U.S. patent application number 17/048028 was filed with the patent office on 2021-06-10 for blowby-gas reflux system, blowby-gas reflux-system control device, and recording medium.
The applicant listed for this patent is ISUZU MOTORS LIMITED. Invention is credited to Hideki OSADA.
Application Number | 20210172353 17/048028 |
Document ID | / |
Family ID | 1000005431619 |
Filed Date | 2021-06-10 |
United States Patent
Application |
20210172353 |
Kind Code |
A1 |
OSADA; Hideki |
June 10, 2021 |
BLOWBY-GAS REFLUX SYSTEM, BLOWBY-GAS REFLUX-SYSTEM CONTROL DEVICE,
AND RECORDING MEDIUM
Abstract
A blowby-gas reflux system 60 has: a blowby-gas reflux path 70;
an atmospheric release mechanism 90 that releases, into the
atmosphere, blowby gas Gb that has passed through an oil separator
80; and a control device 50. The control device 50 is provided
with: a determination unit 51 that determines whether oil caulking
occurs in a compressor 41 on the basis of the operating state of
the compressor; and a control unit 51 that stops the release of the
blowby gas into the atmosphere performed by the atmospheric release
mechanism if the determination unit determines that oil caulking
does not occur, and that causes the atmospheric release mechanism
to release the blowby gas into the atmosphere if the determination
unit determines that oil caulking occurs.
Inventors: |
OSADA; Hideki;
(Fujisawa-shi, Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ISUZU MOTORS LIMITED |
Tokyo |
|
JP |
|
|
Family ID: |
1000005431619 |
Appl. No.: |
17/048028 |
Filed: |
April 12, 2019 |
PCT Filed: |
April 12, 2019 |
PCT NO: |
PCT/JP2019/015898 |
371 Date: |
October 15, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01M 13/04 20130101;
F01M 2250/00 20130101; F01M 2013/0044 20130101; F01M 2013/027
20130101 |
International
Class: |
F01M 13/04 20060101
F01M013/04 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 16, 2018 |
JP |
2018-078205 |
Claims
1. A blow-by gas reflux system comprising: a blow-by gas reflux
path causing a blow-by gas discharged from an internal combustion
engine to pass through an oil separator, which is configured to
remove oil from the blow-by gas, and then refluxing the blow-by gas
to an intake passage of the internal combustion engine positioned
on a further upstream-side than a compressor of a supercharger
disposed on the intake passage; an atmospheric release mechanism
disposed at a position further downstream side of the blow-by gas
reflux path than the oil separator, the atmospheric release
mechanism being configured to release the blow-by gas after passing
through the oil separator into an atmosphere; and a control device;
configured to: determine whether oil caulking occurs in the
compressor, based on an operating state of the compressor, the oil
caulking being caused due to oil contained in the blow-by gas after
passing through die oil separator; in a case it is determined that
the oil caulking does not occur, stop the release of the blow-by
gas into the atmosphere performed by die atmospheric release
mechanism; and in a case it is determined that the oil caulking
occurs, control the atmospheric release mechanism to release the
blow-by gas into the atmosphere.
2. The blow-by gas reflux system according to claim 1, wherein the
control device is configured to further determine whether an
atmospheric temperature is equal to or lower than a predetermined
threshold value, wherein in a case it is determined that the oil
caulking occurs and also determined that the atmospheric
temperature is equal to or lower than the threshold value, the
control device is configured to stop the release of the blow-by gas
into the atmosphere performed by the atmospheric release mechanism,
and wherein in a case it is determined that the oil caulking occurs
and also determined that the atmospheric temperature is not equal
to or lower titan the threshold value, the control device is
configured to control the atmospheric release mechanism to release
the blow-by gas into the atmosphere.
3. A control device applied to a blow-by gas reflux system, the
blow-by gas reflux system comprising: a blow-by gas reflux path for
causing a blow-by gas discharged from an internal combustion engine
to pass through an oil separator, which is configured to remove oil
from the blow-by gas, and then refluxing the blow-by gas to an
intake passage of the internal combustion engine positioned on a
further upstream-side than a compressor of a supercharger disposed
on the intake passage; and an atmospheric release mechanism
disposed at a further downstream-side part of the blow-by gas
reflux path than the oil separator and configured to release the
blow-by gas after passing through the oil separator into an
atmosphere, the control device being configured to: determine
whether oil caulking occurs in the compressor, based on an
operating state of the compressor, the oil caulking being caused
due to oil contained in the blow-by gas after passing through the
oil separator; in a case it is determined that the oil caulking
does not occur, stop the release of the blow-by gas into the
atmosphere performed by the atmospheric release mechanism; and in a
case it is determined that the oil caulking occurs, control the
atmospheric release mechanism to release the blow-by gas into the
atmosphere.
4. A non-transitory computer-readable storage medium storing a
computer program readable by a computer of a vehicle, the vehicle
comprising a blow-by gas reflux system comprising: a blow-by gas
reflux path for causing a blow-by gas discharged from an internal
combustion engine to pass through an oil separator configured to
remove oil from the blow-by gas and then refluxing the blow-by gas
to an intake passage of the internal combustion engine positioned
on a further upstream-side than a compressor of a supercharger
disposed on the intake passage; and an atmospheric release
mechanism disposed at a further downstream-side part of the blow-by
gas reflux path than the oil separator and configured to release
the blow-by gas after passing through the oil separator into an
atmosphere, the computer program, when executed by the computer,
causes the vehicle to perform: determining whether oil caulking
occurs in the compressor, based on an operating state of the
compressor, the oil caulking being caused due to oil contained in
the blow-by gas after passing through the oil separator; in a case
it is determined that the oil caulking does not occur, stopping the
release of the blow-by gas into the atmosphere performed by the
atmospheric release mechanism; and in a case it is determined that
the oil caulking occurs, causing the atmospheric release mechanism
to release the blow-by gas into the atmosphere.
5. The non-transitory computer-readable storage medium according to
claim 4, wherein the computer program, when executed by the
computer, causes the vehicle to further execute: determining
whether an atmospheric temperature is equal to or lower than a
predetermined threshold value, when it is determined that the oil
caulking occurs; in a case it is determined that the oil caulking
occurs and it is also determined that the atmospheric temperature
is equal to or lower than the threshold value, stopping the release
of the blow-by gas into the atmosphere performed by the atmospheric
release mechanism; and in a case it is determined that the oil
caulking occurs and it is also determined that the atmospheric
temperature is not equal to or lower than the threshold value,
causing the atmospheric release mechanism to release the blow-by
gas into the atmosphere.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a blow-by gas reflux
system, a blow-by gas reflux system control device and a storage
medium.
BACKGROUND ART
[0002] In the related art, known is a blow-by gas reflux system
including a blow-by gas reflux path for refluxing a blow-by gas
discharged from an internal combustion engine to an intake passage
on a further upstream-side than a compressor of a supercharger
after causing the blow-by gas to pass through an oil separator
configured to remove oil from the blow-by gas (for example, refer
to PTL 1). According to the blow-by gas reflux system, it is
possible to suppress oil contained in the blow-by gas discharged
from the internal combustion engine from being released into the
atmosphere in a large amount.
[0003] In the meantime, PTL 2 can be exemplified as another patent
literature. PTL 2 discloses a phenomenon where oil contained in the
blow-by gas caulks (carbonization) (referred to as "oil
caulking").
CITATION LIST
Patent Literature
[0004] PTL 1: JP-A-2011-33032
[0005] PTL 2: JP-A-2005-264759
SUMMARY OF INVENTION
Technical Problem
[0006] In the blow-by gas reflux system, the oil contained in the
blow-by gas discharged from the internal combustion engine is
removed via the oil separator. However, the oil may not be
completely removed by the oil separator, so that a small amount of
oil may be contained in the blow-by gas after passing through the
oil separator. In a case where an operating state of the compressor
is a high supercharging operating state (a case where an intake air
temperature after supercharging is high, a case where an intake air
pressure after supercharging is high, and the like), when the
blow-by gas after passing through the oil separator is refluxed to
the intake passage and is introduced into the compressor, oil
caulking due to the oil contained in the blow-by gas may occur in
the compressor.
[0007] The present disclosure has been made in view of the above
situations, and an object thereof is to provide a blow-by gas
reflux system, a blow-by gas reflux system control device and a
storage medium capable of suppressing occurrence of oil
caulking.
Solution to Problem
[0008] In order to achieve the above object, a blow-by gas reflux
system according to an illustrative aspect of the present
disclosure includes: a blow-by gas reflux path causing a blow-by
gas discharged from an internal combustion engine to pass through
an oil separator, which is configured to remove oil from the
blow-by gas, and then refluxing the blow-by gas to an intake
passage of the internal combustion engine positioned on a further
upstream-side than a compressor of a supercharger disposed on the
intake passage; an atmospheric release mechanism disposed at a
position further downstream side of the blow-by gas reflux path
than the oil separator, the atmospheric release mechanism being
configured to release the blow-by gas after passing through the oil
separator into an atmosphere; and a control device, wherein the
control device includes: a determination unit configured to
determine whether oil caulking occurs in the compressor, based on
an operating state of the compressor, the oil caulking being caused
due to oil contained in the blow-by gas after passing through the
oil separator; and a control unit configured to: in a case the
determination unit determines that the oil caulking does not occur,
stop the release of the blow-by gas into the atmosphere performed
by the atmospheric release mechanism; and in a case the
determination unit determines that the oil caulking occurs, control
the atmospheric release mechanism to release the blow-by gas into
the atmosphere.
[0009] Further, in order to achieve the above object, a control
device of a blow-by gas reflux system of an illustrative aspect of
the present disclosure is a control device applied to a blow-by gas
reflux system, the blow-by gas reflux system including: a blow-by
gas reflux path for causing a blow-by gas discharged from an
internal combustion engine to pass through an oil separator, which
is configured to remove oil from the blow-by gas, and then
refluxing the blow-by gas to an intake passage of the internal
combustion engine positioned on a further upstream-side than a
compressor of a supercharger disposed on the intake passage; and an
atmospheric release mechanism disposed at a further downstream-side
part of the blow-by gas reflux path than the oil separator and
configured to release the blow-by gas after passing through the oil
separator into an atmosphere, the control device includes: a
determination unit configured to determine whether oil caulking
occurs in the compressor, based on an operating state of the
compressor, the oil caulking being caused due to oil contained in
the blow-by gas after passing through the oil separator; and a
control unit configured to: in a case the determination unit
determines that the oil caulking does not occur, stop the release
of the blow-by gas into the atmosphere performed by the atmospheric
release mechanism; and in a case the determination unit determines
that the oil caulking occurs, control the atmospheric release
mechanism to release the blow-by gas into the atmosphere.
[0010] Further, a computer-readable storage medium of an
illustrative aspect of the present disclosure is a
computer-readable medium storing a computer program readable by a
computer of a vehicle, the vehicle including a blow-by gas reflux
system including a blow-by gas reflux path for causing a blow-by
gas discharged from an internal combustion engine to pass through
an oil separator configured to remove oil from the blow-by gas and
then refluxing the blow-by gas to an intake passage of the internal
combustion engine positioned on a further upstream-side than a
compressor of a supercharger disposed on the intake passage; and an
atmospheric release mechanism disposed at a further downstream-side
part of the blow-by gas reflux path than the oil separator and
configured to release the blow-by gas after passing through the oil
separator into an atmosphere, and wherein the computer program,
when executed by the computer, causes the vehicle to perform:
determining whether oil caulking occurs in the compressor, based on
an operating state of the compressor, the oil caulking being caused
due to oil contained in the blow-by gas after passing through the
oil separator; stopping the release of the blow-by gas into the
atmosphere performed by the atmospheric release mechanism, when it
is determined that the oil caulking does not occur; and causing the
atmospheric release mechanism to release the blow-by gas into the
atmosphere, when it is determined that the oil caulking occurs.
Advantageous Effects of Invention
[0011] According to the present disclosure, it is possible to
suppress occurrence of oil caulking.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a pictorial configuration view of an internal
combustion engine system to which a blow-by gas reflux system in
accordance with a first embodiment and a second embodiment is
applied, depicting a state where a blow-by gas is refluxed to an
intake passage.
[0013] FIG. 2 is a pictorial configuration view of the internal
combustion engine system to which the blow-by gas reflux system in
accordance with the first embodiment and the second embodiment is
applied, depicting a state where the blow-by gas is released into
an atmosphere.
[0014] FIG. 3 is a flowchart depicting an example of control
processing of an atmospheric release mechanism that is performed by
a control device in accordance with the first embodiment.
[0015] FIG. 4 is a flowchart depicting an example of control
processing of the atmospheric release mechanism that is performed
by the control device in accordance with the second embodiment.
DESCRIPTION OF EMBODIMENTS
First Embodiment
[0016] Hereinbelow, a blow-by gas reflux system 60 and a control
device 50 of the blow-by gas reflux system 60 in accordance with a
first embodiment will be described with reference to the drawings.
Specifically, a schematic configuration of an internal combustion
engine system 1 to which the blow-by gas reflux system 60 in
accordance with the present embodiment is applied is first
described, and the blow-by gas reflux system 60 and the control
device 50 thereof are then described.
[0017] The internal combustion engine system 1 exemplified in FIG.
1 includes an internal combustion engine 10, an intake passage 20,
an air cleaner 30, a supercharger 40, a control device 50, and a
blow-by gas reflux system 60. In the meantime, the internal
combustion engine system 1 in accordance with the present
embodiment is mounted on a vehicle. A specific type of the vehicle
is not particularly limited, and a variety of vehicles such as a
passenger car, a commercial vehicle can be used.
[0018] The internal combustion engine 10 has an internal combustion
engine main body 11. The internal combustion engine main body 11
has a cylinder block in which cylinders are formed, a cylinder head
disposed on an upper part of the cylinder block, a piston disposed
in the cylinder, and a crankshaft connected to the piston via a
connecting rod. Also, the internal combustion engine 10 has a
crankcase 12. The crankcase 12 is connected to a lower part of the
cylinder block. The crankshaft is accommodated in the crankcase 12.
Also, the internal combustion engine 10 has a cylinder head cover
13. The cylinder head cover 13 is disposed on an upper part of the
cylinder head. In the cylinder head cover 13, a valve mechanism
such as a cam is accommodated.
[0019] A specific type of the internal combustion engine 10 is not
particularly limited, and a variety of internal combustion engines
such as a Diesel engine, a gasoline engine and the like can be
used. In the present embodiment, a Diesel engine is used as an
example of the internal combustion engine 10.
[0020] The intake passage 20 is a passage through which an intake
air (A) sucked in the internal combustion engine 10 passes. A
downstream-side end portion of the intake passage 20 connects to an
intake port of the internal combustion engine 10. In the meantime,
although not shown, the internal combustion engine 10 has also an
exhaust passage through which an exhaust air discharged from the
internal combustion engine 10 passes. An upstream-side end portion
of the exhaust passage connects to an exhaust port of the internal
combustion engine 10. The air cleaner 30 is disposed at a further
upstream part of the intake passage 20 than the supercharger 40. In
the meantime, the intake air that flows into the intake passage 20
from an upstream-side end portion of the intake passage 20 is fresh
air. The air cleaner 30 is a member having a function of removing
foreign materials such as dirt and dust contained in the fresh
air.
[0021] The supercharger 40 is a device configured to supercharge
the intake air sucked in the internal combustion engine 10 by a
compressor 41. A specific configuration of the supercharger 40 is
not particularly limited inasmuch as it has such function. For
example, a variety of superchargers such as a turbo supercharger
where the compressor 41 is driven using energy of the exhaust air,
a mechanical supercharger where the compressor 41 is driven by
power of the internal combustion engine 10, an electric
supercharger where the compressor 41 is driven by power of an
electric motor, and the like can be used. In the present
embodiment, a turbo supercharger is used as an example of the
supercharger 40. Specifically, the supercharger 40 in accordance
with the present embodiment includes a turbine (not shown) disposed
on the exhaust passage, the compressor 41 disposed on the intake
passage 20, and a rotary shaft (not shown) coupling the turbine and
the compressor 41. The turbine is driven by receiving the energy of
the exhaust air, so that the compressor 41 connected to the turbine
via the rotary shaft is driven to supercharge the intake air.
[0022] The control device 50 is configured by an electronic control
device. Specifically, the control device 50 in accordance with the
present embodiment includes a microcomputer having a CPU (Central
Processing Unit) 51 configured to execute a variety of control
processing and a storage unit 52 configured to store a program,
data and the like that are used for operations of the CPU 51. In
the meantime, the storage unit 52 includes a ROM (Read Only
Memory), a RAM (Random Access Memory), and the like.
[0023] The control device 50 in accordance with the present
embodiment is configured to control operations of the internal
combustion engine 10 by controlling a fuel injection timing, a fuel
injection amount and the like of the internal combustion engine 10.
Also, the control device 50 in accordance with the present
embodiment functions as a control device of the blow-by gas reflux
system 60. In the meantime, the control device of the blow-by gas
reflux system 60 may also be a control device that is provided
separately from the control device configured to control the
internal combustion engine 10.
[0024] The blow-by gas reflux system 60 in accordance with the
present embodiment is applied to the internal combustion engine
system 1 as described above. Subsequently, a configuration of the
blow-by gas reflux system 60 is described. The blow-by gas reflux
system 60 includes a blow-by gas reflux path 70, an oil separator
80, an atmospheric release mechanism 90 (an atmospheric release
passage 91 and a three-way valve 92), a sensor 100a, a sensor 100b
and the control device 50 as a part of the constitutional
elements.
[0025] The blow-by gas reflux path 70 is a flow path for refluxing
a blow-by gas (Gb) discharged from the internal combustion engine
10 to a further upstream-side part (in the present embodiment, a
further downstream-side part than the air cleaner 30) of the intake
passage 20 than the compressor 41 after causing the blow-by gas to
pass through the oil separator 80. Specifically, the blow-by gas
reflux path 70 in accordance with the present embodiment has an
upstream-side end portion connected to a blow-by gas exhaust port
provided on an outer wall of a side surface of the cylinder head
cover 13 of the internal combustion engine 10, and a
downstream-side end portion connected to a part of the intake
passage 20 on a further upstream-side than the compressor 41 and on
a further downstream-side than the air cleaner 30. The oil
separator 80 is disposed on the way of the blow-by gas reflux path
70.
[0026] The oil separator 80 has a function of removing oil
contained in the blow-by gas introduced into the oil separator 80.
A specific configuration of the oil separator 80 is not
particularly limited inasmuch as it has such function, and a
well-known oil separator (which may also be referred to as an oil
mist separator) can be used. For this reason, the descriptions of
the detailed structure of the oil separator 80 are omitted.
[0027] The blow-by gas generated in the internal combustion engine
10 is leaked from a gap between each cylinder and the piston
therein to the crankcase 12, passes through the inside of the
cylinder head cover 13, and is then introduced into the blow-by gas
reflux path 70. Then, the blow-by gas passes through the oil
separator 80 and is then refluxed to a further upstream-side part
of the intake passage 20 than the compressor 41. In the meantime,
the oil contained in the blow-by gas discharged from the internal
combustion engine 10 is removed as it passes through the oil
separator 80. However, the oil may not be completely removed by the
oil separator 80. In this case, a small amount of oil may be
contained in the blow-by gas after passing through the oil
separator 80.
[0028] The atmospheric release mechanism 90 is disposed at a
further downstream-side part of the blow-by gas reflux path 70 than
the oil separator 80. The atmospheric release mechanism 90 is
configured to release the blow-by gas after passing through the oil
separator 80 into the atmosphere, in response to an instruction of
the control device 50. A specific configuration of the atmospheric
release mechanism 90 is not particularly limited inasmuch as it has
such function. However, the atmospheric release mechanism 90 in
accordance with the present embodiment has an atmospheric release
passage 91 and a three-way valve 92, as an example.
[0029] The atmospheric release passage 91 has a downstream-side end
portion opening to the atmosphere and an upstream-side end portion
connected to a further downstream-side passage part of the blow-by
gas reflux path 70 than the oil separator 80. The three-way valve
92 is disposed at the connection place of the atmospheric release
passage 91 to the blow-by gas reflux path 70. That is, the
atmospheric release passage 91 in accordance with the present
embodiment is connected to the blow-by gas reflux path 70 via the
three-way valve 92.
[0030] The three-way valve 92 has a gas inlet 93, a gas outlet 94a
and a gas outlet 94b, and the gas inlet 93 and the gas outlet 94a
are provided at a further downstream-side passage part of the
blow-by gas reflux path 70 than the oil separator 80. The
upstream-side end portion of the atmospheric release passage 91 is
connected to the gas outlet 94b of the three-way valve 92. The gas
inlet 93 of the three-way valve 92 is always in an opened state. In
the meantime, the three-way valve 92 has such a structure that it
is controlled by the control device 50, thereby opening and closing
independently each of the gas outlet 94a and the gas outlet
94b.
[0031] As exemplified in FIG. 1, when the three-way valve 92 opens
the gas outlet 94a and closes the gas outlet 94b, the blow-by gas
after passing through the oil separator 80 is not released into the
atmosphere and passes through the blow-by gas reflux path 70 and is
then refluxed to the intake passage 20.
[0032] In the meantime, as exemplified in FIG. 2, when the
three-way valve 92 closes the gas outlet 94a and opens the gas
outlet 94b, the blow-by gas after passing through the oil separator
80 is released into the atmosphere through the atmospheric release
passage 91 (in this case, the blow-by gas is not refluxed to the
intake passage 20). In this way, the atmospheric release mechanism
90 in accordance with the present embodiment releases the blow-by
gas after passing through the oil separator 80 into the
atmosphere.
[0033] The three-way valve 92 is an example of a member having a
function as a flow path switching mechanism configured to switch a
flow destination of the blow-by gas after passing through the oil
separator 80 between the atmospheric release passage 91 and the
intake passage 20.
[0034] The configuration of the flow path switching mechanism is
not limited to the three-way valve 92 as described above. As
another example of the flow path switching mechanism, the flow path
switching mechanism may include a first opening/closing valve
disposed on the atmospheric release passage 91 and configured to
open/close the atmospheric release passage 91 and a second
opening/closing valve disposed on a further downstream-side passage
part of the blow-by gas reflux path 70 than the connection place of
the atmospheric release passage 91 and configured to open/close the
connection place. In this case, the control device 50 can release
the blow-by gas after passing through the oil separator 80 into the
atmosphere through the atmospheric release passage 91 by
controlling the first opening/closing valve to an opened state and
the second opening/closing valve to a closed state. On the other
hand, the control device 50 can reflux the blow-by gas after
passing through the oil separator 80 to the intake passage 20 by
controlling the first opening/closing valve to a closed state and
the second opening/closing valve to an opened state.
[0035] Also, the place of the blow-by gas reflux path 70 on which
the three-way valve 92 is disposed may be a further downstream-side
part than the oil separator 80 and is not limited to the place
exemplified in FIGS. 1 and 2. In the meantime, as the place of the
blow-by gas reflux path 70 on which the three-way valve 92 is
disposed is closer to the oil separator 80, it is possible to more
effectively suppress the blow-by gas from being cooled by the
atmosphere until the blow-by gas after passing through the oil
separator 80 flows into the three-way valve 92. Therefore, it is
preferably to set the disposal place of the three-way valve 92,
taking into account this point.
[0036] Referring to FIG. 1, the sensor 100a is configured to detect
a temperature (referred to as "intake air temperature T after
supercharging") of the intake air supercharged by the compressor 41
and to transmit a detection result to the control device 50. That
is, the sensor 100a in accordance with the present embodiment is a
temperature sensor configured to detect the intake air temperature
T after supercharging. Specifically, the sensor 100a in accordance
with the present embodiment is disposed near an intake air outlet
of the compressor 41, and is configured to detect a temperature of
the intake air immediately after discharged from the compressor
41.
[0037] The sensor 100b is configured to detect a temperature of the
atmosphere (referred to as "atmospheric temperature Ta") and to
transmit a detection result to the control device 50. That is, the
sensor 100b in accordance with the present embodiment is a
temperature sensor configured to detect the atmospheric temperature
Ta. In the meantime, the detection result of the sensor 100b is not
used in control processing (control processing shown in FIG. 3,
which will be described later) in accordance with the present
embodiment, and the detection result of the sensor 100b is used in
control processing of FIG. 4 (control processing of a second
embodiment). For this reason, the blow-by gas reflux system 60 in
accordance with the present embodiment may also be configured not
to include the sensor 100b.
[0038] Subsequently, control of the atmospheric release mechanism
90 that is performed by the control device 50 is described with
reference to a flowchart shown in FIG. 3. In the meantime, each
step in FIG. 3 is executed by the CPU 51 of the control device 50,
based on a program stored in the storage unit 52. The control
device 50 first starts the flowchart of FIG. 3 at the same time
when the internal combustion engine 10 starts (i.e., the flowchart
of FIG. 3 is periodically executed during the operation of the
internal combustion engine 10). Also, it is assumed that upon first
start of FIG. 3, the release of the blow-by gas into the atmosphere
performed by the atmospheric release mechanism 90 is stopped.
[0039] In step S10 of FIG. 3, the control device 50 determines
whether oil caulking due to the oil contained in the blow-by gas
(Gb) after passing through the oil separator 80 occurs in the
compressor 41, based on the operating state of the compressor 41.
The specific execution content of step S10 is described as
follows.
[0040] First, the control device 50 in accordance with the present
embodiment uses the temperature (i.e., the intake air temperature T
after supercharging) of the intake air supercharged by the
compressor 41, as a parameter relating to the operating state of
the compressor 41. As an operating load of the compressor 41
increases, the intake air temperature T after supercharging intends
to increase. That is, the intake air temperature T after
supercharging is a parameter having correlation with the operating
load of the compressor 41. The control device 50 obtains the
detection result of the sensor 100a to obtain the intake air
temperature T after supercharging. The control device 50 determines
whether the obtained intake air temperature T after supercharging
is equal to or higher than a predetermined threshold value T1, and
determines that oil caulking occurs (YES) when it is determined
that the intake air temperature T after supercharging is equal to
or higher than the threshold value T1.
[0041] The threshold value T1 may be any value by which it is
possible to determine that oil caulking occurs when the intake air
temperature T after supercharging is equal to or higher than the
corresponding value. As the threshold value T1, an appropriate
value may be obtained in advance by performing a test, a simulation
and the like, and may be stored in the storage unit 52 of the
control device 50. In this way, step S10 in accordance with the
present embodiment is executed.
[0042] The execution content of step S10 is not limited to the
above. As another example, in step S10, the control device 50 may
estimate the intake air temperature T after supercharging, based on
a parameter (for example, the operating state of the internal
combustion engine 10) having correlation with the intake air
temperature T after supercharging, instead of using the detection
result of the sensor 100a. Specifically, in this case, a control
map in which the intake air temperature T after supercharging is
associated with the number of rotations of the internal combustion
engine 10 and the load of the internal combustion engine 10 (for
example, a fuel injection amount) is stored in advance in the
storage unit 52. The control device 50 may obtain the number of
rotations and the load of the internal combustion engine 10,
extract the intake air temperature T after supercharging
corresponding to the obtained number of rotations and load from the
control map, and use the extracted intake air temperature T after
supercharging in step S10.
[0043] Alternatively, in step S10, the control device 50 may use a
pressure (referred to as "supercharging pressure P") of the intake
air supercharged by the compressor 41, as a parameter relating to
the operating state of the compressor 41. The supercharging
pressure P is also a parameter whose value tends to increase as the
operating load of the compressor 41 increases. In the meantime,
when the supercharging pressure P is used as a parameter relating
to the operating state of the compressor 41, a pressure sensor
configured to detect the supercharging pressure P is used as the
sensor 100a. In step S10, the control device 50 determines whether
the supercharging pressure P detected by the sensor 100a as the
pressure sensor is equal to or higher than a predetermined
threshold value P1, and determines that oil caulking occurs (YES)
when it is determined that the supercharging pressure P is equal to
or higher than the threshold value P1. Similarly to the threshold
value T1, the threshold value P1 may also be any value by which it
is possible to determine that oil caulking occurs when the
supercharging pressure P is equal to or higher than the
corresponding value. As the threshold value P1, an appropriate
value may be obtained in advance by performing a test, a simulation
and the like, and may be stored in the storage unit 52 of the
control device 50.
[0044] Also, when obtaining the supercharging pressure P, the
control device 50 may estimate the same, based on a parameter (for
example, the operating state of the internal combustion engine 10)
having correlation with the supercharging pressure P. Specifically,
in this case, a control map in which the supercharging pressure P
is associated with the number of rotations of the internal
combustion engine 10 and the load of the internal combustion engine
10 is stored in advance in the storage unit 52. The control device
50 may obtain the number of rotations and the load of the internal
combustion engine 10, extract the supercharging pressure P
corresponding to the obtained number of rotations and load from the
control map, and use the extracted supercharging pressure P in step
S10.
[0045] By the diverse methods, step S10 can be executed. When a
determination result in step S10 is NO (when it is determined that
oil caulking does not occur), the control device 50 executes step
S20. In step S20, the control device 50 stops the release of the
blow-by gas into the atmosphere performed by the atmospheric
release mechanism 90 (when the release of the blow-by gas into the
atmosphere has been already stopped before execution of step S20,
this state is maintained in step S20). Specifically, as described
above, the control device 50 controls the gas outlet 94a of the
three-way valve 92 of the atmospheric release mechanism 90 to the
opened state and the gas outlet 94b to the closed state. Thereby,
the blow-by gas after passing through the oil separator 80 passes
through the blow-by gas reflux path 70 and is then refluxed to the
intake passage 20. After executing step S20, the control device 50
again executes the flowchart from the start (return).
[0046] On the other hand, when a determination result in step S10
is YES (when it is determined that oil caulking occurs), the
control device 50 executes step S30. In step S30, the control
device 50 causes the atmospheric release mechanism 90 to release
the blow-by gas into the atmosphere. Specifically, as described
above, the control device 50 controls the gas outlet 94a of the
three-way valve 92 of the atmospheric release mechanism 90 to the
closed state and the gas outlet 94b to the opened state. Thereby,
the blow-by gas after passing through the oil separator 80 passes
through the atmospheric release passage 91 and is then released to
the atmosphere.
[0047] After executing step S30, the control device 50 again
executes the flowchart from the start (return). In the meantime,
the release of the blow-by gas into the atmosphere in step S30 is
continuously executed until when a determination result in step S10
becomes NO during the re-execution of the flowchart. That is,
according to the present embodiment, the release of the blow-by gas
into the atmosphere performed by the atmospheric release mechanism
90 is continuously executed until it is determined that oil
caulking does not occur in the compressor 41.
[0048] In the present embodiment, the CPU 51 of the control device
50 that executes step S10 is an example of a member having a
function as "determination unit". Also, the CPU 51 of the control
device 50 that executes step S20 and step S30 is an example of a
member having a function as "control unit".
[0049] According to the present embodiment as described above, when
it is determined based on the operating state of the compressor 41
that oil caulking occurs (YES in step S10), the control processing
relating to step S30 is executed, so that the blow-by gas after
passing through the oil separator 80 can be released into the
atmosphere. Thereby, since the blow-by gas containing oil is not
introduced into the compressor 41, it is possible to suppress oil
caulking from occurring in the compressor 41. Also, according to
the present embodiment, since the blow-by gas after passing through
the oil separator 80 is released into the atmosphere, the amount of
oil in the blow-by gas that is released into the atmosphere is
smaller, as compared to a case where the blow-by gas before passing
through the oil separator 80 is released into the atmosphere. That
is, according to the present embodiment, while suppressing the oil
contained in the blow-by gas discharged from the internal
combustion engine 10 from being released into the atmosphere in a
large amount, it is possible to suppress oil caulking from
occurring in the compressor 41.
[0050] As a result, according to the present embodiment, while
suppressing atmospheric pollution due to the oil released into the
atmosphere as much as possible, it is possible to suppress oil
caulking from occurring in the compressor 41, thereby suppressing
lowering in supercharging efficiency of the compressor 41 due to
oil caulking.
Second Embodiment
[0051] Subsequently, a blow-by gas reflux system 60 and a control
device 50 in accordance with a second embodiment are described. In
the meantime, the hardware configuration of the blow-by gas reflux
system 60 in accordance with the present embodiment is the same as
that of the blow-by gas reflux system 60 in accordance with the
first embodiment. The processing that is executed by the control
device 50 of the blow-by gas reflux system 60 in accordance with
the present embodiment is different from the first embodiment.
Specifically, the control device 50 in accordance with the present
embodiment is different from the control device 50 in accordance
with the first embodiment, in that a flowchart of FIG. 4 is
executed instead of the flowchart of FIG. 3.
[0052] The flowchart of FIG. 4 is different from the flowchart of
FIG. 3, in that it further includes step S15. The control device 50
in accordance with the present embodiment executes step S15 when a
determination result in step S10 of FIG. 4 is YES. In step S15, the
control device 50 determines whether the atmospheric temperature Ta
is equal to or lower than a predetermined threshold value Ta1
(i.e., low temperature). The technical background of executing step
S15 and detailed contents of step S15 are described as follows.
[0053] First, when step S30 is executed and the blow-by gas after
passing through the oil separator 80 is thus released into the
atmosphere, the blow-by gas does not pass through the connection
place (specifically, the place in which the three-way valve 92 is
disposed) of the atmospheric release mechanism 90 on the blow-by
gas reflux path 70. As a result, a further downstream-side part of
the blow-by gas reflux path 70 than the atmospheric release
mechanism 90 is cooled by the atmosphere, so that the temperature
thereof is lowered.
[0054] Herein, when the atmospheric temperature is low, as the
moisture attached to the further downstream-side part of the
blow-by gas reflux path 70 than the atmospheric release mechanism
90 is frozen, the blow-by gas reflux path 70 is further cooled. In
the cooled state, when the reflux of the blow-by gas to the intake
passage 20 is resumed, the moisture contained in the blow-by gas is
frozen at the time when the moisture is attached to a pipe wall
part of the blow-by gas reflux path 70. As a result, a frozen
material (for example, chips of ice) due to the freezing is
generated in the blow-by gas reflux path 70. When the frozen
material flows downstream together with the blow-by gas and is
introduced into the compressor 41, the compressor 41 may
malfunction.
[0055] Therefore, in the present embodiment, in order to solve the
above problem, step S15 is executed. Specifically, the threshold
value Ta1 that is used for the determination processing in step S15
is stored in advance (i.e., predetermined) in the storage unit 52
of the control device 50 in accordance with the present embodiment.
In the present embodiment, as the threshold value Ta1, an
atmospheric temperature at which the freezing occurs in the further
downstream-side part of the blow-by gas reflux path 70 than the
atmospheric release mechanism 90 is used. That is, in the present
embodiment, when the atmospheric temperature Ta is equal to or
lower than the threshold value Ta1, as the freezing occurs in the
further downstream-side part of the blow-by gas reflux path 70 than
the atmospheric release mechanism 90, the atmospheric temperature
Ta is lowered. As the threshold value Ta1, an appropriate value may
be obtained in advance by performing a test, a simulation and the
like, and may be stored in the storage unit 52 of the control
device 50.
[0056] Then, in step S15, the control device 50 obtains the
atmospheric temperature Ta, based on the detection result of the
sensor 100b, and determines whether the obtained atmospheric
temperature Ta is equal to or lower than the threshold value Ta1
stored in the storage unit 52. When it is determined that the
atmospheric temperature Ta is equal to or lower than the threshold
value Ta1, the control device 50 determines YES and executes step
S20. When it is determined that the atmospheric temperature Ta is
not equal to or lower than the threshold value Ta1, the control
device 50 determines NO and executes step S30.
[0057] That is, when it is determined that oil caulking occurs (YES
in step S10) and it is also determined that the atmospheric
temperature Ta is equal to or lower than the threshold value Ta1
(YES in step S15), the control device 50 in accordance with the
present embodiment stops the release of the blow-by gas into the
atmosphere performed by the atmospheric release mechanism 90 and
refluxes the blow-by gas to the intake passage 20 (step S20), and
when it is determined that oil caulking occurs (YES in step S10)
and it is also determined that the atmospheric temperature Ta is
not equal to or lower than the threshold value Ta1 (NO in step
S15), the control device 50 causes the atmospheric release
mechanism 90 to release the blow-by gas into the atmosphere (step
S30).
[0058] In the present embodiment, the execution sequence of step
S10 and step S15 is not limited to the sequence shown in FIG. 4. As
another example, the control device 50 may execute step S15 before
step S10. In this case, when a determination result in step S15 is
NO, step S10 is executed, and when a determination result in step
S15 is YES, step S20 is executed.
[0059] In the present embodiment, the CPU 51 of the control device
50 that executes step S10 and step S15 is an example of a member
having a function as "determination unit". Also, the CPU 51 of the
control device 50 that executes step S20 and step S30 is an example
of a member having a function as "control unit".
[0060] According to the present embodiment as described above, it
is possible to achieve following effects, in addition to the
operational effects of the first embodiment. Specifically,
according to the present embodiment, it is possible to suppress the
frozen material generated in the further downstream-side part of
the blow-by gas reflux path 70 than the atmospheric release
mechanism 90 from being introduced into the compressor 41. Thereby,
it is possible to suppress the malfunction of the compressor 41,
which is caused when the frozen material is introduced.
Specifically, it is possible to suppress the malfunction such as a
damage of the compressor 41, which is caused when the frozen
material is introduced into the compressor 41.
[0061] Although the embodiments of the present disclosure have been
described, the present disclosure is not limited to the specific
embodiments and can be diversely modified/changed within the scope
of the present invention.
[0062] The subject application is based on Japanese Patent
Application No. 2018-078205 filed on Apr. 16, 2018, the contents of
which are incorporated herein by reference.
INDUSTRIAL APPLICABILITY
[0063] The present invention has the effect of suppressing
occurrence of oil caulking, and is useful for the blow-by gas
reflux system, the blow-by gas reflux system control device, the
storage medium, and the like.
REFERENCE SIGNS LIST
[0064] 1: internal combustion engine system [0065] 10: internal
combustion engine [0066] 20: intake passage [0067] 30: air cleaner
[0068] 40: supercharger [0069] 41: compressor [0070] 50: control
device [0071] 51: CPU (determination unit, control unit) [0072] 52:
storage unit [0073] 60: blow-by gas reflux system [0074] 70:
blow-by gas reflux path [0075] 80: oil separator [0076] 90:
atmospheric release mechanism [0077] 91: atmospheric release
passage [0078] 92: three-way valve [0079] 100a, 100b: sensor
* * * * *