JP2007055524A - Vehicular outdoor heat exchanger cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular outdoor heat exchanger cooling device with an outdoor heat exchanger arranged below a floor of a vehicle which is capable of avoiding troubles of degradation of the cooling capacity by the exhaust heat of an engine for traveling. <P>SOLUTION: The vehicular outdoor heat exchanger cooling device comprises an outdoor heat exchanger 12 which is arranged below a floor of a vehicle to perform the heat exchange between air and a refrigerant, a cooling fan 21 for feeding air to the outdoor heat exchanger 12, and a control device 33 which feeds air from a forward side to a backward side of the vehicle by rotating the cooling fan 21 forwardly, and feeds air from the backward side to the forward side of the vehicle by turning the rotational direction of the cooling fan 21 when the vehicle is stopped. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicular outdoor heat exchanger cooling device in which an outdoor heat exchanger is disposed under a vehicle floor, and is particularly suitable for use in a refrigerator car.

  Conventionally, in a freezing vehicle in which a freezer is mounted later on the cargo bed of a freight vehicle, only the outdoor heat exchanger (condenser) for air conditioning of the passenger compartment mounted in the engine room has insufficient refrigerant condensing capacity. Some condensers are installed separately from the air conditioning condenser.

In this type of freezer, it is not possible to secure a space for mounting a freezer condenser in the engine room. For example, as in Patent Document 1, a freezer condenser is placed under the floor of a cargo bed, in other words, a freezer. It is arranged under the floor of the car (hereinafter referred to as the vehicle floor). Specifically, the condenser is disposed at the vehicle front-rear direction center and the vehicle right side under the vehicle floor.
Japanese Patent Laid-Open No. 2005-008088

  By the way, in a low-floor type freezing vehicle in which the floor surface of the freezer is kept low, the interval between the ground and the floor surface of the freezer is narrowed, so a condenser is mounted on the conventional part shown in Patent Document 1. I can't. Therefore, in a low-floor type refrigerator truck, measures are taken to place a condenser at the rearmost part under the vehicle floor where a condenser mounting space is barely left.

  FIG. 4 is a diagram illustrating a mounted state of the condenser in the low-floor type refrigerator truck. The condenser 12 is disposed so that the heat exchange core surface faces in the vehicle front-rear direction due to restrictions on the mounting space, and air is blown from the vehicle front side toward the vehicle rear side by the cooling fan 21 as indicated by an arrow A. It has come to be.

  However, in such an arrangement of the condenser 12, when the vehicle is stopped or at a low vehicle speed, the cooling capacity of the condenser 12 is reduced by the exhaust heat of the traveling engine 20. This is due to the following reason.

  In other words, the air heated by the exhaust heat of the traveling engine 20 is sucked to the condenser 12 by the cooling fan 21 as indicated by an arrow E. When the vehicle is traveling, the heated air is caught under the vehicle floor. Since it is cooled by the traveling wind, the intake air temperature of the condenser 12 does not rise significantly.

  On the other hand, when the vehicle is stopped or when the vehicle speed is low, running wind is not generated or is a breeze, so high-temperature air heated by engine exhaust heat is sucked into the condenser 12 without being cooled by running wind. End up.

  As a result, when the vehicle is stopped and when the vehicle speed is low, the intake air temperature of the condenser 12 is remarkably increased, and the condensation of the refrigerant in the condenser 12 becomes insufficient. That is, the cooling capacity of the condenser 12 is reduced.

  In view of this, there can be considered a means for avoiding the intake of the high-temperature air heated by the engine exhaust heat by setting the air blowing direction of the cooling fan 21 in the direction opposite to the arrow A, that is, the direction from the vehicle rear side toward the vehicle front side.

  However, if the air blowing direction of the cooling fan 21 is opposite to the direction of the arrow A, the air blown by the cooling fan 21 faces the running air F when the vehicle travels, which makes it difficult to blow air to the condenser 12. is there.

  In view of the above points, an object of the present invention is to avoid a problem in which the cooling capacity of a vehicular outdoor heat exchanger cooling device in which an outdoor heat exchanger is disposed under a vehicle floor is reduced due to exhaust heat of a traveling engine. .

In order to achieve the above object, the present invention provides an outdoor heat exchanger (12) disposed under a vehicle floor and exchanging heat between air and a refrigerant,
A cooling fan (21) for blowing air to the outdoor heat exchanger (12);
During normal times, the cooling fan (21) is rotated forward to blow air from the front of the vehicle toward the rear of the vehicle. When the vehicle is stopped, the rotation direction of the cooling fan (21) is reversed to allow the air to flow rearward. A control device (33) for blowing air from the vehicle toward the front of the vehicle is provided.

  According to this, since the cooling fan (21) can blow air from the rear of the vehicle toward the front of the vehicle only when the vehicle is stopped, the high-temperature air heated by the exhaust heat of the traveling engine is exchanged with the outdoor heat when the vehicle is stopped. The container (12) can be prevented from inhaling.

  Further, since the cooling fan (21) normally blows air from the front of the vehicle to the rear of the vehicle during normal times, the air blown by the cooling fan (21) does not face the traveling wind (F), and thus the outdoor heat exchanger. The ventilation to (12) is possible.

  As a result, in the vehicular outdoor heat exchanger cooling device in which the outdoor heat exchanger is disposed under the vehicle floor, it is possible to avoid a problem that the cooling capacity is reduced due to exhaust heat of the traveling engine.

  Further, in the present invention, the control device (33) may reversely rotate the rotation direction of the cooling fan (21) when the condenser front surface temperature (Ta) is equal to or higher than a predetermined temperature in addition to when the vehicle is stopped.

  According to this, it is possible to prevent the outdoor heat exchanger (12) from sucking high-temperature air heated by engine exhaust heat not only when the vehicle is stopped but also at a low vehicle speed.

  Further, in the present invention, specifically, the outdoor heat exchanger (12) is disposed on the vehicle rear side of the traveling engine (20) at a position where hot air heated by engine exhaust heat flows. ing.

  In addition, the code | symbol in the bracket | parenthesis of each means described in a claim and this column shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall configuration diagram of a vehicle air conditioner to which a vehicle outdoor heat exchanger cooling device according to a first embodiment is applied. FIG. 2 is a schematic cross-sectional view of a vehicle (refrigerated vehicle) on which the vehicle air conditioner of FIG. 1 is mounted.

  The refrigeration cycle 10 constituting the vehicle air conditioner includes one compressor 11, one condenser 12, and two evaporators 13 and 14 connected in parallel, and the two evaporators 13 and 14 provide a vehicle 15. The vehicle compartment 16 is cooled and the freezer 17 is cooled. The condenser 12 corresponds to the outdoor heat exchanger in the present invention.

  In the refrigeration cycle 10, a compressor 11 that sucks and compresses refrigerant is disposed in the frontmost engine room of the vehicle 15, and is rotationally driven by a traveling engine 20 via a pulley 18, a belt 19, and the like.

  The compressor 11 may be a variable capacity compressor that can adjust the refrigerant discharge capacity by changing the discharge capacity, or a fixed capacity type compressor that adjusts the refrigerant discharge capacity by changing the operating rate of the compressor operation by switching the electromagnetic clutch. Any of the machines may be used.

  The condenser 12 that cools and condenses the high-temperature and high-pressure refrigerant discharged from the compressor 11 is disposed under the vehicle floor, that is, under the freezer 17 and at the rearmost part of the vehicle. The condenser 12 is disposed with the heat exchange core surface in the vehicle front-rear direction due to restrictions on the mounting space.

  A cooling fan 21 including an axial fan is disposed further on the vehicle rear side of the condenser 12. The cooling fan 21 is driven by the electric motor 22 so that air is blown to the condenser 12.

  When the electric motor 22 rotates in the forward rotation direction, the cooling fan 21 formed of an axial fan rotates in the forward rotation direction, and air is blown from the front of the vehicle toward the rear of the vehicle as indicated by an arrow A. On the other hand, when the electric motor 22 rotates in the reverse rotation direction, the cooling fan 21 composed of an axial fan rotates in the reverse rotation direction, and air is blown from the rear of the vehicle toward the front of the vehicle as indicated by an arrow B. .

  The refrigerant condensed in the condenser 12 is separated into gas and liquid in the liquid receiver 23, and the liquid refrigerant flowing out of the liquid receiver 23 is branched and sent to the two expansion valves 24 and 25. The expansion valves 24 and 25 serve as decompression means for the refrigeration cycle 10, and decompress and expand the liquid refrigerant.

  One of the two evaporators 13, 14 is a cooling heat exchanger that cools the air by the low-temperature and low-pressure refrigerant flowing out of the expansion valve 24 absorbing heat from the air and evaporating. Yes, the space in the passenger compartment 16 is cooled.

  The compartment evaporator 13 is housed in a case (not shown) together with the electric blower fan 26 and is arranged in an instrument panel (not shown) at the front of the compartment 16. Inside the case in which the compartment evaporator 13 and the blower fan 26 are housed, the inside air is introduced from an inside air inlet (not shown), and the outside air is introduced from an outside air inlet (not shown).

  The inside air and outside air are blown to the vehicle interior evaporator 13 by the blower fan 26 and cooled, and then blown out into the vehicle interior 16 as shown by an arrow C from an air outlet (not shown).

  Of the two evaporators 13 and 14, the other freezer evaporator 14 is a cooling heat exchanger that cools the air by absorbing and evaporating the low-temperature and low-pressure refrigerant flowing out of the expansion valve 25 from the air, The space in the freezer 17 is cooled.

  This freezer evaporator 14 is housed in a case (not shown) together with an electric blower fan 27 and is disposed on the vehicle front side of the freezer 17. In the case where the freezer evaporator 14 and the electric blower fan 27 are housed, the air in the freezer 17 is introduced through an air passage (not shown).

  The introduced air is blown to the freezer evaporator 14 by the blower fan 27 to be cooled, and blown into the freezer 17 as shown by an arrow D from a blower outlet (not shown).

  Incidentally, in the refrigeration cycle 10, an electromagnetic valve 28 is disposed on the upstream side of the refrigerant flow of the expansion valve 24, and an electromagnetic valve 29 is disposed on the downstream side of the refrigerant flow of the vehicle interior evaporator 13. By opening and closing the electromagnetic valves 28 and 29, the refrigerant flow in the vehicle interior evaporator 13 can be interrupted.

  Similarly, an electromagnetic valve 30 is disposed on the upstream side of the refrigerant flow of the expansion valve 25, and an electromagnetic valve 31 is disposed on the downstream side of the refrigerant flow of the freezer evaporator 14. By opening and closing the electromagnetic valves 30 and 31, the refrigerant flow in the freezer evaporator 14 can be interrupted. Further, a check valve 32 is arranged on the downstream side of the refrigerant flow of the electromagnetic valve 31, and the check valve 32 prevents the refrigerant from flowing back to the freezer evaporator 14.

  Next, an outline of the electric control unit in the present embodiment will be described. The electronic control device 33 is constituted by a known microcomputer comprising a CPU, ROM, RAM, etc. and its peripheral circuits. The electronic control device 33 corresponds to the control device in the present invention.

  Detection signals are input to the electronic control device 33 from a vehicle speed sensor 34 that detects the vehicle traveling speed V and a condenser front surface temperature sensor 35 that detects the condenser front surface temperature Ta. Here, the condenser front surface temperature Ta is the air temperature on the front surface side of the condenser 12, that is, on the vehicle front side of the condenser 12.

  In this example, the vehicle speed sensor 34 is disposed on the front wheel portion of the vehicle, and the condenser front surface temperature sensor 35 is disposed on the front portion of the condenser 12.

  Further, an air conditioning operation panel (not shown) disposed around the instrument panel in the passenger compartment 16 is provided with a refrigeration switch 36 and an air conditioner switch 37 that are manually operated by a passenger. The operation signal is also input to the electronic control unit 33.

  Here, the refrigeration switch 36 and the air conditioner switch 37 generate an on / off signal for the operation of the compressor 11 of the refrigeration cycle 10, and the compressor 11 is turned on when any one of the refrigeration switch 36 and the air conditioner switch 37 is turned on. Is turned on, and the refrigerant circulates in the refrigeration cycle 10.

  The applied voltage of the electric motor 22 of the cooling fan 21 of the condenser 12 is intermittently interrupted by the motor drive circuit 38, and the rotation of the cooling fan 21 is intermittently performed. Further, the motor driving circuit 38 reverses the polarity of the voltage applied to the electric motor 22, whereby the cooling fan 21 can be rotated in the reverse direction.

  Further, power is supplied to the electronic control unit 33 from an in-vehicle battery (not shown) via an ignition switch (not shown) of the traveling engine 20.

  Next, the overall operation of the vehicle air conditioner in the above configuration will be described. First, the operation of the refrigeration cycle 10 will be described. In this example, there are three operation modes of the refrigeration cycle 10: a freezer single operation mode, a vehicle interior single operation mode, and a vehicle interior / freezer simultaneous operation mode.

  When only the refrigeration switch 36 of the refrigeration switch 36 and the air conditioner switch 37 of the air conditioning operation panel is turned on in a state where the ignition switch of the traveling engine 20 is turned on and power is supplied to the electronic control unit 33, the freezer single operation is performed. It becomes a mode.

  In this freezer independent operation mode, the solenoid valves 28 and 29 are closed and the solenoid valves 30 and 31 are opened. As a result, the refrigerant flow in the compartment evaporator 13 is cut off, and the entire amount of refrigerant circulating in the refrigeration cycle 10 flows through the freezer evaporator 14, so that the interior of the compartment 16 is not cooled and only in the freezer 17. Is cooled.

  In addition, when only the air conditioner switch 37 of the refrigeration switch 36 and the air conditioner switch 37 on the air conditioning operation panel is turned on, the vehicle interior single operation mode is set. In this vehicle interior independent operation mode, the solenoid valves 28 and 29 are opened, and the solenoid valves 30 and 31 are closed. As a result, the refrigerant flow in the freezer evaporator 14 is blocked, and the entire amount of refrigerant circulating in the refrigeration cycle 10 flows in the vehicle interior evaporator 13, so that the interior of the freezer 17 is not cooled, but only in the vehicle interior 16. Is cooled.

  Further, when both the refrigeration switch 36 and the air conditioner switch 37 on the air conditioning operation panel are turned on, the vehicle interior / freezer simultaneous operation mode is set. In this vehicle interior / freezer simultaneous operation mode, the solenoid valves 30 and 31 are always opened, and the solenoid valves 28 and 29 are repeatedly opened and closed periodically.

  In this example, the solenoid valves 28 and 29 are repeatedly opened for 5 seconds and then closed for 10 seconds. As a result, the refrigerant can flow through both the compartment evaporator 13 and the freezer evaporator 14, and also flows through the freezer evaporator 14 as compared to the refrigerant flow rate flowing through the compartment evaporator 13. The refrigerant flow rate can be increased.

  For this reason, since the evaporation pressure of the freezer evaporator 14 can be made lower than the evaporation pressure of the vehicle interior evaporator 13, the interior of the vehicle interior 16 and the interior of the freezer 17 can be cooled and cooled simultaneously, and The inside of the freezer 17 can be cooled to a lower temperature than in the passenger compartment 16.

  By the way, when the evaporation pressure of the freezer evaporator 14 becomes lower than the evaporation pressure of the compartment evaporator 13, the refrigerant that flows out of the compartment evaporator 13 and flows toward the compressor 11 flows to the freezer evaporator 14. Try to backflow. Therefore, in this example, since the check valve 32 is disposed on the downstream side of the refrigerant flow of the electromagnetic valve 31, the reverse flow of the refrigerant to the freezer evaporator 14 can be prevented.

  Next, the operation of the vehicular outdoor heat exchanger cooling device according to the present embodiment will be described. The flowchart of FIG. 3 shows an outline of control processing executed by the microcomputer of the electronic control unit 33.

  In the control routine of FIG. 3, any one of the refrigeration switch 36 and the air conditioner switch 37 of the air conditioning operation panel is turned on in a state where the ignition switch of the traveling engine 20 is turned on and power is supplied to the electronic control unit 33. And start.

  First, after initialization of flags, timers, etc., detection signals from the vehicle speed sensor 34 and the condenser front surface temperature sensor 35 are read in step S100.

  Subsequently, in step S110, based on the vehicle travel speed V detected by the vehicle speed sensor 34, it is determined whether or not the vehicle 15 is stopped (V = 0), and when the vehicle 15 is stopped, Proceed to the next Step S120.

  In step S120, the electronic control unit 33 controls the motor drive circuit 38 to rotate the cooling fan 21 in the reverse direction. Thereby, as indicated by arrow B, air is blown to the condenser 12 from the rear of the vehicle toward the front of the vehicle.

  Thereby, when the vehicle is stopped, the condenser 12 can suck the air on the rear side of the vehicle, and can avoid sucking the high-temperature air heated by the exhaust heat of the traveling engine 20. As a result, it is possible to avoid a decrease in the cooling capacity of the condenser 12 due to the exhaust heat of the traveling engine 20.

  On the other hand, when it is determined in step S110 that the vehicle 15 is not stopped (V> 0), the process proceeds to step S130. In step S130, based on the condenser front surface temperature Ta detected by the condenser front surface temperature sensor 35, it is determined whether or not the condenser front surface temperature Ta is equal to or higher than a predetermined temperature.

  As a result, when the condenser front surface temperature Ta is equal to or higher than the predetermined temperature, the process proceeds to step S120. In this example, when the predetermined temperature is 60 ° C. and the condenser front surface temperature Ta is 60 ° C. or higher, the process proceeds to step S120.

  And since the cooling fan 21 is reversely rotated in step S120, air is sent to the condenser 12 from the vehicle rear toward the vehicle front as shown by an arrow B.

  Thereby, not only when the vehicle is stopped but also when the vehicle speed is low, the condenser 12 can suck the air on the rear side of the vehicle, and can avoid sucking the high-temperature air heated by the exhaust heat of the traveling engine 20. As a result, it is possible to avoid a decrease in the cooling capacity of the condenser 12 due to the exhaust heat of the traveling engine 20.

  On the other hand, when it determines with the condenser front surface temperature Ta not being more than predetermined temperature in step S130, it progresses to step S140. In step S140, the electronic control unit 33 controls the motor drive circuit 38 to rotate the cooling fan 21 forward.

  When the cooling fan 21 is rotated forward, the blown air flows from the front of the vehicle to the rear of the vehicle as indicated by an arrow A, so that the air heated by the exhaust heat of the traveling engine 20 enters the condenser 12 as indicated by an arrow E. Sucked.

  However, the condenser front surface temperature Ta is not equal to or higher than the predetermined temperature, in other words, the high-temperature air heated by the engine exhaust heat is cooled by the traveling wind, so the cooling capacity of the condenser 12 does not decrease.

  When the cooling fan 21 is rotated forward, the flow direction A of the blown air becomes substantially the same as the flow direction F of the traveling wind. For this reason, the air blown by the cooling fan 21 can be blown to the condenser 12 without facing the running wind F when the vehicle travels. As a result, the cooling capacity of the condenser 12 can be ensured even when the vehicle is traveling.

(Other embodiments)
In the above embodiment, the predetermined temperature of the condenser front surface temperature Ta in step S130 is 60 ° C., but is not limited to this. That is, the predetermined temperature may be set as appropriate in consideration of the correlation between the condenser front surface temperature Ta and the cooling capacity of the condenser 12.

  Moreover, in the said embodiment, although the condenser 12 is arrange | positioned in the vehicle rearmost part, the position of the condenser 12 in a vehicle front-back direction is not limited to this, It can change suitably.

  Moreover, in the said embodiment, although the cooling fan 21 is arrange | positioned in the vehicle rear side of the condenser 12, you may arrange | position the cooling fan 21 in the vehicle front side of the condenser 12. FIG.

  Moreover, in the said embodiment, although the condenser 12 which cools and condenses a refrigerant | coolant is used as an outdoor heat exchanger, the heat exchanger in a supercritical cycle, ie, a refrigerant | coolant, remains in a supercritical state as an outdoor heat exchanger. A radiator that only cools and does not condense may be used.

  Moreover, the refrigeration cycle to which the present invention is applied is not limited to the above embodiment, and can be applied to various refrigeration cycles having an outdoor heat exchanger. For example, the compartment evaporator 13 may be eliminated and only the freezer 17 may be cooled only by the freezer evaporator 14. Alternatively, the freezer evaporator 14 may be eliminated, and only the interior of the passenger compartment 16 may be cooled only by the passenger compartment evaporator 13.

  Moreover, in the said embodiment, although this invention is applied to the refrigerator car, it is not limited to this, It is applicable to the various vehicles which arrange | position an outdoor heat exchanger under a vehicle floor.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole block diagram of the vehicle air conditioner to which the vehicle outdoor heat exchanger cooling device by 1st Embodiment of this invention is applied. It is a schematic sectional drawing of the vehicle carrying the vehicle air conditioner of FIG. It is a flowchart which shows the outline | summary of the action | operation of 1st Embodiment of this invention. It is a schematic sectional drawing of the vehicle in a prior art.

Explanation of symbols

  12 ... Condenser (outdoor heat exchanger), 20 ... Engine for traveling, 21 ... Cooling fan.

Claims (3)

An outdoor heat exchanger (12) disposed under the vehicle floor for exchanging heat between air and refrigerant;
A cooling fan (21) for blowing the air to the outdoor heat exchanger (12);
During normal operation, the cooling fan (21) is rotated forward to blow the air from the front of the vehicle toward the rear of the vehicle. When the vehicle is stopped, the rotation direction of the cooling fan (21) is reversed to rotate the air. A vehicle outdoor heat exchanger cooling device comprising a control device (33) for blowing air from the rear of the vehicle toward the front of the vehicle. The said control apparatus (33) reversely rotates the rotation direction of the said cooling fan (21) when the condenser front surface temperature (Ta) is more than predetermined temperature in addition to the said vehicle stop. The outdoor heat exchanger cooling device for vehicles as described. The outdoor heat exchanger (12) is disposed on the vehicle rear side of the traveling engine (20) at a position where hot air heated by engine exhaust heat flows. Or the outdoor heat exchanger cooling device for vehicles of 2.

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