JP2008185021A - Cooling system for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling system for a vehicle enabling appropriate cooling of engine coolant while saving power. <P>SOLUTION: An engine ECU sets rotation speed Rh of an electric pump when engine coolant of a flow rate required for cooling engine coolant is circulated based on the temperature of the engine coolant and the ambient temperature To. When the ambient temperature is high, rotation speed is set higher as compared with the time when the ambient temperature is low. The engine ECU drives the electric pump to secure set rotation speed. Consequently, engine coolant can be appropriately cooled when the ambient temperature is high while rotation speed is prevented from unnecessarily getting high when the ambient temperature is low. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drive control method for an electric pump that circulates engine coolant and a vehicle cooling device that circulates engine coolant.

  In a vehicle equipped with an engine as a driving source for traveling, engine coolant is circulated between the engine and the engine radiator to suppress an increase in engine temperature. Further, an engine coolant is circulated between a heater core of an air conditioner (hereinafter referred to as an air conditioner) provided in a vehicle and an engine, and the heat of the engine coolant is used to generate conditioned air during heating.

  In recent years, hybrid vehicles equipped with electric motors in addition to engines have become widespread as driving sources for traveling. In a hybrid vehicle, when the engine is stopped, the circulation of the engine coolant is also stopped and the heating capacity of the air conditioner is reduced. Therefore, an electric pump is used for the circulation of the engine coolant.

  Incidentally, the electric pump is generally driven at a rotational speed corresponding to the rotational speed of the engine, and when the engine rotational speed is increased, the circulation amount of the engine coolant is increased. When the coolant temperature becomes higher than the set temperature, the coolant temperature is maintained at the set temperature by performing feedback control of the electric pump.

  Moreover, in patent document 2, control of the water temperature of a cooling water is controlled, suppressing electric power consumption by controlling the rotation speed of an electric pump and the opening degree of an electric thermostat based on the water temperature of a cooling water using an electric thermostat. Propose to do.

  On the other hand, the cooling water circulation to the engine radiator and the cooling water circulation to the heater core are performed by the same electric pump, and the electric pump is simply driven in consideration of engine cooling and warm-up. If controlled, there will be insufficient heating capacity of the air conditioner and a delay in starting up the heating.

From this, in Patent Document 3, when the air conditioner is started up, the electric pump is stopped until the water temperature of the cooling water reaches the heater core inlet air temperature, and when the water temperature exceeds the heater core inlet air temperature, The driving of the electric pump is started so that the flow rate can be obtained, and then the electric pump is driven so as to reduce the flow rate of the cooling water as the heater core outlet air temperature approaches the target temperature (for example, the target blowing temperature). Proposes so.
Japanese Patent Laid-Open No. 05-231149 JP 2001-32714 A JP 2004-360509 A

  However, the cooling efficiency of the engine coolant affects not only the circulation amount of the engine coolant to the engine radiator but also the outside air temperature. For this reason, if the electric pump is controlled based on the coolant temperature or the heating capacity of the air conditioner, the circulation amount of the engine coolant may be increased unnecessarily.

  The present invention has been made in view of the above-described facts, and an object of the present invention is to provide a vehicular cooling device that enables proper cooling of engine coolant while saving power.

  In order to achieve the above object, the present invention provides a coolant circuit that enables circulation of engine coolant between an engine and an engine radiator, and the engine coolant between the engine and a heater core of a vehicle air conditioner. A circulation circuit that enables circulation, an electric pump that circulates the engine coolant according to the rotational speed by being driven to rotate to the coolant circuit and the circulation circuit, and an outside air temperature detection unit that detects outside air temperature, When controlling the rotational drive of the electric pump, the electric pump rotates so that the flow rate of the engine coolant circulated through the coolant circuit increases as the outside air temperature detected by the outside air temperature detecting means increases. And control means for increasing the number.

  According to the present invention, by rotating the electric pump, the engine coolant is caused to flow to the engine radiator and the heater core to cool the engine coolant or to perform air conditioning (heating) using the engine coolant.

  At this time, the control means drives the electric pump so that the flow rate of the engine coolant circulated to the engine radiator increases as the outside air temperature detected by the outside air temperature detecting means increases.

  The cooling efficiency of the engine radiator affects the outside air temperature. When the outside air temperature is low, the cooling efficiency increases, and as the outside air temperature increases, the cooling efficiency decreases.

  From here, when the outside air temperature is higher than when the outside air temperature is low, the rotational speed of the electric pump is controlled so that the circulation amount of the engine coolant increases.

  As a result, while preventing the engine coolant from being insufficiently cooled when the outside air temperature is high, it is possible to save power by suppressing the number of rotations of the electric pump from being unnecessarily high when the outside air temperature is low. Can do.

  According to a second aspect of the present invention, the vehicle air conditioner includes a first setting unit that sets the flow rate of the engine coolant in the circulation circuit according to a heating load, and the outside air temperature. Second setting means for setting the flow rate of the engine coolant in the coolant circuit, and the control means obtains the flow rate set by the first and second setting means. An electric pump is driven.

  According to this invention, the engine coolant having the flow rate set by the first setting means is circulated in the circulation circuit, and the engine coolant having the flow rate set by the second setting means is circulated in the coolant circuit. Thus, the operation of the electric pump is controlled. That is, the electric pump is driven so that the flow rate set by the first setting unit and the flow rate set by the second setting unit are ensured.

  At this time, the second setting means sets the flow rate of the engine coolant based on the traveling environment of the vehicle including the outside air temperature.

  Thereby, it is possible to prevent the shortage of the heating capacity in the vehicle air conditioner and the shortage of the cooling capacity of the engine coolant in the engine radiator.

  Furthermore, in the invention according to claim 3, when the engine coolant is circulated at a preset ratio between the coolant circuit and the circulation circuit by driving the electric pump, the first and the first The second setting means sets the rotation speed of the electric pump based on the flow rate, and the control means sets the rotation speed set by the first setting means or the rotation speed set by the second setting means. The electric pump is driven based on any one of the higher rotation speeds.

  According to this invention, the rotational speed of the electric pump based on the higher rotational speed of the rotational speed of the electric pump set by the first setting means and the rotational speed of the electric pump set by the second setting means. To control.

  As a result, when the engine coolant is circulated to each of the coolant circuit and the circulation circuit with one electric pump, the cooling of the engine coolant or the engine coolant can be performed without unnecessarily increasing the rotational speed of the electric pump. The used air conditioning becomes possible.

  As described above, according to the present invention, it is ensured that the coolant is insufficiently cooled when the outside air temperature is high while suppressing the electric pump from being unnecessarily driven when the outside air temperature is low. An excellent effect that it can be prevented is obtained.

  Moreover, in this invention, the heating capability of a vehicle air conditioner can be ensured, ensuring the coolability of engine coolant.

  Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
FIG. 2 shows a schematic configuration of a vehicle air conditioner (hereinafter referred to as an air conditioner 10) applied as a vehicle heating device to the present embodiment. In the air conditioner 10, a compressor 12, a condenser 14, an expansion valve 16, and an evaporator 18 form a refrigeration cycle that circulates refrigerant. In this refrigeration cycle, the compressor 12 is driven to rotate, whereby the refrigerant is compressed and high-temperature and high-pressure refrigerant is sent to the condenser 14.

  The refrigerant is liquefied by being cooled by the condenser 14 and sent to the evaporator 18, and is vaporized by the evaporator 18, thereby cooling the air passing through the evaporator 18. At this time, the moisture in the air is dehumidified by condensation.

  The expansion valve 16 abruptly depressurizes the liquefied refrigerant and sends it to the evaporator 18 as a mist so that the vaporization efficiency of the refrigerant in the evaporator 18 can be improved.

  The air conditioner 10 includes an air conditioner unit 20 in which an evaporator 18 is disposed. In the air conditioner unit 20, an air inlet 22 and an air outlet 24 are formed, and a flow path of air (air conditioned air) is formed from the air inlet 22 toward the air outlet 24, and an evaporator is formed in the flow path. 18 is arranged.

  The air conditioner unit 20 is provided with an inside air introduction port 22A opened as an air introduction port 22 in the vehicle interior and an outside air introduction port 22B opened toward the outside of the vehicle. The air conditioner unit 20 is also provided with a blower fan 26 and a switching damper 28 that selectively opens and closes the inside air introduction port 22A and the outside air introduction port 22B.

  In the air conditioner 10, as an air introduction mode, an inside air circulation mode for introducing air inside the vehicle interior and an outside air introduction mode for introducing air outside the vehicle are set, and the switching damper 28 is operated according to the introduction mode, and the inside air is set. The introduction port 22A or the outside air introduction port 22B is opened, and the blower fan 26 is rotationally driven, whereby the inside air or the outside air is sucked into the air conditioner unit 20 and sent to the evaporator 18.

  Further, in the air conditioner 10, as the air outlet 24, a defroster outlet 24A that opens toward the windshield glass of the vehicle, a register outlet 24B that opens toward the passenger in the passenger compartment, and the feet of the passenger An open foot outlet 24C is formed, and a mode switching damper 30 for selectively opening and closing the defroster outlet 24A, the register outlet 24B, and the foot outlet 24C is provided.

  In the air conditioner 10, in addition to the DEF mode that blows air-conditioned air from the defroster outlet 24A, the FACE mode that blows air-conditioned air from the register outlet 24B, and the FOOT mode that blows air-conditioned air from the foot outlet 24C, A DEF / FOOT mode for blowing the conditioned air from the outlet 24A and the foot outlet 24C, and a BI-LEVEL mode for blowing the conditioned air from the register outlet 24B and the foot outlet 24C are set. In the air conditioner 10, the mode switching damper 30 is operated according to the set blowing mode by setting the blowing mode.

  In the air conditioner unit 20, a heater core 32 that heats air and an air mix damper 34 that controls the amount of air to be heated are provided. In the air conditioner 10, air that has passed through the heater core 32 and air that has bypassed the heater core 32 is provided. The conditioned air generated by mixing is blown out from the air outlet 24. At this time, in the air conditioner 10, the air mix damper 34 controls the amount of air that passes through the heater core 32 and the amount of air that bypasses the heater core 32, thereby generating conditioned air at a predetermined temperature (target blowing temperature). .

  On the other hand, as shown in FIG. 1, the vehicle provided with the air conditioner 10 includes an engine 36 as a driving source for traveling. The engine 36 is a water-cooled internal combustion engine having a general configuration in which a water jacket serving as a circulation path for engine coolant (for example, water, hereinafter referred to as engine coolant) is formed in a cylinder block and a cylinder head (not shown). ing.

  Further, the vehicle is provided with a cooling device 38 for cooling the engine cooling water. The cooling device 38 includes an engine radiator 40, and a cooling water circuit 42 in which cooling water is circulated between the engine 36 and the engine radiator 40 is formed.

  In the cooling water circuit 42, the engine 36 and the engine radiator 40 are connected by cooling water pipes 44A and 44B. The cooling water circuit 42 is provided with a thermostat 46 and a water pump 48.

  In the present embodiment, the thermostat 46 is provided in the cooling water pipe 44A and the water pump 48 is provided in the other cooling water pipe 44B. However, the arrangement of the thermostat 46 and the water pump 48 is not limited to this. For example, it can be set as arbitrary arrangement | positioning, such as providing the thermostat 46 and the water pump 48 in one of the cooling water pipes 44A and 44B.

  The water pump 48 is an electric pump that is rotationally driven by the electric motor 50 (hereinafter, the water pump 48 and the electric motor 50 are collectively referred to as an electric pump 52). In the cooling water circuit 42, the engine cooling water having a flow rate corresponding to the rotational speed R of the electric pump 52 is circulated by the operation of the electric pump 52.

  In the engine radiator 40, heat is exchanged between the air and the engine coolant by introducing air in front of the vehicle. In the cooling device 38, the engine coolant is circulated in the engine 36, so that the temperature rise of the engine 36 is suppressed.

  In the engine radiator 40, air in front of the vehicle is introduced as cooling air according to the traveling speed (vehicle speed) and the like as the vehicle travels. Further, the cooling device 38 is provided with an electric cooling fan 54 facing the engine radiator 40, and the operation of the cooling fan 54 improves the amount of air flow of cooling air to the engine radiator 40, thereby cooling the engine. The water cooling efficiency is improved.

The thermostat 46 is fully opened when the temperature of the cooling water (hereinafter referred to as the water temperature Tw) exceeds a preset temperature (for example, the set temperature T _S1 = 88 ° C.), but the water temperature is the set temperature. When lower than T _S1, gradually narrowing the flow path of the cooling water to the engine radiator 40, the water temperature is lower than the set temperature T _S1 temperature (e.g., the set temperature T _{S2 =} 82 ° C) becomes reaches the fully closed state .

Thereby, the cooling device 38 has a general configuration in which the water temperature of the cooling water is maintained at the target temperature Two (e.g., Two = 90 ° C. to 92 ° C.) higher than the set temperature T _S1 . A thermostat 46 and the other cooling water pipe 44B are connected to the cooling water circuit 42 by a bypass 56, and the thermostat 46 restricts the flow rate of the engine cooling water to the engine radiator 40 so that the cooling water is supplied. It flows through the bypass 56 and is circulated.

  On the other hand, in the air conditioner 10, for example, air-conditioning air having a predetermined temperature is generated by heating air passing through the heater core 32 using engine coolant during heating operation. Between the heater core 32 and the engine 36, a circulation circuit 58 for circulating engine cooling water is formed.

  In this circulation circuit 58, the engine cooling water sent out from the engine 36 by the electric pump 52 being driven to rotate passes through the heater core 32 and is returned to the engine 36 through the electric pump 52. In the heater core 32, heat exchange is performed between the engine coolant and air, and the air passing through the heater core 32 is heated.

  On the other hand, the air conditioner 10 includes an air conditioner ECU 60 that controls the air conditioning operation of the air conditioner 10. The air conditioner ECU 60 has a general configuration including a microcomputer in which a CPU, a ROM, a RAM, and the like are connected to a bus, an input / output interface, various drive circuits (all not shown), and the like.

  In the air conditioner 10, a compressor motor 62 that drives the compressor 12, a blower motor 64 that drives the blower fan 26, a switching damper 28, a mode switching damper 30, and actuators 66A, 66B, and 66C that drive the air mix damper 34 are connected to the air conditioner ECU 60. ing.

  The air conditioner ECU 60 also includes a room temperature sensor 68 that detects the temperature in the vehicle interior, an outside air temperature sensor 70 that detects the outside air temperature, a solar radiation sensor 72 that detects the amount of solar radiation, and the temperature of the air that has passed through the evaporator 18 (post-evaporator temperature). A post-evaporator temperature sensor 74 for detecting the temperature of the engine, a water temperature sensor 76 for detecting the temperature Tw of the engine cooling water circulated through the heater core 32, and the like are connected.

  In the air conditioner ECU 60, when an operating condition is set by operating a switch on an operation panel (not shown) and an air conditioning operation is instructed, an environmental condition or the like is detected by various sensors. Further, the air conditioner ECU 60 performs drive control of the compressor 12 and drive control of the blower fan 26 based on operating conditions, environmental conditions, and the like, as well as switching of the introduction mode, switching of the blowing mode, and opening control of the air mix damper 34. The vehicle interior is set to a set air conditioning state.

For example, air conditioning ECU60, based on the set temperature _{T SET,} and calculates a target supply air temperature _{T AO} for the set temperature _{T SET} the passenger compartment, on the basis of the target outlet air temperature _{T AO,} conditioned air to be blown into the passenger compartment Air volume (blower air volume Va) and the opening S of the air mix damper 34 are set. As a result, the conditioned air at the target outlet temperature TAO is blown out from the air outlet 24 so that the passenger compartment is air-conditioned.

The target blowout temperature T _{AO at} this time is obtained from the set temperature T _SET , the outside air temperature To, the room temperature Tr, and the solar radiation amount ST using a general arithmetic expression.

T _AO = K ₁・ T _SET −K ₂・ To−K ₃・ Tr−K ₄・ ST + C
(K ₁ , K ₂ , K ₃ , K ₄ and C are preset constants)
Meanwhile, blower air volume Va can be set on the basis of the target outlet air temperature T _AO. As shown in FIG. 3, the blower air volume Va is set in a range between a minimum air volume Vamin and a maximum air volume Vamax.

At this time, the air conditioner ECU 60 increases the blower air volume Va when the heating load is large, that is, when the target blowing temperature _TAO is large and when the cooling load is large, that is, when the target blowing temperature _TAO is small. When the heating load or the cooling load is in an intermediate region and the target blowing temperature _TAO is intermediate, the blower air volume Va is reduced.

Further, the air-conditioner ECU 60, controls the opening S of the target outlet air temperature _T air mix as conditioned air to obtain the _AO damper 34. The opening degree S of the air mix damper 34 is obtained from the mixing ratio r, where the ratio of the air volume that has passed through the heater core 32 to the total air volume that has passed through the evaporator 18 is the mixing ratio r.

Here, the mixing ratio r is determined from the temperature of the air that has passed through the evaporator 18 (post-evaporator temperature Te) and the temperature of the air that has passed through the heater core 32 (post-heater core temperature Th).
_{r = (T AO -Te) /} (Th-Te)
It can be.

  At this time, the post-evaporator temperature Te can be detected by the post-evaporator temperature sensor 74, and the post-evaporator temperature Th may be detected by providing a temperature sensor downstream of the heater core 32, or engine cooling water Water temperature Tw, the flow rate of cooling water, and the temperature efficiency η determined for each heater core 32.

  When the air-conditioner ECU 60 calculates the mixing ratio r, the opening degree S of the air mix damper 34 is calculated based on the mixing ratio r, and the actuator 66C is driven so as to obtain the calculated opening degree S. A known general configuration can be applied to the basic air conditioning operation control of the air conditioner 10.

  Incidentally, an engine ECU 78 that controls driving of the engine 36 is provided in a vehicle provided with the air conditioner 10. The engine ECU 78 has a general configuration including a microcomputer, an input / output interface, and various drive circuits (all not shown), and a known configuration is applied to drive control of the engine 36 by the engine ECU 78. be able to.

  In the cooling device 38 according to the present embodiment, this engine ECU 78 is used as a control means. The engine ECU 78 includes a drive circuit for driving the electric pump 52 (electric motor 50) and a fan motor 80 for the cooling fan 54. A drive circuit for driving is provided (all not shown). Further, the engine ECU 78 is connected to a water temperature sensor 82 that detects a water temperature Tw of the engine cooling water.

  In the present embodiment, the water temperature sensor 76 is provided in the air conditioner ECU 60 and the water temperature sensor 82 is provided in the engine ECU 78, but either one of the water temperature sensors may be omitted. For example, the water temperature sensor 76 provided in the air conditioner ECU 60 may be omitted, and the air conditioner ECU 60 may acquire the water temperature Tw detected by the water temperature sensor 82 from the engine ECU 78.

  The engine ECU 78 controls the cooling capacity of the engine coolant in the engine radiator 40 by controlling the rotational speed when the fan motor 80 is driven as well as driving / stopping the fan motor 80.

  Further, the engine ECU 78 controls the flow rate of the engine coolant by controlling the rotational speed of the electric pump 52 along with the operation / stop of the electric pump 52. As the control means of the cooling device 38, the air conditioner ECU 60 may be used, or a control means may be provided separately from the air conditioner ECU 60 and the engine ECU 78. In addition, the rotational speed control of the electric motor 50 and the fan motor 80 is performed by, for example, turning on and off the power transistor (power FET) and performing on / off control of the power transistor, thereby controlling the duty ratio of the drive voltage. Arbitrary configurations can be applied, such as controlling.

  The engine ECU 78 is connected to an outside air temperature sensor 84 that detects the outside air temperature and a vehicle speed sensor 86 that detects the vehicle speed. Instead of the outside air temperature sensor 84, the outside air temperature To detected by the outside air temperature sensor 70 may be acquired by the air conditioner ECU 60.

  On the other hand, the electric pump 52 sends out engine coolant at a flow rate corresponding to the rotational speed R, and the engine ECU 78 controls the flow rate of the engine coolant by controlling the rotational speed R of the electric pump 52. To do. At this time, the engine ECU 78 controls the rotational speed R of the electric pump 52 by changing the duty ratio of the driving voltage of the electric pump 52, for example.

  That is, as shown in FIG. 4, the flow rate F of the engine cooling water increases as the rotational speed R of the electric pump 52 increases, and decreases as the rotational speed R of the electric pump 52 decreases.

  Between the coolant circuit 42 and the circulation circuit 58, the engine coolant is circulated at a ratio corresponding to the opening degree of the thermostat 46. That is, almost the total flow rate Fr of the engine coolant flowing through the engine radiator 40 is the flow rate F sent from the electric pump 52 (F = Fr + Fh).

  In the vehicle, a maximum value (maximum flow rate Fmax) and a minimum value (minimum flow rate Fmin) of the flow rate F of the engine cooling water are set, and the engine ECU 78 has a minimum number of revolutions Rmax and a minimum flow rate Fmax. The electric pump 52 is driven within the range of the rotational speed Rmin where the flow rate Fmin is obtained.

  This prevents the rotational speed R of the electric pump 52 from becoming unstable during extremely low rotations, and prevents temperature irregularities from occurring on the surfaces of the heater core 32 and the engine radiator 40, thereby enabling efficient heat exchange. It is made possible.

  In general, the rotational speed R of the electric pump 52 is controlled in accordance with the rotational speed of the engine 36 (engine rotational speed N) so that engine cooling water having a flow rate Fr corresponding to the engine rotational speed N flows to the engine radiator 40. Yes.

  FIG. 5A shows an outline of the rotational speed R of the electric pump 52 with respect to the engine coolant temperature Tw when the engine radiator 40 cools the engine coolant. The flow rate Fr of the engine radiator 40 is determined by the rotational speed R of the electric pump 52 and the opening degree of the thermostat 46.

  At this time, since the required flow rate Fr increases as the engine coolant temperature Tw increases, the rotational speed R of the electric pump 52 increases as the water temperature Tw increases. Further, when the water temperature Tw is lowered, the rotational speed R of the electric pump 52 is also lowered. When the electric pump 52 is turned on / off, hysteresis is given to the water temperature Tw.

  As the engine speed N increases, the amount of heat generated by the engine 36 also increases, and the water temperature Tw tends to increase. From here, as shown in FIG. 5B, the engine speed N can be used as a parameter to set the speed R of the electric pump 52 relative to the engine coolant temperature Tw.

That is, when the engine speed N is low, power saving can be achieved by suppressing the speed R of the electric pump 52 so as to reduce the flow rate Fr of the engine coolant compared to when the engine speed N is high. Can do. In FIG. 5B, as an example, the engine speed N is shown as the speeds N _{1 to} N ₅ (N ₁ > N ₂ > N ₃ > N ₄ > N ₅ ).

On the other hand, when the outside temperature To is high in summer or the like, the engine cooling water temperature Tw is likely to be high, and the cooling efficiency of the engine cooling water by the engine radiator 40 is also reduced. Further, in the cooling water circuit 42, the target temperature Two of the water temperature Tw of the engine coolant, is set low set temperature Ts ₁ of the thermostat 46, thereby, the water temperature Tw of the engine coolant set temperature Ts ₁ Is exceeded, the thermostat 46 is fully opened, and the engine coolant at a flow rate Fr corresponding to the rotational speed R of the electric pump 52 flows into the engine radiator 40 so that cooling of the engine coolant is promoted.

Further, the thermostat 46 narrows the flow path of the engine cooling water to the engine radiator 40 when the engine cooling water temperature Tw becomes lower than the set temperature Ts ₁ , whereby the flow rate Fr of the engine cooling water to the engine radiator 40 is reduced. Is lowered. Further, when the water temperature Tw becomes lower than the set temperature Ts ₂ , the thermostat 46 closes the flow path of the engine coolant to the engine radiator 40 so that cooling of the engine coolant is suppressed.

For this reason, when the engine coolant temperature Tw is equal to or lower than the set temperature Ts ₁ (Tw ≦ Ts ₁ ), the electric pump 52 is driven to rotate at a rotational speed R higher than necessary for cooling the engine coolant. Will be.

In addition, when the water temperature Tw exceeds the set temperature Ts ₁ and the thermostat 46 is in a fully opened state due to an increase in the outside air temperature To or the like, the actual electric power is compared with the rotational speed necessary for cooling the engine coolant. The rotational speed R of the pump 52 is low.

  From here, in engine ECU78 applied to this Embodiment, the rotation speed R of the electric pump 52 is set based on the water temperature Tw of engine cooling water. At this time, the engine ECU 78 switches the rotational speed R according to the vehicle traveling environment including the outside air temperature To or the outside air temperature To, thereby changing the flow rate Fr to the engine radiator 40 required for cooling the engine coolant. Accordingly, the rotational speed R of the electric pump 52 is set. In the following, the outside temperature To will be described as an example of the traveling environment of the vehicle.

  As shown in FIG. 6, the engine ECU 78 sets the rotational speed Rr of the electric pump 52 necessary for cooling the engine cooling water using the engine cooling water temperature Tw and the outside air temperature To as parameters.

  At this time, if the outside air temperature To is low, the cooling of the engine coolant can be suppressed, so the rotational speed R (the rotational speed Rr) of the electric pump 52 is lowered so that the flow rate Fr to the engine radiator 40 is reduced. However, the rotational speed R (the rotational speed Rr) of the electric pump 52 is set so that the flow rate Fr increases as the outside air temperature To increases.

  In addition, a temperature difference (hysteresis) is provided between the water temperature Tw when the driving of the electric pump 52 is started and the water temperature Tw when the driving of the electric pump 52 is stopped. When it is low, the driving / stopping of the electric pump 52 is prevented from being repeated.

  As described above, when the outside air temperature Tr is high, the cooling efficiency of the engine coolant in the engine radiator 40 decreases. From here, the engine ECU 78 changes the rotational speed Rr of the electric pump 52 relative to the engine coolant water temperature Tw in accordance with the outside air temperature To. At this time, the rotation speed Rr of the electric pump 52 with respect to the engine coolant temperature Tw is set higher when the outside air temperature To is higher than when the outside air temperature To is low.

In FIG. 6, as an example, the outside air temperature To is shown as the outside air temperature To _{1 to} To ₅ (To ₁ > To ₂ > To ₃ > To ₄ > To ₅ ).

On the other hand, in the air-conditioner 10 has set the opening degree S of the air mix damper 34 on the basis of the target outlet air temperature T _AO. Opening S of the air mix damper 34 is calculated the heater core 32 the temperature of the air passing through (post-heater core temperature Th), the temperature of the air bypassing the heater core 32 (post-evaporator temperature Te) and the target outlet air temperature T _AO It is set based on the mixing ratio r.

_{r = (T AO -Te) /} (Th-Te)
Here, the heater core post-temperature Th can be obtained by calculation from the temperature efficiency η of the heater core 32 and the engine coolant temperature Tw detected by the water temperature sensor 76.

Th = η · Tw + (1−η) · Te
The temperature efficiency η of the heater core 32 is determined for each heater core 32. As shown in FIG. 7, the temperature efficiency η of the heater core 32 varies according to the flow rate Fh of engine cooling water flowing through the heater core 32 and the air volume Vh of air passing through the heater core 32. At this time, by increasing the air volume Vh, the temperature efficiency η is lower than when the air volume Vh is small. In FIG. 7, the air volume Vh is shown as an air volume Vh _{1 to} Vh ₅ (Vh ₁ <Vh ₂ <Vh ₃ <Vh ₄ <Vh ₅ ) as an example.

  Therefore, in the air conditioner 10, the heater core post-temperature Th is increased by increasing the flow rate Fh of engine cooling water flowing through the heater core 32. Thereby, when the flow rate Fh is increased, the mixing ratio r is lowered, and the opening degree S of the air mix damper 34 is narrowed.

  When the opening degree S of the air mix damper 34 is narrowed, the heating capacity is large with respect to the heating load. At this time, by reducing the flow rate Fh of the engine cooling water flowing through the heater core 32, the electric pump The power saving of 52 can be achieved.

  From here, in air conditioner ECU60, as FIG.8 (A) shows, rotation speed R (henceforth rotation speed Rh) of the electric pump 52 required with respect to a heating load is set, and air conditioner ECU60. Then, based on the heating load, the rotational speed Rh of the electric pump 52 that sets the flow rate Fh that is the required flow rate of engine cooling water to the heater core 32 is set. Thereby, power saving of the electric pump 52 when air-conditioning (heating) the vehicle interior is achieved.

FIG. 8A conceptually shows the rotational speed R of the electric pump 52 with respect to the heating load. Specifically, the target blowout temperature _TAO and the outside air temperature To can be used as the heating load.

In FIG. 8 (B), by applying the target outlet air temperature T _AO to determine the heating load, it shows an example of the setting of the rotational speed Rh of the electric pump 52 with respect to the target air temperature T _AO. The heating load is larger when the target blowing temperature T _AO is higher than when the target blowing temperature T _AO is low.

From here, when setting the rotation speed Rh of the electric pump 52 based on the target blowing temperature T _AO , the rotation speed Rh is set to increase as the target blowing temperature T _AO increases.

  FIG. 8C shows an example of setting the rotation speed Rh of the electric pump 52 with respect to the outside air temperature To by applying the outside air temperature To to the determination of the heating load. The heating load is larger when the outside temperature To is low than when the outside temperature To is high.

  From here, when setting the rotation speed Rh of the electric pump 52 based on the outside air temperature To, it is set so that the rotation speed Rh increases as the outside air temperature To decreases.

The air conditioner 10 performs the cooling operation when the outside air temperature To is high, and the target blowing temperature _TAO is set low during the cooling operation.

  Thus, the air conditioner 10 is set so that the electric pump 52 can be stopped when the cooling operation is performed (the rotational speed Rh = 0). That is, when the outside air temperature To is high, the electric pump 52 can be stopped.

  When the air conditioner ECU 60 sets the rotation speed Rh of the electric pump 52 based on the heating load, the air conditioner ECU 60 requests the engine ECU 78 to drive the electric pump 52 so that the electric pump 52 is driven at the set rotation speed Rh.

  On the other hand, the engine ECU 78 compares the rotational speed Rh of the electric pump 52 required from the air conditioner ECU 60 with the rotational speed Rr of the electric pump 52 required for cooling the engine coolant in the engine radiator 40, whichever is higher. Is set as the rotation speed R of the electric pump 52, and the electric pump 52 is driven so that the set rotation speed R is obtained.

  Thus, when the outside air temperature To is low, the air-conditioner 10 can efficiently heat the vehicle interior, and when the outside air temperature To is high, the engine cooling water can be accurately cooled. Yes.

  The operation of the first embodiment will be described below.

In the air conditioner 10, when an operating condition is set by operating a switch on an operation panel (not shown) and an air conditioning operation is instructed, the air conditioning operation is performed so that the vehicle interior becomes the set temperature T _SET based on the operating condition and the environmental condition. Do.

At this time, the air conditioner ECU 60 sets the target blowing temperature T _AO based on the operating condition and the environmental condition, sets the target blowing temperature T _AO , the blower air volume Va, and the flow rate Fh of engine cooling water flowing through the heater core 32 (of the electric pump 52). The opening degree S of the air mix damper 34 is set based on the rotational speed R), the engine coolant temperature Tw, and the like.

Moreover, air conditioner ECU60, when air conditioning operation in automatic mode is instructed, to set the blower air volume Va and blowing mode and the like on the basis of the target outlet air temperature T _AO, based on these settings, the driving of the compressor 12 The driving of the blower fan 26 and the driving of the actuators 66B and 66C are controlled.

  As a result, the air conditioner 10 performs the air conditioning operation so that the vehicle interior is set to the set air conditioning state.

  Incidentally, a cooling device 38 is provided in a vehicle in which the air conditioner 10 is provided. In this cooling device 38, the drive of the electric pump 52 is controlled by the engine ECU 78.

  At this time, the air conditioner ECU 60 sets the rotational speed Rh of the electric pump 52 based on the heating load, and requests that the electric pump 52 be rotationally driven at the set rotational speed Rh or higher.

  That is, the heating capacity necessary for air-conditioning the passenger compartment is determined from the heating load, and the engine coolant is circulated so as to obtain this heating capacity.

  The engine ECU 78 sets a rotational speed Rr that provides a flow rate Fh of engine coolant necessary for cooling the engine coolant. Further, the engine ECU 78 compares the set rotational speed Rr with the rotational speed Rh requested from the air conditioner ECU 60, and sets the higher one to the rotational speed R of the electric pump 52. The electric pump 52 is driven so as to be obtained.

  FIG. 9 shows an outline of processing in the air conditioner ECU 60 at this time. When the air conditioning in the vehicle interior is instructed in the air conditioner ECU 60, the heating load is set in the first step 100, and in the next step 102, the rotation speed Rh of the electric pump 52 is set based on the heating load.

The air conditioner ECU 60 sets the target blowing temperature T _AO based on the heating load, and considers the outside air temperature To when setting the target blowing temperature T _AO . Here, the heating load may be a target outlet air temperature T _AO, it may be determined from outside air temperature To.

In this case, the map of the rotational speed Rh (see FIG. 8 (B)) with respect to the target air temperature _{T AO} or creates maps rpm Rh for the outside air temperature To (Fig. 8 (C) see) in advance, the air conditioner ECU60 By storing the value, it is easy to set an appropriate rotation speed Rh according to the heating load.

Further, in the air-conditioner 10, the required heating capacity is depending on the heating load, the minimum necessary heating capacity, since it is intended to conditioned air of the target outlet air temperature T _AO air mixing damper 32 fully opened state is obtained, A flow rate Fh of engine cooling water flowing to the heater core 32 is set from the water temperature Tw of the engine cooling water detected by the water temperature sensor 76, the blower air volume Va, and the post-evaporator temperature Te, and the rotational speed of the electric pump 52 from which the flow rate Fh is obtained. R may be calculated, and this rotational speed R may be set as the rotational speed Rh.

  When the rotation speed Rh is set, in the next step 104, the engine ECU 78 is requested to drive the electric pump 52 at the set rotation speed Rh.

  On the other hand, FIG. 10 shows an outline of circulation control of engine cooling water in the engine ECU 78. In this flowchart, in the first step 110, the outside air temperature To, the engine coolant temperature Tw, and the like are detected. In the next step 112, the rotational speed Rr of the electric pump 52 required for cooling the engine coolant is set based on the coolant temperature Tw and the outside air temperature To, for example, referring to a map according to FIG. To do.

  Here, the rotational speed Rr is set using the water temperature Tw and the outside air temperature To as parameters, but not limited to this, the outside air temperature To, the water temperature Tw, and the amount of cooling air introduced into the engine radiator 40 (the amount of air conduction). ) Based on the temperature efficiency of the engine radiator 40, etc., the flow rate of the cooling water required to set the water temperature Tw to the target temperature Two may be calculated, and the rotational speed Rr may be set from the calculated flow rate.

  When the rotation speed Rr is set in this way, in the next step 114 of the flowchart of FIG. 10, the rotation speed Rh requested from the air conditioner ECU 60 is read, and in the next step 116, the rotation speed Rh and the rotation speed Rr are compared. (For example, whether or not the rotational speed Rr exceeds the rotational speed Rh).

  Here, when the rotational speed Rr is equal to or higher than the rotational speed Rh (Rr ≧ Rh), an affirmative determination is made at step 116 and the routine proceeds to step 118, where the rotational speed Rr is the rotational speed when the electric pump 52 is driven. Set to R.

  When the rotational speed Rr is lower than the rotational speed Rh (Rr <Rh), a negative determination is made at step 116 and the routine proceeds to step 120 where the rotational speed Rh is set to the rotational speed R of the electric pump 52.

  When the rotational speed R of the electric pump 52 is set in this way, in step 122, drive control of the electric pump 52 is performed so that the electric pump 52 is driven at the rotational speed R.

  In the air conditioner ECU 60, when the outside air temperature To is low, the heating load increases, and the flow rate Fh of engine cooling water necessary for heating the passenger compartment increases, and accordingly, the rotational speed Rh also increases.

  Further, when the outside air temperature To is low, the flow rate Fr of engine cooling water to the engine radiator 40 decreases, and accordingly, the rotational speed Rr also decreases.

  At this time, since the electric pump 52 is driven at the rotation speed Rh requested from the air conditioner ECU 60, the vehicle interior can be accurately heated. Further, it is possible to prevent the engine core water from being supplied to the heater core 32 more than necessary.

  On the other hand, when the outside air temperature To is high, the heating load becomes small, and the air conditioner 10 performs the cooling operation. For this reason, it is not necessary to circulate engine coolant to the heater core 32.

  Further, as the outside air temperature To increases, the engine cooling water temperature Tw tends to increase, and the cooling capacity of the engine cooling water in the engine radiator 40 decreases.

  At this time, the engine ECU 78 is set so that the rotational speed Rr is higher than when the outside air temperature To is low, and the electric pump 52 is rotationally driven based on the rotational speed Rr.

  Thereby, the engine coolant can be reliably cooled, and the temperature rise of the engine 36 can be suppressed. At this time as well, the electric pump 52 is not driven to rotate at an unnecessarily high rotational speed R. Therefore, it is possible to prevent the power consumption from increasing in order to reliably cool the engine cooling water. Can do.

  That is, during heating, the engine core coolant is radiated by the heater core 32, and the engine 36 is simultaneously cooled by the engine coolant. For this reason, if the flow rate of the engine cooling water required for heating is large, the engine 36 is also cooled according to the heat radiation of the engine cooling water performed by the heater core 32, and the water temperature Tw of the engine cooling water is also lowered.

  When the thermostat 46 is closed due to the decrease in the engine coolant temperature Tw, the engine coolant does not flow to the engine radiator 40, and all the engine coolant flows to the heater core 32 and is used for the heating operation. The engine 36 is sufficiently cooled by the engine coolant circulated through the heater core 32.

  At this time, the flow rate of the engine cooling water necessary for heating may be obtained by driving the electric pump 52.

  On the other hand, when the flow rate of the engine coolant required for cooling the engine coolant using the engine radiator 40 is large, the temperature Tw of the engine coolant is high. At this time, the opening degree of the thermostat 46 is growing. As a result, the flow rate of the engine cooling water flowing to the engine radiator 40 increases, and the heat dissipation amount of the engine cooling water in the engine radiator 40 increases.

  Further, when the flow rate of the engine cooling water required for cooling the engine cooling water is larger, the water temperature Tw of the engine cooling water is still higher, and the thermostat 46 is fully opened.

  At this time, a flow rate required for cooling the engine coolant in the engine radiator 40 is obtained by driving the electric pump 52.

  Thus, by selecting the rotational speed R of the electric pump 52 so that the larger one of the flow rate of the engine coolant required for cooling the engine coolant and the flow rate of the engine coolant required for heating is obtained, Since both the cooling performance of the engine cooling water and the heating performance can be satisfied, and the electric pump 52 is not driven so as to generate an excessive flow rate of the engine cooling water, power saving is achieved.

  Therefore, in the cooling device 38, while saving the power of the electric pump 52, an accurate heating capacity of the air conditioner 10 is ensured when the outside air temperature To is low, and an appropriate value for the engine radiator 40 is obtained when the outside air temperature To is high. Engine cooling is possible.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. The basic configuration of the second embodiment is the same as that of the first embodiment described above. In the second embodiment, the same configuration as the first embodiment is described. Is omitted.

  The second embodiment described below is intended to save power when the electric pump 52 and the cooling fan 54 are provided. Mainly, here, the thermostat 46 is fully opened, the rotational speed of the electric pump 52 and the cooling fan 54 is appropriately controlled, and the power consumption is reduced by minimizing the sum of the power consumption of the electric pump 52 and the cooling fan 54. Plan.

  Here, in the engine ECU 78, when the electric pump 52 and the cooling fan 54 are driven, power saving is achieved while ensuring the cooling capacity of the engine cooling water.

  At this time, the engine ECU 78 supplies the engine radiator 40 with the flow rate Fr of the engine cooling water (the rotational speed Rr of the electric pump 52), the water temperature Tw of the engine cooling water detected by the water temperature sensor 82, and the outside air temperature detected by the outside air temperature sensor 84. Based on To and the vehicle running speed (vehicle speed vs) detected by the vehicle speed sensor 86, the rotational speed (cooling air volume) of the cooling fan 54 required for cooling the engine cooling water is set. As a result, the cooling capacity of the engine coolant is ensured while the number of rotations of the fan motor 80 is minimized.

  11A and 11B, the engine radiator 40 includes, for example, a large number of tubes 88 (see FIG. 11B) between the upper tank 92A and the lower tank 92B (see FIG. 11A). )), And the engine coolant flows through the tube 88 from the upper tank 92A toward the lower tank 92B.

  Further, for example, fins 90 in which iron plates or the like are formed in a wave shape are provided between the tubes 88, and heat transfer is performed between the tubes 88 and the fins 90 to cool the engine flowing in the tubes 88. Heat exchange is performed between the water and the air passing between the fins 90, and the engine coolant is cooled.

Here, the heat transfer rate (water side heat transfer rate) αw of the tube 88 and the heat transfer rate (air side heat transfer rate) αa of the fin 90 are respectively the flow rate of engine cooling water and the flow rate of air, that is, engine cooling water. The flow rate is approximately proportional to the 1/2 power of the air flow rate. From here, assuming that the flow rate (flow rate) Fw of the engine cooling water and the flow rate (flow rate) Fa of the cooling air, the heat transfer coefficients αa and αw are
αa = ka ₁・ Fa ^1/2 (1)
αw = kw ₁・ Fw ^1/2 (2)
It becomes. However, ka ₁ and kw ₁ are preset constants.

  On the other hand, the pressure loss ΔP when the fluid (engine cooling water) flows through the passage (tube 88) is obtained from the flow rate F of the fluid. In the second embodiment, the flow rate Fr of engine cooling water in the engine radiator 40 will be described as the flow rate F.

ΔP = k · F ² (3)
Where k is a constant. The power energy W at this time is
W = ΔP · F (4)
From here,
W = k · F ³ (5)
It becomes.

On the other hand, in the engine 36, the heat generation amount increases as the fuel injection amount increases. From here, the calorific value of the engine 36 can be set to h · m based on the fuel calorific value h and the fuel injection amount information m relating to the calorific value of the engine 36. Of these, the amount of heat loss Qw transferred to the engine coolant is
Qw = kn · (h · m)
Thus, this loss heat quantity Qw becomes the heat quantity cooled by the engine radiator 40. Become. Note that kn is a constant, for example, about 0.3.

  From this point, assuming that the target value of the engine cooling water temperature Tw is the target temperature Two, the air side of the engine radiator 40 and the engine cooling water side are between the target temperature Two and the air temperature Tra in front of the engine radiator 40. From the heat balance, the following equation (heat transfer equation) holds.

(Two-Tra) / Qw
= 1 / (αa · (At + φ · Af)) + (d / λ) · At + 1 / (αw · At)
Where At: heat transfer area of the tube 88, Af: heat transfer area of the fin 90, φ: fin efficiency, d: thickness of the tube 88 (wall thickness, see FIG. 11B), λ: heat of the tube 88 These are transmission rates, which are all determined for each engine radiator 40 and are known. From here, the previous equation is
(Two-Tra) ・ At / Qw
= 1 / (αa · (1 + φ · Af / At)) + d / λ + 1 / αw (6), and the heat transfer coefficient αa is as follows.

αa = 1 / [{(Two−Tra) At / Qw−d / λ−1 / αw} · (1 + φ · Af / At)] (7)
The air temperature Tra is the outside air temperature To detected by the outside air temperature sensor 84.

  When the condenser 14 of the air conditioner 10 is disposed on the vehicle front side of the engine radiator 40, the air temperature Tra is affected by the heat from the condenser 14.

  In this case, during the heating operation of the air conditioner 10 (the compressor 12 is off), the air temperature Tra becomes the outside air temperature To detected by the outside air temperature sensor 84, but during the cooling operation of the air conditioner 10 (the compressor 12 is on). From the refrigerant condensing temperature Tc obtained from the refrigerant pressure of the condenser 14 and the outside air temperature To, it can be obtained by the following equation.

Tra = ηc · Tc + (1−ηc) · Tr (8)
However, ηc is a constant and is the thermal efficiency (temperature efficiency) of the condenser 14, the refrigerant pressure and the refrigerant condensing temperature Tc are uniquely determined in a 1: 1 relationship, and the refrigerant pressure of the condenser 14 is determined by a pressure sensor (illustrated). (Omitted).

On the other hand, the flow rate Ff of air introduced as cooling air into the engine radiator 40 by the cooling fan 54, and the flow rate Fs (Fs = kv · vs) of air (vehicle speed air) introduced as cooling air when the vehicle travels, where vs: vehicle speed , Kv is a constant)
Fa = ka ₂ · αa ² (9) Fa = Ff + Fs (10)
The air flow rate Ff required for the cooling fan 54 is
Ff = Fa−Fs (11)
It becomes. The expression (10) can be approximately applied during low-speed traveling at a low vehicle speed vs. Only cooling using vehicle speed wind (air flow rate Fs from vehicle traveling) is possible at high-speed traveling at a high vehicle speed vs. Is sufficient and the cooling fan 54 is turned off. Therefore, in the range where the cooling fan 54 is operated, the equation (10) can be used.

On the other hand, the power consumption Wa of the cooling fan 54 for obtaining the flow rate Ff is:
Wa = ka ₃・ Ff ³ (12)
(Where ka ₃ is a constant).

In addition, the power consumption Ww of the electric pump 52 (electric motor 50) when the electric pump 52 is operated and the engine coolant of the flow rate F is caused to flow to the engine radiator 40 is
Ww = kw ₃・ F ³ (13)
Where kw ₃ is a constant. From this, the sum of the power consumption of the electric pump 52 and the cooling fan 54 (power consumption WT) is:
WT = Wf + Ww (14)
Thus, by obtaining the minimum power consumption WT at which the engine coolant temperature Tw becomes the target temperature Two, the power consumption Wf when the cooling fan 54 is driven, that is, the electric pump 52 and the cooling fan 54 are driven. The power consumption WT when being performed can be minimized.

On the other hand, since there is a substantially proportional relationship between the flow rate of the fluid and the driving voltage of the electric pump 52 and the cooling fan 54, the driving voltage Vf of the fan motor 80 and the driving voltage Vw of the electric pump 52 are
Vf = Kva · Ff (15)
Vw = Kvw · Fw (16)
(Where Kva and Kvw are proportional constants).

In addition, in the equations (15) and (16), feedback is not applied even if the engine coolant temperature Tw deviates from the target coolant temperature Two, so if a feedback term is added to this,
Vf = Kva · Ff + Kba · (Tw−Two) (17)
Vw = Kvw · Fw + Kbw · (Tw−Two) (18)
(Where Kba and Kbw are constants).

  As a result, the flow rate F of the engine cooling water that minimizes the power consumption WT, the flow rate Ff of the air by the cooling fan 54, and the electric pump from the equations (15) and (16) or (17) and (18) The driving voltage Vw of 52 and the driving voltage Vf of the fan motor 80 are obtained. By driving the electric pump 52 and the fan motor 80 based on the driving voltage Vw, the engine cooling water temperature Tw is maintained at the target water temperature Two. Power saving can be achieved.

  When the air flow rate Fa obtained from the equation (9) is equal to or lower than the flow rate Fs based on the vehicle speed vs, that is, when Ff ≦ 0 in the equation (11), the vehicle speed vs is relatively high, and the flow rate Fs. This means that the engine cooling water is sufficiently cooled, and at this time, it is not necessary to drive the cooling fan 54. Further, by using the equation (17), feedback control for driving the electric pump 52 is performed so that the water temperature Tw does not deviate from the target temperature Two.

  That is, if Ff ≦ 0 in the equation (11), Kva · Ff ≦ 0 in the equation (17). If Vf ≦ 0 together with the feedback, the cooling fan 54 is stopped.

  Further, when the drive voltages Vf and Vw are low, the rotation of the cooling fan 54 (fan motor 80) and the electric pump 52 (electric motor 50) becomes unstable. In order to prevent this, a lower limit value is set for each of the drive voltages Vf and Vw, and the electric pump 52 and the cooling fan 54 may be stopped below the lower limit value.

For example, as shown in FIG. 12A, the minimum voltage Vfmin and the maximum voltage Vfmax of the driving voltage Vf are set for the cooling fan 54 (fan motor 80), and the driving voltage Vf of the cooling fan 54 is set. operation value exceeds the set value a _1, starts driving of the cooling fan 54 at a minimum voltage Vfmin, according to the calculation value of the drive voltage Vf is increased, which increases the driving voltage Vf up voltage VFmax.

When the calculated value of the drive voltage Vf falls below the set value a ₁ , the drive voltage Vf is set to the minimum voltage Vfmin in the range from the set value a ₁ to the set value a ₂ (a ₁ > a ₂ ), and the cooling fan 54 is turned on. When the drive voltage Vf calculated value falls below the set value a ₂ (Ff <a ₂ ), the cooling fan 54 is stopped.

  Further, a minimum flow rate Fmin (rotation speed Rmin) and a maximum flow rate Fmax (rotation speed Rmax) are set in the electric pump 52. From here, as shown in FIG. The drive voltage Vw is set as the minimum voltage Vwmin, and the drive voltage Vw corresponding to the maximum flow rate Fmax is set as the maximum voltage Vwmax.

Here, the calculated value of the driving voltage Vw of the electric pump 52 exceeds the set value b _1, and starts driving the electric pump 52 at a minimum voltage Vwmin, in the range exceeding the set value a1, the maximum voltage Vwmax As an upper limit, the electric pump 52 is driven with the calculated drive voltage Vw.

When the calculated value of the drive voltage Vw decreases, the drive voltage Vw is set to the lowest voltage Vwmin in the range of the set value b ₁ to the set value b ₂ (b ₁ > b ₂ ), and the electric pump 52 is driven. When the calculated value of the drive voltage Vw falls below the set value b ₂ (F <b ₂ ), the electric pump 52 is stopped.

  Thereby, each of the electric pump 52 and the cooling fan 54 can be driven in a stable state.

  Here, the cooling control of the engine coolant in the cooling device 38 according to the second embodiment will be specifically described with reference to FIGS. FIG. 13 shows an outline of cooling control of engine cooling water. In the following description, the flow rate F of the engine cooling water to the engine radiator 40 is set to 10 l / min to 200 l / min, and this range is first set for each flow rate F chopped at a flow rate Δm = 10 l / min. The power consumption Ww of the electric pump 52 and the power consumption Wf of the cooling fan 54 are calculated, and the flow rate F that minimizes the power consumption WT is selected.

  Next, a flow rate F that minimizes the power consumption WT is selected for each flow rate F carved out in a predetermined range including the selected flow rate F at a newly set flow rate Δm = 1 l / min.

  For example, each flow rate Fn (n = 1, 2,..., I,..., 20) in which the flow rate F is in a range of 10 l / min to 200 l / min with Δm = 10 l / min is set. The power consumption WT is calculated by calculating the power consumption Ww and Wf, and the flow rate F when the calculated power consumption WT is minimum is selected.

If the flow rate F selected at this time is the flow rate F _i , the flow rate F _i−1 to the flow rate F _{i + 1} are engraved in a new region at Δm = (F _i −F _{i + 1} ) / 10 = 1 l / min. A target flow rate F _im (here, m = 1,..., J,..., 21) is newly set.

Thus, if the flow rate F of the power consumption WT is minimum flow rate _{F ij,} the flow rate _{F ij} the reference, a new calculation target region _{(e.g., F ij-1 ~F ij +} 1) and flow rate Delta] m (e.g., Δm = 0.1 l / min) is set, and the flow rate F that minimizes the power consumption WT is obtained.

  In this way, by repeating the selection of the flow rate F that minimizes the power consumption WT a predetermined number of times, a flow rate F of a predetermined effective number of digits (for example, 3 digits) is calculated, and the flow rate F and the flow rate F are calculated. The drive voltage Vw of the electric pump 52 and the drive voltage Vf of the cooling fan 54 are set from the corresponding flow rate Ff, and the electric pump 52 and the cooling fan 54 are controlled to be driven with the set drive voltages Vw and Vf.

  In the flowchart of FIG. 13, initial setting is performed in the first step 200. In this initial setting, the flow rate MS of the engine cooling water that minimizes the power consumption WT, the flow rate Mf by the cooling fan 54 are set to initial values (MS = 0, Mf = 0), and the variable M is set to the initial value ( M = 0). Here, as an example, the flow rate F is set at a flow rate Δm of 10 l / min, 1 l / min, and 0.1 l / min, and the variable M is a flow rate F set by M = 1 at Δm = 10 l / min. , M = 2 corresponds to the calculation for the flow rate F set at Δm = 1 l / min, and M = 3 corresponds to the calculation for the flow rate F set at Δm = 0.1 l / min.

  In the next step 202, it is confirmed from the value of the variable M whether or not a predetermined number of operations have been completed. At this time, since the variable M is initially set, M <3, so that an affirmative determination is made in step 202 and the routine proceeds to step 204.

  In this step 204, the variable M is incremented (M = M + 1), and then the number of operations Cn is set. Here, as an example, since the flow rate F is set in increments of 10 l / min from 10 l / min to 200 l / min in the first (M = 1), the number of computations Cn = 20, but the second (M = 2 ) In the third time (M = 3), the number of operations Cn is 21 times.

  From here, in step 206, it is confirmed whether or not the variable M = 1. If the variable M = 1, an affirmative determination is made in step 206 and the routine proceeds to step 208, where the number of operations Cn is set to 20 (Cn = 20). ). Further, when the variable M = 2 and 3, a negative determination is made at step 206 and the routine proceeds to step 210, where the number of computations Cn is set to 21 (Cn = 21).

  Next, at step 212, the counter i for counting the number of operations is reset (i = 0), and at step 214, it is confirmed whether or not the counter i has reached the number of operations Cn. At this time, if the counter i has not reached the number of operations Cn (i <Cn), an affirmative determination is made in step 214 and the routine proceeds to step 216, where the counter i is incremented (i = i + 1).

  In step 218, it is confirmed whether or not the variable M is M = 1. If M = 1, an affirmative determination is made in step 218 and the routine proceeds to step 220, where the flow rate F is set to F = 10 · i. . If the variable M is M ≠ 1, a negative determination is made in step 218 and the process proceeds to step 222. The flow rate F to be calculated is calculated based on the variable M and the counter i using the flow rate MS, for example, Calculate using the following equation.

F = MS-10 × 10 ^(2-M) +10 ^(2-M) × (i−1)
That is, in step 218 to step 222, the flow rate F to be calculated is set.

  In this way, when the flow rate F to be calculated is set, in step 224, the power consumption WT for the flow rate F is calculated.

  FIG. 14A shows an outline of the arithmetic processing executed at this time. In this flowchart, in the first step 230, the heat transfer coefficient αw on the tube 88 side is calculated based on the equation (3). Further, in step 232, the heat transfer coefficient αa on the fin 90 side is calculated based on the equation (7) using the heat transfer coefficient αw calculated in step 230.

  In the next step 234, the flow rate Fa of air required for cooling the engine coolant is calculated by the engine radiator 40 using the equation (9). In step 236, the flow rate Fa is calculated using the equation (11). The flow rate Ff of air by the cooling fan 54 necessary for obtaining is calculated.

  At this time, the outside air temperature To can be applied as the air temperature Tra, and when it is affected by the condenser 14 of the air conditioner 10, the temperature Tra calculated using the equation (8) is used.

When the air flow rate Ff is calculated in this way, in step 238, the power consumption Wf of the cooling fan 54 for obtaining the flow rate Ff is calculated using equation (12). In step 240, it calculates the power consumption Ww of the electric pump 52 in order to obtain a flow rate F _i that (13) using a formula, calculation target.

Thereafter, in step 242, a power consumption WT that is the sum of the power consumption Wf and the power consumption Ww is calculated (see equation (14)), the engine coolant flow rate F (F _i ), and the air flow rate F (Ff _i ) And power consumption WT (WT _i ) are stored in a memory (not shown).

When the power consumption WT and the flow rate Ff for one flow rate F are calculated in this way, in the flowchart of FIG. 13, the process returns to step 214 to perform the calculation for the next flow rate F (F _{i + 1} ).

  As a result, the calculation for the flow rate F in the preset range ends, and when the counter i reaches the number of calculations Cn (i = Cn), a negative determination is made in step 214 and the process proceeds to step 226.

  In step 226, the flow rate F that minimizes the power consumption WT is selected based on the calculation result.

  FIG. 14B shows an outline of the processing at this time. In this flowchart, in the first step 250, when the power consumption WT is the minimum from the power consumption WT stored in the memory. The flow rate F is selected.

  Thereafter, in step 252, the selected flow rate F is set to the flow rate MS used as a reference for the next calculation (MS = F), and in step 254, the air flow rate Ff of the cooling fan 54 corresponding to the selected flow rate F is set. , And set to the flow rate Mf.

  When the flow rate MS is set in this way, in the flowchart of FIG. 13, the process proceeds to step 202 and the next calculation is started. That is, when the calculation corresponding to the variable M = 1 is completed, the calculation corresponding to M = 2 is performed based on the calculation result.

  At this time, the calculation is performed within a predetermined range centering on the flow rate MS, and the flow rate F that minimizes the power consumption WT in the variable M = 2 is set.

  By repeating this, when the flow rate F having a predetermined effective number of digits can be set, a negative determination is made in step 202 and the process proceeds to step 228, and the electric pump 52 and the cooling fan 54 are driven based on the calculation result.

  FIG. 15 shows an outline of drive control executed by moving to step 228 in FIG.

  In this flowchart, in the first step 260, the driving voltage Vf of the cooling fan 54 is calculated from the air flow rate Ff by the cooling fan 54 when the power consumption WT is minimized using the equation (15) or (17). Calculate.

  In step 262, the drive voltage Vw of the electric pump 52 is calculated from the flow rate F of the engine coolant when the power consumption WT is minimized using the equation (16) or (18).

Thereafter, in step 264, checks whether the driving voltage Vf of the calculated cooling fan 54 has not reached the set value a _2, in step 266, whether the drive voltage Vf has become a set value a ₁ or more Check.

Here, when the drive voltage Vf has not reached the set value a ₂ (Vf <a ₂ ), an affirmative determination is made in step 264 and the process proceeds to step 268 to stop the cooling fan 54. If the drive voltage Vf is greater than or equal to the set value a ₁ (Vf ≧ a ₁ ), an affirmative determination is made in step 266 and the routine proceeds to step 270, where the cooling fan 54 is driven based on the calculated drive voltage Vf.

In the range where the calculated drive voltage Vf is (a ₂ ≦ Vf <a ₁ ), if the cooling fan 54 is driven, the driving of the cooling fan 54 is continued at the minimum voltage Vfmin, and the cooling fan 54 is stopped. If it is, the stop state is continued (see FIG. 12A).

On the other hand, in step 272, to check driving voltage Vw of the calculated electric pump 52 does not reach the set value b _2, in step 274, check whether the drive voltage Vw has become a set value b ₁ or more To do.

As a result, when the calculated drive voltage Vw has not reached the set value b ₂ (Vw <b ₂ ), an affirmative determination is made in step 272 and the process proceeds to step 276 to stop the electric pump 52. If the drive voltage Vw is greater than or equal to the set value b ₁ (Vw ≧ b ₁ ), an affirmative determination is made in step 274 and the routine proceeds to step 278, where the cooling fan 54 is driven based on the calculated drive voltage Vw.

In the range where the calculated drive voltage Vw is (b ₂ ≦ Vw <b ₁ ), if the electric pump 52 is driven, the drive of the electric pump 52 is continued at the minimum voltage Vwmin, and the electric pump 52 is in a stopped state. If it is, the stop state is continued.

  Thus, by controlling the drive of the electric pump 52 and the cooling fan 54, the water temperature Tw of the engine cooling water is maintained at the set temperature (target temperature) Two while suppressing the power consumption of the electric pump 52 and the cooling fan 54. can do.

  On the other hand, here, the electric pump 52 is driven based on the flow rate F of the engine cooling water that minimizes the power consumption WT, but the rotational speed R of the electric pump 52 at this time is determined by cooling the engine cooling water. The rotational speed Rr required for the air conditioner ECU 60 is compared, and the rotational speed Rh required by the air conditioner ECU 60 is compared. The higher rotational speed is set as the rotational speed R of the electric pump 52.

  In the cooling device 38, when the outside air temperature To is high and the rotational speed Rr is higher than the rotational speed Rh, the rotational speed Rr necessary for cooling the engine coolant is driven as the rotational speed R of the electric pump 52. At this time, power consumption of the electric pump 52 and the cooling fan 54 for cooling the engine coolant can be suppressed. That is, the engine coolant can be efficiently cooled while saving power.

  Further, the air temperature Tra shown in the equations (6) and (7) is a temperature that increases from the outside air temperature To as the outside air temperature To rises.

  As can be seen from the equation (7), when the air temperature Tra is increased, the temperature difference (Two−Tra) from the target temperature Two is decreased, thereby increasing the heat transfer coefficient αa.

  At this time, as shown in the equation (9), the air flow rate Fa, which is the air volume necessary for cooling the engine coolant, increases. If the vehicle speed vs is constant, the air flow rate by the cooling fan 54 is increased. By increasing Ff or increasing the flow rate F of the engine coolant, that is, the rotational speed R of the electric pump 52, it is possible to cool the engine coolant appropriately.

  Therefore, when the outside air temperature To is high, the rotational speed R of the electric pump 52 is set higher than when the outside air temperature To is low, and proper cooling of the engine coolant is performed.

  On the other hand, the cooling device 38 controls the drive of the electric pump 52 and the cooling fan 54 so that the engine coolant temperature Tw becomes the target temperature Two. For this reason, in the cooling water circuit 42, the thermostat 46 and the bypass path 56 can be omitted.

  In the equation (10), it has been described that it is established at the time of low-speed traveling. However, as shown in FIG. 16, a coefficient Kfs according to the vehicle speed vs of the vehicle is set, and this coefficient Kfs is used to drive at high speed. Even in the middle (a state where the speed vs is high), the flow rate Fa can be calculated with high accuracy.

  The coefficient Kfs is set to a value in the range of 0 <Kfs <1, and is large when the vehicle speed vs is low and decreases as the vehicle speed vs increases.

  When such a coefficient Kfs is used, it is sufficient if the flow rate Fa is calculated using the following equation instead of the equation (10).

Fa = Kfs · Ff + Fa
At this time, the air flow rate Ff by the cooling fan 54 is:
Ff = (1 / Kfs) · (Fa−Fs)
Can be computed as

  Thereby, the water temperature Tw of the engine cooling water is maintained at the substantially target temperature Two, and when the vehicle speed vs changes, the water temperature Tw can be prevented from increasing even temporarily.

  As described above, in the second embodiment, the flow rate Fa of the air passing through the engine radiator 40 by driving the vehicle or driving the cooling fan 54, the air temperature Tro (outside temperature To), the air side heat transfer of the engine radiator 40. Engine cooling water obtained from the rate αa, the flow rate F (flow rate Fr) of engine cooling water by the electric pump 52, the water-side heat transfer rate αw of the engine radiator 40, and the fuel injection amount information required for the heat dissipation amount required for the engine radiator 40 Of the electric pump 52 for setting the water temperature Tw of the engine cooling water to the target temperature Two using the heat transfer equation between the engine cooling water and the air in the engine radiator 40 using the received heat amount (loss heat amount Qw) of the engine. Based on the flow rate F of engine cooling water and the flow rate Fa of air that minimize the sum of the power consumption Ww and the power consumption Wf of the cooling fan 54. The electric pump 52 and the cooling fan 54 are driven.

  Thereby, it is possible to control the engine coolant temperature with high accuracy while saving power.

  When the cooling fan 54 introduces cooling air into the engine radiator 40 and also introduces cooling air into the condenser 14, drive control of the cooling fan 54 including cooling of the refrigerant in the condenser 14 can be performed. preferable.

  At this time, the driving voltage Vc of the cooling fan 54 corresponding to the refrigerant pressure Pc in the condenser 14 is obtained, and the higher one of the driving voltage Vc and the driving voltage Vf corresponding to cooling of the engine coolant is driven by the cooling fan 54. The voltage may be controlled so that the power consumption WT with the electric pump 52 is minimized.

In this case, as shown in FIG. 17, set values C ₁ and C ₂ (C ₁ > C ₂ ) are set for the calculated value of the refrigerant pressure Pc of the capacitor 14, and the calculated refrigerant pressure Pc is set. Thus, it is preferable to provide the drive voltage Vc with hysteresis.

  As a result, it is possible to secure the air volume necessary for cooling the condenser 14 while saving power, and the cooling capacity of the condenser 14 is insufficient and the refrigerant pressure becomes high, so that the compressor motor 62 that drives the compressor 12 It is possible to prevent the load from increasing. That is, it is possible to save power of the electric pump 52 and the cooling fan 54 and to save power of the compressor motor 62 while ensuring the cooling capacity of the air conditioner 10.

  In addition, this Embodiment demonstrated above does not limit the structure of this invention. For example, in the first embodiment, the rotational speed Rh of the electric pump 52 required for cooling the engine cooling water, that is, the engine cooling water to the engine radiator 40, based on the engine cooling water temperature Tw and the outside air temperature To. The flow rate Fr of the electric pump 52 is set, but the rotational temperature R of the electric pump 52 set based on the engine rotational speed N and the engine coolant water temperature Tw is corrected based on the external air temperature To. The rotational speed R of the electric pump 52 may be switched according to To.

  In addition, the cooling device of the present invention may have any configuration as long as it circulates engine cooling water by driving an electric pump and cools the engine cooling water or heats the interior of the vehicle using the engine cooling water. It can be applied to vehicles.

It is a schematic block diagram of the cooling device and vehicle air conditioner applied to this Embodiment. It is a schematic block diagram of the principal part of a vehicle air conditioner. It is a diagram which shows an example of the setting of the blower air volume with respect to target blowing temperature. It is a diagram which shows the flow volume of engine cooling water with respect to the rotation speed of an electric pump. (A) is a diagram showing an example of the number of rotations of the electric pump with respect to the engine cooling water temperature, and (B) is a diagram showing an example of the number of rotations of the electric pump with respect to the engine cooling water temperature using the engine speed as a parameter. It is. It is a diagram which shows an example of the setting of the rotation speed of the electric pump with respect to the water temperature of the engine cooling water which used the external temperature which concerns on 1st Embodiment as a parameter. It is a diagram which shows the temperature efficiency of the heater core with respect to the flow volume of engine cooling water. (A) is a diagram showing an outline of the rotational speed of the electric pump required for the heating load, and (B) is an electric pump required for the heating load when the target blowout temperature is applied as the heating load. The diagram which shows an example of rotation speed, (C) is a diagram which shows an example of rotation speed of the electric pump requested | required with respect to heating load when external temperature is applied as heating load. It is a flowchart which shows the outline of the circulation request | requirement of the engine cooling water in air-conditioner ECU which concerns on 1st Embodiment. It is a flowchart which shows the outline of the drive control of the electric pump which concerns on 1st Embodiment. (A) is the schematic which shows the external appearance of an engine radiator, (B) is a schematic sectional drawing which shows the principal part of an engine radiator. (A) is a diagram showing the outline of the drive voltage with respect to the calculated value of the driving voltage of the cooling fan, and (B) is a diagram showing the outline of the drive voltage with respect to the calculated value of the drive voltage of the electric pump. It is a flowchart which shows the outline of drive control of the electric pump and cooling fan which concern on 2nd Embodiment. (A) is a flowchart showing calculation of power consumption of the electric pump and the cooling fan based on the flow rate of engine cooling water, and (B) is a flowchart showing selection of the flow rate of engine cooling water that minimizes the calculated power consumption. It is. It is a flowchart which shows the outline of drive control of the electric pump and cooling fan based on the selected flow volume. It is a diagram which shows the outline of the coefficient applied to the calculation of the flow volume of the air according to a vehicle speed. It is a diagram which shows the outline of the drive voltage with respect to the calculated value of the refrigerant | coolant pressure of a capacitor | condenser.

Explanation of symbols

10 Air conditioner (Vehicle air conditioner)
14 Capacitor 32 Heater Core 36 Engine 38 Cooling Device 40 Engine Radiator 42 Cooling Water Circuit (Cooling Fluid Circuit)
52 Electric pump 54 Cooling fan 58 Circulating circuit 60 Air conditioner ECU (first setting means)
78 Engine ECU (second setting means, control means)
80 Fan motor 82 Water temperature sensor 84 Outside air temperature sensor (outside air temperature detecting means)
86 Vehicle speed sensor 88 Tube 90 Fin

Claims (3)

A coolant circuit that allows the engine coolant to circulate between the engine and the engine radiator;
A circulation circuit capable of circulating the engine coolant between the engine and a heater core of a vehicle air conditioner;
An electric pump that circulates the engine coolant according to the rotational speed by being driven to rotate to the coolant circuit and the circulation circuit;
An outside air temperature detecting means for detecting the outside air temperature;
When controlling the rotational drive of the electric pump, the electric pump rotates so that the flow rate of the engine coolant circulated through the coolant circuit increases as the outside air temperature detected by the outside air temperature detecting means increases. Control means to increase the number;
The vehicle cooling device characterized by including. A first setting means provided in the vehicle air conditioner for setting the flow rate of the engine coolant in the circulation circuit according to a heating load;
A second setting means for setting a flow rate of the engine coolant in the coolant circuit including the outside air temperature;
And the control means drives the electric pump so that the flow rate set by the first and second setting means is obtained.
The vehicular cooling device according to claim 1. When the engine coolant is circulated at a preset ratio between the coolant circuit and the circulation circuit by driving the electric pump, the first and second setting means are based on the flow rate. To set the rotation speed of the electric pump,
The control means drives the electric pump based on the higher rotation speed set by the first setting means or the rotation speed set by the second setting means;
The vehicular cooling device according to claim 2, wherein

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