Patent Application
20240084768
The present disclosure generally relates to fuel injectors for an engine, and more specifically, to fuel injectors that produce improved hydraulic separation capabilities.
Internal combustion engines use high pressure in the delivery of fuel for combustion. Internal combustion engines use fuel injectors having needle valves to deliver fuel. When such needle valves are open, fuel flows therein. Accordingly, needle valves facilitate and regulate fuel flow to the internal combustion engine for engine operation.
Fuel injectors may include an armature to electromagnetically regulate fuel flow through the fuel injector. The armature typically performs sequential movements in the form of pulses along a designated path of travel. A time gap between an end of one pulse and a start of a next pulse is called hydraulic separation. Smaller hydraulic separation accommodates more pulses in a given combustion time frame and correspondingly minimizes injector multi-pulse fueling errors.
A fuel injector with a flow control valve is disclosed in U.S. Published Patent Application No. 2009/0267008. In this application, an electromagnetic valve includes an extra-high pressure injection system control valve having soft metal powder particles in a magnetic stator core. Electroless nickel plating is applied to the stator core to provide an intermediate surface to absorb grinding wheel stress as a working face is exposed during manufacturing, as well as an external compression layer or casing to hold or encapsulate the powder particles in place and together during assembly and use.
According to principles of the present disclosure, fuel injector can include a body and an armature assembly. The body can have a longitudinal axis extending between a proximal end and a distal end of the body. The armature assembly can be configured to be received within the body and including an armature and a stator that are arranged so as to form a gap therebetween. The armature can be configured to move along the longitudinal axis between first and second positions relative to the stator. In this regard, the armature can move toward the stator as the armature moves from the first position to the second position. Under these circumstances, fuel can be forced out of the gap. The armature can move away from the stator as the armature moves from the second position to the first position. Under these circumstances, fuel can be drawn into the gap. The armature can include a hydraulic separation feature configured to improve hydraulic separation of the armature such that a travel time between the first and second positions are reduced as the armature comes to rest. The hydraulic separation feature can include at least one of a modified mass, a modified overtravel diameter, and one or more diffusion holes.
In examples, the travel time between the first and second positions can include the travel time between the first position and the second position as well as the travel time over an overtravel distance.
In examples, the hydraulic separation feature can include at least one of an optimized mass, an optimized overtravel diameter, and one or more diffusion holes. In examples, the hydraulic separation feature can include an optimized mass and an optimized overtravel diameter. In examples, the hydraulic separation feature can include an optimized mass and one or more diffusion holes.
In examples, when the one or more diffusion holes can be a plurality of diffusion holes through a flange of the armature. The plurality of diffusion holes can be radially spaced about the longitudinal axis. In examples, the plurality of diffusion holes can include at least 4 diffusion holes. In examples, a diameter of each diffusion hole in the one or more diffusion holes can be from about 1 millimeter to about 2 millimeters.
In examples, the optimized mass can be from about 7 grams to about 8 grams.
In examples, the optimized overtravel diameter can be an overtravel diameter that is reduced along the length of the armature in the direction from the proximal end to the distal end. In examples, the overtravel diameter is transitioned to from a first diameter of a nominal diameter to the overtravel diameter via a chamfered transition between the upper diameter and the overtravel diameter. In examples, the overtravel diameter near the distal end of the armature can less than or equal to about 5 millimeters over a length of the armature.
Disclosed herein are methods of optimizing an armature in a fuel injector for reduced travel time. A method can include selecting the armature, which can be configured to travel between first and second positions relative to a stator included in the fuel injector. The method can include machining a hydraulic separation feature into a body of the armature. The hydraulic separation feature can be configured to improve hydraulic separation of the armature such that a travel time between the first and second positions are reduced as the armature comes to rest. The hydraulic separation feature can include at least one of a modified mass, a modified overtravel diameter, and one or more diffusion holes.
In examples of the method, the travel time between the first and second positions can include the travel time between the first position and the second position as well as the travel time over an overtravel distance. In examples of the method, the hydraulic separation feature can include at least one of an optimized mass, an optimized overtravel diameter, one or more diffusion holes.
In examples of the method, the hydraulic separation feature can include each of an optimized mass and an optimized overtravel diameter or each of the hydraulic separation feature includes an optimized mass and one or more diffusion holes.
In examples of the method, the hydraulic separation feature can include one or more diffusion holes. The one or more diffusion holes can be a plurality of diffusion holes through a flange of the armature. The plurality of diffusion holes can be radially spaced about the longitudinal axis.
In examples of the method, the optimized overtravel diameter is an overtravel diameter can be reduced along the length of the armature in the direction from the proximal end to the distal end. The overtravel diameter can be transitioned to from a first diameter of a nominal diameter to the overtravel diameter via a chamfered transition between the upper diameter and the overtravel diameter. The overtravel diameter near the distal end of the armature can be less than or equal to about 5 millimeters over a length of the armature.
Disclosed herein is an armature for a fuel injector. The fuel injector can have a longitudinal axis extending centrally therethrough. The armature can be configured to be positioned adjacent a gap in the fuel injector and configured to move along the longitudinal axis between first and second positions. In this regard, the armature can move in a proximal direction as the armature moves from the first position to the second position. Under these circumstances, fuel is forced out of the gap. The armature can move in the distal direction as the armature moves from the second position to the first position. Under these circumstances, fuel can be drawn into the gap. The armature can include a hydraulic separation feature configured to improve hydraulic separation of the armature such that a travel time between the first and second positions are reduced as the armature comes to rest. The hydraulic separation feature includes at least one of a modified mass, a modified overtravel diameter, and one or more diffusion holes.
In examples, the travel time between the first and second positions can include the travel time between the first position and the second position as well as the travel time over an overtravel distance. In examples, the hydraulic separation feature can include at least one of an optimized mass, an optimized overtravel diameter, and one or more diffusion holes.
In examples, the hydraulic separation feature can include an optimized mass and an optimized overtravel diameter, or the hydraulic separation feature can include an optimized mass and one or more diffusion holes.
Additional features and advantages of the present disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiments exemplifying the disclosure as presently perceived.
The above-mentioned and other features and advantages of this disclosure, and the manner of obtaining them, will become more apparent, and will be better understood by reference to the following description of the exemplary embodiments taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of various features and components according to the present disclosure, the drawings are not necessarily to scale and certain features can be exaggerated in order to better illustrate and explain the present disclosure. The exemplification set out herein illustrates an embodiment of the invention, and such an exemplification is not to be construed as limiting the scope of the invention in any manner.
The present disclosure advantageously provides design considerations for flow control valves for fuel injectors to improve hydraulic separation capabilities of an armature in a fuel injector. Disclosed herein are improved fuel injectors that are advantageously structured to reduce the travel time of the armature in the fuel injector. Moreover, some embodiments of such fuel injectors may provide smaller hydraulic separation, which may minimize injector multi-pulse fueling errors.
As shown in these figures, in general, the armature 140 includes an armature body 200 (see
As shown in
The armature 140 can be configured to be received within the body 1012 and arranged relative to the stator assembly 136 so as to form the gap 166 therebetween. The armature 140 can be configured to move along the longitudinal axis 162 between first and second positions relative to the stator assembly 136 and stator 137. The first position 141 of the armature 140, as shown for example in
In this regard, the armature 140 can move toward the stator 137 as the armature 140 moves from the first position to the second position. Under these circumstances, fuel can be forced out of the gap 166. The armature 140 can move away from the stator 137 as the armature 140 moves from the second position to the first position. Under these circumstances, fuel can be drawn into the gap 166. The armature 140 includes a hydraulic separation feature in accordance with one or more embodiments described herein and configured to improve hydraulic separation of the armature 140 such that a travel time between the first and second positions can be reduced as compared to previous embodiments as the armature 140 comes to rest. In examples, the travel time between the first and second positions can include the travel time between the first position and the second position as well as the travel time over an overtravel distance.
For example, the armature body 200 is configured to enable the movement of the armature 140 as described herein. More specifically, the armature 140 reciprocally moves within a bore 202 of the fuel injector 1000. The flange 142 is configured to force fluid, such as fuel, through the gap 166 as the armature 140 moves from the first position toward the second position. As the armature 140 moves from the second position toward the first position, the flange 142 is configured to draw the fluid into the gap 166.
The hydraulic separation feature is defined in or along the body 200 of the armature 140. The hydraulic separation feature interacts with a fluid flow, such as a fuel flow, around the armature 140. For example, as the armature 140 travels between the first and second positions, the hydraulic separation feature alleviates pressure in the fluid by, for example, allowing some fluid flow through the body 200 and/or creating less pressure in the fluid as compared to armatures without hydraulic separation features.
In this regard,
In examples, the one or more diffusion holes 300 can be a plurality of diffusion holes 300 defined through the flange 142 of the armature 140. The plurality of diffusion holes 300 can be radially spaced about the longitudinal axis 162. In examples, the plurality of diffusion holes 300 can include at least 4 (e.g., 5, 7, 8, 11, and the like) diffusion holes 300. Any number of diffusion holes, their cross section (variable or constant), their arrangement (e.g., symmetrical, asymmetrical, staggered, etc.) are considered within the scope of this disclosure though not discussed herein at length. The specific examples herein are intended to be illustrative of this principle.
An example armature 140 in the first configuration will now be discussed in detail. The diffusion holes 300 can be parallel to the center or longitudinal axis 162 of armature 140. In the illustrated example, there are 4 diffusion holes 300 of approximately 1.1 mm diameter, symmetrically distributed, at a radially fixed distance from the center axis of armature 140. In this regard, the diffusion holes 300 are spaced about 5.65 mm from the center axis. Range of diffusion hole sizes can vary from about 0.85 to 1.3 mm in accordance with some aspects. Center-to-center spacing of the diffusion holes 300 can range from about 10.5 to 12.5 mm in accordance with some aspects.
The diffusion holes 300 can influence fluid flow during all points of travel of the armature 140. During upward travel of the armature 140, fluid on an upper surface 148 of the flange 142 compresses and can lead to high pressure spikes. Presence of diffusion holes 300 helps in diffusing squeeze film pressure spikes during armature travel and hence can increase a velocity of the armature 140. During downward travel of the armature 140, fluid, such as fuel, flows from a lower surface 149 of the flange 142 to the upper surface 148 of the flange 142 via the diffusion holes 300 and thereby can reduce hydraulic drag on the armature 140 and increase the downward velocity. This helps the armature 140 to enter with a comparative higher velocity than known armatures into overtravel. During overtravel, the armature 140 moves downward and then upward as the armature 140 comes to rest. Fluid flowing via the diffusion holes 300 helps in further reducing the hydraulic drag on flange 142 during overtravel and helps the armature 140 to cover the overtravel distance in a shorter amount of time before coming to rest.
For instance, with mass optimization there can be less spring compression and faster acceleration with the lower mass. This can result in the armature 140 coming to rest in a shorter duration of time. In examples, mass can be removed from the lower surface 149 of the flange 142 (e.g., forming a chamfer 150 in the direction radially outward from the center axis to the periphery of the flange 142) beyond the diameter portion 151. For instance, the flange 142 can have a thickness 153 of between 1.2 and 1.5 mm (e.g., 1.34 mm, 1.42 mm) and include a chamfer of about 10 to 15 degrees (e.g., 12, 13, 15 degrees) radially inward from the periphery of the flange 142. In other examples, the flange 142 can include a chamfer of about 20 to 30 degrees (e.g., 21, 24, 26 degrees) radially inward from the periphery of the flange 142. In addition, the upper diameter 144 can be reduced beyond the diameter portion 151 by about 1% (e.g., from 9.6 mm diameter to a 9.5 mm diameter) while having minimal impact on magnetic forces required to operate the armature 140. In this regard, a chamfer at the periphery of the upper diameter can be removed.
In examples, the overtravel diameter 152 is near the distal end 156 of the armature 140 and can be less than or equal to about 5 millimeters over a length 153 of the armature 140. In examples, the length 153 is about 1.5 mm. For instance, overtravel diameter 152 can be reduced from about 5.55 mm to be about 4.95 mm through a step chamfer design. In examples, the overtravel diameter 152 is transitioned to from a first diameter of a nominal diameter of a portion 500 of the body 200 to the overtravel diameter 152 via a chamfered transition 502 between the nominal diameter at the portion 500 and the overtravel diameter 152. The first diameter can be greater than the second diameter (e.g., by a multiple of about 2). In examples, the first diameter is about 9.5 mm and the second diameter is about 4 mm. Chamfered transition 502 can help in controlling part-to-part variation through tighter control of upper diameter 146 or overtravel diameter 152 in manufacturing. A range of percentage reduction can vary from about 15 to 55%. By reducing the length of the overtravel diameter 152 in this way, a corresponding face or face surface area (which can be in contact with the squeeze film), the armature 140 faces lesser squeeze film resistance during overtravel motion. This helps to cover the overtravel distance in a shorter amount of time before coming to rest. It should also be noted that reducing the overtravel diameter 152 also reduces the face or face surface area of the lower surface (at a distal end) of the armature 140. In examples, the chamfered section 502 can be about 160 degrees, and the resulting face or face surface is between 1 and 2 mm.
As noted above, certain design features can be combined.
Disclosed herein are methods of optimizing an armature 140 in a fuel injector 1000 for reduced travel time. These methods can include any of the functions and features as it pertains to the devices and systems discussed elsewhere herein.
As shown in
In examples of the method, the travel time between the first and second positions can include the travel time between the first position and the second position as well as the travel time over an overtravel distance. In examples of the method, the hydraulic separation feature can include at least one of a modified mass structure, a modified overtravel diameter structure, and/or one or more diffusion holes. In examples of the method, the hydraulic separation feature can include each of a modified mass structure and a modified overtravel diameter structure or each of a modified mass structure and one or more diffusion holes. In examples of the method, the hydraulic separation feature can include one or more diffusion holes. The one or more diffusion holes can be a plurality of diffusion holes through a flange of the armature. The plurality of diffusion holes can be radially spaced about the longitudinal axis.
Machining the hydraulic separation feature into a body of the armature may take a variety of forms. For instance, this machining can be performed such that the travel time between the first and second positions includes the travel time between the first position and the second position as well as the travel time over an overtravel distance. Machining the hydraulic separation feature into a body of the armature includes either machining the body of the armature to have the modified mass structure and the modified overtravel diameter structure or machining the body of the armature to have the modified mass structure and the one or more diffusion holes. Machining the hydraulic separation feature into a body of the armature includes machining the body of the armature to have the one or more diffusion holes. Optionally, the one or more diffusion holes is a plurality of diffusion holes through a flange of the armature. Optionally, the diffusion holes are radially spaced about a longitudinal axis of the fuel injector. Machining the hydraulic separation feature into a body of the armature may be done to include the modified overtravel diameter structure. Optionally, the overtravel diameter structure is reduced along a length of the armature in a direction from a proximal end of the armature to a distal end of the armature such that the overtravel diameter is transitioned to from a first diameter of a nominal diameter to the overtravel diameter via a chamfered transition between the nominal diameter and the overtravel diameter and the overtravel diameter is less than or equal to about 5 millimeters over the length of the armature.
As shown at step 1212, the armature 140 is moved in a second or distal direction between the second position and the first position. The armature 140 is positioned at a location spaced apart from the stator assembly 136 by the gap 166 by this step 1212, as shown by step 1222. By these steps 1212 and 1222, fuel is drawn into the gap 166 as shown by step 1220. Pressures on the fuel injector components, such as the armature 140 and the stator assembly 136, may be reduced by the hydraulic separation features during the operation of method 1200.
As used herein, the modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (for example, it includes at least the degree of error associated with the measurement of the particular quantity). When used in context of a range, the modifier “about” should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the range “from about 2 to about 4” also disclosed the range “from 2 to 4.”
It is well understood that methods that include one or more steps, the order listed is not a limitation of the claim unless there are explicit or implicit statements to the contrary in the specification or claim itself. It is also well settled that the illustrated methods are just some examples of many examples disclosed, and certain steps can be added or omitted without departing from the scope of this disclosure. Such steps can include incorporating devices, systems, or methods or components thereof as well as what is well understood, routine, and conventional in the art.
For the purposes of promoting an understanding of the principles of the present disclosure, reference is now made to the embodiments illustrated in the drawings, which are described below. The exemplary embodiments disclosed herein are not intended to be exhaustive or to limit the disclosure to the precise form disclosed in the following detailed description. Rather, these exemplary embodiments were chosen and described so that others skilled in the art can utilize their teachings. It is not beyond the scope of this disclosure to have a number (e.g., more than one or all) the features in a given embodiment to be used across all embodiments.
Throughout this disclosure, the words “distal,” “lower,” and words of similar effect will correspond to portions of the fuel injector that are downstream relative to other portions in terms of the flow of fuel from the injector to the combustion chamber of an engine, such as the injector openings or spray holes. Similarly, the words “proximal,” “upper,” and words of similar effect will correspond to portions of the fuel injector that are upstream of the downstream portions.
The connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections can be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that can cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements. The scope is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone can be present in an embodiment, B alone can be present in an embodiment, C alone can be present in an embodiment, or that any combination of the elements A, B or C can be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C.
In the detailed description herein, references to “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described can include a particular feature, structure, or characteristic, but every embodiment can not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art with the benefit of the present disclosure to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments.
Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f), unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus
While the present disclosure has been described as having an exemplary design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practices in the art to which this invention pertains.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202111024920 | Jun 2021 | IN | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US22/32169 | Jun 2022 | US |
| Child | 18514250 | US |
