VALVE SEAT INSERT

Abstract

Embodiments may provide a valve seat insert including a valve seat face. A circumferential contact surface for contacting a cylinder head may be located radially outside and at least partially axially offset from the valve seat face. A discontinuity may be located radially between the valve seat face and the cylinder head and at least partially axially aligned with the valve seat face.

Description

FIELD

The present application relates to valve seat inserts.

BACKGROUND

Currently common engines can produce highly audible tick noises. The frequency range of the tick noise is often in the range of several hundred Hz to 15.0 kHz. The engine's valve train system, which typically includes a tappet, valve, valve coil spring, valve seat, and cam shaft(s) has been identified as a source of impact noises including valve closing impact between the valves and valve seats. Current valve seats have very high stiffness because of their geometry and their way of assembly so that the high frequency tick noises may be readily passed through to the cylinder head.

Valve seat inserts are often installed in cylinder heads to provide a seating surface and to receive the impact from the valves. They are typically annular shaped, and are forced or press-fitted into counterbores at respective mouths of intake, and/or exhaust passages. Valve seat inserts have been modified from the typical annular configuration in effort to provide some advantage to engine design, and/or operation. However, the inventors herein are not aware of any modifications that have been made to valve seat inserts for the purpose of reducing noise.

One example of valve seat insert modification is disclosed U.S. Pat. No. 6,260,531. The disclosure provides a valve seat insert for use in combination with a cylinder head, and includes several notches which cooperate with a surface within a counterbore in the cylinder head to form a plurality of passages or channels to allow fuel to freely pass between the surface and the insert. The channels are intended to substantially prevent fuel from becoming trapped between the insert and the counterbore, and to prevent formation of corrosive acids and byproducts.

The inventors herein have recognized several issues with this approach. For example, the approach fails to recognize valve seat inserts as a potential area within the engine to look for noise mitigation opportunities. What is needed is an approach which tends to isolate the impact, and consequent noise, produced by valves closing against valve seats while still maintaining enough strength and axial rigidity in the inserts.

Embodiments in accordance with the present disclosure may provide a valve seat insert including a valve seat face. A circumferential contact surface for contacting a cylinder head may be located radially outside and at least partially axially offset from the valve seat face. A discontinuity may be located radially between the valve seat face and the cylinder head and at least partially axially aligned with the valve seat face.

In this way the impact energy and vibration from the engine valves hitting the valve seat may tend to not reach the cylinder head, and the level of audible tick noises coming from the engine may be reduced. Some embodiment may provide a discontinuity in the form of a gap which may tend to make the radial stiffness of the seat area more flexible while still withstanding impact force from the valve. The flexibility may provide vibration isolation at certain frequencies, and may be particularly effective at providing high frequency isolation. The lower portion of valve seat may be configured such that the assembled strength and axial stiffness may provide robust strength and durability and may be used to hold the seat in position for press-fit assembly.

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.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an engine.

FIG. 2 is a detailed cross-sectional view of an example valve arrangement that may be used with the engine illustrated in FIG. 1 in accordance with the present disclosure.

FIG. 3 is an expanded cross-sectional view of a portion of the valve arrangement shown in FIG. 2 in accordance with the present disclosure.

FIG. 4 is an expanded cross-sectional view similar to FIG. 2 but illustrating another example valve arrangement in accordance with the present disclosure.

FIG. 5 is an expanded cross-sectional view illustrating yet another example valve arrangement in accordance with the present disclosure.

FIG. 6 is an expanded cross-sectional view illustrating another example valve arrangement in accordance with the present disclosure.

FIG. 7 is an expanded cross-sectional view illustrating another example valve arrangement in accordance with the present disclosure.

FIG. 8 is an expanded cross-sectional view illustrating another example valve arrangement in accordance with the present disclosure.

FIG. 9 is an expanded cross-sectional view illustrating another example valve arrangement in accordance with the present disclosure.

DETAILED DESCRIPTION

In one example, the application also relates to a valve seat insert for mitigating valve impact vibration transmission to the cylinder head by providing a discontinuity radially between the valve seat insert face and the cylinder head counter bore. Other additional or alternative examples includes a valve seat including indents on a surface edge facing a piston of an engine cylinder in a pattern around the periphery of the seat.

FIG. 1 is a schematic diagram showing one cylinder of multi-cylinder engine 10, which may be included in a propulsion system of an automobile. Engine 10 may be controlled at least partially by a control system including controller 12 and by input from a vehicle operator 132 via an input device 130. In this example, input device 130 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal PP. Combustion chamber (i.e. cylinder) 30 of engine 10 may include combustion chamber walls 32 with piston 36 positioned therein. Piston 36 may be coupled to crankshaft 40 so that reciprocating motion of the piston is translated into rotational motion of the crankshaft. Crankshaft 40 may be coupled to at least one drive wheel of a vehicle via an intermediate transmission system. Further, a starter motor may be coupled to crankshaft 40 via a flywheel to enable a starting operation of engine 10.

Combustion chamber 30 may receive intake air from intake manifold 44 via intake passage 42 and may exhaust combustion gases via exhaust passage 48. Intake manifold 44 and exhaust passage 48 can selectively communicate with combustion chamber 30 via respective intake valve 52 and exhaust valve 54. In some embodiments, combustion chamber 30 may include two or more intake valves and/or two or more exhaust valves.

Intake valve 52 may be controlled by controller 12 via electric valve actuator (EVA) 51. Similarly, exhaust valve 54 may be controlled by controller 12 via EVA 53. During some conditions, controller 12 may vary the signals provided to actuators 51 and 53 to control the opening and closing of the respective intake and exhaust valves. The position of intake valve 52 and exhaust valve 54 may be determined by valve position sensors 55 and 57, respectively, which indicate displacement of the valve along an axis of the actuator (see FIG. 2). As another example, cylinder 30 may include an intake valve controlled via electric valve actuation and an exhaust valve controlled via cam actuation including cam profile switching (CPS) and/or variable cam timing (VCT).

Fuel injector 66 is shown arranged in intake passage 44 in a configuration that provides what is known as port injection of fuel into the intake port upstream of combustion chamber 30. Fuel injector 66 may inject fuel in proportion to the pulse width of signal FPW received from controller 12 via electronic driver 68. Fuel may be delivered to fuel injector 66 by a fuel system (not shown) including a fuel tank, a fuel pump, and a fuel rail. In some embodiments, combustion chamber 30 may alternatively or additionally include a fuel injector coupled directly to combustion chamber 30 for injecting fuel directly therein, in a manner known as direct injection.

Intake passage 42 may include a throttle 62 having a throttle plate 64. In this particular example, the position of throttle plate 64 may be varied by controller 12 via a signal provided to an electric motor or actuator included with throttle 62, a configuration that is commonly referred to as electronic throttle control (ETC). In this manner, throttle 62 may be operated to vary the intake air provided to combustion chamber 30 among other engine cylinders. The position of throttle plate 64 may be provided to controller 12 by throttle position signal TP. Intake passage 42 may include a mass air flow sensor 120 and a manifold air pressure sensor 122 for providing respective signals MAF and MAP to controller 12.

Ignition system 88 can provide an ignition spark to combustion chamber 30 via spark plug 92 in response to spark advance signal SA from controller 12, under select operating modes. Exhaust gas sensor 126 is shown coupled to exhaust passage 48 upstream of emission control device 70. Sensor 126 may be any suitable sensor for providing an indication of exhaust gas air/fuel ratio such as a linear oxygen sensor or UEGO (universal or wide-range exhaust gas oxygen), a two-state oxygen sensor or EGO, a HEGO (heated EGO), a NOx, HC, or CO sensor. Emission control device 70 is shown arranged along exhaust passage 48 downstream of exhaust gas sensor 126. Device 70 may be a three way catalyst (TWC), NOx trap, various other emission control devices, or combinations thereof.

Controller 12 is shown in FIG. 1 as a microcomputer, including microprocessor unit 102, input/output ports 104, an electronic storage medium for executable programs and calibration values shown as read only memory chip 106 in this particular example, random access memory 108, keep alive memory 110, and a data bus. Controller 12 may receive various signals from sensors coupled to engine 10, in addition to those signals previously discussed, including measurement of inducted mass air flow (MAF) from mass air flow sensor 120; engine coolant temperature (ECT) from temperature sensor 112 coupled to cooling sleeve 114; a profile ignition pickup signal (PIP) from Hall effect sensor 118 (or other type) coupled to crankshaft 40; throttle position (TP) from a throttle position sensor; and absolute manifold pressure signal, MAP, from sensor 122. Engine speed signal, RPM, may be generated by controller 12 from signal PIP. Manifold pressure signal MAP from a manifold pressure sensor may be used to provide an indication of vacuum, or pressure, in the intake manifold. In one example, sensor 118, which is also used as an engine speed sensor, may produce a predetermined number of equally spaced pulses every revolution of the crankshaft thereby indicating crankshaft position.

Storage medium read-only memory 106 can be programmed with computer readable data representing instructions executable by processor 102 for performing the methods or routines described below as well as other variants that are anticipated but not specifically listed.

As described above, FIG. 1 shows only one cylinder of a multi-cylinder engine, and each cylinder may similarly include its own set of intake/exhaust valves, valve position sensor(s), fuel injector, spark plug, etc.

FIG. 2 is a detailed cross-sectional view of a valve arrangement 198 that may be, for example, an intake valve 52, or an exhaust valve 54 that may be used with the engine 10 illustrated in FIG. 1, or another engine. The valve illustrated in FIG. 2 may be referred to generally as valve 153. The valve 153 may be configured for movement within passage 155 to open and to close the passage 155 to respectively allow a fluid to pass through the passage 155, or to substantially prevent a fluid from passing through the passage 155, and into, or out of, the combustion chamber 30. The valve 153 is shown in a partially opened position. The passage 155 may be formed in, or coupled with, a cylinder head 157. The cylinder head 157 may sit above a cylinder block (not shown). The combustion chamber 30 may be formed at least partially in the cylinder block which may be closed at one end with the cylinder head 157. The passage 155 may include a counterbore 159 formed at a mouth of the passage 155.

FIG. 3 is an expanded view of a portion of the valve arrangement 198 shown in FIG. 2, and may be referred to in conjunction with FIG. 2. Various embodiments may include a valve seat insert 200 which may be positioned in the counterbore 159. The valve seat insert 200 may include a valve seat face 202, and a circumferential contact surface 204 for contacting the cylinder head 157. The contact surface 204 may be located radially outside the valve seat face 202, as illustrated with radially oriented arrow 208, and also located at least partially axially offset from the valve seat face 202, as illustrated with axially oriented arrow 210.

The valve seat insert 200 may also include a discontinuity 212 disposed radially between the valve seat face 202 and the cylinder head 157 and at least partially axially aligned with the valve seat face 202. The discontinuity 212 may make the radial stiffness of the valve seat area more flexible, or otherwise serve to isolate the valve seat face 202 from the cylinder head 157, when the valve 153 impacts the valve seat face 202. The valve 153 may contact the valve seat face 202 at a valve face 154. The flexibility, and/or the isolation, may serve to isolate various frequencies, for example high frequencies. In this way noise vibration and harshness that may be otherwise caused by repeated valve closures may be reduced, or eliminated.

In one example, the valve seat face 202 includes at least three surfaces angled with respect to one another, one perpendicular to the valve seat bore, and the others, one including the discontinuity, angled obliquely thereto, and angled oppositely with respect to one another. In one example, the surfaces of the valve seat face 202 may be annularly shaped and form adjacent rings with respect to one another when viewed from the direction of the piston.

In some cases the valve seat insert 200 may have a filleted edge 211. The filleted edge 211 may aid in inserting the valve seat insert 200 into the counterbore 159. Some example embodiments may not include a filleted edge 211. Some embodiments may include other surface features.

Various embodiments may provide a valve seat insert 200 that may include an outer surface 216 that may have a substantially cylindrical portion 218 configured to fit within and to make contact with the counterbore 159 within the cylinder head 157. The cylindrical portion 218 may be, or may substantially correspond with, the contact surface 204 described above. The outer surface 216 may also have a frusto-conical portion 220 configured to be spaced apart from the counterbore 159. This may accordingly form a discontinuity 212 radially between the valve seat face 202 and the counterbore 159.

There may be a center bore 222 through the valve seat insert 200. The valve seat face 202 may be formed in the center bore 222, and may be substantially axially aligned with the frusto-conical portion 220. The frusto-conical portion 220 may form a wedge shaped gap 214, or a gap 214 having a wedge shaped cross-section, between the outer surface 216 and the counterbore 159.

The valve seat insert 200 may include a central axis 224. The gap 214 may include a maximum radial thickness 226 of a predetermined amount. For example the maximum radial thickness 226 may be between approximately 0.1 mm and 1.0 mm. The frusto-conical portion 220 may include an edge 228 spaced from the substantially cylindrical portion 218 wherein the edge 228 is nominally located from an inner surface of the counterbore approximately 0.1 mm to 1.0 mm. In some embodiments the edge 228 may be nominally located from an inner surface 230 of the counterbore 159 approximately 0.3 mm.

In some embodiments the valve seat insert 202 may be made from, or include a flexible, or resilient material. In some embodiments the valve seat insert 202 may be made from, an elastomer. The valve seat insert 200 may be configured to deform when the valve seat face 202 is contacted by the valve 153. In some embodiments the gap 214 may be at least partially closed, or substantially closed, when the valve 153 makes forcible contact with the valve seat face 202. Further, the gap 214 may be contiguous with a side surface of the bore, ending at a location where the insert is in face-sharing contact with the bore.

In some embodiments, such as the one illustrated in FIG. 3, the discontinuity 212, may be a gap 214 that may be located adjacent to the inner surface 230 of the counterbore 159 in the cylinder head 157 as described above. In other example embodiments, the discontinuity 212 may be embodied differently. For example, FIG. 4 illustrates a valve seat insert 200 in accordance with the present disclosure wherein the discontinuity 212 may be a gap 314 spaced a distance from an inner surface 230 of the counterbore 159.

FIG. 5 illustrates another example embodiment in accordance with the present disclosure. The discontinuity 212 may be two or more gaps 414, for example two gaps 414 as illustrated.

FIG. 6 illustrates another example embodiment in accordance with the present disclosure. The majority of the valve seat insert 200 may be made from a first material and the discontinuity 212 may be made from a second material 514. In some cases the discontinuity 212 may be made from a material having a resilience, or flexibility, which may be different from the resilience, or flexibility of the majority of the material the valve seat insert 200 is made from. The difference in material, and/or the boundaries between the materials may provide an inefficient energy transmission mechanism. In this way, the energy from the valve 153 impacting the valve seat face 202 may be less effectively transmitted to the cylinder head 157.

FIG. 7 illustrates another example embodiment in accordance with the present disclosure. As illustrated, the discontinuity 212 may be an annular gap with a substantially rectangular cross-section 614.

FIG. 8 illustrates another example embodiment in accordance with the present disclosure. As illustrated, the discontinuity 212 may be, or may include, a portion of the frusto-conical portion 220 which extends beyond an outer circumferential edge 232 of the counterbore 159. In some embodiments the valve seat insert 200 may not include a frusto-conical portion 220, and the discontinuity 212 may be a cylindrical portion which may extend beyond an outer circumferential edge 232 of the counterbore 159.

Referring again in particular to FIGS. 2 and 3, some embodiments may provide a valve seat arrangement 300 which may include a counterbore 159 in a cylinder head 157 having an inner surface 230. A valve seat insert 200 may be fitted into the counterbore 159 and may have an outer surface 216. The outer surface 216 may include a first portion 218 contacting the counterbore inner surface 230, and a second portion 220 spaced from the counterbore inner surface 230. A valve seat face 202 may be radially inside the valve seat insert outer surface 216, and axially at least partially aligned with the valve seat insert second portion 220.

Referring to some of the other figures as well, in some embodiments the second portion 220 may form an annular notch 214, 314, 414, 614 between the outer surface 216 and the counterbore inner surface 230. The second portion 220 may form a wedge shaped notch between the outer surface 216 and the counterbore inner surface 230. The valve seat insert may be made from an elastomeric material.

FIG. 9 illustrates another example embodiment in accordance with the present disclosure. The example illustrates a valve seat arrangement that may be configured such that, when in an un-deformed state, the valve seat face 202 may be part of a curvilinear surface 902. In some cases the curvilinear surface 902 may extend beyond the valve seat face 20 and may meet the second portion 220 at an annular edge 940.

In any of FIGS. 2-9, inclusive, a gap, discontinuity, indent, etc., may extend continually around an entire circumference of the insert. In other examples, it may be divided in a repeating pattern around the annular surface facing the piston.

It should be understood that the arrangements, systems, and methods described herein are examples, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are contemplated. Accordingly, the present disclosure includes all novel and non-obvious combinations of the various arrangements, systems, and methods disclosed herein, as well as any and all equivalents thereof.

Claims

1. A valve seat insert, comprising:

a valve seat face;

a circumferential contact surface shaped to contact a cylinder head located radially outside the valve seat face; and

a gap radially between the valve seat face and the circumferential contact surface and at least partially axially aligned with the valve seat face, the gap centrally located along an annular outward surface that extends radially between the circumferential contact surface to the valve seat face.

2. The valve seat insert of claim 1, wherein the gap has a rectangular cross-section.

3. The valve seat insert of claim 2, wherein a valve seat insert material deforms when the valve seat face is contacted by a valve thereby at least partially closing the gap.

4. The valve seat insert of claim 2, wherein the gap is adjacent to an inner surface of a counterbore in the cylinder head.

5. The valve seat insert of claim 1, wherein the gap is an annular gap with a wedge shaped cross-section.

6. A valve seat insert, comprising:

an annular-shaped body, the body having a peripheral side-wall and an annular outward surface, the outward surface having at least an inwardly angled inner surface, and an outer surface perpendicular to a central axis of the body, the outer surface including a gap that is spaced away and does not intersect the inwardly angled inner surface, and which is axially aligned with a valve seat face.

7. The valve seat insert of claim 6 wherein the gap has a cross-section of an arch.

8. The valve seat insert of claim 6 wherein the gap forms an indent having a rectangular cross-section in the outer surface.

9. The valve seat insert of claim 8 wherein the indent traverses completely around the outer surface around the central axis of the body.

10. A valve seat insert, comprising:

an outer surface having a substantially cylindrical portion configured to fit within and to make contact with a counterbore within a cylinder head and a frusto-conical portion configured to be spaced apart from the counterbore, the frusto-conical portion positioned between a gap and the outer surface.

11. The valve seat insert of claim 10, further comprising a center bore through the insert, and a valve seat face formed in the center bore substantially axially aligned with the frusto-conical portion.

12. The valve seat insert of claim 10, wherein the frusto-conical portion forms a wedge shaped gap between the outer surface and the counterbore.

13. The valve seat insert of claim 12, wherein the valve seat insert includes a central axis and wherein the gap includes a maximum radial thickness of between approximately 0.1 mm and 1.0 mm.

14. The valve seat insert of claim 10, wherein the frusto-conical portion includes an edge spaced from the substantially cylindrical portion wherein the edge is nominally located from an inner surface of the counterbore approximately 0.1 mm to 1.0 mm.

15. The valve seat insert of claim 10, wherein the frusto-conical portion includes an edge spaced from the substantially cylindrical portion wherein the edge is nominally located from an inner surface of the counterbore approximately 0.3 mm.

16. The valve seat insert of claim 10, wherein the gap is substantially closed when a valve makes forcible contact with a valve seat, and wherein valve seat insert is an elastomer.

17. (canceled)

18. A valve seat arrangement comprising:

a counterbore in a cylinder head having an inner surface;

a valve seat insert fitted into the counterbore having an outer surface, the outer surface including: a first portion contacting the counterbore inner surface, and a second portion spaced from the counterbore inner surface; and

a valve seat face radially inside the valve seat insert outer surface, and axially at least partially aligned with the valve seat insert second portion; and

a gap located along a surface extending from the valve seat face to the second portion spaced from the counterbore inner surface.

19. The valve seat arrangement of claim 18, wherein when in an un-deformed state the valve seat face is part of a curvilinear surface extending beyond the valve seat face which meets the second portion at an annular edge.

20. The valve seat arrangement of claim 18, wherein at least one or more of the following structures are present: the second portion forms an annular notch between the outer surface and the counterbore inner surface, the second portion forms a wedge shaped notch between the outer surface and the counterbore inner surface, and the valve seat insert is made from an elastomeric material.