JP2017214828A - Cooling water flow rate control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling water flow rate control device for an internal combustion engine that enables reduction of the possibility of deterioration of emissions and fuel economy even when high viscosity LLC is used and even at an ultralow temperature.SOLUTION: A cooling water flow rate control device for an internal combustion engine includes: a first circulation passage section 22 and the like formed by interposing an external device 32 and the like between an outlet section 13out of a cooling water passage 13 and a water pump 40; and a second circulation passage section 24 and the like formed by directly connecting the outlet section and the water pump with each other. An ECU 60 controls a cooling water control valve device 50, so that pressure loss when cooling water flows becomes smaller as detected kinematic viscosity of the cooling water increases, so that a passage area of the second circulation passage section is set to a value larger than zero and a passage area of the first circulation flow passage is set to zero when the kinematic viscosity is predetermined first kinematic viscosity and so that the passage area of the second circulation passage section is set to a maximum value and the passage area of the first circulation passage section is set to a value larger than zero when the kinematic viscosity is predetermined second kinematic viscosity larger than the first kinematic viscosity.SELECTED DRAWING: Figure 1

Description

  The present invention is an internal combustion engine having a cooling water passage inside a main body, and the fuel injection amount is controlled based on the temperature of the cooling water (outlet portion cooling water temperature) in the vicinity of the outlet portion of the main body of the cooling water passage. The present invention relates to a “cooling water flow rate control device for an internal combustion engine” which is applied to an internal combustion engine and controls the flow rate of cooling water flowing through the cooling water passage.

  Conventionally, it has been proposed to use cooling water having a relatively high kinematic viscosity at a low temperature (hereinafter referred to as “Long Life Coolant LLC”) as cooling water (cooling liquid) for an internal combustion engine. (For example, refer to Patent Document 1). Generally, the higher the kinematic viscosity of the cooling water, the smaller the heat transfer coefficient of the cooling water. Therefore, if the high-viscosity LLC is used for cooling the internal combustion engine, the internal combustion engine is hardly cooled when the internal combustion engine is in a normal warm-up process (for example, when the temperature of the cooling water is 25 to 80 ° C.). . As a result, the engine can be warmed up early.

International Publication No. 2013/183161

  By the way, the fuel injection amount of the internal combustion engine is controlled based on the temperature of the cooling water of the engine in consideration of the amount of fuel adhering to the combustion chamber wall surface. For example, the fuel injection amount is increased as the cooling water temperature is lower. On the other hand, it is not easy to arrange a cooling water temperature sensor in the vicinity of the combustion chamber of the internal combustion engine. Therefore, the cooling water temperature sensor is disposed in the vicinity of a portion (hereinafter referred to as “exit portion”) from which the cooling water is discharged from the internal combustion engine body to the outside in the cooling water passage formed in the internal combustion engine body. Established.

  On the other hand, the kinematic viscosity of the high-viscosity LLC is extremely high when the temperature is extremely low (a temperature of 25 ° C. or lower, for example, −30 ° C.), and the heat transfer coefficient of the high-viscosity LLC is extremely small. . Accordingly, when the main body of the internal combustion engine is at a very low temperature, the heat generated in the combustion chamber of the internal combustion engine is difficult to be transmitted to the high viscosity LLC, so that the actual temperature of the combustion chamber wall surface and the cooling detected by the cooling water temperature sensor The deviation from the temperature of the combustion chamber wall surface estimated from the water temperature becomes very large. As a result, when high viscosity LLC is used as cooling water, the fuel injection amount becomes excessive when the main body of the internal combustion engine is at a very low temperature, and the air-fuel ratio of the air-fuel mixture of the internal combustion engine becomes excessively small (over rich). Therefore, the problem that emission and / or fuel consumption deteriorates arises.

  The present invention has been made to address the above-described problems. That is, one of the objects of the present invention is to change the flow rate of the cooling water flowing through the cooling water passage formed in the body of the internal combustion engine according to the kinematic viscosity of the cooling water to be used. A cooling water flow rate control device for an internal combustion engine is provided that is less likely to cause a reduction in emissions and / or fuel consumption even when the internal combustion engine body is at a very low temperature. There is.

  The cooling water flow rate control device of the present invention (hereinafter also referred to as “the present invention device”) is applied to an internal combustion engine (10) having a cooling water passage (13) in a main body (11). In the cooling water passage, one end portion constitutes an inlet portion (13 in) into the main body of the cooling water internal combustion engine, and the other end portion constitutes an outlet portion (13 out) from the main body of the internal combustion engine. Further, the internal combustion engine (10) is based on the coolant temperature (THW) detected by the coolant temperature sensor (61) disposed in the vicinity of the outlet (13out). And is configured to be controlled.

The device of the present invention
An external circulation passage portion (20) for connecting the outlet portion (13out) and the inlet portion (13in) outside the main body (11) of the internal combustion engine to circulate the cooling water;
A water pump (40) that is interposed in the external circulation passage section and that injects the cooling water from the pump inflow section (41, 42), pressurizes the cooling water and discharges it from the pump discharge section (43) ,
A flow rate control unit (50, 60) for changing the flow rate of the cooling water passing through the cooling water passage;
Is provided.

Furthermore, the external circulation passage section (20)
An external device that exchanges heat with the cooling water between the outlet (13out) of the main body of the internal combustion engine and the inflow portions (41, 42) of the water pump (external device other than the heater core (21)) 32, 33, 34) first circulation passage portions (22, 25 and 26; 23, 25 and 26; 27, 28 and 26),
The outlet portion and the inflow portion without interposing an external device for exchanging heat with the cooling water between the outlet portion (13out) of the main body of the internal combustion engine and the inflow portion (41) of the water pump. A second circulation passage portion (24, 25 and 26) formed by directly connecting
Is provided.

  As described above, the high viscosity LLC has a very large viscosity at a very low temperature. When the kinematic viscosity of the cooling water increases, the heat transfer coefficient of the cooling water decreases, so that the heat generated in the combustion chamber of the internal combustion engine is hardly transmitted to the cooling water. Therefore, when the main body of the internal combustion engine is at a very low temperature, the difference between the actual temperature of the combustion chamber wall surface and the temperature of the combustion chamber wall surface estimated from the cooling water temperature detected by the cooling water temperature sensor becomes very large. As a result, when the main body of the internal combustion engine is at a very low temperature, the fuel injection amount becomes excessive, the air-fuel ratio of the air-fuel mixture of the internal combustion engine becomes excessively small, and the emission and / or fuel consumption deteriorates.

Therefore, the flow rate control unit (50, 60)
A first passage area changing unit (52, 53, 55) for changing a first passage area which is a passage area of the first circulation passage in a range from zero to a first maximum value;
A second passage area changing section (54) for changing a second passage area which is a passage area of the second circulation passage in a range from zero to a second maximum value;
A kinematic viscosity detector (60, step 405 to step 420) for detecting the kinematic viscosity (μ) of the cooling water;
The higher the kinematic viscosity detected, the smaller the “pressure loss when the cooling water flows through the external circulation passage”, and
When the detected kinematic viscosity is a predetermined first kinematic viscosity, the second passage area is set to a value larger than zero and the first passage area is set to zero,
When the detected kinematic viscosity is a predetermined second kinematic viscosity greater than the first kinematic viscosity, the second passage area is set to the second maximum value and the first passage area is less than zero. To be set to a large value,
By controlling the first passage area changing unit and the second passage area changing unit, the flow rate of the cooling water flowing through the cooling water passage (13) in the main body of the internal combustion engine as the detected kinematic viscosity increases. A passage area control unit (60, step 425 to step 435, step 450, step 445) for increasing
Is provided.

  According to this, as the kinematic viscosity increases, the flow rate of the cooling water flowing through the cooling water passage (13) in the main body of the internal combustion engine increases, so that the heat generated in the combustion chamber of the internal combustion engine is transmitted to the cooling water. It becomes easy, and the difference between the actual temperature of the combustion chamber wall surface and the temperature of the combustion chamber wall surface estimated from the cooling water temperature detected by the cooling water temperature sensor is reduced. As a result, the above-mentioned “problem that emission and / or fuel consumption deteriorates” can be reduced.

  In addition, the device of the present invention has the first passage area changing portion and the second passage area so that the “pressure loss when cooling water flows through the external circulation passage portion” decreases as the detected kinematic viscosity increases. Control the changing part. Therefore, the flow rate of the cooling water flowing through the cooling water passage (13) can be increased while preventing the energy consumption of the water pump from becoming excessively large.

  Furthermore, the device according to the present invention has a first circulation passage portion provided with an external device for exchanging heat with cooling water and a second circulation passage portion provided with no external device, and has a kinematic viscosity of the cooling water. Is relatively low (while the kinematic viscosity is the first kinematic viscosity), the cooling water is circulated using only the second circulation passage portion. Therefore, the heat of the cooling water is hardly released to the outside by the external device, so that the warm-up of the internal combustion engine can be accelerated.

  In the above description, in order to help understanding of the present invention, names and / or symbols used in the embodiment are attached to the configuration of the invention corresponding to the embodiment described later in parentheses. However, each component of the present invention is not limited to the embodiment defined by the reference numerals. Other objects, other features and attendant advantages of the present invention will be readily understood from the description of the embodiments of the present invention described with reference to the following drawings.

FIG. 1 is a schematic configuration diagram of an “internal combustion engine cooling water flow control device (first device)” and an internal combustion engine to which the cooling water flow control device according to the first embodiment of the present invention is applied. FIG. 2 is a graph for explaining the outline of the operation of the first device. FIG. 3 is a graph for explaining the outline of the operation of the first device. FIG. 4 is a flowchart showing a routine executed by the CPU of the ECU shown in FIG. FIG. 5 is a flowchart showing a routine executed by the CPU of the ECU of the “cooling water flow rate control device for an internal combustion engine (second device)” according to the second embodiment of the present invention.

  Hereinafter, "a cooling water flow rate control device for an internal combustion engine" according to each embodiment of the present invention will be described with reference to the drawings.

<First Embodiment>
(Constitution)
As shown in FIG. 1, the cooling water flow rate control device (hereinafter referred to as “first device”) according to the first embodiment of the present invention is applied to an internal combustion engine 10.

  The internal combustion engine 10 includes a plurality (four in this example) of combustion chambers 12 and cooling water passages 13 in a main body 11 thereof. One end of the cooling water passage 13 constitutes an inlet portion 13 in for allowing cooling water (referred to as “cooling liquid, antifreezing liquid or LLC” in some cases) to flow into the main body 11 from the outside of the main body 11. The other end of the cooling water passage 13 constitutes an outlet portion 13out that allows the cooling water to flow from the inside of the main body 11 to the outside of the main body 11. The cooling water passage 13 extends from the inlet portion 13in to one of the combustion chambers 12, passes through the periphery of the plurality of combustion chambers 12, and then communicates with the outlet portion 13out after passing through the cylinder head portion CL / H. ing.

  The internal combustion engine 10 includes a fuel injection valve 14 for injecting (supplying) fuel into an intake port (not shown) communicating with each combustion chamber 12 in response to an instruction signal from an ECU 60 described later. The ECU is an abbreviation for an electric control unit and is an electronic control circuit having a microcomputer including a CPU, a ROM, a RAM, an interface, and the like as main components. The CPU implements various functions to be described later by executing instructions (routines) stored in a memory (ROM).

The cooling water flow rate control device includes an external circulation passage unit 20.
The external circulation passage portion 20 includes a heater core passage portion 21, an ATF warmer passage portion 22, an engine oil cooler passage portion 23, a pressure loss adjustment passage portion 24, a common passage portion 25, an engine connection passage portion 26, a radiator first passage portion 27, and A radiator second passage portion 28 is included.

  The heater core passage 21 has an upstream end connected to the outlet 13 out of the cooling water passage 13 and a downstream end connected to the common passage 25. The heater core passage 21 has a heater core 31 interposed. The heater core 31 is warmed by heat exchange between the coolant flowing through the heater core passage portion 21 and the heater core 31, and serves as a heat source for a heating device of a vehicle on which the internal combustion engine 11 is mounted. That is, the heater core 31 is an external device that exchanges heat with cooling water. The external device is a heat exchanging section that has a complicatedly bent path and a small flow path area of the path so that heat exchange with the cooling water can be efficiently performed (that is, the heat dissipation / heat receiving area is increased). It is an apparatus provided with.

  The ATF warmer passage 22 has an upstream end connected to the outlet 13out of the cooling water passage 13 and a downstream end connected to the common passage 25. The ATF warmer passage 22 is provided with an ATF warmer 32. The ATF warmer 32 is a device that heats the lubricating oil of the automatic transmission by performing heat exchange between the cooling water flowing through the ATF warmer passage 22 and the lubricating oil of the automatic transmission. That is, the ATF warmer 32 is an external device that performs heat exchange with the cooling water.

  The engine oil cooler passage portion 23 has an upstream end portion connected to the outlet portion 13out of the cooling water passage 13 and a downstream end portion connected to the common passage portion 25. The engine oil cooler passage 23 is provided with an engine oil cooler 33. The engine oil cooler 33 is a device that cools the lubricating oil of the internal combustion engine 10 by exchanging heat between the coolant flowing through the engine oil cooler passage 23 and the lubricating oil of the internal combustion engine 10. That is, the engine oil cooler 33 is an external device that exchanges heat with cooling water.

  The upstream end of the pressure loss adjusting passage 24 is connected to the outlet 13 out of the cooling water passage 13, and the downstream end thereof is connected to the common passage 25. The pressure loss adjusting passage portion 24 does not include an external device that performs heat exchange with the cooling water flowing through the pressure loss adjusting passage portion 24, and directly connects the outlet portion 13out and the common passage portion 25. .

The common passage portion 25 is connected to the first pump inflow portion 41 of the water pump 40.
The engine connection passage portion 26 has an upstream end connected to the discharge portion 43 of the water pump 40 and a downstream end connected to the inlet portion 13 in of the cooling water passage 13.

The upstream first end of the radiator first passage portion 27 is connected to the outlet portion 13out of the cooling water passage 13, and the downstream end portion thereof is connected to the cooling water intake portion 34in of the radiator 34.
The radiator second passage portion 28 has an upstream end connected to the cooling water outlet 34 out of the radiator 34 and a downstream end connected to the second pump inflow portion 42 of the water pump 40. As is well known, the radiator 34 is a device for cooling the cooling water with air. That is, the radiator 34 is an external device that exchanges heat with cooling water.

  The water pump 40 is rotated (driven) by an electric motor (DC motor) (not shown), pressurizes the cooling water introduced through the first pump inflow portion 41 and the second pump inflow portion 42, and discharges the pressurized cooling water. It discharges from the part 43. This electric motor is hereinafter also referred to as “pump motor”. Electric power is supplied to the pump motor from the battery of the vehicle on which the internal combustion engine 10 is mounted.

The cooling water flow rate control device further includes a cooling water control valve device 50.
The cooling water control valve device 50 includes a first control valve 51 to a fifth control valve 55.

  The first control valve 51 is interposed in the heater core passage portion 21 and changes the opening VO1 in accordance with an instruction signal from the ECU 60, thereby changing the passage area (flow passage cross-sectional area) of the heater core passage portion 21. To do. When the water pump 40 is driven and the opening VO1 of the first control valve 51 is greater than “0”, the cooling water passes through the first control valve 51 from the outlet portion 13out and passes through the heater core passage portion 21 and the heater core 31. , It passes through the common passage 25, the water pump 40 and the engine connection passage 26 and reaches the inlet 13in.

  The second control valve 52 is interposed in the ATF warmer passage 22 and changes the opening VO2 in accordance with an instruction signal from the ECU 60, thereby changing the passage area of the ATF warmer passage 22. When the water pump 40 is driven and the opening degree VO2 of the second control valve 52 is larger than “0”, the cooling water passes through the second control valve 52 from the outlet portion 13out and passes through the ATF warmer passage portion 22 and the ATF warmer 32. Through the common passage 25, the water pump 40, and the engine connection passage 26 to reach the inlet 13in.

  The third control valve 53 is interposed in the engine oil cooler passage portion 23 and changes the opening VO3 in accordance with an instruction signal from the ECU 60, thereby changing the passage area of the engine oil cooler passage portion 23. When the water pump 40 is driven and the opening VO3 of the third control valve 53 is larger than “0”, the cooling water passes through the third control valve 53 from the outlet portion 13out and passes through the engine oil cooler passage portion 23 and the engine oil. It passes through the cooler 33, passes through the common passage 25, the water pump 40, and the engine connection passage 26 and reaches the inlet 13in.

  The fourth control valve 54 is interposed in the pressure loss adjusting passage 24, and changes the opening VO4 in accordance with an instruction signal from the ECU 60, thereby changing the passage area of the pressure loss adjusting passage 24. When the water pump 40 is driven and the opening VO4 of the fourth control valve 54 is larger than “0”, the cooling water passes through the fourth control valve 54 from the outlet portion 13out and passes through the pressure loss adjusting passage portion 24. It passes through the common passage 25, the water pump 40, and the engine connection passage 26 and reaches the inlet 13in.

  The fifth control valve 55 is interposed in the radiator first passage portion 27, and changes the opening VO5 in accordance with an instruction signal from the ECU 60, thereby changing the passage area of the radiator first passage portion 27. When the water pump 40 is driven and the opening VO5 of the fifth control valve 55 is larger than “0”, the cooling water passes through the fifth control valve 55 from the outlet portion 13out and passes through the first radiator passage 27 and the radiator 34. And pass through the radiator second passage 28, the water pump 40 and the engine connection passage 26 and reach the inlet 13in.

  Here, each passage portion of the external circulation passage portion 20 (that is, the heater core passage portion 21, the ATF warmer passage portion 22, the engine oil cooler passage portion 23, the pressure loss adjustment passage portion 24, and the radiator first passage portion 27) is cooled. The pressure loss when passing is described.

  The pressure loss adjusting passage 24 is not provided with an “external device that exchanges heat with cooling water”. Further, the flow passage area of the common passage portion 25 is sufficiently large. The heater core passage portion 21, the ATF warmer passage portion 22, the engine oil cooler passage portion 23, the pressure loss adjustment passage portion 24, the radiator first passage portion 27, and the radiator second portion. The flow passage areas of the passage portions 28 are set to be equal to each other. Therefore, when each of the first control valve 51 to the fifth control valve 55 is fully opened, the pressure loss when the cooling water having a specific kinematic viscosity flows through the pressure loss adjusting passage portion 24 is other than The pressure loss when flowing through each of the passage portions (that is, the heater core passage portion 21, the ATF warmer passage portion 22, the engine oil cooler passage portion 23, the pressure loss adjusting passage portion 24, and the radiator first passage portion 27) is much smaller. .

  On the other hand, the ECU 60 is connected to a cooling water temperature sensor 61, an engine rotation speed sensor 62, an air flow sensor 63, a motor current sensor 64, a voltage sensor 65, a motor rotation speed sensor 66, and other sensors 67, and outputs signals from these sensors. It is supposed to receive.

The cooling water temperature sensor 61 is disposed at the outlet portion 13out of the cooling water passage 13 and outputs a signal THW indicating the temperature of the cooling water passing through the outlet portion 13out.
The engine rotation speed sensor 62 generates one pulse signal each time the crankshaft of the internal combustion engine 10 rotates by a certain angle. The ECU 60 acquires the engine rotational speed NE based on the pulse signal generation interval.
The air flow sensor 63 outputs a signal Ga indicating the flow rate (mass flow rate) of air taken into the internal combustion engine 10.

The motor current sensor 64 outputs a signal Im indicating the magnitude of the current supplied to the pump motor that rotates the water pump 40.
The voltage sensor 65 outputs a signal Vm representing a voltage (that is, battery voltage) applied to the pump motor.
The motor rotation speed sensor 66 outputs a signal Nm indicating the rotation speed of the pump motor.

  The other sensors 67 are signals indicating the operating state of the internal combustion engine 10 (for example, accelerator pedal operation amount PA and throttle valve opening TA), and signals indicating the traveling state of the vehicle on which the internal combustion engine 10 is mounted (for example, vehicle speed SPD). And a brake operation amount BA) and other request signals (for example, a vehicle interior heater request (heating request) signal based on a heating switch operated by an occupant), including one or more sensors and / or switches It is out.

(Overview of operation)
Next, an outline of the operation of the first device will be described.
As can be understood from the graph shown in FIG. 2 in which the horizontal axis is the temperature of LLC and the vertical axis is the reciprocal of the heat transfer coefficient, the LLC temperature is in the normal low temperature region (temperatures T2 to T3: T2 is For example, when the temperature is −10 ° C. and T3 is 80 ° C., for example, the heat transfer coefficient of the high-viscosity LLC indicated by the solid curve C1 is moderately smaller than the heat transfer coefficient of the normal LLC indicated by the dashed curve C2. . Therefore, when the internal combustion engine 10 is in a normal warm-up process, the high-viscosity LLC does not excessively cool the internal combustion engine 10, so that the time required for warming up the internal combustion engine 10 can be shortened.

  On the other hand, when the temperature of the LLC is in a very low temperature region (less than the temperature T2), the heat transfer coefficient of the high viscosity LLC is usually much smaller than the heat transfer coefficient of the LLC. Therefore, since the heat generated in the combustion chamber 12 is difficult to be transmitted to the high viscosity LLC, the actual temperature of the wall surface of the combustion chamber 12 and the cooling water temperature THW detected by the cooling water temperature sensor 61 disposed at the outlet portion 13out. The estimated deviation from the temperature of the wall surface of the combustion chamber 12 becomes very large.

  On the other hand, the ECU 60 of the first device determines the fuel injection amount based on the coolant temperature THW detected by the coolant temperature sensor 61. More specifically, the ECU 60 takes into account that the amount of fuel adhering to the wall surface of the combustion chamber 12 increases when the internal combustion engine 10 is in the warm-up process, and so on, and the more the coolant 60 becomes lower, the lower the coolant temperature THW. It is designed to inject fuel. Therefore, when the high viscosity LLC is used as the cooling water, the fuel injection amount becomes excessive in the extremely low temperature region, so the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine 10 becomes excessively small (over rich). ). As a result, there arises a problem that emission and / or fuel consumption deteriorates.

By the way, the Nusselt number Nu, which is a non-dimensional heat transfer coefficient, is expressed by the following equation (1). In the formula (1), Re is the Reynolds number, and Pr is the Prandtl number.

Nu = 0.023 · Re ^0.8 · Pr ^0.4 (1)

The Reynolds number Re is expressed by the following equation (2). In the equation (2), V is a cooling water (LLC) flow rate, P is a value corresponding to the length of the path through which heat is transferred, β is the density of cooling water, and μ is the kinematic viscosity. The product of P and β can be treated as one coefficient (constant).

Re = (V · P · β) / μ (2)

  To maintain the Nusselt number Nu (that is, the heat transfer coefficient) constant from the above equation (1), the Reynolds number Re may be maintained constant, and from the above equation (2), the Reynolds number Re may be maintained constant. It is understood that the flow rate V should be increased as the kinematic viscosity μ increases.

  Therefore, the ECU 60 of the first device detects (estimates) the actual kinematic viscosity μ of the cooling water based on a method described later, and as shown in FIG. 3, the detected kinematic viscosity μ is greater than a predetermined threshold viscosity μth. Is higher, the flow of the cooling water flowing through the cooling water passage 13 is increased as the detected (estimated) kinematic viscosity μ is higher. As a result, as shown by the white arrow in FIG. 2, even when high viscosity LLC is used as cooling water, the heat transfer coefficient of cooling water at extremely low temperatures is substantially increased to It can be close to the heat transfer coefficient of LLC.

  According to this, even when high-viscosity LLC is used as cooling water, the heat transfer coefficient of cooling water at extremely low temperatures is substantially increased, so that the heat generated in the combustion chamber 12 is transferred to the cooling water. It becomes easy to be transmitted. Therefore, the difference between the actual temperature of the wall surface of the combustion chamber 12 and the temperature of the wall surface of the combustion chamber 12 estimated from the cooling water temperature THW detected by the cooling water temperature sensor 61 disposed at the outlet 13out is reduced. As a result, since the fuel injection amount does not become excessive at extremely low temperatures, it is possible to avoid the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine 10 from becoming excessively small.

  Thus, the ECU 60 of the first device increases the flow rate of the cooling water so that the flow rate of the cooling water flowing through the cooling water passage 13 increases as the detected kinematic viscosity μ increases. In this case, the flow rate of the cooling water flowing through the cooling water passage 13 can be increased by increasing the rotational speed of the water pump 40. However, when the kinematic viscosity μ is high, the pressure loss when circulating the cooling water is large, so increasing the rotational speed of the water pump 40 requires large electric power.

  Therefore, the ECU 60 uses the coolant control valve device 50 (first control valve 51 to fifth control valve 55) to provide the external circulation passage 20 (heater core passage 21, ATF warmer passage 22, engine oil cooler passage 23). The pressure loss is reduced by adjusting the amount of the cooling water flowing through each of the pressure loss adjusting passage portion 24 and the radiator first passage portion 27), and thus the cooling water without greatly increasing the rotation speed of the water pump 40. The amount of cooling water flowing through the passage 13 is increased.

  By the way, as described above, the pressure loss when the cooling water flows through the pressure loss adjusting passage portion 24 is that the cooling water is in other passage portions (that is, the heater core passage portion 21, the ATF warmer passage portion 22, the engine oil cooler passage portion. 23 and the first radiator passage portion 27) are much smaller than the pressure loss when flowing through each of them.

  Further, when cooling water flows through the heater core passage 21, the ATF warmer passage 22, and the engine oil cooler passage 23 at extremely low temperatures, external devices (that is, the heater core 31, ATF warmer 32, and Since the engine oil cooler 33) removes heat from the cooling water, the warm-up of the internal combustion engine 10 is delayed. In addition, when the cooling water is caused to flow through the first radiator passage portion 27, the cooling water is cooled in the radiator 34, so that the warm-up of the internal combustion engine 10 is extremely delayed. In other words, at a very low temperature, when the cooling water flows through the pressure loss adjusting passage 24, the heat of the internal combustion engine 10 can be confined in the circulating path of the cooling water. When flowing through a passage portion other than the portion 24, the heat of the internal combustion engine 10 cannot be confined in the circulation path of the cooling water.

  From the above viewpoint, the ECU 60 controls the cooling water control valve device 50 (that is, the first control valve 51 to the fifth control valve 55) at an extremely low temperature, whereby the flow rate of the cooling water flowing through the cooling water passage 13 is controlled. In this case, the cooling water control valve device is configured so that the cooling water flows as much as possible in the pressure loss adjusting passage portion 24 as compared with the other passage portions (except for the heater core passage portion 21 in some cases). 50 is controlled. The above is the outline of the operation of the first device.

(Specific operation)
The CPU of the ECU 60 (hereinafter simply referred to as “CPU”) executes a “cooling water flow rate control routine” shown in a flowchart in FIG. 4 every time a predetermined time elapses. Therefore, when the predetermined timing comes, the CPU starts the process from step 400 of FIG. 4, performs the processes of steps 405 to 430 described below in order, and proceeds to step 435.

  Step 405: The CPU acquires the respective opening degrees (VO1, VO2, VO3, VO4, VO5) of the first control valve 51 to the fifth control valve 55 at that time. Note that immediately after the internal combustion engine 10 is started by changing an ignition key switch (not shown) from the off position to the on position, the opening VO1 of the first control valve 51 is set to a minute first opening. Each of the second control valve 52 to the fifth control valve 55 is maintained in a fully closed state.

  Step 410: The CPU obtains the current Im flowing from the motor current sensor 64 to the pump motor, obtains the voltage Vm applied to the pump motor from the voltage sensor 65, and calculates the product of the current Vm of the pump motor. Obtained as power consumption Pm (Pm = Im · Vm). Note that the CPU sets the current Im in accordance with the voltage Vm so that the rotational speed of the pump motor coincides with the constant target rotational speed N1 until a predetermined time elapses after the internal combustion engine 10 is started. It is adjusted.

  Step 415: The CPU acquires the rotational speed Nm of the pump motor from the motor rotational speed sensor 66.

  Step 420: The CPU estimates the kinematic viscosity μ of the cooling water (LLC) being used. More specifically, the CPU estimates the kinematic viscosity μ by the following steps.

    S1: The CPU calculates the viscosity estimation look-up table Mapμ (Pm, Pm, P) based on the opening degrees (VO1, VO2, VO3, VO4, VO5) of the first control valve 51 to the fifth control valve 55 acquired in step 405. Nm). The table Mapμ (Pm, Nm) indicates the power consumption Pm of the pump motor and the pump for each combination of the opening degrees (VO1, VO2, VO3, VO4, VO5) of the first control valve 51 to the fifth control valve 55. The relationship between the combination of the rotational speed Nm of the motor for use and the kinematic viscosity μ of the cooling water is obtained by experiment, and this is stored in the ROM in a look-up table format.

    S2: The CPU adds the actual power consumption Pm of the pump motor acquired in step 410 to the viscosity estimation table Mapμ (Pm, Nm) selected in S1 and the actual rotation of the pump motor acquired in step 415. By applying the speed Nm, the actual kinematic viscosity μ of the cooling water currently used is detected (estimated).

  Step 425: The CPU determines a required flow rate of cooling water (a flow rate of cooling water required for cooling the internal combustion engine 10) Freq. More specifically, the CPU determines the basic required flow rate Fbse by applying the engine speed NE and the engine load KL to the base look-up table MapFbse (NE, KL), and adds the correction amount α ( μ) is added to determine the required flow rate Freq. The correction amount α (μ) is determined so as to gradually increase from “0” as the kinematic viscosity μ acquired in step 420 increases above the threshold μth, as shown in the block B2 of FIG.

The engine load (load factor) KL is obtained by the following equation (3). In the expression (3), Mc is an intake air amount (in-cylinder intake air amount) that one cylinder sucks in one intake stroke, ρ is an air density (unit is (g / l)), and L is an internal combustion engine. The displacement of the engine 10 (unit: (l)), “4” is the number of cylinders of the internal combustion engine 10. The in-cylinder intake air amount Mc is estimated from the intake air amount Ga, the engine rotational speed NE, and a lookup table. Instead of the load factor KL, the accelerator pedal operation amount Ap may be used as a parameter representing the load of the internal combustion engine 10.

KL = (Mc / (ρ · L / 4)) · 100% (3)

  Step 430: The CPU determines the target rotation speed Nmt of the pump motor by applying the actual engine rotation speed NE and the actual engine load KL to the lookup table MapNmt (NE, KL).

  Next, the CPU proceeds to step 435 to determine whether or not a vehicle interior heater request has occurred.

  When the vehicle interior heater request is generated, it is necessary to satisfy the passenger heating request. Therefore, in this case, the CPU makes a “Yes” determination at step 435 to proceed to step 440, where the opening degree of each control valve (51-55) is based on the required flow rate Freq and the first control valve priority. (VO1, VO2, VO3, VO4, VO5) is determined.

  The first control valve priority is given priority to the first control valve 51 with respect to the heater core passage portion 21 because there is a heating request, and then the pressure loss adjustment passage portion in order to accelerate the warm-up of the internal combustion engine 10. Priority is given to the 4th control valve 54 with respect to 24, Next, it gives priority to the 2nd control valve 52 with respect to the ATF warmer passage part 22 from a viewpoint of fuel consumption, and then gives priority to the 3rd control valve 53 with respect to the engine oil cooler passage part 23 Finally, the order is to prioritize the fifth control valve 55 for the radiator first passage portion 27. Here, “priority” means that the opening degree of the control valve is preferentially increased. The priority order of the second control valve 52 and the priority order of the third control valve 53 may be reversed from the viewpoint of fuel consumption.

  More specifically, the CPU sets the opening degree VO1 of the first control valve 51 to satisfy the required flow rate Freq based on the required flow rate Freq, the target rotational speed Nmt of the pump motor, and the kinematic viscosity μ. It is determined using the lookup table Map1VO1 (Freq, Nmt, μ). When the required flow rate Freq is not satisfied even when the opening degree VO1 of the first control valve 51 is fully opened, the CPU opens the opening degree of the fourth control valve 54 based on the “first control valve priority”. Similarly, VO4 is determined using the lookup table Map1VO4 (Freq, Nmt, μ). Further, if the required flow rate Freq is not satisfied even when both the opening degree VO1 of the first control valve 51 and the opening degree VO4 of the fourth control valve 54 are fully opened, the CPU determines that “the first control valve priority order”. The opening degree VO2 of the second control valve 52 is determined in the same manner. Hereinafter, similarly, the opening degree VO3 of the third control valve 53 and the opening degree VO5 of the fifth control valve 55 are determined. Of course, when the required flow rate Freq is satisfied by opening a control valve having a higher priority, the opening degree of the control valve having a lower priority than the opened control valve is determined to be “0”. Is done.

  Next, the CPU proceeds to step 445 to make the opening (VO1, VO2, VO3, VO4, VO5) of each control valve (51-55) coincide with the opening determined in step 440. Further, the CPU controls the power (actually current) supplied to the pump motor so that the rotational speed Nm of the pump motor matches the target rotational speed Nmt determined in step 430, and the process proceeds to step 495. This routine is finished once.

  On the other hand, if the vehicle interior heater request is not generated when the CPU performs the process of step 435, the CPU makes a “No” determination at step 435 to proceed to step 450, where the requested flow rate Freq and the second flow rate are determined. Based on the control valve priority order, the opening degree (VO1, VO2, VO3, VO4, VO5) of each control valve (51-55) is determined.

  Since there is no heating request, the second control valve priority is given the highest priority on the fourth control valve 54 for the pressure loss adjusting passage 24 instead of the first control valve 51 for the heater core passage 21. From the viewpoint of fuel efficiency, the second control valve 52 for the ATF warmer passage 22 is prioritized, the third control valve 53 for the engine oil cooler passage 23 is prioritized, In this order, the first control valve 51 for the heater core passage portion 21 is given priority, and finally, the fifth control valve 55 for the radiator first passage portion 27 is given priority. Even in this case, the priority order of the second control valve 52 and the priority order of the third control valve 53 may be reversed from the viewpoint of fuel consumption.

  More specifically, the CPU sets the degree of opening VO4 of the fourth control valve 54 to satisfy the required flow rate Freq based on the required flow rate Freq, the target rotational speed Nmt of the pump motor, and the kinematic viscosity μ. It is determined using the lookup table Map2VO4 (Freq, Nmt, μ). When the required flow rate Freq is not satisfied even when the opening VO4 of the fourth control valve 54 is fully opened, the CPU opens the opening of the second control valve 52 based on the “second control valve priority”. Similarly, VO2 is determined using the lookup table Map2VO2 (Freq, Nmt, μ). Further, if the required flow rate Freq is not satisfied even when both the opening degree VO4 of the fourth control valve 54 and the opening degree VO2 of the second control valve 52 are fully opened, the CPU determines that “the second control valve priority order”. The opening degree VO3 of the third control valve 52 is determined in the same manner. Hereinafter, similarly, the opening degree VO1 of the first control valve 51 and the opening degree VO5 of the fifth control valve 55 are determined. Of course, when the required flow rate Freq is satisfied by opening a control valve having a higher priority, the opening degree of the control valve having a lower priority than the opened control valve is determined to be “0”. Is done.

  Thereafter, the CPU executes the process of step 445, proceeds to step 495, and once ends this routine.

  Further, the CPU executes a well-known fuel injection control routine (not shown) to determine the final fuel injection amount TAU as follows, and the fuel of the determined fuel injection amount TAU is supplied to the intake stroke of each cylinder. Injection is performed from the corresponding fuel injection valve 14 immediately before.

The CPU calculates the in-cylinder intake air amount Mc based on the intake air amount Ga, the engine rotational speed NE, and the lookup table.
The CPU calculates a value obtained by dividing the in-cylinder intake air amount Mc by a theoretical air-fuel ratio stoich (for example, 14.6) as the basic fuel injection amount Taub.
The CPU obtains the cooling water temperature THW at the start of the internal combustion engine from the cooling water temperature sensor 61, and calculates a post-start-up increase coefficient Kst (≧ 1) that becomes larger as the cooling water temperature THW at the start is lower. Further, the CPU decreases the post-startup increase coefficient Kst by a predetermined amount every time the internal combustion engine 10 makes one revolution until it becomes “1”.
The CPU acquires the coolant temperature THW from the coolant temperature sensor 61 every elapse of a predetermined time, and calculates a warm-up increase coefficient Kthw (where Kthw ≧ 1) that increases as the acquired coolant temperature THW decreases.
The CPU determines the final fuel injection amount TAU based on the following equation (4).

TAU = Kst / Kthw / Taub (4)

  As described above, the first device reduces the pressure loss when the cooling water passes through the external circulation passage portion 20 according to the kinematic viscosity of the cooling water, while increasing the kinematic viscosity of the cooling water. The flow rate of the cooling water flowing through the cooling water passage 13 in the engine main body is increased. Therefore, heat generated in the combustion chamber 12 of the internal combustion engine is easily transmitted to the cooling water, and the temperature of the combustion chamber wall surface estimated from the actual temperature of the combustion chamber wall surface and the cooling water temperature THW detected by the cooling water temperature sensor 61. The deviation from is reduced. As a result, since the fuel injection amount does not become excessive particularly when the internal combustion engine 10 is at a very low temperature, the “problem that emission and / or fuel consumption deteriorates” can be solved.

  In addition, the first device controls the cooling water control valve device 50 so that the “pressure loss when cooling water flows through the external circulation passage portion 20” decreases as the detected kinematic viscosity increases. Therefore, the flow rate of the cooling water flowing through the cooling water passage 13 can be increased while preventing the energy consumption of the water pump 40 from becoming excessively large.

  Further, the first device is provided with a first circulation passage section including an “external device (32, 33, 34) other than the heater core (31)” that performs heat exchange with the cooling water, and an external device. The second circulation passage portion (24, etc.) and the cooling water has a relatively low kinematic viscosity (while the kinematic viscosity is the first kinematic viscosity). Circulate. Therefore, the heat of the cooling water is hardly released to the outside by the external device, so that the warm-up of the internal combustion engine can be accelerated.

Second Embodiment
The coolant flow rate control device (hereinafter referred to as “second device”) according to the second embodiment of the present invention supplies coolant to the engine oil cooler passage 23 after the warm-up of the internal combustion engine 10 is completed. The third device differs from the first device only in that the third control valve 53 and the fourth control valve 54 at the time of starting passage are different from the first device. Therefore, hereinafter, this difference will be mainly described.

  For example, when high-viscosity LLC is used as the cooling water and the internal combustion engine 10 is started at an extremely low temperature, the fourth flow is performed to increase the flow rate of the cooling water flowing through the cooling water passage 13 according to the detected kinematic viscosity μ. Assume that only the control valve 54 is opened and then the warm-up of the internal combustion engine 10 is completed. At this time, when a request for cooling the lubricating oil of the internal combustion engine 10 using the engine oil cooler 33 is generated, the engine oil cooler passage portion 23 and the engine oil cooler 33 are present when the internal combustion engine 10 is started. The cooling water with a high kinematic viscosity μ remains. Therefore, even if the third control valve 53 is fully opened, the pressure loss of the engine oil cooler passage portion 23 and the engine oil cooler 33 is large and the pressure loss of the pressure loss adjustment passage portion 24 is small. 23 and the engine oil cooler 33 cannot flow sufficiently.

  Therefore, in such a situation, the second device increases the pressure loss of the pressure loss adjusting passage 24 by decreasing the opening VO4 of the fourth control valve 54, and the cooling water is supplied to the engine oil cooler passage 23 and The engine oil cooler 33 is allowed to pass smoothly.

(Specific operation)
The CPU of the ECU 60 of the second device executes a “control valve control routine” shown by a flowchart in FIG. 5 every time a predetermined time elapses. Therefore, when the predetermined timing comes, the CPU starts the process from step 500 in FIG. 5 and proceeds to step 510. At this time, the “request to cool the lubricating oil by the engine oil cooler 33” is present after the current start of the internal combustion engine 10. Determine if it occurred for the first time. If such a request is not made for the first time after the current start of the internal combustion engine 10, the CPU makes a “No” determination at step 510 to directly proceed to step 595 to end the present routine tentatively.

  On the other hand, if such a request is made for the first time after the current start of the internal combustion engine 10, the CPU makes a “Yes” determination at step 510 to proceed to step 520, where the third control valve 53 is set to the current time of the internal combustion engine 10. It is determined whether or not the valve has never been opened after starting. If the third control valve 53 has been opened even once after the current startup of the internal combustion engine 10, the CPU makes a “No” determination at step 520 to directly proceed to step 595 to end the present routine tentatively.

  On the other hand, if the third control valve 53 has never been opened after the current start of the internal combustion engine 10, the CPU makes a “Yes” determination at step 520 to proceed to step 530, where the fourth control valve It is determined whether or not the control valve 54 is opened. If the fourth control valve 54 is not opened, the CPU makes a “No” determination at step 530 to directly proceed to step 595 to end the present routine tentatively.

  On the other hand, when the fourth control valve 54 is opened, the CPU makes a “Yes” determination at step 530, performs the processes of step 540 to step 570 described below in order, and proceeds to step 580.

  Step 540: Immediately after the current startup of the internal combustion engine 10, the CPU reads the kinematic viscosity immediately after startup μs, which is the kinematic viscosity estimated (detected) in step 420 of FIG. Note that the CPU stores the kinematic viscosity μ in the RAM as the kinematic viscosity μs immediately after starting when the kinematic viscosity μ is estimated in step 420 in FIG. 4 immediately after the current starting of the internal combustion engine 10. Note that since the third control valve 53 has never been opened after the current start of the internal combustion engine 10, the cooling water present in the engine oil cooler passage 23 and the engine oil cooler 33 is not in the internal combustion engine 10. There has been no change (not moving) since this start. Therefore, it is considered that the kinematic viscosity of the cooling water existing in the engine oil cooler passage 23 and the engine oil cooler 33 is equal to the kinematic viscosity μs immediately after starting.

  Step 550: The CPU estimates (detects) the current kinematic viscosity μn by performing the same process as the process of Steps 405 to 420 in FIG.

  Step 560: The CPU opens the third control valve 53 by applying the kinematic viscosity μs immediately after starting and the kinematic viscosity μn at the present time to the look-up table MapVO3 (μs, μn) shown in the block B3 of FIG. The degree VO3 is determined. According to the table MapVO3 (μs, μn), the opening degree VO3 is determined so as to increase as the kinematic viscosity μs immediately after the start increases and as the current kinematic viscosity μn decreases.

  This is because when the kinematic viscosity μn at the present time is “a certain viscosity”, the pressure loss of the engine oil cooler passage 23 and the engine oil cooler 33 increases as the kinematic viscosity μs immediately after the start increases. This is because the cooling water easily flows through the engine oil cooler passage portion 23 and the engine oil cooler 33. Further, when the kinematic viscosity μs immediately after starting is “a certain viscosity”, the cooling water is more likely to flow through the pressure loss adjusting passage portion 24 as the current kinematic viscosity μn is smaller. Therefore, the engine oil cooler passage is increased by increasing the opening VO3. This is because the cooling water easily flows through the portion 23 and the engine oil cooler 33.

  Step 570: The CPU opens the fourth control valve 54 by applying the kinematic viscosity μs immediately after start-up and the kinematic viscosity μn at the present time to the look-up table MapVO4 (μs, μn) shown in the block B4 of FIG. The degree VO4 is determined. According to the table MapVO4 (μs, μn), the opening degree VO4 is determined so as to decrease as the kinematic viscosity μs immediately after the start increases and as the current kinematic viscosity μn decreases.

  This is because when the kinematic viscosity μn at the present time is “a certain viscosity”, the pressure loss of the engine oil cooler passage 23 and the engine oil cooler 33 increases as the kinematic viscosity μs immediately after the start increases, so the opening degree VO4 is reduced. This is to make it easier for the cooling water to flow through the engine oil cooler passage portion 23 and the engine oil cooler 33 by making the cooling water difficult to flow through the pressure loss adjusting passage portion 24. Further, when the kinematic viscosity μs immediately after the start is “a certain viscosity”, the cooling water is more likely to flow through the pressure loss adjusting passage 24 as the current kinematic viscosity μn is smaller. Therefore, the pressure loss adjusting passage is reduced by reducing the opening VO4. This is to make it easier for the cooling water to flow through the engine oil cooler passage 23 and the engine oil cooler 33 by making the cooling water difficult to flow through the portion 24.

  Next, the CPU proceeds to step 580 to make the opening VO3 of the third control valve 53 coincide with the opening VO3 determined in step 560, and the opening VO4 of the fourth control valve 54 is determined in step 570. It is made to correspond to opening degree VO4.

  Next, the CPU proceeds to step 590 to determine whether or not the cooling water remaining from the start of the internal combustion engine 10 in the engine oil cooler passage 23 and the engine oil cooler 33 has been removed. More specifically, the CPU determines the rotational speed Nm of the pump motor at that time, the opening degree VO3 of the third control valve 53, the opening degree VO4 of the fourth control valve 54, the kinematic viscosity μs immediately after the start, and the current dynamics. Based on the viscosity μn, the flow rate of the “cooling water flowing through the engine oil cooler passage 23 and the engine oil cooler 33” is estimated. Further, the CPU determines whether or not the integrated value of the flow rate has exceeded the volume of the “engine oil cooler passage portion 23 and engine oil cooler 33” after the start of the processing of step 580, thereby determining the engine oil cooler passage. It is determined whether or not the cooling water remaining in the part 23 and the engine oil cooler 33 from the start of the internal combustion engine 10 has been removed.

  When the CPU determines that the coolant remaining in the engine oil cooler passage 23 and the engine oil cooler 33 from the start of the internal combustion engine 10 has been removed, the CPU proceeds to step 595 to end the present routine tentatively.

  As described above, according to the second device, for example, the engine oil cooler 33 is used after the internal combustion engine 10 in which the high-viscosity LLC is used is started and warmed up when the temperature is extremely low. When the request | requirement to generate | occur | produces, a cooling water can be smoothly circulated through the engine oil cooler 33, and the engine oil cooler 33 can be functioned rapidly.

  The second device is applied when cooling water starts to pass through the engine oil cooler passage 23 after the warm-up of the internal combustion engine 10 is completed, but the control mode of the second device is an ATF warmer passage portion. 22 and the radiator first passage portion 27 can also be applied to the case where cooling water starts to pass.

<High viscosity LLC>
The high viscosity LLC including the first device and the second device and preferably applied to the device according to the embodiment of the present invention is as follows. This high viscosity LLC is described in detail in Patent Document 1 (International Publication No. 2013/183161).

(1) a kinematic viscosity of a 8.5~3000mm ² / s at 25 ° C., and, for an internal combustion engine coolant composition is 0.3 to 1.3 mm ² / s at 100 ° C..
(2) The composition according to (1) above, which contains at least one alcohol selected from the group consisting of dihydric alcohols, trihydric alcohols and glycol monoalkyl ethers and / or water as a base. .
(3) The composition according to the above (1) or (2), comprising a viscosity characteristic improver.
(4) The composition according to (3) above, wherein the viscosity characteristic improver is a phase change material.

<Modification>
The present invention is not limited to the above embodiment, and various modifications can be employed within the scope of the present invention. For example, the cooling water control valve device 50 may be a rotary control valve. In this case, the cross-sectional area of each passage may be changed according to the rotation angle of the valve body of the control valve. Further, the external device may be a device other than the heater core 31, the ATF warmer 32, the engine oil cooler 33, and the radiator 34. Further, step 45 and step 440 in FIG. 4 may be omitted, and the CPU may perform processing in the order of step 430 to step 450 and step 445.

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Main body, 12 ... Combustion chamber, 13 ... Cooling water passage, 13in ... Inlet part, 13out ... Outlet part, 14 ... Fuel injection valve, 20 ... External circulation passage part, 21 ... Heater core passage part, 22 ATF warmer passage, 23 ... Engine oil cooler passage, 24 ... Pressure loss adjustment passage, 25 ... Common passage, 26 ... Engine connection passage, 27 ... Radiator first passage, 28 ... Radiator second passage 31 ... Heater core, 32 ... ATF warmer, 33 ... Engine oil cooler, 34 ... Radiator, 34in ... Cooling water intake part, 34out ... Cooling water take-out part, 40 ... Water pump, 41 ... First pump inflow part, 42 ... First 2 pump inflow part, 43 ... discharge part, 50 ... cooling water control valve device, 51 ... first control valve, 52 ... second control valve, 53 ... third control valve, 54 ... fourth control valve, 55 Fifth control valves, 61 ... cooling water temperature sensor, 62 ... engine rotational speed sensor, 63 ... air flow sensor, 64 ... motor current sensor, 65 ... Voltage sensor, 66 ... motor rotational speed sensor.

Claims (1)

One end portion constitutes an inlet portion to the main body of the cooling water internal combustion engine, and the other end portion is a cooling water passage constituting an outlet portion from the main body of the cooling water internal combustion engine. A cooling water temperature sensor provided with a cooling water passage through which the cooling water for cooling flows in the main body of the internal combustion engine, and the amount of fuel injected and supplied to the internal combustion engine is disposed in the vicinity of the outlet portion. Applied to an internal combustion engine controlled based on the detected temperature of the cooling water;
An external circulation passage portion for connecting the outlet portion and the inlet portion outside the main body of the internal combustion engine to circulate the cooling water;
A water pump that is interposed in the external circulation passage and injects the cooling water from the pump inflow portion and then pressurizes the cooling water and discharges it from the pump discharge portion;
A flow rate controller for changing the flow rate of the cooling water passing through the cooling water passage;
An internal combustion engine cooling water flow rate control device comprising:
The external circulation passage section is
A first circulation passage section that is an external device that performs heat exchange with the cooling water between an outlet portion of the main body of the internal combustion engine and an inflow portion of the water pump, and includes an external device other than the heater core;
The outlet part and the inflow part are directly connected between the outlet part of the main body of the internal combustion engine and the inflow part of the water pump without interposing an external device for exchanging heat with the cooling water. A second circulation passage section,
With
The flow rate controller
A first passage area changing unit that changes a first passage area that is a passage area of the first circulation passage in a range from zero to a first maximum value;
A second passage area changing unit that changes a second passage area that is a passage area of the second circulation passage in a range from zero to a second maximum value;
A kinematic viscosity detector for detecting the kinematic viscosity of the cooling water;
The higher the kinematic viscosity detected, the smaller the pressure loss when the cooling water flows through the external circulation passage portion, and the detected kinematic viscosity is a predetermined first kinematic viscosity. When the second passage area is set to a value larger than zero, the first passage area is set to zero, and the detected kinematic viscosity is a predetermined second kinematic viscosity larger than the first kinematic viscosity. The first passage area changing unit and the second passage area changing unit are set such that the second passage area is set to the second maximum value and the first passage area is set to a value larger than zero. A passage area control unit that increases the flow rate of the cooling water flowing through the cooling water passage in the main body of the internal combustion engine as the detected kinematic viscosity increases.
Cooling water flow rate control device equipped with.

Images