JPH0346664B2 - - Google Patents

Abstract

1. Fuel injection device for internal combustion machines, in particular for diesel engines, having, for each working cylinder, one mechanically driven pump piston (14a-14d; 14a'-14d') of an injection pump (12a-12d) supplied by a feed pump (33) with fuel under supply pressure, having, for each working cylinder, a control spool valve (24; 24') operable by the control pressure of a control fuel source (32) common to all the injection pumps, which control spool valve is inserted in a transfer duct (22) continually connected with the pump working space (18) and closes this duct for the initiation of the beginning of injection and opens it again for the termination of injection, and having a control device (48; 48'; 48") by means of which the control pressure can be switched via control lines (29) to the pressure spaces (28) of the control spool valves (24; 24'), characterised by the following features : a) the control fuel source (32) is formed by the feed pump (33) designed for a control pressure (ps ) increased by a multiple relative to the supply pressure (pv ) of the injection pumps (12a to 12d) and by a first pressure limiting valve (35) limiting the control pressure (ps ) in a control pressure line (31) which can be connected to the control lines (29) ; b) a second pressure limiting valve (37), which determines the supply pressure (pv ) occurring in the filling lines (21) separated from the control lines (29), is connected downstream of the first pressure limiting valve (35) ; c) the control device consists of a valve arrangement (36; 48; 48'; 48") determining in common for all the injection pumps (12a to 12d) the beginning and the duration of the period during which the pressure spaces (28) of the control spool valve (24; 24') are subjected to pressure and of a distributor device (43; 53) separate from this valve arrangement, by means of which distributor device one of the control lines (29) leading to the pressure spaces (28) of the control spool valves (24; 24') can be connected at a time, in synchronism with the injections, to the control pressure line (31) ; d) the control pressure (ps ) necessary for operating the control spool valve (24; 24') and to which one of the pressure spaces (28) at a time is subjected via the distributor device (43; 53) is built up by the valve arrangement (36; 48; 48'; 48") blocking the drainage of the control fuel from the control pressure line (31) into a low pressure line (19) and is released again to the low pressure line (19) for the return stroke of the control spool valve (24; 24').

Description

DETAILED DESCRIPTION OF THE INVENTION The industrial field of application of the invention is fuel injection devices for internal combustion engines. The invention thus provides mechanically driven pump pistons of the injection pumps, in each case one per working cylinder, which are supplied with fuel at supply pressure by a conveying pump, and one in each case a control common to all injection pumps. a control slide operable by the control pressure of the fuel source at least against the force of a return spring, the control slide being inserted into an overflow conduit which is permanently connected to the pump working chamber; , this overflow conduit is closed for the start of the injection and reopened for the end of the injection, and further comprises a control device by which a control pressure can be switched via the control conduit to the pressure chamber of the control slider. The present invention relates to a fuel injection system for certain types of internal combustion engines. The control slider determines the effective delivery stroke of the injection pump and thus the fuel injection quantity by blocking backflow from the pump working chamber, and when the control slider opens the overflow conduit to allow injection pressure to escape, the injection ends.

A prior art fuel injection device of this type is described in US Pat. No. 3,486,493.
In this case, the fuel supply pressure acts on both end faces of the control slide, and a return spring additionally acts on one end face. When starting injection, the supply pressure acting on one end face is released, and the control slider is adapted to release the supply pressure acting on the other end face and the return spring acting on one end face. It is only moved by the difference in force between the Furthermore, although it is the force of the return spring that ends the injection, the force of the return spring cannot be increased arbitrarily in relation to the supply pressure in this case. Therefore, this fuel injection device is not suitable for use in high-speed rotating engines. Furthermore, in this known fuel injection device, the control pressure line is also the filling line, so that the control effect is influenced.

Furthermore, a fuel injection system of the type described above is also described in US Pat. No. 3,465,737. In this case the control slider serves as a control pump and is operated by the control pressure of a separate injection pump which is driven simultaneously with the pump nozzle; A known injection regulator for transmitting the drive torque is integrated into the drive unit. Therefore, the overall cost of this fuel injection system is extremely high.

Therefore, the problems to be solved by the present invention are as follows:
It is an object of the present invention to provide a fuel injection device of compact construction that can be used in high-speed diesel engines at low cost without using mechanical control parts for individual injection pumps.

The means of the invention for solving this problem, as set out in claim 1, consists in a fuel injection device of the type described above, in which the controlled fuel source has a pressure many times higher than the supply pressure of the injection pump. formed by a conveying pump configured to produce a high control pressure and a first pressure control valve limiting said control pressure in a control pressure conduit connectable to a plurality of control conduits; , behind the first pressure limiting valve;
A second pressure limiting valve is connected which determines the supply pressure in the filling conduit separated from the control conduit, and the control device determines the starting point and duration of the pressure load in the pressure chamber of the control slide common to all injection pumps. It is formed by a period-defining valve arrangement and, separate from this valve arrangement, a distribution arrangement, by means of which, during the injection period, in each case one of the control lines leading to the pressure chamber of the control slide is The control pressure, which can be connected to a control pressure line and which is supplied to each one of the pressure chambers via a distribution device and which is necessary for the operation of the control slide, causes the discharge of control fuel from the control pressure line into the low-pressure line. The problem lies in the fact that the flow is caused by the valve arrangement which prevents the flow and is then allowed to escape again towards the low pressure conduit due to the return stroke of the control slide. It is further provided according to the invention that the filling conduit is connected to a supply conduit common to all injection pumps and under supply pressure, the supply conduit being connected to a supply conduit common to all injection pumps, the supply conduit being able to control the flow of fuel which is discharged from the control pressure conduit via a valve arrangement. The pump working chamber can be connected to the filling conduit by means of an overflow conduit, which serves as a low-pressure conduit for the pump and is controlled by a control point of the control slider.

In the embodiment of the invention, the control conduit is separated from the filling conduit, so that a sufficiently high control pressure can be generated by means of the conveying pump. No additional control pumps requiring separate drives are required. The supply pressure is established by a pressure control valve. By adjusting the control pressure to 30-80 bar and the supply pressure to, for example, 6 bar, very fast and precise fuel injection can be achieved. Furthermore, the pressure relief shocks that occur during the switching operation of the control slides and thus the switching movements of these control slides are damped, and the overflow conduit at the same time serves to fill the pump work chamber.

The fuel injection device described in claim 1 can be further improved by the means described in claim 2 and subsequent claims. For example, according to claim 2, a metering pump is used as the conveying pump, which can supply the injected fuel quantity as well as the control fuel quantity and can generate the required control pressure.

The embodiment according to claim 3 further simplifies the line connection and replaces a corresponding part of the filling channel by the channel of the control slide.

According to claim 4, the throttle channel connecting the pressure chamber of the control slide with its spring chamber is provided in such a way that the control slide always remains in its starting position in the non-actuated state and is therefore unaffected by leakage flows. do. On the other hand, according to the embodiment of claim 5, the fuel flowing out at high pressure during pressure relief from the pump working chamber reaches directly into the spring chamber of the control slider and, if necessary, controls the control slider. It does not interfere with exercise.

According to claim 6, it is achieved that the injection start point and the injection quantity are electrically controlled by a single magnetic valve arrangement, and the extremely short switching times are achieved in accordance with claim 7. This is accomplished by an embodiment.

According to the embodiments of claims 8 to 10, the magnetic valves are combined in various forms; 3 port 2 so inserted
The use of a position valve makes it possible to clearly separate the control pressure and the supply pressure, thus ensuring a rapid stroke movement of the control slide. According to the embodiment of claim 9, a two-port, two-position valve with an extremely simple structure can be used, and simple piping becomes possible.

The embodiment according to claim 11 ensures a fast operation of the magnetic valve controlling the injection start point or injection end point in each case, so that no injection takes place in the absence of flow, increasing safety. It will be done.

A fuel injection device of the structure described in the preamble of claim 1, comprising a central rotary distributor serving as a distribution device,
This is of the type that is driven synchronously with the injection pump and is adapted to sequentially create and interrupt connections between the individual control lines and the control pressure line during the injection cycle in order to operate the control slider. In this case, the necessary distribution function is achieved by the means described in the latter part of claim 12. Since this rotary distributor only needs to perform a distribution function, its accuracy does not need to be very high.

The fuel injection device described in the first generic part of claim 1 is disclosed in the first mentioned U.S. Pat.
3,486,493, which has a central valve arrangement with a rotary distributor, the valve arrangement being adapted to determine the operating period of the control slider, the patent By means of the measures specified in the second part of claim 13, a significantly simpler type of piping and operation than in the state of the art is obtained.

In a fuel injection device with a central valve device with a rotary distributor according to claims 14 and 15, it is possible to operate only for changing the conveyance amount and changing the injection starting point. The possible dosing slide does not rotate together with the drive, so that it can be easily actuated by known electrical or mechanical adjustment elements. A particular advantage of this arrangement is that there is a precise separation of the adjustment element for changing the injection start point and the mechanically or electrically actuable adjustment element for controlling the conveyance amount.

In the embodiment of claims 16 and 17, the control pressure is supplied to the pressure chambers to be supplied with the control pressure in each case by means of a distribution device, which is formed by a control point on each pump piston. A forced connection of the conduit is possible in a simple manner and the length of the control conduit can be kept very short, thereby reducing the dead space of the control conduit and eliminating the drive of the distribution device. .

In the following, the structure of the present invention will be specifically explained with reference to the embodiments shown in the drawings.

In the fuel injection device shown in FIG. 1, four mechanically driven pump nozzles are indicated at 10a to 10d, and these pump nozzles generally correspond to drive cams 11a to 1 of the camshaft.
Injection pumps 12a to 12d each driven by 1d and configured as a piston pump;
It consists of an injection nozzle 13 that is combined with this and configured as a pressure-controlled injection valve. As the injection nozzle, it is possible to use any known injection valve which is controlled by the fuel pressure and is designed as a valve that opens outwardly or inwardly, depending on the needs of the engine. Code 14a, 14
The pump pistons, designated b, 14c and 14d, are moved against the plunger spring 15 by the drive cam 11a.
11d through the roller plunger 16 into the pump working chamber 18 formed by part of the cylinder bore 17 of the pump pistons 14a to 14d. These pump working chambers 18 are filled with fuel via a filling conduit 21 which is connected to a supply conduit 19 under a supply pressure P _V common to all pump nozzles 10a to 10d. The filling conduit 21 is
It can also be considered as an extension of the overflow conduit 22 connected to the pump work chamber 18 . In the embodiment shown, a separate filling conduit is provided in the pump work chamber 18.
Since it is not open inward, the overflow conduit 22 can also be considered as part of the filling conduit 21. At the connection between each overflow conduit 22 and the filling conduit 21 there is inserted a control slide 24 which can be operated against the force of a return spring 23 and which, in the pump nozzle 10a, is used for starting the injection. in a position to close the overflow conduit 22, whereas the other pump nozzle 10b
~10d is in the starting position for connecting the pump working chamber 18 to the filling conduit 21 and thus to the supply conduit 19, which serves as a low-pressure conduit. To simplify the filling of the conduits, the filling conduits 21 each open into a spring chamber 25 of the control slide 24, which contains a return spring 23;
A channel 26 formed by a surface or a groove in the section 24a of the control slide 24 is permanently connected to a control point 27 of the control slide 24, which is designed as a ring groove. pump nozzle 1
If the control slide 24 is in the starting position shown at 0b-10d, the control point 27 opens the connection from the filling conduit 21 to the overflow conduit 22, and in the first pump nozzle 10a this connection is closed. It has been cut off.

At its end facing away from the return spring 23, each control slide 24 delimits a pressure chamber 28, which itself is connected via a control conduit 29 to a control pressure conduit 31 common to all pump nozzles. It is connected to the.

The control pressure conduit 31 is under the control pressure P _S of the control fuel source 32 when the pressure of the fuel delivered from the tank 34 into the control pressure conduit 31 by the transfer pump 33 is determined by the first pressure limiting valve 35. . This prevents the control fuel in the control pressure conduit 31 from draining into the low pressure conduit, where it is under significantly lower pressure.
This is the case when it is prevented by In the illustrated embodiment, the supply conduit 19 serves as a low-pressure conduit and is under a supply pressure P _V . A second pressure limiting valve 37 is connected behind the first pressure limiting valve 35 to control this supply pressure _PV .

The controlled fuel source 32 is therefore formed by a conveying pump 33, in particular designed as a metering pump, and a first pressure limiting valve 35, which can be controlled if the return path is interrupted. The control pressure P _S prevailing in the pressure conduit is many times greater than the supply pressure P _V prevailing in the supply conduit 19 and the filling conduit 21 . Advantageous values are P _V =6 bar and P _S =30
Occurs at ~80 bar.

The central valve arrangement 36 for all pump nozzles 10a-10d is a rotary distributor 38.
, which is simultaneously driven by a camshaft 11 in synchronization with the injection pumps 12a to 12d, is vertically movable to change the conveyance amount, and is capable of moving vertically to its drive device to change the injection starting point. It is relatively rotatable. As can be seen in FIGS. 1 and 1a, the rotating rotary distributor 38 is provided with four control surfaces 41 on its outer surface.
In other words, the rotary distributors 38 each have one control surface 4 per controlled control conduit 29.
1. The valve arrangement 36 is inserted into a conduit 42 connecting the control pressure conduit 31 to the supply conduit 19 which serves as a low pressure conduit, in this case the conduit 4 permanently connected to the control pressure conduit 31.
The second control opening 42a is the rotary distributor 3.
The other control opening 42b, which is controlled by the control surface 41 of 8 and which leads to the low pressure conduit 19, is controlled by the control surface 41 of
Rotating distributor 3 partitioned by
It is permanently connected to the notch 40 of 8. Closing one control opening 42a of the control surface 41 creates a control pressure P _S in the control pressure conduit 31 which is limited by the first pressure limiting valve 35 and
As shown, a ring groove 43 and a control conduit 29 in the pump piston 14a serve as a distribution device.
and is guided into the pressure chamber 28 of the first pump nozzle 10a. FIG. 1 shows the first pump nozzle 10a.
Indicates the injection start position for In other words, the fuel in the pump work chamber 18 is prevented from draining into the low-pressure conduit 19 by the control slide 24, which cuts off the overflow conduit 22. If the pump piston 14a performs a further downward stroke, the fuel compressed in the pump working chamber 18 is injected via the injection nozzle 13 into the associated engine cylinder. Remaining pump nozzles 10b that are not operated
10d, the associated drive cams 11b to 11
When d is at the bottom dead center position or the top dead center position, the pressure chamber 28 of the control slider 24 is discharged from the control pressure conduit 31.
The connection to the associated pump piston 14b-14
The ring groove 43 of d is out of position and is cut off. Pump pistons 14a to 14d
The distribution device formed by four ring grooves 43 and the central valve device 36 are connected to the pump nozzle 1.
A control device is formed to control the conveyance start point and conveyance end point of 0a to 10d.

As the rotary distributor 38 rotates further in the clockwise direction from the position shown in FIG. Therefore, the pressure in the control pressure conduit 31 is increased by the pressure in the supply conduit 19.
, the notch 4 of the rotary distributor 38
0, through control opening 42b and conduit 42. The pressure in the control pressure line 31 is thereby reduced to the supply pressure P _V and is still connected to the control pressure line 31 via the annular groove 43 and the control line 29 of the first pump nozzle 10a. The pressure is reduced in the pressure chamber 28 and the return spring 23 is able to move the control slide 24 into its starting position. In this case, the pump working chamber 18 includes an overflow conduit 22, a control slide 2
4 control points 27 , a passage 26 , a spring chamber 25 and a filling conduit 21 are connected to the supply conduit 19 . As a result, the pressure in the pump working chamber 18 decreases, injection ends, and only the reference pressure corresponding to the supply pressure _PV is maintained in the pump working chamber 18.
Until the end of the remaining stroke of the pump piston 14a, excess fuel is forced out of the pump working chamber 18 into the supply conduit 19, which during the subsequent suction stroke is transferred to the filling conduit 21 and the overflow conduit. It is again filled with fuel via 22. This filling is the third
pump nozzle 10c and fourth pump nozzle 1
It ends when the pump piston 14a reaches its bottom dead center position again, like the pump pistons 14c and 14d at 0d.

The drive cams 11a to 11d move the pump pistons 14a to 14 at the bottom dead center position and the top dead center position.
d is configured to pause for a long time, so that when one of the control slides 24 is operated, another control slider is not affected. It is the ring groove 4 of the pump pistons 14a to 14d in the bottom dead center position as well as in the top dead center position.
3 breaks the connection from the pressure chamber 28 via the control conduit 29 to the common control pressure conduit 31.

In the illustrated embodiment, individual pump nozzles 10a~
10d is directly actuated by drive cams 11a to 11d, which are connected to a camshaft 11, which is shown in chain lines and is formed by an overhead engine camshaft, in order to thereby produce a high injection pressure. The required stiffness of the drive is guaranteed. Of course, the pump pistons 14a to 14d can also be driven by drive cams 11a to 11d via swing arms known per se (not shown). Advantageously, the rotary distributor 38 is also driven by the same camshaft 11, and the conveying pump is also driven by the camshaft 11, as indicated by the dashed line at the conveying pump 33, so that the entire fuel injection system is A spatially advantageous arrangement results.

In the alternative embodiments described below with respect to Figures 2 to 4, identical or equivalent parts are given the same reference numerals, and structurally modified parts are given the numerals with a dash. New parts are given new numbers.

In the second embodiment shown in FIG. 2, the pump nozzles 10a-10d are constructed in the same way as in the first embodiment of FIG. 1, and the controlled fuel source 32 operates in the same manner. In this example, four drive cams 11a-11d are shown, also connected via a camshaft 11, with the same length of control conduit 2 for each pump nozzle 10a-10d.
9 is a pump piston 14 serving as a dispensing device;
It can be connected to the control pressure conduit 31 by ring grooves 43 a to 14d. However, the valve arrangement in this case is a magnet valve arrangement 48, which consists of two magnet valves 46 and 47 and can be considered as part of the control arrangement, by means of which the magnet valves 46 and 47 are position, the flow of control fuel from the control pressure conduit 31 to the supply conduit 19 or the low pressure conduit which is under the supply pressure P _V is interrupted. This allows the control pressure conduit 31
A control pressure P _S prevails in the pressure chamber 28 of the first pump nozzle 10a. That is, the drive cam 11
a the first pump nozzle 10 until the ring groove 43 connects the associated control conduit 29 to the control pressure conduit 31 and the control slide 24 is moved to the position shown in which it cuts off the overflow conduit 22.
This is because the pump piston 14 of a has already been moved. At the same time, the control conduits 29 of the other pump nozzles 10b-10d, which are driven by the drive cams 11b-11d and are in their top dead center position or bottom dead center position, are not under the control pressure, depending on the respective position of the associated ring groove 43. and is disconnected from the control pressure conduit 31 under control pressure. The magnetic valve device is the second
As can be seen from the simple illustration in the figure, it consists of two magnetic valves 46 and 47 hydraulically connected in parallel, and by appropriately crossing the control signals of these magnetic valves, only one Extremely short control times can be achieved which cannot be achieved with a single magnet valve.

The first magnet valve 46 is constructed as a two-port, two-position valve and is shown in FIG. The connection from pressure conduit 31 to supply conduit 19 is severed. The second solenoid valve 47 is configured as a 3-port, 2-position valve, and in the unenergized first switching position shown in FIG.
One section 31 of the control pressure conduit 31 leading to
a is connected to the other part 31 b which is connected to a controlled fuel source 32 . This second
The magnet valve 47 connects the portion 31a of the control pressure conduit 31 to the supply conduit 1 by energizing the electromagnet.
9 to its second switching position. Before starting the next injection process, the first magnet valve 46 returns to its first switching position by de-energizing the electromagnet and returns to its second switching position.
The magnet valve 47 is again brought into the illustrated first switching position by de-energizing the electromagnet.

FIG. 2a shows a variation of the control slider used in all embodiments and is designated 24'. This control slider 2
4' has a throttle guide hole 51 formed substantially along its longitudinal axis, and this throttle guide hole is connected to the pressure chamber 2.
8, a spring chamber 25 containing a return spring 23;
is connected to the pressure chamber 28 via the control line 29 and the distribution device 43 is disconnected.
Leakage fuel reaching the spring chamber 25 can flow into the spring chamber 25, but at such a narrow level that it does not interfere with the operation of the control slide 24' when the pressure chamber 28 is placed under the control pressure P _S. It is formed. The throttle conduit 51 as a whole can be configured as a throttle, but the axially extending portion of the channel may be made somewhat larger in diameter and only the short section designated by reference numeral 51a in FIG. 2a may be configured as a flow restrictor. It is advantageous to form the Figures 1 and 2
Instead of the control slide 24, which is also shown and used in FIG. 3 and will be explained later, the control slide 24' in FIG. A control point (ring groove) 27' is provided, which is sealed against the spring chamber 25, by means of which the overflow conduit 22 can be connected to a separate relief conduit 52. This relief conduit 52 may lead directly to the tank 34 and be under atmospheric pressure, or it may open at a suitable point into the filling conduit 21 or into the supply conduit 19 and open into the spring chamber 22.
5 direct pressure load and thus control slider 2
4' or 24 may be avoided.

In the third embodiment shown in FIG. 3, pump pistons 14a' to 14a' of pump nozzles 10a' to 10d'
14d' represents the drive cams 11a to 11a in FIGS. 1 and 2.
Drive cams 11a'~ whose shape is different from 11d.
11d' and serving as a distribution device is a rotary distributor 53 driven synchronously with the pump nozzles 10a' to 10d', which is also connected directly or indirectly to the camshaft 11. The outer surface 54 of this rotary distributor 53 is provided with a control opening 55 which is permanently connected to the control pressure conduit 31, the width B of which measured in the circumferential direction corresponds to the rotational speed occurring in practice. Taking this into consideration, the operating period of the control slider 24 is selected to be as long as possible. The control opening 55 is a horizontal hole 56 and a vertical hole 57 in the rotary distributor 53.
are permanently connected to the control pressure conduit 31 via the individual control conduits 29 when the rotary distributor 53 performs a rotational movement in the clockwise direction to control the pump nozzles 10a'-10d'. are successively connected to the control pressure conduit 31 by control openings 55 in cycles of injection. Portion 31a of control pressure conduit 31 leading to distribution device 53 and control fuel source 32
The portion 31b of this conduit 31 is supplied with fuel from
The solenoid valve arrangement inserted into the control pressure line 31 between the solenoid valves 46' and 47, designated 48' in FIG. ' of the control pressure conduit 31 which is permanently connected to the distribution device 53 by means of these magnet valves.
1a can be connected alternately to the other part 31b of the control pressure conduit 31, which is connected to the control fuel source 32, or to the low pressure conduit or supply conduit 19. In FIG. 3, the first magnet valve 46' operated to initiate injection is connected to the control pressure conduit 3.
1 into the low pressure conduit 19 but from the controlled fuel source 32 to the rotary distributor 5.
3 and is shown in a switched position allowing controlled fuel flow to the second magnet valve 47'.
is already in this switching position, and in order to terminate the injection the second magnet valve 47' is brought into a switching position in which it releases the control pressure P _S from the section 31a of the control pressure conduit 31 leading to the rotary distributor 53. Can be switched. In this switching position a connection to the supply line 19 is created.
There is a supply pressure P _V in the supply conduit 19 which is significantly lower than the control pressure P _S ;
It is controlled by a pressure limiting valve 37 as already explained in connection with FIG.

FIG. 4 shows a simple piping magnetic valve system 48'' which can be used in place of the magnetic valve system 48 or 48' of FIGS.
It consists of two almost identical magnetic valves 46'' and 47'' which are configured as position valves. Both magnetic valves 46'' and 47'' are inserted into conduits 42' and 42'' connecting the control pressure conduit 31 to the supply conduit 19.The magnetic valves shown in FIGS. The first magnet valve 4 corresponds to the switching position of the
6'' is in its second switching position, in which the electromagnet is energized and thus breaks the connection from the control pressure conduit 31 to the low pressure conduit 19, whereas the second magnet valve 47'' is not energized. is already in its first switching position, which breaks this connection. As can be seen in FIG. 4, the control pressure conduit 31 is connected directly to the control fuel source 32 and the supply conduit 19.
branches from between the two pressure limiting valves 35 and 37. In order to improve the operation of the magnetic valve arrangement 48'', a restriction 59 is inserted in the control pressure conduit 31 in front of the conduits 42' and 42'' which create the connection to the supply conduit 19, as shown in dotted lines. You can leave it there. This diaphragm 59 must be configured as follows. That is, upon connection of the control pressure conduit 31 to the supply conduit 19 controlled by the second magnet valve 47'', a pressure drop to the supply pressure P _V which enables a return stroke of the control slider 24 occurs in the control pressure conduit. 31, such that a control pressure P _S is rapidly built up in the control pressure conduit 31 if the drainage is interrupted.

Both magnet valves 46 and 47 are shown in FIG. 2 in their switched positions to cut off the discharge from control pressure conduit 31, and magnet valves 46' and 46', as described in connection with FIGS. 3 and 4, 47' or 4
6'' and 47'' can be seen from the diagram in FIG.

On the vertical axis are both magnet valves 46 and 47 or 4
The "closed" and "open" positions of 6' and 47' or 46" and 47" are taken, time t is taken on the horizontal axis, and two curves a and b showing these relationships are taken. are drawn with their heights slightly shifted from each other. The solid curve a is the first magnet valve 46, 4
6', 46'', and the dashed curve b is for the second magnet valves 47, 47', 47''. As can be seen from curve b, at t ₁ the second
magnet valves 47, 47', 47'' are already closed, and at t ₂ the first magnet valves 46, 46', 4
6″ is switched from its open position to its closed position,
Injection, denoted by t _E , is started. The injection ends when, at turning point t ₃ , the second magnet valve 47, 47', 47'' switches to the open position. Immediately thereafter, at time t ₄ , the first magnet valve 46, 46', 46'' switches again. It can be switched to its open position. Therefore, before the closing movement of both magnet valves which takes place at times t ₁ and t ₂ , both magnet valves are open and the pressure in the control pressure line 31 is released into the low pressure line 19 . By switching two magnet valves in this way, the use of pressure-balanced commercial magnet valves requiring a minimum switching time is also due to extremely short switching times, i.e. reduced to zero. be able to. The switching times, which depend solely on the stroke of the valve member, are shown by the slope sections of curves a, b, and the electrical switching pulses for the associated electromagnets are shown by curves c and d. . As can be seen from curves c and d, the first solenoid valve 46, 46', 46'' is connected for the start of injection just before t ₂ and at a freely definable point between t ₃ and t ₄ . As the dashed curve d shows, the second magnet valve 47, 47', 47'' is connected at t ₃ to end the injection and before t ₂ , e.g. ₁ or again at t ₅ as shown by the dashed line.

FIG. 6 shows a cross-sectional view of an embodiment of the parts important for the operation of the valve arrangement 36 and rotary distributor 38 shown schematically in FIGS. 1 and 1a; FIG. A perspective view of the triviewer 38 is shown. A group of centrifugal weights 61 is inserted into the drive of the rotary distributor 38, the centrifugal weights 62 acting on the adjusting sleeve 63.
When the adjusting sleeve 63 undergoes an axial movement in relation to the centrifugal force against the force of the adjusting spring 66, the action of the pin 6 and the slot 65 causes the rotary distributor 3 to
8 rotates relative to its drive portion 11, thereby changing the injection starting point. A cutout 40, which is bounded in one direction by a control surface 41 in the rotary distributor 38, connects the supply conduit 19 via a control opening 42b and a portion of the conduit 42.
A control opening 42a, which can be closed by a control surface 41 for controlling the injection period, is connected to the control pressure line 31.
The axial movement of the rotary distributor 38 for controlling the conveyance amount can be effected via the lever 67 to stop the conveyance or to correct the conveyance amount; on the other hand, the regulating springs 68a, 68b and 68c can be adjusted. This can be done via the adjustment lever 69. The force of the regulating spring is transmitted via the intermediate lever 71.

FIG. 7 shows the mechanical valve device 3 used in FIGS. 1, 1a, 6 and 6a.
Six variant embodiments are illustrated. The valve arrangement, designated 36' in FIG. Depending on the axis,
Alternatively, as shown, it is driven by the camshaft 11 itself via a play-free coupling, for example a diaphragm coupling. In FIG. 7, the coupling is shown as a pawl coupling 93 offset by 45 DEG to simplify the drawing. The control sleeve 92 has a central vertical hole 9
4 has a dosing slide 95 which is longitudinally movable for changing the conveying amount and rotatable for changing the injection starting point, but is otherwise stationary. The slider has four control surfaces designated 41'. Metering slider 9
The control sleeve 92, which is arranged concentrically around the control sleeve 92, has only one control hole 96, which is formed as a radial hole and is located in a plane perpendicular to the longitudinal axis of the control sleeve 92. and
This opens into a ring groove 98 formed on the outer periphery of the control sleeve 92, which itself opens into a conduit 42 which leads to the control pressure conduit 31 via a control opening 42a in the casing 91.
It is connected to the part of A recess 40', which is axially bounded on one side by a control surface 41', connects the control opening 4 in the casing 91 via a radial bore 97 of the control sleeve 92 and an annular groove 100.
2b and via this control opening 42b and part of the conduit 42 the supply conduit 1.
9 is connected. The longitudinal movement of the metering slide 95 required for changing the conveyance amount takes place via a lever 99, and the pivoting movement required for changing the injection start point takes place via a lever 101. Both levers can be actuated via known mechanical or electromechanical governors or injection regulators, and hydraulic or electrohydraulic regulating elements can be attached to these levers 99 and 101. It can also be engaged.

The fuel injection device described in the above embodiments is equipped with a pump nozzle. This is because in this case the advantages of the hydraulic control device according to the invention are maximized. However, the principles of the invention can also be applied to single pumps as well as injection pumps combined into bank pumps.

Since the present invention is configured as described above, it has the following remarkable effects. That is, a sufficiently high control pressure P _S can be generated by means of the conveying pump 33 in a control conduit 29 separate from the filling conduit 21, and the control pressure conduit and the filling conduit 21 are clearly separated; The precise control allows the fuel injection system to be used in high speed diesel engines. Also, additional control pumps, which require separate drives,
Alternatively, mechanical control parts for individual injection pumps are not used, making the entire fuel injection system compact and inexpensive.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of the first embodiment, FIG. 1a is a partial sectional view taken along the line - in FIG. 1, and FIG.
The figure is a schematic sectional view of the second embodiment, Figure 2a is a diagram showing a modified embodiment of the control slider, and Figure 3 is a diagram showing the third embodiment.
A schematic sectional view of the embodiment, FIG. 4 is a schematic partial view of the fourth embodiment, FIG. 5 is a control diagram of the magnetic valve device, and FIG. 6 is a diagram of the valve device used in FIG. Partial sectional view, Figure 6a is a perspective view of the rotary distributor used in the same valve device, Figure 7
The figure is a schematic cross-sectional view of a valve arrangement of a modified embodiment. 10a-10d'...Pump nozzle, 11...Camshaft, 11a-11d'...Drive cam, 12a-12d
...Injection pump, 13...Injection nozzle, 14a-14
d'...Pump piston, 15...Plunger spring, 1
6...Roller plunger, 17...Cylinder hole, 18
... pump working chamber, 19 ... supply conduit, 21 ... filling conduit, 22 ... overflow conduit, 23 ... return spring, 24 and 24' ... control slider, 24a ... section, 25 ... spring chamber, 26 ... passage, 27 and 27'
...Control point, 28...Pressure chamber, 29...Control conduit, 3
1... Control pressure conduit, 31a and 31b... portion, 3
2... Control fuel source, 33... Conveying pump, 34... Tank, 35... Pressure limiting valve, 36 and 36'... Valve device,
37...pressure limiting valve, 38...rotary distributor, 39...outer surface, 40 and 40'...notch,
41 and 41'...control surface, 42-42''...conduit, 4
2a and 42b...control opening, 43...ring groove,
44...Arrow, 46~47''...Magnet valve, 48~4
8''... Magnetic valve device, 51... Throttle conduit, 51a... Portion, 52... Relief conduit, 53... Rotating distributor, 54... Outer shell surface, 55... Control opening, 56
...Horizontal hole, 57...Vertical hole, 59...Aperture, 61...Centrifugal weight group, 62...Centrifugal weight, 63...Adjustment sleeve, 6
4...pin, 65...slot, 66...adjustment spring, 6
7... Lever, 68a-68c... Regulating spring, 69...
Adjustment lever, 71... Intermediate lever, 91... Casing, 92... Control sleeve, 93... Pawl coupling, 94... Vertical hole, 95... Metering slider, 96... Control hole, 97... Radial hole, 98... Ring groove, 9
9...Lever, 100...Ring groove, 101...Lever.

Claims (1)

Claims: 1 Mechanically driven pump pistons 14a-14d, 14a'-14 of injection pumps 12a-12d, each one per working cylinder, supplied with fuel at supply pressure by a conveying pump 33;
d′ and all injection pumps 12, one each
a to 12d, the control slides 24, 24' being operable by the control pressure of the control fuel source 32 common to the pumps, at least against the force of the return spring 23; It is inserted into an overflow conduit 22 permanently connected to the chamber 18, which closes this overflow conduit 22 for the start of injection and reopens it for the end of the injection, and also controls devices 36, 36', 48. ,4
8', 48'', and the control device 36, 36', 4
8, 48', 48'', the control pressure is connected to the control conduit 2.
Pressure chamber 2 of control slide 24, 24' via 9
(a) In the fuel injection device for an internal combustion engine that can be switched to
Control pressure Ps many times higher than supply pressure Pv of d
A transfer pump 33 configured to produce
and a first pressure control valve 35 that limits the control pressure Ps in one control pressure conduit 31 connectable to a plurality of control conduits 29, (b) a first pressure restriction; Behind the valve 35, the control conduit 2
Supply pressure in the filling conduit 21 separated from 9
A second pressure limiting valve 37 that determines Pv is connected, and (c) the control device controls all injection pumps 12a to 1.
2d, a valve arrangement 36, 36', 48, 48', 48'' which determines the starting point and duration of the pressure loading of the pressure chamber 28 of the control slide 24, 24';
This valve device 36, 36', 48, 48', 48''
and a separate distribution device 43, 53, which distributes the pressure chamber 28 of the control slide 24, 24' at the injection cycle.
in each case one of the control conduits 29 leading to can be connected to a control pressure conduit 31; (d) necessary for the operation of the control slides 24, 24';
The control pressure Ps supplied to each one of the pressure chambers 28 via the distribution device 43, 53 prevents the discharge of control fuel from the control pressure line 31 into the low-pressure line 19, as described above. ',48,
48', 48'' and then vented again towards the low pressure conduit 19 due to the return stroke of the control slides 24, 24'; injection pump 12
(f) The supply conduit 19 is connected to the valve devices 36, 36', 48,
48', 48'' serves as a low pressure conduit for the fuel discharging from the control pressure conduit 31; Fuel injection device for an internal combustion engine, characterized in that the working chamber 18 is connectable to the filling conduit 21. 2. Fuel according to claim 1, in which the conveying pump 33 is configured as a metering pump. Injection device. 3 The filling conduit 21 is connected to the spring chamber 25 containing the return spring 23 of the control slide 24, and the section of the control slide 24 between the control point 27 of the control slide 24 and the spring chamber 25 2. The fuel injection device according to claim 1, wherein the pressure chamber 28 of the control slide 24' is connected to the overflow conduit 22 via a passage 26 formed in the control slide 24a. The fuel injection device according to claim 1, which is connected to a spring chamber 25 containing a return spring 23. 5. A control slider sealed with respect to the spring chamber 25 containing a return spring 23. Claim 1, wherein the overflow conduit 22 is connectable to the relief conduit 52 by means of a ring groove 27' at 24'.
The fuel injection device described in Section 1. 6. The valve arrangement 48, 48', 48'' defines the injection start point and the injection duration.
Claim 1 configured as 48″
The fuel injection device described in Section 1. 7. The magnetic valve arrangement 48, 48', 48'' consists of two magnetic valves 46, 4 which are hydraulically supported in parallel to each other.
7, 46', 47', 46'', 47'', of which the first solenoid valve 46, which opens toward the low-pressure conduit 19 before the start of injection;
46', 46'' are switched to the second position by their switching motion.
The solenoid valves 47, 47', 47'' have already blocked the discharge of the control fuel from the control pressure conduit 31 into the low pressure conduit before the start of injection, and this discharge is interrupted and the injection is started. Start, second magnet valve 47,4
7', 47'', by their switching movement which enables said drainage, the first magnet valve 46, 46', 4
A fuel injection device according to claim 6, characterized in that the injection is terminated while the valve 6'' is still switched. 8. Both magnet valves 46' and 47' are configured as 3-port 2-position valves, These 3 ports 2
One part 31a of the control pressure conduit 31 is permanently connected to the distribution device 53 by means of a position valve.
can be connected alternately to the other part 31b of the control pressure conduit 31 connected to the control fuel source 32 or to the low pressure conduit 19.
The fuel injection device described in Section 1. 9 The first magnet valve 46 is configured as a two-port valve and connects the control pressure line 31 to the low pressure line 19.
inserted into a conduit 42' connected to the
The second magnet valve 47 is configured as a three-port, two-position valve and connects one section 31a of the control pressure conduit 31 leading to the distribution device 43 to the control fuel source 32.
8. A fuel injection device according to claim 7, which is connected to the other part 31b of the control pressure conduit 31 connected to the low pressure conduit 19 or to the other part 31b of the control pressure conduit 31 connected to the low pressure conduit 19. 10 Both magnet valves 46", 4 of the magnet valve device 48"
7″ is configured as a 2-port 2-position valve,
are respectively inserted into conduits 42', 42'' connecting the control pressure conduit 31 to the low pressure conduit 19;
11. The fuel injection device according to claim 7, wherein the first magnet valves 46, 46', 46'' connect the control pressure conduit 31 to the low pressure conduit 19. a second magnet valve 47, 47',
47'' is energizable for its switching movement which brings about the connection from the control pressure conduit 31 to the low pressure conduit 19 and terminates the injection.
The fuel injection device described in Section 1. 12 with a central rotary distributor 53 serving as a distribution device 53, which is driven synchronously with the injection pump and which has individual control conduits 29 and control pressure conduits 3 for actuating the control slides 24;
1 is made and interrupted sequentially with the injection cycle, and the rotary jacket surface 54 of said rotary distributor 53 is provided with a control opening 55 which is permanently connected to the control pressure conduit 31. The fuel injection device according to claim 1, wherein the width B of the control opening 55 in the circumferential direction is selected so that the operation period of the control slider 24 is as long as possible. 13. A central valve device 36 with a rotary distributor 38, which is driven synchronously with the injection pumps 12a-12d and is vertically movable for varying the conveyance and for starting the injection. Rotatable relative to its drive for point changes, this rotary distributor 38 is furthermore injected by means of a control surface 41 in order to control the control pressure Ps operating the control slide 24. The valve device 36 is inserted into the conduit 42 connecting the control pressure conduit 31 to the low pressure conduit 19 in order to cut off or open the connection from the controlled control conduit 29 to the low pressure conduit 19 at intervals of . 2. A fuel injection system as claimed in claim 1, wherein the rotary distributor (38) has on its outer surface (39) one control surface (41) per control conduit (29). 14 Central valve arrangement 3 with rotary valve 92
6', the rotary valve 92 of which is connected to the injection pump 12a.
~12d and controlled in the period of injection by a control surface 41' to control the control pressure Ps operating the control slides 24, 24' from the control line 29 to the low-pressure line 19. The rotary valve 92
is formed by a control sleeve 92 arranged concentrically around a dosing slide 95, which is connected to the control conduit 2 to be controlled.
9 is provided with one control surface 41' per 9, which is mounted in a control sleeve 92 longitudinally movable for changing the feed rate and rotatably for changing the injection starting point, and is connected to the low-pressure line 19. 2. A fuel injection device as claimed in claim 1, having a recess 40' which is permanently connected and bounded on one side by a control surface 41'. 15 The control sleeve 92 is provided with only one control hole 96 which is designed as a radial hole and which cooperates with the control surface 41' of the dosing slide 95, which control hole 96 forms a ring groove on the outer circumference of the control sleeve 92. 15. The fuel injection device of claim 14, wherein the annular groove 98 is permanently connected to the control pressure conduit 31. 16 The distribution device 43 connects each injection pump 12a to 1
2d is formed by a control point 43 cut into each of the pump pistons 14a to 14d, by means of which the pump pistons 14a to 14d are at least in the starting position or in the bottom dead center position. In some cases, the control conduit 29 belonging to
2. The fuel injection device according to claim 1, wherein the connection from the control pressure line 31 to the control pressure line 31 is interrupted and is re-established after the first partial stroke. 17 The control part 43 is the pump piston 14a~
Ring groove 43 cut on the outer shell surface of 14d
17. The fuel injection device according to claim 16, formed by: 18 between the control fuel source 32 and the connection to the conduits 42', 42'' with the magnet valves 46'', 47'';
11. The fuel injection device according to claim 10, wherein the control pressure conduit 9 is inserted into the control pressure conduit 31.