Plenum intake manifold for an engine

Abstract

An air intake assembly for a small engine includes a plenum housing defining an internal volume; a first intake runner coupled to the plenum housing and extending between a first cylinder end and a first plenum end, and a second intake runner coupled to the plenum housing and extending between a second cylinder end and a second plenum end. A portion of the first intake runner extends into the plenum housing by a first extension distance so that the first plenum end is arranged within the internal volume. A portion of the second intake runner extends into the plenum housing by a second extension distance so that the second plenum end is arranged within the internal volume.

Description

Atty. Dkt. No. 016831-1982PLENUM INTAKE MANIFOLD FORAN ENGINECROSS-REFERENCE TO RELATED PATENT APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 714,959, filed November 1, 2024, which is incorporated by reference herein in its entirety.BACKGROUND

[0002] Small air-cooled internal combustion engines are typically installed on chore products or outdoor power equipment to power various implements (e.g., pumps, blades, augers, wheels, etc.).SUMMARY

[0003] In some aspects, the present disclosure relates to an air intake assembly for a small engine, the air intake assembly including: a plenum housing defining an internal volume; a first intake runner coupled to the plenum housing and extending between a first cylinder end and a first plenum end, wherein a portion of the first intake runner extends into the plenum housing by a first extension distance so that the first plenum end is arranged within the internal volume; and a second intake runner coupled to the plenum housing and extending between a second cylinder end and a second plenum end, wherein a portion of the second intake runner extends into the plenum housing by a second extension distance so that the second plenum end is arranged within the internal volume.

[0004] In some aspects, the present disclosure relates to an engine assembly including: an engine block; a crankshaft at least partially arranged within the engine block; a blower assembly coupled to the engine block and configured to provide cooling air to the engine block; and an air intake assembly including: a plenum housing defining an internal volume; a first intake runner coupled to the plenum housing and extending between a first cylinder end and a first plenum end, wherein a portion of the first intake runner extends into the plenum housing by a first extension distance so that the first plenum end is arranged within the internal volume; and a second intake runner coupled to the plenum housing and extending between a second cylinder end and a second plenum end,-1-4897-8690-2133Atty. Dkt. No. 016831-1982 wherein a portion of the second intake runner extends into the plenum housing by a second extension distance so that the second plenum end is arranged within the internal volume.

[0005] In some aspects, the present disclosure relates to a method of assembling an engine assembly, including: coupling a first end of first intake runner to a first cylinder head; coupling a second end of first intake runner to a second cylinder head; coupling the first intake runner to the plenum housing with a second end of the first intake runner extending a first distance into the plenum housing; and coupling the second intake runner to the plenum housing with a second end of the second intake runner extending a second distance into the plenum housing.

[0006] This summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the devices or processes described herein will become apparent in the detailed description set forth herein, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements.BRIEF DESCRIPTION OF THE FIGURES

[0007] The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements, in which:

[0008] FIG. 1 is a perspective view of an engine assembly, according to an exemplary embodiment;

[0009] FIG. 2 is a front view of the engine assembly of FIG. 1;

[0010] FIG. 3 is a side view of the engine assembly of FIG. 1;

[0011] FIG. 4 is a front perspective view of a plenum intake assembly of the engine assembly of FIG. 1;

[0012] FIG. 5 is a front perspective view of the plenum intake system of FIG. 4 with a plenum housing shown as transparent;

[0013] FIG. 6 is a rear view of the plenum intake system of FIG. 4, with the plenum housing shown as transparent;-2-4897-8690-2133Atty. Dkt. No. 016831-1982

[0014] FIG. 7 is a top view of the plenum intake system of FIG. 4, with the plenum housing shown as transparent;

[0015] FIG. 8 is a cross-sectional view of the plenum intake system of FIG. 7 taken along line8-8;

[0016] FIG. 9 is a cross-sectional view of the plenum intake system of FIG. 7 taken along line9-9;

[0017] FIG. 10 is a front perspective view of the plenum intake system of FIG. 4 coupled to an air filter;

[0018] FIG. 11 is a rear perspective view of the plenum intake system of FIG. 4 coupled to an air filter;

[0019] FIG. 12 is a perspective view of an engine assembly, according to an exemplary embodiment;

[0020] FIG. 13 is a front view of the engine assembly of FIG. 12;

[0021] FIG. 14 is a side view of the engine assembly of FIG. 12;

[0022] FIG. 15 is a front perspective view of a plenum intake assembly of the engine assembly of FIG. 12;

[0023] FIG. 16 is a front perspective view of the plenum intake system of FIG. 15 with a plenum housing shown as transparent;

[0024] FIG. 17 is a top view of the plenum intake system of FIG. 15, with the plenum housing shown as transparent;

[0025] FIG. 18 is a front view of the plenum intake system of FIG. 15, with the plenum housing shown as transparent;

[0026] FIG. 19 is a cross-sectional view of the plenum intake system of FIG. 17 taken along line 19-19;

[0027] FIG. 20 is a front perspective view of the plenum intake system of FIG. 15 coupled to an air filter; and-3-4897-8690-2133Atty. Dkt. No. 016831-1982

[0028] FIG. 21 is a rear perspective view of the plenum intake system of FIG. 4 coupled to an air filter.DETAILED DESCRIPTION

[0029] Before turning to the figures, which illustrate certain exemplary embodiments in detail, it should be understood that the present disclosure is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology used herein is for the purpose of description only and should not be regarded as limiting.

[0030] The use herein of the term “axial” and variations thereof refers to a direction that extends generally along an axis of symmetry, a central axis, or an elongate direction of a particular component or system. For example, axially extending features of a component may be features that extend generally along a direction that is parallel to an axis of symmetry or an elongate direction of that component. Similarly, the use herein of the term “radial” and variations thereof refers to directions that are generally perpendicular to a corresponding axial direction. For example, a radially extending structure of a component may generally extend at least partly along a direction that is perpendicular to a longitudinal or central axis of that component. The use herein of the term “circumferential” and variations thereof refers to a direction that extends generally around a circumference or periphery of an object, around an axis of symmetry, around a central axis, or around an elongate direction of a particular component or system.

[0031] The use of the terms “downstream” and “upstream” herein indicate direction relative to the flow of a fluid. The term “downstream” corresponds to the direction of fluid flow, while the term “upstream” refers to the direction opposite or against the direction of fluid flow.

[0032] Referring to the figures generally, the engines and engine assemblies described herein may be used in chore products, including outdoor power equipment, standby generators, portable jobsite equipment, or other appropriate uses. Outdoor power equipment may include lawn mowers, riding tractors, snow throwers, pressure washers, portable generators, tillers, log splitters, zero-turn radius mowers, walk-behind mowers, wide-area walk-behind mowers, riding mowers, standing mowers, industrial vehicles such as forklifts, utility vehicles, etc. Outdoor power equipment may, for example, use an internal combustion engine to drive an implement, such as a-4-4897-8690-2133Atty. Dkt. No. 016831-1982 rotary blade of a lawn mower, a pump of a pressure washer, an auger of a snow thrower, the alternator of a generator, and / or a drivetrain of the outdoor power equipment. Portable jobsite equipment includes portable light towers, mobile industrial heaters, and portable light stands.

[0033] A “chore product” as used herein refers to any type of equipment, machine, or vehicle that may be used to perform a chore (e.g., an outdoor chore, an indoor chore, lawn care, etc.). For example, a chore product may include a motor, a pump, an actuator, a compressor, and / or another device that is electrically powered to operate some function of the chore product to facilitate performing a chore. In some embodiments, a chore is a task performed, either by a user or autonomously, at or near a household, a farm, an agricultural facility, a building, a sidewalk, a park, a parking lot, a forest, a field, and / or a lawn. In some embodiments, a chore product transports an operator and performs a chore. In some embodiments, a chore product autonomously operates to perform a chore without an operator being present on the chore product or physically / manually manipulating the chore product.

[0034] Small engines may include cooling systems. Common cooling system configurations for small engines include air cooling. An air-cooled system generally includes a blower system having a blower housing and a fan within the blower housing. Each of the cylinders of the engine includes fins, which increase the surface area of the cylinders to maximize the heat transfer from the cylinder to the surrounding air. A fan directs airflow over the cylinders to dissipate heat from the engine.

[0035] Small engines are typically designed to be compact to meet the specific mounting and performance requirements of their applications. One aspect of engine design is the intake system, which directly influences the engine’s power output and overall performance. The air intake systems for conventional small engines are generally constrained by packaging limitations within the equipment, and / or by the use of unitary components (e g., a single casting or manifold that connects between two or more cylinders) that do not allow flexibility in the geometry and overall shape of the intake. The need to accommodate various components, including the cylinders themselves and auxiliary systems such as air-cooling blowers, often results in compromises in the design of intake runners or manifold pipes. In many cases, these constraints in conventional intake manifolds have led to the intake runners for each cylinder not being geometrically tuned (e.g., a-5-4897-8690-2133Atty. Dkt. No. 016831-1982 length of each intake runner) to match performance from cylinder to cylinder (e.g., intake pressure balancing), which results in reduced engine performance.

[0036] The systems and methods of the present disclosure provide a plenum intake manifold or assembly that includes a plenum housing. The plenum housing defines a volume that provides space to accommodate intake runners of varying size, shape, and length, so that the intake runners may be geometrically tuned to balance the intake pressure from cylinder to cylinder. For example, the plenum housing may receive a first intake runner that extends into the volume at a first side of the plenum housing and a second intake runner that extends into the volume at a second side of the plenum housing. The volume defined by the plenum housing provides sufficient space so that the first intake runner and the second intake runner may extend into the volume either a similar distance or different distances, depending on the overall length of the intake runner required to pressure balance the intake pressures for a particular engine application and / or operating condition. Additionally, the first intake runner, the second intake runner, and the plenum housing may define a multi-piece assembly, with the first intake runner being coupled to the first side of the plenum housing and the second intake runner being coupled to the second side of the plenum housing. Because of the multi-piece design and the space provided by the volume within the plenum housing, intake runners of varying lengths may be installed on the plenum housing without changing the mounting footprint of the plenum intake manifold on the engine. That is, the intake runners may extend different lengths into the volume of the plenum housing, depending on the overall length of the intake runner, but connection between the plenum housing and the engine (e g., intake ports) for each of the intake runners remains the same, regardless of the overall length of the intake runner.

[0037] Referring to FIGS. 1-3, an engine assembly 10 is shown according to an exemplary embodiment. The engine assembly 10 may include an engine 12, which may be an air-cooled small engine 12. The engine 12 includes pistons moveable within cylinders 13 formed in an engine block 17 along a cylinder axis. The reciprocating motion of the pistons rotates a crankshaft 14 about a crankshaft axis 16 (see FIG. 3). A cylinder head 15 is coupled to the engine block 17 above each of the cylinders 13 to enclose the pistons within the cylinders 13. In some embodiments, the cylinder heads 15 include valving (e.g., intake and exhaust valves) that open and close at predetermined times during the combustion cycle (e.g., as governed by a cam shaft).-6-4897-8690-2133Atty. Dkt. No. 016831-1982

[0038] In the illustrated embodiment, the engine 12 is a vertical-shaft configuration with the crankshaft 14 extending along a vertical direction (e.g., up and down from the perspective of FIG. 3). In some embodiments, the engine 12 may be in a horizontal-shaft configuration. In some embodiments, a flywheel is coupled to the crankshaft 14 and is positioned near the top of the engine 12, above the engine block 17. The engine 12 further includes a plenum intake assembly or manifold 100, which will be discussed in further detail below. The engine 12 may include two cylinders 13 arranged in a V-twin configuration. However, a broad range of engines may benefit from the teachings disclosed herein. For example, the engine 12 may include a single cylinder 13 or three or more cylinders 13 in any of a number of different configurations (e.g., inline, horizontally opposed, etc.), or may have a two-stroke cycle. The engine 12 may be configured to power a broad range of equipment or chore products, including walk-behind lawn mowers, zeroturn radius mowers, lawn tractors, pressure washers, electric generators, snow throwers, and other outdoor power equipment.

[0039] The engine 12 further includes a blower assembly 19 configured to direct air to the engine block 17 to cool the engine 12 by removing waste heat from the engine block 17. The blower assembly 19 includes a blower housing 20 (e.g., engine cover, engine shroud, etc.) coupled to the top of the engine 12. The blower housing 20 includes a central portion 22 including an opening 24 through which the air passes to the engine block 17. According to an exemplary embodiment, the blower housing 20 is configured for use with the engine 12 having a V-twin arrangement and may be shaped to generally conform with the shape of the engine block 17. The central portion 22 is aligned with the crankshaft 14.

[0040] The blower assembly 19 may be an active system with components that draw air in through the blower housing 20 to cool the engine 12 (e.g., provide cooling to the cylinders 13 and / or the engine block 17). The blower assembly 19 may include a blower fan coupled to the flywheel. The fan rotates about the crankshaft axis 16. The fan 26 may include a plurality of fan blades configured to direct cooling airflow through an airspace defined between the engine block 17 and the blower housing 20.

[0041] The engine assembly 10 may include a muffler 32 that is directly coupled to the exhaust outlets or ports of the engine 12. Each exhaust outlet may output exhaust from one of the two-7-4897-8690-2133Atty. Dkt. No. 016831-1982 cylinders 13. In some embodiments, the engine assembly 10 includes a catalytic converter 34 arranged upstream of the muffler 32.

[0042] Referring to FIGS. 4-9, the plenum intake assembly 100 includes an air filter 101 (FIGS. 10 and 11), a plenum housing 102 defining an internal volume 110, a throttle body 104 coupled to the plenum housing 102 at a throttle body opening or port 105, a first intake runner or pipe 106 coupled to the plenum housing 102 at a first intake coupling port 112, and a second intake runner 108 coupled to the plenum housing 102 at the second intake coupling port 114. The first intake runner 106 extends between a first cylinder end 118 and a first plenum end 120, and the second intake runner 108 extends between a second cylinder end 122 and a second plenum end 124. In general, the first cylinder end 1 18 and the second cylinder end 122 are both configured to couple to an intake port on an engine (e.g., the engine 12) and supply air from within the internal volume 110 to the engine. For example, the first cylinder end 118 of the first intake runner 106 includes a plurality of cylinder coupling apertures or bosses 107. Each of the cylinder coupling apertures 107 is configured to receive or otherwise accept a fastening element (e.g., a bolt, a screw, etc.) to couple the first cylinder end 118 to the intake port of the engine block 17. Similarly, the second cylinder end 122 of the second intake runner 108 includes a plurality of cylinder coupling apertures or bosses 109. Each of the cylinder coupling apertures 109 is configured to receive or otherwise accept a fastening element (e.g., a bolt, a screw, etc.) to couple the second cylinder end 122 to the intake port of the engine block 17.

[0043] In some embodiments, the plenum housing 102 is fabricated from a plastic material. In some embodiments, the first intake runner 106 and the second intake runner 108 are fabricated from a metal material. In some embodiments, the plenum housing 102 is fabricated from a different material than the first intake runner 106 and the second intake runner 108.

[0044] In some embodiments, when the plenum housing 102 is installed on an engine (e.g., the engine 12 as shown in FIGS. 1-3), the plenum housing 102 is arranged generally above the cylinder 13 and aligned between the cylinder heads 15. In some embodiments, the plenum housing 102 is shaped to fit within a cavity or mounting space on the engine. For example, the plenum housing 102 may include a curved outer wall 113 that is shaped to conform to an outer surface of the blower housing 20. In general, the internal volume 110 is enclosed within the plenum housing 102 (e.g., the walls of the plenum housing 102 are sealed, except for the ports formed therein (e.g., the first-8-4897-8690-2133Atty. Dkt. No. 016831-1982 intake coupling port 112, the second intake coupling port 114, and the throttle body port 105). Accordingly, once the throttle body 104, the first intake runner 106, and the second intake runner 108 are coupled to the plenum housing 102, the internal volume 110 is enclosed, except for the air flow allowed through the throttle body 104, the first intake runner 106, and the second intake runner 108.

[0045] In the illustrated embodiment, the throttle body port 105 is arranged on the same side of the plenum housing 102 as the second intake runner 108. In some embodiments, the throttle body port 105, and the throttle body 104 coupled thereto may be arranged in another location on the plenum housing 102. In operation, the throttle body 104 is positioned upstream of the plenum housing 102 and both the first and second intake runners 106, 108. In other words, air first flows through the throttle body 104, then into the internal volume 110 of the plenum housing 102, and then to the first intake runner 106 and the second intake runner 108. In some embodiments, the throttle body 104 is configured to control or limit air flow into the internal volume 110 of the plenum housing 102 via a valve (e.g., butterfly valve) within the throttle body 104. In this way, for example, the throttle body 104 is configured to control an amount of air, and thereby an airfuel ratio, that is supplied to the intake ports of the engine (e.g., the engine 12).

[0046] The first intake runner 106 defines a first central axis 126 that extends axially along a first passage or channel 128 formed through the first intake runner 106 between the first cylinder end 118 and the first plenum end 120 (see, e.g., FIG. 8). The first passage 128 provides fluid communication between the first plenum end 120 and the first cylinder end 118, which provides fluid communication between the internal volume 110 and the intake port of the engine to which the first cylinder end 118 is coupled (e.g., the engine 12). A length of the first intake runner 106 is defined as a length along the first central axis 126 between the first cylinder end 118 and the first plenum end 120. In general, a length of the first intake runner 106 may be adjusted to vary the volume defined by the first intake runner 106 and the performance of the engine to which the first intake runner 106 is coupled (e.g., intake pressure).

[0047] The first intake runner 106 includes a first coupling flange 130 or coupling plate that extends radially outwardly from an outer surface of the first intake runner 106. The first coupling flange 130 is arranged along the first intake runner 106 in a location that is axially between the first cylinder end 118 and the first plenum end 120. In the illustrated embodiment, the first-9-4897-8690-2133Atty. Dkt. No. 016831-1982 coupling flange 130 includes a plurality of mounting apertures that are each configured to receive a fastening element 132 (e.g., a screw, a bolt, etc.) that extends through the first coupling flange 130 and into a corresponding mounting aperture formed around the first intake coupling port 112. Accordingly, the first intake runner 106 may be a separate component from the plenum housing 102 (e.g., not formed as a unitary component) that is installed on or coupled to the plenum housing 102 via the first intake coupling port 112, the first coupling flange 130, and the fastening elements 132.

[0048] In general, a length or portion of the first intake runner 106 that is arranged between the first coupling flange 130 and the first cylinder end 118 is arranged external to the plenum housing 102, and a length or portion of the first intake runner 106 that is arranged between the first coupling flange 130 and the first plenum end 120 is arranged internal to or within the internal volume 110 of the plenum housing 102. Accordingly, at least a portion of the first intake runner 106 extends into the plenum housing 102 so that the first plenum end 120 is arranged within and enclosed by the internal volume 110 of the plenum housing 102. The first plenum end 120 is arranged within the internal volume 110 so that a length of the first intake runner 106 may be adjusted by lengthening or shortening an extension distance DI defined by the first intake runner 106 (see e.g., FIG. 8). The extension distance DI is defined as a length of the first intake runner 106 extending between an outer wall of the first intake coupling port 112 and the first plenum end 120. As shown in FIGS. 5-8, the first plenum end 120 is arranged within the internal volume 110 of the plenum housing 102 with sufficient clearance so that the extension distance DI may be shortened or lengthened to define a different overall length of the first intake runner 106, which may be required to pressure balance the intake for a particular engine application or operating condition. The shape and length of the first intake runner 106 between the first cylinder end 118 and the first coupling flange 130 may be fixed. Accordingly, if the extension distance DI is changed to vary the overall length of the first intake runner 106, the mounting between the first intake runner 106 and both the plenum housing 102 and the engine does not need to be altered, which allows varying lengths of the first intake runner 106 to be utilized with the plenum intake assembly 100 without requiring changes to the design of the plenum housing 102 or the engine.

[0049] The first plenum end 120 of the first intake runner 106 may define a flared profile such that the diameter of the first plenum end 120 is larger than the diameter of the remainder of the-10-4897-8690-2133Atty. Dkt. No. 016831-1982 first intake runner 106, as shown in FIG. 8. For example, the first plenum end 120 may define a tapered flange that tapers radially outward from the first central axis 126, so that an angle Al is formed between the tapered flange and an outer surface of the first intake runner 106. In some embodiments, the first plenum end 120 may have a straight end such that the diameter of the first plenum end 120 is substantially equal to the diameter of the remainder of the first intake runner 106. In some embodiments, the first plenum end 120 may also have a necked-down profile such that the diameter of the first plenum end 120 is smaller than the diameter of the remainder of the first intake runner 106.

[0050] The second intake runner 108 defines a second central axis 134 that extends axially along a second passage or channel 136 formed through the second intake runner 108 between the second cylinder end 122 and the second plenum end 124 (see, e.g., FIG. 9). The second passage 136 provides fluid communication between the second plenum end 124 and the second cylinder end 122, which provides fluid communication between the internal volume 110 and the intake port of the engine to which the second cylinder end 122 is coupled (e g., the engine 12). A length of the second intake runner 108 is defined as a length along the second central axis 134 between second cylinder end 122 and the second plenum end 124. In general, a length of the second intake runner 108 may be adjusted to vary the volume defined by the second intake runner 108 and the performance of the engine to which the second intake runner 108 is coupled (e.g., intake pressure).

[0051] The second intake runner 108 includes a second coupling flange 138 or coupling plate that extends radially outwardly from an outer surface of the second intake runner 108. The second coupling flange 138 is arranged along the second intake runner 108 in a location that is axially between the second cylinder end 122 and the second plenum end 124. In the illustrated embodiment, the second coupling flange 138 includes a plurality of mounting apertures that are each configured to receive a fastening element 140 (e.g., a screw, a bolt, etc.) that extends through the second coupling flange 138 and into a corresponding mounting aperture formed around the second intake coupling port 114. Accordingly, the second intake runner 108 may be a separate component from the plenum housing 102 (e.g., not formed as a unitary component) that is installed on or coupled to the plenum housing 102 via the second intake coupling port 114, the second coupling flange 138, and the fastening elements 140.-11-4897-8690-2133Atty. Dkt. No. 016831-1982

[0052] In general, a length or portion of the second intake runner 108 that is arranged between the second coupling flange 138 and the second cylinder end 122 is arranged external to the plenum housing 102, and a length or portion of the second intake runner 108 that is arranged between the second coupling flange 138 and the second plenum end 124 is arranged internal to or within the internal volume 110 of the plenum housing 102. Accordingly, at least a portion of the second intake runner 108 extends into the plenum housing 102 so that the second plenum end 124 is arranged within and enclosed by the internal volume 110 of the plenum housing 102. The second plenum end 124 is arranged within the internal volume 110 so that a length of the second intake runner 108 may be adjusted by lengthening or shortening an extension distance D2 defined by the second intake runner 108 (see e.g., FIG. 9). The extension distance D2 is defined as a length of the second intake runner 108 extending between an outer wall of the second intake coupling port 114 and the second plenum end 124. As shown in FIGS. 5-7 and 9, the second plenum end 124 is arranged within the internal volume 110 of the plenum housing 102 with sufficient clearance so that the extension distance D2 may be shortened or lengthened to define a different overall length of the second intake runner 108, which may be required to pressure balance the intake for a particular engine application or operating condition. The shape and length of the second intake runner 108 between the second cylinder end 122 and the second coupling flange 138 may be fixed. Accordingly, if the extension distance D2 is changed to vary the overall length of the second intake runner 108, the mounting between the second intake runner 108 and both the plenum housing 102 and the engine does not need to be altered, which allows varying lengths of the second intake runner 108 to be utilized with the plenum intake assembly 100 without requiring changes to the design of the plenum housing 102 or the engine.

[0053] The second plenum end 124 of the second intake runner 108 may define a flared or tapered profile such that the diameter of the second plenum end 124 is larger than the diameter of the remainder of the second intake runner 108, as shown in FIG. 9. For example, the second plenum end 124 may define a tapered flange that tapers radially outwardly from the second central axis 134, so that an angle A2 is formed between the tapered flange and an outer surface of the second intake runner 108. In some embodiments, the second plenum end 124 may have a straight end such that the diameter of the second plenum end 124 is substantially equal to the diameter of the remainder of the second intake runner 108. In some embodiments, the second plenum end 124-12-4897-8690-2133Atty. Dkt. No. 016831-1982 may have a necked-down profile such that the diameter of the second plenum end 124 is smaller than the diameter of the remainder of the second intake runner 108.

[0054] In some embodiments, the first plenum end 120 and the second plenum end 124 may be arranged at different heights and orientations within the internal volume 110 of the plenum housing 102. For example, the first plenum end 120 may be arranged at a height (e.g., a vertical distance from the perspective of FIGS. 6, 8, and 9) that is greater than a height of the second plenum end 124. In other words, the channel 128 may be arranged at a greater height within the internal volume 110 of the plenum housing 102 than the second central axis 134. Additionally, the first intake runner 106 may be angled relative to the second intake runner 108, so that the first plenum end 120 and second plenum end 124 face in different directions within the internal volume 110 of the plenum housing 102. Specifically, the first intake runner 106 and the second intake runner 108 may extend into the plenum housing 102 so that the first central axis 126 and the second central axis 134 intersect within the internal volume 110 (e.g., upon extending the first central axis 126 and the second central axis 134 beyond the first plenum end 120 and the second plenum end 124, respectively). In general, the arrangement of the first plenum end 120 and the second plenum end 124 at different heights and orientations within the internal volume 110 provides sufficient space within the internal volume 110 so that the extension distance DI and the extension distance D2 may be varied without interference between the first plenum end 120 and the second plenum end 124. Accordingly, the extension distances DI, D2 may be varied within the internal volume 110 of the plenum housing 102 for different applications and engine operating conditions to improve pressure balancing between the different cylinders on the engine (e.g., the engine 12). In this way, for example, the plenum intake assembly 100 may include different lengths for the first intake runner 106 and the second intake runner 108 depending on the particular application that the engine is being used for or installed on (e.g., engine speed and load profiles for a generator are different than a lawn mower). And the lengths of the first intake runner 106 and the second intake runner 108 may be designed to balance (e.g., within a certain tolerance) the intake pressures for these different applications, which reduces engine vibration, increases engine efficiency, and increases engine power output. Depending on the particular engine application, the first intake runner 106 and the second intake runner 108 may be designed to define a length that is approximately equal, the first intake runner 106 may define a length that is longer than the second intake runner 108, or-13-4897-8690-2133Atty. Dkt. No. 016831-1982 the first intake runner 106 may define a length that is shorter than the second intake runner 108. In some embodiments, the extension distance DI is approximately equal to the extension distance D2. In some embodiments, the extension distance DI is different than the extension distance D2 (e.g., the extension distance DI is greater than the extension distance D2, or the extension distance DI is less than the extension distance D2). The specific lengths defined by the first intake runner 106 and the second intake runner 108 will depend on the engine dynamics and intake fluid mechanics for each engine application.

[0055] Turning to FIGS. 10 and 11, the air filter 101 is supported on the plenum housing 102 and includes a cylindrical body and is connected to a filter passage 142. The filter passage 142 extends between the air filter 101 and the throttle body 104, so that filtered air flowing from the air filter 101 is provided to the throttle body 104. In other words, the throttle body 104 is positioned downstream of and is in fluid communication with the air filter 101. In the illustrated embodiment, the plenum housing 102 includes housing protrusions 111 that extend outwardly from an upper surface of the plenum housing 102. Each of the housing protrusions 111 is configured to engage and / or at least partially receive a corresponding filter protrusion 144 that extends outwardly from a lower surface of the air filter 101. In some embodiments, the housing protrusions 111 may each include a threaded hole or bore that is configured to receive a fastening element (e.g., a screw, a bolt, etc.) that extends through an opening formed in the corresponding filter protrusion 144 to secure the air filter 101 to the plenum housing 102.

[0056] During operation, the air filter 101 receives air present in the atmosphere and passes the air through an internal filter element. Then the filtered air is passed from the air filter 101, along the filter passage 142 and downstream to the throttle body 104, which controls or throttles the airflow depending on the engine operating conditions. The air then flows into the internal volume 110 of the plenum housing 102, through the first intake runner 106 and the second intake runner 108, and to the intake ports on the engine.

[0057] Referring now to FIGS. 12-21, the engine assembly 10 is shown according to exemplary embodiment. The engine assembly 10 of FIGS. 12-21 may be substantially similar to the engine assembly 10 of FIGS. 1-11, with like features identified using similar reference numerals, except as shown in the figures or described herein.-14-4897-8690-2133Atty. Dkt. No. 016831-1982

[0058] As shown in FIGS. 15, 16, and 18, the engine assembly 10 includes a fuel pump 152 mounted to the plenum housing 102. The plenum housing 102 includes three bosses 156 with holes or bores (e.g., threaded holes) configured to receive a fastener (e.g., a screw). The fuel pump 152 includes flanges 154 each with an opening (e.g., a through hole) configured to receive the fastener. The fasteners may be passed through the openings in the flanges 154 and secured to the openings in the bosses 156 to secure the fuel pump 152 to the plenum housing 102. In contrast, the engine assembly 10 of FIGS. 1-11 includes the fuel pump mounted to the rear of the engine 12 between the cylinder heads 15. Coupling the fuel pump 152 to the plenum housing 102 as shown in the embodiment of FIGS. 12-21 eliminates the need to provide mounting features for the fuel pump 152 on the engine 12 and may make the engine assembly 10 easier to assemble.

[0059] As shown in FIGS. 13, 15-19, and 21, the first intake runner 106 and the second intake runner 108 of the engine assembly 10 are straight pipes extending from the cylinder heads 15 into the plenum housing 102, rather than the curved intake runners 106, 108 of the embodiment of FIGS. 1-11. For example, the first central axis 126 defined by the first intake runner 106 extends linearly, and the second central axis 134 of the second intake runner 108 extends linearly, which defines a straight profile along the inner passageways defined by the first intake runner 106 and the second intake runner 108. This simplifies both the designs of the intake runners 106, 108 and the assembly and maintenance processes of the engine assembly 10. Further, the straight intake runners 106, 108 improve tumble motion in the cylinders 13, which provides a faster burn rate of the fuel to increase the efficiency and power of the engine assembly 10.

[0060] The intake runners 106, 108 may include circumferential flanges 158 positioned circumferentially around the outside. The plenum housing 102 includes protrusions 160 extending radially inward from the first intake coupling port 112 and the second intake coupling port 114. The intake runners 106, 108 may be inserted into the respective intake coupling port 112, 114 and then rotated such that the protrusions 160 are captured between the respective circumferential flanges 158 and the respective coupling flange 130, 138 (e.g., forming a bayonet coupling). This may eliminate the need for fastening elements 132, 140 and simplify assembly and maintenance processes of the engine assembly 10.

[0061] As in the embodiment of FIGS. 1-11, the intake runners 106, 108 each extend a distance into the plenum housing 102. As shown in FIG. 18, the first intake runner 106 extends a distance-15-4897-8690-2133Atty. Dkt. No. 016831-1982 D3 into the plenum housing 102, and the second intake runner 108 extends a distance D4 into the plenum housing 102. As discussed above, the intake runners 106, 108 may be geometrically tuned to balance the intake pressure from cylinder to cylinder. The volume defined by the plenum housing 102 provides sufficient space so that the first intake runner 106 and the second intake runner 108 may extend into the volume either a similar distance or different distances, depending on the overall length of the intake runner required to pressure balance the intake pressures for a particular engine application and / or operating condition.

[0062] As utilized herein with respect to numerical ranges, the terms “approximately,” “about,” “substantially,” and similar terms generally mean + / - 10% of the disclosed values. When the terms “approximately,” “about,” “substantially,” and similar terms are applied to a structural feature (e.g., to describe its shape, size, orientation, direction, etc.), these terms are meant to cover minor variations in structure that may result from, for example, the manufacturing or assembly process and are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims.

[0063] It should be noted that the term “exemplary” and variations thereof, as used herein to describe various embodiments, are intended to indicate that such embodiments are possible examples, representations, or illustrations of possible embodiments (and such terms are not intended to connote that such embodiments are necessarily extraordinary or superlative examples).

[0064] The term “coupled” and variations thereof, as used herein, means the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent or fixed) or moveable (e g., removable or releasable). Such joining may be achieved with the two members coupled directly to each other, with the two members coupled to each other using a separate intervening member and any additional intermediate members coupled with one another, or with the two members coupled to each other using an intervening member that is integrally formed as a single unitary body with one of the two members. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e.g., “directly-16-4897-8690-2133Atty. Dkt. No. 016831-1982 coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic.

[0065] References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below”) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.

[0066] The hardware and data processing components used to implement the various processes, operations, illustrative logics, logical blocks, modules and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or, any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some embodiments, particular processes and methods may be performed by circuitry that is specific to a given function. The memory (e.g., memory, memory unit, storage device) may include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage) for storing data and / or computer code for completing or facilitating the various processes, layers and modules described in the present disclosure. The memory may be or include volatile memory or non-volatile memory, and may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present disclosure. According to an exemplary embodiment, the memory is communicably connected to the processor via a processing circuit and includes computer code for executing (e.g., by the processing circuit or the processor) the one or more processes described herein.

[0067] The present disclosure contemplates methods, systems and program products on any machine-readable media for accomplishing various operations. The embodiments of the present-17-4897-8690-2133Atty. Dkt. No. 016831-1982 disclosure may be implemented using existing computer processors, or by a special purpose computer processor for an appropriate system, incorporated for this or another purpose, or by a hardwired system. Embodiments within the scope of the present disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer or other machine with a processor. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing machines to perform a certain function or group of functions.

[0068] Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above. Such variation may depend, for example, on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations of the described methods could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps.

[0069] It is important to note that the construction and arrangement of the engine assembly 10 and the plenum intake assembly 100 as shown in the various exemplary embodiments is illustrative only. Additionally, any element disclosed in one embodiment may be incorporated or utilized with any other embodiment disclosed herein. Although only one example of an element from one embodiment that can be incorporated or utilized in another embodiment has been described above, it should be appreciated that other elements of the various embodiments may be incorporated or utilized with any of the other embodiments disclosed herein.-18-4897-8690-2133

Claims

Atty. Dkt. No. 016831-1982WHAT IS CLAIMED IS:

1. An air intake assembly for a small engine, the air intake assembly comprising: a plenum housing defining an internal volume; a first intake runner coupled to the plenum housing and extending between a first cylinder end and a first plenum end, wherein a portion of the first intake runner extends into the plenum housing by a first extension distance so that the first plenum end is arranged within the internal volume; and a second intake runner coupled to the plenum housing and extending between a second cylinder end and a second plenum end, wherein a portion of the second intake runner extends into the plenum housing by a second extension distance so that the second plenum end is arranged within the internal volume.

2. The air intake assembly of claim 1, wherein the first extension distance is approximately equal to the second extension distance.

3. The air intake assembly of claim 1, wherein the first extension distance is different than the second extension distance.

4. The air intake assembly of claim 1, further comprising a throttle body coupled to the plenum housing and in fluid communication with the internal volume.

5. The air intake assembly of claim 1, wherein the plenum housing is fabricated from a plastic material.

6. The air intake assembly of claim 1, wherein the first intake runner includes a first coupling flange that is coupled to the plenum housing and arranged between the first cylinder end and the first plenum end.-19-4897-8690-2133Atty. Dkt. No. 016831-19827. The air intake assembly of claim 6, wherein a portion of the first intake runner arranged between the first cylinder end and the first coupling flange is arranged external to the plenum housing.

8. The air intake assembly of claim 1, wherein the second intake runner includes a second coupling flange that is coupled to the plenum housing and arranged between the second cylinder end and the second plenum end.

9. The air intake assembly of claim 8, wherein a portion of the second intake runner arranged between the second cylinder end and the second coupling flange is arranged external to the plenum housing.

10. The air intake assembly of claim 1, wherein the first intake runner defines an axial length that is approximately equal to an axial length defined by the second intake runner.11 . The air intake assembly of claim 1 , wherein the first intake runner defines an axial length that is different than an axial length defined by the second intake runner.

12. The air intake assembly of claim 1, wherein the first plenum end is arranged at a height within the internal volume that is greater than a height of the second plenum end within the internal volume.

13. The air intake assembly of claim 1, wherein the first intake runner is orientated at an angle relative to the second intake runner so that a first central axis defined by the first intake runner intersects with a second central axis defined by the second intake runner within the internal volume.

14. The air intake assembly of claim 1, further comprising an air filter supported on the plenum housing.-20-4897-8690-2133Atty. Dkt. No. 016831-198215. The air intake assembly of claim 14, further comprising a throttle body coupled to the plenum housing and in fluid communication with the internal volume.

16. The air intake assembly of claim 15, further comprising a filter passage extending between the air filter and the throttle body.

17. The air intake assembly of claim 1, wherein the first intake runner and the second intake runner comprise straight pipes extending into the plenum housing.

18. The air intake assembly of claim 1, further comprising a fuel pump coupled directly to the plenum housing.

19. An engine assembly comprising: an engine block; a crankshaft at least partially arranged within the engine block; a blower assembly coupled to the engine block and configured to provide cooling air to the engine block; and an air intake assembly including: a plenum housing defining an internal volume; a first intake runner coupled to the plenum housing and extending between a first cylinder end and a first plenum end, wherein a portion of the first intake runner extends into the plenum housing by a first extension distance so that the first plenum end is arranged within the internal volume; and a second intake runner coupled to the plenum housing and extending between a second cylinder end and a second plenum end, wherein a portion of the second intake runner extends into the plenum housing by a second extension distance so that the second plenum end is arranged within the internal volume.-21-4897-8690-2133Atty. Dkt. No. 016831-198220. The engine assembly of claim 19, wherein the first extension distance is approximately equal to the second extension distance.

21. The engine assembly of claim 19, wherein the first extension distance is different than the second extension distance.

22. The engine assembly of claim 19, wherein the first intake runner and the second intake runner comprise straight pipes extending into the plenum housing.

23. The engine assembly of claim 19, wherein the first cylinder end of the first intake runner is coupled to a first cylinder head, and the second cylinder end of the second intake runner is coupled to a second cylinder head.

24. The engine assembly of claim 19, wherein the plenum housing is positioned above the engine block and between a first cylinder head and a second cylinder head.

25. The engine assembly of claim 19, wherein the plenum housing includes an outer wall shaped to conform to a surface of a blower housing of the blower assembly.

26. The engine assembly of claim 19, further comprising a fuel pump coupled directly to the plenum housing.

27. A method of assembling an engine assembly, comprising: coupling a first end of first intake runner to a first cylinder head; coupling a first end of second intake runner to a second cylinder head; coupling the first intake runner to a plenum housing with a second end of the first intake runner extending a first distance into the plenum housing; and coupling the second intake runner to the plenum housing with a second end of the second intake runner extending a second distance into the plenum housing.-22-4897-8690-2133Atty. Dkt. No. 016831-198228. The method of claim 27, wherein the first intake runner comprises a coupling flange positioned between the first end of the first intake runner and the second end of the first intake runner, wherein coupling the first intake runner to the plenum housing comprises inserting the second end of the first intake runner into a first intake coupling port of the plenum housing and coupling the coupling flange to the first intake coupling port.

29. The method of claim 27, wherein the first distance is approximately equal to the second distance.

30. The method of claim 27, wherein the first distance is different than the second distance.-23-4897-8690-2133

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