GB2195470A - A fuel injection pump for a motor vehicle internal combustion engine - Google Patents
A fuel injection pump for a motor vehicle internal combustion engine Download PDFInfo
- Publication number
- GB2195470A GB2195470A GB08722513A GB8722513A GB2195470A GB 2195470 A GB2195470 A GB 2195470A GB 08722513 A GB08722513 A GB 08722513A GB 8722513 A GB8722513 A GB 8722513A GB 2195470 A GB2195470 A GB 2195470A
- Authority
- GB
- United Kingdom
- Prior art keywords
- adjusting
- lever
- fuel injection
- injection pump
- governor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D1/00—Controlling fuel-injection pumps, e.g. of high pressure injection type
- F02D1/02—Controlling fuel-injection pumps, e.g. of high pressure injection type not restricted to adjustment of injection timing, e.g. varying amount of fuel delivered
- F02D1/04—Controlling fuel-injection pumps, e.g. of high pressure injection type not restricted to adjustment of injection timing, e.g. varying amount of fuel delivered by mechanical means dependent on engine speed, e.g. using centrifugal governors
- F02D1/045—Controlling fuel-injection pumps, e.g. of high pressure injection type not restricted to adjustment of injection timing, e.g. varying amount of fuel delivered by mechanical means dependent on engine speed, e.g. using centrifugal governors characterised by arrangement of springs or weights
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D1/00—Controlling fuel-injection pumps, e.g. of high pressure injection type
- F02D1/02—Controlling fuel-injection pumps, e.g. of high pressure injection type not restricted to adjustment of injection timing, e.g. varying amount of fuel delivered
- F02D1/08—Transmission of control impulse to pump control, e.g. with power drive or power assistance
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D1/00—Controlling fuel-injection pumps, e.g. of high pressure injection type
- F02D1/02—Controlling fuel-injection pumps, e.g. of high pressure injection type not restricted to adjustment of injection timing, e.g. varying amount of fuel delivered
- F02D1/08—Transmission of control impulse to pump control, e.g. with power drive or power assistance
- F02D1/10—Transmission of control impulse to pump control, e.g. with power drive or power assistance mechanical
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
- F02M41/08—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
- F02M41/10—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor
- F02M41/12—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor
- F02M41/123—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor characterised by means for varying fuel delivery or injection timing
- F02M41/125—Variably-timed valves controlling fuel passages
- F02M41/126—Variably-timed valves controlling fuel passages valves being mechanically or electrically adjustable sleeves slidably mounted on rotary piston
Abstract
A fuel injection pump for a motor vehicle internal combustion engine has an adjusting device for a fuel quantity adjusting member (16), which device has a two-arm adjusting lever (18) and a governor lever (22) which is acted upon by a governor spring (24) and a centrifugal adjuster (30). In order to guard against rapid changes in load or speed, and hence to prevent the motor vehicle jolting, a hydraulic damping device (50) is connected to the adjusting lever (18) which may be adjusted by a small amount of force and which is acted upon by an idling spring (44), which is disposed so as to be fixed to the housing. <IMAGE>
Description
SPECIFICATION
A fuel injection pump for a motor vehicle internal combustion engine
The present invention relates to a fuel injection pump for a motor vehicle internal combustion engine.
Japanese Patent Specification No. 56-206.
670, discloses a pump in which, in order to prevent sudden changes in rotational speed or load causing the motor vehicle to jerk, a damping device is associated with the adjusting device for the quantity-adjusting member.
This damping device, which comprises a hydraulic damping cylinder, is connected to the adjusting device by way of a tensioning lever which is biassed by the force of the governor spring-arrangement and against which the force of the centrifugal timer acts- in the opposite direction. by way of the adjusting lever when the internal combustion engine is in part-load or full-load operation.Since the difference between these two forces drops quadratically as a function of the rotational speed, and hence the response time of the damping device increases with increasing speed, jolting of the motor vehicle cannot be effectively prevented across the entire rotational speed range of the internal combustion engine Furthermore, an adjusting device for a quantity-adjusting member of a fuel injection pump is known from German Offenlegungsschrift No.
31 47 701, in which the governor spring arrangement and the centrifugal timer do not act on the adjusting lever, but on a lever- which acts on said adjusting lever, so that said adjusting lever can be adjusted with a small amount of force.
It would be advantageous if a fuel injection pump could be provided which enables uniform damping to be obtained throughout the entire speed range.
According to the present invention there is provided a fuel injection pump for an internal combustion engine in a motor vehicle, including a fuel quantity-adjusting member which determines the quantity of fuel to be injected, and an adjusting device which adjusting device serves as a control criterion for the rotational speed of the internal combustion engine, which actuates the quantity-adjusting member and upon which act a governor spring arrangement, a speed-dependent centrifugal adjuster and a damping device, the adjusting device comprising an adjusting lever and a governor lever having a common- fulcrum with and cooperating with said adjusting lever; wherein the governor spring arrangement and the centrifugal adjuster act on the governor lever and the damping device acts on the adjusting lever which is also acted on by said- coaxially mounted lever and actuates the adjusting member.
The fuel injection pump in accordance with
the present invention has the advantage that coupling the damping device to the adjusting
lever, which is subjected to only a-small, speed-independent adjusting force, enables
uniform damping to be obtained throughout
the entire speed range. Appropriate dimen
sioning of the damping device allows the re
sponse time to be set at the desired level.
The behaviour of the fuel quantity adjusting
device can be matched to the required magni- tudes.
Preferably, one end of the idling spring ar
rangement acts on the adjusting lever, and the
other end is suspended so as to be fixed to
the housing. This is particularly advantageous,
as it produces a separation of the forces of
the governor spring and the idling spring.
The invention is described further herein
after, by way of example only, with reference
to the accompanying drawings in which:
Fig. 1 is a section- through a simplified first embodiment of a fuel injeciton pump having
an adjusting device in accordance -with the
present invention; and
Fig. 2 is a simplified side view of a second
embodiment of an adjusting device in accor- dance with the present invention.
A pump piston 3 operates in a cylinder bore
2 in a housing 1 of a fuel injection pump and
is moved in a reciprocating and simultaneòusly rotating manner by a drive (not shown).-The
pump working chamber 4 of this pump unit is
provided with fuel from a suction chamber 7
in the housing 1 during the suction stroke the pump piston 3 by way of longitudinal
grooves 5 disposed in the outer surface of
the pump piston and by way of a passage 6
in the housing 1.During the compression
stroke of the pump piston 3, fuel is delivered
from the pump working chamber 4 into a
longitudinal passage 8 in the pump piston 3,
from where it is fed by way of a- -distributor- type longitudinal groove 10 according to the
angular position of the pump piston 3 into
one of the delivery lines 11, which are dis
posed about the periphery of the cylinder bore 2 in correspondance with the numberof cyiin- ders to be supplied in the internal combustion
engine.
An annular spool 16 is displaceably
mounted on the pump piston 3 and opens a
radial bore 17, which is connected to the
longitudinal passage 8, during the. compression
stroke of the pump piston 3, thus producing a
direct connection between the working cham
ber 4 and the suction chamber 7, such=that, from the instant of opening, none of the,re- mainder of the fuel delivered by the pump
piston 3 is fed to the delivery lines 11. In
dependence on the position of the- annular spool 16, the connection to the suction cham
ber 7 is opened at an earlier or later point
during the compression stroke of the pump
piston, and the delivery of fuel is interrupted.
The further the annular spool 16 is- moved
towards the top of the pump piston 3, the greater:the quantity of fuel delivered bythe pump piston into the delivery lines 11 and to
the injection nozzles (not shown). The position -of the annular spool 16 is ad
justed by a two-arm adjusting lever 18, also
Called a quantity lever, which is pivotable
about an axle 19 and which has a head 20 on
one of its ends which projects into a recess
-21 in the annular spool 16. For--adjusting pur
poses, the axle 19 may be displaced substan --tially in parallel -with the axis ofthe pump
piston 3.To. allow for this, the axle 19 is
disposed on an adjusting rocker - 12 which is
pivotally mounted in the housing 1 - and which
is held in a predetermined position by a pres
sure spring 13 and an adjusting screw 14.
A one-arm governor lever 22, also dalled a tensioning lever, is also pivotable about the
axle 19. This governor lever 22 is acted upon
following a certain idle travel by a governor
spring 24, one end of which is attached to a
speed-adjusting lever- 25, the- other end pass
ing through a bore 26 on -the outer end of the governor lever 22 and being provided with a
stop disc 27. An adjusting sleeve 29 of a
centrifugal adjuster 30 acts on the lever 22 in
the opposite direction to the action of the
governor spring 24. The centrifugal-adjuster 30-is driven by a transmission (not shown) in
accordance with the rotational speed of the
pump piston drive.It has a plurality of flywelghts 33, which are located in a housing =32 and which have lugs 34 which act' upon.
the lower edge of the adjusting sleeve 29
which is displaceable on an axle 35 in the
longitudinal direction. A stop 36, which is
fixed to the housing, limits the 'pivoting motion Cf the governor lever 22 in the direction of
the- centrifugal adjuster 30.
The second arm 40 of the adjusting lever
18 extends alongside the governor lever 22.
On its side fencing the governor lever 22, it
has a stop 41 which, when the fuel injection
pump is at a standstill, is -at a distance a from ,the~governor lever 22. The end of the- arm 40
forks into two parts 42,43. An idling spring
44, which is weaker than the governor spring
24, is attached to one part 42. The other end
of the idling spring 44 is attached -to an ad
justing lever 45, which is rotatably and fixably
mounted in the housing 1 and which can be
used to adjust the idling speed.
The second part 43. of the arm 40 of the
adjusting- lever 18 is connected by way- of -a
rod 57 two a damping device 50, whose task it is "io prevent rapid adjusting movements of
the adjusting lever 18. The damping device 50
has, in a cylinder 51, 9 piston 52, through
which the-rod 57 penetrates and which is held
between a head 53 on the free end of the rod
57 and a pressure spring 54 resting on the
part 43. One end of the piston 52 is subjected to the pressure ofthe fuel in the suc
tion chamber 7 and the other end is con
nected to the suction chamber 7 by way of a
throttle bore 55 and a non-return valve 56,
which is in the piston 52 and which closes
the throttle bore 55 in one direction.As a
result of the piston 52, which is held so as to
yield in one direction, and the non-return valve
56, the damping device 50 acts in one direc
tion. only, such that when the rod 57 is dis
placed in one direction the piston 52 moves rapidly, and- when it is displaced in the other
direction, the piston 52 moves slowly. In ad
dition, it is pointed out that the damping de
vice 50 described above, which acts in one
direction only, can be replaced, if required, by
a known damping device acting in two direc
tions.
The adjusting device of the above-described
fuel injection pump operates as follows:
On starting, the.adjusting device for the
control spool 16 takes up the position shown
in Fig. 1. The lever 22 abuts against the adjusting sleeve 29 of the centrifugal adjuster 30
and is loosely held by the governor spring 24
such that it is at a distance b from the stop
disc 27 and at a distance a from the stop 41
of the adjusting lever 18. The adjusting lever
18 is held by the idling spring 44 in a position
in which the control spool 16 is in its highest
position, which corresponds to the maximum
quantity of fuel being injected. Following start
ing, the adjusting sleeve 29 is displaced with
increasing engine speed, so that the lever 22
comes into abutment with the stop 41 of the
adjusting lever 18.As the speed continues to
increase, the idling spring 44 abutting against
the adjusting lever 18 begins to control the
lever movement. It counterbalances the force -generated by the centrifugal timer 30,
whereby the control spool 16 is held in a position determining the idling speed. At
speeds above the idling range, the governor
lever 22 moves through the distance b to the
stop disc 27 such that the governor lever 22
is in-abutment against the stop disc 27 of the
governor spring 24.
In order to increase the rotational speed in the part-load or full-load operation of the internal combustion engine, the governor spring 24
is tensioned by way of the speed-adjusting
lever 25, so that the governor lever 22 is
pivoted against the force of the centrifugal adjuster 30. The adjusting lever 18, which has
been jointly guided therewith, moves the control spool 16 into a position for greater quan titles of injected fuel.
In the event of a rapid change to the posi 'tion of the speed-adjusting lever 25 by the
driver or in the event of a rapid change in
load, a so-called abrupt application of load, which causes the force of the centrifugal ad juster.30 to be altered, the position of the
lever 22 is rapidly adjusted, but the position of the adjusting lever 18, which is coupled to the damping device 50, is altered after a certain time delay, so that the quantity of fuel to be injected is also adjusted after a delay.As a result of the damping device 50, which acts in one direction only, given a sudden increase in the rotational speed effected by the centrifugal adjuster 30, the adjusting lever 18 is rapidly adjusted by the governor lever 22, since the head 53 of the rod 57, which is connected to the adjusting lever 18, can lift off the piston 52 against the force of the pressure spring 54, whereby the adjusting lever 18 moves the conrol spool 16 into a position for a somewhat lower quantity of fuel to be injected. In contrast, the damping device 50, which is controlled by the throttle bore 55, acts against rapid adjustment of the adjusting lever 18 and the control spool 16 in the event of rapid tensioning of the governor spring 24 or of a rapid reduction in rotational speed.As already mentioned above, a damping device which acts in two directions enables changes in the quantity of fuel to be injected to be delayed with respect to time in the event of either an increase or a decrease in the rotational speed. As a result of the fact that the damping device 50 is coupled to the adjusting lever 18, which is subjected to small forces only, for example the idling spring 44, which is attached so as to be fixed to the housing, the response time of the damping device 50 is substantially constant throughout the entire speed range.
The embodiment of the adjusting device in
Fig. 2 is constructed and operates in substantially the same way as the one in Fig. 1. This embodiment differs from the embodiment in
Fig. 1 in that the governor spring 24, in addition to its attachment to the governor lever 22, is also resiliently coupled to the adjusting lever 18. A pin 60 is hooked into one end of the governor spring 24 and penetrates through the bore 26 in the lever 22 and through a bore 61 in the adjusting lever 18, which is aligned with said bore 26, and its head 62 holds a weak intermediate spring 64 by way of a spring abutment plate 63, the spring 64 being located between said spring abutment plate 63 and the adjusting lever 18.
The stop disc 27 for the lever 22 is also secured to the shaft of the pin 60. The intermediate spring 64 is intended to compensate for the play between the adjusting lever 18 and the lever 22.
Claims (6)
1. A fuel injection pump for an internal combustion engine in a motor vehicle, including a fuel quantity-adjusting member which determines the quantity of fuel to be injected, and an adjusting device which adjusting device serves as a control criterion for the rotational speed of the internal combustion engine, which actuates the quantity-adjusting member and upon which act a governor spring arrangement, a speed-dependent centrifugal adjuster and a damping device, the adjusting device comprising an adjusting lever and a governor lever having a common fulcrum with and cooperating with said adjusting lever, wherein the governor spring arrangement and the centrifugal adjuster act on the governor lever and the damping device acts on the adjusting lever which is also acted on by said coaxially mounted lever and actuates the adjusting member.
2. A fuel injection pump as claimed in claim 1, wherein said damping device comprises a hydraulic damping piston which is subjected to the internal pressure of the fuel injection pump and which has a throttle bore with an excesspressure valve connected downstream thereof.
3. A fuel injection pump as claimed in claim 1, wherein said damping device has a damping effect in both directions of adjustment.
4. A fuel injection pump as claimed in any of claims 1 to 3, wherein an idling spring arrangement also acts on the adjusting lever and at one end is fixed to the housing.
5. A fuel injection pump as claimed in claim 4, wherein said idling spring arrangement can be adjusted by an adjustable member.
6. A fuel injection pump as hereinbefore described with reference to and as illustrated in the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19863632539 DE3632539C2 (en) | 1986-09-25 | 1986-09-25 | Fuel injection pump for motor vehicle internal combustion engines |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8722513D0 GB8722513D0 (en) | 1987-10-28 |
| GB2195470A true GB2195470A (en) | 1988-04-07 |
| GB2195470B GB2195470B (en) | 1991-04-17 |
Family
ID=6310298
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8722513A Expired - Lifetime GB2195470B (en) | 1986-09-25 | 1987-09-24 | A fuel injection pump for a motor vehicle internal combustion engine |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP2637099B2 (en) |
| DE (1) | DE3632539C2 (en) |
| FR (1) | FR2604484B1 (en) |
| GB (1) | GB2195470B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2324335A (en) * | 1997-02-06 | 1998-10-21 | Actionform Limited | An in line fuel pump control rack damper |
| US6807940B2 (en) | 2000-11-13 | 2004-10-26 | Delphi Technologies, Inc. | Governor |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB695051A (en) * | 1950-03-21 | 1953-08-05 | Daimler Benz Ag | Improvements in automatic speed governing regulating means for internal combustion engines |
| GB1259748A (en) * | 1969-04-11 | 1972-01-12 | Kloeckner Humboldt Deutz Ag | A centrifugal speed governor for internal combustion engines |
| GB2015192A (en) * | 1977-12-20 | 1979-09-05 | Deere & Co | Fuel supply control system for an engine |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5341296B2 (en) * | 1973-05-30 | 1978-11-01 | ||
| GB2090430B (en) * | 1980-12-31 | 1984-06-13 | Lucas Industries Ltd | Governor system |
| DE3147701A1 (en) * | 1981-12-02 | 1983-06-16 | Robert Bosch Gmbh, 7000 Stuttgart | CONTROL DEVICE FOR A FUEL FLOW ADJUSTMENT MEMBER OF A FUEL INJECTION PUMP |
| JPS58107820A (en) * | 1981-12-21 | 1983-06-27 | Nippon Denso Co Ltd | Injection quantity adjusting device of fuel injection pump |
| DE3418437A1 (en) * | 1984-05-18 | 1985-11-21 | Robert Bosch Gmbh, 7000 Stuttgart | FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES |
| JPS6183458A (en) * | 1984-09-29 | 1986-04-28 | Nissan Motor Co Ltd | Injection quantity controller for fuel injection pump |
-
1986
- 1986-09-25 DE DE19863632539 patent/DE3632539C2/en not_active Expired - Fee Related
-
1987
- 1987-05-27 FR FR8707472A patent/FR2604484B1/en not_active Expired - Fee Related
- 1987-05-29 JP JP62131956A patent/JP2637099B2/en not_active Expired - Lifetime
- 1987-09-24 GB GB8722513A patent/GB2195470B/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB695051A (en) * | 1950-03-21 | 1953-08-05 | Daimler Benz Ag | Improvements in automatic speed governing regulating means for internal combustion engines |
| GB1259748A (en) * | 1969-04-11 | 1972-01-12 | Kloeckner Humboldt Deutz Ag | A centrifugal speed governor for internal combustion engines |
| GB2015192A (en) * | 1977-12-20 | 1979-09-05 | Deere & Co | Fuel supply control system for an engine |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2324335A (en) * | 1997-02-06 | 1998-10-21 | Actionform Limited | An in line fuel pump control rack damper |
| US6807940B2 (en) | 2000-11-13 | 2004-10-26 | Delphi Technologies, Inc. | Governor |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3632539C2 (en) | 1995-12-14 |
| JP2637099B2 (en) | 1997-08-06 |
| DE3632539A1 (en) | 1988-03-31 |
| FR2604484B1 (en) | 1994-02-25 |
| JPS6388229A (en) | 1988-04-19 |
| GB8722513D0 (en) | 1987-10-28 |
| GB2195470B (en) | 1991-04-17 |
| FR2604484A1 (en) | 1988-04-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4519352A (en) | Controlling device for a fuel-quantity adjusting member of a fuel injection pump | |
| US4312312A (en) | Fuel injection pump for internal combustion engines | |
| US4286558A (en) | Centrifugal rpm governor for fuel injected internal combustion engines, especially an idling and final rpm governor for diesel vehicle engines | |
| US4706627A (en) | Speed governor for injection pumps in internal combustion engines | |
| US4513715A (en) | Distributor injection pump for internal combustion engines | |
| US4887571A (en) | Speed governor for fuel injection pumps | |
| GB2195470A (en) | A fuel injection pump for a motor vehicle internal combustion engine | |
| US4615317A (en) | RPM governor for fuel injection pumps | |
| US4478195A (en) | Fuel injection pump for internal combustion engines | |
| US4590913A (en) | Fuel injection pump | |
| US4664081A (en) | Fuel injection system for diesel internal combustion engines, in particular vehicle diesel engines | |
| US4180040A (en) | Regulator for a fuel injection pump | |
| US4150650A (en) | Internal-combustion engine governor with means to prevent unnecessary changes in engine speed due to inertia or gravity | |
| GB2195472A (en) | A fuel injection pump for internal combustion engines | |
| US4649879A (en) | RPM governor for fuel injection pumps | |
| CA1172527A (en) | Resilient drive for fuel injection pump governor | |
| GB2259374A (en) | Speed governor for a fuel injection pump of an internal combustion engine | |
| US4913115A (en) | Fuel injection pump for internal combustion engines, especially diesel engines | |
| US3973542A (en) | Liquid fuel injection pumping apparatus | |
| GB1596574A (en) | Fuel injection pums | |
| US4438746A (en) | Rpm governor for a fuel injection pump | |
| US3443554A (en) | Fuel injection pump | |
| US4497295A (en) | Minimum-maximum speed governor for fuel-injected engines | |
| US5188076A (en) | Fuel injection pump for internal combustion engines | |
| US4253438A (en) | RPM Regulator for fuel injection pumps with an adaptation of the injection quantity |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19990924 |