JP2019183724A - Variable compression device and engine system - Google Patents

Abstract

To inhibit collision energy from being applied through a piston rod to a restriction member.SOLUTION: The variable compression device having a fluid chamber forming member forming part of a fluid chamber into which pressurized working fluid is supplied to move the piston rod in the direction of increasing a compression ratio, and the restriction member for restricting the movement of the piston rod in the direction of increasing the compression ratio, includes an absorption member fixed to the restriction member or the piston rod for absorbing collision energy between the restriction member and the piston rod with the elastic deformation.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a variable compression device and an engine system.

  For example, Patent Document 1 discloses a large reciprocating piston combustion engine having a crosshead. The large reciprocating piston combustion engine of Patent Document 1 is a dual fuel engine that can be operated with both a liquid fuel such as heavy oil and a gaseous fuel such as natural gas. The large reciprocating piston combustion engine disclosed in Patent Document 1 changes both the compression ratio suitable for operation with liquid fuel and the compression ratio suitable for operation with gaseous fuel, so that the compression ratio is changed by moving the piston rod by hydraulic pressure. An adjustment mechanism is provided in the crosshead portion.

JP 2014-20375 A

  In the compression adjusting device that changes the compression ratio as described above, a regulating member that regulates the movement of the piston rod in the direction of increasing the compression ratio may be provided. When operating at a high compression ratio, the piston rod comes into contact with the regulating member. However, for example, when the piston rod is moved in a state where combustion pressure is not generated in the combustion chamber, such as when the engine is started, the piston rod collides with the regulating member, so that a large force is applied to the regulating member. There is a possibility of joining.

  The present invention has been made in view of the above-described problems, and an object thereof is to suppress collision energy applied from a piston rod to a regulating member.

  As a first means for solving the above-described problems, the present invention provides a fluid chamber that forms part of a fluid chamber in which a piston rod is moved in a direction to increase the compression ratio by supplying a pressurized working fluid. A variable compression device having a forming member and a restricting member that restricts movement of the piston rod in a direction in which the compression ratio is increased, and is fixed to the restricting member or the piston rod. The structure of having an absorbing member that absorbs collision energy by elastic deformation is adopted.

  As a second means, in the first means, there is a bolt for fixing the regulating member to the fluid chamber forming member, and the absorbing member is interposed between the regulating member and the head of the bolt. The structure of being provided is adopted.

  As a third means, in the second means, a configuration is adopted in which the absorbing member is provided between the regulating member and the piston rod.

  As a fourth means, in the first means, the restricting member has a recess into which the absorbing member is fitted.

  As a fifth means, the engine system employs a configuration including the variable compression device described in the first to fourth means.

  According to the present invention, it is possible to absorb the collision energy when the piston rod collides with the restricting member by elastically deforming the absorbing member. Therefore, the collision energy received by the restricting member from the piston rod can be reduced, and the impact on the restricting member can be reduced.

It is sectional drawing of the engine system in one Embodiment of this invention. 1 is a schematic cross-sectional view showing a part of an engine system in an embodiment of the present invention. It is a schematic cross section which shows the modification of the engine system in one Embodiment of this invention.

  Hereinafter, an embodiment of a variable compression device according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

[First Embodiment]
The engine system 100 of this embodiment is mounted on a ship such as a large tanker, for example, and includes an engine 1, a supercharger 200, and a control unit 300 (control means) as shown in FIG. In the present embodiment, the supercharger 200 is regarded as an auxiliary machine and will be described as a separate body from the engine 1 (main machine). However, the supercharger 200 can be configured as a part of the engine 1.

  The engine 1 is a multi-cylinder uniflow scavenging diesel engine, and has a gas operation mode in which gaseous fuel such as natural gas is burned together with liquid fuel such as heavy oil, and a diesel operation mode in which liquid fuel such as heavy oil is burned. Yes. In the gas operation mode, only gaseous fuel may be burned. Such an engine 1 includes a frame 2, a cylinder part 3, a piston 4, an exhaust valve unit 5, a piston rod 6, a crosshead 7, a hydraulic part 8, a connecting rod 9, and a crank angle sensor 10. A crankshaft 11, a scavenging reservoir 12, an exhaust reservoir 13, and an air cooler 14. The cylinder portion 3, the piston 4, the exhaust valve unit 5 and the piston rod 6 constitute a cylinder.

  The frame 2 is a strength member that supports the entire engine 1, and houses the crosshead 7, the hydraulic unit 8, and the connecting rod 9. Further, in the frame 2, a crosshead pin 7 a (to be described later) of the crosshead 7 can be reciprocated inside.

  The cylinder part 3 has a cylindrical cylinder liner 3a, a cylinder head 3b, and a cylinder jacket 3c. The cylinder liner 3a is a cylindrical member, and a sliding surface with the piston 4 is formed inside. A space surrounded by the inner peripheral surface of the cylinder liner 3a and the piston 4 is defined as a combustion chamber R1. A plurality of scavenging ports S are formed in the lower part of the cylinder liner 3a. The scavenging port S is an opening arranged along the peripheral surface of the cylinder liner 3a, and communicates the scavenging chamber R2 inside the cylinder jacket 3c with the inside of the cylinder liner 3a. The cylinder head 3b is a lid member provided at the upper end of the cylinder liner 3a. The cylinder head 3 b has an exhaust port H formed at the center in plan view and is connected to the exhaust reservoir 13. The cylinder head 3b is provided with a fuel injection valve (not shown). Further, an in-cylinder pressure sensor (not shown) is provided in the vicinity of the fuel injection valve of the cylinder head 3b. The in-cylinder pressure sensor detects the pressure in the combustion chamber R <b> 1 and transmits it to the control unit 300. The cylinder jacket 3c is a box-like member that is provided between the frame 2 and the cylinder liner 3a, and into which the lower end portion of the cylinder liner 3a is inserted. The scavenging chamber R2 of the cylinder jacket 3c is connected to the scavenging reservoir 12.

  The piston 4 has a substantially cylindrical shape, and is connected to a piston rod 6 described later and is disposed inside the cylinder liner 3a. A piston ring (not shown) is provided on the outer peripheral surface of the piston 4, and the piston ring seals the gap between the piston 4 and the cylinder liner 3a. The piston 4 slides in the cylinder liner 3a with the piston rod 6 due to pressure fluctuations in the combustion chamber R1.

  The exhaust valve unit 5 includes an exhaust valve 5a, an exhaust valve housing 5b, and an exhaust valve drive unit 5c. The exhaust valve 5a is provided inside the cylinder head 3b, and closes the exhaust port H in the cylinder part 3 by the exhaust valve drive part 5c. The exhaust valve housing 5b is a cylindrical housing that houses the end of the exhaust valve 5a. The exhaust valve drive unit 5 c is an actuator that moves the exhaust valve 5 a in a direction along the stroke direction of the piston 4.

  The piston rod 6 is a long member having one end connected to the piston 4 and the other end connected to the crosshead pin 7a. The end of the piston rod 6 is inserted into the cross head pin 7a and connected so that the connecting rod 9 can rotate. Further, the piston rod 6 has a large diameter portion in which a diameter of a part of the end portion on the cross head pin 7a side is thick.

  As shown in FIG. 2, the cross head 7 includes a cross head pin 7a (fluid chamber forming member), a guide shoe 7b, a lid member 7c (regulating member), a plurality of fixing bolts 7d, and a coil spring 7e (absorbing member). ). The cross head pin 7a is a columnar member that connects the piston rod 6 and the connecting rod 9 so as to be movable. A hydraulic chamber R3 (fluid chamber) in which hydraulic oil (working fluid) is supplied and discharged is formed by the insertion space into which the end of the piston rod 6 in the crosshead pin 7a is inserted and the flange of the piston rod 6. . In the cross head pin 7a, an outlet hole O penetrating along the axial direction of the cross head pin 7a is formed below the center. The outlet hole O is an opening through which cooling oil that has passed through a cooling flow path (not shown) of the piston rod 6 is discharged. The crosshead pin 7a is provided with a supply flow path R4 that connects the hydraulic chamber R3 and a plunger pump 8c, which will be described later, and a relief flow path R5, which connects the hydraulic chamber R3 and a relief valve 8f, which will be described later. Yes.

  The guide shoe 7b is a member that supports the cross head pin 7a, and moves on a guide rail (not shown) along the stroke direction of the piston 4 along with the cross head pin 7a. When the guide shoe 7b moves along the guide rail, the cross head pin 7a is restricted from moving in directions other than the linear direction along the stroke direction of the piston 4. The lid member 7c is an annular member that is fixed to the upper part of the cross head pin 7a and into which the end of the piston rod 6 is inserted.

  The fixing bolt 7d has a head portion 7d1 and a shaft portion 7d2. The shaft portion 7d2 is inserted into a bolt hole provided in the lid member 7c, and fixes the lid member 7c to the cross head pin 7a. The fixing bolt 7d has a head 7d1 separated from the lid member 7c, and a coil spring 7e (absorbing member) is inserted between the head 7d1 and the lid member 7c. The coil spring 7e is fixed to the surface (upper surface) of the lid member 7c that does not contact the cross head pin 7a by the head 7d1 of the fixing bolt 7d, and the lid member 7c faces the cross head pin 7a (downward). Energized. Such a crosshead 7 transmits the linear motion of the piston 4 to the connecting rod 9.

  As shown in FIG. 2, the hydraulic section 8 includes a supply pump 8a, a swing pipe 8b, a plunger pump 8c, a first check valve 8d and a second check valve 8e included in the plunger pump 8c, and a relief valve. 8f. Further, the piston rod 6, the cross head 7, the hydraulic unit 8, and the control unit 300 function as a variable compression device in the present invention.

  The supply pump 8a is a pump that boosts the hydraulic oil supplied from a hydraulic oil tank (not shown) based on an instruction from the control unit 300 and supplies the pressure to the plunger pump 8c. The supply pump 8a is driven by the power of the generator of the ship and can operate before liquid fuel is supplied to the combustion chamber R1. The swing pipe 8b is a pipe that connects the supply pump 8a and the plunger pump 8c of each cylinder, and swings between the plunger pump 8c that moves with the crosshead pin 7a and the fixed supply pump 8a. It is possible.

  The plunger pump 8c is fixed to the cross head pin 7a, and includes a rod-shaped plunger 8c1, a cylindrical cylinder 8c2 that slidably accommodates the plunger 8c1, and a plunger drive unit 8c3. The plunger pump 8c slides in the cylinder 8c2 when the plunger 8c1 is connected to a drive unit (not shown), boosts the operating oil, and supplies it to the hydraulic chamber R3. Further, the cylinder 8c2 is provided with a first check valve 8d at an opening on the discharge side of hydraulic oil provided at an end portion, and a second check valve 8e is provided at an intake side opening provided on the side peripheral surface. Is provided. The plunger drive unit 8c3 is connected to the plunger 8c1 and reciprocates the plunger 8c1 based on an instruction from the control unit 300.

  The first check valve 8d is configured to close by energizing the valve body toward the inside of the cylinder 8c2, and prevents hydraulic oil supplied to the hydraulic chamber R3 from flowing back to the cylinder 8c2. is doing. Further, the first check valve 8d causes the valve body to be pushed by the hydraulic oil when the pressure of the hydraulic oil in the cylinder 8c2 becomes equal to or greater than the biasing force (opening pressure) of the biasing member of the first check valve 8d. To open the valve. The second check valve 8e is urged toward the outside of the cylinder 8c2, and prevents the hydraulic oil supplied to the cylinder 8c2 from flowing back to the supply pump 8a. The second check valve 8e is configured such that when the pressure of the hydraulic oil supplied from the supply pump 8a becomes equal to or greater than the biasing force (opening pressure) of the biasing member of the second check valve 8e, Opens when pressed. The first check valve 8d has a valve opening pressure higher than the valve opening pressure of the second check valve 8e, and is supplied from the supply pump 8a during steady operation that is operated at a preset compression ratio. The valve will not open due to the pressure of hydraulic oil.

  The relief valve 8f is provided on the cross head pin 7a, and has a main body portion 8f1 and a relief valve drive portion 8f2. The main body 8f1 is a valve connected to the hydraulic chamber R3 and a hydraulic oil tank (not shown). The relief valve drive unit 8f2 is connected to the valve body of the main body unit 8f1, and opens and closes the main body unit 8f1 based on an instruction from the control unit 300. When the relief valve 8f is opened by the relief valve drive unit 8f2, the hydraulic oil stored in the hydraulic chamber R3 is returned to the hydraulic oil tank.

  As shown in FIG. 1, the connecting rod 9 is a long member that is connected to the crosshead pin 7 a and connected to the crankshaft 11. The connecting rod 9 converts the linear motion of the piston 4 transmitted to the cross head pin 7a into rotational motion. The crank angle sensor 10 is a sensor for measuring the crank angle of the crankshaft 11, and transmits a crank pulse signal for calculating the crank angle to the control unit 300.

  The crankshaft 11 is a long member connected to a connecting rod 9 provided in the cylinder, and transmits power to, for example, a screw or the like by being rotated by a rotational motion transmitted by each connecting rod 9. The scavenging reservoir 12 is provided between the cylinder jacket 3c and the supercharger 200, and air pressurized by the supercharger 200 flows in. The scavenging reservoir 12 is provided with an air cooler 14 therein. The exhaust reservoir 13 is a tubular member that is connected to the exhaust port H of each cylinder and to the supercharger 200. The gas discharged from the exhaust port H is temporarily stored in the exhaust reservoir 13 and supplied to the supercharger 200 with pulsation suppressed. The air cooler 14 is a device that cools the air inside the scavenging reservoir 12.

  The supercharger 200 is a device that pressurizes air sucked from the outside of the engine by a driven blower (not shown) by a turbine rotated by gas discharged from the exhaust port H and supplies the pressurized air to the early reservoir 12.

  The control unit 300 is a computer that controls a fuel supply amount and the like based on an operation by a ship operator. Further, the control unit 300 controls the hydraulic unit 8 to change the compression ratio in the combustion chamber R1. Specifically, the control unit 300 acquires position information of the piston rod 6 based on a signal from the in-cylinder pressure sensor, controls the plunger pump 8c, the supply pump 8a, and the relief valve 8f, and operates the hydraulic oil in the hydraulic chamber R3. By adjusting the amount, the position of the piston rod 6 is changed to change the compression ratio. Furthermore, the control unit 300 changes the amount of lubrication and the timing of lubrication of the lubrication device 15 based on the position information of the piston rod 6.

  Such an engine system 100 is a device that rotates the crankshaft 11 by causing the piston 4 to slide in the cylinder liner 3a by igniting and exploding fuel injected into the combustion chamber R1 from a fuel injection valve (not shown). is there. More specifically, the gaseous fuel supplied to the combustion chamber R1 is mixed with the air flowing in from the scavenging port S, and then compressed as the piston 4 moves toward the top dead center, and the temperature rises. At this time, it burns by injecting a small amount of liquid fuel as an ignition source. Moreover, in the case of liquid fuel, it burns by being injected into the compressed air in the combustion chamber R1.

  Then, the fuel in the combustion chamber R <b> 1 burns and expands rapidly, and the piston 4 is pressurized toward the bottom dead center. As a result, the piston 4 moves in the direction of the bottom dead center, the piston rod 6 is moved along with the piston 4, and the crankshaft 11 is rotated via the connecting rod 9. Furthermore, when the piston 4 is moved to the bottom dead center, the pressurized air flows from the scavenging port S into the combustion chamber R1. When the exhaust valve unit 5 is driven, the exhaust port H is opened, and the exhaust gas in the combustion chamber R1 is pushed out to the exhaust reservoir 13 by the pressurized air.

  When increasing the compression ratio, the supply pump 8a is driven by the controller 300, and hydraulic oil is supplied to the plunger pump 8c. And the control part 300 drives the plunger pump 8c, pressurizes hydraulic oil until it becomes the pressure which can lift the piston rod 6, and supplies hydraulic oil to hydraulic chamber R3. Due to the pressure of the hydraulic oil in the hydraulic chamber R3, the end of the piston rod 6 is lifted, and accordingly, the top dead center position of the piston 4 is moved upward (exhaust port H side).

  In order to reduce the compression ratio, the relief valve 8f is driven by the controller 300, and the hydraulic chamber R3 and a hydraulic oil tank (not shown) are in communication with each other. Then, the load of the piston rod 6 is applied to the hydraulic oil in the hydraulic chamber R3, and the hydraulic oil in the hydraulic chamber R3 is pushed out to the hydraulic oil tank via the relief valve 8f. As a result, the hydraulic oil in the hydraulic chamber R3 is reduced, the piston rod 6 is moved downward (crankshaft 11 side), and the top dead center position of the piston 4 is moved downward accordingly.

  When the piston rod 6 is moved in the high compression ratio direction, the piston rod 6 contacts the lid member 7c. At this time, the lid member 7c slightly lifts from the cross head pin 7a, but returns to the cross head pin 7a by the biasing force of the coil spring 7e. Thereby, the collision energy received from the piston rod 6 is absorbed by the coil spring 7e, and it can prevent that big force is added to the cover member 7c.

  Moreover, in this embodiment, since the piston rod 6 and the coil spring 7e do not contact | abut, when the piston rod 6 is moved to a high compression ratio direction, the movement of the piston rod 6 is prevented by the coil spring 7e. There is no.

[Second Embodiment]
Next, a modification of the first embodiment will be described as a second embodiment with reference to FIG. Note that the same constituent members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the engine 1 according to the present embodiment, the coil spring 7e is not inserted into the fixing bolt 7d, and a plurality of recesses 7c1 are provided at equal intervals on the surface (lower surface) that contacts the flange of the piston rod 6 of the lid member 7c. The coil spring 7e is fitted. That is, the coil spring 7e is provided between the flange of the piston rod 6 and the lid member 7c. Note that the lid member 7c and the flange do not come into contact with each other when the coil spring 7e is completely compressed.

  According to this embodiment, when the piston rod 6 is moved in the high compression ratio direction, the piston rod 6 contacts the coil spring 7e before contacting the lid member 7c, and the coil When the spring 7e is elastically deformed, the collision energy is absorbed and the moving speed is reduced. Thereby, it can prevent that the piston rod 6 collides violently with respect to the cover member 7c.

  Furthermore, in this embodiment, since the piston rod 6 contacts the coil spring 7e before contacting the lid member 7c, the impact on the lid member 7c can be more effectively prevented.

  Moreover, in this embodiment, the recessed part 7c1 is formed in the position in which the coil spring 7e in the cover member 7c is installed, and the coil spring 7e is fitted and fixed to the recessed part 7c1. As a result, the coil spring 7e does not deviate from the predetermined position, and the coil spring 7e and the piston rod 6 always come into contact with each other at a constant position, so that the collision energy can be effectively absorbed.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the present invention.

  In the said embodiment, although the coil spring 7e was provided as an absorption member, this invention is not limited to this. For example, rubber or the like may be provided instead of the coil spring 7e as the absorbing member.

  In the first embodiment, the coil spring 7e is disposed between the head of the fixing bolt 7d and the lid member 7c, but the present invention is not limited to this. The coil spring 7e may be provided between a spring fixing member provided separately from the fixing bolt 7d and the lid member 7c.

  In addition, the coil spring 7e may be provided on the surface of the flange of the piston rod 6 that contacts the lid member 7c, instead of being provided on the lid member 7c.

  In the above embodiment, the coil spring 7e is fitted or fixed directly to the lid member 7c by the fixing bolt 7d, but the present invention is not limited to this. The coil spring 7e may be fixed to the lid member 7c or the piston rod 6 indirectly through another member such as a washer, for example.

DESCRIPTION OF SYMBOLS 1 Engine 2 Frame 3 Cylinder part 3a Cylinder liner 3b Cylinder head 3c Cylinder jacket 4 Piston 5 Exhaust valve unit 5a Exhaust valve housing 5c Exhaust valve drive part 6 Piston rod 7 Crosshead 7a Crosshead pin 7b Guide shoe 7c Cover member 7d Fixing bolt 7e Coil spring 8 Hydraulic part 8a Supply pump 8b Oscillating pipe 8c Plunger pump 8c1 Plunger 8c2 Cylinder 8c3 Plunger drive part 8d First check valve 8e Second check valve 8f Relief valve 8f1 Main part 8f2 Relief valve drive part 8g Booster pump 9 Connecting rod 10 Crank angle sensor 11 Crankshaft 12 Scavenging reservoir 13 Exhaust reservoir 14 Air cooler 100 Engine system 200 Supercharger 300 Control unit H Exhaust port S Scavenging port O Exit hole R1 Combustion chamber R2 Scavenging chamber R3 Hydraulic pressure Chamber R4 Supply channel R5 Relief channel

Claims (5)

A fluid chamber forming member that forms part of the fluid chamber in which the piston rod is moved in a direction to increase the compression ratio by supplying the pressurized working fluid, and a movement in the direction to increase the compression ratio of the piston rod. A variable compression device having a regulating member for regulating,
A variable compression device comprising an absorbing member fixed to the restricting member or the piston rod and absorbing collision energy between the restricting member and the piston rod by elastic deformation. A bolt for fixing the regulating member to the fluid chamber forming member;
The variable compression apparatus according to claim 1, wherein the absorbing member is provided between the restricting member and a head of the bolt.   The variable compression device according to claim 1, wherein the absorbing member is provided between the regulating member and the piston rod.   The variable compression device according to claim 3, wherein the restricting member has a recess into which the absorbing member is fitted.   An engine system comprising the variable compression device according to any one of claims 1 to 4.

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