JP6763634B2 - Fuel injector - Google Patents

Description

The present invention relates to a fuel injector for use when feeding high pressure fuel to an internal combustion engine.

Both indirect and direct action injectors are known for use in fuel injection systems. In the indirect action injector, the control valve device can operate to control the fuel pressure in the control chamber, and this fuel pressure acts on the upper end of the injection valve needle. The pressure level in the control chamber determines the balance of forces on the needle and thus controls the exact timing of needle movement to initiate injection away from the seating surface of the valve needle. Actuators, such as electromagnetic actuators, control the control valve device. The force applied by the actuator is not directly related to the movement of the valve needle, but controls the control valve device, which in turn controls the resulting force applied to the valve needle via the hydraulic circuit.

In a direct action injector, the actuator is directly connected to the valve needle and controls the movement of the needle. Both piezoelectric and electromagnetic direct action injectors are known. In an electromagnetic direct action injector, an electromagnetic actuator controls the movement of a plunger having a plunger diameter by passing an electric current through the solenoid. The plunger acts on a fuel chamber located at the upper end of the valve needle, which is the second diameter of the smaller diameter. The device acts as a hydraulic amplifier, using which the force of the plunger is transmitted to the valve needle with an amplification factor determined by the ratio of the plunger diameter to the diameter of the valve needle. As the plunger is actuated and pulled upwards, the volume of the chamber increases and the fuel pressure in the control chamber is reduced, thus reducing the force that tends to act to seat the valve needle. When the working force is removed by removing or reducing the current flowing through the solenoid, the plunger receives a spring force and moves downward, reducing the volume of the control chamber and increasing the fuel pressure in the control chamber. To seat the valve needle.

What is desirable is to provide an injector that can withstand high forces. This allows the needle to retract more quickly with greater force, allowing the system to adapt to more complex injection progressions, allowing the use of high pressure fuels, and being used within the injection system. Reduce the restrictions on possible components. However, the amount of force that can be applied using a conventional direct action fuel injector is limited by the geometry of the fuel injector. In particular, the opening force applied to the needle is countered by the resistance force, and these resistance values increase as the diameter of the plunger increases. What this means is that, in practice, the diameter of the plunger cannot exceed the maximum threshold, primarily about 8 mm. As a result, the maximum force that can be applied to the needle is mainly about 110N.

An object of the present invention is to provide an injector that addresses the drawbacks of the prior art.

Against this background, the present invention belongs to fuel injectors for use in internal combustion engines. The fuel injector has a needle shaft and is reciprocally reciprocating in a hole in the nozzle housing along the needle shaft toward and away from the needle seat, a force transducer and It comprises a needle actuator with a force transducer and. The force applyer is configured to apply a radial force to the force transducer in the direction across the needle shaft. The force transducer is configured to convert the radial force into a longitudinal force that is substantially parallel to the needle axis. The needle actuator is configured to apply a longitudinal force to the needle, which causes the needle to move along the needle axis.

In this way, the present invention provides a fuel injector, in which the movement of the needle is controlled by applying a radial force by an applyer, which radial force is controlled by a force converter. Converted to longitudinal force. Therefore, the needle can be referred to as a "side actuated type". This lateral actuation is advantageous as it allows the force transducer to be placed around the outside of the needle rather than at one end of the needle, which requires the actuator to occupy space in the longitudinal direction. Means not.

The force transducer may include at least one rotating member configured to rotate around a rotation point to convert a radial force into a longitudinal force. The use of the rotating member in this way provides a particularly simple means of converting a radial force into a longitudinal force. Further, the force applied to the needle can be finely adjusted by selecting the dimensions of the rotating member and the position of rotation, so that the actuator according to the present invention is required in various applications. It is possible to configure it so as to apply a force.

At least one rotating member may include a first lever portion on the adapter side of the rotating point and a second lever portion on the needle side of the rotating point. The force applyer may be configured to apply a radial force to the first lever portion, the rotating member in a direction that rotates around the rotation point and has a component substantially parallel to the needle shaft of the second lever portion. Can be configured to move with.

At least one rotating member may include a lever arm having an elbow body that acts as a rotation point. By rotating the elbow body in this way, a particularly small configuration of the rotating member becomes possible.

The force transducer may include a plurality of rotating members. The rotating member may have a flow path between the rotating members. Each rotating member may at least partially define a segment of a substantially cylindrical outer shell. This arrangement is particularly effective as the cylindrical outer shell allows the force transducer to be fitted snugly into the hole while allowing the flow path to flow through and around the rotating member. It is advantageous, and as a result of using a plurality of rotating members, the force applied to the needle is averaged to promote smooth operation of the fuel injector.

The housing may define the shoulder, and the rotating member is positioned such that the rotation point abuts and supports the shoulder during rotation of the rotating member. The shoulders provide a particularly stable means of fixing the position of the force transducer within the holes in the housing.

The rotating member may include a rotating region in the vicinity of the rotating point, which may be formed of a material that is mechanically harder than the material of the rest of the rotating member. Forming the rotating region with a material that is harder than the rest of the rotating member means that the rotating region is particularly wear resistant, which improves the life of the fuel injector.

The force applyer may have an electromagnetic coil. In this case, the portion of the force transducer adjacent to the coil may be formed of a magnetic material, and the electromagnetic coil may be configured to cause a radial force applied to the force change by operating the electromagnetic coil. The combination of the electromagnetic coil and the lateral actuation described above is particularly advantageous compared to conventional axial actuation, as the degaussing of the system occurs faster when the system is magnetized radially rather than axially. This allows greater control over the delivery of fuel into the combustion chamber.

Similarly, other operating means for applying a radial force are assumed.

The force transducer may include a head portion that applies a longitudinal force to the needle. The head portion can be connected to the needle via a first braking means such as a lash adjuster (HLA). Braking means can provide braking means and also function to position the head portion. The head portion may be sandwiched between first and second braking means such as first and second HLA.

The fuel injector may include a return means configured to exert a return force to deflect the needle toward the needle seat. The return means may include a needle spring and / or a push-up flange.

The fuel injector may include a needle guide for guiding the movement of the needle within the hole. In embodiments with a push-up flange, the push-up flange can function as a needle guide.

The actuators described above can be used in conjunction with hydraulic amplifiers. In this case, the needle includes a plunger portion and a needle portion. The force transducer is configured to apply a longitudinal force to the plunger portion, which is connected to the needle portion via a hydraulic amplification system, whereby the longitudinal movement of the plunger portion is , Causes the movement of the needle portion along the needle shaft.

What is expressly intended within the scope of the present application is the various aspects, forms, examples, and alternative examples described in the claims and / or in the following description and drawings in the paragraph above, in particular these. The individual features can be taken independently or in any combination. That is, all forms and / or features of any form can be combined in any way and / or combination as long as such features do not conflict.

In order to understand the present invention more quickly, examples of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 5 is a schematic cross-sectional view showing a fuel injector in a closed position according to an embodiment of the present invention, wherein the fuel injector has a valve needle actuated by an actuator. A partial cross-sectional view taken along lines AA showing the fuel injector in the closed position of FIG. 1 showing the relative positions of the injector components when the injector is in the closed position. It is a figure. It is an enlarged partial sectional view which shows a part of the fuel injector of FIG. FIG. 3 is a schematic cross-sectional view showing the fuel injector of FIG. 1 in the “open” position, in which fuel can flow from a plurality of outlets to the combustion chamber at this open position. FIG. 4 is a partial cross-sectional view taken along line BB showing the fuel injector in the open position of FIG. 4, showing the relative positions of the injector components when the injector is in the open position. It is a figure. FIG. 5 is a schematic cross-sectional view showing a fuel injector according to another embodiment in the closed position of the present invention. FIG. 5 is a schematic cross-sectional view showing a fuel injector according to another second embodiment in a closed position of the present invention. FIG. 5 is a schematic cross-sectional view showing a fuel injector according to another third embodiment in a closed position of the present invention. FIG. 5 is a schematic cross-sectional view showing a fuel injector according to another fourth embodiment in a closed position of the present invention.

For the purposes of the following discussion, what is known is that references to, for example, upper, lower, upper, lower, upper, lower, etc. are not intended to be limiting, only to the orientation of the injector as shown. It is limited and related.

The present invention relates to the type of fuel injector 10 shown as a whole in FIG. The injector 10 is a direct acting fuel injector suitable for use in a fuel injection system of an internal combustion engine, particularly a diesel engine, in which the fuel mainly exceeds 2000 bar. It is injected into the engine at a high pressure level, which is generally as high as 3000 bar.

The injector 10 has an injection nozzle 12 at the lower end of the injector, and the lower end has a valve needle 14. The valve needle 14 defines a longitudinal needle shaft L, and the needle 14 is slidable in the blind hole 16 provided in the injection nozzle housing 18 under the action of the actuator 20, and this actuator. Similarly forms part of the injector 10. The fuel receiving high pressure is fed to the inner injector volume 22 defined in the hole 16 through the high pressure supply flow path (not shown). The valve needle 14 can engage with the valve needle seat 22 defined by the blind end 24 of the hole 16 and controls the flow of fuel from the injector 10 to the combustion chamber of the engine (not shown).

The injection nozzle housing 18 has an upper injection nozzle housing 26 and a lower injection nozzle housing 28. The lower injection nozzle housing 28, the upper injection nozzle housing 26, and the actuator 20 are housed in the cap nut 30 and firmly hold these parts at predetermined positions with respect to each other.

Considering the actuator 20 in more detail, the actuator 20 includes a force applyer 32 and a force transducer 34. The force applyer 32 is configured to apply a radial force to the force transducer 43 in a direction crossing the needle shaft L, and the force transducer 34 applies a radial force in the longitudinal direction substantially parallel to the needle shaft L. It is configured to convert to force. The force transducer 34 is configured to apply a longitudinal force to the needle 14, which causes the needle 14 to be moved along the needle shaft L so as to be separated from the valve seat 22.

As can be best seen in FIG. 3, the force transducer 34 has a plurality of rotating members 36, and these rotating members rotate around the rotation point 38 to apply a radial force to a longitudinal force. It is configured to convert to. Each of the rotating members 36 is defined by a lever arm body 40, which lever arm body has first and second lever portions 42 and 44 connected by an elbow body 46. When in use, the elbow body 46 functions as a rotation point 38. The first lever portion 42 is substantially disposed on the adapter side of the rotation points 38, and the second lever portion 44 is substantially disposed on the needle side of the rotation points 38. The rotation point 38 is arranged in contact with the shoulder portion 48 defined by the housing 18.

As best seen in FIG. 2, the rotating member 36 surrounds the needle 14, whereby the plurality of rotating members 36 both have a substantially cylindrical outer shell that is coaxial with the valve needle 14. Draw. In this way, each of the rotating members 36 is at least partially defined by a segment of a substantially cylindrical outer shell. The rotating member 36 has a flow path between the rotating members, allowing oil to pass between the segments of the force transducer 34 and around the segments.

With reference to FIG. 3 again, the first and second lever portions 42 and 44 are substantially parallel to each other. At one end of the first lever portion 42 that is separated from the needle seat 22, a movement stop portion 50 is formed on the first lever portion 42, and this movement stop portion abuts on the needle 14 during use. The rotational movement of the rotating member 36 is restricted. At one end of the second lever portion 44 closest to the valve needle 14, the second lever portion 44 is provided with a head portion 52, and this head portion exerts a longitudinal force on the needle 14 during use. multiply.

At least a part of the first lever portion 42 of the force transducer 34 is made of a magnetic material. In particular, the portion of the force transducer 34 adjacent to the force applyer 32 is made of a magnetic material such as FeSi or FeCo. The force transducer 34 may be similarly coated with a non-magnetic material.

The rotating member 36 includes a rotating region 54 arranged in the vicinity of the elbow body 46 or the rotating point 38. In this rotating region 54, the rotating member 36 comprises a material that is mechanically harder than the material of the rest of the rotating member 36. For example, the rotating region 54 can be formed of carbon or stainless steel, or another material with suitable high mechanical hardness.

The rotating member 36 of the force transducer 34 can be formed by a suitable method, for example by metal powder injection molding or by sintering. Multiple regions that can integrate different materials into the rotating member during the manufacturing process and have various properties (eg, a magnetic region near the force applyer, or a material with high mechanical hardness in the rotating region). To form. Further or / or various regions of the rotating member may be treated differently after molding or sintering, such as by heat treating a particular region.

The force applyer 32 has an electromagnetic coil 56. The electromagnetic coil 56 surrounds the force transducer 34 and the needle 14, whereby the coil 56, the force transducer 34 and the needle 14 are coaxial with each other. During use, the current can flow through the coil 56, inducing a magnetic field within the housing, which attracts the magnetic material of the force transducer 34.

The force applyer 32 is housed in a recess 58 defined between the upper injection nozzle housing 26 and the lower injection nozzle housing 28. The non-magnetic annular spacer 60 is provided in the coil 56 between the coil 56 and the inner injector volume 24. During operation, the spacer 60 separates the coil 56 from the high pressure oil, ensuring that the coil 56 remains dry.

Here, when the valve needle 14 is turned back to FIG. 1 and referred to, the valve needle 14 has a lower tip region 62 closest to the valve seat 22 and a top region 64 at the end away from the valve seat 22. It has an intermediate region 66 between the top region 64 and the tip region 62. The tip region 62 has a relatively small diameter and is seated to the valve needle seat 22 when the valve is closed. The top region 64 of the valve needle is attached to the inner surface of the housing by a needle spring 67.

The intermediate region 66 has a larger diameter than the lower tip region 62. Moving from the bottom of the intermediate region 66 as shown in FIG. 1, the intermediate region 66 is surrounded by a needle guide 68 in the form of a ring, which is attached to the housing 18. A through-passage 70 is formed in the needle guide body 68, and this through-passage allows oil to pass through the ring. In this way, the needle guide body 68 functions to guide the needle 14 without disturbing the flow of oil in the hole 16.

Continuing upward, the needle 14 is provided with a push-up flange 72. The push-up flange 72 comprises an annular collar body 74 fixed to the valve needle 14 and a flange section 76 at the lower edge of the collar body 74, the flange section being radially separated from the collar body 74. It extends toward the injection nozzle housing 18. The flange section 76 is configured to define a minimum gap with the injection nozzle housing 18, and the flange section defines at least a flow path for high pressure fuel flowing through the injector 10. One through-passage 78 is formed. The gangway 78 is configured to have some resistance to fuel flowing through the flange 76.

The flange 76 forms a pressure seat 80, and the high pressure oil acts on this pressure seat to direct the flange 76, and thus the needle 14 attached to the flange 76, towards the needle seat 22 as detailed below. Bounce. The flange 76 also provides a guiding function for the valve needle 14 to keep the valve needle aligned with the valve needle seat 22.

Continuing the needle 14 further upward, the needle 14 is provided with an upper collar body 82, which is located between the rotating members 36 of the force transducer 34.

As best shown in FIG. 3, the first braking means 84 in the form of the first lash adjuster (HLA) 86 is provided on the upper collar body 82 via a push-in fit. The HLA 86 is an annular HLA piston 88 composed of a collar body 90 and an inner flange 92 extending from the collar body 82 toward the needle 14, and an HLA located between the inner flange 92 of the HLA piston 88 and the upper collar body 82. It has a spring 94 and. At the time of use, the gap between the inner flange 92 of the HLA piston 88 and the upper collar body 82 is filled with oil. The valve needle 14 passes through the center of the piston 88 and spring 94 of the HLA86. The inner diameter of the inner flange 92 is slightly larger than the diameter of the valve needle 14, which allows the needle 14 to freely slide through the inner flange 92.

The second braking means 96 in the form of the second lash adjuster (HLA) 98 is provided on the collar body 74 of the push-up flange 72. The second HLA98 has almost the same configuration as the first HLA86, and has an annular HLA piston 100 including a collar body 102 and an inner flange 104 extending from the collar body 102 toward the needle 14, an inner flange 104 of the HLA piston 100, and a push-up. It has an HLA spring 106 located between the flange 72 and the collar body 102. At the time of use, the gap between the inner flange 104 of the HLA piston 100 and the collar body 102 is filled with oil.

The first and second HLA 86 and 98 are positioned so that the head portion 52 of the rotating member 36 is sandwiched between the first and second HLA 86 and 98. The first and second HLA springs 94 and 106 are in a compressed state, thereby sandwiching the rotating member. The spring force generated by the spring 94 of the first HLA 83 is slightly greater than the spring force generated by the spring 106 of the second HLA 98, so that the HLA 86, 98 urge the rotating member toward the shoulder 48. It is configured to maintain contact between the rotation region 54 and the rotation point 38. In this way, the HLAs 86 and 98 function to brake the movement of the head portion 52, as well as to urge the head portion 52 into place. However, the spring force applied by the HLA is lower than the spring force provided by the needle spring 67.

The operation of the fuel injector 10 will be described with reference to FIGS. 1 to 5. 1, 2 and 3 show the fuel injector 10 when the valve needle 14 is in the closed position. When the needle 14 is in the closed position, the force transducer 34 takes a closed configuration. 3 and 4 show the fuel injector 10 when the valve needle 14 is in the open position. When the needle 14 is in the open position, the force transducer 34 takes an open configuration.

The movement of the valve needle 14 between the closed position and the open position during the operation of the injector 10 is controlled by the current flowing through the coil 56 of the actuator 20.

With reference to FIGS. 1, 2 and 3, when the valve needle 14 is in the closed position, there is no current flowing through the coil 56 of the actuator 20, and therefore no magnetic force is applied to the force transducer 34.

The pressurized fuel in the hole 16 exerts a force on the surfaces of the needle 14, HLA86, 98 and the push-up flange 72. The pressure acts uniformly on all of these exposed surfaces. However, when the needle 14 is seated with respect to the valve seat 22, the tip region 62 is not exposed to pressurized fuel in the closed configuration, so that when the needle is closed, the tip region 62 of the needle 14 is exposed. , No power is applied. Therefore, a net downward force acts on the needle 14 to urge the needle downward toward the valve seat 22. Further, the needle spring 67 functions to further urge the needle 14 downward toward the valve seat 22. Therefore, in the closed configuration, the needle 14 is seated on the valve seat 22 under the influence of the fuel pressure on the needle surface and the force applied by the needle spring 67. Therefore, the pressure of the spring 67 reduces the possibility of leaking from the injector 10 into the combustion chamber during the non-operating period.

The first HLA 86 attached to the needle 14 via the upper collar body 82 is similarly urged downward by the action of fuel pressure on the push-up flange 72. The first HLA 86 acts on the head portion 52 of the rotating member 36 to urge the head portion downward, and the head portion urges the rotating member 36 to the closed configuration.

In the closed configuration, the head portion 52 is located approximately below the needle seat 22. The first lever portion 42 is tilted substantially inward and toward the needle shaft L. Inward tilting is restricted by the movement stop 50 that abuts the needle 14. By tilting the first lever portion 42 inward, as best shown in FIG. 2, a fuel filling gap 110 between the rotating member 36 and the upper injection nozzle housing 26 is defined.

A current is passed through the coil 56 to move the needle 14 from the closed position to the open position. When an electric current is passed, an electromagnetic field is induced in both the upper injection nozzle housing 26 and the lower injection nozzle housing 28, and this electromagnetic field attracts the magnetic portion of the rotating member 36 toward the coil in the radial direction. Therefore, by inducing a magnetic field using the coil 56, a force is applied to the rotating member 36 in the substantially radial direction, that is, in the direction crossing the needle shaft L. In particular, the coil 56 induces a force applied to the first lever portion 42 of the rotating member 36.

Due to the applied radial magnetic force, the first lever portion 42 is moved radially outward toward the housing 18. By moving the first lever portion 42 radially outward in this way, the rotating member 36 is rotated around the rotation point 38, whereby the rotation point 38 is the lower injection nozzle housing. The shoulder portion 48 of 28 is abutted and supported. The rotational movement causes the second lever portion 44, and thus the head portion 52, to move upward in the longitudinal direction, at least by a moving component along the needle shaft L.

The upward movement of the head portion 52 raises the first HLA 86 in the direction along the needle shaft L, and in turn exerts a force on the upper collar body 82. As a result, the needle 14 is pushed upward by the first HLA 86 against the pressure applied to the pressure seat 80 by the force of the needle spring 67 and the fuel so as to separate the needle 14 from the needle seat 22 in the direction along the needle shaft L. Displace to. By compressing the second HLA spring 106 in its stationary position, the second HLA 98 is brought into contact with the head portion 52 over the movement from the closed position to the open position.

Once the valve needle 14 has risen away from the valve needle seat 22, fuel can flow out into the combustion chamber through the injector and the needle 14 is now in the open position, as shown in FIGS. 4 and 5. It is in.

At the open positions of FIGS. 4 and 5, the rotating member 36 is arranged in an open configuration. In the open configuration, the first lever portion 42 is urged outward so that the first lever portion 42 is positioned in contact with the inner surface defined by the hole 16. The head portion 52 is displaced upward and is located at a position separated from the needle seat 22 with respect to the open configuration. The oil can easily flow in the flow path defined between the segments of the rotating member 36.

When it is necessary to end the injection, the current flowing through the coil 56 is removed. By removing the electric current, the magnetic force applied to the first lever portion 42 of the rotating member 36 in the radial direction is removed. As a result, the force causing the upward displacement of the second lever portion 44 is eliminated, and therefore the force causing the upward displacement of the head portion 52 is eliminated.

Therefore, the force applied from the first HlA86 to the needle 14 is removed by stopping the current. The fuel pressure acting on the pressure seat 80 of the push-up flange 72 combines the force from the needle spring 67 with the upward force acting on the propulsion surface of the valve needle 14 when there is no upward force applied to the needle by the actuator 20. The needle 14 is moved downward and to the closed position.

The first HLA 86 attached to the needle 14 via the upper collar body 82 is similarly moved downward as the needle 14 moves downward. The first HLA 86 acts on the head portion 52 of the rotating member 36 and pushes the head portion 52 downward, thereby moving the rotating member 36 to the closed configuration as shown in FIGS. 1 to 3.

Therefore, by controlling the current flowing through the coil 56, the injection can be controlled in order to accurately feed a single or multiple fuel injections. Particularly advantageous, the degaussing of the system is faster when the magnetic field is radial than when the magnetic field is axial, as the force converter 34 isolates the eddy currents. Accordingly, the radial actuator according to the present invention provides faster degaussing and thus faster closing of the valve, allowing for better control over the delivery of fuel to the combustion chamber.

Due to the configuration of the force transducer 34, the longitudinal displacement of the needle 14 is equal to the radial displacement of the first lever portion 42 of the rotating member 36. Therefore, the displacement in the longitudinal direction can be accurately controlled by controlling the dimensions of the rotating member 36.

Further, the force applied to the needle 14 via the force transducer 34 can be precisely adjusted by controlling the dimensions of the transducer 34. The principle of leverage can be applied to the first and second lever portions, and the relative dimensions of the first and second lever portions 42 and 44 can be changed to increase or decrease the applied force. For example, the length of the first lever portion 42 can be increased. This increases the distance from the rotation point 38 where the radial force is applied. Further, by increasing the length of the first lever portion 42, the volume to which the magnetic force is applied is increased, thereby increasing the overall radial magnetic force. In particular, by improving the geometric shape of the rotating member 36 by using the principle of leverage, a force exceeding 200 N can be easily realized.

The non-magnetic layer on the outer surface of the rotating member 36 protects the rotating member 36 from being magnetically attached to and separated from the housing 18 when it is completely open outward. Further, the contact between the rotating region of the rotating member 36 and the housing 28 means that the rotating member 36 is connected to a magnetic circuit, which increases the applied force and is faster. Assists in magnetic switching.

Higher climbing forces on the needle mean that the fuel injector can be used at higher fuel pressures.

The first and second HLAs 86 and 98 are provided to account for the expansion of the components under heat and high pressure received during operation. Both the HLA 86 and 98 similarly hold the head portion 52 in close proximity to the valve needle 14 during movement. Another function of the second HLA98 is to brake the movement of the rotating member 36. The speed at which the valve needle 14 is seated can cause the rotating member 36 to vibrate undesirably around the rotating shoulder 48, leading to unwanted wear. In high performance systems that require multiple injection patterns, the connection between the valve needle 14 and the rotating member 36 must not be degraded by wear and the second HLA98 brakes the system accurately, thereby. Minimize wear.

In poorly performing systems, the stress on the system and the speed of component movement are reduced. FIG. 6 shows a fuel injector 112 particularly suitable for use in such a low performance system according to a second embodiment of the present invention. The embodiment of FIG. 6 is the same as the embodiment of FIGS. 1 to 5 except that the second HLA 98 is omitted. In this second embodiment, the head portion 52 of the rotating member 36 abuts and supports the first HLA86. In this way, the first HLA 86 still functions to urge the head portion 52 into place and to brake the movement of the head portion 52 during the transition from the closed configuration to the open configuration. The second HLA 98 may be omitted because in a low performance system the injector 112 can respond more quickly without the braking effect of the second HLA 98. Therefore, the embodiment of FIG. 6 is a simpler fuel injector that is easier to manufacture and maintain.

FIG. 7 shows a fuel injector 114 according to a third embodiment of the present invention. In the embodiment of FIG. 7, the push-up flange 174 is incorporated into the top region 64 of the valve needle 14 to form a pressure seat 80, and high pressure oil acts on the pressure seat to move the needle 14 to the valve seat. It is the same as the embodiment of FIGS. 1 to 5 except that it is urged toward. The push-up flange 174 also provides a guiding function for the valve needle 14 and keeps the valve needle aligned with the valve needle seat 22. In this way, the area of the pressure seat 80 acted on by the oil is increased, the downward acting force provided is greater, and the needle 14 is urged towards the needle seat 22 or displaced during operation. Let me. Higher forces allow for more complex injection patterns, resulting in higher performance injectors.

Although the present invention has been described for a direct action fuel injector with a single needle, it is understood that there are a number of different systems in relation to the actuators according to the embodiments detailed with respect to FIGS. Can be combined. Accordingly, FIG. 8 shows a fuel injector 116 according to a fourth embodiment of the present invention, wherein the fuel injector utilizes a combination of mechanical and hydraulic amplification methods to provide the present invention. use. In this embodiment, the needle 14 includes a plunger portion 118 and a needle portion 120, and the force transducer 34 is configured to apply a longitudinal force to the plunger portion 118 along the needle shaft L. The plunger portion 118 is connected to the needle portion 120 via a hydraulic pressure amplification system 122, so that the longitudinal movement of the plunger portion 118 causes the needle portion 120 to move along the needle shaft L.

In conventional indirect injectors, a combination of mechanical and hydraulic amplification systems is known. However, the reliability of these systems for axial actuators with low upward force to provide results in the need for high amplification factors. In particular, such conventional systems require amplification factors between 3 and 4. By using radial actuation according to the present invention, a high initial force can be achieved for the plunger, thereby achieving the same output, primarily with a smaller amplification factor between 1.05 and 2. A small amplification factor is particularly advantageous as it allows for greater design freedom of the component and also allows the design of smaller components that are less sensitive to hydraulic waves.

FIG. 9 shows the fuel injector 124 according to the fifth embodiment of the present invention. In the embodiment of FIG. 9, the force applyer 32 includes an annular magnetic sleeve 126 in the present embodiment, except that the magnetic sleeve further enhances the performance of the fuel injector 124. It is the same as the embodiment of. The sleeve 126 is integrated with the upper injection nozzle housing 26, whereby the sleeve surrounds at least a portion of the magnetic region of the rotating member 36. At least some sleeves 126 are made from magnetic materials such as FeSi or FeCo, whereby the sleeves 126 increase the radial magnetic force applied to the rotating member 36 during injection.

Although the force transducer is provided with four rotating arms in the embodiments illustrated and described, any suitable number of rotating arms may be used. In the above-described embodiment, the movement stop portion is provided on each of the rotating arm bodies to limit the rotation of the rotating member. However, an embodiment in which a rotation stop portion is provided on the needle, such as a collar body surrounding the needle, and the rotating member abuts on the collar body to limit the rotation of the rotating member. Is assumed.

Appropriate components of the injection system can be combined with each other as needed. For example, the collar member or push-up flange can be integrated with the valve needle. The second HLA can be integrated with the push-up flange, if desired.

Other modifications and modifications will be apparent to those skilled in the art without departing from the appended claims.

10 Fuel injector, 14 valve needle, 16 holes, 18 nozzle housing, 20 needle actuator, 22 needle seat, 32 force applyer, 34 force converter, 36 rotating member, 38 rotating point, 42 1st lever Part, 44 2nd lever part, 46 elbow body, 48 shoulder part, 56 electromagnetic coil, 64 rotation area, 67 return means, needle spring, 68 needle guide body, 72 return means, needle guide body, push-up flange, 84 1st Braking means, 96 second braking means, 118 plunger part, 120 needle part, 122 hydraulic amplification system, L needle shaft

Claims (15)

A fuel injector (10) for use in an internal combustion engine.
A valve needle having a needle shaft (L) and reciprocating in the nozzle housing (18) along the needle shaft (L) toward the needle seat (22) and away from the needle seat. (14) and
A needle actuator (20) including a force adapter (32) and a force transducer (34),
With
The force applyer (32) is configured to apply a radial force to the force transducer (34) in a direction crossing the needle shaft (L).
The force transducer (34) is configured to convert the radial force into a longitudinal force substantially parallel to the needle shaft (L).
The needle actuator (20) is configured to apply the longitudinal force to the valve needle (14), thereby causing the valve needle (14) to move along the needle shaft (L). ,
The force applyer (32) has an electromagnetic coil (56) that surrounds the force converter (34) and the valve needle (14), whereby the electromagnetic coil (56) and the force converter (34). ) And the valve needle (14) are coaxial with each other. The force transducer (34) comprises at least one rotating member (36) configured to rotate around a rotation point (38) to convert the radial force into the longitudinal force. The fuel injector according to claim 1. At least one of the rotating members (36) is located on the first lever portion (42) on the force applying device side of the rotating point (38) and on the valve needle side of the rotating point (38). With a second lever part (44)
The force applyer (32) is configured to apply the radial force to the first lever portion (42).
The rotating member (36) is configured to rotate around the rotation point (38), and the second lever portion (44) is moved in a direction having a component substantially parallel to the needle shaft. The fuel injector according to claim 2. The second or third claim, wherein at least one rotating member (36) includes a lever arm body (40) having an elbow body (46) that functions as the rotating point (38). Fuel injector. The force transducer (34) includes a plurality of the rotating members (36), and the rotating member has a flow path between the rotating members.
The fuel injector according to any one of claims 2 to 4, wherein each of the rotating members (36) is at least partially defined by a segment of a substantially cylinder-shaped outer shell. .. The nozzle housing (18) defines the shoulder portion (48).
The rotating member (36) is characterized in that the rotating point (38) is positioned so as to abut and support the shoulder portion (48) during the rotation of the rotating member (36). The fuel injector according to any one of claims 2 to 5. The rotating member (36) includes a rotating region (54) in the vicinity of the rotating point (38).
The fuel according to any one of claims 2 to 6, wherein the rotating region (54) is made of a material that is mechanically harder than the material of the remaining portion of the rotating member. Injector. The force applyer (32) includes an electromagnetic coil (56).
The portion of the force transducer (34) adjacent to the electromagnetic coil (56) is made of a magnetic material.
Claims 1 to 7 are characterized in that the electromagnetic coil (56) is configured to cause the radial force applied to the force converter (34) by operating the electromagnetic coil (56). The fuel injector according to any one of the above items. The force transducer (34) comprises a head portion (52) that applies the longitudinal force to the valve needle (14).
The fuel injector according to any one of claims 1 to 8, wherein the head portion (52) is connected to the valve needle (14) via a first braking means (84). .. The fuel injector according to claim 9, wherein the head portion (52) is sandwiched between the first braking means (84) and the second braking means (96). The valve needle (14) is further provided with returning means (67, 72) configured to deflect the valve needle (14) toward the needle seat (22) by applying a returning force. The fuel injector according to any one of claims 1 to 10. The fuel injector according to claim 11, wherein the return means includes a push-up flange (72). The invention according to any one of claims 1 to 12, further comprising a needle guide body (68, 72) for guiding the movement of the valve needle (14) in the hole (16). Fuel injector. The fuel injector according to claim 13, wherein the push-up flange (72) functions as the needle guide body. The valve needle (14) includes a plunger portion (118) and a needle portion (120).
The force transducer (34) is configured to apply the longitudinal force to the plunger portion (118).
The plunger portion (118) is connected to the needle portion (120) via a hydraulic pressure amplification system (122), whereby the longitudinal movement of the plunger portion (118) is caused by the needle shaft (128). The fuel injector according to any one of claims 1 to 14, wherein the needle portion (120) is moved along the L).

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