U.S. patent application number 11/236757 was filed with the patent office on 2006-04-06 for heat storage tank with improved heat insulating performance.
This patent application is currently assigned to DENSO Corporation. Invention is credited to Masao Nishimura, Katsunori Uchimura.
Application Number | 20060070589 11/236757 |
Document ID | / |
Family ID | 36124310 |
Filed Date | 2006-04-06 |
United States Patent
Application |
20060070589 |
Kind Code |
A1 |
Uchimura; Katsunori ; et
al. |
April 6, 2006 |
Heat storage tank with improved heat insulating performance
Abstract
A heat storage tank, comprises an inner cylinder 81 having a
storage section 811 for storing liquid, an opening 812 at a lower
position of the storage section 811 and a body 84 in which a liquid
inflow channel 841 and a liquid outflow channel 842 are formed. The
body blocks the opening 812. When the inner diameter of the inner
cylinder 81 is referred to as a tank inner diameter D and the
vertical length of the storage section 811 is referred to as a tank
height H, D/H.ltoreq.0.5 holds. Therefore, the storage section 811
is elongated in the vertical direction and the distance between the
body 84, which is a main heat radiating portion, and the high
temperature water region is increased and, as a result, the high
temperature water region is extended in the vertical direction.
Inventors: |
Uchimura; Katsunori;
(Takahama-city, JP) ; Nishimura; Masao;
(Anjo-city, JP) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Assignee: |
DENSO Corporation
Kariya-city
JP
|
Family ID: |
36124310 |
Appl. No.: |
11/236757 |
Filed: |
September 27, 2005 |
Current U.S.
Class: |
123/41.14 |
Current CPC
Class: |
Y02E 60/142 20130101;
F01P 2011/205 20130101; F28F 2270/00 20130101; F28D 20/0034
20130101; F01P 11/20 20130101; Y02E 60/14 20130101 |
Class at
Publication: |
123/041.14 |
International
Class: |
F01P 11/02 20060101
F01P011/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 1, 2004 |
JP |
2004-290113 |
Claims
1. A heat storage tank comprising: an inner cylinder having a
storage section for storing liquid and an opening at a lower
position of the storage section; an outer cylinder accommodating
the inner cylinder therein and forming a thermally insulated space
between the inner cylinder and the outer cylinder; and a body in
which a liquid inflow channel and a liquid outflow channel for
causing the storage section to be communicated with an outside are
formed, the body blocking the opening, wherein an inner diameter of
the inner cylinder is referred to as a tank inner diameter D, a
length of the storage section in a vertical direction is referred
to as a tank height H in the heat storage tank in which the storage
section is a columnar space extending in the vertical direction,
and a ratio D/H satisfies the following: D/H.ltoreq.0.5.
2. The heat storage tank as set forth in claim 1, mounted in a
vehicle having a water-cooled internal combustion engine that is
cooled by cooling water, wherein liquid stored in the storage
section is cooling water that has risen in temperature after
cooling the water-cooled internal combustion engine.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a heat storage tank for
thermally insulating and storing a liquid and is effectively
applied, particularly, to a cooling device of a water-cooled
engine.
[0003] 2. Description of the Related Art
[0004] Conventionally, a system in which a heat storage tank
thermally insulates and stores high temperature engine cooling
water in it and then the thermally insulated cooling water is used
for promoting warm-up of an engine when the engine is started next
time (at a cold start) by circulating the thermally insulated
cooling water into the engine, or is used for immediately heating a
vehicle compartment by supplying the thermally insulated cooling
water to the heater core of a heating device of a vehicle is known
(for example, refer to Patent document 1).
[0005] [Patent Document 1]
[0006] Japanese Unexamined Patent Publication (Kokai) No.
10-71840
[0007] Then, the heat insulation performance of a heat storage tank
is particularly regarded as an important factor and a further
improvement of the heat insulation performance is required.
SUMMARY OF THE INVENTION
[0008] The above-mentioned point being taken into account, the
object of the present invention is to improve the heat insulation
performance of a heat storage tank.
[0009] In order to attain the above-mentioned object, a heat
storage tank according to a first aspect of the present invention
is characterized by comprising an inner cylinder (81) having a
storage section (811) for storing liquid and an opening (812) at a
lower position of the storage section (811), an outer cylinder (82)
accommodating the inner cylinder (81) therein and forming a
thermally insulated space (83) between the inner cylinder (81) and
itself, and a body (84) in which a liquid inflow channel (841) and
a liquid outflow channel (842) for causing the storage section
(811) to be communicated with the outside are formed and which
blocks the opening (812), wherein if it is assumed that the inner
diameter of the inner cylinder (81) is referred to as a tank inner
diameter D and the length of the storage section (811) in the
vertical direction is referred to as a tank height H in the heat
storage tank in which the storage section (811) is a columnar space
extending in the vertical direction, D/H.ltoreq.0.5 holds.
[0010] According to this, as shown in FIG. 3, in the region where
D/H.ltoreq.0.5 holds, the temperature of the water after being
stored is high and a high heat-insulation performance can be
obtained. This is because the storage section is elongated in the
vertical direction and the distance between the body, which is a
main heat radiating portion, and the high temperature water region
(in the vicinity of the top end of the storage section) is
increased and therefore the high temperature water region is
extended in the vertical direction.
[0011] When the inner diameter of the opening and the capacity of
the storage section are kept constant, as D/H is reduced, the tank
inner diameter D is reduced and the difference in dimension between
the tank inner diameter D and the inner diameter of the opening is
reduced, therefore, the draw manufacturing performance of the inner
cylinder is enhanced and it is possible to integrally form the
inner cylinder by, for example, a spinning process.
[0012] In a second aspect according to the above-mentioned first
aspect, it is possible to use a heat storage tank for storing
cooling water that has risen in temperature after cooling a
water-cooled internal combustion engine (1) for a vehicle.
[0013] The symbols in the parenthesis attached to each means
described above indicate a correspondence with a specific means in
the embodiments to be described later.
[0014] The present invention may be more fully understood from the
description of the preferred embodiments of the invention set forth
below, together with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In the drawings:
[0016] FIG. 1 is a schematic diagram of a cooling device for a
water-cooled engine using a heat storage tank according to an
embodiment of the present invention.
[0017] FIG. 2 is a section view of the heat storage tank in FIG.
1.
[0018] FIG. 3 is a diagram showing a relationship between the ratio
(D/H) of the tank inner diameter to the tank height and the heat
insulation performance of the heat storage tank.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] An embodiment of the present invention is explained below.
FIG. 1 is a schematic diagram of a cooling device for a
water-cooled engine using a heat storage tank according to an
embodiment and FIG. 2 is a sectional view of the heat storage tank
in FIG. 1.
[0020] In FIG. 1, the cooling device cools cooling water that has
risen in temperature after cooling a water-cooled internal
combustion engine (hereinafter, referred to as an engine) 1 of a
vehicle, not shown, through a radiator 2, and comprises a main
cooling water circuit 3 for causing cooling water to flow between
the engine 1 and the radiator 2 and an electric water pump 4 for
generating a cooling water flow.
[0021] A bypass circuit 5 for causing cooling water to flow while
bypassing the radiator 2 is connected in parallel with the main
cooling water circuit 3. A thermostat 6 provided at the connection
point of the main cooling water circuit 3 and the bypass circuit 5
carries out switching control between a case where the cooling
water is caused to flow through the bypass circuit 5 and a case
where the cooling water is caused to flow through the radiator 2.
By the way, switching between the two circuits 3 and 5 is normally
controlled such that the cooling water flows through the radiator 2
when the cooling water temperature is equal to or higher than about
80.degree. C. and the cooling water flows through the bypass
circuit 5 when the temperature is lower than about 80.degree.
C.
[0022] A sub-cooling-water circuit 7 for causing the cooling water
to flow while bypassing the main cooling water circuit 3 and the
bypass circuit 5 is connected in parallel to the main cooling water
circuit 3 and the bypass circuit 5. The sub-cooling-water circuit 7
is provided with a heat storage tank 8 for thermally insulating
(and storing) heat of cooling water and an electromagnetic
opening/closing valve 9 for opening and closing the sub cooling
water circuit 7.
[0023] Next, the heat storage tank 8 is explained using FIG. 2.
[0024] The heat storage tank 8 comprises an inner cylinder 81 and
an outer cylinder 82 made of a material excellent in corrosion
resistance such as stainless and formed into a bottomed cylindrical
shape. The heat storage tank 8 has a structure in which end
portions 8a of the inner cylinder 81 and the outer cylinder 82 are
welded in a state in which the inner cylinder 81 is accommodated
within the outer cylinder 82, and a thermally insulated space 83
substantially in a vacuum state is formed between the inner
cylinder 81 and the outer cylinder 82. By the way, the inner
cylinder 81 is integrally formed by a spinning process.
[0025] Within the inner cylinder 81, a storage section 811 for
storing cooling water is formed and the storage section 811 forms a
columnar space extending in the vertical direction. Into a small
diameter opening 812 and a large diameter opening 813 of the inner
cylinder 81 located at the lower portion of the storage section
811, a body 84 made of resin that blocks both the openings 812 and
813 is inserted. By the way, a female screw formed in the large
diameter opening 813 of the inner cylinder 81 and a male screw
formed at the body 84 are screwed with each other and, thereby, the
inner cylinder 81 and the body 84 are joined together.
[0026] Between the inner cylinder 81 and the body 84, a ring-shaped
rubber packing 85 for sealing between the inner cylinder 81 and the
body 84 is arranged. In more detail, the packing 85 is arranged at
the boundary between the small diameter opening 812 and the large
diameter opening 813 in the inner cylinder 81.
[0027] In the body 84, a cooling water inflow channel 841 that
causes the sub cooling water circuit 7 on the opening/closing valve
9 side to be communicated with the storage section 811 is formed.
The end portion of the cooling water inflow channel 841 on the
storage section 811 side opens at the position in the vicinity of
the small diameter opening 812 of the inner cylinder 81, that is,
at the lower position of the storage section 811. The cooling water
inflow channel 841 corresponds to the liquid inflow channel of the
present invention.
[0028] To the end portion of the body 84 on the storage section 811
side, a pipe 10 is attached. Then, through an in-body
cooling-water-outflow channel 842 formed in the body 84 and an
in-pipe cooling-water-outflow channel 101 formed in the pipe 10,
the sub-cooling-water circuit 7 on the water pump 4 side and the
storage section 811 are communicated with each other. The end
portion of the in-pipe cooling water outflow channel 101 on the
storage section 811 side opens at the position in the vicinity of
the top wall of the inner cylinder 81, that is, at the position in
the vicinity of the top end of the storage section 811. The in-body
cooling-water-outflow channel 842 corresponds to the liquid outflow
channel of the present invention.
[0029] To the end portion of the body 84 on the storage section 811
side, a mixture prevention plate 11 having a substantially cup-like
shape is attached so as to enclose the end portion of the cooling
water inflow channel 841 on the storage section 811 side. In the
mixture prevention plate 11, a plurality of outflow holes 111 are
formed and the cooling water that has flowed in from the
cooling-water-inflow channel 841 is guided to flow substantially
evenly to the storage section 811 side through the outflow holes
111.
[0030] An angle 12 is attached to the outer surface of the outer
cylinder 82 and the heat storage tank 8 is fixed to a vehicle by
means of this angle 12
[0031] Next, the operation of a cooling device having the
above-mentioned configuration is explained below.
[0032] When the temperature of the cooling water becomes high, due
to the operation of the engine 1, the opening/closing valve 9 is
opened and the high temperature cooling water is caused to flow
into the heat storage tank 8. After the engine stops, the high
temperature cooling water is thermally insulated and stored in the
heat storage tank 8.
[0033] Then, when the engine is started, the temperature of the
portion in the vicinity of the engine combustion chamber is raised
by circulating the cooling water thermally insulated and stored in
the heat storage tank 8 through the engine 1.
[0034] Specifically, immediately before the engine is started, the
water pump 4 is put into operation and the opening/closing valve 9
is opened. Due to this, the low temperature cooling water flows
into the storage section 811 of the heat storage tank 8 through the
sub-cooling-water circuit 7 and the cooling-water-inflow channel
841.
[0035] The cooling water that has flowed in pushes up the high
temperature cooling water thermally insulated and stored in the
storage section 811 and the high temperature cooling water
circulates to the engine 1 through the in-pipe cooling water
outflow channel 101, the in-body cooling water outflow channel 842,
and the sub cooling water circuit 7.
[0036] At this time, the low temperature cooling water flowing into
the storage section 811 is designed to push up the high temperature
cooling water stored in the storage section 811 evenly with respect
to the entire circumference due to the effect of the mixture
prevention plate 11. Therefore, the mixture of the low temperature
cooling water flowing in and the stored high temperature cooling
water is prevented and the high temperature cooling water is caused
to circulate to the engine 1.
[0037] Next, by using the ratio (D/H) between the inner diameter D
of the inner cylinder 81 (hereinafter, referred to as a tank inner
diameter) and the length H of the storage section 811 in the
vertical direction (hereinafter, referred to as a tank height) as a
parameter, the heat insulation performance of the heat storage tank
8 is evaluated. The distance from the top end of the storage
section 811, that is, from the top wall of the inner cylinder 81,
to the small diameter opening 812 corresponds to the tank height
H.
[0038] FIG. 3 shows the results of a study wherein the horizontal
axis represents the ratio (D/H) between the tank inner diameter D
and the tank height H. The vertical axis in FIG. 3 shows the
average temperature of the hot water in the heat storage tank 8
after the hot water at an initial temperature of 90.degree. C. is
thermally insulated in the heat storage tank 8 for 24 hours.
[0039] The tank inner diameter D of the evaluated heat storage tank
8 is set to a constant value, that is, 100 mm, and the inner
diameter of the small diameter opening 812 is also set to a
constant value, and the tank height H is changed.
[0040] As is obvious from FIG. 3, in the region in which
D/H.ltoreq.0.5 holds, the temperature of the hot water after
thermally insulated for 24 hours is high and high heat insulation
performance can be obtained. This is because the storage section
811 is elongated in the vertical direction and the distance between
the body 84, which is a main heat radiating portion, and the hot
water region (in the vicinity of the top end of the storage section
811) is increased and the hot water region is extended in the
vertical direction. The ratio D/H may be set in order to satisfy
several requirements for the heat storage tank such as an inner
capacity of water and a vertical height that may be limited for
installation of the storage tank on vehicles. In this aspect, the
heat storage tank may be designed to satisfy that the ratio D/H is
equal to or greater than 0.3. Instead, the ratio D/H may be set
equal to or greater than 0.35. Further, the ratio D/H may be set
equal to or greater than 0.4 in order to satisfy an installation
requirement. On the other hand, the ratio D/H may be set equal to
or less than 0.45. Instead, the ratio D/H may be set equal to or
less than 0.4 in order to improve hot water temperature.
[0041] While the invention has been described by reference to
specific embodiments chosen for the 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.
* * * * *