Information
-
Patent Grant
-
6659086
-
Patent Number
6,659,086
-
Date Filed
Thursday, March 21, 200222 years ago
-
Date Issued
Tuesday, December 9, 200320 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 123 496
- 123 506
- 123 299
- 123 300
- 123 467
- 123 500
- 123 501
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International Classifications
-
Abstract
The fuel injection apparatus has one fuel pump for each cylinder of the engine, which pump has a pump piston, driven by the engine in a reciprocating motion, that defines a pump work chamber, which communicates via a line with a fuel injection valve, disposed on the engine separately from the fuel pump, which valve has an injection valve member, by which at least one injection opening is controlled, and which is movable in the opening direction, counter to a closing force, by the pressure generated in the pump work chamber, and at least one first electrically triggered control valve is provided, by which a communication of the pump work chamber with a relief chamber is controlled, and which is disposed near the fuel pump. A second electrically triggered control valve is provided, which is disposed near the fuel injection valve and by which the pressure prevailing in a control pressure chamber of the fuel injection valve is controlled, by which pressure the injection valve member is urged at least indirectly in the closing direction.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is directed to an improved fuel injection apparatus for internal combustion engines having a fuel pump for each engine cylinder.
2. Description of the Prior Art
One fuel injection apparatus of the type with which this invention is concerned is known from the literature, for instance from the textbook entitled
Dieselmotor
-
Management
[Diesel Engine Management], 2nd Ed., Verlag Vieweg, page 299. This known fuel injection apparatus, for each cylinder of the engine, has one fuel pump, one fuel injection valve, and one line connecting the fuel injection valve to the fuel pump. The fuel pump has a pump piston, driven in a reciprocating motion, that defines a pump work chamber. Near the fuel pump is a control valve, by which a communication of the pump work chamber with a relief chamber is controlled. The fuel injection valve has an injection valve member, by which at least one injection opening is controlled and which is movable in the opening direction counter to a closing force by means of the pressure generated in the pump work chamber by the fuel pump. By means of the control valve, the instant and duration of opening of the fuel injection valve can be controlled; the instant of opening is determined by providing that the pump work chamber is disconnected from the relief chamber by the control valve, and thus the high pressure generated by the fuel pump in the pump work chamber is operative. For closure of the fuel injection valve, the pump work chamber of the fuel pump is made to communicate with the relief chamber by the control valve, so that no further high pressure is operative in the pump work chamber, and the fuel injection valve is closed by the closing force acting on the injection valve member. The control valve is-disconnected by means of the line and is located relatively far from the fuel injection valve, so that when the communication of the pump work chamber with the relief chamber is opened by the control valve, the pressure at the fuel injection valve drops only in delayed fashion, and accordingly the fuel injection valve closes only with a delay, so that the instant and duration of opening of the fuel injection valve can be determined only imprecisely. A brief opening and closure of the fuel injection valve for a preinjection and postinjection that are chronologically offset from a main injection is thus feasible only with difficulty.
OBJECT AND SUMMARY OF THE INVENTION
The fuel injection apparatus of the invention has the advantage over the prior art that by means of a second control valve, a fast, undelayed closure of the fuel injection valve is made possible, as is necessary in particular to make a preinjection and postinjection that are chronologically offset from a main injection possible. To close the fuel injection valve, a high pressure is established by the second control valve in the pressure chamber of the fuel injection valve, and by this pressure the injection valve member is urged in the closing direction.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of preferred embodiments taken in conjunction with the drawings.
FIG. 1
shows a fuel injection apparatus for an internal combustion engine schematically in a first exemplary embodiment;
FIG. 2
shows a pressure course at injection openings of a fuel injection valve of the fuel injection apparatus in the first exemplary embodiment;
FIG. 3
shows a course of a pressure at injection openings of a fuel injection valve of the fuel injection apparatus;
FIG. 4
is a detail of a modified version of the fuel injection apparatus in the second exemplary embodiment;
FIG. 5
shows the fuel injection apparatus in a third exemplary embodiment; and
FIG. 6
shows the fuel injection apparatus in a fourth exemplary embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In
FIGS. 1
,
3
,
5
and
6
, a fuel injection apparatus for an internal combustion engine of a motor vehicle is shown. The fuel injection apparatus is preferably embodied as a so-called pump-line-nozzle system and for each cylinder of the engine has one fuel pump
10
, one fuel injection valve
12
, and one line
14
connecting the fuel injection valve
12
to the fuel pump
10
. The fuel pump
10
has a pump piston
18
, guided tightly in a cylinder
16
and driven in a reciprocating motion by a cam
20
of a camshaft of the engine. In the cylinder
16
, the pump piston
18
defines a pump work chamber
22
, in which fuel is compressed at high pressure by the pump piston
18
. By means of a low-pressure pump, not shown, for instance, fuel from a fuel tank
24
is delivered to the pump work chamber
22
.
The fuel injection valve
12
is disposed separately from the fuel pump
10
and communicates with the pump work chamber
22
via the line
14
. The fuel injection valve
12
has a valve body
26
, which may be embodied in multiple parts and in which a piston-like injection valve member
28
is guided longitudinally displaceably in a bore
30
. The valve body
26
, in its end region oriented toward the combustion chamber of the cylinder of the engine, has at least one and preferably a plurality of injection openings
32
. The injection valve member
28
, in its end region toward the combustion chamber, has a sealing face
34
, which for instance is approximately conical, and which cooperates with a valve seat
36
, embodied in the valve body
26
in its end region toward the combustion chamber; the injection openings
32
lead away from or downstream of this valve seat. In the valve body
26
, between the injection valve member
28
and the bore
30
, toward the valve seat
36
, there is an annular chamber
38
, which as a result of a radial widening of the bore
30
changes over into a pressure chamber
40
surrounding the injection valve member
28
. The injection valve member
28
has a pressure shoulder
42
In the region of the pressure chamber
40
. The end remote from the combustion chamber of the injection valve member
28
is engaged by a prestressed closing spring
44
, by which the injection valve member
28
is pressed toward the valve seat
36
. The closing spring
44
is disposed in a spring chamber
46
of the valve body
26
that adjoins the bore
30
. The spring chamber
46
is adjoined, on its end remote from the bore
30
, in the valve body
26
by a further bore
48
, in which a piston
50
that is joined to the injection valve member
28
is tightly guided. The piston
50
, with its end face remote from the injection valve member
28
, defines a control pressure chamber
52
in the valve body
26
. Embodied in the valve body
26
is a conduit
54
, into which the line
14
to the fuel pump
10
discharges and which itself discharges into the pressure chamber
40
, and from which a communication
56
branches off to the control pressure chamber
52
.
The fuel injection apparatus has a first control valve
60
, disposed near the fuel pump
10
, that can for instance be integrated with the fuel pump
10
. By means of the first control valve
60
, a communication
59
of the pump work chamber
22
with a relief chamber
24
is controlled; the relief chamber is for instance the fuel tank
24
, or some other region in which a low pressure prevails. The first control valve
60
is electrically triggerable and has an actuator
61
, which can be an electromagnet or a piezoelectric actuator and is electrically triggered and by which a valve member of the control valve
60
is movable. The first control valve
60
can be embodied as either pressure-balanced or not.
In a first exemplary embodiment of the fuel injection apparatus, shown in
FIG. 1
, the first control valve
60
is embodied as a 2/2-way valve. In a first switching position of the control valve
60
, the communication
59
of the pump work chamber
22
of the fuel pump
10
with the relief chamber
24
is opened by this valve, so that a high pressure cannot build up in the pump work chamber
22
. In a second switching position, by means of the control valve
60
the communication
59
of the pump work chamber
22
with the relief chamber
24
is broken, so that in the pump work chamber
22
, in the pumping stroke of the pump piston
18
, high pressure can build up. The fuel injection apparatus furthermore has a second control valve
64
, disposed near the fuel injection valve
12
, by means of which control valve a communication
63
of the control pressure chamber
52
of the fuel injection valve
12
with a relief chamber is controlled; the relief chamber is the fuel tank
24
or some other region where a low pressure prevails. The control valve
64
is electrically controllable and has an actuator
65
, which may be an electromagnet or a piezoelectric actuator, and which is electrically triggered and by which a valve member of the control valve
64
is movable. The second control valve
64
is embodied as a 2/2-way valve; in a first switching position, the communication
63
of the control pressure chamber
52
with the relief chamber
24
is opened by the control valve
64
, and in a second switching position the communication
63
of the control pressure chamber
52
with the relief chamber
24
is broken. The second control valve
64
is preferably embodied in pressure-balanced form. A throttle restriction
57
is disposed in the communication
56
of the control pressure chamber
52
with the conduit
54
. A throttle restriction
58
is also disposed in the communication
63
of the control pressure chamber
52
with the relief chamber
24
. The first control valve
60
, in the untriggered or in other words currentless state, is in a switching position in which the communication
59
of the pump work chamber
22
with the relief chamber
24
is open. The second control valve
64
, in the nontriggered or in other words currentless state, is in its switching position in which the communication
63
of the control pressure chamber
52
with the relief chamber
24
is open.
The function of the fuel injection apparatus in the first exemplary embodiment will now be explained. The control valves
60
,
64
are triggered by an electric control unit
68
. In the intake stroke of the pump piston
18
, the first control valve
60
is opened, so that the pump work chamber
22
communicates with the relief chamber
24
. When the injection is to begin, the first control valve
60
is closed by suitable triggering by the control unit
68
, so that the pump work chamber
22
is disconnected from the relief chamber
24
, and a high pressure builds up in it. The pressure prevailing in the pump work chamber
22
is also operative in the pressure chamber
40
, via the line
14
and the conduit
54
in the valve body
26
. The second control valve
64
is kept open by the control unit
68
, so that a high pressure cannot build up in the control pressure chamber
52
and instead this pressure is relieved to the relief chamber
24
. By means of the throttle restrictions
57
,
58
, it is attained that only a slight quantity of fuel can flow out of the conduit
54
into the relief chamber
24
. By means of the high pressure acting in the pressure chamber
40
on the pressure shoulder
42
of the injection valve member
28
, the injection valve member
28
is moved in the opening direction
29
counter to the force of the closing spring
44
, so that the injection valve member uncovers the injection openings
42
, and fuel is injected into the combustion chamber of the cylinder.
After that, the first control valve
60
is closed again by the control unit
68
, so that fuel can flow out of the pump work chamber
22
into the relief chamber
24
, and the high pressure is relieved. Accordingly, the pressure in the pressure chamber
40
of the fuel injection valve
12
drops as well, so that by the force of the closing spring
44
, the injection valve member
28
is moved with its sealing face
34
into contact with the valve seat
36
and closes the injection openings
32
, thus interrupting the injection. Because of the profile of the cam
20
that brings about the reciprocating motion of the pump piston
18
, only a relatively slight pressure builds up in the pump work chamber
22
and thus in the pressure chamber
40
of the fuel injection valve
12
during the first injection phase, which is a preinjection, and thus the preinjection occurs at a correspondingly low pressure and in an only slight quantity. In
FIG. 2
, the course of the pressure P at the injection openings
32
of the fuel injection valve
12
is shown over the time t during one complete injection cycle. The phase I represents the preinjection.
Next, the first control valve
60
is closed again by the control unit
68
, so that high pressure builds up in the pump work chamber
22
and in the pressure chamber
40
of the fuel injection valve
12
, as a function of the profile of the cam
20
. By means of the high pressure, the fuel injection valve
12
is opened again, and a fuel injection through the injection openings
32
into the combustion chamber of the cylinder ensues, with a main injection at a higher injection pressure and in a greater injection quantity than in the preceding preinjection. The course of the pressure at the injection openings
32
during the main injection is shown as phase II in FIG.
2
.
The second control valve
64
can remain open during the preinjection and during the main injection, so that the control pressure chamber
52
is in communication with the relief chamber
24
. It can also be provided that the second control valve
64
is closed after the preinjection, so that no further fuel can flow out of the control pressure chamber
52
into the relief chamber
24
, and the same pressure as in the pump work chamber
22
and in the pressure chamber
40
builds up in the control pressure chamber
52
as well. If for the main-injection the first control valve
60
is closed again, then the second control valve
64
can still be kept closed, so that in the control pressure chamber
52
, the same high pressure as in the pump work chamber
22
and in the pressure chamber
40
builds up. By means of the high pressure in the control pressure chamber
52
, a force acting in the closing direction, that is, counter to the opening direction
29
, acting on the piston
50
and thus on the injection valve member
28
is generated, so that the injection valve member
28
is kept with its sealing face
34
in contact with the valve seat
36
and closes the injection openings
32
, so that no injection occurs. The pressure in the pump work chamber
22
and in the pressure chamber
40
builds up in accordance with the profile of the cam
20
. Not until the second control valve
64
is opened and thus the high pressure in the control pressure chamber
52
is relieved to the relief chamber
24
can the fuel injection valve
12
open, as a result of the movement of the injection valve member
28
in the opening direction
29
by the high pressure prevailing in the pressure chamber
40
, counter to the force of the closing spring
44
. Thus because of the delayed opening of the second control valve
64
, the opening pressure of the fuel injection valve
12
can be raised, as is represented by dashed lines in
FIG. 2
for the main injection phase II.
For terminating the main injection, the second control valve
64
is closed, so that the control pressure chamber
52
is disconnected from the relief chamber
24
, and the high pressure of the pump work chamber
22
builds up in it. By the high pressure in the control pressure chamber
52
, the fuel injection valve
12
is closed and the fuel injection is interrupted. The first control valve
60
can either remain closed or be open. For a postinjection of fuel, the second control valve
64
is opened again, so that the control pressure chamber
52
is relieved, and the fuel injection valve
12
is opened again by the high pressure still prevailing in the pump work chamber
22
and in the pressure chamber
40
. The postinjection is shown in
FIG. 2
as injection phase III. The postinjection takes place at high pressure, which is generated by the corresponding profile of the cam
20
. The first control valve
60
is closed during the postinjection. To terminate the fuel injection, the first control valve
60
is opened, so that the pump work chamber
22
is relieved, and the fuel injection valve
12
closes by the force of the closing spring
44
. The second control valve
64
can be in either its closed or open position then.
In
FIG. 3
, the fuel injection apparatus is shown in a second exemplary embodiment, in which the layout is essentially the same as in the first exemplary embodiment and only the first control valve
160
is modified. The first control valve
160
has an electrically triggerable actuator
161
, in the form of an electromagnet or a piezoelectric actuator, by which a valve member of the control valve
160
is movable. The control valve
160
is embodied as a 2/3-way-valve and can accordingly assume three switching positions. In a first switching position, the communication
59
of the pump work chamber
22
with the relief chamber
24
is fully opened by the control valve
160
. In a second switching position, the communication
59
of the pump work chamber
22
with the relief chamber
24
is opened by the control valve
160
via a throttled passage, and in a third switching position the communication
59
of the pump work chamber
22
with the relief chamber
24
is broken by the control valve
160
. The second switching position of the control valve
160
can be achieved by providing that its valve member, as a result of the actuator
161
, executes only a partial stroke and thus opens only a smaller flow cross section than in the first switching position. The triggering of the first control valve
160
by the control unit
68
is in principle the same as is described above for the first exemplary embodiment; at the onset of the main injection, the control valve
160
is moved into its second switching position, in which the pump work chamber
22
has a throttled communication with the relief chamber
24
. By means of this throttled communication, it is attained that some of the fuel pumped by the pump piston
18
flows out into the relief chamber
24
, and as a result the pressure in the pump work chamber
22
reaches only a lesser height than when the control valve
160
is fully closed. As a result, it is attained that at the onset of the main injection, the fuel injection takes place at only a relatively slight pressure, as is illustrated in
FIG. 4
, which again shows the course of the pressure at the injection openings
32
of the fuel injection valve
12
. At a certain instant, the control unit
68
moves the first control valve
160
into its third switching position, in which the pump work chamber
22
is disconnected from the relief chamber
24
, and the full high pressure corresponding to the profile of the cam
20
is established in the pump work chamber
22
and thus at the injection openings
32
of the fuel injection valve
12
. The instant of the full pressure rise in the pump work chamber
22
is determined by the instant of closure of the first control valve
160
.
Otherwise, the triggering of the first control valve
160
and of the second control valve
64
by the control unit
68
is the same as has been described for the first exemplary embodiment, and thus the pressure course at the injection openings
32
shown in
FIG. 4
results, with the preinjection phase I, the main injection phase II with a graduated pressure buildup, and the postinjection phase III. By a delayed opening of the second control valve
64
, the opening pressure of the fuel injection valve
12
can again be increased, as is represented in
FIG. 4
by the dashed line showing the course of the main injection phase II.
In
FIG. 5
, the fuel injection apparatus in a third exemplary embodiment is shown, in which the basic layout is as in the first or second exemplary embodiment, and only the second control valve
164
has been modified. The second control valve
164
is embodied as a 2/2-way valve, but in a departure from the first and second exemplary embodiments, in the nontriggered or in other words currentless state of its actuator
165
, this control valve is in a switching position in which the communication
63
of the control pressure chamber
52
with the relief chamber
24
is broken. This is advantageous for safety reasons, in order to assure that in the event of an interruption in the electrical connection between the second control valve
164
and the control unit
68
to assure that the fuel injection valve
12
cannot open in response to the high pressure then building up in the control pressure chamber
52
.
In
FIG. 6
, the fuel injection apparatus is shown in a fourth exemplary embodiment, in which the basic layout is again the same as in the exemplary embodiments explained above, and only the disposition of the second control valve
264
is modified. The second control valve
264
is disposed in the communication
56
of the control pressure chamber
52
with the conduit
54
and is embodied as a 2/2-way valve. A throttle restriction
58
is disposed in the communication
63
of the control pressure chamber
52
with the relief chamber
24
. By means of the second control valve
264
, the communication
56
of the control pressure chamber
52
with the conduit
54
and thus with the pump work chamber
22
of the fuel pump
10
is controlled. The first control valve
160
can be a 2/2-way valve, or as shown in
FIG. 6
, it may a 2/3-way valve.
The function of the fuel injection apparatus in the fourth exemplary embodiment, to attain a pressure course of the kind shown in
FIG. 4
, will now be explained. For a preinjection in accordance with phase I of the pressure course in
FIG. 4
, the first control valve
160
is closed by the control unit
68
, so that the pump work chamber
22
is disconnected from the relief chamber
24
, and high pressure builds up in the pump work chamber
22
. The second control valve
264
is likewise closed, so that the control pressure chamber
52
is disconnected from the conduit
54
and thus from the pump work chamber
22
and is relieved to the relief chamber
24
via the communication
63
. Because of the high pressure operative in the pressure chamber
40
of the fuel injection valve
12
, the fuel injection valve
12
opens because its injection valve member
28
is moved in the opening direction
29
, counter to the force of the closing spring
44
. To terminate the preinjection, the first control valve
160
is opened, so that the pump work chamber
22
communicates with the relief chamber
24
; as a result, the pressure in the pump work chamber
22
and in the pressure chamber
40
drops such that the fuel injection valve
12
closes in response to the force of the closing spring
44
, which exceeds the pressure force exerted on the injection valve member
28
. In addition, the second control valve
264
can also be opened, so that the control pressure chamber
52
communicates with the conduit
54
and thus with the pump work chamber
22
.
For the main injection in accordance with phase II of the pressure course in
FIG. 4
, the first control valve
160
is moved by the control unit
68
into its second switching position, in which the pump work chamber
22
has the throttled communication with the relief chamber
24
, so that only a reduced pressure can build up in the pump work chamber
22
. The second control valve
264
is closed, and thus the control pressure chamber
52
is relieved to the relief chamber
24
. As a result of the pressure prevailing in the pressure chamber
40
, the fuel injection valve
12
opens, and a fuel injection at slight pressure ensues. Next, the first control valve
160
is put into its closed switching position by the control unit
68
, so that the full high pressure corresponding to the profile of the cam
20
builds up in the pump work chamber
22
. A fuel injection through the fuel injection valve
12
now takes place at high pressure.
To terminate the main injection, the second control valve
264
is opened by the control unit
68
, so that the high pressure of the pump work chamber
22
is operative in the control pressure chamber
52
, which reinforces the force of the closing spring
44
via the piston
50
, so that the injection valve member
28
is moved in the closing direction and closes the fuel injection valve
12
. For a postinjection in accordance with phase III in
FIG. 4
, the second control valve
264
is closed again by the control unit
68
, so that the control pressure chamber
52
is relieved to the relief chamber
24
, and because of the high pressure prevailing in the pressure chamber
40
the injection valve member
28
is moved in the opening direction
29
and opens the fuel injection valve
12
. The postinjection is effected at high pressure and is terminated by providing that the first control valve
160
is opened by the control unit
68
, so that the pressure in the pump work chamber
22
is relieved to the relief chamber
24
. In addition, the second control valve
264
can also be opened by the control unit
68
, thus reinforcing the closure of the fuel injection valve
12
.
The foregoing relates to preferred exemplary embodiments of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.
Claims
- 1. A fuel injection apparatus for internal combustion engines, the apparatus comprisingone fuel pump (10) for each cylinder of the engine, which pump has a pump piston (18), driven by the engine in a reciprocating motion, that defines a pump work chamber (22), which communicates via a line (14) with a fuel injection valve (12), disposed on the engine separately from the fuel pump (10), which valve has an injection valve member (28), by which at least one injection opening (32) is controlled, and which is movable in the opening direction (29), counter to a closing force, by the pressure generated in the pump work chamber (22), at least one first electrically triggered control valve (160) by which a communication (59) of the pump work chamber (22) with a relief chamber (24) is controlled, the first control valve (160) being disposed near the fuel pump (10), and a second electrically triggered control valve (64; 164; 264) which is disposed near the fuel injection valve (12) and by which the pressure prevailing in a control pressure chamber (52) of the fuel injection valve (12) is controlled, by which pressure the injection valve member (28) is urged at least indirectly in the closing direction, wherein the first control valve (160) can assume three switching positions, and wherein a first switching position the pump work chamber (22) is disconnected from the relief chamber (24); in a second switching position the pump work chamber (22) has a throttled communication with the relief chamber (24); and in a third switching position the pump work chamber (22) has a less severely throttled or an unthrottled communication with the relief chamber (24).
- 2. The fuel injection apparatus according to claim 1 wherein a communication (56) of the control pressure chamber (52) with the pump work chamber (22) is controlled by the second control valve (264).
- 3. A fuel injection apparatus for internal combustion engines, the apparatus comprisingone fuel pump (10) for each cylinder of the engine, which pump has a pump piston (18), driven by the engine in a reciprocating motion, that defines a pump work chamber (22), which communicates via a line (14) with a fuel injection valve (12), disposed on the engine separately from the fuel pump (10), which valve has an injection valve member (28), by which at least one injection opening (32) is controlled, and which is movable in the opening direction (29), counter to a closing force, by the pressure generated in the pump work chamber (22), at least one first electrically triggered control valve (60; 160) by which a communication (59) of the pump work chamber (22) with a relief chamber (24) is controlled, the first control valve (60; 160) being disposed near the fuel pump (10), and a second electrically triggered control valve (64; 164; 264) which is disposed near the fuel injection valve (12) and by which the pressure prevailing in a control pressure chamber (52) of the fuel injection valve (12) is controlled, by which pressure the injection valve member (28) is urged at least indirectly in the closing direction wherein a communication (56) of the control pressure chamber (52) with the pump work chamber (22) is controlled by the second control valve (264) and wherein the control pressure chamber (52) has a continuously open communication (63) with a relief chamber (24), and at least one throttle restriction (58) is provided in the communication (63).
- 4. The fuel injection apparatus according to claim 1 wherein a communication (63) of the control pressure chamber (52) with a relief chamber (24) is controlled by the second control valve (64; 164), and that the control pressure chamber (52) has a continuously open communication (56) with the pump work chamber (22), in which communication at least one throttle restriction (57) is provided.
- 5. The fuel injection apparatus according to claim 4 wherein, in the communication (63), controlled by the second control valve (64; 164), of the control pressure chamber (52) with the relief chamber (24), at least one throttle restriction (58) is provided.
- 6. The fuel injection apparatus according to claim 4 wherein the second control valve (164), in the non-triggered, currentless state, is in a switching position in which the control pressure chamber (52) is disconnected from the relief chamber (24).
- 7. The fuel injection apparatus according to claim 5 wherein the second control valve (164), in the non-triggered, currentless state, is in a switching position in which the control pressure chamber (52) is disconnected from the relief chamber (24).
- 8. The fuel injection apparatus according to claim 3 wherein the first control valve (160) can assume three switching positions, and wherein a first switching position the pump work chamber (22) is disconnected from the relief chamber (24); in a second switching position the pump work chamber (22) has a throttled communication with the relief chamber (24); and in a third switching position the pump work chamber (22) has a less severely throttled or an unthrottled communication with the relief chamber (24).
Priority Claims (1)
Number |
Date |
Country |
Kind |
101 13 654 |
Mar 2001 |
DE |
|
US Referenced Citations (8)