WO2010047960A2

WO2010047960A2 - Rotary engine with scarped pocket rotor

Info

Publication number: WO2010047960A2
Application number: PCT/US2009/059949
Authority: WO
Inventors: Calvin Q. Morrison
Original assignee: Pratt & Whitney Rocketdyne, Inc.
Priority date: 2008-10-21
Filing date: 2009-10-08
Publication date: 2010-04-29
Also published as: WO2010047960A3

Abstract

A rotor for a rotary engine includes a face having a scarped pocket which has a geometry based on a spray pattern of a fuel injector.

Description

ROTARY ENGINE WITH SCARPED POCKET ROTOR

BACKGROUND

[0001] The present disclosure claims priority to and incorporates herein United States Provisional Patent Application No. 61/107318, 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] Figures 6A and 6B are perspective view of a second rotor that includes a scarped pocket; [0011] Figure 7 is a schematic sectional view of the scarped pocket with a geometry shaped to accommodate the spray pattern S from one or more fuel injectors; and

[0012] Figure 8 is a side view of the second rotor with the scarped pocket which receives a fuel jet spray pattern.

DETAILED DESCRIPTION

[0013] 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.

[0014] 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). [0015] 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 a 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.

[0016] 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 2). The shaft completes one revolution for every cycle, so there are three (3) crank revolutions for each complete rotor 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.

[0017] Referring to Figure 6A and 6B, the depression 46D in each peripheral surface or face 46P of the second rotor 46 is a scarped pocket. The geometry of the scarped pocket 46P may be defined by an angled pocket wall 46Dp which is generally angled along axis A in response to a fuel jet spray pattern S from the fuel injectors 36A, 36B (Figure 7) between a near end section 46Dn and a far end section 46Dd which is displaced from the fuel injectors 36A, 36B. The angled pocket wall 46Dp essentially slopes away from the near end section 46Dn adjacent to the fuel injectors 36A, 36B. The near end section 46Dn is relatively shallow as compared to the far end section 46Dd which defines the deepest section of the depression 46D. The near end section 46Dn may be of a relatively constant depth prior to the angled pocket wall 46Dp. The near end section 46Dn facilitates movement of the air charge toward the far end section 46Dd along the angled pocket wall 46Dp. The far end section 46Dd is defined across the depth of the face 46P transverse to axis A. That is, the deepest section of the depression 46D relative to the face 46P is displaced the greatest distance from the fuel injector 36A, 36B (Figure 8) to centralize and channel the air charge.

[0018] It should be understood that the depression 46D may be oblong or generally frustro-triangular shaped to accommodate the fuel jet spray pattern S from one or more fuel injectors 36A, 36B to provide a relatively long path to increase pocket height and provide significant area for fuel jet expansion to facilitate fuel and air mixture. That is, the angled pocket wall 46Dp facilitates multi-jet cross flow fuel injection for controlled fuel distribution and heat release rates. The depression 46D is tailored to match the fuel jet expansion characteristics to provide high combustion efficiency to move air out of the regions that can otherwise not be fueled. That is, the depression 46D centralizes the air charge to facilitate the fuel and air mixture.

[0019] The depression 46D optimizes plume compatibility, preserves high compression ratios and directs mixing from injection for primary jet entrainment to facilitate a decrease in specific fuel consumption for low weight propulsion systems in vehicles such as Unmanned Aerial Vehicles.

[0020] 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.

[0021] 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.

[0022] 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.

Claims

CLAIMSWhat is claimed is:

1. A rotor for a rotary engine comprising: a face having a scarped pocket .

2. The rotor as recited in claim 1, wherein said scarped pocket includes an angled pocket wall which is generally angled in response to said spray pattern.

3 The rotor as recited in claim 1, wherein said scarped pocket includes an angled pocket wall which slopes away from a fuel injector which defines said spray pattern.

4. The rotor as recited in claim 1, wherein said scarped pocket is oblong.

5 . The rotor as recited in claim 1, wherein said scarped pocket accommodates a spray pattern from a multiple of fuel injectors.

6. A rotary engine comprising: at least one fuel injector which defines a spray pattern; and a rotor which defines a face having a scarped pocket with an angled pocket wall which is angled along said spray pattern.

7. The rotary engine as recited in claim 6, wherein said scarped pocket includes a deepest section transverse to an axis of rotation of said second rotor.

8. The rotary engine as recited in claim 6, wherein said scarped pocket includes an angled pocket wall which slopes away from said at least one fuel injector along an axis of rotation of said second rotor.

9. The rotary engine as recited in claim 6, wherein said scarped pocket is located in each of three faces of said rotor.

10. The rotary engine as recited in claim 6, wherein said at least one fuel injector comprises a multiple of fuel injectors, said scarped pocket accommodate a spray pattern from said multiple of fuel injectors.

11. The rotary engine as recited in claim 6, wherein said rotor is a second rotor in communication with a first rotor, said second rotor provides a second stage of compression, a combustion and a first stage of expansion, said first rotor provides a first stage of compression and a second stage of expansion, said first rotor and said second rotor rotated by a single shaft such that each apex of said respective first rotor and said second rotor are aligned.