Cooling device for internal combustion engine

Abstract

The present invention addresses the problem of providing a cooling device for an internal combustion engine capable of suppressing freezing of a throttle valve. The cooling device includes: a first cooling water passage connected to the internal combustion engine; a second cooling water passage connected to the internal combustion engine and the throttle valve; a third cooling water channel connected with the throttle valve and the first cooling water channel; a first pump provided in the first cooling water passage; a second pump provided upstream of the first cooling water passage than the first pump and upstream of a position where the third cooling water passage is connected to the first cooling water passage; and a control unit for controlling the first pump and the second pump, the control unit performing: a first control for circulating 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 using the first pump; and a second control for circulating the cooling water in the order of the first cooling water passage, the third cooling water passage, and the throttle valve using the second pump.

Description

Technical Field

[0001] This invention relates to a cooling device for an internal combustion engine. Background Technology

[0002] A technique has been developed to eliminate icing in the throttle valve by circulating the cooling water of the internal combustion engine within the throttle valve (e.g., Patent Document 1, etc.).

[0003] Patent document 1: Japanese Patent Application Publication No. 2013-024110. Summary of the Invention

[0004] However, in environments such as low temperatures, the throttle valve may not be heated sufficiently and could potentially freeze. Therefore, the object of the present invention is to provide a cooling device for an internal combustion engine that can suppress icing of the throttle valve.

[0005] The above objective can be achieved by a cooling device for an internal combustion engine comprising: a first cooling water passage connected to the 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 disposed in the first cooling water passage; a second pump disposed in the first cooling water passage at a position upstream of the first pump and upstream of the position in the first cooling water passage connected to the third cooling water passage; and a control unit that controls the first pump and the second pump, the control unit switching as follows: a first control that uses the first pump to allow cooling water to flow 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 that uses the second pump to allow cooling water to flow in the order of the first cooling water passage, the third cooling water passage, and the throttle valve.

[0006] When the temperature of the cooling water is above the specified temperature, the control unit performs the first control; when the temperature of the cooling water is below the specified temperature, the control unit can perform the second control.

[0007] A turbocharger is installed upstream of the second pump in the first cooling water channel. An air inlet is provided between the first pump and the second pump in the first cooling water channel. The third cooling water channel is connected to the air inlet and the throttle valve. In the first control, the cooling water flows from the throttle valve to the air inlet through the third cooling water channel. In the second control, the cooling water can flow from the air inlet to the throttle valve through the third cooling water channel.

[0008] The device includes 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 circulates from the internal combustion engine through the fourth cooling water passage to the first cooling water passage. In the second control, the cooling water can circulate from the throttle valve through the fourth cooling water passage to the first cooling water passage.

[0009] The control unit activates the first pump but not the second pump in the first control, and activates the second pump but not the first pump in the second control. Invention Effects

[0010] A cooling device for an internal combustion engine that can suppress icing of the throttle valve can be provided. Attached Figure Description

[0011] Figure 1 This is a schematic diagram illustrating the cooling device involved in the illustrative embodiment. Figure 2 This is a schematic diagram illustrating the cooling device involved in the illustrative embodiment. Figure 3 This is a flowchart illustrating the process in an illustrative implementation. Detailed Implementation

[0012] Hereinafter, the cooling device 100 of the internal combustion engine of this embodiment will be described with reference to the accompanying drawings. Figure 1 and Figure 2 This is a schematic diagram illustrating the cooling device 100 according to an exemplary embodiment. Figure 1 This indicates the first control, which will be discussed later. Figure 2 This indicates the second control described later. The arrows in the diagram indicate the direction of cooling water flow. The cooling device 100 performs either the first or 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 to cool the internal combustion engine 10.

[0014] The cooling device 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 electronic control unit (ECU) 60.

[0015] The cooling water passage 40 includes cooling water passages 41, 42, 43, and 44, and an air intake 21. Cooling water passage 41 connects to the cylinder head 12 and the turbocharger 20. Cooling water passage 42 connects to the turbocharger 20 and the pump 32. Cooling water passage 43 connects to the pump 32 and the air intake 21. Cooling water passage 44 connects to the air intake 21 and the pump 30. The pump 30 is located near the cylinder block 14, downstream of the pump 32 and the air intake 21 within the cooling water passage 40. The pump 32 is located downstream of the turbocharger 20 and upstream of the pump 30 and the air intake 21. Both pumps 30 and 32 are electric pumps.

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

[0017] A thermostat 22 is installed at the air inlet 21. The thermostat 22 is, for example, a valve device that operates according to the temperature of the cooling water, changing its opening degree according to the water temperature. A cooling water passage 48 connects the air outlet 23 and the thermostat 22. A radiator 24 is installed in the middle of the cooling water passage 48.

[0018] A throttle valve 26 is installed in the intake pipe (not shown) and regulates the airflow within 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 intake port 21.

[0019] The ECU60 is a control device equipped with a central processing unit (CPU) and other computing devices, as well as random access memory (RAM) and read-only memory (ROM). The ECU60 performs various controls by executing programs stored in the ROM or other storage devices.

[0020] ECU 60 is connected to temperature sensor 54, pumps 30 and 32. Temperature sensor 54 detects, for example, the temperature of coolant. ECU 60 obtains the temperature from temperature sensor 54. ECU 60 controls the on / off state of pumps 30 and 32, and also controls the pump speed.

[0021] Figure 3This is a flowchart illustrating the process in an illustrative embodiment. ECU 60 acquires the water temperature T from the temperature sensor 54. ECU 60 determines whether the water temperature T is above a predetermined temperature Tth (step S10). If the determination is affirmative (Yes), ECU 60 performs the first control (step S12). If the determination is negative (No), ECU 60 performs the second control (step S14). After step S12 or S14, the process ends.

[0022] Figure 1 This indicates the first control. In the first control, pump 30 is driven, while pump 32 is not driven. Driven by pump 30, cooling water circulates in the cooling water passage 40 and flows into the internal combustion engine 10. The cooling water flows through the water jacket of cylinder head 12 and the water jacket of cylinder block 14, thereby cooling the internal combustion engine 10.

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

[0024] A portion of the coolant flows through coolant passage 45 and is supplied from cylinder head 12 to outlet 23. Another portion of the coolant is supplied from cylinder head 12 to O / C 18, where it undergoes heat exchange with oil. The cooled water, after heat exchange, flows through coolant passage 47 and is supplied to outlet 23. A portion of the coolant flows from outlet 23 to coolant passage 48, undergoes heat exchange in radiator 24, and is supplied to intake 21 via thermostat 22.

[0025] Another portion of the cooling water flows through cooling water passage 50 and is supplied from outlet 23 to throttle valve 26, thereby cooling throttle valve 26. Cooling water from throttle valve 26 is supplied from cooling water passage 52 to intake port 21. Cooling water is then recirculated from intake port 21 back to internal combustion engine 10.

[0026] Figure 2 This indicates the second control. Descriptions identical to those in the first control are omitted. In the second control, pump 32 is driven, while pump 30 is not driven. Due to the rotation of pump 32, cooling water is supplied to the air inlet 21 via cooling water passage 43. Cooling water flows from the air inlet 21 to the throttle valve 26 via cooling water passage 52. Cooling water circulates from the throttle valve 26 back to the cooling water passage 48 via cooling water passage 50 and air outlet 23.

[0027] The pump 32, which is in operation, generates heat, causing the temperature of the cooling water in the pump 32 to rise. This heated cooling water is then supplied to the throttle valve 26, which is then heated to prevent icing.

[0028] According to the implementation method, ECU60 switches between first control and second control (steps S10 and S12). In the first control, pump 30 is driven, and cooling water flows from cooling water passage 40 to internal combustion engine 10. Cooling water flows from internal combustion engine 10 through cooling water passage 50 to throttle valve 26.

[0029] In the second control, the pump 32 is driven, and cooling water is supplied from the cooling water passage 40 through the cooling water passage 52. In other words, the throttle valve 26 is located upstream of the internal combustion engine 10, allowing cooling water to flow to the throttle valve 26 without passing through the internal combustion engine 10. By rapidly channeling the cooling water heated by the pump 32 to the throttle valve 26, icing of the throttle valve 26 can be prevented.

[0030] When the coolant temperature T is above the specified temperature Tth, ECU 60 performs the first control. By circulating coolant in the operating internal combustion engine 10, the internal combustion engine 10 can be effectively cooled. When the coolant temperature T is below the specified temperature Tth, ECU 60 performs the second control. For example, when the internal combustion engine 10 is stopped, the coolant temperature tends to drop. In the second control, the low-temperature coolant is heated by pump 32. By allowing the heated coolant to flow into the throttle valve 26, icing of the throttle valve 26 can be effectively suppressed. ECU 60 can switch between the first and second controls based on the external temperature.

[0031] In the second control, since pump 30 is not driven, cooling water does not easily flow from intake port 21 towards internal combustion engine 10. Instead of passing through internal combustion engine 10, cooling water flows from pump 32 into throttle valve 26. By allowing cooling water to flow into throttle valve 26 with the shortest possible distance, icing can be effectively suppressed.

[0032] like Figure 1 and Figure 2 As shown, in the cooling water passage 40, a turbocharger 20, a pump 32, an air intake 21, and another pump 30 are arranged sequentially from upstream to downstream. In the first control, the pump 30 is driven to circulate cooling water from the air intake 21 to the internal combustion engine 10, thereby cooling the internal combustion engine 10. In the second control, the pump 32 is driven to circulate cooling water in the order of pump 32, air intake 21, and throttle valve 26, thereby heating the throttle valve 26. Only the configuration of the components needs to be changed; no additional components are required. This helps to suppress cost increases. In the second control, cooling water can also flow from the air intake 21 to the throttle valve 26 and components such as the PCV valve (not shown) without passing through the internal combustion engine 10. This helps to prevent icing of components.

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

[0034] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to this specific embodiment. Various modifications and alterations can be made within the scope of the spirit of the present invention as set forth in the claims. Symbol Explanation

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

Claims

1. A cooling device for an internal combustion engine, characterized in that, have: The first cooling water passage is connected to the internal combustion engine; The second cooling water passage is connected to the internal combustion engine and the throttle valve; The third cooling water passage is connected to the throttle valve and the first cooling water passage; The first pump is located in the first cooling water channel; The second pump is located in the first cooling water channel at a position further upstream than the first pump and further upstream than the position in the first cooling water channel connected to the third cooling water channel; and The control unit controls the first pump and the second pump. The control unit performs the following switching: The first control, using the first pump, causes cooling water to flow 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 The second control uses the second pump to allow cooling water to flow in the order of the first cooling water passage, the third cooling water passage, and the throttle valve.

2. The cooling device for an internal combustion engine according to claim 1, characterized in that, When the temperature of the cooling water is above a specified temperature, the control unit performs the first control. If the temperature of the cooling water is lower than the specified temperature, the control unit performs the second control.

3. The cooling device for an internal combustion engine according to claim 1 or 2, characterized in that, A turbocharger is installed in the first cooling water channel, further upstream than the second pump. An air inlet is provided between the first pump and the second pump in the first cooling water channel. The third cooling water channel is connected to the air inlet and the throttle valve. In the first control, the cooling water flows from the throttle valve to the air inlet through the third cooling water channel. In the second control, the cooling water flows from the air inlet to the throttle valve through the third cooling water channel.

4. The cooling device for an internal combustion engine according to claim 1 or 2, characterized in that, It includes 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 channel. In the first control, the cooling water circulates from the internal combustion engine to the first cooling water passage through the fourth cooling water passage. In the second control, the cooling water circulates from the throttle valve through the fourth cooling water channel to the first cooling water channel.

5. The cooling device for an internal combustion engine according to claim 1 or 2, characterized in that, The control unit activates the first pump but not the second pump in the first control, and activates the second pump but not the first pump in the second control.

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