass temperature, the room temperature bypass temperature is set to be higher than the high temperature bypass temperature, and the low temperature bypass temperature is set to be higher than the room temperature bypass temperature.

15. A method of controlling coolant of a vehicle, comprising: a second outside air temperature comparison step of comparing a temperature of outside air with a reference temperature to determine an operation mode of a waste heat recovery system and an integrated flow control valve; a mode initiation step of causing the integrated flow control valve to enter a first operation mode based on the temperature of the outside air; a bypass determination step of determining whether exhaust gas flows through the waste heat recovery system with reduced heat exchange with coolant or without heat exchange; a flow stop determination step of determining whether the integrated flow control valve is controlled to be in a flow stop state; a flow stop release step of releasing flow stop control of the integrated flow control valve; a water temperature condition comparison step of determining whether a temperature of coolant discharged from the waste heat recovery system is lower than a recovery initiation temperature, which is preset to trigger waste heat recovery control in the waste heat recovery system, in a case where the temperature of the coolant discharged from the waste heat recovery system exceeds a temperature of coolant discharged from an engine; and a waste heat recovery initiation step of controlling the waste heat recovery system to recover waste heat.

16. The method of claim 15, wherein, the waste heat recovery initiation step includes controlling a drive motor provided in the waste heat recovery system such that exhaust gas passing through the waste heat recovery system exchanges heat with coolant passing through the waste heat recovery system.

17. The method of claim 15, wherein, the second outside air temperature comparison step includes determining whether the temperature of the outside air is higher than a low temperature reference temperature or equal to or lower than the low temperature reference temperature, the low temperature reference temperature being preset to determine the temperature of the outside air as low temperature.

18. The method of claim 17, wherein, in the second outside air temperature comparison step, based on the temperature of the outside air exceeding the low temperature reference temperature: a room temperature mode initiation step in the mode initiation step is executed, the room temperature mode initiation step including starting control of the waste heat recovery system and the integrated flow control valve in a room temperature mode; a first bypass determination step in the bypass determination step is executed, the first bypass determination step including determining whether the exhaust gas passes through the waste heat recovery system with reduced heat exchange with coolant or without heat exchange in the room temperature mode; a first flow stop determination step in the flow stop determination step is executed, the first flow stop determination step including determining whether the integrated flow control valve is controlled to be in a flow stop state in the room temperature mode; a first flow stop release step in the flow stop release step is executed, the first flow stop release step including releasing flow stop control of the integrated flow control valve in the room temperature mode; performing a first water temperature condition comparison step in the water temperature condition comparison step, the first water temperature condition comparison step including determining whether the temperature of the coolant discharged from the waste heat recovery system is lower than a recovery start temperature that is preset to trigger the waste heat recovery control into the waste heat recovery system, in a case where the temperature of the coolant discharged from the waste heat recovery system is higher than the temperature of the coolant discharged from the engine in the room temperature mode; and performing a first waste heat recovery start step in the waste heat recovery start step, the first waste heat recovery start step including controlling a drive motor provided in the waste heat recovery system to allow the exhaust gas to exchange heat with the coolant in the waste heat recovery system.

19. The method of claim 17, wherein, in the second outside air temperature comparison step, based on the temperature of the outside air not exceeding the low temperature reference temperature: performing a low temperature mode start step in the mode start step, the low temperature mode start step including starting control of the waste heat recovery system and the integrated flow control valve in a low temperature mode; performing a second bypass determination step in the bypass determination step, the second bypass determination step including determining whether the exhaust gas passes through the waste heat recovery system with reduced heat exchange with the coolant or without heat exchange in the low temperature mode; performing a second flow stop determination step in the flow stop determination step, the second flow stop determination step including determining whether the integrated flow control valve is controlled to be in a flow stop state in the low temperature mode; performing a second flow stop release step in the flow stop release step, the second flow stop release step including releasing the flow stop control of the integrated flow control valve in the low temperature mode; performing a second water temperature condition comparison step in the water temperature condition comparison step, the second water temperature condition comparison step including determining whether the temperature of the coolant discharged from the waste heat recovery system is lower than a recovery start temperature that is preset to trigger the waste heat recovery control into the waste heat recovery system, in a case where the temperature of the coolant discharged from the waste heat recovery system is higher than the temperature of the coolant discharged from the engine in the low temperature mode; and performing a second waste heat recovery start step in the waste heat recovery start step, the second waste heat recovery start step including controlling a drive motor provided in the waste heat recovery system to allow the exhaust gas to exchange heat with the coolant in the waste heat recovery system.

Images