JPH04284160A - Unit injector - Google Patents

Abstract

PURPOSE:To avoid the dispersion of the fuel injection quantity in each time by permitting the nearly normal operation of an engine by avoiding the fuel injection in fuel quantity adjustment when a solenoid-operated timing control valve fails in a valve opening state. CONSTITUTION:A quantity adjusting plunger 6 is fitted in slidable manner with a quantity adjusting plunger bore 21 in relation to a fuel spin port 24, and a forced feed pump chamber 17 is formed in a forced feed plunger bore 16, and an injection pump chamber 22 is formed in a quantity adjusting plunger bore 21. When a solenoid-operated timing control valve 5 operates normally, pumping operation is carried out by the pressure in the forced feed pump chamber which is increased by the forced feed plunger 4, and when the valve 5 fails in a valve opening state, pupming operation is carried out directly by the forced feed plunger. Further, a hydraulic damper is combined with the forced feed plunger side edge of the quantity adjusting plunger, and the movement of the forced feed plunger is transmitted to the quantity adjusting plunger.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a unit injector equipped with a solenoid operated timing control valve for use in internal combustion engines.

0002

BACKGROUND ART In this type of unit injector, if the solenoid operated timing control valve fails to open, the metering plunger reaches its maximum lift, and thereafter, injection is performed during metering. In this case, the metering timing was set well before the normal injection timing, so the engine torque could not be produced.

In addition, in this type of unit injector, at the end of fuel injection, the fuel spill port is connected to the pressure pump chamber just before the end of the stroke of the metering plunger, and high-pressure working oil is pumped through the fuel spill port. Since the fuel is leaked from the pump chamber to the reservoir and the metering plunger is pushed in by the residual pressure of the working oil, the fuel spill port is opened when the inner peripheral surface of the metering plunger bore is machined. Width accuracy control is extremely difficult,
There was variation in the amount of injection.

0004

[Problem of the Invention] An object of this invention is to avoid fuel injection during fuel metering when the solenoid operated timing control valve fails to open, thereby allowing the internal combustion engine to operate almost normally. The unit injector is provided.

Another object of the present invention is to provide a unit injector that avoids variations in fuel injection amount each time due to the opening width accuracy of a fuel spill port on the inner circumferential surface of a metering plunger bore.

[0006]

Means for the Problem and Operation Thereof The present invention provides a system in which a metering plunger is reciprocally slidably fitted into a metering plunger bore in association with a fuel spill port to provide a pressure pump chamber to the pressure plunger bore. An injection pump chamber is formed in each metering plunger bore, and when the solenoid-operated timing control valve is operated normally, the pressure inside the pressure-feeding pump chamber is increased by the pressure-feeding plunger, and the solenoid-operated timing control valve is pumped. When the timed timing control valve fails to open, it is directly pumped by its pressure-feeding plunger.

[0007] The present invention also provides a method in which the metering plunger is reciprocatingly slidably fitted into the metering plunger bore in association with the fuel spill port to provide a pressure pump chamber to the metering plunger bore. When the solenoid-operated timing control valve is operated normally, the pressure inside the pressure-feeding pump chamber is increased by the pressure-feeding plunger, and the solenoid-operated timing control valve is opened. When the valve fails, in addition to being pumped by the pressure-feeding plunger, a hydraulic damper is combined with the pressure-feeding plunger side end of the metering plunger so as to be able to reciprocate in the axial direction,
When the metering plunger communicates the fuel spill port with the pressure pump chamber, the movement of the pressure plunger is transmitted to the metering plunger by the pressure generated inside by being pushed by the pressure plunger. It is in.

[0008]

DESCRIPTION OF EMBODIMENTS FIG. 1 schematically shows a specific embodiment 1 of a unit injector of the present invention applied to an automobile diesel engine. This unit injector 1 includes a valve body 2, a nozzle needle 3, a pressure-feeding plunger 4, a solenoid-operated timing control valve 5, a metering plunger 6,
It was assembled including a follower 7, a valve spring 8, and a check valve 9.

The valve body 2 has a valve seat 11
and a needle spindle bore 10 with injection ports 12, 13, and a pump plunger bore 16 with pump oil spill ports 18, 19 and injection timing ports 20.
is coaxially continuous with the pumping plunger bore 16 on the needle spindle bore 10 side with a fuel inlet port 23 and a fuel spill port 24, and has a fuel inlet port 23 and a fuel spill port 24 coaxially continuous with the pumping plunger bore 16 on the needle spindle bore 10 side; A metering plunger bore 21 is formed in which the port 23 is connected to the fuel passage 15, and then, as usual, it is divided into a plurality of blocks, and the blocks are sequentially butted together and assembled integrally with nuts (not shown). It was done.

[0010] Also, this valve body 2 has a shoulder 2
5, extending the guide sleeve 26 coaxially into the pumping plunger bore 16,
6 guides its follower 7 and valve spring 8. Of course, the shoulder 25 provides a spring seat for the valve spring 8. moreover,
The valve body 2 is located below the shoulder 25 and has a pump port 27 opened on its outer peripheral surface, and the pump port 27 is connected to the fuel inlet port 23 through a fuel passage 28 inside. . Furthermore, in this valve body 2, the fuel spill port 24 and the forced oil spill port 19 are connected to each other as a shared spill port 29 and are opened on the outer peripheral surface. Of course, the pressure-feeding oil spill port 18 and the fuel spill port 24 were opened into ring grooves on the inner circumferential surface of the pressure-feeding plunger bore 16 and the metering plunger bore 21, respectively.

The nozzle needle 3 is fitted into the needle spindle bore 10 so as to be able to slide back and forth, and is seated on the valve seat 11 by a needle spring 30. Of course, the needle spindle bore 10 into which the nozzle needle 3 was fitted was formed in the nozzle of the valve body 2 like a normal unit injector.

The pumping plunger 4 is reciprocally slidably disposed in the pumping plunger bore 16 so as to open the pumping oil spill ports 18, 19 at maximum lift, and is cooperated with the metering plunger 6. A pressure pump chamber 17 is formed within the pressure plunger bore 16. In addition, this pressure-feeding plunger 4 has a stud 31 extending on its upper end surface and is flange-grooved to its follower 7, so that the follower 7 cooperates with its valve spring 8 and is connected to a camshaft (not shown). When driven by a fixedly supported cam (not shown), its follower 7 causes a reciprocating sliding, so-called pumping, movement in its pumping plunger bore 16.

The solenoid operated timing control valve 5 includes a valve body 32 fixedly assembled to the valve body 2, a ball poppet 35 fitted into a valve bore 33 of the valve body 32, and a valve seat of the valve bore 33. Valve spring 37 that seats the ball poppet 35 on 34
, a push rod 36 that pushes the ball poppet 35 against the valve spring 37, and a solenoid coil 38 that drives the push rod 36.

The valve body 32 has a valve bore 33 formed therein and a rod guide bore 39 coaxially communicating with the valve bore 33, as shown in the drawings. A structure was adopted in which the push rod 36 was guided by the push rod 36. Further, this valve body 32 has a rod guide bore 39
The valve seat 34 is formed at a location where the valve seat 34 is connected to the valve bore 33, and the inlet port 40 and the rod guide bore 3 are connected to the valve bore 33.
An outlet port 41 communicating with 9 was formed. Of course, when the valve body 32 is bolted to the valve body 2, the inlet port 40 and the outlet port 41 are aligned with the injection timing port 20 and the pressurized oil spill port 19, and are connected to the pressurized oil spill port. The timing control valve 5 is connected between the injection timing port 19 and the injection timing port 20.

The solenoid coil 38 is electrically connected to a control unit (not shown) and is energized by the output current of the control unit to drive the push rod 36 and drive the push rod 36.
6, connect the ball poppet 35 to the valve spring 3.
Have them press against 7. Of course, the control unit determines the output current depending on the speed of the diesel engine and the accelerator pedal (not shown) for the diesel engine, and directs the output current to the solenoid coil 38.

The metering plunger 6 is reciprocally slidably fitted in the metering plunger bore 21 in association with the fuel spill port 24 and is cooperated with the pumping plunger 4 to open the pumping plunger bore. A pressure pump chamber 17 is formed in the metering plunger bore 21, and an injection pump chamber 22 is formed in the metering plunger bore 21.
A pumping operation is performed to pressurize the fuel to high pressure and inject it into the combustion chamber (not shown) of the diesel engine from the injection ports 12 and 13. In this case, the metering plunger 6
The length is such that when the solenoid operated timing control valve 5 is operated normally, it is pumped by the pressure in the pressure pump chamber 17 that is increased by the pressure plunger 4, and the solenoid operated timing The control valve 5 was sized so that it would be pumped directly by its pressure plunger 4 if it were to fail in the open state as shown.

More specifically, the length of the metering plunger 6 is such that when the timing control valve 5 fails to open, the metering plunger 6 is lifted by the pressure-feeding plunger 4. It is set in relation to the length of the pumping plunger 4 and the position of the fuel spill port 24 so that it is pushed directly from the middle of the pump. Therefore, the timing control valve 5
Fuel injection in the event of a failure in the open condition is such that the metering plunger 6 is pushed directly by the pumping plunger 4 to close the fuel spill port 24 and then up to the maximum lift of the pumping plunger 4. The maximum amount of fuel to be injected at this time is determined by the stroke from when the metering plunger 6 closes the fuel spill port 24 to the maximum lift of the pressure-feeding plunger 4 that is directly moved by the pressure-feeding plunger 4. As a result, by adjusting the lengths of the metering plunger 6 and the pressure-feeding plunger 4, the timing at which the metering plunger 6 contacts the pressure-feeding plunger 4 can be freely changed; in other words, it can be freely set. .

The check valve 9 is disposed in the fuel passage 28 which communicates the pump port 27 with the fuel inlet port 23, and has a ball poppet 45 fitted into a valve bore 43 formed in the middle of the fuel passage 28.
and a valve seat 44 formed in the valve bore 43.
and a valve spring 46 that seats the ball poppet 45 and prevents backflow of fuel from the injection pump chamber 22 to the pump port 27.

The unit injector 1 constructed as described above is disposed in the cylinder head (not shown) of the diesel engine and is driven by the camshaft attached to the cylinder head. Of course, the unit injector 1 has its pump port 27 connected to a fuel pipe (not shown) and a metering pump (not shown).
, the shared spill ports 29 are respectively connected to the return side of a fuel tank (not shown) by fuel return piping (not shown), and the timing control valve 5 is connected to the output circuit of the control unit by its solenoid coil. 38 is electrically connected and used in the diesel engine.

Next, to explain the operation of the unit injector 1, first, when the timing control valve 5 is normal, fuel is sent from the metering pump to the pump port 27 via the fuel pipe. Flows into the fuel passage 28, and on the way, the check valve 9
is opened and the fuel is sent from its inlet port 23 to its injection pump chamber 22. At this time, the control unit determines the output current that corresponds to the injection timing according to the rotation speed and load of the diesel engine (accelerator pedal depression amount), and sends that output current to the solenoid coil 38. Therefore, the solenoid coil 38 is energized and the push rod 36 is driven.
The ball poppet 35 is pushed away from the valve seat 34 by the push rod 36 against the valve spring 37. That is, at this time, the timing control valve 5 is placed in the open state and the injection timing port 20 is connected to the pressurized oil spill port 19 through the timing control valve 5, so that the oil is sent to the injection pump chamber 22. The metering plunger 6 is pushed up by the amount of fuel consumed.

Since the camshaft is being rotated, the follower 7 is pushed against the valve spring by the cam of the camshaft, and the pressure-feeding plunger 4 is also pushed accordingly. In this way, the pressure-feeding plunger 4 is pushed in and the pressure-feeding oil spill port 18 is closed, but since the timing control valve 5 is kept open,
The fuel in the pressure pump chamber 17 is not yet compressed, and the amount of fuel corresponding to the pressure of the pressure plunger 4 passes through the injection timing port 20 and the pressure oil spill ports 19 and 18 to the pressure pump chamber. 17 into its fuel tank, its metering plunger 6 being maintained in its metering position in its metering plunger bore 21.

Since the injection timing is determined when the pressure-feeding plunger 4 is in the process of being continuously pushed in, the control unit controls the current flowing through the solenoid coil 38 at the determined injection timing. is turned off to demagnetize the solenoid coil 38. When the solenoid coil 38 is demagnetized, the ball poppet 35 is seated on the valve seat 34 by the valve spring 37 and the timing control valve 5 is closed, so that the pressure pump chamber 1
The fuel in the injection pump chamber 22 begins to be compressed and a pressure builds up in the pressure pump chamber 17, which pressure pushes down the metering plunger 6, compressing the fuel in the injection pump chamber 22 and increasing the pressure. When the injection pump chamber 22 is raised, the fuel in the fuel reservoir 14, which is in communication with the injection pump chamber 22 through the fuel passage 15, lifts the nozzle needle 3 against the needle spring 30, and the injection ports 12, 13 and is injected into the combustion chamber (not shown) of the diesel engine. In this way, in this unit injector 1, fuel injection is started, and the injected fuel is mixed with intake air in the combustion chamber and ignited.

Subsequently, the pressure-feeding plunger 4 is pushed down, so the metering plunger 6 is also pushed down further, and fuel injection continues from the nozzles 12 and 13.
Then, in the combustion chamber, explosive combustion occurs. Immediately before the metering plunger 6 is pushed out by the pressure in the pressure pump chamber 17, the shoulder 42 of the metering plunger 6 overlaps the fuel spill port 24, and the fuel in the pressure pump chamber 17 is The fuel is leaked into the fuel tank via the fuel spill port 24, and the pressure in the so-called pressure pump chamber 17 is released, so the pressure in the fuel reservoir 14 is reduced, and accordingly, the nozzle needle 3 is again pressed against the valve seat 11 by the needle spring 30, the injection ports 12 and 13 are closed, and fuel injection is terminated.

In this way, this unit injector 1 repeatedly injects fuel according to the rotational speed and load of the diesel engine.
When the timing control valve 5 is faulted to the open position as shown, the metering plunger
The fuel is metered as described above, with the injection timing port and the pressure oil spill port communicating with each other so that the fuel in the pressure pump chamber can freely escape into the fuel tank, and the pressure plunger 4 is pushed in, the fuel is not compressed in the pressure pump chamber 17, in other words, the pressure is not increased, so the metering plunger 6 is directly pushed in by the pressure feed plunger 4. That is, the metering plunger 6 is directly pumped by the pumping plunger 4. In this case, after the fuel spill port 24 is closed by the metering plunger 6, the fuel metered into the metering pump chamber 22 is compressed by the metering plunger 6, and the pressure is equal to The fuel is transmitted to the fuel reservoir 14 via the passage 15. Then, the nozzle needle 3 is lifted against the needle spring 30 to open the nozzle ports 12 and 13, and the fuel is injected from the nozzle ports 12 and 13 into the combustion chamber of the diesel engine, and then mixed into the intake air. and burned.

Even in the case of such a failure, the unit injector 1 injects fuel up to the maximum lift of the pressure-feeding plunger 4 as described above. In this case, the fuel injection timing is slightly delayed compared to the normal one, and the engine torque is also slightly lower than the normal one, so that the vehicle can avoid road failure. .

FIG. 2 shows schematically another specified embodiment 50 of the unit injector of the invention applied to a diesel engine of a motor vehicle. This unit injector 50 is the same as the unit injector 1 described above, but the metering plunger 6 is modified to provide a hydraulic damper 52.
is added, and its valve body 2, nozzle needle 3, pressure feed plunger 4, solenoid operated timing control valve 5, metering plunger 51
, hydraulic damper 52, follower 7, valve spring 8,
And, it was assembled including the check valve 9. Of course, the components of this unit injector 50 that correspond to those of the unit injector 1 are given the same reference numerals.

The metering plunger 51 has a structure in which a spindle 53 is coaxially extended at the end of the pressure-feeding plunger, and a shoulder 54 is formed at the end of the pressure-feeding plunger. Similarly to the metering plunger 6 of the unit injector 1 described above, the metering plunger 51 is reciprocally slidably fitted into the metering plunger bore 21 in relation to the fuel spill port 24, and is connected to the pressure-feeding plunger. A pressure pump chamber 17 is formed in the bore 16 and an injection pump chamber 22 is formed in the metering plunger bore 21. When the solenoid-operated timing control valve 5 is operated normally, the pressure feed plunger 4 is When the solenoid-operated timing control valve 5 fails to open, the pumping operation is performed by the pressure in the pressure pump chamber 17 via the hydraulic damper 52. be done. In addition, in order to ensure such a pumping operation, the shoulder 54 is configured so that the metering plunger 51 leaves a slight stroke just before the metering plunger 51 is pushed completely and the pressure-feeding plunger 4 reaches its full stroke. It was set in such a way that it was in contact with the hydraulic damper 52 and overlapped with the fuel spill port 24, so that the pressure in the pressure pump chamber 17 was released.

The hydraulic damper 52 includes a cylinder 55 and a coil spring 61, and the metering plunger 5
It was combined with the side end of the pressure-feeding plunger of No. 1 so as to be able to reciprocate and slide in the axial direction. The cylinder 55 has an end wall 56 at one end.
The metering plunger 51 is closed at the other end and opened at the other end, and is fitted into the spindle 53 of the metering plunger 51 so as to be able to reciprocate and slide, and cooperated with the spindle 53 to form a cylinder chamber 58 inside. It was done. that cylinder 5
5 also connects the cylinder chamber 58 to the pressure pump chamber 1.
7 to allow oil (fuel) to flow between the cylinder chamber 58 and the pressure pump chamber 17, and the suction port 59 is opened and closed by the pressure plunger 4. is formed in its end wall 56 such that its orifice 6
0 was formed on the side wall 57. Further, the coil spring 61 is arranged in the cylinder chamber 58 so as to be able to expand and contract in the axial direction of the cylinder 55.

Next, to explain the operation of the unit injector 50, the unit injector 50 is operated in such a manner that the action of the hydraulic damper 52 is added to the operation of the unit injector 1 described above. Of course, the action of the hydraulic damper 52 also affects the operation of the unit injector 1 when the solenoid operated timing control valve 5 is normal.
The same applies to the operation of the unit injector 1 when the unit injector 1 fails to open its valve. Now, if the timing control valve 5 is normal, the fuel is sent to the injection pump chamber 22 by the metering pump, and the metering plunger 51 is raised into the metering plunger bore 21 accordingly. is metered into its injection pump chamber 22. For fuel metering, the camshaft is rotated, so the follower 7 is synchronized with the camshaft, and the cam fixedly supported on the camshaft acts against the valve spring 8. It is pushed in, and the pressure-feeding plunger 4 is also pushed in accordingly. Even if the pressure-feeding plunger 4 closes the pressure-feeding oil spill port 18, the fuel in the pressure-feeding pump chamber 17 is not compressed by the pressure-feeding plunger 4 while the timing control valve 5 is open. , the metering plunger 51 is maintained in the metering position in the metering plunger bore 21 so that the so-called pressure is applied to the metering plunger 5.
1, fuel injection will not start.

The injection timing is determined by the control unit according to the rotation speed and load of the diesel engine, and the injection timing is determined by the control unit according to the rotation speed and load of the diesel engine.
is set after closing the pressure oil spill port 18, so when the solenoid operated timing control valve 5 is closed at the injection timing determined by the control unit, the fuel in the pressure pump chamber 17 is The pressure in the pressure pump chamber 17 begins to be compressed by the pressure feed plunger 4, and the pressure is increased in the pressure feed pump chamber 17.
The pressure is transmitted to the metering plunger 51. In that way, the metering plunger 51 is pushed down with the pressure into the metering plunger bore 21, so that the fuel metered into the injection pump chamber 22 is compressed, and the pressure increases in the fuel passage 15. The nozzle needle 3 is lifted up against the needle spring 30, and the fuel is injected from the injection ports 12 and 13 into the combustion chamber of the diesel engine.

[0031] The fuel injection is carried out continuously from the start, and explosive combustion occurs in the combustion chamber. Immediately before the metering plunger 51 is pushed out by the pressure inside the pressure pump chamber 17, the metering plunger 51
The shoulder 54 overlaps the fuel spill port 24, and the fuel in the pressure pump chamber 17 is released to the fuel tank through the fuel spill port 24, and the pressure in the pressure pump chamber 17 is released. . At this time,
The metering plunger 51 has a slight stroke left, but the pressure plunger 4 contacts the cylinder 55 of the hydraulic damper 52 and pushes the cylinder 55, and the suction port 59 is closed by the pressure plunger 4. and in this state, the cylinder 55 is pushed by the pressure plunger 4, so that the fuel in the cylinder chamber 58 flows out into the pressure pump chamber 17 through the orifice 60, and at this time, the fuel in the cylinder chamber 58 flows out through the orifice 60 and into the pressure pump chamber 17. With the pressure generated, the stroke of the pressure-feeding plunger 4 is transmitted to the metering plunger 51, and the metering plunger 51
is pushed through.

[0032] In that way, the metering plunger 51
When the pressure is pushed out, the fuel injection is terminated, and when the pressure plunger 4 leaves the cylinder 55 for the next fuel injection, the fuel flows from the pressure pump chamber 17 through the suction port 59 to the cylinder chamber. 58, and the hydraulic damper 52 is restored by the coil spring 61. As such, this unit injector 5
0, the force that pushes out the metering plunger 51 is set by the orifice 60, so it is easier to control the accuracy of processing compared to a normal unit injector, which depends on the opening width of the fuel spill port, and Variations in fuel injection amount were reliably suppressed.

Further, when the solenoid operated timing control valve 5 fails to open, the metering plunger 51 is pushed by the pressure-feeding plunger 4 via the hydraulic damper 52, and the unit injector 1 described above is pressed. It operates similarly to the pumping action. In this case as well, fuel injection is performed up to the maximum lift of the pressure-feeding plunger 4, so the fuel injection timing is only slightly delayed from the normal one, and the engine torque is also slightly lower than the normal one. The vehicle was able to avoid a road failure condition.

[0034]

BENEFITS OF THE INVENTION As can be seen from the foregoing, the unit injector of the present invention has a metering plunger reciprocatingly slidably fitted into a metering plunger bore in relation to a fuel spill port, and a pumping plunger bore. A pressure pump chamber is formed in cooperation with the pressure plunger, and an injection pump chamber is formed in the metering plunger bore. When the solenoid operated timing control valve fails to open, the pressure oil spill port is opened. Immediately after being closed by the pressure-feeding plunger, the pumping operation is performed directly by the pressure-feeding plunger, so if the timing control valve breaks down,
Fuel injection is avoided during fuel metering, the fuel injection timing is slightly delayed from the normal one, and the engine torque is also slightly reduced from the normal one, and in this way, The internal combustion engine will be able to operate almost normally, and the road failure situation will be avoided in the car, making it very useful and practical for the car.

Further, in the unit injector of the present invention, the hydraulic damper is combined with the pressure-feeding plunger side end of the metering plunger so as to be slidable back and forth in the axial direction, and the metering plunger communicates the fuel spill port with the pressure-feeding pump chamber. At this time, the movement of the pressure-feeding plunger is transmitted to the metering plunger by the pressure generated inside when it is pushed by the pressure-feeding plunger, so the force that pushes the metering plunger completely is set by the orifice of the hydraulic damper. This makes it easier to control the accuracy of processing compared to a normal unit injector due to the opening width of the fuel spill port, and it reliably suppresses variations in the amount of fuel injected each time. If the valve fails to open, its metering plunger is pumped by its pressure-feeding plunger through its hydraulic damper, so fuel injection is avoided during fuel metering, and the fuel injection timing is changed from normal. The engine torque is also slightly reduced compared to its normal state, thus allowing the internal combustion engine to operate almost normally, and in the car. , the road failure situation is avoided, which makes it very useful and practical for cars.

As mentioned above, from the specific examples of the present invention explained with reference to the drawings, various design modifications and changes will be easily made by those who have ordinary knowledge in the technical field to which this invention pertains. Furthermore, the content of the invention is essential to the establishment of the invention that accomplishes the task of the invention, and originates from the technical essence of the invention, which is the nature of the invention, and If it is internalized, it can be easily replaced with an objectively recognized aspect.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a specific example of a unit injector of the present invention applied to an automobile diesel engine.

FIG. 2 is a longitudinal sectional view showing another specific example of the unit injector of the present invention applied to an automobile diesel engine.

[Explanation of symbols]

1 Unit injector 2 Valve body 3 Nozzle needle 4 Pressure plunger 5 Solenoid operated timing control valve 6 Metering plunger 17 Pressure pump chamber 18 Pressure oil spill port 19 Pressure oil spill port 20 Injection timing port 22 Injection pump chamber 24 Fuel spill port 50 Unit injector 51 Metering plunger 52 Hydraulic damper 53 Spindle 55 Cylinder 59 Suction port 60 Orifice 61 Coil spring

Claims (2)

[Claims] 1. A needle spindle bore having a valve seat and an injection port, a pumping plunger bore having a pumping oil spill port and an injection timing port, and a pumping plunger bore having a fuel inlet port and a fuel spill port, on the needle spindle bore side thereof. a valve body comprising a metering plunger bore coaxially continuous with the pressure-feeding plunger bore and communicating its fuel inlet port side with the fuel reservoir of the needle spindle bore; and a needle spring fitted into the needle spindle bore. a nozzle needle seated on its valve seat, a pressure plunger that is reciprocally slidably fitted in its pressure plunger bore in relation to its pressure oil spill port, and its pressure oil spill port and injection timing port; a solenoid-operated timing control valve that is reciprocatingly slidably fitted in its metering plunger bore in conjunction with its fuel spill port to pump a pump chamber in its metering plunger bore; If the pump chamber is respectively formed and its solenoid operated timing control valve is operated normally,
The pressure in the pressure pump chamber is increased by the pressure plunger, and if the solenoid operated timing control valve fails to open, the control valve is pumped directly by the pressure plunger. A unit injector containing a volume plunger and. 2. A needle spindle bore having a valve seat and an injection port, a pumping plunger bore having a pumping oil spill port and an injection timing port, and a fuel inlet port and a fuel spill port on the needle spindle bore side thereof. a valve body comprising a metering plunger bore coaxially continuous with the pressure-feeding plunger bore and communicating its fuel inlet port side with the fuel reservoir of the needle spindle bore; and a needle spring fitted into the needle spindle bore. a nozzle needle seated on its valve seat, a pressure plunger that is reciprocally slidably fitted in its pressure plunger bore in relation to its pressure oil spill port, and its pressure oil spill port and injection timing port; a solenoid-operated timing control valve that is reciprocatingly slidably fitted in its metering plunger bore in conjunction with its fuel spill port to pump a pump chamber in its metering plunger bore; If the pump chamber is respectively formed and its solenoid operated timing control valve is operated normally,
The metering plunger is pumped by the pressure in the pressure pump chamber that is increased by the pressure plunger, and if the solenoid operated timing control valve fails to open, the metering plunger is pumped by the pressure plunger. , is axially reciprocally slidably associated with the pressure-feeding plunger side end of the metering plunger, and is pushed by the pressure-feeding plunger when the metering plunger communicates the fuel spill port with the pressure-feeding pump chamber. and a hydraulic damper which transmits the movement of its pumping plunger to its metering plunger with pressure generated internally.