Internal combustion engine valve guards

Abstract

The present invention relates to a valve guard for an internal combustion engine. An engine is provided, the engine having a cylinder head and a valve guide, the cylinder head defining a lubrication passage intersecting with a bore wall of the valve guide. The valve guide has an inner wall and an outer wall intersecting with a valve side end and a port side end. The inner wall defines a channel extending from a middle region of the guide to the valve side end. The guide defines a passage extending outwardly from the passage to the outer wall at the middle region, wherein the passage is fluidically connected to the lubrication passage. A pressurized lubricant is provided to the lubrication passage intersecting with a bore wall of the valve guide of the cylinder head. The lubricant is introduced from the lubrication passage into the passage, which extends in the middle region of the valve guide. A moving valve stem located in the guide is lubricated by causing the lubricant to flow from the passage into the passage intersecting with the inner wall of the guide and to flow to the valve end of the guide.

Description

Technical Field

[0001] Various embodiments relate to valves and valve guards in a cylinder head of an internal combustion engine. Background Art

[0002] Internal combustion engines (including four-stroke engines) use valves to control the flow of intake gases (e.g., air or a fuel-air mixture) from the intake manifold into the cylinders, and use valves to control the flow of exhaust gases from the cylinders to the exhaust manifold. Typically, the valves are configured as poppet valves, wherein each valve includes a valve stem extending to a valve head. The valve guide is configured to accurately position the valve relative to the valve seat, help seal the intake manifold or the exhaust manifold, and provide thermal protection for the valve. The valve stem extends through the valve guide and moves relative to the valve guide as a running surface, and in conventional valves, the interface between the valve guide and the running surface of the valve stem is non-lubricated. As the engine operates and over time, the valve guide may experience wear, deformation, and reduced mechanical performance because the interface between the valve stem and the valve guide may generate friction and heat. Summary of the invention

[0003] In an embodiment, an engine is provided, the engine having a cylinder head and a valve guide, the cylinder head defining a lubrication passage intersecting with a valve guide bore wall. The valve guide has an inner wall and an outer wall intersecting with a valve-side end and a port-side end. The inner wall defines a passage extending from a middle region of the guide to the valve-side end. The guide defines a passage extending outwardly from the passage to the outer wall at the middle region, wherein the passage is fluidly connected to the lubrication passage.

[0004] According to one embodiment of the invention, the engine further comprises a pump, which is fluidly connected to the lubrication passage and provides pressurized lubricant to the lubrication passage.

[0005] According to one embodiment of the present invention, the engine further comprises a lubricant sump, the pump being fluidly connected to the sump and receiving lubricant from the sump, wherein an area of ​​the cylinder head surrounding the valve spring is fluidly connected to the sump to provide lubricant to the sump; wherein a valve-side end of the valve guide is unsealed to fluidly connect and provide a lubricant flow path from a passage in the valve guide into an area of ​​the cylinder head surrounding the valve spring.

[0006] According to one embodiment of the invention, the channel follows a tortuous path along the inner wall of the conduit.

[0007] According to one embodiment of the present invention, the inner wall of the valve guide defines another channel, which extends from the middle area of ​​the guide to the valve side end, and the guide defines another passage extending outwardly from the other channel to the outer wall at the middle area, and the other passage is fluidly connected to the lubrication channel.

[0008] According to an embodiment of the invention, the channel and the further channel are disjoint.

[0009] In another embodiment, an engine valve guide is provided by an annular cylindrical member having an inner wall and an outer wall intersecting a valve-side end and a port-side end. The inner wall defines a passage extending from the valve-side end to a middle region of the member. The middle region of the member defines a passage extending radially in the region and intersecting the outer wall and the passage.

[0010] According to the present invention, an engine valve guide is provided, comprising: an annular cylindrical member having an inner wall and an outer wall intersecting with a valve-side end and an air port-side end, wherein the inner wall defines a channel extending from the valve-side end to a middle area of ​​the member, wherein the middle area of ​​the member defines a passage extending radially in the middle area and intersecting with the outer wall and the channel.

[0011] According to an embodiment of the invention, said channel follows a spiral path.

[0012] According to one embodiment of the present invention, the inner wall of the component defines a first inner circumferential groove located between the middle area and the air port side end; wherein the inner wall of the component defines a second inner circumferential groove located between the first inner circumferential groove and the air port side end.

[0013] According to one embodiment of the invention, the outer wall of the component defines an outer circumferential groove between the middle area and the gas port-side end.

[0014] In yet another embodiment, a method is provided, the method comprising: providing pressurized lubricant to a lubrication passage defined in a cylinder head, the lubrication passage intersecting a valve guide bore wall of the cylinder head. The lubricant is introduced from the lubrication passage into a passage extending from an outer wall to an inner wall in a middle region of the valve guide. A moving valve stem located within the valve guide is lubricated by flowing the lubricant from the passage into an inlet of the passage intersecting the inner wall and toward an outlet of the passage located at a valve end of the guide, wherein the passage follows a tortuous path along the inner wall of the guide. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of an internal combustion engine in which the disclosed embodiments can be implemented is shown.

[0016] Figure 2It shows that according to the embodiment Figure 1 A cross-sectional view of the cylinder head of an engine.

[0017] Figure 3 Shows Figure 2 Another cross-section of the cylinder head.

[0018] Figure 4 Shows Figure 2 Side view of the valve guide of the cylinder head. DETAILED DESCRIPTION

[0019] As required, specific embodiments of the present disclosure are disclosed herein; however, it should be understood that the disclosed embodiments are merely examples and may be implemented in various alternative forms. The drawings are not necessarily drawn to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, the specific structural details and functional details disclosed herein should not be interpreted as limiting, but merely as a representative basis for teaching those skilled in the art to use the present disclosure in various forms.

[0020] Figure 1 A schematic diagram of an internal combustion engine 20 is shown. The engine 20 has a plurality of cylinders 22, one of which is shown. The cylinder 22 is formed by a cylinder wall 32 and a piston 34, and is also referred to herein as a combustion chamber 22. The piston 34 is connected to a crankshaft 36. The combustion chamber 22 is in fluid communication with an intake manifold 38 and an exhaust manifold 40. One or more intake valves 42 control the flow from the intake manifold 38 into the combustion chamber. One or more exhaust valves 44 control the flow from the combustion chamber to the exhaust manifold 40. The intake valve 42 and the exhaust valve 44 can be operated in various ways known in the field of engine operation control. The operation of the intake valve 42 and the exhaust valve 44 will be described in more detail below.

[0021] Fuel injector 46 delivers fuel from the fuel system directly into combustion chamber 22, so the engine is a direct injection engine. Low-pressure or high-pressure fuel injection systems can be used for engine 20, or in other examples, an intake port injection system can be used. The ignition system includes a spark plug 48, which is controlled to provide energy in the form of a spark to ignite the fuel-air mixture in the combustion chamber. Spark plug 48 can be located in various locations within combustion chamber 22. In other embodiments, other fuel delivery systems and ignition systems or techniques can be used, including indirect injection or compression ignition.

[0022] The engine 20 includes a controller and various sensors configured to provide signals to the controller for controlling air and fuel delivery to the engine, ignition timing, valve timing, power and torque output of the engine, etc. The engine sensors may include, but are not limited to, an oxygen sensor in the exhaust manifold 40 , an engine coolant temperature sensor, an accelerator pedal position sensor, an engine manifold pressure (MAP) sensor, an engine position sensor for crankshaft position, an air mass sensor located in the intake manifold 38 , a throttle position sensor, etc.

[0023] In some embodiments, engine 20 is used as the only prime mover in a vehicle (such as a conventional vehicle or a start-stop vehicle). In other embodiments, the engine can be used in a hybrid vehicle, in which an additional prime mover (such as an electric motor) can be used to provide additional power to propel the vehicle.

[0024] Each cylinder 22 can work under a four-stroke cycle including an intake stroke, a compression stroke, an ignition stroke, and an exhaust stroke. In other embodiments, the engine can operate in a two-stroke cycle. The position of the piston 34 at the top of the cylinder 22 is generally referred to as the top dead center (TDC). The position of the piston 34 at the bottom of the cylinder is generally referred to as the bottom dead center (BDC).

[0025] During the intake stroke, the intake valve 42 opens, the exhaust valve 44 closes, and the piston 34 moves from the top of the cylinder 22 to the bottom of the cylinder 22 to introduce intake gas (e.g., air) from the intake manifold into the combustion chamber. As the piston 34 moves downward during the intake stroke, fuel may be introduced into the cylinder 22.

[0026] During the compression stroke, the intake valve 42 and the exhaust valve 44 are closed. The piston 34 moves from the bottom of the cylinder 22 to the top to compress the air / fuel mixture in the combustion chamber 22.

[0027] The compressed air / fuel mixture is then ignited in combustion chamber 22. In the illustrated engine 20, fuel is injected into combustion chamber 22 and then ignited using spark plug 48. In other examples, the fuel may be ignited using compression ignition or may be introduced into the intake gases prior to the cylinder (e.g., via indirect injection).

[0028] During the expansion stroke, the ignited fuel-air mixture in the combustion chamber 22 expands, causing the piston 34 to move from the top of the cylinder 22 to the bottom of the cylinder 22. The movement of the piston 34 causes a corresponding movement of the crankshaft 36 and provides mechanical torque output from the engine 20.

[0029] During the exhaust stroke, intake valve 42 remains closed and exhaust valve 44 opens. Piston 34 moves from the bottom of the cylinder to the top of cylinder 22 to expel exhaust gas and combustion products from combustion chamber 22 by reducing the volume of combustion chamber 22. Exhaust gas flows from combustion cylinder 22 to exhaust manifold 40 and aftertreatment system (such as catalytic converter).

[0030] The position and timing of the intake valve 42 and the exhaust valve 44 as well as the fuel injection timing and the ignition timing may vary in different engine strokes.

[0031] The engine 20 has an engine cylinder block 50 and a cylinder head 52. A cylinder head gasket 54 is placed between the cylinder block 50 and the cylinder head 52 to seal the cylinder 22.

[0032] The cylinder head 52 defines an intake port 60. The intake port 60 provides a passage for intake air or intake gas to flow from the intake manifold 38 to the corresponding cylinder 22. The intake air may include external or ambient air, may include fuel mixed therein, and may also be mixed with exhaust gas from an exhaust gas recirculation system, etc. The intake port 60 has a valve seat 62. The valve seat 62 serves as an opening into the combustion chamber 22, and the valve seat 62 cooperates with the intake valve 42 to seal the intake port 60 or prevent intake air from flowing into the combustion chamber 22 when the intake valve 42 abuts against the valve seat 62.

[0033] The cylinder head 52 defines an exhaust port 64. The exhaust port 64 provides a passage for exhaust gas to flow from each cylinder 22 to the exhaust manifold 40. The exhaust port has a valve seat 66. The valve seat 66 serves as an opening into the combustion chamber 22, and the valve seat 66 cooperates with the exhaust valve 44 to seal the exhaust port 64 or prevent exhaust gas from flowing into the exhaust port 64 when the exhaust valve 44 abuts the valve seat 66.

[0034] The engine 20 is shown with an intake valve 42 and an exhaust valve 44, wherein the intake valve 42 and the exhaust valve 44 are poppet-type valves in a direct overhead cam configuration. The engine and the intake valve 42 and the exhaust valve 44 can be configured in various ways known in the art, such as a single overhead camshaft, a dual overhead camshaft, a direct camshaft drive, an overhead valve configuration in which the valves are operated by push rods or rockers, etc. Each valve 42, 44 is shown as being mechanically operated by a respective camshaft; however, in other examples, the valves 42, 44 can be hydraulically controlled or electrically controlled.

[0035] The intake valve 42 is described below; however, the exhaust valve 44 has the same or similar components, so in various embodiments, the following description of the intake valve 42 may also apply to the exhaust valve 44. The valve 42 has a valve head 70 that is connected to the end of a valve stem 72. The valve head 70 can have a variety of shapes and is sized to match the valve seat 62 when the valve 42 is in the closed position. The valve head 70 extends radially outward from the valve stem 72.

[0036] The valve stem 72 is actuated by a valve train. In this example, the valve train includes a spring 74 that biases the valve head 70 toward an open position (in which the valve head 70 is away from the valve seat 62) to allow intake gas to enter the cylinder from the intake manifold through the intake port 60. One end of the spring 74 is supported and positioned by a spring seat 75.

[0037] The valve mechanism also includes a tappet 76. The tappet 76 in this example is a barrel-type tappet. The tappet 76 has a surface that contacts a lobe 78 on a camshaft 80. When the camshaft 80 and the lobe 78 rotate, the surface of the lobe 78 interacts with the tappet 76 to press the tappet 76 and move the valve stem 72 and the valve head 70 to a closed position (in which the valve head 70 is seated on the valve seat 62).

[0038] The shape and size of the lobe 78 are suitable for providing the desired valve timing, including the desired lift and duration of the valve 42. In other examples, the valve 42 is controlled to have variable valve timing as known in the art. The valve mechanism may also include various rockers, push rods, etc. as known in the art. At least a portion of the valve mechanism is located in the area 79 of the cylinder head 52.

[0039] The valve 42 also has a valve guide 82. The guide 82 is a cylindrical sleeve that is disposed in the cylinder head to maintain the position of the valve stem and valve head of the valve 42. The valve stem 72 extends through the guide 82 or through the sleeve. A gap is provided between the inner wall of the guide 82 and the valve stem 72 so that the valve stem can slide easily in the guide while preventing gas and lubricant from flowing through the guide. The size of the guide 82 is suitable for allowing diametrical wear throughout the life of the engine while maintaining the gap with the valve stem 72 and the positioning of the valve stem 72. The guide is usually made of steel, steel alloy or other wear-resistant material.

[0040] In engines with conventional intake or exhaust valves, the interface between the valve stem and the inner wall of the guide is usually non-lubricated. For conventional valves, when the valve train is lubricated, a seal is located above the upper end of the valve guide to prevent lubricant from reaching the intake port, exhaust port or combustion chamber.

[0041] For the valves 42, 44 according to the present disclosure, the interface between the valve guide 82 and the valve stem 72 is lubricated, and an additional sealing member is provided to prevent lubricant from flowing through the valve guide and reaching the intake or exhaust ports. Figures 2 to 4 The valves 42 , 44 according to the present disclosure are described in greater detail.

[0042] The engine 20 has a lubrication system (or lubrication circuit) 90 for lubricating the various moving parts of the engine 20, reducing friction and wear on the moving parts, and managing the heat load in the engine. The system 90 can be controlled by a lubrication system controller or an engine controller. The lubrication system 90 can be integrated into the engine 20 and has various casting and / or machining passages in the cylinder block and the cylinder head. These passages are also referred to as passages and may include both high-pressure passages and low-pressure passages. The lubrication system 90 may contain various lubricants as working fluids, which are generally referred to as "oils". The system 90 has one or more pumps 92, an oil cooler 94 or other heat exchangers and filters. The system 90 may also have a reservoir 96 or an oil pan. The lubrication system 90 may provide lubricating fluid for the crankshaft, camshaft and other engine components. The lubricant is shown as being pumped from the reservoir 96 into the passages in the engine to reach the components that need lubrication. The lubricant coming out of the components then flows back to the oil pan through the passages provided in the engine.

[0043] In this example, pump 92 provides pressurized lubricant to valves 42, 44 for lubricating the valve train and bearings associated with the camshaft. The lubricant is then drained from the area in the cylinder head surrounding the valves 42, 44 to an oil sump 96. Pump 92 also provides pressurized lubricant to passages 98 in the cylinder head that are in fluid communication with the valve guides, thereby lubricating the interface between the inner wall of the guides and the moving valve stems.

[0044] Reference Figures 2 to 4 , showing the valves of the cylinder head. The valve described below is the intake valve 42, however, in various embodiments, the valve may alternatively be used as the exhaust valve 44. Figure 1 Elements described that are similar or identical are given the same reference numerals.

[0045] Figure 2 A cross-sectional view of a cylinder head 52 of the engine 20 is shown with valves 42 according to an embodiment. Figure 3 Shown is the valve stem removed Figure 2 Cross-sectional view of . Figure 4 It shows that Figures 2 to 3 Valve guide 82 is shown.

[0046] The cylinder head 52 defines a valve guide bore 100, which, as shown, extends toward the intake port 60 in the case of the intake valve 42, or toward the exhaust port 64 in the case of the exhaust valve 44. The guide bore 100 may be provided in the cylinder head 52 in the form of a cylindrical bore and may be machined or otherwise formed in the cylinder head. For a cylindrical bore 100, the bore wall is a continuous wall. In the example shown, the bore 100 has a constant diameter along the length of the bore.

[0047] The cylinder head 52 defines a lubrication passage 102 that intersects the wall of the valve guide hole 100. The lubrication passage 102 is provided as an internal passage in the cylinder head 52 and receives lubricant from the lubrication circuit 90 of the engine. The lubrication passage 102 is in fluid communication with another oil passage (such as a main oil passage 104 in the cylinder head) and may be directly fluidly connected thereto. The pump 92 in the lubrication circuit 90 provides pressurized lubricant to the main oil passage 104 in the cylinder head, and the pressurized lubricant then flows to the lubrication passage 102. The pressure and flow rate of the pressurized lubricant in the lubrication passage 102 may be lower than the lubrication in the main oil passage 104. In one example, the lubrication passage 102 has a passage with a reduced diameter to limit and restrict the flow of lubricant therethrough. For example, the lubrication passage 102 may have a diameter of about the order of millimeters or less. In one example, the lubrication passage 102 may be provided in the cylinder head 52 and formed by additive manufacturing technology.

[0048] The valve guide 82 is located in the hole 100. The guide 82 can be provided by an annular cylindrical member or a sleeve-shaped member. The guide 82 has an outer wall 110 that contacts and is supported by the cylinder head and an inner wall 112 that surrounds the valve stem 72. The inner wall 112 and the outer wall 110 extend between the valve side end (or valve head end) 114 of the guide and the port side end (or port end) 116 of the guide 82. The valve side end 114 of the guide is the end of the guide that is located near the valve mechanism and surrounded by the valve spring group 74. The port end 116 of the guide is opposite to the valve side end 114 and is located near the intake port 60 (for the intake valve) or the exhaust port 64 (for the exhaust valve). The port end 116 of the guide can be positioned flush or approximately flush with the top of the intake port or the exhaust port. The middle area 118 of the guide 82 is located between the ends 114 and 116 and is spaced apart from them.

[0049] The outer wall 110 may be provided by a generally cylindrical surface received by the cylindrical bore 100 in the cylinder head. The inner wall 112 may be formed by a generally cylindrical surface that receives the valve stem 72. The inner wall 112 may be positioned coaxially with the outer wall 110 about the longitudinal axis of the valve stem 72. The valve stem 72 extends through the valve guide 82 so that the valve head 70 is located in the intake port 60 to engage the valve seat 62.

[0050] The inner wall 112 of the conduit defines a passage 120 extending from a first end 122 located in the middle region 118 of the conduit to a second end 124 located at the valve side end 114 of the conduit. The middle region 118 of the valve conduit is located between the valve side end 114 and the port end 116 and is spaced apart from the valve side end 114 and the port end 116. The passage 120 may be formed as a continuous open passage or groove with a first end 122 located in the middle region of the conduit and a second end 124 located at the valve side end of the conduit. As shown, the second end 124 of the passage may intersect the valve side end surface 114 of the conduit 82.

[0051] The channel 120 is provided by the conduit 82 as an open channel that intersects the inner wall 112 of the valve conduit to provide lubricant to the interface between the inner wall 112 of the conduit and the moving valve stem 72. The channel 120 can follow a continuous curved path along the inner wall 112 of the conduit. In the example shown, the channel 120 follows a spiral path along the inner wall 112 of the conduit. The spiral path may have a constant pitch or a varying pitch. The channel 120 may have a uniform depth along the length of the channel, or may have a varying depth. The cross-sectional shape of the channel 120 may be u-shaped, v-shaped, or other shapes. The channel 120 is shown as circumferentially surrounding the inner wall 112 multiple times, in alternative embodiments, the channel may circumferentially surround the inner wall 112 only once or less. In alternative embodiments, the channel 120 may follow paths of other shapes.

[0052] The valve guide 82 further defines a passage 130 extending outwardly in the intermediate region 118. The passage 130 extends generally radially outwardly in the valve guide 82 from the inner wall 112 to the outer wall 110. The passage 130 fluidly connects the lubrication gallery 102 and the passage 120. The passage 130 and the passage 120 cooperate to form a fluid flow path of the guide 82.

[0053] The passage 130 extends from the first end 122 of the passage to the outer wall 110 of the conduit. The passage 130 is in fluid communication with the lubrication passage 102, so that the passage 130 receives lubricant from the lubrication passage 102 and directs it to the passage 120. The passage 130 has an inlet 132 that intersects the outer wall 110 of the conduit and an outlet 134 that intersects the first end 122 of the passage 120 located in the middle region 118 of the conduit. In a further example, the passage 130 is formed as a closed internal expansion passage of the passage 120, thereby providing a smooth and continuous flow path for the lubricant. The passage 130 can be an extension of a continuous curved path or spiral path of the passage 120.

[0054] In one example, the inlet 132 of the passage overlaps the lubrication passage 102 at the bore wall 100, so that the passage 130 is aligned with the outlet 136 of the lubrication passage. In another example, as shown, the valve guide bore wall 100 of the cylinder head further defines a circumferential groove 138 intersecting the lubrication passage 102. The passage 130 of the guide overlaps the circumferential groove 138 of the valve guide bore wall 100 at the outer wall 110.

[0055] In another example, the lubrication passage 102 does not include the circumferential groove 138 , but instead the outer wall 110 of the valve guide defines a circumferential groove (not shown) at the intermediate region that functions similarly to the groove 138 , the guide side groove intersecting the passage 130 and overlapping the lubrication passage outlet 136 at the bore wall 100 .

[0056] The outer wall 110 of the conduit defines a first circumferential groove 140 located between the middle region 118 and the port-side end 116 of the conduit at the bore wall 100. As shown, the groove 140 is located between the circumferential lubrication groove 138 and the port end 116 of the conduit and the associated intake port 60 in the cylinder head. A first sealing member 142 is positioned within the first groove 140 and in contact with the conduit bore wall 100 to seal the interface between the outer wall 110 of the conduit and the bore wall 100 of the cylinder head and provide a seal between the valve conduit 82 and the air path. The first sealing member 142 may be provided by an O-ring. The first sealing member 142 may be formed of a fluorocarbon-based material or other material having suitable high temperature resistance and chemical resistance.

[0057] The inner wall 112 of the conduit defines a second circumferential groove 150 between the middle region 118 and the port side end 116 of the conduit. As shown, the groove 150 is located between the port end 116 of the conduit and the outlet 134 of the conduit passage 130 and the first end 122 of the passage 120. The second sealing member 152 is positioned in the second groove 150 and contacts the valve stem 72 to seal the interface between the inner wall 112 of the conduit and the valve stem 72 and provide a valve stem seal. In one example, the second sealing member 152 is provided as a main valve stem seal. The second sealing member 152 can be provided by an O-ring. The second sealing member 152 can be formed by a fluorocarbon-based material or other materials with suitable high temperature resistance and chemical resistance.

[0058] The inner wall 112 of the conduit may also define a third circumferential groove 160 between the second groove 150 and the port-side end 116 of the conduit. A third sealing member 162 is positioned in the third groove 160 and contacts the valve stem 72 to seal the interface between the inner wall 112 of the conduit and the valve stem 72 and provide a valve stem seal. In one example, the third sealing member 162 is provided as an auxiliary valve stem seal. The third sealing member 162 may be provided by an O-ring. The third sealing member 162 may be formed of a material having high temperature resistance and chemical resistance, which also provides a low friction interface between the seal and the valve stem, in one example, the third sealing member 162 is formed of a fluorocarbon (such as polytetrafluoroethylene), in another example, the third sealing member 162 is formed as a glass-filled polytetrafluoroethylene O-ring, and in yet another example, the third sealing member 162 is formed as a compressed graphite O-ring sealing member.

[0059] As shown, the valve-side end 114 of the guide tube is not sealed, so that lubricant can leave the passage 120 at the valve-side end 114 of the guide tube and flow into the cylinder head 52, into the space 79 provided for the valve spring group 74. The lubricant then flows from this area 79 into the passage in the cylinder head 52 and the engine 20, which returns the lubricant to the oil pan 96 of the lubrication circuit 90. Conventional valve guides are provided with a sealing member that extends around the valve stem and covers the valve-side end of the guide tube so as to contact or directly surround the valve spring seat. Such conventional sealing members located on the valve-side end of the guide tube are not provided for the valve 42 and cylinder head 52 of the present disclosure, and therefore, as described above, sealing members 142, 152, 162 are provided according to the present disclosure.

[0060] The intermediate region 118 of the conduit can be defined as being spaced apart from the valve-side end 114 and the port end 116 of the conduit, the intermediate region 118 being positioned close to or adjacent to the port end 116 while providing sufficient space for the grooves and sealing members 142, 152, 162. By positioning the intermediate region 118 toward the port end 116, a longer portion of the interface between the inner wall 112 of the conduit and the valve stem 72 is directly lubricated by the passage 120.

[0061] In a further example, the inner wall 112 of the valve guide 82 defines another channel extending from the middle region of the guide to the valve side end of the guide. The guide defines another passage extending outwardly from the other channel to the outer wall at the middle region, wherein the other passage is fluidly connected to the lubrication channel. In this example, the channel and the other channel can be non-intersecting to provide two flow paths or channels for the lubricant along the interface. The other channel and the other passage can be arranged similarly to the channel 120 and the passage 130.

[0062] In general, during engine operation, the present disclosure provides a lubricated interface between the valve stem 72 and the inner wall 112 of the valve guide by providing a continuous flow of pressurized lubricant from the intermediate region 118 of the valve guide 82 toward the valve-side end 114 of the guide, from which the lubricant flows into the valve packaging space 79 in the cylinder head and ultimately back to the oil pan 96. By providing a pressurized flow of lubricant at a controlled pressure and flow rate to the intermediate region 118 of the valve guide 82, lubrication of the interface can be controlled, rather than attempting to lubricate the interface by gravity feed of lubricant from the valve packaging space in the cylinder head.

[0063] The lubrication circuit 90 of the engine uses a pump 92 to provide pressurized lubricant to a lubrication gallery 102 defined in the cylinder head 52, where the lubrication gallery 102 intersects the cylinder head's valve guide bore wall 100. From the lubrication gallery 102, the lubricant is directed into a passage 130 that extends from the outer wall 110 to the inner wall 112 in the intermediate region 118 of the valve guide 82.

[0064] The moving valve stem 72 is located within the valve guide 82, and the interface between the moving valve stem and the surrounding valve guide is lubricated by causing lubricant to flow from the passage 130 into an inlet 122 of a channel 120 that intersects the inner wall 112 of the guide, flow along the channel 120, and flow at the valve-side end 114 of the guide to an outlet 124 of the channel 120. The channel 120 may follow a tortuous path, a spiral path, or other path along the inner wall of the guide.

[0065] The lubricant leaves the passage 120 at the valve-side end 114 of the guide tube, flows into the valve packaging space 79 in the cylinder head, and flows to the lubricant drain passage and lubricant sump 96 in the engine. Therefore, the guide tube 82 is provided with one or more sealing members 142 to seal the interface between the outer wall 110 of the guide tube and the bore wall 100 of the cylinder head to prevent the lubricant leaving the passage 120 from flowing from the valve-side end 114 of the guide tube through the interface and into the intake port 60. Therefore, the interface between the outer wall 110 of the valve guide and the valve guide bore wall 100 is sealed by placing the first sealing member 142 between the middle region 118 of the valve guide and the port end 116 of the valve guide.

[0066] The guide tube 82 is also provided with one or more sealing members 152, 162 to seal the interface between the inner wall 112 of the guide tube and the valve stem 72 to prevent the lubricant in the passage 120 from flowing into the intake port 60 through the interface between the inner wall 112 of the guide tube and the valve stem 72. Therefore, the interface between the inner wall 112 of the valve guide and the valve stem 72 is sealed by placing the second sealing member 152 between the middle region 118 of the valve guide and the gas port end 116 of the valve guide. A third sealing member 162 may also be placed between the second sealing member 152 and the gas port end 116 of the guide tube to provide a secondary seal for the interface.

[0067] Thus, the engine 20 and valve guide 82 according to the present disclosure provide lubrication performance between the moving valve and valve stem 72 of the engine intake valve 42 or exhaust valve 44 and the adjacent valve guide running surface to reduce heat and friction at the interface and improve the performance and efficiency of the entire engine system while preventing lubricant from flowing into the adjacent ports 60, 64.

[0068] Although exemplary embodiments are described above, these embodiments are not meant to describe all possible forms of the present invention. On the contrary, the words used in the specification are descriptive rather than restrictive, and it should be understood that various changes may be made without departing from the spirit and scope of the present disclosure. In addition, the features of various implemented embodiments may be combined to form further embodiments of the present disclosure.

Claims

1. An engine, include: a cylinder head defining a valve guide bore wall and a lubrication passage intersecting the valve guide bore wall, and the valve guide bore wall further defining a circumferential groove intersecting the lubrication passage; as well as A valve guide is accommodated by a valve guide hole wall of a cylinder head, and the valve guide has an inner wall and an outer wall intersecting a valve side end and a port side end, the inner wall defines a channel extending from a middle area of ​​the valve guide to the valve side end, and the valve guide defines a passage extending outwardly from the passage at the middle area to the outer wall, the passage being fluidly connected to the lubrication passage.

2. The engine according to claim 1, in, The passage of the valve guide overlaps the circumferential groove of the valve guide bore wall at the outer wall.

3. The engine of claim 1 further comprising a pump fluidly connected to the lubrication passage and providing pressurized lubricant to the lubrication passage.

4. The engine of claim 3, further comprising an oil sump for containing lubricant, the pump being fluidly connected to the oil sump and receiving the lubricant from the oil sump; in, The valve-side end of the valve guide is not sealed, so that lubricant is arranged to flow from the channel in the valve guide into the region of the cylinder head surrounding the valve spring and then to the oil sump.

5. The engine according to claim 1, in, The passage is an open passage that intersects the inner wall of the valve guide; The passage of the valve guide extends radially outward in a middle region of the valve guide, and the passage has an inlet intersecting with an outer wall of the valve guide and an outlet intersecting with the channel at the middle region.

6. The engine according to claim 1, in, The passage follows a helical path along the inner wall of the valve guide.

7. The engine according to claim 1, in, The inner wall of the valve guide defines another passage extending from a middle region of the valve guide to a valve-side end thereof, the valve guide defines another passage extending outwardly from the another passage to the outer wall at the middle region, the another passage being fluidly connected to the lubrication passage; Wherein, the channel and the another channel are disjoint.

8. The engine according to claim 1, in, One of the valve guide bore wall and the valve guide outer wall defines a first circumferential groove between the middle region and the port-side end; The engine further comprises a first sealing component located in the first circumferential groove and in contact with the valve guide hole wall and the outer wall of the valve guide.

9. The engine as claimed in claim 8, in, The inner wall of the valve guide defines a second circumferential groove between the middle region and the port-side end; The engine further comprises a second sealing member located in the second circumferential groove and in contact with the valve stem.

10. The engine according to claim 9, in, Each of the first sealing member and the second sealing member includes an O-ring.

11. The engine according to claim 9, in, The inner wall of the valve guide defines a third circumferential groove between the second circumferential groove and the port-side end; The engine further comprises a third sealing member located in the third circumferential groove and in contact with the valve stem.

12. An engine, include: a cylinder head defining a valve guide bore wall and a lubrication passage intersecting the valve guide bore wall; a valve guide received by a valve guide bore wall of a cylinder head, the valve guide having an inner wall and an outer wall intersecting a valve-side end and a port-side end, the inner wall defining a passage extending from a middle region of the valve guide to the valve-side end, the valve guide defining a passage extending outwardly from the passage at the middle region to the outer wall, the passage being fluidly connected to the lubrication passage, The outer wall of the valve guide further defines a circumferential groove located at a middle area, the circumferential groove intersects with the passage, and the circumferential groove of the valve guide overlaps with the lubrication passage.

13. A method for lubricating a mobile valve stem of an engine, include: providing pressurized lubricant to a lubrication passage defined in the cylinder head, the lubrication passage intersecting a valve guide bore wall of the cylinder head; introducing lubricant from the lubrication channel into a passage extending from the outer wall to the inner wall in a middle region of the valve guide; lubricating a moving valve stem within a valve guide by causing lubricant to flow from the passageway into an inlet of a channel intersecting the inner wall and to an outlet of the channel at a valve end of the valve guide, the channel following a tortuous path along the inner wall of the valve guide; as well as The interface between the outer wall of the valve guide and the valve guide bore wall is sealed by placing a first sealing member between the middle region of the valve guide and the port end of the valve guide, the first sealing member contacts the valve guide bore wall of the cylinder head and the outer wall of the valve guide.

14. The method according to claim 13, in, The valve guide bore wall further defines a circumferential groove that intersects the lubrication passage.

15. The method of claim 13, include: The interface between the inner wall of the valve guide and the valve stem is sealed by placing a second sealing member between the intermediate region of the valve guide and the port end of the valve guide.

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