FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
& THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
BREATHER ASSEMBLY WITH STANDPIPE FOR AN INTERNAL COMBUSTION ENGINE;
KOHLER CO., A CORPORATION OF THE STATE OF WISCONSIN LOCATED AT 444 HIGHLAND DRIVE, KOHLER, WISCONSIN 53044, U.S.A..
THE FOLLOWING SPECIFICATION
PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED. 1

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. provisional patent application no. 61/061,388 entitled "Breather assembly with standpipe for an internal combustion engine" filed on June 13, 2008, which is hereby incorporated by reference herein.
FIELD OF THE INVENTION
The present invention relates generally to internal combustion engines and, more particularly, to breather assemblies used in conjunction with internal combustion engines. In one aspect, the present invention relates to internal breather assemblies having a standpipe for use within an internal combustion engine.
BACKGROUND OF THE INVENTION
In internal combustion engines, pistons are housed within corresponding cylinders for reciprocating movement therein. Fuel and air enter a combustion chamber in a cylinder on a first side of a piston. The fuel in the combustion chamber is ignited to cause linear motion of the piston inside the respective cylinder. The linear motion of the piston is then converted to rotary motion by the crankshaft. Ideally, all of the gases in the combustion chamber(s) after ignition of the fuel would be exhausted via an engine exhaust pipe. However, a portion of the exhaust gases typically pass past the piston rings and the cylinder walls of the cylinders housing the pistons to enter the crankcase. These exhaust gases build up in the crankcase thereby pressurizing the crankcase. During routing of the exhaust gases within the crankcase, the gases often become contaminated with oil mist/oil droplets, the mixture of which is known as crankcase blow-by, or simply blow-by.
To relieve such exhaust gases from the crankcase, a breather assembly, joining the crankcase to an air intake point (e.g., an air cleaner or intake manifold), is typically attached to, or incorporated into, the internal combustion engine. A one-way valve is additionally placed inline at an entrance hole between the breather assembly and the crankcase, such that gases

escaped from the crankcase cannot return thereto. Frequently, along with the exhaust gases, some oil mist/oil droplets are invariably expelled into the breather assembly, In at least some conventional breather assemblies, at least some of the oil mist/oil droplets that pass into the breather assembly are trapped therein and tend to flow back into the crankcase due to pressure differentials and gravity via a drainback conduit.
Utility engines with breather assemblies are typically used with small power equipment, such as a lawnmower. In applications such as lawnmowers, the engine is often tilted, as would happen when cutting on a hill. Tilting an engine during operation can allow more blow-by gas that is laden with oil droplets to enter the breather assembly. Typically, for optimal removal of oil droplets from blow-by gas, an engine's breather assembly is distanced vertically upwards as far as possible from the oil reservoir. The substantial distance between the breather assembly and the oil reservoir allows gravity to remove more of the oil particles from the blow-by gas before the blow-by gas enters the breather assembly. Additionally, the distance allows the engine to be tilted off a vertical axis point while in use without significantly increasing the amount of oil droplets in the blow-by gas that enters the breather assembly, and therefore it prevents much of the blow-by gas that is heavily laden with oil droplets from entering the breather assembly and being pulled by engine vacuum or pushed by the crankcase pressure into the air intake point. The intake of substantial oil droplets in the air intake point of an engine results in excessive oil being exhausted to the engine cylinder where it is burned, thereby increasing engine oil consumption and producing excessive smoke.
Due to the particular configurations of horizontal and vertical crankshaft engines and the desire to maintain the breather entrance hole as far above the oil reservoir as possible, varied designs are often required to accommodate the breather assembly placement; this in turn limits the interchangeability among their engine components.
It would therefore be advantageous to provide an improved breather assembly that at least partially reduces the amount of oil droplets introduced into the breather assembly, particularly when an engine is tilted, as can occur during typical engine use. It would further be advantageous if such a breather assembly can provide at least some interchangeability among horizontal and vertical crankshaft engine components.

BRIEF SUMMARY OF THE INVENTION
In one aspect, the present invention relates to a breather assembly that includes an input chamber for receiving blow-by gas, the input chamber bounded at least partially by a crankcase exterior; and a standpipe situated inside the input chamber for directing blow-by gas from a crankcase interior into the input chamber. Alternatively, the input chamber of the breather assembly can be bounded substantially by the crankcase exterior, or the input chamber can have at least two sides formed from the crankcase exterior. Additionally, the breather assembly can include an input drainback passage situated inside the input chamber for draining oil from the input chamber and an output chamber situated adjacent the input chamber, wherein an inner wall is situated between the chambers, the inner wall having a one-way valve that allows blow-by gas to flow from the input chamber to the output chamber. The breather assembly further can include an output drainback aperture situated in the inner wall to provide two-way communication between the output chamber and the input chamber, and an output chamber housing mar substantially- encloses the output chamber and can indude an exhaust port for exhausting blow-by gas. Still further, the breather assembly can include an exhaust tube connecting the exhaust port to an air intake point and a filter media situated in the input chamber.
In another aspect, the present invention relates to an internal combustion engine having a vertically situated crankshaft, a crankcase having a crankcase exterior that at least partially encloses the engine, and an input chamber for receiving blow-by gas bounded at least partially by a portion of the crankcase exterior. Alternatively, the input chamber of the internal combustion engine can be bounded substantially by the crankcase exterior, or the input chamber can have at least two sides formed from the crankcase exterior. The engine can further include a breather assembly having a standpipe situated inside the input chamber for directing blow-by gas into the input chamber. The standpipe in the breather assembly can be positioned parallel or substantially parallel with the crankshaft. Additionally, the breather assembly can include an input chamber sump situated in the input chamber for collecting oil droplets from the blow-by gas, and an input drainback passage that provides communication between the input chamber sump and an oil reservoir in the engine for draining oil. Still fiirther, the breather assembly can include an output chamber housing situated adjacent the input chamber, having an inner wall that at least partially encloses the input chamber and an outer wall interfaced with a perimeter of the inner wall to form an output chamber therein. Yet still further, the breather assembly can include

an output drainback aperture situated in a lower portion of the inner wall to provide communication between the output chamber and the input chamber sump the inner wall including a one-way valve situated above the output drainback that allows blow-by gas to flow from the input chamber to the output chamber, and an exhaust port situated in the outer wall for exhausting blow-by gas. Additionally, the breather assembly can include an exhaust tube connecting the exhaust port to an air intake point and a filter media situated in the intake chamber. Yet further, the input chamber can be substantially bounded by the crankcase exterior, or the input chamber can comprise at least two sides formed from the crankcase exterior. The internal combustion engine can further comprise an oil reservoir situated in the crankcase interior and an input drainback passage providing communication between the input chamber and the crankcase interior. In other embodiments, the internal combustion engine of claim can further comprise a crankcase extension that extends vertically from the crankcase interior into the input chamber, wherein the crankcase extension directs blow-by gas from the crankcase interior into the input chamber. Still further, the crankcase can be.capable of use on a horizontal crankshaft type and/or a vertical crankshaft type internal combustion engine.
In yet another aspect, the present invention relates to a method of operating an internal combustion engine by providing an internal combustion engine comprising: a crankshaft oriented along a vertical axis, a crankcase having an exterior that at least partially surrounds the crankshaft, an oil pan secured to the crankcase, a breather assembly at least partially formed from a crankcase exterior, and a standpipe extending from the crankcase. The method further includes directing the flow of blow-by gas through the standpipe to reduce the flow of oil droplets from the crankcase into the breather assembly when the engine is at least partially tilted off the vertical axis. In alternative embodiments, the breather assembly can be bounded substantially by the crankcase exterior, or the breather assembly can have at least two sides formed from the crankcase exterior. The method can further include (i) providing an oil reservoir having at least one of a portion of the crankcase and a portion of the oil pan, for housing engine oil and receiving oil from the breather assembly; (ii) receiving blow-by gas from the standpipe into an input chamber; (iii) filtering oil droplets from the blow-by gas in the input chamber using a filter and collecting the oil droplets in an input chamber sump; (iv) draining the oil droplets from the input chamber sump to the oil reservoir using an input drainback passage; (v) releasing the blow-by gas from the input chamber through a one-way valve in an inner wall

to an output chamber; (vi) exhausting the blow-by gas from the output chamber to an air intake point; and/or (vii) draining oil droplets accumulated in the output chamber to the input chamber sump through an output drainback passage.
Other embodiments, aspects, features, objectives and advantages of the present invention will be understood and appreciated upon a full reading of the detailed description and the claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
Features of the present invention which are believed to be novel are set forth with particularity in the appended claims. Embodiments of the invention are disclosed with reference to the accompanying drawings and are for illustrative purposes only. The invention is not limited in its application to the details of construction or the arrangement of the components illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in other various ways. Like reference numerals are used to indicate like components. In the drawings:
FIG. 1 is a schematic view of an internal combustion engine having a vertically oriented crankshaft, that includes an exemplary breather assembly in accordance with at least some embodiments of the present invention;
FIG. 2 is a schematic cross-sectional view of a portion of the internal combustion engine taken along line A-A of FIG. 1 depicting the exemplary breather assembly having a standpipe. an oil pan, and a crankcase, in accordance with at least some embodiments of the present invention;
FIG. 3 illustrates an enlarged portion of the schematic cross-sectional view of the breather assembly of section A-A of FIG. 2; and
FIG. 4 is a schematic cross-sectional view showing a portion of an internal combustion engine with a horizontally oriented crankshaft that includes the exemplary crankcase of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Regarding FIG. 1, a perspective view of an internal combustion engine 2 is depicted in accordance with at least some embodiments of the present invention, having a vertical axis 3. The engine 2 includes a vertically oriented crankshaft 4, an exemplary breather assembly 5 (the exterior of which is shown), an oil pan 6, a crankcase 8, and an oil reservoir (not shown). The exemplary breather assembly 5 includes a standpipe that, while not shown in FIG. 1, will be described further below. The breather assembly 5 is intended to be employed within a variety of internal combustion engines serving a variety of applications. For example, in at least some embodiments of the present invention, the breather assembly 5 can be employed with various vertical and horizontal shaft engines, including, by way of example, COMMAND PRO engines available from the Kohler Company of Kohler, Wisconsin, which are typically used in a variety of applications, such as in turf mowers, turf equipment, generators, power trowels and sawmills.
In alternate embodiments, other types of internal combustion engines can be employed. In so far as various structures and components, including for example, carburetors, air filters, intake manifolds and other related parts of a typical internal combustion engine are well known; such components are not illustrated in the figures. It can be noted that the configuration, relative operation and arrangement of the various aforementioned components is readily available and well known in the art. Therefore, for simplicity and conciseness of expression, various other types of internal combustion engines and several related components are not shown or otherwise detailed herein. Nevertheless, such components are contemplated and considered within the scope of the present invention.
Relatedly, various components associated with a conventional breather assembly, such as gaskets, seals and hoses for transporting the blow-by gas and other related structures, are not identified in the figures. Such aforementioned components and the manner of operation thereof are readily available and known to those of skill in the art and the use of such components is contemplated and considered within the scope of the present invention.
FIG. 2 is a schematic cross-section of a portion of the engine 2 that depicts the oil pan 6, the crankcase 8, the oil reservoir 10, and a crankshaft 4. The schematic cross-sectional view is taken along line A-A of FIG. 1 and coincides at least in part with vertical axis 3. The engine 2 further includes the exemplary breather assembly 5 having a standpipe 12. The crankcase 8

WE CLAIM:
1. A breather assembly comprising:
an input chamber for receiving blow-by gas, the input chamber bounded at least partially by a crankcase exterior; and
a standpipe situated inside the input chamber for directing blow-by gas from a crankcase interior into the input chamber.
2. The breather assembly of claim 1, further comprising an input drainback passage situated inside the input chamber for draining oil from the input chamber.
3. The breather assembly of claim 1, further comprising an output chamber situated adjacent the input chamber, wherein an inner wall is situated between the output and input chambers, the inner wall having a one-way valve that allows blow-by gas to Row from the input chamber to the output chamber.
4. The breather assembly of claim 3, further comprising an output drainback aperture situated in the inner wall to provide two-way communication between the output chamber and the input chamber.
5. The breather assembly of claim 4, further comprising an output chamber housing that substantially encloses the output chamber and includes an exhaust port for exhausting blow-by gas.
6. The breather assembly of claim 5, further comprising an exhaust tube connecting the exhaust port to an air intake point.
7. The breather assembly of claim 6, further comprising a filter media situated in the input chamber.
8. The breather assembly of claim 6, wherein the input chamber is substantially bounded by the crankcase exterior.
9. The breather assembly of claim 6, wherein the input chamber has at least two sides formed from the crankcase exterior.

10. An internal combustion engine comprising:
a vertically situated crankshaft;
a breather assembly including an input chamber for receiving blow-by gas and a standpipe situated inside or substantially inside the input chamber for directing blow-by gas into the input chamber; and
a crankcase having a crankcase interior and a crankcase exterior, wherein the crankcase exterior at least partially encloses the engine and at least partially bounds the input chamber.
11. The internal combustion engine of claim 10, wherein the standpipe is situated parallel or substantially parallel with the crankshaft.
12. The internal combustion engine of claim 10, wherein the input chamber includes an input chamber sump for collecting oil droplets from the blow-by gas and an input drainback passage that provides communication between the input chamber sump and an oil reservoir in the engine for draining oil.
13. The internal combustion engine of claim 12, further including an output chamber housing situated adjacent the input chamber, having an inner wall that at least partially encloses the input chamber, and an outer wall interfaced with a perimeter of the inner wall to form an output chamber therein.
14. The internal combustion engine of claim 13, further including an output drainback aperture situated in a lower portion of the inner wall to provide communication between the output chamber and the input chamber sump.
15. The internal combustion engine of claim 14, further including a one-way valve situated in the inner wall above the output drainback, that allows blow-by gas to flow from the input chamber to the output chamber, and an exhaust port situated in the outer wall for exhausting the blow-by gas.
16. The internal combustion engine of claim 15, further including an exhaust tube connecting the exhaust port to an air intake point.
17. The internal combustion engine of claim 16, further including a filter media situated in the input chamber.

18. The internal combustion engine of claim 10, wherein the input chamber is substantially bounded by the crankcase exterior.
19. The internal combustion engine of claim 10, wherein the input chamber has at least two sides formed from the crankcase exterior.
20. The internal combustion engine of claim 10, further comprising an oil reservoir situated in the crankcase interior and an input drainback passage providing communication between the input chamber and the crankcase interior.
21. The internal combustion engine of claim 10, further comprising a crankcase extension that extends vertically from the crankcase interior into the input chamber, wherein the crankcase extension directs blow-by gas from the crankcase interior into the input chamber.
22. The internal combustion engine of claim 10, wherein the crankcase is capable of use on a horizontal crankshaft type and/or a vertical crankshaft type internal combustion engine.
23. A method of operating an internal combustion engine comprising:
providing an internal combustion engine comprising: a crankshaft oriented along a vertical axis, a crankcase having an exterior that at least partially surrounds the crankshaft, an oil pan secured to the crankcase, a breather assembly at least partially formed from a crankcase exterior, and a standpipe extending from the crankcase; and
directing the flow of blow-by gas through the standpipe to reduce the flow of oil droplets from the crankcase into the breather assembly when the engine is at least partially tilted off the vertical axis.
24. The method of claim 23, wherein providing further an oil reservoir comprising at least one of a portion of a crankcase interior and a portion of the oil pan, and using the oil reservoir for housing engine oil and receiving oil from the breather assembly.
25. The method of claim 23, further comprising receiving blow-by gas from the standpipe into an input chamber.
26. The method of claim 25, further comprising filtering oil droplets from the blow-by gas in the input chamber using a filter and collecting the oil droplets in an input chamber sump.

27. The method of claim 26, further comprising draining the oil droplets from the input
chamber sump to the oil reservoir using an input drainback passage.
28. The method of claim 23, further comprising releasing the blow-by gas from the input chamber through a one-way valve in an inner wall to an output chamber.
29. The method of claim 28, further comprising exhausting the blow-by gas from the output chamber to an air intake point.
30. The method of claim 29, further comprising draining oil droplets accumulated in the output chamber to the input chamber sump through an output drainback passage.