JP2024010605A - electromagnetic fuel injection valve - Google Patents

Abstract

To achieve reduction of bouncing time of a movable core which impulsively contacts with a valve closing stopper when energization to a coil is interrupted in an electromagnetic fuel injection valve.SOLUTION: A valve closing side stopper 49 is fastened to a rod 43 of a valve body 40 and slidably fitted to an inner peripheral surface of a valve housing 9. The valve closing side stopper 49 is provided with orifices 50a each of which allows communication between both end surfaces. An annular contact part 51, which protrudes in an annular form concentrically with the valve closing side stopper 49 and may contact with a flat front end surface of a fixed core 14, is provided close to an outer periphery of a rear end surface of the valve closing side stopper 49.SELECTED DRAWING: Figure 2

Description

The present invention relates to an electromagnetic fuel injection valve mainly used in a fuel supply system of an internal combustion engine, and in particular, to a valve housing having a valve seat at the front end, and a hollow fixed core connected to the rear end of the valve housing. a coil disposed around the outer periphery of the fixed core; a valve element having a rod connected to a valve portion that cooperates with the valve seat; and a coil disposed on the outer periphery of the fixed core; a movable core that is slidably fitted around the outer periphery of the valve housing and allows fuel to flow within the valve housing; a valve-opening stopper that is pushed by a core to open the valve body; a valve-closing stopper that is fixed to the rod closer to the valve seat than the valve-opening stopper; and a valve-closing stopper that closes the valve body. an auxiliary spring that urges the movable core to move away from the valve-opening side stopper and come into contact with the valve-closing side stopper when the coil is de-energized; Regarding improvement of injection valves.

Such an electromagnetic fuel injection valve is already known as disclosed in Patent Document 1 below.

Patent No. 6788085

In such an electromagnetic fuel injection valve, the set load of the auxiliary spring that biases the movable core toward the valve-closing stopper side is set smaller than the set load of the valve spring that biases the valve body in the valve-closing direction. When the coil is energized, in the process of increasing the attractive force of the fixed core against the movable core, the movable core quickly resists the set load of the auxiliary spring and approaches the fixed core. immediately pushes the valve-opening stopper against the set load of the valve spring and is attracted to the fixed core, thereby opening the valve quickly. This has the advantage of increasing the valve opening response of the valve body and reducing the power consumption of the coil.

On the other hand, because the set load of the auxiliary spring that biases the movable core toward the valve-closing stopper side is small, it is difficult to cut off current to the coil when the fuel injection interval time is extremely short, such as in a multi-stage fuel injection valve. Therefore, when a bouncing phenomenon occurs in the movable core that impacts the valve-closing stopper, it may be difficult to bring it under control by the time the coil is energized for the next valve opening. If the bouncing phenomenon that occurs in the movable core continues until the next time the coil is energized, the predetermined opening stroke of the valve body will be slightly deviated, potentially affecting the fuel injection characteristics.

The present invention has been made in view of the above circumstances, and is an electromagnetic device capable of shortening the bouncing time when a bouncing phenomenon occurs in the movable core that impacts the stopper on the valve closing side when the coil is cut off. The purpose of this invention is to provide a type fuel injection valve.

In order to achieve the above object, the present invention provides a valve housing having a valve seat at the front end, a hollow fixed core connected to the rear end of the valve housing, and a hollow fixed core arranged around the outer periphery of the fixed core. a coil; a valve body having a rod connected to a valve portion that cooperates with the valve seat; A movable core that allows fuel to flow within the valve housing; and a movable core that is fixed to the rod and is pushed by the movable core to open the valve body when the fixed core attracts the movable core by energization of the coil. a valve-opening side stopper that is fixed to the rod closer to the valve seat than the valve-opening side stopper, a valve spring that biases the valve body in the valve-closing direction, and a valve spring that biases the valve body in the valve-closing direction; In the electromagnetic fuel injection valve, the electromagnetic fuel injection valve includes an auxiliary spring that urges the movable core to move away from the valve-opening side stopper and come into contact with the valve-closing side stopper when energized, wherein the valve-closing side stopper is attached to the valve housing. The valve-closing stopper has an orifice that communicates between its front and rear end surfaces, and the valve-closing stopper and the valve-closing stopper are arranged near the outer periphery of the rear end surface of the valve-closing stopper. The first feature is that the movable core is provided with an annular abutting portion that protrudes in a concentric annular shape and can abut against the flat front end surface of the movable core.

In addition to the first feature, the present invention has a second feature that the orifices are arranged in plurality at equal intervals along the circumferential direction of the valve-closing stopper.

According to the first feature of the present invention, the valve-closing stopper, which is slidably fitted into the inner circumferential surface of the valve housing, is provided with an orifice that communicates between both the front and rear end surfaces of the stopper, thereby interrupting current flow to the coil. When the movable core impacts the valve-closing stopper due to the biasing force of the auxiliary spring, causing a bouncing phenomenon, the pressure difference generated before and after the valve-closing stopper causes a reciprocating flow of fuel at the orifice. By suppressing the reciprocating flow by the damper effect of the orifice, the bouncing phenomenon of the movable core can be brought to an early end. Therefore, the bouncing time of the movable core can be significantly shortened, and even if the fuel injection interval time is short, the bouncing phenomenon can be brought to an end by the time the next coil is energized, and predetermined fuel injection characteristics can be maintained. Can be done.

Furthermore, the rear end face of the valve-closing side stopper is provided with an annular contact part near its outer periphery that can come into contact with the flat front end face of the movable core, so that when the coil is de-energized, the movable core is in an annular position in an inclined position. When contact occurs at one point on the contact part, the auxiliary spring applies a large return moment to the movable core with a large arm length between that point and the center axis of the auxiliary spring, causing the movable core to return to the annular contact. It is possible to immediately return to the proper posture in which the entire contact part is in contact, which contributes to convergence of the bouncing phenomenon of the movable core.

In addition, in the valve closed state where the entire annular contact part of the valve-closing side stopper is in contact with the flat front end surface of the movable core, the contact area where a fuel oil film is generated between the movable core and the valve-closing side stopper is This will be significantly reduced due to the contact area. Therefore, the sticking force between the movable core and the valve-closing stopper due to the fuel oil film can be substantially nullified, and the valve-opening response of the valve element can be improved when the coil is energized.

According to the second feature of the present invention, the plurality of orifices are arranged in the valve-closing stopper at equal intervals along the circumferential direction of the valve-closing stopper, so that when the fuel passes through each orifice, The moment acting on the valve-closing stopper is balanced as a whole, and the inclination of the valve-closing stopper can be suppressed.

1 is a longitudinal sectional view showing an embodiment of an electromagnetic fuel injection valve for an internal combustion engine according to the present invention. FIG. 2 is an enlarged sectional view taken along arrow 2 in FIG. 1, showing the fuel injection valve in a closed state. FIG. 3 is a sectional view taken along the line 3-3 in FIG. 2. Correspondence diagram with Fig. 2 showing the open state of the above fuel injection valve

Embodiments of the present invention will be described with reference to the accompanying FIGS. 1 to 4.

First, in FIGS. 1 and 2, the cylinder head 5 of the internal combustion engine E is provided with a mounting hole 7 that opens into the combustion chamber 6. An injection valve I is mounted in the mounting hole 7. In the electromagnetic fuel injection valve I of the present invention, the fuel injection side is the front side, and the opposite side is the rear side.

The valve housing 9 of this electromagnetic fuel injection valve I includes a hollow cylindrical housing body 10, a valve seat member 11 that fits and is welded to the inner periphery of the front end of the housing body 10, and a rear end of the housing body 10. A magnetic cylindrical body 12 is welded to the housing body 10 with its front end fitted to the outer periphery of the magnetic cylinder 12, and a non-magnetic cylindrical body 13 whose front end is coaxially connected to the rear end of the magnetic cylinder 12. Ru. A front end of a cylindrical fixed core 14 having a hollow part 15 is coaxially connected to the rear end of the non-magnetic cylindrical body 13, and a fuel supply connected to the hollow part 15 is connected to the rear end of the fixed core 14. The tubes 16 are integrally and coaxially connected.

The magnetic cylindrical body 12 has a flange-shaped yoke part 12a integrally in its axially intermediate part, and is accommodated in an annular recess 17 provided in the cylinder head 5 so as to surround the outer end of the mounting hole 7. A cushioning material 18 is interposed between the cylinder head 5 and the yoke portion 12a.

At the entrance of the fuel supply cylinder 16, an orifice member 24 and a fuel filter 19 located downstream thereof are installed. A fuel supply cap 21 branched from a fuel distribution pipe 20 connected to a discharge port of a fuel pump (not shown) is fitted into the fuel supply tube 16 via an annular seal member 22 . A bracket 23 is secured to the top of the fuel supply cap 21, and this bracket 23 is removably fastened to the cylinder head 5 using an appropriate fixing means (for example, a bolt) to a support (not shown) that is installed upright on the cylinder head 5. be done.

An elastic member 26 made of a leaf spring is interposed between the fuel supply cap 21 and an annular stepped portion 25 provided in the middle of the fuel supply cylinder 16 and facing the fuel supply cap 21 side. The electromagnetic fuel injection valve I is held in the cylinder head 5 by the elastic force exerted by the elastic member 26.

The valve seat member 11 has a bottomed cylindrical shape with an end wall portion 11a at the front end, and a conical valve seat 27 is formed on the end wall portion 11a. A plurality of fuel nozzle holes 28 are provided that open near the center of the fuel injection hole 27 . The valve seat member 11 is fitted and welded to the front end of the housing body 10 so that the fuel injection hole 28 opens toward the combustion chamber 6. That is, the valve housing 9 is configured to have a valve seat 27 at its front end.

A coil assembly 30 is fitted onto the outer peripheral surface of the magnetic cylindrical body 12 from the rear end to the fixed core 14 . This coil assembly 30 consists of a bobbin 31 that fits on the outer peripheral surface, and a coil 32 that is wound around the bobbin 31. The front end of a magnetic coil housing 33 that surrounds this coil assembly 30 is It is combined with the magnetic cylinder 12.

The outer periphery of the rear end of the fixed core 14 is covered with a synthetic resin coating layer 34 that is molded so as to be continuous with the rear end of the coil housing 33 . A coupler 34a holding the electromagnetic fuel injection valve I is integrally formed so as to protrude from one side thereof.

The rear end of the non-magnetic cylindrical body 13 is fitted into the annular recess on the outer periphery of the front end of the fixed core 14 so that its outer peripheral surface is connected to the fixed core 14, and welded in a liquid-tight manner.

A portion of the valve body 40 and a movable core 41 are accommodated in the valve housing 9 extending from the valve seat member 11 to the non-magnetic cylindrical body 13. The valve body 40 includes a valve portion 42 that opens and closes the fuel injection hole 28 in cooperation with the valve seat 27, and a rod 43 that extends into the fixed core 14. The valve portion 42 is formed into a spherical shape so as to slide within the valve seat member 11, and the rod 43 is formed to have a smaller diameter than the valve portion 42. An annular fuel passage 44 is defined between the valve seat member 11 and the rod 43, and a plurality of flat parts 45 are formed on the outer circumferential surface of the valve portion 42 to define fuel passages between the valve seat member 11 and the rod 43. be done. Therefore, the valve seat member 11 allows fuel to pass through while guiding the opening and closing operations of the valve body 40.

The movable core 41 slides and rotates on the inner circumferential surface of the valve housing 9 and the outer circumferential surface of the rod 43, with its rear end surface (suction surface 41a) facing the front end surface (suction surface 14a) of the fixed core 14. Possibly fitted. Therefore, an annular gap 56a is provided between the outer circumferential surface of the movable core 41 and the inner circumferential surface of the valve housing 9, and an annular gap 56b is provided between the inner circumferential surface of the movable core 41 and the outer circumferential surface of the rod 43, respectively. Furthermore, the movable core 41 is arranged astride the magnetic cylindrical body 12 and the non-magnetic cylindrical body 13.

In order to regulate the sliding stroke of the movable core 41 on the rod 43 to a constant value, a valve-opening side stopper 48 and a valve-closing side stopper 49 that are arranged to sandwich the movable core 41 are fixed to the rod 43 by welding. At this time, the valve-opening side stopper 48 faces the suction surface 41a of the movable core 41, which is opposite to the fixed core 14, and the valve-closing side stopper 49 faces the suction surface 41a of the movable core 41. They are arranged so as to be able to abut and face the front end surface on the opposite side.

When the valve body 40 is in the closed state (see FIG. 2), the movable core 41 is in contact with the valve-closing stopper 49 and has a gap between it and the valve-opening stopper 48 corresponding to the sliding stroke. They face each other with an interval, and this interval, that is, the sliding stroke is set smaller than the interval provided between the movable core 41 and the fixed core 14 that are in contact with the valve-closing stopper 49. Therefore, when the fixed core 14 attracts the movable core 41 as the coil 32 is energized, the movable core 41 first contacts the valve-opening side stopper 48 and then is attracted to the fixed core 14.

The valve opening side stopper 48 is composed of a flange portion 48a that is slidably fitted to the inner circumferential surface of the fixed core 14, and a cylindrical shaft portion 48b that protrudes from the flange portion 48a toward the movable core 41 side. . The flange portion 48a is fixed to the rod 43 by welding, and a portion of the shaft portion 48b protrudes toward the movable core 41 side than the suction surface 14a when the valve body 40 is in the closed position.

Referring again to FIGS. 1 and 2, a pipe-shaped retainer 53 is fitted into the hollow portion 15 of the fixed core 14 and fixed by caulking. A valve spring 54 is compressed between the retainer 53 and the flange portion 48a of the valve-opening stopper 48, and urges the valve body 40 in the seating direction on the valve seat 27, that is, in the valve-closing direction.

Further, an auxiliary spring 55 that surrounds the shaft portion 48b of the valve-opening side stopper 48 is compressed between the flange portion 48a of the valve-opening side stopper 48 and the movable core 41. This auxiliary spring 55 is given a set load smaller than the set load of the valve spring 54, and urges the movable core 41 to move away from the valve-opening side stopper 48 and come into contact with the valve-closing side stopper 49. .

The rear end of the rod 43 protrudes beyond the flange 48a of the valve-opening stopper 48, fits into the inner peripheral surface of the movable end of the valve spring 54, and plays a positioning role. Further, the shaft portion 48b of the valve-opening side stopper 48 fits into the inner circumferential surface of the auxiliary spring 55, and plays the role of positioning the auxiliary spring 55.

At multiple locations on the outer periphery of the flange portion 48a of the valve-opening side stopper 48, flat portions 57 are provided that define fuel passages between them and the inner peripheral surface of the fixed core 14. A plurality of fuel holes 58 are provided.

As shown in FIGS. 2 and 3, the valve closing side stopper 49 is fixed to the rod 43 and is slidably fitted onto the inner circumferential surface of the large diameter magnetic cylinder 12, that is, the inner circumferential surface of the valve housing 9. will be combined. A plurality of orifice members 50 having orifices 50a communicating between the front end surface and the rear end surface of the valve closing side stopper 49 are fitted. At this time, the plurality of orifice members 50 are arranged at equal intervals along the circumferential direction of the valve-closing stopper 49.

Further, on the rear end surface of the valve-closing stopper 49, which is opposite to the flat front end surface of the movable core 41, an annular abutment part 51 is provided on the outer periphery of the valve-closing stopper 49, which protrudes in an annular shape and is concentric with the valve-closing stopper 49. , and a tapered surface 52 that continues in a dish shape is formed on the inner peripheral side thereof. The orifice member 50a is disposed inside the tapered surface 52 in the radial direction.

Next, the operation of this embodiment will be explained.

In the electromagnetic fuel injection valve I, when the coil 32 is in a non-energized state, the valve body 40 is pressed by the set load of the valve spring 54 to close the fuel injection hole 28 by seating on the valve seat 27. state. In this valve-closed state, high-pressure fuel discharged from a fuel pump (not shown) into the fuel distribution pipe 20 is supplied to the fuel supply cylinder 16 through the fuel supply cap 21, and the inside of the fuel injection valve I, that is, the fuel supply pipe 16, is The insides of the retainer 53, fixed core 14, movable core 41, valve housing 9, etc. are filled and standby.

At this time, the pulsations in the fuel pressure that occur in the fuel distribution pipe 20 due to variations in the discharge pressure of the fuel pump, etc., are attenuated by the orifice of the orifice member 24 at the inlet of the fuel supply cylinder 16, and the pulsations are transferred to the inside of the fuel injection valve I. The impact of this is eliminated or reduced.

On the other hand, as shown in FIG. 2, in such a valve closed state, the movable core 41 is held in contact with the annular contact portion 51 of the valve closing side stopper 49 by the set load of the auxiliary spring 55, and is fixed. A predetermined distance is maintained between the core 14 and the core 14.

When the coil 32 is energized in such a valve closed state, the movable core 41 is attracted to the fixed core 14 by the magnetic force generated between the fixed core 14 and the movable core 41, so first, while compressing the auxiliary spring 55, It slides upward on the rod 43 and comes into contact with the valve opening side stopper 48. That is, at the time of its initial movement, the movable core 41 approaches the fixed core 14 while quickly compressing the auxiliary spring 55, which has a smaller set load than the valve spring 54, and obtains a sudden increase in the suction force from the fixed core 14, so that the movable core 41 moves toward the valve opening side. Push up the stopper 48 vigorously.

Therefore, the movable core 41 quickly moves further upward against the large set load of the valve spring 54 while being accompanied by the valve opening side stopper 48, and is attracted to the suction surface 14a of the movable core 41.

Since the valve-opening stopper 48, which moves upward together with the movable core 41, is fixed to the rod 43 of the valve body 40, the valve portion 42 can be moved away from the valve seat 27, and the valve can be opened. When the valve body 40 opens, high-pressure fuel waiting inside the valve housing 9 or the like is directly injected from the fuel injection hole 28 into the combustion chamber 6 of the internal combustion engine E. In this way, the valve-opening response of the valve body 40 can be improved, and the power consumption of the coil 32 can be reduced.

Next, when the coil 32 is de-energized, the valve-opening side stopper 48 is pushed by the large set load of the valve spring 54, so the valve-opening side stopper 48 moves along with the movable core 41 and the valve body 40. It immediately moves to the valve seat 27 side, seats the valve portion 42 on the valve seat 27, and closes the valve to stop fuel injection from the fuel injection hole 28. This closed state of the valve body 40 is reliably maintained by a large set load of the valve spring 54.

On the other hand, the movable core 41 is forcefully pushed toward the contact position with the valve-closing stopper 49 by the set load of the auxiliary spring 55. At this time, since the set load of the auxiliary spring 55 is relatively small, a bouncing phenomenon may occur in the movable core 41 due to the impact of contact with the valve-closing stopper 49. When a bouncing phenomenon occurs in the movable core 41, a pressure difference occurs before and after the valve-closing stopper 49, which is slidably fitted to the inner circumferential surface of the valve housing 9, and accordingly, the reciprocating flow of fuel occurs in the orifice 50a. The bouncing phenomenon of the movable core 41 can be brought to an early end by suppressing the reciprocating flow caused by the damper effect of the orifice 50a. Therefore, the bouncing time of the movable core can be significantly shortened, and even if the fuel injection interval time is extremely short, as in the case of a multi-stage fuel injection valve, the bouncing phenomenon can be resolved by the time the coil 32 is energized next. It is possible to maintain predetermined fuel injection characteristics.

Furthermore, an annular contact portion 51 that can come into contact with the flat front end surface of the movable core is provided near the outer periphery of the rear end surface of the valve-closing side stopper 49, so that when the coil 32 is cut off, the movable core 41 is When the annular contact portion 51 contacts at one point in the tilted position, the one point, that is, the fulcrum, is located near the outer periphery of the valve-closing side stopper 49 that is slidably fitted to the inner peripheral surface of the valve housing. With this, the auxiliary spring 55 has a large arm length between the fulcrum and the central axis of the auxiliary spring 55, and applies a large return moment to the movable core 41, bringing the movable core 41 into contact with the entire annular contact portion 51. It is possible to immediately return to the proper posture. This also contributes to convergence of the bouncing phenomenon of the movable core 41.

Moreover, since the plurality of orifices 50a are arranged at equal intervals along the circumferential direction of the valve-closing side stopper 49, when the fuel passes through each orifice 50a, the valve-closing side stopper 49 The moment acting on the movable core 41 is balanced as a whole, and the inclination of the valve-closing side stopper 49 can be suppressed, thereby preventing the valve-closing side stopper 49 from impacting unevenly against the movable core 41, and preventing the impact caused by the unevenly touching. This can prevent the bouncing phenomenon of the valve closing side stopper 49 from increasing.

In addition, in the valve closed state in which the entire annular contact portion 51 of the valve-closing side stopper 49 is in contact with the flat front end surface of the movable core 41, the annular contact portion 51 creates a gap between the movable core 41 and the valve-closing side stopper 49. , the contact area where the fuel oil film is generated is significantly reduced. Therefore, the sticking force between the movable core 41 and the valve-closing stopper 49 due to the fuel oil film can be substantially nullified, and the valve-opening response of the valve body 40 can be improved when the coil 32 is energized.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the present invention as set forth in the claims. It is possible.

For example, the abutting portion 51 on the rear end surface of the valve-closing stopper 49 may be formed of a plurality of protrusions arranged in an annular shape along the circumferential direction of the valve-closing stopper 49. Furthermore, a vertical groove may be provided on the outer peripheral surface of the valve-closing stopper 49 as the orifice 50a.

I...Electromagnetic fuel injection valve 9...Valve housing 14...Fixed core 27...Valve seat 32...Coil 40...Valve body 41...Movable core 42... Valve part 43... Rod 48... Valve opening side stopper 49... Valve closing side stopper 50a... Orifice 51... Contact part 54... Valve spring 55... Auxiliary spring

Claims (2)

A valve housing (9) having a valve seat (27) at the front end, a hollow fixed core (14) connected to the rear end of the valve housing (9), and arranged around the outer periphery of the fixed core (14). a coil (32) provided therein, a valve body (40) in which a rod (43) is connected to a valve portion (42) that cooperates with the valve seat (27), and a valve body (40) that is arranged in the valve housing (9). a movable core (41) that is slidably fitted around the outer periphery of the rod (43) while facing the fixed core (14) and allows fuel to flow within the valve housing (9); (43), and is pushed by the movable core (41) to open the valve body (40) when the fixed core (14) is attracted to the movable core (41) by energization of the coil (32). A valve opening side stopper (48) that causes the valve to open, a valve closing side stopper (49) fixed to the rod (43) closer to the valve seat (27) than the valve opening side stopper (48), and the valve body (40) in the valve-closing direction, and a valve spring (54) that moves the movable core (41) away from the valve-opening side stopper (48) when the coil (32) is not energized to the valve-closing side. An electromagnetic fuel injection valve including an auxiliary spring (55) that urges the stopper (49) to come into contact with the stopper (49),
The valve-closing stopper (49) is slidably fitted to the inner peripheral surface of the valve housing (9), and the valve-closing stopper (49) has an orifice (50a) communicating between its front and rear end surfaces. ), and an annular bulge concentric with the valve-closing stopper (49) near the outer periphery of the rear end surface of the valve-closing stopper (49) and capable of abutting against the flat front end surface of the fixed core (14). An electromagnetic fuel injection valve characterized in that an annular contact portion (51) is provided. The electromagnetic fuel injection valve according to claim 1,
An electromagnetic fuel injection valve characterized in that the orifice (50a) is a plurality of orifices arranged at equal intervals along the circumferential direction of the valve-closing stopper (49).