JP2850019B2 - Distribution type fuel injection pump - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distribution type fuel injection pump, and more particularly to a distribution type fuel injection pump in which the injection timing is electronically controlled.

[Conventional technology]

Japanese Patent Application Laid-Open No. 57-97024 discloses a type of distribution type fuel injection pump used in a diesel engine in which a timer piston is moved by controlling a timing of a timing control valve to control an injection timing.
It is conventionally known as shown in Japanese Patent Publication No.

In this type of timer, as shown in FIG. 10, a timer piston chamber 2a is formed in a housing, and a timer piston 2b that partitions a high-pressure chamber 20 and a low-pressure chamber 21 on both sides is slidably inserted therein. A timing control valve 3 operated by a solenoid valve is mounted at an end of the housing. Then, the high-pressure chamber 20 was communicated with the pump chamber 9 by an orifice 200 and a port 201 formed in the timer piston 2b itself, and the side of the high-pressure chamber 20 was connected to the high-pressure groove 30 of the timing control valve 3 by a port 300. .
The low-pressure chamber 21 is provided with a spring 2d that constantly urges the timer piston 2b toward the high-pressure chamber. The low-pressure chamber 21 is connected to the low-pressure hole of the timing control valve 3 by a passage 32.

In this prior art, as shown in FIG. 11, a timer piston control hydraulic path is formed with respect to a pump chamber pressure Pt at an orifice 200 formed in the timer piston, and the fuel oil in the pump chamber 9 is supplied to the orifice 200 → Port 201 → High pressure chamber 20 →
It flows into the high pressure groove 30 of the timing control valve 3 via the port 300.

In the hydraulic path, the orifice 200 is
It is considered that a part of is separated. It is clear that the smaller the dead volume of the separation part, the better the timing control performance. When the conventional path is viewed dynamically, since it is the pressure of the high-pressure chamber 20 that actually moves the timer piston 2b, the ports 201, 300
Minute only dead volume V ₂ is increased. As a result, the work of changing the pressure Pt ₂ in the high-pressure chamber 20 by the leak control of the timing control valve 3 increases. In other words, in other words, there is a problem that the amount of work required to change the operating pressure of the timer piston 2b increases, and the responsiveness of the injection timing control decreases.

[Technical problem to be solved by the invention]

The basic object of the present invention is to reduce the dead volume of the above-described timer control hydraulic path by a relatively simple structure, thereby improving the responsiveness of the electronic control type timer piston and improving the injection timing control performance. An object of the present invention is to provide a distribution type fuel injection pump that can be improved.

[Means for solving the problem]

To achieve the above object, the present invention provides a timer piston for moving a roller holder assembly at a lower part of a pump housing having a pump chamber therein and a plunger capable of rotating and reciprocating according to rotation of an engine. An electromagnetic timing control valve for communicating and shutting off the high-pressure chamber and the low-pressure chamber on both axial sides of the timer piston, the timing control valve having a high-pressure groove at a high-pressure fuel inlet, At a position displaced from the high-pressure groove, a low-pressure hole communicating with the timer piston low-pressure chamber through a low-pressure passage is provided, and the high-pressure groove and the low-pressure hole are connected or blocked by opening and closing a valve operated by an electromagnetic unit. The timer piston is moved by duty control of the electromagnetic In the fuel injection pump of the type that controls the injection timing, the high-pressure groove of the timing control valve and the timer piston high-pressure chamber are connected by a passage, and the high-pressure groove and the pump chamber are directly connected by another passage having a fixed orifice. The main point is.

The present invention includes not only a case where the entire pump housing including the disc cam zone is a pump chamber but also a case where the pump chamber is formed only in a part of the pump housing.

The latter is specifically as follows. That is, the pump chamber is formed into an annular shape by an inner wall of the pump housing and a cylindrical spring seat forming a part of the plunger spring assembly, and the annular pump chamber is supplied with a fuel from a feed pump by a fuel supply path bypassing the cam chamber. , And is oil-tightly shut off from the cam chamber, which is the remaining space inside the pump housing.

[Action]

In the present invention, the flow rate of the fuel oil in the pump chamber 9 is reduced by the fixed orifice 34 provided in the pump housing 1, flows into the high-pressure groove 30 of the timing control valve 3 from the passage 33, and from there the passage 35 This causes the timer piston to flow into the high-pressure chamber 20.

When the electromagnetic portion 3c of the timing control valve 3 is energized, the needle valve opens and the high pressure groove 30 and the low pressure hole 31 at a position displaced from the high pressure groove 30 communicate with each other. Pt ₂ is passage 3
5.Timer piston low pressure chamber 2 through low pressure hole 31 and low pressure passage 32
1 and the pressure Pt ₂ in the timer piston high-pressure chamber 20 decreases. Thereby, the timer piston 2b is positioned at a position where the adjusted pressure and the spring are balanced. Therefore, by turning on and off the energization of the electromagnetic unit 3 at a desired duty ratio by the electronic control unit, the angular position of the roller holder assembly 42 is adjusted, and the timing can be freely changed.

In such control, the operating pressure for actually moving the timer piston 2b is the pressure Pt ₂ of the timer piston high pressure chamber 20, but in the present invention, the hydraulic pressure path from the pump chamber 9 on the high pressure side to the timer piston high pressure chamber 20 Is composed of a pump chamber 9, a fixed orifice 34, a passage 33, a high-pressure groove 30 and a passage 35. Therefore, the dead volume V ₁ of the from the pump chamber 9 the valve seat portion of the timing control valve 3 to (the boundary between the high pressure and low pressure) is reduced significantly. As a result, the amount of work required to change the operating pressure of the timer piston 2b can be reduced accordingly, and the response of the timer piston 2b is improved.

〔Example〕

FIG. 1 shows a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a pump housing, which is a hollow body.
1a, a cover 1b fixed to the upper opening of the body 1a,
And a distributor head 1c for closing the right end side opening of the body 1a.
Are formed. The inside of the cover 1b communicates with the pump chamber 9 via a filter.

Reference numeral 4 denotes a drive shaft which is inserted into a pump chamber 9 in the body from the left end side of the body 1a, and a protruding portion outside the body is connected to a crankshaft of an engine via a reduction gear (not shown) and driven by a diesel engine. You. A feed pump 23 is disposed coaxially at the left end of the pump chamber of the drive shaft 4, and supplies fuel oil introduced from an external tank to the pump chamber 9 via a regulating valve 800.
To be supplied. The regulating valve 800 has a function of reducing a change in the pump chamber pressure in the normal rotation range.

Reference numeral 6 denotes a plunger, which is slidably inserted into a plunger barrel 16 which is inserted and fixed to the distributor head 1c so as to be coaxial with the drive shaft 4. A fuel pressurizing chamber is provided at the top of the plunger 6 and at the bottom of the plunger barrel 16.
68 is formed. When the plunger barrel 16 is a cylindrical body, the fuel pressurizing chamber 68 has a head plug screwed into the distributor head so as to be in close contact with the top of the plunger barrel 16 as shown in a second embodiment described later. Is formed between

The left end of the plunger 6 is connected to the right end of the drive unit 4 via a cam mechanism 5, and the plunger 6 is configured to reciprocate in accordance with the rotation of the drive shaft 4. The cam mechanism 5 includes a cam disk connected to the plunger 6 by a pin.
41, a roller holder assembly 42 having a plurality of rollers 44 for supporting the cam disk 41, and a spring assembly 45 for urging the cam disk 41 and bringing the cam surface into contact with the rollers 44. These mechanisms will be described in detail in a second embodiment.

The plunger 6 has a plurality of inlet slits 80 corresponding to the number of cylinders of the engine on the outer periphery of the end, a center hole 83 is formed in the axial direction from the top surface, and the end of the center hole 83 is formed by the plunger barrel 16. The cut-off port 84 is opened before the enclosed area. The cutoff port 84 is controlled to be opened and closed by a control sleeve 12a which is slidably fitted to the plunger 6 as described later, thereby adjusting the fuel injection amount. In addition, a single outlet slit 86 is provided in the middle outer periphery of the plunger 6 and connected to the middle of the center hole 83 via a bypass, and a pressure equalizing slit 85 is provided at a position displaced in the circumferential direction with the outlet slit 86. Is provided.

When the cam disk 41 and the plunger spring move down the plunger 6 to match the inlet port 67 of the plunger barrel 16, fuel oil is sucked from the supply passage 66 into the fuel pressurizing chamber 68 through the pump chamber 9. . At the same time, the vertical holes 83 are filled. Then, the fuel is pressurized in the injection stroke in which the plunger 6 rotates while being raised, and when the outlet slit 86 meets one of the outlet ports 71 for the number of cylinders provided in the plunger barrel 16, the fuel is pressurized. Is fed from the discharge passage 70 through the delivery valve 11 to an injection nozzle (not shown). Then, after the injection is completed, when the plunger 6 rotates 180 degrees, the outlet port 71 meets the equalizing slit 85,
As a result, the discharge passage 70 communicates with the pump chamber 9 and the discharge passage 70
The pressure of the fuel inside is reduced to the same pressure as the pump chamber pressure.

A solenoid valve 8 for fuel cut is provided in the middle of the supply passage 66 so as to close the supply passage 66 when the engine is stopped.

The control sleeve 12a is controlled by an electric governor 12 arranged in the cover 1b. That is, the electric governor 12 includes the coil 12b and the core 12c.
And a rotor 12d.The rotor 12d has a shaft 12e and a ball 1.
It is connected to the control sleeve 12a via 2f.
Therefore, the rotor is controlled by energizing the coil.
The change in the rotation angle of 12b controls the position of the coat roll sleeve 12a, thereby changing the effective stroke of the plunger 6.

A timer 2 is provided below the body 1a as means for controlling the injection timing. The timer 2 has a cylindrical timer piston chamber 2a and a timer piston 2b slidably inserted therein. The timer piston 2b has an intermediate portion connected to the holder 43 of the roller holder assembly 42 by a pin 2c. Have been.

The timer piston chamber 2a is a low-pressure chamber 21 in which a spring 2d for urging the timer piston 2b right and left is disposed on the left end side. The low-pressure chamber 21 is connected to a suction side of a feed pump 23 by a low-pressure passage 22. Have been. The right end side of the timer piston chamber 2a is a high-pressure chamber 20. In FIG. 1, for convenience of explanation, the timer 2 is shown in an expanded state of 90 degrees, but in actuality, the timer piston chamber 2a and the timer piston 2b are perpendicular to the plane of the drawing. FIG. 2 shows this actual state. In FIG. 2, connecting means such as pins are omitted.

In FIGS. 1 and 2, reference numeral 3 denotes a timer piston 2.
It is an electromagnetic timing control valve that adjusts the fuel injection timing in cooperation with. In this embodiment, the timing control valve 3 is inserted into a hole 1d provided below the body 1a, and is slidably disposed in a valve body 3e having a side hole 3f and a tip hole 3g, and a valve body 3e. Needle 3a and a spring 3b that urges the needle 3a to close the tip hole 3g
And an electromagnetic unit 3c that opens the needle 3a against the spring 3b when energized.

In the hole 1d where the timing control valve 3 is mounted, a high pressure groove 30 is provided in an intermediate portion corresponding to the side hole 3f.
However, low-pressure holes 31 are formed in portions corresponding to the tip holes 3g, respectively. The high-pressure groove 30 communicates with the high-pressure chamber 20 of the timer piston chamber 2a through a passage 35, and the low-pressure hole 31 communicates with the low-pressure chamber 21 of the timer piston chamber 2a through a low-pressure passage 32.

The electromagnetic unit 3c is electrically connected to the electronic control unit 13. The electronic control unit 13 calculates signals from a load sensor, an engine speed sensor (engaging gear plate) 37, a fuel temperature sensor 36, and the like, and the electromagnetic unit 3c is operated at a desired duty ratio control by a command based on the signals. It has become so. The electronic control device 13 is also electrically connected to the electric governor 12 and the solenoid valve 8, and controls the operation thereof.

In the above-described structure, conventionally, the pump chamber 9 and the timer piston high-pressure chamber 20 communicate with each other by an orifice formed in the timer piston 2b itself and a port.
That is, the pump chamber 9 and the high pressure groove 30 of the timing control valve 3 are connected via the timer piston 2b.

The feature of the present invention is that this orifice and port are abolished,
The purpose is to make the pump chamber 9 and the high-pressure groove 30 of the timing control valve 3 directly communicate with each other by a passage 33 passing through the pump housing 1. And this passage 33
Is provided with a fixed orifice 34 for reducing the influence of the pulsation of the control oil pressure (pump chamber oil pressure) on the high-pressure groove 30. It is preferable that the fixed orifice 34 is provided at the bottom of the body 1a from the surface of processing or the like. The specific mode will be described later.

The connection port of the passage 33 to the high pressure groove 30 is located at a position displaced in the circumferential direction from the connection port of the passage 35 to the timer piston high pressure chamber 20.

FIG. 3 shows a second embodiment of the present invention. In this embodiment, the timing control valve 3 is attached to a block 7 for a valve holder, which is separate from the body 1a, and the block 7 is connected to the body 1a by bolts (not shown).
Therefore, the hole 1d, the high pressure groove 30, and the low pressure hole 31 are provided in the block 7 in this case. The passage 33 is formed from the body 1a to the block 7, and the passage 35 is formed in the block 7. In this embodiment, an external pipe is used for the low-pressure passage 32, but it is needless to say that the low-pressure passage 32 may be an internal passage.

FIGS. 4a, 4b and 4c show embodiments of the fixed orifice 34 applied to the first and second embodiments and a third embodiment described later. FIG. 4a shows the bottom wall of the body 1a with holes formed therein. FIG. 4b shows a case where a stepped hole 340 is formed in the bottom wall of the body 1a, a fine hole is formed from the bottom, and a filter 341 is attached to the stepped hole 340. FIG. 4c shows the pore 343
A chip 342 having the following structure is formed separately, and this is fitted into a stepped hole 340 formed in the bottom wall of the body 1a by press-fitting, screwing, or the like, and fixed.

5 to 8 show a third embodiment of the present invention.

While the pump chamber 9 of the first and second embodiments is formed over the entire area inside the body 1a, in this embodiment, only a certain partitioned area is formed in the annular pump chamber 9.
(The others are of the type that accommodates lubricating oil). The invention also applies to a distribution fuel injection pump of this type, in which the bottom of the annular pump chamber 9 and the high-pressure groove 30 of the timing control valve 3 are directly connected by a passage 33 having a fixed orifice 34.

This embodiment has an advantage that the user who does not know that the fuel (light oil) also serves as the lubricating oil can satisfactorily lubricate the cam mechanism 5 even when using light oil such as kerosene instead of light oil. . That is, when light oil is accidentally put into the housing, lubrication of the cam mechanism 5 becomes insufficient,
Surface separation occurs between the roller and the disc cam that are in strong contact with the spring, and the separated chips inhibit the movement of the mechanism in the body. According to this embodiment, such a problem can be solved.

The major difference between the third embodiment and the first embodiment is that
In the body 1a, the annular pump chamber 9 and the cam chamber 14 are defined by using a spring assembly 45 for the cam mechanism 5, the lubricating oil is stored in the cam chamber 14, and the annular cam chamber 14 is detoured around the cam chamber 14. The point is that fuel is supplied to the pump chamber 9 from the feed pump 23.

More specifically, the feed pump 23 is separated from the cam chamber 14 by a shielding plate 25. The cam chamber 14 has an inlet port 18a and an outlet port 18b opened as shown in FIG. The engine oil circulation system is connected.

On the other hand, a suction passage 24 and a suction port 23a are formed in the body 1a on the left side of the feed pump 23, and fuel is supplied from an external fuel tank to the feed pump 23 through the suction passage 24 and the suction port 23a. Discharge port
23b is a fuel supply passage 6 formed between the body 1a and the cover 1b.
It is connected to the annular pump 9 via 0. Fuel supply path 6
0 has a passage 61 extending substantially in the radial direction of the body 1a and bent passages 62 and 63 formed in the cover 1b, as shown in FIG. Recess 101 formed
And a cover 1b. The fuel reservoir 64 communicates with the annular pump chamber 9 through a filter-provided through hole 65 formed at the bottom of the fuel reservoir 64.
The path from the annular pump chamber 9 to the fuel pressurizing chamber 68 is the same as in the first embodiment. The passages 61, 62, 63 and the fuel reservoir 64 are O
The outside and the cam chamber 14 are oil-tightly shut off by the rings 69a and 69b.

The annular pump chamber 9 is formed using a spring seat 47 as a component of the spring assembly 45. Specifically, the spring assembly 45 includes two spring seats 4.
7, 48, a spring 46a, 46b concentrically arranged between the spring seats 47, 48, and a locking ring 49 fixed to the spring seat 47.

The end face of the spring seat 47 is in contact with the end face of the distributor head 1c via an O-ring 55, and is fixed by screws 50. The spring seat 47 is not a flat plate but has a tubular portion 47a which is formed in a trumpet shape on the outer peripheral side so as to obtain a predetermined clearance between the spring seat 47 and the body 1a. The axial end of the cylindrical portion 47a forms a straight cylindrical enlarged portion 47b, and the inner peripheral surface of the body 1a has an O.
It is close through a ring 56. The annular pump chamber 9 is formed by these configurations.

The locking ring 49 is a member for assembling the spring assembly 45, and is fixed to the axial end 47b of the cylindrical portion 47a with a screw. Therefore, the outer peripheral edge of the spring seat 48 is separated from the locking ring 49, and the inner peripheral side is locked to the large-diameter portion 6a at the left end of the plunger via a bearing washer and an adjustment shim, and the spring force of the springs 46a and 46b is adjusted. Plunger 6
To communicate.

The third embodiment also differs from the first embodiment in that a control sleeve is not used as a means for controlling the injection amount and a spill solenoid valve 120 is used as shown in FIG. Specifically, the spill solenoid valve 120 has a poppet valve 121,
The distal end including this is inserted and fixed in a concave portion 102 formed on the side of the distributor head 1c. An annular groove 90 is formed at the bottom of the concave portion 102, and the annular groove 90 communicates with the fuel pressurizing chamber 68 via a not-shown spill passage formed in the distributor head 1c and the plunger barrel 16. .

A plunger barrel 16 is provided at the center of the bottom of the concave portion 102.
A spill chamber 91 is formed which is closed, and this spill chamber 91 communicates with the annular pump chamber 9 or the supply passage 66 through a passage (not shown) formed in the plunger barrel 16.

In this embodiment, in the outward stroke of the plunger 6, the poppet valve 121 of the spill solenoid valve 120 closes the passage hole 122 in the solenoid valve, so that the fuel pressurizing chamber 68 and the fuel supply passage 60 are shut off. You. Therefore, the fuel is pressurized in the fuel pressurizing chamber 68, and is injected from the injection nozzle through the outlet port 71, the discharge passage 70, and the delivery valve 11. Next, when the electromagnetic unit (not shown) of the spill solenoid valve 120 is energized, the poppet valve 121 opens, whereby the fuel in the fuel pressurizing chamber 68 passes through the annular groove 90, the spill chamber 91, and the not-shown passage. The fuel is released to the annular pump chamber 9 or the supply passage 66 via the fuel supply passage, and the fuel injection ends.

A leak stopper groove 82 is formed between the peripheral surface of the plunger 6 and the plunger barrel 16, and the leak stopper groove 82 is formed through leak passages 73 and 74 formed in the plunger barrel 16 and the distributor head 1c, respectively. To a fuel tank (not shown). A small amount of pressurized fuel in the fuel pressurizing chamber 68 flows in the direction of the cam chamber 14 through a sliding gap between the peripheral surface of the plunger 6 and the plunger barrel 16, although the amount is small. Insert this into the leak stopper groove 82
Can be accommodated and returned to the fuel tank.

In this embodiment, the plunger barrel 16 is formed with an annular groove 76 partially communicating with the equalizing port 75, and the distributor head 1c has an equalizing passage having one end connected to the annular groove 76.
77 is formed, and this pressure equalizing passage 77 is connected to the annular pump chamber 9. Therefore, when the plunger 6 is at the predetermined stroke and rotation angle position, the equalizing slit 85 connects the equalizing port 75 and the discharge passage 70, and makes the residual pressure in the discharge passage 70 equal to the fuel supply pressure.

The pressure equalizing port 75 is connected to a leak passage 78 opened in the end face of the plunger barrel 16, and the leak passage 78
Is connected to the outer peripheral side of the edge of the head plug 17 which achieves the ceiling side of the fuel pressurizing chamber 68, and leaked fuel accumulated in this portion is annularly leaked from the leak passage 78 through the equalizing port 75, the annular groove 76, the equalizing passage 77. The pump chamber 9 is returned.

The large diameter portion 6a of the plunger 6 has a notch, and the pin 330 is inserted into the notch and a hole formed in the cam disk 41, whereby the plunger 6 and the cam disk 41 are rotated integrally. Further, the cam disk 41 has a coupler portion 41a having a non-circular cross-sectional shape in the axial direction, and the coupler portion 41a is provided on the inner protrusion 4a of the drive shaft 4.
And relative axial movement.

The structures of the timer 2 and the timing control valve 3 are the same as those of the first and second embodiments. Further, the low pressure chamber 21 of the timer 2 is connected to the suction passage 24 of the feed pump 23 via the low pressure passage 22, and the low pressure chamber 21 and the low pressure passage 32 connect the high pressure chamber 20 to the low pressure hole of the timing control valve 3.
31, the high-pressure chamber 21 communicates with the high-pressure groove 30 of the timing control valve 3, the high-pressure groove 30 communicates directly with the annular pump chamber 9 via the fixed orifice 34, and the fixed orifice 34 can also take the forms of FIGS. 4a to 4c.
Is the same as

[Operation of the embodiment]

 Next, the operation and operation of the embodiment will be described.

In the first embodiment, the flow rate of the fuel oil in the pump chamber 9 is reduced by the fixed orifice 34 provided in the body 1a of the pump housing 1 and flows into the high-pressure groove 30 of the timing control valve 36 through the passage 33. Then, it flows into the high-pressure chamber 20 of the timer 2 through the passage 35.

When the electromagnetic portion 3c of the timing control valve 3 is not energized, the needle 3a is open and the high-pressure groove 30 and the low-pressure hole 31 are shielded, so that the high-pressure chamber 20 and the low-pressure chamber 21 of the timer 2 are shut off. Have been.

The pressure in the pump chamber 9 depends on the engine speed, that is, the oil feed pressure of the feed pump 23. When the speed is low, the pressure in the high-pressure chamber 20 is also low. Pressed to the 20 side. That is, it is located on the retard side. When the engine speed increases and the pressure in the high-pressure chamber 20 exceeds the set force of the spring 2d, the timer piston 2b moves to the low-pressure chamber side, whereby the roller holder assembly 42 rotates via the pin 2c. Thereby, the lift position of the cam disk 41 is advanced, and the ignition delay time is corrected.

In such a situation, when the electromagnetic portion 3c of the timing control valve 3 is energized, the needle 3a is lifted and opened, whereby the high-pressure groove 30 is opened inside the side hole 3f, between the valve body 3e and the needle valve 3a. It communicates with the low pressure hole 31 through the passage and the tip hole 3g. Therefore, the high pressure chamber 20 of the timer 2
Is leaked to the low-pressure chamber 21 through the passage 35, the low-pressure hole 31, and the low-pressure passage 32, and the pressure in the high-pressure chamber 20 decreases.

As a result, the timer piston 2b is positioned at a position where the adjusted pressure and the spring 2d are balanced, and this movement is transmitted to the roll holder assembly via the pin 2c and rotates. Accordingly, by turning on / off the energization of the electromagnetic unit 3 at a desired detail ratio by the electronic control unit 13, the angular position of the roller holder assembly 42 is adjusted, and the cam profile use area of the cam disc 41 at the fuel injection timing is controlled. The injection timing is adjusted to the operating condition.

In such control, the operating pressure for actually moving the timer piston 2b is, as described above, the pressure Pt of the high-pressure chamber 20.
₂ In the present invention, the hydraulic path from the pump chamber 9 to the high-pressure chamber 20 is constituted by the pump chamber 9-the fixed orifice 34 of the pump housing-the passage 33-the high-pressure groove 30-the passage 35, as shown in FIG. Therefore, the dead volume V ₁ of the fixed orifice valve seat portion of the timing control valve 3 to (the boundary between the high pressure and low pressure) are compared in the dead volume V ₂ of the conventional system of Figure 11, significantly reduced.

As a result, the amount of work required to change the operating pressure of the timer piston 2b can be reduced accordingly.
Therefore, the responsiveness of the timer piston 2b is improved,
Timing control that makes full use of the features of the electronic control format can be realized.

The above operation and action are exactly the same in the third embodiment except that the pump chamber is annular. Explaining the specific operation and function of the third embodiment, a lubricating oil (engine oil) is stored in the lower part of the cam chamber 14, and the lubricating oil is scattered by the cam disk 41 rotating at high speed. Lubricate the contact portion between the cam surface and each roll 7a. Also, lubrication between the plunger 6 and the plunger barrel 16 is performed.

On the other hand, the fuel oil discharged from the feed pump 23 is sent to the passage 61 → bent passages 62, 63 → the fuel reservoir 64, where the pulsation is absorbed by the fuel reservoir 64, and the annular pump 9.

〔The invention's effect〕

According to the above-described claim 1 of the present invention, in the distribution type fuel injection pump including the electronic control type timer,
The high pressure groove 30 of the timing control valve 3 and the high pressure chamber 20 of the timer piston are connected by a passage 35, and the pump chamber 9 and the high pressure groove 30 are connected to the timer piston 2b.
, But directly through the passage 33 through the fixed orifice 34 provided in the pump housing, it is possible to reduce the dynamic dead volume of the hydraulic path for timer control, thereby improving the responsiveness, An excellent effect that the control performance of the timer piston can be improved can be obtained.

Further, according to claim 2 of the present invention, the pump chamber 9
Is separated from the remaining cam chamber 14, and the cam chamber 14 contains lubricating oil independently of fuel to lubricate the cam mechanism. An excellent effect is obtained that troubles are avoided and good lubrication can always be performed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing a first embodiment of the present invention, FIG. 2 is a transverse cross-sectional view of the lower part of the body in FIG. 1, and FIG. 3 is a partial cross-sectional view showing a second embodiment of the present invention. 4a to 4c are sectional views showing an embodiment of a fixed orifice in the present invention, FIG. 5 is a cross-sectional side view showing a third embodiment of the present invention,
FIG. 6 is a sectional view showing the relationship between the timer and the roller holder assembly in the third embodiment, FIG. 7 is a partial sectional view showing the inflow and outflow of lubricating oil in the third embodiment, and FIG. 8 is a solenoid valve for spill. FIG. 9 is a partial sectional view of a conventional pump, FIG. 9 is a partial sectional view of a conventional pump, and FIG. 11 is a partial sectional view of a conventional pump. 1 ... pump housing, 1a ... body, 1b ... cover, 1c ... distributor head, 2 ... timer,
2b: timer piston, 3: timing control valve, 3c: electromagnetic part, 6: plunger, 9: pump chamber (annular pump chamber), 20: high-pressure chamber of timer piston, 21: timer piston Low pressure chamber, 30 High pressure groove, 31 Low pressure hole, 32 Low pressure passage, 33 Passage, 34
... fixed orifice, 35 ... passage

Continued on the front page (56) References JP-A-54-163224 (JP, A) JP-A-57-63931 (JP, U) JP-A-59-130039 (JP, U) JP-A-61-47444 (JP) , U) Actually open 58-132140 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02D 1/18

Claims (2)

(57) [Claims] 1. A plunger 6 having a pump chamber 9 therein and rotatable and reciprocally movable in accordance with rotation of an engine.
A timer piston 2b for moving a roller holder assembly 42, and a high-pressure chamber 20 and a low-pressure chamber 21 on both axial sides of the timer piston 2b
An electromagnetic timing control valve 3 for communicating and shutting off the high pressure groove 30. The timing control valve 3 has a high pressure groove 30 at the high pressure side fuel inlet, and a low pressure passage at a position displaced from the high pressure groove 30. 32
Has a low-pressure hole 31 communicating with the timer piston low-pressure chamber 21 through, the high-pressure groove 30 and the low-pressure hole 31 are communicated or blocked by opening and closing a valve operated by the electromagnetic unit 3c, In the fuel injection pump of the type in which the timer piston 2b is moved by controlling the duty of the electromagnetic unit 3 to control the fuel injection timing, the high pressure groove 30 of the timing control valve 3
And the high pressure groove 30 and the high pressure chamber 30 are connected by a passage 35, and the high pressure groove 30 and the pump chamber 9 are directly connected by another passage 33 having a fixed orifice 34. 2. A pump chamber 9 is formed into an annular shape by an inner wall of a pump housing and a cylindrical spring seat 47 forming a part of a plunger spring assembly. The annular pump chamber 9 is a remaining space inside the pump housing. 2. The annular pump chamber 9 is oil-tightly shut off from the cam chamber 14, and the annular pump chamber 9 includes fuel supplied from a feed pump 23 by a fuel supply path bypassing the cam chamber 14. Distribution type fuel injection pump.