JP2007132215A - Fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To actualize early fuel pressure rise at starting an engine and prevent an increase of fuel pressure pulsation up to a lower limit value for fuel pressure during normal operation even in fuel pressure drop. <P>SOLUTION: This fuel injection device comprises a first delivery pipe 21A to which fuel is supplied from a high pressure pump 30, a second delivery pipe 21B communicated with the first delivery pipe 21A, and a capacity selector valve 22 having a valve element 22b which is operated to cut off the first and second delivery pipes 21A, 22A from each other when they have fuel pressure lower than first predetermined pressure. It also has a valve element operating means 23 for opening the capacity selector valve 22 to communicate the first delivery pipe 21A with the second delivery pipe 21B when the first delivery pipe 21A has fuel pressure not lower than second predetermined pressure higher than the first predetermined pressure and for holding the capacity selector valve 22 in an opened condition until the first and second delivery pipes 21A, 21B has fuel pressure lower than the first predetermined pressure, and a fuel injection valve 10 to which fuel is supplied from the first delivery pipe 21A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel injection device that injects a predetermined amount of fuel at a high pressure.

  2. Description of the Related Art Conventionally, there is a fuel injection device that includes two delivery pipes and communicates or blocks the two delivery pipes using an on-off valve that is controlled to open and close with a predetermined fuel pressure. For example, this type of fuel injection device is disclosed in the following Patent Documents 1 to 3. In the fuel injection devices disclosed in Patent Documents 1 to 3, the on-off valve is controlled to be closed so that fuel is supplied only to one delivery pipe when the engine is started, so as to increase the fuel pressure early. During normal operation, the on-off valve is controlled to open at a predetermined fuel pressure or higher so that fuel is supplied to the two delivery pipes, thereby reducing fuel pressure pulsation. In Patent Document 3, a throttle portion is provided in a connecting pipe that connects two delivery pipes.

  Patent Document 4 below discloses a fuel injection device that is provided with a variable displacement device that adjusts the volume of fuel supplied to a single delivery pipe, and that reduces the volume of the fuel when the engine is started.

JP-A-8-170571 JP-A-11-62773 JP 2005-127297 A JP 2002-310037 A

  However, in the fuel injection devices of Patent Documents 1 to 3 described above, when the fuel pressure of the two delivery pipes is lower than the predetermined fuel pressure during normal driving, the fuel pressure reaches the lower limit during normal driving. In spite of this, the on-off valve closes and fuel is supplied to only one delivery pipe, so the fuel pressure pulsation increases.

  Therefore, the present invention improves the inconvenience of such a conventional example, increases the fuel pressure early when starting the engine, and increases the fuel pressure pulsation to the lower limit value of the fuel pressure even if the fuel pressure decreases during normal operation. It is an object to provide a non-fuel injection device.

  In order to achieve the above object, according to the first aspect of the present invention, a first delivery pipe supplied with fuel pumped from a high pressure pump, a second delivery pipe communicating with the first delivery pipe, and the first delivery pipe are provided. A volume switching valve provided with a valve element that operates to shut off between the pipe and the second delivery pipe when the pressure is lower than the first predetermined pressure; and a second that the first delivery pipe is higher than the first predetermined pressure. When the pressure exceeds a predetermined pressure, the volume switching valve is opened to allow communication between the first delivery pipe and the second delivery pipe, and the first and second delivery pipes become lower than the first predetermined pressure. Up to this point, there are provided valve body operating means for holding the open state of the volume switching valve and a fuel injection valve to which fuel is supplied from the first delivery pipe.

  According to the fuel injection device of the first aspect, fuel is injected only from the first delivery pipe until the first delivery pipe becomes equal to or higher than the second predetermined pressure, and the first delivery pipe becomes equal to or higher than the second predetermined pressure. When this happens, the fuel can be injected using the total volume of the first and second delivery pipes with large volumes until the pressure drops to a first predetermined pressure lower than the second predetermined pressure.

  For example, as the valve body operating means, as in the invention described in claim 2, the communication path for communicating the first delivery pipe and the valve chamber of the volume switching valve, and the first delivery pipe is at a second predetermined pressure or higher. It is possible to use an open / close valve that communicates the first delivery pipe with the communication path when the first delivery pipe is extended, and that extends to communicate with the second delivery pipe.

  In the fuel injection device according to claim 2, when the first delivery pipe becomes equal to or higher than the second predetermined pressure, the fuel in the first delivery pipe is supplied to the valve chamber to open the volume switching valve. Can do. Even if the first delivery pipe is lower than the second predetermined pressure and the on-off valve is closed, the second delivery pipe and the valve chamber communicate with each other through the communication path. Until the second delivery pipe becomes lower than the first predetermined pressure, the open state of the volume switching valve, that is, the communication state between the first delivery pipe and the second delivery pipe can be maintained.

  Further, as the valve body operating means, as in the third aspect of the present invention, when the first delivery pipe becomes equal to or higher than the second predetermined pressure, power is supplied to open the volume switching valve, and the first and second valves are operated. The delivery pipe may be configured to include an electromagnet that stops the energization when the delivery pipe becomes lower than the first predetermined pressure. Further, as the valve body actuating means, as in the invention of claim 4, the first delivery pipe is energized to close the volume switching valve until the first delivery pipe reaches the second predetermined pressure or higher after the engine is started, and the first delivery pipe is operated. You may comprise with the electromagnet which stops the said electricity supply, when a pipe becomes more than 2nd predetermined pressure.

  Further, as the valve body operating means, the volume switching is performed by the pressure of the fuel from the first delivery pipe by communicating the first delivery pipe and the valve chamber of the volume switching valve as in the invention of claim 5. A communication passage that applies a pressing force to the valve body of the valve, and a permanent magnet that attracts the valve body of the volume switching valve in the same direction as the pressing direction of the communication passage. Then, an elastic member and a permanent magnet that apply a pressing force to the valve body of the volume switching valve in a direction opposite to the pressing direction of the communication passage are provided when the first delivery pipe reaches a second predetermined pressure or higher. The total force of the pressing force of the communication path and the magnetic force of the permanent magnet when the air gap is maximum becomes larger than the pressing force, and when the first and second delivery pipes become lower than the first predetermined pressure, You may set so that the pressing force of an elastic member may become larger than the total force of pressing force and the magnetic force of a permanent magnet without an air gap.

  According to the fuel injection device of the present invention, at the time of starting the engine until the first delivery pipe reaches the second predetermined pressure or higher, the pressure increase time of the fuel pressure can be shortened by using only the first delivery pipe. During normal driving, fuel pressure pulsation can be reduced by continuously injecting fuel from the total volume of the first and second delivery pipes until the first and second delivery pipes become lower than the first predetermined pressure.

  Embodiments of a fuel injection device according to the present invention will be described below in detail with reference to the drawings. The present invention is not limited to the embodiments.

  First Embodiment A fuel injection device according to a first embodiment of the present invention will be described with reference to FIGS.

  First, the configuration of the fuel injection device according to the first embodiment will be described.

  As shown in FIG. 1, the fuel injection device of the first embodiment includes a fuel injection valve 10 that directly injects fuel into a combustion chamber of an internal combustion engine (not shown), and a fuel supply means 20 that supplies fuel to the fuel injection valve 10. The fuel supply means 20 is provided with a high-pressure pump 30 for pressurizing and feeding fuel sent from a fuel tank (not shown). Here, since a fuel injection device that supplies fuel to an internal combustion engine having four combustion chambers is illustrated, this fuel injection device includes four fuel injection valves 10.

  Here, the fuel injection device further includes a low-pressure feed pump (not shown) disposed in the fuel tank, and the fuel pressurized to the feed pressure by the low-pressure feed pump is pumped to the high-pressure pump 30. The high-pressure pump 30 has a metering and pressure-feeding mechanism that adjusts the amount of fuel delivered, and is driven by a cam (not shown) that is interlocked with a camshaft (not shown) of the internal combustion engine, and will be described later. Alternatively, the fuel pressure in the first and second delivery pipes 21A and 21B is maintained at a desired high pressure state.

  Hereinafter, the fuel supply means 20 of the first embodiment will be described in detail.

  First, the fuel supply means 20 is provided with a first delivery pipe 21A to which the fuel pumped from the high-pressure pump 30 is supplied, and a second delivery pipe 21B communicating with the first delivery pipe 21A.

  The first and second delivery pipes 21A and 21B are set so that the total volume of the respective volumes becomes the volume of the delivery pipe generally required according to the required performance of the internal combustion engine. That is, when the fuel injection device of the first embodiment is applied to an internal combustion engine provided with only one delivery pipe, the volume of the one delivery pipe and the first embodiment of the first embodiment. The total volume of the first and second delivery pipes 21A and 21B is made equal.

  Specifically, in the first embodiment, in order to shorten the fuel pressurization time at the time of starting the engine, as will be described later, at the time of starting the engine, fuel is injected from only the first delivery pipe 21A. 10 and is switched by a volume switching valve 22 which will be described later so that fuel is supplied to the fuel injection valve 10 using the total volume of the first and second delivery pipes 21A and 21B during normal driving thereafter. For this reason, the volumes of the first and second delivery pipes 21A and 21B are set so that the volume of the first delivery pipe 21A is sufficient to satisfy the demand of the internal combustion engine at the time of starting the engine. The remaining volume that satisfies the volume required during normal driving is allocated to the second delivery pipe 21B. In the first embodiment, the first and second delivery pipes 21A and 21B are exemplified as having the same volume, but the respective volumes are not necessarily limited to such a mode. Instead, the volume of the first delivery pipe 21A may be larger or smaller than the volume of the second delivery pipe 21B as long as the fuel pressure increase time at the time of starting the engine is satisfied.

  Here, the first and second delivery pipes 21A and 21B are preferably arranged in parallel in the longitudinal direction. Thereby, the fuel injection device of the first embodiment can be constructed with the same size as the fuel injection device provided with the conventional delivery pipe.

  In the first embodiment, the fuel pumped from the high-pressure pump 30 is supplied to the first delivery pipe 21A, and the high-pressure fuel is supplied from the first delivery pipe 21A to the fuel injection valve 10. Constitute.

  Further, the fuel supply means 20 of the first embodiment is provided with a volume switching valve 22 for communicating or blocking between the first delivery pipe 21A and the second delivery pipe 21B. The volume switching valve 22 switches between fuel injection using only the volume of the first delivery pipe 21A and fuel injection using the total volume of the first and second delivery pipes 21A and 21B.

  For example, the volume switching valve 22 of the first embodiment has a cylindrical valve chamber 22a, a valve body 22b that is disposed in the valve chamber 22a and reciprocates in the axial direction, and the valve body 22b. An elastic member 22c such as a string-wound spring that applies a pressing force to shut off the first delivery pipe 21A and the second delivery pipe 21B is provided.

  Here, the closed state is a state in which the first delivery pipe 21A and the second delivery pipe 21B are blocked because the pressing force of the elastic member 22c to the valve body 22b overcomes the pressing force of the valve body actuating means 23 described later. The state in which the first delivery pipe 21A and the second delivery pipe 21B communicate with each other because the pressing force of the valve body actuating means 23 on the valve body 22b overcomes the pressing force of the elastic member 22c is referred to as a valve opening state. .

  The volume switching valve 22 of the first embodiment is opened when the valve body actuating means 23 applies a pressing force equal to or higher than the first predetermined pressure to the valve body 22b, while the pressing force of the valve body actuating means 23 is The elastic member 22c is set so that the valve is closed when is lower than the first predetermined pressure. The first predetermined pressure is a lower limit pressure of the control pressure of the injected fuel during normal driving required for the fuel injection device.

  Here, a minute gap is formed between the inner peripheral surface of the valve chamber 22a and the outer peripheral surface of the valve body 22b in order to smooth the reciprocating movement of the valve body 22b. An annular O-ring 22d is disposed on each of the outer peripheral surfaces of both end sides of the valve body 22b so as to avoid the leakage of fuel. The first and second delivery pipes 21A and 21B of the first embodiment are arranged so as to communicate with the gaps between the respective O-rings 22d.

Further, a circumferential annular groove (hereinafter referred to as “annular groove”) 22b ₁ is provided between the O-rings 22d on the outer peripheral surface of the valve body 22b of the first embodiment, and the valve chamber 22a An annular space A is formed between the inner peripheral surface. The volume switching valve 22 of the first embodiment connects the first delivery pipe 21A and the second delivery pipe 21B via the annular space A according to the position with respect to the valve chamber 22a when the valve body 22b reciprocates. Communicate or block.

Accordingly, the annular groove 22b ₁ communicates the first delivery pipe 21A and the annular space A in the valve-closed state, and connects the first and second delivery pipes 21A and 21B in the annular space in the valve-opened state. It forms so that it may communicate via A. Therefore, in the valve closed state, the fuel in the first delivery pipe 21A does not flow to the second delivery pipe 21B via the annular space A. On the other hand, in the valve open state, the fuel in the first delivery pipe 21A flows to the second delivery pipe 21B via the annular space A.

Further, inside the valve body 22b of the first embodiment, the chamber B on the elastic member 22c side in the valve chamber 22a and the gap on the outer peripheral surface side described above (the O-ring 22d and the annular groove 22b ₁ on the elastic member 22c side) A leak passage 22b ₂ is formed to communicate with the gap between the _two . The leak passage 22b ₂ communicates the chamber B with the second delivery pipe 21B in the valve-closed state shown in FIGS. 1 and 2, and the chamber B in the valve-opened state shown in FIG. A gap-side opening is formed at a position where the pipe does not directly communicate with the delivery pipes 21A and 21B (that is, a position hidden by the inner peripheral surface of the valve chamber 22a).

As a result, the leak passage 22b ₂ can make the internal pressure of the second delivery pipe 21B the same as the pressure in the chamber B (return pressure to the feed) in the valve closed state. When the fuel in the delivery pipe 21A leaks into the second delivery pipe 21B through the gap, it is possible to avoid an increase in the internal pressure of the second delivery pipe 21B. For this reason, the fuel that has leaked into the second delivery pipe 21B flows into the communication passage 23a of the valve body actuating means 23 described later, and pushes the valve body 22b of the volume switching valve 22 to open the valve. Can be prevented.

On the other hand, in the valve open state, the opening on the gap side of the leak passage 22b ₂ is hidden by the inner wall surface of the valve chamber 22a, so that there is almost no fuel leakage into the leak passage 22b ₂ . However, when the internal combustion engine stops in the open state, the fuel in the second delivery pipe 21B gradually flows into the leak passage 22b ₂ through the gap and is discharged into the room B. The internal pressures of the first and second delivery pipes 21A and 21B and the communication path 23a are reduced. Therefore, when the internal pressure of the communication passage 23a decreases and the force on the valve body 22b due to the internal pressure becomes smaller than the pressing force of the elastic member 22c, the valve body 22b is closed. Can be made.

  Further, the volume switching valve 22 is operated in the valve opening direction so that the volume switching valve 22 remains open until the first delivery pipe 21A becomes lower than the first predetermined pressure. A valve body actuating means 23 is provided. The valve body actuating means 23 includes a communication passage 23a that allows the first delivery pipe 21A and the valve chamber 22a of the volume switching valve 22 to communicate with each other, and the first delivery pipe 21A when the first delivery pipe 21A reaches a second predetermined pressure or higher. There is provided an opening / closing valve 23b for communicating the one delivery pipe 21A with the communication passage 23a.

  The communication passage 23a communicates with the valve member 22b in the valve chamber 22a on the opposite side to the elastic member 22c. For this reason, when the first delivery pipe 21A becomes the second predetermined pressure or higher and the on-off valve 23b is opened, fuel flows into the valve chamber 22a from the first delivery pipe 21A via the communication passage 23a. The valve body 22b is pushed against the pressing force of the elastic member 22c by the pressure. The second predetermined pressure is a set pressure of the injected fuel required for the fuel injection device when the engine is started, and a value larger than the first predetermined pressure described above is set.

  Further, the communication passage 23a extends to the second delivery pipe 21B so as to communicate with the inside of the valve chamber 22a and the second delivery pipe 21B. For this reason, the fuel that has flowed into the communication path 23a from the first delivery pipe 21A is sent to the second delivery pipe 21B. Therefore, if the fuel is immediately sent to the second delivery pipe 21B, the internal pressure of the communication path 23a is lower than the first predetermined pressure described above, and the volume switching valve 22 cannot be opened. There is a possibility. Even if such a decrease in internal pressure does not occur, if the flow rate of the fuel in the communication passage 23a is high, the internal pressure in the communication passage 23a becomes unstable, and the volume switching valve 22 becomes smooth. Therefore, there is a possibility that the capacity of the delivery pipe cannot be smoothly switched between when the engine is started and when the engine is normally driven.

Therefore, on the downstream side (second delivery pipe 21B side) of the on-off valve 23b and the valve chamber 22a in the communication path 23a of the first embodiment, the fuel flow suppression means 23a ₁ that reduces the flow rate of the fuel flowing through the communication path 23a. Is provided. For example, a throttle formed in the communication path 23a is used as the fuel flow suppressing means 23a ₁ . Therefore, the fuel that has flowed into the communication passage 23a when the on-off valve 23b is opened is less likely to flow downstream from the fuel flow suppression means 23a ₁ . As a result, the internal pressure of the communication passage 23a when the on-off valve 23b is opened can be stably raised without lowering than the first predetermined pressure, so that the responsiveness of the valve opening operation of the volume switching valve 22 can be increased. As a result, the capacity of the delivery pipe can be switched smoothly (from the first delivery pipe 21A to the first and second delivery pipes 21A and 21B).

Further, for example, as the on-off valve 23b of the first embodiment, until the second predetermined pressure is reached, the valve body 23b ₁ is pressed by the elastic member 23b ₂ such as a string spring to close the communication passage 23a, and the first predetermined valve is closed. A pilot valve is used that opens the communication passage 23a by pushing the valve body 23b ₁ against the pressing force of the elastic member 23b ₂ by the pressure when the pressure exceeds the pressure. For this reason, the elastic member 23b ₂ is prepared and disposed so as to contract when a force by the second predetermined pressure is applied to the valve body 23b ₁ .

Here, the valve chamber 22a of the first embodiment are return passage 22a ₁ for communicating the aforementioned chamber B and the feed is provided, the fuel that has flowed into the chamber B is sent to the feed.

The second delivery pipe 21B of the first embodiment, communicates with the feed through the return passage 21B _1, the safety valve 24 is disposed in the return passage 21B _1. The safety valve 24 is cracked or damaged in the first and second delivery pipes 21A, 21B, etc. that may occur when the internal pressure of the first and second delivery pipes 21A, 21B exceeds the upper limit pressure during normal driving. It is for avoiding.

For example, the safety valve 24, until it reaches a third predetermined pressure is closed the return passage 21B ₁ by pressing the valve body 24a by an elastic member 24b such as a helical spring, that when it becomes a third predetermined pressure or more utilizing a pilot valve to open the return passage 21B ₁ valve body 24a against the pressing force of the elastic member 24b by the pressure is pushed. For this reason, the elastic member 24b is prepared and disposed so as to contract when a force by the third predetermined pressure is applied. Further, the third predetermined pressure is set to a value lower than the upper limit pressure at which the first and second delivery pipes 21A, 21B, etc. can crack.

  The fuel injection device described above operates as follows.

First, when the engine is started, the fuel F pumped from the high pressure pump 30 is supplied only to the first delivery pipe 21A having a smaller volume than the conventional one, as shown in FIG. For this reason, the pressure increase time of the fuel F at the time of starting the engine is faster than before, so that the high-pressure fuel can be injected from the fuel injection valve 10 with high accuracy at an early stage. Here, the fuel F from the high-pressure pump 30 is also filled in the annular space A. At that time, since the second delivery pipe 21B is in communication with the chamber B through the leak passage 22b _2, the first delivery pipe 21A of the fuel communication passage 23a be leaked from the gap to the second delivery pipe 21B The pressure does not increase, and the volume switching valve 22 is not opened.

Subsequently, when the fuel F continues to be supplied from the high-pressure pump 30 and the internal pressure of the first delivery pipe 21A reaches the above-described second predetermined pressure (for example, 6 MPa), as shown in FIG. the valve body 23b ₁ and 23b is pushed communication passage 23a is opened. Thereby, the fuel F of the first delivery pipe 21A flows into the communication passage 23a and is sent to the valve chamber 22a and the second delivery pipe 21B. Along with this, the internal pressure of the communication passage 23a becomes equal to or higher than a first predetermined pressure (for example, 1 MPa), and the valve body 22b of the volume switching valve 22 is pushed against the pressing force of the elastic member 22c. .

Here, since the fuel flow suppressing means (throttle) 23a ₁ is provided in the communication path 23a as described above, the fuel F does not immediately flow into the second delivery pipe 21B. Therefore, the internal pressure upstream of the fuel flow suppression means 23a ₁ in the communication passage 23a can be stabilized, so that the valve body 22b can be opened while the internal pressure is maintained at or above the first predetermined pressure. Responsiveness can be improved.

  As described above, when the volume switching valve 22 is opened, the first and second delivery pipes 21A and 21B communicate with each other through the annular space A as shown in FIG. 4, and the fuel F of the first delivery pipe 21A flows. Supplied to the second delivery pipe 21B. As a result, the high pressure fuel is injected from the fuel injection valve 10 in the total volume of the first and second delivery pipes 21A and 21B having a larger volume than that at the time of engine start during normal driving. At this time, since the internal pressures of the first and second delivery pipes 21A and 21B and the communication passage 23a are smaller than the first predetermined pressure, the on-off valve 23b is closed.

The fuel F injection using the total volume of the first and second delivery pipes 21A and 21B is maintained until the engine is stopped. Upon engine stop, the fuel F of the second delivery pipe 21B is discharged from the leak passage 22b ₂ to the indoor B of the valve chamber 22a, the internal pressure of the first and second delivery pipes 21A, 21B and the communication passage 23a Will go down. When the internal pressure of the communication path 23a becomes smaller than the first predetermined pressure, the volume switching valve 22 is closed by the pressing force of the elastic member 22c, and oil tight leakage can be prevented.

  Next, the specific shape and configuration of the fuel supply means 20 in the above-described fuel injection device will be described in detail with reference to FIG.

  In the fuel supply means 20 shown in FIG. 5, a first valve chamber constituting member 22A having a cylindrical inner space with one end opened and a second valve chamber constituting member 22B closing the opening via a gasket 22C. For example, an internal space formed by fitting them is used as the valve chamber 22a. A valve body 22b is disposed in the valve chamber 22a, and an elastic member 22c is disposed in the chamber B formed between the valve body 22b and the second valve chamber constituting member 22B. 22 is configured.

Here, a return passage 22a ₁ for communicating the chamber B with the feed is formed inside the second valve chamber constituting member 22B.

In addition, first and second delivery passages 22A ₁ and 22A ₂ communicating with the first and second delivery pipes 21A and 21B, respectively, are formed inside the first valve chamber constituting member 22A. For example, the first and second delivery pipes 21A and 21B are fitted in the first and second delivery passages 22A ₁ and 22A ₂ , for example.

The The valve body 22b shown in FIG. 5, both ends respectively O-ring 22d is arranged in the outer peripheral surface, the circumferential direction of the annular groove 22b ₁ during the respective O-ring 22d is formed. A leak passage 22b ₂ is formed inside the valve body 22b.

Here, a first fuel passage 22b ₃ that penetrates both ends in the axial direction is formed inside the valve body 22b. In the valve body 22b shown in FIG. 5, passage diameter has become thicker at both ends of the first fuel passage 22b _3, the valve body 23b ₁ on each of its large-diameter portion, 24a and the elastic member 23b _2, 24b is Has been placed. Then, its large-diameter portion of the first fuel passage 22b _3, on-off valve 23b and the elastic member holding member 23b _3, 24c for holding the elastic member 23b _2, 24b of each of the safety valve 24 are respectively fitted. That is, here, the opening / closing valve 23b and the safety valve 24 are arranged at both ends inside the valve body 22b.

Further, a recess 22b ₄ is formed on the end face of the valve body 22b on the on-off valve 23b side, and a through hole 23b _{4 for} communicating the recess 22b ₄ with a space where the elastic member 23b ₂ in the on-off valve 23b is disposed. Is formed on the elastic member holding body 23b _{3 of the} on-off valve 23b. Further, the inside of the valve body 22b, and the second fuel passage 22b ₅ communicating with the recess 22b _4, a third fuel passage 22b ₆ communicating with the second fuel passage 22b _5, the third fuel passage A fourth fuel passage 22b ₇ is formed which communicates with 22b ₆ and also communicates with the second delivery pipe 21B.

That is, here, the annular space A, a sixth fuel passage 22b ₉ , a first fuel passage 22b _{3 to be} described later, a through hole 23b _{4 of the} elastic member holder 23b ₃ , a recess 22b ₄ and the bottom surface of the valve chamber 22a are enclosed. space, the second fuel passage 22b _5, the communication passage 23a, which is constituted by a third fuel passage 22b _6, and the fourth fuel passage 22b ₇ is formed on the inside of the valve body 22b. Further, the third fuel passage 22b ₆ is formed to have a narrower passage diameter than the second and fourth fuel passages 22b ₅ and 22b _{7 at} both ends thereof, and the above-described fuel flow suppression means (throttle) 23a ₁ is provided. I'm doing it.

Furthermore, the inside of the valve body 22b, a fifth fuel which communicates with the fourth fuel passage 22b ₇ via a gap in the circumferential direction between the inner and outer circumferential surfaces of the valve body 22b of the valve chamber 22a A passage 22b ₈ is formed. The fifth fuel passage 22b ₈ communicates with the space where the elastic member 24b of the safety valve 24 is disposed via the leak passage 22b ₂ . Further, a through hole 24c ₁ is formed in the elastic member holding body 24c of the safety valve 24 so as to communicate the space with the room B. The outer peripheral surface of the opening of the valve body 22b in the fourth fuel passage 22b ₇ here is directly communicated to the second delivery pipe 21B in a closed state of the volume switching valve 22, the volume switching valve 22 It is provided at a position hidden by the inner peripheral surface of the valve chamber 22a in the opened state. Thus, it is possible to provide the same effects as described above with respect to leak passage 22b _2.

Further, a sixth fuel passage 22b ₉ that communicates between the on-off valve 23b and the safety valve 24 in the first fuel passage 22b ₃ and the inside of the annular groove 22b ₁ (annular space A) is formed inside the valve body 22b. Provided. For this reason, the fuel of the first delivery pipe 21 fed from the high-pressure pump 30 is sent to the first fuel passage 22b ₃ via the annular space A and the sixth fuel passage 22b ₉ , and the second is started when the engine is started. When the predetermined pressure is reached, the on-off valve 23b can be opened.

In the fuel supply means 20 shown in FIG. 5 configured as described above, the fuel sent from the high-pressure pump 30 to the first delivery pipe 21A passes through the annular space A and the sixth fuel passage 22b ₉ to form the first fuel. sent to the passage 22b _3. Here, at the time of engine startup, the internal pressure of the first fuel passage 22b ₃ does not open on-off valve 23b is to reach a second predetermined pressure, the fuel is not supplied only to only the first delivery pipe 21A, the fuel Boosting time is shortened.

Subsequently, the internal pressure of the first fuel passage 22b ₃ is when it becomes more than the second predetermined pressure is close valve 23b flows out fuel into the recess 22b ₄ are opened, the recess 22b ₄ and the valve chamber 22a The valve body 22b of the volume switching valve 22 is pushed against the pressing force of the elastic member 22c by the fuel pressure in the space surrounded by the bottom surface. As a result, the first and second delivery pipes 21A and 21B communicate with each other via the annular space A, and the fuel of the first delivery pipe 21A is supplied to the second delivery pipe 21B. The fuel pressure pulsation during normal driving can be reduced, and the fuel F can be injected with high accuracy. The on-off valve 23b is closed because the internal pressure of the first fuel passage 22b ₃ becomes smaller than the first predetermined pressure.

Thus, the space surrounded by the recess 22b ₄ and the bottom surface of the valve chamber 22a functions as a pressure control chamber that pushes and opens the valve body 22b of the volume switching valve 22. The rise time of the pressure in that space can be adjusted depending on the thickness of the diameter of the third fuel passage (throttle) 22b _6. Therefore, in order to improve the responsiveness during opening of the volume switching valve 22, it is preferable to achieve an appropriate thickness of the diameter of the third fuel passage (throttle) 22b _6.

Next, when the engine is stopped from this state, the fuel F of the second delivery pipe 21B passes through the fifth fuel passage 22b ₈ , the leak passage 22b ₂ , the space of the safety valve 24 and the through hole 24c ₁ of the elastic member holder 24c. Is discharged into the room B of the valve chamber 22a. This because, first and second delivery pipe 21A, the internal pressure of 21B is reduced, the pressure in the recess 22b ₄ also decreases as this, the pressure of the recess 22b ₄ is smaller than the first predetermined pressure Sometimes the volume switching valve 22 closes to prevent oil tight leakage.

  As described above, according to the fuel injection device of the first embodiment, when the engine is started, the fuel F can be supplied only to the first delivery pipe 21A to shorten the pressure increase time of the fuel pressure. Sometimes the total volume of the first and second delivery pipes 21A, 21B having a larger volume than when the engine is started can be used, so that fuel pressure pulsation during normal driving is reduced and fuel F is injected with high accuracy. be able to.

  Further, since the fuel F can be injected using the total volume of the first and second delivery pipes 21A and 21B having a large volume until the engine is stopped, the fuel in the first and second delivery pipes 21A and 21B is injected. Even if the pressure decreases, the fuel pressure pulsation during normal driving can continue to be reduced until the pressure drops to the first predetermined pressure, and the lower limit of the fuel pressure during injection can be lowered.

  Further, in the first embodiment, since the volume switching valve 22 mechanically configured such as a pilot valve is used, a fuel injection device that achieves the effects as in the first embodiment can be constructed at low cost. Can do.

  Further, by consolidating the respective configurations as shown in FIG. 5 described above into the volume switching valve 22, the physique of the fuel injection device can be reduced and the increase in cost can be suppressed.

  Next, a second embodiment of the fuel injection device according to the present invention will be described with reference to FIG.

  The fuel injection device of the second embodiment is obtained by changing the fuel supply means 20 in the first embodiment as follows, and is otherwise configured in the same manner as the first embodiment.

In the above-described first embodiment, directly to the second delivery pipe 21B a gap side between the inner and outer circumferential surfaces of the valve body 22b of the valve chamber 22a in leak passage 22b ₂ during the closing of the volume switch valve 22 Therefore, the flow of fuel from the first delivery pipe 21A to the second delivery pipe 21B is prevented, and the opening operation of the volume switching valve 22 before the opening / closing valve 23b is opened is suppressed.

However, the effect of suppressing the opening operation of the volume switching valve 22 does not necessarily have to be obtained by the leak passage 22b ₂ , and is formed by the valve chamber 22a and the valve body 22b of the volume switching valve 22 shown in FIG. The taper seal portion 25 can also be used.

  The taper seal portion 25 is formed on a circumferential taper portion 25a formed on the outer circumferential surface of the valve body 22b, and an inner circumferential surface of the valve chamber 22a that locks the taper portion 25a in the valve closing direction of the valve body 22b. It is comprised by the formed latching | locking part 25b.

The tapered portion 25a of the valve body 22b is provided above the annular groove 22b ₁ so that fuel does not flow out from the annular space A to the second delivery pipe 21B via a gap when the volume switching valve 22 is closed. Specifically, as the taper portion 25a, the upper outer diameter of the valve body 22b is made larger than the lower side, and the boundary portion thereof is inclined inwardly and downwardly from the upper outer peripheral surface side. Provided. Here, the upper end surface of the annular groove 22b ₁ is formed in such a tapered shape and used as the tapered portion 25a.

Further, the locking portion 25b of the valve chamber 22a locks the tapered portion 25a when the volume switching valve 22 is closed so that the fuel does not flow out from the annular space A to the second delivery pipe 21B via the gap. the first delivery pipe 21A and provided between (between the first delivery passage 22A ₁ and the second delivery passage 22A ₂₎ and the second delivery pipe 21B. Specifically, as the locking portion 25b, the valve chamber 22a is formed into a stepped shape in which the inner diameter on the second delivery pipe 21B side is larger than that on the first delivery pipe 21A side, and the boundary portion is used.

  Further, in the second embodiment, when the volume switching valve 22 is closed, the valve body 22b is correctly closed by the locking portion 25b of the valve chamber 22a so that the tapered portion 25a of the valve body 22b is correctly locked. The outer shapes of the valve body 22b and the valve chamber 22a are formed so that the lower surface of the valve body 22a does not contact the bottom surface of the valve chamber 22a.

  According to the second embodiment, since the fuel does not leak from the annular space A to the second delivery pipe 21B through the gap by the taper seal portion 25 until the on-off valve 23b is opened, the on-off valve 23b is opened. The valve opening operation of the volume switching valve 22 before the valve can be prevented, and the shortening of the fuel pressurization time when the engine is started can be firmly established.

Incidentally, when the on-off valve 23b flows into the fuel into the recess 22b ₄ are opened, since the valve element 22b of volume switching valve 22 is pushed by separating and a tapered portion 25a and the engaging portion 25b upward, From that time, fuel in the annular space A can flow into the second delivery pipe 21B, and fuel injection using the first and second delivery pipes 21A and 21B during normal driving can be performed.

  Here, the taper seal portion 25 may be provided with an annular seal member on both or either one of the taper portion 25a and the locking portion 25b. The fuel leakage can be effectively avoided.

Further, when the taper seal portion 25 is provided, it is not necessary to suppress the valve opening operation of the volume switching valve 22 before the opening / closing valve 23b is opened using the leak passage 22b ₂ as in the first embodiment. By using both, leakage of fuel to the second delivery pipe 21B when the volume switching valve 22 is closed can be more effectively suppressed, and these may be used in combination.

  Next, a third embodiment of the fuel injection device according to the present invention will be described with reference to FIG.

  The fuel injection device of the third embodiment is configured by changing the fuel supply means 20 in the first embodiment as follows, and is otherwise configured in the same manner as the first embodiment.

In the first embodiment described above, the on-off valve 23b is set to be opened when the second predetermined pressure is reached, whereby the valve body 22b is moved by the fuel pressure flowing into the communication passage 23a (recess 22b ₄ ). The volume switching valve 22 is opened by being pushed. Further, when the engine is stopped, the volume switching valve 22 is closed by discharging the fuel from the leak passage 22b ₂ to the room B.

However, since the volume switching valve 22 of the first embodiment performs the opening / closing operation using the increase / decrease change of the fuel pressure in the recess 22b _4, there is a limit in improving the responsiveness at the time of opening / closing.

  Therefore, in the third embodiment, the response at the time of opening and closing is improved by using the volume switching valve 122 shown in FIG.

  In the volume switching valve 122 of the third embodiment, the opening / closing valve 23b is removed from the volume switching valve 22 of the first embodiment shown in FIG. 5, and an electromagnet (valve body operating means) 123 shown in FIG. An opening / closing operation is executed.

  Specifically, the volume switching valve 122 forms a valve chamber 22a by a first valve chamber constituting member 22A similar to that of the first embodiment and a second valve chamber constituting member 122B shown in FIG. The valve body 122b and the elastic member 22c of Example 3 are arranged.

  Here, the second valve chamber constituting member 122B of the third embodiment has the same shape as the second valve chamber constituting member 22B of the first embodiment, and an annular electromagnet 123 is formed inward of the chamber B side. Is embedded. An energization circuit (not shown) is connected to the electromagnet 123, and an electronic control unit (ECU) (not shown) that switches energization / non-energization to the electromagnet 123 with respect to the energization circuit is provided.

Further, since the valve body 122b of the third embodiment does not require the opening / closing valve 23b as in the first embodiment, the opposite side of the safety valve 24 in the inner first fuel passage 122b ₃ (opening / closing in the first embodiment) side was arranged a valve 23b) is to be occluded by the lower sixth fuel passage 22b _9. Further, in the valve body 122b, the second fuel passage 22b ₅ , the third fuel passage (throttle) 22b ₆ and the fourth fuel passage 22b ₇ constituting the communication passage 23a of the first embodiment are not required.

  The valve body 122b is configured to be attracted to the second valve chamber constituting member 122B side by electromagnetic induction when the electromagnet 123 is energized. For example, the valve body 122b may be formed of a metal material, a magnetic material, or the like, or may be configured by embedding a metal member, a magnetic body, or the like.

  By the way, in the third embodiment, when the first delivery pipe 21A becomes equal to or higher than the second predetermined pressure, the electronic control device issues an energization instruction to the energization circuit, while the electronic control device is stopped when the engine is stopped. Thus, a deenergization instruction is executed for the energization circuit. The electronic control unit can detect whether or not the engine is stopped, for example, from an ignition OFF signal or the like. However, an additional pressure detection unit or the like must be provided to determine whether or not the first delivery pipe 21A is equal to or higher than the second predetermined pressure. Cannot be detected.

Therefore, the first delivery pipe 21A of the third embodiment is provided with a pressure sensor 126 that detects the internal pressure. The pressure sensor 126 may be provided in the first fuel passage 122b ₃ and the sixth fuel passage 22b ₉ that are always in communication with the first delivery pipe 21A.

  In the fuel injection device according to the third embodiment configured as described above, fuel is supplied from the high-pressure pump 30 only to the first delivery pipe 21A when the engine is started until the first delivery pipe 21A reaches the second predetermined pressure. The

  When the electronic control unit detects that the first delivery pipe 21A has become the second predetermined pressure or more based on the detection signal of the pressure sensor 126, the electronic control unit instructs the energization circuit to energize the electromagnet 123. To energize. Thereby, electromagnetic induction is caused and the valve body 122b is attracted toward the second valve chamber constituting member 122B against the pressing force of the elastic member 22c, and the first and second delivery pipes 21A and 21B are annular. Communicates through space A.

  When the electronic control unit detects an engine stop, the electronic control unit issues a non-energization instruction to the energization circuit to stop energization of the electromagnet 123. Thereby, the valve body 122b is pulled away from the second valve chamber constituting member 122B side by the pressing force of the elastic member 22c, so that the volume switching valve 122 is closed.

  As described above, according to the fuel injection device of the third embodiment, not only the same effect as the first embodiment described above but also the responsiveness of the opening / closing operation of the volume switching valve 122 is further improved. Capacitance switching (switching from the first delivery pipe 21A to the first and second delivery pipes 21A and 21B) can be performed more smoothly.

  Incidentally, the volume switching valve 122 using the electromagnet 123 as in the third embodiment may be configured as follows.

  For example, in the above configuration, the elastic member 22c is disposed between the bottom surface of the valve chamber 22a and the lower surface of the valve body 122b, and the first and second delivery pipes 21A and 21B communicate with each other through the annular space A. The state that is in the initial state. Furthermore, the electromagnet 123 is disposed at the bottom of the valve chamber 22a.

  Then, when the engine is started, the electromagnet 123 is energized to lower the valve body 122b toward the bottom surface of the valve chamber 22a against the pressing force of the elastic member 22c, and the first and second delivery pipes 21A and 21B. Release the communication status. Thereby, the fuel can be injected only by the first delivery pipe 21A when the engine is started. On the other hand, when it is detected that the first delivery pipe 21A is equal to or higher than the first predetermined pressure, the energization of the electromagnet 123 is stopped and the valve body 122b is raised by the pressing force of the elastic member 22c. Thereby, the first and second delivery pipes 21A and 21B communicate with each other, and fuel can be injected using the total volume.

  In this way, by reversing the operation of the elastic member 22c and the electromagnet 123 from the above configuration, not only the effect of the third embodiment described above can be obtained, but also the electromagnet 123 is energized only at the time of engine start. Therefore, power consumption can be reduced.

  Next, a fourth embodiment of the fuel injection device according to the present invention will be described with reference to FIG.

  The fuel injection device of the fourth embodiment is the same as that of the first embodiment except that the fuel supply means 20 in the first embodiment is changed as follows without using the on-off valve 23b as in the third embodiment. It is configured.

As shown in FIG. 8, the volume switching valve 222 of the fourth embodiment includes a second fuel passage 22 b ₅ that constitutes the on-off valve 23 b and the communication path 23 a of the first embodiment from the volume switching valve 22 of the first embodiment shown in FIG. 5. The third fuel passage 22b ₆ (throttle) and the fourth fuel passage 22b ₇ are removed, and the opening / closing operation of the valve body 222b is executed by the permanent magnet 223 and the communication path constituting the valve body operating means.

  Specifically, the volume switching valve 222 includes a first valve chamber constituent member 22A similar to that of the first embodiment and a second valve chamber constituent member 222B shown in FIG. The valve body 222b and the elastic member 22c of Example 4 are arranged.

  Here, the second valve chamber constituting member 222B of the fourth embodiment has the same shape as the second valve chamber constituting member 22B of the first embodiment, and an annular permanent magnet 223 is formed on the lower surface of the chamber B side. Is provided.

  Further, the valve body 222b of the fourth embodiment is configured to be attracted to the second valve chamber constituting member 222B side by the magnetic force of the permanent magnet 223. For example, the valve body 222b may be formed of a magnetic material, or may be configured by applying a magnetic body to at least the end surface on the room B side.

In addition, the inside of the valve body 222b, Example 1 in the same manner as the safety valve 24 is one disposed on the interior side B, the opposite side is formed a first fuel passage 222b ₃ which opens into the recess 22b ₄ . The first fuel passage 222b ₃ communicates with the first delivery pipe 21A via the sixth fuel passage 22b ₉ and the annular space A as in the first embodiment. Therefore, in the fourth embodiment, the first space is surrounded by the annular space A, the sixth fuel passage 22b ₉ , the first fuel passage 222b ₃ and the recess 22b ₄ and the bottom surface of the valve chamber 22a. A communication path that communicates between the delivery pipe 21A and the valve chamber 22a is formed.

By the way, in the fourth embodiment, in order to maintain the closed state of the volume switching valve 222 when the engine is started and when the engine is stopped, the valve body 222b is configured such that the magnetic force of the permanent magnet 223 and the concave portion 22b when the engine is started. ₄ is prevented from moving in the valve opening direction by the fuel pressure in the space surrounded by the bottom surface of the valve chamber 22a.

  Here, the magnetic force of the permanent magnet 223 decreases with the square of the air gap as the air gap increases. For this reason, the magnetic force of the permanent magnet 223 does not act on the valve body 222b when the valve body 222b is closed by increasing the amount of movement of the valve body 222b and sufficiently increasing the air gap. Therefore, the valve body 222b is arranged so that the air gap becomes sufficiently large so that the magnetic force of the permanent magnet 223 does not act, and when the first delivery pipe 21A becomes the second predetermined pressure or more, the elastic member 22c is pushed. The elastic member 22c is set so that the pressing force of the fuel in the communication path is larger than the pressure.

  As a result, when the engine is started until the first delivery pipe 21A reaches the second predetermined pressure, the pressing force of the elastic member 22c overcomes the pressing force of the fuel in the communication path, and the valve body 222b is held in the closed state. In addition, the fuel can be injected using the volume of only the first delivery pipe 21A. Further, when the first delivery pipe 21A becomes equal to or higher than the second predetermined pressure, the pressing force of the fuel in the communication path can overcome the pressing force of the elastic member 22c and move the valve body 222b in the valve opening direction. The fuel can be injected using the total volume of the first and second delivery pipes 21A and 21B.

  Since the magnetic force of the permanent magnet 223 acts on the valve body 222b when the volume switching valve 222 is opened, even if the pressing force of the fuel in the communication path becomes smaller than the force related to the second predetermined pressure. The valve open state can be maintained.

  Furthermore, in the fourth embodiment, the pressing force of the elastic member 22c and the magnetic force of the permanent magnet 223 in the valve open state (that is, in the state without an air gap) are set to be equal. Thereby, the volume switching valve 222 can move the valve body 222b in the valve closing direction when the pressing force of the elastic member 22c overcomes the magnetic force of the permanent magnet 223 when the engine is stopped.

  In place of this, the elastic member 22c and the permanent magnet 223 of the fourth embodiment have a force obtained by subtracting the tensile force due to the magnetic force of the permanent magnet 223 in the valve-opened state from the pressing force of the elastic member 22c. You may set so that it may become the pressing force of the fuel of the communicating path by the 1st predetermined pressure shown by ~ 3. As a result, when the engine is stopped and the first and second delivery pipes 21A and 21B become smaller than the first predetermined pressure, the volume switching valve 222 causes the pressing force of the elastic member 22c to be the magnetic force of the permanent magnet 223. The valve body 222b can be moved in the valve closing direction by overcoming the combined force of the fuel pressure in the communication passage.

  As described above, according to the fuel injection device of the fourth embodiment, not only the same effect as in the first embodiment is achieved, but also the responsiveness of the opening / closing operation of the volume switching valve 222 is further improved. Therefore, the capacity of the delivery pipe can be switched more smoothly (switching from the first delivery pipe 21A to the first and second delivery pipes 21A and 21B).

  As described above, the fuel injection device according to the present invention is useful as a technique for increasing the fuel pressure at the time of starting the engine and reducing the fuel pressure pulsation during normal driving.

It is a conceptual diagram which shows the structure of Example 1 of the fuel-injection apparatus which concerns on this invention. It is a figure which shows the state at the time of engine starting in the fuel-injection apparatus of Example 1. FIG. It is a figure which shows the state at the time of the switching start from the engine starting time at the time of a normal drive in the fuel-injection apparatus of Example 1. FIG. It is a figure which shows the state at the time of the normal drive in the fuel-injection apparatus of Example 1. FIG. It is a figure which shows the specific example of a structure of Example 1 of the fuel-injection apparatus which concerns on this invention. It is a figure which shows the specific example of a structure of Example 2 of the fuel injection apparatus which concerns on this invention. It is a figure which shows the specific example of a structure of Example 3 of the fuel injection apparatus which concerns on this invention. It is a figure which shows the specific example of a structure of Example 4 of the fuel injection apparatus which concerns on this invention.

Explanation of symbols

10 fuel injection valve 20 fuel supply means 21A first delivery pipe 21B second delivery pipe 22, 122, 222 volume switching valve 22a valve chamber 22b, 122b, 222b valve body 22b ₁ annular groove 22b ₂ leak passage 22b _3, 122b _3, 222b ₃ 1st fuel passage 22b ₄ Recess 22b ₅ 2nd fuel passage 22b ₆ 3rd fuel passage 22b ₇ 4th fuel passage 22b ₈ 5th fuel passage 22b ₉ 6th fuel passage 22c Elastic member 23 Valve element operation means 23a Communication passage 23a ₁ Fuel flow suppression means (throttle)
23b On-off valve 23b ₁ Valve body 23b ₂ Elastic member 25 Taper seal part 25a Taper part 25b Locking part 30 High-pressure pump 123 Electromagnet 223 Permanent magnet A Annular space B Indoor

Claims (5)

  A first predetermined pressure is supplied between the first delivery pipe to which fuel pumped from the high pressure pump is supplied, the second delivery pipe communicating with the first delivery pipe, and the first delivery pipe and the second delivery pipe. A volume switching valve provided with a valve element that operates to shut off when the pressure is lower than the first delivery pipe, and the first delivery pipe when the first delivery pipe becomes higher than a second predetermined pressure higher than the first predetermined pressure. The volume switching valve is opened to allow communication between the first delivery pipe and the second delivery pipe, and the volume switching valve is opened until the first and second delivery pipes become lower than the first predetermined pressure. A fuel injection device comprising: a valve body actuating means for maintaining a state; and a fuel injection valve to which fuel is supplied from the first delivery pipe. The valve body actuating means includes a communication passage that communicates the first delivery pipe and the valve chamber of the volume switching valve, and the first delivery pipe when the first delivery pipe reaches the second predetermined pressure or more. And an on-off valve that communicates with the communication path,
The fuel injection device according to claim 1, wherein the communication passage is extended to communicate with the second delivery pipe.   The valve body actuating means is energized to open the volume switching valve when the first delivery pipe reaches or exceeds the second predetermined pressure, and the first and second delivery pipes are the first predetermined pipe. The fuel injection apparatus according to claim 1, further comprising an electromagnet that stops the energization when the pressure becomes lower than the pressure.   The valve body actuating means is energized to close the volume switching valve until the first delivery pipe becomes equal to or higher than the second predetermined pressure after the engine is started, and the first delivery pipe is equal to or higher than the second predetermined pressure. The fuel injection device according to claim 1, further comprising an electromagnet that stops the energization when the value becomes. The valve body operating means communicates the first delivery pipe with the valve chamber of the volume switching valve, and applies a pressing force to the valve body of the volume switching valve with the pressure of fuel from the first delivery pipe. And a permanent magnet that attracts the valve body of the volume switching valve in the same direction as the pressing direction of the communication path,
An elastic member and a permanent magnet that apply a pressing force to the valve body of the volume switching valve in a direction opposite to the pressing direction of the communication path are the elastic members when the first delivery pipe reaches or exceeds the second predetermined pressure. The total force of the pressing force of the communication path and the magnetic force of the permanent magnet when the air gap is maximum becomes larger than the pressing force of the member, and the first and second delivery pipes become lower than the first predetermined pressure. 2. The fuel injection according to claim 1, wherein the pressing force of the elastic member is set to be larger than the total force of the pressing force of the communication path and the magnetic force of the permanent magnet when there is no air gap. apparatus.

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