Information
-
Patent Grant
-
6405940
-
Patent Number
6,405,940
-
Date Filed
Thursday, January 25, 200123 years ago
-
Date Issued
Tuesday, June 18, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 239 88
- 239 90
- 239 91
- 239 92
- 239 93
- 239 94
- 239 95
- 239 96
- 239 5851
- 251 1291
- 251 12909
- 335 232
- 335 266
- 335 267
- 335 268
-
International Classifications
-
Abstract
A fuel injector for use in an injector arrangement including a fuel pump having a pump chamber and a spill valve arrangement including a spill valve member which is engageable with a valve seating to control communication between the pump chamber and a low pressure drain. The fuel injector further comprises a valve needle which is engageable with a valve needle seating, a control chamber arranged such that the fuel pressure therein urges the valve needle towards its seating, a control valve arrangement, including a control valve member, for controlling the fuel pressure within the chamber, and an actuator arrangement for controlling movement of the spill valve member and the control valve member. The actuator arrangement comprises a double pole actuator having a first armature which is movable with the spill valve member and a single pole actuator having a second armature which is movable with the control valve member.
Description
This invention relates to an fuel injector for use in supplying fuel, under pressure, to the cylinders of an internal combustion engine.
A known fuel injector arrangement comprises a plunger reciprocable within a bore provided in a housing to pressurize fuel located within a pump chamber defined by the bore. The pump chamber communicates with a fuel pressure actuated injector such that once the fuel pressure within the pump chamber exceeds a predetermined level, the injector opens and, thus, fuel injection commences.
In order to permit independent control of the injection pressure and the timing of injection, it is known to provide a spill valve which communicates with the pump chamber, and an injection control valve which controls the pressure applied to a control chamber defined, in part, by a surface associated with a needle of the injector to control movement of the needle. In use, the spill valve remains open during initial inward movement of the plunger. Subsequently, the spill valve is closed, further inward movement of the plunger pressurizing the fuel within the pump chamber. When injection is to commence, the injection control valve is actuated to connect the control chamber to a low pressure drain thus permitting movement of the needle away from its seating to commence fuel injection.
It has also been proposed to arrange the injection control valve such that it is biased into a position in which the control chamber communicates with the low pressure drain. Actuation of the injection control valve causes communication between the low pressure drain and the control chamber to be broken and permits fuel under high pressure to flow into the control chamber.
Conventionally, movement of the spill valve and the injection control valve is controlled by means of two separate actuators. Each actuator comprises a winding and two poles, each winding requiring separate and independent electrical connections. The electrical connections to the actuators can be difficult to accommodate within the fuel injector housing. Furthermore, the twin-poles of each actuator occupy a relatively large space. This has disadvantages in terms of size and cost.
It is an object of the present invention to provide a fuel injector which alleviates these disadvantages.
According to the present invention there is provided a fuel injector for use in an injector arrangement including a fuel pump having a pump chamber and a spill valve arrangement including a spill valve member which is engageable with a spill valve seating to control communication between the pump chamber and a low pressure drain, a valve needle which is engageable with a valve needle seating, a control chamber arranged such that the fuel pressure therein urges the valve needle towards its seating, a control valve arrangement, including a control valve member, for controlling the fuel pressure within the control chamber, and an actuator arrangement for controlling movement of the spill valve member and the control valve member, the actuator arrangement comprising a double pole actuator having a first armature which is movable with the spill valve member and a single pole actuator having a second armature which is movable with the control valve member.
The invention provides the advantage that a reduced space is required to accommodate the actuator arrangement as one of the actuators is of the single pole type.
Conveniently, the spill valve member is of relatively large diameter and the control valve member is of smaller diameter. The control valve member may be engageable with first and second control valve seatings to control communication between the pump chamber and the control chamber and between the control chamber and the low pressure drain.
Conveniently, the control valve member may be provided with resilient bias means for biasing the control valve member against the second control valve seating to close communication between the control chamber and the low pressure drain. Conveniently, the spill valve member may be provided with further resilient bias means for biasing the spill valve member away from the spill valve seating to open communication between the pump chamber and the low pressure drain.
The first and further resilient bias means may take the form of first and second compression springs. Alternatively, the first and further resilient bias means may be provided by a single compression spring.
Although the single pole actuator only provides a relatively weak force, as the control valve member is only of relatively small diameter the force provided by the single pole actuator is sufficient to move the control valve member away from the second control valve seating against the first control valve seating. The double pole actuator provides a larger force which permits a spill valve member of relatively large diameter to be employed. As the spill valve member can have a relatively large diameter, a relatively high rate of flow of fuel is permitted past the spill valve seating when the spill valve is open.
The actuator arrangement is conveniently housed within an actuator housing. The actuator housing may be provided with a drilling which forms part of a supply passage for fuel which communicates with the pump chamber. It is possible for the supply passage to be formed, in part, within the actuator housing as the actuator arrangement occupies a reduced space within the actuator housing.
Conveniently, the actuator arrangement comprises first and second windings associated with first and second actuators respectively. The first and second windings may be arranged such that they share a common electrical connection. Thus, fewer electrical connections to the fuel injector are required.
According to another aspect of the present invention, there is provided an actuator arrangement for use in an injector arrangement including a fuel pump having a pump chamber, a spill valve arrangement including a spill valve member which is engageable with a spill valve seating to control communication between the pump chamber and a low pressure drain and a control valve arrangement, including a control valve member, for controlling the fuel pressure within a control chamber, the actuator arrangement comprising a double pole actuator having a first armature which is movable with the spill valve member and a single pole actuator having a second armature which is movable with the control valve member.
The invention will now be described, by way of example only, with reference to the accompanying drawings in which:
FIG. 1
shows a sectional view of a fuel injector in accordance with an embodiment of the invention;
FIG. 2
shows a sectional view of the fuel injector in
FIG. 1
approximately along line A—A;
FIG. 3
is a sectional view of the actuator arrangement forming part of the fuel injector in
FIGS. 1 and 2
; and
FIG. 4
is a sectional view similar to that in
FIG. 3
, of an alternative embodiment of the invention.
Referring to
FIGS. 1 and 2
, the fuel injector comprises a nozzle body
10
which is provided with a bore within which a valve needle
12
is reciprocable. The bore includes an enlarged diameter region which defines an annular chamber
14
for fuel, fuel being supplied to the annular chamber
14
and the bore through a supply passage
15
defined by drillings formed in the nozzle body
10
and in various fuel injector housing parts, to be described hereinafter. The valve needle
12
is engageable with a seating to control fuel delivery through one or more outlet openings (not shown) provided in the nozzle body
10
. The housing parts and the nozzle body
10
are secured within a cap nut
16
.
The injector further includes a pump unit comprising a plunger member
17
which is reciprocable within a plunger bore
18
provided in a housing
25
under the action of a cam arrangement, only a tappet member
19
of which is shown, a return spring
20
being provided in order to withdraw the plunger member
17
from the plunger bore
18
. The housing
25
abuts, at its lowermost end, a further housing
26
which is provided with a recess which defines, together with the plunger bore
18
, a pump chamber
21
for fuel. The pump chamber
21
communicates with a spill valve arrangement, referred to generally as
24
, by means of the supply passage
15
and a passage
23
provided in an additional housing
27
in abutment with the further housing
26
. The supply passage
15
also permits fuel to flow from the pump chamber
21
to the annular chamber
14
and the bore provided in the nozzle body
10
, fuel within the bore acting against appropriately orientated thrust surfaces (not shown) of the valve needle
12
to urge the needle
12
away from its seating provided in the nozzle body
10
.
As can be seen most clearly in
FIG. 3
, the spill valve arrangement
24
includes a spill valve member
22
which is slidable within a further bore
28
provided in the further housing
27
, the further bore
28
opening into a chamber
29
which is connected to a low pressure drain or reservoir. The spill valve member
22
is engageable with a seating
28
a
defined by the further bore
28
to control communication between the pump chamber
21
and the chamber
29
and, hence, between the pump chamber
21
and the low pressure drain. Movement of the spill valve member
22
is controlled by means of a first actuator forming part of an electromagnetic actuator arrangement, referred to generally as
34
. The actuator arrangement
34
includes first and second actuators having first and second actuator windings
36
,
46
respectively. The first actuator winding
36
is associated with two poles
37
a
,
37
b
and the second actuator winding
46
is associated with a single pole
48
, the poles
37
a
,
37
b
,
48
and the windings
36
,
46
being located within an actuator housing
38
. The windings
36
,
46
are spaced apart vertically by an annular bridging region
39
.
The actuator arrangement
34
further comprises first and second armatures
40
,
44
. The first armature
40
is connected to the valve member
22
such that the spill valve member
22
is movable with the first armature
40
, the first armature
40
being movable under the influence of a magnetic field generated by supplying a current to the first winding
36
. The second armature
44
is associated with an injection control valve arrangement, as will be described hereinafter, the second armature
44
being moveable under the influence of a magnetic field generated by supplying a current to the second winding
46
. The actuator windings
36
,
46
are supplied with current from an external control unit
47
by means of electrical connectors
49
a
,
49
b
respectively.
The spill valve member
22
is engageable with a seating
28
a
defined by part of the further bore
28
such that, when the spill valve member
22
engages the seating
28
a
, communication between the pump chamber
21
and the low pressure drain is not permitted. A first spring
43
is located so as to bias the spill valve member
22
towards a position in which the spill valve member
22
is lifted away from its seating
28
a
, energization of the winding
36
causing the first armature
40
and the valve member
22
to move against the force due to the first spring
43
, the spill valve member
22
thereby moving into engagement with the seating
28
a
to break communication between the pump chamber
21
and the low pressure drain.
The actuator housing
38
abuts, at its end remote from the additional housing
27
, a second further housing
41
for an injection control valve arrangement. The injection control valve arrangement includes a control valve member
42
which is slidable within a through bore
50
provided in the second housing
41
under the control of the second actuator, as described previously. The control valve member
42
is connected to the second armature
44
and is movable therewith between first and second seated positions, a first position in which the control valve member
42
engages a first valve seating
52
a
defined by the through bore
50
and a second position in which the control valve member
42
engages a second valve seating
52
b
defined by the upper end face of a distance piece
54
in abutment with the second further housing
41
.
The distance piece
54
abuts, at its end remote from the second further housing
41
, a still further housing
56
which is provided with a bore including a region of enlarged diameter, the distance piece
54
including a projection
54
a
which extends within the enlarged diameter bore region and defines, together with the enlarged diameter bore region, a spring chamber within which a second compression spring
58
is housed. The projection
54
a
forming part of the distance piece
54
is also provided with a blind bore within which a piston member
60
is slidable, the piston member
60
including an enlarged diameter region
60
a
which is connected to the upper end of the valve needle
12
such that movement of the piston member
60
within the through bore
50
is transmitted to the valve needle
12
. The end region
60
a
of the piston member
60
abuts the second spring
58
, the second spring
58
serving to bias the piston member
60
and the valve needle
12
in a downwards direction such that the valve needle
12
is urged against its seating.
The upper end face of the piston member
60
and the blind end of the bore provided in the distance piece
54
together define a control chamber
62
for fuel.
The control chamber
62
communicates with a passage
63
provided in the distance piece
54
, the passage
63
communicating, at its other end, with a passage
64
provided in the second further housing
41
which communicates with the supply passage
15
. The passage
64
communicates, intermittently, with an annular chamber
51
defined by an enlarged region of the through bore
50
, the chamber
51
communicating, intermittently, with a passage
68
provided in the distance piece
54
in communication with the low pressure drain. The control valve member
42
is engageable with the first and second valve seatings
52
a
,
52
b
respectively to control communication between the control chamber
62
and the supply passage
15
and between the control chamber
62
and the low pressure drain.
An additional spring
70
is located so as to bias the control valve member
42
towards a position in which the valve member
42
is seated against the second valve seating
52
b
such that communication between the supply passage
15
and the control chamber
62
is permitted. Thus, in use, with the winding
46
de-energized and with the valve member
42
seated against the second valve seating
52
b
, fuel in the supply passage
15
is able to flow past the first valve seating
52
a
into the control chamber
62
, and communication between the control chamber
62
and the low pressure drain is broken. During this stage of operation, fuel pressure within the control chamber
62
is therefore substantially equal to that within the supply passage
15
. The effective areas of the piston member
60
and the valve needle thrust surfaces are chosen to ensure that, in such circumstances, the force acting on the valve needle
12
due to the fuel pressure within the control chamber
62
and due to the action of the spring
58
is sufficient to urge the valve needle
12
into engagement with its seating. In such circumstances, fuel injection through the outlet openings does not take place.
When the second winding
46
is energized, the second armature
44
is moved towards the single pole
48
and the control valve member
42
is moved away from the second valve seating
52
b
, against the force due to the second spring
70
, into engagement with the first valve seating
52
a
. Under these circumstances, fuel in the supply passage
15
is unable to flow past the first valve seating
52
a
into the control chamber
62
and the control chamber
62
communicates with the low pressure drain. As a result, fuel pressure within the control chamber
62
decreases. It will be appreciated that, in such circumstances, the force acting on the valve needle
12
urging the valve needle
12
into engagement with its seating is decreased. The effective areas of the piston member
60
and the valve needle thrust surfaces are chosen to ensure that, in such circumstances, the valve needle
12
is urged away from its seating to commence fuel injection through the outlet openings.
When the second winding
46
is de-energized, the control valve member
42
returns to a position in which it seats against the second valve seating
52
b
. Under these circumstances, communication between the supply passage
15
and the control chamber
62
is re-established, and the control chamber
62
communicates with the supply passage
15
. Fuel pressure within the control chamber
62
is therefore increased, the effective area of the thrust surfaces provided on the valve needle
12
and the effective area of the piston member
60
exposed to fuel pressure within the control chamber
62
being such that, under these circumstances, the downward force applied to the valve needle
12
is sufficient to move the valve needle
12
towards its seating such that fuel delivery through the outlet openings is terminated.
In use, with the pump chamber
21
charged with fuel, and starting from a position in which the plunger member
17
is in its outermost position within the plunger bore
18
and with the first and second actuator windings
36
,
46
de-energized, the spill valve member
22
is biased away from the seating
28
a
by the spring
43
such that the pump chamber
21
communicates with the low pressure drain. Additionally, the control valve member
42
is in engagement with the second valve seating
52
b
such that the control chamber
62
communicates with the supply passage
15
. In such circumstances, the valve needle
12
engages its seating under the action of the spring
58
and fuel injection does not take place, as described previously.
From this position, the plunger member
17
commences inward movement into the plunger bore
18
under the action of the cam arrangement, such movement resulting in fuel being displaced from the pump chamber
21
, past the spill valve seating
28
a
to the low pressure drain. When it is determined that pressurization of the fuel within the pump chamber
21
should commence, firstly the first actuator winding
36
for the spill valve member
22
is energized, resulting in movement of the spill valve member
22
against the seating
28
a
to break communication between the pump chamber
21
and the low pressure reservoir. It will be appreciated that continued inward movement of the plunger
17
within the plunger bore
18
therefore results in the pressure of fuel within the pump chamber
21
, and the supply passage
15
, increasing. Thus, relatively high pressure fuel is supplied through the supply passage
15
to the annular chamber
14
and the bore provided in the nozzle body
10
and the pressure of fuel applied to the thrust surfaces of the valve needle
12
is increased. As the control valve member
42
is seated against the second valve seating
52
b
, communication between the control chamber
62
and the supply passage
15
ensures that a sufficiently high force is applied to the piston member
60
and the valve needle
12
due to fuel pressure within the control chamber
62
which, combined with the spring force due to the spring
58
, maintains engagement between the valve needle
12
and its seating. Thus, fuel injection does not take place during this stage of operation.
When fuel pressurization within the pump chamber
21
has increased to a sufficiently high level, and fuel injection is to be commenced, the actuator winding
46
is energized to move the armature
44
towards the single pole
48
. The control valve member
42
therefore moves away from the second valve seating
52
b
, against the action of the spring
70
, into engagement with the first valve seating
52
a
. Such movement of the control valve member
42
breaks communication between the control chamber
62
and the supply passage
15
and instead permits communication between the control chamber
62
and the low pressure drain. The pressure within the control chamber
62
is therefore reduced which results in a reduction in the force urging the valve needle
12
into engagement with its seating. A point will be reached at which the force applied to the thrust surfaces of the valve needle
12
is sufficient to overcome the action of the spring
58
and the reduced fuel pressure within the control chamber
62
. The valve needle
12
then lifts away from its seating to permit fuel to flow past the valve needle seating provided in the nozzle body
10
and through the outlet openings to commence fuel injection.
In order to terminate fuel injection, the first actuator winding
36
is de-energized such that the first armature
40
moves away from the poles
37
a
,
37
b
, causing the spill valve member
22
to lift away from the seating
28
a
. Fuel within the pump chamber
21
is therefore able to flow to the low pressure drain causing fuel pressure within the supply passage
15
and the bore provided in the nozzle body
10
to be reduced. A point will be reached when the force due to the spring
58
is sufficient to overcome the reduced fuel pressure acting on the thrust surfaces of the valve needle
12
such that the valve needle
12
returns to its seated position. In such circumstances, fuel delivery through the outlet openings ceases.
Alternatively, fuel injection may be terminated by de-energizing the second actuator winding
46
such that the second armature
44
is moved away from the single pole
48
causing the control valve member
42
to move away from the first valve seating
52
a
into engagement with the second valve seating
52
b
. This re-establishes communication between the supply passage
15
and the control chamber
62
. The force applied to the piston member
60
and the valve needle
12
due to fuel pressure within the control chamber
62
, combined with the force due to the spring
58
, is sufficient to overcome the fuel pressure acting on the thrust surfaces of the valve needle
12
and the valve needle
12
is therefore returned against its seating to cease fuel injection. At or after termination of injection, the first actuator winding
36
is de-energized and the spill valve member
22
moves away from the seating
28
a
under the action of the spring
43
, in which position the pump chamber
21
communicates with the low pressure drain causing fuel pressure within the pump chamber
21
to be reduced. Continued inward movement of the plunger member
17
within the plunger bore
18
results in further fuel being displaced past the spill valve seating
28
a
to the low pressure drain.
The seating
28
a
with which the spill valve member
22
is engageable has a relatively large diameter such that, during the filling phase of the injection cycle, a relatively large volume of fuel is able to flow into the pump chamber
21
. The spill valve member
22
is also therefore of relatively large diameter and a relatively large force is required to urge the spill valve member
22
against the seating
28
a
to close communication between the pump chamber
21
and the low pressure drain. This relatively large force is achieved by employing the two poles
37
a
,
37
b
in combination with the first winding
36
. However the control valve member
42
need only be of relatively small diameter compared to the diameter of the spill valve member
22
, as only a relatively low rate of flow of fuel to and from the control chamber
62
is required. Thus, the control valve member
42
also has a relatively small diameter and only a relatively weak force is required to move the control valve member
42
against the first seating
52
a
. This smaller force can be achieved using the second winding
46
in combination with a single pole
48
having a relatively small armature
44
associated therewith. By using a single pole
48
, in place of a double pole, in the actuator for the control valve member
42
, a reduced space is required to accommodate the actuator arrangement
34
whilst ensuring a sufficiently high force can be achieved to move the control valve member
42
against the first seating
52
a
. As the actuator arrangement
34
occupies a reduced space within the actuator housing
38
, the supply passage
15
can be formed, in part, within the housing
38
.
Furthermore, when the actuator winding
36
is energized, to cause movement of the spill valve member
22
towards the seating
28
a
, flux is able to pass through the bridging region
39
between the first and second windings
36
,
46
. Similarly, when the second actuator winding
46
is energized, to move the second armature
44
and the control valve member
42
against the first seating
52
a
, flux is able to pass through the bridging region
39
between the first and second windings
36
,
46
. By winding both the first and second windings
36
,
46
in such a manner that the flux flow in the first and second windings
36
,
46
flows in the same direction, only a small amount of net flux passes through the bridging region
39
. Thus, the bridging region
39
of the actuator arrangement need only be of relatively small size.
The actuator arrangement provides the further advantage that, due to the close proximity of the first and second windings
36
,
46
, the windings
36
,
46
may share a common electrical connection, thereby reducing the total number of electrical connections required to the fuel injector.
As shown in
FIG. 4
, in an alternative embodiment of the invention, the first and additional springs
43
,
70
may be replaced by a single spring
72
arranged to apply appropriate biasing forces to both the control valve member
42
and the spill valve member
22
. Additionally, it will be appreciated that the first, second and additional compression springs
43
,
58
,
70
may be replaced with any resilient bias means to provide the necessary biasing forces.
In the embodiment shown in
FIGS. 1
to
3
, it can be seen that the spill valve member
22
is secured to the first armature
40
by means of a screw which extends through a bore provided in the spill valve member
22
. Additionally, it can be seen that the control valve member
42
is secured to the second armature
44
by means of a screw arrangement. In an alternative embodiment of the invention either the spill valve member
22
, the control valve member
42
, or both members, may be secured to their respective armatures
40
,
44
by means of welding.
The spill valve member
22
and the control valve member
42
may be arranged such that, when the winding
36
is de-energized, the spill valve member
22
adopts a position in which communication between the pump chamber
21
and the low pressure drain is closed, and when the second winding
46
is de-energized, the control valve member
42
adopts a position in which communication between the control chamber
62
and the supply passage
15
is closed. It will also be appreciated that the spill and injection control valve arrangements may be of a different form to those described hereinbefore.
Claims
- 1. A fuel injector for use in an injector arrangement including a fuel pump having a pump chamber and a spill valve arrangement, the spill valve arrangement including a spill valve member which is engageable with a spill valve seating to control communication between the pump chamber and a low pressure drain and a valve needle which is engageable with a valve needle seating, a control chamber arranged such that the fuel pressure therein urges the valve needle towards its seating, a control valve arrangement, including a control valve member, for controlling the fuel pressure within the control chamber, and an actuator arrangement for controlling movement of the spill valve member and the control valve member, the actuator arrangement comprising a double pole actuator having a first armature which is movable with the spill valve member and a single pole actuator having a second armature which is movable with the control valve member.
- 2. A fuel injector as claimed in claim 1, wherein the spill valve member has a relatively large diameter compared with the diameter of the control valve member.
- 3. A fuel injector as claimed in claim 2, wherein the control valve member is engageable with first and second control valve seatings to control communication between the pump chamber and the control chamber and between the control chamber and the low pressure drain respectively.
- 4. A fuel injector as claimed in claim 3, the control valve member is provided with first resilient bias means for biasing the control valve member against the second control valve seating to close communication between the control chamber and the low pressure drain.
- 5. A fuel injector as claimed in claim 4, wherein the spill valve member is provided with second resilient bias means for biasing the spill valve member away from the spill valve seating to open communication between the pump chamber and the low pressure drain.
- 6. A fuel injector as claimed in claim 5, wherein the first and second resilient bias means take the form of first and second compression springs respectively.
- 7. A fuel injector as claimed in claim 5, wherein the first and second resilient bias means take the form of a single compression spring arranged to apply biasing forces to both the control valve member and the spill valve member.
- 8. A fuel injector as claimed in claim 1, wherein the actuator arrangement is housed within an actuator housing, the actuator housing being provided with a drilling which forms part of a supply passage for fuel in communication with the pump chamber.
- 9. A fuel injector as claimed in claim 1, wherein the actuator arrangement comprises first and second windings associated with first and second actuators respectively.
- 10. A fuel injector as claimed in claim 9, wherein the first and second windings are arranged such that they share a common electrical connection to permit current to be supplied thereto.
- 11. An actuator arrangement for use in an injector arrangement including a fuel pump having a pump chamber, a spill valve arrangement including a spill valve member which is engageable with a spill valve seating to control communication between the pump chamber and a low pressure drain and a control valve arrangement, including a control valve member, for controlling the fuel pressure within a control chamber, the actuator arrangement comprising a double pole actuator having a first armature which is movable with the spill valve member and a single pole actuator having a second armature which is movable with the control valve member.
- 12. An actuator arrangement as claimed in claim 11, further comprising first resilient bias means arranged to bias the control valve member against the second control valve seating to close communication between the control chamber and the low pressure drain.
- 13. An actuator arrangement as claimed in claim 12, further comprising second resilient bias means for biasing the spill valve member away from the spill valve seating to open communication between the pump chamber and the low pressure drain.
- 14. An actuator arrangement as claimed in claim 13, wherein the first and second resilient bias means take the form of a single compression spring arranged to apply biasing forces to both the control valve member and the spill valve member.
Priority Claims (1)
Number |
Date |
Country |
Kind |
0001766 |
Jan 2000 |
GB |
|
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
6113014 |
Coldren et al. |
Sep 2000 |
A |
6260768 |
Timms |
Jul 2001 |
B1 |
6267306 |
Phillips |
Jul 2001 |
B1 |
6321999 |
Male et al. |
Nov 2001 |
B1 |