U.S. patent application number 11/229531 was filed with the patent office on 2006-03-30 for oil supply device for engine.
This patent application is currently assigned to Aisin Seiki Kabushiki Kaisha. Invention is credited to Atsutoshi Ikegawa.
Application Number | 20060065217 11/229531 |
Document ID | / |
Family ID | 35447591 |
Filed Date | 2006-03-30 |
United States Patent
Application |
20060065217 |
Kind Code |
A1 |
Ikegawa; Atsutoshi |
March 30, 2006 |
Oil supply device for engine
Abstract
An oil supply device for an engine includes a first oil suction
passage, a second oil suction passage, a first pump for sucking and
discharging oil from the first oil suction passage, a second pump
arranged in series with the first pump, the second pump for sucking
and discharging oil from at least one of the first pump and the
second oil suction passage, a check valve for blocking oil
circulation, a first oil passage, a second oil passage, a third oil
passage for establishing communication between the first oil
passage and the second oil passage, and a supply volume control
device for varying oil supply volume to a lubrication system
portion, to a cooling system portion, or to the lubrication system
portion and the cooling system portion in accordance with a change
in at least one of an engine oil temperature, an engine rotation
speed, and an engine load.
Inventors: |
Ikegawa; Atsutoshi;
(Nagoya-shi, JP) |
Correspondence
Address: |
REED SMITH LLP;Suite 1400
3110 Fairview Park Drive
Falls Church
VA
22042
US
|
Assignee: |
Aisin Seiki Kabushiki
Kaisha
|
Family ID: |
35447591 |
Appl. No.: |
11/229531 |
Filed: |
September 20, 2005 |
Current U.S.
Class: |
123/41.42 ;
123/196R |
Current CPC
Class: |
F01M 1/12 20130101; F01M
1/16 20130101; F01M 1/02 20130101; F01M 5/002 20130101; F01M
2001/123 20130101 |
Class at
Publication: |
123/041.42 ;
123/196.00R |
International
Class: |
F01P 3/00 20060101
F01P003/00; F01M 1/02 20060101 F01M001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 28, 2004 |
JP |
2004-281908 |
Claims
1. An oil supply device for an engine for supplying oil to a
lubrication system portion and a cooling system portion of an
engine, comprising: a first oil suction passage in communication
with an oil reservoir which reserves oil; a second oil suction
passage in communication with the oil reservoir; a first pump for
sucking oil from the first oil suction passage by means of rotation
of crankshaft of the engine and for discharging the sucked oil; a
second pump arranged in series with the first pump for controlling
switching On-Off operation, the second pump configured to be
supplied with oil discharged from the first pump and introduced
from the second oil suction passage for sucking and discharging oil
from at least one of the first pump and the second oil suction
passage; a check valve for blocking oil circulation from the second
pump to the first pump and from the second oil suction passage to
the first pump; a first oil passage diverged between the check
valve and the first pump and extended to the lubrication system
portion; a second oil passage extended from the second pump to the
cooling system portion; a third oil passage for establishing
communication between the first oil passage and the second oil
passage; and a supply volume control means for varying oil supply
volume to the lubrication system portion, to the cooling system
portion, or to the lubrication system portion and the cooling
system portion in accordance with a change in at least one of an
engine oil temperature, an engine rotation speed, and an engine
load.
2. The oil supply device according to claim 1, wherein the supply
volume control means varies the oil supply volume to the
lubrication system portion, to the cooling system portion, or to
the lubrication system portion and the cooling system portion by
controlling switching On-Off operation of the second pump.
3. The oil supply device according to claim 2, further comprising:
a first valve provided on the third oil passage for blocking oil
circulation from the first oil passage to the second oil
passage.
4. The oil supply device according to claim 2, further comprising:
a second valve provided on the first oil passage at upstream side
relative to a connection point between the first oil passage and
the third oil passage.
5. The oil supply device according to claim 4, wherein the second
valve is a check valve for allowing oil circulation only in a
direction from the first pump to the lubrication system
portion.
6. The oil supply device according to claim 4, wherein the second
valve is an opening and closing valve for blocking oil circulation
in the first oil passage.
7. The oil supply device according to claim 4, further comprising:
a third valve provided on the first oil passage at downstream side
relative to the connection point between the first oil passage and
the third oil passage.
8. The oil supply device according to claim 7, wherein the third
valve is opened at a predetermined pressure.
9. The oil supply device according to claim 7, further comprising:
a fourth valve provided on the second oil passage at downstream
side relative to a connection point between the second oil passage
and the third oil passage.
10. The oil supply device according to claim 9, wherein the fourth
valve is a flow adjusting valve for adjusting volume of flown
oil.
11. The oil supply device according to claim 9, wherein the supply
volume control means controls an opening degree of the fourth valve
and opening and closing of the second and the third valves.
12. The oil supply device according to claim 9, wherein the supply
volume control means controls an opening degree of the fourth valve
and opening and closing of the third valve.
13. The oil supply device according to claim 9, wherein the supply
volume control means controls an opening degree of the fourth
valve.
14. The oil supply device according to claim 2, further comprising:
a third valve provided on the first oil passage at downstream side
relative to a connection point between the first oil passage and
the third oil passage.
15. The oil supply device according to claim 14, wherein the third
valve is opened at a predetermined pressure.
16. The oil supply device according to claim 14, further
comprising: a fourth valve provided on the second oil passage at
downstream side relative to a connection point between the second
oil passage and the third oil passage.
17. The oil supply device according to claim 16, wherein the fourth
valve is a flow volume-adjusting valve for adjusting volume of
flown oil.
18. The oil supply device according to claim 16, wherein the supply
volume control means controls opening and closing of the third
valve and the fourth valve.
19. The oil supply device according to claim 2, further comprising
a fourth valve provided on the second oil passage at downstream
side relative to a connection point between the second oil passage
and the third oil passage.
20. The oil supply device according to claim 19, wherein the fourth
valve is a flow volume adjusting valve for adjusting volume of
flown oil.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims priority under 35
U.S.C. .sctn.119 with respect to Japanese Patent Application No.
2004-281908 filed on Sep. 28, 2004, the entire content of which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to an oil supply device for an
engine. More particularly, the present invention pertains to an oil
supply device for an engine, which supplies oil to lubrication
system portions and cooling system portions of the engine.
BACKGROUND
[0003] A known oil supply device for an engine described in JPH04
(1992)-132414U includes a main oil pump (i.e., a first pump) and a
motor driven oil pump (i.e., a second pump). According to the known
oil supply device, a destination of oil from each pump is changed
by appropriately switching oil passages from the both pumps on the
basis of engine rotation speed. With the known oil supply device
described in JPH04 (1992)-132414U, the first pump and the second
pump are arranged in parallel from each other relative to a
destination of oil, and oil supplied from the oil pumps is used
mainly for hydraulic pressure actuation.
[0004] According to another oil supply device for an engine
described in JPH10 (1998)-252434, a first pump and a second pump
are arranged in series relative to a destination of oil. With this
oil supply device, oil sucked from an oil reservoir is discharged
by the first pump to the second pump side, and the second pump
discharges the oil discharged from the first pump to the
destination of the oil.
[0005] Lubrication system portions such as a cam and a cam chain,
which require supply of oil for lubrication and cooling system
portions such as a piston, which require supply of oil for cooling
require oil supply at engine in addition to the aforementioned
portions related to the hydraulic pressure actuation. However,
because whether it is necessary to supply oil to the lubrication
system portions and the cooling system portions is varied in
accordance with temperature of oil and spattered volume of oil
(amount of oil mist) and further because there is adequacy of an
oil pump used for supplying oil to each portion (e.g., a pump with
larger output torque is required when oil viscosity is higher), oil
cannot be supplied appropriately to the lubrication system portion
and the cooling system portion with known oil supply devices where
oil passages are switched on the basis of only the engine rotation
speed.
[0006] Further, with the construction of the oil supply device
according to JPH04 (1992)-132414U, because the main oil pump and
the electric oil pump are arranged in parallel to the destination
of the oil, there is an drawback that the both pumps should be high
output pumps when it is necessary to supply oil by high pressure
relative to the destination of the oil. Further, with the
construction of the oil supply device according to JPH10
(1998)-252434, the second pump cannot suck oil unless the first
pump is operated, and thus the second pump cannot supply the oil to
the destination of the oil. Particularly, there is a drawback that
oil cannot be supplied from the second pump to the destination of
the oil until the first pump sufficiently sucks oil and discharge
the oil to the second pump at an engine start.
[0007] A need thus exists for an oil supply device of an engine,
which appropriately supplies oil to a necessary portion.
SUMMARY OF THE INVENTION
[0008] In light of the foregoing, the present invention provides an
oil supply device for an engine for supplying oil to a lubrication
system portion and a cooling system portion of an engine, which
includes a first oil suction passage in communication with an oil
reservoir which reserves oil, a second oil suction passage in
communication with the oil reservoir, a first pump for sucking oil
from the first oil suction passage by means of rotation of
crankshaft of the engine and for discharging the sucked oil, a
second pump arranged in series with the first pump for controlling
switching On-Off operation, the second pump configured to be
supplied with oil discharged from the first pump and introduced
from the second oil suction passage for sucking and discharging oil
from at least one of the first pump and the second oil suction
passage, a check valve for blocking oil circulation from the second
pump to the first pump and from the second oil suction passage to
the first pump, a first oil passage diverged between the check
valve and the first pump and extended to the lubrication system
portion, a second oil passage extended from the second pump to the
cooling system portion, a third oil passage for establishing
communication between the first oil passage and the second oil
passage, and a supply volume control means for varying oil supply
volume to the lubrication system portion, to the cooling system
portion, or to the lubrication system portion and the cooling
system portion in accordance with a change in at least one of an
engine oil temperature, an engine rotation speed, and an engine
load.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The foregoing and additional features and characteristics of
the present invention will become more apparent from the following
detailed description considered with reference to the accompanying
drawings, wherein:
[0010] FIG. 1 is a schematic diagram of an oil supply device
according to a first embodiment of the present invention.
[0011] FIG. 2 is a partial schematic diagram of an oil supply
device according to a second embodiment of the present
invention.
[0012] FIG. 3 is a partial schematic diagram of an oil supply
device according to a third embodiment of the present
invention.
[0013] FIG. 4 is a partial schematic diagram of an oil supply
device according to a fourth embodiment of the present
invention.
[0014] FIG. 5 is a partial schematic diagram of an oil supply
device according to a fifth embodiment of the present
invention.
[0015] FIG. 6 is a partial schematic diagram of an oil supply
device according to a sixth embodiment of the present
invention.
[0016] FIG. 7 is a partial schematic diagram of an oil supply
device according to a seventh embodiment of the present
invention.
DETAILED DESCRIPTION
[0017] Embodiments of an oil supply device for an engine according
to the present invention will be explained with reference to
illustrations of drawing figures as follows.
[0018] As shown in FIG. 1, an oil supply device for an engine
according to a first embodiment of the present invention includes
an oil supply circuit which includes a lubrication system portion
10 where oil for lubrication is supplied in the engine and a
cooling system portion 11 where the oil for cooling is supplied.
For example, the lubrication system portion 10 includes a cam
shower for showering oil for lubrication to a cam, and a chain jet
for jetting oil for oil to a cam chain, or the like. The cooling
system portion 11, for example, includes a piston jet for jetting
cooling oil to a piston.
[0019] According to this oil supply circuit, oil is supplied to the
lubrication system portion 10 and the cooling system portion 11
from either a first oil reservoir 3 or a second oil reservoir 4.
More particularly, the oil supply circuit includes a first pump 1
and a second pump 2 for discharging oil to the lubrication system
portion 10 and the cooling system portion 11 by sucking oil from
the first oil reservoir 3 and the second oil reservoir 4. As shown
in FIG. 1, in order to promptly supply the oil to the second pump
2, it is preferable that the second oil reservoir 4 provided
separately from the first oil reservoir 3 is arranged in the
vicinity of the second pump 2. However, the first oil reservoir 3
and the second oil reservoir 4 may be provided unitarily.
[0020] According to the embodiment of the present invention, a
mechanical oil pump driven by rotation of a crankshaft of an engine
serves as the first pump 1. An electric oil pump whose output oil
volume and ON-OFF operation are controlled by controlling actuation
of a motor M serves as the second pump 2. By applying the electric
oil pump as the second pump 2, for example, discharged volume of
oil at the first pump 1 can be compensated by operating the second
pump when the first pump is not sufficiently functioned, for
example, at immediately after the engine start. Further, oil can be
supplied to the lubrication portion 10 by operating the second pump
2 even before the engine start. In that case, because the engine is
started at a state where the oil is sufficiently supplied to the
lubrication system portion 10, friction at each portion of the
engine declines, and abrasion of parts can be prevented. The second
pump allows to set the first pump to have less oil discharging
performance. Accordingly, the first pump, which is the mechanical
oil pump, is reduced in size and friction of the engine can be
declined.
[0021] The first pump 1 is connected to a first oil suction passage
18 for sucking oil from the first oil reservoir 3, and the oil
sucked from the first oil reservoir 3 is discharged from the first
pump 1 to flow in a first oil filter 8. The oil passes through the
first oil filter 8 so that foreign materials are removed from the
oil and is supplied to the lubrication system portion 10 through
the first oil passage 5. When the second pump 2 is actuated, the
oil which has passed through the first oil filter 8 is sucked to be
introduced to a second oil passage 6, and is discharged from the
second pump 2 to flow in the second oil filter 9. The oil passes
through the second oil filter 9 so that foreign materials are
removed from the oil and is supplied to the cooling system portion
11 or to the cooling system portion 11 and the lubrication system
portion 10 through the second oil passage 6.
[0022] The second pump 2 sucks the oil which has passed through the
first oil filter 8 to discharge to the second oil passage 6 when
the first pump 1 is actuated. However, for example, when the oil
discharge volume from the first pump 1 is not sufficiently, for
example, at immediately after the engine start, it is not easy that
the second pump 2 pumps oil from the first oil reservoir 3 through
the first pump 1. Thus, with the construction of the embodiment of
the present invention, oil is sucked from the second oil reservoir
4 which is provided separately from the first oil reservoir 3
through a second oil suction passage 19. The oil supply device
according to the embodiment of the present invention includes a
check valve 13 provided at the first pump 1 side relative to a
connecting point between the second oil passage 6 and the second
oil suction passage 19 in order to prevent oil sucked by the second
oil pump 2 from flowing in reverse to the first pump 1 side.
Further, the oil supply device also includes a check valve 12 on
the second oil suction passage 19 in order to prevent the oil
supplied from the first pump 1 to the second pump 2 from flowing in
reverse to the second oil reservoir 4 side. With the construction
of the embodiment of the present invention, the second pump 2 can
compensate the first pump 1 at any timing.
[0023] As foregoing, because the first pump 1 and the second pump 2
are arranged in series so that the second pump 2 sucks the oil
discharged from the first pump 1, hydraulic pressure at suction
side of the second pump 2 assumes the hydraulic pressure which is
supplied from the first pump 1, and oil can be sucked with less
power than the oil is sucked only by the second pump 2.
Accordingly, with the construction of the embodiment of the present
invention, the second pump 2 can be reduced in size and the output
from the second pump per se can be reduced. Because the second pump
2 can output the oil by further increasing oil pressure of the oil
discharged from the first pump 1 with smaller power, the
construction of the embodiment of the present invention is
particularly advantageous for a case where the second pump 2
supplies oil to the cooling system portion 11 such as the oil jet
where large volume and high pressured oil is required to be
supplied.
[0024] Further, because the first oil suction passage 18 and the
second oil suction passage 19 are arranged in parallel each other
relative to the second pump 2, oil introduced from the first oil
suction passage 18 and discharged from the first pump 1 and oil
introduced from the second oil suction passage 19 is supplied to
the second pump 2. Accordingly, for example, the second pump 2
alone can suck the oil from the second oil suction passage 19
provided in parallel to the first oil suction passage 18 to
discharge appropriate volume of oil even when the first pump 1 is
not filled up with the oil because the first pump 1 has not
sufficiently sucked oil from the first oil suction passage 18, for
example, at immediately after the engine start.
[0025] Instead of providing the first oil filter 8 and the second
oil filter 9, oil filters may be provided at an end portion of the
first oil suction passage 18 for sucking the oil from the first oil
reservoir 3 and at an end portion of the second oil suction passage
19 for sucking the oil from the second oil reservoir 4.
[0026] A third oil passage 7 for establishing the communication
between the first oil passage 5 extended from the first pump 1 to
the lubrication system portion 10 and the second oil passage 6
extended from the second pump 2 to the cooling system portion 11 is
provided between the first oil passage 5 and the second oil passage
6. A first valve 14 (e.g., a check valve) for blocking an oil
circulation from the first oil passage 5 to the second oil passage
6 through the third oil passage 7 and for allowing the oil
circulation from the second oil passage 6 to the first oil passage
5 through the third oil passage 7 is provided on the third oil
passage 7. A second valve 16 (e.g., a check valve) for allowing oil
circulation only towards the lubrication system portion 10 is
provided on the first oil passage 5 at upstream side relative to a
connection point between the first oil passage 5 and the third oil
passage 7.
[0027] Further, a third valve 17 (e.g., stop valve) is provided on
the first oil passage 5 at downstream side of a connection point of
the first oil passages 5 and the third oil passage 7 for allowing
oil circulation when oil pressure is lower than a predetermined
pressure and oil temperature is lower than a predetermined
temperature and for stopping oil circulation when oil pressure is
equal to or higher than a predetermined pressure and oil
temperatures is equal to or lower than a predetermined temperature.
A predetermined temperature and a predetermined pressure are
determined in accordance with engine characteristics and parts of
the engine, or the like. A fourth oil passage 20 is diverged from
the first oil passage 5 at upstream side relative to the second
valve 16 for supplying oil to other portions such as a crankshaft
bearing portion and a camshaft bearing portion, or the like.
[0028] A fourth valve 15 which adjusts oil volume to the cooling
system portion 11 is provide on the second oil passage 6 at
downstream side of a connection point between the second oil
passage 6 and the third oil passage 7. By controlling opening
degree of the fourth valve 4, a destination and volume of oil to be
supplied, the oil being discharged from the second pump 2 and
circulated in the second oil passage 6 can be controlled. For
example, oil which is discharged from the second pump 2 and
circulated in the second oil passage 6 is supplied only to the
lubrication system portion 10 through the third oil passage 7 when
the fourth valve 15 is closed. When the fourth valve 15 is open,
oil can be distributed to the lubrication system portion 10 and the
cooling system portion 11.
[0029] The oil supply device according to the embodiment of the
present invention includes an electronic control unit (ECU) 21 for
detecting and outputting control signal of an engine rotation
speed, a load signal of an engine, an engine oil temperature, and a
water temperature of cooling water. Control signal from the ECU 21
is transmitted to the motor M and the fourth valve 15, and
operation of the motor M and opening degree of the fourth valve 15
are controlled.
[0030] The ECU 21 serving as a supply volume control means conducts
a supply volume changing control for changing oil supply volume
from the second pump 2 to the lubrication system portion 10, to the
cooling system portion 11, or to the lubrication system portion 10
and the cooling system portion 11 in accordance with changes of at
least one of engine oil temperature, engine rotation speed, and
engine load. Referring to FIG. 1 and Table 1, a control for opening
degree of the fourth valve 15 and a control for the operation of
the motor M by the ECU 21 will be explained as follows.
TABLE-US-00001 TABLE 1 Oil temperature Rotation speed / Load Equal
to or higher Lower than than predetermined predetermined value
value Cooling system Lower than A: No B: No portion predetermined
value Equal to or higher C: No D: Yes (electric oil than
predetermined pump) value Lubrication system Lower than E: Yes F:
Yes (electric oil portion predetermined value pump) Equal to or
higher G: Yes H: No portion than predetermined value
[0031] Oil supply to the cooling system portion is, first,
explained with reference to Table 1. When an engine oil temperature
is lower than a predetermined temperature, oil for cooling is not
supplied to the cooling system portion 11 in order to avoid
needless cooling of the cooling system portion 11 (i.e.,
corresponding to A and C in Table 1). In this case, even if the oil
is supplied to the lubrication system portion 10 through the first
oil passage 5 from the first pump 1, the oil is not supplied to the
cooling system portion 11 from the first oil passage 5 through the
third oil passage 7 because of the first valve 14 provided at the
third oil passage 7.
[0032] On the other hand, when an engine oil temperature is equal
to or higher than a predetermined temperature and engine rotation
speed and engine load is relatively large, the cooling system
portion 11 exposed to thermally severe environment is cooled
(corresponding to D in Table 1). Because the viscosity of oil is
low, in this case, the ECU 21 supplies oil to the cooling system
portion 11 by the second pump 2 which can control operation of the
oil supply device and discharged oil volume, and sets the fourth
valve 15 at a predetermined opening degree. Thresholds for the
engine rotation speed and engine load when the second pump 2 is
operated is set in accordance with an engine characteristics and
characteristics of engine parts.
[0033] When an engine oil temperature is equal to or higher than a
predetermined temperature and engine rotation speed and engine load
are relatively small, it is not necessary to cool the engine
actively. In this case, the oil supply to the cooling system
portion 11 by the second pump 2 is stopped (i.e., corresponding to
B in Table 1). In this regard, it is necessary to supply oil to the
lubrication system portion 10 by operating the second pump 2 even
when the engine oil temperature is equal to or higher than a
predetermined temperature and the engine rotation speed and engine
load are at relatively low level. Thus, the ECU 21 stops supply of
the oil to the cooling system portion 11 by closing the fourth
valve 15.
[0034] Regarding oil supply to the lubrication system portion 10
shown in Table 1, when an engine oil temperature is lower than a
predetermined temperature, it is favorable to supply oil for
lubrication to the lubrication system portion 10 (i.e.,
corresponding to E and G in Table 1) because oil viscosity is high
and spattered volume of the oil is small. In this case, the ECU 21
supplies oil to the lubrication system portion 10 by the first pump
1 which is a mechanical oil pump which enables to output larger
torque and not by the second pump 2 which is an electric oil pump
considering high viscosity of the oil.
[0035] When an engine oil temperature is equal to or higher than a
predetermined temperature and engine rotation speed and engine load
are relatively small, spattered volume of the oil assumes less
whereas the oil viscosity is low. Thus, oil for lubrication is
supplied to the lubrication system portion 10. In this case,
because the oil viscosity is low, large torque is not necessary for
discharging the oil. The ECU 21 supplies oil to the lubrication
system portion 10 by the second pump 2, accordingly (i.e.,
corresponding to F in Table 1). In this regard, volume of oil to be
supplied could be much less. Thus, for example, supply pressure of
oil to the lubrication system portion 10 is set at lower pressure
than supply pressure of oil to the cooling system portion 11. When
an engine oil temperature is equal to or higher than a
predetermined temperature and engine rotation speed and engine load
are relatively large, oil viscosity assumes lower and spattered
volume of oil (amount of oil mist) is increased, in this case,
accordingly, it is not necessary to supply oil for lubrication to
the lubrication system portion 10 (i.e., corresponding to H in
Table 1).
[0036] More particularly, when an engine oil temperature is equal
to or higher than a predetermined temperature, the ECU 21 serving
as a supply volume control means conducts a supply volume change
control for increasing oil supply to the cooling system portion 11
in accordance with an increase of engine load and engine rotation
speed (i.e., corresponding to D in Table 1). When an engine oil
temperature is changed to be equal to or higher than a
predetermined temperature at a state where, for example, engine
rotation speed is high and engine load is large, the ECU 21
operates the motor M to operate the second pump 2 (e.g., the
electric oil pump) to circulate oil to the second oil passage 6. In
this case, because oil temperature and oil pressure are equal to or
higher than predetermined values respectively, the third valve
(stop valve) 17 is closed to stop oil supply to the lubrication
system portion 10. Accordingly, oil for cooling is selectively
supplied to the cooling system portion 11 to cool the cooling
system portion 11.
[0037] Because oil viscosity is declined at a state where an engine
oil temperature is equal to or higher than a predetermined
temperature, spattered volume of oil (amount of oil mist) is
increased at the lubrication system portion 10, for example, when
engine rotation speed and engine load are large. Thus, it is not
necessary that oil for lubrication is supplied to the lubrication
system portion 10 by using an oil pump. On the other hand, when an
engine oil temperature is less than a predetermined temperature,
the ECU 21 stops the motor M not to supply oil to the cooling
system portion 11, and unnecessary energy consumption is
restrained.
[0038] The ECU 21 conducts a supply volume change control for
reducing oil supply volume to the lubrication system portion 10 in
accordance with an increase of an engine rotation speed and engine
load. More particularly, when, for example, engine rotation speed
and engine load are small at a state where an engine oil
temperature is equal to or higher than a predetermined temperature,
the ECU 21 supplies oil to the lubrication system portion 10 by
operating the second pump 2 serving as the electric oil pump. When
engine rotation speed and engine load are increased at a state
where an engine oil temperature is equal to or higher than a
predetermined temperature, the ECU 21 conducts a control for
reducing oil supply volume to the lubrication system portion 10 by
closing the third valve 17. That is, when engine rotation speed and
engine load are increased at a state where an engine oil
temperature is equal to or higher than a predetermined temperature,
spattered volume of oil (amount of oil mist) is increased.
Accordingly, oil supply to the lubrication system portion 10 is
stopped, and appropriate volume of oil is supplied to the cooling
system portion 11. Thus, when an engine oil temperature is equal to
or higher than a predetermined temperature, the ECU 21 conducts
supply volume changing control for changing a destination of oil
through the oil pump from the lubrication system portion 10 to the
cooling system portion 11.
[0039] A second embodiment of the present invention will be
explained as follows. Although, according to the first embodiment
of the present invention, as shown in FIG. 1, the first valve 14
(i.e., check valve) is provided on the third oil passage 7, and the
second valve 16 (i.e., check valve) is provided on the first oil
passage 5 at the upstream side relative to the connection point
between the first oil passage 5 and the third oil passage 7, and
the third valve 17 (i.e., stop valve) is provided on the first oil
passage 5 at the downstream side relative to the connection point
between the first oil passage 5 and the third oil passage 7,
construction of each valve can be varied. According to the second
embodiment of the present invention, as shown in FIG. 2, a third
valve 27 (i.e., opening and closing valve) may be provided instead
of the stop valve. The ECU 21 commands to open the third valve 27
when supplying oil for lubrication to the lubrication system
portion 10 by the first pump 1 and when supplying oil for
lubrication to the lubrication system portion 10 by the second pump
2. Further, the ECU 21 commands to close the third valve 27 and to
open the fourth valve 15 so that oil is not supplied to the
lubrication system portion 10 when supplying oil for cooling only
to the cooling system portion 11 by the second pump 2. Other
construction of the oil supply device according to the second
embodiment is common to the first embodiment, and thus explanation
thereof is not repeated.
[0040] A third embodiment of the present invention will be
explained with reference to FIG. 3. According to the third
embodiment of the present invention, as shown in FIG. 3, a third
valve 27 (i.e., a opening and closing valve) is provided on the
first oil passage 5 at the upstream side of the connection point
between the first oil passage 5 and the third oil passage 7 instead
of the check valve, a third valve 27 (i.e., opening and closing
valve) is provided on the first oil passage 5 at the downstream
side of the connection point between the first oil passage 5 and
the third oil passage 7 instead of the stop valve, and the first
valve 14 shown in FIG. 1 is not provided. The ECU 21 commands to
open the second valve 26 and the third valve 27 and to close the
fourth valve 15 for supplying oil for lubrication only to the
lubrication system portion 10 by the first pump 1. The ECU 21
commands to open the third valve 27 and to close the fourth valve
15 and the second valve 26 for supplying oil only to the
lubrication system portion 10 by the second pump 2. Further, the
ECU 21 commands to open the fourth valve 15 and to close the second
valve 26 and the third valve 27 for supplying oil for cooling only
to the cooling system portion 11 by the second pump 2. The ECU 21
also commands to close the second valve 26 and to open the fourth
valve 15 and the third valve 27 for supplying oil for lubrication
to the lubrication system portion 10 by the second pump 2 and for
supplying oil for cooling to the cooling system portion 11.
Accordingly, by using valves which can adjust opening degree as the
second valve 26, the third valve 27 and the fourth valve 15, oil
supply volume to the lubrication system portion 10 and the cooling
system portion 11 can be optimally adjusted in accordance with
operational state of the engine. Other construction of the oil
supply device according to the third embodiment is common to the
first embodiment, and thus explanation thereof is not repeated.
[0041] A fourth embodiment of the present invention will be
explained as follows. According to the fourth embodiment of the
present invention, the first valve 14 shown in FIG. 1 is not
provided on the third oil passage 7. The ECU 21 commands to close
the fourth valve 15 when supplying oil for lubrication only to the
lubrication system portion 10 using either the both of the first
pump 1 and the second pump 2 or either one of the first pump 1 or
the second pump 2. Other construction of the oil supply device
according to the fourth embodiment is common to the first
embodiment, and thus explanation thereof is not repeated.
[0042] A fifth embodiment of the present invention will be
explained as follows. According to the fifth embodiment of the
present invention, the third valve 27 (i.e., opening and closing
valve) is provided likewise the second embodiment of the present
invention instead of the stop valve, and the first valve 14 is not
provided on the third oil passage 7. With this construction, oil
can be circulated freely between the first oil passage 5 and the
second oil passage 6. Accordingly, oil volume supplied to the
lubrication system portion 10 and the cooling system portion 11 is
controlled by constantly adjusting the third valve 27 and the
fourth valve 15. For example, the ECU 21 commands to open the third
valve 27 and to close the fourth valve 15 when supplying oil for
lubrication only to the lubrication system portion 10 using either
the both of the first pump 1 and the second pump 2 or either one of
the first pump 1 or the second pump 2. Further, when supplying oil
for cooling only to the cooling system portion 11, the fourth valve
15 is opened and the third valve 27 is closed. When supplying oil
to the lubrication system portion 10 and the cooling system portion
11, opening degree of the fourth valve 15 and the third valve 27
are adjusted.
[0043] A sixth embodiment of the present invention will be
explained with reference to FIG. 6 as follows. According to the
sixth embodiment of the present invention, plural check valves and
stop valves applied in the first embodiment for supplying oil are
replaced with a oil passage switching valve 30 operated by the oil
pressure. With this construction, the number of parts can be
reduced. Operation of the oil supply device according to the sixth
embodiment of the present invention is as follows. First, when the
ECU 21 stops the second pump 2, operational oil is supplied to the
lubrication system portion 10 from the first pump 1. The ECU 21
operates the second pump 2 with low pressure where oil discharged
at low pressure when engine rotation speed is low and an engine oil
temperature is high. As a result, when the second pump 2 is
operated at the low pressure, oil pressure from the second pump 2
affects an oil pressure actuation portion 33, and moves a spool
valve biased by the spring 32 to the left of FIG. 6, and operation
oil from the second pump 2 is supplied to the lubrication system
portion 10. The ECU 21 operates the second pump 2 with high
pressure when an engine rotation speed is high and an engine oil
temperature is high. Accordingly, when the second pump 2 operates
to discharge high pressured oil, an adjusting pressure valve 31 is
closed at a state where the spool valve is moved to the left in
FIG. 6 by the oil pressure from the second pump 2, and operational
oil from the second pump 2 is supplied to the cooling system
portion 11. Other construction of the oil supply device according
to the sixth embodiment is common to the first embodiment, and thus
explanation thereof is not repeated.
[0044] A seventh embodiment of the present invention will be
explained with reference to FIG. 7. According to the seventh
embodiment of the present invention, the oil pressure actuation
portion 33 according to the sixth embodiment is replaced with a
shape memory spring 43. An operation of the oil supply device
according to the seventh embodiment of the present invention is as
follows. First, when the ECU 21 stops the second pump 2,
operational oil is supplied from the first pump 1 to the
lubrication system portion 10. The ECU 21 operates the second pump
2 with low pressure for discharging oil when engine rotation speed
is low and an engine oil temperature is high. As a result, the
shape memory spring 43 is expanded by oil temperature of the
operational oil, the spool valve biased by a spring 32 is moved to
the left in FIG. 7, and operational oil from the second pump 2 is
supplied to the lubrication system portion 10. The ECU 21 operates
the second pump 2 with high pressure to discharge high-pressured
oil when engine rotation speed is high and an engine oil
temperature is high. Accordingly, when the second pump 2 is
operated at high pressure, because the shape memory spring 43 is
expanded at the spool valve, the adjusting pressure valve 31 is
closed at a state where the spool valve is moved to the left by the
oil pressure from the second pump 2, and operational oil from the
second pump 2 is supplied to the cooling system portion 11.
[0045] According to the embodiment of the present invention, the
supply volume control means can change oil supply volume from the
oil pump to the lubrication system portion, to the cooling system
portion, or to the lubrication system portion and the cooling
system portion in accordance with operational state of the engine,
for example, at least one of change of oil temperature of the
engine, engine rotation speed, and engine load.
[0046] According to the embodiment of the present invention, the
oil pump of the oil supply device includes the first pump for
utilizing rotation of the crankshaft of the engine and the second
pump which controls to switch operation of the oil supply device.
The first pump is configured to output torque to easily discharge
oil with relatively high viscosity, and can supply oil to the
lubrication system portion even when oil temperature is low and oil
viscosity is high. By switching On-Off of the operation of the
second pump 2 in accordance with an operational state of the
engine, optimum volume of oil can be supplied to the lubrication
portion and to the cooling system portion in accordance with
operational state of the engine. Thus, because oil supply volume
can be changed freely, engine efficiency can be increased by
preventing oil supply to unnecessary portion and by supplying
appropriate volume of oil to necessary portions.
[0047] According to the embodiment of the present invention, the
first valve is provided to block circulation of oil from the first
oil passage to the second oil passage. By preventing supply of oil
at the first oil passage to the cooling system portion, for
example, it can be prevented that oil is supplied to the cooling
system portion from the first pump at low oil temperature and at
low engine rotation speed. As a result, for example, when the
cooling portion is a piston, a piston bore is not unnecessarily
cooled. Accordingly, because warm-up of the engine at the start of
the engine is promoted and engine friction is declined promptly,
fuel injection volume is reduced, and thus and engine with high
thermal efficiency which improves mileage can be obtained.
[0048] According to the embodiment of the present invention,
because the second pump is arranged in series with the first pump,
and is arranged to suck oil discharged from the first pump, oil
pressure at suction side of the second pump assumes oil pressure
supplied from the first pump, and oil can be sucked with less power
than power for sucking oil by the second pump alone. Accordingly,
output of the second pump per se can be reduced and the second pump
can be reduced in size. By arranging the second pump and the first
pump in series, the second pump can output oil discharged from the
first pump by further increasing the pressure with less power, and
thus, it is advantageous when the second pump supplies oil to a
destination of the oil such as an oil jet which requires large
volume and high pressured oil.
[0049] Further, according to the embodiment of the present
invention, because oil discharged from the first pump and oil
introduced from the second oil suction passage is supplied to the
second pump, the second pump alone can suck oil from the second oil
suction passage even when oil is not filled up in the first pump
and piping because the first pump has not sufficiently sucked oil
discharged from the first pump through the first oil suction
passage, for example, at immediately after the engine start.
[0050] According to the embodiment of the present invention, when
oil is supplied to the lubrication system portion from the second
pump, reverse circulation of oil, which has circulated into the
first oil passage from the second oil passage through the third oil
passage, to the first pump side is blocked. Thus, oil can be
securely supplied to the lubrication system portion. Further, when
switching ON-OFF of the operation of the second pump, oil supply to
the lubrication system portion by the first pump is not interrupted
and oil is supplied at engine smoothly.
[0051] When engine rotation speed is increased, volume of oil
spattered inside a crankcase is increased. With the foregoing
state, for example, lubricating the lubrication system portion such
as the cam shower and the chain jet can be sufficiently completed
by spattering oil. Thus, further oil supply, in this case, from the
pump to the lubrication system portion becomes operational
resistance of parts of the engine. With the construction of the
embodiment of the present invention, accordingly, the third valve
configured to close when pressure of oil discharged from the first
pump or the second pump is increased to be equal to or higher than
a predetermined pressure is provided at downstream side relative to
the connection point between the first oil passage and the third
oil passage. Thus, when volume of the oil spattered inside the
crankcase is increased because of increase of engine rotation
speed, the third valve is closed, further oil supply to the
lubrication system portion is stopped, and a decline of the engine
efficiency can be effectively prevented.
[0052] According to the embodiment of the present invention, by
controlling opening degree of the fourth valve, volume of oil to be
supplied and a destination of oil to be supplied which has
discharged from the second pump and circulated in the second oil
passage can be controlled. For example, oil discharged from the
second pump and circulated in the second oil passage is supplied
only to the lubrication system portion through the third oil
passage when the fourth valve is closed. When the fourth valve is
open, oil discharged from the second pump and circulated in the
second oil passage is distributed to the lubrication system portion
and the cooling system portion. Accordingly, by controlling opening
degree of the fourth valve, oil volume supplied to the lubrication
system portion and oil volume supplied to the cooling system
portion can be controlled.
[0053] The principles, preferred embodiment and mode of operation
of the present invention have been described in the foregoing
specification. However, the invention which is intended to be
protected is not to be construed as limited to the particular
embodiments disclosed. Further, the embodiments described herein
are to be regarded as illustrative rather than restrictive.
Variations and changes may be made by others, and equivalents
employed, without departing from the spirit of the present
invention. Accordingly, it is expressly intended that all such
variations, changes and equivalents which fall within the spirit
and scope of the present invention as defined in the claims, be
embraced thereby.
* * * * *