Cooling circuit for internal combustion engine

Abstract

To provide a cooling circuit for an internal combustion engine capable of promoting warming-up of the internal combustion engine while suppressing a pump load.SOLUTION: A cooling circuit for an internal combustion engine includes: a first path for circulating cooling water to an internal combustion engine body; a second path connected to a radiator through a path different from the first path to circulate the cooling water to an apparatus different from the internal combustion engine body; a connection path connecting the first path and the second path; a first valve for regulating a flow rate flowing in the connection path; a first pump for circulating the cooling water in the first path; and a second pump for circulating the cooling water in the second path. When a temperature of the cooling water is lower than a first predetermined temperature, the first valve suppresses a flow of the cooling water from the first path to the connection path.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a cooling circuit for an internal combustion engine. [Background technology]

[0002] Conventionally, cooling circuits for internal combustion engines that promote the warming up of the engine have been known (see, for example, Patent Document 1). The cooling circuit for an internal combustion engine in Patent Document 1 promotes the warming up of the engine by utilizing the heat of the exhaust gas emitted from the internal combustion engine. Specifically, the cooling circuit for an internal combustion engine in Patent Document 1 controls a switching valve to allow the coolant to flow around the exhaust pipe while the internal combustion engine is warming up. This transfers the heat of the exhaust gas to the coolant, making it easier for the coolant to warm up. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-87763 Summary of the Invention [Problem to be solved by the invention]

[0004] In the cooling circuit of the internal combustion engine of Patent Document 1, when recovering heat from the exhaust gas, the flow rate of the coolant flowing through the cooling circuit increases, which increases the load on the pump that circulates the coolant.

[0005] An object of the present disclosure is to provide a cooling circuit for an internal combustion engine that can promote warm-up of the internal combustion engine while suppressing the load on the pump. [Means for solving the problem]

[0006] The cooling circuit of an internal combustion engine according to the present disclosure comprises a first path for circulating coolant through an internal combustion engine body, a second path connected to a radiator via a path different from the first path and for circulating coolant to equipment different from the internal combustion engine body, a connecting path connecting the first path and the second path, a first valve for adjusting the flow rate through the connecting path, a first pump for circulating coolant through the first path, and a second pump for circulating coolant through the second path, wherein the first valve suppresses the flow of coolant from the first path to the connecting path when the coolant is below a first predetermined temperature. [Effects of the Invention]

[0007] According to this cooling circuit for an internal combustion engine, the coolant in the first path does not flow into the connecting path when its temperature is below a first predetermined temperature, and therefore does not dissipate heat by passing through the radiator. Therefore, the temperature of the coolant in the first path is likely to rise. As a result, warm-up of the internal combustion engine is promoted. Furthermore, the first path and the second path pass through different routes and become independent paths. The first path and the second path are circulated by separate pumps. When the temperature of the coolant is below the first predetermined temperature, the first pump only needs to circulate the coolant in the first path to a degree that prevents local boiling without considering a temperature rise in the equipment, and therefore the load on the first pump is small. Furthermore, the second pump does not need to circulate the coolant to the internal combustion engine, and only needs to circulate the coolant to a degree that cools the equipment, and therefore the load on the second pump is small. As a result, a cooling circuit for an internal combustion engine can be provided that can promote warm-up of the internal combustion engine while suppressing the load on the pump. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a circuit diagram of a cooling circuit for an internal combustion engine according to an embodiment of the present disclosure; DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0010] 1, the cooling circuit 1 of the internal combustion engine E includes a first path 2, a second path 4, a third path 6, a connection path 8, an air bleeding path 10, a first pump 12, a second pump 14, a first valve 16, a second valve 18, and a control unit 20. The cooling circuit 1 of the internal combustion engine E of this embodiment is mounted on a vehicle.

[0011] The first path 2 circulates the coolant through the internal combustion engine body. In this embodiment, the internal combustion engine body is the cylinder head and cylinder block of the internal combustion engine E (ENG in FIG. 1). The first path 2 flows from the first pump 12 into the cylinder block of the internal combustion engine body, passes from the cylinder block through the cylinder head, returns to the cylinder block again, and is then discharged. The first path 2 returns from the cylinder block to the first pump 12.

[0012] The second path 4 passes through a path different from the first path 2 and is connected to the radiator 22, circulating the coolant to devices other than the internal combustion engine body. Devices through which exhaust gas discharged from the internal combustion engine body flows are arranged on the second path 4. The second path 4 circulates the coolant to these devices. In this embodiment, the devices through which the exhaust gas flows are a turbocharger 24 (T / C in FIG. 1), an exhaust recirculation gas cooler 26 (EGR / C in FIG. 1) that cools the exhaust recirculation gas, an exhaust recirculation gas bypass valve 28 (EGR / BV in FIG. 1) that is arranged on the bypass passage to bypass the exhaust recirculation gas, and an exhaust recirculation gas valve 30 (EGR / V in FIG. 1) that introduces the exhaust recirculation gas into the intake air. The second path 4 exits the second pump 14, passes through the above devices, and is connected to the radiator 22. The second path 4 merges with a first connection path 8a (described later) inside the radiator 22, branches midway, and returns to the second pump 14.

[0013] The third path 6 branches off from the first path 2. The third path 6 merges with the first path 2 downstream of the branch from the first path 2. In this embodiment, the third path 6 branches off from the first path 2 upstream of the internal combustion engine main body. A heating device that uses the heat of the coolant is arranged on the third path 6. In this embodiment, a heater 32 (HEATER in FIG. 1) is arranged on the third path 6. The heater 32 heats the interior of the vehicle using the heat of the coolant. In this embodiment, in addition to the heater 32, an oil cooler 34 (O / C in FIG. 1) that cools oil in the internal combustion engine E or the transmission (not shown) is also arranged on the third path 6. The third path 6 is connected to the first valve 16 downstream of the heater 32 and the oil cooler 34. The third path 6 merges with the first path 2 inside the first valve 16 downstream of the branch from the first path 2 to the third path 6.

[0014] The connection path 8 connects the first path 2 and the second path 4. The connection path 8 has a first connection path 8a and a second connection path 8b. The first connection path 8a branches off from the first path 2 downstream of the internal combustion engine body and is connected to the second path 4 upstream of the radiator 22. In this embodiment, the first connection path 8a is connected to a supply passage in the radiator 22 upstream of a radiator core (not shown) of the radiator 22. The first connection path 8a merges with the second path 4 in the supply passage in the radiator 22. The second connection path 8b extends from downstream of the radiator 22. The second connection path 8b merges with the first path 2 downstream of the branch of the first path 2 and the first connection path 8a. In this embodiment, the second connection path 8b is connected to the first valve 16. The second connection path 8b joins with the first path 2 inside the first valve 16, which is located downstream of the branch point between the first path 2 and the first connection path 8a.

[0015] The air vent path 10 extends from the internal combustion engine body and is connected to a hot bottle 36 (H / B in FIG. 1). The hot bottle 36 functions as a reservoir tank that temporarily stores cooling water and is also a tank for bleeding air from the cooling water. The cooling water flowing through the internal combustion engine body tends to become hot. This makes it easy for air to be generated. For this reason, air is bled from the internal combustion engine body by the air vent path 10. In this embodiment, the second path 4 downstream of the turbocharger 24 is also connected to the hot bottle 36. The cooling water flowing through the turbocharger 24 tends to become hot. By connecting the second path 4 downstream of the turbocharger 24 to the hot bottle 36, air can be bled from the second path 4. The air vent path 10 extends from the hot bottle 36 and is connected to the second connection path 8b.

[0016] The first pump 12 circulates the cooling water in the first path 2. In this embodiment, the first pump 12 is a mechanical pump that rotates an impeller by rotating a rotary shaft 12a.

[0017] The second pump 14 circulates the cooling water in the second path 4. In this embodiment, the second pump 14 is a mechanical pump that rotates an impeller by rotating a rotary shaft 14a.

[0018] The second path 4 has a smaller capacity of coolant than the first path 2. Therefore, the second pump 14 has a smaller discharge amount than the first pump 12. That is, the load on the second pump 14 is smaller than that on the first pump 12.

[0019] In this embodiment, the first pump 12 and the second pump 14 are driven by a single drive source. Specifically, the rotary shaft 14a is rotated by a pulley 40. The pulley 40 is driven by a belt or chain that is wound around the crankshaft of the internal combustion engine E. This structure simplifies the structures of the first pump 12 and the second pump 14.

[0020] A clutch 38 is disposed between the first pump 12 and the second pump 14. Specifically, the clutch 38 is disposed between the rotary shaft 12a of the first pump 12 and the rotary shaft 14a of the second pump 14. A pulley 40, which serves as a drive source, is connected to the rotary shaft 14a on the second pump side. The clutch 38 adjusts the torque transmitted from the pulley 40 by causing the rotary shaft 12a to slip relative to the rotary shaft 14a. In this way, the clutch 38 adjusts the discharge rate of the first pump 12.

[0021] The first valve 16 adjusts the flow rate of the coolant flowing through the connection path 8. Specifically, when the temperature of the coolant reaches or exceeds a first predetermined temperature T1, the first valve 16 opens a valve located between the second connection path 8b and the first path 2 and receives the coolant from the second connection path 8b. This allows the coolant to flow through the first connection path 8a. The first predetermined temperature T1 is, for example, 80°C, which is a target temperature at which the internal combustion engine E is warmed up. When the temperature of the coolant is lower than the first predetermined temperature T1, the first valve 16 blocks the reception of the coolant from the second connection path 8b. This restricts the flow of the coolant into the first connection path 8a, and ultimately prevents the coolant from flowing through the first connection path 8a. In this embodiment, the first valve 16 is an electromagnetic valve controlled by the control unit 20.

[0022] The second valve 18 adjusts the amount of coolant flowing through the third path 6. Specifically, when the temperature reaches a second predetermined temperature T2 that is lower than the first predetermined temperature T1, the second valve 18 opens a valve on the third path 6 to allow the coolant to flow through the third path 6. The second predetermined temperature T2 is a temperature of the coolant that can be used as a heat source for the heater 32, and is, for example, about 50°C. The second predetermined temperature T2 may also be a temperature that can warm the oil in the oil cooler, and may be, for example, a temperature between 40°C and 50°C. In this embodiment, the second valve 18 is an electromagnetic valve controlled by the control unit 20.

[0023] The control unit 20 is electrically connected to the first valve 16, the second valve 18, the clutch 38, and a water temperature sensor 42 that detects the temperature of the coolant, and controls the first valve 16, the second valve 18, and the clutch 38 based on the water temperature detected by the water temperature sensor 42. In this embodiment, the water temperature sensor 42 is disposed downstream of the internal combustion engine body in the first path 2. The control unit 20 is actually an ECU (Electronic Control Unit) configured by a microcomputer including a calculation device, a memory, an input / output buffer, etc. The control unit 20 controls the first valve 16, the second valve 18, and the clutch 38 based on maps and programs stored in the memory. The control unit 20 is also connected to various devices and sensors of the internal combustion engine E, and executes control to maintain the internal combustion engine E in an appropriate operating state.

[0024] In the cooling circuit 1 of the internal combustion engine E configured as above, when the coolant is below the second predetermined temperature T2, the coolant circulates through the first path 2 and the second path 4. Because the temperature is below the second predetermined temperature T2, which is lower than the first predetermined temperature T1, the first valve 16 is closed. Therefore, the coolant does not flow into the connection path 8. As a result, the coolant flows independently through the first path 2 and the second path 4. Because the first path 2 does not pass through the radiator 22 at this time, heat radiation from the coolant in the first path 2 is suppressed. As a result, the temperature of the coolant in the first path 2 is likely to rise. This promotes warming up of the internal combustion engine E.

[0025] The first pump 12 circulates the coolant through the first path 2. The second pump 14 circulates the coolant through the second path 4. The amount of coolant flowing through the components arranged on the second path 4 may be smaller than that through the internal combustion engine itself. Therefore, the volume of coolant flowing through the second path 4 is smaller than that through the first path 2. This allows the second pump 14 to have a smaller discharge volume. Furthermore, when the temperature of the coolant is below the first predetermined temperature T1, the first pump 12 only needs to circulate the coolant through the first path 2, thereby reducing the discharge volume of the first pump 12. This allows the clutch 38 to slip, reducing the torque transmitted to the first pump 12. As a result, the load on the internal combustion engine E is reduced. Furthermore, when the temperature of the coolant is below the first predetermined temperature T1, the first pump 12 only needs to circulate the coolant through the first path 2 to a degree that does not cause local boiling, regardless of the temperature rise of the components, thereby reducing the load on the first pump 12. Furthermore, the load on the second pump 14 is small because it does not need to circulate cooling water to the internal combustion engine E, but only needs to circulate cooling water to the extent that it can cool the equipment. As a result, the load on the first pump 12 and the second pump 14 can be reduced while promoting the warm-up of the internal combustion engine E.

[0026] Furthermore, when the temperature of the cooling water is lower than the second predetermined temperature, the cooling water does not flow through the third path 6, further reducing the load on the first pump 12. In addition, the heater 32 and the oil cooler 34 do not remove heat from the cooling water, which also promotes warming up of the internal combustion engine E.

[0027] Regardless of the temperature of the cooling water, the cooling water always flows through the second path 4. This allows the devices whose temperature is likely to rise due to the exhaust gas from the internal combustion engine E to be constantly cooled.

[0028] When the temperature of the coolant reaches or exceeds the second predetermined temperature T2, the second valve 18 opens. This allows the coolant to flow through the third path 6. When the coolant flows through the third path 6, the interior of the vehicle can be heated. Furthermore, when the coolant flows through the third path 6, the oil is heated, which reduces the viscosity of the oil and reduces friction in the internal combustion engine E or the transmission.

[0029] When the temperature of the coolant reaches or exceeds the first predetermined temperature T1, the first valve 16 opens, causing the coolant to flow through the connecting path 8, and the coolant in the first path 2 passes through the radiator 22 and returns to the first path 2. This allows the internal combustion engine E to be cooled after warming up.

[0030] As described above, according to the present disclosure, it is possible to provide the cooling circuit 1 for the internal combustion engine E that can promote the warm-up of the internal combustion engine E while suppressing the load on the pump.

[0031] <Other embodiments> Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible within the scope of the gist of the invention. In particular, the multiple modifications described in this specification can be arbitrarily combined as necessary.

[0032] (a) In the above embodiment, the first valve 16 is described as an electromagnetic valve, but the present disclosure is not limited to this. The first valve 16 may be a thermostat valve that opens when the coolant temperature reaches or exceeds the first predetermined temperature T1.

[0033] (b) In the above embodiment, the second valve 18 is described as an electromagnetic valve, but the present disclosure is not limited to this. The second valve 18 may be a thermostat valve that opens when the coolant temperature reaches or exceeds the second predetermined temperature T2.

[0034] (c) In the above embodiment, the first pump 12 and the second pump 14 are mechanical pumps driven by the pulley 40, but the present disclosure is not limited to this. The first pump 12 and the second pump 14 may be electric water pumps driven by independent motors. Furthermore, the first pump 12 and the second pump 14 may be electric water pumps in which the rotary shafts 12a and 14a are rotated by motors instead of the pulley 40. [Explanation of symbols]

[0035] E: Internal combustion engine, 1: Cooling circuit 2: Route 1, 4: Route 2, 6: Route 3 8: Connection path, 8a: First connection path, 8b: Second connection path 12: First pump, 14: Second pump 16: 1st valve, 18: 2nd valve 22: Radiator, 32: Heater, 38: Clutch T1: 1st predetermined temperature, T2: 2nd predetermined temperature

Claims

1. a first path for circulating cooling water through the internal combustion engine body; a second path that passes through a path different from the first path and is connected to a radiator, and circulates the cooling water to a device different from the internal combustion engine body; a connection path connecting the first path and the second path; a first valve for adjusting the flow rate of the fluid flowing through the connection path; a first pump that circulates the cooling water through the first path; a second pump that circulates the cooling water through the second path; Equipped with the first valve restricts the flow of the cooling water from the first path to the connecting path when the cooling water is at a temperature lower than a first predetermined temperature; Cooling circuit of an internal combustion engine.

2. The connection path is a first connection path that branches off from the first path downstream of the internal combustion engine body and is connected to the second path upstream of the radiator; a second connection path extending from the second path downstream of the radiator and merging with the first path downstream of a branch point between the first path and the first connection path; having 2. The cooling circuit of claim 1.

3. a third path branching from the first path and joining the first path downstream of the branch; a second valve that adjusts the amount of cooling water flowing through the third path; Furthermore, a heater is disposed on the third path; the second valve allows the cooling water to flow through the third path when the temperature reaches or exceeds a second predetermined temperature that is lower than the first predetermined temperature; 2. A cooling circuit for an internal combustion engine according to claim 1.

4. A device through which exhaust gas discharged from the internal combustion engine flows is disposed in the second path.

2. The cooling circuit of claim 1.

5. The second path has a smaller capacity of the cooling water than the first path, The second pump has a smaller discharge volume than the first pump.

2. The cooling circuit of claim 1.

6. the first pump and the second pump are driven by a single driving source; 6. A cooling circuit for an internal combustion engine according to any one of claims 1 to 5.

7. a clutch is disposed between the first pump and the second pump, the drive source is connected to the second pump side, and the clutch adjusts the discharge amount of the first pump; 7. A cooling circuit for an internal combustion engine according to claim 6.

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