U.S. patent number RE30,333 [Application Number 06/007,094] was granted by the patent office on 1980-07-15 for ebullient cooled turbocharger bearing housing.
This patent grant is currently assigned to Caterpillar Tractor Co.. Invention is credited to Phillip B. Gordon, Jr., Keats E. Hunt.
United States Patent |
RE30,333 |
Gordon, Jr. , et
al. |
July 15, 1980 |
Ebullient cooled turbocharger bearing housing
Abstract
A turbocharged internal combustion engine system including a
liquid-cooled internal combustion engine, a heat exchanger for
cooling the liquid, a pump for pumping cooled liquid from the heat
exchanger to the engine, and a turbocharger including a rotary
turbine and a rotary compressor, a housing containing the turbine
and the compressor, a shaft interconnecting the turbine and the
compressor and bearings journalling the shaft within the housing
between the turbine and compressor. Exhaust gases from the engine
are directed through the turbine to drive the same and air from the
compressor is directed to the engine. A liquid passage is located
in the turbocharger housing and is operatively interposed between
the turbine and the bearing. The passage has a lower inlet and an
upper outlet and liquid coolant from the engine is directed to the
inlet. Coolant from the output is directed to the heat exchanger or
other suitable compartment in the engine coolant system so as to
allow flow while the engine is operating and under the following
conditions. Thermosiphoning of the coolant will occur through the
passage when the engine is not operative, resulting in ebullient
cooling of the housing immediately adjacent the bearings when the
engine is not operating. As a result, thermal damage to the
bearings is prevented and coking of the residual oil on the inside
walls of the housing is also prevented.
Inventors: |
Gordon, Jr.; Phillip B.
(Washington, IL), Hunt; Keats E. (Peoria, IL) |
Assignee: |
Caterpillar Tractor Co.
(Peoria, IL)
|
Family
ID: |
26676501 |
Appl.
No.: |
06/007,094 |
Filed: |
January 29, 1979 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
745743 |
Nov 29, 1976 |
04107927 |
Aug 22, 1978 |
|
|
Current U.S.
Class: |
60/605.1;
415/175; 417/407; 60/39.08 |
Current CPC
Class: |
F01D
25/125 (20130101); F02B 39/005 (20130101); F05D
2220/40 (20130101) |
Current International
Class: |
F01D
25/08 (20060101); F01D 25/08 (20060101); F01D
25/12 (20060101); F01D 25/12 (20060101); F02B
39/00 (20060101); F02B 39/00 (20060101); F02B
037/00 () |
Field of
Search: |
;60/39.08,605 ;184/6.11
;417/407 ;415/175,180 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Koczo; Michael
Attorney, Agent or Firm: Wegner, Stellman, McCord, Wiles
& Wood
Claims
What is claimed is:
1. In a turbocharged, internal combustion engine system, the
combination of:
a liquid cooled, internal combustion engine;
a heat exchanger for cooling the liquid from the engine;
a turbocharger including a rotary turbine and a rotary compressor,
housings containing the turbine and the compressor, a shaft
interconnecting the turbine and the compressor and bearings
journalling the shaft within the housing adjacent the turbine;
means for directing exhaust gases from said engine to said turbine
to drive the same;
means for directing air from said compressor to the engine;
a liquid passage in said housing operatively interposed between
said turbine and said bearings and having a lower inlet and an
upper outlet;
means for directing liquid coolant from said engine to said inlet;
and
means for directing coolant from said outlet to said heat exchanger
whereby thermosiphoning of said coolant through said passage will
occur when said engine is not operative and ebullient cooling of
said housing immediately adjacent said bearings will occur
.Iadd.due .Iaddend.to the presence of liquid in said passage to
thereby prevent excessive heat buildup in said housing even when
said engine is not operative and thereby prevent thermal damage to
said bearings.
2. The system of claim 1 further including an oil inlet and an oil
outlet in said housing and including an oil passage extending to
said bearings, liquid coolant in said passage cooling said bearings
to prevent the coking of the oil therein even when said engine is
nonoperative.
3. The system of claim 2 wherein said heat exchanger includes a
pressure seal and is operative to contain fluid under elevated
pressure during operation of said engine.
4. The system of claim 1 wherein said liquid passage comprises an
at least partially annular chamber disposed about said shaft. .[.5.
A turbocharger for use with a liquid cooled, internal combustion
engine comprising:
a housing including turbine and compressor chambers;
a shaft in said housing extending between and into said
chambers;
bearings in said housing adjacent said chambers and journalling
said shaft;
an impeller mounted on said shaft within said compressor
chamber;
a turbine wheel mounted on said shaft within said chamber;
an air inlet and an air outlet in said compressor chamber;
an engine exhaust inlet and an engine exhaust outlet in said
turbine chamber;
an annular or partly annular liquid coolant receiving chamber in
said housing about said shaft and between and sealed from said
turbine chamber and said adjacent bearings;
an upper liquid engine coolant outlet for said annular or partly
annular chamber;
a lower liquid engine coolant inlet for said chamber; and
lubricant passages separate from said chamber and coolant inlet and
outlet
and extending to said bearings..]. .[.6. A turbocharger for use
with a liquid cooled, internal combustion engine comprising:
a housing including turbine and compressor chambers;
a shaft in said housing extending between and into said
chambers;
bearings in said housing adjacent said chambers and journalling
said shaft;
an impeller mounted on said shaft within said compressor
chamber;
a turbine wheel mounted on said shaft within said turbine
chamber;
an air inlet and an air outlet in said compressor chamber;
an engine exhaust inlet and an engine exhaust outlet in said
turbine chamber;
an engine coolant receiving passage in said housing between said
turbine chamber and said adjacent bearings and in heat transfer
relation to but sealed from said turbine chamber;
at least one lower, liquid engine coolant inlet in said housing for
said passage;
at least one upper, liquid engine coolant outlet for said
passage;
lubricant passages in said housing extending to said bearings, said
lubricant passages being separate from said coolant passage;
and
at least one inlet and outlet in said housing for said lubricant
passages..].
Description
BACKGROUND OF THE INVENTION
This invention relates to turbochargers and internal combustion
engine systems including turbochargers.
Prior art of possible relevance includes commonly assigned U.S.
Pat. No. 3,740,170, issued June 19, 1973 to Miller; and the present
invention is an improvement on the invention disclosed therein.
Turbochargers are frequently employed in connection with internal
combustion engines for compressing combustion air prior to its use
by the engine. Typically, exhaust gases from the engine are
conveyed to the turbocharger to provide the motive force for
compression of the combustion air. As a consequence, the
turbocharger housings are subjected to elevated temperatures of the
exhaust gases requiring provision for the cooling of bearings to
prevent premature failure due to thermal deterioration.
The above identified Miller patent illustrates one such
construction wherein lubricating oil is directed to the bearing for
the bifold purpose of lubricating and cooling the same. The Miller
approach is quite satisfactory for its intended purpose in most
installations. However, where the pump for the oil is engine driven
and where the turbocharger runs excessively hot due to elevated
exhaust system temperature or is located in a cover for fire
insulation and/or noise suppression, premature bearing failure
and/or turbine end oil seal failure and/or coking of the oil in the
housing may nonetheless result.
In particular, once the engine is turned off, the lubricating oil
will no longer be directed to the bearings to cool the same. At the
same time, residual heat in the turbine section from exhaust gases
will be present and cannot readily escape the turbocharger
environment due to the fact that the turbocharger is enclosed in
such a cover or the exhaust temperature was so high at shutdown
that normal conduction overheats the bearings and seals. As a
consequence, the heat of the turbine section will flow to the
housing in the area of the bearings and seal and to the bearings
and cause coking of the lubricant remaining in the housing and on
the bearing surfaces which, in turn, will result in undesirable
premature seal and bearing failure.
To avoid such a problem, it has been proposed to provide a cooling
system for turbocharges for cooling the turbocharge after the
engine has been shut off. Rust, in U.S. Pat. No. 3,827,236, issued
Aug. 6, 1974, discloses such a system which includes an auxiliary
pump which is controlled by a temperature responsive switch in the
turbocharger. After the engine is shut down, and when temperatures
are sufficiently high as to cause bearing damage, the auxiliary
pump is driven by an electric motor to provide cooling oil until
safe temperatures are attained. While the Rust system also works
well for its intended purpose, it requires additional equipment in
the form of switches, pumps, etc., and also imposes a drain on the
battery when the engine is not running.
SUMMARY OF THE INVENTION
It is the principal object of the invention to provide a new and
improved turbocharger. More specifically, it is an object of the
invention to provide a turbocharger construction wherein means are
provided for cooling the housing in the area near the bearings and
the seal when the engine is shut off, and which are inexpensive in
construction and do not require an operative power source when the
engine is shut down to perform the function.
An exemplary embodiment of the invention achieves the foregoing
object in a turbocharger construction including a housing having
turbine and compressor chambers. A shaft is in the housing and
extends between and into the chambers and bearings and seals are
disposed in the housing adjacent the chambers for journalling and
sealingly engaging the shaft. An impeller is mounted on the shaft
within the compressor chamber and a turbine wheel is mounted on the
shaft within the turbine chamber. Appropriate air and exhaust
inlets and outlets are provided for the chamber. A coolant passage
is disposed in the housing between the turbine chamber and the
adjacent bearings in heat transfer relation to the turbine chamber
and includes an upper outlet which is adapted to be connected to a
heat exchanger or the like which cools engine coolant and a lower
inlet which is adapted to receive the engine coolant.
Other objects and advantages will become apparent from the
following specification taken in connection with the accompanying
drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of an internal combustion engine
system embodying a turbocharger made according to the
invention;
FIG. 2 is an end view of a turbocharger made according to the
invention with parts broken away for clarity; and
FIG. 3 is a sectional view taken approximately along the line 3--3
of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An exemplary embodiment of a turbocharged internal combustion
engine system embodying the invention is illustrated in FIG. 1 in
schematic form in a closed coolant system and is seen to include a
heat exchanger 10. However, as will be seen, the turbocharger of
the present invention may be advantageously employed in vented
coolant systems. Illustratively, the heat exchanger 10 may include
a removable pressure seal can 12 of conventional construction.
Coolant, after being cooled by the heat exchanger 10 in a
conventional fashion is directed by a pump 14 to an engine 16 to
cool the engine. The engine, during operation, directs exhaust to a
turbocharger 18 which typically may be contained in a closed cover
20 utilized for fire insulation and/or noise suppression purposes.
The engine 16 receives compressed air from the turbocharger 18.
Suitable means are provided so that inlet air is directed to the
turbocharger and spent exhaust gases exit therefrom.
A conduit 22 extends from the coolant system of the engine 16 to
the turbocharger in a manner to be described in greater detail
hereinafter, while a conduit 24 extends from the turbocharger 18 to
the heat exchanger 10 or other suitable engine coolant compartment
to redirect coolant at an elevated temperature to the heat
exchanger. In addition, means (not shown) are provided for
directing engine lubricant to and from the turbocharger for the
purpose of lubricating bearings employed in the turbocharger
itself.
Referring now to FIGS. 2 and 3, the turbocharger 18 will be
described in greater detail. The turbocharger 18 includes housings,
generally designated 30, having at opposed ends, a turbine chamber
32 and a compressor chamber 34. The chambers 32 and 34 are
separated by a journalling housing 36. A shaft 38 extends through a
bore 40 in the journalling housing 36. A shaft 38 extends through a
bore 40 in the journalling section 36 and into the chambers 32 and
34. Within the chamber 32, the shaft mounts a bladed turbine wheel
42 of conventional construction, while in the compressor chamber
34, a bladed impeller wheel 44 is similarly carried by the
shaft.
The turbine chamber 32 includes an exhaust gas inlet 46 which may
be connected to the engine 16 in a conventional fashion and through
which exhaust gases will flow to impinge against the turbine wheel
42 and drive the same as well as the shaft 38. Spent exhaust gases
exit the chamber 32 through an outlet 48.
The compressor chamber 34 includes an inlet 50 through which
combustion air may enter the chamber 34 to be compressed by the
impeller 44 when driven by the shaft 38. The chamber 34 includes an
outlet 51 which is connected to the engine in a conventional
fashion to deliver compressed combustion air thereto.
The journalling section 36, at opposite ends thereof, and within
the bore 38, mounts bearings 52 and 53, the bearings 52 being
adjacent the compressor chamber 34 and the bearings 53 being
adjacent the turbine chamber 32. Seals 54 and 55 engage the shaft
38 adjacent the chambers 34 and 32, respectively, preventing the
entry of gas and the exit of lubricant into and from the
journalling section 36. The journalling section 36 includes an oil
inlet 56 into which oil may be introduced from the oil pump of the
engine 16 and an oil outlet 58 from which oil may pass back to the
engine 16. Passages 60 extend from the inlet 56 to the bearings 53
to deliver lubricating oil thereto. Oil emanating from the bearings
53, after lubricating and cooling the same, will impinge upon a
surface 61 adjacent the seal 55 flow to the outlet 58 via a chamber
62 in the journalling section 36. Similar passages 64 direct
lubricating and cooling oil to the bearings 52 and other components
adjacent the compressor chamber 34, generally in the manner
disclosed in the previously identified Miller patent, the details
of which are incorporated by reference.
Interposed between the bearings 53, which are adjacent the turbine
chamber 32, and the turbine chamber 32, and adjacent to the seal 55
and in heat transfer relation with such components is an annular
chamber 66 which surrounds the shaft 38. The chamber 66 includes a
lower inlet 68 which is adapted to be connected to the coolant
system of the engine 16 to receive coolant therefrom. The annular
chamber 66 also includes an upper outlet 70 which is adapted to be
connected to the heat exchanger 10.
As a result of the foregoing, it will be appreciated that engine
coolant will flow through the chamber 66 from the bottom to the top
thereof to the heat exchanger 10 to provide some cooling action for
the bearings 53 during operation of the engine 16. However, during
engine operation, principal cooling of the bearings 53 takes place
by reason of the passage of oil thereto through the passages
60.
However, when the engine is turned off, the oil pump associated
therewith will no longer deliver oil to cool the bearings 53 and
some oil will remain within the bearings 53 or the seal 55 and on
the surface 61 of the chamber 62. Heat from the hot turbine chamber
32 adjacent to the bearings 53, seal 55 and the chamber surface 61
could cause such residual lubricant to coke up if such heat
transfer were not impeded. In the present invention, when employed
in a closed coolant system as illustrated, such heat transfer is
impeded by the provision of the engine coolant in the chamber 66
which will flow therethrough after the engine has been turned off,
due to thermosiphoning. As can be ascertained from FIG. 1 and the
foregoing description of the specifics of the turbocharger
construction, by virtue of the location of the inlet and outlet
cooling passages, hot coolant and steam will rise and be replaced
by fresh coolant from engine system supply. That is, coolant will
thermosiphon through the chamber 66. Ebullient cooling will then
occur in the chamber 66, principally on the wall thereof shared by
the turbine chamber 32 to cool the same. To the extent that any
vapors generated by such ebullient cooling do not condense within
the chamber 66, they will exit through the upper outlet to the heat
exchanger where condensation will occur to continue to the draw of
coolant through the chamber 66. The action will continue until such
time as an equilibrium is attained. At that point, the temperature
of the turbine chamber 32 will be considerably reduced from its
operating temperature to a low level whereat coking of lubricant at
the bearings 53, seal 55 and surface 61 will not occur. Thus, long
life of such bearings and seals is assured.
The invention may also be utilized in vented coolant systems so
long as the outlet 70 of the chamber 66 is at or below the upper
surface of the coolant employed to insure that the chamber will
always be filled with coolant. In such a system, thermosiphoning
will not occur but ebullient cooling will, rapidly lowering the
temperature of the turbocharger in the vicinity of the bearings 53,
the seal 55 and the surface 61 to the boiling point of the coolant
to prevent coking of the lubricant.
In general, it is not necessary to provide similar means for
cooling the bearings 52 in that, being adjacent the air inlet 50,
incoming air will be sufficiently cool so as to maintain those
bearings at a low level temperature when the engine is shut
off.
While the invention has been described and illustrated with the
turbocharger in series with the engine and the heat exchanger,
other coolant routes may be employed. For example, coolant from the
outlet 70 could be returned to the engine above the level of the
outlet 70. Alternatively, the coolant route shown in FIG. 1 could
be in parallel with an additional coolant route directly from the
engine to the heat exchanger.
From the foregoing, it will be apparent that a turbocharger made
according to the invention ensures adequate cooling of bearings
even after the engine is turned off in a relatively severe
operating environment, such as a closed housing. It will also be
appreciated that auxiliary equipment, such as an auxiliary pump,
control switches, and an auxiliary power source other than the
engine are not required. As a consequence, an internal combustion
engine system embodying a turbocharger made according to the
invention can be fabricated with a minimum of expense and yet will
have long life.
* * * * *