JP2012184754A - Cooling system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote warm-up, prevent a throttle body from freezing, and suppress slapping sound of a piston.SOLUTION: A cooling system 100 includes: a first circulation path in which a coolant discharged from a water pump 1 returns to the water pump 1 by way of an engine 2, an electric valve 3, a heater core 41, and an EGR cooler 42 (waste heat recovery device 43), and a thermostat 11 in sequence; and a second circulation path in which the coolant discharged from the water pump 1 returns to the water pump 1 by way of the engine 2, the throttle body 51, an EGR valve 52, and the thermostat 11 in sequence. In an engine block 2A (refer to Fig.2), the second circulation path is formed so as to communicate with an upper part of the engine block.

Description

  The present invention relates to a cooling device that limits the circulation of cooling water to an engine when the engine is in a warm-up operation state.

  Conventionally, in order to reduce the friction loss when starting the engine at a low temperature and improve the fuel efficiency of the engine, the engine warm-up period is shortened (hereinafter also referred to as “promoting warm-up”). The technology has been proposed.

  For example, a cooling water flow rate control device for an internal combustion engine that controls the flow rate of cooling water in a bypass passage that passes through a throttle body via a water jacket of the engine to a fully closed flow rate or a minute flow rate in a warm-up operation state is disclosed. (See Patent Document 1). According to this cooling water flow rate control device, warming up can be promoted as the flow rate of the cooling water in the bypass passage is reduced.

JP 2002-21563 A

  However, in the cooling water flow control device for an internal combustion engine described in Patent Document 1, the flow rate of the cooling water in the bypass passage passing through the throttle body via the water jacket of the engine is very small in order to promote warm-up. When the flow rate is controlled, the cooling of the upper part of the cylinder bore of the engine may be insufficient and the flow rate of the cooling water flowing through the throttle body may be insufficient.

  That is, since the flow rate of the cooling water flowing through the upper part of the engine cylinder bore is small, the upper part of the engine cylinder bore may locally become hot. Further, the upper part of the cylinder bore of the engine becomes high temperature and deforms due to thermal expansion, and there is a risk that the piston hitting sound will increase. Further, since the flow rate of the cooling water flowing through the throttle body is small, there is a possibility that the throttle body will freeze.

  The present invention has been made in view of the above problems, and aims to provide a cooling device capable of promoting warm-up, preventing freezing of the throttle body, and suppressing piston hitting sound. Yes.

  In order to solve the above problems, the cooling device according to the present invention is configured as follows.

  That is, the cooling device according to the present invention is a cooling device that restricts the flow rate of the cooling water that circulates through the engine when the engine is in a warm-up operation state, and passes through the radiator through the engine. The first circulation path is configured to be able to circulate the cooling water without using the cooling water, the shut-off valve is provided in the first circulation path and conducts or blocks the cooling water, and the cooling water is passed through the engine and the throttle body. The second circulation path is configured to be circulated and is different from the first circulation path, and the second circulation path is formed in communication with the upper part of the engine block.

  According to the cooling device having such a configuration, the cooling water that circulates through the first circulation path that is the circulation path of the cooling water that passes through the engine and does not pass through the radiator is blocked by setting the shut-off valve to the shut-off state. Since the cooling water circulating through the second circulation path, which is the cooling water circulation path passing through the engine and the throttle body, can be conducted, warm-up can be promoted and the throttle body can be prevented from freezing. Further, since the second circulation path is formed in the engine block so as to communicate with the upper part thereof, it is possible to suppress piston hitting sound.

  That is, the piston hitting sound is generated when the upper part of the cylinder bore becomes hot and deforms due to thermal expansion, and the upper part of the cylinder bore is caused by the cooling water flowing through the second circulation path formed in communication with the upper part of the engine block. Since it is cooled, piston hitting sound can be suppressed.

  In the cooling device according to the present invention, it is preferable that the second circulation path is formed to communicate with the vicinity of the cylinder head.

  According to the cooling device having such a configuration, the upper part of the cylinder bore is further efficiently cooled by the cooling water flowing through the second circulation path formed in communication with the vicinity of the cylinder head in the upper part of the engine block. Sound can be further suppressed.

  That is, since the upper part of the cylinder bore is close to the vicinity of the cylinder head in the upper part of the engine block where the second circulation path is formed, the upper part of the cylinder bore can be cooled more efficiently.

  In the cooling device according to the present invention, it is preferable that the cooling water outlet of the second circulation path in the engine block is formed on the side away from the cooling water inlet to the engine block.

  According to the cooling device having such a configuration, the cooling water outlet of the second circulation path in the engine block is formed on the side away from the cooling water inlet to the engine block. Furthermore, it can cool efficiently.

  That is, for example, the engine includes four cylinders, the first cylinder to the fourth cylinder are arranged in a straight line in order, and the coolant inlet to the engine block is arranged in the vicinity of the first cylinder. If the cooling water outlet of the second circulation path is formed on the side away from the inlet (here, in the vicinity of the fourth cylinder), the cooling water flowing in from the inlet is Since the gas flows out from the outlet through the first cylinder to the fourth cylinder in order, the upper part of the cylinder bore can be cooled more efficiently.

  In the cooling device according to the present invention, when the water pump for circulating the cooling water is driven in the second circulation path, the flow rate of the cooling water circulating through the second circulation path is set to a preset flow rate. It is preferably configured to be equal to or less than the threshold value.

  According to the cooling device having such a configuration, when the water pump that circulates the cooling water is driven, the flow rate of the cooling water that circulates through the second circulation path is equal to or less than a preset flow rate threshold value. By setting the threshold value to an appropriate value, warm-up can be promoted.

  In the cooling device according to the present invention, it is preferable that the second circulation path has a diameter of a pipe constituting the second circulation path set to be equal to or smaller than a preset diameter threshold value.

  According to the cooling device having such a configuration, since the diameter of the pipe constituting the second circulation path is set to be equal to or smaller than a preset diameter threshold, the diameter threshold is set to an appropriate value, thereby simplifying. Warm-up can be promoted by the configuration.

  That is, for example, when controlling the flow rate of the water pump that circulates the cooling water so that the flow rate of the cooling water that circulates in the second circulation path is less than or equal to a preset flow rate threshold value, the water pump is a variable flow rate pump. It is necessary to. On the other hand, the flow rate of the cooling water circulating through the second circulation path is set by setting the diameter of the pipe constituting the second circulation path to be equal to or smaller than a preset diameter threshold value and setting the diameter threshold value to an appropriate value. When the flow rate is set to be equal to or lower than a preset flow rate threshold value, the water pump does not need to be a variable flow rate pump, so warm-up can be promoted with a simple configuration.

  In the cooling device according to the present invention, it is preferable that the second circulation path is further configured to be able to circulate cooling water via an EGR valve.

  According to the cooling device having such a configuration, the second circulation path is further configured to be able to circulate cooling water via the EGR valve, so that the EGR valve can be prevented from freezing.

  In the cooling device according to the present invention, it is preferable that the second circulation path is configured to be able to circulate cooling water via an exhaust heat recovery device.

  According to the cooling device having such a configuration, since the second circulation path is configured to be able to circulate the cooling water via the exhaust heat recovery device, the boiling of the cooling water in the exhaust heat recovery device can be avoided. Can do.

  The cooling device according to the present invention further comprises an opening / closing instruction means for instructing opening / closing of the shut-off valve, and a temperature estimation means for estimating a temperature of cooling water in the vicinity of a cylinder head in the engine, wherein the opening / closing instruction means However, it is preferable to instruct the opening and closing of the shutoff valve based on the temperature of the cooling water estimated by the temperature estimating means.

  According to the cooling device having such a configuration, the temperature of the cooling water in the vicinity of the cylinder head in the engine is estimated, and the opening / closing of the shut-off valve is instructed based on the estimated temperature of the cooling water. Can be opened and closed properly.

  That is, for example, when the temperature of the cooling water in the vicinity of the cylinder head is high (for example, 90 ° C. or higher), the shut-off valve is opened and the cooling water is circulated through the first circulation path passing through the engine and the heater core. By increasing the cooling capacity in the vicinity of the cylinder head, piston hitting noise can be suppressed. On the other hand, when the temperature of the cooling water in the vicinity of the cylinder head is low (for example, less than 90 ° C.), the shutoff valve is closed to stop the circulation of the cooling water in the first circulation path via the engine and the heater core. Warming up can be promoted.

  The cooling device according to the present invention further includes a temperature sensor for detecting the temperature of the cooling water on the downstream side of the cylinder head, and the temperature estimation means is based on the temperature of the cooling water detected by the temperature sensor, It is preferable to estimate the temperature of the cooling water in the vicinity of the cylinder head.

  According to the cooling device having such a configuration, the temperature sensor detects the temperature of the cooling water on the downstream side of the cylinder head, and estimates the temperature of the cooling water in the vicinity of the cylinder head based on the detected temperature of the cooling water. Therefore, since the temperature of the cooling water in the vicinity of the cylinder head can be accurately estimated, the shutoff valve can be opened and closed more appropriately.

  According to the cooling device of the present invention, the cooling water that circulates through the first circulation path, which is the circulation path of the cooling water that does not pass through the radiator, passes through the engine by shutting off the shutoff valve. Thus, since the cooling water circulating through the second circulation path, which is the cooling water circulation path via the engine and the throttle body, can be conducted, warm-up can be promoted and the throttle body can be prevented from freezing. Further, since the second circulation path is formed in the engine block so as to communicate with the upper part thereof, it is possible to suppress piston hitting sound.

It is a block diagram which shows an example of the cooling device which concerns on this invention. It is a longitudinal cross-sectional view which shows an example of the outflow port of the cooling water in the engine block of the 2nd circulation path shown in FIG. It is a cross-sectional view which shows an example of the outflow port of the cooling water in the engine block of the 2nd circulation path shown in FIG. It is a functional block diagram which shows an example of a structure of the functional structure in ECU shown in FIG. It is a figure which shows an example of the state of the cooling device shown in FIG. 1 when an engine is a warm-up operation state. It is a graph which shows an example of the suppression effect of the piston hitting sound in the cooling device shown in FIG. It is a figure which shows an example of the state of the cooling device shown in FIG. 1 when an engine is not a warming-up operation state. 5 is a flowchart showing an example of the operation of the ECU shown in FIG. It is a block diagram which shows an example of the cooling device which concerns on other embodiment of this invention. It is a figure which shows an example of the state of the cooling device shown in FIG. 7 when an engine is a warm-up operation state. It is a figure which shows an example of the state of the cooling device shown in FIG. 7 when an engine is not a warming-up operation state. It is a block diagram which shows an example of the conventional cooling device.

-Configuration of conventional cooling device 300-
Before describing the embodiment of the present invention, the configuration of a conventional cooling device will be described with reference to FIG. FIG. 12 is a configuration diagram illustrating an example of a conventional cooling device 300. As shown in FIG. 12, the cooling water circulation path includes a thermostat 11, a water pump 1 </ b> A, an engine 2, a heater core 41, an EGR cooler 42, an exhaust heat recovery device 43, a throttle body 51, an EGR valve 52, and a radiator 6. Is arranged.

  The thermostat 11, the engine 2, the heater core 41, the EGR cooler 42, the exhaust heat recovery device 43, the throttle body 51, the EGR valve 52, and the radiator 6 shown in FIG. 12 are respectively the thermostat 11, the engine 2, and the heater core shown in FIG. 41, the EGR cooler 42, the exhaust heat recovery device 43, the throttle body 51, the EGR valve 52, and the radiator 6 have substantially the same configuration, and will be described later with reference to FIG.

  The water pump 1A is a pump that circulates cooling water, and is a variable flow rate pump that is configured so that the discharge flow rate can be controlled. Further, the water pump 1A controls the discharge flow rate based on an instruction from an unillustrated ECU. In the conventional cooling device 300, as will be described later, when the engine is in a warm-up operation state, the water pump 1A is flowed to control the discharge flow rate to a minute flow rate (for example, 1 liter per minute). It is necessary to use a variable pump.

  In addition, the cooling device 300 includes a cooling water pipe P51, a cooling water pipe P52, a heater core 41, a cooling water pipe P53, a cooling water pipe P54, an EGR cooler 42, a cooling water pipe P56, a cooling water pipe P58, and a cooling water pipe from the engine 2. A first circulation path that returns to the water pump 1A via the P62 and the thermostat 11 in order is provided. In the first circulation path, the cooling water pipe P55, the exhaust heat recovery device 43, and the cooling water pipe P57 are connected in parallel with the cooling water pipe P54, the EGR cooler 42, and the cooling water pipe P56.

  Further, the cooling device 300 sequentially passes the water pump from the engine 2 through the cooling water pipe P51, the cooling water pipe P59, the throttle body 51, the cooling water pipe P60, the EGR valve 52, the cooling water pipe P62, and the thermostat 11. A second circulation path returning to 1A is provided.

  In addition, the cooling device 300 includes a third circulation path that returns from the engine 2 to the water pump 1A via the cooling water pipe P63, the radiator 6, the cooling water pipe P64, and the thermostat 11 in order.

  When the engine is in a warm-up operation state, by controlling the discharge flow rate of the water pump 1A to a minute flow rate (for example, 1 liter per minute), warm-up is promoted and the throttle body 51 is prevented from freezing. be able to. However, the upper part of the cylinder bore of the engine 2 becomes high temperature and deforms due to thermal expansion, which may increase piston hitting sound.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a cooling device that promotes warm-up, prevents freezing of the throttle body 51, and can suppress piston hitting sound. It is said. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

-Configuration of cooling device 100-
FIG. 1 is a configuration diagram showing an example of a cooling device 100 according to the present invention. First, the circulation path of the cooling water in the cooling device 100 will be described with reference to FIG. As shown in FIG. 1, the cooling water circulation path includes a water pump 1, a thermostat 11, an engine 2, an electric valve 3, a heater core 41, an EGR cooler 42, an exhaust heat recovery device 43, a throttle body 51, an EGR valve 52, And the radiator 6 is arrange | positioned.

  The water pump 1 circulates the cooling water in the cooling water circulation path. In the cooling device 300 shown in FIG. 12, the water pump 1A needs to be a variable flow rate pump, but the water pump 1 does not need to have a variable discharge flow rate. That is, the water pump 1 may be a variable flow rate pump or a pump that is not a variable flow rate pump (for example, a general mechanical pump). In the latter case, the apparatus can be simplified.

  The thermostat 11 shuts off or conducts the water path between the radiator 6 and the water pump 1. For example, the thermostat 11 uses a thermo wax that expands and contracts according to the temperature of the cooling water as a driving source. ) Can be driven. Specifically, when the cooling water temperature is relatively low (for example, less than 80 ° C.), the thermostat 11 shuts off the water channel between the radiator 6 and the water pump 1 by closing the valve. The cooling water is not allowed to flow through the radiator 6. On the other hand, when the cooling water temperature is relatively high (for example, 80 ° C. or higher), the thermostat 11 opens the valve to conduct the water path between the radiator 6 and the water pump 1, and the radiator By flowing a part of the cooling water through 6, the heat recovered by the cooling water is released to the atmosphere by the radiator 6.

  The engine 2 includes a plurality of (for example, four) cylinder bores 281 to 284 (see FIG. 3), each of which has a piston inserted therein and forms a combustion chamber, and functions as a vehicle drive source. The engine 2 includes a water jacket 22 that cools the cylinder bore wall. The water jacket 22 is configured to be able to supply cooling water from the water pump 1 via the water channel 21.

  Three cooling water pipes P <b> 11, P <b> 18 and P <b> 22 are connected to the cooling water downstream side of the water jacket 22. The cooling water pipe P <b> 11 is a pipe that conveys the cooling water from the water jacket 22 to the heater core 41, the EGR cooler 42, and the exhaust heat recovery unit 43. The cooling water pipe P <b> 18 is a pipe that conveys the cooling water from the water jacket 22 to the throttle body 51 and the EGR valve 52. Moreover, the electric valve 3 is interposed in the cooling water pipe P11. The cooling water pipe P <b> 22 is a pipe that conveys the cooling water from the water jacket 22 to the radiator 6.

  Further, water passages 23, 24, 25 connected from the water jacket 22 to the cooling water pipes P 11, P 22 are formed in the engine 2. The water channel 23 is formed on the downstream side of the cooling water of the water jacket 22, and the downstream side of the cooling water of the water channel 23 is branched and connected to the water channels 24 and 25. The water channels 24 and 25 are connected to the cooling water pipes P22 and P11, respectively. A water temperature sensor 27 is disposed in the vicinity of the water channel 23. Further, the engine 2 is formed with a water channel 26 connected from the water jacket 22 to the cooling water pipe P18.

  The water temperature sensor 27 detects the temperature of the cooling water downstream of the water jacket 22 (here, the water passage 23). The detected temperature signal is output to an ECU 7 described later (a water temperature detection unit 71 described later using FIG. 4). Here, the water temperature sensor 27 corresponds to the temperature sensor described in the claims. In the present embodiment, the case where the water temperature sensor 27 is disposed in the water passage 23 on the downstream side of the cooling water of the water jacket 22 will be described. However, the water temperature sensor 27 may be disposed in the water jacket 22 or the like. Good.

  The heater core 41 uses the heat of the cooling water discharged from the water jacket 22 to heat the passenger compartment, and is disposed facing the air duct of the air conditioner. That is, the air-conditioned air flowing in the air duct is passed through the heater core 41 when the vehicle interior is heated and supplied to the vehicle interior as warm air, while in other cases (for example, during cooling), the air-conditioned air passes through the heater core 41. Configured to bypass. The cooling water that has passed through the heater core 41 is supplied to the EGR cooler 42 and the exhaust heat recovery unit 43 via the cooling water pipes P12 and P13 or the cooling water pipes P12 and P14.

  The EGR (Exhaust Gas Recirculation) cooler 42 is disposed in an EGR passage that recirculates part of the exhaust gas to the intake system, and cools the exhaust gas that passes (refluxs) the EGR passage. Here, the EGR passage is used to reduce the combustion temperature by reducing a part of the exhaust gas to the intake system and supplying the exhaust gas again to the combustion chamber of the engine 2, thereby reducing the amount of NOx generated. The EGR passage is provided with an EGR valve 52 that is controlled to be opened and closed by electronic control and adjusts the flow rate of exhaust gas flowing through the EGR passage.

  The exhaust heat recovery unit 43 recovers the heat of the exhaust gas discharged from the engine 2 and promotes the temperature rise of the cooling water. Cooling water pipes P15 and P16 are connected to the cooling water downstream sides of the EGR cooler 42 and the exhaust heat recovery unit 43, respectively, and the cooling water pipes P15 and P16 merge to be connected to the cooling water pipe P17. Furthermore, the cooling water pipe P17 and the cooling water pipe P20 connected to the cooling water downstream side of the EGR valve 52 merge to be connected to the cooling water pipe P21, and the cooling water pipe P21 passes through the thermostat 11. It is connected to the water pump 1.

  In this way, a first circulation path configured to circulate the cooling water via the engine 2 and the heater core 41 is formed. That is, in the first circulation path, the cooling water discharged from the water pump 1 is the engine 2, the cooling water pipe P11 (electric valve 3), the heater core 41, the cooling water pipes P12, P13 (or the cooling water pipes P12, P14). ), The EGR cooler 42, the cooling water pipe P15 (or the exhaust heat recovery device 43, the cooling water pipe P16), and the cooling water pipes P17 and P21 in sequence, and then return to the water pump 1 via the thermostat 11. .

  In the present embodiment, the case where the first circulation path is a circulation path configured to be able to circulate cooling water via the engine 2 and the heater core 41 will be described. However, the first circulation path passes through the engine 2. The circulation path may be configured so that the cooling water can be circulated without passing through the radiator 6. For example, the first circulation path may be a circulation path configured to be able to circulate cooling water via the engine 2 and the EGR cooler 42 (or the exhaust heat recovery unit 43). Further, for example, the first circulation path is a circulation path configured to circulate cooling water via the engine 2 without passing through the cooling device such as the radiator 6 and the heater core 41, the exhaust heat recovery device, or the like. A certain form may be sufficient. In other words, the first circulation path may be a circulation path that bypasses the radiator 6.

  The throttle body 51 is provided on the downstream side of the air cleaner in the intake passage of the engine 2 and adjusts the intake air amount. Specifically, the throttle body 51 includes a throttle valve such as a butterfly valve, a throttle motor that opens and closes the throttle valve, and a throttle opening sensor that detects the opening of the throttle valve.

  An EGR valve 52 is connected to the downstream side of the cooling water of the throttle body 51 via a cooling water pipe P19. The cooling water pipe P20 is connected to the cooling water downstream side of the EGR valve 52, and the cooling water pipe P20 joins the cooling water pipe P17 connected to the cooling water downstream side of the EGR cooler 42 and the exhaust heat recovery unit 43. And it is connected to the cooling water piping P21.

  In this way, a second circulation path configured to circulate cooling water via the engine 2 and the throttle body 51 is formed. That is, in the second circulation path, the cooling water discharged from the water pump 1 sequentially passes through the engine 2, the cooling water pipe P18, the throttle body 51, the cooling water pipe P19, the EGR valve 52, and the cooling water pipes P20 and P21. Via, return to the water pump 1 via the thermostat 11.

  The electric valve 3 is a valve for conducting and blocking the cooling water in the cooling water pipe P11, and is controlled to open and close in accordance with an instruction from the ECU 7 (an opening / closing instruction unit 74 described later with reference to FIG. 4). The electric valve 3 corresponds to a “shutoff valve” described in the claims. Specifically, when the engine 2 is in a warm-up operation state, the electric valve 3 is closed, and the first circulation path configured to circulate cooling water via the engine 2 and the heater core 41 is provided. Cooling water circulation is interrupted. Further, in this case, the cooling water is circulated through the second circulation path configured to be able to circulate the cooling water via the engine 2 and the throttle body 51. On the other hand, when the engine 2 is not in the warm-up operation state, the electric valve 3 is opened, and the cooling water is also provided in the first circulation path configured to circulate the cooling water via the engine 2 and the heater core 41. Is circulated.

  In this way, by closing the electric valve 3, the coolant that circulates through the first circulation path, which is the circulation path of the coolant that passes through the engine 2 and the heater core 41, is shut off, and the engine 2 and the throttle body Since the cooling water that circulates through the second circulation path that is the circulation path of the cooling water passing through 51 can be conducted, warm-up can be promoted, and the throttle body 51 and the EGR valve 52 can be prevented from freezing. .

  In the present embodiment, the case where the “shutoff valve” described in the claims is the electric valve 3 will be described. However, the “shutoff valve” is another type of shutoff valve (for example, a negative pressure valve driven by a negative pressure). Etc.).

  In the present embodiment, the case where the throttle body 51 is connected to the upstream side of the cooling water and the EGR valve 52 is arranged on the downstream side in the second circulation path will be described. Any form in which the body 51 and the EGR valve 52 are disposed may be used. For example, in the second circulation path, an EGR valve 52 may be connected to the upstream side of the cooling water, and the throttle body 51 may be disposed on the downstream side. For example, in the second circulation path, the EGR valve 52 and the throttle body 51 may be connected in parallel to the downstream side of the cooling water pipe P18.

  The radiator 6 cools the cooling water by exchanging heat between the cooling water and the outside air (running air and air blown by driving the cooling fan) and radiating heat to the outside air. The cooling water downstream side of the radiator 6 is connected to the thermostat 11 via the cooling water pipe P23.

  In this way, a third circulation path configured to circulate the cooling water via the engine 2 and the radiator 6 is formed. That is, in the third circulation path, the cooling water discharged from the water pump 1 sequentially passes through the engine 2, the cooling water pipe P22, the radiator 6, and the cooling water pipe P23, and then passes through the thermostat 11 and the water pump. Return to 1.

-About the configuration of the second circulation path-
The second circulation path configured to be able to circulate the cooling water via the engine 2 and the throttle body 51 circulates through the second circulation path when the water pump 1 that circulates the cooling water is driven. The flow rate of the cooling water is configured to be equal to or lower than a preset flow rate threshold value (for example, 2 liters / minute).

  As described above, when the water pump 1 that circulates the cooling water is being driven, the flow rate of the cooling water that circulates through the second circulation path is equal to or less than the preset flow rate threshold value. By setting (for example, 2 liters / minute), warm-up can be promoted.

  Specifically, in the present embodiment, the cooling water pipes P18, P19, and P20 constituting the second circulation path are set to have a diameter that is equal to or smaller than a preset diameter threshold value, thereby cooling the second circulation path. The flow rate of water is configured to be equal to or lower than a preset flow rate threshold value (for example, 2 liters / minute).

  In this way, since the diameters of the cooling water pipes P18, P19, and P20 constituting the second circulation path are set to be equal to or smaller than the preset diameter threshold value, the diameter threshold value is set to an appropriate value (for example, 10 mm). By setting, warm-up can be promoted with a simple configuration. Here, the diameters of the cooling water pipes P18, P19, and P20 are set to 8 mm, for example.

  That is, for example, when controlling the flow rate of the water pump that circulates the cooling water so that the flow rate of the cooling water that circulates in the second circulation path is less than or equal to a preset flow rate threshold value, the water pump is a variable flow rate pump. (See FIG. 12). On the other hand, by setting the diameters of the cooling water pipes P18, P19, P20 constituting the second circulation path to be equal to or smaller than a preset diameter threshold value, and setting the diameter threshold value to an appropriate value (for example, 10 mm), When the flow rate of the cooling water circulating through the two circulation paths is set to a preset flow rate threshold value (for example, 2 liters / minute) or less, the water pump 1 does not need to be a variable flow rate pump, so the configuration is simple. Warm-up can be promoted.

  In this embodiment, the case where the flow rate of the cooling water circulating through the second circulation path is set to be equal to or less than the flow rate threshold by setting the diameters of the cooling water pipes P18, P19, and P20 to be equal to or less than the diameter threshold value will be described. The form which makes the flow volume of the cooling water which circulates through a 2nd circulation path below a flow volume threshold value by the method of this. For example, a configuration may be provided in which means (for example, a throttle valve, an orifice, etc.) for limiting the flow rate of the cooling water circulating through the second circulation path to a flow rate threshold value or less.

  Next, the arrangement positions of the water passage 26 and the cooling water pipe P18 constituting the second circulation path will be described with reference to FIGS. FIG. 2 is a longitudinal sectional view showing an example of the coolant outlet in the engine block 2A in the second circulation path shown in FIG. FIG. 3 is a cross-sectional view showing an example of the coolant outlet in the engine block 2A in the second circulation path shown in FIG.

  As shown in FIG. 2, the water jacket 22 is formed along the side surface of the cylinder bore 28 (here, the cylinder bores 281 to 284 shown in FIG. 3 are collectively referred to as the cylinder bore 28). Further, a water passage 26 communicating with the water jacket 22 is formed in the vicinity of the upper end portion of the engine block 2A (that is, in the vicinity of the cylinder head, not shown). It is connected.

  As described above, the water passage 26 and the cooling water pipe P18 constituting the second circulation path are configured to communicate with the upper portion (here, the vicinity of the upper end portion of the engine block 2A) of the engine block 2A. The hitting sound can be suppressed.

  That is, the piston hitting sound is generated when the upper part of the cylinder bore 28 becomes hot and deforms due to thermal expansion, and is formed by communicating with the upper part of the engine block 2A (here, near the upper end part of the engine block 2A). In addition, since the upper portion of the cylinder bore 28 is cooled by the cooling water flowing through the second circulation path, it is possible to suppress the piston hitting sound.

  In the present embodiment, the case where the water passage 26 and the cooling water pipe P18 constituting the second circulation path are disposed in the vicinity of the upper end portion of the engine block 2A will be described. The cooling water pipe P18 only needs to be disposed in the upper part of the engine block 2A.

  Further, as shown in FIG. 3, a water channel 26 (corresponding to an outlet of cooling water in the engine block 2A) constituting the second circulation path is a water channel 21 (cooling to the engine block 2A) formed in the engine block 2A. (Corresponding to the water inlet). Here, the water channel 21 is formed at the lower left end of the engine block 2A in FIG. 3, and the water channel 26 is formed at the upper right end of the engine block 2A in FIG.

  In this case, as indicated by an arrow in FIG. 3, the cooling water flowing into the water jacket 22 from the water channel 21 passes through the outer periphery of the cylinder bores 281, 282, 283, 284 in order in the water jacket 22. 26 is discharged. Therefore, the upper part of the cylinder bore 28 can be cooled more efficiently.

  In the present embodiment, the case where the water channel 26 is formed at the upper right end of the engine block 2 </ b> A has been described, but the water channel 26 may be formed on the side away from the water channel 21. For example, as shown by a broken line in FIG. 3, the water channel 26 may be formed at the right end in FIG. 3 of the engine block 2A.

-ECU7-
Next, the configuration of the ECU 7 will be described with reference to FIG. FIG. 4 is a functional configuration diagram illustrating an example of a functional configuration in the ECU 7 illustrated in FIG. 1. Here, the ECU 7 controls the electric valve 3 and the like, and includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a backup RAM.

  The ROM stores various control programs and table data (or map data) that is referred to when the various control programs are executed. The CPU performs various processes by reading and executing various control programs stored in the ROM. The RAM is a memory that temporarily stores data input from each sensor as a result of processing by the CPU. The backup RAM is a non-volatile memory that stores data to be saved when the engine 2 is stopped, for example.

  The ECU 7 is connected to a water temperature sensor 27, an engine speed sensor 271 that detects the rotational speed Ne of the engine 2, an intake air amount sensor 272 that detects an intake air amount Qi supplied to the engine 2, and the like. Detection signals from the engine speed sensor 271 and the intake air amount sensor 272 are input to the ECU 7. Moreover, the electric valve 3 etc. are connected to ECU7 as a control object.

  In the ECU 7, the CPU functionally functions as a water temperature detection unit 71, a torque estimation unit 72, a temperature estimation unit 73, and an opening / closing instruction unit 74 by reading and executing a control program stored in the ROM. To do. The cooling device 100 according to the present invention includes a water temperature detection unit 71, a torque estimation unit 72, a temperature estimation unit 73, and an opening / closing instruction unit 74.

  The water temperature detection unit 71 is a functional unit that detects the temperature Tw of the cooling water downstream of the water jacket 22 (here, the water channel 23) via the water temperature sensor 27.

  The torque estimation unit 72 is a functional unit that estimates the output torque Tr of the engine 2 based on the engine speed Ne detected by the engine speed sensor 271 and the intake air amount Qi detected by the intake air amount sensor 272. . Here, the torque estimation unit 72 corresponds to a part of “temperature estimation means” described in the claims.

  The temperature estimation unit 73 includes a cooling water temperature Tw on the downstream side of the water jacket 22 (here, the water passage 23) detected by the water temperature detection unit 71, an engine speed Ne detected by the engine speed sensor 271, Further, it is a functional unit that estimates the temperature Ts of the cooling water in the vicinity of the cylinder head in the engine 2 based on the output torque Tr of the engine 2 estimated by the torque estimating unit 72. Here, the temperature estimation unit 73 corresponds to a part of “temperature estimation means” recited in the claims.

  The opening / closing instruction unit 74 is a functional unit that instructs opening / closing of the electric valve 3 based on the temperature Ts estimated by the temperature estimation unit 73. Here, the opening / closing instruction unit 74 corresponds to “opening / closing instruction means” described in the claims. Specifically, the opening / closing instruction unit 74 determines that the engine 2 is not in the warm-up operation state when the temperature Ts is equal to or higher than a preset threshold temperature Tsth (for example, 90 ° C.), and the electric valve 3 is opened, and when the temperature Ts is lower than the threshold temperature Tsth, it is determined that the engine 2 is in the warm-up operation state, and the electric valve 3 is closed.

  Thus, the temperature Ts of the cooling water in the vicinity of the cylinder head in the engine 2 is estimated, and the opening / closing of the electric valve 3 is instructed based on the estimated temperature Ts of the cooling water. Can be opened and closed.

  That is, for example, when the temperature Ts of the cooling water in the vicinity of the cylinder head is high (for example, 90 ° C. or higher), the electric valve 3 is opened and the first circulation path passing through the engine 2 and the heater core 41 is cooled. By circulating the water and increasing the cooling capacity in the vicinity of the cylinder head, the engine 2 can be properly cooled, and the cooling water can be supplied via the heater core 41, the EGR cooler 42, and the exhaust heat recovery unit 43. Can circulate. On the other hand, when the temperature Ts of the cooling water in the vicinity of the cylinder head is low (for example, less than 90 ° C.), the electric valve 3 is closed and the cooling water in the first circulation path passing through the engine 2 and the heater core 41 is used. Circulation can be stopped and warm-up can be promoted.

  Further, the coolant temperature Tw is detected by the water temperature sensor 27 on the downstream side of the cylinder head, and the coolant temperature Ts in the vicinity of the cylinder head is estimated based on the detected coolant temperature Tw. Since the temperature Ts of the cooling water in the vicinity of the head can be accurately estimated, the electric valve 3 can be opened and closed more appropriately.

  In the present embodiment, the temperature estimation unit 73 determines whether the engine 2 is based on the temperature Tw of the cooling water downstream of the water jacket 22 (here, the water passage 23), the engine speed Ne, and the engine output torque Tr. Although the case where the temperature Ts of the coolant near the cylinder head in the engine is estimated has been described, the temperature estimation unit 73 may estimate the temperature Ts of the coolant near the cylinder head in the engine 2 by other methods.

  For example, a temperature sensor that detects the temperature Ts of the cooling water in the vicinity of the cylinder head in the engine 2 is provided, and the temperature estimation unit 73 detects the temperature of the cooling water in the vicinity of the cylinder head in the engine 2 based on the detected temperature Ts. A form for estimating Ts may be used. In this case, the temperature Ts of the coolant near the cylinder head in the engine 2 can be accurately estimated.

-When warming up-
FIG. 5 is a diagram illustrating an example of the state of the cooling device 100 illustrated in FIG. 1 when the engine 2 is in a warm-up operation state. When the engine 2 is in the warm-up operation state, the electric valve 3 is closed by the open / close instruction unit 74 of the ECU 7. Therefore, the cooling water that circulates through the first circulation path that is the circulation path of the cooling water that passes through the engine 2 and the heater core 41 is blocked. On the other hand, the cooling water that circulates through the second circulation path, which is the circulation path of the cooling water that passes through the engine 2 and the throttle body 51, is conducted, and the cooling water circulates as indicated by solid arrows in the figure. Therefore, warm-up can be promoted and the throttle body 51 and the EGR valve 52 can be prevented from freezing.

  FIG. 6 is a graph showing an example of the effect of suppressing the piston hitting sound in the cooling device shown in FIG. The horizontal axis in the figure is the elapsed time after the engine 2 is started, and the vertical axis is the amplitude of the vibration of the outer wall constituting the engine block 2A (here, the vibration having a frequency in the range of 1 kHz to 5 kHz). . A graph G1 indicated by a broken line indicates that when the engine 2 is in a warm-up operation state, the cooling water circulating through the second circulation path, which is the circulation path of the cooling water passing through the engine 2 and the throttle body 51, is interrupted (for example, It is a graph which shows the change of the amplitude when water pump 1 is stopped. A graph G2 indicated by a solid line indicates cooling that circulates through a second circulation path that is a circulation path of cooling water passing through the engine 2 and the throttle body 51 as shown in FIG. 5 when the engine 2 is in a warm-up operation state. It is a graph which shows the change of amplitude motion at the time of conducting water.

  When the cooling water circulating through the second circulation path is shut off, as shown in the graph G1, the amplitude suddenly increases and the piston hitting sound increases. On the other hand, when the cooling water circulating through the second circulation path is conducted, the increase in amplitude is suppressed and the piston hitting sound does not increase as shown in the graph G2. In this way, piston striking sound can be effectively suppressed by conducting the cooling water circulating through the second circulation path.

-When not in warm-up mode-
FIG. 7 is a diagram illustrating an example of the state of the cooling device 100 illustrated in FIG. 1 when the engine 2 is in a warm-up operation state. However, the case where the water path between the radiator 6 and the water pump 1 is interrupted by the thermostat 11 will be described here for convenience.

  When the engine 2 is not in the warm-up operation state, the electric valve 3 is opened by the opening / closing instruction unit 74 of the ECU 7. Therefore, the cooling water that circulates through the first circulation path that is the circulation path of the cooling water that passes through the engine 2 and the heater core 41 is conducted, and the cooling water circulates as indicated by the dashed arrows in the figure. Further, the cooling water circulating through the second circulation path, which is the cooling water circulation path passing through the engine 2 and the throttle body 51, is also conducted, and the cooling water circulates as shown by solid arrows in the figure. Therefore, the engine 2 can be properly cooled and the cooling water can be circulated through the heater core 41, the EGR cooler 42, and the exhaust heat recovery unit 43.

-Operation of ECU7-
FIG. 8 is a flowchart showing an example of the operation of the ECU shown in FIG. First, in step S <b> 101, the water temperature detection unit 71 detects the temperature Tw of the cooling water on the downstream side of the cooling water of the water jacket 22 (here, the water channel 23) via the water temperature sensor 27. In step S103, the torque estimating unit 72 acquires the engine speed Ne detected by the engine speed sensor 271. Next, in step S <b> 105, the intake air amount Qi detected by the intake air amount sensor 272 is acquired by the torque estimating unit 72.

  Next, in step S107, the torque estimation unit 72 estimates the output torque Tr of the engine 2 based on the engine speed Ne acquired in step S103 and the intake air amount Qi acquired in step S105. In step S109, the temperature estimation unit 73 sets the cooling water temperature Tw detected in step S101, the engine speed Ne acquired in step S103, and the output torque Tr of the engine 2 estimated in step S107. Based on this, the temperature Ts of the coolant near the cylinder head in the engine 2 is estimated.

  Next, in step S111, the opening / closing instruction unit 74 determines whether or not the temperature Ts estimated in step S109 is equal to or higher than a threshold temperature Tsth (for example, 90 ° C.). If YES in step S111, the process proceeds to step S113. On the other hand, if NO at step S111, the process proceeds to step S115.

  In step S113, the open / close instruction unit 74 determines that the engine 2 is not in the warm-up operation state, the electric valve 3 is opened, and the process returns to step S101. And the process after step S101 is repeatedly performed. In step S115, the opening / closing instruction unit 74 determines that the engine 2 is in a warm-up operation state, the electric valve 3 is closed, and the process returns to step S101. And the process after step S101 is repeatedly performed.

  Thus, the temperature Ts of the cooling water in the vicinity of the cylinder head in the engine 2 is estimated, and the opening / closing of the electric valve 3 is instructed based on the estimated temperature Ts of the cooling water. Can be opened and closed.

-Configuration of cooling device 200-
Next, with reference to FIGS. 9-11, the structure of the cooling device 200 which concerns on other embodiment of this invention is demonstrated. FIG. 9 is a configuration diagram illustrating an example of a cooling device 200 according to another embodiment of the present invention. In the following description, among the configurations of the cooling device 200, configurations that are common to the cooling device 100 are denoted by the same reference numerals, and description thereof is simplified.

  First, a configuration common to the cooling device 100 among the configurations of the cooling device 200 will be described. As with the cooling device 100, the cooling device 200 includes a water pump 1, a thermostat 11, an engine 2, an electric valve 3, a heater core 41, an EGR cooler 42, an exhaust heat recovery device 43, a throttle body 51, and a cooling water circulation path. An EGR valve 52 and a radiator 6 are provided. Further, water passages 21, 23, 24, 25, 26 and a water jacket 22 are formed in the engine 2. Further, a water temperature sensor 27 is disposed in the vicinity of the water channel 23. In addition, an ECU 7 that controls opening and closing of the electric valve 3 is provided.

  Next, a configuration different from the cooling device 100 among the configurations of the cooling device 200 will be described. The cooling device 200 is configured such that the second circulation path configured to be able to circulate the cooling water via the engine 2 and the throttle body 51 is configured to be able to circulate the cooling water via the exhaust heat recovery device 43. Is different from the cooling device 100 in FIG. This point will be described in detail below.

  First, in the cooling device 200, as shown in FIG. 9, in the first circulation path, the cooling water discharged from the water pump 1 is the engine 2, the cooling water pipe P31 (electric valve 3), the heater core 41, and the cooling water pipe. Thermostat through P32, P33 (or cooling water piping P32, P35), EGR cooler 42, cooling water piping P36 (or exhaust heat recovery device 43, cooling water piping P37), and cooling water piping P38 in order. 11 to return to the water pump 1.

  In the second circulation path, the cooling water discharged from the water pump 1 is the engine 2, the cooling water pipe P39, the throttle body 51, the cooling water pipe P40, the EGR valve 52, the cooling water pipe P41, and the exhaust heat recovery unit 43. Then, the cooling water pipe P37 and the cooling water pipe P38 are sequentially passed back to the water pump 1 via the thermostat 11.

  That is, the cooling device 200 is different from the cooling device 100 in that the exhaust heat recovery device 43 is included in the second circulation path. Specifically, the cooling water pipe P41 connected to the cooling water downstream side of the EGR valve 52 in the second circulation path is connected to the cooling water upstream end of the exhaust heat recovery unit 43.

  Moreover, the flow rate of the cooling water circulating through the second circulation path is set in advance by setting the diameters of the cooling water pipes P39, P40, and P41 constituting the second circulation path to be equal to or less than a preset diameter threshold value. The flow rate is set to be equal to or lower than the flow rate threshold (for example, 2 liters / minute).

  In this way, since the diameters of the cooling water pipes P39, P40, and P41 constituting the second circulation path are set to be equal to or smaller than the preset diameter threshold value, the diameter threshold value is set to an appropriate value (for example, 10 mm). By setting, warm-up can be promoted with a simple configuration. Here, the diameters of the cooling water pipes P39, P40, and P41 are set to 8 mm, for example.

  In the present embodiment, the case where the throttle body 51, the EGR valve 52, and the exhaust heat recovery device 43 are arranged in order from the upstream side of the cooling water in the second circulation path will be described. The throttle body 51 and the EGR valve 52 need only be connected. For example, in the second circulation path, an EGR valve 52, an exhaust heat recovery device 43, and a throttle body 51 may be arranged in order from the upstream side of the cooling water. Further, for example, in the second circulation path, the EGR valve 52, the throttle body 51, and the exhaust heat recovery device 43 may be connected in parallel to the downstream side of the cooling water pipe P39.

-When warming up-
FIG. 10 is a diagram illustrating an example of the state of the cooling device 200 illustrated in FIG. 9 when the engine 2 is in a warm-up operation state. When the engine 2 is in the warm-up operation state, the electric valve 3 is closed by the open / close instruction unit 74 of the ECU 7. Therefore, the cooling water that circulates through the first circulation path that is the circulation path of the cooling water that passes through the engine 2 and the heater core 41 is blocked. On the other hand, the cooling water that circulates through the second circulation path, which is the circulation path of the cooling water that passes through the engine 2 and the throttle body 51, is conducted, and the cooling water circulates as indicated by solid arrows in the figure.

  Therefore, warm-up can be promoted and the throttle body 51 and the EGR valve 52 can be prevented from freezing. In addition, since the second circulation path is configured to be able to circulate the cooling water via the exhaust heat recovery unit 43, boiling of the cooling water in the exhaust heat recovery unit 43 can be avoided.

-When not in warm-up mode-
FIG. 11 is a diagram illustrating an example of the state of the cooling device 200 illustrated in FIG. 9 when the engine 2 is in a warm-up operation state. However, the case where the water path between the radiator 6 and the water pump 1 is interrupted by the thermostat 11 will be described here for convenience.

  When the engine 2 is not in the warm-up operation state, the electric valve 3 is opened by the opening / closing instruction unit 74 of the ECU 7. Therefore, the cooling water that circulates through the first circulation path that is the circulation path of the cooling water that passes through the engine 2 and the heater core 41 is conducted, and the cooling water circulates as indicated by the dashed arrows in the figure. Further, the cooling water circulating through the second circulation path, which is the cooling water circulation path passing through the engine 2 and the throttle body 51, is also conducted, and the cooling water circulates as shown by solid arrows in the figure. Therefore, the engine 2 can be properly cooled and the cooling water can be circulated through the heater core 41, the EGR cooler 42, and the exhaust heat recovery unit 43.

-Other embodiments-
In the present embodiment, the case where the water temperature detection unit 71, the torque estimation unit 72, the temperature estimation unit 73, and the opening / closing instruction unit 74 constituting the cooling device are all realized as functional units in the ECU 7 has been described. At least one of the part 71, the torque estimation part 72, the temperature estimation part 73, and the opening / closing instruction | indication part 74 may be comprised with hardware, such as an electronic circuit.

  The present invention can be used for a cooling device that restricts the flow rate of cooling water that circulates through an engine when the engine is in a warm-up operation state.

DESCRIPTION OF SYMBOLS 100, 200 Cooling device 1 Water pump 11 Thermostat 2 Engine 2A Engine block 22 Water jacket 27 Water temperature sensor 3 Electric valve 41 Heater core 42 EGR cooler 43 Exhaust heat recovery device 51 Throttle body 52 EGR valve 6 Radiator 7 ECU
71 Water temperature detection unit 72 Torque estimation unit (part of temperature estimation means)
73 Temperature estimation part (part of temperature estimation means)
74 Open / close instruction section (open / close instruction means)

Claims (9)

A cooling device that limits the flow rate of cooling water that circulates through the engine when the engine is in a warm-up operation state,
A first circulation path configured to be able to circulate cooling water via an engine and not via a radiator;
A shutoff valve interposed in the first circulation path for conducting or shutting off the cooling water;
A second circulation path that is configured to be able to circulate cooling water via the engine and the throttle body, and is different from the first circulation path,
The second circulation path is formed in the engine block so as to communicate with the upper part thereof. The cooling device according to claim 1, wherein
The cooling apparatus according to claim 1, wherein the second circulation path is formed to communicate with the vicinity of the cylinder head. The cooling device according to claim 1 or 2,
The cooling device according to claim 1, wherein the cooling water outlet of the second circulation path in the engine block is formed on a side away from the cooling water inlet to the engine block. In the cooling device according to any one of claims 1 to 3,
The second circulation path is configured to set the flow rate of the cooling water circulating through the second circulation path to be equal to or lower than a preset flow rate threshold value when the water pump that circulates the cooling water is driven. A cooling device characterized by. The cooling device according to claim 4, wherein
The cooling apparatus according to claim 2, wherein the second circulation path has a diameter of a pipe constituting the second circulation path set to be equal to or smaller than a preset diameter threshold value. In the cooling device according to any one of claims 1 to 5,
The cooling apparatus according to claim 2, wherein the second circulation path is configured to be able to circulate cooling water via an EGR valve. In the cooling device according to any one of claims 1 to 6,
The second circulation path is further configured to be able to circulate cooling water via an exhaust heat recovery device. In the cooling device according to any one of claims 1 to 7,
Open / close instruction means for instructing opening / closing of the shutoff valve;
Temperature estimation means for estimating the temperature of cooling water in the vicinity of the cylinder head in the engine,
The said opening / closing instruction | indication means instruct | indicates opening / closing of the said shut-off valve based on the temperature of the cooling water estimated by the said temperature estimation means. The cooling device according to claim 8, wherein
A temperature sensor for detecting the temperature of the cooling water on the downstream side of the cylinder head;
The cooling device characterized in that the temperature estimation means estimates the temperature of the cooling water in the vicinity of the cylinder head based on the temperature of the cooling water detected by the temperature sensor.

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