Patent Application
20170356385
The present invention relates to a technique of an engine.
Compressed-air starting is one known mechanism for starting engines. The compressed-air starting includes feeding compressed air into a cylinder with a starter valve, pressing down a piston with the compressed air thus fed, and increasing an engine speed to an engine speed high enough to start the engine.
Conventionally, the starter valve has been oriented toward a combustion chamber in a cylinder head and is arranged in parallel with or orthogonal to an axial direction of the cylinder. Unfortunately, the configuration in which the starter valve is arranged orthogonal to the axial direction of the cylinder involves an extra space (dead volume) formed in the combustion chamber (for example, a starting air discharge path in Patent Literature 1).
The configuration in which the starter valve is arranged in parallel with the axial direction of the cylinder requires a large thickness to separate the starter valve and a cooling water passage from each other in the cylinder head. Thus, the starter valve requires a large space to be disposed in the cylinder head. Reducing a space for providing the starter valve has been an important technical task for downsizing of the engine involving downsizing of the cylinder head.
PTL 1: Japanese Unexamined Patent Application Publication No. 2005-240813
An object of the present invention is to provide an engine in which a starter valve can be disposed in a space saving manner.
A solution to achieve the object described above is described below.
An engine according to the present invention includes a cylinder head in which a starter valve with which compressed air is fed to a combustion chamber is provided and a cooling water passage is formed. The starter valve is arranged in parallel with an axial direction of a cylinder while being fit in a sleeve. An outer circumferential surface of the sleeve forms a part of a wall surface of the cooling water passage.
In the engine according to the present invention, the sleeve may be fit in a starter valve insertion hole formed in the cylinder head, an air passage orthogonal to an axial direction of the starter valve insertion hole may be formed in the cylinder head, and an end surface on one side of the sleeve may form a part of a wall surface of the air passage.
In the engine according to the present invention, a step portion that engages with a step portion of the starter valve insertion hole may be formed on an outer circumference of the sleeve.
In the engine according to the present invention, the starter valve can be disposed in a space saving manner.
A configuration of an engine 100 is described with reference to
The engine 100 is an embodiment of an engine according to the present invention. The engine 100 according to the present embodiment is a straight-six dual-fuel engine installed in large vessels. An operation mode of the dual-fuel engine can be switched as appropriate between a gas operation mode in which the engine operates with combustion gas burned, and a diesel operation mode in which the engine operates with fuel oil burned.
The engine 100 according to the present embodiment is not limited to the straight-six dual-fuel engine installed in large vessels. For example, the engine 100 may be an eight-cylinder engine or a diesel engine used for a land generator.
The engine 100 includes a cylinder block 10 and a cylinder head 20. The engine 100 further includes a compressed air starting device 40 and a cooling device 50.
In the cylinder block 10, a cylinder 11 and a combustion chamber 12 are formed. A piston 13 is slidably accommodated in the cylinder 11. The combustion chamber 12 is defined by the cylinder 11, a top portion of the piston 13, and the cylinder head 20.
The cylinder head 20 is provided with an intake port 21, a discharge port 22, an intake valve 23, a discharge valve 24, a fuel oil injection device 25, a gas ignition device 29, and a starter valve 60.
The intake port 21 is an inlet through which air enters the combustion chamber 12. The discharge port 22 is an outlet through which the air is discharged from the combustion chamber 12. The intake valve 23 is a valve for controlling opening/closing of the intake port 21. The discharge valve 24 is a valve for controlling opening/closing of the discharge port 22.
The intake port 21 is supplied with gas from an unillustrated gas supply device, and has an air-fuel ratio adjusted with an unillustrated throttle. Air taken in is mixed with the gas, and the resultant mixture is ignited by the gas ignition device 29.
The fuel oil injection device 25 is a valve with which combustion oil is injected into the combustion chamber 12 while the engine is in the diesel operation mode. The gas ignition device 29 is a device that injects fuel gas such as natural gas into the combustion chamber 12 while the engine is in the gas operation mode.
The starter valve 60 is a valve with which compressed air, sent from the compressed air starting device 40, is fed to the combustion chamber 12. The starter valve 60 is arranged in parallel with the axial direction of the cylinder 11, and is oriented toward the combustion chamber 12, in the cylinder head 20.
The compressed air starting device 40 starts the engine 100 with the compressed air. More specifically, the compressed air starting device 40 sends the compressed air to the combustion chamber 12 so that the piston 13 is pressed down with expansive power of the compressed air to rotate a crank shaft, whereby the engine 100 starts.
The compressed air starting device 40 includes the starter valve 60, an air container 41, and a distributing valve 42.
The air container 41 stores starting air under a predetermined pressure. The air container 41 includes: a valve box to which attachments are attached; and an air container main body. The attachments thus attached include an air container starter valve, air container charging valve, a drain valve, a safety valve, a pressure meter, and a lead plug (not illustrated).
The distributing valve 42 operates in such a manner that the compressed air is blown into the cylinder 11, upon being matched with a piston position of the cylinder 11. The distributing valve 42 includes a valve, a valve body, and a valve cover, and is driven by a cam shaft.
The cooling device 50 is a device that prevents overheating by the combustion, with cooling water flowing in a cooling water passage 26 formed around the combustion chamber 12, that is, in the cylinder block 10 and the cylinder head 20. The cooling device 50 includes a cooling water pump 51, a heat exchanger 52, the cooling water passage 26, a sea water passage 56, and a sea water pump 57.
The cooling water (fresh water in the present embodiment) circulates in the cooling water passage 26. The cooling water pump 51 sends water in a predetermined direction in the cooling water passage 26. The heat exchanger 52 is in charge of heat exchange between the cooling water in the cooling water passage 26 and the sea water in the sea water passage 56.
The sea water exchanges heat with the cooling water while flowing in the sea water passage 56. The sea water pump 57 sends water in a predetermined direction in the sea water passage 56.
A configuration of the starter valve 60 is described with reference to
In the cylinder head 20, the cooling water passage 26 described above, a starting air passage 27 as an air passage, a starter valve insertion hole 28, and a control air passage (not illustrated) are formed.
The starter valve insertion hole 28 is formed to be in parallel with the axial direction of the cylinder 11. The starter valve 60 fit in a sleeve 70, a supporting member 72, and a lid member 73 are disposed in the starter valve insertion hole 28.
The starting air passage 27 is formed to be orthogonal with the starter valve insertion hole 28. The starting air passage 27 has one side in communication with an intermediate portion of the starter valve insertion hole 28 that is an upper portion of the sleeve 70. The control air passage is formed to be in communication with a portion above a pilot valve 63 that is an intermediate portion of the supporting member 72.
As described above, the starter valve 60 is a valve with which the compressed air, sent from the compressed air starting device 40, is fed to the combustion chamber 12. The starter valve 60 is fit in the sleeve 70 and is arranged in parallel with the axis of the cylinder 11, in the cylinder head 20. The starter valve 60 includes a valve body 61, a casing 62, a pilot valve 63, and a return spring 64.
The casing 62 has a cylindrical shape, and has an intermediate portion on which a supply hole 62A is formed. The casing 62 incorporates the valve body 61, the return spring 64, and the pilot valve 63. The valve body 61 is biased upward by the return spring 64, and is contained in the casing 62 in such a manner as to be slidable in the axial direction.
The pilot valve 63 is a valve with which the valve body 61 is pressed downward by pressure of control air sent into the supporting member 72. The return spring 64 biases the valve body 61 upward with respect to the casing 62.
In the starter valve 60 with such a configuration, the starting air (compressed air), sent from the starting air passage 27, passes through the supply hole 62A of the casing 62 to be sent into the casing 62. Then, the pilot valve 63 presses the valve body 61 downward due to the pressure of the control air, and the compressed air in the casing 62 is sent into the combustion chamber 12.
The sleeve 70 in which the starter valve 60 is fit has a substantially cylindrical shape. More specifically, the sleeve 70 is inserted and fit in the starter valve insertion hole 28 with no gap in between.
The supporting member 72 has a substantially cylindrical shape, and is disposed between the starter valve 60 and the lid member 73 in the starter valve insertion hole 28. A supply hole 72A through which the control air, supplied through the control air passage, is sent into the supporting member 72, is formed on the supporting member 72.
The lid member 73 has a substantially column shape, and is disposed above the supporting member 72 in the starter valve insertion hole 28. More specifically, the lid member 73 is inserted and fit in the starter valve insertion hole 28 with no gap in between.
A configuration of the sleeve 70 is described with reference to
As described above, the sleeve 70 has the substantially cylindrical shape, and includes an outer circumferential surface 70A and a distal end surface 70B. A step portion 70C is formed on the outer circumferential surface 70A of the sleeve 70.
In a state where the starter valve 60 is fit in the sleeve 70 and the sleeve 70 in which the starter valve 60 is fit is fit in the starter valve insertion hole 28, the outer circumferential surface 70A of the sleeve 70 forms a part of the wall surface of the cooling water passage 26 formed around the sleeve 70.
In other words, the part of the wall surface of the cooling water passage 26 formed around the sleeve 70 is formed of the outer circumferential surface 70A of the sleeve 70.
In the state where the starter valve 60 is fit in the sleeve 70 and the sleeve 70 in which the starter valve 60 is fit is fit in the starter valve insertion hole 28, the distal end surface 70B of the sleeve 70 forms a part of the wall surface of the starting air passage 27. In other words, the part of the wall surface of the starting air passage 27 is formed of the distal end surface 70B of the sleeve 70.
In the state where the starter valve 60 is fit in the sleeve 70 and the sleeve 70 in which the starter valve 60 is fit is fit in the starter valve insertion hole 28, the step portion 70C of the sleeve 70 is engaged with a step portion 28C formed on the starter valve insertion hole 28.
Next, an effect of the engine 100 is described.
The engine 100 has an effect that the starter valve 60 can be disposed in a space saving manner.
Conventionally, the starter valve has been arranged in parallel with or orthogonal to the axial direction of the cylinder. Unfortunately, the configuration in which the starter valve is arranged orthogonal to the axial direction of the cylinder involves an extra space in the combustion chamber.
The configuration in which the starter valve is arranged in parallel with the axial direction of the cylinder requires a large thickness to separate the starter valve and the cooling water passage from each other. Thus, the starter valve requires a large space to be disposed in the cylinder head.
In the engine 100 according to the present embodiment, the starter valve 60 is arranged in parallel with the axial direction of the cylinder 11. The sleeve 70 in which the starter valve 60 is fit is inserted in the starter valve insertion hole 28, in such a manner that the outer circumferential surface 70A of the sleeve 70 forms a part of the wall surface of the cooling water passage 26 formed around the sleeve 70. Thus, the starter valve can be disposed in a space saving manner.
A dual-fuel engine requires the cylinder head 20 to be downsized so that the gas device and the diesel device can be disposed in the cylinder head 20. In view of this, the engine 100 according to the present embodiment can be downsized with the starter valve 60 disposed in a space saving manner.
For example, the configuration in which the starter valve 60 is fit in the sleeve 70 requires operations of forming a hole at a position of the sleeve 70 corresponding to the starting air passage 27 and positioning the hole thus formed with at the position corresponding to the starting air passage 27 when the sleeve 70 is inserted in the starter valve insertion hole 28 in an assembly operation.
In the engine 100 according to the present embodiment, the starter valve 60 is inserted in the sleeve 70 in such a manner that the distal end surface 70B of the sleeve 70 forms a part of the wall surface of the starting air passage 27. Thus, the sleeve 70 needs not to be positioned with respect to the starter valve insertion hole 28 in a circumference direction when the starter valve insertion hole 28 is inserted in the sleeve 70. Thus, a higher efficiency of the assembly operation can be achieved.
In the engine 100 according to the present embodiment, the step portion 70C of the sleeve 70 is engaged with the step portion 28C formed on the starter valve insertion hole 28, when the sleeve 70 is inserted in the starter valve insertion hole 28 during the assembly operation. Thus, the sleeve 70 needs not to be positioned with respect to the starter valve insertion hole 28 in the axial direction. Thus, a higher efficiency of the assembly operation can be achieved.
The present invention can be applied to an engine.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-265623 | Dec 2014 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/083957 | 12/3/2015 | WO | 00 |
