Patent Publication Number: US-8534424-B2

Title: Automotive turbocharger with integral lubricating oil filter

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a turbocharger having a dedicated oil filter for removing contaminants from lubricating oil flowing into the turbocharger. 
     2. Disclosure Information 
     Turbochargers have been used with internal combustion engines for many years. Most turbochargers typically employ one or more bearings which permit operation of the turbocharger at extremely high rotational speeds and under very demanding thermal conditions. Needless to say, turbocharger bearings are very precisely constructed and, as such, are subject to severe damage if fouled by foreign matter. The present inventors have determined that a likely cause for turbocharger failure is insufficient cleanliness within an engine at initial startup. During machining of an engine, and particularly during the machining of various passages within a cylinder block, crankshaft, and other parts, particles of metal and other detritus are generated. Such particles, if not removed during subsequent washing operations, will have the capacity to quickly damage turbocharger bearings if the particles are carried into the turbocharger by lubricating oil flowing into the turbocharger. 
     Unfortunately, it is not possible for turbochargers to have a sealed lubrication system because, unlike superchargers, turbochargers are subjected to such thermal stress that it is necessary that oil be circulated from the engine&#39;s primary lubrication system to manage the heat buildup within the turbocharger. 
     It would be desirable to provide a filter for intercepting foreign matter flowing in lubrication oil to a turbocharger, so as to avoid damage to the turbocharger. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the invention, an automotive turbocharger includes a housing and a rotating assembly mounted within the housing. A lubrication passage admits lubricating oil into the turbocharger, and a lube oil filter mounted within a portion of the lubrication passage filters the oil such that all oil entering the turbocharger will pass through the lube oil filter. According to another aspect of the present invention, the lubrication passage is furnished with oil under pressure from an engine lubrication system. The lube oil filter may be either attached to an external port formed as a portion of the lubrication passage which admits lubricating oil into the turbocharger. This external port may be configured within a turbocharger mounting pedestal. As yet another alternative according to the present invention, a turbocharger lube oil filter may include a filter element housed completely within a lubrication passage extending within the turbocharger, with the filter element and the lubrication passage defining an outer annular inflow passage and an axially directed outflow passage. 
     According to another aspect of the present invention, a cartridge type of filter element may also be housed within a portion of a lubrication passage formed within a turbocharger mounting pedestal. 
     According to another aspect of the present invention, a turbocharger mounting pedestal having a filter as described above, receives lubricating oil directly from a lubrication passage configured within a cylinder block of an engine. 
     It is an advantage of an automotive turbocharger according to the present invention that the service life of the turbocharger will be enhanced because the turbocharger receives only oil which has been filtered at the last possible moment, so as to prevent contamination of the oil from machining debris, carbon particles, or any other type of dirt or foreign matter which can be carried within lube oil circulating within the engine&#39;s primary lubrication system. 
     It is yet another advantage of a turbocharger according to the present invention that the oil filter cartridge may be changed during operation of scheduled service of the engine, so as to further prolong the life of the turbocharger, without the necessity of removing the turbocharger from the engine. 
     Other advantages, as well as features, of the present invention will become apparent to the reader of this specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially schematic sectional view of a turbocharger having an oil filter according to an aspect of the present invention. 
         FIG. 2  is a partially schematic sectional view of a turbocharger having an oil filter according to another aspect of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in  FIGS. 1 and 2 , turbocharger  10  includes a housing  14  and a rotating assembly  18 , which typically includes a compressor and a turbine on a common shaft supported by one or more bearings. A lubrication passage,  22 , admits lubricating oil into turbocharger  10 . Two types of lube oil filters are illustrated, with both being mounted within a portion of lubrication passage  22  so that all oil entering the turbocharger will pass through the lube oil filter. 
       FIG. 1  illustrates a screw-in filter,  26 , which is threaded into an external port,  46 , formed as a portion of lubrication passage  22 . Lubricating oil enters first end,  26 A, of filter  26 , and exits through second end,  26 B, of filter  26 , before passing into lubrication passage  22 . Oil within lubrication passage  22  flows upwardly through turbocharger mounting pedestal  50  and into housing  14 , where it lubricates the bearings (not shown) of turbocharger  10 . In general, filter  26  is preferably configured to remove particles having a size greater than about 20 microns. 
       FIG. 2  illustrates another embodiment of a turbocharger filter according to the present invention which a cartridge type of filter element,  30 , is housed within lubrication passage  22 . Element  30  has a discharge end  30 A, which allows oil to flow into the ascending portion of lubrication passage  22 . This ascending portion is shown at  22 A in  FIG. 2 . Oil flowing into passage  22 A through inlet port  24  originates from engine oil pump  34  and primary filter  36 . Oil leaving filter  36  flows through high-pressure oil passage  38 , which is formed within cylinder block  42 . A purpose of filter  30  is to remove any contaminants lurking about passage  38  downstream of primary filter  36 . With the embodiments of both  FIGS. 1 and 2 , oil returns from turbocharger  10  to the engine&#39;s lubrication system through return passage  58  formed in pedestal  50 . 
     Oil filter cartridge  30  is confined within passage  22  by a plug,  54 , which may be fastened removably, so as to permit periodic renewal or cleaning of cartridge  30 . In any event, lubricating oil flowing about the outer periphery of cartridge  30  first passes radially inward through the walls of cartridge  30 . Oil having flowed radially inwardly then passes axially outward through end  30 A of cartridge  30  and into portion  22 A of lubrication passage  22 . As noted above, plug  54  may be threaded, and therefore removable, allowing extraction and replacement of cartridge  30  during servicing of an engine equipped with the present turbocharger lubrication oil filter. With both of the illustrated embodiments, all oil entering turbocharger  10  will be filtered at the last possible moment, thereby enhancing turbocharger useful life and performance. Those skilled in the art will appreciate in view of this disclosure that several different types of filter media may be employed with the present invention. For example, sintered metal, folded paper, wire mesh, and yet other types of filters are available and may be specified according to the needs of any particular engine and turbocharger. This detail is beyond the scope of the present invention. 
     The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and fall within the scope of the invention. Accordingly the scope of legal protection afforded this invention can only be determined by studying the following claims.