JP3651188B2 - Fuel injection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection device, and more particularly to a pressure accumulation fuel injection device used for a diesel engine.
[0002]
[Prior art]
Generally, a pressure accumulation type (common rail type) fuel injection device introduces high-pressure fuel supplied from a pressure accumulation chamber into a control chamber provided inside the fuel injection valve, and lowers the needle valve of the fuel control valve. The needle valve is kept in a normally closed state, and the fuel in the control chamber is leaked to the fuel discharge passage, and the pressure in the control chamber is reduced to raise the needle valve. The needle valve is opened and fuel is injected from the fuel injection hole. It is the structure to do.
[0003]
In such a conventional fuel injection device, the fuel injection rate depends on the valve opening at the tip of the needle valve and the size of the valve hole.
That is, in the process of raising the needle valve and opening the flow path to the fuel injection hole, while the flow path area is smaller than the fuel injection hole, the fuel injection rate is defined by the flow path area, After the flow passage area becomes larger than the cross-sectional area of the fuel injection hole, the fuel injection rate is defined by the cross-sectional area of the fuel injection hole.
[0004]
Further, the flow passage cross-sectional area (A) of the fuel to the control chamber and the flow passage cross-sectional area (B) of the fuel exiting the control chamber are usually fixed at A: B = 2: 3 or 1: 2, respectively. ing. Therefore, the lift speed of the needle valve increases at a constant speed, and the fuel injection rate has the characteristics shown by the solid line (a) or (b) in FIG.
[0005]
[Problems to be solved by the invention]
However, in a diesel engine, it is effective to keep the initial fuel injection amount low and increase the injection rate in the second half in order to achieve combustion noise, NOx reduction, engine full load performance, and PM reduction simultaneously. . PM is an abbreviation for particulate matter, and is a general term for tar-like unburned substances including sulfur oxides.
[0006]
In response to such a demand, as in the conventional example, a fuel injection device in which the flow passage cross-sectional area (A) of the fuel to the control chamber and the flow passage cross-sectional area (B) of the fuel exiting the control chamber are fixed Then, there is no freedom in selecting the injection rate.
[0007]
That is, in the conventional apparatus, when the IN channel cross-sectional area (A) is made smaller than the OUT channel cross-sectional area (B), the needle valve lift speed becomes steep as shown in FIG. When the fuel injection rate at the initial stage of the fuel is increased and the flow passage cross-sectional area (A) of IN is made larger than the flow passage cross-sectional area (B) of OUT, as shown in FIG. The fuel injection rate at the initial stage of the fuel gradually increases and the fuel injection rate rises gradually, so that the fuel injection time is increased accordingly.
[0008]
Therefore, within this range, the ratio of the flow path cross-sectional area (A) of IN and the flow path cross-sectional area (B) of OUT is selected, and the gradient in which the fuel injection rate increases is selected. Therefore, it is impossible to realize a fuel injection rate that gradually begins and then rises steeply as shown in FIG. 7C.
[0009]
By the way, Japanese Patent Application Laid-Open No. 5-71438 proposes a fuel injection device that controls a low injection rate at the initial stage of fuel injection and a high injection rate at a later stage of injection.
In this device, the pressure in the control chamber that holds the back pressure acting on the nozzle needle that opens and closes the fuel injection hole of the fuel injection valve is switched by a switching valve and the fuel return path (fuel discharge path) In the fuel injection device that controls the switching to the low pressure chamber on the side of the road) and injects fuel from the fuel injection hole, the fuel injection device is arranged in series with the low pressure side of the switching valve, and the flow of the fuel on the low pressure side A control valve that takes at least three states: a first state to be shut off; a second state in which a part of the low-pressure side fuel is allowed to escape; and a third state in which the low-pressure side fuel is completely allowed to escape; When there is no injection, the switching valve is set to the high pressure side and the control valve is set to the first state. At the initial stage of injection, the switching valve is switched to the low pressure side, and at the same time, the control valve is set to the second state. Switch the valve to the low pressure side. In a configuration in which a control device for the control valve and the third state.
[0010]
Here, the control valve described in the publication is a spool valve that is driven by application of a voltage to the piezo element. The relationship between the fuel injection time and the injection amount determined in accordance with the fuel pressure (fuel supply pressure) is stored in the form of a map in advance, and a fuel pressure detection signal in the fuel pressure accumulating chamber is sent to the control device. By being input, the control device controls the switching valve and the spool valve in accordance with the fuel pressure. At the initial stage of injection, the control valve is switched to the low pressure side, and at the same time, the control valve is set to the second state, and the fuel discharge path The discharge flow rate is set to be smaller than the original one, and thereby the pressure in the control chamber is slightly reduced and the nozzle needle is slightly raised to lower the fuel injection rate from the fuel injection hole. Thereafter, by setting the third state, the pressure in the control chamber is completely released, the nozzle needle is completely raised, and a high injection rate is achieved.
[0011]
However, such a device requires a drive source (power supply) such as a piezo element, a map for controlling the drive source, and the like, which increases the cost.
This invention makes it a subject to provide the change with a freedom degree of a fuel injection rate by an inexpensive structure in view of such a point.
[0012]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems. That is, the fuel injection device of the present invention pushes the valve body with the pressure of the high-pressure fuel introduced into the control chamber to close the fuel injection hole, discharges the high-pressure fuel in the control chamber, and lowers the pressure of the valve body. In the fuel injection device having a fuel injection valve that opens an injection hole, the control chamber has a fuel introduction port for introducing high-pressure fuel, and the valve body has a piston that receives fuel pressure in the control chamber. The piston interferes with the fuel introduction port of the control chamber, and sequentially reduces the amount of fuel flowing into the control chamber by decreasing the passage cross-sectional area of the fuel introduction port as the piston rises. It is characterized by that.
[0013]
In the initial stage of fuel injection, the piston has not yet interfered with the fuel introduction port of the control chamber or has interfered slightly. That is, since the fuel introduction port is greatly opened, even if the fuel in the control chamber flows out, the amount of fuel entering the control chamber from the fuel introduction port is large, so that the rising speed of the piston can be kept low. That is, the fuel injection rate increases gradually. After that, when the piston rises and the passage cross-sectional area of the fuel introduction port decreases, the amount of fuel flowing into the control chamber decreases, so the pressure in the control chamber decreases rapidly, and the lift speed of the piston and the valve body increases rapidly. The fuel injection rate increases rapidly.
[0014]
Here, in order to sequentially reduce the passage cross-sectional area of the fuel introduction port as the piston rises, a groove or a groove extending from the fuel introduction port to the control chamber is formed at a portion of the piston that interferes with the fuel introduction port. It is preferable to provide a fuel passage composed of holes.
[0015]
Thereby, the passage cross-sectional area between the fuel introduction port and the fuel passage gradually decreases as the piston rises.
The fuel injection valve includes a fuel injection hole, a valve body that closes the fuel injection hole, an urging means that urges the valve body in a normally closed direction, and a high pressure supplied from a fuel supply source at a predetermined pressure. A first fuel supply passage for guiding fuel to the fuel injection hole; a fuel reservoir for receiving fuel supplied from the first fuel supply passage and applying fuel pressure to the valve body in a valve opening direction; and a fuel supply source A control chamber that receives high pressure fuel supplied at a predetermined pressure from the pressure chamber and presses the valve body in a normally closed direction, a fuel discharge passage that discharges high pressure fuel in the control chamber to lower the hydraulic pressure in the control chamber, and a control chamber It is common to have a back pressure control valve which is interposed in the fuel discharge path from the engine and which contains high-pressure fuel in the control chamber when closed, and allows the fuel to escape from the control chamber to the fuel discharge path when opened.
[0016]
In such a fuel injection valve, when the back pressure control valve is closed, the fuel pressure applied to the control chamber rises. At that time, the pressure that the valve body receives from the fuel pressure in the control chamber is Fm, and the valve body If Fs is the pressing force received from the fuel pressure in the fuel reservoir and Fc is the urging force of the urging means, Fm + Fc> Fs and Fc <Fs, and the fuel injection hole is closed by the valve body. On the other hand, when the back pressure control valve is opened and the fuel is allowed to escape from the control chamber to the fuel discharge passage, the fuel pressure in the control chamber decreases. Therefore, when Fm + Fc <Fs, the urging force of the urging means is increased. The valve body is lifted against this, the fuel injection hole is opened, and fuel injection is started.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0018]
<Overall configuration of device>
FIG. 1 shows the overall configuration of the fuel injection device. This apparatus pumps fuel from a fuel tank 1 that is a fuel supply source and sends it at a predetermined pressure, receives a fuel pump 2 (rotary supply pump) and fuel sent from the fuel pump 2, and receives a predetermined supply pressure. A fuel accumulator chamber 3 for accumulating pressure is provided.
[0019]
A plurality of fuel supply passages 4 are connected to the fuel accumulator chamber 3, and a plurality of fuel injection valves 5 attached to the internal combustion engine are connected to each fuel supply passage 4. When the internal combustion engine is, for example, 6 cylinders and one fuel injection valve 5 is provided for each cylinder, the number of fuel supply passages 4 and the number of fuel injection valves 5 are 6, respectively.
[0020]
The fuel pressure accumulation chamber 3 is provided with a fuel pressure sensor 6 for detecting the fuel pressure in the fuel pressure accumulation chamber 3. Further, the fuel pressure sensor 6 is connected to a control device 7 composed of a computer.
[0021]
The control device 7 includes an accelerator sensor S1 that detects whether or not the accelerator pedal is depressed, an intake pressure sensor S2 that detects intake pressure to the internal combustion engine, and a water temperature sensor that detects the temperature of cooling water in the internal combustion engine. S3, an engine speed sensor (NE sensor) S4 for detecting the rotational speed of the internal combustion engine, an aero flow meter S5 for detecting the amount of air sucked into the internal combustion engine, a G sensor S6 for detecting an inertial force applied to the vehicle, vehicle control, etc. Various sensors required for the are connected.
[0022]
In addition, the control device 7 is provided with a fuel pump drive control unit 8 and a fuel injection valve drive control unit 9, which are configured according to operating conditions determined based on information from the various sensors. The injection valve 5 is driven and controlled.
[0023]
In the control device 7, the fuel pressure in the fuel pressure accumulation chamber 3 is feedback-controlled so as to become a preset target pressure for steady operation. That is, a drive signal is sent to the fuel pump 2 until the detected pressure from the fuel pressure sensor 6 reaches the target pressure, fuel supply is continued, and when the target pressure is reached, the fuel pump 2 is driven. Repeat the control to stop.
[0024]
The fuel pressure accumulation chamber 3 includes a relief valve that releases and releases the pressure in the fuel pressure accumulation chamber 3 when the pressure in the fuel pressure accumulation chamber 3 reaches a predetermined set pressure that exceeds the target pressure. 11 is provided. The relief valve 11 is installed in the form of being interposed in the fuel release path 12 connected to the fuel supply source side, that is, the fuel tank 1.
[0025]
<Fuel injection valve>
As shown in FIG. 2, the fuel injection valve 5 is provided with a cylindrical main body 22 having a fuel injection hole 21 at the tip thereof, and is provided inside the cylindrical main body 22 so as to be movable forward and backward. A needle-like needle valve 23 (valve element) that closes 21 and opens the fuel injection hole 21 when retreating, and a coil spring 24 as an urging means that urges the needle valve 23 in the normally open direction are provided. .
[0026]
Further, the fuel injection valve 5 includes a first fuel supply path 31 that guides the high-pressure fuel supplied from the pressure accumulating chamber 3 that is a fuel supply source at a predetermined pressure to the fuel injection hole 21 and the needle that receives the high-pressure fuel. A control chamber 32 that presses the valve 23 in the normally closed direction, and high-pressure fuel that branches from the first fuel supply passage 31 and is supplied at a predetermined pressure from a pressure accumulating chamber that is a fuel supply source to the control chamber 32. A second fuel supply passage 33 is provided, and a fuel discharge passage 34 that discharges the high-pressure fuel in the control chamber 32 to lower the hydraulic pressure in the control chamber 32.
[0027]
Secondly, the outlet of the fuel supply passage 33 to the control chamber 32 is a fuel inlet referred to in the present invention, and the flow rate of fuel to the control chamber 32 is determined as the inlet orifice 33a. An entrance to the fuel discharge path 34 is an outlet orifice 34a that determines the flow rate of fuel out of the control chamber 32. The ratio of the passage sectional area of the inlet orifice 33a and the outlet orifice 34a is set to 2.5: 3.
[0028]
The needle valve 23 has a main piston 23a that faces the control chamber 32 and lowers the needle valve 23 under the fuel pressure in the control chamber 32. The main piston 23a is a fuel introduction port. The passage sectional area of the inlet orifice 33a is changed by moving up and down by interfering with a certain inlet orifice 33a.
[0029]
Further, in order to facilitate the change in the passage cross-sectional area, a fuel passage 32b extending from the inlet orifice 33a (fuel inlet) into the control chamber 32 is formed at the portion of the main piston 23a corresponding to the inlet orifice 33a. ing. The fuel passage 32b is formed by providing an oblique cutout groove 23b as shown in FIG. 2 and a through hole shown in FIG. 3 in a part of the main piston 23a. When such a fuel passage 32b is provided, the piston lift is such that the passage sectional area between the inlet orifice 33a and the inlet of the fuel passage 32b continuously and arbitrarily decreases as the main piston 23a rises. Each inlet orifice area can be set.
[0030]
FIG. 3 shows the structure around the control chamber 32 shown in FIG. 2 in principle, and the basic structure is the same as FIG.
The needle valve 23 is provided with a sub-piston 23 c on the fuel injection hole 21 side of the needle valve 23 with respect to the main piston 23 a facing the control chamber 32. A fuel reservoir 31a is provided in the middle of the first fuel supply path 31 leading to the fuel injection hole 21 so as to face the sub-piston 23c. For this reason, the fuel pressure in the fuel reservoir 31a is applied to the sub-piston 23c, pushing the needle valve 23 in the opening direction (upward in the figure). The pressure receiving area Ss where the sub piston 23c receives the fuel pressure in the fuel reservoir 31a is set smaller than the pressure receiving area Sm where the main piston 23a receives the fuel pressure in the control chamber 32. Further, the coil spring 24 for urging the needle valve 23 in the valve closing direction is disposed on the main piston 23a side of the sub piston 23c.
[0031]
The pressing force received by the main piston 23a from the fuel pressure in the control chamber 32 is Fm, the pressing force received by the sub-piston 23c from the fuel pressure in the fuel reservoir 31a is Fs, and the biasing force of the coil spring 24 is Fc. In the steady state, Fm + Fc> Fs and Fc <Fs.
[0032]
Further, a normally closed back pressure control valve 35 is interposed in the fuel discharge passage 34 from the control chamber 32 and contains high-pressure fuel in the control chamber 32 when closed, and allows fuel to escape from the control chamber 32 to the fuel discharge passage 34 when opened. Is provided. The back pressure control valve 35 is a two-way valve that is formed of an electromagnetic valve and is driven and controlled to be in a fully open state or a fully closed state. When the back pressure control valve 35 is closed, the fuel pressure applied to the control chamber 32 rises, and the main piston 23a is pushed by the pressure, and the needle is resisted against the urging force of the spring 24. The valve 23 is lowered.
[0033]
At that time, the fuel having the same pressure as that applied to the fuel chamber 31a from the first fuel supply path 31 is also introduced into the control chamber 32 and pushes the sub-piston 23c, but the pressing force Fs is against Fm + Fc. Since this cannot be done, the needle valve 23 is held in a state where the fuel injection hole 21 is closed.
[0034]
Thereafter, when the back pressure control valve 35 is opened, the fuel in the control chamber 32 is discharged from the fuel discharge passage 34. At this time, the outlet orifice 34a is set larger than the inlet orifice 33a. The amount of fuel outflow from the control chamber is greater than the amount of fuel flowing into the control chamber, and as a result, the fuel pressure in the control chamber 32 decreases.
[0035]
When Fm + Fc <Fs, the needle valve 23 is lifted against the urging force of the spring 24, the fuel injection hole 21 is opened, and fuel injection is started.
Next, the relationship between the fuel injection hole 21 and the needle valve 23 is shown in detail in FIG. The inner wall of the fuel injection hole 21 forming the valve seat is formed in a tapered shape, and the tip of the needle valve 23 has a tapered conical shape. Due to such a shape, when the passage area Sp formed when the needle valve 23 is lifted and separated from the inner wall surface which is the valve seat is smaller than the cross-sectional area Sf of the fuel injection hole 21, the fuel is caused by the passage area. After the injection rate is determined and the needle valve 23 is further lifted and the passage area Sp becomes larger than the cross-sectional area of the fuel injection hole 21, the fuel injection rate is determined by the cross-sectional area of the fuel injection hole 21.
[0036]
<Fuel injection valve drive control>
The fuel injection valve drive control is performed by the fuel injection valve drive control unit 9.
In a diesel engine, fuel injection is performed in a predetermined amount from a compression stroke to an expansion stroke at a predetermined crank angle of the engine, for example, 10 ° CA (crank angle) before top dead center to 5 ° CA after top dead center. When the injection start timing is set to 10 ° CA before top dead center, the fuel injection time is added to this to obtain the injection end timing.
[0037]
Before the fuel injection, the back pressure control valve 35 is closed by the fuel injection valve drive control unit 9, so that the inside of the control chamber 32 is high-pressure fuel introduced from the pressure accumulation chamber through the second fuel supply path 33. Since the pressure is satisfied and the main piston 23a of the needle valve 23 is pushed in the downward direction by the pressure, and the spring 24 also urges the needle valve 23 in the downward direction, the fuel injection hole 21 is closed.
[0038]
When the fuel injection timing comes, the back pressure control valve 35 is opened by the command from the fuel injection valve drive control unit 9, and the high-pressure fuel in the control chamber 32 is discharged from the fuel discharge path 34. As a result, the fuel pressure in the control chamber 32 is lowered, and the needle valve 23 is lifted and the fuel injection hole 21 is opened by the fuel pressure in the fuel reservoir 31a received by the sub-piston 23c. Initially, the fuel injection rate is determined by the passage sectional area Sp around the fuel injection hole 21 until the fuel injection hole 21 is completely opened. When the passage cross-sectional area Sp around the fuel injection hole 21 is larger than the cross-sectional area of the fuel injection hole 21, the fuel injection hole 21 is fully opened.
[0039]
Thereafter, when a predetermined fuel injection time has elapsed, the fuel injection valve drive control unit 9 closes the back pressure control valve 35. Then, since the high-pressure fuel flows into the control chamber 32 and is sealed, the pressure in the control chamber 32 rises, the needle valve 23 descends in response to this pressure, and the fuel injection hole 21 closes.
[0040]
During this period, the main piston 23a interferes with the inlet orifice 33a, and the passage cross-sectional area of the inlet orifice 33a decreases as the main piston 23a rises. To do.
[0041]
In FIG. 5, the portion shown by the solid line is fixed at a ratio of the passage cross-sectional area of the inlet orifice 33a and the outlet orifice 34a of 2: 3 as in the conventional device, and the main piston 23a does not interfere with the inlet orifice 33a. Is the case.
[0042]
On the other hand, in the apparatus according to the present invention, the characteristics are indicated by broken lines.
First, when the back pressure control valve is opened, that is, at the initial stage of fuel injection, the main piston 23 a has not yet interfered with the inlet orifice 33 a of the control chamber 32. Alternatively, even if there is interference, the fuel passage 32b completely coincides with the inlet orifice 33a, the inlet orifice 33a is 100% open, and the ratio of the passage sectional area of the inlet orifice 33a and outlet orifice 34a is 2 .5: 3. Therefore, even if the fuel in the control chamber 32 flows out, the amount of fuel entering the control chamber 32 from the inlet orifice 33a is large. Therefore, the ascending speed of the main piston 23a is kept low. Moreover, since the cross-sectional area is larger by 0.5 on the inlet orifice 33a side as compared with the case of the ratio of 2: 3 as in the prior art, as shown in FIG. The amount of inflow increases, and the rising speed of the main piston 23a becomes slow as shown in FIG. 5 (f). Therefore, the rise of the fuel injection rate becomes slow as shown in FIG. 5 (g) between T1-T2. .
[0043]
Thereafter, when the fuel in the control chamber 32 flows out and the main piston 23a rises and the cross-sectional area of the inlet orifice 33a decreases, the amount of fuel flowing into the control chamber 32 decreases. As shown in FIG. 5 (f) between T2 and T3, the lift speed of the main piston 23a and the needle valve is rapidly increased, and the fuel injection rate is increased as shown in FIG. 5 (g) between T2 and T3. It rises rapidly.
[0044]
As described above, the passage cross-sectional area of the inlet orifice 33a is reduced as the main piston 23a is raised, so that it is possible to control the start-up of the steep fuel injection rate. Is possible. That is, as described above, it is possible to control the IN side to have a larger ratio than before, such as IN: OUT is 2.5: 3.
In this case, since the fuel injection rate can be kept low at the initial stage as described above, combustion noise can be reduced, NOx can be reduced, and excessive increase in in-cylinder pressure due to excessive fuel injection can be suppressed. Moreover, even if the fuel injection rate is kept low at an early stage, the fuel injection rate can be rapidly increased thereafter, so that the injection period can be shortened and the full load performance is improved.
[0045]
Further, if the injection period is made equal, the injection hole area of the fuel injection hole can be reduced, and PM can be reduced.
[0046]
<Variable control area according to this case>
The fuel injection control according to the present case is applicable to the entire range from the low speed range to the high speed range of the engine as shown in FIG. In FIG. 6, in the region indicated by V, the initial injection is set to a low injection rate, and then a high injection rate with a steep rise is set later, and the injection timing can be advanced.
[0047]
The region P is a portion where the stability of the pilot injection amount is required. The pilot injection is a fuel injection for injecting a small amount of fuel in advance and making an appropriate fire type prior to the original injection. In this case, since the initial fuel injection rate can be reduced, it is possible to perform appropriate injection control also in this pilot injection.
[0048]
【The invention's effect】
According to the present invention, the passage cross-sectional area of the fuel introduction port is sequentially decreased as the piston rises, so that the amount of fuel entering the control chamber from the fuel introduction port at the initial stage of fuel injection is increased. The piston rise speed is kept low, the fuel injection rate is kept low, and then the passage cross-sectional area of the fuel inlet is reduced as the piston rises, and the amount of fuel flowing into the control chamber is reduced. It is possible to perform control such that the lift speed of the valve body is rapidly increased to achieve a high fuel injection rate.
[0049]
In addition, the above function is realized only by a simple configuration in which the piston interferes with the fuel introduction port, or in addition, the fuel passage is provided in the piston, so that there is an advantage that it can be provided at low cost.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an apparatus according to the present invention. FIG. 2 is a diagram showing a fuel injection valve according to an embodiment. FIG. 3 is an enlarged sectional view showing another example of the fuel injection valve according to the embodiment. FIG. 5 is a timing chart showing the injection characteristics of the embodiment. FIG. 6 is a graph showing the application area of the control according to the present invention. FIG. Graph showing injection characteristics and desired injection characteristics 【Explanation of symbols】
1. Fuel tank 2 as fuel supply source. Fuel pump 3. Fuel accumulator chamber 4. Fuel supply path 5. Fuel injection valve 6. Fuel pressure sensor 7. Control device 8. Fuel pump drive Control unit 9 .. Fuel injection valve drive control unit 11 .. Relief valve 12 .. Fuel release path 21 .. Fuel injection hole 22 .. Cylindrical body 23 .. Needle valve 23 a .. Main piston 23 b. 23c, sub piston 24, coil spring 31, first fuel supply path 32, control chamber 33, second fuel supply path 33a, inlet orifice (fuel inlet)
34 .... Fuel discharge passage 34a..Outlet orifice 35..Back pressure control valve S1..Accelerator sensor S2..Intake pressure sensor S3..Water temperature sensor S4..Engine speed sensor S5..Aeroflow meter S6 .. G sensor

Claims (2)

A fuel injection valve that opens the fuel injection hole by pressing the valve body with the pressure of the high-pressure fuel introduced into the control chamber to close the fuel injection hole and discharging the high-pressure fuel inside the control chamber to lower the pressure of the valve body is provided. In the fuel injection device, the control chamber has a fuel introduction port for introducing high-pressure fuel, and the valve body has a piston that receives fuel pressure in the control chamber, and the piston introduces the fuel into the control chamber. A fuel injection device characterized in that the amount of fuel flowing into the control chamber is successively reduced by interfering with a port and sequentially reducing the passage cross-sectional area of the fuel introduction port as the piston rises. . A piston passage that interferes with the fuel introduction port has a fuel passage formed of a groove or a hole extending from the fuel introduction port to the control chamber, and a passage cross-sectional area between the fuel introduction port and the fuel passage is 2. The fuel injection device according to claim 1, wherein the fuel injection device decreases sequentially as the piston rises.

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