JP2013057290A - Engine cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine cooling device which efficiently meets all demands of a plurality of customers in different periods, thus reducing auxiliary machine loss.SOLUTION: The engine cooling device 1 includes: a main electric water pump 4 connected to a water jacket 2; an auxiliary electric water pump 6 connected to another part of the water jacket 2; and a controller 7 for controlling the operation of the main electric water pump 4 and the auxiliary water pump 6. The controller 7, at the start of the engine, operates only the auxiliary electric water pump 6 to form a start timing circulation path R1, and after the warm-up of the engine, operates the main electric water pump 4 to form a post-warming-up circulation path R2.

Description

  The present invention relates to an engine cooling device in which the demands of a plurality of customers at different timings are all satisfied without waste and the auxiliary machine loss is reduced.

  Of the energy generated by burning fuel in the engine, the energy extracted as the driving force of the vehicle is said to be about 30%. The energy lost without being the driving force of the vehicle includes energy exchanged with the outside air through the cooling water. Thus, it is desired that the energy released to the environment as heat is reduced as much as possible.

  On the other hand, when the temperature of the oil is low, the frictional resistance in the engine or transmission is large and energy is lost. As the oil temperature increases, the frictional resistance decreases, making it difficult to lose energy and improving fuel efficiency. Therefore, it is desirable that the temperature of the oil rises as soon as possible. The energy lost without being the propulsive force of the vehicle described above includes energy for raising the temperature of the oil, but there is a disadvantage that the frictional resistance is reduced by raising the temperature of the oil.

  2. Description of the Related Art Conventionally, in an engine cooling device that cools a vehicle engine, cooling water is circulated to a radiator, an engine water jacket, an oil cooler heat exchanger, an EGR cooler heat exchanger, a heater for heating, and the like. In the conventional engine cooling device, a cooling water channel is laid so as to connect the above-described members, and only one water pump for circulating the cooling water is installed in this cooling water channel.

  There are mechanical and electric water pumps.

  In an engine cooling device using a mechanical water pump, the mechanical water pump is driven by a crankshaft via a transmission mechanism / acceleration / deceleration mechanism such as a belt, a chain, and a gear. When the engine rotation speed increases, the rotation speed of the mechanical water pump increases and the circulation amount of the cooling water increases. When the engine rotation speed decreases, the rotation speed of the mechanical water pump decreases and the circulation amount of the cooling water decreases.

  As a result, in an engine cooling device using a mechanical water pump, the cooling water circulation amount is increased or decreased depending on the engine rotation speed regardless of the cooling water demand amount. The amount of circulation may be larger than that. If the circulation amount is larger than the demand amount, the mechanical water pump is driven wastefully, and so-called auxiliary machine loss increases.

  In an engine cooling device in which a mechanical water pump is used, the mechanical water pump is driven at the same time as the engine is started to start circulation of cooling water. When the engine is cold started, cooling water is circulated throughout the engine water jacket, thus slowing down the engine oil warm-up.

  On the other hand, in an engine cooling device using an electric water pump, the electric water pump is driven by an electronically controlled electric motor, so that the rotation of the electric water pump is controlled asynchronously with the engine rotation.

  As a result, in an engine cooling device using an electric water pump, it is possible to perform control so that the circulating amount of cooling water does not exceed the demand amount even if the engine speed is high, and the electric water pump can be driven wastefully. Absent.

  In an engine cooling device using an electric water pump, it is possible to control the cooling water not to be circulated at the time of cold start, or to control the amount of cooling water to be circulated so that the engine warm-up can be achieved quickly.

  In an engine cooling device using an electric water pump, control with a large circulation amount of cooling water is possible even when the engine speed is low, and heating performance is improved.

  In an engine cooling device using an electric water pump, there is no need for a transmission mechanism / acceleration / deceleration mechanism between the electric motor and the electric water pump, and the auxiliary machine loss due to friction is small.

JP 2010-190050 A JP 2007-205197 A

  However, a conventional engine cooling apparatus using an electric water pump has only one electric water pump.

  At cold start when the outside air temperature is low, control to suppress the circulation of cooling water to the radiator to accelerate engine warm-up and control to promote the circulation of cooling water to the heater for heating to improve heating performance However, these controls are not compatible with only one electric water pump.

  In addition, when the circulation of the cooling water stops in the heat exchanger of the EGR cooler, the cooling water boils and induces a failure of the heat exchanger. Therefore, it is desired to control the electric water pump in which the cooling water is continuously circulated through the heat exchanger of the EGR cooler from the cold start to after the warm-up is achieved.

  As a solution to these problems, a thermostat that switches the path of the cooling water according to the temperature may be provided in the engine cooling device. Thus, when the cooling water temperature is low, the cooling water does not circulate through the radiator. In this engine cooling device, the electric water pump is operated even during cold start, and it becomes possible to improve the heating performance and protect the heat exchanger of the EGR cooler. However, since the energy for circulating the unnecessary cooling water is consumed in the cooling water passage that bypasses the radiator, the warming up of the oil temperature is delayed.

  In particular, since the oil temperature is low at the time of cold start, the frictional resistance inside the engine and the transmission is large and the energy loss is large. Therefore, an early rise in the oil temperature is desired at the cold start. However, when the electric water pump is operated during cold start, the oil temperature is unlikely to rise due to the energy escaping to the cooling water.

  Accordingly, an object of the present invention is to provide an engine cooling apparatus that solves the above-described problems and that satisfies the demands of a plurality of demand destinations with different timings without waste and reduces auxiliary machine losses.

  In order to achieve the above object, an engine cooling device of the present invention is an engine cooling device that circulates cooling water to a water jacket of an engine, a first device, and a second device, and a main electric water connected to the water jacket. A pump, a sub-electric water pump connected to another part of the water jacket, and a control unit that controls the operation of the main electric water pump and the sub-electric water pump. At the time of start-up, only the auxiliary electric water pump is operated and the coolant is circulated through the water jacket and the first device to form a start-up circulation path. By operating an electric water pump and circulating cooling water through the water jacket and the second device, And it forms a machine after circulation path.

  The control unit may stop the auxiliary electric water pump after the engine is warmed up, and form a post-warm-up auxiliary circulation path for supplying cooling water to the first device.

  A cooling water temperature sensor that detects a cooling water temperature in the water jacket is provided, and the control unit determines that the warming-up has not been achieved if the cooling water temperature in the water jacket detected by the cooling water temperature sensor is lower than a threshold, and the threshold If it is above, you may determine with warming-up achievement.

  The control unit cumulatively calculates a fuel injection amount from the start of the engine, determines that warm-up has not been achieved if the fuel injection cumulative amount is less than a threshold value, and determines that warm-up has been achieved if the fuel injection amount is greater than or equal to the threshold value. Good.

  The present invention exhibits the following excellent effects.

  (1) The demands of a plurality of customers at different times are all satisfied without waste.

  (2) Auxiliary machinery loss is reduced.

It is a lineblock diagram of an engine cooling device showing one embodiment of the present invention. It is a systematic diagram of the cooling water channel in the engine cooling device of FIG. It is a figure which shows the circulation of the cooling water at the time of engine starting by this invention. It is a figure which shows the circulation of the cooling water after achievement of warming-up by this invention. It is a systematic diagram of the cooling water channel in the engine cooling device which shows other embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIGS. 1 and 2, an engine cooling device 1 according to the present invention is an engine cooling device that circulates cooling water to a water jacket 2, a first device 5, and a second device 3 of an engine. A main electric water pump 4 connected to the jacket 2, a sub electric water pump 6 connected to another part of the water jacket 2, and a control unit 7 for controlling the operation of the main electric water pump 4 and the sub electric water pump 6. With. In the following, the first device 5 is a heater 5 and the second device 3 is a radiator 3.

  When the engine is started, the control unit 7 operates only the auxiliary electric water pump 6 and circulates the cooling water through the water jacket 2 and the heater 5 to form a starting circulation path R1 (see FIG. 3). After the engine is warmed up, the main electric water pump 4 is operated to circulate the cooling water through the water jacket 2 and the radiator 3, thereby forming a post-warm circulation path R2 (see FIG. 4). It has become. The control unit 7 is configured to stop the auxiliary electric water pump 6 after the engine is warmed up and to form a post-warming auxiliary circulation path R3 (see FIG. 4) for supplying cooling water to the heater 5 for heating. May be.

  In the present embodiment, in the engine cooling device 1, the main electric water pump 4 causes the cooling water to circulate also in the heat exchanger 8 of the oil cooler. In the present embodiment, the engine cooling apparatus 1 is configured such that the auxiliary electric water pump 6 circulates the cooling water also in the heat exchanger 9 of the EGR cooler. Furthermore, in this embodiment, the engine cooling device 1 includes an EGR cooler heat exchanger 9 in series with the heater 5 for heating.

  The auxiliary electric water pump 6 is preferably constituted by a small electric water pump having a smaller maximum capacity (maximum flow rate) and less energy consumption than the main electric water pump 4.

  The control unit 7 is preferably mounted as software in an electronic control unit (ECU).

  As described above, the engine cooling apparatus 1 according to the present invention includes two electric water pumps, and these electric water pumps are individually controlled so that the cooling water is circulated to respective demand destinations. Yes. Under the control of the control unit 7, only the auxiliary electric water pump 6 is operated when the engine is started. Therefore, cooling water is circulated through the heater 5 and the heat exchanger 9 of the EGR cooler, and the heat exchanger of the radiator 3 and the oil cooler. No cooling water is circulated in 8. Thereby, at the time of cold start, circulation of the cooling water to the heater 5 for heating is promoted, so that the heating performance is improved and the circulation of the cooling water to the heat exchanger 9 of the EGR cooler is continued. Thus, boiling of the cooling water is prevented. On the other hand, the circulation of the cooling water to the radiator 3 by the main electric water pump 4 is stopped, so that the engine warm-up is accelerated and the cooling water is circulated to the heat exchanger 8 of the oil cooler by the main electric water pump 4. Is stopped, the oil temperature rises early, the frictional resistance in the engine and transmission (not shown) is reduced, and energy loss is prevented. After the warm-up is achieved, the main electric water pump 4 is operated and the cooling water is circulated through the radiator 3 and the heat exchanger 8 of the oil cooler, so that the cooling water temperature rises excessively or the oil temperature rises excessively. There is nothing to do.

  The description so far includes a mode in which the auxiliary electric water pump 6 is operated even after the warming-up is achieved. However, in the following description, the engine cooling device 1 stops the auxiliary electric water pump 6 after the warming-up is achieved. Cooling water circulation to the heat exchanger 9 of the heater 5 and the EGR cooler is configured to be performed by the main electric water pump 4.

  Specifically, the engine cooling device 1 is connected to a radiator-type cooling water passage 11 extending from the engine water jacket 2 to the water jacket 2 via the radiator 3, and to the water-system cooling water passage 11. The main electric water pump 4 for feeding the water, the first outlet out1, the second outlet out2, the first inlet in1, and the second inlet in2, are connected to the heating heater main outlet hout1 formed in the water jacket 2. One inlet in1 is connected, and the second inlet in2 is connected to the heating heater sub discharge hout2 formed in the water jacket 2, and the first inlet in1 and the first outlet out1 communicate with each other, or the second inlet in2 An upstream switching valve 14a that switches whether the second outlet out2 communicates, and a main that reaches a thermostat 18 to be described later. Between the downstream switching valve 14b installed so as to switch between the branch 12 and the sub-branch 13 formed in the water jacket 2 to the heating heater sub suction port hin, and between the upstream switching valve 14a and the downstream switching valve 14b. The heater 5 is installed, and the auxiliary electric water pump 6 is connected to the second outlet out2 of the upstream switching valve 14a and sends the cooling water to the heater 5.

  Furthermore, when the engine is started, the engine cooling device 1 stops the main electric water pump 4 and operates the auxiliary electric water pump 6 and switches the upstream switching valve 14a and the downstream switching valve 14b to heat the water jacket 2. A start-up circulation path R1 (FIG. 3) is formed from the heater sub-discharge port hout2 via the sub-electric water pump 6 and the heater 5 to the heater heater sub-intake port hin of the water jacket 2 to warm the engine. After the machine has been achieved, the main electric water pump 4 is operated to stop the auxiliary electric water pump 6 and the upstream switching valve 14a and the downstream switching valve 14b are switched, and the warming-up circulation path R2 passing through the radiator cooling water path 11 (FIG. 4) and for heating from the heater main discharge port hout1 of the water jacket 2 Via chromatography data 5 includes a control unit 7 which forms a secondary circulation path after warming up leading to the thermostat 18 R3 (Fig. 4).

  In addition, arrangement | positioning of the member in FIG. 1, and routing of piping do not limit this invention to this.

  The water jacket 2 has a cylinder block portion 15 formed in the cylinder block of the engine, and a cylinder head portion 16 formed in the cylinder head so as to communicate with the cylinder block portion 15 via a narrowed portion gate. The structure of such a water jacket is conventionally known, and when cooling water is introduced into the cylinder block portion 15, the cooling water circulating in the cylinder block portion 15 is discharged from the narrowed portion gate, When cooling water is introduced into the cylinder head portion 16 from the narrowed portion gate, the cooling water circulating in the cylinder head portion 16 is discharged. 1 and 2, the cylinder block portion 15 and the cylinder head portion 16 are shown separately. However, the cylinder block and the cylinder head of the engine are integrated in close contact with each other, and the thickness of the engine The cylinder block portion 15 and the cylinder head portion 16 formed inside are adjacent to each other.

  The cylinder head portion 16 includes a radiator discharge port rout to which the radiator cooling water passage 11 is connected, a heating heater main discharge port hout1, a heating heater sub discharge port hout2, and a heating heater sub suction port hin. It is formed. The cylinder block 15 is formed with a radiator inlet rin to which the radiator cooling water passage 11 is connected. The radiator cooling water passage 11 extends from the radiator outlet rout of the cylinder head portion 16 to the radiator inlet rin of the cylinder block portion 15 via the radiator 3.

  Further, the engine cooling apparatus 1 includes a bypass cooling water channel 17 that branches before the radiator 3 in the radiator cooling water channel 11 and merges with the radiator cooling water channel 11 after the exit of the radiator 3, and the bypass cooling water channel 17 and the radiator system. When the cooling water temperature is lower than the operating temperature, the radiator 3 is cut off and the bypass cooling water channel 17 is opened when the cooling water temperature is lower than the operating temperature. When the cooling water temperature is higher than the operating temperature, the radiator 3 is opened and the bypass cooling water channel 17 is opened. The cylinder head portion 16 from the branching point of the radiator cooling water passage 11 and the bypass cooling water passage 17 from the thermostat 18 to be shut off and the oil cooler discharge outlet oilout formed in the cylinder block portion 15 through the oil cooler heat exchanger 8. And an oil cooler system cooling water channel 19 that joins the side.

  The main electric water pump 4 is installed on the side of the cylinder block 15 from the thermostat 18 of the radiator cooling water channel 11, more specifically, at a location where the radiator cooling water channel 11 is connected to the cylinder block 15, and the main electric water pump 4 Is connected to the radiator inlet rin of the cylinder block 15.

  The internal structure and operating principle of the thermostat 18 are well known and will be briefly described. Of the inlets of the thermostat 18, one of the inlet connected to the bypass cooling water channel 17 and the inlet connected to the radiator 3 is an inlet that is opened to the outlet by the internal valve body and the other is blocked. . The inlet connected to the main branch 12 is an inlet that is always open to the outlet.

  Furthermore, the engine cooling device 1 includes a flow rate control valve 21 at the first outlet out1 of the upstream switching valve 14a, and can control the flow rate of the cooling water when the after-warming sub-circulation path R3 is formed. When the main electric water pump 4 is operated, the control unit 7 controls the flow rate of the cooling water to a predetermined value or less by the flow rate control valve 21.

  In the engine cooling device 1, it is necessary to switch the operation of the electric water pump by determining whether the engine has started and the engine has been warmed up. The engine start can be determined by a conventionally known method such as a start operation performed by a key switch, a cell motor being driven, an engine speed increasing from zero to an idle speed. If this determination includes the cooling water temperature, the oil temperature, the outside air temperature, the elapsed time after the engine is stopped, etc., it is possible to determine the cold start, and it is possible to control the auxiliary electric water pump 6 to be operated only during the cold start. It becomes.

  The determination of the warm-up can be made from the cooling water temperature, the fuel consumption, and the like. That is, the engine cooling device 1 includes a cooling water temperature sensor 22 that detects the cooling water temperature in the water jacket 2. The cooling water temperature sensor 22 is preferably installed in the cylinder block 15. The control unit 7 determines that the warm-up has not been achieved if the coolant temperature in the water jacket 2 detected by the coolant temperature sensor 22 is less than the threshold value, and determines that the warm-up has been achieved if it is equal to or greater than the threshold value. An appropriate value for the threshold is set in advance through experiments. If a temperature limit allowed for the cooling water in the cylinder block 15 is obtained, a threshold lower than the temperature limit is set.

  When it is determined that the warm-up is achieved from the fuel consumption, the control unit 7 cumulatively calculates the fuel injection amount from the start of the engine, and determines that the warm-up is not achieved if the fuel injection cumulative amount is less than the threshold. If it is above, it determines with warming-up achievement. In determining whether the warm-up has been achieved, an oil temperature, an outside air temperature, an elapsed time after starting the engine, or the like may be taken into consideration.

  Below, the control part 7 shall determine with warming-up achievement based on cooling water temperature.

  Next, the operation of the engine cooling device 1 will be described.

  As shown in FIG. 3, when the engine is started, the control unit 7 stops the main electric water pump 4 and operates the auxiliary electric water pump 6 and switches the upstream switching valve 14a and the downstream switching valve 14b to A start-up circulation path R1 from the heating heater sub discharge port hout2 of the jacket 2 to the heating heater sub suction port hin of the water jacket 2 through the sub electric water pump 6 and the heating heater 5 is formed.

  More specifically, since the main electric water pump 4 is stopped, the cooling water does not move in the radiator cooling water passage 11, the bypass cooling water passage 17, the radiator 3, the oil cooler cooling water passage 19, and the cylinder block portion 15. Since the auxiliary electric water pump 6 is operated and the upstream switching valve 14a and the downstream switching valve 14b form a starting circulation path R1, the cooling water in the cylinder head portion 16 is heated by the auxiliary electric water pump 6 to the heater 5 for heating. To be discharged. The cooling water is introduced into the cylinder head portion 16 through the heater 5 and the heat exchanger 9 of the EGR cooler.

  As a result, as shown in FIG. 3, the cooling water is circulated through the path of the auxiliary electric water pump 6 → the heating heater 5 → the heat exchanger 9 of the EGR cooler → the cylinder head portion 16 → the auxiliary electric water pump 6. . As a result, the cooling water is circulated through the heating heater 5 to improve the heating performance, and the cooling water is circulated through the heat exchanger 9 of the EGR cooler to prevent boiling of the cooling water in the heat exchanger 9 of the EGR cooler. Is done. The cooling water circulated at this time is only the cooling water existing in the starting circulation path R1, and is a small amount as compared with the entire cooling water of the engine cooling device 1, and the work required for circulation is small. Therefore, the auxiliary machine loss due to the operation of the auxiliary electric water pump 6 is small.

  On the other hand, in the cylinder block portion 15, the coolant is kept warm without being circulated, so that the engine is warmed up. Further, in the heat exchanger 8 of the oil cooler, since the cooling water is not circulated, the oil temperature rises early, the friction resistance inside the engine and the transmission is reduced, and energy loss is prevented.

  When the engine operation is continued after the engine is started, the coolant temperature of the cylinder block portion 15 rises. If the coolant temperature detected by the coolant temperature sensor 22 is less than the threshold value, the control unit 7 determines that the warm-up has not been achieved, and continues the control at the time of engine start.

  As shown in FIG. 4, if the cooling water temperature is equal to or higher than the threshold value, the control unit 7 determines that the warm-up has been achieved, operates the main electric water pump 4 to stop the auxiliary electric water pump 6 and upstream switching valve. 14a and the downstream switching valve 14b are switched to form a post-warm-up circulation path R2 passing through the radiator cooling water passage 11, and from the heating heater main discharge port hout1 of the water jacket 2 via the heating heater 5. Thus, a secondary circulation path R3 after warming up to the suction port of the main electric water pump 4 is formed.

  More specifically, when the main electric water pump 4 is operated, the cooling water of the radiator cooling water passage 11 is introduced into the cylinder block portion 15. In the cylinder block portion 15, the cooling water circulated inside is discharged to the oil cooler cooling water passage 19 and the cylinder head portion 16. In the cylinder head portion 16, the cooling water circulated inside is discharged to the radiator cooling water passage 11 and the upstream switching valve 14 a is switched to the first outlet out 1, so that the cooling water is supplied from the first outlet out 1. Discharged. The cooling water is sucked into the main electric water pump 4 through the heater 5, the heat exchanger 9 of the EGR cooler, and the thermostat 18. In the radiator cooling water channel 11, the thermostat 18 has not reached the operating temperature, so the radiator 3 is shut off and the cooling water is introduced into the bypass cooling water channel 17.

  As a result, as shown in FIG. 4, the cooling water is supplied from the main electric water pump 4 → the cylinder block portion 15 → the cylinder head portion 16 → the bypass cooling water passage 17 → the thermostat 18 → the radiator cooling water passage 11 → the main electric water pump 4. And the main electric water pump 4 → the cylinder block 15 → the oil cooler cooling water passage 19 → the oil cooler heat exchanger 8 → the bypass cooling water passage 17 → the thermostat 18 → the radiator cooling water passage 11 → the main electric water pump 4 Circulation through the path and main electric water pump 4 → cylinder block portion 15 → cylinder head portion 16 → heating heater 5 → EGR cooler heat exchanger 9 → thermostat 18 → radiator cooling water passage 11 → main electric water pump 4 Is done. As a result, the circulation of the cooling water is maintained in the heating heater 5 and the heat exchanger 9 of the EGR cooler, and the cooling water is also circulated in the heat exchanger 8 of the oil cooler, so that the oil temperature is excessive. Is prevented from rising.

  Thereafter, when the temperature of the cooling water sucked into the main electric water pump 4 from the bypass cooling water channel 17 via the thermostat 18 rises and the thermostat 18 reaches the operating temperature, the bypass cooling water channel 17 is shut off and the cooling water is supplied to the radiator. 3 will be circulated. Thereby, the cooling water is cooled by the radiator 3, and the cooling water temperature is prevented from excessively rising.

  After the warm-up is achieved, the control unit 7 may control the flow rate of the cooling water to a predetermined value or less by the flow rate control valve 21. Thereby, the cooling water more than necessary is not circulated through the heater 5 for heating and the heat exchanger 9 of the EGR cooler, the operation load of the main electric water pump 4 is reduced, and the auxiliary machine loss is reduced.

  3 and 4, the case where it is determined that the warm-up has been achieved based on the coolant temperature has been described, but the switching of the coolant path is the same even when the warm-up is determined from the fuel consumption.

  As described above, in the engine cooling device 1 of the present invention, only the auxiliary electric water pump 6 is operated when the engine is started, so that cooling water is supplied to the heater 5 and the heat exchanger 9 of the EGR cooler. Circulation improves heating performance and prevents boiling of the cooling water in the heat exchanger 9 of the EGR cooler. At the same time, the circulation of the cooling water from the water jacket 2 to the radiator 3 is stopped, so that the engine warm-up is accelerated and the circulation of the cooling water to the heat exchanger 8 of the oil cooler is stopped. As a result, the energy loss due to friction is prevented.

  In the engine cooling device 1 of the present invention, after the warming-up is achieved, the main electric water pump 4 is operated, and the cooling water is circulated through the radiator 3 and the heat exchanger 8 of the oil cooler. The oil temperature will not rise excessively and the oil temperature will not rise excessively. Regardless of whether the engine is started or after warming up, the cooling water is always circulated through the EGR cooler and the heater for which the cooling water needs to be circulated. As described above, in the present invention, the demands of a plurality of customers at different times are all satisfied without waste.

  In the engine cooling device 1 of the present invention, since the amount of cooling water circulated at the time of engine start is small, an electric water pump having a small capacity that is optimal for this amount of cooling water is adopted as the auxiliary electric water pump 6. The main electric water pump 4 employs an electric water pump having a larger capacity than this, but when the engine is started, the main electric water pump 4 is not operated but only the auxiliary electric water pump 6 is operated. Loss is reduced.

  In the present embodiment, the engine cooling device 1 includes the EGR cooler heat exchanger 9 in series with the heater 5. However, as shown in FIG. 5, the engine cooling device 51 according to another embodiment of the present invention. Includes a heat exchanger 9 of an EGR cooler in parallel with the heater 5 for heating. In the engine cooling device 51, the flow rate control valves 23 and 24 are individually provided for the heating heater 5 and the heat exchanger 9 of the EGR cooler, and the flow rates are individually controlled.

DESCRIPTION OF SYMBOLS 1,51 Engine cooling device 2 Water jacket 3 Radiator 4 Main electric water pump 5 Heating heater 6 Sub electric water pump 7 Control part 8 Oil cooler heat exchanger 9 EGR cooler heat exchanger 11 Radiator system cooling water channel 12 Main branch 13 Sub branch 14a Upstream switching valve 14b Downstream switching valve 15 Cylinder block section 16 Cylinder head section 17 Bypass cooling water path 18 Thermostat 19 Oil cooler cooling water path 21, 23, 24 Flow control valve 22 Cooling water temperature sensor R1 Circulation path R2 at start-up Circulation path after machine R3 Sub-circulation path after warm-up

Claims (4)

In the engine cooling device for circulating the cooling water to the engine water jacket, the first device and the second device,
A main electric water pump connected to the water jacket;
A sub-electric water pump connected to another part of the water jacket;
A controller that controls the operation of the main electric water pump and the auxiliary electric water pump;
The controller is
When starting the engine, only the auxiliary electric water pump is operated to circulate the cooling water through the water jacket and the first device, thereby forming a start-up circulation path,
After the engine is warmed up, the main electric water pump is operated to circulate cooling water through the water jacket and the second device, thereby forming a post-warm-up circulation path. Engine cooling device.   The said control part forms the after-warming-up sub circulation path which supplies the cooling water to the said 1st apparatus while stopping the said sub electric water pump after the warming-up of the said engine is achieved. The engine cooling device as described. A cooling water temperature sensor for detecting the cooling water temperature in the water jacket;
The control unit determines that warm-up has not been achieved if the coolant temperature in the water jacket detected by the coolant temperature sensor is less than a threshold value, and determines that warm-up has been achieved if the temperature is equal to or greater than the threshold value. Item 3. The engine cooling apparatus according to Item 1 or 2.   The control unit cumulatively calculates a fuel injection amount from the start of the engine, determines that warm-up has not been achieved if the fuel injection cumulative amount is less than a threshold value, and determines that warm-up has been achieved if the fuel injection amount is greater than the threshold value. The engine cooling apparatus according to claim 1 or 2, wherein the engine cooling apparatus is characterized.