WO2005103638A1

WO2005103638A1 - Pressure indicator, closed crankcase system, and methods

Info

Publication number: WO2005103638A1
Application number: PCT/US2004/011398
Authority: WO
Inventors: Marty A. Barris
Original assignee: Donaldson Company, Inc.
Priority date: 2004-04-13
Filing date: 2004-04-13
Publication date: 2005-11-03

Abstract

A pressure indicator includes a housing and a diaphragm held by the housing. The diaphragm has a diaphragm surrounding wall defining an interior, an open end, and a closed end. The closed end has a first side, an opposite second side, and a center apex. The first side is in communication with the interior of the diaphragm surrounding wall. The diaphragm is deflectable between a first position and a tripped position and between the tripped position and the first position. The diaphragm is moveable from the tripped position to the first position in response to physical, manual contact by a pushing member on the first side of the closed end of the diaphragm. A closed engine crankcase system includes an air filter, an engine in gas flow communication with the air filter, a blow-by filtration system downstream of and in fluid communication with the engine crankcase, and a pressure indicator in gas flow communication with the engine crankcase and upstream of the blow-by filtration system. The pressure indicator includes a housing and a diaphragm held by the housing. The diaphragm is moveable from a first position to a tripped position in response to pressure downstream of the engine crankcase. A method of indicating pressure in an engine crankcase includes moving a diaphragm in a pressure indicator from a first position to a tripped position when pressure in flow communication with the engine crankcase exceeds a predetermined amount. The method also includes resetting the pressure indicator by accessing the diaphragm from an atmospheric side of the pressure indicator and manually pushing the diaphragm from the tripped position to the first position.

Description

PRESSURE INDICATOR. CLOSED CRANKCASE SYSTEM, AND METHODS

TECHNICAL FIELD This disclosure relates to apparatus and methods for indicating pressure in a closed engine crankcase system. BACKGROUND Some engine crankcase systems are closed for pollution control reasons. In engines, blow-by fluids are created by pressure leakage passed piston rings and by reciprocating motion of pistons. A draft tube from the crankcase emits blow-by in the form of aerosol and coalescence droplets. Chemically, these blow-by emissions are in the form of oil droplets, carbon soot, and debris from wear for fugitive dust. Closed crankcase systems can use a filtration system to clean the blow-by emissions. In some situations, the filtration system can become plugged, causing the crankcase pressure to rise. It would be useful to have a convenient, easily useable, and easily re- settable indicator to communicate when the crankcase pressure has exceeded a certain threshold, so that the filtration system can be serviced.

SUMMARY A pressure indicator is provided. The pressure indicator includes a housing and a diaphragm. The diaphragm is held by the housing. The diaphragm has a diaphragm surrounding wall defining an interior, an open end, and a closed end. The closed end has a first side, an opposite second side, and a center apex. The first side is in communication with the interior of the diaphragm surrounding wall. The diaphragm is deflectable between a first position and a tripped position and between the tripped position and the first position. The diaphragm is moveable from the tripped position to the first position in response to physical, manual contact by a pushing member on the first side of the closed end of the diaphragm. The first position includes the apex projecting outwardly away from the diaphragm surrounding wall, and the tripped position includes the apex being inverted and located within the diaphragm surrounding wall. In another aspect, a closed engine crankcase system is provided. The system includes an air filter, an engine in gas flow communication with the air filter, a blow-by filtration system downstream of and in fluid communication with the engine crankcase, and a pressure indicator in gas flow communication with the engine crankcase and upstream of the blow-by filtration system. The pressure indicator includes a housing and a diaphragm held by the housing. The diaphragm is moveable from a first position to a tripped position in response to pressure downstream of the engine crankcase. In another aspect, a method of indicating pressure in an engine crankcase is provided. The method includes moving a diaphragm in a pressure indicator from a first position to a tripped position when pressure in flow communication with the engine crankcase exceeds a predetermined amount. The method also includes resetting the pressure indicator by accessing the diaphragm from an atmospheric side of the pressure indicator and manually pushing the diaphragm from the tripped position to the first position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic depiction of a closed engine crankcase system, constructed according to principles of this disclosure; FIG. 2 is a side elevational view of a first embodiment of a pressure indicator, constructed according to principles of this disclosure; FIG. 3 is a top plan view of the pressure indicator of FIG. 2; FIG. 4 is a cross-sectional view of the pressure indicator depicted in FIG. 3, the cross-section being taken along the line 4-4 of FIG. 3; FIG. 5 is a top plan view of a diaphragm used in the pressure indicator of FIGS. 2-4; FIG. 6 is a cross-sectional view of the diaphragm depicted in FIG. 5, the cross-section being taken along the line 6-6 of FIG. 5; FIG. 7 is a cross-sectional view of the diaphragm depicted in FIG. 5, the cross-section being taken along the line 7-7 of FIG. 5; FIG. 8 is an enlarged, cross-sectional, fragmented view of a portion of the diaphragm depicted in FIGS. 5-7; FIG. 9 is a cross-sectional view of one embodiment of a blow-by filtration system utilized in the closed engine crankcase system depicted in FIG. 1; FIG. 10 is a schematic, cross-sectional view of a second embodiment of a pressure indicator, constructed according to principles of this disclosure; and FIG. 11 is a schematic, cross-sectional view of the embodiment of the pressure indicator depicted in FIG. 10, and shown in the tripped position.

DETAILED DESCRIPTION

Internal combustion engines, such as pressure-charged diesel engines, often generate "blow-by" gases or fluid, i.e., a flow of air-fuel mixture leaking past pistons from the combustion chambers. Such "blow-by fluid" generally comprise a gas phase, for example air or combustion off gases, carrying therein: (a) hydrophobic fluid (e.g., oil including fuel aerosol) principally comprising 0.1-5.0 micron droplets (principally, by number); and, (b) carbon contaminant from combustion, typically comprising carbon particles, a majority of which are about 0.1-10 microns in size. Such "blow-by fluids" are generally directed outwardly from the engine block, through a blow-by vent. The blow by fluids may carry substantial amounts of other components. Such components may include, for example, copper, lead, silicone, aluminum, iron, chromium, sodium, molybdenum, tin, and other heavy metals. Engines operating in such systems as trucks, farm machinery, boats, buses, and other systems generally comprising diesel engines, may have significant gas flows contaminated as described above. For example, flow rates and volumes on the order of 2-50 cubic feet per minute (cfm), typically 5 to 10 cfm, are fairly common. FIG. 1 illustrates a schematic indicating a typical closed crankcase system 28 in which a pressure indicator according to the present invention would be utilized. Referring to FIG. 1, block 30 represents an internal combustion engine, for example, a turbocharged diesel engine crankcase. Air is taken to the engine 30 through an air filter 32. Air filter or cleaner 32 cleans the air taken in from the atmosphere. A turbo 34 draws the clean air from the air filter 32 and pushes it through an after-cooler 33 into engine crankcase 30. While in engine 30, the air undergoes compression and combustion by engaging with pistons and fuel. During the combustion process, the engine 30 gives off blow-by fluid 38. A filtration system 36 is in gas flow communication with engine 30 and cleans the blow-by fluid 38. From filter system 36, the air is directed through a regulator valve 40. From there, the air is again pulled through by the turbo 34 and into the engine 30. Regulator valve 40 regulates the amount of pressure in the engine crankcase 30. Regulator valve 40 opens more and more, as the pressure in the engine crankcase increases, in order to try to decrease the pressure to an optimal level. The regulator valve 40 closes to a smaller amount when it is desirable to increase the pressure within the engine 30. When air intake system vacuum increases, the regulator valve 40 closes to prevent the crankcase 30 from reaching larger negative pressures. The regulator valve 40 automatically adjusts crankcase pressures as the air filter loads and increases the intake system vacuum, and as the blow-by filtration system 36 loads with contaminant and increases the crankcase pressure. When the pressure exceeds a certain amount in the engine crankcase 30, it is useful to know so that the filtration system 36 can be serviced. A pressure indicator 50 is provided to give a signal or indication when the crankcase pressure has exceeded a predetermined amount. Attention is directed to FIGS. 2-4 and FIGS. 10 and 11. One embodiment of pressure indicator 50 is illustrated in FIGS. 2 - 4, and a second embodiment in FIGS. 10 and 11. In general, the pressure indicator 50 has a diaphragm 52. The diaphragm 52 is for reacting to the varying pressure within the crankcase 30. In specific applications, the diaphragm 52 is for providing a signal when the pressure in the crankcase 30 has exceeded some predetermined point. One particular type of diaphragm 52 is a disc 54. The disc 54 shown in the drawings has these features. The disk 54 is thin and flexible. The thickness of the disc 54 and the material of the disc 54 is selected in order to set the predetermined pressure point at which the diaphragm 54 will provide its visual indication that the crankcase pressure has exceeded a certain amount. In one specific embodiment, the disc 54 is made of reaction injection molded silicone. A suitable thickness is selected to achieve the change in visual indication when the pressure in the crankcase 30 exceeds 10 inches of water. In one specific example, the thickness of the disc 54 will be less than 0.9 mm., typically less than 0.8 mm. In some cases, the thickness will be less than 0.75 mm. The disc 54 has a first side 56 and an opposite second side 58. As will be explained further below, in preferred implementations, the first side 56 will be exposed to the atmosphere and easily accessible for servicing, while the second side 58 will be exposed to the crankcase pressure. In the embodiments depicted in FIGS. 2 - 8 and 10 and 11, the diaphragm 52 includes a diaphragm surrounding wall 128 forming an enclosure 150 (as shown, a cylinder) defining an interior 129, a mouth or open end 130, and a base or closed end 131. The closed end 131 defines the disc 54. The closed end 131 has first side 56, corresponding to the atmospheric side, and opposite side 58 corresponding to the crankcase pressure side. The first side 56 is in communication with the interior 129 of the diaphragm surrounding wall 128. The diaphragm 52 has a center apex 74. Surrounding the mouth 130 is a rim 89. The rim 89 can be used for anchoring the diaphragm 52 within the housing 60 (FIG. 4). The closed end 131 and the surrounding wall 128 preferably have a smooth transition corner 85 (FIG. 8). The transition corner 85 forms the intersection between the deflectable closed end 131 and the surrounding wall 128. In general, the pressure indicator 50 includes a holder or housing 60. The housing 60 is for holding the diaphragm 52. In the embodiment shown, the housing 60 includes a surrounding wall 62 forming a tube 64 defining an open interior 66. The wall 62 defines an open aperture 68 at one end of the tube 64, and in the embodiment of FIGS. 2 - 8, an access opening 70 at the opposite end of the tube 64. The embodiment of FIGS. 10 and 11 does not have an access opening, but instead, has a porous cover 138. The diaphragm 52 is held by the housing 60 over the aperture 68. A ring member 72 can be used to mechanically engage the wall 62, in the embodiment shown, in a snap-engagement 73 to trap the diaphragm 52 in operable position over the aperture 68. If a ring member 72 is used, the access opening 70 is defined by both the housing 60 and the ring member 72. The diaphragm 52 is positioned over the aperture 68 in the housing

60 in such a manner that, in use, the diaphragm is moveable between a first position, FIGS. 2, 3 and 10, and a tripped position, FIGS. 5-7 in phantom in FIG. 4, and FIG. 11. Analogously, the diaphragm 52 is also moveable between the tripped position, FIGS. 5-7 and FIG. 11, to the first position, FIGS. 2, 3, and 10. By "tripped position," it is meant the position that the diaphragm 52 is in after the pressure within the crankcase 30 has exceeded the predetermined amount. In normal operation, the pressure indicator 50 is installed in the closed engine crankcase system. In FIG. 1, it can be seen that the indicator 50 is installed upstream of the blow-by filtration system 36. When installed in this location, the pressure indicator 50 will detect pressure in the crankcase 30. When the filtration system 36 starts to become plugged and restriction across the filter increases, the pressure in the crankcase 30 will rise. This rise in pressure will be felt by the diaphragm 52. When the pressure exceeds a certain amount, the diaphragm 52 will move from the first position, FIGS. 2 and 10, to the tripped position, FIGS. 6 and 11. As can be seen by comparing FIGS. 2 to 6 and FIGS. 10 to 11, the first position can be viewed as a convex, undeflected position of the diaphragm 52. In the embodiment shown, the diaphragm 52 forms a bulbous, hemispherical shape that is extending toward the direction of the engine crankcase 30. The second side 58 of the diaphragm 52 is also a crankcase pressure side because it is exposed to the crankcase pressure. The opposite, first side 56 is an atmospheric side because it is exposed to the atmospheric pressure. When the pressure in the crankcase 30 exceeds an amount that is sufficient to cause the diaphragm 52 to deflect from the first position to the tripped position, the pressure exerts a force on the second side 58, which causes the diaphragm 52 to move to the tripped position. The tripped position, in the embodiment shown in FIGS. 5-7 and 11, can also be described as a concave position of the diaphragm 52. The diaphragm 52 moves from its bulbous shape of FIGS. 2 and 10, into a shape that, in cross-section, resembles the letter "M" (FIGS. 6 and 11). Another way of viewing the movement of the diaphragm from the first position to the tripped position is by reviewing motion of an apex 74 of the diaphragm 52. The apex 74 is the region of the diaphragm that is located at approximate the center of the diaphragm spaced from the wall 62. i the first position, the apex 74 is projecting toward the engine crankcase 30. In the tripped position, the apex 74 is projecting outwardly toward the atmosphere and away from the engine crankcase 30. hi other words, the first position includes the apex 74 projecting outwardly away from the diaphragm surrounding wall 128. The tripped position includes the apex 74 being inverted and located within (circumscribed by) the diaphragm surrounding wall 128. h general, in preferred embodiments, the diaphragm 52 includes a visual indicator to indicate when the diaphragm 52 has moved from the first position to the tripped position. In other words, in preferred embodiments, the pressure indicator 50 will provide a visual signal to an observer to let him know that the diaphragm 52 has been tripped, h the specific embodiment illustrated, the visual indicator includes a tab 76 secured to the diaphragm 52. In preferred embodiments, the tab 76 is an integrally molded, one-piece structure with the diaphragm 52. The tab 76 is movable with the diaphragm 52 between the first position and the tripped position. Specifically, in the first position, FIGS. 3 and 4, the tab 76 follows the contour of the diaphragm 52. As can be seen, the tab 52 is located on the atmospheric side (the first side 56) of the diaphragm 52. As shown, the tab 76 lies even with the first side 56 and is against the first side 56. When the diaphragm 52 moves from the first position to the tripped position, the tab 76 is deflected in a position to be extending or projecting from the first side 56. Specifically, in the embodiment shown, the tab 76 has a free end 78. hi the first position, the free end 78 is against the first side 56 of the diaphragm 52. h the tripped position, the free end 78 is projecting or extending away from the first side 56. h the embodiment shown, in the tripped position, the tab 76 extends generally parallel to the direction of the wall 62 and of a central, longitudinal axis 80 of the pressure indicator 50. In preferred embodiments, when the tab 76 moves between the first position and the tripped position, there is a change in color that is visible to an observer. In the embodiment shown, this is achieved by having a patch 82 (FIG. 5) of color on the first side 56 in a region of the apex 74. This patch 82 is covered by the tab 76 when the diaphragm is in the first position. The patch 82 is exposed or uncovered when the tab 76 is moved to the tripped position. Because the patch 82 is exposed, it is visible by an observer from the atmospheric side. The pressure indicator 50 can also optionally include a patch 84 of a second, different color on the tab 76. The second patch 84 would be visible when the diaphragm is in the first position and not clearly visible when the tab 76 is in the tripped position. With patches 82 and 84, a color-coded signaling system can be developed. For example, the patch 82 on the first side 56 of the diaphragm 52 can be red, while the patch 84 on the tab 76 can be green. With such a signaling system, when the pressure indicator 50 is in the first, normal position (FIG. 3), the second patch 84 will be visible, in this case green. After the pressure has risen in the crankcase 30 sufficient to cause the diaphragm 52 to move to the tripped position (FIG. 5), the patch 82, in this case red, will become visible. The change from green to red will communicate to the observer that the blow-by filtration system 36 needs servicing. An example embodiment of a blow-by filtration system 36 is explained further below. After the blow-by filtration system 36 is serviced, the pressure indicator 50 can be conveniently and easily reset. Specifically, the diaphragm 52 is moveable from the tripped position to the first position in response to physical, manual contact by a pushing member on the first side 56 of the diaphragm 52. In the embodiment of FIGS. 2 - 8, the access opening 70 defines a size suitable to accommodate manually resetting the indicator 50. Specifically, the first side 56 of the diaphragm 52 can be manually accessed and have a force applied to move the diaphragm 52 from the tripped position back to the first position, i preferred embodiments, the access opening 70 is sized to accommodate a human finger such that the finger can penetrate the access opening 70, touch the first side 56 of the diaphragm 52, apply pressure to the diaphragm 52, and move the diaphragm 52 from the tripped position, FIGS. 5-7, to the first position, FIG. 3. In preferred embodiments, the access opening will be tubular, in some cases circular, with a diameter of at least 15 mm., typically at least 18 mm., and in many implementations 20-40 mm. As mentioned above, the diaphragm 52 is moveable from the tripped position to the first position in response to physical, manual contact by a pushing member on the first side 56 of the closed end 131 of the diaphragm 52. In the embodiment shown in FIGS. 2 - 8, the housing 60 defines a first end 132 at the access opening 70, and an opposite, second end 133. The housing second end 133 is obstruction-free and sized to permit passage of a finger to contact the first side 56 of the closed end 131 of the diaphragm 52 to move the diaphragm 52 from the tripped position to the first position. By the term "obstruction-free", it is meant that a human finger can access the diaphragm 52 and push the diaphragm 52 from the tripped position to the first position. That is, nothing is obstructing the convenient and free contact of a human finger onto the diaphragm in order to apply a pushing force, manually on the first side 56 to move the apex 74 from being inverted and located within the diaphragm surrounding wall 128 to a position where the apex 74 projects outwardly away from the diaphragm surrounding wall 128. Of course, a human finger need not be used. A tool or any type of pushing member could be used. In the embodiments of FIGS. 10 and 11, the pushing member includes a button 136 held by the porous cover 138. The cover 138 is over the housing second end 133 and can be made of a clear, transparent plastic defining holes for exposing the first side 56 of the diaphragm 52 to atmospheric pressure. The button 136 includes a knob 140 and an extension or pin 142 in extension from the knob 140. The extension 142 is moveable to contact the first side 56 of the closed end 131 of the diaphragm 52 to move the diaphragm 52 from the tripped position to the first position. As can be seen in FIGS. 10 and 11, the knob 140 is accessible from the atmospheric side, and can be depressed. By pressing the knob 140, it causes physical contact and a pushing force to be exerted on the first side 56 of the diaphragm 52 to move the diaphragm 52 to the first position. hi FIG. 9, there is a cross-sectional view of one useable blow-by filtration system 36. The particular blow-by filtration system 36 described is the type of system described in PCT WO 01/47618, published July 5, 2001 and PCT Pending Application US 03/36835 filed November 17, 2003, each of these documents being incorporated herein by reference. In the embodiment shown, the blow-by filtration system 36 includes a blow-by fluid inlet 90, a liquid outlet 92, and a filtered gas port 94. The filtered gas port 94 is in gas flow communication with the engine 30. Still in reference to FIG. 9, the blow-by filtration system 36 shown includes a two-stage element 96 that is removable and replaceable within a housing 98. The housing 98 includes a housing body 102 and a removable service cover 104 to provide access to the two-stage element 96. The two-stage element 96 has a first end cap 106 and a second end cap 108. The first end cap 106 circumscribes the blow-by fluid inlet 90. There is a first stage coalescer filter 110 that is oriented in extension across the blow-by fluid inlet 90. A tubular construction of media 112 forms a second stage filter 114 and extends between the first end cap 106 and second end cap 108. The tubular construction of media 112 defines an open tubular interior 116. The blow-by fluid inlet 90 is in flow communication with the open tubular interior 116. In the embodiment shown, the tubular construction of media 112 of the second stage filter 114, the first end cap 106, the second end cap 108, and the first stage coalescer filter 110 are unitary in construction. As used herein, the term "unitary" means that the first stage filter 110 and second stage filter 114 cannot be separated from each other without destroying a portion of the element 96. When the filter element 96 is handled, for example, during servicing, both the first stage filter 110 and second stage filter 114 are handled together. In the embodiment shown, the first stage coalescer filter includes a non-woven fibrous bundle 118 having a first upstream side 120. The upstream side 120 has a certain, defined surface area. The second stage filter 114 has an upstream side 122 that also defines an upstream surface area, hi the particular embodiment illustrated, there is a relationship between the upstream side surface area 120 and the upstream side surface area 122 between the first stage coalescer filter 110 and the second stage filter 114. In useable embodiments, the first upstream surface area will be not more than 25% of the upstream surface area of the second stage filter 114. hi many embodiments, this percentage will be not more than 10%, and in some cases, not more than 2%. In use, blow-by fluid 38 flows to the blow-by filtration system 36 by passing through the blow-by fluid inlet 90. From there, it flows through the coalescer filter 110. The coalescer filter 110 removes a portion of the liquid phase from the gaseous stream. The liquid that is coalesced within the coalescer filter 114 drains and exits the housing 98 through the liquid outlet 92. The gas phase is directed through an internal center tube 124, through a passage way 126, and through the upstream side 122 of the second stage filter 114. The second stage 114 removes at least a portion of particulates from the gas stream, and the cleaned gas stream is directed into the regulator valve 40 and out through the filtered gas port 94. A method of indicating pressure in an engine crankcase preferably uses structure as described herein. In general, pressure is sensed with a pressure indicator in a closed engine crankcase system. A diaphragm is moved in the pressure indicator from a first position to a tripped position when pressure in flow communication with the engine crankcase exceeds a predetermined amount. The pressure indicator is ultimately re-set by accessing the diaphragm in the pressure indicator from an atmospheric side of the pressure indicator and is manually moved from the tripped position to an untripped, normal, first position. Typically, the pressure indicator is reset after the blow-by filtration system is serviced. By servicing, typically, the two-stage element 96 is removed from the housing 98 and replaced with a new two-stage element. In one method, the step of resetting the pressure indicator includes inserting a pushing member, such as a finger from the atmospheric side of the pressure indicator into an access opening in the pressure indicating and pushing the diaphragm from the tripped position to the first position. In the embodiments of FIGS. 10 and 11, the step of resetting the pressure indictor includes pushing a button on the pressure indicator to cause physical contact between a portion of the button and the atmospheric side of the closed end of the diaphragm to move the diaphragm from the tripped position to the first position.

Claims

What is claimed is:

1. A pressure indicator comprising: (a) a housing; (b) a diaphragm held by the housing; (i) the diaphragm having a diaphragm surrounding wall defining an interior, an open end, and a closed end; (A) the closed end having a first side, an opposite second side, and a center apex; (1) the first side being in communication with the interior of the diaphragm surrounding wall; (ii) the diaphragm being deflectable between a first position and a tripped position and between the tripped position and first position; (A) the first position including the apex projecting outwardly away from the diaphragm surrounding wall; (B) the tripped position including the apex being inverted and located within the diaphragm surrounding wall; (iii) the diaphragm being movable from the tripped position to the first position in response to physical, manual contact by a pushing member on the first side of the closed end of the diaphragm.

2. A pressure indicator according to claim 1 wherein: (a) the housing has first and second open ends; the housing second end being obstruction-free and sized to permit passage of a pushing member to contact the first side of the closed end of the diaphragm to move the diaphragm from the tripped position to the first position.

3. A pressure indicator according to claim 1 wherein: (a) the housing has first and second open ends and includes a cover at the second open end; (i) the pushing member being a button held by the cover; the button including an extension movable to contact the first side of the closed end of the diaphragm to move the diaphragm from the tripped position to the first position.

4. A pressure indicator according to any one of claims 1-3 wherein: (a) the diaphragm has a thickness less than 0.8 mm.

5. A pressure indicator according to any one of claims 1-4 wherein: (a) the diaphragm comprises reaction injection molded silicone.

6. A pressure indicator according to any one of claims 1-5 wherein: (a) the diaphragm includes a visual indicator to indicate when the diaphragm has moved between the first position and tripped position.

7. A pressure indicator according to claim 6 wherein: (a) the visual indicator includes a tab moveable with the diaphragm between the first position and the tripped position; (i) when the tab moves between the first position and the tripped position, a change in color on the indicator is visible.

8. A closed engine crankcase system comprising: (a) an air filter; (b) an engine in gas flow communication with the air filter; the engine having a crankcase producing blow-by fluids; (c) a blow-by filtration system downstream of and in fluid communication with the engine crankcase; (i) the blow-by filtration system having a blow-by fluid inlet, a liquid outlet, and a filtered gas port; (ii) the filtered gas port being in gas- flow communication with the engine; and (d) a pressure indicator in gas flow communication with the engine crankcase and upstream of the blow-by filtration system; (i) the pressure indicator including a housing and a diaphragm held by the housing; and (ii) the diaphragm being movable from a first position to a tripped position in response to pressure downstream of the engine crankcase.

9. A closed engine crankcase system according to claim 8 wherein: (a) the diaphragm has an atmospheric side exposed to atmospheric pressure and crankcase pressure side exposed to crankcase pressure; (i) the diaphragm being movable from the tripped position to the first position by manually pushing on the atmospheric side of the diaphragm.

10. A closed engine crankcase system according to claim 9 wherein: (a) the diaphragm has a diaphragm surrounding wall defining an interior, an open end, and a closed end; (i) the closed end defining the atmospheric side, an opposite side being the crankcase pressure side, and a center apex; (A) the atmospheric side being in communication with the interior of the diaphragm surrounding wall; (ii) the first position including the apex projecting outwardly away from the diaphragm surrounding wall; and (iii) the tripped position including the apex being inverted and located within the diaphragm surrounding wall.

11. A closed engine crankcase system according to claim 10 wherein: (a) the housing has first and second open ends; the housing second end being obstruction-free and sized to permit passage of a finger to contact the atmospheric side of the closed end of the diaphragm to move the diaphragm from the tripped position to the first position.

12. A closed engine crankcase system according to claim 10 wherein: (a) the housing has first and second open ends and includes a cover at the second open end; (b) the pressure indicator further includes a button held by the cover; the button including an extension movable to contact the atmospheric side of the closed end of the diaphragm to move the diaphragm from the tripped position to the first position.

13. A closed engine crankcase system according to any one of claims 8-12 wherein: (a) the pressure indicator is constructed and arranged to move the diaphragm from the first position to the tripped position responsive to a pressure of at least 8 inches of water.

14. A closed engine crankcase system according to any one of claims 8-13 wherein: (a) the pressure indicator includes a visual signal to indicate when the diaphragm has moved from the first position to the tripped position.

15. A closed engine crankcase system according to any one of claims 8-14 wherein: (a) the blow-by filtration system includes a first stage coalescer filter and a second stage gas filter; and (b) the pressure indicator being upstream of the first stage coalescer filter.

16. A closed engine crankcase system according to claim 15 wherein: (a) the first stage coalescer filter is oriented in extension across the blow- by fluid inlet and separating liquid from a gas stream; (b) the liquid outlet being is in liquid flow communication with the first stage coalescer filter; and (c) the second stage gas filter is in gas flow communication with and downstream of the first stage coalescer filter; (i) said filtered gas port being downstream of said second stage filter.

17. A method of indicating pressure in an engine crankcase; the method comprising: (a) sensing pressure with a pressure indicator in a closed engine crankcase system; the closed engine crankcase system including an air filter; an engine in gas flow communication with the air filter; the engine having a crankcase producing blow-by fluids; a blow-by filtration system downstream of and in fluid communication with the engine crankcase; the blow-by filtration system having a blow-by fluid inlet, a liquid outlet, and a filtered gas port; the filtered gas port being in gas-flow communication with the engine; (b) moving a diaphragm in the pressure indicator from a first position to a tripped position when pressure in flow communication with the engine crankcase exceeds a predetermined amount; and (c) re-setting the pressure indicator by accessing the diaphragm from an atmospheric side of the pressure indicator and manually pushing the diaphragm from the tripped position to the first position.

18. A method according to claim 17 wherein: (a) the diaphragm has a diaphragm surrounding wall defining an interior, an open end, and a closed end; (i) the closed end defining an atmospheric side, an opposite side being a crankcase pressure side, and a center apex; (A) the atmospheric side being in communication with the interior of the diaphragm surrounding wall; (ii) the first position including the apex projecting outwardly away from the diaphragm surrounding wall; (iii) the tripped position including the apex being inverted and located within the diaphragm surrounding wall; and (b) the step of moving a diaphragm in the pressure indicator from a first position to a tripped position includes pressure from the engine crankcase moving the diaphragm from the first position into the tripped position.

19. A method according to claim 18 wherein: (a) the step of re-setting the pressure indicator includes inserting a finger from the atmospheric side of the pressure indicator into an access opening in the pressure indicator and pushing the diaphragm from the tripped position to the first position.

20. A method according to claim 18 wherein: (a) the step of re-setting the pressure indicator includes pushing a button on the pressure indicator to cause physical contact between a portion of the button and the atmospheric side of the closed end of the diaphragm to move the diaphragm from the tripped position to the first position.