JPH0435612B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an opposed plunger type fuel injection pump device used in a diesel engine or the like.

(Prior art) Generally, opposed plunger type fuel injection pumps are
One or more pairs of plungers are installed diametrically opposite each other on the rotor shaft, and an annular cam is arranged around the rotor shaft, and the plunger is driven by the inner periphery of the cam as the rotor shaft rotates. It's becoming like that.

(Problems to be Solved by the Invention) However, in the conventional structure, there is a problem that the mechanism for adjusting the injection characteristics (injection timing and injection rate) of the fuel injection pump is complicated and large. There is a problem in that it is difficult to set the injection characteristics to optimal values corresponding to various operating conditions of the engine.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a fuel pressure pump by arranging an annular cam for driving the plungers around a rotor shaft incorporating a plurality of opposing plungers. The fuel passage of the pump is equipped with a control device that adjusts the opening and closing timing of the passage, and the control device is provided with an annular control sleeve that fits around the outer periphery of the rotor shaft. A plurality of grooves are provided at intervals in the circumferential direction, one of the grooves is formed parallel to the axial direction, and the remaining grooves are inclined with respect to the axial direction and extend parallel to each other. is provided with a plurality of fuel passages extending radially from the fuel passage in the shaft, and configured to sequentially and intermittently communicate the fuel passages with the groove as the rotor shaft rotates;
As a result, the injection amount is changed by moving the control sleeve in the axial direction, and the range of use of the cam is changed by moving the control sleeve in the circumferential direction, thereby changing the injection rate. A sleeve angle position adjustment mechanism that rotates the control sleeve according to the state is connected, and an axial movement mechanism that moves the control sleeve in the axial direction is connected, and the cam is rotated according to the engine operating conditions to the annular cam. A cam angle position adjustment mechanism to be moved is connected, and an electromagnetic actuator is provided in the axial direction movement mechanism, the sleeve angle position adjustment mechanism, and the cam angle position adjustment mechanism, and the operation of these actuators is controlled according to the operating state of the engine. It is characterized by being equipped with a control device to

(Function) According to the above configuration, the actuator changes the angular positions of the control sleeve and the annular cam according to the operating conditions of the engine. As a result, the timing at which the fuel passage is closed changes, and the section of the cam surface that drives the plunger (the area in which the cam surface is used) changes during the passage closure period, and as a result, the fuel injection rate (rotor shaft (fuel injection amount per unit rotation angle) is changed and set to the optimum value. Further, although the injection timing changes as the usage range of the cam surface changes, the injection timing can be set to an optimal value by rotating the cam using the cam angle position adjustment mechanism.

(Embodiment) In FIG. 1, inside a casing assembly 1 of a fuel injection pump, a pair of pump shaft 2 and a rotor shaft 3 are arranged approximately concentrically and connected to each other by an Oldham joint 5. The pump shaft 2 is connected to the output shaft of the engine via a mechanism not shown. A rotor 7 of a feed pump 6 is attached to the pump shaft 2 near the Oldham joint 5. The inlet 6a of the fuel feed pump 6 is connected to the fuel tank via an internal passage 9 of the casing assembly 1, a coupling 10, and an external passage (not shown). The outlet 6b of the feed pump 6 is connected to the chamber 12 via a passage 11 inside the casing assembly 1.

An end 13 of the rotor shaft 3 opposite to the Oldham joint 5 is inserted into the chamber 12, and a control device 16 is formed by the end 13 and an annular control sleeve 15 that fits around the outer periphery of the end 13. The control device 16 is configured to adjust fuel injection characteristics as will be described later, and the chamber 12 is connected to a passage 17 inside the rotor shaft 3 via the control device 16. aisle 17
extends in the longitudinal direction of the center of the rotor shaft 3, and near the Oldham joint 5, the pressure pump 2
It is connected to the pump chamber 21 of No. 0.

One outlet passage 22 extending from the passage 17 to the outer peripheral surface of the rotor shaft 3 is radially provided in the longitudinally intermediate portion of the rotor shaft 3, and one end of each of the casing assemblies 1 is connected to the passage 22. A plurality of passages 23 (the same number as the number of cylinders of the engine) are provided. The other end of the passage 23 is connected to the inlet of a delivery valve 25 fixed to the casing assembly 1. Although not shown, the outlet of the delivery valve 25 is connected to the fuel injection valve of each cylinder via a high-pressure fuel pipe, and the fuel pressurized by the pressure pump 20 is transferred to the passages 17, 22, 23, and the delivery valve 25. The fuel is then sent to the fuel injection valve and injected into the fuel chamber.

A fuel cutoff valve 26 consisting of a solenoid valve is provided at the downstream portion of the passage 11. The fuel cutoff valve 26 is for closing the passage 11 to stop the engine, and is fixed to the casing assembly 1. Further, a pressure regulating valve 27 is provided at the upstream portion of the passage 11. A pressure regulating valve 27 is also incorporated into the casing assembly 1, and its relief passage 28 is connected to the passage 9 on the pump inlet 6a side.

According to this configuration, the passage 11
is closed, the pressure regulating valve 27 opens in response to the discharge pressure of the pump 6, and the inlet 6a and outlet 6 of the pump 6 are closed.
b is connected via a passage 28. Therefore, it is possible to prevent abnormally high pressure (pump discharge pressure) from being applied to the passage 11 when fuel is cut off, and damage to the pump 6, seals, etc. can be prevented.

As shown in FIG. 2, which is a partial cross-sectional view of FIG. Both plungers 30 are slidably fitted into diametrical holes provided in the large diameter portion (rotor) of the rotor shaft 3. The pump chamber 21 is formed between both plungers 30. The end of each plunger 30 opposite to the pump chamber 21 is connected to the shoe 3.
2 and a roller 33, it is in contact with a cam surface 35 on the inner circumference of the cam 31. The shoe 32 is the rotor shaft 3
The roller 33 is slidably fitted into a notch on the outer periphery of the roller 33, and holds the roller 33 rotatably. Also cam 31
is rotatably attached to the casing assembly 1 (housing), and its rotational angular position is adjusted by a cam angular position adjustment mechanism 40.

The cam angle position adjustment mechanism 40 includes a cylinder 41 fixed to the casing assembly 1, a piston 42 slidably fitted into the cylinder 41, and the like. Further, an actuator 49 consisting of a step motor is attached to the cylinder 41. An operating rod 50 of the actuator 49 is connected to a fixed pin 52 at the center of the piston 42 via a compression coil spring 51. Spring 51
A hydraulic chamber 53 is formed between the end of the piston 42 and the body of the actuator 49 in the vicinity of the piston 42 . The hydraulic chamber 53 is connected to the chamber 12 via a passage 54.
is connected to. Furthermore, a pin 47 is attached to the longitudinally intermediate portion of the piston 42. The pin 47 is fitted into a diametrical hole in the piston 42, and one end thereof is fitted into a hole 48 in the cam 31.

According to the above configuration, as the rotor shaft 3 rotates, the cam surface 35 pushes the plunger 30, so that fuel is pressurized in the pump chamber 21 and is sent to the fuel injection valve as described above. When the roller 33 passes the top of the cam surface 35 and the plunger 30 is ready to move outward, fuel is supplied from the feed pump 6 shown in FIG. 1 to the pump chamber 21 through the passages 11, 17, etc. .

In the pressurizing operation, when the angular position of the cam 31 changes, the section (usage area) of the cam surface 35 that pushes the roller 33 during the actual fuel injection operation (pressurizing operation) changes. Therefore, the lift and moving speed of the roller 33 during the injection operation change, and the fuel injection rate changes. Therefore, the cam angle position adjustment mechanism 4
By changing the angular position of the cam 31 by 0, the fuel injection rate is adjusted.

Further, as will be described later, the actuator 49 moves the rod 50 in response to the engine speed and load, and when the engine speed and load change, the rod 50 moves the piston 42.
Piston 42 rotates cam 31 via pin 47. Therefore, the angular position of the cam 31, that is, the injection rate, is set in accordance with the engine rotation speed and the like. On the other hand, the feed pump 6 in FIG. 1 is driven by the engine output shaft, and the hydraulic pressure introduced from the feed pump 6 into the hydraulic chamber 53 via the passage 11 and the passage 54 in FIG. 2 also corresponds to the engine rotation speed. are doing. Therefore, when the engine speed changes, the force applied from the hydraulic chamber 53 to the piston 42 also changes. In this way, a force corresponding to the engine speed is also applied to the piston 42 from the hydraulic chamber 53, so that by just applying a small force from the actuator 49, the piston 42
2 moves reliably and quickly, and the force required of actuator 49 is small.

As shown in FIG. 1, a governor 55 is attached to the casing assembly 1. The governor 55 includes an actuator 61 consisting of a linear solenoid. As will be described later, the actuator 61 operates in response to changes in engine speed and load, and is operatively connected to an axial movement mechanism for moving the control sleeve 15 in the axial direction. The axial movement mechanism is composed of a pin 59, an eccentric pin 60, etc., and is connected to the actuator 61 via a rod 62. That is, when the actuator 61 moves the rod 62 in its longitudinal direction, the pin 59 rotates and the eccentric pin 60 at the tip of the pin 59 moves in the axial direction of the rotor shaft 3.

As shown in FIG. 1 and FIG. 3, which is a schematic cross-sectional view of FIG. 1, the control sleeve 15
is a notch 65 extending in the circumferential direction in a part of the outer periphery.
and a notch 66 extending in the axial direction on the outer circumference. The pin 60 is fitted into a circumferential notch 65, and as the pin 59 rotates, the control sleeve 15 is moved in the axial direction. Further, a pin 71 of a sleeve angle position adjustment mechanism 70 is fitted into the axial notch 66, and the control sleeve 15 is rotated by the pin 71.

The sleeve angle position adjustment mechanism 70 is constructed by incorporating a piston 73 extending in the tangential direction of the control sleeve 15 into a cylinder 72 provided in the casing assembly 1, and the pin 71 is connected to the piston 7.
It is fitted into a diametrical hole in the longitudinally intermediate portion of No. 3. At one end of the piston 73 is an actuating rod 8 of an actuator 80 consisting of a step motor.
1 is in contact. A snap spring 8 fixed to the other end of the piston 73 and the inner circumference of the cylinder 72
A compression coil spring 84 is provided between 3 and 3. Further, both ends of the piston 73 face hydraulic chambers 85 and 86, and these hydraulic chambers 85 and 86 communicate with the chamber 12 via passages 87, respectively.

As shown in FIG. 4, which is an enlarged schematic view of FIG. 3, and FIG. 5, which is a developed view of the inner surface of the control sleeve 15, the inner surface of the control sleeve 15 has, for example, three grooves P spaced apart in the circumferential direction. ,Q,R
is provided. Groove P is control sleeve 15
However, the grooves Q and R extend parallel to each other and are inclined with respect to the axial direction of the control sleeve 15. Therefore, the groove Q has one end qa
is farthest from the groove P in the circumferential direction, and the other end
qb is closest to groove P. Further, the rotor shaft 3 is provided with, for example, four passages S1 to S4 that extend radially from the passage 17 to the outer periphery of the rotor shaft 3.

According to the above configuration, as the rotor shaft 3 rotates, the passages S1 to S4 are intermittently connected to the grooves P, Q, and R, thereby adjusting the injection characteristics as follows.

In the illustrated embodiment, passage S1 in FIG.
When there is no communication with Q and R, that is, when the passage 17 is closed to the chamber 12, fuel injection is started. After this operation, for example, passage S1
The passage S2 located at the front in the rotational direction is the groove Q
When the passage 17 is opened to the chamber 12, the fuel injection ends. In addition, the groove R
is a groove for effectively cutting fuel spill at the end of fuel injection, and at the end of fuel injection, S3 communicating with the passage 17 has a phase angle from the passage S2.
Since it also communicates with the groove R at a position shifted by 90 degrees,
Fuel spill sharp cut (fuel injection failure)
is carried out well.

In this way, the time from the start of injection to the end of injection corresponds to the time from passage S1 passing through groove P until passage S2 connects to groove Q, and the injection time is determined by the position of the control sleeve 15 in the axial direction. It changes as follows depending on. That is, when the control sleeve 15 moves in the direction of arrow M in FIG. 5 and the passages S1 to S4 move relative to the control sleeve 15 to the position shown by the dashed line in FIG. , the passage S1 passes through the groove P and then the passage S
2 to connect to the groove Q becomes longer. Also, the control sleeve 15 moves in the direction of arrow N,
When the passages S1 to S4 move relative to the control sleeve 15 to the positions indicated by broken lines in FIG. 5, the passage S2 passes through the end qb of the groove Q, and the passage S1 passes through the groove P. Then go to aisle S2
The time until it connects to the groove Q becomes shorter.

Therefore, by adjusting the axial position of the control sleeve 15 using the governor 55 shown in FIG. 1, the fuel injection time, that is, the fuel injection amount can be adjusted.

Also, by rotating the control sleeve 15 shown in FIG. 4 and changing the angular position, the passages S1 to
The timing at which S4 communicates with grooves P, Q, and R changes. Therefore, by changing the rotational angular position of the control sleeve 15 using the sleeve angular position adjustment mechanism 70 shown in FIG. 3, the timing of fuel injection is changed, and with the change in timing,
During the injection operation, the section (use area) of the cam surface 35 that pushes the plunger 30 changes, and the injection rate changes.

The actuator 80 moves the rod 81 in response to the engine speed and load. Therefore, when the engine speed and load change, the piston 73 is pushed by the rod 81 and is controlled. Rotate the sleeve 15. Therefore, the angular position of the control sleeve 15, that is, the injection timing and injection rate, are set to optimal values in accordance with the engine speed and load.

The operation of each of the actuators 49, 61, and 80 described above is controlled by a control device (not shown) (microcomputer: not shown). The load sensor 88 shown in FIG. 1 and the rotation sensor 89 shown in FIG. 3 are connected to the control device, and the control device controls the operation of the actuators 49, 61, and 80 based on signals from these ground detectors. It's becoming like that. The above load sensor 88
is attached to Governor 55. The rotation sensor 89 is adapted to detect the teeth of a large-diameter gear 90 provided at the end of the pump shaft 2 shown in FIG. 1 by means of a pick-up portion 91 shown in FIG. The appearance of the illustrated apparatus is as shown in FIG.

(Effects of the Invention) As explained above, according to the present invention, the injection rate and injection timing are adjusted by changing the angular positions of the control sleeve 15 and the cam 31 of the pressure pump 20, thereby improving the fuel injection characteristics. At the same time, the structure can be simplified and lightened. In addition, the moving parts (control sleeve 15 and cam 31) are connected to an electromagnetic actuator 49,
80, the movement of the moving part, that is, the fuel injection state, can be made to accurately and quickly follow the engine operating state, and even in engines where the operating state changes greatly, such as a high-speed engine, Engine performance can be improved by maintaining optimal injection conditions. In other words, since the moving parts for control are lightweight and simple, they can be moved by the actuators 49 and 80, and the followability of the fuel injection state can be improved as described above.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a cross-sectional view of an embodiment of the present invention.
Figure 3 is a partial cross-sectional view of Figure 1.
4 is a schematic enlarged view of FIG. 3, FIG. 5 is a schematic exploded view of FIG. 4, and FIG. 6 is a schematic side view of the apparatus of the embodiment. 3... Rotor shaft, 15... Control sleeve, 16... Control device, 20... Fuel pressure pump, 30... Plunger, 31... Cam,
40...Cam angle position adjustment mechanism, 49,80...
Actuator, 70... Sleeve angle position adjustment mechanism.

Claims (1)

[Claims] 1 An annular cam 31 for driving the plungers is installed around the rotor shaft 3 in which a plurality of opposing plungers 30 are incorporated.
A fuel pressure feeding pump 20 is constructed by arranging the fuel pressure pump 20, and a control device 16 for adjusting the opening/closing timing of the passage 17 is provided in the fuel passage 17 of the pump 20,
The control device 16 is provided with an annular control sleeve 15 that fits around the outer periphery of the rotor shaft 3, and a plurality of grooves P, Q, and R are provided on the inner peripheral surface of the control sleeve 15 at intervals in the circumferential direction. ,
One of the grooves P, Q, and R is formed parallel to the axial direction, and the remaining grooves Q and R are inclined with respect to the axial direction and extend parallel to each other. A plurality of fuel passages S1, S2, S3, and S4 are provided that extend radially from the fuel passage 17 inside, and as the rotor shaft 3 rotates, the fuel passages S1, S2, and
3. S4 is configured to communicate with the grooves P, Q, and R intermittently in sequence, thereby changing the injection amount by moving the control sleeve 15 in the axial direction, and changing the injection amount by moving the control sleeve 15 in the circumferential direction. The injection rate is changed by changing the usage range of the cam 31, and the control sleeve 15 is
A sleeve angle position adjustment mechanism 70 that rotates the control sleeve 15 in accordance with the operating state of the engine is connected to the annular cam 31, and an axial movement mechanism that moves the control sleeve 15 in the axial direction is connected to the annular cam 31. A cam angle position adjustment mechanism 40 is connected to rotate the cam 31 according to the operating conditions of the cam 31, and electromagnetic actuators 61, 80, 49
1. A fuel injection pump device comprising: a control device for controlling the operation of these actuators 61, 80, and 49 according to the operating state of the engine.