U.S. patent application number 11/649820 was filed with the patent office on 2009-04-23 for valve timing control device.
This patent application is currently assigned to AISIN SEIKI KABUSHIKI KAISHA. Invention is credited to Kazumi Ogawa, Mitsuru Uozaki.
Application Number | 20090101093 11/649820 |
Document ID | / |
Family ID | 38170095 |
Filed Date | 2009-04-23 |
United States Patent
Application |
20090101093 |
Kind Code |
A1 |
Ogawa; Kazumi ; et
al. |
April 23, 2009 |
VALVE TIMING CONTROL DEVICE
Abstract
A valve timing control device includes a driving side rotational
member, a driven side rotational member, a retarded angle chamber,
an advanced angle chamber, a first control valve, a supply passage
supplying the fluid to the first control valve, a first pump
pumping the fluid to a vapor liquid separating portion, a second
pump pumping the fluid in the vapor liquid separating portion to
the first control valve, a discharge passage discharging the fluid
from the first control valve toward the operational fluid
reservoir, and a second control valve provided at the discharge
passage and operated to switch the discharge passage between a
first discharge passage is discharging the fluid discharged from
the first control valve to the operational fluid reservoir and a
second discharge passage flowing the fluid to be drawn into the
first pump.
Inventors: |
Ogawa; Kazumi; (Toyota-shi,
JP) ; Uozaki; Mitsuru; (Frankfurt am Main,
DE) |
Correspondence
Address: |
BUCHANAN, INGERSOLL & ROONEY PC
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
AISIN SEIKI KABUSHIKI
KAISHA
Kariya-shi
JP
|
Family ID: |
38170095 |
Appl. No.: |
11/649820 |
Filed: |
January 5, 2007 |
Current U.S.
Class: |
123/90.17 |
Current CPC
Class: |
F01L 2001/34473
20130101; F01L 2001/34446 20130101; F01L 2001/34456 20130101; F01L
2001/3443 20130101; F01L 1/3442 20130101; Y10T 137/8671 20150401;
F01L 2001/34453 20130101 |
Class at
Publication: |
123/90.17 |
International
Class: |
F01L 1/352 20060101
F01L001/352 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 10, 2006 |
JP |
2006-002312 |
Claims
1. A valve timing control device, comprising: a driving side
rotational member synchronously rotating with a crankshaft of an
internal combustion engine; a driven side rotational member
arranged coaxially with the driving side rotational member and
rotatable relative to the driving side rotational member, the
driven side rotational member rotating integrally with a camshaft
for opening and closing valves for the internal combustion engine;
a retarded angle chamber formed by the driving side rotational
member and the driven side rotational member and displacing a
relative rotational phase of the driven side rotational member
relative to the driving side rotational member in a retarded angle
direction; an advanced angle chamber formed by the driving side
rotational member and the driven side rotational member and
displacing the relative rotational phase of the driven side
rotational member relative to the driving side rotational member in
an advanced angle direction; a first control valve controlling
supply and discharge states of an operational fluid between an
operational fluid reservoir provided at a lower portion of the
internal combustion engine and the advanced angle chamber and the
retarded angle chamber; a supply passage supplying the operational
fluid from the operational fluid reservoir to the first control
valve; a first pump provided at the supply passage and pumping the
operational fluid in the operational fluid reservoir to a vapor
liquid separating portion; a second pump provided at the supply
passage and pumping the operation fluid in the vapor liquid
separating portion to the first control valve; a discharge passage
discharging the operational fluid from the first control valve
toward the operational fluid reservoir; and a second control valve
provided at the discharge passage and operated to selectively
switch the discharge passage between a first discharge passage
discharging the operational fluid discharged from the first control
valve to the operational fluid reservoir and a second discharge
passage flowing the operational fluid to be drawn into a drawing
portion of the first pump.
2. A valve timing control device according to claim 1, further
comprising: a controlling means switching the discharge passage to
the second discharge passage immediately after a start of the
internal combustion engine and switching the discharge passage to
the first discharge passage once a predetermined condition is
satisfied after the engine starts.
3. A valve timing control device, comprising: a driving side
rotational member synchronously rotating with a crankshaft of an
internal combustion engine; a driven side rotational member
arranged coaxially with the driving side rotational member and
rotatable relative to the driving side rotational member, the
driven side rotational member rotating integrally with a camshaft
for opening and closing valves for the internal combustion engine;
a retarded angle chamber formed by the driving side rotational
member and the driven side rotational member and displacing a
relative rotational phase of the driven side rotational member
relative to the driving side rotational member in a retarded angle
direction; an advanced angle chamber formed by the driving side
rotational member and the driven side rotational member and
displacing the relative rotational phase of the driven side
rotational member relative to the driving side rotational member in
an advanced angle direction; a first control valve controlling
supply and discharge states of an operational fluid between an
operational fluid reservoir provided at a lower portion of the
internal combustion engine and the advanced angle chamber and the
retarded angle chamber; a supply passage supplying the operational
fluid from the operational fluid reservoir to the first control
valve; a pump provided at the supply passage and supplying the
operation fluid in the operational fluid reservoir to the first
control valve; a discharge passage discharging the operational
fluid from the first control valve toward the operational fluid
reservoir; and a second control valve provided at the discharge
passage and operated to selectively switch the discharge passage
between a first discharge passage discharging the operational fluid
discharged from the first control valve to the operational fluid
reservoir and a second discharge passage flowing the operational
fluid to be drawn into a drawing portion of the first pump.
4. A valve timing control device according to claim 3, further
comprising a controlling means controlling the second control valve
to switch the discharge passage to the second discharge passage
immediately after a start of an internal combustion engine and
switching the discharge passage to the first discharge passage once
a predetermined condition is satisfied after the engine starts.
5. A valve timing control device according to claim 2, wherein a
predetermined condition is a temperature of either one of the
operational fluid and a coolant of the internal combustion
engine.
6. A valve timing control device according to claim 5, wherein the
predetermined condition is a time period set preliminarily.
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
2006-002312, filed on Jan. 10, 2006, the entire content of which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to a valve timing control device.
More particularly, this invention relates to a valve timing control
device which includes a driving side rotational member
synchronously rotating relative to a crankshaft of an internal
combustion engine, a driven side rotational member positioned
coaxially to the driving side rotational member and rotatable
relative to the driving side rotational member, the driven side
rotational member synchronously rotating relative to a camshaft for
opening and closing valves of the internal combustion engine, a
retarded angle chamber formed by the driving side rotational member
and the driven side rotational member and displacing a relative
rotational phase of the driven side rotational member relative to
the driving side rotational member in a retarded angle direction,
an advanced angle chamber displacing the relative rotational phase
in an advanced angle direction, and a first change valve
controlling the supply and the discharge state of an operational
fluid among the advanced angle chamber, the retarded angle chamber
and an operational fluid reservoir provided at a lower portion of
the internal combustion engine.
BACKGROUND
[0003] A valve timing control device operates in synchronization
with a crankshaft and a camshaft of an engine, which is an internal
combustion engine. A relative rotational phase of the valve timing
control device can be changed or set by control of the relative
rotational position between an advanced angle chamber and a
retarded angle chamber, which are provided between the driven side
rotational member and the driving side rotational member
respectively. Then, a preferable operating state can be attained by
properly setting the relative rotational phase in response to an
operating state of the engine.
[0004] A hydraulic pump supplies and discharges an operational
fluid to fluid pressure chambers of the valve timing control device
and is driven by the crankshaft of the engine. Thus, while the
engine is driven, the operational fluid is supplied into the fluid
pressure chambers by the hydraulic pump. Thus, the control of the
relative rotational position is performed smoothly.
[0005] On the other hand, while the engine is stopped, the
hydraulic pump is not driven, and thus the operational fluid flows
out from the fluid pressure chambers by its own weight.
[0006] Therefore, the operational fluid is reserved in an oil pan,
and the temperature of the oil is low at the start of the engine.
In this state, viscosity of the operational fluid is high, and
resistance of the flow passage is large. Consequently, it is
time-consuming to supply the operational fluid to the fluid
pressure chambers via an oil passage of an oil pressure circuit.
For the reason, it is difficult to smoothly control the relative
rotational position of the driven side rotational member relative
to the driving side rotational member and properly control the
opening and closing timing of an intake valve immediately after the
start of the engine.
[0007] In JP 2003-278566A, a technology, which intends to control
the valve timing control device properly at the start of the
engine, is disclosed. A configuration which supplies the
operational fluid during engine stopping to prevent the operational
fluid from flowing out from the fluid pressure chambers of the
valve timing control device while the engine is temporary stopped.
This allows the valve timing control device to properly control the
opening and closing timings of the intake valve at the start of the
engine.
[0008] According to JP 2003-278566A, in addition to the hydraulic
pump, an extra pump is required to supply the operational fluid
during the engine stopping. Consequently, the configuration of the
valve timing control device becomes complicated, and weight of the
vehicle is increased.
[0009] A certain amount of time has elapsed since the engine
started, then the viscosity of the operational fluid becomes high
and it is not possible to supply the operational fluid to a desired
area promptly. In order to lower the viscosity of the operational
fluid, it is necessary to raise the temperature, however it needs a
certain amount of time.
[0010] The present invention has been made in view of the above
circumstances, and provides a valve timing control device which is
able to supply the high viscosity operational fluid in a short time
and perform the opening and closing timing control of the valves at
a proper timing with a simple configuration.
SUMMARY OF THE INVENTION
[0011] According to an aspect of the present invention, a valve
timing control device includes a driving side rotational member
synchronously rotating with a crankshaft of an internal combustion
engine, a driven side rotational member arranged coaxially with the
driving side rotational member and rotatable relative to the
driving side rotational member, the driven side rotational member
rotating integrally with a camshaft for opening and closing valves
for the internal combustion engine, a retarded angle chamber formed
by the driving side rotational member and the driven side
rotational member and displacing a relative rotational phase of the
driven side rotational member relative to the driving side
rotational member in a retarded angle direction, an advanced angle
chamber formed by the driving side rotational member and the driven
side rotational member and displacing the relative rotational phase
of the driven side rotational member relative to the driving side
rotational member in an advanced angle direction, a first control
valve controlling supply and discharge states of an operational
fluid between an operational fluid reservoir provided at a lower
portion of the internal combustion engine and the advanced angle
chamber and the retarded angle chamber, a supply passage supplying
the operational fluid from the operational fluid reservoir to the
first control valve, a first pump provided at the supply passage
and pumping the operational fluid in the operational fluid
reservoir to a vapor liquid separating portion, a second pump
provided at the supply passage and pumping the operation fluid in
the vapor liquid separating portion to the first control valve, a
discharge passage discharging the operational fluid from the first
change valve toward the operational fluid reservoir; and a second
control valve provided at the discharge passage and operated to
selectively switch the discharge passage between a first discharge
passage discharging the operational fluid discharged from the first
change valve to the operational fluid reservoir and a second
discharge passage flowing the operational fluid to be drawn into a
drawing portion of the first pump.
[0012] According to another aspect of the present invention, a
valve timing control device includes a driving side rotational
member synchronously rotating with a crankshaft of an internal
combustion engine, a driven side rotational member arranged
coaxially with the driving side rotational member and rotatable
relative to the driving side rotational member, the driven side
rotational member rotating integrally with a camshaft for opening
and closing valves for the internal combustion engine, a retarded
angle chamber formed by the driving side rotational member and the
driven side rotational member and displacing a relative rotational
phase of the driven side rotational member relative to the driving
side rotational member in a retarded angle direction, an advanced
angle chamber formed by the driving side rotational member and the
driven side rotational member and displacing the relative
rotational phase of the driven side rotational member relative to
the driving side rotational member in an advanced angle direction,
a first change valve controlling supply and discharge states of an
operational fluid between an operational fluid reservoir provided
at a lower portion of the internal combustion engine and the
advanced angle chamber and the retarded angle chamber, a supply
passage supplying the operational fluid from the operational fluid
reservoir to the first change valve, a pump provided at the supply
passage and supplying the operation fluid in the operational fluid
reservoir to the first change valve, a discharge passage
discharging the operational fluid from the first change valve
toward the operational fluid reservoir; and a second control valve
provided at the discharge passage and operated to selectively
switch the discharge passage between a first discharge passage
discharging the operational fluid discharged from the first change
valve to the operational fluid reservoir and a second discharge
passage flowing the operational fluid to be drawn into a drawing
portion of the first pump.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] 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:
[0014] FIG. 1 is a sectional side view illustrating an entire
configuration of a valve timing control device 1 according to the
invention;
[0015] FIG. 2 is a view illustrating the cross section taken along
a line II-II of FIG. 1 and an oil pressure circuit in detail;
[0016] FIG. 3 is a view illustrating the cross section taken along
a line III-III of FIG. 1 and the oil pressure circuit in
detail;
[0017] FIG. 4 is a view illustrating an oil pressure circuit of
another embodiment; and
[0018] FIG. 5 is a view illustrating the configuration of the valve
timing control device according to the embodiments of the
invention.
DETAILED DESCRIPTION
[0019] Embodiments of the present invention will be described below
with reference to the attached drawings. FIG. 1 is a sectional side
view illustrating an entire configuration of a valve timing control
device 1. FIG. 2 is a view illustrating a cross section taken along
a line II-II of FIG. 1 and FIG. 3 is a view illustrating a cross
section taken along the line III-III of FIG. 1.
[0020] The valve timing control device 1 can be mounted on a
vehicle provided with only an engine as an internal combustion
engine 10 as a driving means or a hybrid type vehicle provided with
a driving means having an engine and an electric motor. Thus, the
valve timing control device 1 is a device which controls an opening
and closing timing of valves 14 relative to the driving means
having at least the engine from among the above described
components (i.e. the engine and the electric motor.).
[0021] The valve timing control device 1 according to the
embodiment includes an external rotor 2 serving as a driving side
rotational member rotating synchronously with a crankshaft 9 of an
engine, and an internal rotor 3 serving as a driven side rotational
member integrally rotating with a camshaft 11 for opening and
closing valves 14 of the engine.
[0022] The internal rotor 3 is integrally assembled to a distal end
portion of the camshaft 11 serving as a rotational shaft of a cam
for controlling opening and closing of an intake valve or an
exhaust valve of the engine. The internal rotor 3 is fitted so as
to be coaxially arranged and relatively rotatable within a range of
a predetermined relative rotation relative to the external rotor 2.
A rear plate 21 is unitarily assembled to the external rotor 2 at a
side where the camshaft 11 is connected and a front plate 22 is
unitarily assembled to the external rotor 2 at an opposite side
where the camshaft 11 is connected. A timing sprocket 23 is formed
at an external periphery of the external rotor 2. A power
transmission member 12 such as a timing chain and a timing belt is
extended between the timing sprocket 23 and a gear attached to the
crankshaft 9 of the engine.
[0023] Upon rotation of the engine crankshaft 9, a rotational force
is transmitted to the timing sprocket 23 via the power transmission
member 12, the external rotor 2 rotates along a rotational
direction S shown in FIG. 2. In response to the rotation, the
internal rotor 3 rotates along the rotational direction S to rotate
the camshaft 11, and a cam provided at the camshaft 11 pushes the
intake valve or the exhaust valve down to open the valve.
[0024] As shown in FIG. 2, plural projections 24 each serving as a
shoe projected in a radially inner direction are arranged on the
external rotor 2 having intervals from each other along the
rotational direction. A fluid pressure chamber 4 defined by the
external rotor 2 and the internal rotor 3 is formed between
adjacent projections 24 of the external rotor 2. For example, four
fluid pressure chambers 4 are formed according to the embodiment of
the present invention.
[0025] A vane groove 31 is formed on an external periphery portion
of the internal rotor 3 facing each fluid pressure chamber 4. A
vane 32 for defining the fluid pressure chamber 4 into an advanced
angle chamber 41 and a retarded angle chamber 42 in a relative
rotational direction (i.e. in the direction of arrows S1, S2 of
FIG. 2) is slidably located in the vane groove 31 along a radial
direction. The vane 32 is biased radially outward by means of a
spring 33 provided at an inner radial side of the vane 32.
[0026] Volume of the advanced angle chamber 41 becomes larger by
the injection of the operational fluid, and then the relative
rotational phase of the internal rotor 3 relative to the external
rotor 2 is displaced to an advanced angle direction (arrow S1 of
FIG. 2). Volume of the retarded angle chamber 42 becomes larger by
the injection of the operational fluid, and then the relative
rotational phase of the internal rotor 3 relative to the external
rotor 2 is displaced to a retarded angle direction (arrow S2 of
FIG. 2). For the operational fluid, an operational oil such as a
lubricating oil can be used. Viscosity of the operational oil is
usually high, and resistance of the flow passage is large before
the engine starts driving, i.e. before circulating in a
predetermined passage. Temperature of the operational oil rises,
and the viscosity becomes low by circulating the predetermined
passage after the engine starts driving. At this point, the
resistance of the flow passage, which occurred when the operational
oil flows down, is lowered. Hereinafter, the operational fluid is
referred as the operational oil.
[0027] The advanced angle chamber 41 of each fluid pressure chamber
4 is in communication with an advanced angle passage 43 formed on
the internal rotor 3, the retarded angle chamber 42 is in
communication with a retarded angle passage 44 formed on the
internal rotor 3, and the advanced angle passage 43 and the
retarded angle passage 44 are connected to an oil pressure circuit
7 described below.
[0028] As illustrated in FIG. 2, out of the four advanced angle
chambers, the advanced angle passage 43 of the advanced angle
chamber 41 adjacently positioned to a lock mechanism 5 is a passage
formed along a sliding surface of the internal rotor 3 with the
external rotor 2 so that an engaging recessed portion 51 of the
lock mechanism 5 is in communication with the advanced angle
chamber 41, and the advanced angle passage 43 is in communication
with the oil pressure circuit 7 via a lock passage 55. The lock
mechanism 5 is structured between the internal rotor 3 and the
external rotor 2 so as to be able to restrict the displacement of
the relative rotational phase of the internal rotor 3 relative to
the external rotor 2 at a predetermined lock phase by a lock member
53.
[0029] The operational oil is supplied or discharged into either or
both the advanced angle chambers 41 or/and the retarded angle
chambers 42 from the oil pressure circuit 7, and thus the relative
rotational phase of the internal rotor 3 is displaced relative to
the external rotor 2 in the direction of one of the advanced angle
direction S1 and the retarded angle direction S2, or a biasing
force is generated to hold the relative rotational phase at a
arbitrary phase.
[0030] A range where the relative rotation phase of the internal
rotor 3 relative to the external rotor 2 is able to displace
corresponds to a range where the vane 32 is able to displace in the
fluid pressure chamber 4, i.e. a range positioned between the most
advanced angle phase and the most retarded angle phase.
[0031] As illustrated in FIG. 1, a torsion spring 13 is provided
between the internal rotor 3 and the front plate 22 fixed to the
external rotor 2. Both end portions of the torsion spring 13 are
held at supporting portions formed in the internal rotor 3 and the
external rotor 2 respectively. The torsion spring 13 provides a
torque which is constantly biasing the internal rotor 3 and the
external rotor 3 in the direction which the relative rotational
phase is displaced in the advanced angle direction S1.
[0032] <Oil Pressure Circuit>
Next, the configuration of the oil pressure circuit 7 is described.
(refer to FIG. 2 and FIG. 3). The oil pressure circuit 7 is
provided with a first change valve (first change valve) 74, which
controls the supply and the discharge states of the operational oil
between an operational fluid reservoir 76 provided at a lower
portion of the internal combustion engine 10 and the advanced angle
chamber and the retarded angle chamber. An oil passage 60a and an
oil passage 60b are connected to the first change valve 74. The oil
passages 60a and 60b are connected to the advanced angle passage 43
and the retarded angle passage 44 respectively. Thus, the first
change valve 74 is in communication with the fluid pressure
chambers 4.
[0033] The oil pressure circuit 7 is provided with a supply passage
61 and a discharge passage 62. The supply passage 61 supplies the
operational oil from the operational fluid reservoir 76 to the
first change valve 74, and the discharge passage 62 discharges the
operational oil from the first change valve 74 toward the
operational fluid reservoir 76.
[0034] The supply passage 61 is provided with the first pump 71 and
the second pump 72. The first pump 71 pumps the operational oil of
the operational fluid reservoir 76 to a vapor liquid separating
portion 73, and the second pump 72 supplies the operational oil
reserved in the vapor liquid separating portion 73 to the first
change valve 74. On the other hand, the discharge passage 62 is
provided with a first discharge passage 62a and a second discharge
passage 62b. The first discharge passage 62a discharges the
operational oil discharged from the first change valve 74 to the
operational fluid reservoir 76, and the second discharge passage
62b flows the operational oil, which is discharged from the first
change valve 74, into the drawing portion of the first pump 71.
Further, the discharge passage 62 is provided with a second change
valve (second control valve) 75, which selectively switches the
discharge passage between the first discharge passage 62a and the
second discharge passage 62b.
[0035] The first change valve 74 is connected with the second
change valve 75 by an oil passage 62c, and the first and second
change valves 74 and 75 are controlled by a controller 80
(controlling means).
[0036] (Hydraulic Pump)
In the embodiment, the first and second pumps 71 and 72 are
hydromechanical pumps driven by transmission of a driving force of
the crankshaft 9 of the engine.
[0037] The first pump 71 draws the operational oil reserved in the
operational fluid reservoir 76 from a drawing portion via the oil
passage 61a and also draws the operational oil from the first
change valve 74 via the second discharge passage 62b by switching
the state of the second change valve 75. Then, the first pump 71
discharges the drawn operational oil to the vapor liquid separating
portion 73 via the oil passage 61b.
[0038] The second pump 72 draws the operational oil coming from the
vapor liquid separating portion 73 via oil passage 61c from a
drawing portion to supply the operational oil to the fluid pressure
chambers 4 via the oil passage 61d, the first change valve 74, and
one of the oil passage 60a and the oil passage 60b.
[0039] (Vapor Liquid Separating Portion)
The liquid surface level of the operational oil reserved in the
operational fluid reservoir 76 moves up and down due to vibration
caused by driving of a vehicle. Therefore, a lower end of the oil
passage 61a is in either one of two states. In one state, the lower
end of the oil passage 61a reaches the liquid surface. In the other
state, the lower end of the oil passage 61a does not reach the
liquid surface. In that case, if the operational oil is drawn by
the first pump 71, air comes to be mixed with the operational oil.
If the operational oil is supplied to the fluid pressure chambers 4
being mixed with air, the lubrication property is lowered in the
fluid pressure chambers 4 to cause inconveniences. Thus, it is
necessary to separate the operational oil from the mixed air before
supplying the operational oil to the fluid pressure chambers 4.
[0040] The vapor liquid separating portion 73 is provided between
the first pump 71 and the second pump 72 and has a reservoir
chamber 73a where a certain amount of the operational oil can be
reserved. The vapor and liquid separating portion 73 has the first
communicating hole 73b and the second communicating hole 73c. The
first communicating hole 73b connects the reservoir chamber 73a
with the oil passage 61b. The second communicating hole 73c is
provided at a lower position compared to the first communicating
hole 73b and connects the reservoir chamber 73a with the oil
passage 61c.
[0041] In other words, the operational oil being mixed with air is
separated from air in the reservoir chamber 73a, and only the
operational oil is flowed out from the second communicating hole
73c where air is not mixed to the oil. Therefore, the operational
oil separated from air, is supplied to the fluid pressure chambers
4.
[0042] (The First Change Valve)
As for the first change valve 74, for example, a variable
electromagnetic spool valve, can be used. The variable
electromagnetic spool valve displaces a spool, which is slidably
disposed in a sleeve, against a spring by energization from the
controller 80 to a solenoid.
[0043] The first change valve 74 has an advanced angle port, a
retarded angle port, a supply port, and a discharge port. The
advanced angle port is in communication with the advanced angle
passage 43 and the lock passage 55, the retarded angle port is in
communication with the retarded angle passage 44, the supply port
is in communication with a flow passage positioned at a downstream
of the second pump 72, and the discharge port is in communication
with a flow passage positioned at an upstream of the second change
valve 75.
[0044] The first change valve 74 is a three position control valve
which is able to perform three mode control. One of the three modes
is advanced angle control (refer to FIG. 3) in which the advanced
angle port is communicated with the supply port and the retarded
angle port is communicated with the discharge port. The second mode
is retarded angle control in which the retarded angle port is in
communication with the supply port and the advanced angle port is
in communication with the discharge port. The other mode is hold
control (refer to FIG. 2) in which the advanced port and the
retarded port are blocked.
[0045] The first change valve 74 controls the supply or the
discharge of the operational fluid to the advanced angle chambers
41 and the engaging recessed portion 51 of the lock mechanism 5, or
the retarded angle chambers 42 by operating under the control of
the controller 80. Thus, the first change valve 74 controls the
switching between a lock state and a released state of the lock
mechanism 5 and the relative rotational phase of the internal rotor
3 relative to the external rotor 2.
[0046] (The Second Change Valve)
For the second change valve 75, as in the case of the first change
valve 74, a variable electromagnetic spool valve can be used. The
second change valve 75 has a discharge port, a drawing port and a
drain port. The discharge port is in communication with a flow
passage positioned at a downstream of the first change valve 74,
the drawing port is in communication with a flow passage positioned
at an upstream of the first pump 71, and the drain port is in
communication with the operational fluid reservoir 76.
[0047] The second change valve 75 is a two position control valve
which is able to perform two mode control. One of the modes is
drawing control (refer to FIG. 3), in which the discharge port is
in communication with the drawing port. The other mode is drain
control (refer to FIG. 2) in which the discharge port is in
communication with the drain port.
[0048] The second change valve 75 controls the supply of the
operational fluid to the fluid pressure chambers 4 via the second
discharge passage 62b, the first pump 71, the vapor liquid
separating portion 73, and the second pump 72, and also controls
the discharge of the operational fluid to the operational fluid
reservoir 76 via the first discharge passage 62a by being operating
under the control of the controller 80.
[0049] (Controller)
The controller (ECU) 80 performs the operational control of the
first change valve 74 and the second change valve 75. The
controller 80 utilizes an arithmetic processing unit. The
controller 80 controls an operation of the engine based on an
operation approving command or an operation stopping command input.
That is to say, the controller 80 put the engine into the
operational state after the operation approving command is
received. When the engine is in the operational state and the
driving operation such as an accelerating operation is preformed,
the controller 80 controls the engine in response to the driving
operation. Furthermore, the controller 80 puts the engine into the
unoperational state after the operation stopping command is
received.
[0050] The controller 80 switches the discharge passage 62 to the
second discharge passage 62b immediately after the start of the
engine and then controls the second change valve 75 to switch the
second discharge passage 62b to the first discharge passage 62a
once the predetermined condition is satisfied after the engine
starts.
[0051] (Switching the Discharge Passage by the Second Change
Valve)
When the engine is stopped, the operational oil is not supplied to
the fluid pressure chambers 4. Consequently, the operational oil
flows from the fluid pressure chambers 4 by its own weight, and
then the operational oil is reserved in the operational fluid
reservoir 76 or the vapor-liquid separating portion 73. The
temperature of the operational oil is lowered and the viscosity of
the oil is high at this point.
[0052] In this state, the resistance of the flow passage of the
operational oil is large, and thus it is time-consuming to supply
the operational oil into the fluid pressure chambers 4 via the oil
passage of the oil pressure circuit. Therefore, it is difficult to
smoothly control the relative rotational phase of the internal
rotor 3 relative to the external rotor 2 immediately after the
start of the engine and also difficult to properly control the
opening or closing timing of the intake valve. In order to avoid
the situation, the valve timing control device 1 of this embodiment
is configured so as to supply the high viscosity operational oil to
the fluid pressure chambers 4 in a short time.
[0053] After the engine starts and the operating approving command
is input to the controller 80, the first and second pumps 71 and 72
are driven. At the same time, the controller 80 controls the second
change valve 75 to switch the discharge passage 62 to the second
discharge passage 62b immediately after the start of the engine. In
other words, the first change valve 74 is put into the advanced
angle control state and the second change valve 75 is put into the
drawing control state by the commands from the controller 80 (refer
to FIG. 3). The retarded angle chambers 42, the retarded angle
passages 44, the first change valve 74, the second change valve 75
and the second discharge passage 62b come to be in communication by
driving of the first pump 1 and vacuum pressure is generated in the
inside of the above components.
[0054] Each fluid pressure chamber 4 is divided into the advanced
angle chamber 41 and the retarded angle chamber 42 by the vane 32.
However, the advanced angle chamber 41 and the retarded angle
chamber 42 are not airtightly divided by the vane 32. Hence, when
the passages ranging from the second discharge passage 62b to the
retarded chambers 42 are drawn by the first pump 71, the vacuum
pressure is generated in the advanced angle chambers 41, which is
slightly in communication with the retarded angle chambers 42. The
advanced angle chambers 41 are connected with the operational fluid
reservoir 76 via the advanced angle passage 43, the first change
valve 74, the second pump 72, the vapor liquid separating portion
73 and the first pump 71. Therefore, when the first pump 71 starts
the operation, the operational oil, which is discharged from the
second pump 72 via the first change valve 74, more easily flows
into the advanced angle chambers 41 or the retarded angle chambers
42.
[0055] That is, immediately after the start of the engine, even if
the viscosity of the operational oil is in high state, influence of
the increased resistance of the operational oil against the flow
passage can be reduced by generating the vacuum pressure in the
second discharge passage 62b when the operational oil is circulated
in the valve timing control device 1. Thus, the operational fluid
can be supplied promptly to the inside of the advanced angle
chambers 41 or the retarded angle chambers 42, and the valve timing
control device 1 is able to perform the control at an proper timing
with a simple configuration.
[0056] Once the predetermined condition is satisfied after the
engine starts, the second change valve 75 is controlled by the
controller 80 so as to switch the discharge passage 62 to the first
discharge passage 62a. At this time, the second change valve 75 is
converted from the drawing control to the drain control by the
command of the controller 80, and the operational oil is discharged
to the operational fluid reservoir 76 via the first discharge
passage 62a.
[0057] In other words, for example, the temperature of the
operational oil rises to 60-80 degrees Celsius by a warming up
operation following the start of the engine, the viscosity of the
operational oil is lowered. Consequently, the resistance of the
flow passage is lowered. At this point, the operational oil is
smoothly supplied without the control to generate the vacuum
pressure in the second discharge passage 62b by the first pump 71.
Thus, the discharge passage 62 is switched to the first discharge
passage 62a, which is usually used. In this manner, it is possible
to select an appropriate passage based on the state of the
operational oil by controlling the second change valve 75 by means
of the controller 80.
[0058] The predetermined condition may be, for example, the
temperature of at least one of the operational oil and an engine
coolant, which is preliminarily set. If the second change valve 75
is controlled based on the temperature of the operational oil to be
flowed, it is possible to perceive the viscosity of the operational
oil in the most certain way and control the second change valve 75
for switching at an appropriate timing. Alternatively, if the
control is performed based on the temperature of the coolant, it is
possible to indirectly perceive the viscosity of the operational
oil without adding any particular equipments because a thermometer
of the coolant is provided at nearly every vehicle. Therefore, it
is also possible to control the second change valve 75 for
switching at the appropriate timing.
[0059] The temperature of the operational oil is measured by an
operational oil measuring means (not shown) provided at the flow
passage where the operational oil flows down. On the other hand,
the temperature of the coolant is measured by a coolant measuring
means (not shown) provided at the flow passage where the coolant
flows down. The measuring means are configured so that at least one
result of the temperature measurements of the operational oil and
the coolant is sent to the controller 80.
[0060] The predetermined condition may be a time period which is
preliminarily set. That is, the device determines if the
temperature of the operational oil rises to lower the viscosity and
the resistance of the flow passage is lowered based on the time
period that is elapsed since the engine start. More specifically,
as the usage of the individual vehicle does not significantly vary,
for example, the ending time of the warming up operation may be
preliminary set based on an area where the vehicle is used. It is a
relatively simple means to control based upon the time period and
it is possible to switch the second change valve 75 at the
appropriate timing.
ANOTHER EMBODIMENT 1
[0061] In the aforementioned embodiment, the controller 80 controls
the second change valve 75 to switch the discharge passage 62 to
the second discharge passage 62b immediately after the start of the
engine. For instance, while the vehicle has been driven at a high
speed, the response speed of the valve timing control device 1 is
expected to be faster than that of normal speed operation. Under
the circumstances, when a predetermined time period is elapsed
since the engine started, the second change valve 75 may be
controlled so as to switch the discharge passage 62 to the second
discharge passage 62b. In this case, the predetermined time period
has elapsed since the engine started, and the temperature of the
operational oil has risen to some extent. Thus, the resistance of
the flow passage is low. Furthermore, the second discharge passage
62b is drawn by the first pump 71 so as to generate the vacuum
pressure therein. Therefore, it is possible to supply the
operational oil to the inside of the fluid pressure chambers 4
promptly.
ANOTHER EMBODIMENT 2
[0062] In the aforementioned embodiment, the configuration, which
uses the two pumps, is employed, however, the configuration may not
be limited to this way. For example, as illustrated in FIG. 4, the
configuration, which uses a pump and does not have the vapor liquid
separating portion 73, may be employed.
[0063] In other words, the pump 71, which supplies the operational
oil of the operational fluid reservoir 76 to the first change valve
74, is provided at the supply passage 61. On the other hand, the
second change valve 75 is provided at the discharge passage 62 and
operated to selectively switch the discharge passage between the
first discharge passage 62a and the second discharge passage 62b.
The first discharge passage 62a discharges the operational oil
discharged from the first change valve 74 to the operational fluid
reservoir 76, and the second discharge passage 62b flows the
operational oil discharged from the first change valve 74 to be
drawn into the drawing portion of the pump 71.
[0064] Thus, the number of the pump is decreased compared to the
aforementioned embodiment and the vapor liquid separating portion
73 is not formed. Therefore, the configuration of the oil pressure
circuit 7 can be simplified. As in the case of the aforementioned
embodiment, the pump is a hydromechanical pump which is driven by
the transmission of the driving force of the crankshaft 9 of the
engine. The other configuration is identical to that of the
aforementioned embodiment.
[0065] If the operational oil of the operational fluid reservoir 76
is drawn by the pump 71 immediately after the start of the engine,
the operational oil is circulated among the fluid pressure chambers
4, the oil passage 60b and the first change valve 74. The
operational oil is disappeared from the inside of the fluid
pressure chambers 4 when the engine is stopped, and it requires a
certain amount of time to fill the supply passage 61 and the
discharge passage 62 with the operational oil. Therefore, the
second change valve 75 is controlled so as to switch the discharge
passage 62 to the first discharge passage 62a immediately after the
start of the engine until eliminating the air existing in the
discharge passage 62.
[0066] Once the predetermined condition is satisfied after the
engine starts, the second change valve 75 is controlled so as to
switch the discharge passage 62 to the second discharge passage
62b. As described above, the passages ranging from the second
discharge passage 62b to the retarded angle chamber 42 is drawn by
the pump 71 after eliminating the air existing in the fluid
pressure chambers 4 immediately after the start of the engine.
[0067] After that, once the second predetermined condition is
satisfied since the engine starts, the second change valve 75 is
controlled so as to switch to the first discharge passage 62a. As
for the second predetermined condition, as in the case of the first
embodiment, both time and temperature are applicable.
[0068] This invention can be applied to the valve timing control
device having the first change valve controlling the supply and the
discharge states of the operational fluid among the advanced angle
chambers, the retarded angle chambers, the operational fluid
reservoir provided at the internal combustion engine 10.
[0069] The first configuration characteristic of the valve timing
control device is including a driving side rotational member
synchronously rotating with a crankshaft of an internal combustion
engine, a driven side rotational member arranged coaxially with the
driving side rotational member and rotatable relative to the
driving side rotational member, the driven side rotational member
rotating integrally with a camshaft for opening and closing valves
for the internal combustion engine, a retarded angle chamber formed
by the driving side rotational member and the driven side
rotational member and displacing a relative rotational phase of the
driven side rotational member relative to the driving side
rotational member in a retarded angle direction, an advanced angle
chamber formed by the driving side rotational member and the driven
side rotational member and displacing the relative rotational phase
of the driven side rotational member relative to the driving side
rotational member in an advanced angle direction, a first change
valve controlling supply and discharge states of an operational
fluid between an operational fluid reservoir provided at a lower
portion of the internal combustion engine and the advanced angle
chamber and the retarded angle chamber, a supply passage supplying
the operational fluid from the operational fluid reservoir to the
first change valve, a first pump provided at the supply passage and
pumping the operational fluid in the operational fluid reservoir to
a vapor liquid separating portion, a second pump provided at the
supply passage and pumping the operation fluid in the vapor liquid
separating portion to the first change valve, a discharge passage
discharging the operational fluid from the first change valve
toward the operational fluid reservoir; and a second change valve
provided at the discharge passage and operated to selectively
switch the discharge passage between a first discharge passage
discharging the operational fluid discharged from the first change
valve to the operational fluid reservoir and a second discharge
passage flowing the operational fluid to be drawn into a drawing
portion of the first pump.
[0070] According to the configuration, when the discharge passage
is switched to the second discharge passage by the second change
valve, the second discharge passage is drawn by the first pump to
generate the vacuum pressure therein. At this time, the vacuum
pressure is also generated in the advanced chambers or the retarded
chambers, which are in communication with the second discharge
passage via the first change valve. Therefore, when the first pump
starts the operation, the operational fluid discharged from the
second pump via the first change valve more easily flows into the
advanced angle chambers or the retarded angle chambers.
[0071] That is, even if the viscosity of the operational oil is
high, influence of the increased resistance of the flow passage
against the operational fluid can be reduced by generating the
vacuum pressure in the second discharge passage when the
operational oil is circulated in the valve timing control device 1.
Thus, the operational fluid can be supplied promptly to the inside
of the advanced angle chambers or the retarded angle chambers, and
the valve timing control device is able to perform the control at
the proper timing with a simple configuration.
[0072] In this configuration, only the second change valve and the
second discharge passage need to be added. Thus, the configuration
of the valve timing control device can be simplified.
[0073] The second configuration characteristic of the valve timing
control device is including the controller controlling the second
change valve to switch the discharge passage to the second
discharge passage immediately after the start of the internal
combustion engine and switch the discharge passage to the first
discharge passage once the predetermined condition is satisfied
after the engine starts.
[0074] According to the second configuration characteristic, the
control of the second change valve is performed in two steps.
Usually, the temperature of the operational fluid is low and the
viscosity is high immediately after the start of the internal
combustion engine. At this point, the second change valve is
controlled to generate the vacuum pressure in the second discharge
passage by the first pump. Thus, it is possible to supply the
operational fluid into the inside of the advanced angle chambers or
the retarded angle chambers promptly, even if the viscosity of the
operational fluid is high. On the other hand, once the
predetermined condition is satisfied after the engine starts, the
temperature of the operational fluid is risen and the viscosity
becomes low. In this case, the operational fluid is smoothly
supplied into the advanced angle chambers or the retarded angle
chambers without the control for generating the vacuum pressure in
the second discharge passage by the first pump. Consequently, the
discharge passage is switched to the first discharge passage which
is normally used.
[0075] Therefore, according to the configuration, it is possible to
select the proper passage based on the state of the operational
fluid and control the opening and closing timings of the valves
immediately after the start of the internal combustion engine.
[0076] The third characteristic of the valve timing control device
is including a driving side rotational member synchronously
rotating with a crankshaft of an internal combustion engine, a
driven side rotational member arranged coaxially with the driving
side rotational member and rotatable relative to the driving side
rotational member, the driven side rotational member rotating
integrally with a camshaft for opening and closing valves for the
internal combustion engine, a retarded angle chamber formed by the
driving side rotational member and the driven side rotational
member and displacing a relative rotational phase of the driven
side rotational member relative to the driving side rotational
member in a retarded angle direction, an advanced angle chamber
formed by the driving side rotational member and the driven side
rotational member and displacing the relative rotational phase of
the driven side rotational member relative to the driving side
rotational member in an advanced angle direction, a first change
valve controlling supply and discharge states of an operational
fluid between an operational fluid reservoir provided at a lower
portion of the internal combustion engine and the advanced angle
chambers and the retarded angle chambers, a supply passage
supplying the operational fluid from the operational fluid
reservoir to the first change valve, a pump provided at the supply
passage and supplying the operation fluid in the operational fluid
reservoir to the first change valve, a discharge passage
discharging the operational fluid from the first change valve
toward the operational fluid reservoir and a second change valve
provided at the discharge passage and operated to selectively
switch the discharge passage between a first discharge passage
discharging the operational fluid discharged from the first change
valve to the operational fluid reservoir and a second discharge
passage flowing the operational fluid to be drawn into a drawing
portion of the first pump.
[0077] According to the third configuration characteristic of the
valve timing control device, when the discharge passage is switched
to the second discharge passage by the second change valve, the
vacuum pressure is generated in the second discharge passage.
Consequently, the pump starts the operation, then the operational
fluid discharged via the first change valve flows into the advanced
angle chambers or the retarded angle chambers more easily.
[0078] That is, even if the viscosity of the operational oil is
high, influence of the increased resistance of the operational oil
against the flow passage can be reduced by generating the vacuum
pressure in the second discharge passage when the operational oil
is circulated in the valve timing control device 1. Thus, the
operational fluid can be supplied promptly to the inside of the
advanced angle chambers or the retarded angle chambers, and the
valve timing control device is able to perform the control at the
proper timing with a simple configuration.
[0079] Particularly, in the configuration, one pump is included and
the vapor liquid separating portion, which is illustrated in the
first configuration characteristic, is not provided. Only the
second change valve and the second discharge passage need to be
added. Thus, the configuration of the valve timing control device
can be simpler.
[0080] The fourth configuration characteristic of the valve timing
control device is including the controller controlling the second
change valve to switch the discharge passage to the first discharge
passage immediately after the start of the internal combustion
engine and switch the discharge passage to the second discharge
passage once the predetermined condition is satisfied after the
engine starts.
[0081] According to the fourth configuration characteristic, the
control of the second change valve is performed in two steps. The
operational fluid disappeared from the advanced angle chambers and
the retarded angle chambers during the engine stopping. Thus, the
second change valve is controlled so as to switch the discharge
passage to the first discharge passage immediately after the start
of the internal combustion engine to connect the first discharge
passage with the operational fluid reservoir. Thus, it is possible
to completely eliminate the air existing in the advanced angle
chambers and the retarded angle chambers.
[0082] Once the precondition is satisfied after the start of the
engine, the second change valve is controlled so as to switch the
discharge passage to the second discharge passage. At this point,
even if the temperature of the operational fluid is not adequately
risen and the viscosity is high, the increased resistance of the
fluid passage can be reduced by generating the vacuum pressure in
the second discharge passage. Thus it is possible to supply the
operational oil to the inside of the advanced angle chambers or the
retarded angle chambers. On the other hand, if the temperature of
the operation fluid is adequately risen and the viscosity is low,
it is possible to supply the operational fluid more promptly to
improve the response speed of the valve timing control device.
[0083] The fifth configuration characteristic of the valve timing
control device is that the predetermined condition is a temperature
of at least one of the operational fluid and the coolant of the
internal combustion engine. The temperature is preliminary set.
[0084] According to the fifth configuration characteristic, the
criterion to determine if the operational fluid is in the state
which allows the operational fluid to be promptly supplied into the
advanced chambers or the retarded chambers is the temperature of
the operational fluid. In this manner, the criterion is set to the
temperature of the operational oil, and thus it is possible to
control the second change valve 75 for switching at the appropriate
timing. Alternatively, if the criterion is set to the temperature
of the coolant used for cooling down the internal combustion
engine, then it is possible to indirectly perceive the temperature
of the operational fluid based on the increased range of the
coolant temperature.
[0085] The sixth configuration characteristic of the valve timing
control device, the predetermined condition is the time period
which is set preliminary.
[0086] According to the sixth configuration characteristic, the
valve timing control device determines if the temperature of the
operation fluid is adequately risen to lower the viscosity and the
resistance of the flow passage is reduced based on the time period
elapsed from the start of the internal combustion engine.
Therefore, it is possible to control the second change valve for
switching at the proper timing by adding a simple component such as
a timer to the configuration.
[0087] The principles, of the preferred embodiments 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 embodiment disclosed. Further, the embodiment 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 that fall within the spirit and
scope of the present invention as defined in the claims, be
embraced thereby.
* * * * *