Internal-combustion engines – Cooling – Devices for cooling liquid by air flow
Reexamination Certificate
2002-02-04
2003-09-23
Yuen, Henry C. (Department: 3747)
Internal-combustion engines
Cooling
Devices for cooling liquid by air flow
Reexamination Certificate
active
06622668
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a construction machine equipped with an engine and a plurality of cooling units, in which some of the cooling units are disposed in parallel and cooled with a single cooling fan in order to enhance the cooling efficiency, reduce the leakage of operation noise, and facilitate the cooling of the cooling units.
BACKGROUND ART
Construction machines include, for example, a hydraulic shovel that performs a digging operation for a dam, a tunnel, a road, water supply and drainage, etc., or a dismantling operation for constructions, etc.
The hydraulic shovel is constructed of a lower travel body, an upper swivel body supported on the lower travel body so that it can swivel, and a working unit provided on the front portion of the upper swivel body.
The upper swivel body is usually provided with a driver's cab. However, there are cases where small hydraulic shovels have not a driver's cab but a driver's seat.
Furthermore, the frame of the swivel body is provided with an engine, a hydraulic pump, cooling units, batteries, control valves, a fuel tank, a working-oil tank, etc.
The construction machine performs various operations such as traveling by the lower travel body, swiveling by the upper swivel body, digging by the working unit, etc. These operations are performed by a hydraulic actuator, constructed of a hydraulic motor, a hydraulic cylinder, etc. As shown in
FIG. 11
, pressure oil is supplied to the hydraulic actuator by the hydraulic pump
05
that is driven by the engine
03
.
In addition, units, such as the engine
03
, radiator
06
, hydraulic pump
05
, and direction-switching valves for switching the direction of the pressure oil supplied from the hydraulic pump
05
, are disposed within the upper swivel body.
The upper swivel body is provided with an engine room
02
having a cover
01
. Within the engine room
02
, the engine
03
is provided, and the radiator
06
for cooling the engine
03
, an oil cooler
010
for cooling working oil, an intercooler
08
for cooling air which is supplied to the combustion chamber of the engine
03
, and a condenser
012
, are disposed.
The intercooler
08
, oil cooler
010
, radiator
06
, and condenser
012
constitute a first cooling unit group R which is used to cool working oil and cooling water. To expose the first cooling unit group R to cooling air and then cool the coolants of the first cooling unit group R, a cooling fan
014
is disposed. The cooling fan
014
is driven by the engine
03
.
The cover
01
that constitutes part of the engine room
02
is provided with outside-air introducing ports
01
a
for introducing the outside air, and exhaust ports
01
b
for discharging the introduced air. The introduced air cools the first cooling unit group Rand then the engine
03
, the hydraulic pump
05
, and the direction switching valves. Thereafter, the air that has reached high temperature is discharged from the exhaust ports
01
b
to the outside.
With this arrangement, cooling air is introduced through the outside-air introducing ports
01
a
. Within the engine room
02
, a flow of air occurs as indicated by arrows, cools the engine
02
, the hydraulic pump
05
, the direction switching valves, etc., and is discharged from the exhaust ports
01
b.
As shown in
FIG. 11
, with respect to the first cooling unit group R provided within the engine room
02
, the cooling air flows in the order of condenser
012
, intercooler
08
, oil cooler
010
, and radiator
06
from the upstream side.
The intercooler
08
is used for cooling air compressed by a supercharger
016
that increases the pressure of the fuel-air mixture in the engine
03
. Because of this, a filter unit
017
is provided on the exterior of the engine room
02
to prevent the entry of dust and dirt.
The supercharger
016
is used to compress introduced air by rotating the turbine with the energy of the exhaust gas of the engine
03
. Since the temperature of the introduced air rises due to adiabatic compression, it is necessary to cool the introduced air before it is supplied to the engine
03
, for the output of the engine
03
and purification of the exhaust gas.
The introduced air is cooled by the intercooler
08
, and is generally cooled to about 40 to 70° C. at the normal temperature.
Since the coolant of the intercooler
08
has to be cooled to a temperature lower than those of other heat exchangers, and the quantity of the radiant heat of the oil cooler
010
and the radiator
06
is relatively large, the intercooler
08
is generally disposed on the most upstream side of a flow of air, or on the upstream side from the radiator
06
.
Since the supercharger
016
must be disposed on a portion of the engine
03
, conduits
018
,
019
for circulating compressed air are connected between the supercharger
016
and the intercooler
08
and between the intercooler
08
and the engine
03
.
For the aforementioned reasons, the aforementioned heat exchange is performed in the order of condenser
12
, intercooler
08
, oil cooler
010
, and radiator
06
, and in order to enhance the cooling efficiency, the condenser
12
, the intercooler
08
, the oil cooler
010
, and the radiator
06
are disposed in close proximity to one another. However, in construction fields, dust and dirt tend to adhere to the condenser
012
, the intercooler
08
, the oil cooler
010
, and the radiator
06
. If dust and dirt adhere to the condenser
012
, the intercooler
08
, the oil cooler
010
, and the radiator
06
, the aforementioned various operations cannot be continued unless they are frequently cleaned.
In the case where the intercooler
08
, the oil cooler
010
, and the radiator
06
are disposed in the recited order, there are cases where, in a narrow space within the engine room
02
of the hydraulic shovel, particularly a narrow space within the engine room of a small hydraulic shovel, rotation of the oil cooler
010
becomes difficult. In the case where the intercooler
08
is disposed so as to face the oil cooler
010
or radiator
06
, the intercooler
08
becomes a hindrance and therefore the oil cooler
010
cannot be cleaned.
Hence, the radiator
06
or oil cooler
010
is made of a lightweight aluminum alloy so that it can be easily lifted upward. The radiator
06
or oil cooler
010
is first lifted upward to form an open space behind the intercooler
08
. Then, the intercooler
08
is cleaned, for example, with an air jet nozzle. The removed radiator
06
or oil cooler
010
is also cleaned, and is returned to the original position.
Because the air suction and exhaust tubes of the intercooler
08
are large in diameter and are generally fixed on the upper swivel body, the aforementioned operation becomes necessary.
In addition, in the conventional construction machine shown in
FIG. 11
, the first cooling unit group R, the engine
03
, and the hydraulic pump
05
are disposed in a cooling-air passage which is widely communicated through a core having the area of the wide cooling-air passage of the cooling units within the engine room
02
. Therefore, there is a fear that noise generated by the engine
03
and the cooling fan
014
will be transmitted from the wide area to the outside.
In the conventional construction machine, if the first cooling unit group R is not cleaned, the cooling fan
014
will be clogged by dust and dirt. As a result, the circulation of the cooling air for the first cooling unit group R is reduced and the cooling efficiency becomes low. Because of this, the performance of the construction machine cannot be sufficiently utilized. In addition, to clean the radiator
06
or oil cooler
010
, removing and installing the radiator
06
or oil cooler
010
require labor and time, resulting in a reduction in the operation efficiency. Furthermore, as described above, there is a fear that noise will be transmitted to the outside of the construction machine.
The present invention has been made in view of the problems mentioned above. Accordingly, it is the primary object of the present
Ali Hyder
Morrison & Foerster / LLP
Shin Caterpillar Mitsubishi Ltd.
Yuen Henry C.
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