Patent Application
20070251512
The present disclosure relates to control of crankcase emissions from an internal combustion engine and, more particularly, to a “breather” assembly that allows for venting of accumulated blow-by gases in the crankcase while separating crankcase oil from blow-by gases.
In internal combustion engines, fuel and air may be introduced into cylinders for combustion. Pistons may move within the cylinders under the influence of a crankshaft located in a crankcase. In each cylinder, a piston may compress the fuel and air mixture prior to combustion of the mixture. Combustion may then drive the pistons and yield power output. The power output may be used to drive a machine.
Combustion in the cylinder may release energy and generate combustion products and by-products, most of which may be exhausted from the cylinder into an exhaust system of the engine during the exhaust phase of the combustion cycle. However, some of the combustion products may enter into the crankcase by blowing past seal rings around the pistons, and are thus termed “blow-by gases” or simply “blow-by.” Blow-by gases contain contaminants normally found in exhaust gases, such as, for example, hydrocarbons (HC), carbon monoxide (CO), nitric oxides (NOx), soot, and unburned or partially burned fuel. In addition, because the crankcase is partially filled with lubricating oil being agitated at high temperatures, the blow-by gases may also contain oil droplets and oil vapor. Lubricating oil in the crankcase tends to be atomized or otherwise entrained in the hot blow-by gases to form what may be termed an aerosol.
It may be desirable to vent blow-by gases in the crankcase (including, for example, entrained lubricating oil) as crankcase emissions to relieve pressure in the crankcase. Some systems vent the crankcase emissions to the air intake side of the engine for mixing with the air and fuel introduced into the cylinders. Those systems where the crankcase emissions are reintroduced into the engine for burning belong to the class of closed crankcase ventilation (CCV) systems.
Some engines, such as large diesel engines, for example, utilize forced induction to enhance the power output of the engine. This may involve the use of superchargers or turbochargers in an engine design assembly. Returning crankcase emissions to the air intake side of engine, such as via a compressor in a supercharger or turbocharger, can result in fouling of the components (e.g., the compressor wheel) in a relatively short time period. One effect of reintroducing blow-by gases into an intake air of an engine may include producing contaminant buildup (e.g., oil coatings and sludge), within engine components including, for example, turbochargers and cooling devices such as air-to-air aftercoolers (ATAAC). Contaminants, such as those left by blow-by gases, within engine sub-components can negatively affect, for example, power production of the engine and possibly reduce the operational life thereof. The fouling may be further compounded in systems which, for example, utilize multiple turbocharger systems, as the heat increases in downstream compressor units. Again, other components, such as cooling units downstream of a supercharger or turbocharger, may be fouled. Even with the development of technologies to address purifying crankcase emissions before being returned to the intake system, some level of contamination may still exist that may be harmful to engine components, such as a supercharger or turbocharger, cooling units, or various other engine intake system components.
U.S. Pat. No. 6,941,914 issued to Snyder et al. (“Snyder”) discloses an internal combustion engine having a CCV system including a breather assembly for venting blow-by gases from a crankcase. A breather conduit is connected to a hose fitting of the breather assembly to convey blow-by gases to the air filter cavity of the engine for recycling. However, the CCV system design of Snyder et al. may not address contamination issues that can result from recycling crankcase emissions through various engine components. Furthermore, it may be necessary to provide additional equipment, such as additional ventilation devices, in order to filter returned crankcase emissions. This can add to the manufacturing costs of the overall CCV system design. Use of additional equipment may also require additional servicing such as through periodic maintenance or replacement if the equipment becomes defective. Hence, additional servicing or maintenance costs may be associated with providing such additional equipment.
The present disclosure is directed towards overcoming one or more of the problems set forth above.
In one aspect, the present disclosure may be directed to a breather assembly. The breather assembly may include a housing having an inlet for receiving crankcase emissions and an outlet for discharging the emissions, wherein the outlet is configured for direction connection to an exhaust system. The breather assembly may further include a check valve configured within an interior of the housing and a treatment element configured to treat emissions received from the crankcase.
In another aspect, the present disclosure may be directed to a method of venting emissions from a crankcase. The method may include providing a breather assembly having a check valve and an exhaust system, The method may further include coupling the breather assembly between the crankcase and the exhaust system and venting emissions from the crankcase, through the breather assembly, and directly to the exhaust system in a first flow direction.
In yet another aspect, the present disclosure may be directed to an engine assembly. The engine assembly may include a crankcase, a housing having an inlet for receiving crankcase emissions, and an outlet for discharging the emissions. The engine assembly may further include an exhaust system in direct connection with the outlet. The engine assembly may further include a check valve configured within an interior of the housing.
Referring to
Turbocharger 26 may include a compressor 36, powered by a turbine 38 driven by engine exhaust flow 34. The compressor 36 may pressurize intake air 28 to allow a greater mass of fuel/air mixture in the engine cylinders of engine 14. The result may be an increase in power and improved engine efficiency. However, as a byproduct of pressurization, the temperature of intake air 28 may also increase, which may be undesirable. As noted above, heated charged air 30 may be cooled prior to entering air intake manifold 56 by passing through ATAAC 32.
In one exemplary disclosed embodiment, heated charged air 30 from compressor 36 of turbocharger 26 may be admitted into ATAAC 32 through an inlet port 40. After traversing ATAAC 32 and having undergone a heat exchange operation with respect to relatively cool ambient air simultaneously passing over and around ATAAC 32, the previously heated charged air 30 may be exhausted through an outlet port 42 of ATAAC 32 as relatively cooled charged air 44, which may then be routed to engine air intake manifold 56. As shown in
During operation, blow-by gases may build up in a crankcase 16 of the engine 14. A breather assembly 46, may be provided and coupled, for example, to crankcase 16 for venting blow-by gases 48 from the engine crankcase.
Thus, the disclosed embodiment shown in
Breather assembly 46 may include a filter media 60 which may include porous or mesh material. Filter media 60 may facilitate trapping of oil within an interior region of breather assembly 46 as blow-by gases 48 pass therethrough and towards exhaust system 50.
In order to prevent reverse flow of exhaust or blow-by gases 48 back into crankcase 16, a check valve 58 may be provided within breather assembly 46. In one embodiment, check valve 58 may include a reed or flapper type valve including, for example, flexible material such as spring steel. Check valve 58 may be orientated to allow blow-by gases 48 to escape from breather assembly 46, while preventing a reverse flow of blow-by gases 48 from entering crankcase 16 of engine 14 through the breather assembly 46.
Turning to
Turning to
Gasket 70 is shown in alignment with mid support section 92, and, in the disclosed embodiment, is disposed between mid support section 92 and top support section 90 in a final assembly. Mid support section 92 may include installed components of a reed valve assembly 86 in accordance with an exemplary embodiment of the disclosure. Respective components of reed valve assembly 86 are shown more easily in
Reed valve element 110 may be provided and orientated to allow blow-by gases 48 to escape from breather assembly 46, while preventing a reverse flow of blow-by gases 48 from entering crankcase 16 of engine 14 through the breather assembly 46. Valve seat 108, made of a rigid material, may assist in prolonging the lifespan of reed valve element 110 such as by preventing excessive wear. Additionally, valve seat 108 may enhance a flat mating surface of reed valve element 110 in a final assembly. Furthermore, valve seat 108 (in combination with recessed portion 114 of mid support section 92) may facilitate preventing reed valve element 110 from flexing in an open configuration should blow-by gases 48 attempt to re-enter breather assembly 46 (such as in a reverse flow direction through output port 68) as discussed below. Valve seat opening 102, such as one corresponding to opening 104 of mid support section 92, may also be included in valve seat 108. In similar fashion, valve seat opening 102 may accommodate vented blow-by gases 48 received through inlet ports 66 (
Reed valve element 110 may be seated upon valve seat 108. Reed valve element 110 may include spring steel material. Alternatively, reed valve element 110 may include other materials suitable for venting blow-by gases such as including synthetic resin material. In one disclosed embodiment, reed valve element 110 (such as one including spring steel material) may have a thickness of approximately 0.305 mm ( 12/1000 inch). Other suitable thicknesses of reed valve element 110 may be utilized which may not only prevent reverse flow but also remain pliable for responding to appropriate crankcase pressure to vent blow-by gases 48. Reed valve element 110 may include opening 122 for receiving retaining member 116 (
Valve stop 112, made of a rigid material such as steel, may be seated upon reed valve element 110. A configuration of valve stop 112 may include a slightly curved configuration. An opening 124 may be provided within valve stop 112 for receiving retaining member 116 (
Turning again to
As further shown in
The disclosed breather assembly 46 may have applicability in any system requiring the venting of a emissions. In addition, breather assembly 46 may have applicability in any system requiring protection from vented gas. For example, the disclosed breather assembly 46 may be used in connection with internal combustion engines. In particular, and as shown in
Having achieved a final assembly in connection with an engine 14 and directly coupled to exhaust system 50, breather assembly 46, of the disclosed embodiment, may be configured to receive blow-by gases 48, filter the received gases, and emit the filtered gases directly to exhaust system 50. An effect of routing crankcase emissions directly to exhaust system 50, as described herein, may produce an increased pressure within crankcase 16 of engine 14. Hence, the crankcase pressure obtained by the disclosed embodiment may achieve pressures greater than CCV systems which route blow-by gases to the intake system of the engine. In one example, the crankcase pressure achieved by the disclosed embodiment may be on an order of 5 psi or greater. Whereas, comparatively, some traditional CCV systems (e.g., those routing blow-by gases 48 to the intake system) may produce a crankcase pressure generating only a fraction of 1 psi. Thus, the arrangement of the disclosed embodiment is conducive to creating a flow direction of blow-by gases in order to expel the gases from crankcase 16, into and through breather assembly 46, and towards exhaust system 50. Reducing exposure of high temperature blow-by gases to engine components, such as through venting, may be beneficial for protecting the components against gases which may achieve elevated temperatures. The aforementioned flow direction may also be desirable to prevent high temperature exhaust gases from coming into contact with engine components and possibly creating damage thereto.
In general, the aforementioned flow direction may exist so long as greater pressure is produced and maintained within crankcase 16 than within the exhaust system 50. If the pressure within crankcase 16 is less than the pressure in exhaust system 50, engine exhaust gases will travel towards the lower pressure within crankcase 16 in a reverse flow direction. Reverse flow of exhaust gases back into engine 14 may not be desirable for several reasons. One reason may include risk of damage caused by thermal effects of exhaust gases returning into contact with engine components. Since exhaust gases can reach relatively high temperatures (e.g., 500° C. or greater), it may be possible to cause damage, for example, to engine components should the aforementioned gases make contact in a reverse flow direction. In one example, exhaust gases may melt engine components, such as valve covers of engine 14. Additionally, engine components that come into contact with exhaust gases may be susceptible to corrosive effects. This, in turn, could reduce the operational life of those components.
Check valve 58, configured within breather assembly 46, prevents reverse flow of exhaust gases back into crankcase 16. Hence, check valve 58 may be orientated to allow blow-by gases 48 to escape from breather assembly 46 while preventing a reverse flow of engine exhaust gases 48 from entering a crankcase of engine 14 when the pressure in the exhaust system 50 is greater than crankcase 16.
In operation, blow-by gases 48, in one exemplary embodiment, may pass around pistons from combustion chambers into crankcase 16 during operation of engine 14. The blow-by gases 48 may tend to accumulate within crankcase 16 and increase the pressure therein. When appropriate pressurization of crankcase 16 occurs (such as when the pressure within crankcase 16 overcomes the pressure of exhaust system 50), blow-by gases 48 may be vented by entering into inlet ports 66 of breather assembly 46. Blow-by gases 48 may accumulate within an inner chamber 118 and be filtered through filter media 60. Within inner chamber 118, oil may separate from blow-by gases 48 by gravity and condensation and drip back into the crankcase. In addition, oil may be trapped within filter media 60. Blow-by gases 48 may then pass through opening 104 and valve seat opening 102, past reed valve element 110, and vented through outlet port 68.
Discharge of blow-by gases 48 in the described manner may cause reed valve element 110 to deflect away from valve seat opening 102 and towards valve stop 112. This action may facilitate venting of blow-by gases 48 from crankcase 16. Conduit 62 may couple outlet port 68 of breather assembly 46 to exhaust system 50 in order to convey blow-by gases 48 to the exhaust for treatment and/or release into the environment.
When a pressurization of the crankcase is not sufficient to overcome pressurization of exhaust system 50, reed valve element 110 may serve to protect against emitting engine exhaust gases 48 back into crankcase 16 through breather assembly 46. Engine exhaust gases in reverse flow may exert a force upon reed valve element 110 such that reed valve element 110 is deflected toward valve seat 108. The biasing force produced by the exhaust gases may facilitate deflecting reed valve element 110 to cover valve seat opening 102. This action will cause passage of exhaust gases through valve seat opening 102 to become blocked. The relatively flat configuration of valve seat 108, provided by the disclosed embodiment, may further assist in providing better coverage/sealing of valve seat opening 102 by reed valve element 110 to prevent exhaust gases from entering inner chamber 118. With the reverse flow of exhaust gases cut off by reed valve element 110, exhaust gases may be prevented from re-entering crankcase 16. Thus, the disclosed embodiment may ensure protection against exhaust gases re-entering and passing through breather assembly 46 and coming into contact with components of engine 14. As previously mentioned, such contact may result in damage to engine components exposed, for example, to increased heated temperatures of returning engine exhaust gases. Utilizing disclosed breather assembly 46 in combination with check valve 58, may also prevent, or greatly reduce, corrosive effects of engine components generated, in some instances, by contact with returned exhaust gases. Hence, the disclosed embodiment may facilitate increased operational life of engine components.
It will be apparent to those skilled in the art that various modifications and variations can be made in the disclosed breather assembly and methods without departing from the scope of the disclosure. Additionally, other embodiments of the breather assembly and methods will be apparent to those skill in the art from consideration of the specification. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.
