JP2024070166A - Electromagnetic fuel injection valve - Google Patents

Abstract

To secure stable fuel injection characteristic by suppressing excessive overshoot of a valve element at the time of electric conduction of a coil, in an electromagnetic fuel injection valve including a valve spring and an auxiliary spring.SOLUTION: A regulation space S is provided between facing surfaces of a retainer 50 and a rod 43 of a valve element 40 at the time of closing the valve element 40. The regulation space S is set so as to be zero to suppress overshoot to a certain distance α by receiving the rod 43 with the retainer 50 when the valve element 40 overshoots exceeding a predetermined valve opening stroke v at the time of electric conduction of a coil 32.SELECTED DRAWING: Figure 2

Description

The present invention relates to an electromagnetic fuel injection valve used primarily in the fuel supply system of an internal combustion engine, and in particular to a fuel injection valve body consisting of a valve housing having a valve seat at its front end, a hollow fixed core connected to the rear end of the valve housing, and a hollow fuel inlet tube connected to the rear end of the fixed core, a coil disposed on the outer periphery of the fixed core, a valve body formed by connecting a rod to a valve section that cooperates with the valve seat, a movable core that faces the front end face of the fixed core and is slidably fitted on the inner periphery of the valve housing and the outer periphery of the rod, and a movable core that is fixed to the rod and has a coil disposed on the outer periphery of the fixed core. The invention relates to an improvement to an electromagnetic fuel injection valve that includes a valve-opening stopper that faces the rear end face of the inlet tube and is pushed by the movable core attracted to the fixed core when the coil is energized to open the valve body, a valve-closing stopper that is disposed opposite the front end face of the movable core, a retainer that is fixed to the inner peripheral surface of the fuel inlet tube, a valve spring that is compressed between the retainer and the valve body to urge the valve body in the valve-closing direction, and an auxiliary spring that urges the movable core away from the valve-opening stopper and into contact with the valve-closing stopper when the coil is not energized.

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 towards the closing stopper is set smaller than the set load of the valve spring that biases the valve body in the valve closing direction, so that when the coil is energized, as the attractive force of the fixed core against the movable core increases, the movable core quickly approaches the fixed core against the set load of the auxiliary spring, and the rapidly increasing attractive force of the fixed core causes the movable core to be attracted to the fixed core while immediately pushing up the opening stopper against the set load of the valve spring, quickly opening the valve body. This has the advantage of improving the valve opening responsiveness of the valve body and reducing the power consumption of the coil.

However, in such conventional electromagnetic fuel injection valves, when the coil is energized, the suction force of the fixed core increases rapidly, causing the moving core to be attracted to the fixed core while pushing up the valve-opening stopper. As a result, the valve-opening stopper and the valve body integrated with it experience an overshoot c-e, a phenomenon in which they operate far beyond the specified valve-opening stroke v due to their inertia, as shown in Figure 4. Since there is then an overshoot due to the reaction, the overshoot convergence time t1 becomes quite long, which may cause distortions in the fuel injection characteristics.

The present invention was made in consideration of these circumstances, and aims to provide an electromagnetic fuel injection valve that can ensure stable fuel injection characteristics by suppressing excessive overshooting of the valve opening stopper and valve body when the coil is energized.

In order to achieve the above object, the present invention provides a fuel injection valve body comprising 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 fuel inlet tube connected to the rear end of the fixed core; a coil disposed on the outer periphery of the fixed core; a valve body formed by connecting a rod to a valve section that cooperates with the valve seat; a movable core that faces the front end face of the fixed core and is slidably fitted on the inner periphery of the valve housing and the outer periphery of the rod; a valve opening stopper that is fixed to the rod and faces the rear end face of the movable core, and that is pushed by the movable core attracted to the fixed core when the coil is energized to open the valve body; and a valve opening stopper that is disposed opposite the front end face of the movable core. In an electromagnetic fuel injection valve having a valve-closing stopper that is fixed to the inner peripheral surface of the fuel inlet tube, a valve spring that is compressed between the retainer and the valve body and urges the valve body in the valve-closing direction, and an auxiliary spring that urges the movable core away from the valve-opening stopper and into contact with the valve-closing stopper when the coil is not energized, a regulating gap is provided between the opposing surfaces of the retainer and the rod when the valve body is closed, and the regulating gap is set to zero when the coil is energized and the valve body overshoots beyond a specified valve-opening stroke so that the retainer receives the rod and suppresses the overshoot to a certain distance.

In addition to the first feature, the present invention has a second feature in that the retainer is composed of a retainer body fixed to the inner peripheral surface of the fuel inlet tube, a flange that is arranged to abut against the front end of the retainer body, and a spring receiver having a hollow cylindrical shaft that protrudes from the front end surface of the flange, the regulating gap is set between the opposing surfaces of the cylindrical shaft and the rod, and the valve spring is compressed between the flange and the valve body while surrounding the cylindrical shaft.

Furthermore, in addition to the second feature, the third feature of the present invention is that the rear end surface of the rod is formed into a convex curved surface concentric with the rod, and the regulating gap is set between the convex curved surface and the inner peripheral edge of the cylindrical shaft. The convex curved surface corresponds to the convex spherical surface 43a in the embodiment of the present invention described below.

Furthermore, in addition to the second feature, the fourth feature of the present invention is that a through hole is provided in the side wall of the cylindrical shaft, connecting the inside and outside of the shaft.

According to the first feature of the present invention, when the coil is energized, the suction force of the fixed core increases rapidly, causing the movable core to push up the valve-opening stopper while being attracted to the fixed core. In the process, the rod of the valve body closes the regulating gap set between it and the retainer, and when the overshoot of the valve body reaches a certain distance after the movable core is attracted to the fixed core, the rod abuts against the retainer, thereby preventing the valve body from overshooting excessively beyond the certain distance. As a result, overshoot due to reaction is also kept to a minimum, the convergence time of the overshoot is significantly shortened, and the fuel injection characteristics can be stabilized.

According to the second feature of the present invention, the retainer is composed of a retainer body fixed to the inner peripheral surface of the fuel inlet tube, a flange arranged to abut against the front end of the retainer body, and a spring bearing having a hollow cylindrical shaft protruding from the front end surface of the flange, and the regulated gap is set between the cylindrical shaft and the rod, so that the retainer body can easily set the regulated gap by adjusting its fixed position on the inner surface of the fuel inlet tube, and in the spring bearing, the valve spring is compressed between the flange and the valve body while surrounding the cylindrical shaft, so that the expansion and contraction posture of the valve spring can be stabilized and the closing load of the valve spring on the valve body can be appropriately maintained.

According to the third feature of the present invention, the rear end surface of the rod is formed into a convex curved surface concentric with the rod, and a regulating gap is set between this convex curved surface and the inner peripheral edge of the cylindrical shaft. In order to prevent the valve body from overshooting, when the convex curved surface of the rod abuts against the inner peripheral edge of the cylindrical shaft, a centering action is performed at the abutting portion, and the valve body can be prevented from tilting.

According to the fourth feature of the present invention, when the valve body opens, a portion of the fuel that flows from inside the retainer body into the cylindrical shaft is diverted to the outer periphery of the cylindrical shaft through the through hole, which prevents an increase in flow resistance inside the injection valve body due to the cylindrical shaft and ensures an appropriate amount of fuel injection.

1 is a vertical sectional view of an electromagnetic fuel injection valve for an internal combustion engine according to an embodiment of the present invention; 2 is an enlarged cross-sectional view of the fuel injection valve in a closed state; FIG. FIG. 3 is a view corresponding to FIG. 2 and illustrating an open state of the fuel injection valve. The behavior characteristic diagram of the movable core and the valve body shows a comparison between the present invention and the prior art.

An embodiment of the present invention will be described with reference to the attached Figures 1 to 3.

First, in Figures 1 and 2, a mounting hole 7 that opens into a combustion chamber 6 is provided in a cylinder head 5 of an internal combustion engine E, and an electromagnetic fuel injection valve I of the present invention capable of injecting fuel toward the combustion chamber 6 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, and the opposite side is the rear.

The valve housing 9 of this electromagnetic fuel injection valve I is composed of a hollow cylindrical housing body 10, a valve seat member 11 fitted and welded to the inner circumference of the front end of the housing body 10, a magnetic cylinder 12 whose front end is fitted and welded to the outer circumference of the rear end of the housing body 10, and a non-magnetic cylinder 13 whose front end is coaxially connected to the rear end of the magnetic cylinder 12. The rear end of the non-magnetic cylinder 13 is coaxially connected to the front end of a cylindrical fixed core 14 having a hollow portion 15a, and the rear end of the fixed core 14 is integrally and coaxially connected to a fuel inlet tube 16 having a hollow portion 15b slightly smaller in diameter than the hollow portion 15a. Thus, the valve housing 9, fixed core 14, and fuel inlet tube 16 constitute the fuel injection valve main body Ia.

The magnetic cylinder 12 has a flange-shaped yoke portion 12a integral with it at its axial middle, and a cushioning material 18 is placed between the cylinder head 5 and the yoke portion 12a and is housed in an annular groove 17 provided in the cylinder head 5 so as to surround the outer end of the mounting hole 7.

An orifice member 24 and a fuel filter 19 located downstream of the orifice member 24 are attached to the inlet of the fuel inlet tube 16. A fuel supply cap 21 that branches off from a fuel distribution pipe 20 that is connected to the discharge port of a fuel pump (not shown) is fitted to the fuel inlet tube 16 via an annular seal member 22. A bracket 23 is attached to the top of the fuel supply cap 21, and this bracket 23 is detachably fastened to the cylinder head 5 by an appropriate fixing means (e.g., a bolt) to a support (not shown) that is erected on the cylinder head 5.

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

The valve seat member 11 is formed in a cylindrical shape with a bottom, with an end wall portion 11a at its front end, and a conical valve seat 27 is formed on the end wall portion 11a, with a plurality of fuel nozzle holes 28 opening near the center of the valve seat 27. This valve seat member 11 is fitted and welded to the front end portion of the housing body 10 so that the fuel nozzle holes 28 open toward the combustion chamber 6. In other words, the valve housing 9 is configured to have the valve seat 27 at its front end portion.

A coil assembly 30 is fitted to the outer peripheral surface of the magnetic cylinder 12 from the rear end to the fixed core 14. This coil assembly 30 is composed of a bobbin 31 that fits onto the outer peripheral surface and a coil 32 that is wound around this bobbin 31, and the front end of a magnetic coil housing 33 that surrounds this coil assembly 30 is connected to 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 to connect to the rear end of the coil housing 33, and a coupler 34a that holds a terminal 35 connected to the coil 32 is formed integrally with this coating layer 34 so that it protrudes to one side of the electromagnetic fuel injection valve I.

The rear end of the non-magnetic cylinder 13 is fitted into the small diameter front end of the fixed core 14 so that its outer circumferential surface is connected to the fixed core 14, and then welded liquid-tightly.

A part of the valve body 40 and the movable core 41 are housed in the valve housing 9 extending from the valve seat member 11 to the non-magnetic cylinder 13. The valve body 40 is composed of a valve portion 42 that cooperates with the valve seat 27 to open and close the fuel nozzle hole 28, and a rod 43 that extends into the fixed core 14. The valve portion 42 is formed spherically so as to slide within the valve seat member 11, and the rod 43 is formed with 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 the outer circumferential surface of the valve portion 42 is formed with a plurality of flat portions 45 that define a fuel passage between the valve seat member 11 and the valve portion 42. The valve seat member 11 therefore allows the passage of fuel while guiding the opening and closing operation of the valve body 40.

The movable core 41 is fitted slidably and rotatably between the inner peripheral surface of the valve housing 9 and the outer peripheral surface of the rod 43, with its rear end surface (attracted surface) 41a facing the front end surface (attracted surface) 14a of the fixed core 14. Therefore, a sliding gap 56a is provided between the outer peripheral surface of the movable core 41 and the inner peripheral surface of the valve housing 9, and a sliding gap 56b is provided between the inner peripheral surface of the movable core 41 and the outer peripheral surface of the rod 43. The movable core 41 is also disposed straddling the magnetic cylinder 12 and the non-magnetic cylinder 13.

In order to regulate the sliding stroke of the movable core 41 on the rod 43 at a constant value, an opening valve side stopper 48 and a closing valve side stopper 49, which are arranged on either side of the movable core 41, are fixed to the rod 43 by welding. At this time, the opening valve side stopper 48 faces the rear end face 41a of the movable core 41 that faces the fixed core 14 so as to be able to abut against it, and the closing valve side stopper 49 is positioned so as to face the front end face of the movable core 41 so as to be able to abut against it.

When the valve body 40 is in the closed state (see FIG. 2), the movable core 41 abuts against the closing side stopper 49 and faces the opening side stopper 48 with a gap g corresponding to the sliding stroke between them, and this gap g, i.e., the sliding stroke g, is set smaller than the gap m between the movable core 41 in abutment against the closing side stopper 49 and the fixed core 14, i.e., the movable stroke m of the movable core 41. Therefore, when the fixed core 14 attracts the movable core 41 as the coil 32 is energized, the movable core 41 first abuts against the opening side stopper 48 and is then attracted to the fixed core 14.

The opening stopper 48 is composed of a flange portion 48a that slidably fits onto the inner peripheral surface of the fixed core 14, and a cylindrical shaft portion 48b that protrudes from the flange portion 48a toward the movable core 41. The flange portion 48a is fixed to the rod 43 by welding, and is positioned so that a part of the shaft portion 48b protrudes toward the movable core 41 beyond the suction surface 14a when the valve body 40 is in the closed position.

1 and 2, a retainer 50 is disposed in the hollow portion 15b of the fuel inlet tube 16. This retainer 50 is composed of two members, a retainer body 51 and a spring bearing 52. The retainer body 51 is a cylindrical body with a slit 51a and elasticity in the radial direction, and is press-fitted into the inner peripheral surface of the fuel inlet tube 16 and then crimped to fix it. The spring bearing 52 is composed of a flange 52a that is disposed in contact with the front end of the retainer body 51 and a hollow cylindrical shaft 52b that protrudes from the front end surface of the flange 52a. The valve spring 54 is compressed between the flange 52a and the valve-opening stopper 48 while surrounding the cylindrical shaft 52b of the spring bearing 52, and biases the valve body 40 in the valve-closing direction. The side wall of the cylindrical shaft 52b is provided with one, or preferably multiple (two in the illustrated example) through holes 53 that communicate between the inside and outside of the cylindrical shaft 52b.

A regulating gap S is set between the opposing surfaces of the cylindrical shaft 52b and the rod 43. This regulating gap S is set to a distance that is equal to a small fixed distance α plus the valve opening stroke v of the valve body 40 until the movable core 41 is attracted to the fixed core 14 while pushing up the valve opening stopper 48 when the coil 32 is energized. Therefore, when the valve body 40 overshoots beyond the valve opening stroke v after the movable core 41 is attracted to the fixed core 14 by energizing the coil 32, the cylindrical shaft 52b receives the rod 43 so as to suppress the overshoot to the fixed distance α, and this regulating gap S becomes zero.

The rear end surface of the rod 43 is formed into a convex spherical surface 43a that is concentric with the rod 43, and the above-mentioned restriction gap S is set between this convex spherical surface 43a and the inner peripheral edge of the cylindrical shaft 52b.

Ideally, the constant distance α would be set to zero to completely prevent overshooting of the valve body 40, but doing so would make it difficult to maintain the opening stroke v of the valve body 40 at the specified value due to machining errors in each part. Therefore, the constant distance α is set as small as possible while taking machining errors and other factors into account, within the range in which the specified opening stroke v of the valve body 40 can be ensured.

Auxiliary spring 55 is compressed and disposed between flange portion 48a of opening side stopper 48 and movable core 41, surrounding shaft portion 48b of opening side stopper 48. A set load smaller than the set load of valve spring 54 is applied to this auxiliary spring 55, and biases movable core 41 away from opening side stopper 48 and toward closing side stopper 49.

The rear end of the rod 43 protrudes beyond the flange portion 48a of the valve-opening stopper 48 and fits into the inner peripheral surface of the movable end of the valve spring 54, thus fulfilling its positioning function. The shaft portion 48b of the valve-opening stopper 48 also fits into the inner peripheral surface of the auxiliary spring 55, thus fulfilling its positioning function.

The flange portion 48a of the opening stopper 48 has flat portions 57 at multiple locations on its outer periphery that define a fuel passage between the flange portion 48a and the inner periphery of the fixed core 14, and the movable core 41 has multiple fuel holes 58 arranged in an annular pattern.

Next, we will explain the operation of this embodiment.

In the electromagnetic fuel injection valve I, when the coil 32 is not energized, the valve body 40 is pressed by the set load of the valve spring 54, and is seated on the valve seat 27 to close the fuel nozzle hole 28, resulting in a closed valve state. Meanwhile, the movable core 41 is held in an abutting position against the valve-closing stopper 49 by the set load of the auxiliary spring 55, and faces the fixed core 14 with a gap m between them. In addition, the rod 43 of the valve body 40 faces the cylindrical axis 52b of the retainer 50 with a regulating gap S between them.

In this closed valve state, high-pressure fuel discharged from a fuel pump (not shown) to a fuel distribution pipe 20 is supplied to the fuel inlet tube 16 through the fuel supply cap 21, filling the inside of the fuel injection valve body Ia, i.e., the inside of the fuel inlet tube 16, the pipe-shaped retainer 50, the fixed core 14, the movable core 41, the valve housing 9, etc., and waiting.

At that time, the pulsation of the fuel pressure that occurs in the fuel distribution pipe 20 due to fluctuations in the discharge pressure of the fuel pump, etc., is damped by the orifice of the orifice member 24 at the inlet of the fuel inlet tube 16, eliminating or reducing the effect on the inside of the fuel injection valve I.

When current is applied to the coil 32 in this valve-closed state, the magnetic force generated between the fixed core 14 and the movable core 41 causes the movable core 41 to be attracted to the fixed core 14, so that it first compresses the auxiliary spring 55 and slides upward on the rod 43 in FIG. 2 until it comes into contact with the valve-opening stopper 48 (see FIG. 4, a to b). That is, when the movable core 41 first moves, it approaches the fixed core 14 while quickly compressing the auxiliary spring 55, which has a smaller set load than the valve spring 54, and receives a sudden increase in the attractive force from the fixed core 14, thrusting the valve-opening stopper 48 up with force.

As a result, as shown in FIG. 3, the movable core 41, accompanied by the valve-opening stopper 48, quickly moves further backward against the large set load of the valve spring 54 and is attracted to the movable core 41 (see b-c in FIG. 4).

The valve-opening stopper 48, which moves rearward together with the movable core 41, is integrated with the rod 43 of the valve body 40, so that the valve body 40 can move a specified valve-opening stroke v to lift the valve portion 42 off the valve seat 27 and open the valve (see b-c in FIG. 4). When the valve body 40 opens, high-pressure fuel waiting inside the valve housing 9 etc. is directly injected from the fuel nozzle 28 into the combustion chamber 6 of the internal combustion engine E. In this way, the valve-opening responsiveness of the valve body 40 is improved and the power consumption of the coil 32 can be reduced.

However, when the movable core 41 pushes up the opening stopper 48, the opening stopper 48, together with the rod 43, i.e., the valve body 40, may move beyond the specified opening stroke v of the valve body 40 due to inertia, i.e., an overshoot may occur.

When such overshoot reaches a certain distance α, the rod 43 is received by the cylindrical shaft 52b with the regulating gap S reduced to zero, as shown by the dotted line in Figure 3, and as shown in c to d in Figure 4. This makes it possible to suppress the overshoot of the valve body 40 to a certain distance α, which is much smaller than the conventional overshoot, as shown in c to e in Figure 4. As a result, it is possible to minimize the overshoot caused by the reaction, and to suppress the convergence time of the overshoot to t2, which is much shorter than the conventional t1, as shown in Figure 4, which can contribute to stabilizing the fuel injection characteristics.

The retainer 50 is composed of a retainer body 51 that is press-fitted and crimped to the inner circumferential surface of the fuel inlet tube 16, a flange 52a that is placed in contact with the front end of the retainer body 51, and a spring receiver 52 that has a hollow cylindrical shaft 52b that protrudes from the front end surface of the flange 52a. Since the regulated gap S is set between the cylindrical shaft 52b and the rod 43, the retainer body 51 can easily set the regulated gap S by adjusting the press-fit position of the retainer body 51 to the inner circumferential surface of the fuel inlet tube 16. In addition, in the spring receiver 52, the valve spring 54 is compressed between the flange 52a and the valve-opening side stopper 48 that is integral with the valve body 40 while surrounding the cylindrical shaft 52b, so that the expansion and contraction posture of the valve spring 54 can be stabilized and the valve closing load of the valve spring 54 on the valve body 40 can be properly exerted.

Furthermore, the rear end surface of the rod 43 is formed into a convex spherical surface 43a that is concentric with the rod 43, and a regulating gap S is set between this convex spherical surface 43a and the inner peripheral edge of the cylindrical shaft 52b. Therefore, when the convex spherical surface 43a of the rod 43 abuts against the inner peripheral edge of the cylindrical shaft 52b, a centering action is performed at the abutting portion to prevent the valve body 40 from tilting and ensure the proper valve opening position in order to suppress overshooting of the valve body 40.

In addition, a through hole 53 that connects the inside and outside of the cylindrical shaft 52b is provided in the side wall of the cylindrical shaft 52b, so that a portion of the fuel that flows from inside the retainer body 51 into the cylindrical shaft 52b is diverted to the outer periphery of the cylindrical shaft 52b through the through hole 53, which prevents the cylindrical shaft 52b from increasing the flow resistance in the fuel injection valve body Ia and ensures an appropriate amount of fuel injection.

Next, when the current to the coil 32 is cut off, the valve opening stopper 48 is pushed by the large set load of the valve spring 54, so that the valve opening stopper 48 immediately moves toward the valve seat 27 together with the movable core 41 and the valve body 40, seating the valve portion 42 on the valve seat 27, closing the valve and stopping fuel injection from the fuel nozzle 28. The valve body 40 is reliably maintained in the closed state by the large set load of the valve spring 54.

Meanwhile, the movable core 41 is pressed by the set load of the auxiliary spring 55 and supported by the closing side stopper 49.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various design changes can be made without departing from the present invention described in the claims. For example, the valve-closing stopper 49 can be fitted and fixed to the inner peripheral surface of the valve housing 9 instead of being fixed to the rod 43.

I. . . Electromagnetic fuel injection valve Ia. . . Fuel injection valve body g. . . Moving stroke of the movable core between the closing side stopper and the opening side stopper m. . . Total moving stroke of the movable core v. . . Opening stroke S of the valve body. . . Regulating gap α. . . Fixed distance 9. . . Valve housing 14. . . Fixed core 16. . . Fuel inlet tube 27. . . Valve seat 32. . . Coil 40. . . Valve body 41. . . Moving core 42. . . Valve portion 43. . . Rod 43a. . . Convex curved surface (convex spherical surface)
48: valve opening stopper 49: valve closing stopper 50: retainer 51: retainer body 52: spring receiver 52a: flange 52b: cylindrical shaft 53: through hole 54: valve spring 55: auxiliary spring

Claims (4)

The fuel injection valve body (Ia) is composed of a valve housing (9) having a valve seat (27) at a front end, a hollow fixed core (14) connected to the rear end of the valve housing (9), and a hollow fuel inlet tube (16) connected to the rear end of the fixed core (14); a coil (32) disposed on the outer periphery of the fixed core (14); a valve body (40) formed by connecting a rod (43) to a valve portion (42) cooperating with the valve seat (27); a movable core (41) facing the front end face of the fixed core (14) and slidably fitted on the inner periphery of the valve housing (9) and the outer periphery of the rod (43); a valve-opening side stopper (48) that is pushed by the movable core (41) attracted to the fixed core (14) to open the valve body (40) when the coil (32) is energized, a valve-closing side stopper (49) that is disposed opposite to a front end face of the movable core (41), a retainer (50) that is fixed to an inner peripheral surface of the fuel inlet tube (16), a valve spring (54) that is compressed between the retainer (50) and the valve body (40) to urge the valve body (40) in a valve-closing direction, and an auxiliary spring (55) that urges the movable core (41) away from the valve-opening side stopper (48) and into contact with the valve-closing side stopper (49) when the coil (32) is not energized,
an electromagnetic fuel injection valve, characterized in that when the valve body (40) is closed, a regulating gap (S) is provided between opposing surfaces of the retainer (50) and the rod (43), and the regulating gap (S) is set so that when the valve body (40) overshoots beyond a specified valve opening stroke (v) when the coil (32) is energized, the retainer (50) receives the rod (43) and restricts the overshoot to a constant distance (α). The electromagnetic fuel injection valve according to claim 1, characterized in that the retainer (50) is composed of a retainer body (51) fixed to the inner peripheral surface of the fuel inlet tube (16), a flange (52a) arranged to abut against the front end of the retainer body (51), and a spring receiver (52) having a hollow cylindrical shaft (52b) protruding from the front end surface of the flange (52a), the regulating gap (S) is set between the opposing surfaces of the cylindrical shaft (52b) and the rod (43), and the valve spring (54) is compressed between the flange (52a) and the valve body (40) while surrounding the cylindrical shaft (52b). The electromagnetic fuel injection valve according to claim 2, characterized in that the rear end surface of the rod (43) is formed into a convex curved surface (43a) concentric with the rod (43), and the regulating gap (S) is set between the convex curved surface (43a) and the inner peripheral edge of the cylindrical shaft (52b). The electromagnetic fuel injection valve according to claim 2, characterized in that a through hole (53) that connects the inside and outside of the cylindrical shaft (52b) is provided in the side wall of the cylindrical shaft (52b).