Gas separation – Combined or convertible – In motor vehicle
Reexamination Certificate
1999-09-28
2001-07-17
Simmons, David A. (Department: 1724)
Gas separation
Combined or convertible
In motor vehicle
C055S414000, C055S502000, C055S503000, C055SDIG001, C123S573000
Reexamination Certificate
active
06261333
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an air filter for internal combustion engines having a primary air region and a secondary air region disposed within a housing. The primary air comes from air located outside the internal combustion engine while the secondary air comes from crankcase emissions flowing from a crankcase in the internal combustion engine to the air filter.
2. Description of the Prior Art
Various filters for reducing crankcase emissions are known an the art. For example, U.S. Pat. No. 5,125,940 to Stanhope, et al. discloses a venturi element 40 disposed outside of the downstream end of the housing 16 of the in-line air filter apparatus 10. Ambient air travels through tubular air filter 34, outside-in, and to the air intake hose 12 via the concave venturi element.
U.S. Pat. No. 5,562,746 to Raether discloses an air filter assembly 10 having a plurality of filters 32 mounted to side walls 17 via tube sheet structure 28. A concave venturi 70 is fixedly coupled to each filter 32 by means of the tube sheet structure 28 and the venturi flanges 88.
U.S. Pat. No. 4,272,263 to Hancock discloses a gas cleaning arrangement having a venturi sheet 4 disposed within a bag housing 1. Venturi sheet 4 supports a plurality of tubular filter arrangements 7 where each filter 7 includes a convex venturi 24, and accordingly the venturi is contained within housing 1.
U.S. Pat. No. 5,383,356 to Zurek et al. discloses a concave venturi 76 that is separately connected to the outside of the downstream end of housing 86 or may be integrated with the housing as a single unitary element.
U.S. Pat. Nos. 4,713,097 to Grawi et al 5,106,397 to Jaroszcyk, et al. and 5,120,334 to Cooper each disclose an air filter having a venturi, integrated with a housing, where the venturi is not adjacent to an air filter element.
U.S. Pat. Nos. 4,272,262 to Britt et al. 4,834,784 to Biganset, and 5,196,653 to Kiss disclose air filters with venturi elements.
The present invention is an improvement over the prior art, because none of the prior art shows an air filter device having a venturi element shaped to be contained completely within the body of the housing and positioned such that crankcase emissions flow from a secondary air region past the primary air region and out of the housing. In addition, the prior art does not disclose the venturi element described above that is fixedly attached to the downstream end of an air filter element.
SUMMARY OF THE INVENTION
The invention relates to an air filter comprising a filter housing and a filter element disposed within the housing. The filter is disposed on an engine air intake of an internal combustion engine. Inside the filter housing is a primary air region and a secondary air region. The primary air region is separated from the secondary air region via a barrier which is connected to a venturi element within the housing. A filter element is disposed within the primary air region to filter primary air flow and is shielded from the secondary air in the secondary air region via the barrier. In a first embodiment of the invention, the barrier is attached to the housing. In a second embodiment of the invention the barrier is attached to the filter. In a third embodiment of the invention, the barrier is not attached to either the filter element or the housing, rather it can be inserted into the housing before the filter is inserted into the housing.
This primary air region receives primary air from a source outside of the internal combustion engine. The secondary air region, also known as a crankcase ventilation chamber, is disposed within the housing and is designed to receive emissions from a crankcase while keeping these emissions separate from the primary air region. These crankcase emissions pass through the filter housing and then on to the internal combustion engine so that they undergo further combustion within the engine.
In an internal combustion engine, crankcase emissions are a result of gas escaping past a set of piston rings and into an engine crankcase due to high pressures in an engine's cylinder during compression and combustion. These escaped gases known as blowby gas, pass through the crankcase where they become contaminated with oil mist.
In an open crankcase ventilation system, the contaminated blowby is vented out of the crankcase, through the engine breather to the atmosphere. A closed crankcase ventilation system is one which by definition does not allow crankcase emissions (CCE) to be released into the atmosphere. This is typically accomplished by directing or recirculating the blowby gas back into the combustion process via the engine air intake. This is often referred to as an ingestive system. With the present invention, the air filter is designed for a closed crankcase ventilation system because it is designed to receive crankcase emissions into the crankcase ventilation chamber in the filter.
The goal of a closed crankcase ventilation system is to prevent the release of crankcase emissions to the atmosphere. This must be done in a way that does not affect engine performance and reliability. If oil mist in the CCE contaminates the critical engine components, such as turbo compressors, after coolers and valves, engine performance and reliability degrades over time and costly maintenance is incurred. Therefore, oil mist must be removed from CCE prior to introduction to the engine air intake. A filter or separator is typically used for this purpose. However, the filter or separator represents a resistance to air flow, which has the undesirable effect of increased engine crankcase pressure. In addition, the more effective this crankcase filter, the greater its change in pressure and crankcase pressure. To mitigate this unwanted effect, a source of enhanced vacuum is needed. A properly designed venturi in the combustion air flow filter can provide the required vacuum to overcome the crankcase filter drop in pressure and reduce the crankcase pressure.
To keep the crankcase from bleeding or weeping this filter must be designed to enhance the pressure drop or vacuum in the system to draw the secondary air flow out of the secondary air chamber.
For example, in one type internal combustion engine, primary air flows through a filter silencer to a compressor. The compressor is driven by a turbine. The turbine is driven by the exhaust gases emitted from the internal combustion engine.
Once the gases are compressed by the compressor, they flow into an after cooler which cools these compressed gases. Next, these gasses flow into an internal combustion engine where they aid in the combustion of the fuel allowing the internal combustion engine to operate. The exhaust gases are driven out of the internal combustion engine, through the turbine and out into the atmosphere. However, crankcase emissions flow to a crankcase filter for further filtration. This crankcase filter is designed to filter out oil while sending the additional gasses back into the secondary air region of the filter housing and onto the internal combustion engine for further combustion.
One object of the invention is to provide an air filter for receiving primary air for combustion from the crankcase.
Another object of the invention is to provide a connection for receiving crankcase emissions.
Another object of the invention is to place the secondary air region in the air filter in a space saving manner.
Another object is to provide enhanced vacuum at the crankcase emission connection.
Another object of the invention is for the secondary air region to act as a crankcase ventilation chamber designed to ventilate exhaust from an internal combustion engine's crankcase, thereby reducing crankcase pressure and engine weeping.
Another object of the invention is to have a crankcase ventilation chamber with a negative pressure to draw crankcase emissions out of the crankcase.
Still another object of the invention is to provide a venturi enclosed within a housing, downstream of the secondary air region to increase the negative pressure within
Collard & Roe P.C.
Diesel Research Inc.
Hopkins Robert A.
Simmons David A.
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