US20120180989A1

US20120180989A1 - Vehicular air-conditioning system

Info

Publication number: US20120180989A1
Application number: US13/348,918
Authority: US
Inventors: Koji Ota; Michio Nishikawa; Nobuharu Kakehashi
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2011-01-14
Filing date: 2012-01-12
Publication date: 2012-07-19
Also published as: DE102012200229A1; JP5533685B2; JP2012144222A

Abstract

A heating-use heat exchanger which includes a first heater core which exchanges heat between a first liquid and air blown into a passenger compartment and a second heater core which exchanges heat between a second liquid which is higher in temperature and smaller in flow rate than the first liquid and blown air which is heated by the first heater core is held in an air-conditioning case so that an inlet side tank part is at the bottom and an exit side tank part is at the top and the tube longitudinal direction is slanted. Due to this, the high temperature second liquid flowing into the second heater core is stored inside of the inlet side tank part in a region above the tube inlet side ends over the entire stacking direction of the plurality of tubes, then flows into the plurality of tubes.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a vehicular air-conditioning system comprising a heating-use heat exchanger which heats air which is blown into a passenger compartment.
2. Description of the Related Art
As such vehicular air-conditioning systems, there are the ones described in U.S. Pat. No. 5,337,704 and European Patent Application Publication No. 1008471.
In the system described in U.S. Pat. No. 5,337,704, as cooling water channels inside of the engine, there are the cylinder head-side channel which cools the cylinder head and the cylinder block-side channel which cools the cylinder block. The cooling water which passes through the cylinder head-side channel is designed to flow into a single heating-use heat exchanger.
In the system described in European Patent Application Publication No. 1008471, two heating-use heat exchangers are provided for heating air. The cooling water which flows out from a single cooling water exit which is provided at the engine is branched and made to flow to the heating-use heat exchangers.

SUMMARY OF THE INVENTION

In this regard, in recent years, the engines which are mounted in vehicles are being required to secure the required output while being made smaller in size. If realizing this by raising the compression ratio or raising supercharging pressure in a supercharged engine, knocking is liable to occur, so it is necessary to improve the anti-knocking performance. Therefore, to improve the anti-knocking performance, it may be considered to positively cool the cylinder head.
However, to suppress an increase in friction inside of the engine for the cylinder block, it is necessary to maintain a predetermined temperature or more. For this reason, as the cooling water channel inside of the engine, it may be considered to provide a cylinder head-side channel and a cylinder block-side channel and make the cooling water flow rate of the cylinder head-side channel greater than the cooling water flow rate of the cylinder block-side channel.
However, in this case, the cooling water temperature after cooling the cylinder head becomes lower than the minimum temperature required for heating. As shown in the art described in U.S. Pat. No. 5,337,704, if heating the air blown into the passenger compartment using as a heat source only the cooling water which cooled the cylinder head, the problem arises that the air temperature cannot be sufficiently raised. Note that, in the past, the cooling water temperature after cooling the cylinder head was 80 to 90° C. This exceeded the minimum temperature required for heating, so this problem did not arise.
Therefore, as a heating-use heat exchanger, one may be considered which includes a first heat exchange part which exchanges heat between the cooling water which cooled the cylinder head and the blown air, and a second heat exchange part which exchanges heat between the cooling, water which cooled the cylinder block and the blown air which was heated at the first heat exchange part.
According to this, the first heat exchange part uses the cooling water which cooled the cylinder block as the heat source to heat the blown air, then the second heat exchange part uses the cooling water after cooling the cylinder block, which is higher in temperature than the cooling water after cooling the cylinder head, as the heat source to further heat the blown air which was heated by the first heat exchange part, so it is possible to sufficiently raise the air temperature after passing through the heating-use heat exchanger.
However, in this case, the cooling water flow rate of the cylinder block-side channel is smaller than the cooling water flow rate of the cylinder head-side channel, so the cooling water which flows into the second heat exchange part becomes smaller in flow rate than the cooling water which flows into the first heat exchange part. For this reason, as explained above, it was learned that in the air-conditioned air after passing through the heating-use heat exchanger, a temperature distribution ends up forming with a large temperature difference in the left-right direction.
That is, the second heat exchange part comprises a plurality of tubes which are stacked together, an inlet side tank part which is connected to first end sides of the plurality of tubes in a longitudinal direction thereof and which forms a cooling water inlet side, and an exit side tank part which is connected to the other end sides of the plurality of tubes in the longitudinal direction thereof and which forms a cooling water exit side. It was learned that when having the second heat exchange part held at the air-conditioning case so that the inlet side tank part is positioned at the bottom side and the exit side tank part is positioned at the top side and the cooling water flows from the bottom to the top inside of the second heat exchange part, the phenomenon ends up arising that most of the cooling water which flows into the inlet side tank part flowing through the tubes close to the cooling water inlet and the cooling water has a hard time flowing up to the tubes far from the cooling water inlet.
This is due to the following reason. In general, when there is a high temperature part at the bottom side of the inside of a liquid, that high temperature part rises due to its buoyancy. Further, in the second heat exchange part, the cooling water flows through the inside of the tubes while exchanging heat with the air. The cooling water which flows into the inlet side tank part is higher in temperature than the cooling water inside of the exit side tank part. For this reason, the high temperature cooling water which flows into the inlet side tank part is affected by buoyancy. Furthermore, if the cooling water which flows into the second heat exchange part becomes a low flow velocity of a flow rate smaller than the cooling water which flows into the first heat exchange part, this effect of buoyancy becomes further larger.
If the air-conditioned air after passing through the heating-use heat exchanger ends up with a temperature distribution with a large temperature difference in the left-right direction, for example, the air-conditioned air after passing through the heating-use heat exchanger ends up branching to one side and the other side in the vehicle left-right direction. When air-conditioned air is blown out from a driver-side vent and a passenger-side vent, a difference ends up arising in the vented air temperature at the driver's side and the passenger's side.
Note that, such a problem is not limited to the case where the first heat exchange part uses the cooling water after cooling the cylinder head as a heat source and where the second heat exchange part uses the cooling water after cooling the cylinder block as a heat source. It is a problem which arises when the first heat exchange part uses a first liquid as a heat source and when the second heat exchange part uses a second liquid with a temperature higher than and flow rate smaller than the first liquid as a heat source.
The present invention is made in consideration of the above point and has as its object the provision of a vehicular air-conditioning system which can reduce the temperature difference in the left-right direction which occurs in air-conditioned air after passing through a heating-use heat exchanger.
To achieve this object, a first aspect of the present invention provides a vehicular air-conditioning system wherein a second heat exchange part (20) stores a second liquid which flows into an inlet side tank part (22) and which is higher in temperature than a liquid in an exit side tank part (23) inside of liquid storage parts (71, 72, 73, 74) inside of an inlet side tank part across an entire stacked direction of the plurality of tubes (21), then runs it into the plurality of tubes (21).
According to the present invention, by employing such a constitution, even if the second liquid which flows through the second heat exchange part is lower in flow velocity than the first liquid which flows through the first heat exchange part, it is possible to reduce the temperature difference of the cooling water which flows through the plurality of tubes and possible to reduce the temperature difference in the left-right direction occurring in air-conditioned air after passing through the heating-use heat exchanger.
In the present invention, the second heat exchange part (20) may be made to slant so as to form a liquid storage part (71) at the inside of the inlet side tank part (22) in a region above inlet side ends (21 a) of the tubes (21).
Further, in the present invention, part of a wall (91) forming the inlet side tank part (22) may be made to bulge outward from the other parts so as to form a liquid storage part (72).
Further, in the present invention, an insertion length (84) of tubes (21) which are inserted at an inlet side tank part (22) of the second heat exchange part (20) may be made longer than an insertion length (85) of tubes (11) which are inserted at the inlet side tank part (12) of the first heat exchange part (20) so as form a liquid storage part (74) in the inside of the inlet side tank part (22) of the second heat exchange part (10) in a region above the inlet side ends (21 a) of the tubes (21) in the gravity direction.
In this regard, when projecting the end opening (20 a) of a liquid introduction path in the inlet side tank part (22) of the second heat exchange part (20) in a longitudinal direction of the inlet side tank part (22), if the end opening (20 a) of the liquid introduction path is positioned right under the inlets of the tubes (21), the high temperature liquid which flows into the inlet side tank part rises due to buoyancy, so when high temperature liquid flows into the inlet side tank part, the high temperature liquid ends up flowing into the tubes positioned above inflowing liquid.
Therefore, in the present invention, at least part of the end opening (20 a) of the liquid introduction path is preferably positioned at a position other than right under the inlets of the tubes (21) in the gravity direction.
According to this, part of the end opening of the liquid introduction path is outside from the range right under the tubes, so it is possible to reliably guide part of the high temperature second liquid which flowed in from the end opening of the liquid introduction path to the liquid storage part.
As the constitution where at least part of the end opening (20 a) of the liquid introduction path is positioned other than right under the inlets of the tubes (21), the present invention can employ a constitution where at least part of the end opening (20 a) of the liquid introduction path is positioned outside from between two imaginary lines (81, 82) which are drawn from the inner walls (21 b) of the tubes (21) at the inlet side ends (21 a) of the tubes (21) in parallel in the gravity direction. Further, it is also possible to employ a constitution in which at least part of the end opening (20 a) of the liquid introduction path is positioned above an imaginary line (83) which passes through the inlet side end faces (21 a) of the tubes (21). Note that, it is also possible to employ both the configurations.
Further, in the present invention, a part of 35% or more of the total area of the end opening (20 a) of the liquid introduction path is preferably positioned other than right under the inlets of the tubes (21) in the gravity direction. Due to this, it is possible to particularly reduce the temperature difference of the left-right vented air from the heating-use heat exchanger as shown in the later explained FIG. 10.
Further, in the present invention, the second heat exchange part (20) is preferably mounted in a vehicle in a slanted state so that the second liquid flows in from one end side of the inlet side tank part (22) in the longitudinal direction thereof and so that the top wall of the inlet side tank part (22) is arranged with a first end side of the inlet side tank part (22) in the longitudinal direction positioned above the other end side in the longitudinal direction in the gravity direction. Due to this, compared with the case where the top wall of the inlet side tank part is horizontal, it is possible to easily guide the high temperature liquid which flows through the liquid storage part to the first end side of the inlet side tank part in the longitudinal direction.
Further, in the present invention, inside of the inlet side tank part (22) of the second heat exchange part (20), it is also possible to provide a flow velocity raising means (92) for raising the flow velocity of the second liquid which flows to the inlet side tank part (22).
According to this, it is possible to raise the flow velocity of the second liquid which flows into the inlet side tank part after passing through the flow velocity raising means (92) compared with before passing, so compared with the case of not providing means for raising the flow velocity of the cooling water, it is possible to run cooling water until the side of the inlet side tank part away from the second liquid inlet. Accordingly, according to the present invention, compared with the case of forming the liquid storage part, Furthermore, it is possible to reduce the temperature difference of the cooling water which flows through the plurality of tubes and possible to reduce the temperature difference in the left-right direction occurring in the air-conditioned air after passing through the heating-use heat exchanger.
Further, in the present invention, it is possible to make the channel sectional area of the inlet side tank part (22) of the second heat exchange part (20) smaller than that of the first heat exchange part (10), possible to make the channel sectional area of a liquid introduction path which introduces the second liquid to the inlet side tank part (22) of the second heat exchange part (20) smaller than that of the first heat exchange part (10), and possible to adopt both constitutions.
In this way, by raising the flow velocity of the second liquid which flows into the inlet side tank part, it is possible to run cooling water up to the side of the inlet side tank part away from the second liquid inlet.
Further, a second aspect of the present invention provides a vehicular air-conditioning system which provides, at the inside of the inlet side tank part (22) of the second heat exchange part (20), a flow velocity raising means (92) for raising the flow velocity of the second liquid which flows into the inlet side tank part (22).
According to this, it is possible to raise the flow velocity of the second liquid which flows into the inlet side tank part after passing through the flow velocity raising means (92) compared with before passing through it, so compared with the case of not providing means for raising the flow velocity of the cooling water, it is possible to run the cooling water to the side of the inlet side tank part away from the second liquid inlet. Accordingly, according to the present invention, it is possible to reduce the temperature difference of the cooling water flowing through the plurality of tubes and possible to reduce the temperature difference in the left-right direction occurring in the air-conditioned air after passing through the heating-use heat exchanger.
In the present invention, the flow velocity of the second liquid which flows through the inlet side tank part (22) of the second heat exchange part (20) is preferably made the same or equal to the flow velocity of the first liquid which flows through the inlet side tank part (12) of the first heat exchange part (10).
Note that the reference signs in parentheses after the means described in this section and the claims show the correspondence with specific means described in the embodiments explained later.
The present invention may be more fully understood from the description of preferred embodiments of the invention, as set forth below, together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic view of the configuration of a vehicular air-conditioning system of a first embodiment;

FIG. 2 is a side view of a heating-use heat exchanger in FIG. 1 in the state held in an air-conditioning case;

FIG. 3 is a front view of the heating-use heat exchanger in FIG. 1;

FIG. 4 is a front view of a second heater core showing the flow of cooling water in the first embodiment;

FIG. 5 is a front view of a second heater core showing the flow of cooling water in Comparative Example 1;

FIG. 6 is a cross-sectional view of a heating-use heat exchanger in a second embodiment;

FIG. 7 is a cross-sectional view of a heating-use heat exchanger in a third embodiment;

FIG. 8 is a side view of a heating-use heat exchanger 2 for explaining a slant angle θ1 of the second heater core 20 in the third embodiment;

FIG. 9 is a view showing the relationship between a temperature difference of left-right vented air from the heating-use heat exchanger 2 and the slant angle θ1 shown in FIG. 8;

FIG. 10 is a view showing the relationship between the temperature difference of left and right vented air from the heating-use heat exchanger 2 and the ratio of an area of a part at a position other than right under the inlets of the tubes 21 with respect to the total area of the cooling water inlet 20 a;

FIG. 11 is a cross-sectional view of a heating-use heat exchanger in a fourth embodiment;

FIG. 12 is a cross-sectional view of a heating-use heat exchanger in a fifth embodiment;

FIG. 13 is a cross-sectional view of a heating-use heat exchanger in a sixth embodiment;

FIG. 14 is a front view of a heating-use heat exchanger in a seventh embodiment;

FIG. 15 is a view showing the relationship of the slant angle θ2 of the heating-use heat exchanger in the seventh embodiment and the left-right vented air temperature difference;

FIG. 16 is a cross-sectional view of a heating-use heat exchanger in an eighth embodiment;

FIG. 17 is a cross-sectional view of a heating-use heat exchanger in a ninth embodiment;

FIG. 18A is a side view of a heating-use heat exchanger in a 10th embodiment;

FIG. 18B is a front view of the heating-use heat exchanger in the 10th embodiment; and FIG. 19 is a side view of a heating-use heat exchanger in an 11th embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Below, embodiments of the present invention will be explained based on the drawings. Note that, in the following embodiments, the same or equivalent parts are assigned the same reference signs and explanations are omitted.

First Embodiment

FIG. 1 shows the schematic configuration of a vehicular air-conditioning system in the present embodiment. The vehicular air-conditioning system of the present embodiment is mounted in a hybrid vehicle which obtains drive power for driving the vehicle from an engine (internal combustion engine) and driving-use electric motor.
The vehicular air-conditioning system 1 of the present embodiment is provided with a heating-use heat exchanger 2 which exchanges heat between cooling water of an engine 30 and air blown into a passenger compartment so as to heat the air blown into the passenger compartment. Note that, the cooling water is water or water containing added ingredients.
The heating-use heat exchanger 2 has a first heater core 10 and a second heater core 20. The two are integrally formed. The first heater core 10 and the second heater core 20 respectively correspond to the first heat exchange part and the second heat exchange part of the heating-use heat exchanger in the present invention.
The first heater core 10 is run through by cooling water which cooled the cylinder head 31 of the engine 30, while the second heater core 20 is run through by cooling water which cooled the cylinder block 32 of the engine 30. The first heater core 10 is positioned at the upstream side in the air flow, while the second heater core 20 is positioned at the downstream side in the air flow.
Here, in the engine 30, the cylinder block 32 is a block member which forms cylinder bores (columnar holes) through which pistons move reciprocatively. The cylinder head 31 is a block member which closes the openings at the top dead center side of the cylinder bores so as to form combustion chambers.
At the cylinder head 31 side of the engine 30, a first cooling water inlet 31 a and a first exit part comprised of a first cooling water exit 31 b are provided. Inside of the cylinder head 31, a cylinder head-side cooling water channel through which cooling water which cools the cylinder head 31 flows is formed. The cooling water which flows from the first cooling water inlet 31 a flows through the inside of the cylinder head 31, then flows out from the first cooling water exit 31 b.
In the same way, at the cylinder block 32 side of the engine 30, a second cooling water inlet 32 a and a second exit part comprised of a second cooling water exit 32 b are provided. Inside of the cylinder block 32, a cylinder block-side cooling water channel through which cooling water which cools the cylinder block 32 flows is formed. The cooling water which flowed from the second cooling water inlet 32 a flows through the inside of the cylinder block 32, then flows out from the second cooling water exit 32 b. In this way, in the present embodiment, the cooling water which cooled the cylinder block 32 flows out from the second cooling water exit 32 b without merging with the cooling water which cooled the cylinder head 31.
In this way, the engine 30 of the present embodiment has two cooling systems. Further, at the time of steady operation of the engine 30, the cooling water flow rate of the cylinder head-side cooling water channel is made larger than the cooling water flow rate of the cylinder block-side cooling water channel so as to cool the cylinder head 31 more positively than the cylinder block 32. This is to make the cylinder head 31 lower in temperature so as to improve the anti-knocking performance and to maintain the cylinder block 32 at a high temperature to maintain the low viscosity of the engine oil so as to suppress the increase in friction inside of the engine.
In the heating-use heat exchanger 2, the cooling water inlet 10 a of the first heater core 10 is connected through a pipeline to the first cooling water exit 31 b at the cylinder head 31 side of the engine 30. The cooling water which flows out from the first cooling water exit 31 b flows to the first heater core 10. On the other hand, the cooling water inlet 20 a of the second heater core 20 is connected through a pipeline to a second cooling water exit 32 b at the cylinder block 32 side of the engine 30. The cooling water which flows out from the second cooling water exit 32 b flows into the second heater core 20.
Therefore, in the present embodiment, low temperature, large flow rate cooling water flows into the first heater core 10, while high temperature, small flow rate cooling water flows into the second heater core 20. Specifically, the temperature and flow rate of the cooling water which flows into the first heater core 10 are 30 to 60° C. and 5 to 15 L/min in range, while the temperature and flow rate of the cooling water which flows into the second heater core 20 are 40 to 90° C. and 0.2 to 3 L/min in range.
The first heater core 10 and the second heater core 20, as explained later, have independent heat exchange core parts. For this reason, the cooling water which flows into the first heater core 10 exchanges heat with the air at the heat exchange care part of the first heater core 10 without being mixed with the cooling water which flows into the second heater core 20. In the same way, the cooling water which flows into the second heater core 20 exchanges heat with the air at the heat exchange core part of the second heater core 20 without being mixed with the cooling water which flows into the first heater core 10. Further, the flows of cooling water which passed through the heat exchange core parts are merged, then flows out from a common cooling water exit 2 b provided at the heating-use heat exchanger 2.
The cooling water flowing out from the cooling water exit 2 b of the heating-use heat exchanger 2 is branched at the branching part 41 and then flows to the first cooling water inlet 31 a and the second cooling water inlet 32 a of the engine 30.
As shown in FIG. 1, a water pump 42 is arranged in the middle of the cooling water channel between the cooling water exit 2 b of the heating-use heat exchanger 2 and the branching part 41. The water pump 42 is a means which forms a flow of cooling water and an adjusting means for adjusting the cooling water flow rate. The water pump 42 is an electric pump. A not shown control device is used to control its speed to thereby control the cooling water flow rate.
Note that, the engine 30 is communicated with a not shown radiator. Cooling water which flow out from the cylinder head 31 radiates heat at the radiator. After radiating heat, the cooling water can flow into the cylinder head 32. The cooling water which flow out from the cylinder block 32 radiates heat at the radiator. After radiating heat, the cooling water can flow to the cylinder block 32.
Next, details of the heating-use heat exchanger 2 will be explained. FIG. 2 shows a side view of a heating-use heat exchanger 2 in the state held at an air-conditioning case 51, while FIG. 3 is a front view of the heating-use heat exchanger 2 as seen from the downstream side of the air flow. Note that, the up and down direction arrows in the figures show the up-down direction parallel to the gravity direction in the state mounted on a vehicle. The same is true for other drawings. The vehicle at this time is positioned on a horizontal surface, not a slanted surface.
As shown in FIGS. 2 and 3, the first and second heater cores 10, 20 of the heating-use heat exchanger 2 are both provided with pluralities of stacked flat tubes 11, 21, inlet side tank parts 12, 22 which are communicated with the pluralities of tubes 11, 21 at one end side in the longitudinal direction and which become the cooling water inlet side, and exit side tank parts 13, 23 which are communicated with the pluralities of tubes 11, 21 at the other end side in the longitudinal direction and which become the cooling water exit side.
The heating-use heat exchanger 2 is housed in the air-conditioning case 51 along with a not shown blower which forms blown air directed to the inside of the passenger compartment and then is mounted in a vehicle. Specifically, as shown in FIG. 2, the heating-use heat exchanger 2 is held in the air-conditioning case 51 in a slanted state so that the second heater core 20 is positioned at the downstream side in the air from the first heater core 10. “In the slanted state” means a state in which the air outflow/inflow surfaces of the heating-use heat exchanger 2 are not parallel to both the vertical direction and horizontal direction and in which the angle formed by the air outflow/inflow surfaces and the vertical direction forms an acute angle. Further, the orientation of the air outflow/inflow surfaces of the heating-use heat exchanger 2 matches the longitudinal direction of the tubes 21 when viewing the heating-use heat exchanger 2 from the side direction. In the present embodiment, the heating-use heat exchanger 2 is slanted so that the second heater core 20 is positioned above the first heater core 10. For this reason, directions of air flows which pass through the first and the second heater cores 10, 20 are upward slanted directions.
Note that, in the present embodiment, as shown in FIG. 3, the heating-use heat exchanger 2 is mounted in the vehicle so that the top wall of the inlet side tank part 22 of the second heater core 20 becomes parallel to the horizontal direction when viewing the second heater core 20 from the front.
The air-conditioning case 51, while not shown, is provided with a bypass air passage through which blown air flows bypassing the heating-use heat exchanger 2 and an air mix door which adjusts the mixing ratio of the air after passing through the bypass air passage and the air after passing through the heating-use heat exchanger 2. Note that, the air channel through which air after passing through the heating-use heat exchanger 2 flows is connected at its bottom side to the foot vents and at its top side to the defroster vents and face vents.
The inlet side tank parts 12, 22 of the first and second heater cores 10, 20 are comprised of a single inlet side tank 61 which is divided into two by a partition wall 62. They are provided with cooling water inlets 10 a, 20 a. The cooling water inlets 10 a, 20 a are openings which are formed in the walls forming the inlet side tank parts 12, 22. They are end openings of the cooling water introduction path which face the insides of the inlet side tank parts 12, 22 and which introduce cooling water to the inlet side tank parts 12, 22. These cooling water inlets 10 a, 20 a are arranged at one end side of the inlet side tank parts 12, 22 in the vehicle left-right direction (left-right direction of FIG. 3).
The exit side tank parts 13, 23 of the first and second heater cores 10, 20 are comprised of a single exit side tank 63. This exit side tank 63 is provided with a single cooling water exit 2 b. For this reason, inside of the exit side tank 63, the cooling water which flows into the first heater core 10 and the cooling water which flows into the second heater core 20 merge. The merged cooling water flows out from a single cooling water exit 2 b. Note that, the cooling water exit 2 b is arranged at one end side in the vehicle left-right direction the same as the cooling water inlets 10 a, 20 a.
In this way, in the present embodiment, the exit side tank part of the first and second heater cores 10, 20 is made a common part and the cooling water exit 2 b of the heating-use heat exchanger 2 is made a single exit, but it is also possible to provide each of the first and second heater cores 10, 20 with an exit side tank part and cooling water exit. However, from the viewpoint of reducing the pipelines connecting the heating-use heat exchanger 2 and the engine 30 and reducing the number of water pumps explained later, this embodiment is preferable.
The inlet side tank parts 12, 22 of the first and second heater cores 10, 20 are positioned at the lower side, while the exit side tank parts 13, 23 of the first and second heater cores 10, 20 are positioned at the upper side. For this reason, in both the first heater core 10 and the second heater core 20, the cooling water flows from the bottom toward the top.
At both the first and second heater core 10, 20, a plurality of tubes 11, 21 extend in one direction. They are stacked so as to be arranged in lines in a direction vertical to that one direction, that is, the vehicle left-right direction. The inlet side tank parts 12, 22 and exit side tank parts 13, 23 are shaped to extend elongated in the stacking directions of the tubes 11, 21. Therefore, the “vehicle left-right direction” corresponds to the stacking directions of the tubes 11, 21 and the longitudinal directions of the inlet side tank parts 12, 22.
The first and second heater cores 10, 20 are provided with corrugated heat conduction fins 14, 24 which are joined to the outer surfaces of the tubes 11, 21. At the first and second heater cores 10, 20, due to the stacked structures of the tubes 11, 21 and heat conduction fins 14, 24, total pass type, that is, one-directional flow type first and second heat exchange core parts 15, 25 are formed.
The first heater core 10 and the second heater core 20 are equal in size in the left-right and top-bottom directions when viewed by the direction of air flow. Due to this, all of the air which passes through the first heater core 10 passes through the second heater core 20.
Further, the first heater core 10 and the second heater core 20 differ in thickness in the direction of air flow. Specifically, if comparing the widths in the direction of air flow of the tubes 11, 21 and the heat conduction fins 14, 24, the first heater core 10 is longer than the second heater core 20. For this reason, the heat exchange area of the air and the cooling water becomes greater at the first heater core 10 than at the second heater core 20.
Further, the channel sectional area of the tubes 11 of the first heater core 10 is larger than the channel sectional area of the tubes 21 of the second heater core 20, and therefore the flow resistance in the first heater core 10 is lower than the flow resistance in the second heater core 20. For this reason, the first heater core 10 becomes greater in flow rate of cooling water flowing through the inside than the second heater core 20.
Next, the operation of the vehicular air-conditioning system of the present embodiment 1 will be explained.
A not shown control device of the vehicular air-conditioning system 1 controls the blower to obtain a blowing rate in accordance with the target vented air temperature TAO at the time of heating and controls the air mix door so as to obtain the desired position. The target vented air temperature TAO is calculated in accordance with the air-conditioning heat load determined by the temperature setting and environmental conditions and is a target temperature of the air which is vented from the vents to the inside of the passenger compartment.
Due to this, in the first heater core 10, heat exchange with the cooling water after cooling of the cylinder head 31 is used to heat the blown air. The cooling water after cooling of the cylinder head 31 positively cools the cylinder head 31, so is lower in temperature than the minimum temperature required for heating, but is larger in flow rate than the cooling water after cooling of the cylinder block 32 and has a large heat content. Therefore, in the present embodiment, to take out as much of the heat content of the cooling water after cooling of the cylinder head 31 as possible, the cooling water flow rate at the inside of the first heater core 10 is increased compared with the second heater core 20 and the heat conduction coefficient of the air and cooling water is increased. For this reason, in the first heater core 10, it is possible to supply the blown air with a large heat content from the large flow rate cooling water after cooling of the cylinder head 31. As a result, the temperature of the air after passing through the first heater core 10 becomes a temperature close to the cooling water temperature before flowing into the first heater core 10 (inlet water temperature of first heater core).
Further, in the second heater core 20, heat exchange with the cooling water after cooling of the cylinder block 32 is used to heat the blown air after passing through the first heater core 10. The cooling water after cooling the cylinder block 32 is higher in temperature than the cooling water after cooling the cylinder head 31, so it is possible to raise the temperature of the blown air after passing through the second heater core 20 to a temperature further higher than the blown air after passing through the first heater core 10.
In this regard, unlike in the present embodiment, as described in U.S. Pat. No. 5,337,704, only the cooling water which cools the cylinder head 31 is used as a heat source for heating the air, so the air temperature cannot be sufficiently raised and heating cannot be achieved. Further, when ending up mixing all of the cooling water after cooling of the cylinder head 31 which flows out from the engine and the cooling water after cooling of the cylinder block 32, the cooling water temperature after mixing becomes lower than the minimum temperature required for heating. For this reason, the efficiency of energy transfer from the cooling water to the air becomes lower, so even if using the cooling water after mixing as the heat source to heat the air, it is not possible to sufficiently raise the air temperature and heating cannot be achieved.
As opposed to this, in the present embodiment, the engine 30 is provided with the first cooling water exit 31 b and the second cooling water exit 32 b, the low temperature side cooling water after cooling the cylinder head 31 is made to flow out from the first cooling water exit 31 b, and the high temperature side cooling water after cooling the cylinder block 32 is made to flow out from the second cooling water exit 32 b. Further, without allowing the two flows of cooling water to be mixed, the low temperature side cooling water which flows out from the first cooling water exit 31 b is made to flow to the first heater core 10, and the high temperature side cooling water which flows out from the second cooling water exit 32 b is made to flow to the second heater core 20.
In this way, in the present embodiment, in the second heater core 20, the high temperature side cooling water which flows out from the second cooling water exit 32 b is used as a heat source to heat the air blown into the passenger compartment, so when compared with the case of using only the low temperature side cooling water which flows out from the first cooling water exit 31 b as a heat source and the case of using mixed water of the low temperature side cooling water and high temperature side cooling water mixed together, it is possible to raise the air temperature after heating at the second heater core 20.
Furthermore, in the present embodiment, the first heater core 10 uses the low temperature side cooling water as a heat source to heat the blown air, then this heated air is heated at the second heater core 20 using the high temperature side cooling water as a heat source, so it is possible to effectively utilize the heat contents of both the low temperature side cooling water and the high temperature side cooling water.
That is, according to the present embodiment, compared with the case of using a mixture of the cooling water as a whole which flows out from both the first and second cooling water exit parts 31 b, 32 b as a heat source for heating the air blown into the passenger compartment by a single heater core, it is possible to raise the efficiency of energy transfer from the cooling water to the air in the cooling water as a whole at the heater core. As a result, even when the blowing rate of the blower is large, it is possible to raise the air to a sufficiently high temperature and possible to achieve heating.
Next, the main features of the vehicular air-conditioning system of the present embodiment 1 will be explained.
FIGS. 4 and 5 show the flows of cooling water in the second heater core 20 in the present embodiment and Comparative Example 1, respectively. Comparative Example 1 sets the air-conditioning case 51 vertical so that the heating-use heat exchanger 2 has an air inflow surface parallel to the vertical direction. Further, in Comparative Example 1, when projecting the cooling water inlet 20 a in the longitudinal direction of the inlet side tank part 22, the entire part of the cooling water inlet 20 a of the inlet side tank part 22 is right under the inlet side end 21 a of the tube 21. The high temperature cooling water is not stored in the liquid storage part.
When the cooling water which flows into the second heater core 20 has a lower flow velocity and lower flow rate than the cooling water which flows into the first heater core 10, in Comparative Example 1 shown in FIG. 5, the phenomenon ends up arising that most of the high temperature cooling water which flows into the inlet side tank part 22 flows through the tubes close to the cooling water inlet and it is difficult for the cooling water to flow up to the tubes far from the cooling water inlet.
As opposed to this, in the present embodiment, as shown in FIG. 2, the second heater core 20 is made to slant, so in the region of the inlet side tank part 22 which is above the inlet side ends 21 a of the tubes 21, a liquid storage part 71 is formed in which the high temperature cooling water is stored across the entire region of the plurality of tube 21 in the stacked direction. This liquid storage part 71 is formed into a corner part which is positioned at the highest position in the corner part of the inlet side tank part 22.
For this reason, as shown in FIG. 4, the cooling water which flowed to the inlet side tank part 22 and which is higher in temperature than the cooling water inside of the exit side tank part is stored in the liquid storage part 71 due to the buoyancy effect, then flows from this liquid storage part 71 to the plurality of tubes.
In particular, in the present embodiment, as shown in FIG. 2, when projecting the cooling water inlet 20 a in the longitudinal direction of the inlet side tank part 22 (direction vertical to paper surface in FIG. 2), part of the cooling water inlet 20 a is positioned at the outside from a tube inside extension line (imaginary line) 81 drawn parallel in the gravity direction from the tube inside walls 21 b of the tubes 21 at the inlet side end 21 a.
Here, when projecting the cooling water inlet 20 a in the longitudinal direction of the inlet side tank part 22, if all of the cooling water inlet 20 a of the inlet side tank part 22 is positioned right under the inlets of the tubes 21 in the gravity direction, the high temperature cooling water which flows into the inlet side tank part 22 will rise due to buoyancy, so when high temperature cooling water flows in from the cooling water inlet 20 a to the inlet side tank part 22, the high temperature cooling water will end up flowing in to the tubes 21 positioned above the inflowing cooling water.
As opposed to this, in the present embodiment, part of the cooling water inlet 20 a is positioned other than right below the inlets of the tubes 21, so part of the high temperature cooling water which flows in from the cooling water inlet 20 a can be reliably guided to the liquid storage part 71.
Therefore, according to the present embodiment, compared with Comparative Example 1, it is possible to reduce the temperature difference in the vehicle left-right direction of the cooling water which flows through the heat exchange core part 25. Accordingly, according to the present embodiment, it is possible to reduce the temperature difference in the vehicle left-right direction caused by the air-conditioned air after passing through the heating-use heat exchanger 2.
As a result, when the air-conditioned air after passing through the heating-use heat exchanger 2 is branched to one side and the other side in the vehicle left-right direction and air-conditioned air is vented from the driver side vents and passenger side vents, the temperature difference of the vented air at the driver's side and passenger side in the passenger compartment is reduced.
Further, according to the present embodiment, compared with Comparative Example 1, the substantial heat exchange area at the heat exchange core part 25 increases, so the heat content which can be taken from the cooling water at the heat exchange core part 25 is improved and the heat exchange performance is improved.

Second Embodiment

FIG. 6 is a cross-sectional view of the heating-use heat exchanger 2 in the present embodiment. FIG. 6 is a view seen along the same direction as FIG. 2.
In the present embodiment as well, as shown in FIG. 6, the second heater core 20 is slanted, so a liquid storage part 71 is formed in the region of the inlet side tank part 22 above the inlet side ends 21 a of the tubes 21.
Furthermore, in the present embodiment, the positional relationship between the cooling water inlet 20 a and the tubes 21 at the inlet side tank part 22 of the second heater core 20 is as follows: That is, as shown in FIG. 6, when projecting the cooling water inlet 20 a at the longitudinal direction of the inlet side tank part 22, part of the cooling water inlet 20 a (not hatched region in FIG. 6) is positioned below the inlet side ends of the tubes 21 (bottom end face) 21 a.
Further, the majority of the cooling water inlet 20 a (hatched region in FIG. 6) is positioned outside from between two imaginary lines 81, 82 drawn from the tube inside walls 21 b of the tubes 21 at the inlet side ends 21 a parallel in the gravity direction. Here, “the majority of the cooling water inlet 20 a” means a part accounting for 50% or more of the area of the cooling water inlet 20 a. Further, the position at the lower side from the inlets of the tubes 21 between the two imaginary lines 81, 82 is a position right below the inlets of the tubes 21.
In this way, in the present embodiment, 50% or more of the total area of the cooling water inlet 20 a, that is, the majority, sticks out to the outside from the region between the two imaginary lines 81, 82, so it is possible to guide at least half of the cooling water which flows in from the cooling water inlet 20 a to the liquid storage part 71.

Third Embodiment

FIG. 7 is a cross-sectional view of a heating-use heat exchanger 2 in the present embodiment. FIG. 7 is a view seen along the same direction as FIG. 2.
In the present embodiment as well, as shown in FIG. 7, the second heater core 20 is slanted. In the same way as the first and second embodiments, a not shown liquid storage part is formed in the inlet side tank part 22 in the region above the inlet side ends 21 a of the tubes 21.
Further, the positional relationship between the cooling water inlet 20 a and the tubes 21 at the inlet side tank part 22 of the second heater core 20 is as follows:
That is, as shown in FIG. 7, when projecting the cooling water inlet 20 a in the longitudinal direction of the inlet side tank part 22, part of the cooling water inlet 20 a (non-hatched region in FIG. 7) is positioned right under the inlet side ends (bottom end faces) 21 a of the tubes 21. The rest of the cooling water inlet 20 a (hatched part in FIG. 7) is positioned other than right below the tubes 21. Specifically, part of the cooling water inlet 20 a (hatched region in FIG. 7 with direction of hatching from top left to bottom right) is positioned outside from between two imaginary lines 81, 82 drawn from the tube inside walls 21 b of the tubes 21 at the inlet side end 21 a in parallel in the gravity direction. Furthermore, part of the cooling water inlet 20 a (hatched region in FIG. 7 with direction of hatching from top right to bottom left) is positioned at the upper side of the imaginary line 83 extending in line with the inlet side ends 21 a of the tubes 21, while part of the cooling water inlet 20 a overlaps the tubes 21 in positional relationship. Note that, “the inlet side end 21 a through which the imaginary line 83 passes” is the inlet side end faces of the tubes 21 when projecting the cooling water inlet 20 a in the longitudinal direction of the inlet side tank part 22. Further, “positioned at the upper side of the imaginary line 83” means positioned at the other end side of the tubes 21 in the longitudinal direction than the imaginary line 83.
Incidentally, when, like with the first heater core 10, the inflowing cooling water is large in flow rate, if positioning part of the cooling water inlet at the upper side from the inlet side end faces of the tubes and making part of the cooling water inlet overlap the tubes in positional relationship, the problem arises of the pressure loss increasing when the cooling water flows through the inlet side tank part 22, so this positional relationship cannot be employed. As opposed to this, when, like with the second heater core 20, the inflowing cooling water is small in flow rate, the problem of increase of the pressure loss does not arise, so a positional relationship where part of the cooling water inlet 20 a overlaps the tubes 21 can be employed.
In this way, by positioning part of the cooling water inlet 20 a at the outside from between two imaginary lines 81, 82 parallel in the gravity direction and, further, positioning it at the upper side from the inlet side end face of the tubes 21 as well, part of the high temperature cooling water which flows in from the cooling water inlet 20 a can be reliably guided to the liquid storage part 71. As a result, according to the present embodiment, it is possible to reduce the temperature difference in the vehicle left-right direction occurring in the air-conditioned air after passing through the heating-use heat exchanger 2.
Here, the relationship between the ratio of the area of the part of the cooling water inlet 20 a positioned other than right below the inlets of the tubes 21 with respect to the total area (below simply referred to as the “area ratio”) and the effect of reduction of the temperature difference in the vehicle left-right direction occurring in the air-conditioned air after passing through the heating-use heat exchanger 2 will be explained.
FIG. 8 is a side view of the heating-use heat exchanger 2 for explaining the slant angle θ1 of the second heater core 20. FIG. 9 shows the results of evaluation showing the relationship between the temperature difference of the left-right vented air from the heating-use heat exchanger 2 and the slant angle θ1 shown in FIG. 8. FIG. 10 shows the results of evaluation when changing the abscissa in FIG. 9 from the slant angle θ1 to the area ratio. The slant angle θ1, as shown in FIG. 8, is the angle formed by the longitudinal direction of the tubes 21 and the vertical direction when viewing the heating-use heat exchanger 2 from the side. The “temperature difference of the left-right vented air from the heating-use heat exchanger 2” is the difference (absolute value) between the average temperature of the vented air from one half of the heating-use heat exchanger in the left-right direction and the average temperature of the vented air from the other half.
In the heating-use heat exchanger 2 shown in FIG. 8, in the same way as the heating-use heat exchanger shown in FIG. 3, the cooling water inlet 20 a is provided at the end at one side in the left-right direction. Further, in the heating-use heat exchanger 2 shown in FIG. 8, in the direction of air flow, the diameter of the cooling water inlet 20 a is substantially equal to the inside diameter of the tube 21, the center of the cooling water inlet 20 a and the center of the tubes 21 are the same position, and part of the cooling water inlet 20 a is positioned at the upper side from the inlet side end face of the tubes 21.
In such a heating-use heat exchanger 2, if the slant angle θ1 changes, the area ratio also changes. Specifically, the slant angle θ1 in FIGS. 9 of 0, 10, 20, 50, and 90 degrees corresponds to an area ratio in FIG. 10 of 8, 25, 35, 65, and 100%. When the slant angle θ1 is 0 degree, the area of the part of the cooling water inlet 20 a positioned outside from between the two imaginary lines 81, 82 parallel in the gravity direction (see hatched region of FIG. 7 with direction of hatching from top left to bottom right) becomes the minimum. If increasing the slant angle θ1, as shown in FIG. 7, the cooling water inlet 20 a increases in area of the part positioned outside from between the imaginary lines 81, 82 parallel in the gravity direction. When the slant angle θ1 is 90 degrees, the inlet side end faces of the tubes 21 become parallel to the vertical direction, so the imaginary lines 81, 82 overlap into one. There is no region of the tubes 21 right below the inlet, so the area ratio becomes 100%. Note that, the area of the part where the cooling water inlet 20 a overlaps the tubes 21 is constant regardless of the slant angle θ.
As shown in FIGS. 9 and 10, the temperature difference of the left-right vented air from the heating-use heat exchanger 2 tends to become smaller as the slant angle θ1 increases, that is, the area ratio increases. In particular, the temperature difference of the left-right vented air when the slant angle θ1 is 20 degrees or more, that is, the area ratio is 35% or more, becomes close to the temperature difference when the slant angle θ1 is 90 degrees, that is, the area ratio is 100%. From this, to particularly reduce the temperature difference of the left-right vented air from the heating-use heat exchanger 2, it can be said preferable that the area ratio be made 35% or more.
Further, in the present embodiment, the part of the cooling water inlet 20 a overlaps with the tube 21 in the positional relationship. As will be understood from a comparison of the inlet side tank part 22 in FIG. 6 explained in the second embodiment, the dimension of the inlet side tank part 22 in the tube longitudinal direction can be reduced.
Note that, in the present embodiment, to enable part of the cooling water inlet 20 a (hatched region in FIG. 7) to be positioned other than right under the tubes 21, part of the cooling water inlet 20 a is positioned outside from between two imaginary lines 81, 82 parallel in the gravity direction and is positioned at the upper side from the imaginary line 83 extending in line with the inlet side ends of the tubes 21. That is, two configurations are employed, but it is also possible to employ only one. In these cases as well, in the same way as the present embodiment, the area ratio is preferably made 35% or more.

Fourth Embodiment

FIG. 11 is a cross-sectional view of the heating-use heat exchanger 2 in the present embodiment. FIG. 11 is a view seen from the same direction as FIG. 2.
In the present embodiment, unlike the first to third embodiments, the vehicle mounted posture of the heating-use heat exchanger 2 is made a posture where the air outflow/inflow surfaces are parallel to the vertical direction. That is, the heating-use heat exchanger 2 is held in the air-conditioning case in an orientation with longitudinal directions of the tubes 11, 21 parallel to the vertical direction.
In the second heater core 20, part 91 of the wall forming the inlet side tank part 22 bulges outward from the other parts. Due to this bulged part 91, a liquid storage part 72 where the high temperature cooling water is stored is formed. Note that, the liquid storage part 72 of the present embodiment is also a region of the inlet side tank part 22 above the inlet side ends 21 a of the tubes 21.
Specifically, the inlet side tank part 22, while not shown, is comprised of a core plate in which the tubes 21 are inserted and a tank body joined together. Part 91 of the core plate of the wall of the upper side forming the inlet side tank part 22 bulges to the outside.
Further, in the present embodiment as well, the positional relationship between the cooling water inlet 20 a and the tubes 21 in the inlet side tank part 22 is as follows:
That is, as shown in FIG. 11, part of the cooling water inlet 20 a (non-hatched region in FIG. 11) is positioned below the inlet side ends (bottom end faces) 21 a of the tubes 21. Further, part of the cooling water inlet 20 a (hatched region in FIG. 11) is positioned outside from between two imaginary lines 81, 82 drawn from the tube inside walls 21 b at the inlet side ends 21 a of the tubes 21 in parallel in the gravity direction.
Therefore, in the present embodiment as well, part of the cooling water inlet 20 a is positioned other than right under the inlets of the tubes 21, so the high temperature cooling water flowing in from the cooling water inlet 20 a can be reliably guided to the liquid storage part 72. Further, it is possible to run high temperature cooling water from this liquid storage part 72 to the plurality of tubes 21, so it is possible to reduce the temperature difference in the vehicle left-right direction of the cooling water flowing through the heat exchange core part and possible to reduce the temperature difference in the vehicle left-right direction occurring in the air-conditioned air after passing through the heating-use heat exchanger 2. Note that, in the present embodiment as well, in the same way as the third embodiment, the area ratio is preferably made 35% or more.

Fifth Embodiment

FIG. 12 shows a cross-sectional view of the heating-use heat exchanger 2 in the present embodiment. FIG. 12 is a view seen from the same direction as FIG. 2.
The present embodiment changes the orientation of the heating-use heat exchanger 2 explained in the third embodiment, in the same way as the fourth embodiment, to an orientation in which the longitudinal direction of the tubes 11, 21 is parallel to the vertical direction. However, in the present embodiment, the inlet side tank part 22 of the second heater core 20 is not provided with the bulged part 91 in FIG. 11 explained in the fourth embodiment.
Specifically, as shown in FIG. 12, in the present embodiment as well, a liquid storage part 73 is formed in the inlet side tank part 22 in the region of above the inlet side ends 21 a of the tubes 21.
Further, when projecting the cooling water inlet 20 a in the longitudinal direction of the inlet side tank part 22, part of the cooling water inlet 20 a (non-hatched region in FIG. 12) is positioned below the inlet side ends (bottom end faces) 21 a of the tubes 21.
Further, part of the cooling water inlet 20 a (hatched region in FIG. 12 with hatching oriented from top left to bottom right) is positioned outside from between two imaginary lines 81, 82 drawn from the tube inside walls 21 b of the tubes 21 at the inlet side end 21 a in parallel in the gravity direction. Furthermore, part of the cooling water inlet 20 a (hatched region in FIG. 12 with hatching oriented from top right to bottom left) is positioned at the upper side from an imaginary line 83 extending in line with the inlet side end faces of the tubes 21.
Therefore, in the present embodiment as well, an effect similar to the third embodiment is exhibited. Note that, in the present embodiment as well, in the same way as the third embodiment, the area ratio is preferably made 35% or more.
Further, from the viewpoint of securing the volume of the liquid storage part 73, like in the later explained sixth embodiment, it is preferable to lengthen the insertion length of the tubes 21 which are inserted into the inlet side tank part 22 of the second heater core 20 compared with a general heat exchanger.

Sixth Embodiment

FIG. 13 is a cross-sectional view of a heating-use heat exchanger 2 in the present embodiment. FIG. 13 is a view seen from the same direction as FIG. 2.
As shown in FIG. 13, the heating-use heat exchanger 2 of the present embodiment, like the fourth and fifth embodiments, is held inside the air-conditioning case with the longitudinal directions of the tubes 11, 21 oriented parallel to the vertical direction.
Further, the insertion length 84 of the tubes 21 inserted into the inlet side tank part 22 of the second heater core 20 is longer than the insertion length 85 of the tubes 11 inserted into the inlet side tank part 12 of the first heater core 10. The “ insertion lengths 84, 85” are the lengths from the inside walls of the inlet side tank parts 22, 12 to the inlet side ends 21 a, 11 a of the tubes 21, 11. Due to this, the volume of the liquid storage part 74 which is formed in the region of the inlet side tank part 22 above the inlet side ends 21 a of the tubes 21 is increased.
In the present embodiment, in the positional relationship between the cooling water inlet 20 a and the tubes 21 at the inlet side tank part 22 of the second heater core 20, the majority of the cooling water inlet 20 a (hatched region in FIG. 13) is positioned at the upper side from the imaginary line 83 extending in line with the inlet side ends (inlet side end faces) 21 a of the tubes drawn parallel in the horizontal direction. Here, the majority of the cooling water inlet 20 a, like the explanation in the third embodiment, preferably has an area ratio of 35% or more.
Note that, like in the present embodiment, when the insertion length 84 of the tubes 21 which are inserted at the inlet side tank part 22 of the second heater core 20 is long, it is most preferable that the position 20 a 1 of the bottom end of the cooling water inlet 20 a be the same position as the inlet side ends 21 a of the tubes 21 or a position above the same. That is, it is most preferred that 100% of the area of the cooling water inlet 20 a overlap the tubes 21 in positional relationship. Due to this, it is possible to guide all of the high temperature cooling water which flows in from the cooling water inlet 20 a to the liquid storage part 74.

Seventh Embodiment

FIG. 14 is a front view of a heating-use heat exchanger in the present embodiment. The present embodiment changes the vehicle-mounted posture of the heating-use heat exchanger 2 shown in FIG. 12 explained in the fifth embodiment so that the air outflow/inflow surfaces are parallel to the vertical direction and further so that the inlet side tank part 22 is slanted upward in the gravity direction from the cooling water inlet 20 a down to the deep parts. The rest of the configuration is similar to that of the fifth embodiment.
Specifically, as shown in FIG. 14, the inlet side tank part 22 of the second heater core 20 has the cooling water inlet 20 a at one side end of the inlet side tank part 22 in the longitudinal direction (left-right direction). Cooling water flows from one side end of the inlet side tank part 22 in the longitudinal direction. Further, when viewing the second heater core 20 from the front side, the second heater core 20 is slanted in state so that the top wall of the inlet side tank part 22 is positioned with one end side of the inlet side tank part 22 in the longitudinal direction positioned upward in the gravity direction than the other end side in the longitudinal direction. At this time, the second heater core 20 has an angle formed by the top wall of the inlet side tank part 22 of the second heater core 20 and the horizontal direction as the slant angle θ2 and has a predetermined slant angle θ2.
Here, the “top wall” of the inlet side tank part 22 is the core plate when the inlet side tank part 22 is comprised of a core plate in which the tubes 21 are inserted and a tank body forming the tank part. Further, the predetermined slant angle θ2 may be made the same 1 to 1.5 degrees of the standard mold extraction gradient for mold extraction provided at the holding part of a heating-use heat exchanger of an air-conditioning case at the time of molding an air-conditioning case from plastic, but a size over this, for example, 3 degrees or more, is preferable. The second heater core 20 is mounted in the vehicle while held inside the air-conditioning case 51 in this slanted state.
In this way, by making the top wall of the inlet side tank part 22 slanted so that the deep part is positioned at the top from the cooling water inlet 20 a, it is possible to make the high temperature cooling water flowing through the liquid storage part travel along the top wall to enable it to be more easily guided to the deep side of the inlet side tank part 22 far from the cooling water inlet 20 a compared with the case where the top wall of the inlet side tank part 22 is horizontal. As a result, according to the present embodiment, compared with the fifth embodiment where the top wall of the inlet side tank part 22 is horizontal, it is possible to reduce the temperature difference in the vehicle left-right direction occurring in the air-conditioned air after passing through the heating-use heat exchanger 2.
FIG. 15 shows the results of evaluation of the relationship of the slant angle θ2 and the left-right vented air temperature difference. As will be understood from FIG. 15, in the range of the slant angle θ2 of 0 to 12 degrees, as the slant angle θ2 becomes larger, the left-right vented air temperature difference tends to fall, but in the range of the slant angle θ2 exceeding 12 degrees, as the slant angle θ2 becomes larger, the left-right vented air temperature difference tends to increase. Therefore, as the upper limit of the slant angle θ2, 19.5 degrees, the same as the left-right vented air temperature difference (absolute value) when the slant angle θ2 is 3 degrees, is preferable.
Note that, in the present embodiment, the heating-use heat exchanger 2 as a whole is slanted to make the angle formed by the top wall of the inlet side tank part 22 of the second heater core 20 and the horizontal direction a predetermined slant angle θ2, but instead of slanting the heating-use heat exchanger 2 as a whole, the shape of the inlet side tank part 22 of the second heater core 20 may be made a shape with the top wall of the inlet side tank part 22 slanted.
Further, the present embodiment is not limited to the fifth embodiment and can also be applied to the fourth and sixth embodiments where the air outflow/inflow surfaces are made parallel to the vertical direction and to the first to third embodiments where the air outflow/inflow surfaces are made slanted.

Eighth Embodiment

In the above embodiments, a liquid storage part is formed for storing high temperature cooling water at the inside of the inlet side tank part 22, but the present embodiment raises the flow velocity of the cooling water at the cooling water inlet side of the inlet side tank part 22.
FIG. 16 is a front view of the second heater core 20 in the present embodiment. As shown in FIG. 16, in the present embodiment, the cooling water inlet side at the inside of the inlet side tank part 22 is provided with, as a flow velocity raising means for raising the flow velocity of the cooling water flowing into the inlet side tank part 22, a plate-shaped member 92 which has a communication hole 91 with a smaller channel sectional area than the inlet side tank part 22.
Regarding the dimensions of the communication hole 91, for example, when the diameter of the inside of the inlet side tank part 22 is 16 mm, the diameter of the communication hole 91 is made 5 mm or less. In this way, the diameter of the communication hole 91 is made about ⅓ or less of the diameter of the inlet side tank part 22.
Due to this, according to the present embodiment, it is possible to raise the flow velocity of the cooling water after passing through the communication hole 91 compared with the flow velocity of the cooling water before passing through the communication hole 91.
As explained in the first embodiment, when the cooling water which flows into the second heater core 20 has a small flow rate, if the flow velocity of the cooling water which flows through the inlet side tank part 22 is low, the phenomenon ends up arising that it becomes hard for the cooling water to flow up to the tubes far from the cooling water inlet.
As opposed to this, according to the present embodiment, it is possible to raise the flow velocity of the cooling water which flows into the inlet side tank part 22, so compared with when not providing means for raising the flow velocity of the cooling water, it is possible to run cooling water deep into the inlet side tank part 22.
Accordingly, in the present embodiment as well, it is possible to reduce the temperature difference in the vehicle left-right direction of the cooling water flowing through the heat exchange core part 25 and possible to reduce the temperature difference in the vehicle left-right direction occurring in the air-conditioned air after passing through the heating-use heat exchanger 2.
Note that, in the present embodiment, the liquid storage parts explained in the first to the seventh embodiments are not formed, but it is also possible to form liquid storage parts in the same way as the first to the seventh embodiments. That is, the embodiment may be combined with the first to seventh embodiments. By combination, a higher advantageous effect is obtained.

Ninth Embodiment

FIG. 17 is a cross-sectional view of the heating-use heat exchanger 2 in the present embodiment. FIG. 17 is a view seen from the same direction as FIG. 2. In the present embodiment, compared with the heating-use heat exchanger 2 shown in FIG. 12 explained in the fifth embodiment, the opening area of the cooling water inlet 20 a of the second heater core 20 and the channel sectional area of the not shown cooling water introduction path are made smaller than those of the first heater core 10 so as to increase the flow velocity of the cooling water flowing through the inlet side tank part 22 of the second heater core 20. Here, the “cooling water introduction path” means the pipeline communicated with the cooling water inlet 20 a for guiding cooling water to the inlet side tank part 22.
For this reason, according to the present embodiment, compared with the case where the opening area of the cooling water inlet 20 a of the second heater core 20 and channel sectional area of the not shown the cooling water introduction path are equal to those of the first heater core 10, it is possible to run cooling water deep into the inlet side tank part 22.
Further, in the present embodiment, the channel sectional area of the inlet side tank part 22 of the second heater core 20 becomes smaller than the channel sectional area of the inlet side tank part 12 of the first heater core 10. Due to this as well, compared with the case where the channel sectional area of the inlet side tank part 22 of the second heater core 20 is equal to the channel sectional area of the inlet side tank part 12 of the first heater core 10, it is possible to raise the flow velocity of the cooling water flowing through the inlet side tank part 22 of the second heater core 20 and possible to run cooling water deep into the inlet side tank part 22.
In the present embodiment, the flow velocity of the cooling water which flows through the inlet side tank part 22 of the second heater core 20 is preferably raised so as to become equal to or more than the flow velocity of the cooling water which flows through the inlet side tank part 12 of the first heater core 10.
Note that, in the present embodiment, both the opening area of the cooling water inlet 20 a of the second heater core 20 and the channel sectional area of the not shown cooling water introduction path and the channel sectional area of the inlet side tank part 22 of the second heater core 20 are made smaller, but it is also possible to use just one to raise the flow velocity of the cooling water flowing through the inlet side tank part 22 of the second heater core 20. Further, in this way, the configuration for raising the flow velocity of the cooling water flowing through the inlet side tank part 22 of the second heater core 20 is not limited to the fifth embodiment. This may also be applied to the heating-use heat exchanger which are explained in the other embodiments.
In the present embodiment as well, part of the cooling water inlet 20 a (hatched region in FIG. 17) is positioned outside from between two imaginary lines 81, 82 drawn from the tube inside walls 21 b at the inlet side end 21 a of the tubes 21 in parallel in the gravity direction. For this reason, part of the high temperature cooling water which flows from the cooling water inlet 20 a can be guided to the liquid storage part 73.
Note that, in the present embodiment, by raising flow velocity of the cooling water which flows through the inlet side tank part 22 of the second heater core 20, it is possible to run cooling water deep into the inlet side tank part 22, so all of the cooling water inlet 20 a may be positioned right under the inlet of the tubes 21.
Further, in the present embodiment, the tank parts of the first heater core 10 and the second heater core 20 are made integral and the tubes 11, 21 of the first heater core 10 and the second heater core 20 are made integral to make the first heater core 10 and the second heater core 20. The tubes 11, 21 of the first heater core 10 and the second heater core 20 are connected, but the channels at the inside of the tubes 11, 21 are separately formed at the first heater core 10 and the second heater core 20. At this time, the fins of the first heater core 10 and the second heater core 20 may be made separate or joined.

10th Embodiment

FIG. 18A is a side view of a heating-use heat exchanger 2 in the present embodiment, while FIG. 18B is a front view of a second heater core 20 in FIG. 18A.
The present embodiment is the same as the first embodiment in the structure of the heating-use heat exchanger 2, but differs from the first embodiment in the up-down relationship of the heating-use heat exchanger 2. That is, the inlet side tank parts 12, 22 of the first and second heater cores 10, 20 are positioned at the upper side, while the exit side tank parts 13, 23 of the first and second heater cores 10, 20 are positioned at the lower side. Further, the heating-use heat exchanger 2 is held in the air-conditioning case with the longitudinal direction of the tubes 11, 21 oriented parallel to the vertical direction.
For this reason, in the present embodiment, when cooling water flows to the inlet side tank part 22 of the second heater core 20, as shown in FIG. 18B, cooling water higher in temperature than the cooling water inside of the exit side tank part 23 is, due to the effect of buoyancy, stored in the upper region 75 inside of the inlet side tank part 22 over the entire stacked direction of the plurality of tubes 21, then flows from this upper region 75 to the plurality of tubes. Further, the high temperature cooling water flows through the plurality of tubes 21 from the top toward the bottom. In this way, in the present embodiment, the upper region 75 inside the inlet side tank part 22 becomes the liquid storage part.
Accordingly, according to the present embodiment, it is possible to reduce the temperature difference in the vehicle left-right direction of the cooling water flowing through the heat exchange core part 25 and possible to reduce the temperature difference in the vehicle left-right direction occurring in the air-conditioned air after passing through the heating-use heat exchanger 2.

11th Embodiment

FIG. 19 is a side view of the heating-use heat exchanger 2 in the present embodiment. The present embodiment changes the up-down relationship of the first heater core 10 in the heating-use heat exchanger 2 shown in FIGS. 18A and 18B explained in the 10th embodiment. Specifically, as shown in FIG. 19, the first heater core 10 and the second heater core 20 have integral tank parts at the inlet side and the exit side whereby the two are formed integral in structure.
The inside of the upper side tank part 61 which is positioned at the upper side of the heating-use heat exchanger 2 is divided by the partition wall 62 into the exit side tank part 13 of the first heater core 10 and the inlet side tank part 22 of the second heater core 20.
Similarly, the inside of the bottom side tank part 63 positioned at the lower side of the heating-use heat exchanger 2 is divided by a partition wall 64 to the inlet side tank part 12 of the first heater core 10 and the exit side tank part 23 of the second heater core 20.
In the first heater core 10, the cooling water which flows in from the cooling water inlet 10 a which is provided at the inlet side tank part 12 positioned at the lower side flows through the tube 11 from the bottom to the top, while flows out from the cooling water exit 10 b which is provided at the exit side tank part 13 positioned at the upper side.
On the other hand, in the second heater core 20, the cooling water which flowed in from the cooling water inlet 20 a provided at the upper side flows through the tubes 21 from the top toward the bottom and flows out from the cooling water exit 20 b provided at the exit side tank part 23 provided at the lower side.
In the present embodiment as well, the inlet side tank part 22 of the second heater core 20 is positioned at the upper side, so advantageous effects similar to the eighth embodiment are obtained.
Furthermore, according to the present embodiment, the direction of flow of the cooling water inside of the first heater core 10 is opposite to the direction of flow of the cooling water inside of the second heater core 20, so it is possible to reduce the up-down temperature distribution after passing through the heating-use heat exchanger 2, that is, the temperature difference between the upper side and the lower side.

Other Embodiments

(1) In the above embodiments, the cooling water inlet 20 a provided at the inlet side tank part 22 of the second heater core 20 is an opening formed in the wall forming the inlet side tank part 22, but it is also possible to insert a pipe into this opening to obtain a state with a pipe sticking out from the inside wall of the inlet side tank part 22 to the inside of the inlet side tank part 22. In this case, the front end part of the pipe sticking out inside of the inlet side tank part 22 is an end opening of the cooling water introduction path which faces the inside of the inlet side tank part 22 and introduces cooling water to the inlet side tank part 22.
(2) In the above first to seventh and ninth to 11th embodiments, the cooling water inlet 20 a of the second heater core 20 is arranged at one end side of the inlet side tank part 22 in the vehicle left-right direction, but it need not be arranged at only one end side. It may be arranged at the two end sides or may be arranged at the center. Even with such an arrangement, according to the present invention, high temperature cooling water can be run into the tubes 21 positioned far from the cooling water inlet 20 a.
(3) In the above embodiments, the first heater core 10 and the second heater core 20 are integrally formed, but the first heater core 10 and the second heater core 20 may also be separate members.
Furthermore, in the above embodiments, the orientation of the flow of cooling water inside the first heater core 10 is the same down-to-up orientation as the second heater core 20, but may also be an up-to-down orientation opposite to the second heater core 20.
(4) In the above embodiments, the cooling water flowing out from the first cooling water exit 31 b of the engine 30 is only the cooling water cooling the cylinder head 31, but also may be cooling water comprised of the cooling water cooling the cylinder head 31 into which part of the cooling water cooling the cylinder block 32 is mixed. In short, it is sufficient that mainly cooling water cooling the cylinder head 31 flow out from the first cooling water exit 31 b of the engine 30.
Similarly, the cooling water flowing out from the second cooling water exit 32 b of the engine 30 is only the cooling water cooling the cylinder block 32, but may also be cooling water comprised of the cooling water cooling the cylinder block 32 into which part of the cooling water cooling the cylinder head 31 is mixed. In short, the cooling water cooling the cylinder block 32 mainly flows out from the second cooling water exit 32 b of the engine 30. It is sufficient that the cooling water which flows out from the second cooling water exit 32 b be higher in temperature than the cooling water flowing out from the first cooling water exit 31 b.
However, the cooling water flowing out from the second cooling water exit 32 b of the engine 30 is made a higher temperature than the case of the entire cooling water after cooling the cylinder head 31 and cooling water after cooling the cylinder block 32 mixed together. Due to this, compared with the case of mixing the entire amounts of the two flows of cooling water, it is possible to make higher temperature cooling water flow out from the engine 30.
(5) In the above embodiments, the cooling water which flows into the second heater core 20 is just the cooling water flowing out from the second cooling water exit 32 b of the engine 30, but part of the cooling water flowing out from the first cooling water exit 31 b may also be mixed in.
In short, it is sufficient that mainly cooling water flowing out from the second cooling water exit 32 b and higher in temperature than the cooling water flowing into the first heater core 10 flow into the second heater core 20. However, the cooling water which flows into the second heater core 20 becomes higher in temperature than the average temperature when mixing the entire amounts of the cooling water which flows out from the second cooling water exit 32 b and the cooling water which flows out from the first cooling water exit 31 b. Due to this, compared with when mixing the entire amounts of the two flows of cooling water, the air temperature after heating at the second heater core 20 can be raised.
(6) In the above embodiments, the first heater core 10 uses the cooling water after cooling the cylinder head as the heat source, while the second heater core 20 uses the cooling water after cooling the cylinder block as the heat source, but the first heater core 10 and the second heater core 20 may also use other liquids as the heat sources. When the first heater core 10 uses a first liquid as a heat source and the second heater core 20 uses a second liquid with a higher temperature and smaller flow rate than the first liquid as a heat source, the present invention can be applied.
For example, in a vehicular air-conditioning system which is mounted in a hybrid vehicle, it is possible to use a cooling solution of an inverter or other electric device as the first liquid and use a cooling solution of the engine as the second liquid. Further, for example, in a vehicular air-conditioning system which is mounted in an electric vehicle, it is possible to use a cooling solution of an inverter or other electric device as the first liquid and use a high temperature liquid heated by the electric heater or other heating means as the second liquid. In this way, the vehicular air-conditioning system of the present invention can be applied to vehicles other than hybrid vehicles as well.
(7) The above embodiments may be combined in a workable range.
While the invention has been described by reference to specific embodiments chosen for purposes of illustration, it should be apparent that numerous modifications could be made thereto by those skilled in the art without departing from the basic concept and scope of the invention.

Claims

1. A vehicular air-conditioning system comprising a heating-use heat exchanger which uses a first liquid and a second liquid with a higher temperature and smaller flow rate than said first liquid as heat sources to heat air blown into a passenger compartment, wherein

said heating-use heat exchanger comprises a first heat exchange part which exchanges heat between said first liquid and said blown air, and a second heat exchange part which exchanges heat between said second liquid and said blown air which was heated by said first heat exchange part,

said second heat exchange part comprises a plurality of tubes stacked together, an inlet side tank part which is connected to first end sides of said plurality of tubes in the longitudinal direction and which forms a liquid inlet side, and an exit side tank part which is connected to the other end sides of the plurality of tubes in the longitudinal direction and which forms a liquid exit side,

said second heat exchange part is held in an air-conditioning case so that said inlet side tank part is positioned at a lower side in a gravity direction and so that said exit side tank part is positioned at an upper side in a gravity direction, and

said second heat exchange part is configured to store the second liquid which flows into said inlet side tank part and which is higher in temperature than the liquid inside said exit side tank part in liquid storage parts in said inlet side tank part across the entire stacked direction of said plurality of tubes, then release it to said plurality of tubes.

2. A vehicular air-conditioning system as set forth in claim 1, wherein

said second heat exchange part is mounted in a vehicle while held in said air-conditioning case in a state so that, when viewing the second heat exchange part from the side, the angle formed by the longitudinal direction of said tubes and the vertical direction forms an acute angle, and

said liquid storage part is formed inside said inlet side tank part in a region above the inlet side end of said tube by making said second heat exchange part slanted.

3. A vehicular air-conditioning system as set forth in claim 1, wherein said liquid storage part is formed by making part of the wall forming said inlet side tank part bulge outside from the other parts.

4. A vehicular air-conditioning system as set forth in claim 1, wherein

said first heat exchange part comprises a plurality of tubes stacked together, an inlet side tank part which is connected to first end sides of said plurality of tubes in the longitudinal direction and which forms a liquid inlet side, and an exit side tank part which is connected to other end sides of the plurality of tubes in the longitudinal direction and which forms a liquid exit side,

an insertion length of said tubes which are inserted inside of said inlet side tank part of the second heat exchange part is longer than an insertion length of said tubes which are inserted into said inlet side tank part of said first heat exchange part, and

said liquid storage part is formed inside said inlet side tank part of said second heat exchange part in a region above inlet side ends of said tubes in the gravity direction.

5. A vehicular air-conditioning system as set forth in claim 1, wherein

when projecting an end opening of a liquid introduction path introducing said second liquid to said inlet side tank part of said second heat exchange part in a longitudinal direction of said inlet side tank part, at least part of the end opening of said liquid introduction path is positioned other than right under the inlets of said tubes in the gravity direction.

6. A vehicular air-conditioning system as set forth in claim 5, wherein at least part of the end opening of said liquid introduction path is positioned outside from between two imaginary lines which are drawn from the inside walls of said tubes at the inlet side ends of said tubes in parallel in the gravity direction.

7. A vehicular air-conditioning system as set forth in claim 5, wherein at least part of the end opening of said liquid introduction path is positioned at an upper side from an imaginary line extending in line with the inlet side end faces of said tubes.

8. A vehicular air-conditioning system as set forth in claim 5, wherein a part of 35% or more of the total area of the end opening of said liquid introduction path is positioned other than right under the inlets of said tubes in the gravity direction.

9. A vehicular air-conditioning system as set forth in claim 1, wherein said second heat exchange part is mounted in a vehicle while held in said air-conditioning case in a slanted state so that said second liquid flows from one end side of said inlet side tank part in a longitudinal direction thereof and so that a top wall of said inlet side tank part is positioned with one end side of said inlet side tank part in the longitudinal direction upward in the gravity direction compared with the other end side.

10. A vehicular air-conditioning system as set forth in claim 1, wherein inside said inlet side tank part of said the second heat exchange part, a flow velocity raising means is provided for making the flow velocity of the second liquid flowing to said inlet side tank part rise.

11. A vehicular air-conditioning system as set forth in claim 1, wherein

said first heat exchange part comprises a

plurality of tubes stacked together, an inlet side tank part which is connected to first end sides of said plurality of tubes in the longitudinal direction thereof and which forms a liquid inlet side, and an exit side tank part which is connected to other end sides of the plurality of tubes in the longitudinal direction and which forms a liquid exit side, and

a channel sectional area of the inlet side tank part of the second heat exchange part is smaller than the channel sectional area of the inlet side tank part of said first heat exchange part.

12. A vehicular air-conditioning system as set forth in claim 1, wherein

said first heat exchange part comprises a plurality of tubes stacked together, an inlet side tank part which is connected to first end side's of said plurality of tubes in a longitudinal direction thereof and which forms a liquid inlet side, and an exit side tank part which is connected to other end sides of the plurality of tubes in the longitudinal direction and which forms a liquid exit side, and

a channel sectional area of a liquid introduction path which introduces said second liquid to said inlet side tank part of the second heat exchange part is smaller than a channel sectional area of a liquid introduction path which introduces said first liquid to the inlet side tank part of said first heat exchange part.

13. A vehicular air-conditioning system comprising a heating-use heat exchanger which uses a first liquid and a second liquid with a higher temperature and smaller flow rate than said first liquid as heat sources to heat air blown into a passenger compartment, wherein

said heating-use heat exchanger comprises a first heat exchange part which exchanges heat between said first liquid and said blown air, and a second heat exchange part which exchanges heat between said second

liquid and said blown air which was heated by said first heat exchange part,

said second heat exchange part comprises a plurality of tubes stacked together, an inlet side tank part which is connected to first end sides of said plurality of tubes in a longitudinal direction thereof and which forms a liquid inlet side, and an exit side tank part which is connected to the other end sides of the plurality of tubes in the longitudinal direction and which forms a liquid exit side,

inside of said inlet side tank part, a flow velocity raising means is provided to raise the flow velocity of the second liquid which flows into said inlet side tank part.