JPH10238431A - Accumulative fuel injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a leak of operating fuel for opening or closing a nozzle needle in an accumulative fuel injector. SOLUTION: A nozzle needle 18 for controlling fuel injection is fed with or drained of high-pressure operating fuel so as to be opened or closed from the side of a first accumulator 36 with the use of a two-way solenoid valve 100 with almost no risk of a fuel leak and a throttling valve 102. That setup prevents a leak of the high-pressure operating fuel for the needle 18 and thus a leak of fuel to be jetted out, to thereby prevent a degradation in fuel economy of an associated engine through reduced driving force of a fuel pressurization pump 46 and also improve the durability of the pump 46 through resolved insufficient lubrication thereof owing to increased fuel temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accumulator type fuel injection device for a diesel engine.

[0002]

2. Description of the Related Art Various accumulator fuel injection devices for diesel engines have been proposed in Japanese Patent Application Laid-Open No. Hei 6-93936. The configuration of a conventional pressure-accumulation type fuel injection device proposed in Japanese Patent Application Laid-Open No. 6-93936 will be described with reference to FIG. FIG. 6 shows a schematic configuration of a conventional pressure accumulating fuel injection device.

In the pressure accumulating type fuel injection device shown in the figure, pressurized fuel is sent from a fuel pressurizing pump 46 to a first pressure accumulator 36 and a second pressure accumulator 78, and the first pressure accumulator 36 has a high pressure (for example, 800 to 800).
1000 atm) of fuel, and the second pressure accumulator 78
Fuel at a lower pressure (for example, 300 to 500 atm) than the accumulator 36 is stored. First accumulator 36 or second accumulator 78
High-pressure or low-pressure fuel is selectively sent to the fuel reservoir 14, and the high-pressure fuel sent from the first accumulator 36 controls the nozzle needle 18 to inject the high-pressure or low-pressure fuel sent to the fuel reservoir 14. .

When the fuel injection nozzle 10 is not operated, the electromagnetic actuator 90 of the second three-way solenoid valve 86 is deenergized, the second inlet z communicates with the outlet y, and the low-pressure fuel in the second accumulator 78 is discharged. It is supplied to the reservoir 14. On the other hand, the first three-way solenoid valve 3
The fourth electromagnetic actuator 40 is deenergized and the entrance a and the first
The outlet b is communicated, and the high-pressure fuel of the first pressure accumulator 36 is supplied to the oil chamber 26. Therefore, the nozzle needle 18 is kept in the closed state.

At the time of fuel injection, the electromagnetic actuator 40 of the first three-way solenoid valve 34 is energized to make the first outlet b and the second outlet c communicate for a short time, and the fuel pressure in the oil chamber 26 is removed. As a result, the nozzle needle 18 is opened for a short time against the urging force of the pressure spring 24, and the low-pressure fuel in the fuel reservoir 14 is injected into the cylinder from the fuel injection hole 12 (pilot injection).

After the pilot injection, the second three-way solenoid valve 86
Is energized to communicate the first inlet x and the outlet y, and the high pressure fuel in the first pressure accumulator 36 is supplied to the fuel reservoir 14. Subsequently, the electromagnetic actuator 40 of the first three-way solenoid valve 34 is energized to communicate the first outlet b and the second outlet c for a predetermined time, and the fuel pressure in the oil chamber 26 is removed. As a result, the nozzle needle 18 is opened for a predetermined time against the urging force of the pressure spring 24, and the high-pressure fuel in the fuel reservoir 14 is injected into the cylinder from the fuel injection hole 12 (main injection).

[0007] In the above-mentioned conventional accumulator type fuel injection device,
One injection cycle is completed by two-stage injection of pilot injection and main injection. For this reason, moderate combustion is performed, the operating noise and vibration of the engine are reduced, and the exhaust gas performance is improved.

[0008]

In the pressure accumulating fuel injection device described above, the opening and closing of the nozzle needle 18 is controlled by increasing and decreasing the pressure of high-pressure fuel on the back surface of the hydraulic piston 28. One three-way solenoid valve 34 is used. However, since the first three-way solenoid valve 34 has two high-pressure seal portions having a valve function, there is a possibility that leakage of high-pressure fuel may occur unless a reliable seal is provided.

If the leakage of the high-pressure fuel occurs and the amount of the leakage increases, the driving loss of the fuel pressurizing pump 46 is caused and the fuel efficiency of the engine is deteriorated. Further, since the high-pressure leak fuel has a high temperature (for example, 120 to 140 ° C.), an increase in the leak fuel causes an increase in the fuel temperature in the fuel tank, and a problem such as poor lubrication of the fuel pressurizing pump 46 due to a decrease in fuel viscosity. Will occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a pressure accumulating fuel injection device capable of suppressing leakage of operating fuel of a nozzle needle for controlling fuel injection.

[0011]

In order to achieve the above object, the present invention provides a first pressure accumulator for storing fuel at a predetermined pressure, and a first pressure accumulator having a lower pressure than the fuel in the first pressure accumulator. A second pressure accumulator for storing fuel, a fuel pressurizing pump for supplying pressurized fuel to the first pressure accumulator and the second pressure accumulator, and a nozzle needle for controlling fuel injection by opening and closing. A fuel injection nozzle, a throttle member provided in a passage communicating the nozzle needle with the first pressure accumulator or the second pressure accumulator, and a fuel in the first pressure accumulator via the throttle member to the nozzle needle. A two-way solenoid valve that closes the nozzle needle by applying pressure or fuel pressure in the second accumulator, and opens the nozzle needle by removing the fuel pressure; Wherein the fuel reservoir of the fuel injection nozzle first
A three-way solenoid valve for selectively communicating the pressure accumulator or the second pressure accumulator with the two-way solenoid valve after the second pressure accumulator and the fuel reservoir are first communicated by the three-way solenoid valve during fuel injection The pilot pressure of a small amount of fuel is performed by removing the fuel pressure of the first pressure accumulator or the second pressure accumulator applied to the nozzle needle for a short time, and then the first pressure accumulation is performed by the three-way solenoid valve. After the reservoir and the fuel reservoir are communicated with each other, the fuel pressure of the first pressure accumulator or the second pressure accumulator applied to the nozzle needle by the two-way solenoid valve is removed for a predetermined time, so that the remaining fuel can be maintained. A controller is provided for controlling the three-way solenoid valve and the two-way solenoid valve so that injection is performed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic configuration of an accumulator type fuel injection device according to a first embodiment of the present invention, FIG. 2 shows a fuel injection pattern, and FIGS. 3 and 4 show heat generation patterns. It is. The same members as those of the conventional pressure accumulating fuel injection device shown in FIG. 6 are denoted by the same reference numerals.

As shown in FIG. 1, a fuel injection hole 12 is formed at the tip of a fuel injection nozzle 10, and a nozzle 16 having a fuel reservoir 14 for storing fuel supplied to the fuel injection hole 12 is provided. The injection nozzle 10 is provided. A nozzle needle 18 for controlling the communication between the fuel reservoir 14 and the fuel injection hole 12 is slidably housed in the nozzle 16, and the nozzle needle 18 is moved through a push rod 22 housed in the nozzle holder 20 through a pressure spring 24. Thus, it is normally biased in the closing direction. An oil chamber 26 is formed in the nozzle holder 20, and a hydraulic piston 28 is slidably fitted in the oil chamber 26 coaxially with the nozzle needle 18 and the push rod 22.

A first accumulator 36 for storing high-pressure (for example, 800 to 1000 atm) fuel is provided, and a second accumulator for storing lower-pressure (for example, 300 to 500 atm) fuel than the first accumulator 36 is provided. An accumulator 78 is provided. The first pressure accumulator 36 is provided with a fuel pressure sensor 74 for detecting the fuel pressure in the first pressure accumulator 36, and the second pressure accumulator 78 is provided with a fuel pressure sensor 84 for detecting the fuel pressure in the second pressure accumulator 78. Is provided.

The fuel injection nozzle 10 is provided with a second three-way solenoid valve 86 as a three-way solenoid valve for supplying fuel to the fuel reservoir 14. The first inlet x of the second three-way solenoid valve 86 is connected to the upstream feed hole 44a, and the upstream feed hole 44a communicates with the oil passage 105 on the first accumulator 36 side. The second inlet z of the second three-way solenoid valve 86 is the second
It is connected to the accumulator 78. The second three-way solenoid valve 8
6 is connected to the downstream feed hole 44b, and the downstream feed hole 44b communicates with the fuel reservoir 14. The second three-way solenoid valve 86 includes a valve body 88 for selectively connecting one of the first inlet x or the second inlet z to the outlet y, and an electromagnetic actuator 90 for switching the valve body 88. ing. Electromagnetic actuator 9
0 is drive-controlled by the controller 66.

The first pressure accumulator 36 and the second pressure accumulator 78 include:
High-pressure fuel set in advance according to the operating state of the engine is supplied by the fuel pressurizing pump 46. That is, the first
The pressure accumulator 36 is connected to the fuel pressurizing pump 46 via an oil passage 80, and is connected to the second accumulator 36 via an oil passage 80 a branched from the oil passage 80.
An accumulator 78 is connected to the fuel pressurizing pump 46. The oil passage 80a is provided with an electromagnetic on-off valve 82, and the electromagnetic on-off valve 8
2 is opened and closed based on a command from the controller 66 according to the operating state of the engine. By opening and closing the electromagnetic on-off valve 82, the fuel pressure in the second accumulator 78 is adjusted to the set pressure.

On the other hand, an oil passage 105 on the side of the first accumulator 36 communicates with the oil chamber 26, and a throttle valve 102 as a throttle member is provided in a part of the oil passage 105. An oil passage 106 branches from an oil passage 105 between the throttle valve 102 and the oil chamber 26, and a second throttle valve 103 is provided in the oil passage 106. The oil passage 106 is connected to the fuel tank 38 via a two-way solenoid valve 100, and the fuel flow of the two-way solenoid valve 100 is controlled by an electromagnetic actuator 101.

The second pressure accumulator 78 has a fuel tank 38.
Is provided with a drain oil passage 109 leading to the drain oil passage 1
09 is provided with an electromagnetic on-off valve 110. The opening and closing of the electromagnetic on-off valve 110 is controlled by the controller 66, and when the fuel pressure detected by the fuel pressure sensor 84 becomes equal to or higher than a predetermined value, the electromagnetic on-off valve 110 is driven to open. Thus, even if high-pressure fuel leaks from the second three-way solenoid valve 86, the leaked fuel is recovered by the second pressure accumulator 78, and the pressure in the second pressure accumulator 78 is reduced by the fuel pressure sensor 84. When the pressure increases, the electromagnetic on-off valve 110 is driven to open, and the pressure inside the second accumulator 78 does not become unnecessarily high due to the recovered fuel.

The above-described fuel pressurizing pump 46 is an eccentric wheel or cam 48 driven in conjunction with the crankshaft of the engine.
The plunger 50 is reciprocally driven by the plunger 50.
The oil in the fuel tank 38 supplied into the tank 4 is pressurized and sent to the oil passage 80 through the one-way valve 56. Pump room 54
A spill valve 64 is interposed between the suction pump 60 and the suction side passage 60 communicating with the feed pump 52, and the spill valve 64 is opened and closed by an electromagnetic actuator 62. The drive of the electromagnetic actuator 62 is controlled by a controller 66.

The controller 66 includes a cylinder discriminating device 68 for discriminating individual cylinders of the multi-cylinder engine, an engine speed and crank angle detecting device 70, an engine load detecting device 72, a fuel pressure sensor 74, and a fuel pressure sensor 8.
4, the electromagnetic actuator 62, the electromagnetic actuator 9 based on auxiliary information 76 such as air temperature, atmospheric pressure, fuel temperature, etc., which affect the operating state of the engine as necessary.
0, controls the electromagnetic actuator 101, the electromagnetic switching valve 82, and the electromagnetic switching valve 110.

The operation of the pressure-accumulation type fuel injection device having the above configuration will be described.

First, the plunger 50 is driven by an eccentric wheel or cam 48 driven in conjunction with the crankshaft of the engine. It is pumped to the path 80. The controller 66 according to the operating state of the engine
The spill valve 64 is opened and closed, and the fuel pressure in the first accumulator 36 is set to a predetermined high pressure (for example, 800).
~ 1000 atm). In addition, a drive command is output from the controller 66 to the electromagnetic on-off valve 82 in accordance with the operation state of the engine, and the electromagnetic on-off valve 82 is opened and closed, and the fuel pressure in the second accumulator 78 is set to a predetermined pressure (for example, 300
~ 500 atm). The pressures in the first pressure accumulator 36 and the second pressure accumulator 78 are detected by the fuel pressure sensors 74 and 84 and fed back to the controller 66.

The high-pressure fuel in the first accumulator 36 is supplied to the oil passage 10
5 through the throttle valve 102 to the oil chamber 26, and together with the urging force of the pressure spring 24,
8 is pressed downward (always biased in the closing direction). The fuel supplied to the oil chamber 26 via the throttle valve 102 is further throttled by the second throttle valve 103 and stored in an oil passage 106 connected to the two-way solenoid valve 100.

When the fuel injection nozzle 10 is not operated, the controller 66 deactivates the electromagnetic actuator 90 of the second three-way solenoid valve 86, and the second inlet z on the second accumulator 78 side.
Communicates with the outlet y on the downstream side feed hole 44b side,
The low-pressure fuel in the second pressure accumulator 78 is supplied to the fuel reservoir 14.

At this time, the hydraulic piston 28 in the oil chamber 26 is pressed downward by the high-pressure fuel from the first accumulator 36, and the pressure spring 24
Is applied to the nozzle needle 18 via the push rod 22. At this time, the pressure receiving area of the high pressure fuel acting downward on the hydraulic piston 28 is set to be larger than the pressure acting area of the low pressure fuel or high pressure fuel acting upward on the nozzle needle 18,
In addition, since the urging force of the pressure spring 24 acts, the nozzle needle 18 is reliably held at the closed position.

At the time of fuel injection, the electromagnetic actuator 101 of the two-way solenoid valve 100 is energized by the controller 66 to connect the oil passage 106 to the fuel tank 38, and the throttle valve 1
Due to 02, the pressure of the oil passage 106 becomes lower than that of the oil passage 105 (a pressure difference occurs), and the fuel pressure in the oil chamber 26 is removed. As a result, the nozzle needle 18 is opened against the urging force of the pressure spring 24, the low-pressure fuel in the fuel reservoir 14 is injected into the cylinder from the fuel injection hole 12, and the vertical axis indicates the fuel injection rate dq / dθ. The pilot injection indicated by _Ip in FIG. 2 in which the horizontal axis indicates the crank angle θ is performed.

After a very short time, that is, after a lapse of the crank angle θ ₁ , actually, after an instant, the electromagnetic actuator 101 of the two-way solenoid valve 100 is deenergized by the controller 66 and the oil passage 106 is disconnected from the fuel tank 38. Then, the high-pressure fuel is supplied into the oil chamber 26 again. As a result, the nozzle needle 18 is closed, and the pilot injection _Ip is stopped.

During the crank angle θ ₂ shown in FIG. 3, the controller 66 urges the electromagnetic actuator 90 of the second three-way solenoid valve 86 to connect the first inlet x of the upstream feed hole 44a on the first pressure accumulator 36 side with the first inlet x. Downstream feed hole 44b
And the outlet y on the side. Thereby, the first accumulator 3
6 is supplied to the fuel reservoir 14. Subsequently, the electromagnetic actuator 101 of the two-way solenoid valve 100 is urged by the controller 66 to connect the oil passage 106 to the fuel tank 38, and the throttle valve 102 lowers the oil passage 106 with respect to the oil passage 105 (pressure). The fuel pressure in the oil chamber 26 is relieved (due to the difference). As a result, the nozzle needle 18 is opened against the urging force of the pressure spring 24, the high-pressure fuel in the fuel reservoir 14 is injected into the cylinder from the fuel injection hole 12, and the main injection indicated by _Im in FIG. Done.

After a lapse of time corresponding to the crank angle θ ₃ , the electromagnetic actuator 101 of the two-way solenoid valve 100 is deenergized by the controller 66, the oil passage 106 is disconnected from the fuel tank 38, and the high pressure is again introduced into the oil chamber 26. Fuel is supplied. Thus, the nozzle needle 18 is closed, 1 injection cycle by pilot injection I _p and the main injection I _m is completed.

In the above-described pressure-accumulation type fuel injection device, a small amount (for example, about 10% of the total injection amount) of the low-pressure fuel is used for each fuel injection cycle during the first short crank angle θ _1.
It performs a pilot injection I _p, crank angle of the pause time θ
After a _2, and to perform the main injection I _m by the high-pressure fuel over the crank angle theta ₃ a relatively long time. Thus, a small amount of fuel of the pilot injection I _p is immediately without combustion, so that the gradual combustion is caused with the high-pressure fuel injected early in the main injection I _m.

[0031] Therefore, as for Q ₁ of heat generation pattern of FIG. 3 showing taking crank angle θ to the horizontal axis represents the heat generation rate dQ / d [theta] to the longitudinal axis, the maximum pressure and temperature is relatively low Combustion occurs. Therefore, the lower the vibration and noise of the engine, and the less _the amount of NO _X in the exhaust gas, an improved combustion can be improved engine performance. Incidentally, in a conventional fuel injection device that does not perform pilot injection I _p, as indicated by Q ₀ of the heat generation pattern of FIG. 4, the rapid explosive combustion at high temperature and high pressure is carried out, with the operating noise of the engine is increased There is a problem that the NO _X amount in the exhaust gas increases.

In the above-described accumulator type fuel injection device,
The two-way solenoid valve 100 and the throttle valve 102, which have little risk of fuel leakage, supply and discharge high-pressure fuel into the oil chamber 26 to open and close the nozzle needle 18, so that fuel injection is controlled. Leakage of operating fuel from the nozzle needle 18 can be suppressed. Further, since the high-pressure fuel of the first pressure accumulator 36 is used as the operating fuel for the nozzle needle 18, the responsiveness is excellent, and the two-stage injection of a desired pattern can be reliably executed as intended.

By suppressing the fuel leakage, the driving force of the fuel pressurizing pump 46 is reduced and the deterioration of the fuel efficiency of the engine is suppressed, and the lubrication failure of the fuel pressurizing pump 46 due to the rise of the fuel temperature is eliminated, and the fuel supply is prevented. The durability of the pressure pump 46 is improved.

In the embodiment shown in FIG. 1, the second throttle valve 103 is provided in the oil passage 106 so as to suppress the wave of the fuel pressure fluctuation in the fuel reservoir 14. Of the nozzle needle 18 by adjusting the urging force of the
If the closing force can be sufficiently secured, the second throttle valve 103 does not necessarily need to be provided.

A second embodiment of the present invention will be described with reference to FIG. FIG. 5 shows a schematic configuration of a pressure accumulating fuel injection device according to a second embodiment of the present invention. The accumulator type fuel injection device according to the present embodiment is provided with the second accumulator 7 as the working fuel for supplying to the oil chamber 26 and closing the nozzle needle 18.
8 uses the low-pressure fuel, and the other configuration is the same as the accumulator-type fuel injection device shown in FIG. For this reason, the same members as those shown in FIG. 1 are denoted by the same reference numerals, and overlapping description is omitted.

An oil passage 107 is provided in the oil passage 80a connecting the fuel pressurizing pump 46 and the second accumulator 78, branching from the downstream side of the electromagnetic on-off valve 82, and the oil passage 107 communicates with the oil chamber 26. I have. A throttle valve 102 as a throttle member is provided at an intermediate portion of the oil passage 107, and an oil passage 108 is provided branching from the oil passage 107 between the throttle valve 102 and the oil chamber 26. The oil passage 108 is provided with a second throttle valve 103, and the oil passage 108 is connected to the fuel tank 38 via a two-way solenoid valve 100. The fuel flow of the two-way solenoid valve 100 is controlled by an electromagnetic actuator 101. The first pressure accumulator 36 is connected to the first inlet x of the second three-way solenoid valve 86 by the upstream feed hole 44a.

The low-pressure fuel (second pressure accumulator 78) sent from the fuel pressurizing pump 46 to the oil passage 107 through the electromagnetic opening / closing valve 82
Side) is supplied to the oil chamber 26 through the throttle valve 102, and presses the hydraulic piston 28 downward in accordance with the urging force of the pressure spring 24 (is normally urged in the closing direction). The fuel supplied to the oil chamber 26 via the throttle valve 102 is further throttled by the second throttle valve 103 and stored in an oil passage 108 connected to the two-way solenoid valve 100.

The first accumulator 36 is operated by the second three-way solenoid valve 86.
The high-pressure fuel in the tank or the low-pressure fuel in the second accumulator 78 is supplied to the fuel reservoir 14. Further, the hydraulic piston 28 in the oil chamber 26 is pressed downward by the low-pressure fuel from the second accumulator 78 side, and the valve closing force obtained by adding the urging force of the pressure spring 24 to this depressing force is the push rod 2.
2 is applied to the nozzle needle 18. At this time,
The pressure receiving area of the low pressure fuel acting downward on the hydraulic piston 28 is set to be sufficiently larger than the pressure acting area of the low pressure fuel or high pressure fuel acting upward on the nozzle needle 18, and the urging force of the pressure spring 24. Is set large, the nozzle needle 18 is kept closed by the low-pressure fuel supplied to the oil chamber 26 even when the high-pressure fuel is supplied to the fuel reservoir 14.

At the time of fuel injection, the electromagnetic actuator 101 of the two-way solenoid valve 100 is energized by the controller 66 to connect the oil passage 108 to the fuel tank 38, and the throttle valve 1
Due to 02, the pressure of the oil passage 108 becomes lower than that of the oil passage 107 (a pressure difference occurs), and the fuel pressure in the oil chamber 26 is removed. As a result, the nozzle needle 18 is opened against the urging force of the pressure spring 24, and the low-pressure fuel or high-pressure fuel in the fuel reservoir 14 is injected into the cylinder from the fuel injection hole 12, and pilot injection or main injection is performed. . Thereafter, the electromagnetic actuator 101 of the two-way solenoid valve 100 is deenergized by the controller 66 and the oil passage 1
08 is shut off from the fuel tank 38, and low-pressure fuel is supplied into the oil chamber 26 again. Thereby, the nozzle needle 18
Is closed, and the pilot injection or the main injection is stopped.

In the above-described accumulator type fuel injection device, as in the case of the accumulator type fuel injection device shown in FIG. 1, gradual combustion is performed by two-stage injection consisting of pilot injection and main injection, and engine operation noise and vibration Is reduced, the NO _X amount in the exhaust gas is reduced, and the main injection is performed by high-pressure fuel to improve combustion, thereby improving engine performance.

In the above-described accumulator type fuel injection device,
The nozzle needle 18 is opened and closed by supplying and discharging low-pressure fuel from the second pressure accumulator 78 into the oil chamber 26 using the two-way solenoid valve 100 and the throttle valve 102 that have little risk of fuel leakage. . For this reason, it is possible to reliably suppress the leakage of the operating fuel of the nozzle needle 18 that controls the fuel injection. Therefore, since the fuel leakage is reliably suppressed, the driving force of the fuel pressurizing pump 46 is surely reduced to suppress the deterioration of the fuel efficiency of the engine, and the lubrication failure of the fuel pressurizing pump 46 due to the fuel temperature rise is reduced. It is completely eliminated and the durability of the fuel pressurizing pump 46 is improved.

[0042]

Accumulator fuel injection device of the present invention exhibits excellent engine performance such as output and fuel consumption, and to reduce the amount of NO _X in the noise and vibration and exhaust gas, particularly, suitable vehicular diesel engine It can be a fuel injection device. The two-way solenoid valve and the throttle valve, which have almost no risk of fuel leakage, control the fuel injection using the two-way solenoid valve. Leakage of the working fuel can be suppressed. As a result, the fuel leakage is suppressed, the driving force of the fuel pressurizing pump is reduced, and the deterioration of the fuel efficiency of the engine is suppressed. Durability is improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a pressure accumulating fuel injection device according to a first embodiment of the present invention.

FIG. 2 is a graph showing a fuel injection pattern.

FIG. 3 is a graph showing a heat generation pattern.

FIG. 4 is a graph showing a heat generation pattern.

FIG. 5 is a schematic configuration diagram of a pressure accumulating fuel injection device according to a second embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a conventional accumulator type fuel injection device.

[Explanation of symbols]

 Reference Signs List 10 fuel injection nozzle 12 fuel injection hole 14 fuel reservoir 18 nozzle needle 22 push rod 24 pressure spring 26 oil chamber 28 hydraulic piston 36 first pressure accumulator 38 fuel tank 46 fuel pressurizing pump 66 controller 78 second pressure accumulator 86 second three way Solenoid valve 100 Two-way solenoid valve 102 Throttle valve 103 Second throttle valve 105 Oil passage 106 Oil passage 107 Oil passage 108 Oil passage

Claims (1)

[Claims] A first pressure accumulator for storing fuel at a predetermined pressure; a second pressure accumulator for storing fuel at a pressure lower than the fuel in the first pressure accumulator; A fuel pressurizing pump for supplying the first pressure accumulator and the second pressure accumulator, a fuel injection nozzle having a nozzle needle for controlling fuel injection by opening and closing, a fuel injection nozzle, the nozzle needle and the first pressure accumulator or the first pressure accumulator. 2
A throttle member provided in a passage communicating with the pressure accumulator; and the nozzle nozzle by applying a fuel pressure on the first pressure accumulator side or a fuel pressure on the second pressure accumulator side to the nozzle needle via the throttle member. A two-way solenoid valve that closes the needle and opens the nozzle needle by removing the fuel pressure, and selectively connects the fuel reservoir of the fuel injection nozzle and the first accumulator or the second accumulator. A three-way solenoid valve that communicates with the first pressure accumulator that is applied to the nozzle needle by the two-way solenoid valve after the second pressure accumulator and the fuel reservoir are first communicated by the three-way solenoid valve during fuel injection; The pilot pressure of a small amount of fuel is performed by removing the fuel pressure on the pressure side or the second pressure accumulator side for a short time, and thereafter the first fuel pressure is reduced by the three-way solenoid valve. After the pressurizer and the fuel reservoir are communicated with each other, the fuel pressure on the first pressure accumulator side or the second pressure accumulator side applied to the nozzle needle by the two-way solenoid valve is removed for a predetermined time, so that the remaining fuel is removed. And a controller that controls the three-way solenoid valve and the two-way solenoid valve so that the main injection is performed.