Protective cover for a crankcase ventilation connection and method for manufacturing

Abstract

Intake system comprising: a shell of an intake manifold (60); an inner PCV channel (82) extending inwards from the shell; and an outer PCV channel (80) extending outwards from the shell, the inner PCV channel (82) having a protective cover (84, 85, 210, 230, 240, 250); and the protective cover (84, 85, 210, 230, 240, 250) having at least one first opening (214, 234, 244, 254) having a center line (212, 232, 242, 262) that is one of the following: perpendicular to a center line of the inner PCV channel (202) and forming an obtuse angle (270) with it.

Description

Field of InterestThe present invention relates to crankcase ventilation systems in internal combustion engines, and more particularly to the port in the intake system through which blowby gases flow.General State of the ArtA positive crankcase ventilation (PCV) system for an internal combustion engine is shown in FIG. 1. An internal combustion engine 10 includes a crankcase 12 with oil 14 in an oil pan. Oil mist is formed by the crankshaft 16 having connecting rods coupled thereto. The oil mist forms in the crankcase due to oil flying away from the rotating components. A small portion of the combustion gases in the combustion chamber 50 pass a piston 20 into the crankcase 12. Instead of venting these gases to the atmosphere, they are introduced into the combustion chamber to be burned. The crankcase 12 is in fluid communication with a volume above the valve train of a cylinder head 24. the engine 10 is a two-bank V-engine. A PCV valve 26 is provided in one of the banks. A PCV passage 28 is connected between the PCV valve 26 and an intake manifold 44. The PCV passage 28 includes a port 30 where it is connected to the intake manifold 44. Fresh air is introduced into the engine 10 via an intake passage 40 in which a throttle valve 42 is disposed. Fresh gases are provided to the intake manifold 44 and mix with the blowby gases from the PCV passage before entering the combustion chamber 50.Blowby gases are predominantly exhaust gases containing about 12% water vapor. During cold weather operation, water vapor may freeze in the PCV system, disrupting proper operation. It is known to use heating elements to prevent freezing of the PCV valve, as described in U.S. Pat. No. 6,546,921 B2. Additionally, the water may freeze in the port 30, i.e., the port through which the blowby gases enter the intake manifold to mix with fresh air. The port 30 in FIG. 1 is positioned on the wall of the intake manifold 44. To promote mixing, the passage 28 often extends into the manifold 44 such that the port 30 is closer to the center of the manifold 44. In such a configuration, the flow of gases into the port 30 is. When much fresh cold air flows through the port, the water vapor freezes in the port, hindering the flow.US 2004 / 0 144 373 A1 discloses an intake system comprising: a shell of an intake manifold; an inner PCV passage extending inward from the shell; and an outer PCV passage extending outward from the shell.US 2016 / 0 201 620 A1 discloses an intake manifold comprising: (a) a first shell of an intake manifold having an integral PCV passage extending therethrough; a protective cover having a first opening; wherein a centerline of the first opening is offset from a centerline of the integral PCV passage, and (b) a first shell having a second opening; an inner PCV passage connected to the second opening; a protective cover connected to a downstream end of the inner PCV passage; and an outer PCV passage connected to the first shell near the inner PCV passage, wherein the first shell has a first skirt near the second opening; and the inner PCV passage has a second skirt.SummaryIn many PCV duct installations into an intake manifold, the port of the duct is not exposed to incoming fresh intake gases that may freeze in the duct during cold and adversely affect PCV operation. However, some engine packs impose restrictions that force the PCV port into the incoming gases. To overcome the possibility of freezing, a cover is placed on one end of the channel. The cover closes the top of the channel and provides openings in the side surface of the cover.Brief Description of the DrawingsFIG. 1 is an illustration of a PCV system for an internal combustion engine; FIGS. 2 and 13 are illustrations of an intake manifold having a PCV port with a cover over the PCV port, according to an embodiment of the disclosure; FIG. 3 shows an outer wall of the intake manifold of FIG. 2 ; FIG. 4 is a view of an embodiment of an outer PCV channel; FIG. 5 is a view of a lower shell of the intake manifold of FIG. 2 ; FIGS. 6 and 7 are a close-up view and a cross-sectional view of a portion of the intake manifold of FIG. 2 ; FIGS. 8-11 are alternative embodiments for an internal PCV channel; and FIGS. 12 and 14 are flowcharts showing a process by which intake manifolds are manufactured according to embodiments of the disclosure.Detailed DescriptionThose of ordinary skill in the art will understand that various features of the embodiments illustrated and described with respect to any of the figures may be combined with features illustrated in one or more other figures to produce alternative embodiments that are not expressly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of the present disclosure may be desirable for particular applications or implementations. Those of ordinary skill in the art will recognize similar applications or embodiments whether or not expressly described or illustrated.In FIG. 2, an intake manifold 60 is comprised of an upper shell 62 and a lower shell 64 In the view of FIG. 2, the upper shell 62 is mainly visible. A cut-out of the upper shell 62 is shown near a PCV channel to provide a view of that element. The lower shell 64 is partially visible through the cut-out. Fresh gases enter manifold 60 through inlet 70 in the direction shown by arrow 90 and then flex as shown by arrow 92. Air is then provided to four runners 74 to supply four cylinders, as shown by arrows 94. Blowby gases flow into an outer PCV passage 80 via a PCV valve and pipe (not shown). outer PCV passage 80 includes a stub 86 for connection to the pipe. An inner PCV passage 82 extends into the manifold 60 to introduce blowby gases into the intake flow. In the embodiment shown in FIG. 2, the inner PCV channel includes a cover 84. In this example, the cover 84 is an elbow at the end of the channel 82. the cover 84 has an opening 86 whose centerline is perpendicular to a centerline of the channel 82. It has been found that freezing or leakage of water vapor is sufficiently reduced as long as the flow of fresh intake gases is not directed directly to the opening of the PCV port.In many situations, the PCV passage may be disposed within the intake manifold such that the flow of fresh gases does not directly affect the port of the PCV passage. However, in the example shown in FIG. 2, due to the packaging and configuration of the intake manifold, the only space available for an internal PCV passage is directly in the intake flow.FIG. 3 shows a portion of the lower shell 64 of the intake manifold. The wall of the lower shell 64 has an opening 102 to which the outer PCV channel (not shown) is fluidly connected. In FIG. 4, the outer PCV channel 80 includes a flange 106. In some embodiments, the main intake manifold housing of FIG. 3 is made of plastic that includes soot. The channel 80 and flange 106 are made of the same or similar plastic as the lower shell 64, but without carbon black. Referring again to FIG. 3, a flange 108 on the wall of the lower shell 64 includes a weld bead 104 surrounding the opening 102. A laser is used to weld the flange 106 of the outer PCV duct to a housing 100 via a weld bead 104. The laser beam is largely transmitted through the flange 106 which does not include soot and is directed at the weld bead 104 which absorbs and melts the laser energy. As the weld bead 104 cools, a seal is formed between the flange 106 of the channel 80 and the housing 100.A lower shell 64 has an inlet 70 and leads to the inside of a manifold 75 leading to the intake ports of an engine (not shown). The outer PCV channel 80 is connected to the lower shell 64, and the inner PCV channel 82 is fixed in the lower shell 64. Details of the connection of channels 80 and 82 to the lower shell are shown in greater detail in an enlarged cross-sectional view in Fig. 6. The outer PCV channel 80 includes a flange 106 that abuts the flange 108 of the lower shell 64. The inner PCV channel 82 includes a cover 85, which is an elbow or alternatively a tee. The inner PCV channel 82 is mounted by inserting a cover end 85 into the opening in the lower shell 64. Due to a skirt 110 extending outward from the inner PCV channel 82 and engaging a skirt 112 of the lower shell 64, the inner PCV channel 82 does not drop through the opening. In some embodiments, the inner PCV channel 82 is not attached to the lower shell 64; it is simply press fit against the skirt 112. A seal is provided by a laser weld or other weld between the flange 106 of the outer PCV duct 80 and the flange 108 of the lower shell 64. In FIG. 7, a cross-sectional view of portions of the PCV channels and the lower shell 74 is shown. The flange 108 additionally includes a key slot 124 that is engaged by a key 120 of the inner PCV channel 82 (only the key 120 of the inner PCV channel 82 is visible in FIG. 7 ). By engaging key 120 with key slot 124, inner channel 82 is divided to ensure a desired position of inner PCV channel 82 such that the cover is positioned in a desired and repeatable configuration.In the embodiment shown in FIGS. 2-7, the PCV channels 80 and 82 are formed separately from the lower shell 64 and are then assembled. Alternatively, the inner and outer PCV passages are integrally molded with the lower shell of the intake manifold. A cover is separately formed before being attached to the tip of the inner portion of the PCV channel. The elbow embodiment of the channel 82 is a possible configuration for such an embodiment. Additional alternatives are shown in Figures 8-11. In FIG. 8, a portion of a straight channel 200, i.e., a portion of the inner PCV channel, has a centerline 202. A cover 210 has four openings 214, one directly midway in the view of Figure 8, one directly behind the one centered in the view, and upper and lower. A centerline 212 of the upper and lower openings is perpendicular to the centerline 202 of the channel 200. The cover 210 includes a cap 216 so that fresh suction flow shown by arrow 220 in Figure 8 is prevented from entering the channel 200 directly, but instead enters via the apertures 212. In one embodiment in Figure 9, a cover 230 has eight openings around the periphery of the cover. The top and bottom openings 234 have a centerline 232 that is perpendicular to the centerline 202 of the channel 200. All of the apertures 234 have centerlines that are substantially perpendicular to the centerline 202. For the sake of simplicity, these are not illustrated in FIG. 9. The cover 230 includes a conical cover 236 which extends to a point 238. It may provide some advantage that the conical cover 236 guides an intake air flow (arrow 220) around the obstruction that the cover 230 and the duct 200 present. In FIG. 10, the cover 240 is a T portion connected to the channel 200. A central axis 242 through apertures 244 is perpendicular to the central axis 202. The arms of the tee 240 may be shortened to present less obstruction within the intake manifold.The embodiments of Figures 8-10 show centerlines of the openings perpendicular to the centerline of the channel 200. For even greater protection from freezing, the holes may be pulled up under the cover, as shown in Figure 11. A cover 250 has a plurality of apertures 254 protected by the widest portion of the cover 250. A centerline 262 of one of the openings 254 forms an obtuse angle 270 with a centerline 202 of the channel 200. A centerline of the channel 200 shown by the current direction of the arrow 260 forms an angle greater than 90 degrees with respect to a centerline of the opening 254.Referring now to FIG. 12, a method of manufacturing a portion of an intake manifold is shown. In blocks 300, 302, 304, and 306, the lower shell, the inner PCV channel, the outer PCV channel, and the upper shell are each injection molded or formed by any suitable method. The lower shell has an opening for a PCV channel, a weld bead on the top surface of the housing surrounding the opening, a skirt for engaging the inner PCV channel. At block 308, the inner PCV channel is rotated so that the key of the channel engages the key slot of the lower shell. In block 312, the outer PCV passage is laser welded to the exterior of the lower shell at a flange of the lower shell of the intake manifold. The outer PCV channel is made of the same or similar plastic as the housing and the inner PCV channel, except that the inner PCV channel and the housing include carbon black and the outer PCV channel does not. A laser is used to heat the weld bead after it passes the flange on the outer PCV channel. In block 314, the lower shell is friction welded to the upper shell.In an alternative embodiment in FIG. 13, a lower shell 400 includes an outer PCV channel 410 and an inner PCV channel 412 formed as a unitary part with the lower shell 400. A pin may be pulled to form the inside of channels 410 and 420 and an opening through the wall of lower shell 400. In Figure 13, a cover 414 is shown separated from a channel 422. The cover 414 is to be connected to a tip 422 of the channel 412 with the channel 412 that is connected to a surface 424 of the cover 414. The cover 414 and the channel 412 may be joined by friction welding, spin welding, sonic welding, ultrasonic welding, and an adhesive. The cover 414 is a T-piece. Other cover configurations, such as a bracket or the examples shown in FIGS. 8, 9, and 11, or any other suitable alternatives, may replace the T-piece.In FIG. 14, the lower shell of the intake manifold, the cover for the tip of the inner PCV passage, and the upper shell of the intake manifold are injection molded in blocks 320, 322, and 326, respectively. The lower shell has a unitary PCV channel extending therethrough and including the inner PCV channel and the outer PCV channel. In block 328, the cover at the inner end of the PCV duct is joined by any suitable technique, such as sonic welding, spin welding, friction welding, and applying an adhesive. In block 330, the upper shell of the manifold is welded or attached to the lower shell of the manifold and suitably sealed.While the best mode has been described in detail with respect to certain embodiments, those skilled in the art will recognize various alternative designs and embodiments that are within the scope of the following claims. While various embodiments may be described as providing advantages or being preferred over other embodiments with respect to one or more desired characteristics, those of ordinary skill in the art will appreciate that one or more characteristics may be compromised to achieve the desired attributes of the system, which depend on the particular application and implementation. These attributes include, but are not limited to: cost, strength, durability, lifetime costs, marketability, appearance, packaging, size, serviceability, weight, machability, ease of assembly, etc. The embodiments described herein that are characterized as less desirable than other embodiments or prior art implementations with respect to one or more properties are not outside the scope of the disclosure and may be desirable in particular applications.

Claims

An intake system comprising: a shell of an intake manifold (60); an inner PCV passage (82) extending inward from the shell; and an outer PCV passage (80) extending outward from the shell, the inner PCV passage (82) having a protective cover (84, 85, 210, 230, 240, 250); and the protective cover (84, 85, 210, 230, 240, 250) having at least one first opening (214, 234, 244, 254) having a centerline (212, 232, 242, 262) that is one of: perpendicular to and forming an obtuse angle (270) with a centerline of the inner PCV passage (202).The intake system of claim 1, wherein the outer PCV passage (80) is integrally formed with the shell of the intake manifold (60).The intake system according to claim 1, wherein the inner PCV passage (82) is formed integrally with the shell of the intake manifold (60); the protective cover (84, 85, 210, 230, 240, 250) is formed separately from the inner PCV passage (82); and the protective cover (84, 85, 210, 230, 240, 250) is attached to the inner PCV passage (82) by an adhesive or welding.The intake system according to claim 1, wherein the protective cover (84, 85, 210, 230, 240, 250) covers the cross section of the inner PCV duct (82) as viewed along a central axis of the inner PCV duct (82).The intake system of claim 1, further comprising: a PCV valve (26) fluidly connected to the outer PCV passage (80), the PCV valve (26) upstream of the outer PCV passage (80).The intake system of claim 1, wherein the protective cover (84, 85, 210, 230, 240, 250) comprises one of an elbow and a tee.The intake system of claim 1, wherein the shell has a second opening in the wall to which the inner PCV passage (82) and the outer PCV passage (80) are fluidly connected; the inner PCV passage (82) has a key (120) that engages a key slot (124) defined in the shell proximate the second opening (102).The intake system of claim 1, wherein the shell has a second opening (102) in the wall to which the inner PCV channel (82) and the outer PCV channel (80) are fluidly connected, the system further comprising: a first skirt (112) on the shell that overlies the second opening (102); a second skirt (110) on the inner PCV channel (82) that engages the first skirt (112).The intake system of claim 1, wherein the shell has a second opening (102) in the wall; and the shell is a first shell (64), the intake system further comprising: a second shell (62) of the intake manifold (60) attached to the first shell (64) after the inner PCV passage (82) is inserted into the second opening (102).The intake system of claim 1, wherein the shell has a second opening (102) in the wall to which the inner PCV conduit (82) and the outer PCV conduit (80) are fluidly connected; the shell has a first flange (108) on an outer surface of the shell; the second opening (102) is defined by the first flange (108); the first flange (108) has a weld bead (104) surrounding the second opening (102); the outer PCV conduit (80) has a second flange (106); and the second flange (106) is welded to the first flange (108) via the weld bead (104).The intake system of claim 1, wherein the inner PCV duct (82) is integrally molded with the shell by injection molding; the outer PCV duct (80) is integrally molded with the shell by injection molding; the protective cover (84, 85, 210, 230, 240, 250) is formed separately from the inner PCV duct (82); and the protective cover (84, 85, 210, 230, 240, 250) is attached to the inner PCV duct (82).An intake manifold (60) comprising: a first shell (64) of an intake manifold (60) having an integral PCV passage extending therethrough; a protective cover (84, 85, 210, 230, 240, 250) having a plurality of first openings (214, 234, 244, 254); wherein the protective cover (84, 85, 210, 230, 240, 250) is attached to an inner tip (422) of the integral PCV passage, and wherein a centerline of the first openings (214, 234, 244, 254) is offset from a centerline of the integral PCV passage.The intake manifold (60) of claim 12, further comprising: a second shell (62) of an intake manifold (60); wherein the second shell (62) is attached to the first shell (64).An intake manifold (60) comprising: a first shell (64) having a second opening (102); an inner PCV passage (82) connected to the second opening (102); a protective cover (84, 85, 210, 230, 240, 250) connected to a downstream end of the inner PVC passage (82); and an outer PCV passage (80) connected to the first shell (64) proximate the inner PCV passage (82), the first shell (64) having a first skirt (112) proximate the second opening (102); and the inner PCV channel (82) includes a second skirting (110), the second skirting (110) engaging the first skirting (112) prior to welding the outer PCV channel (80) to the first shell (64).The intake manifold (60) of claim 14, wherein the protective cover (84, 85, 210, 230, 240, 250) is closed in a direction along the inner PVC duct (82) and includes at least one first opening (214, 234, 244, 254); and the at least one first opening (214, 234, 244, 254) includes a centerline that is offset from a centerline of the inner PCV duct (82).The intake manifold (60) of claim 14, further comprising: a second shell (62) of an intake manifold (60); wherein the second shell (62) of the intake manifold (60) is attached to the first shell (64).The intake manifold (60) of claim 14, further comprising: a key (120) formed on a surface of the inner PCV passage (82); and a key slot (124) defined on a surface of the first shell (64) proximate the second opening (102), the key (120) engaging the key slot (124).The intake manifold (60) of claim 14, wherein the first shell (64) has a first flange (108) with a weld bead (104) surrounding the second opening (102); the outer PCV passage (80) has a second flange (106); the first shell (64) is made of a material containing soot; and the outer PCV passage (80) is made of a material transmitting laser light, the second flange (106) being laser welded to the first flange (108).The intake manifold (60) of claim 14, wherein the outer PCV passage (80) has a stub (86) on the outer surface.

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