JPH041462A - Valve element structure in fuel injection valve - Google Patents

Abstract

PURPOSE:To reduce a flow velocity of fuel as far as, for example, to half and also the minimum fuel injection quantity to half, by way of example, as well as to increase the extent of resolution for a fuel injection quantity by installing an on-off valve, capable of jetting, for example, a half amount of the fuel injec tion quantity at time of fully opening, in the inner part of a valve element, and opening or closing this on-off valve at discretion. CONSTITUTION:A valve element 41 provides a valve part 41a and a valve element side fuel injection nozzle 41e at a tip of a valve body 41d. In addition, a valve element internal valve 41f opening or closing this valve element side fuel injection nozzle 41e is installed. Moreover, the tip side of a cylindrical piezoelectric element 41l is caulked and clamped to the base end side of the valve element internal valve 41f. An on-off valve, opening or closing the valve element side fuel injection nozzle 41e, is constituted of the piezoelectric element 41l and the valve element internal valve 41f driven by the former. With this constitution, the on-off valve capable of jetting, for example, as far as a half amount of the fuel injection quantity is installed in the inner part of the valve element.

Description

[Detailed description of the invention] [Purpose of the invention]

(Industrial Application Field) The present invention relates to a fuel injection valve used to supply fuel to an engine, and particularly relates to a valve body structure of the fuel injection valve. (Prior Art) An example of a conventional fuel injection valve used to supply fuel to an engine is one having a structure as shown in FIG. 5 (described in Utility Model Application No. 1-85463). There is. In the fuel injection valve 1 shown in FIG. 5, reference numeral 2 indicates a fuel injection valve body formed in a stepped cylindrical shape, and 3 indicates a stepped cylindrical fuel injection nozzle provided at the tip of the fuel injection valve body 2. show,
A fuel injection port 3b having a valve seat 3a is formed on the inner periphery of the tip side of the fuel injection nozzle 3, and a valve portion 4a of a valve body 4, which will be described later, is configured to collect dust on this valve seat 3a. . Further, at the base end (upper end in the figure) of the fuel injection nozzle 3, a stopper 5 formed of a substantially U-shaped or C-shaped plate is located between it and the lower end of the stepped portion 2a of the fuel injection valve body 2. The stopper 5 is provided to restrict the valve opening position of the valve body 4. The valve body 4 functions as a valve movable in the axial direction within the fuel injection nozzle 3, and the base end side of the valve body 4 extends into the stepped portion 2a of the fuel injection valve body 2. The anchor 9 is displaceable integrally with the anchor 9, which will be described later.
It has an anchor fixing part 4b fixed to. The distal end side of the valve body 4 extends inside the injection nozzle 3 with a fuel passage 6 secured between it and the fuel injection nozzle 3,
The valve portion 4a at the tip is adapted to open and close the fuel injection port 3b by depositing dust on the valve seat 3a. Further, a circumferential protrusion 4C is formed in the axially intermediate portion of the valve body 4,
This protrusion 4C comes into contact with the stopper 5 when the valve body 4 is opened, thereby regulating the valve opening position. Further, reference numeral 11 indicates a cylindrical core member provided extending in the axial direction within the fuel injection valve main body 2, and this core member 11 is formed into a stepped cylindrical shape from a magnetic material such as electromagnetic stainless steel. A protrusion 11a located on the end side and protruding upward in the figure from the fuel injection valve body 2, and a protrusion 11a located on the axially intermediate portion to close the base end side of the fuel injection valve body 2. 2, and a core portion 11d that extends downward in the figure from the flange portion 11b and has an enlarged diameter hole 11c formed on the inner periphery of the distal end thereof. It is configured. A coil pobbin 13, around which an electromagnetic coil 12 is wound, is provided on the outer periphery of the core portion 11d, and is positioned between the fuel injection valve body 2 and the anchor 9 to attract the anchor 9 upward in the figure. 4 constitutes an electromagnetic actuator that opens the valve. Furthermore, as described above, reference numeral 9 is an anchor located between the core member 11 and the valve body 4 and movably disposed within the fuel injection valve main body 2. This anchor 9 is similar to the core member 11. It is formed from a magnetic material into a closed cylinder shape, and its tip (
Lower end side) An anchor fixing part 4b on the proximal end side of the valve body 4 is located on the inner periphery.
It is fixed using means such as caulking. The proximal end surface of the anchor 9 faces the distal end surface of the core portion 11d with a gap 10 of a predetermined size in between, and is attracted upward in the figure by the magnetic force from the core portion 11d. Further, a small gap 15 is formed on the outer peripheral side of the anchor 9 between the coil pobbin 3 and the stepped portion 2a of the fuel injection valve main body 2, and fuel from a fuel pipe 16 (described later) passes through the gap 15. The fuel flows into the fuel passage 6. Further, reference numeral 16 indicates a fuel pipe that is axially inserted and fixed in the core member 11, and 17 indicates a valve spring disposed between the tip of the fuel pipe 16 and the end surface of the anchor 9. The spring 17 presses the anchor 9 downward in the figure, thereby always urging the valve body 4 in the valve closing direction. The spring load of the valve spring 17 is then applied to the fuel pipe 1.
6, this fuel pipe 16 is spring loaded II! ! ! It is then fixed to the core member 11 by caulking or other means. Furthermore, 21 indicates a fuel hose connected to the protrusion 11a of the core member 11, and this fuel water hose 21 supplies fuel pumped from a fuel pump (not shown) into the fuel pipe 16 etc. through a filter 22. It is supposed to be done. Furthermore, 23 is located on the base end side of the fuel injection valve main body 2, and q
It shows a connector integrated into a part of the outer periphery of the second part 1M,
This connector 23 inputs a fuel injection pulse 24 from the outside to the electromagnetic coil 12 as shown in FIG.
Magnetic force is generated on the tip side of 1d. The conventional fuel injection valve 1 has the above-mentioned configuration,
Fuel from the fuel pump is supplied through the fuel hose 21 and fuel vibe 1
6 etc., into the fuel injection valve main body z at a predetermined fuel pressure, and passes through the gap 15 between the anchor catalytic converter, the coil pobbin 13, and the stepped portion 2a of the fuel injection valve main body 2 into the fuel passage 6. reach Then, the injection pulse 24 from the outside
When power is supplied to the electromagnetic coil 12 via the connector 23, the core member 11 is excited, and the anchor 2 is attracted to the distal end side of the core portion 11d against the expansion force of the valve spring 17, and the valve body 4 is The valve part 4a is separated from the square seat 3a and opened, and fuel is injected outward from the fuel injection port 3b of the fuel injection nozzle 6. When the power supply is stopped, the valve spring 17 presses the anchor, and the valve portion 4 of the valve body 4 is pressed.
a is seated on the valve seat 3a and stops fuel injection. (Problem N to be solved by the invention) By the way, in the conventional fuel injection yP1 described above, the valve portion 4a of the valve body 4 is moved away from the valve seat 3a using an electromagnetic actuator. Since the electromagnetic coil 12 that constitutes the actuator has a time constant,
As shown in FIG. 6, the core member 11 cannot be energized to the Jg seat when the toit injection pulse 24 is input, and since the valve body 4 is in close contact with the valve seat 3a when the valve is closed, the core member 11 is not energized. However, there is a problem in that the valve body 4 cannot be opened immediately. Therefore, in the conventional fuel injection valve 1, the valve body 4 repeatedly opens and closes with the valve opening characteristic curve 25 illustrated in FIG. There was a problem that a valve opening delay occurred for a time T, resulting in poor responsiveness when opening the valve. By the way, the fuel injection amount of this type of fuel injection valve 1 is controlled by adjusting the opening and closing time of the valve body 4 of the fuel injection valve 1 during boat fishing. ~800 rpm) to full throttle (7
Since the wide range from 000 to 8000 rpm is adjusted only by the opening time of the fuel injector 1 (the fuel flow rate is not adjusted), it is not possible to accurately control the small amount of fuel injection during idle rotation, etc. ■There were problems such as the inability to increase the resolution of fuel injection amount control (precise control of the air/fuel ratio), and the challenge was to resolve these problems. (Object of the Invention) The present invention has been made in view of the above-mentioned problems in the prior art, and includes an on-off valve that is capable of injecting, for example, half the amount of fuel injected when the valve is fully open. The on-off valve is provided internally, and the on-off valve is closed in a range from idling to when the fuel injection amount can be reduced to, for example, half of the fully open amount, and is closed in the range from full open where a larger amount of fuel injection is required than the on-off valve. By opening the fuel injector, the maximum fuel injection amount can be halved, for example, and by reducing the fuel flow velocity by half, the minimum fuel injection amount at idle rotation can also be halved, reducing the fuel injection amount. The object of the present invention is to provide a valve body structure for a fuel II4 injection valve that can also improve the resolution of the fuel injection valve.

[Structure of the Invention] Means for Solving Problem 1) A valve body structure of a fuel injection valve according to the present invention includes a fuel injection valve main body, a fuel injection port provided at a tip of the fuel injection valve main body, The fuel injection valve includes a valve body that opens and closes the fuel injection port, and an electromagnetic actuator that is provided inside the fuel injection valve body and opens and closes the valve body in response to input of a fuel injection pulse. Inside, a valve body-side fuel injection port provided at the tip of the valve body, a valve body internal valve for opening and closing the valve body side fuel injection port, and a valve body internal valve provided inside the valve body for inputting fuel injection pulses. The present invention is characterized by having an on-off valve equipped with a piezoelectric element that opens and closes the internal valve of the valve body according to the above-described configuration, and solves the above-mentioned conventional problems with the configuration of the valve body structure of such a fuel injection valve. It is used as a means to do so. Further, in one embodiment of the valve body structure of the fuel injection valve according to the present invention, the valve body internal valve provided inside the # marked valve body has a fuel injection amount that is half of the maximum fuel injection amount, and the fuel injection valve has a fuel injection amount that is half of the maximum fuel injection amount. The valve body of the valve can be configured to be capable of injecting a fuel injection amount up to half of the minimum fuel injection amount and the maximum fuel injection amount by changing the fuel injection time. (Operation of the Invention) The valve body structure of a fuel injection valve according to the present invention has the above-mentioned configuration, and has a fuel injection valve containing, for example, half the amount of fuel injected when the valve is fully opened, inside the valve body of the fuel injection valve. The on-off valve is provided with an on-off valve that can inject fuel, and the on-off valve is closed when the fuel injection amount can be reduced to, for example, half of the full-open amount from idling, and when the fuel injection amount is full-open, which requires a larger amount of fuel than this. In the above range, by opening the on-off valve, the maximum fuel injection amount of the fuel injection valve is reduced to, for example, about half, and by reducing the fuel flow velocity to, for example, half, the minimum fuel injection amount during idle rotation is also reduced to, for example, about half. This brings about the effect that the resolution of the fuel injection amount is also improved. (Embodiment) FIG. 1 shows a valve body structure of a fuel injection valve according to an embodiment of the present invention, and the valve body 41 according to the present invention is similar to the fuel injection valve shown in FIG. It is provided inside the fuel injection nozzle 3 of the valve 1, and the valve part 41a at the tip of the valve body 41 is connected to the valve seat 3a provided at the lower end of the fuel injection nozzle 3.
When the vehicle is separated from the vehicle, fuel is ejected from the fuel injection port 3b provided in the fuel injection nozzle 3. In addition, a circumferential raised member 41c is provided in the middle of the valve body 41, similar to that shown in FIG. Regulations are now in place. The valve body 41 shown in FIGS. 1 and 2 according to the present invention used in the fuel injection valve 1 shown in FIG.
The hollow valve body 41d has the above-mentioned valve part +ta at the tip thereof, and has a valve body side fuel injection port 41e, and the valve body side fuel injection port 41e is provided inside the hollow valve body 41d.
A valve body internal valve 41f that opens and closes is provided, and a seal ring 41g is provided between the valve body internal valve 41f and the valve body 41d, and a valve portion 41h at the tip of the valve body internal valve 41f is connected to the valve body 41f. It is designed to be seated and separated from a valve seat 41i that is continuous with the fuel injection port 416 on the valve body side. This valve body internal valve 41f is guided by a valve guide 41j, and a seal ring 41k is provided between the valve guide 41j and the valve body 41d. The tip side of the cylindrical piezoelectric element 41 is caulked and fixed. Further, the distal end side of the valve body 41m having the circumferential protrusion 41c is press-fitted and fixed to the proximal end side of the hollow valve body 41d via a seal ring 41n, and the distal end of the valve body 41m The side and the cylindrical piezoelectric element 41 are caulked and fixed, and the valve body side fuel injection 041e is opened and closed by the piezoelectric element 41 and the valve body internal valve 41f driven by the piezoelectric element 41. It constitutes an on-off valve. Further, in the side wall portion of the hollow valve body 41d, a fuel passage 41p is provided on the lower side of the valve guide 41J, and a fuel drain passage 41q is provided on the upper side. A fuel injection valve 1 equipped with a valve body 41 having such a structure
When a voltage is applied between the inner circumferential side and the outer circumferential side of a cylindrical piezoelectric element 4141 via a lead wire (not shown), this piezoelectric element 41 has a characteristic of contracting in its axial direction, Since the piezoelectric element 41 is in an extended state when no voltage is applied, the valve portion 4 of the valve body internal valve 41f
1h, the valve body side fuel injection port 41e is closed and no fuel is injected. In this state, the piezoelectric element 41! When a voltage is applied to l, the cylindrical piezoelectric element 412 contracts in its axial direction, so the on-off valve provided inside the valve body 41 is in the on state (open state), and the fuel After passing through the passage 41P, the fuel passes through the gap between the valve portion 41h of the valve body internal valve 41f and the valve seat 41t, and is injected from the valve body side fuel injection port 41e. FIG. 3 illustrates the relationship between the valve opening time of the fuel injection valve 1 and the fuel injection amount when the on-off valve is opened and closed (on-off time), and the horizontal axis of this 1g3 diagram is the fuel injection valve. The vertical axis shows the fuel injection amount, and the solid line shows the fuel injection amount of the invention example, and the broken line shows the fuel injection amount of the conventional example for comparison. As shown in FIG. 3, in this example, the slope of the solid line is about half of the slope of the broken line, so the error in the fuel injection amount due to the error in the valve opening time is also about half, and the fuel injection amount The precision of control is improved. Furthermore, since the flow velocity is approximately halved, the minimum fuel injection amount is also approximately halved, and the fuel injection amount during idle rotation is also reduced, improving fuel efficiency and purifying exhaust gas. Furthermore, in the valve structure of this embodiment, the valve body 41 shown in FIG. 1 can be applied as is in place of the conventional valve body 4 shown in FIG. Components other than the valve body 4 can be used as they are. Furthermore, since the cylindrical piezoelectric element 41f is used as a driving means for the internal valve 41f, if the power supply circuit fails, it will be used in an area where the amount of fuel injection is small. It is extremely safe for Figure $4 shows another embodiment of the 9F structure of the fuel injection valve according to the present invention, in which the tip is in contact with the internal valve 41f of the valve body, and the base end is located inside the cylindrical pressure plate 41. A case is shown in which a spring 41r is provided which comes into contact with the valve body 41m, and the valve body internal valve 41 is pressed by the spring 41r in a direction to close the valve a side fuel injection port 41e. With such a structure, if the piezoelectric element 41
Even when the valve is damaged, the valve body internal valve 411 always closes the fuel injection port 1e on the valve body side, so it is used in an area where the amount of fuel to be injected is small, making it safer for the vehicle to run. Become. Effects of the Invention The valve body structure of a fuel injection valve according to the present invention includes a fuel injection valve main body, a fuel injection port provided at the tip of the fuel injection valve main body, and a valve body that opens and closes the fuel injection port. and a fuel injection valve equipped with an electromagnetic actuator that is provided inside the fuel injection body 5F and opens and closes the 11+1 body in response to input of a fuel injection pulse; a valve body-side fuel injection port provided in the part; and a valve body internal valve that opens and closes the Ff4t-prepared fuel injection port;
Since the configuration includes an on-off valve provided inside the valve body and equipped with a piezoelectric element that opens and closes the internal valve of the valve body in response to input of a fuel injection pulse, the amount of fuel injected at 8g is reduced to, for example, half of the amount of fuel injected at 8 g. By providing an on-off valve inside the valve body that can inject an amount of fuel, the on-off valve is closed and the fuel is The maximum fuel injection 1 of the injection valve can be halved, for example, and the fuel flow rate can be halved, so the minimum fuel injection amount can be halved, for example. In the region, by opening the on-off valve, the maximum fuel injection amount of the fuel injector can be halved, for example, and the fuel flow rate can be reduced, for example, by half.
It is possible to increase the resolution of the fuel injection amount, resulting in significantly superior effects such as improvement in fuel efficiency and purification of exhaust gas.

[Brief explanation of drawings]

1 is an explanatory cross-sectional view showing one embodiment of the valve body structure of a fuel injection valve according to the present invention; FIG. 2 is an explanatory cross-sectional view showing a structure in which the valve body of FIG. 1 is provided in a fuel injection valve; The figure is a graph illustrating the relationship between the opening time of the fuel injection valve and the fuel injection amount when the on-off valve provided inside the valve body is on and off, together with a conventional example. T! 8
8 is a cross-sectional explanatory diagram showing another example of the valve body structure of the rice valve, FIG. 5 is a cross-sectional explanatory diagram showing the structure of the fuel injection valve, and FIG. FIG. 3 is an explanatory diagram showing valve characteristics depending on fuel injection pulses. 1...Fuel injection valve, 2...Fuel injection valve body, 3b.
...Fuel injection port, 12... Magnetic coil (% magnetic actuator), 17... Valve spring (electromagnetic 7 actuator) 41... Valve body, 41e... Valve body side fuel injection port, 41f ...Valve inside the valve body (on-off valve) 41 sentences... Piezoelectric element (on-off valve)

Claims (1)

[Claims] (1) A fuel injection valve main body, a fuel injection port provided at the tip of the fuel injection valve main body, a valve body for opening and closing the fuel injection port, and a fuel injection port provided inside the fuel injection valve main body. In a fuel injection valve equipped with an electromagnetic actuator that opens and closes the valve body in response to input of a pulse, a valve body-side fuel injection port provided at the tip of the valve body is provided inside the valve body, and a valve body-side fuel injection port is provided inside the valve body, and the valve body side fuel It is characterized by having an internal valve for opening and closing the injection port, and an on-off valve that is provided inside the valve body and includes a piezoelectric element that opens and closes the internal valve for the valve body in response to input of a fuel injection pulse. Fuel injection valve.