JP2006037883A - Cooling system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for increasing drive efficiency of parts forming a cooling device such as a water pump, an electronic thermostat and an electric fan and for improving fuel consumption. <P>SOLUTION: A plurality of electric water pumps are provided and at least one electric water pump among them is formed to have a different rating from ratings of the other electric water pumps. In the case where the two electric water pumps different in rating are provided, the pump of the smaller rating is driven when a demand circulation flow rate of cooling water required according to operation condition of the internal combustion engine is smaller than a first predetermined rate, when the demand circulation flow rate is larger than the first predetermined rate and smaller than a second predetermined rate, the pump of the larger rating is driven and when the demand circulation rate is larger than the second predetermined rate, the two pumps are driven together. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cooling device for an internal combustion engine, and more particularly to a cooling device that circulates cooling water using an electric water pump.

  As a cooling device for the internal combustion engine, a first water pump that operates by obtaining driving force from the internal combustion engine, and when the cooling water temperature is higher than the predetermined temperature without being driven to rotate when the cooling water temperature is lower than the predetermined temperature, the motor is rotated electrically Proposed by providing a second water pump to drive, ensuring a circulating flow rate of cooling water without increasing the pump head of the first water pump that operates by obtaining driving force from the internal combustion engine, and improving fuel efficiency (For example, refer to Patent Document 1).

  In the cooling apparatus for an internal combustion engine described in Patent Document 1, when the internal combustion engine is started, cooling water having a flow rate proportional to the rotational speed of the internal combustion engine is circulated by the pump action of the first water pump. When the cooling water temperature is lower than a predetermined temperature, such as when cold, the thermostat valve is closed to quickly warm up the internal combustion engine, and the cooling water is not circulated through the radiator. In such a case, the second water pump is not rotationally driven.

And if the cooling water temperature in an internal combustion engine becomes more than predetermined temperature from this state, it is necessary to adjust the temperature of cooling water in order to keep the said cooling water temperature at predetermined temperature. In this case, the valve of the thermostat is opened and the cooling water flows into the radiator, so that the cooling water is cooled. In such a case, since the second water pump is driven when the cooling water temperature is equal to or higher than the predetermined temperature, the circulation flow rate of the cooling water is the sum of the pump head of the first water pump and the pump head of the second water pump. The circulating flow rate of the cooling water in the internal combustion engine and to the radiator is ensured.
JP 2000-179339 A Japanese Patent Laid-Open No. 11-22460 JP 2000-130350 A

  By the way, when the load on the internal combustion engine is small, the temperature of the cooling water in the internal combustion engine may be increased. Therefore, when the load on the internal combustion engine is small, the rotational speed of the pump can be lowered to reduce the circulating flow rate.

  However, in the cooling device for an internal combustion engine described in Patent Document 1 described above, when the cooling water temperature is lower than a predetermined temperature, the cooling water is obtained only by the first water pump that operates by obtaining driving force from the internal combustion engine. Since the first water pump circulates cooling water having a flow rate proportional to the rotational speed of the internal combustion engine, the circulation flow rate cannot be changed according to the load of the internal combustion engine, which is unnecessary. Pump work increases and fuel consumption worsens.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a technique capable of improving the fuel efficiency by increasing the driving efficiency of a water pump that circulates cooling water. is there.

  It is another object of the present invention to provide a technique capable of improving the fuel efficiency by increasing the driving efficiency of the entire components constituting the cooling device such as an electronic thermostat and an electric fan.

  To achieve the above object, a cooling apparatus for an internal combustion engine according to the present invention includes a plurality of electric water pumps and includes at least one electric water pump to include a cooling water passage in the internal combustion engine. A cooling apparatus for an internal combustion engine that circulates cooling water in a cooling water circulation path, wherein a rating of at least one of the plurality of electric water pumps is different from ratings of other electric water pumps. .

  By providing a plurality of water pumps, the size of each water pump can be reduced with respect to a configuration having only one water pump, so that the mountability can be improved. In addition, since the electric water pump has a characteristic that the efficiency increases as the load increases, the efficiency of the electric water pump having a smaller rating than the efficiency of the electric water pump having a higher rating is assumed when the circulation flow rate is the same. Better. Therefore, when the flow rate of cooling water to be circulated is small, only the pump with the lowest rating is driven. When the flow rate cannot be circulated with the pump, only the pump with the next highest rating is driven. By doing so, the pump can be used on the high load side in the entire flow rate region, so that the drive efficiency of the pump can be increased and fuel consumption can be improved. In addition, since the cooling water is circulated by the electric water pump, the flow rate can be arbitrarily controlled, and the warming-up performance is higher than that in which the cooling water is circulated by the water pump that operates by obtaining driving force from the internal combustion engine. Can be improved.

  An internal combustion engine cooling apparatus comprising two electric water pumps having different ratings, and circulating cooling water through a cooling water circulation path including a cooling water passage in the internal combustion engine by driving at least one electric water pump. When the required circulating flow rate, which is the circulating flow rate of cooling water required in accordance with the operating state of the internal combustion engine, is equal to or less than the first predetermined amount, the first electric water having a smaller internal rating of the two electric water pumps A pump is driven, and when the required circulation flow rate is greater than the first predetermined amount and less than or equal to a second predetermined amount, a second electric water pump having a large internal rating of the two electric water pumps is driven, When the required circulation flow rate is greater than the second predetermined amount, a pump drive that drives both the first electric water pump and the second electric water pump. Characterized by comprising a control unit.

  In the cooling apparatus for an internal combustion engine having two electric water pumps with different ratings as described above, the pump drive control means has a required circulation flow rate that is a circulation flow rate of cooling water required according to the operating state of the internal combustion engine. Of the two electric water pumps, the first electric water pump having a smaller internal rating is driven, and the required circulation flow rate is greater than the first predetermined amount and less than the second predetermined amount. By driving the second rated electric water pump with a large rating and controlling the two pumps to drive together when the required circulating flow rate is greater than the second predetermined amount, the pump can be operated on the high load side in the entire flow rate region. Therefore, the driving efficiency of the pump can be increased and the fuel consumption can be improved.

  Also, an electric water pump and an electronic thermostat that controls the flow rate of cooling water between the internal combustion engine and the radiator are provided. By driving the electric water pump, a cooling water circulation path including a cooling water passage in the internal combustion engine is provided. A cooling device for an internal combustion engine that circulates cooling water, wherein a detection value of a water temperature sensor that detects the temperature of the cooling water in the cooling water passage is a target temperature that is determined according to the operating state of the internal combustion engine. Considering the power consumption for circulating the cooling water with the electric water pump and the power consumption for opening the valve of the electronic thermostat, the basic circulation flow rate required for the operating state of the internal combustion engine It is characterized by comprising a correction circulation flow rate for correcting the circulation flow rate and a determining means for determining opening and closing of the valve.

In order to lower the cooling water temperature to the target temperature when the temperature of the cooling water in the cooling water passage (actual cooling water temperature), which is the detection value of the water temperature sensor, is much higher than the target temperature, increase the circulation flow rate. It is necessary to circulate cooling water through the radiator by opening the valve of the electronic thermostat. However, depending on the temperature difference between the actual cooling water temperature and the target temperature, either a method of increasing the circulating flow rate or opening the electronic thermostat valve and circulating the cooling water to the radiator may be adopted. However, when the circulation flow rate is increased, the pump consumes that amount of power, and in order to open the valve of the electronic thermostat, power is consumed to open the valve.

  In the cooling apparatus for an internal combustion engine according to the present invention, when the determining means increases the corrected circulation flow rate when the power consumption is reduced by opening the valve rather than increasing the corrected circulation flow rate. If the power consumption is smaller when the corrected circulation flow rate is increased than when the valve is opened, the valve is closed and the corrected circulation flow rate is increased. In consideration of the power consumption for circulating the cooling water with the electric water pump and the power consumption for opening the valve of the electronic thermostat, the correction circulation flow rate and the opening / closing of the valve are determined. Overall driving efficiency can be increased, and fuel consumption can be improved.

  An internal combustion engine that includes an electric water pump and an electric fan that cools the cooling water in the radiator, and circulates the cooling water in a cooling water circulation path including the cooling water passage and the radiator in the internal combustion engine by driving the electric water pump. The cooling water is cooled by the electric water pump so that the detected value of the water temperature sensor for detecting the temperature of the cooling water in the cooling water passage becomes a target temperature determined according to the operating state of the internal combustion engine. In consideration of the power consumption for circulating the air and the power consumption for driving the electric fan, the corrected circulation flow rate for correcting the basic circulation flow rate that is the circulation flow rate of the cooling water required according to the operating state of the internal combustion engine And determining means for determining whether or not to drive the electric fan.

  When the actual cooling water temperature is much higher than the target temperature, in order to lower the cooling water temperature to the target temperature, it is necessary to increase the circulation flow rate and drive the electric fan to cool the cooling water in the radiator. is there. However, depending on the temperature difference between the actual cooling water temperature and the target temperature, any one of methods of increasing the circulation flow rate or driving the electric fan to cool the cooling water in the radiator may be adopted. However, when the circulation flow rate is increased, the pump consumes that amount of power, and when the electric fan is driven, power is consumed.

  In the cooling apparatus for an internal combustion engine according to the present invention, when the determining means consumes less power when driving the electric fan than increasing the corrected circulation flow rate, the correction circulation flow rate is reduced. If it is determined to drive the electric fan without increasing it, and the power consumption is smaller when the corrected circulation flow rate is increased than when the electric fan is driven, the electric fan is not driven and the electric fan is not driven. The correction circulation flow rate and the electric fan are driven in consideration of the power consumption for circulating the cooling water by the electric water pump and the power consumption for driving the electric fan, such as determining to increase the correction circulation flow rate. Therefore, it is possible to increase the driving efficiency of the entire components of the cooling device and improve the fuel consumption.

An electric water pump; an electronic thermostat that controls a flow rate of cooling water between the internal combustion engine and the radiator; and an electric fan that cools the cooling water in the radiator, and drives the electric water pump. A cooling device for an internal combustion engine that circulates cooling water in a cooling water circulation path including a cooling water passage in the internal combustion engine, wherein a detection value of a water temperature sensor that detects the temperature of the cooling water in the cooling water passage is an internal combustion engine Power consumption for circulating cooling water with the electric water pump, power consumption for opening the valve of the electronic thermostat, and consumption for driving the electric fan so that the target temperature is determined according to the operating state of A corrected circulation flow rate that corrects a basic circulation flow rate that is a circulation flow rate of cooling water required in accordance with the operating state of the internal combustion engine in consideration of electric power. Opening and closing of the valve, characterized by comprising a determining means for determining whether to drive the electric fan.

  In order to lower the temperature of the cooling water to the target temperature when the actual cooling water temperature is much higher than the target temperature, it is necessary to increase the circulation flow rate, open the valve of the electronic thermostat, and drive the electric fan. However, depending on the temperature difference between the actual cooling water temperature and the target temperature, (1) Only the circulation flow rate is increased, (2) The cooling water is circulated through the radiator without increasing the circulation flow rate, and the electric fan is not driven. (3) Any method of circulating the cooling water through the radiator and driving the electric fan without increasing the circulation flow rate may be adopted.

  In the cooling device for an internal combustion engine according to the present invention, when the determining means opens the valve and drives the electric fan to reduce power consumption rather than increasing the corrected circulation flow rate, It is determined that the valve is opened and the electric fan is driven without increasing the correction circulation flow rate, and the power consumption is higher when the correction circulation flow rate is increased than when the valve is opened and the electric fan is driven. If it is smaller, the power consumption for circulating the cooling water with the electric water pump, such as determining to increase the corrected circulation flow without closing the valve and driving the electric fan, the electronic thermostat In consideration of power consumption for opening the valve and power consumption for driving the electric fan, the corrected circulation flow rate, opening and closing of the valve, Because it determines whether to drive the dynamic fan, it is possible to increase the driving efficiency of the overall components of the cooling system, it is possible to improve fuel economy.

  Moreover, the cooling device for an internal combustion engine according to the present invention described above includes two electric water pumps having different ratings, and circulates the cooling water in the cooling water circulation path by driving at least one electric water pump. When the required circulation flow rate, which is the circulation flow rate obtained by adding the corrected circulation flow rate determined by the determining means to the basic circulation flow rate, is equal to or less than a first predetermined amount, the first lower rating of the two electric water pumps An electric water pump is driven, and when the required circulation flow rate is greater than the first predetermined amount and less than or equal to a second predetermined amount, the second electric water pump having a larger internal rating of the two electric water pumps is driven. When the required circulation flow rate is greater than the second predetermined amount, both the first electric water pump and the second electric water pump are driven. It is preferable, further comprising a pump drive control means for.

  In the cooling apparatus for an internal combustion engine having two electric water pumps with different ratings as described above, the pump drive control means sets the corrected circulation flow rate determined by the determination means to the basic circulation flow rate required according to the operating state of the internal combustion engine. When the required circulation flow rate, which is the added circulation flow rate, is equal to or less than the first predetermined amount, the first electric water pump having the smaller internal rating of the two electric water pumps is driven, and the required circulation flow rate is the first predetermined amount. Control is made to drive the second electric water pump having a higher rating when it is greater than or equal to the second predetermined amount, and to drive the two pumps together when the required circulation flow rate is greater than the second predetermined amount. As a result, the pump can be used on the high load side in the entire flow rate region, so that the drive efficiency of the pump can be increased and fuel consumption can be improved.

  As described above, according to the present invention, the driving efficiency of a water pump that circulates cooling water can be increased, and fuel consumption can be improved. In addition, it is possible to improve the fuel efficiency by increasing the driving efficiency of the entire components constituting the cooling device such as the electronic thermostat and the electric fan.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to the drawings, the best mode for carrying out the present invention will be illustratively described in detail based on the following embodiments. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the embodiments are not intended to limit the scope of the present invention only to those unless otherwise specified.

  FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine 1 equipped with a cooling device according to the present embodiment and its cooling water circulation system. The internal combustion engine 1 is a compression ignition internal combustion engine (diesel engine) using light oil as a fuel or a spark ignition internal combustion engine (gasoline engine) using gasoline as a fuel, and is an internal combustion engine mounted on an automobile or the like.

  The internal combustion engine 1 is an in-line four cylinder, and includes a cylinder head 1a, a cylinder block 1b connected to the lower portion thereof, and the like. The cylinder head 1a and the cylinder block 1b are provided with an engine cooling water passage 1c that is a passage for circulating water as a heat medium. As shown in FIG. 1, at the outlet side of the engine coolant passage 1 c, the heater side coolant passage 3 that guides coolant to the heater core 2 for heating the vehicle interior and the radiator side coolant that guides coolant to the radiator 4 are provided. A water passage 5 is connected.

  In addition, the internal combustion engine 1 sucks in the cooling water that has flowed through the heater-side cooling water passage 3 and the radiator-side cooling water passage 5 from the outside. A first electric water pump 6 and a second electric water pump 7 to be fed are provided in parallel. These electric water pumps 6 and 7 are water pumps using a battery (not shown) as a drive source. When a voltage is applied according to a command signal from an ECU, which will be described later, the flow rate is cooled by an amount corresponding to the applied voltage. Water is supplied to the engine cooling water passage 1c. The electric water pumps 6 and 7 have different ratings, and the first electric water pump 6 has a lower rating than the second electric water pump 7.

  A radiator bypass passage 8 for bypassing the radiator 4 is connected to the radiator side cooling water passage 5, and an electronic thermostat 9 is provided at a connection portion between the radiator side cooling water passage 5 and the radiator bypass passage 8. .

  This electronic thermostat 9 controls the flow rate at which the cooling water passing through the radiator 4 and flowing through the radiator side cooling water passage 5 and the cooling water flowing through the radiator bypass passage 8 flow out to the electric water pumps 6 and 7. It has a wax-type thermostat valve. This thermostat valve utilizes a wax that compresses and expands according to temperature, and mechanically opens and closes the valve according to the temperature of the cooling water that has passed through the engine cooling water passage 1c. Specifically, the thermostat valve includes a temperature sensing portion filled with the wax, and the flow area of the radiator side cooling water passage 5 is expanded by expansion of the wax in the temperature sensing portion, Further, the flow passage area of the radiator bypass passage 8 is reduced. When the flow area of the radiator side cooling water passage 5 becomes the maximum, the flow area of the radiator bypass passage 8 becomes zero.

  The electronic thermostat 9 includes a PTC (Positive Temperature Coefficient) heater that electrically heats the temperature sensing unit. Then, by electrically heating the wax by energizing the PTC heater, it is possible to electronically control the opening and closing of the thermostat valve separately from the mechanical opening and closing control.

  Moreover, the electric fan 10 is arrange | positioned corresponding to the radiator 4, and when it supplies with electricity by the command signal of ECU mentioned later, the electric fan 10 will drive and it will become possible to cool the cooling water in the radiator 4. FIG. ing.

The internal combustion engine 1 including the cooling device configured as described above is provided with an electronic control unit (ECU) 11 for controlling the internal combustion engine and the like. This EC
U11 is an arithmetic logic circuit including a CPU, ROM, RAM, backup RAM, and the like.

  The ECU 11 includes a crank position sensor (not shown) that outputs an electrical signal corresponding to the rotational speed of the crankshaft that is the output shaft of the internal combustion engine 1, and an electrical signal that corresponds to the amount of air taken into the cylinder of the internal combustion engine 1. An air flow meter (not shown) that outputs a water temperature sensor 12 that outputs an electric signal corresponding to the temperature of the cooling water flowing through the engine cooling water passage 1c on the cylinder head 1a side is electrically connected. An output signal is input to the ECU 11.

  The ECU 11 executes, for example, input of output signals of various sensors, calculation of the engine speed, calculation of the intake air amount, etc. in a basic routine to be executed at regular intervals. Various signals input by the ECU 11 and various control values obtained by the ECU 11 in the basic routine are temporarily stored in the RAM of the ECU 11.

  The ECU 11 is electrically connected to the electric water pumps 6 and 7, and the ECU 11 controls the electric water pumps 6 and 7 so as to circulate in the cooling water circulation path including the internal cooling water passage 1 c of the internal combustion engine 1. It is possible to control the flow rate of cooling water (hereinafter referred to as “circulation flow rate”). The ECU 11 is electrically connected to the electronic thermostat 9 and the electric fan 10 so that the ECU 11 can control energization to the PTC heater of the electronic thermostat 9 and energization to the electric fan 10.

  In the cooling device for the internal combustion engine configured as described above, the cooling water is supplied to the in-engine cooling water passage 1c so that the cooling water is circulated through the cooling water circulation path by the electric water pump 6 and / or the electric water pump 7 having different ratings. The electric water pumps 6 and 7 at that time are controlled based on electric water pump drive control described below.

  From the standpoints of improving fuel efficiency associated with reduction of friction in each part of the internal combustion engine 1 and improving power performance of the internal combustion engine 1, the temperature of the cooling water in the internal combustion engine 1 must be maintained at a predetermined temperature. In order to maintain, it is necessary to circulate cooling water having a flow rate corresponding to the operating state of the internal combustion engine 1.

  On the other hand, the electric water pumps 6 and 7 have a characteristic that the efficiency increases as the circulation flow rate increases and the load increases. Therefore, if the circulation flow rate is the same within the range of the circulation flow rate in which the low-rated electric water pump 6 can circulate, the efficiency of the electric water pump 6 having a lower rating than the efficiency of the electric water pump 7 having a higher rating. Is better.

  From the above, the ECU 11 first calculates the circulation flow rate (required circulation flow rate) required in accordance with the operating state of the internal combustion engine 1, in other words, the flow rate of the cooling water to be circulated by the electric water pump. As shown, when the calculated required circulation flow rate is equal to or lower than the first predetermined flow rate Vw1, only the electric water pump 6 having a small rating is driven so that the required circulation flow rate is circulated only by the electric water pump 6. . When the calculated required circulation flow rate is greater than the first predetermined flow rate Vw1 and less than or equal to the second predetermined flow rate Vw2, which is a flow rate greater than the first predetermined flow rate Vw1, only the electric water pump 7 having a higher rating is used. The required circulation flow rate is circulated only by the electric water pump 7 driven. Further, when the calculated required circulation flow rate is larger than the second predetermined flow rate Vw2, both the electric water pump 6 having a lower rating and the electric water pump 7 having a higher rating are driven simultaneously, so that both the electric water pump 6 and the electric water pump 7 are driven. To circulate the required circulation flow rate. The first predetermined flow rate Vw1 is a flow rate determined within the range of the circulation flow rate that the low-rated electric water pump 6 can circulate, and the second predetermined flow rate Vw2 is determined by the high-rated electric water pump 7. The flow rate is determined within the range of the circulation flow rate that can be circulated.

  By driving the electric water pumps 6 and 7 in this manner, the electric water pumps 6 and / or 7 can be used in all flow regions as compared with the configuration in which one highly rated electric water pump is provided and the cooling water is circulated. As shown in FIG. 2, the driving efficiency of the electric water pumps 6 and / or 7 is higher than the driving efficiency of the large rated electric water pump in all flow ranges, as shown in FIG. Will be better. In particular, when the circulation flow rate is small, the effect appears remarkably. In addition, since the cost and size of the electric water pump are different depending on the rating, the cost can be reduced and the mountability can be improved as compared with the case where one large rated electric water pump is provided.

  Further, as compared with the configuration including the first water pump that operates by obtaining driving force from the internal combustion engine and the second water pump that is electrically driven to rotate as described in the section of the background art, Since it is not necessary to drive the pumps 6 and 7, warm-up performance can be improved.

  Hereinafter, the electric water pump drive control in the present embodiment will be specifically described with reference to FIG. FIG. 3 is a flowchart showing a control routine of electric water pump drive control. This routine is stored in the ECU 11 in advance, and is executed by the ECU 11 as an interrupt process triggered by elapse of a fixed time or input of a pulse signal from the crank position sensor.

  In this routine, first, in step (hereinafter referred to as “S”) 101, the ECU 11 determines the circulation flow rate (required circulation flow rate) Vwreq required according to the operating state of the internal combustion engine 1, that is, the electric water pump 6 and / or The flow rate Vwreq of the cooling water to be circulated by the electric water pump 7 is calculated. This is calculated by substituting the intake air amount calculated by the ECU 11 on the basis of the detected value of the air flow meter into a map as shown in FIG. 4 prepared in advance and stored in the ROM. When the internal combustion engine 1 is applied to a hybrid system, the engine output of the internal combustion engine 1 calculated based on the detection value by the motor generator is substituted into a map as shown in FIG. 4 that is created in advance and stored in the ROM. Then, the circulation flow rate Vwreq required for the electric water pump 6 and / or 7 may be calculated.

  Thereafter, the process proceeds to S102, and it is determined whether or not the required circulation flow rate Vwreq calculated in S101 is equal to or less than the first predetermined flow rate Vw1 described above. And when affirmation determination is carried out, it progresses to S103, and the electric water pump 6 with a small rating is controlled so that the cooling water of the required circulation flow rate Vwreq is circulated. That is, a voltage necessary for circulating the required circulation flow rate Vwreq is applied to the electric water pump 6. On the other hand, if a negative determination is made in S102, the process proceeds to S104.

  In S104, whether the required circulation flow rate Vwreq calculated in S101 is equal to or lower than the second predetermined flow rate Vw2, that is, whether Vwreq is greater than the first predetermined flow rate Vw1 and equal to or less than the second predetermined flow rate Vw2. Determine. And when affirmation determination is carried out, it progresses to S105, and the electric water pump 7 with a large rating is controlled so that the cooling water of the required circulation flow rate Vwreq is circulated. That is, a voltage required for circulating the required circulation flow rate Vwreq is applied to the electric water pump 7.

On the other hand, when a negative determination is made in S104, that is, when the required circulation flow rate Vwreq calculated in S101 is larger than the second predetermined flow rate Vw2, the process proceeds to S106, and the cooling water of the required circulation flow rate Vwreq is supplied to the electric water pump 6 and the electric water. The electric water pumps 6 and 7 are controlled so as to be circulated by the pump 7. At that time, as described above, since the electric water pumps 6 and 7 have the characteristic that the efficiency is best when the load is rated, either the electric water pump 6 or 7 is driven at the rating, It is preferable to circulate an insufficient flow rate with another electric water pump.

  In the first embodiment, the drive control of the electric water pumps 6 and 7 when the circulation flow rate required according to the operating state of the internal combustion engine 1 is circulated has been described. However, in this embodiment, the electric water pumps 6, 7, These components are controlled in consideration of the drive efficiency of the entire components constituting the cooling device such as the electronic thermostat 9 and the electric fan 10.

  As described in the first embodiment, the flow rate of the cooling water to be circulated is basically determined according to the operating state of the internal combustion engine 1, but in the present embodiment, it is required according to the operating state of the internal combustion engine 1. The circulation flow rate is a basic circulation flow rate Vwreq1, and further the target temperature of the cooling water in the internal combustion engine 1 (target cooling water temperature; THWreq) and the actual cooling water temperature detected by the water temperature sensor 12 (actual cooling water temperature; THWac). The circulation flow rate is corrected according to the temperature difference. That is, the corrected circulation flow rate Vwreq2 is calculated from the temperature difference ΔT (= THWac−THWreq) between the actual cooling water temperature and the target cooling water temperature, and the final required circulation flow rate Vwreq is added to the basic circulation flow rate Vwreq1 and the corrected circulation flow rate Vwreq2 is added. The obtained value is Vwreq1 + Vwreq2.

  By the way, when the actual cooling water temperature THWac is higher than the target cooling water temperature THWreq, in order to set the actual cooling water temperature THWac to the target cooling water temperature THWreq, (1) the circulation flow rate is increased. It is conceivable to decrease the temperature of the cooling water itself as it is, (3) increase the circulating flow rate, and decrease the temperature of the cooling water itself.

  If the actual cooling water temperature THWac is high when the cooling water is not circulated through the radiator 4, the temperature of the cooling water itself decreases if the thermostat valve of the electronic thermostat 9 is opened and the cooling water is circulated through the radiator 4. . Further, when the cooling water is circulated through the radiator 4 and the electric cooling fan 10 is not driven, and the actual cooling water temperature THWac is high, the electric fan 10 is driven to cool the cooling water in the radiator 4. The temperature of the cooling water itself decreases.

  However, to open the thermostat valve of the electronic thermostat 9, it is necessary to energize the PTC heater as described above, and to drive the electric fan 10, it is necessary to energize the electric fan. In order to increase the circulation flow rate, it is necessary to increase the energization amount to the electric water pump.

  In view of this point, in this embodiment, drive control of the component is performed as follows in consideration of the drive efficiency of the entire component.

  As shown in FIG. 5, the corrected circulating flow rate Vwreq2 in the electric water pump and the thermostat of the electronic thermostat 9 according to the temperature difference ΔT (= THWac−THWreq) between the actual cooling water temperature THWac and the target cooling water temperature THWreq as shown in FIG. It is determined whether or not the valve is opened and whether or not the electric fan 10 is driven.

  That is, when the thermostat valve of the electronic thermostat 9 is closed at the present time and the electric fan 10 is not driven, drive control is performed as follows. When ΔT is greater than or equal to zero and smaller than T1, Vwreq2 calculated based on the map of FIG. 5A is set as a corrected circulation flow rate so that the electronic thermostat 9 and the electric fan 10 are not energized. Since ΔT is small, increasing the circulation flow rate without driving the electronic thermostat 9 and the electric fan 10 opens the thermostat valve of the electronic thermostat 9 without increasing the circulation flow rate, and supplies cooling water to the radiator 4. This is because power consumption can be reduced rather than circulating.

  Further, when ΔT is equal to or larger than T1 and smaller than T2, Vwreq2 calculated based on the map of FIG. 5A is used as the corrected circulation flow rate, and the electronic thermostat 9 is energized and the electric fan 10 is not energized. This is because increasing the circulating flow rate by V1 and energizing the electronic thermostat 9 to open the thermostat valve and circulating the cooling water through the radiator 4 increase the circulating flow rate to V1 or more without energizing the electronic thermostat 9. This is because the power consumption can be reduced. When ΔT is smaller than T2, it is considered sufficient to circulate the cooling water through the radiator 4, so it is not necessary to drive the electric fan 10.

  When ΔT is equal to or greater than T2, Vwreq2 calculated based on the map of FIG. 5A is used as the corrected circulation flow rate, and the electronic thermostat 9 and the electric fan 10 are energized. This is because when ΔT is lower than T3, the circulation flow rate is increased by V1, the thermostat valve of the electronic thermostat 9 is opened, the cooling water is circulated through the radiator 4, and the electric fan 10 is driven to cool the cooling water. This is because the power consumption can be reduced compared to increasing the circulation flow rate more than V1 without driving the electric fan 10 and opening the thermostat valve of the electronic thermostat 9 to circulate the cooling water to the radiator 4. is there. However, when ΔT is equal to or greater than T3, the temperature difference is very large. Therefore, the circulating flow rate is increased more than V1, the thermostat valve of the electronic thermostat 9 is opened, the cooling water is circulated to the radiator 4, and the electric motor is electrically operated. It is necessary to drive the fan 10 to cool the cooling water in the radiator 4.

  On the other hand, in the state where the PTC heater of the electronic thermostat 9 is energized to open the thermostat valve and the electric fan 10 is not driven, drive control is performed as follows. That is, when ΔT is greater than or equal to zero and smaller than T4, Vwreq2 calculated based on the map of FIG. 5A is used as the corrected circulation flow rate, and the energization to the electronic thermostat 9 is stopped and the electric fan 10 is not energized. To do. Further, when ΔT is equal to or larger than T4 and smaller than T2, Vwreq2 calculated based on the map of FIG. 5A is set as the corrected circulation flow rate, and the electric thermostat 9 is continuously energized and the electric fan 10 is not energized. To do. When ΔT is equal to or greater than T2, Vwreq2 calculated based on the map of FIG. 5A is used as the corrected circulation flow rate, and energization of the electronic thermostat 9 is continued and the electric fan 10 is also energized.

  In the state where the electronic thermostat 9 is energized to open the thermostat valve and the electric fan 10 is energized to drive the electric fan 10, drive control is performed as follows. That is, when ΔT is greater than or equal to zero and smaller than T4, Vwreq2 calculated based on the map of FIG. 5A is set as the corrected circulation flow rate, and energization to the electronic thermostat 9 and the electric fan 10 is stopped. Further, when ΔT is equal to or larger than T4 and smaller than T5, Vwreq2 calculated based on the map of FIG. 5A is set as the corrected circulation flow rate, the energization to the electronic thermostat 9 is continued, and the energization to the electric fan 10 is stopped. . When ΔT is equal to or greater than T5, Vwreq2 calculated based on the map of FIG. 5A is used as the corrected circulation flow rate, and energization of the electronic thermostat 9 and the electric fan 10 is continued.

  Regardless of whether the electronic thermostat 9 is energized to open the thermostat valve or the electric fan 10 is energized to drive the electric fan 10, ΔT is smaller than zero, that is, the actual cooling water temperature THW. Is lower than the target cooling water temperature THWreq, Vwreq2 is set to zero as shown in the map of FIG. 5A so that the electronic thermostat 9 and the electric fan 10 are not energized.

Note that the values of T1 to T5 and the value of Vwreq2 with respect to ΔT shown in FIG. 5 vary depending on the specifications of the electric water pumps 6 and 7, the electronic thermostat 9, and the electric fan 10, and are previously derived by experiments or the like. It is.

  For example, in FIG. 5A, the value of Vwreq2 is constant V1 in the range of T1 ≦ ΔT ≦ T3, but the value of Vwreq2 / ΔT may be a positive value smaller than V1 / T1.

  After the final required circulation flow rate Vwreq (= wreq1 + Vwreq2) is determined, the electric water pumps 6 and 7 are driven and controlled in the same manner as in the first embodiment.

  Hereinafter, the drive control of the components of the cooling device in the present embodiment will be specifically described with reference to FIG. FIG. 6 is a flowchart showing a control routine for drive control of the component parts. This routine is stored in the ECU 11 in advance, and is executed by the ECU 11 as an interrupt process triggered by elapse of a fixed time or input of a pulse signal from the crank position sensor.

  In this routine, first, in step (hereinafter referred to as “S”) 201, the ECU 11 calculates a basic circulation flow rate Vwreq1 of cooling water to be circulated by the electric water pump 6 and / or the electric water pump 7. As described above, the required circulation flow rate Vwreq in the electric water pump drive control of the first embodiment is set as the basic circulation flow rate Vwreq1, and the processing in S201 is the same processing as S101 in the flowchart of FIG. Detailed description thereof is omitted.

  Thereafter, the process proceeds to S202, where the target coolant temperature THWreq of the internal combustion engine 1 is calculated, and the actual coolant temperature THWac is detected. The target cooling water temperature THWreq is prepared in advance and stored in the ROM in FIG. 7 in which the ECU 11 calculates the intake air amount calculated based on the detected value of the air flow meter and the engine speed calculated based on the detected value of the crank position sensor. It is calculated by substituting into such a map. When the internal combustion engine 1 is applied to a hybrid system, the engine torque calculated based on the shaft torque of the internal combustion engine 1 calculated based on the detection value of the motor generator and the detection value of the crank position sensor is preliminarily calculated. The target cooling water temperature THWreq may be calculated by substituting it into a map as shown in FIG. 7 created and stored in the ROM. The actual cooling water temperature THWac is detected by the water temperature sensor 12.

  Thereafter, the process proceeds to S203, and a temperature difference ΔT between the actual cooling water temperature THWac and the target cooling water temperature THWreq is calculated. This is calculated by substituting the value calculated or detected in S202 into the equation ΔT = THWac−THWreq.

  Thereafter, the process proceeds to S204, and ΔT calculated in S203 is substituted into a map as shown in FIG. 5 created in advance and stored in the ROM to calculate the above-described corrected circulation flow rate Vwreq2, and the electronic thermostat 9 and the electric fan 10 are energized. Decide whether or not to And when it determines with energizing the electronic thermostat 9 and / or the electric fan 10, it will energize.

  Thereafter, the process proceeds to S205, where the final required circulation flow rate Vwreq of the electric water pump is calculated. This is to add Vwreq1 calculated in S201 and Vwreq2 calculated in S204.

  Thereafter, the processing after S206 is executed. Since the processing from S206 to S210 is the same as the processing from S102 to S106 in the flowchart of FIG. 3, detailed description thereof is omitted.

It is a figure showing a schematic structure of an internal-combustion engine provided with a cooling device concerning an embodiment. It is a figure which shows the relationship between the circulation flow rate and efficiency of the electric water pump which concerns on embodiment. 3 is a flowchart illustrating a control routine of electric water pump drive control according to the first embodiment. It is a figure which shows the relationship between the amount of intake air (or engine output) and the request | requirement circulation flow rate Vwreq in Example 1 (or basic circulation flow rate Vwreq1 in Example 2). It is a figure which shows the temperature difference (DELTA) T of actual cooling water temperature and target cooling water temperature, the correction | amendment circulation flow rate Vwreq2, electronic thermostat, and the presence or absence of electricity supply to an electric fan. 6 is a flowchart illustrating a control routine for drive control of components of a cooling device according to a second embodiment. It is a figure which shows the relationship between intake air amount (or engine shaft torque), engine speed, and target water temperature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Heater core 3 Heater side cooling water passage 4 Radiator 5 Radiator side cooling water passage 6, 7 Electric water pump 8 Radiator bypass passage 9 Electronic thermostat 10 Electric fan 11 ECU
12 Water temperature sensor

Claims (9)

A cooling device for an internal combustion engine comprising a plurality of electric water pumps and circulating cooling water through a cooling water circulation path including a cooling water passage in the internal combustion engine by driving at least one electric water pump,
The cooling system for an internal combustion engine, wherein a rating of at least one of the plurality of electric water pumps is different from a rating of another electric water pump. An internal combustion engine cooling device comprising two electric water pumps having different ratings and circulating at least one electric water pump to circulate cooling water in a cooling water circulation path including a cooling water passage in the internal combustion engine,
The first electric water pump having a smaller internal rating of the two electric water pumps when the required circulation flow rate, which is the circulation flow rate of the cooling water required in accordance with the operating state of the internal combustion engine, is equal to or less than the first predetermined amount. When the required circulating flow rate is greater than the first predetermined amount and less than or equal to the second predetermined amount, the second electric water pump having a large internal rating of the two electric water pumps is driven, A cooling apparatus for an internal combustion engine, comprising: pump drive control means for driving both the first electric water pump and the second electric water pump when the required circulation flow rate is larger than the second predetermined amount. . An electric water pump and an electronic thermostat that controls the flow of cooling water between the internal combustion engine and the radiator are provided, and cooling water is supplied to the cooling water circulation path including the cooling water passage in the internal combustion engine by driving the electric water pump. A cooling device for an internal combustion engine that circulates
Power consumption for circulating the cooling water with the electric water pump so that the detected value of the water temperature sensor for detecting the temperature of the cooling water in the cooling water passage becomes a target temperature determined according to the operating state of the internal combustion engine In consideration of the power consumption for opening the valve of the electronic thermostat, the correction circulation flow rate for correcting the basic circulation flow rate, which is the circulation flow rate of the cooling water required according to the operating state of the internal combustion engine, and the opening and closing of the valve A cooling device for an internal combustion engine, comprising a determining means for determining.   The determination means determines that the valve is opened without increasing the corrected circulation flow rate when the power consumption is smaller when the valve is opened than when the correction circulation flow rate is increased. 4. The internal combustion engine according to claim 3, wherein when the power consumption is reduced by increasing the corrected circulation flow rate rather than opening, the valve is closed and the correction circulation flow rate is determined to be increased. Cooling system. Cooling of an internal combustion engine having an electric water pump and an electric fan for cooling the cooling water in the radiator, and circulating the cooling water in a cooling water circulation path including the cooling water passage and the radiator in the internal combustion engine by driving the electric water pump A device,
Power consumption for circulating the cooling water with the electric water pump so that the detected value of the water temperature sensor for detecting the temperature of the cooling water in the cooling water passage becomes a target temperature determined according to the operating state of the internal combustion engine In consideration of the power consumption for driving the electric fan and the electric fan, the correction circulation flow rate for correcting the basic circulation flow rate, which is the circulation flow rate of the cooling water required according to the operating state of the internal combustion engine, and the electric fan are driven. A cooling device for an internal combustion engine, characterized by comprising a determining means for determining whether or not.   The determining means determines to drive the electric fan without increasing the corrected circulation flow rate when power consumption is smaller when driving the electric fan than to increase the correction circulation flow rate. When the power consumption is smaller when the corrected circulation flow rate is increased than when the electric fan is driven, the correction circulation flow rate is determined to be increased without driving the electric fan. The cooling device for an internal combustion engine according to claim 5. An electric water pump, an electronic thermostat that controls the flow rate of cooling water between the internal combustion engine and the radiator, and an electric fan that cools the cooling water in the radiator, and driving the electric water pump A cooling device for an internal combustion engine for circulating cooling water in a cooling water circulation path including a cooling water passage in the internal combustion engine,
Power consumption for circulating the cooling water with the electric water pump so that the detected value of the water temperature sensor for detecting the temperature of the cooling water in the cooling water passage becomes a target temperature determined according to the operating state of the internal combustion engine In consideration of the power consumption for opening the valve of the electronic thermostat and the power consumption for driving the electric fan, the basic circulation flow rate that is the circulation flow rate of the cooling water required according to the operating state of the internal combustion engine is set. A cooling apparatus for an internal combustion engine, comprising: a correction circulation flow rate to be corrected; opening and closing of the valve; and a determination means for determining whether or not to drive the electric fan.   The determining means opens the valve without increasing the corrected circulation flow rate when power consumption is smaller when the valve is opened and the electric fan is driven than when the correction circulation flow rate is increased. If it is determined to drive the electric fan, and the power consumption is smaller when the corrected circulation flow rate is increased than when the valve is opened and the electric fan is driven, the valve is closed and the electric fan is driven. 8. The cooling apparatus for an internal combustion engine according to claim 7, wherein the correction circulation flow rate is determined to be increased without driving a fan. Two electric water pumps having different ratings are provided, and at least one electric water pump is driven to circulate the cooling water in the cooling water circulation path.
When the required circulating flow rate, which is the circulating flow rate obtained by adding the corrected circulating flow rate determined by the determining means to the basic circulating flow rate, is equal to or less than a first predetermined amount, the first electric motor having a small internal rating of the two electric water pumps When the required circulating flow rate is greater than the first predetermined amount and less than or equal to the second predetermined amount, the second electric water pump having a larger internal rating of the two electric water pumps is driven. The apparatus further comprises pump drive control means for driving both the first electric water pump and the second electric water pump when the required circulation flow rate is larger than the second predetermined amount. The cooling device for an internal combustion engine according to any one of 3 to 8.

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