JP5252314B2 - High pressure pump - Google Patents

Description

  The present invention relates to a high-pressure pump used in an internal combustion engine (hereinafter referred to as “engine”).

  Conventionally, a fuel supply device that supplies fuel to an engine is provided with a high-pressure pump that pumps high-pressure fuel. The fuel rail connected to the injector accumulates the high-pressure fuel pumped from the high-pressure pump. That is, the fuel is injected from the injector by maintaining the pressure in the fuel rail.

  However, abnormal pressure increase exceeding the allowable range may occur in the fuel rail due to, for example, a failure of a metering valve included in the high pressure pump. In this case, the fuel rail and the injector may be damaged. Therefore, conventionally, a high-pressure pump provided with a relief valve that opens when the pressure in the fuel rail becomes an abnormal pressure has been proposed (see, for example, Patent Documents 1 to 3).

JP 2004-138062 A Special table 2002-515565 gazette Japanese Patent Publication No. 4-56145

However, in Patent Documents 1 and 2, there is a possibility that a sufficient valve opening pressure cannot be obtained from the fuel when the relief valve is opened. For example, in Patent Document 1, the relief valve is a ball valve, and the pressure receiving area is only a spherical seat surface. For example, in patent document 2, the pressure-receiving surface where a fuel acts at the time of valve opening is a taper. Therefore, in any case, a sufficient valve opening pressure cannot be obtained after the valve is opened, and the valve is closed at an early stage. As a result, when an abnormal pressure increase of the fuel rail occurs, the amount of fuel necessary for pressure reduction cannot flow.
Moreover, in the said patent document 3, the O-ring is provided in the sliding part of the relief valve. For this reason, it may take time until the relief valve is fully opened. As a result, when an abnormal pressure increase of the fuel rail occurs, the pressure cannot be quickly reduced.
In Patent Documents 1 to 3, the pressure in the fuel rail is lowered when a predetermined pressure exceeding the allowable range is reached, and no function is performed when the pressure in the fuel rail is within the allowable range. However, even if the pressure in the fuel rail is within the allowable range, there are concerns about the following problems.

(1) Problems caused by increased pressure in the fuel rail when the engine is stopped If the engine is stopped due to ignition OFF, etc., the engine cooling water circulates and the engine room temperature rises once immediately after the engine is stopped. Then, it goes down. For this reason, the pressure in the fuel rail also begins to rise immediately after the engine stops. Such an increase in pressure in the fuel rail leads to fuel leakage from the injector into the cylinder. As a result, the fuel leaking into the cylinder may be discharged into the atmosphere as an unburned component at the next engine start.

(2) Failure due to maintenance of pressure in the fuel rail during operation of the engine When the accelerator opening is less than the predetermined value, such as when the accelerator pedal is not depressed during operation, the engine speed is higher than the predetermined value. The fuel injection is stopped. At this time, the pressure in the fuel rail is maintained.
Thereafter, at the time of deceleration recovery such as switching to idle operation, the injector is controlled to suppress the fuel injection amount. For example, a drive pulse having a relatively small width is output to the injector. However, since the pressure in the fuel rail is maintained, the fuel injection amount may increase even if the drive pulse is adjusted. Such fuel injection more than necessary may cause deterioration in fuel consumption and an uncomfortable feeling to the driver.

  Up to this point, there have been problems due to the pressure in the fuel rail rising or being maintained at a high pressure. That is not to say that the pressure in the fuel rail should be low. Even if the pressure in the fuel rail falls too much, there are concerns about the following problems.

(3) Failure due to a drop in pressure in the fuel rail at high temperature restart After engine stop, for example, several tenths of a minute has passed, restarting the engine after high temperature restart requires a certain amount of injection Become. Therefore, if the pressure in the fuel rail decreases too much, for example, if the pressure in the fuel rail decreases to near the saturated vapor pressure of the fuel, fuel vapor is generated in the fuel rail, and the injection amount of the injector is insufficient and restart performance. May get worse.

(4) Malfunction due to pressure drop in fuel rail when restarting after idling stop As with the above high-temperature restarting, a certain amount of injection and immediate starting are possible when restarting after idling stop in a hybrid system, etc. Good spraying of the injector is required. Therefore, also in this case, if the pressure in the fuel rail falls too much, the restart performance may be deteriorated.

  The present invention has been made to solve the above-described problems, and its purpose is to lower the pressure as quickly as possible when the pressure in the fuel rail becomes a relief pressure exceeding the allowable range. An object of the present invention is to provide a high-pressure pump which can be appropriately maintained by lowering the pressure in the fuel rail as appropriate.

  In the high-pressure pump according to claim 1, which is made to achieve the above object, the pressurizing section has a pressurizing chamber. The pressurizing chamber changes its volume by the movement of the plunger and can pressurize the fuel. The discharge unit discharges the fuel pressurized in the pressurizing chamber to a fuel rail to which the injector is connected via a discharge valve.

Under such a configuration, the present invention includes a return flow path, a mechanical relief valve, and a mechanical constant residual pressure valve. The mechanical type is intended to exclude electromagnetic valves.
The return flow path is a flow path capable of returning fuel from the downstream side of the discharge valve to the upstream side of the discharge valve. The downstream side of the discharge valve means, for example, the downstream side of the valve seat if the discharge valve has a valve seat. Similarly, the upstream side of the discharge valve means the upstream side of the valve seat. The fuel may be returned upstream of the discharge valve, and includes not only returning to the high pressure fuel passage but also returning to the low pressure fuel passage disposed on the upstream side.

  The relief valve has a relief valve element. The relief valve body has a cylindrical shape, and forms an inner flow path and an outer flow path as flow paths interposed in the middle of the return flow path. Specifically, since it has a cylindrical shape, an inner flow path is formed inside the valve body, and an outer flow path is formed outside the valve body (for example, a part of the outer periphery). When the pressure in the fuel rail becomes higher than the relief pressure exceeding the allowable range, the relief valve element moves to open the outer flow path, and the return flow path functions. Here, in particular, in the present invention, the pressure receiving portion that projects to the outer flow path is a relief valve body so that the pressure receiving area that receives pressure in the valve opening direction when the outer flow path is opened is larger than when the valve is closed. Is provided.

  On the other hand, the constant residual pressure valve is supported by the inner flow path of the relief valve element. This constant residual pressure valve includes a throttle portion having a relatively small channel area on the upstream side of the inner channel. Then, the inner flow path is opened by the pressure of the fuel flowing in from the throttle portion, and the return flow path functions. The constant residual pressure valve closes the inner flow path when the pressure in the fuel rail falls below a predetermined constant residual pressure.

Next, the effect by the structure of this invention is demonstrated. Here, the effect of the constant residual pressure valve will be described first, and then the effect of the relief valve will be described.
In the present invention, the internal flow path is opened by the pressure of the fuel flowing in from the throttle portion, and the return flow path functions by the mechanical constant residual pressure valve. At this time, since the constant residual pressure valve includes the throttle portion, the pressure does not drop suddenly. Thereby, the pressure in the fuel rail can be lowered appropriately. As a result, (1) the problem caused by the increase in pressure in the fuel rail when the engine is stopped, and (2) the problem caused by maintaining the pressure in the fuel rail during operation of the engine can be eliminated. .

  Further, in the present invention, when the pressure in the fuel rail becomes equal to or lower than a predetermined constant residual pressure, the inner flow path is closed by the mechanical constant residual pressure valve. Thereby, the pressure in a fuel rail can be maintained appropriately. As a result, the above (3) failure due to a decrease in pressure in the fuel rail at the time of high temperature restart and (4) failure due to a decrease in pressure in the fuel rail at the time of restart after idle stop can be eliminated. it can.

  Conventionally, when a mechanical relief valve is used, there is a problem that the valve opening time is short and the pressure in the fuel rail cannot be lowered sufficiently. This is because after the relief valve is opened, if the pressure acting on the relief valve suddenly decreases, the pressure in the fuel rail is closed before the pressure in the fuel rail is sufficiently lowered.

  In contrast, in the present invention, when the pressure in the fuel rail exceeds the allowable pressure by the mechanical relief valve, the relief valve body moves to open the outer flow path, thereby opening the return flow path. Works. In addition, the relief valve body is provided with a pressure receiving portion that projects to the outer flow path. That is, the pressure receiving area that receives pressure in the valve opening direction when the outer flow path is opened is larger than that at the time of valve closing. Thus, once the relief valve is opened, the relief valve can be quickly moved in the valve opening direction, and the valve opening period can be maintained for a long time. As a result, the pressure in the fuel rail can be lowered as quickly as possible.

  Furthermore, in the present invention, since the constant residual pressure valve is supported inside the relief valve body, space and the like are reduced and the degree of freedom in design is reduced compared to a case where the relief valve and the constant residual pressure valve are completely different from each other. Becomes higher. In particular, providing the pressure receiving portion that projects to the outer flow path as described above is consistent with the idea of securing a space inside. In other words, the pressure receiving portion is provided with a certain width in the radial direction, but the constant residual pressure valve is disposed inside by actively utilizing the wide portion.

  In the present invention, since the relief valve and the constant residual pressure valve are mechanical, it is advantageous in that a control configuration is not required as compared with the case of using an electromagnetically controlled valve.

  According to the second aspect, since the pressure receiving portion has a pressure receiving surface that is substantially perpendicular to the moving direction of the relief valve body, the resistance due to the fuel increases, and the relief valve can be moved quickly in the valve opening direction. This contributes to keeping the relief valve open for a long time.

  According to the third aspect of the present invention, since the pressure receiving surface is concave so as to be easily subjected to resistance by the fuel, the resistance by the fuel can be further increased, and the relief valve can be quickly moved in the valve opening direction. This contributes to keeping the relief valve open for a long time.

  According to the fourth aspect, since the pressure receiving surface has a groove formed in the circumferential direction so as to be easily subjected to resistance by the fuel, the resistance by the fuel can be further increased, and the relief valve can be quickly opened. It can be moved in the valve direction, and contributes to maintaining a long valve opening period of the relief valve. At this time, the groove may be formed concentrically or may be a spiral. In addition, although it was set as the groove | channel here, it is good also as "it has the convex line | wire formed in the circumferential direction so that a pressure receiving surface may receive the resistance by a fuel easily."

  According to claim 5, the pressure receiving portion has a pressure receiving chamber. The fuel flows into the pressure receiving chamber when the outer flow path is opened by the relief valve element. As a result, the resistance due to the fuel can be further increased, the relief valve can be moved quickly in the valve opening direction, and the valve opening period of the relief valve can be maintained longer.

  It is conceivable that such a pressure receiving chamber is surrounded by an outer peripheral wall constituting a part of the pressure receiving portion. In this case, the pressure receiving chamber is a cylindrical space formed around the axis of the relief valve element.

  Assuming that the pressure receiving chamber is a cylindrical space, as shown in claim 7, the bottom surface portion of the pressure receiving chamber may be inclined so as to be easily subjected to fuel resistance. Here, the bottom surface portion refers to an inner surface portion on the side far from the opening. For example, the bottom portion becomes deeper away from the opening as it goes in the radially outward direction. In this way, the resistance due to the fuel can be further increased, and the above-described effect is conspicuous.

  In consideration of utilizing the flow of fuel, as shown in claim 8, when the outer flow path is opened by the movement of the relief valve body, the flowing fuel collides with the inner surface of the outer peripheral wall. May be. In this way, the relief valve can be quickly moved in the valve opening direction using the fuel flow. In this case, as shown in claim 9, the fuel that flows in from the start of the movement of the relief valve body until the relief valve body moves to the extent that the valve opening is ensured is the inner surface of the outer peripheral wall. It is conceivable to adopt a configuration that continues to collide with. Thus, the fuel flow can be used until the relief valve element is reliably opened. As a result, the relief valve can be quickly moved in the valve opening direction, and it contributes to keeping the relief valve open for a long time.

  According to a tenth aspect of the present invention, the pressure receiving portion is formed by attaching a member different from the relief valve body to the relief valve body. This makes it easier to form the pressure receiving portion than when the relief valve body is processed to form the pressure receiving portion.

  According to the eleventh aspect, the relief valve body has a tapered surface that causes a centripetal action on the relief valve body by the flow of fuel when the valve is opened. If it does in this way, the valve body for relief will be centered by the flow of fuel, and the axial deviation of the valve body for relief can be suppressed.

  By the way, it has already been described that the return flow path only needs to return the fuel to the upstream side of the discharge valve. However, considering the pump efficiency, it is desirable that the return flow path communicates the downstream side of the discharge valve and the pressurizing chamber as shown in claim 12.

  In this way, the constant residual pressure valve can be closed by the balance between the fuel pressure in the pressurization chamber and the pressure in the fuel rail, and the pressure in the pressurization chamber is relatively relative to the pressurization stroke of the high-pressure pump by the plunger. During the period when the pressure increases, the constant residual pressure valve is kept closed. Thereby, the discharge of the fuel by a return flow path is suppressed, and the fall of pump efficiency can be suppressed.

  In addition, the structure which comprises the said throttle part becomes effective also at the point which suppresses the fall of pump efficiency. In general, the reciprocating cycle of the plunger is increased during low-speed operation or startup, so that the repetition cycle of the pressurizing stroke is increased. For this reason, there is a concern that the pump efficiency may be reduced, but the configuration including the throttle portion can suppress the rapid return of the fuel, and in particular, suppress the decrease in pump efficiency during low speed operation and start-up. Can do.

  Hereinafter, modes for carrying out the invention will be described. In the following, the realization of claims 1, 2, and 12 is referred to as a first embodiment, and the realization of claims 1, 2, 11, and 12 is referred to as second and third embodiments. To 12 is a fourth embodiment, claims 1, 2, 3, 10, 11, 12 is a fifth embodiment, and claims 1, 5, 6, 8, 12 are realized. The sixth embodiment, the realization of claims 1, 5 to 8, and 12 is the seventh embodiment, the realization of claims 1, 2, 4, and 12 is the eighth embodiment, and claims 1, 5, The realization of 6, 8, 9, 12 is the ninth embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
The fuel supply apparatus of this embodiment is as shown in FIG.
As shown in FIG. 1, the fuel supply device 1 includes a high-pressure pump 10 and a fuel rail 20.

  The high pressure pump 10 pressurizes the fuel supplied from the fuel tank 30 by the low pressure pump 31 and discharges it as high pressure fuel. It is the fuel rail 20 that accumulates the discharged fuel. A plurality (four in this embodiment) of injectors 21 are connected to the fuel rail 20. The high-pressure fuel accumulated in the fuel rail 20 is injected from the injector 21 by energization from an ECU (not shown). At this time, the ECU outputs a pulse signal for driving the injector. Therefore, the injection amount is controlled by the width of this pulse signal (injector drive pulse width) and the pressure in the fuel rail 20.

Next, the configuration of the high-pressure pump 10 will be described.
As shown in FIG. 1, the high-pressure pump 10 includes a plunger unit 40, a metering valve unit 50, a discharge valve unit 60, and a pressure adjustment unit 70. The outer shell of the high-pressure pump 10 is constituted by a housing 11 as shown in FIG.

  A cover 12 is attached in one direction (upward in FIG. 2) of the housing 11, and a fuel chamber 13 is formed by the cover 12 and the housing 11. A plunger portion 40 is provided on the opposite side of the cover 12. A pressurizing chamber 14 capable of pressurizing fuel is formed near the middle between the plunger portion 40 and the fuel chamber 13. Furthermore, the metering valve part 50 and the discharge valve part 60 are provided in a direction orthogonal to the direction in which the cover 12 and the plunger part 40 are arranged. Fuel is supplied to the fuel chamber 13 from the fuel tank 30 by the low-pressure pump 31 shown in FIG. The fuel supplied to the fuel chamber 13 is pumped from the discharge valve portion 60 to the fuel rail 20 shown in FIG. 1 via the metering valve portion 50 and the pressurizing chamber 14.

Next, the structure of the plunger part 40, the metering valve part 50, the discharge valve part 60, and the pressure adjustment part 70 is demonstrated in order.
First, the plunger unit 40 will be described.
The plunger part 40 includes a plunger 41, a plunger support part 42, a lifter 43, a plunger spring 44, and the like.

  The plunger 41 is supported by a cylinder 15 formed inside the housing 11. The plunger support portion 42 is disposed at the end of the cylinder 15 and supports the plunger 41 together with the cylinder 15 so as to be able to reciprocate. The plunger 41 has an outer diameter similar to the inner diameter of the cylinder 15 on the pressurizing chamber 14 side, and the diameter is smaller on the plunger support portion 42 side.

  A bottomed cylindrical lifter 43 is disposed at the end of the plunger 41. As shown in FIG. 1, the lifter 43 abuts the outer surface of a cam 101 attached to the camshaft 100, and reciprocates in the axial direction according to the cam profile by the rotation of the camshaft 100.

A plunger spring 44 is disposed inside the lifter 43. The plunger spring 44 is a return spring of the plunger 41 and biases the lifter 43 so as to contact the cam surface.
With such a configuration of the plunger portion 40, the reciprocating movement of the plunger 41 according to the rotation of the camshaft 100 is realized, and the volume change of the pressurizing chamber 14 is created.

Next, the metering valve unit 50 will be described.
As shown in FIG. 2, the metering valve unit 50 includes a cylinder part 51 formed by the housing 11, a valve part cover 52 that covers the opening of the cylinder part 51, a connector 53, a connector housing 54, and the like.
The cylinder part 51 is formed in a substantially cylindrical shape and has a fuel passage 55 inside. A substantially cylindrical seat body 56 is disposed in the fuel passage 55. A suction valve 57 is arranged inside the seat body 56. The suction valve 57 includes a disk-shaped bottom portion 571 and a cylindrical wall portion 572, and a spring 58 is accommodated in the internal space.

  The needle 59 is in contact with the bottom 571 of the suction valve 57. The needle 59 passes through the valve cover 52 described above and extends to the inside of the connector 53. The connector 53 includes a coil 531 and a terminal 532 for energizing the coil 531. Inside the coil 531, a fixed core 533, a movable core 534, and a spring 535 interposed between the fixed core 533 and the movable core 534 are disposed. Here, the needle 59 described above is fixed to the movable core 534 by welding. That is, the movable core 534 and the needle 59 are integrated.

  With this configuration, when energization is performed via the terminal 532 of the connector 53, a magnetic attractive force is generated between the fixed core 533 and the movable core 534 by the magnetic flux generated in the coil 531. As a result, the movable core 534 moves toward the fixed core 533, and accordingly, the needle 59 moves away from the pressurizing chamber 14. At this time, the movement of the suction valve 57 is not restricted by the needle 59. Accordingly, the bottom portion 571 of the suction valve 57 can be seated on the seat body 56, and the fuel passage 55 and the pressurizing chamber 14 are blocked by the seating of the suction valve 57.

  On the other hand, if energization through the terminal 532 of the connector 53 is not performed, no magnetic attractive force is generated, so that the movable core 534 is moved away from the fixed core 533 by the spring 535. Thereby, the needle 59 moves to the pressurizing chamber 14 side. As a result, the movement of the suction valve 57 is regulated by the needle 59, and the suction valve 57 is held on the pressurizing chamber 14 side. At this time, the bottom portion 571 of the intake valve 57 is separated from the seat body 56, so that the fuel passage 55 and the pressurizing chamber 14 communicate with each other.

  Next, the discharge valve unit 60 will be described. From here, please refer to FIG. 3 together with FIG. FIG. 3 is a plan view showing the high-pressure pump 10 viewed from the direction indicated by the symbol A in FIG. Here, a discharge valve portion 60 and a pressure adjusting portion 70 described later are notched.

  As shown in FIGS. 2 and 3, the discharge valve portion 60 has a cylindrical accommodating portion 61 formed by the housing 11. A discharge valve body 62, a spring 63, and a locking portion 64 are accommodated in a storage chamber 611 formed by the storage portion 61. Further, the opening portion of the storage chamber 611 is a discharge port 65. A valve seat 612 is formed in a deep portion of the accommodation chamber 611 opposite to the discharge port 65 (see FIG. 3).

  The discharge valve body 62 abuts on the valve seat 612 by the force of the urging force of the spring 63 and the pressure in the fuel rail 20. Thereby, the discharge valve body 62 stops the fuel discharge while the fuel pressure in the pressurizing chamber 14 is low. On the other hand, when the pressure of the fuel in the pressurizing chamber 14 increases to overcome the urging force of the spring 63 and the force generated by the pressure in the fuel rail 20, the discharge valve element 62 moves toward the discharge port 65. As a result, the fuel that has flowed into the storage chamber 611 is discharged from the discharge port 65. In addition, the discharge valve body 62 has a space serving as a passage for fuel therein. Therefore, when the discharge valve body 62 is separated from the valve seat 612, the fuel that has flowed into the outer peripheral portion of the discharge valve body 62 is discharged from the discharge port 65 via the internal space of the discharge valve body 62. Will be.

Next, the pressure adjustment unit 70 will be described.
As shown in FIG. 3, the pressure adjusting unit 70 is interposed in return channels 71 and 72 from the storage chamber 611 to the pressurizing chamber 14 on the downstream side of the valve seat 612 on which the discharge valve body 62 is seated. Specifically, it is interposed between the return channel 71 from the storage chamber 611 and the return channel 72 leading to the pressurizing chamber 14.

  The pressure adjusting unit 70 includes a mechanical relief valve 73 and a mechanical constant residual pressure valve 74. Next, the configuration of the relief valve 73 and the constant residual pressure valve 74 will be described. FIG. 4A is a partial enlarged cross-sectional view of the pressure adjusting unit 70. Moreover, FIG.4 (b) is the bb sectional view taken on the line of Fig.4 (a).

  As shown in FIG. 4A, the relief valve 73 is disposed in the fuel passages 75 and 76 that follow the return passage 71. The diameters of the fuel passages 75 and 76 are larger than the diameter of the return flow path 71. Further, the diameter of the downstream fuel passage 76 is larger than the diameter of the upstream fuel passage 75. The return passage 72 connects the downstream fuel passage 76 and the pressurizing chamber 14 (see FIG. 3). Further, the downstream fuel passage 76 opens to the outside of the housing 11. Therefore, the relief valve 73, the constant residual pressure valve 74, and the like are assembled using this opening. As shown in FIG. 3, the opening is closed by screwing a locking portion 77 having a hexagon bolt.

  The relief valve 73 includes a tubular relief valve body 81 and a spring 82 that biases the relief valve body 81. The relief valve body 81 has a tip portion 83, a main body portion 84 having a diameter larger than that of the tip portion 83, and a flange portion 85 that projects outward from the main body portion 84 in the radially outward direction. The diameter of the main body 84 is slightly smaller than the diameter of the upstream fuel passage 75, and the diameter of the flange portion 85 is slightly smaller than the diameter of the downstream fuel passage 76. Accordingly, the relief valve body 81 is supported by the fuel passages 75 and 76 so as to be movable in the axial direction.

  One end of the spring 82 is locked to the flange portion 85 and the other end is locked to the locking portion 77 (see FIG. 3). Furthermore, a valve seat 78 is formed at the connecting portion from the return flow path 71 to the fuel passage 75, and the relief valve body 81 urged by the spring 82 has a peripheral edge of the tip 83 at the valve seat 78. Abut.

  The relief valve element 81 is normally seated on the valve seat 78, and when the fuel pressure in the fuel rail 20 shown in FIG. The fuel pressure acting on 83 a is separated from the valve seat 78 against the biasing force of the spring 82. In other words, the urging force by the spring 82 is adjusted so that the relief valve 73 is opened above the relief pressure.

  In addition, as shown in FIG.4 (b), as for the main-body part 84 of the valve body 81 for relief, both sides in the predetermined direction perpendicular | vertical to an axis | shaft are chamfered, and the flat surface 84a is formed. As a result, an outer passage 79 is formed outside the main body 84 (relief valve element 81). Therefore, when the tip 83 of the relief valve element 81 is separated from the valve seat 78, the fuel that has flowed into the fuel passage 75 flows into the fuel passage 76 via the outer passage 79. That is, when the relief valve 73 is opened, the outer passage 79 is opened.

  Here, in particular, as shown in FIG. 4A, a pressure receiving portion 90 that receives pressure from the fuel is formed at the connecting portion between the tip portion 83 of the relief valve body 81 and the main body portion 84. Specifically, the diameter suddenly increases from the tip 83 to the main body 84, and a flat pressure receiving surface 90a is formed on the tip 83 side. As a result, only the distal end surface 83a receives pressure when the relief valve 73 is closed, but when the relief valve 73 is opened, pressure is also received on the pressure receiving surface 90a. That is, when the valve is opened, the pressure receiving area is increased.

  By the way, it has already been described that the relief valve body 81 has a cylindrical shape. At this time, as shown in FIG. 4A, an orifice 86 having a relatively small flow path area is formed at the distal end portion 83 of the relief valve element 81. Fuel passages 87 and 88 are formed on the downstream side of the orifice 86. The downstream fuel passage 88 following the upstream fuel passage 87 has a diameter larger than that of the upstream fuel passage 87. Further, a valve seat 89 is formed at a connecting portion between the fuel passage 87 and the fuel passage 88.

Here, the constant residual pressure valve 74 is disposed in the downstream fuel passage 88. As shown in FIG. 4A, the constant residual pressure valve 74 has a constant residual pressure valve body 91, a spring 92, and a locking portion 93.
The constant residual pressure valve body 91 includes a spherical tip portion 94 and a main body portion 95. One end of the spring 92 is locked to the locking portion 93 and the other end is locked to the main body portion 95. As a result, the main body 95 is biased toward the upstream fuel passage 87, and the spherical tip 94 comes into contact with the valve seat 89. Further, the engaging portion 93 is formed with a fuel passage 93a penetrating the center portion thereof.

  The constant residual pressure valve element 91 is normally separated from the valve seat 89, and when the fuel pressure in the fuel rail 20 shown in FIG. Therefore, it is seated on the valve seat 89. In other words, the urging force by the spring 92 is adjusted so that the constant residual pressure valve 74 is closed below the constant residual pressure. In this embodiment, the constant residual pressure is set to be equal to or lower than the pressure of the fuel rail 20 during idling of the engine and equal to or higher than the saturated vapor pressure of the fuel.

  Although it has already been described that the constant residual pressure valve 74 is normally opened, it is closed in the pressurizing stroke by the plunger 41 of the high-pressure pump 10 as an exception.

  Here, the pressurization stroke of the high-pressure pump 10 will be described. When the plunger 41 shown in FIG. 2 is energized to the coil 531 while moving from the bottom dead center to the top dead center, a magnetic circuit is formed by the magnetic field generated in the coil 531. Then, the needle 59 moves integrally with the movable core 534 to the fixed core 533 side. As a result, the suction valve 57 is seated on the seat body 56 by the urging force of the spring 58 and the pressure received from the fuel on the pressurizing chamber 14 side. As a result, the fuel chamber 13 and the pressurizing chamber 14 are interrupted. When the plunger 41 further rises toward the top dead center in a state where the pressurization chamber 14 and the fuel chamber 13 are blocked, the fuel pressure in the pressurization chamber 14 rises. When the fuel pressure in the pressurizing chamber 14 becomes equal to or higher than a predetermined pressure, the discharge valve body 62 of the discharge valve portion 60 moves to the discharge port 65 side as described above. Thereby, the pressurization chamber 14 and the storage chamber 611 communicate with each other, and the fuel pressurized in the pressurization chamber 14 is discharged from the discharge port 65.

  The pressurization stroke has been described above. In this pressurization stroke, the fuel pressure in the pressurization chamber 14 increases, and the fuel in the return flow path 71 on the discharge valve portion 60 side and the return flow path 72 on the pressurization chamber 14 side. The pressure difference is reduced (see FIG. 3). Accordingly, the constant residual pressure valve 74 is held in the closed state by the fuel pressure from the return flow path 72 side communicating with the pressurizing chamber 14.

  In this embodiment, the high-pressure pump 10 constitutes a “high-pressure pump”, the plunger portion 40 constitutes a “pressurizing portion”, the pressurizing chamber 14 constitutes a “pressurizing chamber”, and the discharge valve portion 60 “ The discharge valve body 62, the spring 63, the locking portion 64, and the valve seat 612 constitute a “discharge valve”. The return flow paths 71 and 72 constitute a “return flow path”, the relief valve 73 constitutes a “relief valve”, the relief valve element 81 constitutes a “relief valve element”, a fuel passage 75, 76 and 79 constitute the “outer flow path”, the fuel passages 87 and 88 constitute the “inner flow path”, the pressure receiving portion 90 constitutes the “pressure receiving portion”, and the pressure receiving surface 90a constitutes the “pressure receiving surface”. To do. Furthermore, the constant residual pressure valve 74 constitutes a “constant residual pressure valve”, and the orifice 86 constitutes a “throttle portion”.

Next, the effect produced by the high-pressure pump 10 of this embodiment will be described.
FIG. 5 is an explanatory diagram showing the transition of the pressure in the fuel rail 20. Here, it is assumed that the engine is stopped at time t1.
Since the engine is generally idled immediately before the engine is stopped, when the engine is stopped (time t1), the pressure in the fuel rail 20 is the pressure during idle operation indicated by symbol A (hereinafter referred to as “idle pressure A”). It is said).

  At this time, when the constant residual pressure indicated by symbol B (hereinafter referred to as “constant residual pressure B”) is set, the constant residual pressure valve 74 is opened except for the above-described pressurization stroke. Therefore, as indicated by symbol D in FIG. 5, the pressure in the fuel rail 20 decreases. The “tilt” at this time is determined by the orifice 86 described above (see FIG. 4A). When the pressure in the fuel rail 20 becomes the constant residual pressure B at time t2, the constant residual pressure valve 74 is closed. Thereby, as shown by the symbol E, the pressure of the fuel rail 20 is maintained constant, that is, the constant residual pressure B. Thereafter, as the fuel rail 20 cools, the pressure in the fuel rail 20 gradually decreases, and is close to the saturated vapor pressure indicated by symbol C (hereinafter referred to as “saturated vapor pressure C”) at time t3. It will be a thing.

  If there is no constant residual pressure valve 74, the pressure in the fuel rail 20 rises from when the engine is stopped (time t1), as indicated by a two-dot chain line of symbol F in FIG. Specifically, as shown in FIG. 6, when the engine speed becomes “0” at time t <b> 1, the temperature of the fuel rail 20 temporarily increases as indicated by the symbol G because the engine room is hot. After the temperature is maintained to some extent (from time t4 to time t5), the temperature falls (after time t5). Accordingly, as indicated by the symbol H, the pressure in the fuel rail 20 similarly changes. For this reason, the fuel leakage from the injector 21 is also relatively large. As indicated by the symbol I.

  On the other hand, in this embodiment, even if the temperature of the fuel rail 20 rises, the pressure in the fuel rail 20 is lowered by the constant residual pressure valve 74 as indicated by symbol J in FIG. Thereby, as shown with the symbol K, the fuel leak from the injector 21 is suppressed. Specifically, excess fuel leakage at the portion indicated by symbol R can be suppressed.

In addition, the high-pressure pump 10 according to the present embodiment is also effective in fuel cut by depression of the accelerator pedal.
FIG. 7 is an explanatory diagram showing the fuel injection amount from the injector 21 (see FIG. 1) at the time of deceleration recovery in which the operation of the accelerator pedal is interrupted during the operation of the engine and then the engine is in the idle operation state again.

  When the depression of the accelerator pedal is interrupted at time s1 in FIG. 7, the throttle opening becomes smaller than a predetermined value. At this time, if the engine speed is greater than or equal to a predetermined value, fuel injection is stopped. Thereafter, for example, when the engine speed falls below a predetermined value, the state shifts to an idling state (time s2).

  At this time, as shown in FIG. 7, in the period from time s1 to time s2 when the fuel cut is performed, the drive pulse width of the ECU output to the injector 21 is “0”. Thereafter, from time s2, in order to make the injection state of the injector 21 suitable for idle operation, a drive pulse having a relatively small width as indicated by the symbol L is output to the injector 21.

  If there is no constant residual pressure valve 74, the injection from the injector 21 is not performed during the period from time s1 to time s2, so the pressure of the fuel rail 20 is just before the fuel cut (time The pressure of s1) is maintained. For this reason, even when the drive pulse width of the injector 21 is reduced at time s2, as shown by the broken line of the symbol N, more fuel than necessary is injected due to the pressure of the fuel rail 20.

  In this regard, in the high-pressure pump 10 of this embodiment, the pressure in the fuel rail 20 can be lowered as indicated by the symbol O from the time of fuel cut (time s1 in FIG. 7) by the action of the constant residual pressure valve 74. As shown by the symbol P, the fuel injection amount from the injector 21 at time s2 can be a fuel injection amount according to the idling state. As a result, it is possible to suppress excessive injection at the time of return from deceleration, and it is possible to suppress deterioration in fuel consumption, and the driver does not feel uncomfortable due to excessive injection.

Furthermore, the configuration of the present embodiment is also effective for restarting the engine at a high temperature start or after an idle stop.
That is, as shown in FIG. 5, the constant residual pressure B is maintained from time t2, and thereafter, the pressure of the fuel rail 20 is maintained at or above the saturated vapor pressure until time t3. For example, the pressure in the fuel rail 20 is maintained for a period of 30 minutes to 1 hour after the engine is stopped. Thereby, deterioration of the restart performance at the time of high temperature restart can be suppressed. Further, in the idle stop system that temporarily stops the engine by waiting for a signal or the like, the deterioration of the restart performance can be suppressed also at the restart after the idle stop, as in the high temperature restart.

  Conventionally, when a mechanical relief valve is used, there is a problem that the valve opening time is short and the pressure in the fuel rail cannot be lowered sufficiently. This is because after the relief valve is opened, if the pressure acting on the relief valve suddenly decreases, the pressure in the fuel rail is closed before the pressure in the fuel rail is sufficiently lowered.

  On the other hand, in this embodiment, a pressure receiving portion 90 that receives pressure from the fuel is formed at the connecting portion between the tip 83 and the main body 84 of the relief valve body 81 (see FIG. 4). Thereby, when the valve is opened, the pressure receiving area is increased. In addition, a flat pressure receiving surface 90a is formed so as to easily receive pressure from the fuel. As a result, the relief valve 73 can be quickly moved in the valve opening direction, and the valve opening period of the relief valve 73 once opened can be maintained for a long time. It can be lowered as quickly as possible.

(Second Embodiment)
In this embodiment, the structure of the relief valve body is partially different from the above embodiment. FIG. 8 is a partially enlarged cross-sectional view of the pressure adjusting unit 700 of the present embodiment. Moreover, FIG.8 (b) is the bb sectional view taken on the line of Fig.8 (a). Further, FIG. 8C is a perspective view of the distal end portion of the relief valve element 810.

  Similar to the above embodiment, the relief valve 730 includes a tubular relief valve element 810 and a spring 820 that biases the relief valve element 810. The relief valve body 810 includes a tip end portion 830, a main body portion 840 having a diameter larger than that of the tip end portion 830, and a flange portion 850 that projects outward from the main body portion 840 in a radially outward direction. At this time, the spring 820 causes the relief valve element 810 to abut the peripheral edge of the tip 830 against the valve seat 780.

  The relief valve element 810 is normally seated on the valve seat 780, and is separated from the valve seat 780 when the pressure in the fuel rail exceeds the relief pressure exceeding the allowable range. Here, in particular, as shown in FIG. 8A, a pressure receiving portion 900 that receives pressure from the fuel is formed at a connection portion between the distal end portion 830 and the main body portion 840 of the relief valve body 810. The pressure receiving portion 900 has a pressure receiving surface 900a that is a flat surface as in the above embodiment, and also has a tapered surface 900b between the pressure receiving surfaces 900a formed at a predetermined interval (90 ° interval in this embodiment). Yes.

  The relief valve 730 of this embodiment constitutes a “relief valve”, the relief valve element 810 constitutes a “relief valve element”, the pressure receiving part 900 constitutes a “pressure receiving part”, and the pressure receiving surface 900 a is “ "Pressure receiving surface" is configured, and the tapered surface 900b configures "tapered surface".

Also in this embodiment, the same effect as that of the above embodiment is achieved by the function of the constant residual pressure valve.
Also in the present embodiment, a pressure receiving portion 900 that receives pressure from the fuel is formed at the connecting portion between the distal end portion 830 and the main body portion 840 of the relief valve element 810 (see FIG. 8). Thereby, when the valve is opened, the pressure receiving area is increased. Further, a flat pressure receiving surface 900a is formed so as to easily receive pressure from the fuel. As a result, the relief valve 730 can be quickly moved in the valve opening direction, and the valve opening period of the relief valve 730 once opened can be maintained for a long time. It can be lowered as quickly as possible.

  In addition, in this embodiment, a space between the pressure receiving surfaces 900a is a tapered surface 900b. As a result, the fuel flowing in from the periphery of the tip end portion 830 of the relief valve element 810 acts on the tapered surface 900b, whereby the relief valve element 810 is centered. As a result, the axial deviation of the relief valve body 810 can be suppressed.

(Third embodiment)
The present embodiment is also partially different in the structure of the relief valve body from the above embodiment. FIG. 9 is a partially enlarged cross-sectional view of the pressure adjustment unit 701 of the present embodiment.

  Similar to the above-described embodiment, the relief valve 731 includes a tubular relief valve body 811 and a spring 821 that biases the relief valve body 811. The relief valve body 811 has a distal end portion 831, a main body portion 841 having a larger diameter than the distal end portion 831, and a flange portion 851 projecting outward from the main body portion 841. At this time, the spring 821 causes the relief valve body 811 to abut the periphery of the tip 831 against the valve seat 781.

  The relief valve body 811 is normally seated on the valve seat 781 and is separated from the valve seat 781 when the pressure in the fuel rail becomes a relief pressure exceeding the allowable range. Here, in particular, as shown in FIG. 9, a pressure receiving portion 901 that receives pressure from the fuel is formed at a connecting portion between the distal end portion 831 of the relief valve body 811 and the main body portion 841. The pressure receiving portion 901 has a pressure receiving surface 901a that is a flat surface as in the above embodiment. The tip 831 has a tapered surface 831b whose diameter increases toward the downstream side.

  The relief valve 731 of this embodiment constitutes a “relief valve”, the relief valve element 811 constitutes a “relief valve element”, the pressure receiving part 901 constitutes a “pressure receiving part”, and the pressure receiving surface 901a “ "Pressure receiving surface" is configured, and the tapered surface 831b configures the "tapered surface".

Also in this embodiment, the same effect as that of the above embodiment is achieved by the function of the constant residual pressure valve.
Also in this embodiment, a pressure receiving portion 901 that receives pressure from the fuel is formed at the connecting portion between the tip 831 of the relief valve 811 and the main body 841 as in the above embodiment (see FIG. 9). Thereby, when the valve is opened, the pressure receiving area is increased. Further, a flat pressure receiving surface 901a is formed so as to easily receive pressure from the fuel. As a result, the relief valve 731 can be quickly moved in the valve opening direction, and the valve opening period of the relief valve 731 once opened can be kept long. For example, the pressure in the fuel rail that has been abnormally increased can be increased. It can be lowered as quickly as possible.

  In addition, in this embodiment, the tip 831 has a tapered surface 831b. The fuel flowing in from the periphery of the tip 831 of the relief valve body 811 acts on the tapered surface 831b, whereby the relief valve body 811 is centered. Thereby, the axial displacement of the relief valve body 811 can be suppressed.

(Fourth embodiment)
The present embodiment is also partially different in the structure of the relief valve body from the above embodiment. FIG. 10 is a partially enlarged cross-sectional view of the pressure adjusting unit 702 of the present embodiment.

  Similar to the above embodiment, the relief valve 732 includes a tubular relief valve body 812 and a spring 822 that biases the relief valve body 812. The relief valve body 812 includes a tip portion 832, a main body portion 842 having a larger diameter than the tip portion 832, and a flange portion 852 that projects outward from the main body portion 842. At this time, the spring 822 causes the relief valve body 812 to abut the periphery of the tip 832 against the valve seat 782.

  The relief valve element 812 is normally seated on the valve seat 782, and is separated from the valve seat 782 when the pressure in the fuel rail exceeds the relief pressure exceeding the allowable range. In particular, as shown in FIG. 10, a pressure receiving portion 902 that receives pressure from the fuel is provided at a connecting portion between the distal end portion 832 of the relief valve body 812 and the main body portion 842, which is different from the relief valve body 812. The member is formed. The pressure receiving portion 902 has a ring shape and has a pressure receiving surface 902a that is a flat surface as in the above-described embodiment. The tip 832 has a tapered surface 832b whose diameter increases toward the downstream side.

  Note that the relief valve 732 of this embodiment constitutes a “relief valve”, the relief valve element 812 constitutes a “relief valve element”, the pressure receiving part 902 constitutes a “pressure receiving part”, and the pressure receiving surface 902a “ "Pressure receiving surface" is configured, and the tapered surface 832b configures the "tapered surface".

Also in this embodiment, the same effect as that of the above embodiment is achieved by the function of the constant residual pressure valve.
Also in this embodiment, a pressure receiving portion 902 that receives pressure from the fuel is provided at the connecting portion between the tip portion 832 of the relief valve body 812 and the main body portion 842, as in the above embodiment (see FIG. 10). Thereby, when the valve is opened, the pressure receiving area is increased. In addition, a flat pressure receiving surface 902a is formed so as to easily receive pressure from the fuel. As a result, the relief valve 732 can be quickly moved in the valve opening direction, and the opening period of the relief valve 732 once opened can be maintained for a long time. It can be lowered as quickly as possible.

  Moreover, in this embodiment, since the pressure receiving portion 902 is a member different from the relief valve body 812, it is advantageous in that the pressure receiving portion 902 can be easily formed as compared with the case where the valve body itself is processed. .

  In addition, in this embodiment, the tip 832 has a tapered surface 832b. Therefore, the fuel that flows in from the periphery of the tip 832 of the relief valve body 812 acts on the tapered surface 832b, whereby the relief valve body 812 is centered. Thereby, the axial shift of the relief valve body 812 can be suppressed.

(Fifth embodiment)
The present embodiment is also partially different in the structure of the relief valve body from the above embodiment. FIG. 11 is a partially enlarged cross-sectional view of the pressure adjusting unit 703 of the present embodiment.

  Similar to the above-described embodiment, the relief valve 733 includes a tubular relief valve body 813 and a spring 823 that biases the relief valve body 813. The relief valve body 813 includes a front end portion 833, a main body portion 843 having a diameter larger than that of the front end portion 833, and a flange portion 853 projecting outward from the main body portion 843 in the radial direction. At this time, the spring 823 causes the relief valve body 813 to abut the peripheral edge of the tip end portion 833 against the valve seat 783.

  The relief valve element 813 is normally seated on the valve seat 783, and is separated from the valve seat 783 when the pressure in the fuel rail exceeds the relief pressure exceeding the allowable range. In particular, as shown in FIG. 11, a pressure receiving portion 903 that receives pressure from the fuel is provided at a connecting portion between the distal end portion 833 and the main body portion 843 of the relief valve body 813, which is different from the relief valve body 813. The member is formed. The pressure receiving portion 903 has a ring shape and has a pressure receiving surface 903a. In particular, the pressure receiving surface 903a of the present embodiment has a concave shape that causes the outer peripheral portion to protrude upstream so as to be easily subjected to resistance by fuel. Moreover, the front-end | tip part 833 has the taper surface 833b whose diameter becomes large toward the downstream.

  The relief valve 733 of this embodiment constitutes a “relief valve”, the relief valve element 813 constitutes a “relief valve element”, the pressure receiving portion 903 constitutes a “pressure receiving portion”, and the pressure receiving surface 903a “ “Pressure receiving surface” is configured, and the tapered surface 833b is configured as “tapered surface”.

Also in this embodiment, the same effect as that of the above embodiment is achieved by the function of the constant residual pressure valve.
Also in this embodiment, similarly to the above embodiment, a pressure receiving portion 903 that receives pressure from the fuel is provided at the connection portion between the tip portion 833 of the relief valve body 813 and the main body portion 843 (see FIG. 11). Thereby, when the valve is opened, the pressure receiving area is increased. Further, a concave pressure receiving surface 903a is formed so as to easily receive pressure from the fuel. As a result, the relief valve 733 can be quickly moved in the valve opening direction, and the opening period of the relief valve 733 once opened can be kept long. For example, the pressure in the fuel rail that has been abnormally increased can be increased. It can be lowered as quickly as possible.

  Moreover, in this embodiment, since the pressure receiving portion 903 is a member different from the relief valve body 813, it is advantageous in that the pressure receiving portion 903 can be easily formed as compared with the case where the valve body itself is processed. .

  In addition, in this embodiment, the distal end portion 833 has a tapered surface 833b. Therefore, the fuel that flows in from the periphery of the tip 833 of the relief valve body 813 acts on the tapered surface 833b, whereby the relief valve body 813 is centered. Thereby, the axial displacement of the relief valve body 813 can be suppressed.

(Sixth embodiment)
The present embodiment is also partially different in the structure of the relief valve body from the above embodiment. Further, in accordance with the relief valve body, the shape of the fuel passage and the valve seat is partially different from the above-described form. The fuel passages and valve seats have the same shape as the following. FIG. 12 is a partially enlarged cross-sectional view of the pressure adjusting unit 704 of the present embodiment.

  Similar to the above embodiment, the relief valve 734 has a relief valve body 814 that has a tubular shape. The relief valve body 814 includes a tip portion 834 extending in the axial direction and a main body portion 844 having a diameter larger than that of the tip portion 834. At this time, the relief valve element 814 brings the end edge portion of the tip end portion 834 into contact with the valve seat 784 by a spring (not shown).

  The relief valve element 814 is normally seated on the valve seat 784, and is separated from the valve seat 784 when the pressure in the fuel rail exceeds the relief pressure exceeding the allowable range. In particular, as shown in FIG. 12, the distal end portion 834 of the relief valve body 814 protrudes from the main body portion 844 in the axial direction. A pressure receiving portion 904 is formed around the protruding portion. The pressure receiving portion 904 has an outer peripheral wall 904a that surrounds the protruding portion in the circumferential direction. A space surrounded by the outer peripheral wall 904a is a pressure receiving chamber 904b. The pressure receiving chamber 904 b is a cylindrical space formed around the axis of the relief valve element 814. Thus, when the relief valve element 814 is separated from the valve seat 784, the fuel flows into the pressure receiving chamber 904b. Further, when the relief valve element 814 is separated from the valve seat 784, the fuel flows downstream from the two-dot chain line of symbol B and the fuel collides with the inner surface of the outer peripheral wall 904a.

  The relief valve 734 of this embodiment constitutes a “relief valve”, the relief valve element 814 constitutes a “relief valve element”, the pressure receiving part 904 constitutes a “pressure receiving part”, and the outer peripheral wall 904a “ The “outer peripheral wall” is configured, and the pressure receiving chamber 904b is configured as the “pressure receiving chamber”.

Also in this embodiment, the same effect as that of the above embodiment is achieved by the function of the constant residual pressure valve.
Also in this embodiment, as in the above embodiment, the pressure receiving portion 904 that projects to the outer flow path so that the pressure receiving area that receives pressure in the valve opening direction when the outer flow path is opened becomes larger than when the outer flow path is closed. have. A pressure receiving chamber 904b surrounded by the outer peripheral wall 904a of the pressure receiving portion 904 is formed. When the relief valve element 814 is separated from the valve seat 784, fuel flows into the pressure receiving chamber 904b. Further, the fuel collides with the inner surface of the outer peripheral wall 904a. As a result, the resistance due to the fuel can be further increased. As a result, the relief valve 734 can be moved quickly in the valve opening direction, and the opening period of the relief valve 734 once opened can be maintained for a long time. It can be lowered as quickly as possible.

(Seventh embodiment)
The present embodiment is also partially different in the structure of the relief valve body from the above embodiment. FIG. 13 is a partially enlarged cross-sectional view of the pressure adjustment unit 705 of the present embodiment.

  Similar to the above embodiment, the relief valve 735 includes a relief valve body 815 that has a tubular shape. The relief valve body 815 has a tip end portion 835 extending in the axial direction and a main body portion 845 having a diameter larger than that of the tip end portion 835. At this time, the relief valve element 815 brings the end edge portion of the tip end portion 835 into contact with the valve seat 785 by a spring (not shown).

  The relief valve element 815 is normally seated on the valve seat 785, and is separated from the valve seat 785 when the pressure in the fuel rail becomes a relief pressure exceeding the allowable range. Here, in particular, as shown in FIG. 13, the distal end portion 835 of the relief valve body 815 protrudes from the main body portion 845 in the axial direction. A pressure receiving portion 905 is formed around the protruding portion. The pressure receiving portion 905 has an outer peripheral wall 905a that surrounds the protruding portion in the circumferential direction. A space surrounded by the outer peripheral wall 905a is a pressure receiving chamber 905b. The pressure receiving chamber 905 b is a cylindrical space formed around the axis of the relief valve body 815. At this time, when the relief valve body 815 is separated from the valve seat 785, the fuel flows into the pressure receiving chamber 905b. Further, when the relief valve body 815 is separated from the valve seat 785, the fuel flows downstream from the two-dot chain line of symbol B and the fuel collides with the inner surface of the outer peripheral wall 905a. Here, the bottom surface portion of the pressure receiving chamber 905b is inclined and becomes deeper away from the opening toward the radially outward direction. This is as indicated by an arrow A in FIG.

  The relief valve 735 of this embodiment constitutes a “relief valve”, the relief valve element 815 constitutes a “relief valve element”, the pressure receiving part 905 constitutes a “pressure receiving part”, and the outer peripheral wall 905a “ The “outer peripheral wall” is configured, and the pressure receiving chamber 905b is configured as the “pressure receiving chamber”.

Also in this embodiment, the same effect as that of the above embodiment is achieved by the function of the constant residual pressure valve.
Also in this embodiment, as in the above embodiment, the pressure receiving portion 905 that projects to the outer flow path so that the pressure receiving area that receives pressure in the valve opening direction when the outer flow path is opened becomes larger than when the outer flow path is closed. have. A pressure receiving chamber 905b surrounded by the outer peripheral wall 905a of the pressure receiving portion 905 is formed, and when the relief valve element 815 is separated from the valve seat 785, fuel flows into the pressure receiving chamber 905b. Further, the fuel collides with the inner surface of the outer peripheral wall 905a. Furthermore, the bottom surface portion of the pressure receiving chamber 905b is inclined so as to increase the resistance of the fuel. As a result, the resistance due to the fuel can be further increased. As a result, the relief valve 735 can be quickly moved in the valve opening direction, and the opening period of the relief valve 735 once opened can be kept long. For example, the pressure in the fuel rail that has been abnormally increased can be increased. It can be lowered as quickly as possible.

(Eighth embodiment)
The present embodiment is also partially different in the structure of the relief valve body from the above embodiment. FIG. 14 is a partially enlarged cross-sectional view of the pressure adjustment unit 706 of the present embodiment.

  Similar to the above embodiment, the relief valve 736 has a relief valve body 816 that has a tubular shape. The relief valve body 816 includes a distal end portion 836 extending in the axial direction and a main body portion 846 having a diameter larger than that of the distal end portion 836. At this time, the relief valve element 816 brings the end edge portion of the tip end portion 836 into contact with the valve seat 786 by a spring (not shown).

  The relief valve element 816 is normally seated on the valve seat 786, and is separated from the valve seat 786 when the pressure in the fuel rail exceeds the relief pressure exceeding the allowable range. Here, in particular, as shown in FIG. 14, a pressure receiving portion 906 is formed at the connecting portion between the distal end portion 836 of the relief valve body 816 and the main body portion 846. The pressure receiving portion 906 has a pressure receiving surface 906a. A plurality (three in this embodiment) of grooves 906b are concentrically formed on the pressure receiving surface.

  In this embodiment, the relief valve 736 constitutes a “relief valve”, the relief valve element 816 constitutes a “relief valve element”, the pressure receiving part 906 constitutes a “pressure receiving part”, and the pressure receiving surface 906 a "Pressure-receiving surface" is constituted, and the groove 906b constitutes "groove".

Also in this embodiment, the same effect as that of the above embodiment is achieved by the function of the constant residual pressure valve.
Also in this embodiment, similarly to the above-described embodiment, the pressure receiving portion 906 that protrudes to the outer flow path so that the pressure receiving area that receives pressure in the valve opening direction when the outer flow path is opened becomes larger than when the outer flow path is closed. have. A groove 906b is formed on the pressure receiving surface 906a of the pressure receiving portion 906. As a result, the resistance due to the fuel can be further increased. As a result, the relief valve 736 can be quickly moved in the valve opening direction, and the valve opening period of the relief valve 736 once opened can be kept long. For example, the pressure in the fuel rail that has been abnormally increased can be increased. It can be lowered as quickly as possible.

  Although the groove 906a having a triangular shape in cross section is formed here, a configuration as shown in FIG. 15 may be adopted in order to increase the resistance by the fuel. Here, the relief valve 737, the relief valve body 817, the distal end portion 837, the main body portion 847, and the valve seat 787 have the same configuration. The pressure receiving portion 907 has a pressure receiving surface 907a, and a plurality (three in this embodiment) of grooves 907b are formed concentrically on the pressure receiving surface 907a. Here, in particular, the groove 907b has a quadrangular shape in sectional view. In this way, the resistance by the fuel can be further increased as compared with the groove 906b having a triangular shape in cross section. In this case, the relief valve 737 constitutes a “relief valve”, the relief valve element 817 constitutes a “relief valve element”, the pressure receiving portion 907 constitutes a “pressure receiving portion”, and the pressure receiving surface 907 a corresponds to the “pressure receiving surface”. ”And the groove 907b constitutes“ groove ”.

  Here, the plurality of grooves 906b and 907b are formed concentrically, but the grooves may be formed in a spiral shape.

(Ninth embodiment)
The present embodiment is also partially different in the structure of the relief valve body from the above embodiment. FIG. 16 is a partially enlarged cross-sectional view of the pressure adjustment unit 708 of the present embodiment.

  Similar to the above embodiment, the relief valve 738 has a relief valve body 818 having a cylindrical shape. The relief valve body 818 has a distal end portion 838 extending in the axial direction and a main body portion 848 having a diameter larger than that of the distal end portion 838. At this time, the relief valve element 818 brings the end edge portion of the tip end portion 838 into contact with the valve seat 788 by a spring (not shown). Around the valve seat 788, a conical surface 788a having a smaller taper angle than the valve seat 788 is formed.

  The relief valve body 818 is normally seated on the valve seat 788, and is separated from the valve seat 788 when the pressure in the fuel rail exceeds the relief pressure exceeding the allowable range. In particular, as shown in FIG. 16, the distal end portion 838 of the relief valve body 818 protrudes from the main body portion 848 in the axial direction. A pressure receiving portion 908 is formed around the protruding portion. The pressure receiving portion 908 has an outer peripheral wall 908a that surrounds the protruding portion in the circumferential direction. The outer peripheral wall 908a expands in the radially outward direction as it approaches the opening side. A space surrounded by the outer peripheral wall 908a is a pressure receiving chamber 908b. The pressure receiving chamber 908 b is a cylindrical space formed around the axis of the relief valve body 818. At this time, when the relief valve body 818 is separated from the valve seat 788, the fuel flows downstream from the two-dot chain line of the symbol B along the conical surface 788 a. Thereby, the flowing fuel collides with the inner surface of the outer peripheral wall 908a.

  When the relief valve element 818 moves away from the valve seat 788 and moves to the position indicated by the two-dot chain line of symbol C, the relief valve element 818 is surely opened thereafter. At this time, since the two-dot chain line of symbol B is near the upper end portion of the outer peripheral wall 908a, the fuel that flows in while the relief valve body 818 moves to the position indicated by the two-dot chain line of symbol C flows on the outer peripheral wall 908a. It will continue to collide with the inner surface.

  The relief valve 738 of this embodiment constitutes a “relief valve”, the relief valve element 818 constitutes a “relief valve element”, the pressure receiving part 908 constitutes a “pressure receiving part”, and the outer peripheral wall 908a is “ The “outer peripheral wall” is configured, and the pressure receiving chamber 908b is the “pressure receiving chamber”.

Also in this embodiment, the same effect as that of the above embodiment is achieved by the function of the constant residual pressure valve.
Also in this embodiment, similarly to the above-described embodiment, the pressure receiving portion 908 that protrudes to the outer flow path so that the pressure receiving area that receives pressure in the valve opening direction when the outer flow path is opened becomes larger than when the outer flow path is closed. have. A pressure receiving chamber 908b surrounded by the outer peripheral wall 908a of the pressure receiving portion 908 is formed. When the relief valve body 818 is separated from the valve seat 788, fuel flows into the pressure receiving chamber 908b. Further, the fuel that flows in collides with the inner surface of the outer peripheral wall 908a, and further, the fuel that flows in until the relief valve body 818 moves to a position where the valve opening is surely performed, the inner surface of the outer peripheral wall 908a. Continue to collide with. Thereby, the resistance by the fuel can be further increased. As a result, the relief valve 735 can be quickly moved in the valve opening direction to maintain the valve opening, and the valve opening period of the relief valve 735 once opened can be kept long. Can be lowered as quickly as possible.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited at all to the said form, It can implement with a various form.

It is explanatory drawing which shows the fuel supply apparatus of embodiment of this invention. It is sectional drawing which shows the structure of a high pressure pump. It is a top view which shows a part of high-pressure pump in a cross section. It is a partial expanded sectional view of the pressure adjustment part of a 1st embodiment. It is explanatory drawing which shows transition of the pressure in a fuel rail. It is explanatory drawing which shows the fuel leak from an injector by the temperature rise of a fuel rail. It is explanatory drawing which shows the fuel injection quantity from an injector at the time of the deceleration return after a fuel cut. It is a partial expanded sectional view of the pressure adjustment part of a 2nd embodiment. It is a partial expanded sectional view of the pressure adjustment part of 3rd Embodiment. It is a partial expanded sectional view of the pressure adjustment part of 4th Embodiment. It is a partial expanded sectional view of the pressure adjustment part of a 5th embodiment. It is a partial expanded sectional view of the pressure adjustment part of 6th Embodiment. It is a partial expanded sectional view of the pressure adjustment part of a 7th embodiment. It is a partial expanded sectional view of the pressure adjustment part of 8th Embodiment. It is a partial expanded sectional view of the pressure adjustment part as a modification of 8th Embodiment. It is a partial expanded sectional view of the pressure adjustment part of 9th Embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Fuel supply apparatus, 10 ... High pressure pump (high pressure pump), 11 ... Housing, 12 ... Cover, 13 ... Fuel chamber, 14 ... Pressurization chamber (pressurization chamber), 15 ... Cylinder, 20 ... Fuel rail, 21 ... Injector, 30 ... Fuel tank, 31 ... Low pressure pump, 40 ... Plunger part (pressurizing part), 41 ... Plunger, 42 ... Plunger support part, 43 ... Lifter, 44 ... Plunger spring, 50 ... Metering valve part, 51 ... Cylindrical part, 52 ... Valve part cover, 53 ... Connector, 531 ... Coil, 532 ... Terminal, 533 ... Fixed core, 534 ... Movable core, 535 ... Spring, 54 ... Connector housing, 55 ... Fuel passage, 56 ... Seat body, 57 ... Suction valve, 571 ... Bottom part, 572 ... Wall part, 58 ... Spring, 59 ... Needle, 60 ... Discharge valve part, 61 ... Storage part, 611 ... Storage room, 612 ... Seat, 62 ... Discharge valve body, 63 ... Spring, 64 ... Locking part, 65 ... Discharge port, 70 ... Pressure adjusting part, 71, 72 ... Return flow path (return flow path), 73 ... Relief valve (relief valve) ), 74 ... Constant residual pressure valve (constant residual pressure valve), 75, 76 ... Fuel passage, 77 ... Locking portion, 78 ... Valve seat, 79 ... Outer passage (outer flow path), 81 ... Relief valve element (for relief) Valve body), 82 ... spring, 83 ... tip portion, 83a ... tip surface, 84 ... main body portion, 84a ... flat surface, 85 ... flange portion, 86 ... orifice (throttle portion), 87, 88 ... fuel passage (inner flow) 89) valve seat, 90 ... pressure receiving portion (pressure receiving portion), 90a ... pressure receiving surface (pressure receiving surface), 91 ... constant residual pressure valve element, 92 ... spring, 93 ... locking portion, 93a ... fuel passage, 94 ... tip part, 95 ... body part, 100 ... camshaft, 101 ... cam, 700 701, 702, 703, 704, 705, 706, 707, 708 ... Pressure adjusting part, 730, 731, 732, 733, 734, 735, 736, 737, 738 ... Relief valve (relief valve), 780, 781, 782 , 783, 784, 785, 786, 787, 788 ... valve seat, 788a ... conical surface, 810, 811, 812, 813, 814, 815, 816, 817, 818 ... relief valve (relief valve), 820, 821, 822, 823 ... Spring, 830, 831, 832, 833, 834, 835, 836, 837, 838 ... Tip, 831b, 832b, 833b ... Tapered surface (tapered surface), 840, 841, 842, 843, 844, 845, 846, 847, 848 ... main body, 850, 851, 852, 853 ... Lung portion, 900, 901, 902, 903, 904, 905, 906, 907, 908 ... pressure receiving portion (pressure receiving portion), 900a, 901a, 902a, 903a, 906a, 907a ... pressure receiving surface (pressure receiving surface), 900b ... taper Surface (tapered surface), 904a, 905a, 908a ... outer peripheral wall (outer peripheral wall), 904b, 905b, 908b ... pressure receiving chamber

Claims (12)

A pressurizing unit having a pressurizing chamber capable of pressurizing fuel by changing the volume by movement of the plunger;
A discharge part for discharging fuel pressurized in the pressurizing chamber to a fuel rail to which an injector is connected via a discharge valve;
A return flow path capable of returning fuel from the downstream side of the discharge valve to the upstream side of the discharge valve;
It has a cylindrical relief valve body that forms an inner flow path inside the valve body and an outer flow path outside the valve body as a flow path that is interposed in the middle of the return flow path, and the pressure in the fuel rail is within an allowable range. When the relief pressure exceeds, a mechanical relief valve that opens the outer flow path by moving the relief valve body and functions the return flow path;
The throttle valve is supported by the inner flow path of the relief valve body, and has a throttle portion having a relatively small flow path area on the upstream side of the inner flow path, and the inner flow by the pressure of the fuel flowing from the throttle portion. A mechanical constant residual pressure valve that opens the path to function the return flow path, and closes the inner flow path when the pressure in the fuel rail falls below a predetermined constant residual pressure,
The relief valve body has a pressure receiving portion that protrudes to the outer flow path so that a pressure receiving area that receives pressure in the valve opening direction when the outer flow path is opened is larger than when the valve is closed. A high-pressure pump characterized by The high-pressure pump according to claim 1,
The high pressure pump, wherein the pressure receiving portion has a pressure receiving surface substantially perpendicular to a moving direction of the relief valve body. The high-pressure pump according to claim 2,
The high pressure pump, wherein the pressure receiving surface has a concave shape so as to be easily subjected to resistance by fuel. The high-pressure pump according to claim 2,
The high pressure pump, wherein the pressure receiving surface has a groove formed in a circumferential direction so as to be easily subjected to resistance by fuel. The high-pressure pump according to claim 1,
The high pressure pump, wherein the pressure receiving portion includes a pressure receiving chamber into which fuel flows when the outer flow path is opened by the relief valve body. The high-pressure pump according to claim 5,
The pressure receiving portion has an outer peripheral wall formed around the axis of the relief valve body,
The high pressure pump, wherein the pressure receiving chamber is a cylindrical space surrounded by the outer peripheral wall and formed around an axis of the relief valve body. The high-pressure pump according to claim 6,
A high-pressure pump characterized in that a bottom surface portion of the pressure receiving chamber is inclined so as to be easily subjected to fuel resistance. The high-pressure pump according to claim 7,
A high-pressure pump characterized in that when the outer flow path is opened by the movement of the relief valve body, the fuel that flows in collides with the inner surface of the outer peripheral wall. The high-pressure pump according to claim 8,
The fuel flowing in continues to collide with the inner surface of the outer peripheral wall until the relief valve body moves to the extent that the valve opening is ensured after the relief valve body starts moving. High pressure pump. In the high-pressure pump according to any one of claims 1 to 9,
The high pressure pump, wherein the pressure receiving part is formed by attaching a member different from the relief valve body to the relief valve body. In the high pressure pump according to any one of claims 1 to 10,
The high-pressure pump, wherein the relief valve body has a tapered surface that causes a centripetal action on the relief valve body by a fuel flow when the valve is opened. In the high pressure pump according to any one of claims 1 to 11,
The return flow path communicates the downstream side of the discharge valve and the pressurizing chamber.

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