JP3041210B2 - Distribution type fuel injection pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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 used as a fuel supply means for a diesel engine.

[0002]

2. Description of the Related Art In general, fuel injection pumps for pumping fuel to a diesel engine are roughly classified into an inner cam type fuel injection pump and a face cam type fuel injection pump. The inner-cam type fuel injection pump has a rotor having a plunger therein for performing a fuel suction and discharge operation, and a housing having the rotor rotatably provided therein. The rotor is configured to rotate in synchronization with the rotation of the diesel engine. When the rotor rotates, a fuel intake port provided in the housing communicates with a suction port provided in the rotor, and fuel is sucked in. The plunger is introduced into a pump chamber in which the plunger is disposed. Also, when the rotor rotates, a fuel discharge passage provided in the rotor is radially provided in the housing and communicates with a fuel outflow port connected to a fuel injection nozzle of each cylinder of the engine.
The fuel compressed by the operation of the plunger is pressure-fed to the fuel injection nozzle via the fuel outflow port.

On the other hand, a face cam type fuel injection pump has a plunger hole (cylinder) formed inside a pump housing, and a plunger is disposed in the cylinder. The plunger is driven by a cam plate connected to the drive shaft by a coupling, and is pressed against the cam plate by a plunger spring. This cam plate has the same number of face cams as the number of engine cylinders (cylinders), and is configured to reciprocate by a specified cam lift amount when rotated by a drive shaft.

Accordingly, the plunger connected to the cam plate rotates and reciprocates to inhale fuel and pressurize the fuel, and the pressurized fuel is supplied with the fuel discharged from the plunger as the plunger rotates. When a passage is provided in the housing and communicates with a fuel outflow port connected to the fuel injection nozzle of each cylinder of the engine, the passage is pressure-fed to the fuel injection nozzle via the fuel outflow port.

[0005] In this type of distribution type fuel injection pump, residual pressure is generated in the fuel outflow port from the housing to the fuel injection nozzle of each cylinder after fuel is discharged, and this residual pressure differs at each fuel outflow port. As a result, there is a problem that the amount of fuel supplied to each cylinder becomes uneven and the engine speed becomes unstable.

Here, the reason why the amount of fuel supplied to each cylinder becomes uneven will be described. When fuel is pumped from the fuel injection pump to the engine and injected from the fuel injection nozzle, residual pressure is generated at the fuel outflow port. The residual pressure alternately increases and decreases according to the order in which the fuel is discharged. This occurs due to a dimensional error of the plunger, an error in a lift amount by which the inner cam lifts the plunger, and the like.

On the other hand, the plunger provided in the fuel injection pump reciprocates at a high speed, and the generated fuel pressure is as high as 1000 atm. Therefore, the generated residual pressure is large, and the height difference is also large. Therefore, as a distribution type fuel injection pump configured to supply fuel uniformly to each cylinder of the engine, there is one disclosed in Japanese Utility Model Laid-Open No. 63-35757, for example. The fuel injection pump disclosed in the publication has a configuration in which a rotor is provided with a pressure equalizing port for communicating a plurality of fuel outflow ports among the fuel outflow ports outside the discharge process.

In the distribution type fuel injection pump having the above-described structure, the fuel outflow ports outside the discharge step are communicated with each other by the pressure equalizing ports. Therefore, the internal pressure between the connected fuel outflow ports is equalized. Thus, the amount of fuel supplied to each cylinder of the engine under pressure is made uniform.

[0009]

However, the conventional fuel injection pumps described above communicate with each other by providing a plurality of fuel outflow ports, each of which generates a large residual pressure and has a large difference in residual pressure, with a pressure equalizing port. In this case, the pressure of each of the connected fuel outlet ports is equalized, and the pressure difference of the unconnected fuel outlet ports cannot be eliminated.

That is, the fuel injection pump disclosed in the above publication has a configuration in which two adjacent fuel outflow ports communicate with each other through the pressure equalizing port. Despite fluctuations, it is not possible to equalize all the fuel outlet ports provided. For this reason, a pressure wave may remain at a certain fuel outlet port, and simply connecting the adjacent fuel outlet ports with the equalizing port equalizes the residual pressures of all the fuel outlet ports to the same constant level. There was a problem that it was not possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has a fuel outflow port connected to a portion having a large fuel storage capacity or a portion in which low-pressure fuel exists when the fuel outflow port is not in the discharge step. It is another object of the present invention to provide a distribution-type fuel injection pump that stabilizes fuel to be pumped to an internal combustion engine.

[0012]

Means for Solving the Problems In order to solve the above problems, the present invention is characterized by taking the following means. According to the first aspect of the present invention, fuel pressurizing means for pressurizing the fuel sucked into the pressurizing chamber, a cylinder-side discharge path connected to an injection nozzle provided in each cylinder of the internal combustion engine, and the pressurizing chamber And a discharge port in the rotor to which the fuel pressurized by the fuel pressurizing means is supplied, and the inside of the cylinder is synchronized with engine rotation. The pressurized fuel is transferred to the cylinder by selectively connecting the discharge port in the rotor to the cylinder-side discharge path of the cylinder in the discharge step with the rotation. And a rotor for distributing to the side discharge path, and the number of the cylinder side discharge paths outside the discharge process is reduced.
One for the cylinder side suction path in the suction process.
Distribution type fuel injection pump with pressure equalizing port for communication
The equalizing port is connected to the discharge port in the rotor and the
The outer periphery of the rotor is provided so as to communicate with the discharge port in the rotor.
And an annular groove that is configured to communicate with the annular groove.
It consists of a slit, and the above-mentioned slit
, A discharge port in the rotor, and an annular groove.
The pressure equalizing port communicates with the cylinder side discharge passage.
It is characterized by having achieved .

[0013]

[0014] According to the second aspect of the present invention, the first aspect is provided.
In the distribution type fuel injection pump described above, a plurality of the slits are formed on a peripheral surface on a side opposite to an arrangement position of a discharge port in the rotor with respect to a center axis of the rotor, and an arrangement position of the plurality of slits is , And is arranged so as to be symmetrical with respect to a line connecting the center of the rotor and the arrangement position of the discharge port in the rotor.

Further, according to the invention of claim 3 , according to claim 1,
In the above described distributed fuel injection pump, the pressure equalizing port is configured to simultaneously communicate with a plurality of cylinder side discharge passages outside the discharge step.

[0016]

[0017]

[0018]

According to the fourth aspect of the present invention, the engine rotation
Is rotated in synchronism with the rotation, and performs suction / discharge according to the rotation.
Rotor with pump chamber inside and syringe with rotor inside
A suction path on the cylinder side and a suction port in the rotor.
The fuel is sucked during the suction process where the
One of the cylinder side discharge passages leading to the nozzle
The fuel is pumped to the cylinder during the discharge process where the ports communicate.
And with low pressure fluctuations
A discharge chamber in the cylinder-side discharge passage
Connect the cylinder side discharge passage outside the process to the storage chamber
In the distribution type fuel injection pump provided with a pressure equalization port, said
Equalizing ports are connected to a plurality of cylinders outside the discharge process.
It is characterized in that it is configured to simultaneously communicate with the discharge passage .

According to the fifth aspect of the present invention, a rotor having a pump chamber, which is rotated in synchronization with the rotation of the engine and performs suction and discharge in accordance with the rotation, is provided in the housing, and the rotor is provided therein. And a discharge port in which the rotor discharge port communicates with one of the cylinder side discharge passages leading to the injection nozzle of each cylinder during a suction step in which the cylinder side suction path communicates with the rotor suction port. In the distribution type fuel injection pump configured to pump fuel to the cylinder during the process, the discharge port in the rotor is formed to have a predetermined length in the circumferential direction of the rotor, and is provided in the cylinder. One end is open at a position communicating with the rotor discharge port immediately before the end of the communication between the rotor discharge port and the cylinder side discharge passage,
In addition, an equalizing port having the other end connected to a low-pressure chamber provided in the housing is provided.

[0021]

Each of the above means operates as follows. According to the first aspect of the invention, at least one of the cylinder-side discharge passages outside the discharge step is communicated with the cylinder-side suction passage through the equalizing port. The cylinder side suction path is
The pressure is relatively low and the pressure change is small. Therefore, the pressure wave generated in the cylinder-side discharge passage is reduced by communicating the cylinder-side discharge passage with the above-described predetermined timing at the cylinder-side suction passage having a relatively low pressure and a small pressure change. be able to. Further, since the cylinder-side suction passage is disposed near the cylinder-side discharge passage, the pressure in the cylinder-side discharge passage can be made uniform and reliable. Also,
So that it communicates with the discharge port in the rotor, the annular groove, and the annular groove.
The pressure equalizing port constituted by the constituted slit
Make sure that the slit communicates with the cylinder side discharge passage during the
And the discharge passage on the cylinder side is slit, annular groove, low
Through the discharge port in the pump, the pump chamber, and the suction passage in the rotor.
Communicates with the cylinder side suction passage and equalizes the cylinder side discharge passage
Is performed. At this time, the slit that constitutes the equalizing port
Can be formed relatively easily, and ports and
Since there is no need to increase the number of passages, the structure of the device is simplified.
be able to.

[0022]

According to the second aspect of the present invention, the slit is formed between the center of the rotor and the discharge port in the rotor on the peripheral surface opposite to the position of the discharge port in the rotor with respect to the center axis of the rotor. The pressure equalizing port (slit) also functions as a balance port by arranging a plurality of lines so as to be symmetrical with respect to a line connecting the positions. That is, in the discharge step, the discharge force of the pressurized fuel is applied to each slit, and since the slits are arranged on the target as described above, the discharge force is uniformly applied to the rotor. For this reason, the posture of the rotor can be stabilized.

According to the third and fourth aspects of the present invention, the plurality of cylinder side discharge passages outside the discharge step are simultaneously connected to the pressure equalizing port. For this reason, the chance of equalizing the pressure in each cylinder-side discharge passage increases, and the variation in the internal pressure in the cylinder-side discharge passage between the cylinders can be suppressed.

[0025]

[0026]

Further, according to the fifth aspect of the present invention, the pressure equalizing port has one end on the rotor side communicating with the discharge port in the rotor immediately before the end of the communication state between the discharge port in the rotor and the discharge passage in the cylinder side. Since the cylinder-side discharge passage communicates with the low-pressure chamber, it is possible to equalize the pressure in the cylinder-side discharge passage and to suppress the full injection even if the electromagnetic spill valve does not operate properly. it can.

[0028]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 3 show a fuel injection pump 10 according to one embodiment of the present invention. FIG. 1 is a sectional view showing the overall configuration of the fuel injection pump 10, and FIG.
FIG. 3 is a cross-sectional view taken along the line II, and FIG. 3 is an enlarged cross-sectional view showing the vicinity of a distribution rotor.

In FIG. 1, a housing 11 is a main body of the fuel injection pump 10 and has a cam chamber 12 for accommodating various functional parts of the fuel injection pump 10 and being filled with fuel. The housing 11 is provided with an overflow valve 20, a spill valve 30, a fuel recirculation valve 40, an accumulator 50, a constant pressure valve 60, and the like. However, more specifically, the housing 11 is composed of three parts. In other words, a main body that houses the cam ring and the drive shaft,
It is composed of a distribution head section containing a cylinder, and a cover section containing a rotation sensor.

The overflow valve 20 communicates with a predetermined position of the cam chamber 12, and is a valve provided to prevent the inside of the cam chamber 12 from becoming excessive pressure. The overflow valve 20 is provided with a check valve including a ball valve 22 and a spring 24. When fuel is excessively supplied into the cam chamber 12, the excess is returned to a fuel tank (not shown).

The spill valve 30 is an electromagnetic valve that opens and closes a valve body 32 by an electromagnetic force generated by an electromagnetic coil 31.
The fuel recirculation valve 40 and the fuel suction gallery 17 described later
To a fuel leak passage (spill passage) 103 described later. The valve element 32 of the spill valve 30 is urged upward by a spring 33,
The upper end is regulated by an armature 34 for transmitting the electromagnetic force generated by the electromagnetic coil 31 and a stopper 36 urged by a spring 35.

On the other hand, the valve body 32 and its valve seat 37 are
2 is seated on the valve seat 37, that is, the spill valve 3
When 0 is closed, hydraulic pressure acts only on the side surface of the valve body 32, and when the valve body 32 is separated from the valve seat 37, that is, when the spill valve 30 is opened. Is configured such that hydraulic pressure also acts on the distal end of the valve body 32.

When the spill valve 30 is closed, the overflow (spill) of the pressurized fuel is stopped, and the fuel pressurized by the fuel injection pump 10 is pumped to the diesel engine. When the spill valve 30 is open, the pressurized fuel overflows (spills) into the cam chamber 12 or the fuel suction gallery 17 as described later.
Thus, the pumping of the fuel to the diesel engine is stopped.

The operation of the spill valve 30 will be described. The energization of the electromagnetic coil 31 is started and the electromagnetic coil 3
When 1 generates an electromagnetic force, the armature 34 operates to press the valve body 32 by the electromagnetic force. Therefore, the valve element 32
, The pressing force of the armature 34 and the urging force of the spring 35 both act in the valve closing direction. As a result, the valve body 32 is displaced against the urging force of the spring 33, and the spill valve 30 is closed.

On the other hand, when the pressing force of the armature 34 is extinguished by stopping the energization of the electromagnetic coil 31, the urging force of the spring 33 is displaced in the valve opening direction against the urging force of the spring 35. Spill valve 30
Is opened. When the spill valve 30 is opened, the fuel recirculation valve 40 opens the fuel leakage passage (spill passage) 1.
This is a valve provided to reduce the high-pressure fuel (spill fuel) spilled from the fuel tank 03 to a predetermined pressure and to recirculate the fuel to the fuel tank. As in the case of the overflow valve 20 described above, the valve includes a ball valve 42 and a spring 44. It consists of a stop valve.

The accumulator (accumulation chamber) 50 is
It is provided to absorb the pulsation of the fuel pressure in the fuel suction gallery 17. This accumulator 50
The cylinder chamber 55 communicates with the fuel chamber gallery 17 through the communication passage 56a in accordance with the pressure fluctuation of the cylinder chamber 55.
And a spring 54 for biasing the piston 52.

The cylinder chamber 55 is connected to a feed pressure supply pipe (not shown) connected to a feed pump 80 described later. Further, the cylinder chamber 5
Numeral 5 communicates with the space 19 formed at the right end of the rotor 90 in the figure through the communication hole 57 so as to supply a feed pressure to the space 19.

The constant pressure valve 60 includes a cylinder-side discharge passage 102 and a fuel discharge passage 112 in the housing 11 formed in a cylinder 100 which communicates with each other, and a fuel injection valve (see FIG. 1) provided in each cylinder of the diesel engine. When the internal pressure of the fuel discharge passage 112 exceeds a predetermined pressure and becomes high, the fuel is circulated toward the fuel injection valve at that pressure, and the internal pressure of the fuel discharge passage 112 is increased. Has a function of keeping the pressure on the fuel injection valve side at a predetermined pressure even if the pressure becomes equal to or lower than a predetermined pressure.

The provision of the constant pressure valve 60 has a function of uniformizing the fuel pressure in the pipe from the constant pressure valve 60 to a fuel injection valve of the diesel engine to some extent except during pressure feeding. When a residual pressure is generated in the side discharge passage 102 and the fuel discharge passage 112 and no equalizing port described later is provided, the residual pressure is applied to each of the passages 102.112 provided corresponding to the cylinder.
As described above, the fuel supply amounts supplied to the respective cylinders become non-uniform, and the engine speed becomes unstable.

In the cam chamber 12 of the housing 11,
A drive shaft 70 that rotates at half the rotation speed of the crankshaft of the diesel engine, and a vane-type fuel feed pump (hereinafter simply referred to as a feed pump) 80 that feeds fuel using the rotational force of the drive shaft 70 as a drive source. Rotor 90 and distribution rotor 9 rotating together with the drive shaft 70
The cylinder 100 into which the small-diameter portion 0 is inserted, the cam ring 110 surrounding the outer periphery of the large-diameter portion of the distribution rotor 90, and the like are incorporated.

The drive shaft 70 is rotatably supported in the housing 11 by a bush 13 provided near the end of the housing 11 and a bearing 14 provided inside the housing 11. Further, fuel is supplied to the bush 13 as lubricating oil in order to reduce sliding resistance. Further, an oil seal 18 is provided at an end of the drive shaft 70 connected to the diesel engine, and an oil passage 16 is provided for communicating the fuel inlet 15 and the bush 13.

At a predetermined position of the drive shaft 70, a pulser 120 having a plurality of projections 121 formed at predetermined intervals on the outer periphery thereof is provided.
Fixed to 10 is a rotation angle sensor 122 that converts the approach / separation of the projection 121 of the pulsar 120 that rotates with the drive shaft 70 into a pulse signal. By fixing the rotation angle sensor 122 to the cam ring 110 in this manner, an engine rotation signal (NE signal) can be generated at a constant timing for the plunger lift regardless of the control operation of the timer device 130 described later. it can.

The feed pump 80 is a vane type pump comprising an outer wall 81 fixed to the housing 11 and a rotor 83 having a plurality of vanes 82. That is, the fuel sucked in from the suction port 84 provided in communication with the fuel inlet 15 is pressurized by the vanes 82 with the rotation of the rotor 83 and discharged from the fuel discharge port 85 provided in a predetermined position. . The fuel discharged from the fuel discharge port 85 is supplied to the fuel suction gallery 17 and the accumulator 5.
0 is supplied to the cylinder chamber 55 through a pipe (not shown). The pressure (feed pressure) of the fuel that has been pressurized by the feed pump 80 is relatively stable.

The distribution rotor 90 is rotatably mounted in the cylinder hole 100a of the cylinder 100 in a liquid-tight manner while being engaged with the drive shaft 70. Therefore, the cylinder hole 100
“a” also functions as a bearing that rotatably supports the distribution rotor 90. The distribution rotor 90 has a large-diameter portion having a pump chamber (pressurizing chamber) 91, a small-diameter portion having a communication port 104 having one end communicating with the pump chamber (pressurizing chamber) 91, and a communication port in the discharge process. A discharge port 94 in the rotor that communicates the pump chamber 91 with the fuel discharge port 93 via the 104, and a suction port 9 in the rotor that communicates the fuel suction port 92 with the pump chamber 91 through the communication port 104 in the suction process.
5 and a pressure equalizing port 105 which is a main part of the present invention.

The pump chamber 91 has a distribution rotor 90.
A plurality of plungers (four in this embodiment) 96a to 96d that can slide in a liquid-tight manner in the radial direction are inserted.
Further, an annular groove 97 provided around the outer periphery of the distribution rotor 90 at a position offset in the axial direction is communicated with the fuel discharge port 93. The fuel outlet 93, the fuel inlet 92, and the annular groove 97 are connected to the distribution rotor 9
0 is formed on the peripheral surface of the rotor.

On the other hand, the cylinder 100 has a cylinder-side suction passage 101 communicating the fuel suction gallery 17 with the inner periphery of the cylinder 100, and a constant pressure valve 60 having one end through a fuel discharge passage 112 formed in the housing 11. A plurality of cylinder-side discharge passages 102 communicating with each other and having the other end opened to the inner periphery of the cylinder 100, the above-described fuel leakage passage (spill passage) 103, and the like are provided. The fuel gallery 17 is formed in the housing 11 and communicates with a fuel discharge port 85 of the feed pump 80 via an external pipe (not shown).

Here, a plurality of the above-described in-rotor suction ports 95 and cylinder-side discharge passages 102 are provided corresponding to the number of cylinders of the diesel engine, respectively, and the distribution rotor 90 is synchronized with the rotation angle of the diesel engine. When the engine rotates, the fuel intake gallery 17 is distributed in the intake process in accordance with the rotation angle of the diesel engine.
The fuel discharge port 93 communicates with a constant pressure valve 60 disposed in a specific cylinder in a discharge step.

Further, the cylinder 100 is provided with the fuel leakage passage (spill passage) 103 which communicates the annular groove 97 provided in the distribution rotor 90 with the spill valve 30 as described above. Here, the annular groove 97 is provided in the distribution rotor 90.
, The annular groove 97 and the spill valve 30 are always in communication regardless of the rotation angle of the distribution rotor 90.

Next, the configuration near the pump chamber 91 will be described with reference to FIG. 2, which corresponds to the II-II section in FIG. The fuel injection pump 10 of the present embodiment includes four plungers 96a to 96d inserted in the distribution rotor 90,
The pump is driven by a cam provided on the cam ring 110 to increase the pressure of the fuel. Further, the fuel pump 10 of the present embodiment corresponds to a six-cylinder internal combustion engine. Therefore, the cam ring 110 is provided with six cam lobes 110a to 110f at equal intervals as shown in FIG. I have.

The four plungers 96a to 96d
Is designed so that its lift occurs simultaneously in all the plungers 96a to 96d. That is, the plungers 96a to 96d perform a compression stroke of sliding toward the central axis of the distribution rotor 90 when passing through the cam lobes 110a to 110f, and after passing through the cam lobes 110a to 110f, move outside the distribution rotor 90. Perform a suction stroke that slides toward.

The outer peripheral ends of the plungers 96a to 96d have cam lobes 110a to 11
0f to the roller shoes 98a to 98d to smoothly transmit the cam lift to the plungers 96a to 96d.
98d and rollers 99a to 99d gripped by the roller shoes 98a to 98d are provided.

Therefore, when the distribution rotor 90 rotates inside the cam ring 110, the plungers 96a to 96d make six reciprocating motions while the distribution rotor 90 makes one revolution, and the reciprocating motion causes the plungers 96a to 96d to move inside the pump chamber 91. If the fuel is pressurized, the fuel is boosted six times at equal rotation angles while the distribution rotor 90 makes one rotation, that is, while the internal combustion engine makes two rotations.

At this time, the cylinder side suction passage 1 shown in FIG.
01 and the fuel inlet 92 are plungers 96a to 96d
Are connected in a situation where no cam lift is provided. Further, the cylinder side discharge passage 102 and the fuel discharge port 93 are configured to communicate with each other immediately before the plungers 96a to 96d are lifted.

Therefore, with the rotation of the distribution rotor 90,
When any one of the cylinder-side suction passages 101 and the fuel suction port 92 communicate with each other, the plungers 96 a to 96 d are subjected to the centrifugal force accompanying the rotation of the distribution rotor 90 and the fuel pressure (feed pressure) supplied from the feed pump 80. The fuel in the fuel suction gallery 17 is supplied to the pump chamber 91 through the cylinder side suction passage 101, the fuel suction port 92, and the communication port 104.
(Inhalation process).

Then, thereafter, the cylinder side suction passage 101
When the communication between the fuel discharge port 93 and the cylinder-side discharge passage 102 is communicated with the fuel discharge port 93 and the plungers 96a to 96d are lifted, the spill valve 30 is assumed to be closed. And the pump chamber 91
Is supplied to the constant pressure valve 60 through the communication port 104, the discharge port 94, the annular groove 97, the fuel discharge port 93, the cylinder side discharge passage 102, and the fuel discharge passage 112. (Discharge process).

On the other hand, if the above-mentioned spill valve 30 is opened when the fuel is pressurized by the plungers 96a to 96d, the fuel pressure-fed from the pump chamber 91 flows through the fuel intake gallery 17, the fuel The fuel is returned to a tank or the like, and the supply of high-pressure fuel to each cylinder of the diesel engine is stopped.

That is, the fuel injection start timing is controlled by controlling the timing of switching the spill valve 30 from the open state to the closed state, and the fuel injection end timing is controlled by controlling the timing of opening the spill valve 30. It becomes possible to control well. As described above, by controlling the fuel injection timing by performing the opening / closing control of the spill valve 30, the fuel injection amount control can be performed with high accuracy.
It is possible to operate the diesel engine in a state most suitable for the operating state.

When the high pressure fuel is spilled by using the spill valve 30, each port 9 provided in the distribution rotor 90 is provided due to the inertia effect of the fuel during the spill.
In some cases, the internal pressure at 4, 95 becomes negative pressure. When the internal pressures of these ports 94 and 95 become negative pressure, the relationship between the strokes of the plungers 96a to 96d and the amount of pumped fuel is changed, and the control accuracy of the fuel injection amount is deteriorated.

However, as described above, the spill valve 30
Part of fuel spilled through the fuel intake gallery 1
By returning the accumulator 50 to the fuel suction gallery 17 and communicating with the fuel suction gallery 17, such an adverse effect can be effectively eliminated. That is, with the above configuration, even if excessive fuel overflow occurs due to the inertial effect at the time of fuel spill, a part of the fuel overflow occurs in the fuel intake gallery 1.
7, the internal pressure pulsation caused by the recirculation of the spill fuel is appropriately absorbed by the accumulator 50, so that a sufficient amount of fuel can be stably sucked in the next fuel suction. Becomes possible.

Also, by circulating a part of the spilled fuel to the suction gallery 17, spilled fuel is supplied into the pump chamber 91 in addition to the fuel from the feed pump 80. Even at this time, the fuel supply into the pump chamber 91 can be reliably performed.

Next, the timer device 130 will be described. The fuel injection pump 10 of the present embodiment includes a housing 11
And a timer device 130 for changing the fixed angle of the cam ring 110 with respect to. That is, the cam ring 110
Are rotatably mounted on the housing 11, and as shown in FIG.
32 is fixed to a rod 133 sandwiched between them.

Here, the timer pistons 131 and 132
Is a timer housing 13 constituting the timer device 130.
0a is a piston slidably inserted into the inside of Oa. In the timer housing 130a, a high-pressure chamber 134 communicating with the fuel discharge port 85 of the feed pump 80 is provided on the right side of the timer piston 131.
A low pressure chamber 135 communicating with the fuel suction port 84 of the feed pump 80 is formed on the left side of the feed pump 80.

A spring 136 for urging the timer piston 132 rightward in FIG. 2 is disposed in the low-pressure chamber 135. The high-pressure chamber 134 and the low-pressure chamber 135 are connected to the solenoid valve (timing control) shown in FIG. The connection is made by an external pipe whose conduction is controlled by a valve (140). In this case, the timer pistons 131 and 132 are displaced left and right in the figure according to the pressure difference between the high pressure chamber 134 and the low pressure chamber 135, and accordingly, the rod 133 sandwiched between the timer pistons 131 and 132 is also urged right and left. The cam ring 110 is rotated by the urging force. Further, in the present embodiment, the opening and closing valve of the timing control valve 140 is duty-controlled so that the cam ring 110
Is controlled to a desired rotation angle.

With this configuration, the distribution rotor 90
, That is, the lift characteristics of the plungers 96a to 96d with respect to the rotation angle of the diesel engine can be changed, so that the degree of freedom regarding the fuel injection timing control can be further increased, and the fuel excellent in controllability can be obtained. An injection pump will be realized.

As described above, the timer device 130 changes the lift characteristics of the plungers 96a to 96d by rotating the cam ring 110 in the housing 11 using the timing control valve 140, and controls the injection timing. Configuration. For this reason,
A predetermined clearance is provided between the outer peripheral surface of the cam ring 110 and the inner peripheral surface of the housing 11 opposed to the cam ring 110 (because the clearance is fine, it does not appear in the drawing). The fuel is supplied from the cam chamber 12. The fuel supplied into the clearance functions as a lubricating oil.

Next, the pressure equalizing port 105 according to a first embodiment of the present invention will be described. FIGS. 1 and 3 show a fuel injection pump 10 provided with a pressure equalizing port 105 and a distribution rotor 90 according to a first embodiment of the present invention. The pressure equalizing port 105 is disposed on the distribution rotor 90, one end of which is connected to the fuel inlet 92, and the other end of which is connected to the distribution rotor 9.
The pressure equalizing opening 106 is formed in the outer periphery of the zero. The position where the pressure equalizing opening 106 is formed is selected to be a position that communicates with the cylinder side discharge passage 102 that has been out of the discharge step with the rotation of the distribution rotor 90.

Therefore, when the rotor-side opening of the cylinder-side discharge passage 102 in the suction step communicates with the equalizing opening 106, the cylinder-side discharge passage 102 is connected to the equalizing port 10.
5, a state is established in which it is communicated with the fuel suction gallery 17 via the fuel suction port 92 and the cylinder side suction passage 101.

The fuel suction gallery 17 is a portion where the fuel having a relatively stable pressure (feed pressure) is supplied from the feed pump 80 as described above, and has a relatively large capacity as compared with each port. ing. Accordingly, the internal pressure of the cylinder side suction passage 101 connected to the fuel suction gallery 17 having the stable pressure is also stable.

Therefore, the cylinder-side discharge passage 102 that has completed the discharge process and has become the suction process, in other words, the cylinder-side discharge passage 102 that has completed the discharge process and has residual pressure, By communicating with the passage 101 (the fuel suction gallery 17), the residual pressure in the cylinder side discharge passage 102 can be absorbed by the fuel suction gallery 17, and the cylinder side discharge passage 102 can be equalized in pressure.

Hereinafter, with the rotation of the distribution rotor 90, the discharge process is completed and the cylinder-side discharge passage 10 is set to the suction process.
Since 2 sequentially communicates with the pressure equalizing port 105, the cylinder-side discharge passages 102 provided corresponding to the number of cylinders are pressure-equalized sequentially. Therefore, it is possible to prevent the residual pressure in the cylinder-side discharge passage 102 from affecting the fuel discharge in the next discharge step, and to equalize the amount of fuel supplied to each cylinder. The engine speed can be stabilized. In addition, the cylinder side suction passage 10
Since 1 is disposed near the cylinder side discharge passage 102, pressure equalization can be performed stably and responsively.

FIG. 4 is an enlarged view of a distribution rotor 90A provided with a pressure equalizing port according to the second embodiment. The pressure equalizing port according to the present embodiment is characterized by comprising a discharge port 94 in the rotor, an annular groove 97, and a slit 105A. The discharge port 94 in the rotor, the annular groove 97,
The pressure equalizing port formed by the slit 105A is configured such that one end of the slit 105A communicates with the annular groove 97 formed on the outer circumference of the distribution rotor 90 described above. As described above, the annular groove 97 communicates with the discharge port 94 in the rotor, so that the fuel pressurized in the pump chamber 91 is supplied. In addition, the annular groove 9
7 has a relatively large capacity because it is formed annularly on the outer periphery of the distribution rotor 90.

Therefore, the slit 105 having the above structure
By using A, the cylinder-side discharge passage 102 in which the discharge process is completed and the suction pressure is present, and in which the residual pressure exists, is communicated with the annular groove 97, the discharge port 94 in the rotor, and the cylinder-side suction passage 101, so that the cylinder-side discharge is performed. The residual pressure in the passage 102 can be absorbed through the annular groove 97, the discharge port 94 in the rotor, and the cylinder-side suction passage 101, and the pressure in the cylinder-side discharge passage 102 can be equalized.

That is, by providing the slit 105A, the slit 105A, the annular groove 97, and the discharge port 94 in the rotor function as a pressure equalizing port. However, in the following description, only the slit 105A will be referred to as a pressure equalizing port 105A for simplification of the description.

As described above, even when the pressure equalizing port 105A according to the present embodiment is provided, the cylinder side discharge passage 1
It is possible to prevent the residual pressure in the fuel tank 02 from affecting the fuel discharge, and to equalize the amount of fuel supplied to each cylinder and stabilize the engine speed. Further, the equalizing port 105A according to the present embodiment has a slit (105A).
Can be used as a pressure equalizing port only by installing the slit, the slit can be formed relatively easily, and it is not necessary to increase the number of ports and passages, so that the distribution rotor 90 and the cylinder 100 can be simplified. it can.

In disposing the pressure equalizing port 105 A constituted by the slits on the distribution rotor 90,
As shown in FIG. 5 (a cross-sectional view taken along the line X1-X1 in FIG. 4), the pressure equalizing port 105A (slit) is connected to the discharge port 94 in the rotor (specifically, the rotor (Cylinder side opening of internal discharge port 94)
Of the distribution rotor 90
A plurality (two in this embodiment) is arranged so as to be a target with respect to a line (a dashed line indicated by reference symbol A in the figure) connecting the center of the rotor and the arrangement position of the discharge port 94 in the rotor. Is also good.

By arranging the plurality of equalizing ports 105A so as to be symmetrical as described above, the equalizing ports 105A function as balance ports during the discharge process. The operation of the pressure equalizing port 105A as a balance port will be described with reference to FIG.

FIG. 6B shows a state in which the distribution rotor 90A-1 having no pressure equalizing port 105A is used, and the discharge port 94 in the rotor provided on the distribution rotor 90A-1 is in the discharge step. Is shown. During the discharge step, high-pressure fuel flows into the annular groove 97 from the discharge port 94 in the rotor, and the distribution rotor 90A-1 is urged upward in FIG. This allows
Since the upper portion of the distribution rotor 90A-1 is in sliding contact with the inner wall of the cylinder 100 (illustrated in an exaggerated manner in the figure), the distribution rotor 90A-1 and the cylinder 100 are not provided in a configuration in which the equalizing port 105A (balance port) is not provided. Seizure may occur between the two.

On the other hand, FIG. 6A shows a state in which the pressure equalizing port 105A provided on the distribution rotor 90A provided with the pressure equalizing port 105A acting as a balance port is in the discharge step. As shown in the figure, by arranging the plurality of equalizing ports 105A so as to be targeted as described above, high-pressure fuel flows into the annular groove 97 from the in-rotor discharge port 94 during the discharge process. While the force F1 is generated, a force F2 for pressing the cylinder 100 outward by the high-pressure fuel is also generated at the pressure equalizing port 105A. The force F generated at the discharge port 94 in the rotor
1 and the force F2 generated at each pressure equalizing port 105A act in directions that cancel each other, so that the posture of the distribution rotor 90 can be stabilized, and the distribution rotor 90A and the cylinder 1
The occurrence of seizure between 00 and 00 can be prevented.

FIG. 7 shows a pressure equalizing port 10 according to the third embodiment.
The vicinity of the disposition position of the distribution rotor 90A provided with 5B is enlarged. The equalizing port 105B according to the present embodiment includes:
This is characterized in that the cylinder-side discharge passage 102 outside the discharge step in the cylinder-side discharge passage communicates with the accumulator 50.

As described above, the accumulator 50 is provided to absorb the pulsation of the fuel pressure in the fuel suction gallery 17, and the cylinder chamber 55 has a large volume. Further, the pressure in the cylinder chamber 55 is substantially constant due to the displacement of the piston 52 in the cylinder chamber 55.

Further, as described above, the feed pressure supply pipe 56 is connected to the cylinder chamber 55, so that the cylinder chamber 55 is pressurized by the feed pump 80 to have a stable pressure. Is always introduced. Further, the cylinder chamber 55
Communicates with the space 19 formed at the right end of the rotor 90 in the figure through the communication hole 57, so that the pressure in the space 19 is also stable.

On the other hand, one end of the pressure equalizing port 105B is open at the outer peripheral position of the distribution cylinder 90 and at a position communicating with the cylinder discharge passage 102 with rotation. Is formed in a substantially L-shape, so that the other end is opened at an end (the right end in the drawing) on the side different from the side where the pump chamber 91 is provided (this opening is formed as a pressure equalizing opening). 107). Therefore, the pressure equalizing opening 107 of the pressure equalizing port 105 </ b> B is configured to communicate with the space 19.

Accordingly, the discharge process is completed and the suction process is completed, so that the cylinder-side discharge passage 102 having residual pressure is communicated with the accumulator 50 through the space 19 and the communication hole 57 using the equalizing port 105B. Accordingly, the residual pressure in the cylinder-side discharge passage 102 can be absorbed by the accumulator 50, and the pressure in the cylinder-side discharge passage 102 can be equalized. Therefore, the fuel supply amount supplied to each cylinder can be made uniform, and the engine speed can be stabilized.

The equalizing opening 10 of the equalizing port 105B
Since the opening 7 is formed in the space 19 provided close to the accumulator 50, the response of the pressure equalizing process can be improved, and the size of the fuel injection pump can be reduced. FIG. 8 shows a pressure equalizing port 105C according to the fourth embodiment.
Is enlarged and shows the vicinity of the cylinder 100 provided with.

The equalizing port 105C according to this embodiment is characterized in that it is formed on the cylinder 100 side. Further, an opening (shown by reference numeral 94a in the drawing) of the discharge port 94 in the rotor on the cylinder 100 side is provided.
Has a predetermined length in the circumferential direction.

The distribution rotor 90 of the equalizing port 105C
One end opening (indicated by reference numeral 108 in the drawing) is formed between the end 94a of the discharge port 94 in the rotor and the discharge port 94 in the rotor by the annular groove 97 and the discharge passage 10 on the cylinder side.
Immediately before the end of the state of communication with the discharge port 2, it is formed at a position that communicates with the discharge port 94 in the rotor.

This will be described in detail with reference to FIG. As shown in FIG.
The opening 94a on the side has an elliptical shape having a predetermined length in the circumferential direction of the distribution rotor 90, for example. The opening 94a moves in the direction indicated by the arrow in the figure with the rotation of the distribution rotor 90.

FIG. 9A shows a state in which the discharge port 94 in the rotor and the discharge passage 102 on the cylinder side communicate with each other. At this time, the high-pressure fuel flowing out of the discharge port 94 in the rotor is first discharged from the cylinder 100 of the discharge port 94 in the rotor.
The high-pressure fuel flows into the annular groove 97, and then flows into the cylinder-side discharge passage 102.
To the constant pressure valve 60 (that is, to the engine).

FIG. 9B shows a state in which the opening 94a has moved in the direction indicated by the arrow (left direction) with the rotation of the distribution rotor 90. One end opening 108 of the pressure equalizing port 105C on the distribution rotor 90 side is formed in the moving direction of the opening 94a. However, in the state shown in FIG.
4 is not in communication.

Further, with the rotation of the distribution rotor 90, the opening 9
FIG. 9C shows a state in which 4a has moved in the direction indicated by the arrow in the figure (left direction). In the state shown in the figure, for the first time, the pressure equalizing port 105C is brought into communication with the discharge port 94 in the rotor. This state is a state immediately before the communication state between the discharge port 94 in the rotor and the discharge passage 102 on the cylinder side ends, and the formation position of the one end opening 108 of the pressure equalizing port 105C on the distribution rotor 90 side realizes this state. It is selected in the position where it can be done.

With the above configuration, the pressure equalizing port 1
Immediately before the end of communication between the in-rotor discharge port 94 and the cylinder-side discharge passage 102, the end of the pressure equalizing port 105C on the side different from the opening 108 has a relatively large volume. And is connected to the fuel suction gallery 17 having a stable pressure, so that the cylinder side discharge passage 102 can be equalized in pressure. Even if the above-mentioned spill valve 30 does not operate properly, the high-pressure fuel discharged from the discharge port 94 in the rotor is returned to the fuel suction gallery 17 through the equalizing port 105C. Can be suppressed.

FIG. 10 shows a pressure equalizing port 1 according to the fifth embodiment.
The distribution rotor 90B provided with 05D is shown. FIG.
FIG. 10A is an enlarged view of the distribution rotor 90B, and FIG.
FIG. 10B is a cross-sectional view taken along line X2-X2 in FIG. 10A in a state where the distribution rotor 90B is disposed in the cylinder 100.

This embodiment is characterized in that the equalizing port 105D is simultaneously connected to a plurality of (two in this embodiment) cylinder side discharge passages 102a and 102b outside the discharge process. It is. Specifically, the shape of the opening 105D-1 formed on the outer periphery of the distribution rotor 90B of the equalizing port 105D is elongated along the outer periphery of the distribution rotor 90, and the adjacent cylinder-side discharge passages 102a, 102a are formed.
02b (outside the ejection step) is communicated through the opening 105D-1.

As described above, since the plurality of cylinder-side discharge passages 102a and 102b outside the discharge step are simultaneously connected to the pressure equalizing port 105D, the pressure in each of the cylinder-side discharge passages 102a and 102b is equalized. And the variation in the internal pressure of the cylinder side discharge passages 102a and 102b between the cylinders can be suppressed. Therefore, the pressure can be further equalized as compared with a configuration in which the pressure equalizing process is performed only on the inside of one cylinder-side discharge passage 102, so that the fuel supply amount supplied to each cylinder is further uniformed. In addition, the engine speed can be stabilized.

[0095]

As described above, according to the present invention, the following various effects can be obtained. According to the first aspect of the present invention, it is possible to prevent the residual pressure in the cylinder side discharge passage from affecting the fuel discharge, and to equalize the amount of fuel supplied to each cylinder and stabilize the engine speed. Can be achieved. In addition, since the cylinder-side suction passage is disposed near the cylinder-side discharge passage, the pressure can be stably and responsively equalized. In addition, the equalizing port has a slit
This slit is relatively easy to form
Without the need for additional ports and passages.
Therefore, the device structure can be simplified. Also,
According to the second aspect of the present invention, the pressure equalizing port is used during the discharging process.
(Slit) can act as balance port
Therefore, the posture of the rotor can be stabilized.

[0096]

According to the third and fourth aspects of the present invention, the chance of equalizing the pressure in each cylinder-side discharge passage increases, and the variation in the internal pressure in the cylinder-side discharge passage between the cylinders can be suppressed. I can .

[0098]

Further, according to the fifth aspect of the present invention, it is possible to equalize the pressure in the cylinder side discharge passage and to suppress the full injection even if the electromagnetic spill valve does not operate properly. be able to.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing the entire configuration of a fuel injection pump according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is an enlarged sectional view showing a distribution rotor.

FIG. 4 is a diagram for explaining a pressure equalizing port according to a second embodiment.

FIG. 5 is a diagram showing a configuration in which a pressure equalizing port according to a second embodiment also functions as a balance port.

FIG. 6 is a diagram for explaining an effect of a configuration in which the equalizing port according to the second embodiment also functions as a balance port.

FIG. 7 is a view for explaining a pressure equalizing port according to a third embodiment.

FIG. 8 is a view for explaining a pressure equalizing port according to a fourth embodiment.

FIG. 9 is a diagram for explaining the operation of a pressure equalizing port according to a fourth embodiment.

FIG. 10 is a view for explaining a pressure equalizing port according to a fifth embodiment.

[Explanation of symbols]

 Reference Signs List 10 fuel injection pump 11 housing 12 cam chamber 17 fuel suction gallery 20 overflow valve 30 spill valve 40 fuel recirculation valve 50 accumulator 60 constant pressure valve 70 drive shaft 80 feed pump 85 fuel discharge port 90, 90A, 90B distribution rotor 91 pump chamber 92 fuel Inlet port 93 Fuel outlet port 94 Rotor discharge port 94a Cylinder side opening 95 Rotor suction port 96a to 96d Plunger 97 Annular groove 100 Cylinder 101 Cylinder side suction passage 102, 102a, 102b Cylinder side discharge passage 103 Fuel spill passage 104 Communication port 105, 105A to 105D Equalizing port 106, 107 Equalizing opening 108 Rotor side opening 110 Cam ring 110a to 110f Cam peak 112 Fuel Out passage 120 pulser 122 rotation angle sensor 130 timer device 131 and 132 the timer piston 140 the timing control valve

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshiyasu Ito 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Noboru Watanabe 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation ( 72) Inventor Koichi Nagatani 1-1-1 Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (56) References JP-A-63-16165 (JP, A) JP-A-59-190467 (JP, A) Kaihei 6-294360 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F02M 41/14 340 F02M 41/14 350

Claims (5)

(57) [Claims] 1. A fuel pressurizing means for pressurizing fuel sucked into a pressurizing chamber, a cylinder-side discharge path connected to an injection nozzle provided in each cylinder of an internal combustion engine, and a fuel into the pressurizing chamber. A cylinder in which a cylinder-side suction path to be supplied is formed, and a discharge port in the rotor to which the fuel pressurized by the fuel pressurizing means is supplied, and which is rotated in the cylinder in synchronization with engine rotation. With the rotation, the discharge port in the rotor is selectively connected to the discharge path on the cylinder side of the cylinder in the discharge step, so that the pressurized fuel is transferred to the discharge path on the cylinder side. And a rotor that distributes at least one of the cylinder-side discharge paths outside the discharge process.
One communicates with the cylinder side suction path in the suction process
Distribution injection pump with pressure equalizing port
The equalizing port is connected to the discharge port in the rotor and the rotor.
Provided on the outer periphery so as to communicate with the discharge port in the rotor
An annular groove and a slit configured to communicate with the annular groove
Constituted by, during the suction step, the slits, the rotor in the discharge port
And a pressure equalizing port composed of an annular groove.
A distribution-type fuel injection pump characterized in that the distribution-type fuel injection pump is configured to communicate with a discharge passage on the side of the fuel injector. 2. The dispensing type fuel injection pump according to claim 1, wherein the slit is formed so that the slit is disposed inside the rotor with respect to a central axis of the rotor.
A plurality of slits are formed on the peripheral surface opposite to the position where the outlet port is provided, and the positions where the plurality of slits are provided are located inside the rotor.
With respect to the line connecting the core and the location of the discharge port in the rotor
A distribution-type fuel injection pump, which is disposed so as to be targeted . 3. The distribution type fuel injection pump according to claim 1,
In addition, the equalizing port is connected to a plurality of the syringes outside the discharge step.
A distribution type fuel injection pump characterized in that the distribution type fuel injection pump is configured to be simultaneously communicated with a damper side discharge passage . 4. The engine is rotated in synchronization with the rotation of the engine.
A rotor with a pump chamber for suction and discharge
A cylinder in which a rotor is provided, and a suction port in which a suction path on the cylinder side communicates with a suction port in the rotor.
During the injection process, fuel is sucked in and the system reaches the injection nozzle of each cylinder.
A discharge port in the rotor communicates with one of the discharge passages on the cylinder side
Pumping fuel to the cylinder during the discharge process.
And a storage chamber with low pressure fluctuations in which fuel is stored.
And Bei, cylinder located at the ejection step outside of the cylinder-side discharge passage
A pressure equalizing port is provided for communicating the discharge side discharge passage with the storage chamber.
In the distribution type fuel injection pump, the pressure equalizing port is connected to the plurality of cylinders outside the discharge step.
A distribution type fuel injection pump characterized in that it is configured to simultaneously communicate with a side discharge passage . 5. A rotating device in a housing in synchronization with rotation of the engine.
Inside the pump chamber, which performs suction and discharge according to the rotation.
And a cylinder in which the rotor is installed.
And the suction path between the cylinder side suction path and the suction port in the rotor communicates.
During the injection process, fuel is sucked in and the system reaches the injection nozzle of each cylinder.
A discharge port in the rotor communicates with one of the discharge passages on the cylinder side
Pumping fuel to the cylinder during the discharge process.
In the distribution type fuel injection pump, the discharge port in the rotor has a predetermined length in the circumferential direction of the rotor.
And is provided in the cylinder, one end of which is provided in the rotor discharge port.
Immediately after the communication between the port and the cylinder side discharge passage ends.
Before opening it, open it to a position communicating with the discharge port in the rotor.
And a low-pressure chamber having the other end provided in the housing.
A distribution type fuel injection pump characterized by comprising a pressure equalizing port configured to communicate with the fuel injection pump.