Patent Application
20240295205
The present disclosure relates generally to a boot in a fuel system, and more particularly to a boot and attached filter.
The fuel system in a modern internal combustion engine is often the most complex and expensive part of the equipment. Fuel is typically pressurized to a range of pressures depending upon application and injection location, and delivered for combustion in one or more shots of fuel into a cylinder by way of precisely controlling electrically and/or hydraulically actuated components in fuel injectors. Pressurized fuel systems can require specialized sealing and fuel containment apparatus. For regulatory and other purposes higher pressure portions of a fuel system often employ double-walled containment, such that in the event of a liquid fuel and/or fuel vapor leak fuel is contained in a secondary system outside of the highly pressurized portions and can be returned to a fuel tank or otherwise safely handled.
A component known as a boot is sometimes used in pressurized fuel systems and can assist in positioning and/or protecting certain components, including fuel injectors and fuel connections. An example boot employed in a fuel system is known from co-pending application Ser. No. 17/895,564, filed Aug. 25, 2022, to Wiebrecht. While the designs proposed in Wiebrecht offer promise, there is always room for improvement and development of alternative strategies.
In one aspect, a fuel system includes a fuel injector including an injector housing having a fuel inlet and a fuel outlet formed therein, and an electrical connector projecting from the injector housing. The fuel system further includes a fuel conduit connected to the fuel injector, and a boot positioned about the fuel injector and the fuel conduit. The boot includes a boot wall having a window formed therein receiving the electrical connector, and a filter attached to the boot wall. An air gap is defined between the fuel injector and the boot, and a filtered air flow path extends through the filter to the air gap.
In another aspect, a boot assembly for a fluid system includes an elongate boot body defining a longitudinal axis and including a boot wall extending circumferentially around the longitudinal axis and forming a central cavity extending axially between an open first axial end and an open second axial end. The boot wall has formed therein a window at a location axially between the open first axial end and the open second axial end, and an air opening at a location that is at least one of circumferentially offset or axially offset from the window. The boot assembly further includes a filter attached to the elongate boot body so as to form a filtered air flow path through the air opening into the central cavity.
In still another aspect, a boot for a fuel injector and fuel conduit assembly includes an elongate boot body defining a longitudinal axis and including a boot wall extending circumferentially around the longitudinal axis and forming a central cavity extending axially between an open first axial end and an open second axial end. The boot wall has formed therein a window at a location axially between the open first axial end and the open second axial end, and an air opening at a location that is at least one of circumferentially offset or axial offset from the window. The boot further includes a filter holder attached to the boot wall and positioned adjacent to the opening.
Referring to
Cylinder head 12 further includes one or more intake ports 20 formed therein. In a practical implementation engine system 10 is port-injected with liquid methanol fuel. The methanol fuel may be ignited by way of a compression-ignited direct injection of a diesel distillate fuel or ignited via dimethyl ether for example. As will be further apparent from the following description engine system 10 is uniquely configured by way of fuel system apparatus for containment of liquid fuel and fuel vapors as well as ventilation of fuel supply and containment apparatus. While aspects of the present disclosure are described in the context of a fuel system, in other instances teachings herein could be applied in a different type of fluid system, such as system supplying and delivering oil in an engine or other machinery context, or still other environments.
To this end, engine system 10 further includes a fuel system 22. Fuel system 22 includes a fuel injector and conduit assembly 24. Referring also now to
Fuel system 22 and assembly 24 further include a fuel conduit 36 connected to fuel injector 26. Fuel conduit 36 may include a double-walled fuel conduit having an outer wall 38 and an inner wall 40 defining a fuel supply passage 42 fluidly connected to fuel inlet 30, and also to a fuel pressurization pump and a liquid fuel supply such as a methanol fuel tank (not shown). An interwall space 44 typically having the form of an annulus is defined between outer wall 38 and inner wall 40. In a practical implementation strategy, a vacuum is drawn on interwall space 44 such that a negative pressure is continuously applied. In the event of fuel leakage the negative pressure can assist in ensuring that any leaked liquid fuel and/or vapors can be returned to a fuel tank, for example, or safely discharged to ambient. Inner wall 40 may further include an injector fitting 46 coupled to and in contact with a body portion 52 of fuel injector 26. A tip portion 54 of fuel injector 26 projects into fuel port 56. An O-ring 58 may be provided to seal between injector fitting 46 and body portion 52.
Assembly 24 further includes a boot 60. Boot 60 forms, together with fuel injector 26, a boot assembly 62. Boot 60 is positioned about fuel injector 26 and fuel conduit 36, and includes a boot wall 64. Referring also now to
Boot 60 further includes an elongate boot body 76. Boot 60 and boot body 76 are referred to, at times, interchangeably herein. Boot body 76 defines a longitudinal axis 78. Boot wall 80 includes an outer surface 77 and extends circumferentially around longitudinal axis 78 and forms a central cavity 82 extending axially between an open first axial end 84 and an open second axial end 86. A projecting annular flange is shown at 91 in
Referring also now to
Boot 60 may further include a filter holder 100. Filter holder 100 may include a pocket 102 with filter 68 received in pocket 102 and positioned across air opening 88. Filter 68 may be interference-fitted in filter holder 100. Also in the illustrated embodiment, filter holder 100 may be formed integrally with boot body 76, and formed on outer surface 77 of boot body 76.
Focusing on
Referring to the drawings generally, during service in engine system 10 filter 68 may accumulate debris that eventually reduces air flow into air gap 72 and limits a flow of air through interwall space 44. It may thus be desirable to swap out filter 68 at a periodic service interval, or when it is otherwise apparent that filter 68 should be changed such as after visual inspection. A user can grasp tab 104 and pull filter 68 out of filter holder 100, and install a replacement filter therein.
The present description is for illustrative purposes only, and should not be construed to narrow the breadth of the present disclosure in any way. Thus, those skilled in the art will appreciate that various modifications might be made to the presently disclosed embodiments without departing from the full and fair scope and spirit of the present disclosure. Other aspects, features and advantages will be apparent upon an examination of the attached drawings and appended claims. As used herein, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more.” Where only one item is intended, the term “one” or similar language is used. Also, as used herein, the terms “has,” “have,” “having,” or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.
