JP4337732B2 - Fuel injection method - Google Patents

Description

The present invention relates to a fuel injection how to inject and supply fuel to the engine.

[Conventional technology]
In recent years, the pressure (injection pressure) of fuel injected into an engine has become higher and higher in response to demands such as fuel efficiency reduction, higher output, and black smoke reduction in the engine. In response to such high injection pressure, for example, in a direct injection type engine such as a diesel engine, a common rail type fuel injection device capable of accumulating fuel in a high pressure state has been considered and put into practical use. Further, a fuel injection device that boosts the fuel accumulated in the common rail and supplies it to the injection nozzle is also considered.

  As described above, as a pressure increasing means for further increasing the pressure of the fuel to be injected, for example, a pressure increasing piston provided with a pressure receiving surface having a predetermined area and a pressure surface having an area smaller than the area of the pressure receiving surface is provided. What is used is known (for example, see Patent Document 1). According to this pressure increasing means, the pressure of the fuel is increased by causing the pressure of the fuel of the common rail to act on the pressure receiving surface and pressurizing the fuel with the pressing surface having a smaller area than the pressure receiving surface.

[Problems with conventional technology]
However, in the fuel injection device using this pressure increasing means, in addition to the existing fuel injection valve and the like, a storage chamber for storing a pressure increasing piston, a restoring spring, etc., a pressure chamber for receiving pressurized fuel, and a pressurized fuel It is necessary to provide a pressurized chamber for receiving the gas, a flow path for connecting each chamber to the common rail, the injection nozzle, and the like, and to arrange various valves and throttles. For this reason, the structure of the fuel injection device becomes extremely complicated.
Japanese Patent No. 2885076

The present invention has been made to solve the above problems, it is to provide a fuel injection method without taking the complicated structure Ru can pressure increase the injection pressure.

[Means of Claim 1]
The fuel injection device used in the fuel injection method according to claim 1 exerts pressure on the valve body that opens and closes the injection hole, and on the valve body in the opening direction that opens the injection hole from a predetermined fuel supply source. A fuel injection valve that has a high-pressure supply passage through which high-pressure fuel is supplied and an urging means that urges the valve body in the closing direction for closing the injection hole, and supplies the fuel to the engine. . The fuel injection device is mounted on the common rail and has a fuel supply pump having a fuel injection pump that discharges the fuel at a high pressure and a common rail that accumulates the fuel discharged from the fuel injection pump at a predetermined pressure. A two-way valve that closes or opens a high-pressure supply channel that leads high-pressure fuel from the source to the nozzle hole in response to a control command. Is temporarily provided downstream of its own valve body, thereby generating a pressure pulsation in the high pressure supply flow path, and a fuel cutoff valve for increasing the fuel in the high pressure supply flow path by the pressure pulsation.

As a result, it is possible to generate pressure pulsation by temporarily opening the fuel cutoff valve and temporarily guiding the fuel to the downstream side of the fuel cutoff valve. The pressure pulsation can increase the pressure of the fuel in the high-pressure supply channel on the downstream side of the fuel cutoff valve. For this reason, the injection pressure can be increased by a simple structure in which the fuel cutoff valve is incorporated in the high-pressure supply flow path.
Further, by mounting the fuel cutoff valve on the common rail, the flow path for generating pressure pulsation (that is, the flow path on the downstream side of the fuel cutoff valve: the high pressure supply flow path) can be lengthened. Thereby, the amount of pressure increase due to pressure pulsation can be increased.

Further, according to the method of the fuel injection this, after opening of the injection hole, again, temporarily opening the fuel cutoff valve, upstream of the fuel cutoff valve fuel of a high pressure supply passage which boosts the pressure pulsation , The fuel in the high-pressure supply flow path is depressurized.
As a result, the increased pressure of the fuel in the high-pressure supply channel can be recovered in the fuel supply source, and energy loss can be suppressed.

[Means of claim 2 ]
According to the fuel injection method of the second aspect , the pressure increase amount of the fuel in the high pressure supply flow path is changed by changing the length of the valve opening time for temporarily opening the fuel cutoff valve.
Thereby, an injection pressure can be adjusted.

[Means of claim 3 ]
According to the fuel injection method of the third aspect , the length of the interval period from when the fuel cutoff valve is temporarily opened to when the fuel cutoff valve is temporarily opened again is changed. Control the injection amount.
If the length of the interval period is changed, the length of time (injection period) during which the nozzle hole is opened can be changed. For this reason, the injection amount can be adjusted.

The fuel injection device used in the fuel injection method of the best mode 1 applies a pressure to the valve body that opens and closes the nozzle hole, and to the valve body in the opening direction that opens the nozzle hole from a predetermined fuel supply source. A fuel injection valve that includes a high-pressure supply passage through which high-pressure fuel is supplied and an urging unit that urges the valve body in a closing direction that closes the injection hole and supplies the fuel to the engine is provided. The fuel injection device is attached to the common rail, a fuel injection pump that discharges the fuel with a high pressure, a fuel supply source that has a common rail that accumulates fuel discharged from the fuel injection pump at a predetermined pressure, A two-way valve that closes or opens a high-pressure supply channel that leads high-pressure fuel from the supply source to the nozzle hole in accordance with a control command. A fuel cutoff valve is provided that induces a pressure pulsation in the high-pressure supply flow path by temporarily guiding the fuel to the downstream side of the valve body, and increases the fuel in the high-pressure supply flow path by the pressure pulsation.

The fuel injection method of the best mode 1, temporarily opening the fuel cutoff valve, by directing the downstream side of the temporary fuel cutoff valve fuel from a fuel supply source, the pressure pulsation in the high pressure supply passage And the pressure in the high pressure supply passage is increased by the pressure pulsation, thereby driving the valve body in the opening direction to open the nozzle hole.

Then , after the nozzle hole is opened, the fuel shut-off valve is temporarily opened again, and the fuel in the high-pressure feed passage increased by the pressure pulsation is led to the upstream side of the fuel shut-off valve. Depressurize the fuel .

Further, in this fuel injection method, the pressure increase amount of the fuel in the high pressure supply flow path is changed by changing the length of the valve opening time for temporarily opening the fuel cutoff valve. Further, the injection amount is controlled by changing the length of the interval period from the time when the fuel cutoff valve is temporarily opened to the time when the fuel cutoff valve is temporarily opened again.

[Configuration of Example 1]
The configuration of the fuel injection device 1 according to the first embodiment will be described with reference to FIGS. 1 to 3.
The fuel injection device 1 is a pressure accumulation type capable of accumulating high-pressure fuel. For example, the fuel injection device 1 injects and supplies fuel to a direct injection type engine (not shown: hereinafter referred to as an engine) such as a diesel engine. .

  As shown in FIG. 1, the fuel injection device 1 receives a supply of fuel from a predetermined fuel supply source, and supplies a fuel injection valve 2 that supplies the fuel to the engine, and supplies fuel from the fuel supply source to the fuel injection valve 2. A fuel shut-off valve 3 that shuts off the valve and opens the fuel supply source as necessary to enable the fuel supply from the fuel supply source to the fuel injection valve 2 is provided.

  Here, the predetermined fuel supply source is a fuel injection pump (not shown) that discharges the fuel in a fuel tank (not shown) at a high pressure, and accumulates the fuel discharged from the fuel injection pump at a predetermined pressure. The common rail 4 to be used. The operations of the fuel cutoff valve 3 and the fuel injection pump are electronically controlled by commands from an ECU (not shown).

  As shown in FIG. 1 or FIG. 2, the fuel injection valve 2 includes a valve body 7 that opens and closes the injection hole 6, and an urging unit that urges the valve body 7 in a direction in which the injection hole 6 is closed (closed hole direction). And a nozzle 9 for injecting fuel by opening and closing the nozzle hole 6 by the movement of the valve body 7. The nozzle 9 is fastened and connected to the lower side of the main body 12 of the fuel injection valve 2 by a retaining nut 11. The main body 12 is connected with a high-pressure pipe 15 for supplying fuel from the common rail 4 to the fuel injection valve 2 and a low-pressure pipe 16 opened to the atmosphere for reducing the internal pressure.

  The nozzle 9 is provided with a reservoir 19 that receives supply of fuel injected from the nozzle hole 6 and a spring 8 and a leak recovery chamber 20 that recovers fuel leaked from the reservoir 19 and the like. A seat surface 21 on which the valve body 7 is seated is provided below the pool portion 19, and the nozzle hole 6 is opened in the seat surface 21. In addition, the fuel in the pool portion 19 exerts pressure on the valve body 7 in the opening direction. That is, the pressure of fuel injected from the injection hole 6 (injection pressure) acts on the valve body 7 in the opening direction. Note that the leak recovery chamber 20 is closed at the bottom by the valve body 7, and its volume expands and contracts as the valve body 7 moves.

  When the injection pressure is increased, an urging force for urging the valve body 7 in the opening direction (referred to as an urging force for the opening: mainly an urging force by the injection pressure) causes the valve body 7 to move in the closing direction. It is stronger than the urging force to be urged (referred to as a closing hole urging force: mainly the urging force by the spring 8). Thereby, the valve body 7 is separated from the seat surface 21 and opens the nozzle hole 6. That is, when the injection pressure is increased, the opening urging force becomes stronger than the closing urging force, and the valve body 7 is driven in the opening direction by the injection pressure, and the injection hole 6 resists the urging force of the spring 8. Is released.

  Further, when the injection pressure is reduced, the opening urging force becomes weaker than the closing urging force. Thereby, the valve body 7 is seated on the seat surface 21 and closes the nozzle hole 6. That is, when the injection pressure is reduced, the opening urging force becomes weaker than the closing urging force, and the valve body 7 is urged in the closing direction by the spring 8 and moves in the closing direction, thereby closing the injection hole 6. To do.

  The injection pressure when the nozzle hole 6 is opened (referred to as the valve opening pressure P1) is higher than the injection pressure when the nozzle hole 6 is closed (referred to as the valve closing pressure P2) (FIG. 4 to FIG. 4). 7). That is, before the injection hole 6 is opened, the effective area of the working surface on which the injection pressure acts (valid opening effective pressure receiving area) is such that the valve body 7 is in contact with the seat surface 21 on the axial projection surface of the valve body 7. It is the area of the part of the outer peripheral side rather than the tangent (sheet part) which is. On the other hand, before the injection hole 6 is closed, the effective area of the working surface on which the injection pressure acts (the effective pressure receiving area when the valve is closed) is the entire area of the axial projection surface of the valve element 7. Thus, since the effective pressure receiving area at the time of valve opening is smaller than the effective pressure receiving area at the time of valve closing, the valve opening pressure P1 becomes higher than the valve closing pressure P2.

  The nozzle 9 and the main body 12 have a flow path a connecting the high pressure pipe 15 and the reservoir 19, a flow path b branched from the flow path a and connected to the low pressure pipe 16, an opening to the leak recovery chamber 20 and a flow path b. A flow path c connected to is provided.

  The flow path a and the high pressure pipe 15 form a high pressure supply flow path A for guiding fuel from the common rail 4 to the nozzle hole 6.

  The flow path b forms a high pressure discharge flow path B for discharging the fuel in the high pressure supply flow path A together with the low pressure pipe 16. The flow path b is provided with a throttle 23 as a discharge regulating means for regulating the discharge of fuel from the high pressure supply flow path A. The throttle 23 regulates the fuel discharge flow rate from the high pressure supply passage A. The flow path b incorporates a check valve 24 that opens when a pressure higher than atmospheric pressure is applied. The check valve 24 includes a valve member 25 that opens and closes the flow path b, and a spring 26 that biases the valve member 25 in a direction to close the flow path b.

  As will be described later, the valve opening pressure of the check valve 24 is preferably as low as possible in order to make the injection pressure higher by pressure pulsation. For this reason, the valve opening pressure of the check valve 24 is set to be slightly higher than the atmospheric pressure.

  The channel c forms a leak recovery channel together with the channel b and the low-pressure pipe 16 on the downstream side of the connection point with the channel b.

  As shown in FIG. 3, the fuel cutoff valve 3 is fastened and fixed by a retaining nut 29 and attached to the common rail 4. In response to a command from the ECU, the fuel shut-off valve 3 includes a solenoid 31 that receives power from a vehicle-mounted power source and generates a magnetic attractive force, a valve body 32 that is attracted and displaced by the magnetic attractive force, and the valve body 32 as a magnetic attractive force. It consists of a return spring 33 that urges in the opposite direction, a body 34, and the like. The body 34 is provided with flow passages 38a and 38b that open to the valve chambers 37a and 37b and the valve chambers 37a and 37b that are blocked or communicated by the displacement of the valve body 32, respectively.

  The common rail 4 has an upstream flow path 40 that opens to a pressure accumulation chamber 39 in which high-pressure fuel is accumulated and is connected to the flow path 38a, and a downstream flow path 41 that connects the high-pressure pipe 15 and the flow path 38b. Is provided. As described above, the fuel cutoff valve 3 is incorporated at the uppermost stream end of the high-pressure supply flow path A, closes the high-pressure supply flow path A, and opens the high-pressure supply flow path A in accordance with a command from the ECU.

  That is, when the solenoid 31 is energized, the valve body 32 is displaced to a position where the valve chamber 37a and the valve chamber 37b are communicated. Further, when energization to the solenoid 31 is stopped, the valve element 32 is displaced to a position where the valve chamber 37a and the valve chamber 37b are blocked.

  As a result, when the fuel shut-off valve 3 is activated (when the solenoid 31 is energized), the high-pressure supply passage A is opened to the common rail 4 and the fuel in the pressure accumulating chamber 39 is downstream from the fuel shut-off valve 3. To the high pressure supply channel A on the side. At this time, if the nozzle hole 6 is closed, the fuel pressure is reflected at the most downstream end of the high-pressure supply channel A (that is, the position where the valve element 7 is seated on the seat surface 21). For this reason, pressure pulsation occurs in the high pressure supply passage A, and the maximum value of the fuel pressure in the high pressure supply passage A becomes higher than the fuel pressure (common rail pressure PC) in the pressure accumulation chamber 39.

[Injection Method of Example 1]
The injection method of Example 1 is demonstrated using FIG.
First, as shown in FIG. 4A, in response to a command from the ECU, the fuel cutoff valve 3 is temporarily opened at a time T1 with a valve opening time of length T. As a result, the fuel accumulated in the common rail 4 is temporarily guided to the high-pressure supply channel A.

  As a result, as shown in FIG. 4B, the fuel pressure (corresponding to the injection pressure) in the high pressure supply passage A becomes higher than the common rail pressure PC due to pressure pulsation. Then, at time t2, when the injection pressure becomes higher than the valve opening pressure P1 of the fuel injection valve 2, as shown in FIGS. 4C and 4D, the injection hole 6 is opened and the injection supply to the engine starts. . While the injection is being performed, the injection pressure is maintained at a value corresponding to the length T of the valve opening time while oscillating in small increments.

  When the fuel pressure in the high pressure supply passage A increases, the check valve 24 in the high pressure discharge passage opens, and fuel discharge from the high pressure supply passage A to the high pressure discharge passage B begins. However, since the discharge flow rate is regulated by the throttle 23, the influence on the increase in the injection pressure is kept low.

  At time t3, the fuel cutoff valve 3 is temporarily opened again according to a command from the ECU. As a result, the fuel in the high-pressure supply flow path A that has been increased by the pressure pulsation is guided to the common rail 4. As a result, the injection pressure is reduced to a pressure lower than the valve closing pressure P2 of the fuel injection valve 2 at time t4. For this reason, the nozzle hole 6 is closed, and the injection supply to the engine ends. Note that the length of the interval period from the time when the fuel cutoff valve 3 is temporarily opened until the time when the fuel cutoff valve 3 is temporarily opened again is t3−t1.

  Even after the end of the injection (that is, after time t4), the throttle 23 regulates the discharge flow rate of the increased pressure, so that pressure pulsation remains in the high pressure supply channel A. However, the pressure pulsation is gradually attenuated, and the pressure of the fuel in the high pressure supply passage A is reduced to the valve opening pressure of the check valve 24 (which is substantially equal to the atmospheric pressure). As a result, the pressure of the fuel in the high-pressure supply flow path A is sufficiently reduced by the start of the next injection, and the injection pressure can be increased by pressure pulsation even in the next injection.

  Further, when it is desired to perform injection at a higher injection pressure, as shown in FIG. 5, for example, the fuel cutoff valve 3 is temporarily opened for a length T ′ of the valve opening time longer than the length T. To do. Thereby, the injection pressure during injection can be increased.

  Further, when it is desired to reduce the injection amount, as shown in FIGS. 6 and 7, for example, the length t3′-t1 of the interval period shorter than the length t3-t1 or the length t3 ″ -t1, Again, the fuel cutoff valve 3 is temporarily opened.

[Effect of Example 1]
The fuel injection device 1 according to the first embodiment includes a valve body 7 that opens and closes the injection hole 6 and a spring 8 that urges the valve body 7 in the closing direction, receives fuel supplied from the common rail 4, and injects the fuel into the engine. The fuel injection valve 2 to be supplied and the high-pressure supply flow path A for guiding the fuel from the common rail 4 to the nozzle hole 6 are closed, the high-pressure supply flow path A is closed, and the high-pressure supply flow path A is And a fuel cutoff valve 3 to be opened.
The fuel injected from the injection hole 6 is supplied to the valve body 7 so as to exert pressure in the opening direction. The valve body 7 is driven by the pressure of the fuel acting in the opening direction, and the spring 8 The nozzle hole 6 is opened against the urging force.

  As a result, the fuel cutoff valve 3 is temporarily opened, and pressure pulsation can be generated in the high-pressure supply channel A by temporarily guiding the fuel to the downstream side of the fuel cutoff valve 3. The pressure pulsation can increase the pressure of the fuel in the high pressure supply passage A. For this reason, it is possible to increase the injection pressure with a simple structure in which the fuel cutoff valve 3 is incorporated in the high-pressure supply flow path A, and to open the injection hole 6 by driving the valve body 7 in the opening direction. it can.

In the fuel injection device 1, a high-pressure discharge channel B for discharging the fuel in the high-pressure supply channel A branches from the high-pressure supply channel A.
When the pressure of the fuel is increased by pressure pulsation, the flow path through which the fuel is temporarily guided, that is, the flow path that generates pressure pulsation is preferably as low as possible. Therefore, as described above, if the high-pressure discharge flow path B is branched to discharge the fuel from the high-pressure supply flow path A that is a flow path that generates pressure pulsation, the high-pressure supply flow path A can be set to a low pressure. it can.

The high-pressure discharge passage B of the fuel injection device 1 is provided with a throttle 23 for regulating the fuel discharge flow rate.
As a result, when the high pressure supply passage A is used for the original purpose of “leading the fuel increased in pressure pulsation to the nozzle hole 6”, the influence of the fuel discharge from the high pressure discharge passage B can be reduced. it can.

A check valve 24 that opens when a pressure higher than atmospheric pressure is applied is incorporated in the high-pressure discharge passage B of the fuel injection device 1.
Thereby, the valve opening pressure of the check valve 24 can be selected from an arbitrary pressure value higher than the atmospheric pressure in accordance with the target value for increasing the injection pressure due to pressure pulsation. Here, the lower the pressure in the high-pressure supply channel A before the fuel is guided, the higher the injection pressure after pressure increase due to pressure pulsation. For this reason, the valve opening pressure of the check valve 24 is preferably as low as possible. According to the above configuration, for example, if the valve opening pressure of the check valve 24 is set to be slightly higher than the atmospheric pressure, the injection pressure after pressure increase due to pressure pulsation can be increased.

The fuel cutoff valve 3 of the fuel injection device 1 is attached to the common rail 4.
Thereby, the high-pressure supply flow path A on the downstream side of the fuel cutoff valve 3 that generates pressure pulsation can be lengthened. For this reason, the amount of pressure increase due to pressure pulsation can be increased. Moreover, the operation | work which equips the fuel injection apparatus 1 with the fuel cutoff valve 3 becomes easy, and the manufacturing man-hour of the fuel injection apparatus 1 can be reduced.

According to the fuel injection method of the first embodiment, the fuel cutoff valve 3 is temporarily opened, and the fuel is temporarily guided from the common rail 4 to the downstream side of the fuel cutoff valve 3, so that The pressure pulsation is generated and the fuel in the high pressure supply passage A is increased by the pressure pulsation, so that the valve body 7 is driven in the opening direction to open the injection hole 6.
Thus, the injection pressure can be increased and the increased injected fuel can be injected and supplied to the engine with a simple structure in which the fuel cutoff valve 3 is incorporated in the high-pressure supply passage A.

In addition, after the nozzle hole 6 is opened, the fuel shut-off valve 3 is temporarily opened again, and the fuel in the high-pressure supply passage A increased in pressure pulsation is led to the upstream side of the fuel shut-off valve 3. The nozzle 6 is closed by depressurizing the fuel in the high pressure supply passage A.
As a result, the fuel in the high-pressure supply channel A that has been increased in pressure can be recovered in the common rail 4 to suppress energy loss, and the injection pressure can be reduced to terminate the injection.

  Further, the amount of pressure increase of the fuel in the high pressure supply passage A can be changed by changing the length of the valve opening time during which the fuel cutoff valve 3 is temporarily opened. For this reason, the injection pressure can be adjusted.

  Further, the length of the injection period is changed by changing the length of the interval period from the time when the fuel cutoff valve 3 is temporarily opened to the time when the fuel cutoff valve 3 is temporarily opened again. be able to. For this reason, the injection amount can be adjusted.

[Modification]
The fuel cutoff valve 3 of the present embodiment is mounted on the common rail 4 corresponding to the most upstream portion of the high pressure supply flow path A, but may be incorporated in the high pressure pipe 15 or mounted on the fuel injection valve 2.
In this embodiment, the throttle 23 is provided as the discharge restricting means. However, the present invention is not limited to this mode. For example, the opening can be changed according to the discharge flow rate, the pressure of the discharged fuel, and the like. A mechanism may be provided as a discharge regulating means.

It is a block diagram of a fuel-injection apparatus (Example). It is a block diagram of a fuel injection valve (Example). It is a block diagram of a common rail and a fuel cutoff valve (Example). (A) is a time chart of the open / close state of the fuel cutoff valve, (b) is a time chart of the injection pressure, (c) is a time chart of the open / close state of the fuel injection valve, and (d) is the injection rate. (Example). (A) is a time chart of the open / close state of the fuel cutoff valve, (b) is a time chart of the injection pressure, (c) is a time chart of the open / close state of the fuel injection valve, and (d) is the injection rate. (Example). (A) is a time chart of the open / close state of the fuel cutoff valve, (b) is a time chart of the injection pressure, (c) is a time chart of the open / close state of the fuel injection valve, and (d) is the injection rate. (Example). (A) is a time chart of the open / close state of the fuel cutoff valve, (b) is a time chart of the injection pressure, (c) is a time chart of the open / close state of the fuel injection valve, and (d) is the injection rate. (Example).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection apparatus 2 Fuel injection valve 3 Fuel cutoff valve 4 Common rail (fuel supply source)
6 injection hole 7 valve body
A High pressure supply channel

Claims (3)

A valve body that opens and closes the nozzle hole, and a high-pressure supply passage through which high-pressure fuel is supplied so as to exert pressure on the valve body from a predetermined fuel supply source in the opening direction of opening the nozzle hole; A fuel injection device including a fuel injection valve that supplies fuel to an engine by urging means for urging the valve body in a closing direction for closing the injection hole;
A fuel injection pump that discharges the fuel at a high pressure, and the fuel supply source having a common rail that accumulates fuel discharged from the fuel injection pump at a predetermined pressure;
A two-way valve that is mounted on the common rail and that closes or opens the high-pressure supply passage that guides high-pressure fuel from the fuel supply source to the nozzle hole according to a control command, and temporarily closes its valve body. The valve is opened, and the fuel is temporarily guided from the fuel supply source to the downstream side of the valve body, thereby generating a pressure pulsation in the high pressure supply flow path, and the pressure pulsation causes the high pressure supply flow path. A fuel injection method using a fuel injection device comprising a fuel cutoff valve for increasing the pressure of the fuel ,
Temporarily opening the fuel shut-off valve, and temporarily guiding fuel from the fuel supply source to the downstream side of the fuel shut-off valve, thereby generating pressure pulsation in the high-pressure supply flow path;
By increasing the fuel in the high-pressure supply flow path by this pressure pulsation, the valve body is driven in the opening direction to open the nozzle hole,
After the injection hole is opened, the fuel shut-off valve is temporarily opened again, and the fuel in the high-pressure supply passage increased in pressure by the pressure pulsation is guided upstream of the fuel shut-off valve, A fuel injection method comprising depressurizing fuel in a high-pressure supply channel. A valve body that opens and closes the nozzle hole, and a high-pressure supply passage through which high-pressure fuel is supplied so as to exert pressure on the valve body from a predetermined fuel supply source in the opening direction of opening the nozzle hole; A fuel injection device including a fuel injection valve that supplies fuel to an engine by urging means for urging the valve body in a closing direction for closing the injection hole;
A fuel injection pump that discharges the fuel at a high pressure, and the fuel supply source having a common rail that accumulates fuel discharged from the fuel injection pump at a predetermined pressure;
A two-way valve that is mounted on the common rail and that closes or opens the high-pressure supply passage that guides high-pressure fuel from the fuel supply source to the nozzle hole according to a control command, and temporarily closes its valve body. The valve is opened, and the fuel is temporarily guided from the fuel supply source to the downstream side of the valve body, thereby generating a pressure pulsation in the high pressure supply flow path, and the pressure pulsation causes the high pressure supply flow path. A fuel injection method using a fuel injection device comprising a fuel cutoff valve for increasing the pressure of the fuel,
  Temporarily opening the fuel shut-off valve, and temporarily guiding fuel from the fuel supply source to the downstream side of the fuel shut-off valve, thereby generating pressure pulsation in the high-pressure supply flow path;
  By increasing the fuel in the high-pressure supply flow path by this pressure pulsation, the valve body is driven in the opening direction to open the nozzle hole,
A fuel injection method comprising: changing a pressure increase amount of fuel in the high-pressure supply flow path by changing a length of time during which the fuel cutoff valve is temporarily opened. A valve body that opens and closes the nozzle hole, and a high-pressure supply passage through which high-pressure fuel is supplied so as to exert pressure on the valve body from a predetermined fuel supply source in the opening direction of opening the nozzle hole; A fuel injection device including a fuel injection valve that supplies fuel to an engine by urging means for urging the valve body in a closing direction for closing the injection hole;
A fuel injection pump that discharges the fuel at a high pressure, and the fuel supply source having a common rail that accumulates fuel discharged from the fuel injection pump at a predetermined pressure;
A two-way valve that is mounted on the common rail and that closes or opens the high-pressure supply passage that guides high-pressure fuel from the fuel supply source to the nozzle hole according to a control command, and temporarily closes its valve body. The valve is opened, and the fuel is temporarily guided from the fuel supply source to the downstream side of the valve body, thereby generating a pressure pulsation in the high pressure supply flow path, and the pressure pulsation causes the high pressure supply flow path. A fuel injection method using a fuel injection device comprising a fuel cutoff valve for increasing the pressure of the fuel,
  Temporarily opening the fuel shut-off valve, and temporarily guiding fuel from the fuel supply source to the downstream side of the fuel shut-off valve, thereby generating pressure pulsation in the high-pressure supply flow path;
  By increasing the fuel in the high-pressure supply flow path by this pressure pulsation, the valve body is driven in the opening direction to open the nozzle hole,
After the injection hole is opened, the fuel shut-off valve is temporarily opened again, and the fuel in the high-pressure supply passage increased in pressure by the pressure pulsation is guided upstream of the fuel shut-off valve, Depressurize the fuel in the high-pressure supply channel,
The injection amount is controlled by changing the length of the interval period from the time when the fuel cutoff valve is temporarily opened to the time when the fuel cutoff valve is temporarily opened again. Fuel injection method.

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