U.S. patent number 3,623,460 [Application Number 05/015,437] was granted by the patent office on 1971-11-30 for fuel injection valve for internal combustion engines.
This patent grant is currently assigned to Robert Bosch GmbH. Invention is credited to Gerhard Haug, Iwan Komaroff, Walter Schlagmuller, Ulrich Streicher, Hans Zeller.
United States Patent |
3,623,460 |
Komaroff , et al. |
November 30, 1971 |
FUEL INJECTION VALVE FOR INTERNAL COMBUSTION ENGINES
Abstract
An injection valve which injects fuel directly into the inlet
valve for a cylinder in an internal combustion engine comprises a
piston which is reciprocable in the chamber of a cylinder member
from a neutral position to a retracted position to thereby admit
into the chamber a metered quantity of fuel, and thereupon from
neutral to an extended position to thereby inject such quantity of
fuel into the inlet valve. The piston is moved by an
electromagnetic drive which receives signals from an electronic
control circuit.
Inventors: |
Komaroff; Iwan (Ludwigsburg,
DT), Zeller; Hans (Doeffingen, DT), Haug;
Gerhard (Stuttgart, DT), Streicher; Ulrich
(Bamberg, DT), Schlagmuller; Walter (Butthard,
DT) |
Assignee: |
Robert Bosch GmbH (Stuttgart,
DT)
|
Family
ID: |
5726617 |
Appl.
No.: |
05/015,437 |
Filed: |
March 2, 1970 |
Foreign Application Priority Data
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|
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Feb 28, 1969 [DT] |
|
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P 19 10 114.5 |
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Current U.S.
Class: |
123/472;
239/585.2 |
Current CPC
Class: |
F02M
57/027 (20130101); F02M 51/04 (20130101); Y02T
10/12 (20130101); Y02T 10/123 (20130101); F02B
2275/14 (20130101) |
Current International
Class: |
F02M
51/04 (20060101); F02M 57/02 (20060101); F02M
57/00 (20060101); F02d 005/00 () |
Field of
Search: |
;123/32,32EA,32AE,139E
;239/88,89,90,533,585 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Goodridge; Laurence M.
Claims
What is claimed as new and desired to be protected by Letters
Patent is set forth in the appended claims:
1. A fuel injection valve for internal combustion engines,
particularly for direct injection of fuel into the inlet valve for
a cylinder in an internal combustion engine, comprising a cylinder
member defining a chamber and provided with a fuel admitting
opening means and fuel discharging orifice means; a piston
reciprocably received in said chamber; a device for sealing said
orifice means; connecting means for operating said device by said
piston; drive means operative to move said piston from a neutral
position in which said piston is sealing said opening means and the
device is sealing said orifice means, to a retracted second
position whereby the piston effects admission of fuel by way of
said opening means into said chamber, and from said neutral
position to an extended third position whereby the piston operates
said device to open said orifice means and expels the previously
admitted fuel by way of said orifice means from said chamber.
2. A fuel injection valve as defined in claim 1, wherein said drive
means comprises an electromagnetic drive having a movable portion
operatively connected with said piston.
3. A fuel injection valve as defined in claim 1, wherein said
device for sealing said orifice means opens said orifice means in
response to rising fuel pressure in said chamber during movement of
said piston from neutral to third position.
4. A fuel injection valve as defined in claim 1, said device having
a first portion coupled to said piston with a predetermined
clearance which is reduced to zero during movement of said piston
from neutral to third position and a second portion which exposes
said orifice means in response to such reduction of said clearance
while said piston continues to move toward said third position.
5. A fuel injection valve as defined in claim 4, wherein said
device further comprises an intermediate portion disposed between
said first and second portions thereof and wherein said orifice
means diverges in a direction away from said piston, said second
portion comprising a substantially conical head which enters and
seals said orifice means not later than when said piston effects
admission of fuel into said chamber, said piston having an internal
compartment and a bottom surface in said compartment, said first
portion of said device comprising a plunger received in said
compartment and further comprising means for biasing said plunger
toward said bottom surface, said clearance being provided between
said plunger and said bottom surface in neutral position of said
piston and while said head seals said orifice means.
6. A fuel injection valve as defined in claim 5, wherein said
piston is further provided with an axial bore connecting said
compartment with said chamber and said intermediate portion of said
device is a stem which is slidably guided in said bore.
7. A fuel injection valve as defined in claim 1, wherein said
cylinder member is provided with auxiliary opening means which is
sealed from said chamber during predetermined stages of movement of
said piston.
8. A fuel injection valve as defined in claim 1, further comprising
means for throttling the flow of fuel into said chamber by way of
said opening means.
9. A fuel injection valve as defined in claim 1, wherein said drive
means is arranged to respectively maintain said piston in said
second and third positions for first and second intervals of time
and wherein the duration of said first intervals at least equals
the duration of said second interval.
Description
BACKGROUND OF THE INVENTION
The present invention relates to internal combustion engines in
general, and more particularly to improvements in engines of the
type wherein the fuel is injected into the cylinders. Still more
particularly, the invention relates to improvements in valves which
atomize and inject metered quantities of fuel into the cylinders of
an internal combustion engine, especially to valves whose operation
is controlled by electronically regulated electromagnetic drive
means.
Recently developed electronic control circuits which regulate the
admission of fuel to the cylinders of an internal combustion engine
render it possible, in theory, to control the admission of fuel
with a high degree of precision so that the cylinders receive an
optimum mixture of fuel and oxygen under all operating conditions.
However, it was found that the presently available valves which
atomize and inject fuel are not entirely satisfactory. As a rule,
such valves are actuated by electromagnets which receive signals
from the electronic control circuit and inject fuel to the suction
manifold. The valves are opened in response to energization of
associated electromagnets and remain open for intervals whose
length is determined by the control circuit to thus insure
injection of predetermined quantities of fuel per unit of time. It
is preferred to inject atomized fuel directly into the inlet valves
for the cylinders. This brings about the advantage that the engine
operates in the same way as if the fuel were injected directly into
the cylinder chambers without, however, necessitating
pressurization of the fuel to the same extent as in engines where
the fuel is actually injected into the cylinder chambers proper.
Thus, the injection valves which direct fuel into the inlet valves
need not pressurize the fuel to the same degree as in engines where
the orifices of injection valves discharge directly into the
chambers of the corresponding cylinders.
Another advantage of engines wherein the injection valves admit
fuel into the inlet valves rather than into the cylinder chambers
proper is that the mist formed by nonevaporated minute fuel
particles is caused to enter the cylinder chambers and produces a
desirable cooling action.
All such advantages were duly recognized in the art; however, the
presently known injection valves are incapable of insuring that a
requisite amount of fuel is injected during the intervals when the
associated inlet valves for the cylinders remain open, especially
if the engine operates at a high speed so that the intervals during
which the inlet valves remain open are very short. Attempts to
overcome such drawbacks of presently known injection valves include
an increase in pressurization of fuel which, in turn, creates
additional problems without invariably insuring that a desired
quantity of fuel is injected into an inlet valve during the short
interval when the inlet valve is open.
SUMMARY OF THE INVENTION
An object of the invention is to provide a novel and improved fuel
injection valve which is constructed and assembled in such a way
that it can invariably inject a desired quantity of fuel into an
inlet valve during the intervals when the inlet valve is open.
Another object of the invention is to provide an injection valve
which can insure timely injection and atomization of fuel even if
the fuel is supplied thereto at a relatively low pressure.
A further object of the invention is to provide an injection valve
whose operation can be regulated by presently known electronic
control circuits and which can be used with equal advantage in many
types of electronically regulated internal combustion engines.
The invention is embodied in a fuel injection valve for internal
combustion engines, particularly for direct injection of fuel into
the inlet valve for a cylinder in an internal combustion engine.
The injection valve comprises a cylinder member defining a chamber
and provided with fuel admitting opening means and fuel-discharging
orifice means, a piston reciprocably received in the chamber, and
electric drive means (preferably including an electromagnetic drive
which is regulated by the electronic control circuit for the
engine) operative to move the piston from a neutral position to a
second position whereby the piston effects admission of fuel by way
of the opening means, and from the neutral position to a third
position whereby the piston expels the thus admitted fuel by way of
the orifice means.
The injection valve preferably further comprises a sealing device
which is operatively connected with the piston and seals the
orifice means when the piston dwells in the neutral or second
position as well as during movement of the piston between neutral
and second positions.
The novel features which are considered as characteristic of the
invention are set forth in particular in the appended claims. The
improved fuel injection valve itself, however, both as to its
construction and its mode of operation, together with additional
features and advantages thereof, will be best understood upon
perusal of the following detailed description of certain specific
embodiments with reference to the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic axial sectional view of a fuel injection
valve which embodies the invention;
FIG. 2 is a diagram showing a curve representing the signals which
are used to effect movements of the piston to second position in
which the piston permits entry of fuel into the cylinder
member;
FIG. 3 is a similar diagram showing a curve representing those
signals which are used to effect movements of the piston in a
direction to expel fuel from the cylinder member; and
FIG. 4 is a diagram showing the sequence of movements and duration
of dwells of the piston in neutral, second and third positions.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to FIG. 1, there is shown a fuel injection valve
which comprises a cylinder member 13 defining a cylinder chamber
13a, a piston 12 which is reciprocable in the chamber 13a, and an
electromagnetic drive 10 which serves to reciprocate the piston 12
with reference to the cylinder member between a neutral position a,
a retracted or second position b and an extended or third position
c. The movable armature 14 of the electromagnetic drive 10 is
operatively connected with the piston 12 by a rod or shaft 11. The
arrows 15 indicate those forces which are generated by the
electromagnetic drive 10 to move the piston 12 to the retracted
position b. The forces indicated by arrows 16 are applied to move
the piston 12 to the extended position c. The numeral 29 denotes an
electronic control circuit which supplies signals to the drive
10.
The piston 12 is formed with an internal compartment 12a and with
an axial bore 17 which accommodates the intermediate portion or
stem 18 of a sealing device having a conical head 19 and a plunger
21 which is accommodated in the compartment 12a and is biased
toward the bottom surface 12b of the compartment by a helical
spring 23 which reacts against an internal shoulder of the piston
12. The numeral 22 denotes a clearance (having a width eta) which
develops between the plunger 21 and bottom surface 12b when the
piston 12 dwells in the illustrated neutral position a.
The cylinder member 13 is formed with a fuel admitting opening 24
which is sealed by the peripheral surface of the plunger 12 when
the latter dwells in the neutral position a, and with a divergent
fuel discharging orifice 20 which is sealed by the head 19 when the
piston 12 assumes the neutral position a or moves between the
positions a, b or dwells in the position b. The maximum width eta
of the clearance 22 depends on the dimensions of the valve.
The operation of the valve will be described with reference to
FIGS. 2, 3 and 4. The diagram of FIG. 2 indicates the electric
signals Jd which are furnished to the drive 10 by the circuit 29
and serve to effect movement of piston 12 from the neutral position
a to the retracted position b (suction stroke of the piston). The
diagram of FIG. 3 illustrates the electric signals Js which are
transmitted to the drive 10 and serve to effect movement of the
piston 12 from the neutral position a to the extended position c
(injection stroke of the piston). The minimum duration of a signal
Jd is tl and its maximum duration is tmax. The duration ts of each
signal Js is the same; such duration is selected in such a way that
it is less than the minimum duration of opening of the associated
inlet valve 30 (FIG 1) which admits fuel into the chamber of the
corresponding cylinder in the internal combustion engine.
FIG. 4 shows a diagram which represents movement of the piston 12
between and its dwells in the positions a, b and c. When the piston
12 dwells in the retracted position b, it exposes the discharge end
of the opening 24 and permits admission of a metered quantity q of
fuel into the chamber 13a. It is assumed that the rate of fuel
admission is constant; therefore, when the piston 12 dwells in the
position b for an interval tl, it permits the chamber 13a to
receive a quantity gl of fuel. If the electronic control circuit 29
which regulates the length of signals Jd changes the length of such
signals from tl to tmax, the chamber 13a receives a quantity gmax
of fuel. The length of signals Jd is regulated in dependency on one
or more factors which influence the operation of the internal
combustion engine, such as the pressure in the intake manifold, the
pressure of atmospheric air, the position of the gas pedal, and/or
others.
The fuel which is admitted into the chamber 13a in response to
movement of the piston 12 to the retracted position b remains in
the cylinder member 13 until the piston moves to the extended
position c, i.e., until the drive 10 receives a signal Js.
When the piston 12 dwells in the neutral position a, its peripheral
surface seals the discharge end of the opening 24. The spring 23 is
stressed sufficiently to insure that the head 19 of the sealing
device seals the fuel discharging orifice 20 in neutral position of
the piston 12. Such sealing position of the head 19 is illustrated
in FIG. 1.
As stated above, the transmission of a signal Jd to the drive 10
results in movement of the piston 12 to the position b whereby the
cylinder member 13 receives a fuel quantity gl if the length of the
signal Jd equals t. After elapse of such interval, the piston 12
returns to the neutral position a under the action of the spring 23
and its peripheral surface seals the opening 24 to entrap the
quantity gl in the chamber 13a. The drive 10 gl receives a signal
Js substantially simultaneously with opening of the inlet valve 30,
and such signal causes the piston 12 to move to the extended
position c and to dwell in this position for the interval ts.
During the initial stage of movement of piston 12 from the position
a to the position c, the front end face 12c of the piston
compresses the fuel in the chamber 13a because the bottom surface
12b moves toward the plunger 21 until the width (eta) of the
clearance 22 is reduced to zero. Thus, the sealing device trails
behind the piston 12 when the latter starts to perform its working
stroke. The head 19 is lifted off its seat in the orifice 20 when
the bottom surface 12b engages and pushes the plunger 21 toward the
chamber 13a. The orifice 20 then discharges atomized fuel directly
into the open inlet valve 30. On termination of the interval ts,
the piston 12 returns to the neutral position a to thereby return
the head 19 into sealing engagement with the seat in the orifice
20. This takes place as soon as the bottom surface 12b moves away
from the plunger 21, i.e., as soon as the width of the clearance 22
exceeds zero. During return movement of the head 19 to the sealing
position of FIG. 1, the piston 12 draws air through the orifice 20
and the quantity of such air depends on the maximum width of the
clearance 22. If such clearance is substantial, the amount of air
which is sucked into the chamber 13a is small because the head 19
can reassume its sealing position at an earlier stage of movement
of the piston from the position c to the position a.
It is possible to increase the width of the clearance 22 to such an
extent that the bottom surface 12b is never in contact with the
plunger 21. The head 19 then moves to open position exclusively
under the pressure of fuel in the chamber 13a while the piston 12
moves from the position a toward the position c. The head 19 then
returns to sealing position as soon as the piston 12 leaves the
position c.
It was found that the improved fuel injection valve operates in a
most satisfactory way if the orifice 20 is immediately adjacent to
the intake end of the inlet valve 30. As stated above, the inlet
valve 30 should open not later than when the piston 12 begins to
move toward the position c and should remain open at least during
the interval ts.
The numeral 31 denotes in FIG. 1 a throttle or flow restrictor
installed in a conduit which supplies fuel to the opening 24.
The improved fuel injection valve can be provided with means for
adjusting the bias of the spring 23 and/or for regulating the width
of the clearance 22 to thus regulate the exact moment when the head
19 opens or seals the orifice 20 during axial movement of the
piston 12, i.e., during movement between the positions a and c.
An important advantage of our valve is that the entire interval
between two successive movements of the piston 12 to extended
position c is available for admission of fuel into the chamber 13a.
Such interval is long enough to insure that the chamber 13a
receives a desired quantity of fuel even if such fuel is admitted
at a relatively low pressure. Moreover, suction which is created in
the chamber 13a while the piston 12 moves to the retracted position
b promotes the inflow of fuel by way of the opening 24. Therefore,
the engine which utilizes the improved injection valves can employ
a relatively simple and inexpensive fuel pump which merely subjects
the fuel to a pressure sufficing to admit into the chamber 13a a
desired quantity of fuel which is a function of the length of the
interval (tl-1-tmax) during which the piston 12 dwells in the
retracted position b. The flow restrictor 31 in the fuel supply
conduit for the opening 24 insures that the quantity of fuel
admitted into the cylinder member 13 is independent of the pressure
in chamber 13a while the piston 12 moves toward and dwells in the
position b. Similar results can be achieved by providing the
cylinder member 13 with an auxiliary opening which is temporarily
sealed by the piston 12 and is exposed at least during a portion of
the suction stroke of piston 12 to insure that the pressure in the
chamber 13a cannot unduly influence the inflow of fuel. The control
circuit 29 shows in FIG. 1 is of the type disclosed, for example,
in the German Pat. No. 1,100,377.
Without further analysis, the foregoing will so fully reveal the
gist of the present invention that others can, by applying current
knowledge, readily adapt it for various applications without
omitting features which fairly constitute essential characteristics
of the generic and specific aspects of our contribution to the art
and, therefore, such adaptations should and are intended to be
comprehended within the meaning and range of equivalence of the
claims.
* * * * *