Patent Publication Number: US-8973552-B2

Title: Integral oil system

Description:
BACKGROUND 
     The present disclosure relates to an oil management system and more particularly to an integrated oil system. 
     Engine oil management systems are typically either a wet-sump or dry-sump arrangements. In a dry-sump system, the oil is contained in a separate tank, and circulated through the engine by pumps. In a wet-sump system, the oil is located in a sump, which is an integral part of the engine. 
     A main component of a wet-sump system is an oil pump, which draws oil from the sump and routes it to the engine. After the oil passes through the engine, it returns to the sump. An oil pump also supplies oil pressure in a dry-sump system, but the source of the oil is a separate oil tank, located external to the engine. After oil is routed through the engine, it is pumped from the various locations in the engine back to the oil tank by scavenge pumps. Dry sump systems allow for a greater volume of oil to be supplied to the engine, which are suitable for engines such as an aircraft in a pusher configuration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various features will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiment. The drawings that accompany the detailed description can be briefly described as follows: 
         FIG. 1  is a general perspective view of an exemplary aircraft embodiment for use with the present disclosure; 
         FIG. 2  is a schematic partial phantom view of an engine for use with the aircraft of  FIG. 1 ; 
         FIG. 3  is a perspective view of the engine; 
         FIG. 4  is a side schematic view of the engine with an integral oil system in accords with one non-limiting embodiment; 
         FIG. 5  is a section view of the engine through the integral oil system illustrating key oil system elements; 
         FIG. 6  is a side view schematic of the engine illustrating the location of the oiling system between the first and second rotor housing; 
         FIG. 7  is a side view with another non-limiting embodiment where water feed-throughs are distributed across the oil cooler; 
         FIG. 8  is a section view of the of the integral oil system of the other non-limiting embodiment depicted in  FIG. 7   
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  schematically illustrates an air vehicle  10  with a pusher prop propulsion system  12 . The pusher prop propulsion system  12  generally includes an engine  14  which drives a rotor hub  16  with a multiple of prop blades  18  for rotation about an axis of rotation A. The rotor hub  16  may be driven directly by the engine  14  or through a geared architecture of various configurations. Although a propeller system typical of a fixed wing aircraft is illustrated in the disclosed non-limiting embodiment, it should be understood that various air vehicle, rotor blade and propeller system configurations will also benefit herefrom. 
     With reference to  FIG. 2 , the engine  14  in the disclosed non-limiting embodiment is a rotary engine that includes a compression section  22  and a power section  24 . Although a rotary engine is illustrated in the disclosed non-limiting embodiment, it should be understood that other engines such as gas turbine and internal combustion engines may alternatively benefit therefrom. 
     An intake port  26  communicates ambient air to the compression section  22  and an exhaust port  28  communicates exhaust products therefrom. A first transfer duct  30  and a second transfer duct  32  communicate between the compression section  22  and the power section  24  such that the exhaust of the power section  24  may be returned to the compression section  22  to provide power recovery and increasing efficiency which provides a cycle within what is referred to herein as a compound rotary engine of the Wankel-type that operates with a heavy fuel such as JP-8, JP-4, diesel or other. 
     A single shaft  38  which rotates about the axis of rotation A includes aligned eccentric cams  40 ,  42  which drive a respective first rotor  44  and second rotor  46  which are driven in a coordinated manner by the shaft  38 . The first rotor  44  and second rotor  46  are respectively rotatable in volumes  48 ,  50  formed by a stationary first rotor housing  52  and a stationary second rotor housing  54 . The surfaces of the volumes  48 ,  50  in planes normal to the axis of rotation A are substantially those of a two-lobed epitrochoid while the surfaces of the rotors  44 ,  46  in the same planes are generally a Reuleaux triangle which mates with the inner envelope of the two-lobed epitrochoid. 
     A fuel system  36  includes fuel injectors  36 A,  36 B in communication with the second rotor volume  50  generally opposite the side thereof where the transfer ducts  30 ,  32  are situated in one non-limiting embodiment. The fuel system  36  supplies fuel into the second rotor volume  50 . The first rotor volume  48  in one non-limiting embodiment provides a greater volume than the second rotor volume  50 . The first rotor housing  52  and the second rotor housing  54  may be formed in an independent or integral manner to define an engine housing assembly  56  with various fin type and other cooling features ( FIG. 3 ). 
     In operation, air enters the engine  14  through the intake port  26 . The first rotor  44  provides a first phase of compression and the first transfer duct  30  communicates the compressed air from the first rotor volume  48  to the second rotor volume  50 . The second rotor  46  provides a second phase of compression, combustion and a first phase of expansion, then the second transfer duct  32  communicates the exhaust gases from the second rotor volume  50  to the first rotor volume  48 . The first rotor  44  provides a second phase of expansion to the exhaust gases, and the expanded exhaust gases are expelled though the exhaust port  28 . As each rotor face completes a cycle every revolution and there are two rotors with a total of six faces, the engine produces significant power within a relatively small displacement. 
     With reference to  FIG. 3 , an exhaust system  60  may be arranged in conformal arrangement between the engine housing assembly  56  and an engine mounted conformal radiator  66 . An oil management system  68  generally includes an oil pump  70 , a water pump  72 , and an oil cooler/filtration/dearation assembly  74 . The oil cooler/filter/dearation assembly  74  may be arranged between the first rotor  44  and second rotor  46  of the respective compression section  22  and power section  24  generally between the first rotor housing  52  and the second rotor housing  54 . The oil cooler assembly  74  also provides structural load carrying capability supporting the side walls of the engine housings on either side within a compact package that is light in weight due to integration with the engine housing assembly  56  which minimizes auxiliary components. ( FIG. 4 ) It should be understood that various housing configurations which integrate the oil cooler assembly  74  may alternatively or additionally be provided. 
     With reference to  FIG. 5 , the oil cooler assembly  74  includes an oil reservoir  76  that receives a replaceable oil filter  78 . The oil reservoir  76  may be cooled by an engine coolant flow circuit  80 ,  88  ( FIGS. 6 ,  7 ) which in the disclosed non-limiting embodiment is a water circuit ( FIG. 5 ). Various coolant fins  76 F (illustrated schematically) in thermal communication with the coolant flow circuit  80  are located within the oil reservoir  76 . It should be understood that various passages and/or fins or various configurations may be provided. In another disclosed non-limiting embodiment, an air cooled system may additionally or alternatively be utilized. 
     The oil reservoir  76  receives oil from an oil circuit  82  (illustrated schematically) to provide a thermal transfer exchange with the coolant flow circuit  80 . The oil circuit  82  may be used to cool various engine components, for example, bearing elements. The oil reservoir receives oil from the oil circuit  82  through an oil inlet  84  in communication with the oil filter  78  which is located above an oil discharge  86 . The oil reservoir  76  in the disclosed non-limiting embodiment may be considered a dry sump system with the oil pump  70  and a secondary external oil reservoir (not shown) such that oil passage through the oil reservoir  76  facilitates separation or dearation of any entrained gases from the oil before reuse. 
     With reference to  FIG. 6 , the coolant flow circuit  80  is integral to the engine housing assembly  56  to cool the first rotor housing  52  and the second rotor housing  54 . Between the first rotor housing  52  and the stationary second rotor housing  54 , the coolant flow circuit  80  passes through the oil reservoir  76  in a multiple of passages  88  located in this non-limiting embodiment around the shaft  38 . That is, the multiple of passages  88  are generally arranged in an annulus in thermal communication with the oil circuit  82 . In addition, the coolant flow circuit  80  may be utilized to facilitate oil preheat with a selectively operable heater system H (illustrated schematically) in communication with the coolant flow circuit  80 . 
     With reference to  FIG. 7 , a coolant flow circuit  80 ′ according to another non-limiting embodiment includes a multiple of passages  88 ′ which extend through the oil reservoir  76  ( FIG. 8 ). It should be understood that various passage arrangements may alternatively or additionally be provided. 
     It should be understood that relative positional terms such as “forward,” “aft,” “upper,” “lower,” “above,” “below,” and the like are with reference to the normal operational attitude of the vehicle and should not be considered otherwise limiting. 
     It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit herefrom. 
     Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present disclosure. 
     The foregoing description is exemplary rather than defined by the limitations within. Various non-limiting embodiments are disclosed herein, however, one of ordinary skill in the art would recognize that various modifications and variations in light of the above teachings will fall within the scope of the appended claims. It is therefore to be understood that within the scope of the appended claims, the disclosure may be practiced other than as specifically described. For that reason the appended claims should be studied to determine true scope and content.