JP2019056374A - Injector for reductant delivery unit having fluid volume reduction assembly - Google Patents

Abstract

To reduce damage caused by an urea water solution at a temperate that is a freezing point or lower in a fluid injector for a non-purge SCR system.SOLUTION: A fluid injector 12 includes: a fluid inlet; a fluid outlet; a fluid path from the fluid inlet to the fluid outlet; a tube 42; a filter 204 disposed in the tube proximal to the fluid inlet; and a calibration filter tube 402 disposed downstream of the filter. The calibration filter tube includes a first end portion 402B adjacent to the filter and an axial through-bore 402A. The through-bore defines a portion of the fluid path through the fluid injector, and has a diameter smaller than the inner diameter of the tube. Thus, since this structure reduces a volume of a reductant passing through the injector, problems caused by the reductant frozen in the fluid path can be reduced.SELECTED DRAWING: Figure 12

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is filed in U.S. Patent Application No. (Attorney Docket No. 2017P03658US) entitled "Injector for Reducing Agent Supply Unit with Reduced Fluid Volume". US Patent Application No. (Attorney Docket No. 2017P03660US) entitled “Seal Member for Reductant Supply Unit”, filed in US, and “Reductant Supply Unit with Fluid Volume Reduction Assembly” Related to US Patent Application No. (Attorney Docket No. 2017P03659US) entitled “Injector for Use”. The contents of the above applications are incorporated herein by reference in their entirety.

TECHNICAL FIELD The present invention relates generally to reducing agent supply unit (RDU) fluid injectors, and more particularly to a robust RDU fluid injector for non-purge applications.

Emissions regulations in Europe and North America are particularly for lean combustion technologies such as compression ignition (diesel) engines and stratified combustion spark ignition engines that operate under lean and ultra lean conditions (usually direct injection) , Promoting the realization of a new exhaust aftertreatment system. Lean burn engine generates high levels of nitrogen oxides (NO _X) emissions, the NO _X emissions are difficult to handle in the lean combustion of the oxygen rich exhaust environment. Exhaust aftertreatment technologies for processing NO _X under these conditions are currently being developed.

One of these technologies includes a catalyst that promotes the reaction of ammonia (NH ₃ ) with exhaust nitrogen oxide (NO _x ) to generate nitrogen (N ₂ ) and water (H ₂ O). . This technique is called selective catalytic reduction (SCR). Ammonia is difficult to handle in its pure form in an automotive environment and therefore usually with these systems, diesel exhaust fluid (DEF) and / or typically 32% urea (CO (NH ₂ )). ₂ ) A liquid aqueous urea solution having a concentration is used. The solution is called AUS-32 and is also known under the trade name AdBlue. The reducing agent solution is typically supplied to the hot exhaust stream using an injector and converted to ammonia before entering the catalyst. In particular, the solution is fed to a hot exhaust stream and converted to ammonia in the exhaust after undergoing thermolysis, or converted to ammonia and isocyanic acid (HNCO) after undergoing thermal decomposition. The isocyanic acid is then hydrolyzed with moisture present in the exhaust and converted to ammonia and carbon dioxide (CO ₂ ). As described above, ammonia generated from thermal decomposition and hydrolysis undergoes a catalytic reaction with nitrogen oxides.

  The freezing point of AUS-32 or AdBlue is −11 ° C. and it is expected that the system will freeze in cold weather. Since these fluids are aqueous, volume expansion occurs after transition to a solid state during freezing. An expanding solid can exert a large force on a closed volume such as an injector. Since such expansion can damage the injector unit, there are different SCR strategies to deal with reductant expansion.

  There are two known SCR system schemes on the market. That is, a purge system and a non-purge system. In a purge SCR system, the reducing agent urea and / or DEF solution is purged from the RDU when the vehicle engine is stopped. In a non-purge SCR system, the reducing agent remains in the RDU for the life of the vehicle. During normal operation of a non-purge SCR system, the RDU injector operates at a temperature above the freezing point of the reducing agent, so that the reducing agent in the RDU is maintained in a liquid state. However, when the vehicle engine is stopped in a non-purge SCR system, the RDU injector remains filled with the reducing agent, which makes the RDU injector susceptible to damage by the reducing agent expanded in the frozen state.

  The illustrative embodiments overcome the disadvantages found in existing RDU fluid injectors and provide an improved fluid injector for a non-purge SCR system that is at a temperature below the freezing point of the reductant and has reduced adverse effects due to RDU. According to one exemplary embodiment, the RDU includes a fluid inlet for receiving a reducing agent disposed at the first end of the fluid injector and a reducing agent disposed at the second end of the fluid injector. A fluid injector having a fluid outlet for discharging the fluid. The fluid injector defines a fluid path for the reducing agent from the fluid inlet to the fluid outlet. The fluid injector further includes a tube member having an end disposed at or near the fluid inlet of the fluid injector, the tube member configured to pass a reducing agent along the fluid path, and a fluid With respect to the direction of the reducing agent flow along the pre-fluid path from the fluid inlet of the fluid injector to the fluid outlet, the filter disposed in the tube member proximal to the fluid inlet of the injector, and into the tube member And a calibration filter tube disposed. The calibration filter tube has a first end portion adjacent to the filter and a second end portion, and further includes an axially defined hole extending through the calibration filter tube. And the bore defines at least a portion of a fluid path through the fluid injector. An actuator unit is disposed in the fluid injector downstream of the calibration filter tube, and the actuator unit is engaged with the second end of the calibration filter tube. The valve assembly is operably coupled to the actuator unit, and the position of the calibration filter tube within the tube member at least partially sets an opposing opening force for the valve assembly. The volume reducing member has a hole through which the calibration filter tube extends, and the volume reducing member occupies a space between the outer surface of the calibration filter tube and the inner surface of the tube member. doing. In one exemplary embodiment, the filter, the calibration filter tube, and the volume reduction member form an integral subassembly component of the fluid injector.

  In one exemplary embodiment, the volume reducing member is formed from a compressible material, the compressible material being one of a rubber composition and a closed cell foam.

  In one exemplary embodiment, the volume reducing member has a side wall that is corrugated in a direction along the longitudinal axis of the fluid injector.

  The fluid injector may further include a cap member that includes a sidewall that defines an interior space in which the filter is disposed, the sidewall being in contact with the first end of the calibration filter tube. ing. The first end portion of the calibration filter tube is disposed in the internal space of the cap member. The first end portion of the calibration filter tube includes a cap member such that the calibration filter tube, the cap member, the volume reduction member, and the filter form an integral subassembly component of the fluid injector. It may be attached to the side wall.

  The actuator unit is a pole piece arranged at a fixed position in the fluid injector, the pole piece having a hole defined so as to penetrate the pole piece in the axial direction, and movable in the fluid injector. An armature that is disposed and includes a pocket. The actuator unit may further include a coil disposed proximally of the pole piece and the armature and a spring disposed at least partially within the armature pocket. In one exemplary embodiment, the calibration filter tube is positioned in the hole of the pole piece such that the second end of the calibration filter tube contacts the spring, which is the current through the coil. When not, the armature is urged away from the pole piece so that the valve assembly is in a closed position that prevents the reducing agent from passing through the fluid outlet.

  The calibration filter tube includes a second portion extending axially from the first end portion of the calibration filter tube, and between the second portion and the second end portion of the calibration filter tube. And a third portion. The volume reduction member is disposed around the second portion, the third portion is disposed within the pole piece aperture, and the downstream end of the volume reduction member is in the direction of the reducing agent flow along the fluid path. With respect to the upstream end of the pole piece.

  The outer diameter of the second portion of the calibration filter tube may be larger than the outer diameter of the third portion of the calibration filter tube.

  In another exemplary embodiment, an RDU fluid injector is disposed at a first end of the fluid injector and is disposed at a second end of the fluid injector configured to receive fluid. A fluid outlet for discharging fluid, the fluid injector defining a fluid path for fluid from the fluid inlet to the fluid outlet. The tube member has an end located at or near the fluid inlet of the fluid injector, the tube member being configured to pass fluid along the fluid path. A filter is disposed in the tube member proximal to the fluid inlet of the fluid injector. The calibration filter tube is disposed in the tube member downstream of the filter as viewed in the fluid flow direction along the fluid path from the fluid inlet to the fluid outlet of the fluid injector. The calibration filter tube has a first end portion adjacent to the filter, a second end portion, and a hole defined to penetrate the calibration filter tube in the axial direction. The bore defines at least a portion of a fluid path through the fluid injector. An actuator unit is disposed in the fluid injector downstream of the calibration filter tube, and the actuator unit is engaged with the second end of the calibration filter tube. A valve assembly is operably coupled to the actuator unit, and the position of the calibration filter tube within the tube member sets the opposing opening force of the valve assembly. The fluid injector further includes a cap member, and the cap member has a side wall that defines an internal space in which the filter is disposed. In one exemplary embodiment, the side wall contacts the first end of the calibration filter tube and is attached to the first end, whereby the cap member, the filter, and the calibration filter tube are: It forms a single subassembly component of the fluid injector.

  Aspects of the present invention are described in detail below with reference to exemplary embodiments in conjunction with the drawings.

2 is a cross-sectional view illustrating an RDU for a non-purge SCR system according to one exemplary embodiment. It is sectional drawing which shows the fluid injector of RDU of FIG. FIG. 2 is an enlarged cross-sectional view illustrating an inlet portion of the fluid injector of the RDU illustrated in FIG. 1 according to one exemplary embodiment. FIG. 2 is an exploded perspective view showing components of the fluid injector of the RDU shown in FIG. 1 according to one exemplary embodiment. FIG. 2 is an enlarged cross-sectional view illustrating an outlet portion of the fluid injector of the RDU illustrated in FIG. 1 according to one exemplary embodiment. 2 is an enlarged cross-sectional view illustrating an inlet portion of the fluid injector of the RDU illustrated in FIG. 1 according to another exemplary embodiment. FIG. It is a disassembled perspective view which shows the component of the fluid injector shown in FIG. It is sectional drawing which shows the component of FIG. FIG. 6 is an enlarged cross-sectional view illustrating an inlet portion of the fluid injector of the RDU illustrated in FIG. 1 according to yet another exemplary embodiment. FIG. 10 is a cross-sectional view showing components of the fluid injector shown in FIG. 9. It is a perspective view which shows the component of the fluid injector shown in FIG. 2 is a cross-sectional view illustrating an inlet portion of the fluid injector of the RDU illustrated in FIG. 1 according to another exemplary embodiment. FIG. FIG. 13 is a cross-sectional view showing integrated components of the fluid injector shown in FIG. 12. It is a disassembled perspective view which shows the component of the fluid injector shown in FIG. 2 is a cross-sectional view illustrating an inlet portion of the fluid injector of the RDU illustrated in FIG. 1 according to another exemplary embodiment. FIG. FIG. 16 is a cross-sectional view showing integrated components of the fluid injector shown in FIG. 15. It is a disassembled perspective view which shows the component of the fluid injector shown in FIG.

  The following description of the exemplary embodiments is merely exemplary in nature and is not intended to limit the invention, its application or use.

  Exemplary embodiments relate to RDUs for non-purged SCR systems in which the damaging effects of reducing agents, DEF, and / or aqueous urea solutions that are typically frozen in an RDU injector are reduced.

  FIG. 1 illustrates an RDU 10 of a non-purge SCR system according to one exemplary embodiment. The RDU 10 includes a solenoid fluid injector, generally indicated at 12, which provides fluid metering and provides for the preparation of fluid spray into the vehicle exhaust path in metering applications. To do. That is, the fluid injector 12 is constructed and arranged in relation to an exhaust gas flow path upstream of a selective catalytic reduction (SCR) catalytic converter (not shown). The fluid injector 12 may be a solenoid fuel injector that is electrically operated. As shown in FIGS. 1 and 2, the fluid injector 12 includes an actuator unit having a coil 14 and a movable armature 16. The components of the injector 12 define a fluid path for the reducing agent, DEF, and / or urea solution through the injector 12. The RDU 10 is configured to inject a reducing agent, DEF, and / or urea solution into the exhaust path of the vehicle engine, and these reducing agent, DEF, and / or urea solution are described below for simplicity. Called “reducing agent”.

  As shown in FIG. 1, the fluid injector 12 is disposed within the internal carrier 18 of the RDU 10. The injector shield generally indicated by reference numeral 20 comprises an upper shield 20A and a lower shield 20B. The upper shield and the lower shield surround the injector 12 and are connected to the carrier 18 by bending the tongue of the flange 22 of the lower shield 20B so as to cover the carrier 18 and the shelf member of the upper shield 20A. . As a result, the shield 20 and the carrier 18 are fixed in position with respect to the injector 12.

  The inlet cup structure of the RDU 10, generally indicated by reference numeral 24 in FIG. 1, includes a cup 26 and a fluid supply pipe 28 formed integrally with the cup 26. The fluid supply pipe 28 communicates with a reducing agent source (not shown), which is supplied into the fluid inlet 30 of the injector 12 and from the injector fluid outlet 32 to the vehicle engine (not shown). Into the exhaust stream. The fluid inlet 30 of the injector 12 is in fluid communication with the fluid supply tube 28. The fluid outlet 32 is fluidly connected to the flange outlet 34 of the exhaust flange 36 that is directly coupled to the end of the lower shield 20B of the RDU 10.

  The injector 12 includes an injector body structure, and the components of the injector 12 are arranged in the injector body structure. The injector body structure includes a first injector body member 38 and a valve body member 40. A coil 14 and an armature 16 are disposed in the first injector body member, and a valve assembly of the injector 12 is at least partially disposed in the valve body member. The first injector body member 38 and the valve body member 40 are fixedly connected directly or indirectly to each other.

  With reference to FIGS. 1-3, the fluid injector 12 includes a tube member 42 disposed at least partially within a first injector body member 38. The outer surface of the tube member 42 is in contact with the inner surface of the first injector body member 38. The open end of the tube member 42 is disposed within the cup 26 and is in fluid communication with the fluid supply tube 28. Within the cup 26, an O-ring 44 is disposed between the inner surface of the cup and the outer surface of the tube member 42, near the open end of the tube member 42. The O-ring 44 functions to ensure that the reducing agent exiting the fluid supply pipe 28 passes through the open end of the pipe member 42 of the injector 12.

  The actuator unit of the fluid injector 12 further includes a pole piece 46 that is fixedly disposed within the first injector body member 38. The coil 14 at least partially surrounds the pole piece 46 and the armature 16. The pole piece 46 is disposed upstream of the armature 16 in the injector 12. The pole piece 46 has a central hole defined so as to penetrate the pole piece in the axial direction.

  Armature 16 includes a U-shaped section defining a pocket in which at least a portion of spring 50 is disposed. A spring 50 which is part of the actuator unit biases the movable armature 16 so that the armature 16 is spaced from the pole piece 46 when no current is passed through the coil 14. The spring 50 extends partially into the central hole of the pole piece 46. The end of the spring 50 extending into the pole piece 46 is in contact with the spring adjustment tube 52. The spring adjustment tube 52 is at least partially disposed in the center hole of the pole piece 46 upstream of the spring 50 (with respect to the direction of flow of reducing agent through the injector 12). The spring adjustment tube 52 has a hole defined so as to penetrate the spring adjustment tube in the axial direction. The through hole of the spring adjustment tube 52 partially defines a fluid path for the reducing agent in the fluid injector 12 and only defines a fluid path for the reducing agent in the pole piece 46. . The spring adjustment tube 52 is used to calibrate the dynamic flow of reducing agent through the fluid injector 12 by engagement with the spring 50.

  The armature 16 further includes one or more passages 60 (FIGS. 1 and 2) defined to penetrate the armature 16 from the interior of the pocket to the upstream end of the pin member 58. The passages 60 may be arranged at equal intervals around the armature 16. In one exemplary embodiment, the armature 16 includes a single passage defined entirely around the base of the pocket formed by the pocket wall 16A. The passage 60 allows the reducing agent to flow from the pocket of the armature 16 to the space around the upstream end of the pin member 58. Together, the pocket of the armature 16 and the passage 60 partially define the reducing agent fluid path of the fluid injector 12 and define only the portion of the fluid path that passes through or around the armature 16. .

  1, 2, and 5, the valve assembly of the injector 12 includes a seal member 54 and a seat portion 56. The seal member 54 is connected to the armature 16 via a pin member 58 disposed between the seal member 54 and the downstream end portion of the armature 16. The seal member 54, the pin member 58, and the armature 16 can be combined to form a single armature assembly. When the coil 14 is energized, the coil 14 generates an electromagnetic force that overcomes the biasing force of the spring 50 acting on the armature 16 and moves the armature 16 toward the pole piece 46. As the armature moves the pin member 58 correspondingly, the seal member 54 is lifted away from the seat 56 and moves away from the seat 56 to move the armature assembly to the open position so that the reducing agent passes through the fluid outlet 32. It reaches the flange outlet 34 and enters the exhaust path of the vehicle engine. When the coil 14 is de-energized, the electromagnetic force disappears and the spring 50 biases the armature 16, so that the armature 16 moves away from the pole piece 46, and as a result, the seal member 54 engages with the seat 56. Seal and change the armature assembly back to the closed position. Due to the armature assembly in the closed position, the reducing agent cannot flow through the seat 56 and the flange outlet 34 and cannot enter the exhaust path of the vehicle engine.

  As mentioned above, RDU 10 forms part of a non-purge SCR exhaust aftertreatment system. As a result, the reducing agent remains in the fluid injector 12 after the vehicle engine is turned off. In the exemplary embodiment, fluid injector 12 is configured to reduce the amount of reducing agent in fluid injector 12. In other words, the total volume of the fluid path for the reducing agent through the fluid injector 12 is reduced. Reducing the space for the reducing agent in the injector 12 reduces the amount of reducing agent in the RDU 10 that may potentially freeze, thereby damaging the expansion force from the frozen reducing agent. The damage rate of 12 is reduced.

  In order to reduce the volume of the reducing agent fluid path in the fluid injector 12, the thickness of the valve body member 40 is increased. Further, the pin member 58 is structured as a solid element so that the reducing agent does not penetrate the pin member but flows around the outer surface of the pin member 58. The space between the outer surface of pin 58 and the inner surface of valve body member 40 that partially defines the fluid path for the reducing agent through injector 12 is reduced. The only portion of this narrowed fluid path is the fluid path for the reducing agent between the armature 16 and the seat 56 in the fluid injector 12. The constricted fluid path between the pin 58 and the valve body member 40 provides sufficient reductant flow through the fluid injector 12 to perform reductant injection during normal operation of the RDU 10, while at the same time the injector 12 Maintaining a relatively small volume of reducing agent in the interior, reducing the risk of damage to the injector 12 due to freezing of the reducing agent in the injector.

  In addition, the diameter of the pocket of the armature 16 where the spring 50 is at least partially disposed is reduced, thereby increasing the thickness of the pocket wall 16A of the armature 16. In one exemplary embodiment, the thickness of the pocket wall 16A is between 45% and 75% of the pocket diameter, for example about 60%. The increased thickness of the pocket wall 16A, as well as the increased thickness of the valve body member 40, and the pin member 58, which is a solid pin, results in a stronger component of the injector 12, thus reducing the reducing agent. Increases resistance to freezing.

  Further, the hole in the spring adjustment tube 52 is sized to reduce the volume of the reducing agent fluid path in the injector 12. In one exemplary embodiment, the diameter of the hole in the spring adjustment tube 52 is between 12% and 22% of the outer diameter of the pole piece 46, in particular between 16% and 19%.

  FIG. 3 shows the upstream portion of the injector 12. A tube member 42 extends at least partially into the injector 12. The reducing agent fluid path through the injector 12 passes through the tube member 42. Injector 12 includes a filter 204 disposed within tube member 42 near the open end of tube member 42. Filter 204 is a structurally robust sintered metal filter, such as a stainless steel material, so that it can better withstand the expansion forces due to freezing of the reducing agent. The filter 204 may have a support external structure for added strength. As best seen in FIG. 3, the filter 204 is disposed within the cap member 206. The cap member 206 is substantially cylindrical and has a circumferentially extending side wall 206A that is sized to receive the filter 204 within the cap member. Is defined. The cap member 206 is sized to fit within the tube member 42, and in particular, the outer surface of the side wall 206 </ b> A of the cap member 206 is in contact with the inner surface of the tube member 42. The cap member 206 further includes an annular member 206B disposed along the axial end of the cap member 206 and extending radially inward from the sidewall 206A. The annular member 206B functions to maintain the filter 204 in a fixed position within the cap member 206. The cap member 206 is made of a composition such as metal.

  The injector 12 further includes a retaining ring 207 disposed within the tube member 42 that is upstream of and in contact with the cap member 206 as shown in FIGS. The holding ring 207 is fixed to the tube member 42 along the inner surface of the tube member. The retaining ring 207, which is fixed in position along the tube member 42, functions to maintain components downstream of the injector 12 in a fixed position within the first injector body member 38. In one exemplary embodiment, the retaining ring 207 is welded along the inner surface of the tube member 42. Such a weld connection is formed along the entire circumference of the upper edge of the retaining ring 207. However, it will be appreciated that other connection mechanisms may be utilized for securing the retaining ring 207 to the tube member 42.

  1-4, the injector 12 further includes a volume reducing member 208 that functions to further reduce the volume of the reducing agent fluid path in the injector 12. As shown in FIG. 4, the reduction member 208 has a substantially cylindrical shape, and has an upper (upstream) end and a bottom side (downstream) end. In one embodiment, the volume reducing member 208 is composed of a metal such as stainless steel. However, it should be understood that the volume reducing member 208 may be formed from another metal or metal composition. The outer surface of the volume reducing member 208 is sized to contact the inner surface of the tube member 42.

  The volume reducing member 208 is further provided with a hole 208 </ b> A (see FIG. 5) defined to penetrate the volume reducing member 208 in the axial direction from one axial (upper) end to the other axial (bottom side) end. 2 and FIG. 3). The hole 208A is located along the longitudinal axis of the volume reducing member 208, and the hole itself forms part of the fluid path for the reducing agent that passes through the injector 12. The holes 208A form only a fluid path for the reducing agent that passes through or around the volume reduction member 208. In one exemplary embodiment, the diameter of the hole 208A is between 12% and 20% of the outer diameter of the volume reducing member 208, for example about 16%. Since the volume reducing member 208 extends in the radial direction toward the inner surface of the tube member 42, and the diameter of the hole 208 </ b> A is smaller than the outer diameter of the volume reducing member 208, the volume reducing member 208 is used as the injector 12. Reduce the space or volume in which the reducing agent can stay, thereby reducing the volume of the internal reducing agent fluid path. The volume reduction member 208 further assists in holding the spring adjustment tube 52 in position within the injector 12, so that the spring adjustment tube 52 maintains the desired force on the spring 50, thereby preventing loss of calibration. In particular, the retaining ring 207 maintains the position of the filter 204 and thus maintains the position of the cap member 206. The cap member 206 maintains the position of the volume reducing member 208, and the volume reducing member maintains the position of the spring adjustment member 52.

  1 to 4, the fluid injector 12 further includes a volume compensation member 210 disposed between the bottom (downstream) end of the volume reducing member 208 and the upper side of the pole piece 46. . The volume compensation member 210 is made of an elastic material and is used to fill the space between the volume reduction member 208 and the pole piece 46, thereby further reducing the volume of the reducing agent fluid path in the injector 12. Can do. The volume compensating member 210 can be positioned in the injector 12 in a compressed state when assembled, and contacts the volume reducing member 208, the pole piece 46, the inner surface of the tube member 42, and the outer surface of the spring adjustment member 52. doing.

  FIG. 5 shows the downstream end portion of the fluid injector 12. As can be seen from the drawing, the seat portion 56 has a hole defined so as to penetrate the seat portion 56 in the axial direction. In one exemplary embodiment, the length of the through hole in the seat 56 is the volume of the reducing agent fluid path through the seat 56, in particular the bag-like volume below the seal band of the seat 56 that engages the seal member 54. Has been shortened to further reduce.

  According to one exemplary embodiment, the fluid injector 12 has a plurality of orifice disks 212 arranged in a stack. The orifice disk stack is disposed toward the downstream end of the seat 56. In the exemplary embodiment shown in FIG. 5, the disk stack includes a first disk 212A, which is configured to provide a desired spray pattern of reducing agent exiting the injector 12. It has one or more orifices. It will be appreciated that the size and position of the orifice of the first disk 212A can be varied and may depend in particular on the reducing agent metering requirements of the vehicle engine. The disk stack further includes a second disk 212B, which is disposed downstream of the first disk 212A and has an orifice through which the reducing agent spray passes. The second disk 212B has a thickness larger than that of the first disk 212A, is disposed with respect to the first disk 212A, and supports the first disk 212A. The deformation of the thinner first disk 212A due to the expansion force from the frozen reducing agent upstream of 212A is prevented.

  As described above, the fluid injector 12, particularly the fluid injector components, are configured to reduce the volume of the reducing agent fluid path within the injector 12. In the illustrated embodiment, the volume of the fluid path in the fluid injector 12 (coil 14, armature 16, pole piece 46, spring adjustment tube 52, volume reduction member 208, volume compensation member 210, filter 204, retaining ring 207, spring 50, the pin member 58, the seal member 54, the seat portion 56, the first injector body member 20A, and the valve body member 40), but the ratio of the components of the injector 12 to the volume is: 0.08 to 0.30, in particular 0.12 to 0.20, for example about 0.15. These volumes are in the first plane along the open end of the tube member 42, the plane perpendicular to the longitudinal axis of the fluid injector 12 (ie, the fluid inlet 30), and the second disk 212B. Calculated between the second plane (ie, fluid outlet 32) along the lowest (downstream) plane. The particular ratio of reducing agent path volume to injector component volume within the fluid injector 12 may vary depending on the number of costs and the performance of the associated factors, and is between about 0.08 and about 0.30. It will be appreciated that any value may be used. Providing a fluid injector having a reduced ratio of reductant fluid path volume to injector component volume falling within the range described above advantageously reduces the reductant in the injector 12 and reduces it in the injector 12. Reduces the probability that the RDU 10 will be damaged if the agent freezes.

  In another exemplary embodiment illustrated in FIGS. 6-8, the fluid injector 12 includes a volume reduction member 308 that provides many of the features of the volume reduction member 208 described above with respect to FIGS. Have. Similar to the volume reduction member 208, the volume reduction member 308 is constructed from stainless steel or a similar composition and is disposed within the tube member 42 of the fluid injector 12 between the volume compensation member 210 and the filter 204. Has been. However, the volume reducing member 308 has a first portion 308A and a second portion 308B. As shown in FIG. 7, each of the first portion 308A and the second portion 308B has a cylindrical shape, and the outer diameter of the first portion 308A is smaller than the outer diameter of the second portion 308B. . As will be described in more detail later, the outer diameter of the first portion 308A is smaller than the diameter of the second portion 308B by the thickness of the side wall 306A of the cap member 306. The volume reducing member 308 has an upper end (upstream) end and a bottom end (downstream) end, and these ends are in the axial direction of the first portion 308A and the second portion 308B, respectively. An end is formed. The outer surface of the second portion 308 </ b> B is sized to contact the inner surface of the tube member 42.

  As described above, the outer diameter of the first portion 308A of the volume reducing member 308 is smaller than the outer diameter of the second portion 308B. As shown in FIGS. 6-8, the volume reduction member 308 has an angled annular surface or skirt 308D that is axially connected to the outer surface of the first portion 308A; It extends between the outer surfaces of the second portion 308B and functions as a physical interface between these two outer surfaces. The angle of the angled surface 308D with respect to the longitudinal axis of the volume reduction member 308 and / or the injector 12 is acute. Optionally, the angle of angled surface 308D is perpendicular to the longitudinal axis of volume reduction member 308 and / or injector 12.

  The volume reducing member 308 further has a hole 308C defined so as to penetrate the volume reducing member 308 in the axial direction from one axial direction (upper side) end to the other axial direction (bottom side) end. doing. The hole 308C is located along the longitudinal axis of the volume reducing member 308, and the hole itself forms only the reducing agent fluid path for the reducing agent passing through the injector 12, and the volume reducing member 308 is It penetrates or forms part of the reducing agent fluid path around the volume reduction member 308. In one exemplary embodiment, the diameter of the hole 308C is between 12% and 20% of the outer diameter of the volume reducing member 308, for example about 16%. Since the volume reducing member 308 extends toward the inner surface of the tube member 42, and the diameter of the hole 308C is relatively small compared to the outer diameter of the volume reducing member 308, the volume reducing member 308 is provided with the injector 12. The amount of reducing agent in the injector 12 that occupies a predetermined volume within the injector 12 and reduces the space or volume of the reducing agent fluid path through the injector 12, thereby freezing and potentially damaging the injector 12. Reduce.

  The cap member 306 has some of the same features as the cap member 206 described above with respect to FIGS. As shown in FIG. 7, the cap member 306 has a side wall 306A that is substantially cylindrical and extends circumferentially, which side wall is for receiving the filter 204 within the cap member. Defines a sized internal volume. The cap member 306 is dimensioned to be fitted into the tube member 42, and in particular, the outer surface of the side wall 306 </ b> A of the cap member 306 is in contact with the inner surface of the tube member 42. The cap member 306 further includes an annular member 306B disposed along the axial (upstream) end of the cap member 306 and extending radially inward from the side wall 306A. The annular member 306B functions to maintain the filter 204 in a fixed position within the cap member 306. Similar to cap member 206, cap member 306 is constructed of a metal or similar composition and provides structural support to filter 204.

  In the illustrated embodiment, the cap member 306 is secured to the volume reduction member 308 by engaging the volume reduction member 308. In this way, the filter 204, cap member 306, and volume reduction member 308 form a single, integral, integrated component as shown in FIG. Having a single, integral component formed from filter 204, cap member 306, and volume reducing member 308 is preferably simple and complex for assembling injector 12 during injector manufacture. Not a process is possible.

  In the exemplary embodiment, cap member 306 is fitted over and engages at least a portion of first portion 308A of volume reduction member 308, as shown in FIGS. 6 and 8, or otherwise. Mounted in the form. In one exemplary embodiment, the cap member 306 forms a press-fit engagement with the first portion 308A. In another exemplary embodiment, the cap member 306 is welded to the first portion 308A, such as a fillet weld between the bottom surface 306C of the cap member 306 and the radially outer surface of the first portion 308A. In each such embodiment, the angled surface 308D provides sufficient space to secure the cap member 306 to the first portion 308A. The cap member 306 may be fixed to the first portion 308A of the volume reducing member 308 via another mechanism.

  Due to the cap member 306 fitted over the first portion 308A of the volume reducing member 308, the outer diameter of the side wall 306A is the same as or substantially the same as the outer diameter of the second portion 308B. See FIG. 6 and FIG.

  As described above, the volume reducing member 308 is made of a metal such as stainless steel according to one exemplary embodiment. In another exemplary embodiment, a portion of the second portion 308B is constructed from a plastic or similar composition. In particular, as shown in FIGS. 9 to 11, the first portion 308A and the first portion 308B-1 of the second portion 308B are formed as a single metal member, and the second portion 308B The second part 308B-2 is a plastic overmolded around the first part of the second part. FIG. 11 shows a first portion 308A of metal and a first portion 308B-1 of the second portion 308B. As shown in FIG. 10, the first portion 308B-1 of the second portion 308B includes an intermediate section 308B-3 extending in the (downstream) axial direction from the first portion 308A, and the intermediate section 308B-3. And a distal section 308B-4 extending axially (downstream) therefrom. The distal section 308B-4 extends from the longitudinal axis of the volume reduction member 308 (and / or the injector 12) more radially than the radial extension of the intermediate section 308B-3, thereby causing the beam Is forming. A second portion 308B-2 of the second portion 308B made of overmolded plastic or other similar composition is formed around the beam formed by the intermediate section 308B-3 and the distal section 308B-4. Thus, the volume reduction member 308 is formed as a single, integral, integrated component. As described above, the volume reduction member 308 is connected to the cap member 306, resulting in the volume reduction member 308, the filter 204, and the cap member 306 being a single unit for use in the assembled injector 12. Assembled components are formed.

  During assembly of the injector 12, a single assembly component (filter 204, cap member 306, volume reduction member 308) is inserted into the tube member 42 under pressure while in contact with the volume compensation member 210. Following insertion, the cap member 306 is welded to the tube member 42 along all intersections along the upper portion of the tube member 42, still under pressure. In one embodiment, the weld connection is fillet weld.

  FIG. 12 shows a fluid injector 12 according to another exemplary embodiment. In this embodiment, the fluid injector 12 includes a filter 204 and a cap member 306 in which the filter 204 is disposed as described above. Further, the fluid injector 12 has a calibration filter tube 402 and a volume reducing member 408. The calibration filter tube 402 has a hole 402A that is defined so as to penetrate the calibration filter tube 402 in the axial direction. At one (upstream) end of the calibration filter tube 402, the hole 402A is in fluid communication with the filter 204 to receive the reducing agent from the filter. At the other (downstream) end of the calibration filter tube 402, the hole 402 </ b> A supplies reducing agent to the armature 16. Thus, the calibration filter tube 402 forms part of the reducing agent fluid path through the fluid injector 12 and forms only such a fluid path from the filter 204 to the armature 16. . Since the diameter of the hole 402A of the calibration filter tube 402 is smaller than the inner diameter of the tube member 42, the volume of the reducing agent fluid path passing through the injector 12 is reduced. It is reduced.

  As shown in FIGS. 12-14, the calibration filter tube 402 further includes a first end portion 402B, which is at least partially disposed within the cap member 306. And is in contact with the filter 204. The first end portion 402B is substantially disk-shaped and has a side wall 402C that contacts the inner surface of the side wall 306A of the cap member 306. In one exemplary embodiment, the first end portion 402B of the calibration filter tube 402 is attached to the cap member 306, so that the cap member 306, the filter 204, and the calibration filter tube 402 are fluid injectors. To facilitate twelve simplified assemblies, a single, integral, integrated subassembly component is formed. In one exemplary embodiment, the cap member 306 engages the first end portion 402B, and in particular forms a press-fit engagement with the first end portion. In another exemplary embodiment, the cap member 306 has a first end such as a fillet weld between the axial end of the side wall 306A of the cap member 306 and the outer surface of the side wall 402C of the first portion 402A. It is welded to the portion 402B. It will be appreciated that, alternatively or additionally, the cap member 306 may be secured to the first end portion 402B of the calibration filter tube 402 using other techniques.

  The calibration filter tube 402 further includes an elongated second portion 402D extending in the axial direction from the first portion 402A, as shown in FIGS. The second portion 402D is sized to extend into the pole piece 46, so that the second end 402E opposite the first end portion 402B is the spring 50 (FIG. 12) is engaged. The second portion 402D is substantially cylindrical and has a hole 402A disposed therein. The calibration filter tube 402 further includes an annular tab 402F that extends radially outward from the outer surface of the second portion 402D. The tab 402F extends slightly outward from the outer surface of the calibration filter tube 402 and is disposed along the second portion 402D of the calibration filter tube 402. It contacts the inner surface of the defining pole piece 46. Due to such contact between the tab 402F and the central hole of the pole piece 46, the calibration filter tube 402 forms a press fit attachment with the pole piece 46.

  As described above, the second end portion 402E of the calibration filter tube 402 is in contact with and engaged with the spring 50. By the engagement of the calibration filter tube 402 and the spring 50 and by the engagement of the armature 16 and the spring 50, the calibration filter tube 402 is used to calibrate the dynamic flow of the reducing agent through the fluid injector 12. used. In particular, cap member 306, filter 204, and calibration filter tube 402, formed as a single, integral, integrated subassembly component, weld cap member 306 to the calibration filter tube. Previously, the calibration filter tube 402 is placed at a desired location within the tube member 42 to facilitate providing a desired calibrated force for the spring 50.

  The calibration filter tube 402 is made of a metal composition such as stainless steel.

  With continued reference to FIGS. 12-14, the injector 12 further includes a volume reduction member 408 disposed about the second portion 402D of the calibration filter tube 402. The volume reducing member 408 has a cylindrical shape and has a central hole defined so as to penetrate the volume reducing member 408 in the axial direction. The center hole of the volume reducing member 408 is sized to accommodate the calibration filter tube 402 therein. As shown in FIG. 12, the radially outer surface of the volume reducing member 408 contacts the inner surface of the tube member 42. One axial (upstream) end of the volume reducing member 408 is disposed near the first end portion 402B of the calibration filter tube 402 and is in contact with the first end portion 402B; The other axial (downstream) end of the volume reducing member 408 is disposed toward the upstream end of the pole piece 46 and is in contact with the upstream end of the pole piece 46. In this manner, the volume reduction member 408 has a second portion 402D of the calibration filter tube 402 that is located upstream of the pole piece 46 and downstream of the first end portion 402B of the calibration filter tube 402; A space between the pipe member 42 is occupied. In one exemplary embodiment, the volume reduction member 408 includes a single, integral, integrated subassembly component that, together with the cap member 306, filter 204, and calibration filter tube 402, reduces the volume reduction member 408. It is attached to the calibration filter tube 402 to form.

  In one exemplary embodiment, the volume reduction member 408 is constructed of a resilient and compressible material and is compressible at least axially along the fluid injector 12. An axially compressible volume reduction member 408 can adjust a single assembly component (cap member 306, filter 204, calibration filter tube 402) within tube member 42 relative to pole piece 46. So that the opening / closing force of the valve assembly of the fluid injector 12 can be easily calibrated as desired. In one embodiment, the volume reducing member 408 is composed of a closed cell foam. However, it should be understood that the volume reduction member 408 may be formed from another compressible material. In the case of a closed-cell foam, the volume reducing member 408 can be compressed in both the axial direction (longitudinal direction) and the radial direction (lateral direction). In one embodiment, the volume reduction member 408 is in the fluid injector 12 in a compressed state.

  15-17 illustrate a fluid injector 12 according to another exemplary embodiment. In this embodiment, the fluid injector 12 includes a filter 204 and a cap member 306 in which the filter 204 is disposed as described above. Further, the fluid injector 12 has a calibration filter tube 502. The calibration filter tube 502 has many features of the calibration filter tube 402 described above with respect to FIGS.

  The calibration filter tube 502 has a hole 502A defined so as to penetrate the calibration filter tube 502 in the axial direction. At one (upstream) end of the calibration filter tube 502, the hole 502A is in fluid communication with the filter 204 to receive the reducing agent from the filter. At the other (downstream) end of the calibration filter tube 502, the hole 502A supplies reducing agent through the fluid injector 12 to the armature 16. In this way, the calibration filter tube 502 forms part of the reducing agent fluid path and forms only such a fluid path from the filter 204 to the armature 16. Since the diameter of the hole 502A of the calibration filter pipe 502 is smaller than the inner diameter of the pipe member 42, the volume of the fluid path for the reducing agent passing through the injector 12 is reduced. The adverse effects of are reduced.

  As shown in FIGS. 15-17, the calibration filter tube 502 further includes a first end portion 502B, which is at least partially disposed within the cap member 306. And is in contact with the filter 204. The first end portion 502B is substantially disk-shaped and has a side wall 502C that contacts the inner surface of the side wall 306A of the cap member 306. In one exemplary embodiment, the first end portion 502B of the calibration filter tube 502 is attached to the cap member 306, so that the cap member 306, the filter 204, and the calibration filter tube 502 are fluid injectors. To facilitate twelve simplified assemblies, a single, integral, integrated subassembly component is formed. In one exemplary embodiment, the cap member 306 engages the first end portion 502B, and in particular forms a press-fit engagement with the first end portion. In another exemplary embodiment, the cap member 306 has a first end, such as a fillet weld between the axial end of the side wall 306A of the cap member 306 and the outer surface of the side wall 502C of the first portion 502B. It is welded to the portion 502B. In addition or alternatively, it is understood that the cap member 306 may be secured to the first end portion 502B of the calibration filter tube 502 using another technique.

  The calibration filter tube 502 further includes an elongated second portion 502D extending in the axial direction from the first portion 502A and an axial direction extending from the second portion 502D, as shown in FIGS. And an elongated third portion 502E. The third portion 502E is sized to extend into the pole piece 46, so that the second end of the calibration filter tube 502 opposite the first end portion 502B. 502F engages with the spring 50 (FIG. 12). The second portion 502D and the third portion 502E are substantially cylindrical and have a hole 502A disposed therein.

  In one exemplary embodiment, the outer diameter of the second portion 502D is greater than the outer diameter of the third portion 502E. The outer diameter of the third portion 502E is sized to be accommodated in the central hole of the pole piece 46.

  The calibration filter tube 502 further includes an annular tab 502G that extends radially outward from the outer surface of the third portion 502E (FIG. 17). The tab 502G extends slightly outward from the outer surface of the third portion 502E of the calibration filter tube 502 and is disposed axially along the third portion 502E of the calibration filter tube 502. Therefore, it contacts the inner surface of the pole piece 46 that defines the central hole of the pole piece. Due to such contact between the tab 502G and the central hole of the pole piece 46, the calibration filter tube 502 forms a press-fit engagement with the pole piece 46.

  The calibration filter tube 502 is made of a metal composition such as stainless steel.

  As described above, the second end portion 502F of the calibration filter tube 502 is in contact with and engaged with the spring 50. By engagement of the calibration filter tube 502 and the spring 50 and by engagement of the spring 50 and the armature 16, the calibration filter tube 502 is used to calibrate the dynamic flow of the reducing agent through the fluid injector 12. used. In particular, cap member 306, filter 204 and calibration filter tube 502 formed as a single, integral, integrated subassembly component welds cap member 306 to the calibration filter tube. Prior to placing the calibration filter tube 502 in the desired position within the tube member 42 and setting the opposite opening and closing forces for the valve assembly of the fluid injector 12, as desired for the spring 50. Facilitates providing a calibrated force.

  With continued reference to FIGS. 15-17, the injector 12 further includes a volume reduction member 508 disposed around the second portion 502D of the calibration filter tube 502. The volume reducing member 508 is substantially cylindrical and has a central hole defined to penetrate the volume reducing member 508 in the axial direction. The center hole of the volume reducing member 508 is sized to accommodate the second portion 502D of the calibration filter tube 502 therein. As shown in FIG. 12, the radially outer surface of the volume reducing member 508 contacts the inner surface of the tube member 42. One axial (upstream) end of the volume reducing member 508 is disposed near the first end portion 502B of the calibration filter tube 402 and is in contact with the first end portion 502B to reduce the volume. The other axial (downstream) end of the member 508 is disposed toward the upstream end of the pole piece 46 and is in contact with the upstream end of the pole piece 46. In this manner, the volume reduction member 508 has a second portion 502D of the calibration filter tube 502 located upstream of the pole piece 46 and downstream of the first end portion 502B of the calibration filter tube 502; A space between the pipe member 42 is occupied.

  In one exemplary embodiment, the volume reduction member 508 is constructed from a compressible material and is therefore compressible at least axially along the fluid injector 12. A volume reduction member 508 that is at least axially compressible adjusts a single assembly component (cap member 306, filter 204, calibration filter tube 502) within tube member 42 relative to pole piece 46. Can be positioned so that the valve assembly of the fluid injector 12 can be calibrated as desired. In one embodiment, the volume reduction member 508 is in the fluid injector 12 in a compressed state.

  As shown in FIGS. 15-17, the volume reducing member 508 has a side wall 508A extending between two axial ends. An axial end wall 508B downstream of the volume reducing member 508 extends radially inward from the side wall 508A and contacts the outer surface of the third portion 502E of the calibration filter tube 502. The upstream axial end of the volume reducing member 508 may be open and is in contact with the downstream surface of the first portion 502B of the calibration filter tube 502.

  The side wall 508A of the volume reducing member 508 is wavy in the axial direction as shown in FIGS. It exists in an alternating wavy pattern. By having a corrugated side wall 508A, the side wall 508A can be compressed in both the axial (longitudinal) and radial (lateral) directions, or otherwise partially contractible. In one exemplary embodiment, the volume reduction member 508 is constructed from a compressible elastic material, such as a rubber composite or other similar material. The volume reducing member 508 may be in the fluid injector 12 in a compressed state.

  Illustrative embodiments have been described herein in an illustrative form. It is understood that the terminology used is intended to be descriptive in nature rather than limiting in nature. Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The foregoing description is merely exemplary in nature and, thus, modifications can be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (20)

A reducing agent supply unit,
A fluid injector for receiving a reducing agent disposed at a first end of the fluid injector and disposed at a second end of the fluid injector, wherein the fluid injector is disposed at a first end of the fluid injector; A fluid outlet for releasing the reducing agent, and defining a fluid path for the reducing agent from the fluid inlet to the fluid outlet;
The fluid injector is
A tubular member having an end disposed at or near the fluid inlet of the fluid injector, the tubular member configured to pass a reducing agent along the fluid path;
A filter disposed within the tube member proximal to the fluid inlet of the fluid injector;
A calibration filter tube disposed in the tube member downstream of the filter with respect to the direction of the reducing agent flow along the fluid path from the fluid inlet to the fluid outlet of the fluid injector, The filter tube has a first end portion adjacent to the filter and a second end portion, and further includes a hole defined in an axial direction so as to penetrate the calibration filter tube. A calibration filter tube defining at least a portion of the fluid path through the fluid injector; and
An actuator unit disposed in the fluid injector downstream of the calibration filter tube, the actuator unit engaging the second end of the calibration filter tube;
A valve assembly operably coupled to the actuator unit, wherein the position of the calibration filter tube within the tube member at least partially sets an opposing opening force for the valve assembly. When,
A volume reduction member, wherein the calibration filter tube has a hole extending therethrough and occupies a space between an outer surface of the calibration filter tube and an inner surface of the tube member. A volume reducing member,
Have
The filter, the calibration filter tube, and the volume reducing member form a reducing agent supply unit that forms an integral subassembly component of a fluid injector.   The reducing agent supply unit according to claim 1, wherein the volume reducing member is made of a compressible material.   The reducing agent supply unit according to claim 2, wherein the compressible material includes one of a rubber composition and a closed cell foam.   The reducing agent supply unit according to claim 2, wherein the volume reducing member has a side wall, and the side wall of the volume reducing member is formed in a wave shape in a direction along a longitudinal axis of the fluid injector.   The fluid injector further includes a cap member, the cap member having a side wall defining an internal space in which the filter is disposed, the side wall being a first end of the calibration filter tube. The reducing agent supply unit according to claim 1, which is in contact with the reductant.   The reducing agent supply unit according to claim 5, wherein the first end portion of the calibration filter tube is disposed in the internal space of the cap member.   The first end portion of the calibration filter tube includes the calibration filter tube, the cap member, the volume reduction member, and the filter as an integral subassembly component of the fluid injector. The reducing agent supply unit according to claim 5, wherein the reducing agent supply unit is attached to a side wall of the cap member so as to be formed. The actuator unit is
A pole piece disposed at a fixed position in the fluid injector, the pole piece having a hole defined to penetrate the pole piece in an axial direction;
An armature movably disposed within the fluid injector and having a pocket;
A coil disposed proximate to the pole piece and the armature;
A spring disposed at least partially within the pocket of the armature;
The calibration filter tube is disposed in the hole of the pole piece such that the second end of the calibration filter tube contacts the spring, the spring passing through the coil. Urging the armature away from the pole piece when not present so that the valve assembly is in a closed position that prevents the reducing agent from passing through the fluid outlet;
The reducing agent supply unit according to claim 1.   The calibration filter tube includes a second portion extending in an axial direction from the first end portion of the calibration filter tube, the second portion, and the second portion of the calibration filter tube. A third portion located between the end portion, and the volume reduction member is disposed around the second portion, the third portion being located on the pole piece. The reducing agent according to claim 8, wherein the reducing agent is disposed in a hole, and a downstream end of the volume reducing member is adjacent to an upstream end of the pole piece with respect to a reducing agent flow direction along the fluid path. Supply unit.   The reducing agent supply unit according to claim 9, wherein an outer diameter of the second portion of the calibration filter tube is larger than an outer diameter of the third portion of the calibration filter tube. A fluid injector,
A fluid inlet disposed at a first end of the fluid injector and configured to receive a fluid; and a fluid outlet for discharging the fluid disposed at a second end of the fluid injector. The fluid injector defines a fluid path for fluid from the fluid inlet to the fluid outlet;
A tube member having an end disposed at or near the fluid inlet of the fluid injector, the tube member configured to pass fluid along the fluid path;
A filter disposed within the tube member proximal to the fluid inlet of the fluid injector;
A calibration filter tube disposed in the tube member downstream of the filter with respect to a direction of fluid flow along the fluid path from the fluid inlet to the fluid outlet of the fluid injector, The filter tube has a first end portion adjacent to the filter and a second end portion, and further includes a hole defined in an axial direction so as to penetrate the calibration filter tube. A calibration filter tube defining at least a portion of the fluid path through the fluid injector; and
An actuator unit disposed in the fluid injector downstream of the calibration filter tube, the actuator unit engaging the second end of the calibration filter tube;
A valve assembly operably coupled to the actuator unit, wherein the position of the calibration filter tube within the tube member sets an opposing opening force of the valve assembly; and
A cap member having a side wall defining an internal space, wherein a filter is disposed in the internal space, and the side wall contacts the first end of the calibration filter tube; A cap member attached to the first end, whereby the cap member, the filter, and the calibration filter tube form a single subassembly component of the fluid injector; ,
A fluid injector comprising:   The volume reduction member further includes a hole through which the calibration filter tube extends, and the volume reduction member includes an outer surface of the calibration filter tube, Occupying a space between the inner surface of the tube member, the volume reducing member, the cap member, the filter, and the calibration filter tube comprising a single subassembly component of the fluid injector. The fluid injector of claim 11, wherein the fluid injector is formed.   The fluid injector of claim 12, wherein the volume reducing member is compressible.   The fluid injector according to claim 13, wherein the volume reducing member is composed of one of a rubber composition and a closed cell foam.   The fluid injector according to claim 12, wherein the volume reducing member has a side wall, and the side wall of the volume reducing member is waved along a longitudinal axis of the fluid injector. The actuator unit is
A pole piece arranged at a fixed position in the fluid injector, the pole piece having a hole defined to penetrate the pole piece in an axial direction;
An armature movably disposed within the fluid injector and having a pocket;
A coil disposed proximate to the pole piece and the armature;
A spring disposed at least partially within the pocket of the armature;
The calibration filter tube is disposed in the hole of the pole piece such that the second end of the calibration filter tube contacts the spring, the spring passing through the coil. Urging the armature away from the pole piece when not present so that the valve assembly is in a closed position that prevents fluid from passing through the fluid outlet;
The fluid injector according to claim 12.   The calibration filter tube includes a second portion extending in an axial direction from the first end portion of the calibration filter tube, the second portion, and the second portion of the calibration filter tube. A third portion located between the end portion, and the volume reducing member is disposed around the second portion, and the third portion is the hole of the pole piece. 16. The fluid injector of claim 15, wherein the fluid injector is disposed within and the downstream end of the volume reducing member is adjacent to the upstream end of the pole piece with respect to the direction of fluid flow along the fluid path. .   The fluid injector of claim 17, wherein an outer diameter of the second portion of the calibration filter tube is larger than an outer diameter of the third portion of the calibration filter tube.   The calibration filter tube further includes an annular tab extending from the third portion of the calibration filter tube, the annular tab being disposed within the hole of the pole piece, The fluid injector of claim 17, forming a press fit engagement with the pole piece.   The fluid injector according to claim 11, wherein the first end portion of the calibration filter tube is disposed in the internal space of the cap member.

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