JP2009235962A - Fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device in which two fuel injection valves are provided to each combustion chamber and a fuel injection amount from one of the fuel injection valves is controlled to be small, capable of preventing a reduction of the fuel injection amount from the one fuel injection valve. <P>SOLUTION: In the fuel injection device, the two fuel injection valves which are a first fuel injection valve 1 and a second fuel injection valve 2 are attached to each combustion chamber 52. The fuel injection device controls the fuel injection amount from a second injection hole of the second fuel injection valve 2 to be smaller as compared with the fuel injection amount from a first injection hole of the first fuel injection valve 1. In the fuel injection device, the diameter of the second injection hole is set larger than the diameter of the first injection hole. It is thus possible to prevent a reduction of the fuel injection amount, which is controlled to be small, from the second fuel injection valve 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel injection device in which two fuel injection valves are attached per combustion chamber.

  Conventionally, a fuel injection device in which two fuel injection valves, a first fuel injection valve and a second fuel injection valve, are mounted per combustion chamber has been put into practical use. As such a fuel injection device, an invention for reducing incomplete fuel combustion has been disclosed (see Patent Document 1).

  From the first injection hole of the first fuel injection valve, fuel is injected into the combustion chamber through the opened first intake valve, and from the second injection hole of the second fuel injection valve, through the opened second intake valve. The fuel is injected into the same combustion chamber. In such a fuel injection device, the first intake valve is opened while the second intake valve is closed, or the lift amount of the second intake valve is controlled to be smaller than the lift amount of the first intake valve. There is something.

In the control to open the first intake valve while closing the second intake valve, the fuel injection from the second fuel injection valve is stopped while performing the fuel injection from the first fuel injection valve. In the control for reducing the lift amount of the second intake valve as compared with the lift amount of the first intake valve, the fuel injection amount from the second fuel injection valve is compared with the fuel injection amount from the first fuel injection valve. Make it smaller. The fuel injection amount from the second fuel injection valve by the control for closing the second intake valve or the control for reducing the lift amount of the second intake valve, that is, compared with the fuel injection amount from the first fuel injection valve The vehicle is driven at a low speed by the control for reducing.
JP 2007-292058 A

  In the first injection hole of the first fuel injection valve and the second injection hole of the second fuel injection valve, residual fuel remaining around the injection hole after fuel injection is deposited as a deposit (carbon-based compound) around the injection hole. To occur. When this deposit penetrates into the nozzle hole, the deposit grows on the inner peripheral surface of the nozzle hole, and the film thickness of the deposit increases on the inner peripheral surface of the nozzle hole. When the deposit film thickness is increased on the inner peripheral surface of the nozzle hole, the nozzle hole area is reduced, but the deposit is washed away by fuel injection from the nozzle hole, so that the reduction of the nozzle hole area is suppressed.

  However, in the second injection hole of the second fuel injection valve in which the fuel injection amount is controlled to be smaller than the fuel injection amount from the first fuel injection valve, the fuel from the injection hole is compared with the first injection hole. Since the effect of washing away deposits by jetting is low, the thickness of the deposit is increased on the inner peripheral surface of the nozzle hole. For this reason, in the 2nd fuel injection valve compared with the 1st fuel injection valve, the nozzle hole area falls and the problem that the fall of fuel injection quantity becomes large has arisen.

  The present invention has been made in view of such circumstances, and in a fuel injection device in which two fuel injection valves are attached per combustion chamber and the fuel injection amount from one is controlled to be small, It aims at suppressing the fall of the fuel injection amount from one side.

  In order to achieve the above object, the present invention employs the following technical means.

  The fuel injection device according to claim 1 is provided with two fuel injection valves, a first fuel injection valve and a second fuel injection valve, per one combustion chamber, from the first injection hole of the first fuel injection valve. In the fuel injection device for controlling the fuel injection amount from the second injection hole of the second fuel injection valve to be smaller than the fuel injection amount of the second injection hole, the second injection hole is compared with the first injection hole diameter of the first injection hole. The second nozzle hole diameter is set large.

  According to the first aspect of the present invention, the fuel injection amount from the second injection hole of the second fuel injection valve is controlled to be smaller than the fuel injection amount from the first injection hole of the first fuel injection valve. In the second nozzle hole, compared with the first nozzle hole, the effect of washing out the deposit by the fuel injection from the nozzle hole is low. For this reason, in the 2nd nozzle hole, compared with the 1st nozzle hole, the film thickness of the deposit becomes thick on the inner peripheral surface of the nozzle hole.

  On the other hand, since the second nozzle hole diameter of the second nozzle hole is set larger than the first nozzle hole diameter of the first nozzle hole, the film thickness of the deposit is increased on the inner peripheral surface of the nozzle hole. In addition, the rate of decrease in the nozzle hole area can be suppressed in the second fuel injection valve. Therefore, it is possible to suppress a decrease in the fuel injection amount from the second fuel injection valve whose fuel injection amount is controlled to be small.

  According to the second aspect of the present invention, since the fuel injection from the first injection hole is stopped while the fuel injection from the second injection hole is stopped, the injection of the second injection hole is smaller than that of the first injection hole. The film thickness of the deposit increases on the inner peripheral surface of the hole. On the other hand, since the 2nd nozzle hole diameter is set large compared with the 1st nozzle hole diameter, there can exist the same effect.

  According to the invention described in claim 3, since the number of second nozzle holes of the second nozzle holes is set smaller than the number of first nozzle holes of the first nozzle holes, the second nozzle hole diameter is increased. An increase in the total area of the second nozzle holes due to the setting can be suppressed. Therefore, the combination of setting the second nozzle hole diameter large and setting the second nozzle hole number small can provide the same effect, and the total area of the second nozzle hole is set to a predetermined value. It becomes possible to set to.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the mutually same or equivalent part in a figure.

(First embodiment)
A fuel injection device 100 shown in FIG. 1 is a fuel injection device in which two fuel injection valves are attached per combustion chamber in a multi-cylinder engine 5. The engine 5 includes a plurality of cylinders, and a combustion chamber is provided in each cylinder. The cylinder head of the cylinder 51 is provided with two intake ports 531, 532, intake valves 541, 542, an exhaust port 55, an exhaust valve 56, and a spark plug 57. A first fuel injection valve 1 for injecting fuel into the combustion chamber 52 from the opened first intake valve 541 is attached to the first intake port 531, and the opened second intake air is connected to the second intake port 532. A second fuel injection valve 2 that injects fuel from the valve 542 into the combustion chamber 52 is attached.

  Since the same applies to the other combustion chambers, two fuel injection valves 1 and 2 attached to the combustion chamber 52 will be described as an example.

  The fuel injection device 100 includes fuel injection valves 1 and 2, a delivery pipe 3, and a control device (ECU) 4. The delivery pipe 3 is a distribution pipe that supplies high-pressure fuel to the fuel injection valves 1 and 2, and the control device 4 controls the fuel injection from the fuel injection valves 1 and 2 by supplying power to the fuel injection valves 1 and 2. It is a control device. The fuel injection from the fuel injection valves 1 and 2 is configured to be controlled independently by the control device 4.

  The fuel injection amount from the second fuel injection valve 2 is controlled to be smaller than the fuel injection amount from the first fuel injection valve 1. In this control, as shown in FIG. 2, the lift amount L2 of the second intake valve 542 is controlled to be smaller than the lift amount L1 of the first intake valve 541. By controlling in this way, the power of the engine 5 is kept low and the vehicle travels at a low speed.

  On the other hand, when the vehicle travels at a high speed or climbs a steep slope, high power is required for the engine 5. In this case, the lift amount L2 of the second intake valve 542 is increased so as to approach the lift amount L1 of the first intake valve 541, and the fuel injection amount from the second fuel injection valve 2 is increased from the first fuel injection valve 1. Increase the fuel injection amount so that it approaches. Thus, the 2nd fuel injection valve 2 is a sub fuel injection valve which assists the 1st fuel injection valve 1, and it can be said that the 1st fuel injection valve 1 is a main fuel injection valve. In FIG. 2, the spark plug 57 shown in FIG. 1 is omitted for easy understanding of the drawing.

  Since the fuel injection valves 1 and 2 have the same configuration, the first fuel injection valve 1 will be described as an example.

  3 and 4, the fuel injection valve 1 is a needle 13 that opens and closes a nozzle hole 122 through which fuel is injected, and a needle that is excited when the coil 161 is energized to open the nozzle hole 122 (upward in FIG. 3). 13 is provided with a fixed core 15 that sucks 13 and a spring 17 that biases the needle 13 in the direction of closing the nozzle hole 122 (downward in FIG. 3).

  The cylindrical member 14 has a fuel passage 14A formed therein, and the fuel passage 14A accommodates a needle 13, a movable core 133 fixed to the needle 13, a valve body 12, a fixed core 15, a spring 17 and an adjusting pipe 171. Is done. The cylinder member 14 includes a first magnetic cylinder part 141, a non-magnetic cylinder part 142, and a second magnetic cylinder part 143, which are joined and integrated by, for example, laser welding. The valve body 12 is fixed to the first magnetic cylinder portion 141 by welding.

  The valve body 12 is fixed with a nozzle plate 121 formed in a thin plate shape and a cup shape in FIG. A plurality of injection holes 122 are formed in the injection hole plate 121. In FIG. 4, a single nozzle hole 122 is shown to make the drawing easy to see. A plate holder 123 that covers the nozzle hole plate 121 is attached to the outside of the nozzle hole plate 121. The valve body 12 is formed in a cylindrical shape, and has a valve seat 120 on the inner peripheral surface in FIG. The nozzle hole 122 is disposed on the fuel flow outlet side of the valve seat 120.

  In FIG. 3, the needle 13 is formed in a bottomed cylindrical shape having a fuel passage 13 </ b> A therein, and is press-fitted and fixed to the movable core 133. A seat portion 131 that can be seated on the valve seat 120 formed on the inner peripheral surface of the valve body 12 in FIG. 4 is formed at the end of the needle 13 opposite to the movable core 133. The needle 13 forms a fuel passage 12 </ b> A with the inner peripheral surface of the valve body 12. When the seat portion 131 is seated on the valve seat 120, the communication between the fuel passage 12 </ b> A and the injection hole 122 is blocked, and fuel is not injected from the injection hole 122.

  The needle 13 has a fuel hole 132 penetrating the side wall, and the fuel that has flowed into the inner peripheral side of the needle 13 flows out to the outer peripheral side of the needle 13 through the fuel hole 132 and flows to the fuel passage 12A. The valve body 12 has a guide portion 12B on the inner peripheral side, and the needle 13 slides with the guide portion 12B of the valve body 12, and the movement in the axial direction is guided by the guide portion 12B.

  In FIG. 3, the fixed core 15 is formed in a cylindrical shape, and is fixed to the cylindrical member 14 by being press-fitted into the nonmagnetic cylindrical portion 142 and the second magnetic cylindrical portion 143.

  The adjusting pipe 171 is press-fitted inside the fixed core 15. One end of the spring 17 abuts on the adjusting pipe 171 and the other end abuts on the movable core 133. The spring 17 biases the seat portion 131 of the needle 13 in the direction in which the seat portion 131 of the needle 13 is seated on the valve seat 120 of the valve body 12. The set load of the spring 17 is changed by adjusting the press-fitting amount of the adjusting pipe 171.

  A valve housing 11 made of a magnetic member is disposed on the outer periphery of the cylindrical member 14 with a coil 161 that is energized to generate electromagnetic force in FIG. The valve body 12 side portion of the valve housing 11 is press-fitted into the outer peripheral side of the first magnetic cylinder portion 141. A portion of the valve housing 11 on the side opposite to the valve body 12 surrounds the outer peripheral side of the coil 161. A housing plate 110 made of a magnetic member is disposed on the outer periphery of the cylindrical member 14 with the coil 161 interposed therebetween. The valve housing 11 and the housing plate 110 are magnetically connected to each other and installed on the outer peripheral side of the coil 161. The fixed core 15, the movable core 133, the first magnetic cylinder part 141, the valve housing 11, the housing plate 110, and the second magnetic cylinder part 143 constitute a magnetic circuit.

  A coil 161 for operating the above-described magnetic circuit is attached to the outer periphery of the cylindrical portion 14. The coil 161 is electrically connected to the terminal 162, and the terminal 162 is connected to the control device 4. As a result, the drive current i <b> 1 is supplied from the control device 4 to the coil 161 via the terminal 162.

  The resin housing 16 is a resin housing formed by assembling the needle 13, the movable core 133, the fixed core 15, the valve housing 11, the spring 17, the coil 161, and the like and then molding the resin material. The terminal 162 is also insert-molded at the same time.

  The fuel supplied to the first fuel injection valve 1 from the delivery pipe 3 in which the fuel is accumulated is removed from the upper portion in FIG. 3 of the cylindrical portion 14 by the filter 18 and flows into the fuel passage 14A. This fuel passes through the inner peripheral side of the adjusting pipe 171, the inner peripheral side of the fixed core 15, the inner peripheral side of the movable core 133, the fuel passage 13 </ b> A of the needle 13, and the fuel hole 12 </ b> A shown in FIG. 4. Supplied to. That is, in the first fuel injection valve 1, the fuel passage 12A is always filled with fuel pressurized to a predetermined pressure.

  When no drive current is supplied from the control device 4 to the coil 161, no magnetic attractive force is generated between the fixed core 15 and the movable core 133, so that the movable core 133 is fixed by the urging force of the spring 17. It moves to the direction which leaves | separates from, ie, the valve body 12, direction. As a result, the seat 131 of the needle 13 integral with the movable core 133 is seated on the valve seat 120 of the valve body 12, and the fuel passage 12 </ b> A is not in communication with the injection hole 122. Accordingly, fuel is not injected from the nozzle hole 122.

  When the drive current i1 is supplied from the control device 4 to the coil 161, the magnetic material composed of the fixed core 15, the movable core 133, the first magnetic cylinder part 141, the valve housing 11, the housing plate 110, and the second magnetic cylinder part 143 is provided. The coil 161 generates a magnetic flux that passes through the circuit. As a result, a magnetic attractive force is generated between the excited fixed core 15 and the movable core 133, and when this magnetic attractive force becomes larger than the biasing force of the spring 17, the movable core 133 moves in the direction of the fixed core 15. To do. The movable core 133 moves until it collides with the fixed core 15. Therefore, the needle 13 integrated with the movable core 133 also moves upward in FIG. As a result, the seat portion 131 of the needle 13 is separated from the valve seat 120 of the valve body 12. As a result, the above-described fuel passage 12A communicates with the injection hole 122, so that fuel flows from the fuel passage 12A to the injection hole 122 and fuel is injected from the injection hole 122. By changing the pulse width t1 of the drive current i1, the injection pulse width from the nozzle hole 122, that is, the fuel injection amount can be changed.

  On the other hand, a drive current i2 having a pulse width t2 is supplied from the control device 4 to the second fuel injection valve 2 separately from the drive current i1, whereby the fuel injection of the second fuel injection valve 2 is controlled by the control device. 4 is controlled independently of the fuel injection of the first fuel injection valve 1. These controls are performed so that the fuel injection amount from the injection hole 222 (FIG. 5) of the second fuel injection valve 2 is made smaller than the fuel injection amount from the injection hole 122 of the first fuel injection valve 1. .

  In such a configuration, the nozzle hole diameter D2 of the nozzle hole 222 of the second fuel injection valve 2 is set larger than the nozzle hole diameter D1 of the nozzle hole 122 of the first fuel injection valve 1 (FIG. 5). Compared with the number of injection holes N1 of the injection holes 122 of the fuel injection valve 1, the number of injection holes N2 of the injection holes 222 of the second fuel injection valve 2 is set to be small. For example, the nozzle hole diameter D1 is 0.12 mm, the nozzle hole diameter D2 is 0.25 mm, the nozzle hole number N1 is 18, and the nozzle hole number N2 is 4. In this example, the nozzle hole area A1 that is the total area of the eighteen nozzle holes 122 and the nozzle hole area A2 that is the total area of the four nozzle holes 222 are equal.

  When the nozzle hole area A1 and the nozzle hole area A2 are equal, the second fuel injection is compared with the fuel injection amount from the nozzle hole 122 of the first fuel injection valve 1 by setting the pulse width t2 shorter than the pulse width t1. The fuel injection amount from the nozzle hole 222 of the valve 2 can be reduced. In FIG. 5, the nozzle holes 122 and 222 are shown to be overlapped for simplification of the drawing.

  The nozzle hole 122 corresponds to the first nozzle hole described in the claims, the nozzle hole diameter D1 corresponds to the first nozzle hole diameter described in the claims, and the number N1 of the nozzle holes corresponds to the first nozzle hole described in the claims. Corresponds to the number of holes. The nozzle hole 222 corresponds to the second nozzle hole recited in the claims, the nozzle hole diameter D2 corresponds to the second nozzle hole diameter recited in the claims, and the number of nozzle holes N2 represents the second nozzle hole recited in the claims. Corresponds to the number of holes.

  With the above configuration, the second fuel injection valve is controlled in order to control the fuel injection amount from the injection hole 222 of the second fuel injection valve 2 smaller than the fuel injection amount from the injection hole 122 of the first fuel injection valve 1. In the second nozzle hole 222, compared with the nozzle hole 122 of the first fuel injection valve 1, the effect of flushing the deposit by the fuel injection from the nozzle hole 222 is low. Therefore, in FIG. 5, it occurs on the inner peripheral surface of the injection hole 222 of the second fuel injection valve 2 as compared with the film thickness T1 of the deposit DP generated on the inner peripheral surface of the injection hole 122 of the first fuel injection valve 1. The film thickness T2 of the deposit DP is increased.

  On the other hand, since the nozzle hole diameter D2 of the nozzle hole 222 of the second fuel injection valve 2 is set larger than the nozzle hole diameter D1 of the nozzle hole 122 of the first fuel injection valve 1, the inner periphery of the nozzle hole Even if the film thickness of the deposit DP becomes thick on the surface, the rate of decrease of the injection hole area A2 in the second fuel injection valve 2 can be suppressed. This will be described with reference to FIG.

  The horizontal axis in FIG. 6 represents the nozzle hole diameter ratio D2 / D1 with the nozzle hole diameter D1 being 0.12 mm. Therefore, in the above example, the nozzle hole diameter D1 is set to 0.12 mm, and the nozzle hole diameter D2 is set to 0.25 mm. Therefore, the nozzle hole diameter ratio D2 / D1 is approximately 2.1.

  The vertical axis | shaft of FIG. 6 shows the calculated value of the decreasing rate (-(DELTA) A2 / A2 (%)) of nozzle hole area A2. The nozzle hole area A2 represents the nozzle hole area before deposit DP is generated on the inner peripheral surface of the nozzle hole 222 in FIG. 5, that is, the nozzle hole area when the nozzle hole diameter is D2. ΔA2 represents an area reduced due to the occurrence of the deposit DP of the film thickness T2. The rate of decrease in the nozzle hole area A2 in the second fuel injection valve 2 is (−ΔA2 / A2), and “−” indicates that the rate of decrease in the nozzle hole area A2 (−ΔA2 / A2) This is because it is shown on the positive side of the vertical axis in FIG. Therefore, in the vertical axis of FIG. 6, the upper side shows that the rate of decrease of the nozzle hole area A2 (−ΔA2 / A2) is large, and the lower side shows the rate of decrease of the nozzle hole area A2 (−ΔA2 / A2). Indicates small. In FIG. 6, the reduction rate (−ΔA2 / A2 (%)) of the nozzle hole area A2 is calculated by setting the film thickness T2 to 5 μm.

  As is clear from FIG. 6, as the nozzle hole diameter ratio D2 / D1 is increased, that is, as the nozzle hole diameter D2 is set larger than the nozzle hole diameter D1, the nozzle hole area A2 decreases in the second fuel injection valve 2. The rate (−ΔA2 / A2) is small. In other words, by setting the nozzle hole diameter D2 to be larger than the nozzle hole diameter D1, the nozzle hole area A2 in the second fuel injection valve 2 even if the film thickness T2 of the deposit DP is increased on the inner peripheral surface of the nozzle hole 222. It is possible to suppress the decrease rate of. Accordingly, it is possible to suppress a decrease in the fuel injection amount from the second fuel injection valve 2 whose fuel injection amount is controlled to be small.

  In addition, since the number of injection holes N2 of the injection holes 222 of the second fuel injection valve 2 is set smaller than the number of injection holes N1 of the injection holes 122 of the first fuel injection valve 1, the second fuel injection valve An increase in the nozzle hole area A2 which is the total area of the second nozzle holes 222 due to the nozzle hole diameter D2 of the second nozzle hole 222 being set large can be suppressed. Therefore, by combining the setting of the nozzle hole diameter D2 larger and the setting of the nozzle hole number N2 smaller, it is possible to obtain the effect of suppressing the decrease in the fuel injection amount from the second fuel injection valve 2, and the injection The hole area A2 can be set to a predetermined value. This will be described with reference to FIG. 7, taking as an example the case where the nozzle hole area A2 is set to the nozzle hole area A1.

  In FIG. 7, in the case where the nozzle hole area A2 of the second fuel injection valve 2 is equal to the nozzle hole area A1 of the first fuel injection valve 1 and the film thickness T2 of the deposit DP is 5 μm, the horizontal axis is The nozzle hole number ratio is N2 / N1, and the vertical axis is the calculated value of the rate of decrease of the nozzle hole area A2 (−ΔA2 / A2 (%)). Therefore, in the above-described example, the number of nozzle holes N1 is 18 and the number of nozzle holes N2 is 4. Therefore, in FIG. 7, the nozzle hole ratio N2 / N1 is approximately 0.22.

  As is apparent from FIG. 7, when the nozzle hole area A2 is equal to the nozzle hole area A1, the nozzle hole number N2 is reduced as the nozzle hole ratio N2 / N1 is reduced, that is, compared with the nozzle hole number N1. As the setting is made, the rate of decrease (−ΔA2 / A2) of the nozzle hole area A2 in the second fuel injection valve 2 becomes smaller. That is, in the case where the nozzle hole area A2 is equal to the nozzle hole area A1, the nozzle hole diameter D2 is set larger than the nozzle hole diameter D1 in order to set the nozzle hole number N2 smaller than the nozzle hole number N1. As a result, the rate of decrease of the nozzle hole area A2 (−ΔA2 / A2) is reduced. In other words, by setting the nozzle hole diameter D2 to be larger than the nozzle hole diameter D1, the rate of decrease in the nozzle hole area A2 (−ΔA2 / A2) is reduced, and the nozzle hole number N2 is set to be smaller than the nozzle hole number N1. By setting the number small, it can be said that the nozzle hole area A2 is set to the nozzle hole area A1 while suppressing an increase in the nozzle hole area A2.

  Therefore, if the nozzle hole diameter D2 is set to be large and the nozzle hole number N2 is set to be small, the nozzle hole area A2 can be set to a predetermined value, and the rate of decrease of the nozzle hole area A2 (−ΔA2). / A2) can be reduced. That is, the nozzle hole area A2 can be set to a predetermined value, and a decrease in the fuel injection amount from the second fuel injection valve 2 can be suppressed.

  When the nozzle hole area A1 and the nozzle hole area A2 are different, the pulse width t1 and the pulse are set so that the fuel injection amount from the second fuel injection valve 2 is smaller than the fuel injection amount from the first fuel injection valve 1. A width t2 is set.

  As described above, the second fuel injection valve 2 is a sub fuel injection valve that assists the first fuel injection valve 1, and the first fuel injection valve 1 can be said to be a main fuel injection valve. Therefore, in the main first fuel injection valve 1, priority is given to atomization of the fuel injection, the injection hole diameter D1 is made smaller than the injection hole diameter D2, and in the sub second fuel injection valve 2, the fuel injection amount is reduced. The injection hole diameter D2 is made larger than the injection hole diameter D1 with priority given to suppressing the decrease. Therefore, the main first fuel injection valve 1 can maintain the atomization of the fuel injection, and the sub second fuel injection valve 2 can suppress a decrease in the fuel injection amount.

(Second Embodiment)
In the second embodiment, in the fuel injection device 101 shown in FIG. 8, fuel injection from the first fuel injection valve 1 (injection hole 122) is stopped while fuel injection from the second fuel injection valve 2 (injection hole 222) is stopped. Let In this control, as shown in FIG. 9, the first intake valve 541 is opened while the second intake valve 542 is closed. By controlling in this way, the power of the engine 5 is kept low and the vehicle travels at a low speed.

  On the other hand, when the vehicle travels at a high speed or climbs a steep slope, high power is required for the engine 5. In this case, in addition to the first intake valve 541, the second intake valve 542 is also opened, and fuel is injected from both the fuel injection valves 1 and 2. Also in the second embodiment, the second fuel injection valve 2 can be said to be a sub fuel injection valve that assists the first fuel injection valve 1. In FIG. 9, the spark plug 57 shown in FIG. 8 is omitted for easy understanding of the drawing.

  As described above, the fuel injection control is always performed on the first fuel injection valve 1, whereas the fuel injection control is stopped when the second fuel injection valve 2 travels at a low speed. Then, it can be said that the fuel injection amount from the second fuel injection valve 2 is controlled to be smaller than the fuel injection amount from the first fuel injection valve 1. For this reason, in the injection hole 222 of the 2nd fuel injection valve 2, compared with the injection hole 122 of the 1st fuel injection valve 1, the effect which flushes the deposit DP by the fuel injection from the injection hole 222 is low. Therefore, in FIG. 5, the deposit generated on the inner peripheral surface of the injection hole 222 of the second fuel injection valve 2 as compared with the film thickness T1 of the deposit DP generated on the inner peripheral surface of the injection hole 122 of the first fuel injection valve 1. The film thickness T2 of DP increases.

  On the other hand, also in this embodiment, by setting the nozzle hole diameter D2 of the nozzle hole 222 of the second fuel injection valve 2 larger than the nozzle hole diameter D1 of the nozzle hole 122 of the first fuel injection valve 1, Even if the film thickness of the deposit DP increases on the inner peripheral surface of the nozzle hole, the rate of decrease of the nozzle hole area A2 can be suppressed in the second fuel injection valve 2. Accordingly, it is possible to suppress a decrease in the fuel injection amount from the second fuel injection valve 2 whose fuel injection amount is controlled to be small.

It is a mimetic diagram showing a fuel injection device by a 1st embodiment of the present invention. It is sectional drawing of the II-II line | wire in FIG. It is a longitudinal cross-sectional view of the 1st fuel injection valve shown in FIG. It is an expanded sectional view of the IV section in FIG. It is explanatory drawing of the deposit produced in a nozzle hole. It is a 1st graph explaining the effect of this invention. It is a 2nd graph explaining the effect of this invention. It is a schematic diagram which shows the fuel-injection apparatus by 2nd Embodiment of this invention. It is sectional drawing of the IX-IX line in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100,101 Fuel injection apparatus, 1 1st fuel injection valve, 110 Housing plate 11 Valve housing, 12 Valve body, 12A Fuel passage, 12B Guide part 120 Valve seat, 121 Injection hole plate, 122 Injection hole (1st injection hole)
123 plate holder, 13 needle, 13A fuel passage, 131 seat portion 132 fuel hole, 133 movable core, 14 cylinder member, 14A fuel passage 141 first magnetic cylinder portion, 142 non-magnetic cylinder portion, 143 second magnetic cylinder portion, 15 Fixed core 16 Resin housing, 161 coil, 162 terminal, 17 spring 171 adjusting pipe, 18 filter, D1 nozzle hole diameter (first nozzle hole diameter)
N1 number of injection holes (first number of injection holes), 2nd fuel injection valve, 222 injection holes (second injection hole)
D2 injection hole diameter (second injection hole diameter), N2 injection hole number (second injection hole number), 3 delivery pipe 4 control unit (ECU), 5 engine, 51 cylinder, 52 combustion chamber 531 first intake port, 532 second Intake port, 541 First intake valve 542 Second intake valve, 55 Exhaust port, 56 Exhaust valve, 57 Spark plug DP deposit

Claims (3)

Two fuel injection valves, a first fuel injection valve and a second fuel injection valve, are attached per combustion chamber, and compared with the fuel injection amount from the first injection hole of the first fuel injection valve. In the fuel injection device that controls the fuel injection amount from the second injection hole of the two fuel injection valve small,
The fuel injection device, wherein the second injection hole diameter of the second injection hole is set larger than the first injection hole diameter of the first injection hole.   2. The fuel injection device according to claim 1, wherein fuel injection is performed from the first nozzle hole while fuel injection from the second nozzle hole is stopped. 3.   3. The fuel injection device according to claim 1, wherein the second injection hole number of the second injection hole is set to be smaller than the first injection hole number of the first injection hole.

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