JP5374302B2 - Radiator ventilation control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve the improvement of fuel economy by predicting the rise of a coolant temperature and maintaining the closed state of a flap as long as possible to harmonize both the cooling performance and the aerodynamic characteristics of an engine in a balanced manner. <P>SOLUTION: This radiator airflow rate control device compares a coolant temperature Tw with a warm-up completion determination value W (S10), and when determining that the warmup operation is completed by Tw&ge;W, compares a fuel consumption rate Ti calculated based on a fuel injection amount with a high temperature combustion determination value T set for each vehicle speed (S12) and when Ti is smaller than T, performs an operation mode 3 for closing an upper flap 16 which is provided to an air guide unit 12 and controls the flow rate of fresh air passing through a radiator 7 (S14). When Ti is equal to or larger than T, the control device performs an operation mode 1 or 2 for closing the upper flap 16 (S5, S6). <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a radiator air flow control device for a vehicle, which controls the air flow rate of outside air passing through a radiator using a wind guide unit.

  As is well known, in a vehicle such as an automobile, outside air (cooling air) is introduced from an opening formed in a front bumper, a front grill or the like provided at the front of the vehicle, and the introduced outside air is introduced into the front of the engine room. By passing the radiator disposed in the section, the coolant that has been heated by absorbing the heat of the engine is cooled.

  By the way, the outside air led to the engine room becomes air resistance during traveling and causes deterioration of fuel consumption. Therefore, it is desirable that the outside air introduced into the engine room is the minimum necessary.

  As a technique for controlling the outside air passing through the radiator, Patent Document 1 (Japanese Patent Laid-Open No. 2000-130167) provides an air guide unit between the front grille and the radiator, and the cooling water temperature is set to a set temperature (90 [° C. ]), The flap of the air guide unit is closed to limit the flow rate of the outside air to the radiator, thereby preventing overcooling of the cooling water flowing through the radiator and reducing the flow rate of the outside air introduced into the engine room. A technique for improving aerodynamic characteristics (cd value) by limiting the fuel efficiency is disclosed. When the cooling water temperature is equal to or higher than the set temperature (90 [° C.]), the cooling efficiency is increased by opening the flap of the air guide unit to increase the amount of cooling air passing through the radiator.

  However, in the technique disclosed in the above-mentioned document, when the cooling water exceeds the set temperature, the flap of the wind guide unit is opened. However, since the cooling water temperature absorbs heat from the engine and rises in temperature, for example, Even during high-load operation such as acceleration and climbing, the cooling water temperature is detected even if the cooling water temperature exceeds the set temperature, the flap of the air guide unit is opened, and cooling air is introduced into the radiator. Since the temperature rises, the temperature rise cannot be suppressed immediately, and there is a problem that engine performance is temporarily lowered due to insufficient cooling.

  In order to cope with this, it is conceivable to lower the set temperature for determining the opening and closing timing of the flap so that the cooling air is guided to the radiator relatively early. There is a problem that the cooling air volume to be introduced into the engine room becomes relatively long, and this causes air resistance, which leads to deterioration of fuel consumption.

  In view of the above circumstances, the present invention predicts an increase in cooling water temperature, maintains the closed state of the flap until the last minute, lengthens the closing time, and balances both the cooling performance of the engine and the aerodynamic characteristics in a well-balanced manner. Another object of the present invention is to provide a vehicle radiator air flow rate control device that can improve fuel consumption.

  To achieve the above object, a radiator flow control device for a vehicle according to the present invention includes a radiator that cools cooling water circulating in an engine, a wind guide unit that includes a flap that controls a flow rate of outside air to the radiator, and A control unit that controls opening and closing of the flap, and the control unit predicts high-temperature combustion by comparing a parameter related to engine load and a high-temperature combustion determination value that predicts that the engine set based on the vehicle speed burns at high temperature A high-temperature combustion determination means for determining whether or not to be performed, and when the parameter relating to the engine load is lower than the high-temperature combustion determination value in the high-temperature combustion determination means, the high-temperature combustion is not predicted and the flap is closed. If it is determined that the parameter relating to the engine load exceeds the high temperature combustion determination value, high temperature combustion is predicted. Characterized in that it comprises a flap operation control means for opening operation of the flap as is.

  According to the present invention, the parameter relating to the engine load and the high temperature combustion determination value set based on the vehicle speed are compared, and when the high temperature combustion is not predicted, that is, when the increase in the cooling water temperature is not predicted, it is provided in the wind guide unit. Since the outside air introduced into the engine room is limited by closing the flap that is being operated, the closed state of the flap can be maintained until the end of the warm-up operation. As a result, the flap closing time during traveling becomes longer, and both the cooling performance of the engine and the aerodynamic characteristics are harmonized in a well-balanced manner, and fuel efficiency can be improved.

Cross-sectional side view of a vehicle equipped with a radiator airflow control device Functional block diagram of radiator air flow control device Flowchart showing a radiator ventilation amount control routine Characteristic chart for setting the threshold value for opening and closing the flaps provided in the air guide unit

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a vehicle body front portion 1 of a private automobile which is an example of a vehicle is provided with a front bumper 3 at the front portion, a front grill 4 is provided above the front bumper 3, and an engine room E is provided inside. Is provided. Further, a front hood 5 is provided at the upper portion of the vehicle body front portion 1, and the upper portion of the engine room E is covered with the front hood 5 so as to be freely opened and closed. In the engine room E, a power unit such as the engine 6 is mounted.

  Further, a radiator 7 for cooling cooling water circulating in the engine 6 is disposed in front of the engine 6. A shroud 7a is provided at the rear portion of the radiator 7, and a radiator cooling electric fan (hereinafter referred to as "radio fan") (not shown) is provided in the shroud 7a. Further, a condenser 8 constituting a refrigeration cycle of the vehicle air conditioner is disposed in front of the radiator 7.

  This capacitor 8 is a well-known subcool capacitor, and is provided with a capacitor portion 8a in the upper portion and a subcool portion 8b (hatched portion in FIG. 1) in the lower portion (about ¼ position in the height direction). . The capacitor portion 8a and the subcool portion 8b are communicated with each other via a modulator (not shown). The gas-phase refrigerant that has flowed into the condenser unit 8a is cooled here, and most of the gas-phase refrigerant becomes liquid-phase refrigerant and flows into the modulator (not shown). Then, the refrigerant that has flowed into the modulator (not shown) is separated into a gas-phase refrigerant and a liquid-phase refrigerant, and the liquid-phase refrigerant flows into the subcool portion 8b.

  The refrigerant that has flowed into the subcooling portion 8b is further cooled to become a liquid-phase refrigerant close to 100%. Therefore, the condenser 8 can ensure the cooling capacity of the air conditioner by cooling at least the subcool portion 8b.

  The radiator 7, the shroud 7a, and the capacitor 8 are fixed to a radiator panel 9 (see FIG. 1) disposed in front of the radiator. The radiator panel 9 is formed in a substantially rectangular frame shape, and a pair of front side frames (not shown) that are disposed on the left and right sides in the vehicle width direction and extend in the front-rear direction of the vehicle body. Is fixed.

  A front bumper 3 integrated with the front grill 4 is connected to the radiator panel 9. A lower outside air inlet 3a is opened at the center of the front bumper 3 in the vehicle width direction. An upper outside air inlet 4a is formed at the center of the front grill 4 in the vehicle width direction.

  Further, a wind guide unit 12 is disposed in a space between the front bumper 3 and the front grill 4 and the radiator panel 9. The air guide unit 12 has a rectangular frame-shaped duct frame 12 a, and the rear part of the duct frame 12 a is fixed to the front part of the radiator panel 9. As shown in FIG. 1, the duct frame 12 a has a vehicle body longitudinal depth corresponding to the space between the front bumper 3 and the radiator panel 9, and has an area covering the entire capacitor 8.

  The lower introduction port 13a and the upper introduction port 13b are provided at positions corresponding to the outside air introduction ports 3a and 4a opened at the front bumper 3 and the front grille 4 at the lower and upper portions of the duct frame 12a of the air guide unit 12. And a blank panel 14 is disposed in the front surface between the two inlets 13a and 13b in a region where the wind does not flow. Further, flaps 15 and 16 are disposed on the front surfaces of the inlets 13a and 13b to open and close the inlets 13a and 13b and control the amount of outside air flowing through the radiator 7.

As shown in FIG. 1, the lower introduction port 13a has a single flap 15 extending in the vehicle width direction that opens and closes about half of the vertical direction. The upper introduction port 13b has three flaps 16 that open and close the entire upper introduction port 13b extending in the vehicle width direction. Each of the three flaps 16 has a horizontally long rectangular shape, and has an upper side. The two flaps 16 have a flat plate-like vertical cross-sectional shape, and the lowermost flap 16 has a cross-sectional shape of a square shape with the lower end side bent forward. Each flap 16 is provided with a support shaft 16a at the center in the vertical direction, and each support shaft 16a is connected to a drive motor 22 as an example of a drive actuator via a link mechanism (not shown). Yes. Since the flaps 16 perform the same operation via the link mechanism, they will be collectively referred to as the upper flap 16 in the following.

  On the other hand, both ends of a support shaft 15a connected to the upper end of the lower flap 15 are rotatably supported on both side surfaces of the duct frame 12a. The lower flap 15 is suspended by its own weight, and the electromagnet 23 is opposed to the lower end of the front surface of the lower flap 15 in the suspended state. The electromagnet 23 is fixed to the duct frame 12a. When the electromagnet 23 is energized, a magnetic field is generated and the lower end of the lower flap 15 is attracted.

  As shown in FIG. 2, the drive motor 22 and the electromagnet 23 are provided in the wind guide control unit 21. The wind guide control unit 21 is a single-function intelligent actuator in which a control unit 24, a motor drive unit 25, an electromagnetic drive unit 26, and a drive motor 22 are integrated.

  The control unit 24 is connected to a body integrated control unit (BCU) 31. Further, various control devices such as an engine control device (E / G_ECU) 33 and an air conditioner control device (A / C_ECU) 34 can communicate with the BCU 31 via an in-vehicle communication line 32 such as CAN (Controller Area Network) communication. It is connected to the. Each of these control devices 31, 33, 34, etc. is mainly composed of a microcomputer, and has a non-volatile storage means such as a well-known CPU, ROM, RAM, EEPROM or the like.

  The E / G_ECU 33 includes a vehicle speed sensor that detects a vehicle speed, an accelerator opening sensor that detects a depression amount of a driver's accelerator pedal, an engine speed sensor that detects an engine speed, an intake air amount sensor that detects an intake air amount, Based on various sensors for detecting the operating state of the engine 6, such as a water temperature sensor for detecting the cooling water temperature Tw [° C.] and an air-fuel ratio sensor for detecting the exhaust air-fuel ratio, the throttle valve provided in the electronically controlled throttle is opened. The engine 6 is comprehensively controlled, such as the fuel injection amount to the injector and the ignition timing for generating an ignition spark from the spark plug. Further, the E / G_ECU 33 controls the driving of the radio fan based on the cooling water temperature Tw, the vehicle speed, ON / OFF of an air conditioner switch and a refrigerant intermediate pressure switch which will be described later.

  The A / C_ECU 34 also includes an outside air temperature sensor that detects the outside air temperature Tou when the occupant turns on the air conditioner switch, an indoor temperature sensor that detects the vehicle interior temperature, a solar radiation sensor that detects the amount of solar radiation around the vehicle, Based on signals from sensors necessary for controlling the air conditioner, such as a pressure switch, a preset indoor temperature is set as a target temperature, and the air conditioner is controlled so that the vehicle interior temperature converges to the target temperature. The refrigerant intermediate pressure switch is provided on the high-pressure side line of the refrigerant passage, and is turned on when the refrigerant pressure rises and exceeds a predetermined threshold, and is in the off state when in a low pressure state.

  The BCU 31 is a gateway that connects control devices having different communication speeds. In this embodiment, parameters necessary for control executed in the control unit 24 of the wind guide control unit 21 are read via the BCU 31. .

  The control unit 24 of the wind guide control unit 21 performs energization / non-energization control on the electromagnet 23 that attracts the lower flap 15 and opening / closing control of the upper flap 16 based on various parameters. Specifically, the processing is performed in accordance with the radiator ventilation amount control routine shown in FIG.

  This routine is started when an ignition switch (not shown) is turned on. First, in step S1, the outside air temperature Tou detected by the outside air temperature sensor and a preset cooling temperature judgment value X [° C.] are obtained. Compare. The cooling temperature determination value X is a threshold value that can sufficiently obtain engine cooling even when the flaps 15 and 16 are closed. In this embodiment, the cooling temperature determination value X is for preventing control hunting. An offset temperature is set as the hysteresis.

  That is, the cooling temperature determination value X in the case where the outside air temperature Tou decreases and becomes the cooling temperature determination value X or less (Tou ≦ X) is a preset basic determination temperature α (for example, −5 [° C.]). Is set (X ← α), and the cooling temperature determination value X when the outside air temperature Tou rises and exceeds the cooling temperature determination value X is obtained by adding the offset temperature K1 (for example, +2 [° C.]) to the basic determination temperature α. The added value (X ← α + K1) is set. When the outside air temperature Tou is equal to or lower than the cooling temperature determination value X (Tou ≦ X), both the flaps 15 and 16 are basically closed to improve aerodynamic characteristics (cd value) and prevent excessive cooling. It is done.

  If Tou> X (= α + K1), the process proceeds to step S2, and if Tou ≦ X (= α), the process branches to step S3. In step S3, abnormality determination of the outside air temperature sensor is performed. In the present embodiment, whether or not the outside air temperature sensor is abnormal is checked based on whether or not the radio fan is rotating at high speed. The driving of the radio fan is controlled by the E / G_ECU 33 based on the vehicle speed and the cooling water temperature regardless of the output value of the outside air temperature sensor. When the outside air temperature is below the freezing point, it is difficult for the engine 6 to rise in temperature, and the cooling water temperature Tw becomes 100 [° C.] or less. Therefore, normally, the radio fan does not rotate at high speed (Hi) but stops or rotates at low speed.

  Therefore, if it is determined in step S3 described above that the radio fan is not rotating at high speed (Hi), it is determined that the outside air temperature sensor is normal, the process jumps to step S13, and the operation mode 3 is executed to execute the routine. Exit.

  On the other hand, when the radio fan is rotating at a high speed (Hi), it is determined that the outside air temperature sensor is out of order, and the process proceeds to step S4 to execute fail-safe control. First, in step S4, the cooling water temperature Tw detected by the water temperature sensor is compared with the high water temperature determination value H. The high water temperature determination value H is a threshold value for determining whether or not the cooling water temperature Tw is high. In this embodiment, an offset temperature is set as a hysteresis for preventing control hunting.

  That is, the high water temperature determination value H when the cooling water temperature Tw rises from the low temperature state and is equal to or higher than the high water temperature determination value H (Tw ≧ H) is a basic determination temperature β (for example, 104 [° C.]) set in advance. ) Is set (H ← β), and the high water temperature determination value H employed when the cooling water temperature Tw gradually decreases from a high temperature and becomes lower than the high water temperature determination value H is set to the basic determination temperature β and the offset temperature K2 ( For example, it is set to a value (H ← β + K2) obtained by adding −2 [° C.].

  If the cooling water temperature Tw is equal to or higher than the high water temperature determination value H (Tw ≧ H), the process proceeds to step S5, the operation mode 1 is executed, and the routine is exited. If the cooling water temperature Tw is less than the high water temperature determination value H (Tw <H), the process proceeds to step S6, the operation mode 2 is executed, and the routine is exited. Note that the process of performing the opening / closing operation of the upper flap 16 according to each of the operation modes 1 to 3 controlled in steps S5 and S6 and step S14 described later corresponds to the flap operation control means of the present invention.

In each of the operation modes 1 to 3, the following control operations are performed.

  The control signals corresponding to the operation modes 1 to 3 are output to the motor drive unit 25 that drives the upper flap 16 and the electromagnetic drive unit 26 that opens the lower flap 15.

  The motor drive unit 25 opens and closes the upper flap 16 by rotating the motor 22 forward or backward based on a control signal output from the control unit 24. The electromagnetic drive unit 26 energizes the electromagnet 23 in the case of an ON signal and deenergizes it in the case of an OFF signal in accordance with an ON / OFF signal output from the control unit 24. When the electromagnet 23 is energized, a magnetic field is generated and the lower flap 15 is attracted and closed. On the other hand, when the energization to the electromagnet 23 is interrupted (non-energized), the lower flap 15 becomes rotatable, and is suspended by its own weight when the vehicle is stopped, and is naturally released by the traveling wind while traveling.

  As shown in FIG. 2, the upper flap 16 has a structure that is opened and closed by the drive motor 22, but the lower flap 15 is maintained closed by the electromagnet 23. As described above, the lower flap 15 is suspended by its own weight with the upper end supported by the support shaft 15a, and the front lower end is attracted to the electromagnet 23 in this suspended state. Therefore, if the electromagnet 23 is de-energized during traveling, the lower flap 15 is opened by the traveling wind from the front, and thereafter the vehicle speed of the lower flap 15 decreases even if the electromagnet 23 generates a magnetic force. It will not close until the driving wind is weak.

  In this way, once the lower flap 15 is opened, the lower flap 15 can be closed again until the vehicle speed decreases and the traveling wind becomes weaker or until the vehicle stops. Therefore, the aerodynamic characteristics during running deteriorate. For this reason, in the present embodiment, even when the radio fan is rotating at a high speed (Hi), the lower flap is operated by executing the operation mode 2 until the cooling water temperature Tw exceeds the high water temperature determination value H. Fifteen closed states are maintained.

  On the other hand, when the process proceeds from step S1 to step S2, the outside air temperature Tou is compared with a preset freeze prevention determination value Y [° C.]. This anti-freezing determination value Y is a threshold value for determining whether or not each of the flaps 15 and 16 is likely to freeze. In this embodiment, the offset temperature is used as a hysteresis for preventing control hunting. Is set.

  If the outside air temperature Tou is equal to or lower than the freeze prevention determination value Y (X <Tou ≦ Y), the process proceeds to step S5, and the operation mode 1 is executed to exit the routine. That is, in this temperature range, moisture attached to the traveling wind guide unit 12 may condense, so the operation mode 1 is executed, all the flaps 15 and 16 are opened, and the flaps 15 and 16 are closed. It is prevented from being stuck by freezing in the state.

  The freeze prevention determination value Y is set at a basic determination temperature γ (for example, 3 [° C.]) set in advance (Y ← γ), and the outside air temperature Tou is decreased to become the freeze prevention determination value Y or less. In this case, the freeze prevention determination value Y is set to a value (Y ← γ + K3) obtained by adding an offset temperature K3 (for example, +2 [° C.]) to the basic determination temperature γ.

  On the other hand, if the outside air temperature Tou exceeds the freeze prevention determination value Y (Tou> Y), the process proceeds to step S7, and aerodynamic control is executed. In step S7, the outside air temperature Tou is compared with the air conditioner load determination value Z [° C.]. The air conditioner load determination value Z is a threshold value that increases the air conditioner load. In this embodiment, an offset temperature is set as hysteresis for preventing control hunting.

  That is, the air conditioner load determination value Z when the outside air temperature Tou falls below the air conditioner load determination value Z (Tou <Z) is set at a preset basic determination temperature δ (for example, 28 [° C.]). The air conditioner load determination value Z when the outside air temperature Tou rises and becomes equal to or higher than the air conditioner load determination value Z is equal to the basic determination temperature δ and the offset temperature K4 (for example, −2 [° C.]). Is set to a value obtained by adding (Y ← γ + K4).

  When Tou ≧ Z, the outside air temperature Tou is high. Therefore, if the air conditioner switch is turned on, the refrigerant pressure gradually increases due to the endothermic temperature absorption. On the other hand, in the state where Tou <Z, the refrigerant pressure does not become so high because the outside air temperature Tou is low. Therefore, when Tou ≧ Z, the process proceeds to step S8, and first, it is checked whether or not the air conditioner switch is ON. On the other hand, if Tou <Z, the process proceeds to step S9.

  And when it determines with an air-conditioner switch being OFF by step S8, it jumps to step S10. If it is determined that the air conditioner switch is ON, the process proceeds to step S11 to check the state of the refrigerant intermediate pressure switch. When the refrigerant intermediate pressure switch is ON, the refrigerant pressure has increased. Therefore, the process returns to step S5, the operation mode 1 is executed, the flaps 15 and 16 are opened, and the routine is exited. As a result, when both the flanges 15 and 16 are opened, traveling air (cooling air) is introduced into the condenser 8 of the air conditioner through the upper and lower inlets 13a and 13b, so that an increase in the refrigerant pressure is suppressed and the cooling capacity is increased. It is done.

  On the other hand, if the refrigerant intermediate pressure switch is OFF, the process jumps to step S15, and the coolant temperature Tw is compared with the high coolant temperature determination value H. When Tw ≧ H, it is necessary to improve the cooling performance of the radiator 7, so the process returns to step S5, the operation mode 1 is executed, the flaps 15 and 16 are opened, and the routine is exited. If Tw <H, the process proceeds to step S6, where the operation mode 2 is executed, only the upper flap 16 is opened, and the routine is exited.

  When the process proceeds from step S7 to step S9, it is checked whether or not the refrigerant intermediate pressure switch is ON. Here, after the air conditioner switch is turned on, it is checked whether or not the refrigerant intermediate pressure switch is turned on. If the air conditioner switch is turned off, the refrigerant intermediate pressure switch remains off, and the process proceeds to step S10. . Even if the air conditioner switch is on, if the refrigerant intermediate pressure switch is off, the process proceeds to step S10. On the other hand, when the refrigerant pressure rises and the refrigerant intermediate pressure switch is turned on, that is, the outside air temperature Tou is less than the air conditioner load determination value Z (Tou <Z), the air conditioner switch is turned on. When the refrigerant pressure increases and the refrigerant intermediate pressure switch is ON, the process proceeds to step S15. Since the processing in step S15 has already been described, the description thereof is omitted.

  When the process proceeds from step S8 or step S9 to step S10, the coolant temperature Tw is compared with the warm-up end determination value W. The processing here corresponds to the warm-up operation end determination means of the present invention.

  The warm-up end determination value W is a threshold value for determining the end of the warm-up operation, and is a value lower than the temperature at which the radio fan operates based on the coolant temperature Tw. In this embodiment, an offset temperature is set as the hysteresis for preventing the control hunting in the warm-up completion determination value W.

  That is, the warm-up end determination value W when the coolant temperature Tw rises and becomes equal to or higher than the warm-up end determination value W (Tw ≧ W) is a basic determination temperature η (for example, 98 [° C.]) that is set in advance. (W ← η), and the warm-up end determination value W when the cooling water temperature Tw is lower than the warm-up end determination value W is set to the basic determination temperature η and the offset temperature K5 (for example −2 [° C.]) is added to the value (W ← η + K5). This warm-up completion determination value W is set to a temperature lower than the temperature at which the thermostat valve provided in the cooling system starts to open. The thermostat valve limits the amount of cooling water flowing to the radiator 7 by closing when the cooling water temperature is low, and gradually opens as the cooling water temperature rises to increase the amount of cooling water flowing to the radiator 7.

  If Tw ≧ W, it is determined that the warm-up operation has ended, and the process proceeds to step S12. If Tw <W, it is determined that the warm-up is being performed, and the process proceeds to step S14. In step S14, the operation mode 3 is executed, the flaps 15 and 16 are all closed, and the routine is exited.

  When the coolant temperature Tw is lower than the warm-up end determination value W (Tw <W), the coolant is not supplied to the radiator 7 because the thermostat valve is closed. Therefore, even if the introduction of outside air to the radiator 7 is shut off, the cooling water temperature does not become abnormally high. Moreover, since all the flaps 15 and 16 are closed, the outside air introduced into the engine room E is limited, so that the engine 6 is prevented from being overcooled and can be quickly raised to an appropriate temperature.

  On the other hand, when it is determined that Tw ≧ W and the process proceeds to step S12, the fuel injection amount set by the E / G_ECU 33 is read, and based on this fuel injection amount, a fuel consumption rate (per unit time) as an example of an engine load parameter is read. (Fuel injection amount) Ti is calculated, and the fuel consumption rate Ti is compared with the high-temperature combustion determination value T. Note that the processing at this step corresponds to the high-temperature combustion determination means of the present invention.

  This high temperature combustion determination value T is a threshold value for predicting whether or not the combustion by the actual fuel consumption rate Ti becomes high temperature combustion, and as shown in FIG. 4, based on the vehicle speed detected by the vehicle speed sensor, It is set with reference to a preset high temperature combustion determination value table.

  The upper flap 16 is basically controlled to open and close based on the vehicle speed and the coolant temperature Tw. However, even if the upper flap 16 is opened after detecting the high temperature of the cooling water temperature Tw, the cooling water temperature Tw is in the process of rising, so that overheating is likely to occur. Therefore, generally, the coolant temperature Tw that the upper flap 16 opens tends to be set low. As a result, the opening period of the upper flap 16 becomes longer, and during that time, the traveling wind enters the engine room E and becomes resistance, resulting in a deterioration in fuel consumption.

  On the other hand, in this embodiment, in step S12, when the increase in the coolant temperature Tw is predicted from the fuel injection amount (fuel consumption rate) Ti per unit time and the operating state of the radio fan is ignored, the fuel consumption rate Ti is The flaps 15 and 16 are closed until the high-temperature combustion determination value T set based on the vehicle speed is exceeded (operation mode 3). Therefore, even if the cooling water temperature Tw rises, there is no shortage of cooling. Since both the flaps 15 and 16 can be kept closed until the temperature, the aerodynamic characteristics at the time of traveling are improved and the fuel consumption is improved. In addition, good heating performance can be ensured during cold running.

  By the way, as shown in FIG. 4, the high-temperature combustion determination value T has a fuel consumption rate curve when traveling at a constant flat speed (hereinafter, referred to as “constant traveling speed flat curve”) and a fuel consumption rate when traveling at a constant speed on an uphill road. It is set between the curves (hereinafter, referred to as “climbing constant speed traveling curve”). The flat land constant speed running curve and the uphill road constant speed running curve are fixed values obtained in advance for each vehicle type through experiments and the like. Therefore, the high temperature combustion judgment value table includes the flat land constant speed running curve and the uphill road constant. A high-temperature combustion determination value T that is stored between the two is stored based on the fast running curve.

  The flat ground constant speed running curve is a fuel necessary for traveling on a flat ground at a constant vehicle speed, and is obtained in advance for each vehicle type from experiments and the like. Since this driving state is the driving with the best fuel consumption, the fuel injection amount is small and the heat generation amount is also small. Therefore, even if the flaps 15 and 16 are closed, it is possible to suppress an increase in the coolant temperature Tw by the traveling wind introduced into the engine room E. Moreover, aerodynamic characteristics (cd value) can be improved by closing both the flaps 15 and 16.

  On the other hand, the uphill road constant speed traveling curve shown in the figure is a fuel consumption rate curve when traveling on an uphill road of, for example, about 8% at a constant speed. Under such severe driving conditions, the fuel consumption rate increases as the vehicle speed increases, and the temperature of the engine 6 also rises. Therefore, if the flaps 15 and 16 are kept closed, the engine 6 is not cooled due to insufficient cooling. Overheating is induced.

  Accordingly, the high-temperature combustion determination value T is provided between two constant speed travel curves, and at least the upper flap 16 is closed when the actual fuel consumption rate is lower than the flat land constant speed travel curve, and the uphill road constant speed travel is performed. If it is higher than the curve, it must be opened.

  In the present embodiment, as shown in FIG. 4, the high-temperature combustion determination value T is between two constant speed travel curves in the medium vehicle speed region (60 to 110 [Km / h] in the figure). The vehicle speed range (0 to 60 [Km / h] in the figure) and the high vehicle speed area (110 [Km / h] or more in the figure) are two constants. A constant value connected between both ends of the high-temperature combustion determination value T in the medium vehicle speed region described above is set between the high-speed running curves.

  In this case, the high-temperature combustion determination value T may be proportionally increased in accordance with the vehicle speed from the idling state where the vehicle speed is 0 [Km / h] between the two constant speed traveling curves to the high vehicle speed range. Although it is conceivable, at the vehicle speed of 0 [Km / h], the actual fuel consumption rate may exceed the high temperature combustion determination value T, and the upper flap 16 may open. On the other hand, in the high vehicle speed region, the fuel injection amount increases, the actual fuel consumption rate increases, and the heat generation amount of the engine 6 increases. Therefore, in order to prevent overheating of the engine 6, there is an operating region in which the upper flap 16 must be opened, that is, there is a fuel injection amount that generates a heat generation amount that induces overheating. This is set to 110 [Km / h] in the present embodiment.

  Therefore, in this embodiment, the high-temperature combustion determination value T is set to a constant value that does not depend on the vehicle speed in the low vehicle speed region and the high vehicle speed region, and is set to a proportional value that increases according to the vehicle speed in the middle vehicle speed region. Thus, the high temperature combustion judgment value T can be easily derived. The high-temperature combustion determination value T can be calculated according to the vehicle speed from a preset primary equation without using a table search.

  If Ti <T, it is determined that the engine 6 does not generate heat at a high temperature, and the process proceeds to step S13. If Ti ≧ T, it is determined that the engine 6 generates heat at a high temperature, and the process proceeds to step S15.

  In step S13, it is checked whether the radio fan is rotating at high speed (Hi). As described above, the driving of the radio fan is controlled by the E / G_ECU 33 based on the vehicle speed and the coolant temperature. Therefore, even if it is determined that the engine 6 does not generate high temperature heat at the current fuel consumption rate Ti, it is necessary to introduce cooling air into the radiator 7 if the radiator fan has already been rotating at a high speed. Branches to step S15. Such a situation is, for example, when the vehicle interior temperature is abnormally high in a low vehicle speed region including when the vehicle is stopped, and the A / C_ECU 34 rotates the engine at a high speed (Hi) regardless of the cooling water temperature Tw. From the viewpoint of cooling, it is not necessary to open the flaps 15 and 16, but the case where the cooling performance of the air conditioner is ensured and the vehicle interior needs to be rapidly cooled is applicable.

  On the other hand, when the radio fan is rotating at a low speed or stopped, the process proceeds to step S14, the operation mode 3 is executed, the flaps 15 and 16 are all closed, and the routine is exited. In a state where the radio fan is rotating at a low speed or stopped, the engine 6 does not generate heat at a high temperature even with the current fuel consumption rate Ti, so it is determined that the radio fan is stopped or the low speed rotation is continued. Therefore, in such a situation, the aerodynamic characteristics (cd value) can be improved by closing all the flaps 15 and 16 in the operation mode 3.

  Thus, according to the present embodiment, even when the coolant temperature Tw exceeds the warm-up completion determination value W (Tw ≧ W), the fuel consumption for each vehicle speed is not immediately opened without opening the upper flap 16. Since the rise of the cooling water temperature Tw is predicted based on the rate and the closed state of the flaps 15 and 16 is maintained until the last minute, the closing time of both the flaps 15 and 16 during traveling becomes longer, and the engine 6 This improves the combustion state, improves the aerodynamic characteristics and improves the fuel efficiency, and also ensures good heating performance when traveling in cold regions. As a result, both the cooling performance and aerodynamic characteristics of the engine 6 can be harmonized in a well-balanced manner.

  In addition, this invention is not restricted to embodiment mentioned above, For example, the engine employ | adopted may be not only a gasoline engine but a diesel engine.

6 ... Engine 7 ... Radiator 12 ... Wind guide unit,
16 ... upper flap,
21 ... Air guide control unit,
22: Drive motor,
24 ... control unit,
33 ... E / G_ECU,
34 ... A / C_ECU,
E ... Engine room H ... High water temperature judgment value T ... High temperature combustion judgment value Ti ... Fuel consumption rate Tou ... Outside air temperature Tw ... Cooling water temperature W ... Warm-up completion judgment value X ... Cooling temperature judgment value

JP 2000-130167 A

Claims (3)

A radiator for cooling the cooling water circulating in the engine;
An air guide unit having a flap for controlling the amount of outside air to the radiator;
A control unit for controlling opening and closing of the flap,
The controller is
A high-temperature combustion determination means for determining whether or not high-temperature combustion is predicted by comparing a parameter relating to engine load and a high-temperature combustion determination value for predicting that the engine set based on the vehicle speed is subjected to high-temperature combustion;
When the parameter related to the engine load is lower than the high-temperature combustion determination value, the high-temperature combustion determination means closes the flap assuming that high-temperature combustion is not predicted, and the parameter related to the engine load exceeds the high-temperature combustion determination value. And a flap operation control means for opening the flap when it is determined that high-temperature combustion is predicted.   The radiator flow rate control device for a vehicle according to claim 1, wherein the parameter relating to the engine load includes any one of a fuel injection amount, an engine torque value, and an engine load.   The high temperature combustion determination value set by the high temperature combustion determination means is set between a parameter related to the engine load during traveling at a constant speed on a flat ground and a parameter related to the engine load during traveling at a constant speed on an uphill road. The radiator flow rate control device for a vehicle according to claim 1 or 2, characterized in that:

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