Patent Application
20240344700
This disclosure relates generally to an internal combustion engine and, more particularly, to an ignition system for the engine.
An internal combustion engine includes an ignition system for igniting a fuel-air mixture for combustion. Various types and configurations of ignition systems are known in the art. While these known ignition systems have various benefits, there is still room in the art for improvement.
According to an aspect of the present disclosure, an assembly is provided for a powerplant. This assembly includes a housing, a primary fuel injector and an ignition system. The housing forms a combustion volume within the housing. The primary fuel injector is configured to inject primary fuel into the combustion volume. The ignition system is configured to ignite the primary fuel within the combustion volume. The ignition system includes a pilot fuel injector, a pilot ignitor, a pilot chamber, a first component and a second component. The pilot fuel injector is configured to inject pilot fuel into the pilot chamber. The pilot ignitor is configured to ignite the pilot fuel within the pilot chamber. The pilot chamber is fluidly coupled with the combustion volume through an aperture in the first component. The pilot chamber is formed by and disposed between the first component and the second component. The first component is configured from or otherwise include a ceramic.
According to another aspect of the present disclosure, another assembly is provided for a powerplant. This assembly includes a housing, a first component, a second component, a fuel injector and an ignitor. The housing forms a combustion volume within the housing. The first component includes a cavity, a receptacle and an aperture. The cavity forms at least a portion of a chamber within the first component. The receptacle extends longitudinally into the first component to the cavity. The aperture fluidly couples the chamber to the combustion volume. The first component is configured from or otherwise includes a ceramic. The second component projects longitudinally into the receptacle to the chamber. The fuel injector is configured to inject fuel into the chamber. The ignitor is configured to ignite the fuel within the chamber.
According to still another aspect of the present disclosure, another assembly is provided for a powerplant. This assembly includes a housing, a chamber module, a fuel injector and an ignitor. The housing forms a combustion volume within the housing. The chamber module is fastened to the housing. The chamber module includes a first component, a second component, a support ring and a chamber. The first component is clamped between the second component and the support ring. The first component projects through a receptacle in the housing to the combustion volume. The second component is secured to the support ring through a threaded interface between the second component and the support ring. The chamber is formed by and between the first component and the second component. The chamber is fluidly coupled to the combustion volume through an aperture in the first component. The fuel injector is configured to inject fuel into the chamber. The ignitor is configured to ignite the fuel within the chamber.
The second component may be configured from or otherwise include a metal.
The pilot chamber may have a spherical geometry.
A majority of a volume of the pilot chamber may be formed within the first component.
The first component may extend longitudinally along a centerline towards the combustion volume. A portion of the pilot chamber may extend laterally into and longitudinally within a sidewall of the first component.
The first component may include a cavity and a receptacle. The cavity may form at least a portion of the pilot chamber within the first component. The receptacle may extend longitudinally into the first component to the cavity. The second component may project longitudinally into the receptacle to the pilot chamber.
The second component may include a recess at a distal end of the second component. The recess may form a portion of the pilot chamber within the second component.
The cavity may have a lateral cavity width. The receptacle may have a lateral receptacle width at a longitudinal interface between the receptacle and the cavity. The lateral receptacle width may be smaller than the lateral cavity width.
A second receptacle may extend longitudinally into the housing from an exterior of the housing to the combustion volume. The first component may be disposed within the second receptacle and project longitudinally to the combustion volume.
The assembly may also include a cover secured to the housing and enclosing the first component and the second component within the second receptacle.
The second component may be fastened to the housing by one or more fasteners. The first component may be clamped between the second component and the housing.
The assembly may also include a first seal element and/or a second seal element. The first seal element may be engaged with and between the first component and the housing. The second seal element may be engaged with and between the first component and the second component.
The assembly may also include a pilot chamber module. The pilot chamber module may include the first component, the second component and a support ring. The second component may be fastened to the support ring. The first component may be clamped between the second component and the support ring.
The second component may be threaded into the support ring.
The assembly may also include a first seal element and/or a second seal element. The first seal element may be engaged with and between the support ring and the housing. The second seal element may be engaged with and between the second component and the support ring.
The assembly includes a cover over the pilot chamber module. The cover is fastened to the housing by one or more fasteners. The pilot chamber module is clamped between the cover and the housing.
The pilot fuel injector may be configured to inject the pilot fuel into the pilot chamber through a fuel aperture in the first component. In addition or alternatively, the pilot ignitor may be received in an ignitor aperture in the first component.
The assembly may also include a rotary engine that includes the housing, the primary fuel injector and the ignition system.
The present disclosure may include any one or more of the individual features disclosed above and/or below alone or in any combination thereof.
The foregoing features and the operation of the invention will become more apparent in light of the following description and the accompanying drawings.
The mechanical load 22 may be configured as or otherwise include a rotor 28 mechanically driven by the engine 26 through the drivetrain 24. This driven rotor 28 may be a bladed propulsor rotor where the powerplant 20 is configured as or otherwise includes a propulsion system for the aircraft. The propulsor rotor may be an open (e.g., un-ducted) rotor for the aircraft such as, but not limited to, a propeller rotor or a rotorcraft rotor (e.g., a main helicopter rotor). Alternatively, the propulsor rotor may be a ducted rotor for the aircraft such as, but not limited to, a fan rotor. Still alternatively, the driven rotor 28 may be a generator rotor in an electrical power generator where the powerplant 20 is configured as or otherwise includes an auxiliary power unit (APU) for the aircraft. The present disclosure, however, is not limited to the foregoing exemplary driven rotor configurations. Furthermore, the present disclosure is not limited to aircraft applications. The powerplant 20, for example, may alternatively be configured as a ground-based electrical generator or a powerplant for a ground vehicle.
The drivetrain 24 may be configured as a direct-drive drivetrain. With such a configuration, the driven rotor 28 is operable to rotate at a common (the same) rotational speed as a rotating structure 30 of the engine 26. Alternatively, the drivetrain 24 may be configured as a geared drivetrain. With such a configuration, the drive rotor is operable to rotate as a different (e.g., fastener or slower) rotational speed than the rotating structure 30. The drivetrain 24, for example, may include a geartrain 32 and/or another transmission device coupled between the driven rotor 28 and the rotating structure 30.
The engine 26 may be configured as a rotary engine such as, but not limited to, a Wankel engine. The engine 26 of
The housing 34 of
The rotor 36 of
The rotor 36 may have a non-circular, lobed cross-sectional geometry when viewed, for example, in a reference plane perpendicular to the rotor centerline 54. The rotor 36 of
The rotor 36 and the housing 34 may collectively form one or more combustion volumes 66A-C (generally referred to as “66”) (e.g., combustion chambers, working volumes, etc.) within the housing 34. Each combustion volume 66, in particular, is formed by and between a respective one of the rotor faces 58 and a corresponding (albeit changing) portion of the housing sidewall 50, and circumferentially between a respective neighboring pair of the rotor seals 62. Each of the combustion volumes 66 moves about the centerline 54, 56 as the rotor 36 eccentrically rotates within the housing 34 and its housing cavity 42. With the rotor position of
The primary fuel injector 38 is mated with/received within the primary fuel injector receptacle 44. The primary fuel injector 38, for example, projects into the primary fuel injector receptacle 44 and is threaded into or otherwise attached to the housing 34.
The ignition system 40 is attached to the housing 34 as described below in further detail.
During engine operation, air is directed through the intake passage 46 into a respective one of the combustion volumes 66. As the rotor 36 rotates within the housing 34, a volumetric measure of the respective combustion volume 66 decreases thereby compressing the air within that combustion volume 66. The primary fuel injector 38 directs (e.g., injects) primary fuel into the respective combustion volume 66 to mix with the air as it is being compressed to provide a fuel-air mixture. When the respective combustion volume 66 aligns with the ignition system 40, the fuel-air mixture within that combustion volume 66 is ignited to generate combustion products. As the rotor 36 continues to rotate within the housing 34, the volumetric measure of the respective combustion volume 66 increases thereby facilitating expansion of the combustion products within the respective combustion volume 66 until those expanded combustion products are exhausted from the engine 26 through the exhaust passage 48. The expansion of the combustion products within the respective combustion volume 66 drives rotation of the rotor 36 within the housing 34. The rotation of the rotor 36 and, thus, the rotation of the rotating structure 30 in turn drives rotation of the driven rotor 28 of
Referring to
The combustion of the pilot fuel within the pilot chamber 74 may be continuous (e.g., sustained) throughout an engine cycle. Here, the term “engine cycle” may describe a cycle as the rotor 36 makes a complete rotation about the rotor centerline 54 within the housing 34. The continuous combustion within the pilot chamber 74 may subject the pilot structure 68 to relatively high thermal loads, particularly a portion of the pilot chamber 74 adjacent and partially forming the respective combustion volume 66. Such high thermal loads may cause relatively high compressive stresses within the pilot structure 68 which may affect pilot structure durability. Moreover, the high thermal loads paired with a relatively high velocity fluid flow associated with directing the flame and/or the combustion products through the pilot aperture 76 into the respective combustion volume 66 may erode material of the pilot structure 68 forming the pilot aperture 76.
To increase pilot structure durability, the pilot structure 68 may be manufactured from ceramic such as, but not limited to, SiN or SiC ceramic material. However, casting or sintering a single monolithic ceramic body with an embedded chamber may be difficult. Furthermore, even where a single monolithic ceramic body with an embedded chamber can be formed, it may be difficult to finish surface(s) forming the embedded chamber due to minimal (if any) tool access into the chamber. Therefore, referring to
Referring to
The first base 88 projects longitudinally along the longitudinal centerline 82 from the first component outer end 84 to the first component inner end 86. The first base 88 includes an internal chamber cavity 92, a second component receptacle 94 and the pilot aperture 76.
The chamber cavity 92 is disposed (e.g., completely) within the first base 88 proximate the first component inner end 86, and longitudinally between the second component receptacle 94 and the pilot aperture 76. The second component receptacle 94 projects longitudinally along the longitudinal centerline 82 into the first base 88 from the first component outer end 84 to the chamber cavity 92. The second component receptacle 94 may be cylindrical with a uniform (e.g., constant) lateral receptacle width 96 (e.g., diameter) along its longitudinal length. A lateral cavity width 98 of the chamber cavity 92, on the other hand, may change along its longitudinal length. The lateral cavity width 98 may have a (e.g., maximum) value that is larger than a value of the lateral receptacle width 96 at a longitudinal interface between the chamber cavity 92 and the second component receptacle 94. With this arrangement, a (e.g., annular) portion 97 of the chamber cavity 92 extends partially laterally (e.g., radially) into and longitudinally within a sidewall 100 of the first component 78 and its first base 88. A portion of the first base 88 and its first sidewall 100 at the interface may thereby partially laterally overhang the chamber cavity 92.
The pilot aperture 76 extends through an endwall 102 of the first component 78 and its first base 88 from the chamber cavity 92 to the first component inner end 86. A centerline of the pilot aperture 76 may be angularly offset from the longitudinal centerline 82 by a non-zero acute angle. The present disclosure, however, is not limited to such an exemplary angularly offset pilot aperture arrangement.
The first base 88 may also include a fuel aperture 104 and at least one ignitor aperture 106. Each of these apertures 104, 106 extends through the first sidewall 100 to the chamber cavity 92. The fuel aperture 104 and the ignitor aperture 106 may be disposed on opposing lateral sides of the chamber cavity 92.
The first mount 90 is disposed at the first component outer end 84. The first mount 90 extends circumferentially about (e.g., completely around) the first base 88. The first mount 90 projects laterally out from the first base 88 to a lateral outer periphery of the first mount 90. Referring to
Referring to
Referring to
The second base 116 projects longitudinally along the longitudinal centerline 82 from the second component outer end 112 to the second component inner end 114. The second base 116 includes a chamber recess 120 at the second component inner end 114. This chamber recess 120 extends partially longitudinally into the second base 116 from the second component inner end 114. The second base 116 may also include a (e.g., weight-reduction) bore 122 at the first component inner end 86. This bore 122 extends partially longitudinally into the second base 116 from the second component outer end 112, where an endwall 124 of the second base 116 may completely separate the bore 122 from the chamber recess 120.
The second mount 118 is disposed at the second component outer end 112. The second mount 118 extends circumferentially about (e.g., completely around) the second base 116. The second mount 118 projects laterally out from the second base 116 to a lateral outer periphery of the second mount 118. Referring to
Referring to
Referring to
The entire second component 80 may also be disposed within the pilot structure receptacle 130. The second component 80 is mated with (e.g., plugged into) the first component 78 and its second component receptacle 94. The second base 116, for example, projects longitudinally through the second component receptacle 94 to the chamber cavity 92. The second mount 118 is seated longitudinally against the first mount 90 within the pilot structure receptacle 130. A second seal element 136 (e.g., a ring seal element) may be disposed longitudinally between and engage (e.g., contact) the first mount 90 and the second mount 118. The second component 80 and its second mount 118 may be mechanically fastened to the housing 34 using one or more fasteners 138; e.g., bolts. Each bolt 138, for example, may extend sequentially through a respective one of the second fastener apertures 126 (see
With the above pilot structure arrangement, the pilot chamber 74 is formed by and longitudinally between the first component 78 and the second component 80 within the pilot structure 68. In particular, the chamber cavity 92 forms a first portion of the pilot chamber 74 and the chamber recess 120 forms a second portion of the pilot chamber 74. However, while both the first component 78 and the second component 80 collectively form the pilot chamber 74, the first component 78 and its chamber cavity 92 may be configured to form a majority (more than fifty percent) of a volume of the pilot chamber 74; e.g., more than sixty percent (60%), seventy percent (70%) or even eighty percent (80%) of the pilot chamber 74. Note, the greater the percentage of the pilot chamber 74 formed by the first component 78, the greater percentage of the pilot chamber 74 formed by the ceramic material where, for example, the second component 80 is formed from metal.
The pilot chamber 74 of
The pilot injector 70 of
To shield the pilot structure 68 from an environment and/or other components outside of the engine 26 and its housing 34, a cover 140 (e.g., a cover plate) is secured to the housing 34. The cover 140 covers (e.g., blocks, overlaps, etc.) an opening to the pilot structure receptacle 130 into the housing 34. The cover 140 may thereby enclose the pilot structure 68 and its components (e.g., 78 and 80) within the housing 34 and its pilot structure receptacle 130. The cover 140 of
The pilot structure 68 of
In some embodiments, referring to
To seal the pilot structure 68, the first seal element 134 of
In the embodiment of
While the first component 78 is described above as being formed from ceramic, the present disclosure is not limited to such an exemplary construction. It is contemplated, for example, the first component 78 may alternatively be formed from metal (or another high temperature material) where, for example, the cavity surface 110 is coated with a thermal barrier layer.
The ignition system 40 is described above with reference to the rotary engine; e.g., the Wankel engine. It is contemplated, however, the ignition system 40 may alternatively be configured with various other types of engines such as a reciprocating piston engine or a gas turbine engine. The present disclosure therefore is not limited to any particular engine types or configurations.
While various embodiments of the present disclosure have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the disclosure. For example, the present disclosure as described herein includes several aspects and embodiments that include particular features. Although these features may be described individually, it is within the scope of the present disclosure that some or all of these features may be combined with any one of the aspects and remain within the scope of the disclosure. Accordingly, the present disclosure is not to be restricted except in light of the attached claims and their equivalents.
