Engine cooling air passage for construction equipment

Details Engine cooling air passage for construction equipment Engine cooling air passage for construction equipment

2001-01-10

2004-06-08

Fischmann, Bryan (Department: 3618)

Motor vehicles

Power

With means to guide and/or control air for power plant cooling

Reexamination Certificate

active

06745860

ABSTRACT:

This application claims the benefit of JP 2000-003629 filed Jan. 12, 2000.
TECHNICAL FIELD
The present invention relates to an engine cooling air passage for construction equipment.
BACKGROUND ART
Recently, due to environmental sensitivity, equipment causing less noise to the environment (hereinafter called ambient noise) is demanded also in construction equipment. For this reason, conventionally, the front and the back, the left and the right side, and the top and the bottom of the entire bodies of an engine, a cooling fan and a radiator in front of the engine are covered with partition walls or wall surfaces of the other devices in such a manner as to be wrapped with them, and thereby an engine room is constructed. A cooling air inlet port is provided at an upper partition wall in front of the radiator of the engine room, and a cooling air exhaust port is provided at an upper partition wall at the back of the engine room to thereby form an engine cooling air passage, whereby cooling air is taken in from an upper front portion of the engine room and is discharged to an upper rear portion thereof. The structure in which noises of a cooling fan and an engine are not directly released outside according to the above configuration is generally achieved.
However, as for an engine cooling air passage for construction equipment, there always exists a demand for the solution to eliminate the contradictory phenomena in these three items: securing sufficient opening areas for the inlet port and the exhaust port to obtain sufficient amount of engine cooling air; the resultant increase in engine noise released to the outside; and increase in the size of the engine room to prevent the noise release.
The above problems the solution to which is demanded are explained below by separating them into the cooling air inlet port side and the cooling air exhaust port side.
(1) In the cooling air inlet port, the inlet port is provided in the upper partition wall in front of the radiator of the engine room, whereby the engine room is substantially extended in front of the radiator, which results in the increase in size and becomes a disadvantage to small-sized construction equipment. However, since a space in front of the radiator serves as a noise-suppressing duct, noise release from the inlet port can be reduced to the practical level. Further, for example, Japanese Utility Model Laid-open No. 3-64121 discloses the means for reducing the extension in front of the radiator by 50 percent to secure the inlet amount of cooling air, which proves effective.
(2) As for the cooling air exhaust port, the exhaust port can be easily provided in the upper partition wall at the back of the engine room without increasing the size of the engine room. However, this results in direct opening of the upper portion of the engine room, whereby engine noise, and the noises of a power transducer such as a hydraulic pump, for example, are directly released from the exhaust port without being attenuated, thus making it impossible to reduce the noise.
As is generally known, even if one of two equal sound sources (in this case, the cooling air inlet port and the cooling air exhaust port) is reduced to zero, the noise reduction effect of only about 3 dB is obtained if the other one remains as it is. Consequently, in the above situation, the noise reduction effect of the cooling air inlet port is buried, and construction equipment with less noise is not provided. Hence, it is one of important issues to form an engine cooling air passage in which discharge of sufficient amount of cooling air is compatible with sufficient reduction in noise release.
The above issue will be explained with FIG.
17
and FIG.
18
.
FIG. 17
is a fragmentary perspective view of a hydraulic shovel having an engine room to which an engine cooling air passage according to a prior art is applied. In the hydraulic shovel, an upper revolving superstructure
2
is rotatably mounted at approximately a center of a top portion of the a base carrier
1
, and at an upper rear end of the upper revolving superstructure
2
, placed is a counterweight
3
, in front of which, placed are an engine room
4
, a hydraulic fluid tank
5
and a fuel tank
6
. At a front part of the upper revolving superstructure
2
, an operator's cab
7
is placed at a left side, and a working machine
8
is attached at approximately a center portion. In a top face of the engine room
4
, a cooling air inlet port
11
is provided at a left end portion of a vehicle body and a cooling air exhaust port
12
is provided at a right end portion of the vehicle body.
FIG. 18
is a fragmentary sectional top view of the engine room of
FIG. 17
, and
FIG. 19
is a fragmentary sectional side view of the engine room. It should be noted that the broken line arrow represents a vector of a cooling fan blown-off air, while the solid line arrow represents a flow of a cooling air in
FIGS. 18 and 19
, and the same thing will apply hereinafter.
In
FIGS. 18 and 19
, entire bodies of an engine
13
, an auxiliary pump
14
, a hydraulic pump
15
as a power transducer, a cooling fan
16
, a radiator
17
, an oil cooler
18
and an air conditioning condenser
19
are covered with a front partition wall
21
, a rear partition wall
22
, a left side partition wall
23
, a right side partition wall
24
, an upper partition wall
25
and a lower partition wall
26
to define the engine room
4
. The upper partition wall
25
is provided with the cooling air inlet port
11
in front of the radiator
17
and with the cooling air exhaust port
12
behind the engine
13
.
In
FIG. 18
, in order to exhaust sufficient amount of cooling air, it is necessary to reduce exhaust resistance (hereinafter, called back pressure). The first problem regarding this is the following point. Normally, the vectors of blown-off air from the cooling fan
16
have the property that they have higher speed as they are away from the center of the fan in a radial direction and they tend to spread in the radial direction due to centrifugal force. In the engine room
4
of a normal size as shown in
FIG. 18
, the flow of the cooling air cannot go along the aforesaid vectors of the blown-off air and is disturbed as shown by the solid line arrows, and thus it does not pass smoothly, whereby back pressure occurs. The second problem is as follows. The cooling air exhaust port
12
is opened at the position where an unobstructed view of the engine
13
and the hydraulic pump
15
being the noise sources can be obtained if the opening area is increased in order to reduce the back pressure occurring due to the resistance of the cooling air exhaust port
12
, and therefore the noise therefrom are directly released outside without being attenuated, thus providing less effect of reducing the ambient noise.
Hence, the art of providing the cooling air passage in which sufficient discharge of cooling air is compatible with sufficient reduction in noise release is always demanded.
As the fist prior art for solving the above problem, for example, Japanese Patent No. 2775037 discloses the art of a sound insulation housing having an inlet and discharge duct which is designed to attenuate inlet noise and exhaust noise. FIG.
20
and
FIG. 21
are explanatory views of the art disclosed in the same Patent,
FIG. 20
is a partially omitted fragmentary sectional top view of a hydraulic shovel to which the art of the sound insulation housing is applied, and
FIG. 21
is a perspective view of a counterweight of the hydraulic shovel.
In
FIG. 20
, an upper revolving superstructure
32
is rotatably mounted at approximately a center of an upper portion of a base carrier
31
, and a counterweight
33
is placed at a rear end portion of the upper revolving superstructure
32
. In front of the counterweight
33
, placed are an engine
34
, a hydraulic device
35
such as a hydraulic pump, engine cooling devices such as a cooling fan
16
and a radiator
17
. Further, an operator's cab
38
is placed at a left side of a front part of the upper revolving superstru

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