# US 2012/0073541 A1 · Fuel injection spray patterns for opposed-piston engines

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- Number: US 2012/0073541 A1
- Document ID: US20120073541A1
- Status: Published application
- Kind: A1
- Application number: 13/136,954
- Filed: 2011-08-15
- Published: 2012-03-29
- Earliest claimed: 2010-08-16
- Assignees: Achates Power, Inc.
- Inventors: Kevin B. Fuqua; Fabien G. Redon; Huixian Shen; Michael H. Wahl
- Web page: https://patentgrep.com/patent/US20120073541A1

## CPC

- F01B 7/08: with side rods
- F01B 7/02: with oppositely reciprocating pistons
- F01B 7/12: using rockers and connecting-rods
- F02B 23/0621: {Squish flow}
- F02B 23/0624: {Swirl flow}
- F02B 23/063: {the combustion space in the piston interacting fluid dynamically with the cylinder head, the injector body or the cylinder wall (F02B23/04 takes precedence)}
- F02B 23/0633: {the combustion space being almost completely enclosed in the piston, i.e. having a small inlet in comparison to its volume}
- F02B 23/0645: {Details related to the fuel injector or the fuel spray}
- F02B 23/0651: {the fuel spray impinging on reflecting surfaces or being specially guided throughout the combustion space}
- F02B 23/0663: {having multiple injectors per combustion chamber}
- F02B 23/0675: {the combustion space being substantially spherical, hemispherical, ellipsoid or parabolic}
- F02B 23/0678: {Unconventional, complex or non-rotationally symmetrical shapes of the combustion space, e.g. flower like, having special shapes related to the orientation of the fuel spray jets}
- F02B 75/04: Engines with variable distances between pistons at top dead-centre positions and cylinder heads
- F02B 75/28: Engines with two or more pistons reciprocating within same cylinder or within essentially coaxial cylinders (arranged oppositely relative to main shaft F02B75/24)
- F02B 75/282: {the pistons having equal strokes}
- F02B 75/32: Engines characterised by connections between pistons and main shafts and not specific to preceding main groups
- F02M 61/14: Arrangements of injectors with respect to engines; Mounting of injectors
- F16C 33/04: Brasses; Bushes; Linings
- F02B 2275/48: Tumble motion in gas movement in cylinder
- F02M 61/1806: {characterised by the arrangement of discharge orifices, e.g. orientation or size}
- Y02T 10/12: Improving ICE efficiencies
- F01B: MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES (of rotary-piston or oscillating-piston type F01C; of non-positive-displacement type F01D; internal-combustion engines F02B; combustion-product engine plants F02G; machines or engines, other than of positive-displacement type, for liquids F03B; positive-displacement engines driven by liquids F03C; wind motors F03D; positive-displacement machines for liquids F04B; rotary-piston, or oscillating-piston, positive-displacement machines for liquids F04C)
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A combustion chamber for an opposed-piston engine includes a squish zone defined between circumferential peripheral areas of opposing end surfaces of the pistons, a cavity defined by one or more bowls in the end surfaces, and at least one injection port that extends radially through the squish zone into the cavity. The cavity has a cross-sectional shape that imposes a tumbling motion on air flowing from the squish zone into the cavity. Opposing spray patterns of fuel are injected into the combustion chamber. In some aspects, the opposing spray patterns are injected along a major axis of the combustion chamber.

## Claims

### Claim 1

A method for operating an internal combustion engine including at least one cylinder with longitudinally-separated exhaust and intake ports, a pair of pistons disposed in opposition to one another in a bore of the cylinder, and a combustion chamber defined in the bore between end surfaces of the pistons, in which charge air is admitted into the bore from the intake port as the pistons move from respective bottom dead center positions in the bore, a tumble component is added to the motion of the air in the combustion chamber, and spray patterns of fuel are injected into the combustion chamber in opposing radial directions of the cylinder.

### Claim 2 (depends on 1)

The method of claim 1, wherein the tumble component is added to the motion of the air as the pistons approach top dead center positions in the bore.

### Claim 3 (depends on 2)

The method of claim 2, in which each spray pattern includes a plurality of plumes disposed in an array with respect to an axis of injection.

### Claim 4 (depends on 3)

The method of claim 3, in which the spray patterns are rotationally oriented so as to orient the plumes of the spray patterns in opposition.

### Claim 5 (depends on 3)

The method of claim 3, in which the spray patterns are rotationally oriented so that the plumes of the spray patterns are interdigitated.

### Claim 6 (depends on 1)

The method of claim 1, wherein the charge air is swirled as it is admitted into the bore and the tumble component is added to a swirling motion of the air as the pistons approach top dead center positions in the bore.

### Claim 7 (depends on 6)

The method of claim 6, in which each spray pattern includes a plurality of plumes disposed in an array with respect to an axis of injection.

### Claim 8 (depends on 7)

The method of claim 7, in which the spray patterns are rotationally oriented so as to orient the plumes of the spray patterns in opposition.

### Claim 9 (depends on 7)

The method of claim 7, in which the spray patterns are rotationally oriented so that the plumes of the spray patterns are interdigitated.

### Claim 10

A method for operating an internal combustion engine including at least one cylinder with longitudinally-separated exhaust and intake ports, and a pair of pistons disposed in opposition to one another in a bore of the cylinder, by admitting air into the bore through the intake port as the pistons move from respective bottom dead center positions in the bore, causing a tumbling motion in the charge of air between opposing end surfaces of the pistons as the pistons move toward respective top dead center positions in the bore, and side-injecting opposing spray patterns of fuel into the charge air between the opposing end faces.

### Claim 11 (depends on 10)

The method of claim 10, including moving the opposing bowls on facing end surfaces of the pistons together to define a combustion chamber having an elongated ellipsoidal shape.

### Claim 12 (depends on 11)

The method of claim 11, in which injecting a charge of fuel into the charge of air includes injecting the fuel along a major axis of the combustion chamber.

### Claim 13 (depends on 11)

The method of claim 11, in which each spray pattern includes a plurality of plumes disposed in an array with respect to an axis of injection.

### Claim 14 (depends on 13)

The method of claim 13, in which the spray patterns are rotationally oriented so as to orient the plumes of the spray patterns in opposition.

### Claim 15 (depends on 13)

The method of claim 13, in which the spray patterns are rotationally oriented so that the plumes of the spray patterns are interdigitated.

### Claim 16 (depends on 10)

The method of claim 10, in which a swirling motion is imposed on the air admitted into the bore.

### Claim 17 (depends on 16)

The method of claim 16, including moving the opposing bowls on facing end surfaces of the pistons together to define a combustion chamber having an elongated ellipsoidal shape having a major axis.

### Claim 18 (depends on 17)

The method of claim 17, in which injecting a charge of fuel into the charge of air includes injecting the fuel along the major axis.

### Claim 19 (depends on 18)

The method of claim 18, in which each spray pattern includes a plurality of plumes disposed in an array with respect to an axis of injection.

### Claim 20 (depends on 19)

The method of claim 19, in which the spray patterns are rotationally oriented so as to orient the plumes of the spray patterns in opposition.

### Claim 21 (depends on 19)

The method of claim 19, in which the spray patterns are rotationally oriented so that the plumes of the spray patterns are interdigitated.

### Claim 22

A method for operating an internal combustion engine including at least one cylinder with longitudinally-separated exhaust and intake ports, and a pair of pistons disposed in opposition for reciprocating in a bore of the cylinder, by forming a combustion chamber having an elongated ellipsoidal shape between the end surfaces of the pistons as the pistons move toward respective top dead center positions in the bore, providing squish flows of charge air into the combustion chamber in directions that are skewed with respect to a major axis of the elongated ellipsoidal shape, generating at least one tumbling motion of charge air in the combustion chamber in response to the squish flows and swirling charge air, and injecting opposing spray patterns of fuel into the combustion chamber.

### Claim 23 (depends on 22)

The method of claim 22, in which injecting opposing spray patterns of fuel into the combustion chamber includes injecting the spray patterns of fuel along the major axis.

### Claim 24 (depends on 23)

The method of claim 23, in which each spray, pattern includes a plurality of plumes disposed in an array with respect to an axis of injection.

### Claim 25 (depends on 24)

The method of claim 24, in which the spray patterns are rotationally oriented so as to orient the plumes of the spray patterns in opposition.

### Claim 26 (depends on 25)

The method of claim 25, in which the plumes include four plumes.

### Claim 27 (depends on 25)

The method of claim 25, in which generating at least one tumbling motion includes generating a first tumbling motion about a major axis and generating a second tumbling motion about an axis orthogonal to the major axis.

### Claim 28 (depends on 24)

The method of claim 24, in which the spray patterns are rotationally oriented so that the plumes of the spray patterns are interdigitated.

### Claim 29 (depends on 28)

The method of claim 28, in which the plumes include four plumes.

### Claim 30 (depends on 28)

The method of claim 28, in which generating at least one tumbling motion includes generating a first tumbling motion about a major axis and generating a second tumbling motion about an axis orthogonal to the major axis.

### Claim 31 (depends on 24)

The method of claim 24, in which the spray patterns are rotationally oriented in a range between an orientation in which the plumes of the spray patterns in opposition and an orientation in which the plumes of the spray patterns are interdigitated.