JP2015187429A - Method of reduced-cylinder operation of electronically controlled two-cycle internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable reduced-cylinder operation of an internal combustion engine at a time of a low load by preventing the abrasion of a crosshead bearing portion and to thereby achieve great improvement in fuel economy.SOLUTION: Provided is a method of reduced-cylinder operation of an electronically controlled two-cycle internal combustion engine (1) including a crosshead (8) is provided. An electronic control unit (5) performs a reduced-cylinder operation for operating the internal combustion engine (1) without injecting a fuel to part of a plurality of cylinders depending on a load of the internal combustion engine (1), and reduces a gas pressure applied to a piston of an inactive cylinder (3) to which the fuel is not injected by actuating an exhaust valve actuation mechanism (20) during a reduced-cylinder operation to open an exhaust valve (21) of the inactive cylinder (3) in a crank angle range different from that of exhaust valves of active cylinders to which the fuel is injected.

Description

  The present invention relates to a reduced-cylinder operation method for an electronically controlled two-cycle internal combustion engine.

  In recent years, for example, in the operation of a ship equipped with a two-cycle internal combustion engine, it is common to perform low-load operation in order to reduce fuel consumption. However, in a two-cycle internal combustion engine equipped with a supercharger, the performance of the internal combustion engine itself is sufficiently exhibited because the supercharger performance is significantly reduced due to insufficient exhaust energy at low loads, resulting in a decrease in scavenging pressure due to insufficient intake air quantity. There is a problem that you can not.

  As a measure for preventing a decrease in scavenging pressure due to an insufficient intake amount during low load operation, a large turbocharger is installed, and a large turbocharger is operated when the load is low (for example, Patent Document 1). ) Exhaust bypass system that raises the scavenging pressure at low load by a large turbocharger and releases part of the exhaust gas sent to the supercharger to the atmosphere at high load to reduce the supercharging capability (for example, Patent Document 2) A scavenging bypass system (for example, Patent Document 3) that raises the scavenging pressure at low load by a large turbocharger and releases part of the scavenging air sent from the supercharger to the atmosphere at high load, for example, supercharging at low load There is a variable nozzle type turbocharger (for example, Patent Document 4) that increases the scavenging pressure by reducing the turbine nozzle area of the machine and increasing the exhaust energy, thereby increasing the scavenging pressure at low load. And improves fuel economy and performance improvement of the engine Te.

  However, when the internal combustion engine is under a low load, the indicated mean effective pressure in the cylinder is low, so the exhaust energy density is small, and only improving the supercharging by the supercharger improves the overall fuel consumption and performance of the internal combustion engine. It ’s difficult.

  On the other hand, as a general practice for internal combustion engines, there is a reduced-cylinder operation in which fuel injection in some cylinders is stopped in accordance with the engine load and the cylinders are operated without performing combustion ( For example, Patent Document 5).

  If, for example, a two-cycle internal combustion engine for a ship can be operated with reduced cylinders at a low load, a marked improvement in fuel consumption can be expected compared to the above-described supercharger countermeasure. Therefore, for example, a two-cycle internal combustion engine for ships is strongly desired to perform a reduced-cylinder operation.

JP 07-293262 A JP 05-33663 A JP 2010-23631 A JP-A-5-248254 JP 2014-15898 A

  However, for example, in a two-cycle internal combustion engine for ships, as shown in FIG. 10, a piston 101 that slides up and down in a cylinder, a piston rod 102 connected to the piston 101, and a crank chamber are arranged. The crosshead 103 connected to the piston rod 102 and reciprocating up and down in the crank chamber is connected to the crosshead 103 and the crankshaft 105 via the crosshead bearing 104 of the crosshead 103. The connecting rod 106 that works to convert a reciprocating motion into a rotational motion is employed.

  As shown in FIG. 11, conventionally, with respect to the reduced cylinder that does not perform combustion by stopping fuel injection, the exhaust valve 107 is opened within the same crank angle range as the working cylinder that performs fuel injection and combustion. Exhaust by a valve and scavenging introduction from a scavenging hole (not shown) are performed.

  Here, as shown in FIG. 11, the above-described conventional exhaust valve 107 is, for example, fully opened after the piston 101 passes the intermediate point of the downward stroke, and before the piston 101 reaches the intermediate point in the upward stroke. Fully closed. Therefore, as shown in FIG. 12, as the piston 101 rises toward the top dead center, the gas in the cylinder is compressed and the gas pressure is significantly increased.

  For this reason, as shown in FIG. 13, a large downward gas force is applied to the piston 101, which exceeds the upward inertia force in the figure. For this reason, a large downward force is applied to the cross head pin 104a of the cross head bearing portion 104 in most of the upward stroke and the downward stroke. For this reason, the lubricating oil is not supplied uniformly in the crosshead bearing portion 104, and a uniform and sufficient oil film is not formed.

  On the other hand, when the reduced-cylinder operation as described above is performed, dirt such as cylinder oil and sludge accumulates in the reduced-cylinder cylinder that does not perform fuel injection. For this reason, it is necessary to perform combustion operation by injecting fuel at regular intervals for the reduced cylinder, and to burn and remove those dirt. That is, it is necessary to repeat the reduced-cylinder operation and the combustion operation as appropriate for the cylinder to be reduced.

  When the reduced cylinder operation is performed, as a matter of course, in order to compensate for this, the output of the operating cylinder that performs fuel injection and combustion must be increased. In this operating cylinder, the reduced cylinder operation is not performed. In contrast, the gas power increases compared to the non-reducing cylinder operation in which the normal combustion operation is performed for all the cylinders. Further, during low-speed operation, the sliding speed between the bearing members in the crosshead bearing portion 104 becomes slow, thereby reducing the so-called wedge effect of the lubricating oil and causing a phenomenon that the oil film becomes thin.

  Therefore, when the reduced cylinder operation is performed, in addition to the situation in which the oil film is not sufficiently formed at the cross head bearing portion 104 when the cylinder is reduced, since the operation is performed at a low speed when the load is low, lubrication is performed during the combustion operation of the cylinder. The so-called wedge effect of oil is reduced, the oil film is thinned, and the gas force applied to the crosshead bearing portion 104 via the piston 101 is increased compared to the non-reducing cylinder operation, so that the lubricating performance of the crosshead bearing portion 104 is improved. Is significantly reduced, and there is a problem that severe wear occurs in the crosshead bearing portion 104.

  For this reason, in the two-cycle internal combustion engine having the crosshead 103, at the time of low load, the reduced-cylinder operation that can be expected to significantly improve fuel consumption compared with the above-described various conventional supercharging measures has not yet been realized. Is the actual situation.

  The present invention has been made to solve such a problem, and in a two-cycle internal combustion engine having a cross head, the wear of the cross head bearing portion is prevented, and a reduced cylinder operation at a low load is enabled. It is an object of the present invention to provide a reduced-cylinder operation method for an electronically controlled two-cycle internal combustion engine that can significantly improve fuel consumption of the internal combustion engine.

  In order to solve the above-mentioned problems, the means employed in the reduced-cylinder operation method of the electronically controlled two-cycle internal combustion engine of the present invention slides up and down in the cylinder of the electronically controlled two-cycle internal combustion engine having a plurality of cylinders. A moving piston, a piston rod connected to the piston and reciprocating up and down in the cylinder, a crosshead disposed in the crank chamber and connected to the piston rod and reciprocating up and down in the crank chamber, a crosshead and a crank A connecting rod that connects the shaft and cooperates with the crankshaft to convert reciprocating motion into rotational motion, a scavenging hole provided on the side wall of the cylinder for supplying scavenging, and a exhaust gas provided on the cylinder head of the cylinder. Reduction of an electronically controlled two-cycle internal combustion engine having an exhaust valve to be performed, an exhaust valve operating mechanism that operates the exhaust valve, and an electronic control device that controls the operation of the exhaust valve operating mechanism In the operation system, the electronic control unit performs a reduced-cylinder operation in which fuel is not injected into a part of the plurality of cylinders according to the load of the internal combustion engine, and the reduced-cylinder operation. The exhaust valve operating mechanism is sometimes operated to open the exhaust valve of the reduced cylinder that does not perform fuel injection in a range of crank angles different from the exhaust valve of the operating cylinder that performs fuel injection. The gas pressure applied to the piston is reduced.

  In the reduced-cylinder operation method of the electronically controlled two-cycle internal combustion engine of the present invention, the electronic control device operates without performing fuel injection on some of the plurality of cylinders according to the load of the internal combustion engine. When the reduced cylinder operation is performed, the exhaust valve operating mechanism is operated during the reduced cylinder operation so that fuel injection is not performed. Since the gas pressure applied to the piston of the reduced cylinder is lowered, it can be avoided that a large downward gas force is applied to the cross head bearing portion of the reduced cylinder.

  For this reason, it is possible to form a state in which the inertial force upward of the piston overcomes the downward gas force and the crosshead pin floats upward in the crosshead bearing portion for a certain period. Thereby, only a necessary and sufficient amount of fresh lubricating oil is uniformly introduced into the cross head bearing portion, and a uniform and optimum oil film can be formed on the cross head bearing portion.

  Therefore, even during the combustion operation between the reduced cylinders where the gas force is increased compared with the non-reduced cylinder operation, severe wear of the crosshead bearing portion can be prevented, thereby enabling the reduced cylinder operation at a low load. . Here, the non-reducing cylinder operation means performing normal combustion operation for all cylinders (the same applies hereinafter).

  In the reduced-cylinder operation method of the electronically controlled two-cycle internal combustion engine, the electronic control device operates the exhaust valve operating mechanism to open the exhaust valve of the reduced-cylinder cylinder only within a predetermined crank angle range including top dead center. It is desirable. This top dead center includes the vicinity of the top dead center.

  In this way, by opening the exhaust valve of the reduced cylinder during the reduced cylinder operation in a predetermined crank angle range including the top dead center where the maximum gas pressure is applied to the piston downward, the cross cylinder of the reduced cylinder It is possible to avoid a large downward gas pressure from being applied to the head bearing portion, an optimal oil film is formed on the cross head bearing portion, and wear prevention of the cross head bearing portion can be achieved at a higher level.

  In the reduced-cylinder operation method of the electronically controlled two-cycle internal combustion engine, the electronic control device operates the exhaust valve operating mechanism to move the exhaust valve of the reduced-cylinder cylinder so that at least the piston of the reduced-cylinder cylinder moves downward from the top dead center. It is desirable to keep the valve open until it moves to the position where the scavenging hole is opened. This top dead center includes the vicinity of the top dead center.

  As described above, at the time of the downward stroke in which the downward inertia force is applied to the exhaust valve of the reduction cylinder in addition to the gas pressure downward with respect to the piston during the reduction cylinder operation, at least the piston of the reduction cylinder is A large downward gas pressure is applied to the crosshead bearing of the reduced cylinder cylinder by opening the valve from the top dead center where the maximum gas pressure is applied to the position where the scavenging hole in the downward stroke is opened. Therefore, an optimal oil film is formed on the cross head bearing portion, and wear of the cross head bearing portion can be prevented very effectively.

  In the reduced-cylinder operation system of the electronically controlled two-cycle internal combustion engine, the electronic control unit operates the exhaust valve operating mechanism to move the exhaust valve of the reduced-cylinder cylinder over the entire stroke of the ascending stroke and the descending stroke of the piston of the reduced-cylinder cylinder. It is desirable to open the valve.

  In this way, by opening the exhaust valve of the reduction cylinder during the cylinder reduction operation over the entire stroke of the piston of the cylinder of the cylinder reduction cylinder, the gas pressure applied to the piston is extremely low over the entire stroke, and It becomes almost constant. Therefore, the wear of the crosshead bearing portion is extremely effectively prevented, the operation of the exhaust valve is simplified, and the exhaust temperature of the internal combustion engine can be lowered by scavenging.

  In the reduced-cylinder operation method of the electronically controlled two-cycle internal combustion engine, the electronic control unit operates the exhaust valve operating mechanism to close the scavenging hole in the upward stroke by the piston of the reduced-cylinder cylinder. It is desirable to open the valve only after the opening until the opening of the scavenging hole in the downward stroke.

  In this way, during the reduced cylinder operation, the exhaust valve of the reduced cylinder is opened only after the scavenging hole is closed in the upward stroke by the piston of the reduced cylinder cylinder until after the scavenging hole is opened in the downward stroke. Also, the gas pressure applied to the piston can be made extremely low over almost the entire stroke except when the scavenging holes are opened.

  Therefore, the wear of the crosshead bearing is prevented very effectively, and in this case, the scavenging cylinder is not scavenged, so that the exhaust temperature of the internal combustion engine can be raised. Further, by eliminating unnecessary scavenging, it is possible to solve the shortage of supercharging during low load operation.

  In the reduced-cylinder operation method of the electronically controlled two-cycle internal combustion engine, it is desirable that the electronic control device operates the exhaust valve operating mechanism to continuously open the exhaust valve of the reduced-cylinder cylinder when the valve is opened.

  Thus, by continuously opening the exhaust valve of the reduced cylinder cylinder when the valve is opened, the operation of the exhaust valve can be simplified and the fluctuation of the gas pressure applied to the piston can be prevented. Wear of the head bearing portion can be further prevented.

  In the reduced-cylinder operation method of the electronically controlled two-cycle internal combustion engine, it is desirable that the reduced-cylinder cylinder is operated without performing fuel injection at a rate of once every two or three rotations.

  Dirt such as cylinder oil and sludge accumulated during cylinder reduction by operating without reducing fuel injection at a rate of once every 2 or 3 rotations with respect to the cylinder with reduced cylinder, and by performing fuel operation with fuel injection. Can be efficiently removed by the combustion operation between the reduced cylinders, and the formation oil film of the lubricating oil in the crosshead bearing portion is optimally held, and wear of the crosshead bearing portion can be reliably prevented.

  In the reduced-cylinder operation method of the electronically controlled two-cycle internal combustion engine, it is desirable to inject lubricating oil into the crosshead bearing portion of the crosshead. Thus, by injecting the lubricating oil into the crosshead bearing portion, it is possible to further prevent wear of the crosshead bearing portion.

  An electronically controlled two-cycle internal combustion engine according to the present invention has a reduced-cylinder operation method in which an electronically controlled two-cycle internal combustion engine having a plurality of cylinders slides up and down in a cylinder, and is connected to the piston in the cylinder. A piston rod that reciprocates up and down, a crosshead that is disposed in the crank chamber and is connected to the piston rod and reciprocates up and down in the crank chamber, and connects the crosshead and the crankshaft to cooperate with the crankshaft. A connecting rod that converts reciprocating motion into rotational motion, a scavenging hole that is provided on the side wall of the cylinder to supply scavenging, an exhaust valve that is provided on the cylinder head of the cylinder for exhausting, and an exhaust valve that operates the exhaust valve In the reduced-cylinder operation method of an electronically controlled two-cycle internal combustion engine that includes a mechanism and an electronic control device that controls the operation of the exhaust valve operating mechanism, the electronic control device includes: Depending on the engine load, a reduced cylinder operation is performed without fuel injection for some of the cylinders, and the exhaust valve operating mechanism is operated during the reduced cylinder operation to perform fuel injection. The exhaust valve of the reduced cylinder that is not operated is opened in a crank angle range different from the exhaust valve of the working cylinder where fuel injection is performed, so that the gas pressure applied to the piston of the reduced cylinder is reduced. .

  That is, in the reduced-cylinder operation method of the electronically controlled two-cycle internal combustion engine of the present invention, the electronic control unit does not perform fuel injection on some of the plurality of cylinders according to the load of the internal combustion engine. When the reduced cylinder operation is performed, the exhaust valve operating mechanism is operated during the reduced cylinder operation, and the exhaust valve of the reduced cylinder in which fuel injection is not performed is different from the exhaust valve of the operating cylinder in which fuel injection is performed. In this range, the gas pressure applied to the piston of the reduced cylinder is reduced, so that it is possible to avoid applying a large downward gas force to the crosshead bearing portion of the reduced cylinder. For this reason, the oil film formation of the lubricating oil in the cross head bearing portion of the reduced cylinder cylinder is optimally performed, and severe wear of the cross head bearing portion can be prevented even if the cylinder reduction operation is performed at a low load.

  Therefore, in a two-cycle internal combustion engine having a crosshead, it is possible to reduce the wear of the crosshead bearing portion and to perform a reduced-cylinder operation at a low load, thereby significantly improving the fuel consumption. Play.

It is a figure which shows the structure of the reduced cylinder driving | running system of the electronically controlled 2 cycle internal combustion engine of this invention. It is a figure which shows the exhaust valve operating mechanism of the reduced cylinder driving | running system of the electronically controlled 2 cycle internal combustion engine of FIG. It is a figure which shows the detail of the exhaust valve action mechanism of FIG. FIG. 2 is a diagram showing opening areas of scavenging holes and exhaust valves in a descending and ascending stroke in the reduced-cylinder operation method of the electronically controlled two-cycle internal combustion engine of FIG. 1. FIG. 5 is a diagram showing a relationship between a cylinder volume of a reduced cylinder and a gas pressure in the cylinder in the reduced cylinder operation method of the electronically controlled two-cycle internal combustion engine of FIG. 4. FIG. 5 is a diagram showing a relationship between a piston inertia force of a reduced cylinder and a gas force against the piston in the reduced cylinder operation method of the electronically controlled two-cycle internal combustion engine of FIG. 4. It is a figure which shows the state of the crosshead bearing part at the time of the reduced cylinder operation of the reduced cylinder operation system of the electronically controlled two-cycle internal combustion engine of FIG. It is a figure which shows the opening area of the scavenging hole and exhaust valve in the downward and upward strokes of the reduced-cylinder operation method different from the reduced-cylinder operation method of FIG. It is a diagram which shows the relationship between the cylinder volume of a reduction cylinder and the gas pressure in a cylinder of the reduction cylinder driving | operation system of the electronically controlled 2 cycle internal combustion engine of FIG. It is a figure which shows the state of the crosshead bearing part at the time of reduced cylinder driving | running | working of the conventional reduced cylinder driving | running system of an electronically controlled 2 cycle internal combustion engine. It is a figure which shows the opening area of the scavenging hole and exhaust valve in the downward and upward strokes of the reduced-cylinder operation method of the conventional electronically controlled two-cycle internal combustion engine of FIG. It is a diagram which shows the relationship between the cylinder volume of a reduction cylinder and the gas pressure in a cylinder of the reduction cylinder driving | operation system of the conventional electronically controlled 2 cycle internal combustion engine of FIG. FIG. 11 is a diagram showing the relationship between the piston inertia force of the reduced cylinder and the gas force of the piston in the reduced cylinder operation method of the conventional electronically controlled two-cycle internal combustion engine of FIG. 10.

  An embodiment for carrying out the invention of a reduced-cylinder operation method for an electronically controlled two-cycle internal combustion engine according to the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a diagram showing a configuration of a reduced-cylinder operation method of an electronically controlled two-cycle internal combustion engine. Reference numeral 1 in FIG. 1 indicates a low-speed electronically controlled two-cycle uniflow diesel engine (internal combustion engine) as an example. In the engine 1, a plurality of cylinder heads 2, 3, and a plurality of cylinders 3 are arranged in a circumferential direction below the cylinder 3, scavenging holes 4 for introducing scavenging air into the cylinder 3, and provided at the top of the cylinder 3. An exhaust valve 21 and a piston 6 for exhausting the combustion gas are disposed. The engine 1 is provided with a plurality of such cylinders 3, and the electronic control unit 5 controls the fuel injection to each cylinder 3, ignition, the operation of the exhaust valve 21, and the like.

  A piston rod 7 connected to the lower part of the piston 6 and reciprocating up and down in the cylinder 3 is disposed in the crank chamber, and a cross head 8 connected to the piston rod 7 and reciprocating in the crank chamber up and down, and the cross head 8 The connecting rod 10 is connected to the crankshaft 11 and cooperates with the crankshaft 11 to convert the reciprocating motion into the rotational motion. The crosshead 8 and the connecting rod 10 are connected via a crosshead bearing portion 9.

  Lubricating oil is constantly supplied and injected from the lubricating oil supply device 12 of the engine 1 to the crosshead bearing portion 9. The exhaust valve 21 is operated by an exhaust valve operating mechanism 20, and the operation of the exhaust valve operating mechanism 20 is controlled by the electronic control device 5 of the engine 1.

  2 and 3 are views showing an exhaust valve operating mechanism 20 as an example. As shown in FIGS. 2 and 3, the exhaust valve operating mechanism 20 includes an exhaust valve 21, a hydraulic piston 22 that is attached to the upper end of the valve shaft 21 a of the exhaust valve 21 and opens the exhaust valve 21, and a valve An air spring 24 that is attached in the middle of the shaft 21a and closes the exhaust valve 21 (restoring operation) is accommodated.

  A damping actuator 25 is attached to the upper part 20 a of the exhaust valve operating mechanism 20. The damping actuator 25 has an actuator function for driving the hydraulic piston 22 and a damping function for suppressing the driving speed of the hydraulic piston 22, and is connected to the hydraulic cylinder 23 of the hydraulic piston 22 via the oil passage 61. Yes.

  A hydraulic block 30 that is separate from the exhaust valve driving device 20 is disposed on the side of the exhaust valve driving mechanism 20, and a directional control valve 31 and an accumulator 35 are attached to the hydraulic block 30. Further, an electromagnetic solenoid 32 for switching and controlling the direction control valve 31 is attached to the direction control valve 31. The operation of the electromagnetic solenoid 32 is controlled by the electronic control unit 5.

  Oil passages 30a, 30b, and 30c are provided in the hydraulic block 30 and are connected to corresponding ports (not shown) of the direction control valve 31. The hydraulic source 33 includes a hydraulic pump 34, an accumulator 35, and the like. The hydraulic pump 34 is connected to the oil passage 30 a via a high pressure pipe 62, and the accumulator 35 is connected to the high pressure pipe 62.

  The oil passage 30 a guides high pressure oil pressure from the oil pressure source 33 to the direction control valve 31. The oil passage 30 b is connected to the damping actuator 25 via the high pressure pipe 63. The oil passage 30 c discharges hydraulic pressure from the direction control valve 31 to the tank 37 through the low pressure pipe 64. The damping actuator 25 has an actuator piston 27 slidably accommodated in an actuator cylinder 26.

  The actuator cylinder 26 is provided with a port 26a on one end face and a port 26b on the other end face. The port 26 a is connected to the high pressure pipe 63, and the port 26 b is connected to the hydraulic cylinder 23 attached to the exhaust valve 21 via the oil passage 61.

  A check valve 40 that permits movement of hydraulic pressure from the direction control valve 31 to the damping actuator 25 is connected to the port 26a of the damping actuator 25, and hydraulic pressure from the hydraulic cylinder 23 to the damping actuator 25 is connected to the port 26b. A check valve 41 is connected to allow the movement. A first bypass oil passage 42 is connected to the check valve 40 in parallel, and a second bypass oil passage 43 is connected to the check valve 41 in parallel.

  The first bypass oil passage 42 and the second bypass oil passage 43 are each configured by connecting a plurality of oil passages in parallel, and are sequentially closed in accordance with the movement of the actuator piston 27, thereby providing a damping function. Have come to have.

  Next, the operation of the reduced cylinder operation method of the electronically controlled two-cycle internal combustion engine of the present invention will be described. 4 is a view showing the opening area of the scavenging holes and the exhaust valve in the downward and upward strokes of the reduced cylinder operation method of the electronically controlled two-cycle internal combustion engine of FIG. 1, and FIG. 5 is the electronically controlled two-cycle internal combustion engine of FIG. FIG. 6 is a diagram showing the relationship between the cylinder volume of the reduction cylinder of the reduction cylinder operation method of the engine and the gas pressure in the cylinder, FIG. 6 is a diagram showing the relationship between the piston inertia force of the reduction cylinder cylinder and the gas force against the piston; FIG. 7 is a view showing a state of the cross head bearing portion during the reduced cylinder operation of the reduced cylinder operation method of the electronically controlled two-cycle internal combustion engine of FIG.

  The electronic control unit 5 does not inject fuel and does not perform combustion for the reduced cylinder 3 that is reduced among the plurality of cylinders. However, for an operating cylinder that performs combustion by injecting fuel, a corresponding increase in output is required corresponding to the load at that time, and this increases the indicated mean effective pressure in the cylinder. As a result, the supercharging of the supercharger is improved. Scavenging is supplied to the scavenging hole 4 of the reduced cylinder 3 in the same manner as during fuel injection.

  In the reduced-cylinder operation, fuel injection is stopped at a rate of once every two or three rotations for each cylinder 3 to be reduced, and the fuel is injected and burned in the same manner as in the operating cylinder. As described above, the fuel injection to the reduced cylinder 3 is stopped once every two or three rotations because the combustion such as cylinder oil and sludge accumulated at the time of the reduced cylinder is efficiently performed by the combustion operation between the reduced cylinders. It is for removing well. In addition, as will be described later, the lubricating oil forming oil film in the cross head bearing portion 9 is optimally held, and the wear of the cross head bearing portion 9 is reliably prevented.

  As shown in FIG. 4, in the reduced cylinder 3 of the engine 1, the exhaust valve 21 is continuously fully opened over the entire stroke of the upward stroke and the downward stroke of the piston 6. For this reason, as shown in FIGS. 5 and 6, the gas pressure in the cylinder 3 becomes extremely low over the entire stroke of the ascending stroke and the descending stroke, and becomes almost constant. In other words, it can be said that only the inertial force is applied to the cross head bearing portion 9 of the reduced cylinder 3 during the upward and downward strokes.

  During the conventional reduced cylinder operation, as shown in FIGS. 12 and 13, a large downward gas pressure is applied to the crosshead bearing portion 9 due to the compression of the gas in the cylinder 3. On the other hand, in this electronically controlled two-cycle diesel engine, the gas pressure is substantially constant during the entire cylinder reduction operation, and the maximum gas pressure is the maximum gas pressure during the conventional cylinder reduction operation shown in FIG. It is reduced to 1 / (30-40).

  Therefore, as shown in FIG. 6, in the crosshead bearing portion 9 of the reduced cylinder 3, when the piston 6 is lifted, an upward force due to an upward inertial force is applied to the piston 6 as it approaches the top dead center. Further, when the piston 6 is lowered, an upward force due to an upward inertia force is applied from the top dead center to a certain crank angle.

  Therefore, as shown in FIG. 7, while this upward force is applied, it is possible to form a state in which the cross head pin 9 a of the cross head bearing portion 9 floats upward in the cross head bearing portion 9. . As a result, only a necessary and sufficient amount of fresh lubricating oil is uniformly introduced into the crosshead bearing portion 9, and a uniform and optimum oil film can be formed on the crosshead bearing portion 9.

  Therefore, even during the combustion operation between the reduced cylinders where the gas force increases compared with the non-reduced cylinder operation, severe wear of the crosshead bearing portion can be prevented even if a large downward force is applied as the output increases. Thereby, the reduced-cylinder operation at the time of low load becomes possible. Furthermore, since the lubricating oil is always injected into the crosshead bearing portion 9 from the lubricating oil supply device 12, this also prevents wear.

  As described above, the exhaust valve 21 of the reduction cylinder 3 is opened over the entire stroke of the piston 6 of the reduction cylinder 3 during the reduction stroke operation. The wear of the portion 9 is prevented very effectively, and the exhaust valve 21 is always fully open during the reduced-cylinder operation, and the operation of the exhaust valve 21 can be simplified.

  Further, since the exhaust valve 21 is opened when the scavenging hole 4 is opened, scavenging is performed and the exhaust temperature of the engine 1 can be lowered. That is, the above-described reduced-cylinder operation method is a reduced-cylinder operation method suitable for lowering the exhaust temperature of the engine 1.

  FIG. 8 is a view showing the opening area of the scavenging hole and the exhaust valve in the downward and upward strokes of the reduced-cylinder operation method different from the reduced-cylinder operation method of FIG. 4, and FIG. It is a diagram which shows the relationship between the cylinder volume of a reduction cylinder and the gas pressure in a cylinder of the reduction cylinder operation system of a cycle internal combustion engine.

  As shown in FIG. 8, in this electronically controlled two-cycle diesel engine, the electronic control unit 5 operates the exhaust valve operating mechanism 20 so that the exhaust valve 21 of the reduced cylinder 3 is connected to the piston 6 of the reduced cylinder 3. The valve is opened only after the scavenging hole 4 is closed in the up stroke until the scavenging hole 4 is opened in the down stroke.

  As shown in FIG. 9, also in this case, the gas pressure in the cylinder 3 is up to 1 / (30-40) of the maximum gas pressure during the conventional reduced cylinder operation over the entire stroke of the ascending stroke and the descending stroke. Decrease to become extremely low and almost constant. That is, it can be said that only the inertial force is applied to the cross head bearing portion 9 of the reduced cylinder 3 during the ascending and descending strokes as in the case where the exhaust valve 21 is fully opened in the entire stroke.

  That is, in the conventional reduced-cylinder operation, as shown in FIGS. 12 and 13, the crosshead bearing portion 9 was subjected to a large downward gas pressure due to the compression of the gas in the cylinder 3. On the cross head bearing portion 9 of the cylindrical cylinder 3, when the piston 6 is raised, an upward force due to the upward inertia force of the piston 6 is applied as it approaches the top dead center, and the piston 6 is lowered. Sometimes an upward force due to an upward inertia force is applied from the top dead center to a certain crank angle.

  Therefore, it is possible to form a state in which the cross head pin 9a of the cross head bearing portion 9 floats upward in the cross head bearing portion 9 while this upward force is applied. As a result, only a necessary and sufficient amount of fresh lubricating oil is uniformly introduced into the crosshead bearing portion 9, and a uniform and optimum oil film can be formed on the crosshead bearing portion 9.

  Therefore, even during the combustion operation between the reduced cylinders where the gas force increases compared with the non-reduced cylinder operation, severe wear of the crosshead bearing portion can be prevented even if a large downward force is applied as the output increases. Thereby, the reduced-cylinder operation at the time of low load becomes possible. Furthermore, since the lubricating oil is always injected into the crosshead bearing portion 9 from the lubricating oil supply device 12, this also prevents wear.

  In this way, during the reduced cylinder operation, the exhaust valve 21 of the reduced cylinder 3 is closed after the scavenging hole 4 is closed in the upward stroke of the piston 6 of the reduced cylinder 3 until after the scavenging hole 4 is opened in the downward stroke. Even when the valve is opened only for a while, the wear of the crosshead bearing portion 9 is extremely effectively prevented as described above, and the exhaust valve 21 is continuously fully opened when the valve is opened. It can be simplified.

  However, even if the scavenging hole 4 is opened, scavenging is not performed because the exhaust valve 21 is closed during that time. Therefore, the exhaust temperature of the engine 1 does not decrease due to scavenging from the reduced cylinder cylinder 3. That is, the above-described reduced-cylinder operation method is a reduced-cylinder operation method suitable for increasing the exhaust temperature of the engine 1. Further, in this case, unnecessary scavenging can be eliminated, thereby improving the supercharging performance during low-load operation.

  When a reduced-cylinder operation is performed with some cylinders, it is natural that to compensate for this, the output of the working cylinder that performs fuel injection and combustion must be increased. The gas force increases compared to the non-reducing cylinder operation in which the normal combustion operation is performed for all the cylinders without performing the cylinder operation.

  However, in the reduced-cylinder operation system of the electronically controlled two-cycle internal combustion engine, in any of the above-described control systems, the reduced-cylinder cylinder that does not perform fuel injection by operating the exhaust valve operating mechanism 20 during the reduced-cylinder operation. 3 is opened in a range of a crank angle different from that of the exhaust valve of the working cylinder in which fuel injection is performed, so that the gas pressure applied to the piston of the reduced cylinder cylinder is lowered.

  Therefore, it is possible to avoid a large downward gas force from being applied to the piston 6 when the cylinder is reduced, and fresh lubricating oil is uniformly and necessaryly introduced into the crosshead bearing 9 so that the crosshead bearing 9 A uniform and optimal oil film can be formed.

  For this reason, even during the combustion operation between the reduced cylinders where the gas force is increased compared with the non-reduced cylinder operation, severe wear of the crosshead bearing portion can be prevented even if a large downward force is applied as the output increases. Thereby, the reduced-cylinder operation at the time of low load becomes possible.

  For example, as in the above-described two reduced-cylinder operation methods, the electronic control unit 5 operates the exhaust valve operating mechanism 20 so that the exhaust valve 21 of the reduced-cylinder cylinder 3 has a top dead center at which the gas compression force is maximized. By opening the valve in a predetermined crank angle range including the above, wear prevention of the crosshead bearing portion 9 is achieved at a higher level. The top dead center includes the vicinity of the top dead center before and after the top dead center.

  Further, for example, as in the above-described two reduced-cylinder operation methods, the electronic control device 5 operates the exhaust valve operating mechanism 20 so that the exhaust valve 21 of the reduced-cylinder cylinder 3 and at least the piston 6 of the reduced-cylinder cylinder 3 is moved. In the downward stroke, the valve is opened from the top dead center (including the vicinity of the top dead center) to the position where the scavenging hole 4 in the downward stroke is opened. Prevention is very effective.

  Further, by continuously opening the exhaust valve 21 of the reduced cylinder 3 when the valve is opened, the operation of the exhaust valve 21 can be simplified and extreme fluctuations in the gas pressure applied to the piston 6 can be prevented. As a result, the wear of the crosshead bearing 9 can be further prevented.

  Note that the above-described reduced-cylinder operation method of the electronically controlled two-cycle internal combustion engine is merely an example, and it is needless to say that various modifications are possible.

  The reduced-cylinder operation method of the electronically controlled two-cycle internal combustion engine of the present invention is not necessarily limited to the low-speed electronically-controlled two-cycle diesel engine, and similarly, the gas pressure in the cylinder during the reduced-cylinder operation is reduced. In an internal combustion engine having a portion that is affected and significantly worn out, the present invention can be widely used when the reduced cylinder operation is safely realized.

1 engine (internal combustion engine)
2 Cylinder head 3 Cylinder (reducing cylinder)
4 Scavenging hole 5 Electronic control device 6 Piston 7 Piston rod 8 Cross head 9 Cross head bearing portion 9a Cross head pin 10 Connecting rod 11 Crankshaft 12 Lubricating oil supply device 20 Exhaust valve operating mechanism 21 Exhaust valve 25 Damping actuator 30 Hydraulic block 31 Direction Control valve 32 Electromagnetic solenoid 35 Accumulator 63 High pressure pipe 101 Piston 102 Piston rod 103 Crosshead 104 Crosshead bearing portion 104a Crosshead pin 105 Crankshaft 106 Connecting rod 107 Exhaust valve

Claims (8)

A piston (6) sliding up and down in the cylinder of an electronically controlled two-cycle internal combustion engine (1) having a plurality of cylinders, and a piston rod (7) connected to the piston and reciprocating up and down in the cylinder ), A cross head (8) disposed in the crank chamber and connected to the piston rod and reciprocating up and down in the crank chamber, and the cross head and the crank shaft (11) are connected to each other to connect the crank shaft Are provided in a connecting rod (10) for converting reciprocating motion into rotational motion in cooperation with each other, a scavenging hole (4) provided in a side wall of the cylinder for supplying scavenging, and a cylinder head (2) of the cylinder. An electronic control type comprising an exhaust valve (21) for exhausting, an exhaust valve operating mechanism (20) for operating the exhaust valve, and an electronic control device (5) for controlling the operation of the exhaust valve operating mechanism In the reduced-cylinder operation mode cycle internal combustion engine,
The electronic control unit performs a reduced-cylinder operation in which some cylinders of the plurality of cylinders are operated without performing fuel injection according to a load of the internal combustion engine, and at the time of the reduced-cylinder operation, The exhaust valve operating mechanism is operated to open the exhaust valve of the reduced cylinder (3) where the fuel injection is not performed in a range of a crank angle different from the exhaust valve of the operating cylinder where the fuel injection is performed. A reduced-cylinder operation method for an electronically controlled two-cycle internal combustion engine, wherein a gas pressure applied to the piston of the reduced-cylinder cylinder is reduced. The electronic control unit (5) operates the exhaust valve operating mechanism (20) to open the exhaust valve (21) of the reduced cylinder (3) within a predetermined crank angle range including top dead center. The reduced-cylinder operation method for an electronically controlled two-cycle internal combustion engine according to claim 1, wherein The electronic control unit (5) operates the exhaust valve operating mechanism (20) so that the exhaust valve (21) of the reduced-cylinder cylinder (3) moves at least the piston (6) of the reduced-cylinder cylinder. The reduced cylinder of the electronically controlled two-cycle internal combustion engine according to claim 1 or 2, wherein the valve is opened from a dead center until the scavenging hole is moved to a position where the scavenging hole in the downward stroke is opened. Driving method. The electronic control unit (5) operates the exhaust valve operating mechanism (20) to cause the exhaust valve (21) of the reduced cylinder (3) to move to the piston (6) of the reduced cylinder (3). The reduced-cylinder operation method for an electronically controlled two-cycle internal combustion engine according to any one of claims 1 to 3, wherein the valve is opened over the entire stroke of an ascending stroke and a descending stroke. The electronic control unit (5) operates the exhaust valve operating mechanism (20) to move the exhaust valve (21) of the reduced cylinder (3) in the upward stroke by the piston (6) of the reduced cylinder. 4. The electronically controlled two-stroke cycle according to claim 1, wherein the valve is opened only after the scavenging hole (4) is closed and after the scavenging hole is opened in a downward stroke. 5. Reduced cylinder operation method for internal combustion engines. The electronic control unit (5) operates the exhaust valve operating mechanism (20) to continuously open the exhaust valve (21) of the reduced cylinder (3) when the valve is opened. 6. A reduced-cylinder operation system for an electronically controlled two-cycle internal combustion engine according to any one of claims 1 to 5. The electronic control type 2 according to any one of claims 1 to 6, characterized in that it operates without performing the fuel injection at a rate of once every two or three rotations with respect to the reduced cylinder (3). Reduced cylinder operation method for cycle internal combustion engine. The reduced cylinder operation method for an electronically controlled two-cycle internal combustion engine according to any one of claims 1 to 7, characterized in that lubricating oil is injected into a crosshead bearing (9) of the crosshead (8).

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