Heat exchange – With timer – programmer – time delay – or condition responsive... – Having heating and cooling capability
Reexamination Certificate
2000-11-22
2002-11-12
Ciric, Ljiljana (Department: 3743)
Heat exchange
With timer, programmer, time delay, or condition responsive...
Having heating and cooling capability
C165S042000, C062S285000, C062S291000
Reexamination Certificate
active
06478083
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to an automotive air conditioner, and more particularly to an automotive air conditioning unit which comprises generally a casing defining therein an air passage with air inlet and outlet openings, an evaporator installed in an upstream portion of the air passage and a heater installed in a downstream portion of the air passage, an air intake unit connected to the air inlet opening of the air passage and an electric blower installed in the air intake unit for producing an air flow directed toward the air outlet opening through the air passage.
2. Description of Prior Art
In order to clarify the task of the present invention, two known automotive air conditioning units will be described with reference to
FIGS. 21 and 22
of the accompanying drawings.
In
FIG. 21
, one known automotive air conditioning unit
3
is shown, which is constructed compact in size for providing front passengers with a larger foot space. The unit
3
generally comprises a casing
6
, an evaporator
1
installed in a lower portion of an interior of the casing
6
and a heater
2
installed in a middle portion of the interior. Both the evaporator
1
and the heater
2
are inclined for a compact construction of the unit
3
. The casing
6
is formed at a lower part of a side wall thereof with a generally rectangular air inlet opening
4
through which air from an air intake unit (not shown) is introduced into a triangular space provided below the evaporator
1
. Between the evaporator
1
and the heater
2
, there is arranged a pivot door
5
which controls the ratio between the amount of air directed toward an air mixing chamber AM through the heater
2
and the amount of air directed toward the air mixing chamber AMC bypassing the heater
2
.
In
FIG. 22
, the other known automotive air conditioning unit
3
′ is shown, which is similar to the above-mentioned unit
3
. However, in the unit
3
′ of this drawing, a slide door
7
is used in place of the above-mentioned pivot door
5
. Due to the nature of the slide door
7
, compactness of the unit
3
′ is much assured as compared with that of the unit
3
of FIG.
21
.
However, in the above-mentioned known units
3
and
3
′, under operation, the triangular space defined below the evaporator
1
is subjected to uneven pressure distribution due to the inclined arrangement of the evaporator
1
and the rectangular shape of the air inlet opening
4
. The uneven pressure distribution brings about uneven air flow throughout the air passing area of the evaporator
1
and thus lowers the performance of the same.
The reason of the uneven air flow through the evaporator
1
will be briefly described with reference to
FIGS. 23 and 24
.
FIG. 23
is a plan view of the lower portion of the unit
3
or
3
′. That is, due to unbalanced air flow rate between larger and smaller areas of the triangular air inlet opening
4
and unbalanced air flow resistance in the triangular space between one side facing the larger area of the inlet opening
4
and the other side facing the smaller area of the same, there is produced an air swirl “S” at a central portion of the space which causes a pressure drop at such portion. Thus, smoothed air flow is not carried out at a central portion of the evaporator
1
. Furthermore, as is seen from
FIG. 23
, the air flow passing through the larger part “A” of the air inlet opening
4
is subjected to a pressure increase each time it collides against walls “B” and “C” of the case
6
, and finally, the pressure is much increased at the point “D” where it collides against the other air flow passing through the smaller part “E” of the opening
4
.
FIG. 24
is a graph depicting the manner of the air flow through the evaporator
1
with respect to the positions “A” to “E”. Pressurized areas are indicated by a shadow. As is seen from this graph, increased air flow appears around an area from the position “B” to the position “C” and around the position “D” and poor air flow appears at the other areas, which causes an uneven air flow through the evaporator
1
and thus lowers the performance of the same.
Usually, as is seen from
FIG. 23
, a drain pipe
9
is provided at a front wall of the casing
6
, which communicates the triangular space of the casing
6
and the interior of the engine room. Thus, under operation of the air conditioner, water drops produced when moisture touches the cold outer surface of the evaporator
1
are led into the engine room. However, due to generation of the air swirl “S” in the space, the water:drops or water is not smoothly drained to the engine room through the drain pipe
9
. In a worst case, the water drops or water is forced to flow backward toward the air intake unit under a certain running of an associated motor vehicle. This may bring about a trouble of the electric blower in the air intake unit.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an automotive air conditioning unit which is free of the above-mentioned drawbacks.
A main object of the present invention is to provide an automotive air conditioning unit which can suppress the undesirable backflow of water drop or water toward the air inlet opening.
A second object of the present invention is to provide an automotive air conditioning unit which allows an even air flow throughout the air passing area of the evaporator even when the evaporator is inclined and the air inlet opening is generally triangular in shape.
According to a first aspect of the present invention, there is provided an air conditioning unit which comprises a casing having air inlet and outlet openings which are connected through an air flow passage defined in the casing, the casing including a bottom surface in the vicinity of the air inlet opening; an evaporator arranged in the air flow passage; a heater arranged in the air flow passage at a position downstream of the evaporator; an air flow control door for controlling a ratio between an air amount flowing in a heater-bypassing passage which extends from the evaporator to the air outlet opening bypassing the heater and an air amount flowing in a heater-passing passage which extends from the evaporator to the air outlet opening through the heater; a water guide groove provided at the bottom surface of the casing at a position opposite to the position where the air inlet opening is provided; a drain pipe held by the casing and connected to the water guide groove; and a plurality of water backflow obstruction projections formed on the bottom surface in an area defined between the water guide groove and the air inlet opening, each projection being shaped and oriented so as to obstruct a flow of water in a direction from the water guide groove toward the air inlet opening.
According to a second aspect of the present invention, there is provided an air conditioning unit which comprises a casing having air inlet and outlet openings which are connected through an air flow passage defined in the casing, the casing including a bottom surface in the vicinity of the air inlet opening, the air inlet opening being generally triangular in shape so that the height of one side of the air inlet opening is greater than that of the other side of the same; an evaporator inclined and arranged in the air flow passage; a heater inclined and arranged in the air flow passage at a position downstream of the evaporator; an air flow control door for controlling a rate between an air amount flowing in a heater-bypassing passage which extends from the evaporator to the air outlet opening bypassing the heater and an air amount flowing in a heater-passing passage which extends from the evaporator to the air outlet opening through the heater; a water guide groove provided at the bottom surface of the casing at a position opposite to the position where the air inlet opening is provided, the water guide groove having a slanted bottom; a drain pipe held by the casing and connected to a lower portion of the
Kato Osamu
Nanba Yoshiaki
Noda Yoshitoshi
Sawano Kenichiro
Takasaki Morihiro
Calsonic Kansei Corporation
Ciric Ljiljana
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