Patent Application
20080127953
The invention relates to an engine head cover for an internal combustion engine. More particularly, the invention relates to an engine head cover having an integrated oil separator for separating oil from crankcase gases during operation of the engine.
An internal combustion engine typically includes a combustion chamber, where a fuel air mixture is burned to cause movement of a set of reciprocating pistons, and a crankcase, which contains the crankshaft driven by the pistons. During operation, it is normal for the engine to experience “blow-by,” wherein combustion gases leak past the piston-cylinder gap from the combustion chamber and into the crankcase. These blow-by or crankcase gases contain moisture, acids and other undesired by-products of the combustion process.
An engine typically includes a Positive Crankcase Ventilation (PCV) system for removing harmful gases from the engine and prevents those gases from being expelled into the atmosphere. The PCV system does this by using manifold vacuum to draw vapors from the crankcase into the intake manifold. Vapor is then carried with the fuel/air mixture into an intake manifold of the combustion chambers where it is burned. Generally, the flow or circulation within the system is controlled by the PCV valve, which acts as both a crankcase ventilation system and as a pollution control device.
It is normal for crankcase gases to also include a very fine oil mist. The oil mist is carried by the PCV system to the manifold. The oil mist is then burned in the combustion chamber along with the fuel/air mixture. This results in an increase in oil consumption. A known method of removing oil from the crankcase gases is to use an oil separator. The crankcase gases flow through the oil separator. Localized high pressure areas in the oil separator promote separation of oil from the gases. The oil is re-introduced back to a sump via a drain device. The sump generally holds excess oil in the system.
It remains desirable to provide an improved oil separator that is more efficient than conventional oil separator designs in the removal of oil from crankcase gases. It also remains desirable to provide an oil separator that is compact in size and integral with a part of the engine housing, such as a head cover, in order to reduce the packaging space occupied by the oil separator inside of the engine.
According to one aspect of the invention, a head cover assembly is provided for covering a crankcase of an internal combustion engine. The head cover assembly includes a head cover and an oil separator. The head cover has opposite outer and inner surfaces. The oil separator separates oil from crankcase gases passing therethrough. The oil separator has a housing disposed along an inner surface of the head cover. The housing has at least one side wall integral with the head cover, which together with the head cover define an interior space of the oil separator.
Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Referring to
A portion of the head cover 12 extends between the side walls 22, 24, 26, 28 to form an interior space. A plate 40 cooperates with the side walls 22, 24, 26, 28 to enclose the interior space of the oil separator 20. The head cover 12 has at least one threaded bore 29 for securing the plate 40 to the side walls 22, 24, 26, 28 using a bolt. A gasket (not shown) may be disposed between the side walls 22, 24, 26, 28 and the plate 40 to prevent gases from leaking from the interior space of the housing 30. Alternatively, the housing may have a generally cylindrical side wall that extends from the inner surface of the head cover instead of the straight side walls of the illustrated embodiment. The plate would then have a generally circular shape to cooperate with the generally cylindrical shape of the side wall.
The housing 30 of the oil separator 20 includes an inlet and an outlet. A plurality of guide walls 43 extend from the head cover 12 toward the plate 40 to define a path 39 that directs crankcase gases through the housing 30. The path 39 is shaped to promote separation of oil from crankcase gases as the gases flow through the path 39 between the inlet and outlet. The separated oil is collected in the housing 30 and re-introduced to the oil sump (not shown) for re-use in the engine.
A second embodiment of the head cover assembly 110 is shown in
During assembly, the cap 41 is inserted into the recess formed by the cylindrical side wall 50. The cap 41 is then turned about its longitudinal axis to cause threading engagement between the threads 42 on the cap 41 and mating threads 44 formed in the cylindrical side wall 50, thereby securing the cap 41 to the head cover 112. The cap 41 is fully inserted when it contacts a locating surface 52 formed head cover 112 adjacent a bottom end of the cylindrical side wall 50. The cover plate 45 is disposed between the cap 41 and the head cover 112. The plurality of guide walls 143 extend from the cover plate 45 to define the flow path for crankcase gases passing through the oil separator 120.
A third embodiment of the head cover assembly 210 are shown in
In the illustrated embodiments, the guide walls are arranged in the form of a labyrinth, which promotes the separation of oil from the crankcase gases as the gases flow therealong. Alternatively, the oil separator may be a cyclone type oil separator, wherein the guide wall is a coil that defines a spiral-shape flow path that extends between the inlet and the outlet of the housing. It should be appreciated by those having ordinary skill in the art that other types of oil separators may be packaged within the housing. Alternatively, the oil separator may incorporate more than one type of oil separating arrangement within the housing, such as a combination between labyrinth and cyclone type oil separating arrangements.
The invention has been described in an illustrative manner. It is, therefore, to be understood that the terminology used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings. Thus, within the scope of the appended claims, it is clear that the invention may be practiced other than as specifically described.
