JP6904130B2 - Variable compressor and engine system - Google Patents

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 capable of operating on both a liquid fuel such as heavy oil and a gaseous fuel such as natural gas. The large reciprocating piston combustion engine of Patent Document 1 has an adjustment mechanism in the crosshead portion that allows the compression ratio to be changed in order to support both a compression ratio suitable for operation with liquid fuel and a compression ratio suitable for operation with gas fuel. It is provided.

Japanese Unexamined Patent Publication No. 2014-20375

In the engine adjustment mechanism as described above, unlike the piston combustion engine having a constant compression ratio, the piston rod is movable with respect to the crosshead, so that the piston rod is not fixed to the crosshead pin. Therefore, the piston rod may rotate with respect to the crosshead pin. The rotation of the piston rod may cause the piston to rotate, changing the sliding characteristics of the piston with respect to the cylinder liner.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to regulate the movement of the piston in the rotational direction.

The present invention has a variable chamber having a fluid chamber in which the piston rod is moved in a direction of increasing the compression ratio by supplying a boosted working fluid as a first means for a variable compression device for solving the above problems. The compression device is provided with a regulating member that regulates the movement of the piston rod in the rotational direction.

As a second means relating to the variable compression device, in the first means, the regulating member adopts a configuration in which the regulating member has a regulating pin inserted into the opening of the piston rod from below the piston rod.

As a third means relating to the variable compression device, in the first means, the regulating member has a regulating pin inserted into the opening of the piston rod.

As the first means relating to the engine system, a configuration is adopted in which a variable compression device of any of the above-mentioned first to third means is provided.

According to the present invention, the restricting member regulates the movement of the piston rod in the rotational direction, and accordingly, the movement of the piston connected to the piston rod in the rotational direction is restricted. This makes it possible to prevent the sliding characteristics of the piston with respect to the cylinder liner from changing.

It is sectional drawing of the engine system in one Embodiment of this invention. It is a partial cross-sectional view of the engine system in one Embodiment of this invention. It is an enlarged sectional view of a part of the variable compression apparatus in one Embodiment of this invention. It is a partial cross-sectional view which shows the modification of the variable compression apparatus in one Embodiment of this invention. It is a partial cross-sectional view which shows the modification of the variable compression apparatus in one Embodiment of this invention.

Hereinafter, an embodiment of the engine system 100 according to the present invention will be described with reference to the drawings. In the drawings below, the scale of each member is appropriately changed in order to make each member recognizable.

The engine system 100 of the present embodiment is mounted on a ship such as a large tanker, and includes an engine 1, a supercharger 200, and a control unit 300 as shown in FIG. In the present embodiment, the supercharger 200 will be regarded as an auxiliary machine, and will be described as a separate body from the engine 1 (main engine). However, it is also possible to configure the turbocharger 200 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 a gas fuel such as natural gas is burned together with a liquid fuel such as heavy oil, and a diesel operation mode in which the liquid fuel such as heavy oil is burned. There is. In the gas operation mode, only the gas fuel may be burned. As shown in FIGS. 1 and 2, such an engine 1 includes a frame 2, a cylinder portion 3, a piston 4, an exhaust valve unit 5, a piston rod 6, a crosshead 7, and a hydraulic portion 8. A connecting rod 9, a crank angle sensor 10, a crankshaft 11, a scavenging reservoir 12, an exhaust reservoir 13, and an air cooler 14 are provided. Further, the cylinder is composed of the cylinder portion 3, the piston 4, the exhaust valve unit 5, and the piston rod 6.

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

The cylinder portion 3 includes a cylindrical cylinder cover 3a, a cylinder liner 3b, a cylinder head 3c, and a cylinder jacket 3d. The cylinder liner 3b is a cylindrical member housed in the cylinder cover 3a, and a sliding surface with the piston 4 is formed inside. The space surrounded by the inner peripheral surface of the cylinder liner 3b and the piston 4 is defined as the combustion chamber R1. Further, a plurality of scavenging ports S are formed in the lower part of the cylinder liner 3b. The scavenging port S is an opening arranged along the peripheral surface of the cylinder liner 3b, and communicates the scavenging chamber R2 inside the cylinder jacket 3d with the inside of the cylinder liner 3b. The cylinder head 3c is a lid member provided at the upper end of the cylinder cover 3a. The cylinder head 3c is connected to the exhaust reservoir 13 by forming an exhaust port H at the center in a plan view. Further, the cylinder head 3c is provided with a fuel injection valve (not shown). The cylinder jacket 3d is a cylindrical member provided between the frame 2 and the cylinder cover 3a and into which the lower end of the cylinder liner 3b is inserted, and a scavenging chamber R2 is formed therein. Further, the scavenging chamber R2 of the cylinder jacket 3d is connected to the scavenging reservoir 12.

The piston 4 has a substantially cylindrical shape, is connected to a piston rod 6 described later, and is arranged inside the cylinder liner 3b. Further, a piston ring (not shown) is provided on the outer peripheral surface of the piston 4, and the gap between the piston 4 and the cylinder liner 3b is sealed by the piston ring. The piston 4 slides in the cylinder liner 3b together with the piston rod 6 due to the fluctuation of the pressure 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 3c, and the exhaust valve driving portion 5c closes the exhaust port H in the cylinder portion 3. The exhaust valve housing 5b is a cylindrical housing that accommodates an end portion of the exhaust valve 5a. The exhaust valve drive unit 5c is an actuator that moves the exhaust valve 5a in the 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 crosshead pin 7a and is connected so that the connecting rod 9 can rotate. Further, as shown in FIG. 3A, the piston rod 6 is formed on the outer peripheral surface of the piston rod 6 by intermittently forming a plurality of protrusions on the outer peripheral surface at a portion arranged inside the lid member 7c described later. Unevenness is formed. The unevenness of the piston rod 6 functions as serrations.

The crosshead 7 includes a crosshead pin 7a, a guide shoe 7b, and a lid member 7c. The cross head pin 7a is a columnar member that movably connects the piston rod 6 and the connecting rod 9, and supplies and discharges hydraulic oil (working fluid) to the insertion space into which the end of the piston rod 6 is inserted. The hydraulic chamber R3 (fluid chamber) to be performed is formed. The cross head pin 7a is formed with an outlet hole O that penetrates along the axial direction of the cross head pin 7a below the center. The outlet hole O is an opening through which the cooling oil that has passed through the cooling flow path (not shown) of the piston rod 6 is discharged. Internally, the crosshead pin 7a is provided with a supply flow path R4 for connecting the hydraulic chamber R3 and the plunger pump 8c described later, and a relief flow path R5 for connecting the hydraulic chamber R3 and the relief valve 8f described later. There is. Further, the crosshead 7 is formed with an auxiliary flow path R6 in which the crosshead pin 7a and the lid member 7c are communicated with each other and opened on the peripheral surface of the piston rod 6 and the peripheral surface of the crosshead pin 7a.

The guide shoe 7b is a member that rotatably supports the cross head pin 7a, and moves along the stroke direction of the piston 4 on a guide rail (not shown) 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 rotating and moving in a direction other than the linear direction along the stroke direction of the piston 4. The lid member 7c is an annular member fixed to the upper portion of the cross head pin 7a and into which the end portion of the piston rod 6 is inserted. Further, the lid member 7c is formed with a recess corresponding to a protrusion on the outer periphery of the piston rod 6 on the inner peripheral surface of the through hole into which the piston rod 6 is inserted. When the protrusion of the piston rod 6 and the recess of the lid member 7c mesh with each other, the lid member 7c functions as a regulating member that regulates the rotation of the piston rod 6. Such a crosshead 7 transmits the linear motion of the piston 4 to the connecting rod 9.

As shown in FIG. 2, the hydraulic unit 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. It has 8f. Further, the piston rod 6, the crosshead 7, the hydraulic unit 8, and the control unit 300 function as the variable compression device in the present invention. Further, the supply pump 8a, the swing pipe 8b, the plunger pump 8c, the first check valve 8d and the second check valve 8e correspond to the boosted fluid supply unit in the present invention.

The supply pump 8a is a pump that boosts the hydraulic oil supplied from the hydraulic oil tank (not shown) and supplies it to the plunger pump 8c based on the instruction from the control unit 300. The supply pump 8a is driven by the electric power of the battery of the ship and can be operated before the 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 along with the crosshead pin 7a and the fixed supply pump 8a. It is possible.

The plunger pump 8c is fixed to a cross head pin 7a, and includes a rod-shaped plunger 8c1, a tubular cylinder 8c2 that slidably accommodates the plunger 8c1, and a plunger drive unit 8c3. When the plunger 8c1 is connected to a drive unit (not shown), the plunger pump 8c slides in the cylinder 8c2 to boost the hydraulic oil and supply it to the hydraulic chamber R3. Further, the cylinder 8c2 is provided with a first check valve 8d at the opening on the discharge side of the hydraulic oil provided at the end, and a second check valve 8e is provided at the opening on the suction side provided on the side peripheral surface. It 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 has a structure in which the valve body is urged toward the inside of the cylinder 8c2 to close the valve, and prevents the hydraulic oil supplied to the hydraulic chamber R3 from flowing back into the cylinder 8c2. doing. Further, in the first check valve 8d, the valve body is pushed by the hydraulic oil when the pressure of the hydraulic oil in the cylinder 8c2 becomes equal to or higher than the urging force (valve opening pressure) of the urging 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 to prevent the hydraulic oil supplied to the cylinder 8c2 from flowing back to the supply pump 8a. Further, in the second check valve 8e, when the pressure of the hydraulic oil supplied from the supply pump 8a becomes equal to or higher than the urging force (valve opening pressure) of the urging member of the second check valve 8e, the valve body becomes the hydraulic oil. The valve is opened by being pushed. The first check valve 8d is supplied from the supply pump 8a during steady operation in which the valve opening pressure is higher than the valve opening pressure of the second check valve 8e and is operated at a preset compression ratio. The valve does not open due to the pressure of the hydraulic oil.

The relief valve 8f is provided on the cross head pin 7a, and includes a main body portion 8f1 and a relief valve driving 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 8f1 and opens and closes the main body 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 cross head pin 7a and also to the crankshaft 11. The connecting rod 9 converts the linear motion of the piston 4 transmitted to the crosshead pin 7a into a rotary 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 a cylinder, and is rotated by a rotational motion transmitted by each connecting rod 9, thereby transmitting power to, for example, a screw or the like. The scavenging reservoir 12 is provided between the cylinder jacket 3d and the supercharger 200, and the air pressurized by the supercharger 200 flows into the scavenging reservoir 12. Further, the scavenging reservoir 12 is provided with an air cooler 14 inside. The exhaust reservoir 13 is a tubular member connected to the exhaust port H of each cylinder and connected to the supercharger 200. The gas discharged from the exhaust port H is temporarily stored in the exhaust reservoir 13 and is supplied to the supercharger 200 in a state where pulsation is 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 the air sucked from the intake port (not shown) by a turbine rotated by the gas discharged from the exhaust port H and supplies the air to the combustion chamber R1.

The control unit 300 is a computer that controls the fuel supply amount and the like based on the operation and the like by the operator of the ship. Further, the control unit 300 changes the compression ratio in the combustion chamber R1 by controlling the hydraulic unit 8. Specifically, the control unit 300 controls the plunger pump 8c, the supply pump 8a, and the relief valve 8f, and adjusts the amount of hydraulic oil in the hydraulic chamber R3 to change the position of the piston rod 6 and reduce the compression ratio. To change.

Such an engine system 100 is a device that ignites and explodes the fuel injected into the combustion chamber R1 from a fuel injection valve (not shown) to slide the piston 4 in the cylinder liner 3b and rotate the crankshaft 11. is there. More specifically, the fuel supplied to the combustion chamber R1 is mixed with the air flowing in from the scavenging port S, and then compressed by the piston 4 moving toward the top dead center, and the temperature rises naturally. Ignite. Further, in the case of liquid fuel, the temperature rises in the combustion chamber R1 to vaporize and spontaneously ignite.

Then, the fuel in the combustion chamber R1 spontaneously ignites and rapidly expands, and pressure is applied to the piston 4 toward the bottom dead center. As a result, the piston 4 moves toward 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. Further, when the piston 4 is moved to the bottom dead center, pressurized air flows into the combustion chamber R1 from the scavenging port S. 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 the compression ratio is increased, the supply pump 8a is driven by the control unit 300, and hydraulic oil is supplied to the plunger pump 8c. Then, the control unit 300 drives the plunger pump 8c to pressurize the hydraulic oil until the pressure is such that the piston rod 6 can be lifted, and supplies the hydraulic oil to the hydraulic chamber R3. The pressure of the hydraulic oil in the hydraulic chamber R3 lifts the end of the piston rod 6, and the top dead center position of the piston 4 is moved upward (exhaust port H side) accordingly.

When the compression ratio is reduced, the relief valve 8f is driven by the control unit 300, and the hydraulic chamber R3 and the 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.

According to such a variable compression device in the present embodiment, the movement of the piston rod 6 in the rotational direction is restricted by the engagement between the protrusion of the piston rod 6 and the recess of the lid member 7c, and accordingly. The movement of the piston 4 in the rotational direction is restricted. This makes it possible to prevent the sliding characteristics of the piston 4 from changing.

Further, according to the variable compression device in the present embodiment, the movement in the rotation direction is restricted by processing the piston rod 6 and the lid member 7c. Therefore, the influence of the regulation member on the hydraulic chamber R3 can be minimized, and the influence on the performance of the engine 1 is small.

Although the preferred embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited to the above embodiment. The various shapes and combinations of the constituent members shown in the above-described embodiment are examples, and can be variously changed based on design requirements and the like without departing from the spirit of the present invention.

The shape of the serrations of the piston rod 6 and the lid member 7c is not limited to the shape of FIG. 3A of the above embodiment. Serrations are provided at the lower end of the piston rod 6 (position below the hydraulic chamber R3) and the inner peripheral surface of the cross head pin 7a as long as the seal ring provided on the piston rod 6 does not interfere. You may. Further, for example, as shown in FIG. 3B, a large number of protrusions on the peripheral surface of the piston rod 6 may be provided at a fine pitch. Further, as shown in FIG. 3C, the protrusion of the piston rod 6 may have a shape with a sharp tip.
Further, the stuffing box for scraping off the waste oil of the lubricating oil on the surface of the piston rod 6 and the position where the piston rod 6 comes into contact with the stuffing box may be serrated.

Further, serrations are not formed in the piston rod 6 and the lid member 7c, and as shown in FIG. 4, an opening is formed in the upper surface portion of the large diameter portion of the piston rod 6, and the engine 1 sets the movement restricting portion 15 in place. It may be provided. The movement restricting portion 15 has a plurality of restricting pins 15a provided above the large diameter portion of the piston rod 6 at equal intervals in the circumferential direction, and the restricting pins 15a are inserted into the opening of the piston rod 6 to cause the piston rod. The movement of 6 in the rotation direction can be regulated. The regulation pin 15a is fixed to the lid member 7c by welding, tightening, or the like. Further, the regulation pin 15a may be provided on the outside of the large diameter portion of the piston rod 6.
Further, the movement restricting unit 15 may have a driving unit 15b. The drive unit 15b raises and lowers the regulation pin 15a based on the instruction from the control unit 300 as the piston rod 6 moves in the high compression ratio direction and the low compression ratio direction, and moves the regulation pin 15a to the piston rod 6. It can be inserted into the opening.

Further, as shown in FIG. 5, the movement restricting portion 15 may have a restricting pin 15c provided below the large diameter portion of the piston rod 6. In this case, an opening is formed in the upper surface of the large diameter portion of the piston rod 6, and the regulation pin 15c is inserted into the opening to restrict the movement of the piston rod 6 in the rotational direction. In this case as well, it is possible to provide the drive unit 15b in the same manner.

1 Engine 2 Frame 3 Cylinder part 3a Cylinder cover 3b Cylinder liner 3c Cylinder head 3d Cylinder jacket 4 Piston 5 Exhaust valve unit 5a Exhaust valve 5b Exhaust valve housing 5c Exhaust valve drive part 6 Piston rod 7 Cross head 7a Cross head pin 7b Guide shoe 7c Lid member 8 Hydraulic part 8a Supply pump 8b Swing pipe 8c Plunger pump 8c1 Plunger 8c2 Cylinder 8c3 Plunger drive part 8d 1st check valve 8e 2nd check valve 8f Relief valve 8f1 Main body part 8f2 Relief valve drive part 8g Booster pump 9 Connecting rod 10 Cylinder angle sensor 11 Crankshaft 12 Sweeping reservoir 13 Exhaust reservoir 14 Air cooler 15 Movement regulation unit 15a Regulation pin 15b Drive unit 15c Regulation pin 100 Engine system 200 Supercharger 300 Control unit H Exhaust port O Outlet hole R1 Combustion Chamber R2 Sweep chamber R3 Hydraulic chamber R4 Supply flow path R5 Relief flow path R6 Auxiliary flow path S Sweep port

Claims (2)

A variable compression device having a fluid chamber in which the piston rod is moved in a direction of increasing the compression ratio by supplying a boosted working fluid.
A regulating member that regulates the movement of the piston rod in the rotational direction is provided .
The regulating member is a variable compression device characterized in that the outer peripheral surface on the upper end side of the cross head pin has an uneven shape. An engine system including the variable compression device according to claim 1.

Images