Patent Application
20120060792
The present application relates to a bevel isolator for attenuating noise caused by impact between a direct injector tip and a cylinder head in a direct injection engine of a vehicle.
Vehicles with direct injection engines typically include a fuel rail for delivery of pressurized fuel to a plurality of injectors, wherein each of the injectors is coupled to a cylinder head for direct injection of fuel into an engine cylinder. Due to high operating fuel pressure and direct coupling of injectors to cylinder heads, undesirable structureborne noise may be generated during idle operation of the vehicle. High frequency energy may be transmitted from the injector to the cylinder head. Specifically, a “ticking” noise may be generated because of high frequency energy caused by impact between the magnetic solenoid valve armature and stopper at injector opening, and pin and seat at injector closing. This noise may be audible to an operator when the engine is at idle, and produces little background noise.
In one approach, described in US Patent Application Publication US2009/0071445, a steel dampening element is disposed between a conical region of injection valve and a cylinder head. The dampening element has a conical shape and a central pass through wherein the injector is fitted. A top portion of the dampening element includes an elevation, such as an annular flange, which abuts the injector. A diameter of the dampening element is less than a diameter of the cylinder head, such that a first gap is exists between the support element and the cylinder head. A second gap exists between a lower portion of the support element and the injector, below a line of contact/abutment between the injector and the annular flange. A force from the injector may bend the top portion of the dampening element outward generating radial displacement into the first gap in order to absorb a portion of the impact. Thus, during operation of the vehicle, periodic pulses of the injector are transferred to the cylinder head in an attenuated fashion.
The inventors herein recognize potential issues with such a configuration for a dampening element. As one example, an outer wall of the top portion of the previously described dampening element may impact an inner wall of the cylinder head at a specific line of contact during radial displacement. In cases where the cylinder head is comprised of aluminum, the steel dampening element may damage the inner wall of the cylinder head over time. In another example, much of the elastic deformation of the previously described dampening element may be absorbed at a joint between the upper portion and a lower portion. In this example, the joint may be weakened over time and may eventually be deformed or broken.
Thus, some of the above issues may be at least partly addressed by a direct fuel injection cylinder of an engine, comprising, a cylinder head including an injector bore with a shelf; a high-pressure direct injector disposed in the injector bore; and a spring washer disposed between the high-pressure direct injector and the shelf with the high-pressure direct injector positioned through a central pass-through of the spring washer, the spring washer forming a conical wall with a plurality of waves.
In this example, the spring washer includes a series of regular waves, and inner-facing troughs of the waves contact the injector in the non-compressed state. In order to absorb impact of the injector, each of the waves may be elastically deformed from the non-compressed state into the compressed state. Therefore, elastic deformation is distributed over a larger surface area than that of the previously described dampening element. In the compressed state, outer-facing crests of the waves may contact the cylinder head. Impact of the spring washer against the wall of the cylinder head is distributed over a larger surface area and may decrease damage to the inner wall of the cylinder head. Further, the cone may be elastically deformed by the introduction of hoop stress. As such, an angle at the intersection of an inner side of the spring washer and the shelf in the injector bore has first magnitude in the non-compressed state and a second magnitude in the compressed state. In this example, the first magnitude is less than the second magnitude.
In one specific example, a spring washer includes a conical wall encompassing a central pass-through, the conical wall comprising a plurality of regular waves. In this example, the waves are beveled such that a crest of a wave and a trough of a wave are substantially flat. The crests and the troughs are joined via connecting walls. The connecting walls intersect each of the crests and troughs at an equal angle, and the angle may be greater in the compressed state than the non-compressed state. As such, during operation of the direct injection fuel system, elastic deformation is absorbed by the dampening element at each of the lines of intersection between the angled flat portions and each of the crests and troughs. Further, the cone may absorb impact via hoop stress.
Combined these features provide a spring washer which distributes elastic deformation over a greater surface area, and therefore the spring washer may have increased durability. Additionally, impact of the spring washer against the surface of the cylinder head is distributed over a larger surface area, and therefore over time the spring washer may limit damage to the surface of the cylinder head.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
The following description relates to a direct injection fuel cylinder for an engine of a vehicle, such as a direct injection gasoline engine.
An example embodiment of a dampening element is a spring washer, the location of which is shown in
As depicted in
Further, in the embodiment of
A booster port 20 and a scavenging port 24 are coupled to the combustion chamber 18 and may introduce fresh air including lubrication oil to the combustion chamber 18. Also, an exhaust port 22 is coupled to the combustion chamber 18 for discharging exhaust gas therethrough. The exhaust port 22 is provided on a side of the combustion chamber 18 opposing the booster port 20, while the scavenging port 24 is provided therebetween.
Opening and closing of each of the booster port 20, the scavenging port 24, and the exhaust port 22 is regulated by the reciprocating motion of a piston 26. As the piston 26 moves up, the ports are closed. As the piston 26 moves down, the ports are opened. Movement of the piston 26 is actuated by a crank shaft (not shown). Additionally, the piston 26 forms the bottom of the combustion chamber 18.
A spark plug 28 is at least partially disposed in a spark plug bore 30 within the cylinder head 14. The spark plug bore 30 is located at a side of combustion chamber 18, proximal to the exhaust port 22. The spark plug bore 30 is angled through the cylinder head 14 and an electrode 34 of the spark plug 28 is exposed in the combustion chamber 18. The spark plug 28 may ignite fuel spray so that the fuel may be burned in the combustion chamber 18. Accordingly, an injector 32 is provided proximal to the spark plug 28.
The injector 32 is a component of a high pressure fuel system. The high pressure fuel system may additionally include a lift pump (not shown), a high pressure pump (not shown), and a fuel rail (not shown). The lift pump may draw fuel from a fuel supply (not shown) and fuel may be pressurized by the high pressure pump. Fuel may be delivered to the injector via the fuel rail coupled to an outlet of the high pressure fuel pump.
The injector 32 is at least partially disposed in an injector bore 36. The injector bore 36 includes a lower shelf 44, wherein a lower shoulder 42 of the injector 32 may be abutted. Additionally, the injector bore 36 includes an upper shelf 40, wherein an upper shoulder 38 of the injector may be abutted. Both of these interfaces may provide a support surface so that the injector 32 may not move further into the combustion chamber 18. During operation of the engine 10, pressurized fuel enters the injector 32 from the fuel rail (not shown). The high pressure flow of fuel may cause the injector to impact the cylinder head at the locations of the lower shelf 44 and the lower shoulder 42, and the upper shelf 40 and upper shoulder 38. Noise generation may be attenuated by including a dampening element within the injector bore 36, such as a conical wave washer. An example embodiment of a conical wave washer 104 is shown in
The outer housing 106 has a diameter D1, the actuator 108 and a top face 116 of the conical portion 110 have a diameter D2, a bottom face 118 of the conical portion 110 has a diameter D3, and the nozzle 112 has a diameter D4. Diameter D2 is greater than diameter D3, such that an angled wall 114 of the conical portion 110 is formed between the actuator 108 and the bottom face of the conical portion 110. The diameter D3 is greater than diameter D4, such that the lower shoulder 42 is formed between the nozzle 112 and the bottom face 118 of the conical portion 110. Thus, a radial length A of the lower shoulder 42 is equal to the difference between diameter D3 and diameter D4.
As stated above, the outer housing 106 of the actuator 108 has the diameter D1. Diameter D1 is greater than diameter D2, and the upper shoulder 38 is formed where the outer housing 106 stops on the main body of the actuator 108. Thus, a radial length B of the upper shoulder 38 is equal to the difference between diameter D1 and diameter D2.
The injector bore 36 is complementary in shape and size to the injector 32. As such, the injector bore 36 has a generally stepped configuration. The outer housing 106 may be fitted into an upper portion 120, which is the widest portion of the injector bore 36. The upper portion 120 substantially has the diameter D1. The actuator 108, where it is not covered by the outer housing 106, may be fitted into a mid portion 122 of the injector bore 36. The mid portion 122 substantially has the diameter D2. As above, diameter D2 is less than diameter D1, such that the upper shelf 40 is formed at the intersection of the upper portion 120 and the mid portion 122. Thus, the upper shelf 40 substantially has the radial distance B which is equal to the difference between diameter D1 and diameter D2. The nozzle 112 may be fitted into a lower portion 124, which is the narrowest portion of the injector bore 36. The lower portion 124 substantially has the diameter D4.
An angled wall 128 is included in the mid portion 122, proximal to the lower portion 124. The conical portion 110 of injector 32 may be fitted into the mid portion 122 at the location of the angled wall 128. A bottom of the mid portion 122, at lower shelf 44, has a diameter D5. Diameter D5 is less than diameter D2 and greater than diameter D4. Thus, the width of the mid portion 122 narrows at the location of the angled wall 128, and the lower shelf 44 is formed at an intersection of the mid portion 122 and the lower portion 124. The lower shelf 44 has a radial distance D, which is equal to the difference between diameter D5 and diameter D2.
A conical wave washer 130 is disposed between the conical portion 110 of the injector 32 and the angled wall 128 of the injector bore 36. The conical wave washer 130 may be comprised of steel or another desired metallic material. Further, in some embodiments, the conical wave washer may be comprised of plastic. A top edge 234 (shown in
The conical wave washer 130 is shown in the non-compressed state in
As depicted in
Each of the adjacent crests and troughs are joined by a connecting wall, such as a connecting wall 240. The connecting wall 240 is extended between adjacent ends of the crest 230 and the trough 220, and intersects each of the crest 230 and the trough 220 at an angle α1. In alternate embodiments, the angle of intersection between the crest and the connecting wall may vary from the angle of intersection between the connecting wall and the trough.
In the present embodiment, the crest 230 and the trough 220 have a width G (a 1:1 ratio), while the connecting wall 240 has a width H. Width H is approximately two times width G (a 2:1 ratio). In alternate embodiments, the ratio between widths of the crests and troughs may vary. Further, the ratio between the crests and/or the troughs and the connecting walls may vary. For example, the troughs may have a width that is approximately one half the width of the crests (a 2:1 ratio), while the angled walls are the same width as the crests (a 1:1 ratio).
A wave 250, has a wavelength K1 and an amplitude J1. The wavelength K1 and the amplitude J1 are both dependent on the widths of the crests and troughs and the degree of the angle α1. In alternate embodiments, if widths G and H are increased and/or if the angle α1 is increased, then the wavelength K1 may be increased. In other alternate embodiments, if the widths G and H are decreased and/or if the angle α1 is decreased, then the overall the wavelength K1 may be decreased. Further, if the width H is increased and/or the angle α1 is decreased, then the amplitude J1 may be increased. Further still, if the width H is decreased and/or the angle α1 is increased, then the amplitude J1 may be decreased.
As depicted in
Each of the crests, the troughs, and the connecting walls has a length L. The conical wave washer 130 has an overall height N1. The overall height N1 is dependent on the length L and a magnitude of an angle of intersection, an angle β1. As such, the angle β1 includes an angle between the bottom edge 232 and the lower shelf 44. In alternate embodiments, if length L is increased and/or if the angle β1 is decreased, then the overall height N1 may be increased. In other alternate embodiments, if the length L is decreased and/or if the angle β1 is increased, then the overall height N1 may be decreased.
During operation of the vehicle, high pressure fuel may be injected through the injector and into the combustion chamber. High frequency energy may be generated from the direct injection process and cause the injector to transmit high frequency energy. In an embodiment wherein the direct injector excludes a dampening element, the injector actuator may impact the lower shelf and/or the upper shelf of the injector bore within the cylinder head. At idle conditions, background noise from the engine is low, therefore the impact may be noticeable to an operator, as an undesirable ticking noise. In the present embodiment, the conical wave washer 130 may attenuate the ticking noise to a desirable noise level.
The conical wave washer 130 may attenuate noise via absorbing the high frequency energy. The high frequency energy may be absorbed by hoop stress of the cone and elastic deformation of the waves as the conical wave washer moves from a non-compressed state to a compressed state. In both cases, the conical wave washer is radially displaced. By introduction of hoop stress to the conical wave washer 130 in the compressed configuration, the angle β1 may increase while the overall height N1 decreases. Additionally, during elastic deformation of the waves, the angle α1 and the wavelength K1 may increase while the amplitude J1 is decreased in the compressed state. In the compressed state, the injector 32 may be further disposed within the conical wave washer 130 than is shown in the non-compressed state of
An example embodiment of the conical wave washer 130 in the compressed state is shown in
Further, an overall height N2 of the conical wave washer in the compressed configuration is less than the overall height N1 of the conical wave washer in the non-compressed configuration. Similarly, the amplitude J2 of the conical wave washer in the compressed state is less than the amplitude J1 of the conical wave washer in the non-compressed state. Furthermore, a wavelength K2 of the example wave 250 in the compressed state is greater than the wavelength of the wave 250 in the non-compressed state.
Further still, each of diameters D9b and D10b may increase to a distance greater than diameters D9a and D10b, respectively. The difference between diameter D9b and D9a (ΔD9) may be a result of radial expansion of the beveled waves in the compressed state. The difference between diameter D10b and D10a (ΔD10) may be a result of radial expansion to the beveled waves and/or hoop stress introduced to the cone. Therefore, in the present embodiment, ΔD10 may be greater than ΔD9.
In the present embodiment, as stated above and shown in
The above description characterizes a dampening element for a direct injection fuel injector of a vehicle. The dampening element is a conical wave washer. Use of a conical wave washer in direct injection noise attenuation may have the advantages of having a greater surface area for contacting the injector and the cylinder head and having greater distribution of elastic deformation over previously described dampening elements. These features of a conical wave washer contribute to the dampening element causing decreased damage to the cylinder head and increasing the durability of the dampening element.
It will be appreciated that the configurations disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above technology can be applied to various types of vehicles, such as cars or trucks. In another example, the technology can be applied to hybrid vehicle or a combustion engine only vehicle. Further, the technology can be applied to stationary engines. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.
The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.
