JP6038225B2 - Gas fired engine - Google Patents

Description

  The present invention relates to a gas-fired engine that is applied to, for example, a main engine of a ship, a generator drive engine, and the like and is operated using gas fuel such as natural gas as fuel.

Conventionally, there are many diesel engines that operate using natural gas vaporized from liquefied natural gas (hereinafter referred to as “LNG”) as fuel. In recent years, measures have been taken to improve the environmental emission performance of existing oil-fueled low-speed diesel main engines. As such, a high-pressure gas injection type low-speed two-stroke diesel engine (hereinafter referred to as “SSD-GI”) has attracted attention. This SSD-GI is an engine having higher thermal efficiency and higher response than conventional LNG-utilizing heat engines (for example, steam turbines) and capable of outputting at low speed, and is directly connected to a propeller. Can be driven.
However, in the case of SSD-GI, which uses natural gas as fuel, unlike high-performance diesel diesel engines, high-pressure injection technology that supplies natural gas at high pressure (up to about 150 to 300 bar) into the combustion chamber has matured. No technology has been established yet for LNG fuel supply.

Conventionally, when SSD-GI was regarded as a main engine candidate for an LNG ship, boil-off gas (hereinafter referred to as “BOG”) at approximately atmospheric pressure is compressed by a multistage gas compressor, and further, A method of cooling the BOG after compression and using it as an engine fuel has been studied. However, the method of compressing and cooling BOG has been regarded as a drawback because it requires large-scale equipment and consumes a large amount of power.
As a propulsion engine for an LNG carrier, for example, as described in the following Patent Document 1 (see FIG. 7 and the like), the BOG in the gas tank is compressed in two stages by a low-pressure and high-pressure compressor and placed in the engine compartment. There is something to introduce.

  On the other hand, in the recent days when a BOG reliquefaction system has been realized on an LNG ship, it is possible to store the liquefied BOG without using it as fuel. For this reason, from the viewpoint of effective use of BOG, efforts have been made on the method of using BOG as fuel in conventional LNG ships, but there is no obstacle to this point in using LNG as the main fuel of the main engine. ing. Further, when LNG is used as a fuel in a ship other than the LNG ship, the BOG treatment is unnecessary by using a pressurized LNG tank.

Against this background, in recent ships, the use of LNG having good environmental emission performance as fuel for main engines, etc. has attracted attention, and various research and development related to LNG use methods and the like have been made. It is becoming active.
As a method for supplying fuel by injecting high-pressure natural gas, it is conceivable to heat and vaporize LNG after increasing its pressure. Such LNG is generally increased in pressure by using a reciprocating pump. Since this reciprocating pump has a rotational speed of about 300 rpm, the reciprocating pump has a considerably low speed as compared with 1800 to 3600 rpm which is a rotational speed of a general electric motor speed. For this reason, when the reciprocating pump is driven by an electric motor, a mechanism for decelerating to the rotational speed of the reciprocating pump is required.

As a general speed reduction mechanism used for the operation of the reciprocating pump, a geared system and a pulley system are known. The geared speed reduction mechanism is a speed reduction mechanism that combines a plurality of gears having different numbers of teeth, and the pulley speed reduction mechanism has a structure that rotates large and small wheels connected by a V-belt.
In the liquefied gas regasification plant, for example, as disclosed in Patent Document 2 below, the pressure of the liquefied gas taken out from the storage tank is increased by a pump in a liquid state to increase the pressure. Things have been done.

  Further, in recent marine diesel engines, electronic control engines effective for environmental measures such as reduction of nitrogen oxides have been developed in response to the tightening of exhaust gas regulations for global marine engines. This electronically controlled engine is an electronic control of at least part of the fuel injection system, exhaust valve system, starter system and cylinder lubrication system driven by a conventional camshaft. Is used to drive each device of the engine.

Japanese Patent Laid-Open No. 9-209788 JP 2009-204026 A

  As described above, in recent ships, although LNG is gaining attention as a fuel for the main engine, a high-pressure gas supply technique for injecting natural gas into the combustion chamber at a high pressure has not been established. In order to inject natural gas as high-pressure fuel as an engine fuel, it is considered that the pressure of LNG needs to be increased by a reciprocating pump, and the following problems regarding drive control of the reciprocating pump have been pointed out. That is, when an electric motor is used as a driving source of the reciprocating pump and an operation method in which the motor is decelerated to the rotational speed of the reciprocating pump via a speed reducing mechanism is employed, the following problems occur with respect to the speed reducing mechanism and the electric motor.

The first problem relates to a mechanical speed reduction mechanism necessary for driving the electric motor of the reciprocating pump.
Specifically, the geared type speed reduction mechanism is expected to damage the gear tooth surface and tooth root due to torque fluctuation from the reciprocating pump side. Consideration should be given to couplings such as elastic joints and inertia wheels for buffering.
On the other hand, the pulley type speed reduction mechanism has the advantage that the torque fluctuation peculiar to the piston pump can be mitigated by the slip of the belt, but the belt is a consumable that needs to be replaced in a short period. This method is not suitable for continuous use. In addition, since the pulley type deceleration mechanism is concerned about the occurrence of sparks at the exposed high-speed contact portion, installation in a gas hazardous area is not preferable for safety.

The second problem relates to the electric motor that drives the reciprocating pump.
More specifically, when the electric motor is decelerated to the rotational speed of the reciprocating pump by the reduction mechanism, a frequency control mechanism (inverter) is required regardless of which of the above-described geared method and pulley method. However, since the frequency control mechanism of an electric motor has difficulty in accuracy at low frequencies, it is disadvantageous when the control range is wide and high-precision control is required even in a considerably low speed rotation region.

In addition, when installing electrical equipment such as electric motors in gas hazardous areas, there are restrictions on the choice of usable equipment, so there are many restrictions on installing motor-driven reciprocating pumps in gas hazardous areas. It will be.
The present invention has been made in order to solve the above-described problems. The object of the present invention is to provide a fuel gas (for example, natural gas) in a combustion chamber such as an electronically controlled gas injection type low-speed two-stroke diesel engine. A gas-fired engine capable of supplying a liquefied fuel gas (for example, LNG) using a reciprocating pump that can be easily placed in a gas hazardous area in an injection technology applied to a gas injection diesel engine that supplies gas) There is to do.

In order to solve the above problems, the present invention employs the following means.
A gas-fired engine according to a first aspect of the present invention includes an electronic control unit that drives an engine by controlling hydraulic oil with a controller and a solenoid valve, and a gas fuel supply device that boosts and supplies liquefied gas. A gas-fired engine of a gas-injected diesel engine, wherein the gas fuel supply device is driven by a hydraulic motor and boosts the introduced liquefied gas to a desired pressure and discharges it, and the hydraulic oil is supplied A hydraulic introduction system that introduces a part of the hydraulic oil from the hydraulic system to supply and drive the hydraulic motor, and a control unit that adjusts the rotational speed of the hydraulic motor to keep the gas fuel outlet pressure constant. wherein the hydraulic motor and the reciprocating pump is installed in the gas hazardous area, the control unit, the rotational speed of the hydraulic motor, subjecting the working oil to the hydraulic system It is characterized in that the rotational speed be controlled by adjusting the discharge amount of the hydraulic pump.

  According to such a gas-fired engine of the first aspect, the gas fuel supply device is supplied with hydraulic oil and a reciprocating pump that is driven by a hydraulic motor to increase the pressure of the introduced liquefied gas to a desired pressure and discharge it. A hydraulic introduction system that introduces a part of hydraulic oil from a hydraulic system that supplies and drives the hydraulic motor, and a control unit that adjusts the rotational speed of the hydraulic motor to keep the gas fuel outlet pressure of the heating device constant. Therefore, it is possible to minimize the use of new additional equipment by effectively using the hydraulic fluid of the electronic control unit, and to increase the pressure of the liquefied gas by a reciprocating pump driven by a hydraulic motor.

  In such a gas-fired engine, the engine speed increases as the engine load increases, so that the discharge amount and hydraulic pressure of the engine-driven hydraulic pump that supplies hydraulic oil to the hydraulic system increase. Therefore, when the consumption amount of fuel (vaporized liquefied gas) increases, the hydraulic fluid supplied to the hydraulic system is a suitable hydraulic source for the reciprocating pump for boosting the liquefied gas, which also increases the required flow rate and pressure.

  The rotational speed of the hydraulic motor that drives the reciprocating pump is adjusted by adjusting the discharge rate of the hydraulic pump that supplies hydraulic oil to the hydraulic system, so there is no need to add a mechanical speed reduction mechanism or motor speed control. It becomes unnecessary.

  The gas cooking engine according to the second aspect of the present invention includes an electronic control unit that drives the engine by controlling hydraulic oil with a controller and a solenoid valve, and a gas fuel supply device that boosts and supplies liquefied gas. A gas-fired engine of a gas-injected diesel engine, wherein the gas fuel supply device is driven by a hydraulic motor and boosts the introduced liquefied gas to a desired pressure and discharges it, and the hydraulic oil is supplied A hydraulic introduction system that introduces a part of the hydraulic oil from the hydraulic system to supply and drive the hydraulic motor, and a control unit that adjusts the rotational speed of the hydraulic motor to keep the gas fuel outlet pressure constant. The hydraulic motor, the reciprocating pump, and the hydraulic pump that supplies the hydraulic fluid to the hydraulic system are connected to each other by hydraulic piping. In the hydraulic motor and the reciprocating pump, characterized in that it is installed in the gas hazardous area.

  According to such a gas-fired engine of the second aspect, the reciprocating pump driven by the hydraulic motor and the hydraulic pump unit that supplies hydraulic pressure to the hydraulic motor are connected separately by hydraulic piping. Thus, a reciprocating pump without an electric device or a speed reduction mechanism can be easily installed in a gas hazardous area.

  According to the gas-fired engine of the present invention described above, in a gas injection diesel engine that supplies fuel gas (for example, natural gas) into a combustion chamber, such as an electronically controlled gas injection type low-speed two-stroke diesel engine. The fuel liquefied gas (for example, LNG) can be supplied by using a reciprocating pump driven by a hydraulic pump that can be easily disposed in the gas danger zone.

  And if the hydraulic pressure is supplied from the electronic control unit on the engine side, there is no need to install a new hydraulic unit that supplies hydraulic pressure to the hydraulic motor for driving the reciprocating pump. In particular, in a limited ship, it is possible to effectively use the ship space such as increasing the load space.

1 is a system diagram showing a first embodiment as an embodiment of a gas-fired engine according to the present invention. It is a systematic diagram showing a second embodiment as an embodiment of a gas-fired engine according to the present invention. It is a systematic diagram which shows 3rd Embodiment as one Embodiment of the gas-fired engine which concerns on this invention. It is explanatory drawing which shows the pump load and recirculation control valve (RCV) opening degree of a reciprocating pump on a vertical axis | shaft by making a horizontal axis into an operating point (OP).

Hereinafter, an embodiment of a gas-fired engine according to the present invention will be described with reference to the drawings.
<First Embodiment>
The gas-fired engine 1 of the embodiment shown in FIG. 1 includes an electronic control unit 60 that drives the engine by controlling high-pressure hydraulic oil with a controller and a solenoid valve, and a high-pressure liquefied gas that is injected into the combustion chamber of the engine. This is a high-pressure gas injection diesel engine equipped with a gas fuel supply device 10 that is pressurized and supplied to the engine.
The electronic control unit 60 to be described later is an electronic control of the conventional camshaft drive for at least a part of the fuel injection system, exhaust valve system, start system, and cylinder lubrication system of the gas-fired engine 1. .

The illustrated gas-fired engine 1 is provided with a gas fuel supply device 10 having a “high-pressure mode” that injects and supplies fuel gas obtained by vaporizing liquefied gas into a combustion chamber of a high-pressure gas injection diesel engine. As a specific example of the gas-fired engine 1 according to the present embodiment, there is a high-pressure gas injection diesel engine, for example, a high-pressure gas injection low-speed two-stroke diesel engine (hereinafter referred to as “SSD-GI”).
In the following description, the liquefied gas is liquefied natural gas (hereinafter referred to as “LNG”), and the natural gas vaporized by LNG is used as fuel gas. The present invention is also applicable to an engine using liquefied gas such as gas (LPG) as fuel.

  The gas fuel supply device 10 includes an LNG fuel system that injects and supplies natural gas that has been vaporized after the LNG has been boosted by the reciprocating pump 20 into a combustion chamber of a high-pressure gas injection engine, and a hydraulic pressure that drives the reciprocating pump 20. A hydraulic system that supplies hydraulic pressure to the motor 50 and a control unit (not shown) that controls the hydraulic motor 50 and the like are provided. In the illustrated configuration example, one set of LNG fuel system and hydraulic system is shown, but a plurality of installations may be connected to each other, and the present invention is not limited to this.

The LNG fuel system includes a reciprocating pump 20 driven by a hydraulic motor 50. The reciprocating pump 20 is a pump that introduces LNG in a substantially atmospheric pressure state, raises the pressure to a desired pressure, and discharges the pressure.
The LNG supply pipe 22 connected to the discharge side of the reciprocating pump 20 includes a heating device 30 and an engine inlet gas pressure reducing valve (hereinafter referred to as “gas pressure reducing valve”) 40 arranged in order from the pump side.

The heating device 30 is a device that heats and vaporizes the pressurized LNG supplied from the reciprocating pump 20. That is, the high-pressure LNG that has flowed into the heating device 30 is heated in the device, and flows out as natural gas vaporized from the LNG.
A pressure sensor (not shown) is provided in the vicinity of the outlet of the heating device 30, and the natural gas outlet pressure PV detected by the pressure sensor is input to the control unit as the gas fuel outlet pressure. This control unit adjusts the rotational speed of a hydraulic motor 50, which will be described later, in order to maintain the natural gas outlet pressure PV at a predetermined constant pressure value. In addition, this control part may be comprised integrally with the control part of the electronic control unit 60 mentioned later.

  The natural gas supplied from the heating device 30 is adjusted to a desired pressure by the gas pressure reducing valve 40 and then injected and supplied into the high-pressure combustion chamber. That is, the natural gas injection (supply) pressure adjusted by the gas pressure reducing valve 40 is compressed by the piston and injected into the combustion chamber in a high-pressure state, so it is necessary to set the pressure higher than the pressure in the combustion chamber. Such an operation mode in which natural gas is injected into the combustion chamber at a high pressure is referred to as a “high pressure mode”. In the case of SSD-GI, the injection pressure of natural gas in the high pressure mode is approximately 150 to 300 bar.

  In addition to the above-described “high pressure mode”, the gas pressure reducing valve 40 has a “low pressure mode” for supplying natural gas of gas fuel as fuel for a gas spark type Otto cycle engine. This “low pressure mode” is used, for example, when gas fuel is supplied to a power generation engine or the like that covers inboard power, and has a lower pressure than the “high pressure mode”.

  The LNG supply pipe 22 includes a recirculation line 23 that branches from the upstream side of the heating device 30. The recirculation line 23 is a piping system that branches the LNG boosted by the reciprocating pump 20 from the upstream side of the heating device 30 and flows it to the suction drum 24. A circulation control valve 25 is provided. The LNG introduction pipe 21 connected to the suction drum 24 is connected to an LNG tank or the like (not shown).

By providing such a recirculation line 23, when the LNG flow rate is throttled in a low speed region where the rotation speed of the hydraulic motor 50 cannot be controlled or in an emergency, the recirculation line 23 flows by adjusting the opening degree of the recirculation control valve 25. It becomes possible to respond by controlling the LNG recirculation flow rate.
More specifically, as shown in the explanatory diagram of FIG. 4, for example, in a low speed region where the pump load is small, the opening of the recirculation control valve 25 is increased to ensure the recirculation flow rate, that is, the operating point where the pump load is small. In OP, the total flow rate of LNG flowing through the reciprocating pump 20 is secured by increasing the recirculation flow rate, and is maintained in the rotation speed region where the hydraulic motor 50 can be controlled. When the amount of LNG is squeezed urgently, the recirculation flow rate for bypassing the heating device 30 is increased by increasing the opening degree of the recirculation control valve 25 and the supply amount to the heating device 30 may be limited.

The suction drum 24 is an LNG container that collects the LNG branched and introduced from the LNG supply pipe 22 and returns it to the recirculation suction unit of the reciprocating pump 20. The recirculation flow rate of LNG introduced into the recirculation line 23 is adjusted by the recirculation control valve 25 that operates based on the control signal of the operating point OP output from the control unit. The control signal for this operating point OP is an opening signal that defines the operating point output by the control unit based on, for example, a set point SP given by the engine speed and a natural gas outlet pressure PV detected by the pressure sensor. is there.
As the set point SP in this case, a variable value that provides a pressure value with high controllability of the gas pressure reducing valve 40, such as the engine speed described above, may be adopted, or the set point SP may be a fixed value. It is good.

  In this case, the hydraulic system introduces a part of the hydraulic pressure held by the electronic control unit 60 and supplies it to the hydraulic motor 50 that drives the reciprocating pump 20. That is, a hydraulic introduction system 51 that introduces a part of high-pressure hydraulic oil from the hydraulic system 61 of the electronic control unit 60 and supplies and drives the hydraulic motor 50, and the high-pressure hydraulic oil used to drive the hydraulic motor 50 is supplied to the hydraulic system 61. And a hydraulic pressure return system 52 for returning to.

The hydraulic system 61 of the electronic control unit 60 uses part of the engine lubricating oil stored in the crankcase 62 as high-pressure hydraulic hydraulic fluid.
The engine lubricating oil in the crankcase 62 is supplied to the filter unit 65 by an electric lubricating oil pump 64 provided in the lubricating oil line 63. After the foreign matter is removed by the filter unit 65, the engine lubricating oil is supplied to the hydraulic system 61 with high-pressure hydraulic oil that has been boosted by the engine drive pump 66 or the electric pump 67. In this case, the electric pump 67 described above is necessary when the engine is started, and the hydraulic pressure supply from the engine drive pump 66 is mainly used in the normal operation after the engine is started.
A switching valve block 68 is provided between the engine drive pump 66 driven by the gas-fired engine 1 and the hydraulic system 61 to change the pump suction direction and the pump discharge direction when the gas-fired engine 1 is reversely rotated. .

The hydraulic introduction system 51 is a piping system that branches from the hydraulic system 61 on the upstream side of the electronic control unit 60 and supplies a part of the high-pressure hydraulic oil to the hydraulic motor 50.
The hydraulic pressure return system 52 is a piping system that returns the high-pressure hydraulic oil used for driving the hydraulic motor 50 to the hydraulic system 61. The hydraulic pressure return system 52 is provided with a sub-storage tank 53 for temporarily storing high-pressure hydraulic oil used for driving the hydraulic motor 50. The hydraulic oil stored in the auxiliary storage tank 53 is returned to the crankcase 62 through the hydraulic pressure return system 52 by operating the electric oil return pump 54.
Further, reference numeral 55 in the drawing is a pipe line connecting the hydraulic pressure introduction system 51 and the auxiliary storage tank 53, and reference numeral 56 is a check valve provided in the pipe line 55. By providing the pipe line 55 and the check valve 56, it is possible to avoid the oil pressure introduction system 51 from becoming negative pressure by sucking up oil from the auxiliary storage tank 53 for an emergency stop of the engine or the like.

  As described above, the gas fuel supply apparatus 10 of the present embodiment does not newly provide a hydraulic supply system (hydraulic pump or the like) for driving the hydraulic motor 50, but is electronically controlled by the gas-fired engine 1. By effectively using the high-pressure hydraulic oil of the unit 60 (hydraulic oil supplied from the hydraulic system 61), the LNG is boosted by the reciprocating pump 20 driven by the hydraulic motor 50. Therefore, the gas fuel supply apparatus 10 of the present embodiment minimizes new additional equipment by sharing the hydraulic equipment of the electronic control unit 60 in the hydraulic system necessary for supplying LNG as engine fuel. Can be suppressed.

  In such a gas-fired engine 1, the engine speed can be arbitrarily changed on the ship side according to the ship speed. For example, the engine speed increases as the engine load increases. The pump discharge amount and hydraulic pressure of the engine drive pump 66 to be supplied will increase. That is, for the reciprocating pump 20 for boosting liquefied gas, the required flow rate and pressure values increase as the amount of gas fuel consumed by vaporizing LNG increases. The high-pressure hydraulic fluid of the electronic control unit 60 is a suitable hydraulic source. Become.

In other words, the rotational speed of the hydraulic motor 50 that drives the reciprocating pump 20 is controlled by performing capacity control (oil amount control) of the engine drive pump 66 that supplies high-pressure hydraulic oil to the electronic control unit 60, that is, Since control is possible by adjusting the discharge amount of the engine drive pump 66, a mechanical speed reduction mechanism and motor speed control are not required. In this case, it is desirable to employ a variable displacement type such as a plunger pump for the engine drive pump 66 and control the discharge amount by adjusting the plunger inclination angle.
Accordingly, since the LNG discharge amount of the reciprocating pump 20 can be controlled by the rotation speed and hydraulic pressure of the hydraulic motor 50, the supply amount of LNG to the heating device 30 is the supply amount of high-pressure hydraulic oil as the engine load varies. In addition, control (increase / decrease) can be easily performed in conjunction with increase / decrease in hydraulic pressure.

In the reciprocating pump 20 driven by the hydraulic motor 50, the engine drive pump 66 serving as a hydraulic pump unit that supplies hydraulic pressure to the hydraulic motor 50 is connected to each other by the hydraulic piping of the hydraulic introduction system 51 and the hydraulic return system 52. It is connected. That is, the reciprocating pump 20 driven by the hydraulic motor 50 and the engine drive pump 66 serving as a hydraulic supply source can be separated by being connected by the hydraulic introduction system 51 and the hydraulic return system 52. The reciprocating pump 20 having no equipment or speed reduction mechanism can be easily installed in the gas danger zone.
Further, since the hydraulic pressure is supplied from the main engine of the ship, it is necessary to drive a power generation four-stroke engine that is inferior in thermal efficiency as compared to the two-stroke engine of the main engine in order to supply driving power to a separate hydraulic unit. The cost of operation can be reduced.

<Second Embodiment>
Next, a second embodiment of the gas-fired engine according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part similar to embodiment mentioned above, and the detailed description is abbreviate | omitted.
A gas-fired engine 1A according to the embodiment shown in FIG. 2 includes a gas fuel supply device 10A having a configuration different from that of the above-described embodiment. In this gas fuel supply apparatus 10A, the LNG fuel system has substantially the same configuration as that of the above-described embodiment, but the configuration of the hydraulic system that supplies hydraulic pressure to the hydraulic motor 50 is different.

The hydraulic system in this case drives the hydraulic pump 70 of a hydraulic pump unit that supplies hydraulic pressure for driving to the hydraulic motor 50 by effectively using the exhaust gas of the gas-fired engine 1A. The hydraulic pump 70 is a variable displacement pump that uses an exhaust turbine 81 that is operated by extracting a part of the exhaust gas from the engine exhaust static pressure pipe 80 as a drive source. For example, a plunger pump is used.
The exhaust turbine 81 includes an exhaust gas supply passage 82 for introducing a part of the exhaust gas from the engine exhaust static pressure pipe 80, and an exhaust gas discharge passage for guiding the exhaust gas that has worked in the exhaust turbine 81 to an air discharge chimney. 83 is connected.

An exhaust gas flow rate control valve 84 is provided in the exhaust gas supply channel 82 in order to adjust the flow rate of the exhaust gas supplied to the exhaust turbine 81 when necessary. Further, the exhaust gas supply passage 82 is provided with an exhaust gas bypass passage 85 that branches from the upstream side of the exhaust gas flow control valve 84. The exhaust gas bypass passage 85 is connected to an exhaust gas discharge passage 83, and a bypass flow rate adjusting valve 86 and an orifice 87 are provided in the middle of the passage.
The main flow of the exhaust gas discharged from the engine exhaust static pressure pipe 80 is supplied to the exhaust turbine 89 a of the supercharger 89 through the main exhaust gas supply passage 88. The exhaust gas main stream is led to the chimney through the main exhaust gas discharge passage 90 after driving the exhaust turbine 89a. The main exhaust gas discharge channel 90 is connected to the exhaust gas discharge channel 83 described above.

In the supercharger 89, a compressor 89b driven by the rotating shaft of the exhaust turbine 89a sucks and compresses air in the engine room. The compressed air for supply air (scavenging) compressed by the compressor 89b is cooled by the air cooler 91 and supplied to the supply air manifold 92 in a state where the air density is increased.
In addition, the code | symbol 93 in a figure is a cylinder of 1 A of gas-fired engines, and although it is 6 cylinders in the example of a structure shown in the figure, it is not limited to this.

According to such a gas-fired engine 1A, the hydraulic pump 70 is operated to supply hydraulic pressure to the hydraulic motor 50 by effectively using the exhaust gas released to the atmosphere as the hydraulic pressure supply source of the gas fuel supply apparatus 10A. It becomes possible.
The high-pressure hydraulic oil discharged from the hydraulic pump 70 is supplied to the hydraulic motor 50 through the hydraulic introduction system 51A. The hydraulic oil that has flowed into the auxiliary storage tank 53 by driving the hydraulic motor 50 is returned to the hydraulic oil storage tank 59 using the electric oil return pump 54.

  According to such a gas-fired engine 1A of the present embodiment, the hydraulic pump 70 driven by the exhaust turbine 81 in which the gas fuel supply apparatus 10A is operated by extracting a part of the exhaust gas from the engine exhaust static pressure pipe 80. Since the hydraulic pump 70 of the hydraulic pump unit that supplies the hydraulic pressure for driving to the hydraulic motor 50 is provided, the hydraulic pump 70 is driven by the effective use of the exhaust gas whose generation amount increases as the engine load increases, The LNG can be boosted by the reciprocating pump 20 driven by the hydraulic motor.

In this case, when the engine load increases, the amount of natural gas (engine fuel) that vaporizes LNG increases and the amount of exhaust gas also increases. Therefore, the flow rate and pressure of LNG required for the reciprocating pump 20 also increase. . Therefore, for such a reciprocating pump 20 for boosting LNG, the hydraulic pump 70 driven by the exhaust turbine 81 is supplied to the demand fluctuation on the fuel side and the hydraulic motor 50 driving the reciprocating pump 20 on the fuel supply side. Therefore, the oil pressure fluctuation becomes a suitable oil pressure supply source.
Further, the hydraulic system of the above-described embodiment can minimize the number of new additional devices, and can increase the pressure of the liquefied gas by the reciprocating pump 20 driven by the hydraulic motor 50.

By the way, in the gas fuel supply apparatus 10A of the above-described embodiment, the hydraulic pump 70 is of a variable displacement type, and a control unit (not shown) performs variable displacement control of the hydraulic pump 70 to adjust the rotation speed of the hydraulic motor 50, It is preferable to keep the gas fuel outlet pressure of the natural gas (gas fuel) supplied from the gas pressure reducing valve 40 to the gas-fired engine 1A constant.
By such variable displacement control, the rotation speed of the hydraulic motor 50 that drives the reciprocating pump 20 is controlled by displacement control (oil amount control) of the hydraulic pump 70, so that the mechanical speed reduction mechanism and the rotation speed of the motor Control is not required.

As a variable displacement control suitable in this case, for example, there is a system in which the hydraulic pump is a swash plate type, the opening degree of the exhaust gas flow control valve 84 is fixed and the swash plate angle is appropriately adjusted to control the pump discharge amount.
Further, in the gas fuel supply apparatus 10A of the above-described embodiment, the hydraulic pump 70 is of a constant capacity type, and a control unit (not shown) adjusts the rotational speed of the hydraulic motor 50 by controlling the rotational speed of the exhaust turbine 81, and the gas pressure reducing valve 40 A modification in which the gas fuel outlet pressure is kept constant is also possible. In this case, an exhaust gas flow rate control valve, that is, a flow rate control valve 84 whose opening degree can be adjusted is provided on the inlet side of the exhaust turbine 81, and the valve opening degree of the flow rate control valve 84 is appropriately adjusted so that the exhaust gas supply amount What is necessary is just to control the rotation speed of the exhaust turbine by.

Even in this case, since the rotational speed of the hydraulic motor 50 that drives the reciprocating pump 20 is adjusted by controlling the rotational speed of the exhaust turbine on the drive side, the mechanical speed reduction mechanism and the rotational speed control of the electric motor can be controlled. It becomes unnecessary.
Further, the reciprocating pump 20 driven by the hydraulic motor 50 and the hydraulic pump unit (hydraulic pump 70) for supplying hydraulic pressure to the hydraulic motor 50 can be connected separately by hydraulic piping. Therefore, the reciprocating pump 20 having no electrical equipment or speed reduction mechanism can be easily installed in the gas hazardous area.
Furthermore, since the exhaust gas energy discharged from the main engine of the ship is effectively utilized as hydraulic pressure, power generation is inferior in thermal efficiency compared to the main two-stroke engine to supply drive power to a separate hydraulic unit. This eliminates the need for driving a four-stroke engine and reduces operating costs.

<Third Embodiment>
Next, a third embodiment of the gas-fired engine according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part similar to embodiment mentioned above, and the detailed description is abbreviate | omitted.
The gas-fired engine 1B of the embodiment shown in FIG. 3 includes a gas fuel supply device 10B having a configuration different from that of the above-described embodiment. In this gas fuel supply device 10B, the LNG fuel system has substantially the same configuration as that of the above-described embodiment, but the configuration of the hydraulic system that supplies hydraulic pressure to the hydraulic motor 50 is different.

The hydraulic system in this case drives the hydraulic pump 70A of a hydraulic pump unit that supplies hydraulic pressure for driving to the hydraulic motor 50 by effectively using the exhaust gas of the gas-fired engine 1B. The hydraulic pump 70A is a variable displacement pump that is driven by the rotary shaft of the exhaust turbine 89a of the supercharger 89 that is operated by the exhaust gas discharged from the engine exhaust static pressure pipe 80. For example, a plunger pump is used. The
In the exhaust turbine 89a, a main exhaust gas supply flow path 88 for introducing exhaust gas from the engine exhaust static pressure pipe 80, and a main exhaust gas discharge flow path 90 for guiding the exhaust gas that has worked in the exhaust turbine 89a to the chimney for atmospheric discharge. And are connected.

Exhaust gas discharged from the engine exhaust static pressure pipe 80 is supplied to the exhaust turbine 89 a of the supercharger 89 through the main exhaust gas supply passage 88. The exhaust gas flow is guided to the chimney through the main exhaust gas discharge passage 90 after driving the exhaust turbine 89a.
In the supercharger 89, a compressor 89b driven by the rotating shaft of the exhaust turbine 89a sucks and compresses air in the engine room. The compressed air for supply air (scavenging) compressed by the compressor 89b is cooled by the air cooler 91 and supplied to the supply air manifold 92 in a state where the air density is increased.
In addition, the code | symbol 93 in a figure is a cylinder of the gas-fired engine 1B, and although it is 6 cylinders in the example of illustration shown in the figure, it is not limited to this.

According to such a gas-fired engine 1B, the hydraulic pump 70 is driven by the shaft of the exhaust turbine 89a of the supercharger 89 by effectively using the exhaust gas discharged to the atmosphere as the hydraulic supply source of the gas fuel supply device 10B. The hydraulic oil can be supplied to the hydraulic motor 50 by boosting the hydraulic oil introduced from the hydraulic oil storage tank 59.
The high-pressure hydraulic oil discharged from the hydraulic pump 70 is supplied to the hydraulic motor 50 through the hydraulic introduction system 51A. The hydraulic oil that has flowed into the auxiliary storage tank 53 by driving the hydraulic motor 50 is returned to the hydraulic oil storage tank 59 using the electric oil return pump 54.

  According to such a gas-fired engine 1B of the present embodiment, the gas fuel supply device 10B is driven by the hydraulic pump 70 driven by the exhaust turbine 89a that is operated by introducing the exhaust gas from the engine exhaust static pressure pipe 80. Since the hydraulic pump 70 of the hydraulic pump unit that supplies hydraulic pressure for driving to 50 is provided, the hydraulic pump 70 is driven by the effective use of exhaust gas whose generated amount increases as the engine load increases, and the hydraulic motor is driven. The LNG can be boosted by the reciprocating pump 20.

In this case, when the engine load increases, the amount of natural gas (engine fuel) that vaporizes LNG increases and the amount of exhaust gas also increases. Therefore, the flow rate and pressure of LNG required for the reciprocating pump 20 also increase. . Therefore, for such a reciprocating pump 20 for boosting the LNG, the hydraulic pump 70 driven by the exhaust turbine 89a is supplied to the demand fluctuation on the fuel side and the hydraulic motor 50 driving the reciprocating pump 20 on the fuel supply side. Therefore, the oil pressure fluctuation becomes a suitable oil pressure supply source.
Further, the hydraulic system of the above-described embodiment can minimize the number of new additional devices, and can increase the pressure of the liquefied gas by the reciprocating pump 20 driven by the hydraulic motor 50.

By the way, in the gas fuel supply apparatus 10B of the above-described embodiment, the hydraulic pump 70A is of a variable displacement type, and a control unit (not shown) performs variable displacement control of the hydraulic pump 70A to adjust the rotational speed of the hydraulic motor 50, It is preferable to keep the gas fuel outlet pressure of the natural gas (gas fuel) supplied from the gas pressure reducing valve 40 to the gas-fired engine 1B constant.
By such variable displacement control, the rotation speed of the hydraulic motor 50 that drives the reciprocating pump 20 is controlled by displacement control (oil amount control) of the hydraulic pump 70, so that the mechanical speed reduction mechanism and the rotation speed of the motor Control is not required.

As a variable displacement control suitable in this case, for example, a method is adopted in which a hydraulic pump is a swash plate type and a pump discharge amount is controlled by appropriately adjusting a swash plate angle.
Even in this case, since the rotational speed of the hydraulic motor 50 that drives the reciprocating pump 20 is adjusted by controlling the rotational speed of the exhaust turbine on the drive side, the mechanical speed reduction mechanism and the rotational speed control of the electric motor can be controlled. It becomes unnecessary.

Further, the reciprocating pump 20 driven by the hydraulic motor 50 and the hydraulic pump unit (hydraulic pump 70) for supplying hydraulic pressure to the hydraulic motor 50 can be connected separately by hydraulic piping. Therefore, the reciprocating pump 20 having no electrical equipment or speed reduction mechanism can be easily installed in the gas hazardous area.
Furthermore, since the exhaust gas energy discharged from the main engine of the ship is effectively utilized as hydraulic pressure, power generation is inferior in thermal efficiency compared to the main two-stroke engine to supply drive power to a separate hydraulic unit. This eliminates the need for driving a four-stroke engine and reduces operating costs.

As described above, according to the gas-fired engines 1, 1 </ b> A, 1 </ b> B of the present embodiment, the natural gas of the fuel is introduced into the combustion chamber at a high pressure as in, for example, an electronically controlled high pressure gas injection type low speed two-stroke diesel engine. In a high-pressure gas injection diesel engine to be supplied, a reciprocating pump 20 driven by a hydraulic pump that can be easily arranged in a gas danger zone is used to supply a fuel liquefied gas (for example, LNG) at a high pressure.
If the hydraulic pressure is supplied from the electronic control unit 60 on the engine side, it is not necessary to install a new hydraulic unit that supplies the hydraulic pressure to the hydraulic motor 50 for driving the reciprocating pump. In particular, in a limited ship, the ship space can be effectively used, such as increasing the load space.

In the method of driving the hydraulic pumps 70 and 70A using the shaft output of the exhaust turbine 81 and the supercharger 89 operated using exhaust gas, such as the gas-fired engines 1A and 1B, the reciprocating pump Since it is possible to minimize the components of the hydraulic unit that supplies hydraulic pressure to the drive hydraulic motor 50, it is possible to reduce the installation space and cost of the gas-fired engines 1A and 1B. Can effectively use the space in the ship, such as increasing the cargo space.
In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary, it can change suitably.

1, 1A, 1B Gas fired engine 10, 10A, 10B Gas fuel supply device 20 Reciprocating pump 21 LNG introduction piping 22 LNG supply piping 23 Recirculation line 24 Suction drum 25 Recirculation control valve 30 Heating device 40 Engine inlet gas pressure reducing valve (Gas pressure reducing valve)
DESCRIPTION OF SYMBOLS 50 Hydraulic motor 51,51A Hydraulic introduction system 52 Hydraulic return system 53 Secondary storage tank 54 Oil return pump 59 Hydraulic oil storage tank 60 Electronic control unit 61 Hydraulic system 62 Crankcase 63 Lubricating oil line 64 Lubricating oil pump 65 Filter unit 66 Engine drive Pump 67 Electric pump 70, 70A Hydraulic pump 80 Engine exhaust static pressure pipe 81 Exhaust turbine 82 Exhaust gas supply passage 83 Exhaust gas discharge passage 84 Exhaust gas flow control valve 88 Main exhaust gas supply passage 89 Supercharger 89a Exhaust turbine 89b Compressor 90 Main exhaust gas discharge passage 91 Air cooler 92 Air supply manifold

Claims (2)

A gas-fired engine of a gas injection diesel engine comprising an electronic control unit that drives an engine by controlling hydraulic oil with a controller and a solenoid valve, and a gas fuel supply device that boosts and supplies liquefied gas,
The gas fuel supply device comprises:
A reciprocating pump driven by a hydraulic motor to increase the pressure of the introduced liquefied gas to a desired pressure and discharge it;
A hydraulic introduction system that introduces a part of the hydraulic oil from a hydraulic system to which the hydraulic oil is supplied and supplies and drives the hydraulic motor;
A controller that adjusts the rotational speed of the hydraulic motor to keep the gas fuel outlet pressure constant;
With
The hydraulic motor and the reciprocating pump are installed in a gas hazardous area,
The gas-fired engine, wherein the controller controls the rotational speed of the hydraulic motor by adjusting a discharge amount of a hydraulic pump that supplies the hydraulic oil to the hydraulic system. A gas-fired engine of a gas injection diesel engine comprising an electronic control unit that drives an engine by controlling hydraulic oil with a controller and a solenoid valve, and a gas fuel supply device that boosts and supplies liquefied gas,
The gas fuel supply device comprises:
A reciprocating pump driven by a hydraulic motor to increase the pressure of the introduced liquefied gas to a desired pressure and discharge it;
A hydraulic introduction system that introduces a part of the hydraulic oil from a hydraulic system to which the hydraulic oil is supplied and supplies and drives the hydraulic motor;
A controller that adjusts the rotational speed of the hydraulic motor to keep the gas fuel outlet pressure constant;
With
Between the hydraulic motor and the reciprocating pump and the hydraulic pump that supplies the hydraulic oil to the hydraulic system, the hydraulic motor and the reciprocating pump are connected separately by hydraulic piping, A gas-fired engine that is installed in a gas hazardous area.

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