JPH0463206B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes a fuel supply pump that delivers fuel into the inner chamber of an injection pump in proportion to the rotational speed and generates a corresponding delivery pressure at this time, and a centrifugal weight regulator. a rotation speed regulator with an adjusting sleeve for actuating a control member to change the injection quantity and the outflow passage starting from the outer circumferential wall of the adjusting sleeve and extending partially into the casing of the centrifugal weight regulator. guided through a shaft fixed to
and the outflow channel is controlled via a throttle formed in the adjusting sleeve or shaft and consisting of an annular groove cooperating with a control slot,
A regulating sleeve at the same time controls an outflow passage extending from the inner chamber to the suction side of the fuel supply pump, the fuel in the outflow passage being directed into a control chamber downstream of said throttle, said control chamber being on one side. The present invention relates to a fuel injection pump, in which a first movable wall is controlled in the outflow passage, and an additional restriction is provided in the outflow passage downstream of the movable wall.

BACKGROUND OF THE INVENTION When detecting a load signal in a fuel injection pump of the type mentioned above, which is known from German Patent Application No. 21 58 689, the interior of the fuel injection pump is controlled by means of an adjusting sleeve. The pressure relief in the inner chamber is particularly provided by means of the outflow duct, so that the pressure in the inner chamber can also be varied as a function of the load in accordance with the load-dependent adjustment position of the adjustment sleeve. . Such pressure changes in the inner chamber are intended for load-dependent regulation of the injection regulator, which in turn is rotational speed-dependent in order to take into account both parameters for the start of fuel injection. will also be adjusted. The method of detecting the load signal in such known fuel injection pumps has become purely mechanically regulated.

In addition, the Federal Republic of Germany patent application publication no.
In the fuel injection pump known from German Patent No. 2847248, an inductive travel distance signal generator that moves inside the fuel injection pump is arranged, which travel distance signal generator is controlled by mechanical rotation. Detecting the various positions of the adjusting rod of the number adjuster. However, such known fuel injection pumps have significant structural limitations and require the provision of a corresponding construction space for receiving the travel distance signal generator.

Problem to be Solved by the Invention It is an object of the invention to detect a load signal without significantly modifying the fuel injection pump or without arranging a travel distance signal generator in the fuel injection pump. Our goal is to provide fuel injection pumps that can.

Means for Solving the Problems The means of the present invention taken to solve the above-mentioned problems is that the throttle is an outflow valve consisting of a first movable wall and a control slit, and the outflow valve is a first movable wall and a control slit. It is adapted to be operated by a movable wall, furthermore, the outflow valve is arranged downstream and the outflow passage is arranged through the end section.
Connected to the suction side of the fuel supply pump,
A first movable wall and a second movable wall of the control room are rigidly connected to each other so as to be reciprocal, and the second movable wall has a smaller working surface than the first movable wall. The fuel pressure generated in the inner chamber acts on the surface and is used to detect the axial position of both movable walls by means of a travel distance measuring system as a measurement signal corresponding to the load. It's about being familiar.

Advantages of the Invention The present invention has the advantage that a load signal can be detected without making significant changes to the fuel injection pump or without having to place a travel distance signal generator inside the fuel injection pump. can get.

Embodiment A pump drive shaft 2 is supported in a casing 1 of a fuel injection pump for a multi-cylinder internal fuel engine. This drive shaft is connected to a cam disk 3, which has the same number of cams 4 as the number of cylinders of the internal combustion engine. The raceway surface of the cam disk rests on a roller (not shown), which is supported in a ring 6 which is fitted into the pump casing and in which a bolt is engaged. 7, it is rotatable about the axis of the drive shaft 2. The pump and distributor 8 has a collar 9 at its drive end, which collar is connected to the cam disk by a pin 10.

On top of the brim 9, there are two sliding plates 1 above and below each other.
1, and a disk 12 having a spherical upper portion is placed on the sliding plate. A corresponding surface of a yoke 13 formed correspondingly to the disk is crimped onto this disk by two coil springs 14 parallel to the axes and arranged 180 degrees apart. Only one of the springs, located behind the pump and distribution member, is shown. These coil springs are supported by the pump body 15, which closes the pump casing. Under the action of the coil spring 14, the cam disk 3 is pressed against the roller in the ring 6.

The pump and distribution member 8 slides within a cylinder bush 17, which is seated fixedly within the pump body 15. The pump body is closed at the top by a screw-in cap 19 which presses the valve seat body 20 onto the end face of the cylinder bush 17. A valve member 21 slides within the valve seat body 20 and is pressed against the valve seat body 20 by a spring 22 in the closed position. The valve seat body 20 and the valve member 21 form a pressure valve.

A rotating positive displacement pump is disposed on the drive shaft 2, and the positive displacement pump is connected to the fuel supply pump 2.
4 and delivers fuel directly into the interior chamber 26 of the pump casing 1. A passage 27 branches from the inner chamber 26, and this passage is connected to the cylinder bush 1.
7 into an inlet passageway 28 . This inlet passage 28 cooperates with a longitudinal groove 29 provided in the end section of the pump and distribution element 8 . The longitudinal groove opens into a pump working chamber 30, to which a pressure valve is further connected. Screw-in cap 1
9 from the chamber located upstream of the pressure valve in the flow direction into the valve seat body 20 and into the cylinder bush 17.
A channel 31 provided in the wall of the device branches out and opens into a radial channel 32 . The passage 32 cooperates with an annular passage 33 in the pump and distribution member. A distribution groove 34 in the pump and distribution element branches off from the annular passage 33, which distribution groove cooperates with an outlet passage 35, only one of which is shown here. The outlet channel extends radially in the cylinder bush 17 but is inclined in the pump body 15 and opens into an outlet connection opening 36 . This outlet connection opening serves for connecting an injection nozzle (not shown) of the internal combustion engine. Like the cams 4 of the cam disk 3, outlet channels 35 with longitudinal grooves 29 and outlet connection openings 36 are also provided as many as there are cylinders of the internal combustion engine.

From the pump work chamber 30 an axial passage 38 extends into a transverse passage 39 in the pump and distribution element 8 . The opening of this transverse passage 39 into the outer circumferential wall of the pump-and-distributor element 8 cooperates with a control sleeve 41 that is axially slidable on the pump-and-distributor element 8 . For this purpose, one spherically formed arm 42 of two-armed levers 42, 43 supported on a pin 44 is engaged in the notch of the control sleeve 41. The pin is
It sits eccentrically on the end face of a shaft 45 mounted in the pump housing, which shaft serves for regulating the full-load fuel quantity and for interrupting the fuel quantity.

Acting on the other arm 43 of the two-armed levers 42, 43 is a spherically shaped end of an adjusting sleeve 47, which serves as an adjusting member for the speed regulator and is connected to the pump casing. It is slidable along an adjustment shaft 48 which is fixedly arranged within 1. A gearwheel 49 is rotatable on the adjustment shaft, which meshes with a gearwheel 50 fixedly arranged on the pump drive shaft 2 . The gear 49 is fixedly connected to a pocket-shaped part 51 formed from a sheet metal, in which a centrifugal weight 52 is supported. This centrifugal weight is
The projection 53 engages the adjustment sleeve 47 .

The arms 43 of the two-armed levers 42 and 43 are provided with a push spring 54 and a tension spring 5 as adjustment springs.
5 is at work. The push spring 54 is directly connected to the arm 4
3, but in the illustrated embodiment is supported by a bot 56. One end of a tension spring 55 is suspended from the bolt, and the other end is engaged with a pin 57. The pin 57 is attached to an adjusting lever 58, which can be adjusted from outside the pump casing 1 in order to adjust the rotational speed to be controlled. The adjusting sleeve has a control slot 60 in the radial direction, which cooperates with an annular groove 61 provided on the outer circumference of the adjusting shaft 48 and which, by means of the control slot 60 and the annular groove 61, provides a constriction. It forms a part. The annular groove 61 is in constant communication with a vertical hole 62, which ends in a transverse hole 63.

The bolt 7 is inserted by means of its end section projecting from the pump casing 1 into a cylindrical hinge part 66, which is rotatably arranged in a piston 67 of the hydraulic regulator. 2
), the casing 68 of the hydraulic regulator is connected to the pump casing 1 of the injection pump (first
), the piston 67 is loaded on one side by the pressure in the interior chamber 26 of the pump housing 1 via a passage 69 . A spring 70 is crimped onto the other piston side, and the piston side communicates with the suction side of the fuel supply pump 24 via a passage 71.

The fuel injection pump operates as follows: With the internal combustion engine in operation, the drive shaft 2 of the injection pump and thus also the cam disc 3 are rotating, which cam disc cooperates with the rollers of the ring 6 to act as a pump and distributor. axially reciprocating and simultaneous movement of the member 8; In this case cam disk 3
is constantly in contact with the roller by the spring force of the coil spring 14 which acts as a return guide spring.
The pump and distribution member 8 is shown in the bottom dead center position. Pump work chamber 30 is filled with fuel that has entered through inlet passage 28 . cam disc 3
When the is rotated, first of all the inlet passage 28 is closed. During the now continuing discharge stroke of the pump and distribution element 8, fuel flows from the pump working chamber 30 via the open pressure valve through the channels 31, 32 into the annular channel 33 and from there via the distribution groove 34. It is delivered to one of the outlet channels 35 and to the outlet connection opening 36 assigned thereto. From here the fuel reaches one of the injection nozzles of the internal combustion engine.

The fuel supply pump 24 is connected to the inner chamber 26 of the injection pump.
The fuel is delivered under speed-dependent pressure into the engine, which pressure acts on the piston 67 of the hydraulic regulator and causes the ring 6 to be adjusted in a speed-dependent manner. The rotational position of defines the start of delivery of the injection pump.

As the speed increases, the centrifugal weight 52 of the speed regulator moves outwards and causes the adjusting sleeve 47 to slide upwards against the force of the adjusting spring. In this case, first of all, the pressure spring 54, which serves to adjust the no-load operating speed, is compressed, and then the tension spring 55, which serves to adjust the operating speed, is tensioned. During this movement of the regulating sleeve 47, on the one hand, the control sleeve 41 is pushed downwards, with the result that the amount of fuel delivered by the injection pump is reduced (partial load), and on the other hand, the annular groove 61 of the regulating shaft is Adjustment sleeve 47
is opened by the control slot 60 of the pump housing 1, so that fuel can escape from the interior chamber 26 of the pump housing 1. An annular groove 61, a vertical hole 62 and a horizontal hole 63 in the adjustment shaft 48 starting from the control slit 60
The outflow passage, which is guided further through the pump housing 1 of the fuel injection pump, reaches into the control chamber 77 inside the measuring housing 78 via a partial conduit 76 which extends outside the pump housing 1 of the fuel injection pump, so that the pump housing 1 is further guided in a partial region. It extends through an inclined hole 75 inside. The control chamber 77 is formed in one stepped cylinder bore 79 , the other cylinder bore 80 having a smaller diameter than the cylinder bore 79 . A stepped piston is slidably arranged in the stepped cylinder bores 79 , 80 , the piston portion 81 having the larger diameter being slidably disposed in the stepped cylinder bore 79 , 80 . The piston parts 82, which have a smaller diameter, each project into the cylinder bore 80. The piston part 81 delimits the control chamber 77 on one side with a first end face as a first movable wall 83, whereas the piston part 82 delimits the control chamber 77 as a second movable wall 84. The pressure chamber 85 is delimited on one side by the end face 2 . The pressure chamber 85 is communicated with the inner chamber 26 of the fuel injection pump via a pressure conduit 86, and as a result, a fuel pressure proportional to the rotational speed in the inner chamber 26 is always prevailing in the pressure chamber 85. There is. The axial position of the piston parts 81, 82 in the stepped cylinder bores 79, 80 can be detected by means of a travel distance measuring system 87 of known type and is determined by the voltage U=f(Q). As a travel distance measurement system, for example an inductive travel distance signal generator, a short-circuit ring signal transmitter or the like, the voltage is a measuring signal for the load that can be identified with the regulated fuel quantity Q. It is good to use it. In response to the force of the fuel pressure acting on the first movable wall 83 or the second end face 84 of the piston parts 81, 82, the piston parts 81, 82 move into the stepped cylinder bore 7.
9, 80 and thus opens the control slit 88 to a greater or lesser extent by means of the first movable wall 83. This control slot 88 is formed in the wall of the cylinder bore 79 in the area of the control chamber 77 and, together with the first movable wall 83, forms an outflow valve through which fuel can be removed from the control chamber 77. flows out, which allows fuel to reach the inlet hole, ie to the suction side 65 of the fuel supply pump 24, via the end section 89 extending downstream of the outflow channel. In the description so far, starting from the control slot 60, the annular groove 61, the vertical hole 62, the horizontal hole 63, the inclined hole 75, the partial conduit 76, the control chamber 77, the control slot 88 and up to the end section 89 are explained. It can be seen that an outflow passage is formed. The control slot 88 preferably has a rectangular cross section, similar to the control slot 60 in the adjusting sleeve 47. Advantageously, the control slots 60 and 88 have the same width and the ratio of the first movable wall 83 of the piston part 81 and the second movable wall 84 of the piston part 82 of the stepped piston is 2:1. be. Thereby, the ratio between the pressure in the control chamber 77 and the pressure in the pressure chamber 85 is 1:2, that is, the pressure in the control slits 60 and 85 is 1:2.
The pressure drops at 8 are equal. Since the flow rates are likewise equal, the piston parts 81, 82 in each case
The sliding movement of the adjustment sleeve 47 is followed until the above conditions are met. The piston parts 81, 82 advance the same distance as the adjusting sleeve 47 under selected conditions. Since the regulated fuel quantity Q is proportional to the load, a measuring signal can be extracted in the travel distance measuring system 87 in the form of a voltage U=f(Q), which voltage corresponds to the load. A leakage chamber 90 on the side of the stepped cylinder bore 79 opposite the control chamber 77 can communicate via a leakage conduit 91 with the end section 89 of the outflow channel.

If the adjusting sleeve 47 is in the same position during pressure fluctuations defined by the rotational speed change in the inner chamber 26, the piston part 8 of the stepped piston
The positions of 1 and 82 do not change. This is because the force changes defined by the pressure fluctuations acting on the piston parts 81, 82 are equal depending on said values.

Advantageously, in order to obtain a speed-dependent measurement signal, a cylinder bore 92 can be provided in the measuring housing 78, in which a measuring piston 93 is slidably mounted. controls a measuring chamber 95 on one side by a measuring end face 94 as a movable wall and is loaded on the other side by a pressure spring 96, which presses into the cylinder bore 92. It is located in a spring chamber 97 formed in , which is in communication with the end section 98 of the outflow channel via a leakage conduit 98 . A fuel pressure proportional to the rotational speed in the inner chamber 26 prevails in the measuring chamber 95, and for this reason, for example, the measuring chamber 95 can be communicated with the pressure chamber 85 via a conduit 99. The axial position of the measuring piston 93 can be detected by a travel distance measuring system 100 of known type, in which a voltage U=f(n ) can be taken out.

The inventive detection of the load signal and the rotational speed signal with the aid of a hydraulic component therefore does not require any spatial changes in the pump housing 1 of the fuel injection pump, apart from the provision of the hydraulic connection. do not need.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a fuel injection pump according to the present invention, and FIG. 2 is a sectional view taken along the line - in FIG. 1... Pump casing, 2... Pump drive shaft, 3... Cam disk, 4... Cam, 6... Ring, 7... Bolt, 8... Pump and distribution member,
9...Brim, 10...Pin, 11...Sliding plate, 1
2... Disk, 13... Yoke, 14... Coil spring, 15... Pump body, 17... Cylinder bush, 19... Screw-in cap, 20... Valve seat body, 21... Valve member, 22... Spring, 24... Fuel supply pump, 26... Inner chamber, 27, 31, 3
2, 38, 69, 71... Passage, 28... Inlet passage, 29... Vertical groove, 30... Pump work chamber, 33
... Annular passage, 34 ... Distribution groove, 35 ... Outlet passage, 36 ... Outlet connection opening, 39 ... Lateral passage, 41 ... Control sleeve, 42, 43
... Arm of two-armed lever, 44, 57 ... Pin, 45 ... Shaft, 47 ... Adjustment sleeve, 48 ...
...adjustment shaft, 49, 50 ... gear, 51 ... pocket-shaped part, 52 ... centrifugal weight, 53 ... protrusion, 5
4,96...press spring, 55...tension spring,
56...Bolt, 58...Adjustment lever, 60,8
8... Control slit, 61... Annular groove, 62...
Vertical hole, 63... Horizontal hole, 65... Suction side, 66
...Cylindrical hinge part, 67...Piston, 68...
...Casing, 70...Spring, 75...Slanted hole,
76...Partial conduit, 77...Control room, 79,80
... Cylinder hole, 81, 82 ... Piston part,
83, 84...Movable wall, 85...Pressure chamber, 86...
...pressure conduit, 87,100...stroke distance measurement system,
89... End section, 90... Leak chamber, 91, 98
...Leakage conduit, 92 ... Cylinder hole, 93 ... Measurement piston, 94 ... Measurement end face, 95 ... Measurement chamber, 97 ... Spring chamber, 99 ... Conduit.

Claims (1)

[Claims] 1. A fuel supply pump that delivers fuel into the inner chamber of the fuel injection pump in proportion to the rotational speed and generates a corresponding delivery pressure at this time, and a centrifugal weight regulator that works to control the injection amount. a rotation speed regulator with an adjusting sleeve for operating a control member to change the rotation speed, the outflow passage starting from the outer circumferential wall of the adjusting sleeve and partially fixed to the casing of the centrifugal weight regulator. The adjustment sleeve is guided through the shaft and the outflow channel is controlled via a throttle consisting of the adjusting sleeve or an annular groove formed in the shaft and cooperating with the control slot, so that the adjusting sleeve is at the same time , controls an outflow passage extending from the inner chamber to the suction side of the fuel supply pump, the fuel in the outflow passage being routed downstream of said throttle into a control chamber 77, which controls a In a fuel injection pump, which limits one movable wall 83 and in which an additional restriction is provided in the outflow passage downstream of said movable wall, said restriction separates from the first movable wall 83 and the control slit 88. an outflow valve consisting of a first
furthermore, an outflow valve is connected downstream via an end section 89 of the outflow channel to the suction side 65 of the fuel supply pump 24 and is connected to the control room. The first movable wall 83 and the second movable wall 84 of 77 are rigidly coupled so as to be separated from each other, and the second movable wall 84 has a smaller working surface than the first movable wall 83. The fuel pressure generated in the interior chamber 26 acts on this active surface, and the axial position of both movable walls 83, 84 is determined by a travel distance measuring system 87, which records a measurement signal corresponding to the load. A fuel injection pump characterized in that it is adapted to be used for detection. 2. said movable wall is formed by piston parts 81, 82 of a stepped piston, which piston parts are connected to a correspondingly stepped cylinder bore 7;
9 , 80 , the first movable wall 83 defines the control chamber 77 and the second movable wall 8 has a smaller diameter than the first movable wall 83 .
4. A fuel injection pump as claimed in claim 1, in which the pressure chambers 4 each limit a pressure chamber 85 on one side. 3 Piston portions 81, 8 of the stepped piston
A second movable wall 83 serves as a movable valve part of the outflow valve and a control slot 8 of the outflow valve part is formed in the cylindrical wall of the cylinder bore 79.
8. The fuel injection pump according to claim 2, wherein the fuel injection pump is configured to open the fuel injection pump. 4 Piston portions 81, 8 of the stepped piston
2 and stepped cylinder bore 7
2. The fuel injection pump according to claim 1, wherein the measuring casing 9 and 80 are provided in a measuring casing 78, which measuring casing is arranged outside the pump casing. 5. The inner chamber 26 and a measuring chamber 95 are in communication, which measuring chamber is bounded on one side by a movable wall 94, which is fitted with a pressure spring 96 on the other side. Claim 1: The adjusting force is applied and the axial position of the movable wall is detected by the travel distance setting system 100 as a measurement signal corresponding to the rotational speed. Fuel injection pump as described. 6. The movable wall is formed by a measuring piston 93, which is slidably mounted in the cylinder bore 92 and which is controlled on one side by the fuel pressure in the measuring chamber 95 and on the other side. 6. A fuel injection pump as claimed in claim 5, in which each side is loaded by a pressure spring 96. 7 The cylinder hole 92 and the measuring piston 93
7. The fuel injection pump according to claim 6, wherein the fuel injection pump is provided outside the pump casing 1 within the measuring casing 78. 8. The fuel injection pump according to claim 5, wherein an inductive stroke distance signal generator is used as the stroke distance measurement system 87,100.