US20140290634A1

US20140290634A1 - Crankcase breather

Info

Publication number: US20140290634A1
Application number: US13/854,982
Authority: US
Inventors: Seth E. Slaughter; Jason R. Dare
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2013-04-02
Filing date: 2013-04-02
Publication date: 2014-10-02

Abstract

A crankcase ventilation system for an internal combustion engine having a cylinder block that at least partially defines at least one cylinder includes a valve cover configured to be mounted on an individual cylinder head corresponding to an individual cylinder and form a cavity therein. Further a crankcase ventilation opening associated with the valve cover. A crankcase breather incorporated into the valve cover. The crankcase breather includes a breather body, an inlet portion in fluid communication with the cavity of the valve cover, and an outlet portion aligning with the crankcase ventilation opening of the valve cover.

Description

TECHNICAL FIELD

The present disclosure relates to a crankcase ventilation system for an internal combustion engine, and more particularly to a crankcase breather used in the crankcase ventilation system.

BACKGROUND

During an engine operation, some combustion gases, generally referred to as crankcase gases or blow-by gases, may leak from an engine cylinder into a crankcase. The crankcase gases may increase pressure in the crankcase and also mix with oil particles present in the crankcase. To relieve the pressure in the crankcase, the crankcase gases are typically vented out of the crankcase, e.g., to the atmosphere or recirculated using a crankcase ventilation system. Government regulations relating to environmental concerns have mandated engine manufacturers for heavy duty utilities to use engines with the crankcase ventilation system. Such crankcase ventilation system may employ an engine crankcase breather for segregating the oil particles present in the gases, before being released into the atmosphere or recirculated.
U.S. Pat. No. 8,156,926 discloses a filtration system. The filtration system includes a valve lid defining a chamber. The chamber is configured to extend substantially in a second direction. The filtration system also includes a filter element associated with a lower portion of the chamber. The filtration system further includes a passageway in flow communication with the lower portion of the chamber. The passageway is configured to provide flow communication for a mixture of oil vapor and crankcase fumes flowing into the chamber substantially in a first direction and substantially upward direction. The first direction is generally orthogonal to the second direction. The chamber is configured such that the flow of the mixture into the chamber results in at least a portion of the oil vapor collecting in the filter element, and at least a portion of the crankcase fumes flowing through the filter element.

SUMMARY

In an aspect, the present disclosure provides a crankcase breather incorporated into an individual valve cover for an individual cylinder. The valve cover forming a cavity and having a crankcase ventilation opening associated with the valve cover. The crankcase breather incorporated into the individual valve cover includes a breather body, an inlet portion configured to be in fluid communication with the cavity of the valve cover, and an outlet portion configured to be aligned with the crankcase ventilation opening of the valve cover.
In another aspect, the present disclosure provides a crankcase ventilation system for an internal combustion engine having a cylinder block that at least partially defines at least one cylinder includes the valve cover configured to be mounted on an individual cylinder head corresponding to an individual cylinder. The valve cover forming a cavity therein and the crankcase breather incorporated into the valve cover.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an engine;

FIG. 2 illustrates an exploded view of a valve cover and a crankcase breather;

FIG. 3 illustrates a sectional view of the valve cover with the crankcase breather;

FIG. 4 illustrates a detailed view of an inlet portion of the crankcase breather; and

FIG. 5 illustrates a bottom view of the crankcase breather.

DETAILED DESCRIPTION

The present disclosure relates to a crankcase breather used in the crankcase ventilation system for an internal combustion engine. FIG. 1 illustrates an internal combustion engine 100, such as, a compression ignition engine.
Alternatively, the engine 100 may be a spark ignition engine or a natural gas engine of any size, with any number of cylinders, and in any configuration (“V,” in-line, radial, etc.). Further, the internal combustion engine 100 may operate using a variety of fuels, for example, but not limited to, gasoline, diesel, methane, propane or any other fuels known in the art. The internal combustion engine 100 may include a cylinder block 102 that at least partially defines at least one cylinder 104 housing a reciprocating piston (not shown). The internal combustion engine 100 may further include a crankshaft operably coupled to the pistons, such that reciprocation of the pistons within the cylinders 104 serves to rotate the crankshaft. The crankshaft may be housed within a crankcase 106 defined, for example, by a lower portion of the cylinder block 102 and an oil sump 108. The crankcase 106 may be adequately sealed from the surrounding atmosphere to prevent vapor from the engine 100 being expelled directly into the atmosphere.
According to an exemplary embodiment of the present disclosure, a crankcase ventilation system 110 is provided for the internal combustion engine 100. The crankcase ventilation system 110 relieves the pressure in the crankcase 106 due to the crankcase gases or “blow-by gases”. The crankcase gases may include soot, unburned fuel, exhaust gases, and/or water vapor. The crankcase ventilation system 110 is a closed-loop crankcase ventilation system and may include one or more valve covers 112 mounted on an individual cylinder head 113 corresponding to the cylinder of the at least one cylinder 104 and configured to surround and protects inlet and exhaust valves, an upper part of a push rod, a rocker arm, a fuel injection valve, and the like. Thus crankcase gases may be relieved from the crankcase 106 by way of the valve cover 112, which may further route the crankcase gases towards an oil separator 114, such as a cyclonic separator, to separate oil vapor from the crankcase gases via an inlet hose 116. The oil separator 114 may be connected to an air intake unit 118, such as an air cleaner, and the oil sump 108 via a disposal hose 120 and a drain line 122, respectively. As it will be apparent to a person having ordinary skill in the art that, the oil separator 114 decrease an amount of oil entering the air intake unit 118.
According to an aspect of the present disclosure, a crankcase breather 124 is incorporated into the valve cover 112 for the individual cylinder 104 which will be explained in detail in conjunction with FIGS. 2-5. The crankcase breather 124 is configured to provide a release path for the crankcase gases and acts as a pre-oil separator before routing the crankcase gases into the oil separator 114.
FIG. 2 illustrates an exploded view of the valve cover 112 and the crankcase breather 124. According to an embodiment of the present disclosure, the valve cover 112 includes a body 126 that is formed of an inverted cup-shaped with a top wall 128, a pair of side walls 130, 132, and a pair of end walls 134, 136. The pair of side walls 130, 132 and the end walls 134, 136 extend from the top wall 128 and joined to form a cavity 138. The cavity 138 may be in communication with the crankcase 106 via openings in the cylinder head 113 and the cylinder block 102. In an embodiment, the pairs of side walls 130, 132 and the end walls 134, 136 are stamped from a single sheet of metal. Alternatively, the valve cover 112 may be manufactured by a plastic molding .process. Two peripheral ledges 140 (only one side is shown in FIG. 2) may extend from each of the side walls 130, 132 and which are bounded by perimetric flanges 142. The peripheral ledges 140 are substantially perpendicular to the side walls 130, 132, while the perimetric flanges 142 are substantially parallel to the side wall 130, 132. Further, a row of one or more through holes 141 is provided on the peripheral ledges 140 and configured to receive fastening members 142 to mount the valve cover 112 on the cylinder head 113. For example, as illustrated in FIG. 2, the fastening members 142 may be bolts. Alternatively, the fastening member 142 may be a screw, a rivet, a pin, and/or any appropriate fastener for sealingly coupling the valve cover 112 to the cylinder head 113. Furthermore, a seal or gasket (not shown) made of, for example, silicon rubber, is provided between the valve cover 112 and the cylinder head 113 to provide both effective sealing and noise-damping. In an embodiment, the body 126 of the valve cover 112 may include a first recess 144 and a second recess 146 located along each of the side walls 130, 132. The first recess 144 and/or the second recess 146 may be configured to provide clearance for fastening members 142 such that the body 126 does not interfere while installing the fastening members 142. Alternatively, the size and number of recess, such as 144, 146, may depend on the design and size requirements of the valve cover 112.
According to an embodiment of the present disclosure, the top wall 128 of the valve cover 112 may include a crankcase ventilation opening 148 associated with the valve cover 112 and in communication with the cavity 138 of the valve cover 112. The crankcase breather 124 may include an inlet portion 150 and an outlet portion 152. Upon installation the inlet portion 150 is in fluid communication with the cavity 138 and the outlet portion 152 of the crankcase breather 124 is configured to align with the crankcase ventilation opening 148 of the valve cover 112 and receive the inlet hose 116. The inlet hose 116 may be sealingly secured into the outlet portion 152 using a threaded adapter 154 and an O-ring seal 156. The threaded adapter 154 is retained within the crankcase ventilation opening 148 which is provided with complementary internal threads. Alternatively, various other known means may be used to sealingly secure the inlet hose 116 with the outlet portion 152 of the crankcase breather 124.
According to an embodiment of the present disclosure, the crankcase breather 124 may include a breather body 158 and a bottom plate 160. The breather body 158 may have a two-box form with a breather top wall 162, a first pair of breather side walls 164, and a second pair of breather side walls 166. The first and second pair of breather side walls 164, 166 may extend from the breather top wall 162 and stamped from a single sheet of metal. The first pair of breather side walls 164 are spaced apart by a first distance D1 larger than a second distance D2 between the second pair of breather side walls 166. A breather peripheral ledge 168 may extend from the first and second pair of breather side walls 164, 166. The breather peripheral ledges 168 is coupled to the bottom plate 160 using a stable means, such as rivets 169 or adhesive or welding or brazing, to define a filtration chamber, such that the first pair of breather side walls 164 and the bottom plate 160 define a first filtration chamber 170 and the second pair of breather side walls 166 and the bottom plate 160 define a second filtration chamber 172 (a portion of the breather top wall 162 is removed to show the second filtration chamber 172). The bottom plate 160 may include ear portions, such as a first and second ear portions 173 extending beyond the inlet portion 150 of the crankcase breather 124 to define inlet zones 175 within the cavity 138 of the valve cover 112. Further, the bottom plate 160 may include apertures 174 which are configured to receive fastening members 176 to secure the crankcase breather 124 within the cavity 138 of the valve cover 112.
FIG. 3 illustrates a sectional view of the valve cover 112 with the crankcase breather 124. As illustrated, a first filter element 177 and a second filter element 178 may be disposed within the first and second filtration chambers 170, 172, respectively. The first and second filter elements 177, 178 may be formed from any appropriate filter material, for example, such that at least a portion of oil vapor may be separated from crankcase gases (shown by arrow heads). The filter elements 177, 178 may include a cross-section that may be in the form of a mesh or a web such as a crushed aluminum filtration material. As illustrated, a gap 179 is provided between the first and second filter elements 177, 178 to lower a pressure drop through the first and second filter elements 177 and increase the ability to separate oil vapor from the crankcase gases. In an embodiment, an arrangement of the filter elements 177, 178 is set at a 45 degrees from a vertical and a horizontal direction of flow of the crankcase gases.
FIGS. 4 and 5 illustrate a detailed view of the inlet portion 150 and a bottom view of the crankcase breather 124, respectively. As illustrated in FIG. 4, the bottom plate 160 may be provided with one or more troughs 180 disposed upstream of the first filter element 177 to collect the oil vapor droplets. Further, one or more drain holes 182 may be provided in the troughs 180 to direct the oil vapor droplets to flow in a substantially downward direction. Although, a single row of the troughs 180 is illustrated in FIG. 4, in various other embodiments multiple rows of the troughs 180 may be provided upstream to the first and/or second filter elements 177, 178. Moreover, in an alternative embodiment one or more baffle may be provided in the inlet portion 150 to achieve effective distribution of the crankcase gases and oil vapor separation before passing though the filter elements 177, 178. As illustrated in FIG. 5, the bottom plate 160 is provided with a plurality of drain holes 184 positioned below the first and second filter elements 177, 178.

INDUSTRIAL APPLICABILITY

The industrial applicability of the crankcase breather 124 will be readily appreciated from the foregoing discussion. During the operation of the internal combustion engine 110, the crankcase gases get collected in the cavity 138 of the valve cover 112 and travel through a two-stage filtration via the filter elements 177, 178 and enter the oil separator 114 provide substantially oil-free crankcase gases at the air intake unit 118.
The crankcase ventilation system 110 using the crankcase breather 124 incorporated within the valve cover 112 for individual cylinder 104 acts as a pre-oil separator before routing the crankcase gases into the oil separator 114. Further, the crankcase breather 124 disposed within the valve cover 112 may provide substantial space claim for positioning the oil separator 114 and associated mounting means on the internal combustion engine 100. Moreover, the presence two filter elements 177, 178 provide and additional filtration before the crankcase gases enter the oil separator 114. In addition to that the sloped troughs 180 with drain holes 182 upstream of the filter elements 177, 178 allow the oil vapor to get collected and drain downwards under the action of gravity.
The inlet zones 175 only allows substantially unobstructed flow of the crankcase gases through the crankcase breather 124 may limit the requirements of crankcase breathers 124 to a less number in the internal combustion engine 100 and effectively relive the pressure in the crankcase 106.
Although the embodiments of this disclosure as described herein may be incorporated without departing from the scope of the following claims, it will be apparent to those skilled in the art that various modifications and variations can be made. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.

Claims

What is claimed is:

1. A crankcase breather incorporated into an individual valve cover for an individual cylinder, the valve cover forming a cavity and having an crankcase ventilation opening associated with the valve cover, the crankcase breather comprising:

a breather body;

an inlet portion configured to be in fluid communication with the cavity of the valve cover; and

an outlet portion configured to be aligned with the crankcase ventilation opening of the valve cover.

2. The crankcase breather of claim 1, wherein the breather body includes:

a breather top wall;

a first pair of breather side walls extending from the breather top wall, the first pair of breather side walls are spaced apart by a first distance;

a second pair of breather side walls extending from the breather top wall, the second pair of breather side walls are spaced apart by a second distance lesser than the first distance; and

a breather peripheral ledge extending from the first and second pair of breather side walls.

3. The crankcase breather of claim 2, wherein the crankcase breather further includes a bottom plate coupled to the breather peripheral ledge, and the first pair of breather side walls and the bottom plate define a first filtration chamber and the second pair of breather side walls and the bottom plate define a second filtration chamber.

4. The crankcase breather of claim 3, wherein the first filtration chamber and the second filtration chamber house a first filter element and a second filter element, respectively.

5. The crankcase breather of claim 4, wherein the bottom plate includes one or more troughs disposed upstream of the first filter element and one or more drain holes are provided in the troughs.

6. The crankcase breather of claim 5, wherein the bottom plate includes one or more ear portions extending beyond the inlet portion of the crankcase breather and configured to define an inlet zone within the cavity of the valve cover.

7. A crankcase ventilation system for an internal combustion engine having a cylinder block that at least partially defines at least one cylinder, the crankcase ventilation system comprising:

a valve cover configured to be mounted on an individual cylinder head corresponding to an individual cylinder, the valve cover forming a cavity therein;

a crankcase ventilation opening associated with the valve cover; and

a crankcase breather incorporated into the valve cover, the crankcase breather including:

a breather body;

an inlet portion in fluid communication with the cavity of the valve cover; and

an outlet portion aligned with the crankcase ventilation opening of the valve cover.

8. The crankcase ventilation system of claim 7, wherein the breather body includes:

a breather top wall;

a first pair of breather side walls extending from the breather top wall, the first pair of breather side walls being spaced apart by a first distance;

9. The crankcase ventilation system of claim 8, wherein the crankcase breather further includes a bottom plate coupled to the breather peripheral ledge, and the first pair of breather side walls and the bottom plate define a first filtration chamber and the second pair of breather side walls and the bottom plate define a second filtration chamber having a second volume less than the first volume.

10. The crankcase ventilation system of claim 9, wherein the first filtration chamber and the second filtration chamber house a first filter element and a second filter element, respectively.

11. The crankcase ventilation system of claim 10, wherein the bottom plate includes one or more troughs disposed upstream of the first filter element and one or more drain holes are provided in the troughs.

12. The crankcase ventilation system of claim 9, wherein the bottom plate includes one or more ear portions extending beyond the inlet portion of the crankcase breather to define an inlet zone within the cavity of the valve cover.

13. The crankcase ventilation system of claim 7, wherein the valve cover includes:

a body with a top wall;

a pair of side walls and end walls extending from the top wall, wherein the pair of side walls and end walls are joined to form the cavity;

a peripheral ledge extending from each of the side walls; and

one or more through holes provided on the peripheral ledge and configured to receive fastening members to mount the valve cover on the individual cylinder head.

14. An internal combustion engine comprising:

a cylinder block that at least partially defines at least one cylinder; and

crankcase ventilation system for the internal combustion engine, the crankcase ventilation system including:

an crankcase ventilation opening associated with the valve cover; and

a breather body;

an inlet portion in fluid communication with the cavity of the valve cover; and

an outlet portion aligning with the crankcase ventilation opening of the valve cover.

15. The internal combustion engine of claim 14, wherein the breather body includes:

a breather top wall;

16. The internal combustion engine of claim 15, wherein the crankcase breather further includes a bottom plate coupled to the breather peripheral ledge, and the first pair of breather side walls and the bottom plate define a first filtration chamber and the second pair of breather side walls and the bottom plate define a second filtration chamber having a second volume less than the first volume.

17. The internal combustion engine of claim 16, wherein the first filtration chamber and the second filtration chamber house a first filter element and a second filter element, respectively.

18. The internal combustion engine of claim 17, wherein the bottom plate includes one or more troughs disposed upstream of the first filter element and one or more drain holes are provided in the troughs.

19. The internal combustion engine of claim 14, wherein the valve cover includes:

a body with a top wall;

a pair of side walls and a pair of end walls extending from the top wall, wherein the pair of side walls and end walls are joined to form the cavity;

a peripheral ledge extending from each of the side walls; and

20. The internal combustion engine of claim 14, wherein the crankcase ventilation system further comprises an oil separator.