Cooling system for internal combustion engines

Abstract

The objective is to provide a cooling device for an internal combustion engine that can suppress the freezing of the throttle valve. [Solution] A cooling system for an internal combustion engine comprising: a first cooling water passage connected to an internal combustion engine; a second cooling water passage connected to a throttle valve; a third cooling water passage connected to the first cooling water passage; a first pump; a second pump provided upstream of the first pump and upstream of the position in the first cooling water passage to which the third cooling water passage is connected; and a control unit that controls the first pump and the second pump, wherein the control unit switches between a first control using the first pump to circulate cooling water in the order of the first cooling water passage, the internal combustion engine, the second cooling water passage, the throttle valve, and the third cooling water passage, and a second control using the second pump to circulate cooling water in the order of the first cooling water passage, the third cooling water passage, and the throttle valve.

Description

Technical Field

[0001] The present invention relates to a cooling device for an internal combustion engine.

Background Art

[0002] Techniques have been developed to prevent the throttle valve from freezing by circulating the cooling water of an internal combustion engine through the throttle valve (for example, Patent Document 1, etc.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, for example, in a low-temperature environment, etc., the throttle valve cannot be sufficiently heated, and there is a risk of freezing. Therefore, an object is to provide a cooling device for an internal combustion engine capable of suppressing the freezing of the throttle valve.

Means for Solving the Problems

[0005] The above objective can be achieved by a cooling system for an internal combustion engine comprising: a first cooling water passage connected to an internal combustion engine; a second cooling water passage connected to the internal combustion engine and a throttle valve; a third cooling water passage connected to the throttle valve and the first cooling water passage; a first pump provided in the first cooling water passage; a second pump provided in the first cooling water passage upstream of the first pump and upstream of the position to which the third cooling water passage is connected; and a control unit that controls the first pump and the second pump, wherein the control unit switches between a first control using the first pump to circulate cooling water in the order of the first cooling water passage, the internal combustion engine, the second cooling water passage, the throttle valve, and the third cooling water passage; and a second control using the second pump to circulate cooling water in the order of the first cooling water passage, the third cooling water passage, and the throttle valve.

[0006] If the temperature of the cooling water is above a predetermined temperature, the control unit may perform the first control; if the temperature of the cooling water is below the predetermined temperature, the control unit may perform the second control.

[0007] A turbocharger is provided upstream of the second pump in the first cooling water passage, an inlet is provided between the first pump and the second pump in the first cooling water passage, the third cooling water passage is connected to the inlet and the throttle valve, in the first control, the cooling water may flow from the throttle valve to the inlet through the third cooling water passage, and in the second control, the cooling water may flow from the inlet to the throttle valve through the third cooling water passage.

[0008] The system comprises the internal combustion engine, the throttle valve, and a fourth coolant passage connected to the first coolant passage, wherein a heat exchanger for heat exchange of the coolant is provided in the fourth coolant passage, and in the first control, the coolant may circulate from the internal combustion engine through the fourth coolant passage to the first coolant passage, and in the second control, the coolant may circulate from the throttle valve through the fourth coolant passage to the first coolant passage.

[0009] The control unit may, in the first control, operate the first pump without operating the second pump, and in the second control, operate the second pump without operating the first pump. [Effects of the Invention]

[0010] This invention provides a cooling system for an internal combustion engine that can suppress the freezing of the throttle valve. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic diagram illustrating a cooling device according to an embodiment. [Figure 2] Figure 2 is a schematic diagram illustrating a cooling device according to an embodiment. [Figure 3] Figure 3 is a flowchart illustrating the process in the embodiment. [Modes for carrying out the invention]

[0012] The cooling system 100 for the internal combustion engine of this embodiment will be described below with reference to the drawings. Figures 1 and 2 are schematic diagrams illustrating the cooling system 100 according to the embodiment. Figure 1 represents the first control described later. Figure 2 represents the second control described later. The arrows in the figures indicate the direction of the flow of the cooling water. The cooling system 100 performs either the first control or the second control to circulate the cooling water.

[0013] The internal combustion engine 10 has a cylinder head 12 and a cylinder block 14. Water jackets are provided on the cylinder head 12 and the cylinder block 14. Cooling water flows through the water jackets, thereby cooling the internal combustion engine 10.

[0014] The cooling system 100 includes a pump 30 (first pump), a pump 32 (second pump), a cooling water passage 40 (first cooling water passage), a cooling water passage 50 (second cooling water passage), a cooling water passage 52 (third cooling water passage), a cooling water passage 48 (fourth cooling water passage), and an ECU (Electronic Control Unit) 60.

[0015] The cooling water passage 40 includes cooling water passages 41, 42, 43, and 44, and the inlet 21. Cooling water passage 41 is connected to the cylinder head 12 and the turbocharger 20. Cooling water passage 42 is connected to the turbocharger 20 and the pump 32. Cooling water passage 43 is connected to the pump 32 and the inlet 21. Cooling water passage 44 is connected to the inlet 21 and the pump 30. The pump 30 is located near the cylinder block 14 and is situated downstream of the pump 32 and the inlet 21 in the cooling water passage 40. The pump 32 is located downstream of the turbocharger 20 and upstream of the pump 30 and the inlet 21. Pumps 30 and 32 are electric pumps.

[0016] Outlet 23 is connected to the cylinder block 14. Cooling water passage 45 is connected to the cylinder head 12 and outlet 23. Cooling water passage 46 is connected to the cylinder block 14 and oil cooler (O / C) 18. Cooling water passage 47 is connected to the O / C 18 and outlet 23.

[0017] A thermostat 22 is provided in the inlet 21. The thermostat 22 is a valve device that operates according to the temperature of the coolant, for example, and changes its opening degree according to the water temperature. The coolant passage 48 is connected between the outlet 23 and the thermostat 22. A radiator 24 is provided in the middle of the coolant passage 48.

[0018] The throttle valve 26 is provided in an intake pipe (not shown) and adjusts the flow rate of air in the intake pipe. A cooling water passage 50 is connected between the throttle valve 26 and the outlet 23. A cooling water passage 52 is connected between the throttle valve 26 and the inlet 21.

[0019] The ECU 60 is a control device and includes an arithmetic unit such as a CPU (Central Processing Unit) and storage devices such as a RAM (Random Access Memory) and a ROM (Read Only Memory). The ECU 60 performs various controls by executing programs stored in the ROM or the storage device.

[0020] The ECU 60 is connected to the temperature sensor 54, the pumps 30 and 32. The temperature sensor 54 detects, for example, the temperature of the cooling water. The ECU 60 acquires the temperature from the temperature sensor 54. The ECU 60 controls the on / off of the pumps 30 and 32 and also controls the rotational speed of the pumps.

[0021] FIG. 3 is a flowchart illustrating the processing in the embodiment. The ECU 60 acquires the water temperature T from the temperature sensor 54. The ECU 60 determines whether or not the water temperature T is equal to or higher than a predetermined temperature Tth (step S10). In the case of an affirmative determination (Yes), the ECU 60 performs the first control (step S12). In the case of a negative determination (No), the ECU 60 performs the second control (step S14). After step S12 or S14, the processing ends.

[0022] FIG. 1 represents the first control. In the first control, the pump 30 is driven and the pump 32 is not driven. By driving the pump 30, the cooling water circulates through the cooling water passage 40 and flows into the internal combustion engine 10. The cooling water flows through the water jacket of the cylinder head 12 and the water jacket of the cylinder block 14 to cool the internal combustion engine 10.

[0023] A part of the cooling water flows from the cylinder head 12 to the turbocharger 20 through the cooling water passage 41, and then flows to the inlet 21 through the cooling water passages 42 and 43. The cooling water flows through the cooling water passage 44 and is supplied from the inlet 21 to the cylinder block 14.

[0024] A part of the cooling water flows through the cooling water passage 45 and is supplied from the cylinder head 12 to the outlet 23. Another part of the cooling water is supplied from the cylinder head 12 to the O / C 18, where heat exchange is performed with the oil. The cooling water after heat exchange flows through the cooling water passage 47 and is supplied to the outlet 23. A part of the cooling water flows from the outlet 23 into the cooling water passage 48, where heat exchange is performed in the radiator 24, and then is supplied to the inlet 21 through the thermostat 22.

[0025] Another part of the cooling water flows through the cooling water passage 50 and is supplied from the outlet 23 to the throttle valve 26 to cool the throttle valve 26. The cooling water is supplied from the throttle valve 26 to the inlet 21 through the cooling water passage 52. The cooling water circulates back to the internal combustion engine 10 from the inlet 21.

[0026] Figure 2 represents the second control. The description of the same content as the first control is omitted. In the second control, the pump 32 is driven and the pump 30 is not driven. When the pump 32 rotates, the cooling water flows through the cooling water passage 43 and is supplied to the inlet 21. The cooling water flows from the inlet 21 to the throttle valve 26 through the cooling water passage 52. The cooling water circulates from the throttle valve 26 to the cooling water passage 48 through the cooling water passage 50 and the outlet 23.

[0027] The driving pump 32 generates heat, and the temperature of the cooling water rises in the pump 32. When the cooling water with the increased temperature is supplied to the throttle valve 26, the throttle valve 26 is heated. The freezing of the throttle valve 26 is suppressed.

[0028] According to the embodiment, the ECU 60 switches between the first control and the second control (steps S10 and S12). In the first control, the pump 30 is driven and coolant flows from the coolant passage 40 to the internal combustion engine 10. Coolant flows from the internal combustion engine 10 to the throttle valve 26 through the coolant passage 50.

[0029] In the second control, the pump 32 is driven and supplies coolant from the coolant passage 40 to the throttle valve 26 through the coolant passage 52. In other words, the throttle valve 26 is located upstream of the internal combustion engine 10, allowing coolant to flow to the throttle valve 26 without going through the internal combustion engine 10. By quickly supplying the coolant heated by the pump 32 to the throttle valve 26, freezing of the throttle valve 26 can be suppressed.

[0030] If the water temperature T is above a predetermined temperature Tth, the ECU 60 performs a first control. By circulating coolant through the operating internal combustion engine 10, the internal combustion engine 10 can be effectively cooled. If the water temperature T is below the predetermined temperature Tth, the ECU 60 performs a second control. For example, when the internal combustion engine 10 is stopped, the temperature of the coolant tends to drop. In the second control, the low-temperature coolant is heated by the pump 32. The heated coolant flows into the throttle valve 26, effectively suppressing freezing of the throttle valve 26. The ECU 60 may switch between the first and second controls based on the ambient temperature.

[0031] In the second control system, the pump 30 is not driven, making it difficult for coolant to flow from the inlet 21 towards the internal combustion engine 10. Coolant is then introduced from the pump 32 to the throttle valve 26 without passing through the internal combustion engine 10. By introducing coolant to the throttle valve 26 via the shortest possible route, freezing can be effectively suppressed.

[0032] As shown in Figures 1 and 2, the cooling water passage 40 is equipped with a turbocharger 20, a pump 32, an inlet 21, and another pump 30 in order from upstream to downstream. In the first control, the pump 30 is driven to circulate cooling water from the inlet 21 to the internal combustion engine 10, thereby cooling the engine. In the second control, the pump 32 is driven to circulate cooling water in the order of pump 32, inlet 21, and throttle valve 26, thereby heating the throttle valve 26. Only the arrangement of parts needs to be changed, and no additional parts need to be added. This helps to suppress cost increases. In the second control, cooling water may also be introduced from the inlet 21 to the throttle valve 26 and other parts such as a PCV valve (not shown), without going through the internal combustion engine 10. This helps to suppress freezing of the parts.

[0033] The coolant flows through the coolant passage 48 and circulates to the inlet 21 of the coolant passage 40. The coolant used for cooling the internal combustion engine 10, heating the throttle valve 26, etc., undergoes heat exchange in the radiator 24 and then circulates. The coolant can be reused repeatedly.

[0034] Although preferred embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the invention as described in the claims. [Explanation of Symbols]

[0035] 10 Internal combustion engine, 12 Cylinder head, 14 Cylinder block, 18 Oil cooler, 20 Turbocharger, 21 Inlet, 22 Thermostat, 23 Outlet, 24 Radiator, 26 Throttle valve, 30, 32 Pump, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 52 Coolant passage, 54 Temperature sensor, 60 ECU, 100 Cooling system

Claims

1. A first cooling water passage connected to an internal combustion engine, A second cooling water passage connected to the internal combustion engine and the throttle valve, A third cooling water passage connected to the throttle valve and the first cooling water passage, A first pump provided in the first cooling water passage, A second pump is provided in the first cooling water passage upstream of the first pump, and upstream of the position in the first cooling water passage to which the third cooling water passage is connected, The system comprises a control unit that controls the first pump and the second pump, The control unit, A first control system is provided that uses the first pump to circulate the coolant in the following order: the first coolant passage, the internal combustion engine, the second coolant passage, the throttle valve, and the third coolant passage. A cooling system for an internal combustion engine that switches between a second control, which uses the second pump to circulate coolant in the order of the first coolant passage, the third coolant passage, and the throttle valve.

2. If the temperature of the cooling water is above a predetermined temperature, the control unit performs the first control. The cooling device for an internal combustion engine according to claim 1, wherein the control unit performs the second control when the temperature of the cooling water is below the predetermined temperature.

3. A turbocharger is provided in the first cooling water passage upstream of the second pump. An inlet is provided between the first pump and the second pump in the first cooling water passage. The third cooling water passage is connected to the inlet and the throttle valve, In the first control described above, the cooling water flows from the throttle valve to the inlet through the third cooling water passage. In the second control, the cooling water flows from the inlet to the throttle valve through the third cooling water passage, as described in claim 1 or 2.

4. The system comprises the internal combustion engine, the throttle valve, and a fourth cooling water passage connected to the first cooling water passage. A heat exchanger for heat exchange of the cooling water is provided in the fourth cooling water passage. In the first control, the cooling water is circulated from the internal combustion engine through the fourth cooling water passage to the first cooling water passage. The cooling device for an internal combustion engine according to claim 1 or 2, wherein in the second control, the cooling water is circulated from the throttle valve through the fourth cooling water passage to the first cooling water passage.

5. The cooling device for an internal combustion engine according to claim 1 or 2, wherein the control unit operates the first pump and does not operate the second pump in the first control, and operates the second pump and does not operate the first pump in the second control.

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