Patent Application
20220170435
The design of fuel injection systems greatly impacts the performance of combustion engines. One of the primary purposes of fuel injection systems is to deliver fuel to cylinders of a combustion engine during operation of the combustion engine. However, the manner in which a fuel injection system delivers fuel to the cylinders of the combustion engine directly impacts engine performance, noise characteristics, emissions, etc. Thus, fuel injection systems are carefully designed to inject fuel into the cylinders at a proper time during a combustion cycle. Fuel injection systems are also designed to deliver a precise amount of fuel to the cylinders of the combustion engine to meet the necessary power requirements for each cylinder of the engine.
Often times, however, fuel injection systems are required to control additional parameters to achieve adequate combustion events. For example, fuel injection systems control fuel atomization, bulk mixing, and air utilization. Fuel injection systems atomize fuel that is injected into the combustion engine during the combustion process to ensure that fuel atomizes into a fuel particle size necessary to vaporize the fuel. Fuel particles that are not atomized during the combustion process can burn poorly and are often exhausted out of the combustion engine. This can lead to increased emissions, smoke, decreased performance of the combustion engine, etc. Existing solutions for improving fuel atomization in conventional fuel systems include applying an electrostatic charge to fuel to improve atomization, introducing a magnetic field in the combustion chamber, replacing a fuel injector with an ultrasonic atomizer, among other solutions. However, these solutions often require complex systems and components that can be expensive, increase a propensity of a fuel injector (or fuel system) to fail, require increased maintenance, etc.
The Detailed Description is set forth with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different figures indicates similar or identical items. Furthermore, the drawings may be considered as providing an approximate depiction of the relative sizes of the individual components within individual figures. However, the drawings are not to scale, and the relative sizes of the individual components, both within individual figures and between the different figures, may vary from what is depicted. In particular, some of the figures may depict components as a certain size or shape, while other figures may depict the same components on a larger scale or differently shaped for the sake of clarity.
This disclosure is directed to a fuel injector nozzle (referred to herein as “an injector nozzle”) that is designed to enhance performance of a combustion cycle in a combustion engine. The injector nozzle is designed to improve atomization of fuel that is delivered to a cylinder of the combustion engine during the combustion cycle. In some examples, the combustion engine is a compression ignition diesel engine. However, the injector nozzle described herein can be used in other types of combustion engines.
The injector nozzle described herein can improve fuel particle size distribution of fuel that is injected into the cylinder of the combustion engine. For example, the injector nozzle described herein can inject fuel into the cylinder with improved variance of particle size. Typically, larger fuel particles travel further before ignition than smaller fuel particles. If fuel particles reach a piston of the combustion engine prior to ignition, the combustion of such fuel particles can cause damage to the piston or other components of the combustion engine. Furthermore, smaller fuel particles can ignite more quickly and/or more easily than a comparatively larger particle. Therefore, reducing fuel particle size can improve performance the combustion cycle and/or reduce emissions of the combustion cycle. Still further, once an exhaust valve opens in the cylinder of the combustion engine, any remaining non-ignited fuel particles can be drawn out of the cylinder, resulting in lost energy and/or increased emissions.
The injector nozzle described herein can improve particle distribution of fuel particle size by including a plurality of injection orifices having varying diameters. For example, the injector nozzle includes a nozzle body. The nozzle body further includes a nozzle cavity within the nozzle body. A nozzle tip defines an end of the nozzle body. When the injector nozzle is installed in a combustion engine as part of a fuel injector, the nozzle tip can be, at least partially, inserted into a cylinder of the combustion engine. In such an example, the plurality of injection orifices connects the nozzle cavity to the combustion chamber (i.e., the cylinder) of the combustion engine such that fuel flows through the nozzle cavity into the combustion chamber of the combustion engine.
The injector nozzle can include one or more first injection orifices having a first diameter. The one or more first injection orifices can be located at a first distance from an end (i.e., the nozzle tip) of the nozzle body. The injector nozzle can also include one or more second injection orifices having a second diameter. In some examples, the second diameter is less than the first diameter. For example, the second diameter can be approximately half of the first diameter. However, the first diameter and the second diameter can include various dimensions. Furthermore, the one or more second injection orifices can be located at a second distance from the end of the nozzle body. The second distance can be less than the first distance such that the one or more second injection orifices are closer to the end of the nozzle body than the one or more first injection orifices. In some examples, a length of the nozzle body extends in a vertical direction and individual ones of the one or more second injection orifices are offset from individual ones of the one or more first injection orifices in a horizontal direction.
By including one or more second injection orifices that are smaller than the one or more first injection orifices, the injector nozzle injects fuel particles into the cylinder at varying particle sizes. Thus, the smaller fuel particles can ignite prior to the larger fuel particles and, in some examples, can travel a shorter distance than the larger particles prior to ignition. Furthermore, by igniting the smaller fuel particles before the larger fuel particles, the ignition of the smaller fuel particles can cause ignition of the larger fuel particles. Therefore, the injector nozzle can create multiple ignition events (i.e., ignition of small fuel particles and ignition of large fuel particles) in a single in injection event. Such a design of the injector nozzle can increase performance of a combustion event and/or reduce emissions associated with the combustion event.
The injector nozzle described herein can also improve fuel injection into the cylinder by reducing and/or eliminating choked flow through the plurality of injection orifices. For example, the plurality of injection orifices includes an exterior edge on an outside surface of the nozzle body and an interior edge on an inside surface of the nozzle body. The inside surface of the nozzle body defines the nozzle cavity. In conventional fuel injector nozzles, the exterior edge and the interior edge of the injection orifices are approximately 90 degrees. Therefore, as fuel enters an injection orifice, the flow of fuel through the injection orifice can be choked through the injection orifice. The injector nozzle described herein can include a rounded (or chamfered) interior edge to reduce and/or eliminate choked flow through individual injection orifices of the plurality of injection orifices. Following the example described previously, the one or more first injection orifices and the one or more second injection orifices can include a rounded or chamfered interior edge. The interior edge can be rounded or chamfered by flowing an abrasive-laden fluid through the plurality of injection orifices in an abrasive flow machining (AFM) process.
The injector nozzle described herein can also improve fuel atomization by including a counterbored hole on an exterior surface of the nozzle body that is coaxial with individual injection orifices of the plurality of injection orifices. The plurality of injection orifices can include a first length and the counterbore holes include a second length that is less than the first length. In some examples, the plurality of injection orifices includes a first diameter and the counterbored holes include a second diameter that is greater than the first diameter. The second diameter can be approximately twice the size of the first diameter. However, a ratio between the second diameter and the first diameter can vary. In some examples, the counterbore holes include an exterior hole edge on an outside surface of the nozzle body and an interior hole edge on an inside surface of the counterbore hole. In such example, the interior hole edge is rounded. By rounding the interior hole edge, fuel is drawn out of the injection orifice quicker when compared with an interior hole edge that is a square edge. For example, by rounding the interior hole edge, the fuel can maintain laminar flow as the fuel is injected out of the injection orifices into the cylinder. Conversely, if the interior hole edge is a square edge, the fuel can experience drag in the corners and/or turbulent flow, thereby slowing fuel injection into the cylinder.
Furthermore, by including a counterbore hole that is coaxial with an injection orifice, fuel that is injected into the cylinder can disperse sooner than fuel injected through an injection orifice that does not include a counterbore hole. Therefore, the counterbore hole can improve atomization of the fuel that is injected into the cylinder. In some examples, the plurality of injection orifices can include a counterbore hole on an exterior surface of the nozzle body and a rounded or chamfered interior edge on the interior surface of the nozzle body. Furthermore, following the example described previously, the one or more first injection orifices having a first diameter can include counterbored holes on an exterior surface of the nozzle body and/or the one or more second injection orifices having a second diameter can include counterbored holes on the exterior surface of the nozzle body.
Specific examples are described herein in order to meet statutory requirements. However, the description itself is not intended to limit the scope of the claims. It is contemplated that the claims might also be implemented in other ways, to include different elements or combinations of elements similar or equivalent to what is described in this document, in conjunction with other present or future technologies.
The present disclosure provides an overall understanding of the principles of the structure, function, manufacture, and use of the apparatuses and methods described herein. One or more examples of the present disclosure are illustrated in the accompanying drawings. Those of ordinary skill in the art will understand that the apparatuses and methods specifically described herein and illustrated in the accompanying drawings are non-limiting. The features illustrated or described in connection with one example can be combined with the features of other examples, including as between apparatuses and methods. Such modifications and variations are intended to be included within the scope of the appended claims.
Additional details are described below with reference to the accompanying figures.
As mentioned previously, atomization of the fuel in the combustion chamber 102 directly impacts performance of the combustion engine 100. Furthermore, adequate particle size distribution is necessary to reduce emission of the combustion engine 100. Conversely, inadequate particle size distribution and/or particles that are too large can cause decreased performance, increased emissions and/or smoke, and/or damage to components of the combustion engine 100.
As shown in
In some examples, the one or more second injection orifices 202(2) are located at a second distance from the first end (i.e., the nozzle tip 204) of the nozzle body 206. The second distance can be less than the first distance such that the one or more second injection orifices 202(2) are closer to the first end of the nozzle body 206 than the one or more first injection orifices 202(1). By positioning the one or more second injection orifices 202(2) closer to the first end of the nozzle body, the injector nozzle 112 can inject smaller fuel particles lower in the combustion chamber 102 relative to larger fuel particles that are injected through the one or more first injection orifices 202(1). The smaller fuel particles injected through the one or more second injection orifices 202(2) can initiate combustion prior to larger fuel particles due to their smaller relative size. Thereby, combustion of the fuel in the combustion chamber 102 can be initiated by the smaller fuel particles injected through the one or more second injection orifices 202(2). In some examples, the smaller fuel particles can act as a pilot injection without requiring multiple injection events. However, the fuel injector 110 can be configured to inject fuel into the combustion chamber 102 multiple times during each cycle of a combustion process. In some examples, a length of the nozzle body extends in a vertical (or first) direction and the one or more second injection orifices 202(2) are offset from the one or more first injection orifices 202(1) in a horizontal (or second) direction that is perpendicular to the first direction. The profile of the nozzle body 206 can vary and is not limited to the profile of the nozzle body 206 shown in
In some examples, the plurality of injection orifices 202 can have a first length and the counterbore holes 502 can include a second length that is less than the first length. However, in some examples, the second length of the counterbore holes 502 can be equal to or greater than the first length. By including a counterbore hole 502 that includes a rounded interior hole edge 604, fuel that is injected into the cylinder 104 can disperse sooner than fuel injected through an injection orifice 202 that does not include a counterbore hole. Therefore, the counterbore hole 502 can improve atomization of the fuel that is injected into the cylinder 104 compared to other fuel injector nozzles.
As described previously, the counterbore holes 502 can be formed by an EDM process. In some examples, during the EDM process, an injection orifice 202 is chased with a wire (such as a tungsten wire) to create the counterbore hole 502. Typical EDM processes chase a hole the entire length of the counterbore to create a square interior edge. However, the counterbore holes 502 described herein are formed by chasing the injection orifice to approximately half of the desired length of the counterbore hole 502 and allowing water to pass around a deformed face of the wire in order to create the rounded interior hole edge 604. Thus, the counterbore hole 502 is chased to a desired length and the counterbore hole 502 includes a rounded interior hole edge 604. In some examples, each of the plurality of injection orifices 202 can include counterbore holes 502. Alternatively, select ones (and less than all) of the plurality of injection orifices 202 can include counterbore holes 502. As described above, the injector nozzle 112 can include one or more first injection orifices 202(1) having a first diameter that include counterbore holes 502 and/or one or more second injection orifices 202(2) having a second diameter that include counterbore holes 502.
While the foregoing describes specific examples, it is to be understood that the scope of the claims is not limited to any of these specific examples. Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the claims should not be considered limited to the example chosen for purposes of disclosure, and cover all changes and modifications which do not constitute departures from the spirit and scope of this application.
Although the application describes specific structural features and/or methodological acts, it is to be understood that the claims are not necessarily limited to the specific features or acts described. Rather, the specific features and acts are merely illustrative of one or more examples that fall within the scope of the claims. Moreover, unless explicitly stated otherwise, any of the examples set forth herein are combinable.
