This invention relates to internal combustion engines, including but not limited to recirculation of crankcase gases into the intake system of an engine.
The present invention relates to a closed breather system for a crankcase of an internal combustion engine of the type which recirculates piston blow-by gases in the crankcase to the intake air line of an engine and, more particularly, to a breather system capable of forming an open loop breather system under high loads, and a closed loop breather system under light loads.
Ideally, the pressure within an internal combustion engine crankcase should be maintained at a level equal to or slightly less than atmospheric pressure to prevent external oil leakage through the various gasketed joints, such as that between the valve cover and the cylinder head. Combustion gases are generated during the operation of an internal combustion engine. A small amount of these gases leaks past the piston seals of the internal combustion engine, and unless the gases are removed from the crankcase, they become trapped. These gases, commonly referred to in the art as “blow-by” gases, need to be released. Because of the “blow-by” gases, the crankcase pressure will inherently rise, promoting leakage of oil from the crankcase. Originally, crankcase pressure was vented to the atmosphere through a breather to solve this problem.
Environmental considerations dictate that the blow-by gases in the crankcase be vented back to the combustion chamber rather than being released to the atmosphere. Accordingly, the crankcase was scavenged by being connected to the engine air intake thereby resulting in a vacuum in the crankcase with a depression valve being used to prevent the negative pressure in the engine cavity from exceeding a predetermined amount.
Government regulations require the engine to be within defined levels of exhaust emissions, including crankcase vapors, under specific environmental conditions which include ambient temperature and altitude. Outside of the specified environmental conditions, the “emissions window” the engine is allowed to have different emission levels.
The present inventor has recognized that highly turbocharged engines with closed breather systems suffer from ongoing turbocharger compressor “coking”—a varnish like residue that results when oil and fuel molecules in blow-by gasses come in contact with hot turbocharger compressor surfaces and oxidizes, which builds up over time and eventually affects turbocharger efficiency. Thus, it is desirable to have breather systems capable of alternating between operation as a closed breather system and as an open breather system to lessen the impact of coking resulting from operation under only a closed breather system.
Current breather bypass valves that attempt to allow for alternation between a closed breather system and an open breather system can be cumbersome, expensive, and require a boost supply for actuation.
The present inventor has recognized the need for a simple, easily packageable, self-contained valve that does not require an external boost supply, which opens the breather at higher load and higher speeds, while maintaining a closed breather system at lower loads and lower speeds.
The present inventor has recognized the need for an engine that helps meet EPA emission standards and prevent DOC/DPF Poisoning, while preventing degradation of turbocharger performance over time.
The exemplary embodiment of the invention provides a valve for a breather system that allows a breather system to alternate between a closed and open breather system according to the load and speed of the vehicle.
The exemplary system would function as a closed breather system at low speeds and low load conditions, and as an open system at high speeds and high loads. The exemplary system provides a dual function selection valve that responds to air intake pressure conditions.
An exemplary embodiment of the invention provides a dual function selection valve attached between a breather and turbocharger compressor air intake. The valve, responsive to air intake depression, is located within the blow-by gas flow path, downstream of the oil mist separator, and allows the blow-by gas to flow alternatively between a flow path conduit to the compressor air intake, and a second flow path between the engine compartment and atmosphere.
The system can comprise a three-way valve with a check valve and a one-way flow valve. The check valve and the one-way flow valve operate in conjunction with one another to allow the breather system to operate as a closed breather system under low speeds and low loads, and as an open breather system under high speed and high loads.
An exemplary method of the invention for operating an internal combustion engine includes the steps of:
providing a dual function selection valve located between a breather tube and a turbo air intake, the dual function selection valve comprising a check valve and a one way flow valve;
providing an outlet to atmosphere for the blow-by gas when the breather system operates as an open breather system;
providing an outlet to the turbo air intake when the breather system operates as a closed breather system;
operating as an open breather system when a depression in the turbo inlet is greater than a predetermined value; and
operating as a closed breather system when a depression in the turbo inlet is less than the predetermined value.
The steps of operating as an open or closed breather system can be managed by a check valve which opens and closes a conduit according to the level of turbo air intake depression.
Numerous other advantages and features of the present invention will be become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings.
While this invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated.
Referring now to the drawings in greater detail, there is illustrated therein a dual function breather bypass system of the present invention generally identified by the reference numeral 10 mounted on an internal combustion engine 18, preferably a diesel engine (
The breather system 10 comprises a breather tube assembly 12 having an inlet end 14 in fluid communication with the interior of a valve housing 16 of engine 18 and an outlet end 20 (
In a V-8 engine, such as shown in
The tube fitting 13 includes an opening 40. A complete description on arrangement and structure of the tube fitting 13 can be found in U.S. Pat. No. 5,140,968, herein incorporated by reference.
The breather tube assembly 12 includes an oil mist separator 44 connected to a dual function selection valve 46 (
The oil mist separator 44 can be configured as described in U.S. Pat. No. 7,185,643, herein incorporated by reference.
The dual function selection valve 46 can be a three-way valve, such as a T-valve, comprising a check valve 100 and a one-way flow valve 90 as illustrated in
The check valve opens and closes according to the pressure depression of the air intake line 22, and correspondingly the depression in the downstream breather tube 50, which are reflective of turbocharger conditions under high or low load operating conditions. Operation of the engine under high loads generates a stronger vacuum, thus resulting in greater air intake line 22 pressure depression than operation of the engine under lighter loads.
The check valve 100 automatically closes when the difference in pressure between the air intake line 22 and the blow-by pressure within breather tube 51 exceeds a preset differential pressure, for example, 5″ H2O. Thus, when the turbocharger is spinning sufficiently to reduce the pressure (below atmospheric pressure) on the right side of the valve 100 to 5 inches of H2O less than the pressure on the left side of the valve 100, the valve closes. When the check valve closes as illustrated in
When the air intake line 22 depression is less than the preset differential pressure, the check valve is held open by its spring, as illustrated in
From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US2010/040630 | 6/30/2010 | WO | 00 | 3/15/2013 |