US20110073281A1

US20110073281A1 - Heat exchanger for vehicular air conditioning apparatus

Info

Publication number: US20110073281A1
Application number: US12/569,163
Authority: US
Inventors: Takahiro Seto
Original assignee: Keihin Corp
Current assignee: Keihin Corp
Priority date: 2009-09-29
Filing date: 2009-09-29
Publication date: 2011-03-31
Also published as: JP2011073669A; JP5667399B2

Abstract

In an evaporator that constitutes part of a vehicular air conditioning apparatus, a sensor is provided, which is capable of detecting the temperature in the evaporator. In the evaporator, the sensor is installed on a back surface side thereof facing a downstream side, and on a first cooling section, through which air from a first blower unit flows. Also, the sensor is installed at a position in the vicinity of a supply conduit that supplies a coolant medium with respect to the evaporator. At a region where a maximum low temperature in the evaporator occurs, and for which there is a fear of freezing due to moisture contained within the air, the temperature is detected by the sensor.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a heat exchanger, which is installed in a vehicular air conditioning apparatus that performs temperature adjustment of a vehicle compartment, whereby the heat exchanger is used by the vehicular air conditioning apparatus for cooling and heating of air that is blown into the vehicle compartment.
2. Description of the Related Art
In a vehicular air conditioning apparatus that is mounted in a vehicle, internal and external air is drawn into a casing by a blower, and after cooled air, which has been cooled by a heat exchanger that forms a cooling means, and heated air, which has been heated by a heat exchanger that forms a heating means, are mixed together in the casing at a predetermined mixing ratio, the mixed air is blown out from defroster blow-out ports, face blow-out ports, or foot blow-out ports arranged in the vehicle compartment, whereby adjustment of temperature and humidity in the vehicle compartment is carried out.
In a vehicular air conditioning apparatus such as described above, for example, as disclosed in Japanese Laid-Open Patent Publication No. 05-124426, a blower unit having a blower, a cooling unit containing an evaporator, and a heating unit containing a heater core are arranged along a line, wherein such units are divided in half by a plurality of partition plates, which are disposed on a center line thereof. In addition, air that is blown out from the blower flows through one of the passages divided by the partition plates, and after passing through the evaporator and the heater core, is blown out from a first blow-out port, whereas air that flows through the other of the passages divided by the partition plates, in a similar manner, passes through the evaporator and the heater core, and is blown out from another second blow-out port that differs from the first blow-out port.
Notwithstanding, with the vehicular air conditioning apparatus according to the conventional technique, when air that is taken in from an external intake port flows through the evaporator, moisture contained within the air freezes when the moisture comes into contact with the evaporator that forms the cooling means. As a result, the ventilation passageways inside the evaporator become narrowed, and there is a concern that the cooling effectiveness of the evaporator will be deteriorated.

SUMMARY OF THE INVENTION

A general object of the present invention is to provide a heat exchanger for use in a vehicular air conditioning apparatus, which is capable of preventing freezing in the heat exchanger due to moisture becoming frozen and adhering to surfaces of the heat exchanger, in order to obtain stable operating characteristics.
In order to achieve the aforementioned object, the present invention is characterized by a heat exchanger in a vehicular air conditioning apparatus having a casing including a first passage through which external air flows and a second passage through which internal air flows, and a switching mechanism for switching a flow state of the external air and the internal air in the first passage and the second passage, wherein the heat exchanger is disposed in the interior of the casing so as to straddle between the first passage and the second passage, for thereby cooling and supplying the external air and the internal air, the heat exchanger comprising:
a supply member, which is supplied with a coolant medium that circulates through the interior thereof;
a discharge member, through which the coolant medium that has circulated through the interior is discharged;
a first cooling section, which faces the first passage, for performing cooling of the external air that flows through the first passage;
a second cooling section, which faces the second passage, for performing cooling of the internal air that flows through the second passage; and
a sensor for detecting a temperature of the heat exchanger,
wherein the sensor faces toward the first cooling section, and is disposed at a position proximate to the supply member.
The above and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external perspective view of a vehicular air conditioning apparatus according to an embodiment of the present invention;

FIG. 2 is an overall cross sectional view of the vehicular air conditioning apparatus shown in FIG. 1;

FIG. 3 is a cross sectional perspective view taken along line of FIG. 1;

FIG. 4 is an external perspective view of an evaporator shown in FIG. 2;

FIG. 5 is a plan view of the evaporator shown in FIG. 4;

FIG. 6 is an outline view showing the flow of a coolant medium in the evaporator of FIG. 4;

FIG. 7 is an outline structural view showing a casing, first and second blower units, and an evaporator, which constitute the vehicular air conditioning apparatus of FIG. 1; and

FIG. 8 is an external perspective view showing a modified example of the evaporator shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment concerning a heat exchanger for use in a vehicular air conditioning apparatus according to the present invention shall be explained in detail below with reference to the accompanying drawings. In FIG. 1, reference numeral 10 indicates a vehicular air conditioning apparatus according to an embodiment of the present invention. The vehicular air conditioning apparatus 10, for example, is installed in a vehicle having three rows of seats arranged along the direction of travel of the vehicle. In the following descriptions, the first row of seats in the vehicle compartment of the vehicle is designated as front seats, the second row of seats is designated as middle seats, and the third row of seats is designated as rear seats.
Further, the vehicular air conditioning apparatus 10 is installed so that the right-hand side thereof shown in FIG. 2 (in the direction of arrow A) is oriented toward the front side of the vehicle, whereas the left-hand side (in the direction of arrow B) is oriented toward the rear side of the vehicle. The arrow A direction shall be described as a forward direction, whereas the arrow B direction shall be described as a rearward direction.
In the present embodiment, inside a casing 12, plural rotating members made up of dampers or the like are provided, wherein the rotating members are operated by rotational drive sources such as motors or the like. For purposes of simplification, depictions and explanations concerning such rotational drive sources have been omitted.
As shown in FIGS. 1 through 3, the vehicular air conditioning apparatus 10 includes the casing 12 constituted by respective air passages, a first blower unit 16 connected through a connection duct 14 to a side portion of the casing 12 for taking in air (external and internal air) from outside of the vehicle and from inside the vehicle compartment, and blowing the air toward the front seat side of the vehicle, an evaporator (heat exchanger) 18 arranged inside the casing 12 for cooling air, a heater core 20 for heating air, a second blower unit 22 connected to a lower portion of the casing 12 for taking in air from inside the vehicle compartment (interior air) and blowing the air toward the rear seats of the vehicle, and a damper mechanism (switching mechanism) 24 for switching the flow of air that flows through and inside each of the respective passages.
The casing 12 is constituted by first and second divided casings 26, 28 having substantially symmetrical shapes, wherein a center plate 30 is disposed between the first divided casing 26 and the second divided casing 28. The connection duct 14 is connected on a lower side portion of the first divided casing 26, and a first intake port 32 is formed through which air is supplied from the first blower unit 16. The first intake port 32 communicates with a first front passage (first passage) 34 disposed on an upstream side of the evaporator 18.
The evaporator 18 is disposed so as to straddle between the first divided casing 26 and the second divided casing 28. One end of the evaporator 18 in the forward direction (the direction of arrow A) of the vehicle is inclined downward at a predetermined angle with respect to the other end thereof in the rearward direction of the vehicle.
As shown in FIGS. 4 and 5, in the evaporator 18, for example, a pair of tubes (first and second tubes) 36 a, 36 b are formed from thin plates of aluminum or the like, and fins 38, which are folded in a serpentine-like undulating (wavy) shape, are disposed respectively between the stacked tubes 36 a, 36 b. On the fins 38, a plurality of louvers (not shown) are formed, which are cut out so as to be inclined at predetermined angles with respect to the planar surface of the fins 38. By causing a coolant medium L (see FIG. 6) to flow through the interior of the tubes 36 a, 36 b, air that passes through the louvers and flows between the fins 38 is cooled by the coolant medium L and is supplied to the downstream side as chilled air.
Further, on opposite ends of the tubes 36 a, 36 b in the evaporator 18, respective hollow first and second tank portions 40 a, 40 b are connected for retaining a coolant medium L that flows through the interior of the tubes 36 a, 36 b. Together therewith, thin plate shaped retaining plates 42 a, 42 b are disposed respectively on opposite ends of the first and second tank portions 40 a, 40 b. The retaining plates 42 a, 42 b are in parallel with the tubes 36 a, 36 b.
In addition, on the side of the first tank portion 40 a, a supply conduit (supply member) 46 through which the coolant medium L is supplied from the exterior, and a discharge conduit (discharge member) 48 through which the coolant medium L having circulated through the interior of the evaporator 18, are connected (see FIG. 4). The supply conduit 46 is formed somewhat smaller in diameter than the discharge conduit 48.
The supply conduit 46 and the discharge conduit 48 are disposed in parallel in the thickness direction of the evaporator 18, such that when the evaporator 18 is arranged inside the casing 12, the discharge conduit 48 is disposed on a front surface 18 a that faces the first front passage 34 on the upstream side, whereas the supply conduit 46 is disposed on a back surface (side surface) 18 b facing second front passages 80 a, 80 b on the downstream side of the evaporator 18.
More specifically, the evaporator 18 is disposed such that the front surface 18 a thereof is on the upstream side inside the casing 12, whereas the back surface 18 b is disposed on the downstream side (see FIG. 2).
Furthermore, the evaporator 18 includes a first cooling section 50 disposed on one end side having the first tank portion 40 a, and which faces toward the first front passage 34 in the interior of the casing 12, and a second cooling section 52 disposed on the other end side having the second tank portion 40 b, and which faces toward a later-described first rear passage (second passage) 130 in the interior of the casing 12 (see FIG. 2). The first cooling section 50 is arranged forwardly (in the direction of arrow A) in the casing 12 and cools air supplied from the first blower unit 16 to the first front passage 34, whereas the second cooling section 52 is arranged rearwardly (in the direction of arrow B) of the casing 12 and cools air supplied from the second blower unit 22 to the first rear passage 130.
Further, a dividing means (not shown) for blocking communication of air between the first cooling section 50 and the second cooling section 52 is disposed at a boundary portion C between the first cooling section 50 and the second cooling section 52 in the evaporator 18. The dividing means, for example, may comprise a partition plate which is capable of dividing the interior of the evaporator 18 into two parts, or a partition member which is capable of being installed from the exterior of the evaporator 18.
A circulation path of the coolant medium L in the evaporator 18 shall briefly be described with reference to FIG. 6. Herein, the direction from one end side of the first tank portion 40 a on which the supply conduit 46 and the discharge conduit 48 are disposed to the other end side shall be described as a rearward direction (the direction of arrow D1), whereas the direction from the other end side of the first tank portion 40 a to the one end side shall be described as a forward direction (the direction of arrow D2).
First, the coolant medium L, which is introduced from the supply conduit 46, flows downwardly (in the direction of arrow E1) from the first tank portion 40 a through the tubes 36 b on the back surface 18 b in the evaporator 18. At this time, in the interior of the first tank portion 40 a, since first guide walls 54 in parallel with the retaining plates 42 a, 42 b are disposed therein, the coolant medium L is guided downwardly through the tubes 36 b by the first guide walls 54, without flowing in the rearward direction (the direction of arrow D1) beyond the first guide walls 54. In addition, the coolant medium L, which has reached the second tank portion 40 b disposed downwardly therefrom, flows in the rearward direction along the second tank portion 40 b, is guided to the tubes 36 b by second guide walls 56 in parallel with the retaining plates 42 a, 42 b, and then is guided upwardly (in the direction of arrow E2) through the tubes 36 b.
Next, the coolant medium L, which has flowed upwardly, then flows rearwardly (in the direction of arrow D1) in the evaporator 18 inside the first tank portion 40 a. Then, after flowing downwardly (in the direction of arrow E1) through the tubes 36 b and being guided into the second tank portion 40 b, flows to the front surface 18 a side of the evaporator 18. Further, after passing through the tubes 36 a disposed on the front surface 18 a side of the evaporator 18 and flowing upwardly (in the direction of arrow E2), the coolant medium L flows toward the forward side (in the direction of arrow D2) inside the first tank portion 40 a and once again flows downwardly (in the direction of arrow E1) through the tubes 36 a. Since the coolant medium L is prevented from flowing in the forward direction (the direction of arrow D2) by the first guide walls 54, the coolant medium L is guided downwardly (in the direction of arrow E1) by the first guide walls 54 without flowing toward the forward side beyond the first guide walls 54.
Lastly, the coolant medium L, which has been guided downwardly into the second tank portion 40 b, after having flowed to the forward side (in the direction of arrow D2) and then upwardly along the tubes 36 a, reaches the first tank portion 40 a and is discharged from the discharge conduit 48.
In this manner, the coolant medium L, which has been guided from the supply conduit 46 to the interior of the evaporator 18, and after having flowed mutually up and down in the rearward direction (the direction of arrow D1) on the back surface 18 b side, is circulated toward the front surface 18 a side, flows mutually up and down in the forward direction (the direction of arrow D2), whereupon the coolant medium L is discharged from the discharge conduit 48. At this time, air supplied from the upstream side into the evaporator 18 is cooled effectively by the coolant medium L that flows through the tubes 36 a, 36 b and by passing over the fins 38, and the cooled air then flows toward the downstream side.
As shown in FIG. 5, on the evaporator 18 in which the coolant medium L is circulated, a sensor 58 is disposed for detecting the surface temperature of the evaporator 18. The sensor 58 is constituted from a main body portion 60 for detecting temperature, which is attached to the evaporator 18, and a cable 62 that is connected to the main body portion 60. Additionally, the sensor 58 is connected via the cable 62 to a non-illustrated controller, whereby the surface temperature of the evaporator 18 detected by the sensor 58 is output as a detection signal to the controller.
The sensor 58, for example, is installed at a region S1 where the temperature is lowest, and where there is a fear that generation of freezing due to adhered moisture will occur, and serves to detect the surface temperature in the evaporator 18. Stated otherwise, by continuously detecting the surface temperature on the evaporator 18, the sensor 58 is provided with the object of avoiding generation of freezing caused by the adherence of moisture on the evaporator 18 when moisture-containing air passes through the evaporator 18.
Accordingly, the sensor 58, for example, is arranged within the region S1 on the back surface 18 b side of the evaporator 18 which is supplied with a low temperature coolant medium L from the supply conduit 46, and further, which is in the vicinity of the supply conduit 46. In addition, the region S1 is on the side of the first cooling section 50 that faces toward the first front passage 34 and the second front passages 80 a, 80 b, to which air containing a comparatively large amount of moisture is supplied from the first blower unit 16. The region S1, for example, is a region surrounded by an imaginary line F drawn in a perpendicular direction to the lengthwise direction of the first tank portion 40 a at a position where the first guide walls 54 in the first tank portion 40 a constituting the evaporator 18 are disposed, and the boundary portion C between the first cooling section 50 and the second cooling section 52, and is an area on the side of the supply conduit 46.
More specifically, in the evaporator 18, a position in the vicinity of the supply conduit 46 on the back surface 18 b side in the first cooling section 50 forms a position of maximum low temperature caused by the coolant medium L, as well as a region where high humidity air, containing a large amount of moisture therein, flows. Therefore, the position is a region S1 where freezing easily occurs, and at which detection of temperature by the sensor 58 is required.
Stated otherwise, for example, on the back surface 18 b side of the evaporator 18, the coolant medium L, which has undergone heat exchange in the evaporator 18 and is raised in temperature, flows through a region S2 that lies outside of the region S1 where the sensor 58 is disposed, and in the second cooling section 52 only air (internal air) from inside the vehicle compartment, for which the contained amount of moisture therein is low in comparison with the air supplied from the first blower unit 16, is supplied from the second blower unit 22. Owing thereto, at the region S2, since the temperature of the coolant medium L is comparatively high, and further, the possibility of moisture becoming adhered thereto is low, the likelihood of freezing in the evaporator is low.
Further, as understood from the circulation path of the coolant medium L, which is shown in FIG. 6, because the front surface 18 a side of the evaporator 18 is constructed such that the coolant medium L, which has flowed through the back surface 18 b of the evaporator 18 and has undergone heat exchange, then flows through the front surface 18 a, the possibility of the front surface 18 a side undergoing freezing (i.e., developing frost thereon) is lowered, due to the coolant medium L having been raised in temperature.
On the other hand, as shown in FIGS. 1 to 3, on the downstream side of the evaporator 18, second front passages 80 a, 80 b are formed, through which air having passed through the first cooling section 50 is supplied. Upwardly of the second front passages 80 a, 80 b, a third front passage 82 and a fourth front passage 84 are formed in a branching or bifurcated manner. Further, in the second front passages 80 a, 80 b, a first air mixing damper 86 is rotatably disposed so as to face toward the branching portion of the third front passage 82 and the fourth front passage 84.
Additionally, by rotation of the first air mixing damper 86, the blowing condition and blowing rate of cooled air that has passed through the evaporator 18 into the third front passage 82 and the fourth front passage 84 is adjusted. The third front passage 82 is arranged on the forward side (in the direction of arrow A), whereas the fourth front passage 84 is arranged on the rearward side (in the direction of arrow B) of the casing 12. The heater core 20 is disposed on a downstream side of the fourth front passage 84.
Further, on the forward side (in the direction of arrow A) of the third front passage 82, a bypass passage 88 is formed, which extends along the third front passage 82 and supplies air to a later-described mixing section 98 from the downstream side of the evaporator 18, and a bypass damper 90 is disposed on a downstream side of the bypass passage 88. The bypass passage 88 is provided to supply cool air cooled by the evaporator 18 directly to the downstream side under a switching action of the bypass damper 90.
The heater core 20, similar to the evaporator 18, is disposed so as to straddle between the first divided casing 26 and the second divided casing 28. One end of the heater core 20 in the forward direction (the direction of arrow A) of the vehicle is inclined downward at a predetermined angle with respect to the other end thereof in the rearward direction (the direction of arrow B) of the vehicle. The heater core 20 includes a first heating section 92, which faces the fourth front passage 84 and heats air supplied from the fourth front passage 84, and a second heating section 94, which faces the later described third rear passage 148 and heats air supplied from the third rear passage 148.
On the downstream side of the heater core 20, a fifth front passage 96 is formed. The fifth front passage 96 extends in the forward direction, and at a location that merges with the downstream side of the third front passage 82, the mixing section 98 is formed, in which cooled air supplied through the third front passage 82 and warm air supplied through the fifth front passage 96 are mixed. A defroster blow-out port 100 opens upwardly of the mixing section 98, and to the side of the mixing section 98, a rearwardly extending sixth front passage 102 is formed.
Further, in the mixing section 98, a defroster damper 104 is rotatably disposed, facing the defroster blow-out port 100. By rotation of the defroster damper 104, the blowing state of air into the defroster blow-out port 100 and the sixth front passage 102 is switched, and the blowing rate thereof is adjusted.
In the sixth front passage 102, a first vent blow-out port 106 opens upwardly, and a vent damper 108 is rotatably disposed facing toward the first vent blow-out port 106, and communicating with a seventh front passage 110, which extends further rearwardly. By rotation of the vent damper 108, the blowing state of air from the mixing section 98 is switched to the first vent blow-out port 106 and the seventh front passage 110, and further, the blowing rate of the air is capable of being adjusted.
The defroster blow-out port 100 and the first vent blow-out port 106 open respectively upwardly of the casing 12. The defroster blow-out port 100 is arranged on a forward side (in the direction of arrow A), whereas the first vent blow-out port 106 is arranged on the rearward side (in the direction of arrow B), substantially centrally in the casing 12 with respect to the defroster blow-out port 100.
On a downstream side of the seventh front passage 110, a first heat passage 112 is connected, which extends in the widthwise direction of the casing 12 and blows air through a non-illustrated first heat blow-out port in the vicinity of the feet of passengers in the front seats in the vehicle compartment. Together therewith, a second heat passage 114 is connected, which extends rearwardly of the casing 12 and blows air through a second heat blow-out port (not shown) in the vicinity of the feet of passengers in the middle seats inside the vehicle compartment.
The first blower unit 16 includes an intake damper 118 in which a duct 116 for introducing external air is disposed in an inlet opening thereof, for carrying out switching of internal and external air, and a first blower fan 120 for supplying to the interior of the casing 12 air (external air or internal air) that is taken in from the duct 116 or the like. A blower case 122 in which the first blower fan 120 is accommodated communicates with the interior of the casing 12 via the connection duct 14 connected to the first intake port 32. The rotation of the first blower fan 120 is controlled by a first blower motor 121, which is driven by supplying electrical power thereto.
In this manner, air supplied from the first blower unit 16 is introduced to the interior of the casing 12 through the connection duct 14 and the first intake port 32, and by rotating actions of the first air mixing damper 86, the defroster damper 104, the vent damper 108 and the bypass damper 90, which collectively make up the damper mechanism 24, air is selectively supplied through the first through seventh front passages 74, 80 a, 80 b, 82, 84, 96, 102, 110, and the bypass passage 88 into the defroster blow-out port 100, the first vent blow-out port 106 and the first and second heat passages 112, 114, which are capable of blowing air to the front and middle seats in the vehicle.
On the other hand, on a lower portion of the casing 12, a second intake port 128 through which air is supplied from the second blower unit 22 is formed on a rearward side (in the direction of arrow B) perpendicular to the first intake port 32. The second intake port 128 opens at a position on an upstream side of the evaporator 18 and communicates with the first rear passage 130.
The first rear passage 130 is separated from the first front passage 34 by a first dividing wall 132, and a rotatable ventilation-switching damper (switching damper) 136 is provided between a communication opening 134 formed in the first dividing wall 132 and the second intake port 128. In addition, in the case that a mode is selected in which blowing of air from the second blower unit 22 is halted and blowing of air only from the first blower unit 16 is carried out, by blocking the second intake port 128 by the ventilation-switching damper 136 (i.e., the state shown by the two-dot-dash line in FIG. 2), back flowing of air into the second blower unit 22 can be prevented when a portion of the air supplied from the first blower unit 16 passes through the interior of the evaporator 18 and the heater core 20 and is leaked out to the side of the first through fourth rear passages 130, 142 a, 142 b, 148, 150. Thus, noise generated by the second blower unit 22 due to the back flowing of air is prevented. Also, the air that has reached the second blower unit 22, i.e., unnecessary air, is prevented from flowing into the vehicle compartment, and an unpleasant sensation is prevented from being imparted to passengers in the vehicle.
In this case, as shown in FIG. 7, by rotating the ventilation-switching damper 136 to the side of the second intake port 128 and opening the communication opening 134, a portion of the air supplied to the first front passage 34 can be supplied to the side of the first rear passage 130. The driving and controlling of the ventilation-switching damper 136 will be described later.
The second blower unit 22 includes a second blower fan 138 that takes in air (internal air) from the vehicle compartment and supplies the intake air to the interior of the casing 12. A blower case 140 in which the second blower fan 138 is accommodated is connected to the second intake port 128 of the casing 12 and communicates with the first rear passage 130. The second blower fan 138, similar to the first blower fan 120, is controlled by a second blower motor 141, which is driven by supplying electrical power thereto.
On a downstream side of the first rear passage 130, second rear passages 142 a, 142 b are formed to which air that has passed through the second cooling section 52 of the evaporator 18 is supplied. The second rear passages 142 a, 142 b are separated from the second front passages 80 a, 80 b by a second dividing wall 144, and the second dividing wall 144 extends to the evaporator 18. Owing thereto, on a downstream side of the evaporator 18, air that has passed through the first rear passage 130 and flows to the second cooling section 52 of the evaporator 18 does not intermix mutually with air that has passed through the first front passage 34 and flows to the first cooling section 50 of the evaporator 18.
Herein, as shown in FIG. 3, the second rear passages 142 a, 142 b, the second front passages 80 a, 80 b and the first vent blow-out port 106 are separated respectively on sides of the first and second divided casings 26, 28 about the center plate 30, which is disposed in the center of the casing 12, thereby forming the second rear passage 142 a and the second rear passage 142 b, the second front passage 80 a and the second front passage 80 b, and the first vent blow-out port 106 a and the first vent blow-out port 106 b. Furthermore, as shown in FIG. 4, a pair of communication switching dampers 146 a, 146 b, which are capable of switching a communication state between the second rear passage 142 a and the second front passage 80 a, and between the second rear passage 142 b and the second front passage 80 b, are disposed in the second rear passage 142 a and the second rear passage 142 b, respectively, wherein one of the communication switching dampers 146 a and the other of the communication switching dampers 146 b are rotatably controlled separately and independently from each other.
In addition, by rotation of the pair of communication switching dampers 146 a, 146 b, the second rear passages 142 a, 142 b for blowing air to the middle seats and rear seats in the vehicle compartment are placed in communication mutually with the second front passages 80 a, 80 b for blowing air to the front seats in the vehicle compartment. For example, by changing the rotation amount of one of the communication switching dampers 146 a and the rotation amount of the other communication switching damper 146 b, respectively, the blowing rate of air that is blown from the first vent blow-out port 106 a through the second front passage 80 a to the passenger's side in the front seats, and the blowing rate and temperature of air that is blown from the first vent blow-out port 106 b through the second front passage 80 b to the driver's side in the front seats, can be controlled separately from each other.
The third rear passage 148 facing the heater core 20 is formed on the downstream side of the second rear passages 142 a, 142 b. One side of the third rear passage 148 opens into the heater core 20, whereas another side thereof opens onto the side of an adjacent fourth rear passage 150. In addition, a second air mixing damper 152, which mixes at a predetermined mixing ratio the cool air and warm air supplied to the third rear passage 148, thereby producing mixed air, is disposed rotatably in the third rear passage 148. The second air mixing damper 152 switches the communication state between the third rear passage 148 and the upstream or downstream side of the fourth rear passage 150, which is connected to the downstream side of the heater core 20. Consequently, air cooled by the evaporator 18 and supplied to the third rear passage 148, and air heated by the heater core 20 and that flows to the fourth rear passage 150, are mixed at a predetermined mixing ratio inside the fourth rear passage 150 by rotation of the second air mixing damper 152, and are blown out therefrom. Specifically, an intermediate location of the fourth rear passage 150 functions as a mixing section, for mixing cool air and warm air that is blown to the middle seats and rear seats in the vehicle.
The fourth rear passage 150 bends so as to circumvent the other end of the heater core 20 and extends to communicate with fifth and sixth rear passages 154, 156, which branch on a downstream side thereof. A rotatable mode switching damper 158 is disposed at the branching location of the fifth and sixth rear passages 154, 156. The communication state between the fourth rear passage 150 and the fifth and sixth rear passages 154, 156 is switched by rotation of the mode switching damper 158.
The fifth and sixth rear passages 154, 156 extend respectively in the rearward direction (the direction of arrow B) of the vehicle. The fifth rear passage 154 communicates with a second vent blowout port (not shown) for blowing air in the vicinity of the faces of passengers in the middle seats in the vehicle. On the other hand, the sixth rear passage 156 communicates with third and fourth heat blow-out ports (not shown) for blowing air in the vicinity of the feet of passengers in the middle and rear seats.
More specifically, air supplied from the second blower unit 22 is introduced to the interior of the casing 12 through the second intake port 128, and under rotating actions of the second air mixing damper 152 and the mode switching damper 158, which make up the damper mechanism 24, the air passes through the first through sixth rear passages 130, 142 a, 142 b, 148, 150, 154, 156 and is supplied selectively to the second vent blow-out port, and the third and fourth heat blow-out ports (not shown), which are capable of blowing air to the middle and rear seats in the vehicle.
The aforementioned second through sixth front passages 80 a, 80 b, 82, 84, 96, 102, the bypass passage 88 and the second rear passages 142 a, 142 b are disposed respectively so as to straddle between the first divided casing 26 and the second divided casing 28. However, these passages also are divided by the center plate 30, which is disposed in the center of the casing 12.
The vehicular air conditioning apparatus 10 to which the heat exchanger according to the embodiment of the present invention is applied is basically constructed as described above. Next, operations and effects of the invention shall be explained.
First, when operation of the vehicular air conditioning apparatus 10 is started, the first blower fan 120 of the first blower unit 16 is rotated by supplying electrical power thereto, and air (interior or exterior air) that is taken in through the duct 116 or the like is supplied to the first front passage 34 of the casing 12 through the connection duct 14. Simultaneously, air (interior air), which is taken in by rotation of the second blower fan 138 of the second blower unit 22 by supplying electrical power thereto, is supplied to the first rear passage 130 from the blower case 140 while passing through the second intake port 128. In the following descriptions, air supplied to the interior of the casing 12 by the first blower fan 120 shall be referred to as “first air,” and air supplied to the interior of the casing 12 by the second blower fan 138 shall be referred to as “second air.”
The first air and the second air supplied to the interior of the casing 12 are each cooled by passing respectively through the first and second cooling sections 76, 78 of the evaporator 18, and flow respectively as chilled air to the second front passages 80 a, 80 b and the second rear passages 142 a, 142 b, in which the first and second air mixing dampers 86, 152 are disposed.
In the case that a vent mode, for example, is selected by a passenger for blowing air in the vicinity of the faces of passengers, the first air mixing damper 86 is rotated to an intermediate position between the third front passage 82 and the fourth front passage 84, whereupon the first air (cooled air) supplied to the third front passage 82 flows into the mixing section 98, and the first air supplied to the fourth front passage 84 is heated by passing through the heater core 20 to become heated air, and flows into the mixing section 98 through the fifth front passage 96, whereby the first cooled air and the first heated air are mixed together.
The first air (mixed air), which is made up of the cool air and heated air mixed in the mixing section 98, passes through the sixth front passage 102 and is blown in the vicinity of the faces of passengers in the front seats in the vehicle compartment from the first vent blow-out port 106, due to the fact that the defroster blow-out port 100 is blocked by the defroster damper 104, and further, the opening of the seventh front passage 110 is blocked by the vent damper 108.
On the other hand, the second air mixing damper 152 is rotated to an intermediate position in the interior of the third rear passage 148, whereupon the second air (cooled air) supplied to the third rear passage 148 is heated by passing through the heater core 20 to become heated air, and flows to the downstream side through the fourth rear passage 150. Together therewith, cooled second air is supplied directly into the fourth rear passage 150 from the opening of the third rear passage 148, is mixed together with the heated second air, and flows to the downstream side. In addition, under a switching action of the mode switching damper 158, the second air (mixed air) passes through the fifth rear passage 154 and is blown in the vicinity of the faces of passengers in the middle seats in the vehicle compartment from the second vent blowout port (not shown).
Next, in the case that a bi-level mode is selected for blowing air in the vicinity of the faces and feet of passengers in the vehicle compartment, the first air mixing damper 86 is rotated somewhat toward the side of the third front passage 82, whereas the vent damper 108 is placed in an intermediate position, rotated somewhat to the side of the first vent blow-out port 106 compared to the case of the vent mode. Additionally, the cooled first air that has passed through the evaporator 18 is supplied directly into the mixing section 98 via the bypass passage 88, is mixed in the mixing section 98 with the first air (mixed air) that is supplied through the third and fifth front passages 82, 96, and is blown in the vicinity of the faces of passengers from the first vent blow-out port 106. Further, a portion of the first air (mixed air), which flows to the sixth front passage 102 from the mixing section 98, passes through the sixth and seventh front passages 102, 110 and is supplied respectively to the first and second heat passages 112, 114, whereby the air is blown in the vicinity of the feet of passengers in the front and middle seats in the vehicle compartment from the first and second heat blow-out ports (not shown).
At the same time, the second air mixing damper 152 is rotated somewhat in a direction away from the heater core 20, and the mode switching damper 158 is rotated from the position closing the sixth rear passage 156 to an intermediate position between the fifth rear passage 154 and the sixth rear passage 156. In addition, as for the second air, heated air heated by the heater core 20 and cooled air, which is supplied to the fourth rear passage 150 through the opening from the third rear passage 148, are mixed together and blown as mixed air from the fifth rear passage 154, through the second vent blow-out port, and in the vicinity of the faces of passengers riding in the middle seats in the vehicle compartment, while also being blown from the sixth rear passage 156, past the third and fourth heat blow-out ports, and in the vicinity of the feet of passengers riding in the middle and rear seats in the vehicle compartment.
Next, in the case that the heat mode is selected for blowing air in the vicinity of the feet of passengers in the vehicle compartment, the first air mixing damper 86 is rotated further to the side of the third front passage 82 compared to the case of the bi-level mode, while the defroster damper 104 and the vent damper 108 are rotated respectively to block the defroster blow-out port 100 and the first vent blow-out port 106. Consequently, the first air (mixed air), which was mixed in the mixing section 98, passes through the sixth and seventh front passages 102, 110 and flows rearwardly to be supplied respectively to the first and second heat passages 112, 114, and is blown in the vicinity of the feet of passengers in the front and middle seats in the vehicle compartment from the non-illustrated first and second heat blow-out ports.
On the other hand, the second air mixing damper 152 is rotated further toward the side of the opening compared to the case of the bi-level mode, and further, the mode switching damper 158 is positioned to block the fifth rear passage 154. Consequently, the second air (mixed air), which is mixed in the fourth rear passage 150, passes from the fourth rear passage 150, through the sixth rear passage 156, and is supplied to the third and forth heat blow-out ports, whereby the air is blown in the vicinity of the feet of passengers in the middle and rear seats in the vehicle compartment.
Next, an explanation shall be made concerning a heat-defroster mode for blowing air in the vicinity of the feet of passengers in the vehicle compartment, as well as for blowing air in the vicinity of a front window for eliminating fog (condensation) from the front window. In the event that the heat-defroster mode is selected, the defroster damper 104 is rotated in a direction to separate from the defroster blow-out port 100, so as to assume an intermediate position between the defroster blow-out port 100 and the opening of the sixth front passage 102, and together therewith, the first vent blow-out port 106 is blocked by the vent damper 108 (i.e., the condition of the two-dot-dash line shown in FIG. 2). Consequently, a portion of the first air (mixed air), which is mixed in the mixing section 98, passes through the defroster blow-out port 100 and is blown in the vicinity of the front window of the vehicle, while another portion of the first air flows past the sixth and seventh front passages 102, 110 and is blown in the vicinity of the feet of passengers in the front and middle seats in the vehicle compartment from the first and second heat passages 112, 114 and the first and second heat blow-out ports (not shown).
On the other hand, in the heat-defroster mode, in the case that the second air is blown toward the middle seats and rear seats of the vehicle compartment, since this mode is the same as the heat mode discussed above, detailed explanations thereof shall be omitted.
Lastly, the defroster mode for blowing air only in the vicinity of the front widow for eliminating fog (condensation) from the front window in the vehicle shall be described. In this case, the defroster damper 104 is rotated to separate from the defroster blow-out port 100 while the opening of the sixth front passage 102 is blocked, and the first air (mixed air) is supplied from the mixing section 98 to the opened defroster blow-out port 100 and is blown in the vicinity of the front window in the vehicle. In this case, the defroster mode can be handled solely by blowing first air supplied only from the first blower unit 16, without driving the second blower unit 22.
In the foregoing manner, according to the present embodiment, when the sensor 58 is installed, which is capable of detecting the surface temperature on the evaporator 18, the sensor 58 is disposed within a region S1 on the evaporator 18, which is in the vicinity of the supply conduit 46 through which the low temperature coolant medium L is supplied, and on the back surface 18 b side of the evaporator 18 on the side of the supply conduit 46, as well as on the side of the first cooling section 50 that faces the first front passage 34, to which external air containing a comparatively large amount of moisture is supplied from the first blower unit 16. Consequently, the sensor 58 is capable of detecting the temperature of a region of maximum low temperature in the evaporator 18, where there is a fear that freezing caused by adhered moisture is likely to occur.
As a result, for example, by outputting the detected temperature detected by the sensor 58 to an unillustrated controller and monitoring the temperature continuously, it becomes possible for freezing, which is caused by moisture adhered to the front surface 18 a and back surface 18 b of the evaporator 18, to be prevented reliably, and narrowing of ventilation passages inside the evaporator 18 due to such freezing with consequent deterioration in the cooling effectiveness of the evaporator 18 is avoided. Owing thereto, a stable cooling capacity is always obtained in the evaporator 18.
In the above embodiment, a case has been described in which the supply conduit 46 and the discharge conduit 48 are disposed on the first tank portion 40 a constituting the evaporator 18, and together therewith, the first cooling section 50 is disposed on the side of the first tank portion 40 a, and a region S1 for arrangement of the sensor 58 is set in the vicinity of the first tank portion 40 a and the supply conduit 46. However, as shown in FIG. 8, if the supply conduit 46 and the discharge conduit 48 are disposed on the second tank portion 40 b constituting an evaporator 200, and the first cooling section 50 is disposed on the side of the second tank portion 40 b, in this case, the region S1 for arrangement of the sensor 58 is on the side of the back surface 18 b of the evaporator 200, and lies in the vicinity of the second tank portion 40 b and the supply conduit 46 in the first cooling section 50.
More specifically, the region S1 for positioning the sensor 58 is on the side of the back surface 18 b of the evaporator 18, 200 facing one of the tubes 36 b to which the coolant medium L is supplied from the supply conduit 46, and also on the first cooling section 50 on the side of the first front passage 34 to which external air is supplied, while in addition, the region S1 is set at a position in the vicinity of the supply conduit 46 to which the chilled coolant medium L is supplied.
The heat exchanger for use in vehicular air conditioning apparatus according to the present invention is not limited to the above-described embodiments, and it is a matter of course that various modified or additional structures could be adopted without deviating from the essence and gist of the invention.

Claims

1. A heat exchanger for use in a vehicular air conditioning apparatus having a casing including a first passage through which external air flows and a second passage through which internal air flows, and a switching mechanism for switching a flow state of the external air and the internal air in the first passage and the second passage, wherein the heat exchanger is disposed in the interior of the casing so as to straddle between the first passage and the second passage, for thereby cooling and supplying the external air and the internal air, the heat exchanger comprising:

a supply member, which is supplied with a coolant medium that circulates through the interior thereof;

a discharge member, through which the coolant medium that has circulated through the interior is discharged;

a first cooling section, which faces the first passage, for performing cooling of the external air that flows through the first passage;

a second cooling section, which faces the second passage, for performing cooling of the internal air that flows through the second passage; and

a sensor for detecting a temperature of the heat exchanger,

wherein the sensor faces toward the first cooling section, and is disposed at a position proximate to the supply member.

2. The heat exchanger for use in a vehicular air conditioning apparatus according to claim 1, wherein:

the heat exchanger further comprises a plurality of first and second tubes, which are disposed in parallel along a direction of flow of the air that flows through the interior of the casing, and through which the coolant medium flows through the interior thereof; and

the sensor is disposed on a side surface of the heat exchanger that faces toward either of the first tubes or the second tubes, which communicate with the supply member, and to which the coolant medium is supplied from the supply member.