Flow control valve

Details Flow control valve Flow control valve

1999-08-23

2001-12-04

Dolinar, Andrew M. (Department: 3747)

Internal-combustion engines

Charge forming device

Exhaust gas used with the combustible mixture

C251S129110

Reexamination Certificate

active

06325055

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a flow control valve used in devices such as exhaust gas re-circulation control devices for the purpose of reducing exhaust gas emissions of NO
x
or the like from internal combustion engines.
BACKGROUND OF THE INVENTION
FIG. 1
shows an exhaust gas re-circulation control device. In
FIG. 1
, reference numeral
1
denotes an internal combustion engine,
2
is an intake pipe allowing inflow if air to the engine,
3
is an intake manifold allowing inflow if air to each pipe branching from the intake pipe
2
,
4
is an air cleaner provided upstream of the intake pipe
2
,
5
is an injector which is provided in the intake pipe
2
and injects fuel. Air entering the intake pipe
2
through the air cleaner
4
flows into the engine
1
together with fuel supplied from the injector
5
.
6
represents a throttle valve which varies the degree of air intake into the engine
1
and
7
is a idle rotation speed control valve provided in the passage which bypasses the throttle valve
6
. The gas mixture which enters the engine
1
is ignited by an ignition plug not shown in the figure. After combustion, the exhaust gases are expelled into the atmosphere through the exhaust pipe
8
after being purified in the purification device
9
comprised by a catalytic converter.
10
is a flow control valve which is disposed in the exhaust gas re-circulation passage
17
which is connected to the inlet and outlet sides of the intake manifold
3
The flow control valve drives the stepping motor which controls the flow of exhaust gases.
11
is an electronic control unit which generates control signals to the flow control valve
10
on the basis of information received from the driving state detection means comprised of elements such as a throttle aperture sensor
12
which detects the degree of aperture of the throttle valve
6
, a pressure sensor
13
which detects the pressure in the intake pipe, a water temperature sensor
14
which detects the temperature of the engine cooling water, and the ignition device made up of the ignition coil
15
and the igniter
16
.
FIG. 2
is a front view showing the above flow control valve,
FIG. 3
is a longitudinal section view of
FIG. 2
taken along the line A—A.
21
is a valve housing having an inlet port
21
a
which communicates with the engine exhaust gas pipe
8
, an outlet port
21
b
which communicates with the engine inlet pipe
2
and a passage
21
c
between the inlet port
21
a
and the outlet port
21
b.
22
is a valve seat provided in the passage
21
c
of the valve housing
21
.
23
is a valve body which opens and closes the aperture of the valve seat
22
.
24
is a valve shaft on one end of which the valve body
23
is mounted and which displaces the valve body
23
to the open and closed position by reciprocating motion as a valve rod.
25
is a bush which acts as a bearing for the valve shaft
24
mounted in the valve housing
21
.
27
is a spring holder mounted on the other end of the valve shaft
24
which projects externally from the valve housing
21
.
28
is a bracket formed as a unit with the valve housing
21
by cast iron for example on the side from which the valve shaft
24
projects from the valve housing
21
. The bracket
28
is a cup shaped element of a fixed height which is sunken in a truncated cylindrical concave shape on the step motor
29
side.
A flange element
28
b
which mounts the stepping motor
29
is formed on the stepping motor
29
side of the bracket
28
through the holder
30
. A screw hole
28
c
which hinges the mounting screw
32
is provided in the flange
28
b.
The cross sectional size of the flange
28
b
is of a size having the minimum necessary strength to support the stepping motor
29
or is a slightly larger size (for example a size having a surface area twice that of the necessary strength.)
Furthermore in the bracket
28
, a large aperture
28
d
is formed which communicates with the lower face of the indented part
28
a
and, on the valve housing side
21
of the bracket
28
, there is a holder
26
which prevents the build-up of deposits within the vertical range of the bush
25
displaced by the valve shaft
24
.
The motor holder
30
is made from material having good thermal conductivity. A cylindrical member
35
which is suspended into the inner part of the indented part
28
a
of the bracket
28
is formed so as to cover the outside of the coil spring
52
and the spring holder
27
. A plurality of heat radiating fins
35
a
are provided on the outside face of the cylindrical member
35
.
Next the components of the stepping motor
29
will be explained.
36
is a hollow motor housing,
37
is a rotor which is supported in free rotation by an upper bearing
38
and a lower bearing
33
at its upper and lower ends. A magnet
39
is mounted on its outside periphery. The central part of the rotor
37
is hollow, displaces vertically and has a threaded section
37
a
formed on its inner face.
40
a
and
40
b
are upper and lower yokes which are mounted on the inner part of the motor housing
36
so as to face the magnet
39
of the rotor
37
and in the inner part of which are housed bobbins
41
a
and
41
b.
42
a
1
and
42
a
2
are coils wound around the bobbin
41
a,
42
b
1
and
42
b
2
are coils wound around the bobbin
41
b
and
43
is a plate magnetically separating the upper and lower yokes
40
a
and
40
b.
44
is an upper bearing seat
45
is an actuator rod which is supported in a hinged state by the threaded section
37
a
of the inner part of the rotor
37
and projects downwardly from the motor holder
30
. The tip of the actuator rod
45
displaces vertically and pushes against the valve shaft
24
.
Due to the fact that the actuator rod
45
is prevented from rotating by the bearing of the actuator rod and the motor bush
54
which has a rotation prevention function, the actuator rod displaces vertically in response to the rotation of the rotor
37
. A stopper
45
b
is provided in the actuator rod which contacts with and detaches from the stopper
37
b
of the rotor
37
and limits displacement above a fixed amount.
46
is a SPL washer for providing pre-load to the lower bearing
33
.
51
is a connector which supplies electrical pulses to each coil.
As shown in
FIG. 4
, the connector
51
comprises the terminals {circumflex over (
1
)}-{circumflex over (
6
)} which are electrically connected to the coils
42
a
1
,
42
a
2
,
42
b
1
,
42
b
2
, and the connector housing
51
a.
Transistors Tr
1
-Tr
4
are connected on the earthing line of the terminals {circumflex over (
1
)}, {circumflex over (
3
)}, {circumflex over (
4
)}, {circumflex over (
6
)}.
Terminal {circumflex over (
2
)} one end of which is connected to the coils
42
a
1
and
42
a
2
and terminal
5
one end of which is connected to coils
42
b
1
and
42
b
2
are connected to the electrical supply terminal +B through the switch SW. The connector housing
51
a
and the motor housing
36
are formed as a unit by resin.
52
is a coil spring which intercalates between the spring holder
27
and the bracket
28
. The coil spring pushes the valve shaft
24
upwardly towards the middle of the figure against through the spring holder
27
and maintains the valve body
23
in a closed state. While in a closed state, a gap is formed between the valve shaft
24
and the actuator rod
45
and the valve body
23
is maintained in an accurately closed state.
Next the operation of the flow control valve will be explained. The rotor
37
of the stepping motor
29
which acts as a motive source does not rotate continuously but only makes a single rotation. Firstly if an electrical current is applied to the top of the coils
42
a
1
and
42
a
2
in an anti-clockwise direction viewed from above, the upper face of the coils will be a north pole N, the lower face will be a south pole S and the stator will be a north pole. In the same way if a current is applied to the lower face of the coils
42
b
1
and
42
b
2
, a magnetic pole will be generated in the stator. As

Affiliated with

Also associated with

Rating

Flow control valve does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Flow control valve, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flow control valve will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2557484