JP2016084795A - Engine operation system of vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine operation system for a vessel capable of coping with third regulation of NOX.SOLUTION: An engine operation system for a vessel includes a main gas fuel injection valve (5) for injecting gas fuel at a high pressure into a cylinder (1), a pilot fuel injection valve (6) of diesel fuel, a main gas fuel supply device (8) for supplying high pressure gas fuel, a sub gas fuel injection valve (7) for injecting the gas fuel into the cylinder, a sub gas fuel supply device (10) for supplying the gas fuel to the sub gas fuel injection valve, and a controller (16) for adjusting an engine load by controlling operation of the main gas fuel supply device and the sub gas fuel supply device. The controller pre-injects all of the required gas fuel from the sub gas fuel injection valve into the cylinder and suppresses a discharge amount of NOX to be a prescribed value or less when the engine load is equal to or less than a prescribed load. The vessel has a GPS receiver, and the controller adjusts the engine load to be the prescribed load or less when it is determined that the vessel navigates within a prescribed sea area based on position information of the GPS receiver.SELECTED DRAWING: Figure 10

Description

  The present invention relates to an engine operating system for a ship equipped with a gas injection engine whose main fuel is a gas fuel such as natural gas.

  In recent years, a clean energy source has been demanded from the viewpoint of environmental conservation. From this point of view, a gas injection engine that uses gas fuel such as natural gas as its main fuel and injects high-pressure gas fuel into a cylinder after pilot fuel injection for ignition is expected. In the gas injection engine, it is necessary to inject high-pressure gas fuel into the cylinder in a short period of time in order to improve thermal efficiency due to the characteristics of the fuel.

  The problem of knocking due to self-ignition occurs in the Otto cycle premixing type gas engine in which all the gas fuel is premixed and combusted before pilot injection for ignition (for example, Patent Documents). 1), especially when the gas engine is under a high load or when the fuel injection amount is large.

  On the other hand, in the above-described gas injection engine serving as a diesel cycle, since all the gas fuel is injected into the cylinder after the pilot fuel injection, no knocking problem has occurred. From this point of view, the spread of gas injection engines is expected.

  For this reason, gas injection engines also require further improvements in thermal efficiency to reduce costs by reducing the amount of gas fuel used and to contribute to environmental conservation by reducing the amount of exhaust gas. Yes.

  In addition, it is effective to inject gas fuel at a higher pressure as a method for improving thermal efficiency in a gas injection engine. However, in order to ensure safety against high-pressure gas, a higher level of safety measures is required. At the same time, there is a problem in that the power energy required to increase the pressure is increased.

  Furthermore, the conventional gas injection engine combusts basically in the same thermal cycle as that of a diesel engine, so that there is a problem that NOx is generated relatively frequently. For this reason, it is necessary to further suppress the generation of NOx from the viewpoint of environmental conservation.

  Therefore, the applicant of the present application proposes a new fuel injection system for a gas injection engine according to Japanese Patent Application No. 2014-65973, and can improve the thermal efficiency without injecting the gas fuel at a higher pressure than the current level. Occurrence can be suppressed, and environmental conservation and cost reduction can be achieved. This gas injection engine is an epoch-making thing which can solve the above-mentioned problem at a stretch.

JP-A-11-324805 Japanese translation of PCT publication No. 2002-066813

  On the other hand, in the ship as well, in recent years, active efforts have been made to protect the environment. The “Rules” came into effect on May 19, 2005, and the amendment was adopted by the 58th Marine Environment Protection Committee (MEPC58, October 2008). Both NOX and SOX regulations are phased in. Regulations were strengthened.

  In particular, in the third NOx regulations that are decided to be implemented from January 2016, NOx emissions must be reduced by about 76% in the specified sea area compared to the previous second regulation values. As a result, significant enhancements were made. As this specific sea area, a sea area within 200 nautical miles along the US and Canada coasts and a US Caribbean sea area are currently designated.

  For this reason, it has been difficult to cope with only a slight improvement of the engine itself that has been performed so far, and the introduction of additional technology has become indispensable. In addition, there are selective catalytic reduction denitration equipment (SCR) and exhaust gas recirculation system (EGR) as countermeasures for NOx currently considered as additional technologies, but these are all large and complex. It also leads to a significant cost increase.

  The present invention has been made to solve such a problem, and the third NOX is imminent even without a large, complicated and costly accessory device such as SCR or EGR. It is an object to provide an engine operation method of a ship that can comply with regulations.

  In order to solve the above problems, the means employed by the present invention is a marine engine operating system equipped with a gas injection engine using gas fuel as a main fuel as a main engine for propulsion, and the gas injection engine is a cylinder A main gas fuel injection valve disposed in the head for injecting gas fuel into the cylinder at a high pressure, and a pilot fuel injection valve for injecting diesel fuel into the cylinder before injection of gas fuel from the main gas fuel injection valve; A main gas fuel supply device for supplying high pressure gas fuel to the main gas fuel injection valve, a sub gas fuel injection valve for injecting gas fuel into the cylinder of the gas injection engine, and a sub gas fuel injection valve for supplying gas fuel to the sub gas fuel injection valve A controller for adjusting the engine load by controlling the operation of the gas fuel supply device, the main gas fuel supply device, and the auxiliary gas fuel supply device And the controller controls the operation of the auxiliary gas fuel supply device so that all or part of the gaseous fuel required for combustion from the auxiliary gas fuel injection valve before the diesel fuel is pilot injected from the pilot fuel injection valve In the engine operation system of the ship, the remaining fuel gas required for combustion is injected into the cylinder at high pressure from the main gas fuel injection valve after the diesel fuel is pilot injected from the pilot fuel injection valve. Is the pre-injection rate which is the mass ratio of the gas fuel pre-injected from the auxiliary gas fuel injection valve before the pilot fuel injection with respect to the total gas fuel required for combustion when the engine load of the gas injection engine is less than the predetermined load To reduce the NOx emission of the gas injection engine below a predetermined value. The

  First, the ship according to the present invention is equipped with a gas injection engine whose main fuel is a gas fuel such as natural gas, and the gas fuel such as natural gas has much less sulfur content than diesel oil or the like. In addition, it is possible to clear all the current and soon-to-be-applied regulation values regarding the recent SOX regulation values and particulate matter (PM).

  On the other hand, this gas injection engine is provided with a secondary gas fuel injection valve. This secondary gas fuel injection valve is a gas fuel which is required for combustion before diesel fuel is pilot-injected from the pilot fuel injection valve. All or part of the fuel is supplied from the auxiliary gas fuel supply device and pre-injected into the cylinder. The main gas fuel injection valve injects the remainder of the gas fuel required for combustion after pilot injection into the cylinder at a high pressure.

  As described above, in a gas injection engine, in order to improve thermal efficiency, it is required to inject a higher-pressure gas fuel into the cylinder in a short time. However, in the gas injection engine of the present invention, much of the generated heat required for combustion is injected from the auxiliary gas fuel injection valve before the pilot fuel injection, thereby igniting the pilot fuel injection and thereafter increasing the gas temperature. Since the amount of gas fuel injected from the main gas fuel injection valve after pilot fuel injection can be reduced, it is necessary and sufficient even if the injection pressure of the gas fuel is not increased any more. Gas fuel can be injected into the cylinder in a short time. Thereby, thermal efficiency can be improved.

  In addition, if all or part of the gas fuel is injected before pilot injection and ignited by pilot injection in this way, the combustion becomes lean burn combustion similar to lean premixed combustion in a diesel engine. The generation of NOx can be surely reduced.

  In particular, when the engine load is equal to or lower than a predetermined load, this gas injection engine has a mass ratio of the gas fuel pre-injected from the auxiliary gas fuel injection valve before the pilot fuel injection to the total gas fuel required for combustion. Since a certain pre-injection rate is set to 100%, lean burn combustion is performed at a low load equal to or lower than a predetermined load, and the NOx emission amount can be suppressed extremely low.

  On the other hand, the conventional premixed gas engine has a characteristic that occurrence of knocking due to gas injection is small in a low load region. Therefore, even if a relatively large amount of gas fuel is pre-injected at a low load in this gas injection engine, the possibility of knocking is extremely low.

  In other words, if this ship's gas injection engine is operated at a low load where the engine load is less than or equal to a predetermined load, the NOx emissions can be reduced while improving the thermal efficiency and reducing the possibility of knocking. It can be suppressed to an extremely low predetermined value or less.

In the above-described ship engine operation system, the controller desirably sets the pre-injection rate to 50% or less when the engine load of the gas injection engine exceeds a predetermined load.
As described above, it is known that the conventional premixed gas engine has a higher possibility of knocking due to gas injection in a high load region, and the pre-injection amount of gas fuel is within a certain range at high load. It is necessary to keep it down. Therefore, particularly by setting the pre-injection rate to 50% or less, it is possible to optimize ignition by pilot fuel injection and subsequent increase in gas temperature while preventing occurrence of knocking.

  And, if this high-load operation is performed in the sea area where the regulations before the third regulation are applied, for example, all current and soon-to-be-applied regulation values regarding NOx emissions will be cleared. Can do.

Further, in order to solve the above-mentioned problems, the means employed by the present invention is a ship engine operating system equipped with a gas injection engine using gas fuel as a main fuel as a main engine for propulsion, and the gas injection engine is A main gas fuel injection valve disposed in the cylinder head for injecting gas fuel into the cylinder at high pressure, and a pilot fuel injection valve for injecting diesel fuel into the cylinder before injection of gas fuel from the main gas fuel injection valve A main gas fuel supply device for supplying high pressure gas fuel to the main gas fuel injection valve, a sub gas fuel injection valve for injecting the gas fuel into the cylinder of the gas injection engine, and supplying gas fuel to the sub gas fuel injection valve A secondary gas fuel supply device that controls the engine load by controlling the operation of the main gas fuel supply device and the secondary gas fuel supply device. And a controller for controlling the operation of the auxiliary gas fuel supply device so that all of the gas fuel required for combustion from the auxiliary gas fuel injection valve is injected before the diesel fuel is pilot injected from the pilot fuel injection valve. Or the engine operation system of the ship which injects the remaining part of the gas fuel required for combustion from the main gas fuel injection valve into the cylinder at a high pressure after the diesel fuel is pilot injected from the pilot fuel injection valve. When the ship further includes a GPS receiver, and the controller determines that the ship is navigating within the predetermined sea area based on the position information supplied from the GPS receiver, the engine load is reduced below the predetermined load. The mass of gas fuel pre-injected from the secondary gas fuel injection valve before pilot fuel injection for all gas fuel required for combustion The pre-injection rate is expedient to 100%, is to suppress the NOX emissions of gas injection engine to a predetermined value or less.

  As described above, when the controller determines that the ship is navigating in the predetermined sea area based on the position information supplied from the GPS receiver, the engine load is adjusted to be equal to or lower than the predetermined load and is necessary for combustion. The pre-injection rate, which is the mass ratio of the gas fuel pre-injected from the auxiliary gas fuel injection valve before the pilot fuel injection, with respect to the total gas fuel is set to 100%, and the NOx emission amount of the gas injection engine is suppressed to a predetermined value or less. This makes it possible to automatically reduce the NOx emission amount to a very low amount in a predetermined sea area, for example, to 3.4 g / kWh or less, which is the third regulation value of the NOx emission amount. Others are the same as the case of the means which another above-mentioned this invention employ | adopts.

  In the engine operating system of the ship, the controller determines that the ship is navigating outside the predetermined sea area based on the position information supplied from the GPS receiver, and the engine load is equal to or less than the predetermined load. Therefore, it is desirable to set the pre-injection rate to 50% or more.

  When it is determined that the ship is navigating outside the predetermined sea area and the required engine load is less than the predetermined load, it is desirable to perform pre-injection according to the original performance of the gas injection engine. This can be achieved by setting the pre-injection rate to 50% or more.

  As described above, when this predetermined sea area is, for example, a sea area to which the third regulation of NOx emissions is applied, it is necessary to perform special pre-injection to reduce the NOx emissions to the smallest possible amount. However, in other sea areas, even if pre-injection according to the original performance of the gas injection engine is performed in this way, all of the current and soon-to-be-applied regulation values can be cleared.

  In the ship engine operation system, the controller sets the pre-injection rate to 100% at a low load immediately after starting the gas injection engine, and increases the pre-injection rate from 100% to 50% until the engine load increases to a predetermined load. The load point for decreasing from 100% to less than 100% pre-injection rate when the load increases is made higher than the load point for increasing from less than 100% to 100% pre-injection rate when the load decreases. Is desirable.

  Thus, a constant hysteresis is provided between the load point at which the pre-injection rate is reduced from 100% to less than 100% when the load is increased and the load point at which the pre-injection rate is increased from less than 100% to 100% when the load is reduced. By providing, control regarding the pre-injection of gas fuel can be stabilized.

  In the engine operating system of the ship, the controller determines that the ship is navigating outside the predetermined sea area based on the position information supplied from the GPS receiver, and the engine load exceeds the predetermined load. Therefore, it is desirable that the pre-injection rate is 50% or less.

  As described above, it is known that the conventional premixed gas engine has a higher possibility of knocking due to gas injection in a high load region, and the pre-injection amount of gas fuel is within a certain range at high load. It is necessary to keep it down. Therefore, by preventing the occurrence of knocking by pre-injecting gas fuel in an amount of 50% or less in the mass ratio of the gas fuel necessary for combustion in particular, the ignition by pilot fuel injection and the subsequent The gas temperature rise can be further optimized.

  If this high-load operation is performed outside the prescribed sea area, for example, in the sea area where the regulations before the third regulation of NOx emissions are applied, current regulations on NOx emissions and regulations that will soon be applied All values can be cleared.

  In the ship engine operation system, the predetermined load of the engine load is preferably set within a range of, for example, a load of 50 to 70%.

  If the load is less than 50%, there is a risk that the navigation of the ship may be hindered. If the load exceeds 70%, there is a concern about the occurrence of knocking seen in the lean burn engine as described above. This is because the ignition and subsequent gas temperature rise cannot be optimized.

  In the ship engine operating system, the predetermined value of the NOx emission amount is preferably set to 3.4 g / kWh, which is a third regulation value for an engine having an engine speed of less than 130 rpm, for example. In this way, the predetermined value of the NOx emission amount is set to, for example, the third regulation value 3.4 g / kWh for the engine having an engine speed of less than 130 rpm, thereby reliably clearing the third regulation regarding the NOx emission amount. can do.

  In the above-described ship engine operation system, it is desirable that the auxiliary gas fuel injection valve of the gas injection engine is disposed on the side of the cylinder to inject low-pressure gas fuel into the cylinder.

  In this way, the auxiliary gas fuel injection valve of the gas injection engine is disposed on the side of the cylinder, and low pressure gas fuel is injected into the cylinder from the auxiliary gas fuel injection valve, so that it is necessary and sufficient for pre-injection. Combustion is obtained, and the amount of gas fuel that must be handled as high-pressure gas can be reliably reduced, thereby improving safety. In addition, it is possible to suppress the power energy necessary for increasing the pressure of the gas fuel, thereby reducing the cost.

  In the engine operating system of the ship, it is desirable that the auxiliary gas fuel injection valve of the gas injection engine pre-injects the gas fuel into the cylinder at a low pressure of 5 to 15 bar.

  Thus, by pre-injecting gas fuel into the cylinder at a low pressure of 5 to 15 bar from the auxiliary gas fuel injection valve of the gas injection engine, the ignition by pilot fuel injection and the subsequent gas temperature increase are optimized. be able to.

  In the ship engine operating system, the sub-gas fuel injection valve of the gas injection engine may pre-inject gas fuel into the cylinder at a predetermined time within a range of 80 ° to 120 ° after bottom dead center at the crank angle. desirable.

Thus, when the pre-injection is a low-pressure injection, the gas fuel is pre-injected into the cylinder at a predetermined time within the range of 80 ° to 120 ° after the bottom dead center at the crank angle from the auxiliary gas fuel injection valve. Thereby, the ignition by pilot fuel injection and the subsequent gas temperature increase can be optimized.

  In the above-described ship engine operating system, the sub-gas fuel injection valve of the gas injection engine comprises a main gas fuel injection valve that is disposed in the cylinder head and injects main gas fuel into the cylinder at a high pressure. It is desirable that the main gas fuel injection device comprises a main gas fuel supply device for supplying high-pressure gas fuel to the main gas fuel injection valve.

  The gas fuel injected from the auxiliary gas fuel injection valve before the pilot fuel injection does not necessarily have to be at a low pressure, and the heat generation at the initial stage of combustion is brought close to ideal by high pressure injection from the main gas fuel injection valve. Can do. Thus, by performing the high-pressure gas fuel injection from the main gas fuel injection valve before and after the pilot fuel injection, it is possible to improve the thermal efficiency without further increasing the pressure of the gas fuel.

  In particular, the auxiliary gas fuel injection valve is a main gas fuel injection valve that is provided in the cylinder head and injects main gas fuel into the cylinder at a high pressure. It is not necessary to separately provide a gas fuel supply mechanism for supplying gas fuel to the injection valve, and an increase in cost can be avoided.

  In the engine operating system of the ship, it is desirable that the auxiliary gas fuel injection valve of the gas injection engine pre-injects the gas fuel into the cylinder at a high pressure of 200 to 300 bar.

  Thus, by pre-injecting gas fuel into the cylinder at a high pressure of 200 to 300 bar from the auxiliary gas fuel injection valve, it is possible to optimize ignition by pilot fuel injection and the subsequent increase in gas temperature.

  In the ship engine operating system, the sub-gas fuel injection valve of the gas injection engine may pre-inject gas fuel into the cylinder at a predetermined time within a range of 120 ° to 160 ° after bottom dead center at the crank angle. desirable.

  Thus, when the pre-injection is high-pressure injection, the gas fuel is pre-injected into the cylinder at a predetermined time within the range of 120 ° to 160 ° after the bottom dead center at the crank angle from the auxiliary gas fuel injection valve. Thereby, the ignition by pilot fuel injection and the subsequent gas temperature increase can be optimized.

  In the above-described ship engine operation system, it is preferable that the auxiliary gas fuel supply device of the gas injection engine includes an interlock mechanism that prevents the gas fuel from being injected beyond a predetermined time from the auxiliary gas fuel injection valve.

  As described above, the auxiliary gas fuel supply device of the gas injection engine includes the interlock mechanism that prevents the gas fuel from being injected from the auxiliary gas fuel injection valve beyond a predetermined time. Continuous injection of gas fuel from the injection valve is reliably prevented, and safety is improved.

The ship engine operating system of the present invention is a ship engine operating system equipped with a gas injection engine that uses gas fuel as a main engine for propulsion, and the gas injection engine is disposed in a cylinder head and is a gas engine. A main gas fuel injection valve that injects fuel into the cylinder at high pressure, a pilot fuel injection valve that pilot-injects diesel fuel into the cylinder before injection of gas fuel from the main gas fuel injection valve, and high-pressure gas fuel as main gas fuel A main gas fuel supply device for supplying the fuel to the injection valve, a sub gas fuel injection valve for injecting the gas fuel into the cylinder of the gas injection engine, a sub gas fuel supply device for supplying the gas fuel to the sub gas fuel injection valve, A controller for adjusting the engine load by controlling the operation of the gas fuel supply device and the auxiliary gas fuel supply device; In addition, by controlling the operation of the auxiliary gas fuel supply device, before the diesel fuel is pilot injected from the pilot fuel injection valve, all or part of the gas fuel required for combustion is injected from the auxiliary gas fuel injection valve, In the engine operation system of a ship in which the remainder of the gas fuel required for combustion is injected into the cylinder at high pressure from the main gas fuel injection valve after diesel fuel is pilot injected from the pilot fuel injection valve, the controller is a gas injection engine When the engine load is less than a predetermined load, the pre-injection rate, which is the mass ratio of the gas fuel pre-injected from the auxiliary gas fuel injection valve before the pilot fuel injection with respect to all gas fuel required for combustion, is set to 100%. The NOx emission amount of the gas injection engine is suppressed to a predetermined value or less.

  Further, the ship engine operating system of the present invention is a ship engine operating system equipped with a gas injection engine using gas fuel as a main fuel for propulsion, and the gas injection engine is disposed in the cylinder head. A main gas fuel injection valve that injects gas fuel into the cylinder at high pressure, a pilot fuel injection valve that pilot-injects diesel fuel into the cylinder before injection of gas fuel from the main gas fuel injection valve, and a high-pressure gas fuel A main gas fuel supply device that supplies gas fuel to the gas fuel injection valve, a sub gas fuel injection valve that injects gas fuel into the cylinder of the gas injection engine, and a sub gas fuel supply device that supplies gas fuel to the sub gas fuel injection valve And a controller for adjusting the engine load by controlling the operation of the main gas fuel supply device and the sub gas fuel supply device. The controller controls the operation of the auxiliary gas fuel supply device to inject all or part of the gas fuel required for combustion from the auxiliary gas fuel injection valve before the diesel fuel is pilot injected from the pilot fuel injection valve. In addition, in the engine operation system of the ship in which the remainder of the gas fuel required for combustion is injected from the main gas fuel injection valve into the cylinder at high pressure after the diesel fuel is pilot injected from the pilot fuel injection valve, A GPS receiver is further provided, and the controller adjusts the engine load to be equal to or lower than the predetermined load when it is determined that the ship is navigating within the predetermined sea area based on the position information supplied from the GPS receiver, and combustion The pre-injection rate, which is the mass ratio of the gas fuel pre-injected from the auxiliary gas fuel injection valve before the pilot fuel injection for all gas fuel required And 00% inhibit NOX emissions gas injection engine to a predetermined value or less.

  Therefore, the present invention has an excellent effect that it can sufficiently cope with the imminent third-order regulation of NOx without installing a large, complicated and expensive accessory device such as SCR or EGR.

It is a simplification figure showing the ship concerning the engine operation method of the ship of the present invention. FIG. 2 is a simplified diagram showing a gas injection engine of the ship of FIG. 1. FIG. 3 is a system diagram showing a sub gas fuel injection valve and a sub gas fuel supply device of the gas injection engine of FIG. 2. It is a figure which shows the relationship between the pre-injection of the gas injection engine of FIG. 2, pilot injection, and the gas fuel injection after pilot injection. It is a figure explaining the interlock mechanism of the subgas fuel supply apparatus of FIG. FIG. 2 is a simplified diagram showing another embodiment of the gas injection engine of FIG. 1. It is a system diagram which shows the subgas fuel injection valve and subgas fuel supply apparatus of the gas injection engine of FIG. It is a figure which shows the relationship between the pre-injection of the gas injection engine of FIG. 6, pilot injection, and fuel injection after pilot injection. It is a figure explaining the interlock mechanism of the subgas fuel supply apparatus of FIG. It is a flowchart which shows an example of the engine operating system of the ship of this invention. It is a graph which shows the relationship between an engine load and a pre-injection rate as a specific example of the engine operation system of FIG.

  A mode for carrying out the invention of a ship engine operating system according to the present invention will be described in detail with reference to FIGS.

  As shown in FIG. 1, a ship 100 according to the present invention is equipped with a gas injection engine 101 that is operated using a gas fuel such as natural gas as a main fuel. Further, the gas injection engine 101 has an engine controller (controller) 16 that controls the operation of main gas fuel supply devices 8 and 20 and sub gas fuel supply devices 10 and 20 described later to adjust the engine load. it can.

  On the other hand, the ship 100 is equipped with a GPS (Global Positioning System) receiver 102, and the position information detected by the GPS receiver 102 is supplied to the engine controller 16 and used for engine load control and the like. Is done.

  An embodiment of the first invention of the gas injection engine 101 will be described with reference to FIGS. In the first embodiment of the present invention, the pre-injection from the auxiliary gas fuel injection valve is performed at a low pressure from the low-pressure gas fuel injection valve 7 shown in FIG.

  FIG. 2 shows a main part of a gas injection engine 101 using gas fuel such as natural gas as a main fuel as an example. Reference numeral 1 is a cylinder of the gas injection engine 101, 2 is a cylinder head, 3 is a cylinder liner, 4 is a piston that slides up and down in the cylinder liner 1, and 9 is provided in the cylinder head 2 to transfer combustion gas in the cylinder 1 An exhaust valve that exhausts to an exhaust receiver (not shown). The cylinder 1 is an inner cylindrical space formed by the cylinder head 2 and the cylinder liner 3.

  A high pressure gas fuel injection valve (main gas fuel injection valve) 5 for injecting gas fuel into the cylinder 1 at a high pressure into the cylinder head 2, and diesel fuel in the cylinder 1 before injecting gas fuel from the high pressure gas fuel injection valve 5 Pilot fuel injection valves 6 for pilot injection are respectively disposed.

  The high-pressure gas fuel injection valve 5 is supplied with high-pressure gas fuel of, for example, 200 to 300 bar from a high-pressure gas fuel supply device (main gas fuel supply device) 8. A low pressure gas fuel injection valve (sub gas fuel injection valve) 7 for injecting low pressure gas fuel into the cylinder 1 is disposed on the side of the cylinder liner 3. As will be described later, the low-pressure gas fuel injection valve 7 is supplied with low-pressure gas fuel from a low-pressure gas fuel supply device (sub-gas fuel supply device) 10.

  As shown in FIG. 3, the low-pressure gas fuel supply device 10 has the following configuration, for example, and when an abnormality occurs, the supply of gas fuel to the low-pressure gas fuel injection valve 7 is shut off by another system to forcibly An interlock mechanism capable of stopping the injection of gas fuel is provided. Low-pressure gas fuel is supplied from a gas fuel supply source (not shown) to the low-pressure gas fuel injection valve 7 via a hydraulically operated gas fuel on-off valve 12.

The hydraulic pressure supplied from the hydraulic pump 13 is supplied to the gas fuel on-off valve 12 via an electromagnetically operated on-off valve 14 to open and close the on-off valve 12. At the same time, the hydraulic pressure passing through the on-off valve 14 is supplied to the low-pressure gas fuel injection valve 7 via the electromagnetically operated on-off valve 15, and the low-pressure gas fuel injection valve 7 can be opened by this hydraulic pressure.

  The opening and closing of the two electromagnetically operated on / off valves 14 and 15 are electrically controlled by the engine controller 16 of the gas injection engine 101. The interlock mechanism includes an engine controller 16, an electromagnetically operated hydraulic on / off valve 14, and a hydraulically operated gas fuel on / off valve 12.

  During normal operation, the engine controller 16 opens the hydraulic on-off valve 14, thereby opening the gas fuel on-off valve 12 and supplying gas fuel to the low-pressure gas fuel injection valve 7. At the same time, when the engine controller 16 opens the hydraulic on-off valve 15, the hydraulic pressure is supplied to the low-pressure gas fuel injection valve 7 through the two on-off valves 14, 15, and the low-pressure gas fuel injection valve 7 is opened. Let

  Thereby, the low-pressure gas fuel injection valve 7 can inject low-pressure gas fuel supplied from a gas fuel supply source (not shown). Further, when the engine controller 16 closes the hydraulic on-off valve 15, the low-pressure gas fuel injection valve 7 is closed and the injection of the low-pressure gas fuel is stopped.

  Next, the fuel injection method of the above-described gas injection engine 101 will be described. As shown in FIG. 4, for example, diesel fuel is pilot-injected into the cylinder 1 from the pilot fuel injection valve 6 in the vicinity of the top dead center crank angle of 180 °. Further, for example, high pressure gas fuel of 200 to 300 bar, for example, is injected into the cylinder 1 from the high pressure gas fuel injection valve 5 within a certain crank angle range immediately after the end of pilot fuel injection.

  On the other hand, the engine controller 16 sends gas fuel from the low-pressure gas fuel injection valve 7 at a predetermined time within a range of 80 ° to 120 ° after the bottom dead center, for example, at a crank angle, and before the pilot fuel injection. , Pre-injection into the cylinder 1. The pre-injection from the low-pressure gas fuel injection valve 7 is performed at a low pressure of 5 to 15 bar, for example.

  Here, assuming that the mass ratio of the gas fuel pre-injected from the low-pressure gas fuel injection valve 7 before the pilot fuel injection with respect to the total gas fuel necessary for combustion is the pre-injection rate, the engine controller 16 reduces the gas injection engine 101 low. At the time of load, for example, when the load is 50 to 70% (predetermined load) or less, all or part of the gas fuel necessary for combustion, for example, the pre-injection rate is 50% or more, more specifically, the pre-injection rate Is pre-injected into the cylinder 1 with 50-100% or 50-95% gas fuel.

  This is because a relatively large amount of gas fuel can be pre-injected at a low load because the possibility of knocking due to the pre-injection is low in the low load region of the gas injection engine 101. As a result, the ignition by pilot fuel injection and the subsequent increase in gas temperature can be optimized, and the NOx emission can be significantly reduced.

  On the other hand, the engine controller 16 is, for example, when the load of the gas injection engine 101 is high, for example, when the load exceeds 50 to 70%, for example, the pre-injection rate is 50% or less, and more specifically, the pre-injection rate is 10 to 50. % Gas fuel is pre-injected into the cylinder 1.

This is because, when a large amount of gas fuel is pre-injected in a high load region, there is a possibility that knocking may occur due to this pre-injection. Because. Thereby, it is possible to optimize ignition by pilot fuel injection and subsequent gas temperature rise while preventing occurrence of knocking.

  Therefore, the high-pressure gas fuel injected from the high-pressure gas fuel injection valve 5 after the pilot injection becomes the remainder obtained by subtracting the amount of the pre-injected gas fuel from the amount of gas fuel necessary for combustion, and the remainder is the pilot. After fuel injection, it is injected into the cylinder 1 at a high pressure of 200 to 300 bar, for example.

  At this time, the engine controller 16 opens the electromagnetic hydraulic on-off valve 14 of FIG. 3 during normal operation. When the on-off valve 14 is opened, the gas fuel on-off valve 12 is opened by hydraulic pressure, and low-pressure gas fuel is supplied to the low-pressure gas fuel injection valve 7.

  The engine controller 16 opens the hydraulic on-off valve 15 in FIG. 3 at the opening / closing portion of the low-pressure gas fuel injection valve 7 at a predetermined time within the range of, for example, 80 ° to 120 ° after the bottom dead center at the crank angle. Apply hydraulic pressure. As a result, the low pressure gas fuel injection valve 7 is opened and the low pressure gas fuel is injected into the cylinder 1.

  As shown in FIG. 4, when the injection time has elapsed, the engine controller 16 closes the hydraulic open / close valve 15 and closes the open / close portion of the low-pressure gas fuel injection valve 7. Thereby, the pre-injection of the gas fuel from the low-pressure gas fuel injection valve 7 ends.

  The gas fuel injected from the low pressure gas fuel injection valve 7 before the pilot fuel injection is ignited and burned by the combustion of the diesel fuel injected by the pilot injection. Thereby, the gas temperature in the cylinder before the high pressure gas fuel injection is increased as compared with the conventional gas injection engine.

  For this reason, the heat generation in the initial stage of combustion can be brought close to an ideal one, and the thermal efficiency by the combustion of the high-pressure gas fuel performed thereafter can be improved. Further, since all or part of the gas fuel is injected before the pilot injection and ignited by the pilot injection, the combustion becomes so-called lean burn combustion, which can surely reduce the generation of NOx. it can.

  In addition, it is not necessary to inject gaseous fuel at a higher pressure in order to improve thermal efficiency. Furthermore, the amount of the high-pressure gas fuel injected from the high-pressure gas fuel injection valve 5 after the pilot injection is reduced by the pre-injection of the low-pressure gas fuel as compared with the conventional gas injection engine. Therefore, the amount of gas fuel that must be handled as high-pressure gas can be reduced, safety can be improved, and motive energy required to increase the pressure of the gas fuel can be suppressed. As a result, environmental conservation and cost reduction can be achieved.

  In particular, the low-pressure gas fuel injection valve 7 pre-injects the gas fuel into the cylinder 1 at a low pressure of 5 to 15 bar and at a predetermined time within the range of 80 ° to 120 ° after the bottom dead center at the crank angle. Therefore, the ignition by pilot fuel injection and the subsequent gas temperature increase can be optimized.

  On the other hand, the engine controller 16 is shown in FIG. 5 as an interlock mechanism so that fuel is not continuously injected from the low-pressure gas fuel injection valve 7 beyond a certain time when an abnormality occurs even from low-pressure gas fuel. When the window limiter 17 as shown in FIG. 1 is provided, and for some reason, the gas injection from the low pressure gas fuel injection valve 7 is continued or predicted to continue beyond the window limiter 17, The electromagnetic hydraulic on-off valve 14 is closed, and the gas fuel on-off valve 12 is closed.

  Thereby, the supply of the gas fuel to the low pressure gas fuel injection valve 7 is stopped. At the same time, the supply of hydraulic pressure to the low-pressure gas fuel injection valve 7 is also stopped by closing the on-off valve 14, and the open / close portion of the low-pressure gas fuel injection valve 7 is closed, so that gas injection cannot be performed. This ensures safety when an abnormality occurs.

  Next, the fuel injection system according to the second embodiment of the gas injection engine 101 will be described in detail with reference to FIGS. In the second embodiment of the present invention, pre-injection is performed at a high pressure from the high-pressure gas fuel injection valve 18 shown in FIG.

  FIG. 6 shows a main part of the gas injection engine 101 using a gas fuel such as natural gas as a main fuel. The cylinder 1, the cylinder head 2, the cylinder liner 3, the piston 4, and the exhaust valve 9 are the same as those in the first embodiment described above.

  Before injecting gas fuel into the cylinder head 2 from the high pressure gas fuel injection valve (main gas fuel injection valve, auxiliary gas fuel injection valve) 18 for injecting gas fuel into the cylinder at high pressure, diesel A pilot fuel injection valve 6 for pilot-injecting fuel into the cylinder 1 is provided.

  As shown in FIG. 7, a high-pressure gas fuel supply device (main gas fuel supply device, sub-gas fuel supply device) 20 that supplies high-pressure gas fuel to a high-pressure gas fuel injection valve has the following configuration, for example. It has an interlocking mechanism that can shut off the gas fuel injection by forcibly stopping the supply of the gas fuel to the high-pressure gas fuel injection valve 18 when another abnormality occurs.

  High-pressure gas fuel is supplied to a high-pressure gas fuel injection valve 18 from a gas fuel supply source (not shown) through an accumulator 21 and a hydraulically operated gas fuel on-off valve 22. The hydraulic pressure supplied from the hydraulic pump 23 is supplied to the gas fuel on-off valve 22 via an electromagnetically operated on-off valve 24 to open and close the on-off valve 22.

  At the same time, the hydraulic pressure that has passed through the on-off valve 24 is supplied to the high-pressure gas fuel injection valve 18 via the electromagnetically operated on-off valve 25, and the high-pressure gas fuel injection valve 18 can be opened by the supply of this hydraulic pressure. .

  The two electromagnetically operated on / off valves 24 and 25 are electrically controlled by an engine controller 26 of the gas injection engine 101. The interlock mechanism includes an engine controller 26, an electromagnetically operated hydraulic on / off valve 24, and a hydraulically operated gas fuel on / off valve 22.

  Next, the fuel injection method of the above-described gas injection engine 101 will be described. As shown in FIG. 8, for example, diesel fuel is pilot-injected into the cylinder 1 from the pilot fuel injection valve 6 in the vicinity of the top dead center crank angle of 180 °. Further, high-pressure gas fuel of 200 to 300 bar, for example, is injected into the cylinder 1 from the high-pressure gas fuel injection valve 18 in a certain crank angle range immediately after the end of pilot fuel injection.

  On the other hand, the engine controller 26 sends gas fuel from the high-pressure gas fuel injection valve 18 at a predetermined time within the range of 120 ° to 160 ° after the bottom dead center at the crank angle, and from the pilot fuel injection valve 6. Prior to pilot fuel injection, pre-injection into the cylinder 1 is performed. The pre-injection from the high-pressure gas fuel injection valve 18 is performed at a high pressure of 200 to 300 bar, for example.

Here, the mass ratio of the gas fuel pre-injected from the high-pressure gas fuel injection valve 18 before the pilot fuel injection with respect to the total gas fuel required for combustion is referred to as a pre-injection rate.
When the load of the gas injection engine 101 is low, for example, when the load is 50 to 70% (predetermined load) or less, the engine controller 16 has all or part of gas fuel necessary for combustion, for example, a pre-injection rate of 50. More specifically, gas fuel having a pre-injection rate of 50 to 100% or 50 to 95% is pre-injected into the cylinder 1.

  This is because a relatively large amount of gas fuel can be pre-injected at low load because the possibility of knocking due to pre-injection is low in the low load region. Thereby, the ignition by pilot fuel injection and the subsequent gas temperature rise can be optimized.

  On the other hand, the engine controller 16 is, for example, when the load of the gas injection engine 101 is high, for example, when the load exceeds 50 to 70%, for example, the pre-injection rate is 50% or less. ~ 50% of gas fuel is pre-injected into the cylinder 1.

  This is because, when a large amount of gas fuel is pre-injected in a high load region, there is a possibility that knocking may occur due to this pre-injection, so it is necessary to keep the pre-injection amount of gas fuel within a certain range at high load Because. Thereby, it is possible to optimize ignition by pilot fuel injection and subsequent gas temperature rise while preventing occurrence of knocking.

  Further, although the ratio may be small, at least a fixed amount of pre-injection is performed, so that the amount of NOx emission is surely reduced as compared with the case where all of the gas fuel is injected after pilot fuel injection as in the prior art.

  Further, the high-pressure gas fuel injected from the high-pressure gas fuel injection valve 5 after the pilot injection becomes a balance obtained by subtracting the amount of the pre-injected gas fuel from the amount of gas fuel necessary for combustion, and the remaining portion is the pilot fuel. After the injection, the high pressure gas fuel injection valve 18 is injected into the cylinder 1 at a high pressure of, for example, 200 to 300 bar.

  At this time, the engine controller 26 opens the electromagnetic hydraulic on-off valve 24 of FIG. 7 during normal operation. When the on-off valve 24 is opened, the gas fuel on-off valve 22 is opened by hydraulic pressure, and the gas fuel is supplied to the high-pressure gas fuel injection valve 18.

  When the crank angle reaches a predetermined time within the range of 120 ° to 160 ° after bottom dead center, the engine controller 26 opens the hydraulic on-off valve 25 in FIG. multiply. As a result, the high-pressure gas fuel injection valve 18 is opened to inject high-pressure gas fuel into the cylinder 1. As shown in FIG. 8, when the injection time has elapsed, the engine controller 26 closes the hydraulic on-off valve 25 and ends the pre-injection of gas fuel from the high-pressure gas fuel injection valve 18.

  The gas fuel injected from the high-pressure gas fuel injection valve 18 before the pilot fuel injection is ignited and burned by the combustion of the pilot-injected diesel fuel. As a result, the gas temperature in the cylinder before the high-pressure main gas fuel injection is increased as compared with the conventional gas injection engine.

  For this reason, the heat generation in the initial stage of combustion can be brought close to an ideal one, and the thermal efficiency by the combustion of the high-pressure main gas fuel performed thereafter can be improved. Moreover, it is not necessary to inject the gas fuel at a higher pressure in order to improve the thermal efficiency.

Further, since all or part of the gas fuel is injected before the pilot injection and ignited by the pilot injection, the combustion becomes so-called lean burn combustion, which can surely reduce the generation of NOx. it can. As a result, environmental conservation and cost reduction can be achieved.

  In particular, in the fuel injection system of the present gas injection engine, the pre-injection from the high-pressure gas fuel injection valve 18 is performed at a high pressure of 200 to 300 bar and within a range of 120 ° to 160 ° after the bottom dead center at the crank angle. It is performed at a predetermined time. Therefore, the ignition by the pilot fuel injection and the subsequent gas temperature increase can be optimized.

  On the other hand, the engine controller 26 has a window limiter as an interlock mechanism so that the fuel is not continuously injected from the high-pressure gas fuel injection valve 18 for a certain time when an abnormality occurs for safety reasons. When the gas injection from the high-pressure gas fuel injection valve 18 has continued or is predicted to exceed the window limiter, the electromagnetic hydraulic on-off valve 24 is closed, and the gas fuel on-off valve is closed. 22 is closed.

  Thereby, the supply of the gas fuel to the high-pressure gas fuel injection valve 18 is stopped. Moreover, the supply of hydraulic pressure to the high-pressure gas fuel injection valve 18 is stopped by closing the on-off valve 24, and the opening / closing portion of the high-pressure gas fuel injection valve 18 is closed, so that gas injection cannot be performed. This ensures safety when an abnormality occurs.

  Further, as shown in FIG. 9, the window limiter 27 has a constant continuous time between, for example, pre-injection before pilot fuel injection from the high-pressure gas fuel injection valve 18 and injection of high-pressure gas fuel after pilot fuel injection. It can also be set not to exceed the time.

  Next, an example of an engine operation method for a ship equipped with the gas injection engine 101 will be described with reference to FIGS.

  As shown in FIG. 10, the controller 16 is based on the position information supplied from the GPS receiver 102 of FIG. 1 (step S2), and the marine area (predetermined to which the third regulation value of NOx emission amount is applied to the ship. If it is determined that the vehicle is navigating the sea area) or will be sailing from now on, the engine load of the gas injection engine 101 is adjusted to a load within a range of 50 to 70%, for example, 60% or less (step S2). , S4, S6).

  Here, the threshold between the low load region and the high load region of the gas injection engine 101 is set within the range of 50 to 70% of the load. If the load is less than 50%, the navigation of the ship is hindered. If the load exceeds 70%, there is a concern about the occurrence of knocking that is occasionally observed in the lean burn engine, and the ignition by the pilot fuel injection and the subsequent gas temperature increase are optimized. Because there is a fear that it cannot be done.

  At this time, the engine controller 16 pre-injects all the gas fuel necessary for combustion into the cylinder 1 before the pilot fuel injection from the pilot fuel injection valve 6 (step S8). That is, the pre-injection rate, which is the mass ratio of the gas fuel pre-injected from the auxiliary gas fuel injection valve, before the pilot fuel injection with respect to all gas fuel necessary for combustion is set to 100%.

  First, gas fuels such as natural gas have much lower sulfur content than diesel oil, etc., so all the current and soon-to-be-applied SOX regulations and particulate matter (PM) regulations It can be cleared.

Further, the gas fuel injected from the auxiliary gas fuel injection valves 7 and 18 before the pilot fuel injection is ignited and burned by the combustion of the diesel fuel injected by the pilot injection. As a result, the gas temperature in the cylinder 1 before the high-pressure injection of the gas fuel from the main gas fuel injection valves 5 and 18 is higher than that of the conventional gas injection engine.

  For this reason, the heat generation in the initial stage of combustion can be brought close to an ideal one, and the thermal efficiency by combustion of the gas fuel can be improved without further increasing the pressure of the gas fuel. In particular, if all of the gas fuel is injected and ignited before pilot fuel injection, the combustion becomes lean burn combustion similar to lean premixed combustion in a diesel engine, which greatly increases the generation of NOx. Can be reduced.

  For this reason, it is possible to suppress the NOx emission amount to 3.4 g / kWh or less, which is the third regulation value for an engine whose engine speed is less than 130 rpm. Further, the premixed gas engine has a characteristic that the occurrence of knocking due to gas injection is small in a low load region of 60% or less. Therefore, the possibility of knocking is very low.

  By the way, the sea area to which the above-mentioned third regulation value of NOx emission is applied is currently limited to the sea area within 200 nautical miles of the US and Canadian coasts and the US caribbean sea area. Even if it is limited to 60% or less, there is no particular problem in the operation of the ship.

  On the other hand, for example, in the sea area where the regulation value before the third regulation, which is significantly looser than the third regulation value of NOx emissions, is applied, the controller 16 determines the engine load of the gas injection engine 101 as follows. As shown in FIG. 11, it is increased to exceed 60%, for example. As a result, full speed travel is possible (steps S4 and S10).

  Here, the regulation value before the third regulation of NOx emission and the next severe regulation value after the third regulation value is the second regulation value, and this second regulation value is the engine speed. The NOx emission amount for an engine having a number of less than 130 rpm is 14.4 g / kWh or less.

  When the engine load exceeds 60%, the pre-injection rate is 50% or less, more specifically, gas fuel having a pre-injection rate of 10 to 50% is pre-injected into the cylinder 1 (step S14). . If this high engine load is over 60%, it is limited to the sea area where the regulation value before the third regulation of NOx emissions is applied. All current and upcoming regulatory values, including regulatory values, can be cleared.

  Further, it is known that a premixed gas engine has a high possibility of occurrence of knocking due to gas injection in a high load region. Therefore, it is necessary to keep the pre-injection rate within a certain range at a high load. In particular, by setting the pre-injection rate to 50% or less, ignition by pilot fuel injection and the subsequent gas temperature are prevented while preventing knocking. The increase can be optimized and NOx emissions can be reduced.

  As shown in FIG. 11, for example, when the engine load is 60%, the pre-injection rate is about 50%, and when the engine load is 100%, the pre-injection rate is about 30%. Thus, the gas fuel can be pre-injected into the cylinder.

  On the other hand, in the sea area where the regulation value before the third regulation of NOx emission is applied, the pre-injection rate becomes 50 to 100% when the engine load is low load operation of 60% or less. Gas fuel is pre-injected into the cylinder 1 (steps S4, 10, 12).

  As described above, by setting the pre-injection rate to 50 to 100%, the gas fuel injected from the auxiliary gas fuel injection valves 7 and 18 before the pilot fuel injection is reduced against the combustion of the gas fuel of the gas injection engine 101. Will be in an optimal state.

  For this reason, the heat generation in the initial stage of combustion can be brought close to an ideal one, and the thermal efficiency by combustion of the gas fuel can be improved without further increasing the pressure of the gas fuel. Further, the combustion becomes lean burn combustion similar to the lean premixed combustion in the diesel engine, so that the generation of NOx can be surely reduced below the regulation value before the third regulation of the NOx emission amount.

  As shown in FIG. 11, for example, when the engine load increases, the pre-injection rate is reduced to 100% when the engine load is 0 to 45%, and the pre-injection rate is lowered to about 67% at a time when the engine load is 45%. Thereafter, gas fuel is introduced into the cylinder from the low-pressure gas fuel injection valve 7 or the high-pressure gas fuel injection valve 18 in such a manner that the pre-injection rate is reduced gradually at an equal rate so that the engine injection is 50%. Pre-injection can be performed.

  On the other hand, when the engine load is reduced, the pre-injection rate is increased to 100% when the engine load is 40%. Thus, between the load point that decreases from 100% to a pre-injection rate of less than 100% when the engine load increases, and the load point that increases from less than 100% to a pre-injection rate of 100% when the engine load decreases. By providing a certain hysteresis, the control regarding the pre-injection of the gas fuel is prevented from becoming unstable.

  Note that the above-described ship engine operation system is merely an example, and various modifications can be made.

1 Cylinder 2 Cylinder Head 3 Cylinder Liner 4 Piston 5 High Pressure Gas Fuel Injection Valve (Main Gas Fuel Injection Valve)
6 Pilot fuel injection valve 7 Low pressure gas fuel injection valve (sub gas fuel injection valve)
8 High-pressure gas fuel supply device (main gas fuel supply device)
9 Exhaust valve 10 Low-pressure gas fuel supply device (sub-gas fuel supply device)
12 On-off valve 13 Hydraulic pump 14 On-off valve 15 On-off valve 16 Engine controller (controller)
17 Window limiter 18 High pressure gas fuel injection valve (main gas fuel injection valve, auxiliary gas fuel injection valve)
20 High-pressure gas fuel supply device (main gas fuel supply device, auxiliary gas fuel supply device)
21 accumulator 22 on-off valve 23 hydraulic pump 24 on-off valve 25 on-off valve 26 engine controller 27 window limiter 100 ship 101 gas injection engine 102 GPS receiver

Claims (7)

This is an engine operation system of a ship (100) equipped with a gas injection engine (101) using gas fuel as a main fuel for propulsion, and the gas injection engine is disposed in a cylinder head (2) and gas A main gas fuel injection valve (5, 18) for injecting fuel into the cylinder (1) at a high pressure, and a pilot fuel for pilot injection of diesel fuel into the cylinder before injection of the gas fuel from the main gas fuel injection valve An injection valve (6), a main gas fuel supply device (8, 20) for supplying high-pressure gas fuel to the main gas fuel injection valve, and a secondary gas fuel for injecting the gas fuel into the cylinder of the gas injection engine An injection valve (7, 18), an auxiliary gas fuel supply device (10, 20) for supplying the gas fuel to the auxiliary gas fuel injection valve, and the main gas A fuel supply device and a controller (16) for controlling the operation of the auxiliary gas fuel supply device to adjust the engine load, and the controller controls the operation of the auxiliary gas fuel supply device to control the pilot fuel injection valve. Before the diesel fuel is injected from the pilot fuel, all or part of the gas fuel required for combustion is injected into the cylinder from the auxiliary gas fuel injection valve, and the diesel fuel is piloted from the pilot fuel injection valve. In the engine operation system of the ship in which the remaining part of the gas fuel required for combustion from the main gas fuel injection valve is injected into the cylinder at a high pressure after being injected,
The controller is configured such that when the engine load of the gas injection engine is equal to or lower than a predetermined load, the mass of the gas fuel pre-injected from the auxiliary gas fuel injection valve before the pilot fuel injection for all gas fuels required for combustion A marine engine operating system characterized in that the pre-injection rate, which is a ratio, is set to 100%, and the NOx emission amount of the gas injection engine is suppressed to a predetermined value or less.   The ship according to claim 1, wherein the controller (16) sets the pre-injection rate to 50% or less when the engine load of the gas injection engine (101) exceeds the predetermined load. Engine operation system. This is an engine operation system of a ship (100) equipped with a gas injection engine (101) using gas fuel as a main fuel for propulsion, and the gas injection engine is disposed in a cylinder head (2) and gas A main gas fuel injection valve (5, 18) for injecting fuel into the cylinder (1) at a high pressure, and a pilot fuel for pilot injection of diesel fuel into the cylinder before injection of the gas fuel from the main gas fuel injection valve An injection valve (6), a main gas fuel supply device (8, 20) for supplying high-pressure gas fuel to the main gas fuel injection valve, and a secondary gas fuel for injecting the gas fuel into the cylinder of the gas injection engine An injection valve (7, 18), an auxiliary gas fuel supply device (10, 20) for supplying the gas fuel to the auxiliary gas fuel injection valve, and the main gas A fuel supply device and a controller (16) for controlling the operation of the auxiliary gas fuel supply device to adjust the engine load, and the controller controls the operation of the auxiliary gas fuel supply device to control the auxiliary gas fuel injection. All or part of the gas fuel required for combustion can be injected before diesel fuel is pilot-injected from the pilot fuel injection valve from the valve, and the pilot fuel injection from the main gas fuel injection valve In the engine operation system of a ship that can inject the remainder of the gas fuel required for combustion after pilot injection of diesel fuel from a valve into the cylinder at high pressure,
The ship (100) further includes a GPS receiver (102), and the controller (16) determines that the ship is navigating in a predetermined sea area based on position information supplied from the GPS receiver. In this case, the engine load is adjusted to a predetermined load or less, and the pre-injection is a mass ratio of the gas fuel pre-injected from the auxiliary gas fuel injection valve before the pilot fuel injection with respect to all gas fuel necessary for combustion. A ship engine operating system characterized in that the NOx emission amount of the gas injection engine is suppressed to a predetermined value or less by setting the rate to 100%.   The controller (16) is a case where it is determined that the ship is navigating outside a predetermined sea area based on position information supplied from the GPS receiver, and the engine load is equal to or less than the predetermined load 4. The ship engine operating system according to claim 3, wherein the pre-injection rate is 50% or more.   The controller (16) sets the pre-injection rate to 100% at a low load immediately after the start of the gas injection engine (101) and increases the pre-injection rate to 100% before the engine load increases to the predetermined load. The load point for decreasing the pre-injection rate from 100% to less than 100% when the load is increased is gradually increased from less than 100% to the pre-injection rate of 100% when the load is decreased. The ship engine operating system according to claim 4, wherein the ship operating system is high.   When the controller (16) determines that the ship is navigating outside a predetermined sea area based on position information supplied from the GPS receiver, and the engine load exceeds the predetermined load The ship engine operating system according to any one of claims 3 to 5, wherein the pre-injection rate is 50% or less.   The ship engine operating system according to any one of claims 1 to 6, wherein the predetermined load of the engine load is set within a range of load (50 to 70)%. .

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