JPH02140433A - Distributing type fuel injection pump - Google Patents

Abstract

PURPOSE:To improve responsibility by communicating the high pressure group of a timing control valve with the upstream side of a timer piston high pressure chamber, and directly connecting the high pressure group and a pump room through a fixed orifice. CONSTITUTION:The flow of fuel oil in a pump room 9 is throttled down with a fixed orifice 34 of a pump housing 1, flows into the high pressure group 30 of a timing control valve 3 through a passage 35, then into the high pressure chamber 20 of a timer 2 through a passage 33. If electricity is turned on to the solenoid part 3c of the timing control valve, a needle valve 3a is opened to communicate the high pressure group 30 and a low pressure hole 31, and the pressure from the high pressure chamber 20 of the timer 2 is leaked into the low pressure chamber 21 through a passage 35, the low pressure hole 31 and a low pressure passage, which determines the position of a timer piston 2b in balance with a spring 21 to change the timing. The responsibility of the timer piston is thus improved to raise injection timing control performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a distribution type fuel injection pump, and particularly to a type of distribution type fuel injection pump in which injection timing is electronically controlled.

[Conventional technology and its technical issues]

A type of distributed fuel injection pump used in diesel engines that controls injection timing by moving a timer piston by controlling the duty of a timing control valve is disclosed in Japanese Patent Laid-Open No. 57-970.
This is conventionally known as shown in Publication No. 24 and the like.

In this type of timer, as shown in FIG. 10, a timer piston chamber 2a is formed in the housing, and a timer piston 2b is slidably inserted therein to partition a high pressure chamber 2o and a low pressure chamber 21 on both sides. A timing control valve 3 operated by a solenoid valve is installed at the end of the housing. The high pressure chamber 2o is communicated with the pump chamber 9 through an orifice 200 and a boat 201 bored in the timer screw 1 hem 2b itself, and the side of the high pressure chamber 20 is connected to the high pressure group 30 of the timing control valve 3 through a boat 300. there was. In addition, a spring 2 is provided in the low pressure chamber 21 to constantly bias the timer piston 2b toward the high pressure chamber.
d, and its low pressure chamber 21 was 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, the pump chamber pressure PL
On the other hand, the timer piston control hydraulic pressure path is configured with the orifice 200 bored in the timer piston as the boundary, and the fuel oil in the pump chamber 9 is routed from the orifice 200 to the port 201 to
The high pressure chamber 20 flows into the high pressure group 3o of the timing control valve 3 via the port 300.

In the hydraulic path, the orifice 200 is connected to the pump chamber 9
It is thought that a part of it is separated. It is clear that the smaller the dead volume of this separated portion, the better the timing control performance.

In the conventional path, when viewed dynamically, it is the pressure in the high pressure chamber 20 that actually moves the timer piston 2b, so the dead volume 2 increases by the boat 201.300. As a result, the pressure P in the high pressure chamber 20 is reduced by the leak control of the timing control valve 3.
The amount of work required to change t2 increases. In other words, there is a problem in that the amount of work required to change the operating pressure of the timer piston 2b increases and the responsiveness of injection timing control decreases.

The basic object of the present invention is to reduce the dead volume of the timer control hydraulic pressure path as described above with a relatively simple structure, thereby improving the responsiveness of the electronically controlled timer piston, and controlling the injection timing timing. An object of the present invention is to provide a distributed fuel injection pump that can improve performance.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a timer piston for moving a roller holder assembly, and a high pressure chamber on both sides of the timer piston in the axial direction. In a fuel injection pump equipped with an electromagnetic timing control valve that communicates with and shuts off a low-pressure chamber, the high-pressure group of the timing control valve and the upstream side of the high-pressure chamber of the timer piston are communicated through a passage, and the pump housing The pump chamber and the high pressure group are directly connected by a passage through a fixed orifice.

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

Specifically, the latter is as follows. That is,
A pump chamber is defined in an annular manner by an inner wall of the pump housing and a cylindrical spring seat that constitutes a part of the plunger spring assembly, and the annular pump chamber receives fuel from the feed pump by a fuel supply passage that bypasses the cam chamber. It is designed to be supplied with air and is oil-tightly isolated from the cam chamber, which is the remaining space inside the pump housing.

The fixed orifice may be a small-diameter hole drilled directly into the wall of the pump housing, or it may be made as a chip-like part with a thin hole that is fitted into a hole in the pump bouncing wall. It's okay to be hit.

[For production]

In the present invention, the fuel oil in the pump chamber is throttled in flow through a fixed orifice provided in the pump housing, flows through a passage into a high pressure group of a timing control valve, and from there flows through a passage into a high pressure chamber of a timer.

When the timing control valve ff1m section is energized, the needle valve opens and the high pressure group and low pressure hole communicate with each other, so the pressure Pt1 in the high pressure chamber of the timer leaks to the low pressure chamber via the passage, the low pressure hole, and the low pressure passage. The pressure Pt2 in the high pressure chamber decreases. This causes the timer piston to
The adjusted pressure and the spring are positioned at a balanced position. Therefore, the angular position of the roller holder assembly is adjusted by turning on and off the energization of the electromagnetic section at a desired duty ratio using the electronic control device.
You can change the timing freely.

In such control, the operating pressure that actually moves the timer piston is the pressure PL2 in the high pressure chamber, but in the present invention, the hydraulic path from the pump chamber to the high pressure chamber is connected to the pump chamber - the fixed orifice of the pump housing - the passage - High pressure group - consists of passages. Therefore, the dead volume V□ from the pump chamber to the valve seat portion (boundary between high pressure and low pressure) of the timing control valve becomes significantly small. As a result, the amount of work required to change the operating pressure of the timer piston is reduced accordingly.
Therefore, the responsiveness of the timer piston is also improved.

〔Example〕

FIG. 1 shows a first embodiment of the invention. In FIG. 1, 1 is a pump housing, and a hollow body 1
a, and a cover 1b fixed to the upper opening of the body 1a.
and a distributor head IC that closes an opening on the right end side of the body 1a, and a pump chamber 9 is formed within the body. 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 the pump chamber 9 inside the body from the left end side of the body 1a, and connected to the engine crankshaft via a reduction gear (not shown) to the protrusion outside the body. be moved. A feed pump 2 is coaxially arranged at the left end of the pump chamber of the drive shaft 4.
3 is arranged, and fuel oil introduced from an external tank is supplied to the pump chamber 9 via a regulating valve 800. The regulating valve 800 has a function of reducing changes in the pump chamber pressure in the normal rotation range.

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

The left end of the plunger 6 is connected to the right end of the drive shaft 4 via a cam mechanism 5, and the plunger 6 is configured to rotate and reciprocate as the drive shaft 4 rotates. The cam mechanism 5 includes a cam disk 4 connected to the plunger 6 through a pin.
1 and a plurality of rollers 44 that support the cam disc 41.
and a spring assembly 45 that biases the cam disk 41 and brings the cam surface into contact with the roller 44.

These mechanisms will be explained in detail in the second embodiment.

The plunger 6 is provided with a plurality of inlet slits 80 corresponding to the number of cylinders of the engine on the outer periphery of the end, and a center hole 83 is bored in the axial direction from the top surface.
A cut-off port 84 is opened at the end of the plunger barrel 16 beyond the area surrounded by the plunger barrel 16. As will be described later, this cutoff port 84 is controlled to open and close by a control sleeve 12a that is slidably fitted onto the plunger 6, thereby adjusting the fuel injection amount.

Further, a center hole 8 is provided on the intermediate outer periphery of the plunger 6.
A single outlet slit 86 is provided which is connected to the middle of the outlet slit 3 via a side passage, and a pressure equalizing slit 85 is provided at a position displaced from this in the circumferential direction.

When the plunger 6 matches the inlet port 67 of the plunger barrel 16 during the downward stroke of the cam disk 41 and the plunger spring, fuel oil is sucked into the fuel pressurizing chamber 68 from the supply passage 66 communicating with the pump chamber 9. At the same time, the vertical hole 83 is also filled. Then, during the injection stroke in which the plunger 6 rotates while rising, the fuel is pressurized, and the outlet slit 86 opens into the plunger barrel 1.
Outlet ports 71 for the number of cylinders provided in G
When the pressurized fuel encounters one of the two, the pressurized fuel is forced to be sent from the discharge passage 70 via the delivery valve 11 to an injection nozzle (not shown). After the injection is completed, when the plunger 6 rotates 180 degrees, the outlet boat 71 encounters the pressure equalizing slit 85, so that the discharge passage 70 communicates with the pump chamber 9, and the pressure of the fuel in the discharge passage 70 is the same as the pump chamber pressure. lowered to pressure.

A solenoid valve 8 for fuel cut is provided in the middle of the supply passage 66, and the supply passage 66 is closed when the engine is stopped.
It is designed to block the

The control sleeve 2a is controlled by an electric governor 12 located inside the cover 1b. That is, the electric governor 12
The rotor 12d is connected to the control sleeve 12a via a shaft 12e and a ball 12f. Therefore, the position of the coat roll sleeve 12a is controlled by changing the rotation angle of the rotor 12b by controlling the energization of the coil.
This changes the effective stroke of the plunger 6.

A timer 2 is provided at the bottom of the body 1a as a means for controlling injection timing. Timer 2 is.

It has a cylindrical timer piston chamber 2a and a timer piston 2b slidably inserted into the cylindrical timer piston chamber 2a, and the timer piston 2b has an intermediate portion connected to a holder 43 of a roller holder assembly 42 by a pin 2c.

The timer piston chamber 2a has a timer piston 2b on the left end side.
The low pressure chamber 21 is equipped with a spring 2d that biases the
The low pressure chamber 21 is connected to the suction side of the feed pump 23 through a low pressure passage 22. Also,
The right end side of the timer piston chamber 2a is a high pressure chamber 20. In FIG. 1, for convenience of explanation, timer 2 is set to 9.
Although shown in a 0 degree expanded state, the timer piston chamber 2a and the timer piston 2b are actually perpendicular to the plane of the paper. FIG. 2 shows this actual situation. In FIG. 2, connecting means such as bottles are omitted.

In FIGS. 1 and 2, reference numeral 3 designates an electromagnetic timing control valve that cooperates with the timer piston 2 to adjust the fuel injection timing. In this embodiment, the timing control valve 3 is inserted into a hole 1d provided at the bottom of the body 1a, and is slidable into a valve body 3e having a side hole 3f and a tip hole 3g. The needle 3a is disposed in the needle 3a, the spring 3b biases the needle 3a and closes the tip hole 3g, and the electromagnetic part 3C opens the needle 3a against the spring 3b when energized.

In the hole 1d where the timing control valve 3 is installed, there is a high pressure group 30 in the middle part corresponding to the side hole 3f.
However, low-pressure holes 31 are formed at locations corresponding to the tip holes 3g. The high pressure group 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 high pressure chamber 20 of the timer piston chamber 2a through a passage 32.
It communicates with the low pressure chamber 21 of a.

The electromagnetic section 3c is electrically connected to the electronic control device 13. This electronic control device 13 calculates signals from the load sensor, engine speed sensor (sensing gear plate) 37, fuel temperature sensor 36, etc., and based on the commands, the electromagnetic section 3c is operated with desired duty ratio control. It looks like this. The electronic groove device 13 is also electrically connected to the electric governor 12 and the cut solenoid 8 to control their operations.

In the above structure, conventionally, the pump hole 9 and the timer piston high pressure chamber 20 were communicated through an orifice and a port bored in the timer screw 1-2b itself. In other words, the pump chamber 9 and the high pressure group 30 of the timing control valve 3 are connected via the timer piston 2b.

A feature of the invention is that this orifice and port are eliminated, and the pump chamber 9 and the high-pressure group 30 of the timing control valve 3 are in direct communication by a passage 33 passing through the pump housing 1. A part of this passage 33 is provided with a control hydraulic pressure (
A fixed orifice 34 is provided to reduce the effects of pulsations in the pump chamber oil pressure. The fixed orifice 34 is.

From the viewpoint of processing, etc., it is preferable to provide it at the bottom of the body 1a. Specific aspects thereof will be described later.

Note that the connection port of the passage 33 to the high pressure group 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 invention. In this embodiment, the timing control valve 3 is attached to the body 1a and a separate block 7 for a valve holder, and the block 7 is connected to the body 1a by a bolt (not shown). Therefore, hole 1d and high pressure group 30. Low pressure hole 31
is provided in block 7 in this case. The passage 33 is bored from the body 1a to the block 7, and the passage 35
is drilled in block 7. Although an external pipe is used as the low pressure passage 32 in this embodiment, it goes without saying that the present invention is not limited to this and an internal passage may be used.

Figures 4a, 4b, and 4c show a fixed orifice 34 applied to the first and second embodiments as well as a third embodiment to be described later.
This shows the aspect of FIG. 4a shows pores formed in the bottom wall of body a.

In FIG. 4b, a stepped hole 340 is made in the bottom wall of the body 1a, a small hole is made from the bottom of the hole, and a filter 341 is attached to the stepped hole 340. FIG. 4c shows the pore 34
Separately make a chip 342 having 3 and attach it to the body 1a.
It is fitted and fixed by press-fitting, screwing, etc. into a stepped hole 340 bored in the bottom wall of the.

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

While the pump chamber 9 in the first and second embodiments was formed over the entire area within the body 1a, in this embodiment, only the partitioned area formed by the annular pump chamber 9 (
Others are of the type that contain lubricating oil). The invention also applies to this type of distributed fuel injection pump, in which the bottom of the annular pump chamber 9 and the high-pressure group 30 of the timing control valve 3 are directly connected by a passage 33 with a fixed orifice 34.

This embodiment has the advantage that the cam mechanism 5 can be well lubricated even when a user who does not know that fuel (light oil) also serves as a lubricating oil uses light oil such as kerosene instead of light oil. . In other words, if light oil is accidentally put into the housing, the cam mechanism 5 will not have enough lubrication, and the surface of the roller and disc cam, which are in strong contact with each other due to the spring, will peel off, and the peeled chips will cause damage. Movement of mechanisms within the body is inhibited. According to this embodiment, this problem can be solved.

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

To explain in detail, the feed pump 23 is separated from the cam chamber 14 by a shielding plate 25, and the cam chamber 14 has a seventh
As shown in the figure, an inlet port 18a and an outlet port 18b are open, and an engine oil circulation system is connected to these via an eye bolt (not shown).

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 via the suction passage 24 and suction port 23a, and the feed pump 2
The third discharge boat 23b is connected to the annular pump chamber 9 via a fuel supply passage 6o formed between the body 1a and the cover 1b. As shown in FIG. 5, the fuel supply passage 60 includes a passage 61 extending substantially in the radial direction of the body 1a, and a cover lb.
The passageway 6 has a bent passageway 62,63 formed in the
3 communicates with a fuel reservoir chamber 64 formed by the recess 101 formed in the body 1a and the cover 1b. The fuel reservoir chamber 64 communicates with the annular pump chamber 9 through a filtered through hole 65 formed at the bottom of the fuel reservoir chamber 64 . The route 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 chamber 64 are oil-tightly sealed off from the outside and the cam chamber 14 by O-rings 69a, 69b.

The annular pump chamber 9 is formed using a spring seat 47 as a part of a spring assembly 45. Specifically, the spring assembly 45 includes two spring seats 47.48, springs 46a and 46b arranged concentrically between the spring seats 47.48, and a locking ring 49 fixed to the spring seats 47. We are prepared.

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

The locking ring 49 is a member for assembling the spring assembly 45, and is fixed to the axial end portion 47b of the cylindrical portion 47a with a screw.

Therefore, the outer peripheral edge of the spring seat 48 is spaced apart 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 the bearing washer and adjustment shim, and the spring force of the springs 46a, 46b is is transmitted to the plunger 6.

The third embodiment also differs from the first embodiment in that a control sleeve is not used as the injection amount control means, but a spill electromagnetic valve 120 is used as shown in FIG. To be more specific, the spill solenoid valve 120 has a poppet valve 121, and the tip including the poppet valve 121 is connected to the distributor head I.
It is inserted and fixed into a recess 102 formed on the side of C.

An annular groove 90 is formed at the bottom of the recess 102, and this annular groove 90 communicates with the fuel pressurizing chamber 68 via a spill passage (not shown) formed in the distributor head IC and the plunger barrel 16.

Further, a plunger barrel 1 is provided at the center of the bottom of the recess 102.
6 forms a closed spill chamber 91, which communicates with the annular pump chamber 9 or the supply channel 66 through a passage (not shown) formed in the plunger barrel 16.

In this embodiment, during the forward stroke of the plunger 6, the poppet valve 121 of the spill solenoid valve 120 closes the passage hole 122 in the solenoid valve.

Therefore, the fuel pressurization chamber 68 and the fuel supply path 60 are cut off. Therefore, the fuel is pressurized in the fuel pressurizing chamber 68, and the outlet boat 71. It is injected from the injection nozzle via the discharge passage 70 and the delivery valve 11. Next, when the electromagnetic part (not shown) of the spill electromagnetic valve 120 is energized, the poppet valve 121 opens, thereby causing the fuel pressurization chamber 6 to open.
The fuel in the pump 8 escapes to the annular pump chamber 9 or the supply line 66 via the annular groove 90, the spill chamber 91, and a passage (not shown), and fuel injection ends.

Note that a leak stopper groove 82 is formed between the circumferential surface of the plunger 6 and the plunger barrel 16, and this leak stopper groove 82 is connected to the leak passage 7 formed in the plunger barrel 16 and the distributor head IC, respectively.
It is connected to a pipe (not shown) via 3.74 and leads to a fuel tank. Although the pressurized fuel in the fuel pressurizing chamber 68 is in a small amount, the circumferential surface of the plunger 6 and the plunger barrel 1
It flows in the direction of the cam chamber 14 through the sliding gap 6.

The leak stopper groove 82 accommodates this, allowing it to be returned to the fuel tank.

Further, in this embodiment, an annular groove 76 is formed in the plunger barrel 16, which partially communicates with the pressure equalizing boat 75, and a pressure equalizing passage 77, which has one end connected to the annular groove 76, is formed in the distributor head IC. A passage 77 is connected to the annular pump chamber 9 . Therefore, when the plunger 6 is at a predetermined stroke and rotational angle position, the pressure equalizing suline 1-85 communicates the pressure equalizing boat 75 with the discharge passage 70, and the residual pressure in the discharge passage 70 is made equal to the fuel supply pressure. do.

The pressure equalization boat 75 is connected to a leak passage 78 that is opened in the end face of the plunger barrel 16, and the leak passage 78 is connected to the outer peripheral edge of the head plug 17 that forms the ceiling side of the fuel pressurizing chamber 68. The leakage fuel accumulated in this part is transferred from the leakage passage 78 to the pressure equalization boat 75 and the annular groove 76.
, and is returned to the annular pump chamber 9 via a pressure equalization passage 77.

The large diameter portion 6a of the plunger 6 has a notch, and by inserting a pin 330 into a hole formed in the notch and the cam disk 41, the plunger 6 and the cam disk 41 are rotated together. Further, the cam disk 41 has a coupler portion 41a having a non-circular cross section in the axial direction, and the coupler portion 41a engages with the inner protrusion 4a of the driving shaft 4 by relative movement in the axial direction.

The structures of the timer 2 and timing control valve 3 are the same as in the first and second embodiments. Also, the low pressure chamber 21 of the timer 2 is connected to the feed pump 23 via the low pressure passage 22.
The low pressure chamber 2] is connected to the suction passage 24 of the timing control valve 3, and the high pressure chamber 20 is connected to the low pressure hole 31 of the timing control valve 3 through the low pressure passage 32.
is high pressure group 30 of timing control valve 3.
that the high pressure group 30 communicates directly with the annular pump chamber 9 via a fixed orifice 34, which is shown in FIGS. 48 to 4c.
The aspect of the figure and the scales are also the same as in Examples 1 and 2.

[Effect of the embodiment]

Next, the operation and effect of the embodiment will be explained.

In the first embodiment, the fuel oil in the pump chamber 9 is throttled in flow through a fixed orifice 34 provided in the body 1a of the pump housing 1, and flows into the high pressure group 30 of the timing control valve 36 through a passage 33. From there, it flows into the high pressure chamber 2o of the timer 2 through the passage 35.

When the electromagnetic part 3C of the timing control valve 3 is not energized, the needle 3a is closed, the high pressure group 30 and the low pressure hole 31 are cut off, and therefore the high pressure chamber 20 and the low pressure chamber 21 of the timer 2 are cut off. has been done.

The pressure in the pump chamber 9 depends on the rotational speed of the engine, that is, the oil feeding pressure of the feed pump 23.

When the rotational speed is low, the pressure in the high pressure chamber 20 is also low, so the timer piston 2b is pressed toward the high pressure chamber 20 by the set force of the spring 2d. In other words, it is located on the retard side. When the engine speed increases and the pressure in the high pressure chamber 2o exceeds the setting force of the spring 2d, the timer piston 2
b moves to the low pressure chamber side, thereby rotating the roller holder assembly 42 via the pin 2C. This advances the lift position of the disc cam 5 and corrects the ignition delay timing.

In this situation, if the electromagnetic part 3c of the timing control valve 3 is energized, the needle 3a will lift and open, and the high pressure group 30 will open the side hole 3f, the internal passage between the valve body 3e and the needle valve 3a. , communicates with the low pressure hole 31 via the tip hole 3g. Therefore, the pressure in the high pressure chamber 20 of the timer 2 leaks to the low pressure chamber 21 via the passage 35, the low pressure hole 31, and the low pressure passage 32, and the pressure in the high pressure chamber 20 descend.

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 roller holder assembly via the pin 2c, causing it to rotate once.

Therefore, by turning on and off the energization of the electromagnetic section 3 at a desired duty ratio by the electronic control device 13, the angular position of the roller holder assembly 42 is adjusted, and the cam profile usage range of the cam disc 41 at the fuel injection timing is controlled. The injection timing is adjusted to suit the operating conditions.

In such control, the operating pressure that actually moves the timer piston 2b is the pressure Pt2 in the high pressure chamber 20, as described above. In the present invention, the hydraulic path from the pump chamber 9 to the high pressure chamber 20 is composed of the pump chamber 9, the fixed orifice 34 of the pump housing, the passage 1833, the high pressure group 30, and the passage 35, as shown in FIG. Therefore, the dead volume □ from the fixed orifice to the valve seat portion (boundary between high pressure and low pressure) of the timing control valve 3 is significantly smaller than the dead volume v2 of the conventional system shown in FIG.

As a result, the amount of work required to change the operating pressure of the timer piston 2b is reduced accordingly.
Therefore, the responsiveness of the timer screw 1hen 2b is also improved, and timing control that fully utilizes the characteristics of the electronic control type can be realized.

The above operations and effects are exactly the same in the third embodiment, except that the pump chamber is annular. To explain the specific operations and effects in the third embodiment, the cam chamber 14
Lubricating oil (engine oil) is stored in the lower part of the roller 7a, and the lubricating oil is scraped up and scattered by the cam disk 41 rotating at high speed, and lubricates the contact portion between the cam surface and each roller 7a. Also, plunger 6 and plunger barrel 16
It also provides lubrication between the parts.

On the other hand, the fuel oil discharged from the feed pump 23 is sent to the first passage 61 → the bent passages 62 and 63 → the fuel reservoir chamber 64,
The pulsation is absorbed in the fuel storage chamber 64 and the fuel is supplied to the annular pump chamber 9 through the filtered through hole 65.

〔Effect of the invention〕

According to the first aspect of the present invention as described above, in a distribution type fuel injection pump equipped with an electronically controlled timer, the high pressure group of the timing control valve and the upstream side of the high pressure chamber are communicated with each other by a passage, and the pump chamber and the high pressure group are connected to each other by a passage. is directly connected through the passage through a fixed orifice provided in the pump housing, rather than through the timer piston, making it possible to reduce the dynamic dead volume of the hydraulic path for timer control, which improves responsiveness. This has the excellent effect of improving the control performance of the timer piston.

Further, according to the second aspect of the present invention, the pump chamber is separated from the remaining cam chamber, and lubricating oil is stored in the cam chamber independently of fuel to lubricate the cam mechanism 5.
This avoids the problem of surface peeling of the cam mechanism caused by using the wrong fuel, and provides the excellent effect of always providing good lubrication.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view showing a first embodiment of the present invention, Fig. 2 is a cross-sectional view of the lower part of the body in Fig. 1, and Fig. 3 is a partial cross-section showing a second embodiment of the invention. 48 to 4c are cross-sectional views showing aspects of the fixed orifice according to the present invention, FIG. 5 is a vertical cross-sectional side view showing the third embodiment of the present invention, and FIG. FIG. 7 is a cross-sectional view showing the relationship of the roller holder assembly; FIG. 7 is a partial cross-sectional view showing the relationship between lubricating oil in and out in the third embodiment; FIG. 8 is a partial sectional view showing a spill solenoid valve and a spill passage, FIG. 9 is a timer control system diagram in the present invention, and FIG.
The figure is a partial sectional view of a conventional pump, and FIG. 11 is an FA diagram of a timer control system using the 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, 21...Low pressure chamber, 30...High pressure group, 33...Passage, 34...Fixed orifice, 35...Passage Patent applicant Diesel Kiki Co., Ltd.

Claims (2)

[Claims] (1) A timer piston for moving the roller holder assembly and a high-pressure chamber and a low-pressure chamber on both sides of the timer piston in the axial direction are installed at the bottom of the pump housing containing a plunger that can rotate and reciprocate according to the rotation of the engine. In a fuel injection pump equipped with an electromagnetic timing control valve that communicates and shuts off, the high pressure group of the timing control valve and the upstream side of the timer piston high pressure chamber are communicated through a passage, and the high pressure group and the pump chamber are connected to the pump housing. A distribution type fuel injection pump characterized by being directly connected through a passage including a fixed orifice provided therein. (2) The pump chamber is divided into an annular shape by the inner wall of the pump housing and a cylindrical spring seat that constitutes a part of the plunger spring assembly, and the annular pump chamber is separated from the cam chamber, which is the remaining space inside the pump housing. 2. A distributed fuel injection pump according to claim 1, wherein the annular pump chamber is oil-tightly shut off, and the annular pump chamber is supplied with fuel from a feed pump by a fuel supply path that bypasses the cam chamber. .