Gas engine and ship provided with same

Abstract

The purpose of the present invention is to provide a gas engine and a ship provided with the same, the gas engine making it is possible to ensure a distance that enables fuel and an oxidizing agent to mix, and to evenly mix the oxidizing agent and the fuel even if the flow rate of gas traveling towards intake pipes varies. A gas engine (1) comprises: an intake passage (10) through which a gas flows; a plurality of intake pipes (12A, 12B) where the intake passage (10) branches apart at a branching section (14) that is downstream in the gas flow direction, the intake pipes opening to a cylinder (16) at the downstream end; and a fuel injection means (31) that injects fuel into the intake passage (10). The fuel injection means (31) is provided upstream of the branching section (14) in the gas flow direction, and injects varying quantities of fuel into the plurality of intake pipes (12A, 12B).

Claims

1. A gaseous-fueled engine comprising: an intake air channel forming an air channel through which air flows; first and second intake pipes in which the intake air channel is branched at a branching portion, the first and second intake pipes being located downstream in a flow direction with respect to the branching portion and being open to a cylinder in a downstream end; and fuel injecting means for injecting fuel into the intake air channel, wherein the first and second intake pipes are designed so that, in the intake air channel, an air flow directed toward the first intake pipe is faster than an air flow directed toward the second intake pipe, and the fuel injecting means is disposed upstream of the branching portion in the gas flow direction, and is designed to inject different amounts of the fuel into the first and second intake pipes, so that an amount of the fuel injected into the first intake pipe is larger than an amount of the fuel injected into the second intake pipe and a concentration of the mixed gas of air and fuel to be supplied via the first intake pipe to the cylinder and a concentration of the mixed gas of air and fuel to be supplied via the second intake pipe to the cylinder are made uniform.

2. The gaseous-fueled engine according to claim 1, wherein the fuel injecting means includes a single injecting pipe having injecting ports formed in a first row and second injecting ports formed in a second row, and each port has an opening area and a total opening area of the first injecting ports directed in a direction toward the first intake pipe is different from a total opening area of the second injecting ports directed toward the second intake pipe.

3. The gaseous-fueled engine according to claim 2, wherein in the plurality of injecting ports belonging to the injecting pipe, the first injecting ports directed in the direction toward the first intake pipe have the same area that is different from the same opening area of the second injecting ports directed in the direction toward the second intake pipe.

4. The gaseous-fueled engine according to claim 3, wherein the fuel injecting means includes a rotation mechanism configured to rotate the injecting pipe around an axis.

5. The gaseous-fueled engine according to claim 3, wherein the plurality of injecting ports are formed toward a downstream side in the gas flow direction.

6. The gaseous-fueled engine according to claim 2, wherein the first and second injecting ports have the same opening area, and the number of the first injecting ports directed in the direction toward the first intake pipe is different from the number of the second injecting ports directed in the direction toward the second intake pipe.

7. The gaseous-fueled engine according to claim 6, wherein the fuel injecting means includes a rotation mechanism configured to rotate the injecting pipe around an axis.

8. The gaseous-fueled engine according to claim 6, wherein the plurality of injecting ports are formed toward a downstream side in the gas flow direction.

9. The gaseous-fueled engine according to claim 2, wherein the fuel injecting means includes a rotation mechanism configured to rotate the injecting pipe around an axis.

10. The gaseous-fueled engine according to claim 2, wherein the plurality of injecting ports are formed toward a downstream side in the gas flow direction.

11. A ship comprising: the gaseous-fueled engine according to claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a longitudinal sectional view illustrating a configuration in the vicinity of a cylinder of a gas engine according to a first embodiment of the present invention.

(2) FIG. 2 is a plan view of a cylinder head of the gas engine according to the first embodiment of the present invention.

(3) FIG. 3 is a perspective view of an intake air channel included in the gas engine according to the first embodiment of the present invention.

(4) FIG. 4 is a plan view of FIG. 3.

(5) FIG. 5A is a plan view of a jetting pipe included in the gas engine according to the first embodiment of the present invention, FIG. 5B is a developed view, and FIG. 5C is a longitudinal sectional view taken along line I-I.

(6) FIG. 6A is a plan view of a jetting pipe included in a gas engine according to a second embodiment of the present invention, FIG. 6B is a developed view, and FIG. 6C is a longitudinal sectional view taken along line II-II.

(7) FIG. 7 is a plan view of an intake air channel included in a gas engine according to a third embodiment of the present invention.

(8) FIG. 8A is a plan view of a jetting pipe rotated around an axis, FIG. 8B is a developed view, and FIG. 8C is a longitudinal sectional view taken along line III-III.

(9) FIG. 9 is a view illustrating an example of a map based on a rotation speed and an output.

DESCRIPTION OF EMBODIMENTS

(10) Hereinafter, a gas engine according to an embodiment of the present invention will be described with reference to FIGS. 1 to 9.

First Embodiment

(11) Hereinafter, a gas engine according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5.

(12) First, a configuration of a gas engine 1 will be described.

(13) FIG. 1 illustrates a configuration in the vicinity of a cylinder 16 included in the gas engine 1. The cylinder 16 has a cylindrical shape, and a cylinder head 16a is attached to an upper portion thereof. A piston (not illustrated) that reciprocates and slides inside the cylinder 16 is accommodated inside the cylinder 16. In addition, the cylinder 16 internally has a combustion chamber 18 defined by an inner wall of the cylinder 16 and the piston.

(14) One end (end portion on a downstream side of a gas flow) of curved intake pipes 12A and 12B communicating with an intake air channel 10 (to be described later) is connected to intake ports 22A and 22B disposed in an upper portion of the cylinder head 16a attached to the cylinder 16 (refer to FIG. 2).

(15) Intake valves 20A and 20B having an outer shape of a funnel are installed in connecting portions between the intake ports 22A and 22B of the cylinder head 16a and the intake pipes 12A and 12B. The intake valves 20A and 20B are biased to an upper side illustrated in FIG. 1 by a mechanism (not illustrated) so that a tapered portion having a funnel shape blocks the intake ports 22A and 22B disposed in the cylinder head 16a from a lower side illustrated in FIG. 1. However, if necessary (for example, when air is taken to the cylinder 16), the intake valves 20A and 20B are pushed down into the cylinder 16. In this manner, the intake pipes 12A and 12B can communicate with the combustion chamber 18.

(16) The intake air channel 10 forms an air channel extending in an upward-downward direction illustrated in FIG. 1. In addition, fuel jetting means 31 for jetting the fuel gas is installed inside the intake air channel 10.

(17) As illustrated in FIG. 1, the intake pipes 12A and 12B are formed as the air channel having a curved pipe shape in which the intake air channel 10 is branched in a branching portion 14 in two directions. In the present embodiment, the intake pipe having a longer path illustrated in FIG. 1 is the intake pipe 12A, and the intake pipe having a shorter path is the intake pipe 12B.

(18) Next, the fuel jetting means 31 will be described.

(19) In the present embodiment, the fuel jetting means 31 for jetting the fuel gas into the intake air channel 10 can jet respectively different amounts of the fuel gas to the intake pipe 12A and the intake pipe 12B.

(20) Hereinafter, the fuel jetting means 31 will be described in detail.

(21) As illustrated in FIGS. 3 and 4, the fuel jetting means 31 includes one jetting pipe 40. The jetting pipe is inserted to be perpendicular to the intake air channel 10 along an axial direction so that the jetting pipe 40 is located in the vicinity of the center inside the intake air channel 10.

(22) As illustrated in FIGS. 5A, 5B, and 5C, the jetting pipe 40 has a plurality of jetting ports 42 bored to be respectively directed in two directions, in two rows in the axial direction and symmetrically with respect to the axis (refer to an angle θ formed with respect to a horizontal plane illustrated in FIG. 5C). In a case of FIGS. 5A, 5B), and 5C), the plurality of jetting ports directed in one direction are set as jetting ports 42A, and the plurality of jetting ports directed in the other direction are set as jetting ports 42B. The number of the jetting ports 42A and the number of the jetting ports 42B are the same as each other. In addition, areas of the plurality of jetting ports 42A are all the same, and areas of the plurality of jetting ports 42B are all the same. For example, the one direction described here is a direction to the gas flowing toward the intake pipe 12A, and for example, the other direction is a direction to the gas flowing toward the intake pipe 12B.

(23) An area of an opening of the jetting port 42A is set to be larger than an area of an opening of the jetting port 42B. In addition, as described above, the number of the jetting ports 42A and the number of the jetting ports 42B are the same as each other. In addition, as described above, areas of the plurality of jetting ports 42A are all the same, and areas of the plurality of jetting ports 42B are all the same. In this manner, a total area of the plurality of jetting ports 42A directed in one direction is different from a total area of the plurality of jetting ports 42B directed in the other direction. In other words, the total area of the plurality of jetting ports 42A directed to the gas flowing toward the intake pipe 12A is larger than the total area of the plurality of jetting ports 42B directed to the gas flowing toward the intake pipe 12B. That is, much more fuel gas can be jetted to the gas flowing toward the intake pipe 12A.

(24) In the above description, the total area of the plurality of jetting ports 42A directed to the gas flowing toward the intake pipe 12A is set to be larger than the total area of the plurality of jetting ports 42B directed to the gas flowing toward the intake pipe 12B. However, a configuration is not particularly limited to a combination thereof. In practice, the total area of the plurality of jetting ports directed to the intake pipe having a high flow speed may be larger than the total area of the plurality of jetting ports directed in the other direction. The reason is apparent from the following fact. When the gas flow speed is high, the amount of the fuel gas flowing per unit time, that is, the amount of required fuel gas increases.

(25) Next, the gas flow of the gas engine 1 according to the present embodiment will be described.

(26) An intercooler (not illustrated) is installed below the intake air channel 10 illustrated in FIG. 1. The air cooled by the intercooler flows inside the intake air channel 10 from below the intake air channel 10, and flows toward the branching portion 14 side located above. In this case, the fuel gas is jetted from the fuel jetting means 31 inserted into the intake air channel 10 toward the air flowing inside the intake air channel 10. The air and the fuel gas jetted toward the air reach the branching portion 14, and thereafter, are guided to the intake pipe 12A and the intake pipe 12B.

(27) As described above, the total area of the plurality of jetting ports 42A directed to the gas flowing toward the intake pipe 12A is larger than the total area of the plurality of jetting ports 42B directed to the gas flowing toward the intake pipe 12B. Accordingly, much more fuel gas is jetted to the gas flowing toward the intake pipe 12A, and much less fuel gas is jetted to the gas flowing toward the intake pipe 12B.

(28) The air and the fuel gas are gradually mixed with each other as the air and the fuel gas flow inside the intake air channel 10 and inside the intake pipes 12A and 12B. The mixed gas progressively mixed inside the intake pipes 12A and 12B is guided to the combustion chamber 18 when the intake valves 20A and 20B are pushed down and the intake ports 22A and 22B are in an open state. In this case, shapes of flow paths are different from each other between the intake pipe 12A and the intake pipe 12B. Accordingly, the flow speeds of the mixed gas flowing therethrough are different from each other between the intake pipe 12A and the intake pipe 12B. Therefore, even inside the intake air channel 10, the flow speed of the mixed gas directed to the intake pipe 12A and the flow speed of the mixed gas directed to the intake pipe 12B are different from each other. Here, it is assumed that the flow speed of the mixed gas flowing inside the intake pipe 12A is higher than the flow speed of the mixed gas flowing inside the intake pipe 12B. That is, it is assumed that the flow speed of the mixed gas directed to the intake pipe 12A is higher than the flow speed of the mixed gas directed to the intake pipe 12B inside the intake air channel 10.

(29) The mixed gas of the air and the fuel gas is guided to the combustion chamber 18 after flowing through each of the intake pipes 12A and 12B. The mixed gas is ignited and combusted by an ignition device (not illustrated). At this time, in a case where the mixed gas guided from each of the intake pipes 12A and 12B has variations in fuel concentration, the mixed gas is not uniformly combusted in the combustion chamber 18. Therefore, there are possibilities of NOx generation, knocking generation, and an increase in non-combusted fuel gas.

(30) The present embodiment achieves the following advantageous effects.

(31) The fuel jetting means 31 is disposed upstream of the branching portion 14 in the gas flow direction. According to this configuration, compared to a case where the fuel is directly jetted to each of the intake pipes 12A and 12B located downstream of the intake air channel 10, a distance in which the air and the fuel gas can be mixed with each other is lengthened, and the air and the fuel gas are uniformly and easily mixed with each other.

(32) In addition, the fuel jetting means 31 can jet respectively different amounts of the fuel to the plurality of intake pipes 12A and 12B. For example, in a case where the flow speed of the mixed gas directed to the intake pipe 12A is higher than the flow speed of the mixed gas directed to the intake pipe 12B inside the intake air channel 10, the total area of the jetting ports 42A directed in the direction of the gas flowing toward the intake pipe 12A can be larger than the total area of the jetting ports 42B directed in the direction of the gas flowing toward the intake pipe 12B. In this manner, the amount of the fuel can be increased for the intake pipe 12A having the high flow speed of the mixed gas of the air and the fuel gas, and the amount of the fuel can be decreased for the intake pipe 12B having the low flow speed of the gas. In this manner, the fuel concentration of the mixed gas to be supplied to the combustion chamber 18 via each of the intake pipes 12A and 12B can be uniform regardless of the intake pipes 12A and 12B. Therefore, the mixed gas of the air and the fuel gas can be uniformly combusted in the combustion chamber 18. Therefore, it is possible to suppress phenomena such as NOx generation, knocking generation, and an increase in non-combusted fuel gas.

Second Embodiment

(33) Hereinafter, a second embodiment according to the present invention will be described with reference to FIG. 6. The present embodiment is different from the first embodiment in a form of the fuel jetting means, and other points are the same as each other. Therefore, only the points different from those according to the first embodiment will be described. The same reference numerals will be assigned to the same elements, and description thereof will be omitted.

(34) As illustrated in FIGS. 6A, 6B, and 6C, the jetting pipe 40 included in fuel jetting means 32 has the plurality of jetting ports 42 bored to be respectively directed in two directions, in two rows in the axial direction and symmetrically with respect to the axis (refer to the angle θ formed with respect to a horizontal plane illustrated in FIG. 6C). In a case of FIGS. 6A, 6B, and 6C, the plurality of jetting ports directed in one direction are set as the jetting ports 42A, and the plurality of jetting ports directed in the other direction are set as the jetting ports 42B. One area of the jetting ports 42A and one area of the jetting ports 42B is the same as each other. For example, the one direction described here is a direction to the gas flowing toward the intake pipe 12A, and for example, the other direction is a direction to the gas flowing toward the intake pipe 12B.

(35) The jetting ports 42A and 42B are bored so that the number of jetting ports 42A is larger than the number of jetting ports 42B. In addition, as described above, one area of the jetting ports 42A and one area of the jetting ports 42B is the same as each other. In this manner, a total area of the plurality of jetting ports 42A directed in one direction is different from a total area of the plurality of jetting ports 42B directed in the other direction. In other words, the total area of the plurality of jetting ports 42A directed to the gas flowing toward the intake pipe 12A is larger than the total area of the plurality of jetting ports 42B directed to the gas flowing toward the intake pipe 12B. That is, much more fuel gas can be jetted to the gas flowing toward the intake pipe 12A.

(36) In the above description, the total area of the plurality of jetting ports 42A directed to the gas flowing toward the intake pipe 12A is set to be larger than the total area of the plurality of jetting ports 42B directed to the gas flowing toward the intake pipe 12B. However, a configuration is not particularly limited to a combination thereof. In practice, the total area of the plurality of jetting ports directed to the intake pipe having a high flow speed may be larger than the total area of the plurality of jetting ports directed in the other direction. The reason is apparent from the following fact. When the gas flow speed is high, the amount of the fuel gas flowing per unit time, that is, the amount of required fuel gas increases. Here, it is assumed that the flow speed of the mixed gas flowing inside the intake pipe 12A is higher than the flow speed of the mixed gas flowing inside the intake pipe 12B. That is, it is assumed that the flow speed of the mixed gas directed to the intake pipe 12A is higher than the flow speed of the mixed gas directed to the intake pipe 12B inside the intake air channel 10.

(37) The present embodiment achieves the following advantageous effects.

(38) In a case where the flow speed of the mixed gas directed to the intake pipe 12A is higher than the flow speed of the mixed gas directed to the intake pipe 12B inside the intake air channel 10, the total area of the jetting ports 42A directed in the direction of the gas flowing toward the intake pipe 12A can be larger than the total area of the jetting ports 42B directed in the direction of the gas flowing toward the intake pipe 12B. In this manner, the amount of the fuel can be increased for the intake pipe 12A having the high flow speed of the mixed gas of the air and the fuel gas, and the amount of the fuel can be decreased for the intake pipe 12B having the low flow speed of the gas. In this manner, the fuel concentration of the mixed gas to be supplied to the combustion chamber 18 via each of the intake pipes 12A and 12B can be uniform regardless of the intake pipes 12A and 12B. Therefore, the mixed gas of the air and the fuel gas can be uniformly combusted in the combustion chamber 18. Therefore, it is possible to suppress phenomena such as NOx generation, knocking generation, and an increase in non-combusted fuel gas.

Third Embodiment

(39) Hereinafter, a third embodiment according to the present invention will be described with reference to FIG. 7. The present embodiment is different from the first and second embodiments in a form of the fuel jetting means, and other points are the same as each other. Therefore, only the points different from those according to the first and second embodiments will be described. The same reference numerals will be assigned to the same elements, and description thereof will be omitted.

(40) Fuel jetting means 33 includes a single jetting pipe 40 having a plurality of jetting ports 42 bored in a row in the axial direction. In addition, the jetting pipe 40 is disposed close to flowing gas having the higher flow speed, out of the gas flowing toward the intake pipe 12A and the gas flowing toward the intake pipe 12B.

(41) Here, it is assumed that the flow speed of the mixed gas flowing toward the intake pipe 12A is higher than the flow speed of the mixed gas flowing toward the intake pipe 12B. Furthermore, it is assumed that the gas mainly flows toward the intake pipe 12A below the axis extending rightward and leftward inside the intake air channel 10 illustrated in FIG. 7. Therefore, in FIG. 7, the jetting pipe 40 is disposed in the intake air channel 10 (intake air channel 10 below the axis extending rightward and leftward) through which the gas mainly flowing toward the intake pipe 12A flows.

(42) The present embodiment achieves the following advantageous effects.

(43) The jetting pipe 40 is disposed close to the gas flow having the high flow speed, out of the gas flows directed to the plurality of intake pipes 12A and 12B. In this manner, the amount of the fuel can be increased for the intake pipe 12A having the high gas flow speed, and the amount of the fuel can be decreased for the intake pipe 12B having the low gas flow speed. In this manner, the fuel concentration of the mixed gas to be supplied to the combustion chamber 18 via each of the intake pipes 12A and 12B can be uniform regardless of the intake pipes 12A and 12B. Therefore, the mixed gas of the air and the fuel gas can be uniformly combusted in the combustion chamber 18. Therefore, it is possible to suppress phenomena such as NOx generation, knocking generation, and an increase in non-combusted fuel gas.

(44) The fuel jetting means 31, 32, and 33 according to the first to third embodiments may include a rotation mechanism (not illustrated) rotatable around the axis of the jetting pipe 40 (refer to FIG. 8). In this manner, the fuel gas can be jetted in an optimum direction that promotes the air and the fuel gas to be mixed with each other. In this case, it is preferable that the rotation mechanism is driven by a servomotor that can optionally adjust a rotation angle of the jetting pipe 40 and can acquire information on the rotation angle. For example, the rotation angle is uniquely determined by a control unit (not illustrated) from an actual output and an actual rotation speed of the gas engine 1, based on a map (refer to FIG. 9) of the output and the rotation speed of the gas engine 1 which are prepared from data obtained in advance.

(45) In addition, it is preferable that the jetting port bored in the jetting pipe 40 included in the fuel jetting means 31, 32, and 33 according to the first to third embodiments is formed to face the downstream side in the gas flow direction. Specifically, a range of the angle θ or φ formed with respect to the horizontal plane illustrated in FIGS. 5C, 6C, and 8C may be 0° to 90°. According to this configuration, when the gas engine 1 has a low output, even in a case where the gas flows rearward from the cylinder 16 side, the fuel gas to be jetted from the plurality of jetting ports 42 is not jetted to the upstream side of the gas. Therefore, the fuel gas jetted from the plurality of jetting ports 42 are less likely to flow rearward to the upstream side. In this manner, it is possible to prevent the fuel gas from flowing rearward to the intercooler (not illustrated) installed on the downstream side of the gas.

(46) In addition, the configurations of the fuel jetting means 31, 32, and 33 according to the first to third embodiments can be respectively combined with each other. For example, the jetting pipe 40 included in the fuel jetting means 31 according to the first embodiment may be disposed close to the gas having the high flow speed, as in the fuel jetting means 33 according to the third embodiment.

(47) In view of a disposition relationship with other components (not illustrated) configuring the gas engine 1, in a case where the intake pipes 12A and 12B can be symmetrically disposed toward the intake ports 22A and 22B and the flow speed is uniform after the intake pipes 12A and 12B are branched, the amounts of the fuel to be jetted from the jetting ports 42A and 42B do not need to vary depending on the intake pipes 12A and 12B, and the same amount of the fuel may be jetted.

REFERENCE SIGNS LIST

(48) 1: gas engine 10: intake air channel 12A, 12B: intake pipe 14: branching portion 16: cylinder 16a: cylinder head 18: combustion chamber 20A, 20B: intake valve 22A, 22B: intake port 31, 32, 33: fuel jetting means 40: jetting pipe 42 (42A, 42B): jetting port