JP2002098024A - Electronically controlled fuel injection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronically controlled fuel injection system that extends the range of operation enabling stable engine control by improving responsiveness in both opening and closing of an on-off valve coupled to an armature of a solenoid valve device and reducing stably controllable minimum fuel injection quantity, and that can maintain appreciable sealing performance of a valve seat portion for a long time by preventing the occurrence of partial wear of seat portions of the on-off valve and a valve seat. SOLUTION: The electronically controlled fuel injection system is so designed that an oil feed and drain line connected from a plunger chamber to a lubricated side is opened and closed by an on-off valve driven direct by a solenoid valve device, and that the timing at which the on-off valve closes the oil feed and drain line is changed to control fuel injection timing. The on-off valve is relatively movably coupled with an armature. A stopper mechanism holds only the armature movable in a fixed range of the initial attraction phase of the armature before stopping the relative movements of the armature and the on-off valve to hold the armature and the on-off valve integrally movable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an armature which is attracted to a solenoid of a solenoid valve device by energization of the solenoid and which is released by shutting off the energization, and reciprocated by being connected to the armature. The opening / closing valve that is moved in the direction of closing the oil supply / discharge passage to the plunger chamber of the fuel injection pump at the time of suction of the fuel injection pump changes the timing of closing the oil supply / discharge passage to control the fuel injection timing. The present invention relates to an electronically controlled fuel injection device for an internal combustion engine.

[0002]

2. Description of the Related Art In diesel engines, electronically controlled fuel injection devices have been widely used in recent years as an effective means for realizing NOx (nitrogen oxide) reduction while maintaining high combustion efficiency. FIG. 7 shows an example of a prior art of an electromagnetic valve device and a fuel injection control opening / closing valve in an electronically controlled fuel injection device of a unit injector used in a diesel engine. FIG. 7A shows a fully opened state, and FIG. Indicates time.

In FIG. 7, reference numeral 20 denotes a solenoid valve device, 3 denotes a pump case of a unit injector (see FIG. 5), 52
Is a fuel passage bored in the pump case 3 and communicates with the plunger chamber 25 of the unit injector. In the solenoid valve device 20, 31 and 16 are valve cases, 031 is a solenoid chamber formed in the valve case 31, 28 is a solenoid housed in the solenoid chamber 031, and 27 is an armature chamber 3 in the solenoid 28.
This is an armature which is arranged with 0 and fixed to the upper end of a poppet valve 5 described later by a bolt 29.

A valve seat member 10 is fixed in the pump case 3 by a fixing screw 015. Numeral 033 is a passage hole drilled in the valve seat member 10 in the radial direction, and communicates an oil chamber 17 and an oil sump 05 described later. 5 is reciprocally slidably fitted into the valve seat member 10 and has a bolt 2 at the upper end.
Reference numeral 9 denotes a poppet valve fixed to the armature 27. A valve spring 14 is provided between the fixing screw 015 and the upper surface of the poppet valve 5 and urges the poppet valve 5 in a valve opening direction, that is, in a direction against the suction force of the armature 27. Reference numeral 05 denotes an annular oil reservoir recessed on the outer periphery of the poppet valve 5, and reference numeral 17 denotes the valve seat member 1.
0 is an annular oil chamber formed facing the outer periphery of the oil chamber 0. Reference numeral 12 denotes an oil supply / discharge hole which communicates with the oil chamber 17, and the inlet side is connected to an oil supply tank (not shown). Reference numeral 10a denotes an annular seat surface formed on the valve seat member 10, and 5a denotes an annular seat surface formed on the poppet valve 5 and attached to and detached from the seat surface 10a. By attaching / detaching 5a to / from the seating surface 10a, the oil supply / drain hole 12 and the fuel passage 52 communicate with each other and are shut off.

In such an electronically controlled fuel injection device, when the power supply to the solenoid 28 of the electromagnetic valve device 20 is cut off, the poppet valve 5
4, the armature 27 is pushed downward.
And a lower end surface of the solenoid 28, a space S is formed, the lower end surface 5b of the poppet valve 5 abuts the bottom surface 3a on the pump case 3 side, and the seat surface 5a of the poppet valve 5 is Of the poppet valve 5 away from the seat 10a of the
Opens.

As a result, the plunger chamber 25 is connected to the fuel passage 52, the opening passage of the poppet valve 5, and the valve seat member 10.
The fuel in the plunger chamber 25 displaced by the downward movement of the plunger 1 passes through the fuel passage 52, the passage hole 033, and the oil passage 17 through the passage hole 033 and the oil chamber 17. The oil is returned to an oil tank (not shown) via the oil chamber 17 and the oil supply / discharge passage 12, and no fuel injection is performed.

On the other hand, the solenoid 2 of the solenoid valve device 20
When the current is increased and the amount of current is increased, the armature 27 and the poppet valve 5 fixed thereto are opposed to the elasticity of the valve spring 14, and the seat surface 5a of the poppet valve 5 is The poppet valve 5 is sucked upward until it is seated on the seating surface 10a, and the poppet valve 5 is closed. By closing the poppet valve 5, the fuel passage 52 to the plunger chamber 25 and the supply / discharge oil passage 12 are shut off, and the return amount of the fuel becomes 0 (zero). As a result, the plunger chamber 25 is closed, the pressure rise in the plunger chamber 25 due to the downward movement of the plunger 1 increases, and the fuel discharged by the plunger 1 is injected into the injection hole of the fuel injection nozzle 2 as described above. 02a is injected into the combustion chamber.

[0008] As an electronically controlled fuel injection device for an internal combustion engine, the invention of Japanese Patent No. 2600873 is provided. In this invention, a first spring having a small spring constant and a second spring having a large spring constant are serially connected to the armature sucked by the solenoid and the poppet valve fixed thereto via a spring receiver having a stopper. When the poppet valve is closed, the first spring having a small spring constant is compressed first, and the second spring having a large spring constant is actuated after the stopper hits, so that the two springs are combined. As a result, the response at the time of closing the valve is improved, and the set load of the two springs can be adjusted.

[0009]

SUMMARY OF THE INVENTION In a diesel engine having the above-described electronically controlled fuel injection device, the responsiveness of a poppet valve for controlling the communication between the plunger chamber and the oil supply / discharge passage and shutting off is improved. Accordingly, it is required to reduce a minimum injection amount of fuel that can be stably controlled by the electronically controlled fuel injection device, and to expand an operable region in which the diesel engine can be stably controlled. The minimum fuel injection amount as described above is the injection amount when the poppet valve is closed and immediately opened, and the injection amount is determined by the responsiveness of the poppet valve. Therefore, if the responsiveness of the poppet valve is improved, the minimum injection amount that can be controlled stably is reduced to expand the operable range, thereby reducing the idling speed of the engine and reducing the fuel consumption. In addition, the operation control width at the time of the idling operation has a margin, thereby enabling a stable operation, and further enabling the operation control of the engine with less power consumption.

In this electronically controlled fuel injection device, the seat portion of the poppet valve and the valve seat member to which the poppet valve is attached / detached are made uniform in the circumferential direction to reduce uneven wear of the seat portion. It is also required to prevent the occurrence and maintain a good sealing property of the poppet valve for a long time.

However, the above-mentioned prior art has the following problems, and cannot satisfy the above requirements. That is, in the prior art shown in FIG. 7, the poppet valve 5 fixed to the armature 27 sucked by the solenoid 28 is pulled back by one valve spring 14 in the valve opening direction. When the suction force of the solenoid 28 is constant and the spring constant of the valve spring 14 is increased, the poppet valve 5
When the valve is opened, the responsiveness increases, but when the valve is closed, the suction resistance of the solenoid 28 increases and the responsiveness decreases.

On the other hand, when the spring constant of the valve spring 14 is reduced, the suction resistance of the solenoid 28 is reduced, and the responsiveness when the poppet valve 5 is closed is increased.
When the valve is opened, the response is reduced because the spring constant is small. That is, in the prior art shown in FIG. 7, it is substantially impossible to obtain high responsiveness both when the poppet valve 5 is opened and when it is closed. Further, in the related art, the solenoid 28 is configured as a so-called E-shaped core having a rectangular shape in order to prevent eddy current loss, and the armature 27 has a non-rotatable structure correspondingly. I have. Therefore, the armature 27 having such a structure is used.
The seat surface 5a of the non-rotatable poppet valve 5 and the seat surface 10a of the valve seat member 10 are always in contact at the same place, and uneven wear easily occurs.

[0013] In the invention of Japanese Patent No. 2600873, two springs having large and small spring constants are arranged and attached in series to the armature and the poppet valve fixed thereto, and when the poppet valve is closed, the spring is first placed. A spring with a small constant is applied first, and then a spring with a large spring constant is added to improve the responsiveness when the valve is closed as a large spring constant obtained by combining the two springs. Since the poppet valve is returned only by a spring having a small spring constant from the middle of the return stroke of the poppet valve, the responsiveness is low, and it is difficult to obtain high responsiveness in both opening and closing of the poppet valve. Becomes Further, in this invention, since the poppet valve is fixed to the non-rotatable armature, the seat portion of the poppet valve and the valve seat always come into contact at the same place as in the above-mentioned prior art, resulting in uneven wear. Is easy to occur.

The present invention has been made in view of the above-mentioned problems of the prior art,
By obtaining high responsiveness both when the on-off valve such as a poppet valve connected to the armature of the solenoid valve device is opened and closed, the minimum injection amount of fuel that can be controlled stably is reduced, Electronic control that expands the operable area in which the valve can be controlled stably, prevents uneven wear of the seat between the on-off valve and the valve seat, and maintains a good sealing property of the valve seat for a long time. It is an object to provide a fuel injection device.

[0015]

In order to solve the above-mentioned problems, the present invention is directed to a first aspect of the present invention, wherein the solenoid is attracted by the solenoid of the solenoid valve device when the solenoid is energized, and the suction is released by interrupting the energization. An armature that is connected to the armature, reciprocates and moves in a direction to close the oil supply / drain passage to the plunger chamber of the fuel injection pump when the armature is suctioned, and the on / off valve in the valve opening direction. An electronically controlled fuel injection device comprising a biasing valve spring and configured to control fuel injection timing by changing a timing at which the on-off valve closes the supply / drain oil passage, wherein the armature and the on-off valve are The on-off valve is connected so as to be relatively movable in the axial direction, and when the armature is sucked, only the armature can be moved within a certain range at the initial suction. After a circumference proposes an electronic controlled fuel injection apparatus characterized by comprising comprises a stopper mechanism for moving integrally with the said armature and the on-off valve engages a relative movement between the armature and the on-off valve.

According to a second aspect of the present invention, in addition to the first aspect, an armature spring that is compressed by the armature when the armature moves within the predetermined range is interposed between the armature and the on-off valve. In the certain range, the armature moves against the elasticity of the armature spring by the suction of the solenoid, and after the armature is locked by the stopper mechanism, the armature and the on-off valve are connected to the valve spring. Characterized in that it is configured to move against the elasticity of the object.

The invention according to claims 3 and 4 relates to a specific configuration of the on-off valve. The invention according to claim 3 is the invention according to claim 2, wherein the on-off valve is an annular seat surface formed on a valve seat member. And a poppet valve having an annular seat surface for opening and closing the oil supply / drain passage by attaching and detaching the oil supply / drain passage. According to a fourth aspect of the present invention, in the second aspect, a valve case provided with a passage hole communicating with the oil supply / drain passage is provided, and the on-off valve is reciprocated in the valve case to supply / discharge the oil. It consists of a spool valve that opens and closes an oil passage.

According to a fifth aspect of the present invention, in the fourth aspect, a single passage hole of the valve case is provided, and the spool valve has a plurality of continuous circumferences having different depths in the axial direction of the spool valve. All of the plurality of grooves communicate with the passage hole in the minimum lift range of the spool valve, and the groove having a smaller depth becomes the passage hole as the lift increases. And all of the plurality of grooves are configured to close the passage hole in the maximum lift range.

According to this invention, the armature and the on-off valve are connected so as to be relatively movable in the axial direction, and only the armature is movable by the stopper mechanism in a certain initial range of the suction of the armature. ,
At the start of the lift of the on-off valve, the armature collides with the on-off valve due to the movement of only the armature in a certain range at the initial stage of the suction, so that the on-off valve is given an initial speed. And armatures) can reach the valve lift in a shorter time (faster) than in the prior art. Therefore, according to this invention, the responsiveness of the on-off valve is higher than in the prior art.

According to this invention, as described above, the armature and the on-off valve are connected so as to be relatively movable in the axial direction, and the armature is moved by a stopper mechanism within a predetermined range at the initial stage of suction of the armature. By causing the valve to collide with the on-off valve, an initial speed is applied to the on-off valve and the lift is started, so that the time from full opening to full closing of the on-off valve is shorter than in the related art. As a result, the time during which the passage area is reduced in the on-off valve portion is reduced as compared with the prior art, and therefore, the time during which the fuel injection pressure increases is shorter than in the prior art, and the on-off valve is closed and immediately opened. It is possible to make the minimum fuel injection amount at the time of the fuel injection smaller than that of the related art.

Therefore, according to the present invention, as described above, the responsiveness of the on-off valve is increased and the minimum fuel injection amount can be reduced as compared with the prior art, so that the control is stably performed up to the low injection range. It becomes possible. As a result, the stable operation range of the engine can be expanded to a low load and low rotation range, the idling speed can be reduced, and low noise and low fuel consumption of the engine during idling operation can be realized.

According to the second and third aspects of the present invention,
Since the armature is reciprocally fitted to the stopper mechanism fixed to the poppet valve, the poppet valve is rotated by the rotational force applied in the winding direction of the valve spring when the poppet valve reciprocates. Becomes possible.
Thereby, the annular seat surface of the poppet valve can be relatively rotated with respect to the annular seat surface formed on the valve seat member, and the seat surface and the seat surface locally generate a strong contact. Is avoided, and it is always attached and detached evenly,
The occurrence of uneven wear of the seat portion between the poppet valve and the valve seat member is prevented, and good sealing performance of the valve seat portion can be maintained for a long time.

According to the fourth and fifth aspects of the present invention,
An extremely simple and low-cost device that combines a slotted spool valve with one end fixed to an armature operated by a solenoid of a solenoid valve device and a return hole, and has a low cost. Reduction of the amount of NOx generated due to suppression of premixed combustion by moderating the rise of the fuel injection rate and fuel injection pressure, and the injection mode of high pressure and large injection quantity due to the increase of the fuel injection rate and fuel injection pressure in the later stage of injection Two-stage fuel injection control with high-efficiency combustion can be performed.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not merely intended to limit the scope of the present invention, but are merely illustrative examples unless otherwise specified. Absent.

FIGS. 1 and 2 are sectional views showing the vicinity of a solenoid valve device and a poppet valve in an electronic control fuel injection device of a unit injector for a diesel engine according to a first embodiment of the present invention. FIG. 2 (A) shows the start of the poppet valve lift, and FIG. 2 (B) shows the poppet valve fully closed. FIG. 3 is a view corresponding to FIG. 1 showing the second embodiment, and FIG. 4 is an operation explanatory view in which the vicinity of the spool valve groove in the second embodiment is enlarged. FIG. 5 is a configuration diagram including a cross-sectional view along the plunger center line near the solenoid valve device and the sleeve valve in the electronically controlled fuel injection device of the unit injector for the diesel engine according to the first embodiment. FIG. 6 is an explanatory diagram of the operation in the first and second embodiments. FIG. 7 is a view corresponding to FIG. 1 showing the prior art, and FIG.
(B) shows when the poppet valve is fully closed.

In FIG. 5, which shows an electronically controlled fuel injection device for a unit injector for a diesel engine according to the first embodiment, reference numeral 100 denotes a unit injector, which is formed by integrating a fuel injection pump unit 101 and a fuel injection nozzle unit 102. The fuel injection pump section 101 is configured as follows. Reference numeral 3 denotes a pump case, and 1 denotes a plunger fitted in the pump case 3 so as to be slidable back and forth. Reference numeral 25 denotes a plunger chamber formed facing the lower surface of the plunger 1. Reference numeral 52 denotes a fuel passage provided in the pump case 3 and communicated with the plunger chamber 25. The fuel passage 52 constitutes a supply / discharge passage of fuel to / from the plunger chamber 25, and a supply / discharge oil passage via a poppet valve portion described later. 12 is connected.

6 is a tappet abutting on the upper end of the plunger 1, and 7 is the tappet 6 and a rocker arm 5 described later.
A contact piece 8 interposed between the plunger 4 and the tappet 6 is a plunger spring interposed between the tappet 6 and the upper surface of the pump case 3 for urging the plunger upward.

The fuel injection nozzle section 102 is configured as follows. Reference numeral 2 denotes a fuel injection nozzle having a plurality of injection holes 02a drilled at the tip. Reference numeral 4 denotes a needle valve which is reciprocally slidably fitted to the fuel injection nozzle 2, 51 denotes a needle valve spring for urging the needle valve 4 in a valve closing direction, and 64 denotes a spring in which the needle valve spring 51 is housed. A case 052 is a fuel passage connecting the fuel passage 52 of the fuel injection pump unit 101 and the oil sump 02 opened and closed by the needle valve 4.
The fuel injection nozzle 102 is provided with a cap nut 53
The pump case 3 of the fuel injection pump section 101
It is screwed to a screw formed at the lower part, and is integrated with the fuel injection pump unit 101.

Reference numeral 61 denotes a fuel cam having a profile set to a required fuel injection mode and rotating in conjunction with a crankshaft of the engine. 62 is a cam shaft center. Reference numeral 58 denotes a cam follower swingably supported by a support shaft 59, reference numeral 60 denotes a roller rotatably supported by the free end of the cam follower 58 and rolled on the fuel cam 61, and reference numeral 57 denotes a push rod. Reference numeral 54 denotes a rocker arm which is swingably supported around a rocker shaft 55.
The other end is in contact with the upper end of the push rod 57 via an adjusting screw 56. The basic configuration of the unit injector 100 described above is the same as the conventional one.

Reference numeral 20 denotes an electromagnetic valve device,
Armature 27, as will be described later.
, The poppet valve 5 is driven. An electromagnetic valve control device 45 controls the operation of the solenoid 28 of the electromagnetic valve device 20. The electromagnetic valve control device 45 receives a detection signal of the engine speed from a rotation speed detector 46, and receives an engine load (engine load) from a load detector 47. (Engine output) are input.

FIGS. 1 and 2 show details of the vicinity of the solenoid valve device and the poppet valve in the first embodiment.
Reference numeral 0 denotes an electromagnetic valve device, which is configured as follows. 31 is a valve case, 031 is a solenoid chamber formed in the valve case 31, and 28 is a solenoid housed in the solenoid chamber 031. 30 is an armature chamber formed below the solenoid 28, and 27 is an armature chamber 3
An armature housed in the poppet valve 5 is attached to an upper end of the poppet valve 5 by means described later.

A valve seat member 10 is fixed in the pump case 3 by a fixing screw 015. Reference numeral 033 denotes a passage hole drilled in the valve seat member 10 in the radial direction, and communicates an oil chamber 17 and an oil sump described later. The poppet valve 5 is reciprocally slidably fitted in the valve seat member 10. A valve spring 14 is provided between the fixing screw 015 and the upper surface of the shoulder of the poppet valve 5, and is urged in a valve opening direction, that is, in a direction against the suction force of the armature 27. I have. Reference numeral 05 denotes an annular oil reservoir recessed on the outer periphery of the poppet valve 5, and reference numeral 17 denotes an annular oil chamber formed facing the outer periphery of the valve seat 10. Reference numeral 12 denotes an oil supply / discharge hole which communicates with the oil chamber 17, and the inlet side is connected to an oil supply tank (not shown). 10a is an annular seating surface formed on the valve seat member 10, 5a is the poppet valve 5
An annular seat surface which is formed on the seat surface 10a and is detachably attached to the seat surface 10a.
Is attached to and detached from the seat 10a, so that the oil supply / drain hole 1
2 and the fuel passage 52 are communicated and blocked.

Numeral 11 designates a bolt 2 above the poppet valve 5.
A cylindrical stopper 15 fixed by 9 is an armature spring composed of a compression spring installed between the upper surface of the armature 27 and the lower surface of the shoulder of the bolt 29. The elasticity of the armature spring 15 is set smaller than the elasticity of the valve spring 14 by a predetermined amount. As shown in FIG. 1B, the armature 27 has its inner peripheral surface 27b fitted to the small-diameter portion outer peripheral surface 11b of the stopper 11 so as to be able to reciprocate.
8 is pressed against the upper surface 5c of the poppet valve 5 by the resilience of the armature spring 15 when the energization of the solenoid 28 is stopped.
The upper surface 27A of the armature 27 is mounted so as to be movable along the small diameter portion outer peripheral surface 11b of the stopper 11 until the upper surface 27A of the armature 27 comes into contact with the locking surface 11a formed on the stopper 11 due to the suction force.

Next, the operation of the first embodiment of the electronically controlled fuel injection device having the above-described configuration will be described with reference to FIGS. In FIG. 6, (1) shows the present invention, and (2) shows the prior art of FIG. During operation of the engine, as shown in FIG. 5, the rotation of the fuel cam 61 causes the roller 60 to be lifted by the swing of the cam follower 58,
When the push rod 57 moves upward, the rocker arm 54 swings around the rocker shaft 55, and the plunger 1 is pressed down against the elasticity of the plunger spring 8 via the contact piece 7 and the tappet 6, the following will be described. Thus, the compression of the fuel supplied from the oil supply / discharge passage 12 into the plunger chamber 25 via the poppet valve 5 and the fuel passage 52 starts.

At the time of the compression of the fuel, as shown in FIG. 1, in a state where the power to the solenoid 28 of the solenoid valve device 20 is cut off, the poppet valve 5
The lower end face 5b of the poppet valve 5 is pushed downward by the elasticity of the valve spring 14 so that the bottom face 3a on the pump case 3 side is formed.
, The seat surface 5a of the poppet valve 5 separates from the seat surface 10a of the valve seat member 10, and the poppet valve 5 opens to the fully open lift h. As a result, the plunger chamber 25 is communicated with the supply / discharge oil passage 12 through the fuel passage 52, the opening passage of the poppet valve 5, the passage hole 033 of the valve seat member 10, and the oil chamber 17. The fuel in the plunger chamber 25 displaced by the downward movement is returned to an oil supply tank (not shown) through the fuel passage 52, the passage hole 033, the oil chamber 17, and the oil supply / discharge passage 12, and fuel injection is performed. Absent.

Next, when the energization of the solenoid 28 of the solenoid valve device 20 starts and the attraction force of the solenoid 28 becomes larger than the elasticity of the armature spring 15, the inner circumference of the solenoid 28 as shown in FIG. The armature 27 whose surface 27b is reciprocally fitted to the outer peripheral surface 11b of the small diameter portion of the stopper 11 is sucked upward against the elasticity of the armature spring 15, and the outer peripheral surface of the small diameter portion of the stopper 11 It moves along the stroke e along the stroke 11b, and its upper surface 27a comes into contact with the locking surface 11a of the stopper 11, so that e = 0 (period A in FIG. 6). In this state, as described above, the armature 27
Since only the solenoid 28 is sucked by the solenoid 28, the poppet valve 5 does not move and remains open (lift = h). This movement of the armature 27 is shorter than the prior art shown in FIG. 6B because the elasticity of the armature spring 15 is set smaller than the elasticity of the valve spring 14 and only the armature 27 is sucked. The armature 27 can be sucked in a short time (high speed) and with a small suction force.

The inertia force TP of the armature 27 when the upper surface 27a of the armature 27 comes into contact with the locking surface 11a of the stopper 11 so that the suction force of the solenoid 28 is larger than the elastic force of the spring 14. The valve spring 14 and the arm and the armature spring 15
Set the elasticity of According to the setting of the elasticity of the valve spring 14 and the armature spring 15, when the upper surface 27a of the armature 27 comes into contact with the locking surface 11a of the stopper 11, as shown in FIG.
Locking surface 1 of stopper 11 fixed to poppet valve 5
The armature 27 in contact with 1a is integrated with the poppet valve 5 and moves upward with a predetermined initial speed by the inertia force of the armature 27 and the suction force of the solenoid 28 against the elasticity. Lift the poppet valve 5
Is seated on the seating surface 10a of the valve seat member 10, and the poppet valve 5 is closed (period B in FIG. 6). By closing the poppet valve 5, the fuel passage 52 to the plunger chamber 25 and the supply / discharge oil passage 12 are shut off, and the return amount of the fuel becomes 0 (zero).

As a result, the plunger chamber 25 is closed, and the pressure rise in the plunger chamber 25 due to the downward movement of the plunger 1 increases, and the pressure increases in the fuel passage 052.
When the pressure in the oil sump 02 is transmitted to the oil sump 02 and exceeds the valve opening pressure of the needle valve 4 spring 51, the needle valve 4 opens, and the fuel in the oil sump 02 flows from the injection hole 02a into the combustion chamber. Injected into. When the lift of the poppet valve 5 starts, the armature 27 collides with the poppet valve 5 by the movement of only the armature 27 during the period A, so that the initial speed is given to the poppet valve 5. As in the period B shown in FIG. 6, the poppet valve 5 (and the armature 27) can reach the valve-closing lift in a shorter time (higher speed) than the prior art shown in FIG. Therefore, according to this embodiment, the responsiveness of the poppet valve 5 is higher than that of the related art.

According to this embodiment, as described above, when the armature 27 collides with the poppet valve 5, the initial speed is given to the poppet valve 5 and the lift is started. As shown in 1), the time from full opening to full closing of the poppet valve 5 is shorter than the time in the prior art shown in FIG. As a result, the time ta1 during which the passage area is reduced in the poppet valve 5 is reduced.
Is shorter than the time tb1 in the prior art, and therefore, the time ta2 when the fuel injection pressure is high is shorter than the time tb2 in the prior art, and the minimum fuel injection amount when the poppet valve 5 is closed and immediately opened. Can be reduced as compared with the prior art.

Therefore, according to this embodiment, as described above, the responsiveness of the poppet valve 5 can be increased and the minimum fuel injection amount can be reduced as compared with the prior art. Can be controlled stably.

According to this embodiment, since the armature 27 is reciprocally fitted to the stopper 11 fixed to the poppet valve 5, the poppet valve 5 is
When this reciprocates, the valve spring 14 can be rotated by a rotational force applied in the winding direction. Thereby, the annular seat portion 5a of the poppet valve 5
Is rotatable relative to an annular seating surface 10a formed on the valve seat member 10, so that the seat portion 5a and the seating surface 10a can be rotated.
a is prevented from locally causing a strong contact, and is always attached and detached uniformly, so that uneven wear of the seat portion between the poppet valve 5 and the valve seat member 10 is prevented.

In the second embodiment shown in FIGS. 3 and 4, a spool valve 23 is provided instead of the poppet valve 5 in the first embodiment. That is, in FIG.
Is a valve case fixed in the pump case 3 by the fixing screw 015, 23 is a spool valve fitted reciprocally slidably in the valve case 010, and 11 is the spool valve 23.
A cylindrical stopper 15 fixed to the upper part of the armature by a bolt 29, 15 is provided between the upper surface of the armature 27 and the bolt 2
9 is an armature spring composed of a compression spring installed between the lower surface of a shoulder 9 and the lower surface. The elasticity of the armature spring 15 is set smaller than the elasticity of the valve spring 14 by a predetermined amount.

As in the case of the poppet valve 5 in the first embodiment shown in FIG. 1B, the armature 27 has an inner peripheral surface 27b formed on the small-diameter portion outer peripheral surface 11b of the stopper 11.
Are fitted to be able to reciprocate. The armature 27 is pressed against the upper surface 23c of the spool valve 23 by the resilience of the armature spring 15 when the solenoid 28 is de-energized, and the solenoid 28
When the power is supplied to the stopper 11, the upper surface 27a of the armature 27 can move along the outer peripheral surface 11b of the small diameter portion of the stopper 11 until the upper surface 27a of the armature 27 comes into contact with the locking surface 11a formed on the stopper 11 by the attraction force of the solenoid 28. Attached to.

In the valve case 010, a return hole 033 communicating with the plunger chamber 25 through the fuel passage 52 is provided at one location in the axial direction, and the spool valve 23 is provided in the axial direction of the spool valve. Are provided with two continuous circumferential grooves 233 having different depths. That is,
In FIG. 4 showing the details of the groove 233 and the return hole 033, the groove 233 includes an upper groove 233a having a greater depth (a depth a) and a lower groove 233b (a depth b) which is shallower than the upper groove 233a. The grooves 233a and 233b are formed continuously in the axial direction of the spool valve 23.
As the shaft 3 moves in the axial direction, the hole 3 is sequentially hooked on the return hole 033.

In this embodiment, FIG. 3 and FIG.
As shown in (A), the lower end surface 23a of the spool valve 23
In the lowermost position of the spool valve 23 which contacts the bottom surface 3a of the pump case 3, both the upper groove 233a and the lower groove 233b communicate with the return hole 033. As a result, the fuel passage 52 and the plunger chamber 25 are communicated with the oil supply / drain passage 12 through both the upper groove 233a and the lower groove 233b to maximize the fuel return passage area. The fuel in the plunger chamber 25 pushed away by the downward movement of the return hole 033
The fuel is returned to the oil supply / discharge passage 12 through the upper groove 233a and the lower groove 233b, and the fuel injection is not performed.

Next, as shown in FIG. 4 (B), at the intermediate position of the spool valve 23 where the lower end surface 23a of the spool valve 23 rises by a certain amount from the bottom surface 3a, the upper groove 233a is closed, and Only the shallow lower groove 233b communicates with the return hole 033. As a result, a part of the fuel in the plunger chamber 25 pushed away by the downward movement of the plunger 1 becomes the lower groove 23 having a shallow depth and a narrow passage area.
3b, it is returned to the oil supply / discharge passage 12 side. As a result, the fuel injection rate and the fuel injection pressure rise slowly, and the premixed combustion in the early stage of the injection can be suppressed, the rise in the combustion temperature in the combustion chamber is suppressed, and NOx
The amount of (nitrogen oxide) generated is reduced.

Further, as shown in FIG. 4C, at the uppermost position of the spool valve 23 in which the lower end surface 23a of the spool valve 23 is further raised than the intermediate position, the upper groove 233a and the lower groove 233b are formed. Both are closed, the plunger chamber 25 and the oil supply / discharge passage 12 are shut off,
The return amount of the fuel becomes zero (0). As a result, the plunger chamber 25 is closed and the pressure rise increases, the fuel discharged by the plunger 1 is injected into the combustion chamber from the injection hole 02a, and the fuel injection rate and the injection pressure increase. High pressure, large injection quantity injection

According to the second embodiment, one return hole 033 communicating with the plunger chamber 25 is provided, and two continuous circumferential grooves having different depths in the axial direction are formed in the spool valve 23. Since it is sufficient to provide the 233, it is not necessary to process and form the valve seat portion as in the case of the poppet valve 5 in the first embodiment, the structure becomes simpler and the processing cost is reduced.

According to the second embodiment, a grooved spool valve 23 having one end fixed to the armature 27 operated by the solenoid 28 of the solenoid valve device 20 and the return hole 033 are extremely simple. A low-cost device with a small number of parts reduces the amount of NOx generated due to the suppression of premixed combustion by mitigating increases in the fuel injection rate and fuel injection pressure in the early stage of injection, and reduces the amount of fuel in the late stage of injection. It is possible to perform two-stage fuel injection control of high-efficiency combustion in a high-pressure, large-injection-volume injection mode by increasing the injection rate and fuel injection pressure. Other configurations are the same as those of the embodiment shown in FIGS. 1 to 4, and the same members are denoted by the same reference numerals.

[0050]

As described above, according to the present invention, the armature and the on-off valve are connected so as to be relatively movable in the axial direction.
After the armature moves within a certain range in the initial stage of suction of the armature by the stopper mechanism, the armature is caused to collide with the on-off valve, so that the initial speed is given to the on-off valve and a lift is started. Time is shorter than in the prior art. As a result, the time during which the passage area is reduced in the on-off valve portion is reduced as compared with the prior art, and therefore, the time during which the fuel injection pressure increases is shorter than in the prior art, and the on-off valve is closed and immediately opened. It is possible to make the minimum fuel injection amount at the time of the fuel injection smaller than that of the related art.

Therefore, according to the present invention, as described above,
Since the responsiveness of the on-off valve increases and the minimum fuel injection amount can be reduced as compared with the related art, it is possible to control the fuel injection amount up to a low injection region without lowering the control accuracy. As a result, the stable operation range of the engine can be expanded to a low load and low rotation range, the idling speed can be reduced, and low noise and low fuel consumption of the engine during idling operation can be realized.

Further, according to the present invention, since the armature is reciprocally fitted to the stopper mechanism fixed to the poppet valve, the valve is reciprocated when the poppet valve reciprocates. It is possible to rotate by the rotational force given by the spring, whereby the seat portion of the poppet valve and the seat portion of the valve seat member can be relatively rotated, and a strong contact is locally generated in the seat portion. The poppet valve and the valve seat member are prevented from being unevenly worn, and the good sealing performance of the valve seat portion can be maintained for a long time.

Further, according to the present invention, it is possible to combine a return valve with a grooved spool valve having one end fixed to an armature operated by a solenoid of a solenoid valve device. A low-cost device with a low fuel injection rate reduces the amount of NOx generated due to the suppression of premixed combustion by alleviating the rise in fuel injection rate and fuel injection pressure in the early stage of injection, and the fuel injection rate in the late stage of injection. And high pressure due to increased fuel injection pressure,
It is possible to perform two-stage fuel injection control with high-efficiency combustion in the large injection amount injection mode.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the vicinity of a solenoid valve device and a poppet valve in an electronically controlled fuel injection device of a unit injector for a diesel engine according to a first embodiment of the present invention, showing a poppet valve fully opened.

FIGS. 2A and 2B are cross-sectional views showing the vicinity of the solenoid valve device and the poppet valve in the first embodiment, wherein FIG. 2A shows the start of lifting of the poppet valve, and FIG.

FIG. 3 is a view corresponding to FIG. 1, showing a second embodiment.

FIG. 4 is an operation explanatory view showing an enlarged view of the vicinity of a spool valve groove in the second embodiment.

FIG. 5 is a configuration diagram including a cross-sectional view along a plunger center line in the vicinity of an electromagnetic valve device and a sleeve valve in the electronically controlled fuel injection device of the unit injector for the diesel engine according to the first embodiment.

FIG. 6 is an operation explanatory view in the first and second embodiments.

FIG. 7 shows a diagram corresponding to FIG. 2 showing the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plunger 2 Fuel injection nozzle 02a Injection hole 3 Pump case 4 Needle valve 5 Poppet valve 5a Seat surface 6 Tappet 60 Roller 8 Plunger spring 10 Valve seat member 010 Valve case 10a Seat surface 11 Stopper 11a Locking surface 12 Oil supply / drain passage 13 Oil chamber 14 Valve spring 15 Armature spring 16 Valve case 17 Oil chamber 20 Electromagnetic valve device 23 Spool valve 25 Plunger chamber 27 Armature 28 Solenoid 30 Space 31 Valve case 031 Solenoid chamber 033 Passage hole 45 Electromagnetic valve control device 46 Revolution detector 47 Load detector 51 Needle valve spring 52, 052 Fuel passage 54 Rocker arm 57 Push rod 61 Fuel cam 100 Unit injector 101 Fuel injection pump 102 Fuel injection nozzle 233 Groove 233a Upper groove 33b lower groove

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16K 3/24 F16K 3/24 D 31/06 305 31/06 305Z 305L F-term (Reference) 3G060 AB06 AC08 BA19 BC02 CA03 CB03 DA00 DA12 EA00 FA07 3G066 AA07 AB02 AC07 AD12 BA00 BA17 BA19 BA22 BA25 BA46 BA61 CA01S CA04U CA08 CA09 CC06T CC14 CE02 CE24 CE34 DA11 DA12 DA13 DA14 DA16 3H053 AA22 AA35 BA04 DA12 3H106 DA07 DB12 DB23 DD17 EE05 EE22 EE30 EE39 GA15 GA23 GB06 GC02 KK18

Claims (5)

[Claims] An armature which is attracted to the solenoid by energizing a solenoid of a solenoid valve device and which is released by shutting off the energization, and which is reciprocated by being connected to the armature and which reciprocates to suck the armature An on-off valve that is moved in a direction to close the oil supply / discharge passage to the plunger chamber, and a valve spring that urges the on-off valve in the valve opening direction, and changes the timing at which the on-off valve closes the oil supply / discharge passage. An electronically controlled fuel injection device configured to control the fuel injection timing by connecting the armature and the on-off valve so as to be relatively movable in the axial direction of the on-off valve. Only the armature can be moved within the range, and after passing through the certain range, the relative movement between the armature and the on-off valve is locked to open the armature. An electronically controlled fuel injection device comprising a stopper mechanism for integrally moving a valve closing mechanism. 2. An armature spring, which is compressed by the armature when the armature moves within the predetermined range, is interposed between the armature and the on-off valve;
Within the certain range, the armature moves against the elasticity of the armature spring by suction of the solenoid, and after the armature is locked by the stopper mechanism, the armature and the on-off valve are connected to the valve spring. The electronically controlled fuel injection device according to claim 1, wherein the electronically controlled fuel injection device is configured to move against elasticity. 3. The poppet valve according to claim 1, wherein the on-off valve is a poppet valve having an annular seat portion which is attached to and detached from an annular seating surface formed on a valve seat member to open and close the oil supply / drain passage. Item 3. The electronically controlled fuel injection device according to Item 2. 4. A valve case having a passage hole communicating with the oil supply / discharge passage is provided, and the on-off valve comprises a spool valve reciprocated in the valve case to open and close the passage hole. 3. The electronically controlled fuel injection device according to claim 2, wherein: 5. A passage hole in the valve case is provided, and a plurality of continuous circumferential grooves having different depths in an axial direction of the spool valve are provided in the spool valve. In the minimum lift range of the spool valve, all of the plurality of grooves communicate with the passage hole, and as the lift increases, the groove having a smaller depth communicates with the passage hole. The electronically controlled fuel injection device according to claim 4, wherein all of the grooves are configured to close the passage hole.