ROTARY ENGINE WITH CONFORMAL INJECTOR NOZZLE TIP

BACKGROUND

[0001] The present disclosure claims priority to and incorporates United States Provisional Patent Application No. 61/107,322, filed October 21, 2008. [0002] The present disclosure relates to a rotary engine.

[0003] Engine technology provides various tradeoffs between power density and fuel consumption. Gas turbine engine technology provides reasonably high power densities, but at relatively small sizes, fuel consumption is relatively high and efficiencies are relatively low. Small diesel piston engines have reasonable fuel consumption but may be relatively heavy with power densities typically below approximately 0.5 hp/lb while equivalently sized four-stroke engines have power densities typically below approximately 0.8 hp/lb. Two- stroke engines have greater power densities than comparably sized four-stroke engines, but have relatively higher fuel consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] 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: [0005] Figure 1 is a schematic block diagram view of an exemplary rotary engine;

[0006] Figure 2 is a partial phantom view of an exemplary rotary engine; [0007] Figure 3 is a partially assembled view of the exemplary rotary engine of Figure 1 illustrating the first rotor section;

[0008] Figure 4 is a partially assembled view of the exemplary rotary engine of Figure 1 illustrating the second rotor section;

[0009] Figure 5 is an exploded view of the rotary engine;

[0010] Figure 6 is a partial sectional view of a rotor housing to illustrate the conformal fuel injector tip; and

[0011] Figure 7 is a partial sectional view of a rotor housing to illustrate the conformal fuel injector tip with a conformal sleeve.

DETAILED DESCRIPTION

[0012] Figure 1 schematically illustrates a rotary engine 20 having a first rotor section 22 and a second rotor section 24. The rotary engine 20 is based on a rotary, e.g., Wankel-type engine. An intake port 26 communicates ambient air to the first rotor 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 first rotor section 22 and the second rotor section 24. A fuel system 36 for use with a heavy fuel such as JP-8, JP-4, natural gas, hydrogen, diesel and others communicate with the second rotor section 24 of the engine 20. The engine 20 simultaneously offers high power density and low fuel consumption for various commercial, industrial, compact portable power generation, and aerospace applications.

[0013] Referring to Figure 2, the rotary engine 20 generally includes at least one shaft 38 which rotates about an axis of rotation A. The shaft 38 includes aligned eccentric cams 40, 42 (Figures 3 and 4) which drive a respective first rotor 44 and second rotor 46 which are driven in a coordinated manner by the same 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 (Figures 3 and 4). The fuel system 36, in one non-limiting embodiment, includes one or more fuel injectors with two fuel injectors 36A, 36B shown 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. It should be understood that other fuel injector arrangement, locations and numbers may alternatively or additionally be provided. 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. It should be understood that various housing configurations shapes and arrangements may alternatively or additionally be provided (Figure 5).

[0014] The first rotor 44 and the second rotor 46 have peripheral surfaces which include three circumferentially spaced apexes 44A, 46A respectively. Each apex 44A, 46A include an apex seal 44B, 46B, which are in a sliding sealing engagement with a peripheral surface 48P, 5OP of the respective volumes 48, 50. 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 substantially those of the three-lobed inner envelope of the two-lobed epitrochoid.

[0015] In operation, air enters the engine 20 through the intake port 26 (Figure 1). 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 (Figures 2 and 3). 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 (Figures 2 and 4). 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 (Figures 1 and X). The shaft 38 completes one revolution for every cycle, so there are three (3) crank revolutions for each complete rotor 44, 46 revolution. 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.

[0016] Referring to Figure 6, the fuel injectors 36A, 36B are located within the second rotor housing 54. Although the fuel injectors 36A, 36B are illustrated in particular positions in the disclosed non-limiting embodiment, it should be understood that the fuel injectors 36A, 36B may be located in other positions and orientations other than those illustrated.

[0017] A flush tip 36T of each fuel injector 36A, 36B is configured to be conformal with a peripheral surface 5OS of the second rotor volume 50 to minimize leakage and recirculation zones for improved engine efficiency and reduced local heating. The flush tip 36T is thereby directly tailored to the specific position and orientation in the second rotor housing 54 to be conformal with the peripheral surface 5OS. Notably, the flush tip 36T of fuel injector 36A may be different than the flush tip 36T of fuel injector 36B due to the respective position and orientation. That is, the flush tip 36T is specific to location. [0018] The flush tip 36T provides maximum support for the second rotor apex seal

46B to minimize leakage across the second rotor apex seal 46B and maintain the chamber pressure within the second rotor volume 50 which has heretofore been a consideration in the design of rotary engines.

[0019] The flush tip 36T may be integral to the fuel injector (Figure 6) or be at least partially formed by a separable sleeve 60 within which the flush tip 36T of each fuel injector

36A, 36B is mounted (Figure 7). That is, the sleeve 60 defines a flush tip 6OT which is also conformal with the peripheral surface 5OS.

[0020] In one non-limiting embodiment, the sleeve 60 is manufactured of a high conductivity material such as copper. The high conductivity material communicates heat to the second rotor housing 54 to reduce peak temperatures experienced by the fuel injector 36A, 36B.

[0021] In another non-limiting embodiment, the sleeve 60 is manufactured of an insulating material such as a ceramic. The insulating material protects the fuel injector 36A,

36B from the relatively high wall temperatures typical of air cooled housings. The fuel injector

36A, 36B being so insulated by the sleeve 60, are essentially self cooled by fuel flow therethrough.

[0022] 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. [0023] 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.

[0024] 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.