JP6391253B2 - Engine equipment - Google Patents

Description

  The present invention relates to an engine device serving as a drive source, and more particularly to an engine device that rotates an output shaft based on combustion by fuel gas.

  Conventionally, for example, in a ship such as a tanker or a transport ship or an onshore power generation facility, a diesel engine has been used as a drive source. However, exhaust gas from a diesel engine is rich in nitrogen oxides, sulfur oxides, particulate matter, and the like that are harmful substances that hinder environmental conservation. Therefore, in recent years, gas engine devices that can reduce the amount of harmful substances generated are becoming widespread as engines that can replace diesel engines.

  A so-called gas engine apparatus that generates power using fuel gas such as natural gas supplies a cylinder with a mixed gas obtained by mixing a fuel gas with air and burns it (see Patent Document 1). In the gas engine device of Patent Document 1, fuel gas is mixed with air compressed by a supercharger and supplied to a cylinder. In such a gas engine device, there is one that adjusts an air-fuel ratio by providing a throttle valve between an intake manifold that sucks into a cylinder and a supercharger and controlling the opening of the throttle valve.

JP 2003-262139 A

  By the way, in this type of gas engine device, for example, when the gas engine is in a no-load state due to some factor and the output is suddenly reduced, the opening of the throttle valve is suddenly reduced (the throttle valve is suddenly closed and operated). . If it does so, the supercharging pressure of the compressor in a supercharger will raise abnormally, and surging (pulsation) will generate | occur | produce in a supercharger by a partial backflow. The occurrence of the surging destroys the pressure balance of the compressor, causes an abnormality (riching) in the air-fuel ratio that is the ratio of the intake mass to the fuel mass, and causes abnormal combustion of the gas engine.

  Further, when a load is applied from a low load to a high load, the increase timing of the intake air inflow amount based on the throttle valve opening control is delayed with respect to the increase timing of the fuel gas injection amount by the gas injector. For this reason, even when the load is applied to a high load, the air flow rate control based on the throttle valve opening control is poorly responsive, resulting in a shortage in the intake air flow rate. May cause combustion.

  Therefore, the present invention has a technical problem to provide an engine device that has been improved by examining the above-described present situation.

According to the first aspect of the present invention, an intake manifold that supplies air into the cylinder, an exhaust manifold that exhausts exhaust gas from the cylinder, and a fuel gas mixed with the air supplied from the intake manifold to intake air into the cylinder. An engine comprising: a gas injector that compresses air with exhaust gas from the exhaust manifold; and an intercooler that cools compressed air compressed by the supercharger and supplies the compressed air to the intake manifold In the apparatus, a main throttle valve is provided at a connection point between the air discharge port of the supercharger and the intercooler inlet, and an air supply bypass flow connecting the air inlet of the supercharger and the intercooler inlet A bypass valve is disposed in the supply air bypass flow path, and the opening degree of the bypass valve Your is whether being executed is confirmed, in the case where the opening degree control of the bypass valve is not running, if prior SL engine load is not higher than the first threshold, opening control execution of the main throttle valve When the engine load exceeds the first threshold value, the main throttle valve is fixed at a predetermined opening, and the opening control of the main throttle valve is switched to the opening control of the bypass valve. If the opening control is being performed, when the load of the engine is reduced, the case where the engine load is greater than or equal to lower than said first threshold second threshold, continues opening control of the bypass valve When the engine load falls below the second threshold value, the opening degree of the bypass valve is fixed at a predetermined opening degree, and the opening degree control of the main throttle valve is controlled from the opening degree control of the bypass valve. Is that is switched on.

  According to the present invention, an intake manifold that supplies air into the cylinder, an exhaust manifold that exhausts exhaust gas from the cylinder, and a gas that mixes fuel gas with the air supplied from the intake manifold and intakes the cylinder In an engine apparatus comprising: an injector; a supercharger that compresses air using exhaust gas from the exhaust manifold; and an intercooler that cools compressed air compressed by the supercharger and supplies the compressed air to the intake manifold. A main throttle valve is provided at a connection point between the air discharge port of the supercharger and the intercooler inlet, and a supply air bypass passage connecting the air inlet of the supercharger and the intercooler inlet is provided. In addition, when a bypass valve is arranged in the supply air bypass flow path and the engine load increases When the engine load is lower than the first threshold value, the opening control of the main throttle valve is executed. When the engine load exceeds the first threshold value, the opening control of the main throttle valve is used to control the bypass valve. While switching to opening control, when the engine load decreases, if the engine load is greater than or equal to a second threshold lower than the first threshold, the bypass valve opening control is executed, and the engine When the load falls below the second threshold value, the opening control of the bypass valve is switched to the opening control of the main throttle valve. Therefore, the intake air intake system has the structure including the main throttle valve and the bypass valve. Since the air flow rate of the manifold can be controlled with high accuracy, the air flow rate can be controlled with high responsiveness to load fluctuations.

  According to the present invention, since the air supply bypass flow path functions as a buffer flow path for the supercharger and the intake manifold, the opening of the bypass valve is controlled to optimally adjust the air in accordance with the increase or decrease of the load. The response speed for setting the flow rate can be increased. In particular, since the bypass valve control with good responsiveness is executed in a high load region where the influence of the load change is large, the air flow rate is less excessive and insufficient with respect to the load change, and the optimum air-fuel ratio can be set. Furthermore, by providing hysteresis for the threshold for control switching, control switching can be executed smoothly.

  And a pressure sensor that measures the air pressure in the intake manifold, a load detection sensor that detects a load of the engine, and an engine control unit that controls the opening degree of each of the main throttle valve and the bypass valve. The engine control unit may determine whether the main throttle valve or the bypass valve is open according to a difference between a target air pressure based on the engine load detected by the load detection sensor and a measured pressure detected by the pressure sensor. Since the target pressure is set according to the detected load and the valve opening degree is controlled by feedback control, an appropriate air flow rate can be provided for the actual load. Therefore, the optimum air-fuel ratio can be set with good responsiveness to load fluctuations.

  Further, according to the present invention, since the air flow rate that passes through the main throttle valve can be optimally controlled by setting the air flow rate that is supplied to the intake manifold, it is possible to prevent shortage of the air flow rate that is supplied to the intake manifold. . As a result, the air flow rate can be controlled with high responsiveness even when the load suddenly increases, so that an appropriate air-fuel ratio can be provided, and the operation of the engine device can be stabilized.

  According to the present invention, the engine control unit sets the air flow rate supplied from the intake manifold by controlling the opening degree of the bypass valve when the load of the engine decreases. Thus, when the load is decreased, the bypass valve is controlled simultaneously with the main throttle valve, so that the air pressure at the air inlet / outlet in the supercharger can be stabilized and the occurrence of surging can be prevented.

1 is an overall side view of a ship according to an embodiment of the present invention. It is plane explanatory drawing of an engine room. It is plane explanatory drawing of an engine room. It is the schematic which shows the structure of the intake / exhaust path of the engine apparatus in embodiment of this invention. FIG. 2 is a schematic view schematically showing the inside of a cylinder head in the engine device. It is a control block diagram of the engine device. It is a side view of the engine device. It is a top view of the engine apparatus. It is an expansion perspective view of the engine device. It is a flowchart which shows the operation | movement of the air flow rate control in the engine apparatus. It is a time chart which shows the operation | movement of the air flow rate control in the engine apparatus. It is a schematic diagram which shows the operation | movement of fuel gas injection amount control. It is a flowchart which shows the operation | movement of target intake manifold pressure map correction control. It is a schematic diagram which shows operation | movement of target intake manifold pressure map correction | amendment control. It is a flowchart which shows the operation | movement of target sub fuel gas pressure map correction | amendment control. It is a control operation | movement flowchart at the time of load injection by an engine control apparatus. It is the same time chart. It is a flowchart which shows the opening degree control operation | movement with respect to the main throttle valve at the time of load reduction. It is the same time chart.

  Hereinafter, an embodiment in which the present invention is embodied will be described with reference to the drawings in the case where the invention is applied to a power generation mechanism mounted on an electric propulsion ship.

  First, the outline of the ship will be described. As shown in FIGS. 1 to 3, the ship 1 of the present embodiment includes a hull 2, a cabin 3 (bridge) provided on the stern side of the hull 2, and a funnel 4 (chimney behind the cabin 3). ) And a pair of propellers 5 and a rudder 6 provided at the lower rear part of the hull 2. In this case, a pair of skegs 8 are integrally formed on the stern side bottom 7. A propeller shaft 9 that rotates the propeller 5 is supported on each skeg 8. Each skeg 8 is formed symmetrically with respect to a hull center line CL (see FIG. 3) that divides the hull 2 in the left-right width direction. That is, in the first embodiment, twin skeg is adopted as the stern shape of the hull 2.

  A hold 10 is provided on the bow side and the center of the hull 2, and an engine room 11 is provided on the stern side of the hull 2. In the engine room 11, a pair of propulsion mechanisms 12 serving as a driving source for the propeller 5 are arranged on the left and right sides of the hull center line CL. Each propeller 5 is rotationally driven by the rotational power transmitted from each propulsion mechanism 12 to the propulsion shaft 9. The engine room 11 includes a power control panel 13 that controls power supply to each propulsion mechanism 12 and the like, and a plurality of (three in this embodiment) power generation mechanisms 14 that generate power to be supplied through the power control panel 13. Is provided. The interior of the engine room 11 is partitioned vertically by a deck and an inner bottom plate. The propulsion mechanism 12, the power control plate 13, the power generation mechanism 14, and the engine room 11 of the first embodiment are installed on the innermost bottom plate. Although not shown in detail, the hold 10 is divided into a plurality of sections.

  As shown in FIGS. 2 and 3, the propulsion mechanism 12 is a propulsion motor device 15 (dual fuel engine in the embodiment) that is a drive source of the propeller 5 and a deceleration that transmits the power of the propulsion motor device 15 to the propulsion shaft 9. The machine 22 is combined. The power generation mechanism 14 is a combination of a generator 23 that generates electric power to be supplied and a medium-speed engine device 21 that is a drive source of the generator 23. Here, the “medium speed” engine means one that is driven at a rotational speed of about 500 to 1000 revolutions per minute. Incidentally, a “low speed” engine is driven at a rotational speed of 500 revolutions per minute, and a “high speed” engine is driven at a rotational speed of 1000 revolutions per minute. The engine device 21 of the embodiment is configured to be driven at a constant speed within a medium speed range (about 700 to 750 revolutions per minute).

  The rear end side of the engine output shaft 24 protrudes from the rear surface side of the engine device 21. A generator 23 is connected to the rear end side of the engine output shaft 24 so that power can be transmitted. In the power generation mechanism 14, the generator 23 transmits the generated power to the power control panel 13 by rotating the generator 23 with the engine device 21. The power control panel 13 supplies a part of the electric power transmitted from each generator 23 to the propulsion motor device 15 to drive the propulsion motor device 15 to rotate. The power control panel 13 also supplies the power generated by each generator 23 to the electrical system in the hull 2 other than the propulsion motor device 15.

  In the propulsion motor device 15, the power of the propulsion motor device 15 that is rotationally driven based on the electric power from the power control panel 13 is transmitted from the rear end side of the motor output shaft 16 to the propulsion shaft 9 via the speed reducer 22. The Part of the power of the propulsion motor device 15 is decelerated by the reduction gear 22 and transmitted to the propulsion shaft 9. The propeller 5 is rotationally driven by the deceleration power from the speed reducer 22. The propeller 5 employs a variable pitch propeller capable of adjusting the ship speed by changing the blade angle of the propeller blades.

  Next, the structure of the gas engine apparatus which is an engine apparatus used as the electric power generation mechanism 14 in the said ship 1 is demonstrated with reference to FIGS. The gas engine device 21 (hereinafter simply referred to as “engine device 21”) is driven by a premixed combustion method in which a fuel gas such as natural gas is mixed with air and burned. 4 is a diagram showing an intake / exhaust system in the engine device 21, FIG. 5 is a schematic diagram schematically showing the inside of a cylinder head in the engine device 21, and FIG. 6 is a control block diagram in the engine device 21. It is.

  As shown in FIG. 3, the engine device 21 is connected to a gas fuel tank 32 provided in the ship 2 via a vaporizer 34 and a gas valve unit 35 to constitute a fuel gas supply path. The gas fuel tank 32 stores a liquefied fuel gas obtained by liquefying a gaseous fuel gas. The vaporizer 34 vaporizes the liquefied fuel (fuel gas) in the gas fuel tank 32 and sends it to the engine device 21 via the gas valve unit 35. In the gas valve unit 35, a part of the fuel gas returning from the engine device 21 is collected, and a gas leak or the like is confirmed by detecting the gas pressure in the unit.

  The engine device 21 is connected to the gas valve unit 35 through a main fuel gas passage 30 and a sub fuel gas passage 31. The main fuel gas flow path 30 includes a main fuel gas pressure regulator 110, and the main fuel gas pressure regulator 110 adjusts the gas pressure of the fuel gas supplied from the gas valve unit 35 to the engine device 21. . The main fuel gas flow path 30 includes a main fuel gas pressure regulator 110, and the main fuel gas pressure regulator 110 moves from a gas injector 98 (see FIG. 4) described later to the main chamber M (see FIG. 6). The gas pressure of the supplied fuel gas is adjusted. Further, the auxiliary fuel gas flow path 31 includes an auxiliary fuel gas pressure regulator 111, and the auxiliary fuel gas pressure regulator 110 is connected to the auxiliary chamber S (see FIG. 6) from a check valve 89 (see FIG. 6) described later. The gas pressure of the fuel gas supplied to) is adjusted.

  As shown in FIG. 4, the engine device 21 has a configuration in which a plurality of cylinders (cylinders) 36 (6 cylinders in this embodiment) are arranged in series on a cylinder block 25 described later. Each cylinder 36 communicates with an intake manifold (intake passage) 67 configured in the cylinder block 25 via an intake port 37. Each cylinder 36 communicates with an exhaust manifold (exhaust flow path) 44 disposed above a cylinder head 26 described later via an exhaust port 38. A gas injector 98 is disposed in the intake port 37 of each cylinder 36.

  Accordingly, air from the intake manifold 67 is supplied to each cylinder 36 via the intake port 37, while exhaust gas from each cylinder 36 is discharged to the exhaust manifold 44 via the exhaust port 38. The fuel gas is supplied from the gas injector 98 to the intake port 37, the fuel gas is mixed with the air from the intake manifold 67, and the premixed gas is supplied to each cylinder 36. The intake manifold 67 is provided with an intake manifold pressure sensor 39 that measures the air pressure in the intake manifold 67.

  In this embodiment, the amount of air in the intake manifold 67 is determined by the intake manifold pressure, but is not limited to this. For example, the flow rate of air supplied to the intake manifold 67 may be detected by a mass flow meter or an orifice flow meter, and the detected air flow rate may be used as the air amount of the intake manifold 67.

  The exhaust inlet of the turbine 49a of the supercharger 49 is connected to the exhaust outlet side of the exhaust manifold 44, and the air outlet (new air) of the intercooler 51 is connected to the air inlet side (new air inlet side) of the intake manifold 67. Outlet) is connected. The air discharge port (fresh air outlet) of the compressor 49 b of the supercharger 49 is connected to the air intake port (fresh air inlet) of the intercooler 51. A main throttle valve V1 is arranged between the compressor 49b and the intercooler 51, and the flow rate of air supplied to the intake manifold 67 is adjusted by adjusting the valve opening degree of the main throttle valve V1.

  An air supply bypass passage 17 for bypassing the compressor 49b connects the air inlet (fresh air inlet) side of the compressor 49b and the air inlet side of the intercooler 51. That is, the air supply bypass passage 17 is connected to the connection portion between the intercooler 51 and the main throttle valve V1 while being released to the outside air upstream of the air intake port of the compressor 49b. An air supply bypass valve V2 is disposed on the air supply bypass flow path 17, and the valve opening degree of the air supply bypass valve V2 is adjusted to pass through the air supply bypass flow path 17 from the downstream side of the main throttle valve V1. Adjust the flow rate of air flowing to the outside air.

  As described above, the intake system of the engine device 21 includes the intake manifold 67, the intercooler 51, the main throttle valve V1, the compressor 49b, and the air supply bypass valve V2. In the intake system of the engine device 21, an intercooler 51, a main throttle valve V1, and a compressor 49b are sequentially arranged from the intake manifold 67 toward the upstream side of the air flow. The air supply bypass valve V2 is provided on the air supply bypass passage 17 which is a bypass path that bypasses the compressor 49b. The exhaust system of the engine device 21 includes an exhaust manifold 44 and a turbine 49a. The turbine 49a is disposed from the exhaust manifold 44 toward the downstream side of the exhaust gas flow.

  As shown in FIG. 6, the engine device 21 has a cylinder 36 installed in the cylinder block 25, and a piston 78 is slidably accommodated in the cylinder 36. A cylinder head 26 is disposed above the cylinder block 25, and an ignition device 79 is inserted into the cylinder head 26. An intake valve 80 and an exhaust valve 81 are slidably installed on the outer peripheral side of the ignition device 79. . A sub chamber S is formed on the lower end side of the ignition device 79 in the ignition device 79. In addition, a spark plug 82 and a check valve 89 are inserted into the ignition device 79 so that each tip is positioned above the sub chamber S. In the cylinder 36, a main chamber M surrounded by the lower side of the cylinder block 25 and the top of the piston 78 is formed.

  That is, a cylindrical cylinder 36 is inserted into the cylinder block 25, and the engine output shaft 24 below the cylinder 36 is rotated by reciprocating the piston 78 in the vertical direction in the cylinder 36. In each cylinder head 26 on the cylinder block 25, an ignition device 79 loaded with a spark plug 82 and a check valve 89 is inserted into the cylinder 36 with its tip directed. The ignition device 79 has a tip disposed at the center position of the upper end surface of the cylinder 36, and a check valve 89 is connected to the auxiliary fuel gas passage 31. Therefore, when the engine device 21 is driven, the fuel gas injected from the check valve 89 in the sub chamber S of the ignition device 79 is ignited by the spark of the spark plug 82, and an ignition flame is formed at the center position of the main chamber M in the cylinder 36. (Combustion gas) is generated.

  A gas injector 89 is disposed in the intake port 37, and a gas injection nozzle of the gas injector 89 is inserted into an air flow path in the intake port 37. A gas injector 89 is connected to the main fuel gas flow path 30. In the air flow path in the intake port 37, the fuel gas injected from the gas injection nozzle 103 is mixed with the air flowing in from the intake manifold 67. Therefore, when the intake valve 80 is opened, the premixed gas in which the fuel gas from the gas injector 89 is mixed with the air from the intake manifold 67 flows into the main chamber M.

  In each cylinder head 26, the intake port 37 is opened and closed by moving the intake valve 80 up and down, and the exhaust port 38 is opened and closed by moving the intake valve 80 up and down. That is, when the intake valve 80 is opened, the air from the intake manifold 67 is sucked into the main combustion chamber in the cylinder 36 through the intake port 37, while the exhaust valve 81 is opened so that the air in the cylinder 36 is opened through the exhaust port 38. The combustion gas (exhaust gas) in the main combustion chamber is exhausted to the exhaust manifold 44. Therefore, when the engine device 21 is driven, an ignition flame (combustion gas) is generated by the ignition device 79, so that the premixed gas supplied to the main chamber M in the cylinder 36 via the intake valve 80 reacts. Generate premixed combustion.

  That is, when the engine device 21 is driven, the gas injector 98 injects fuel gas into the intake port 37. Therefore, in the intake port 37, the fuel gas injected from the gas injector 98 is mixed with the air flowing from the intake manifold 67. The mixed gas obtained by mixing the fuel gas with the air flows toward the intake valve 80 through the intake port 37. At this time, by opening the intake valve 80, the mixed gas is sucked into the main chamber M in the cylinder 36. Then, after closing the intake valve 80 and sliding the piston 78 to compress the mixed gas in the main chamber M, an ignition flame 79 is jetted into the main chamber M by the ignition device 79, and the mixed gas in the main chamber M is discharged. To burn. Thereafter, by opening the exhaust valve 81, the combustion gas (exhaust gas) in the main chamber M is exhausted to the exhaust manifold 44 through the exhaust port 38 in the cylinder head 26.

  The main fuel gas flow path 30 is provided with a main fuel gas pressure sensor 112 and a main fuel gas temperature sensor 113 for measuring the gas pressure and gas temperature of the fuel gas in the flow path. Based on the measurement result of the main fuel gas pressure sensor 112, the flow rate of the fuel gas supplied from the gas injector 98 to the intake port 37 is measured. Further, the temperature of the fuel gas supplied from the gas injector 89 is measured by the main fuel gas pressure sensor 113. An auxiliary fuel gas pressure sensor 114 that measures the gas pressure of the fuel gas in the passage is installed in the auxiliary fuel gas channel 31, and based on the measurement result of the auxiliary fuel gas pressure sensor 114, a check valve 89 is provided. The flow rate of the supplied fuel gas is measured.

  As shown in FIG. 6, the engine device 21 includes an engine control device 73 that controls each part of the engine device 21, and a spark plug 82 and a gas injector 98 are provided for each cylinder 36. The engine control device 73 gives control signals to the spark plug 82 and the gas injector 98 to control ignition by the spark plug 82 and gas fuel supply by the gas injector 98.

  The engine control device 73 controls the main fuel gas pressure regulator 110 and the sub fuel gas pressure regulator 111 to control the gas pressure (gas flow rate) of the fuel gas supplied from the main fuel gas passage 30 and the sub fuel gas passage 31. ). The engine control device 73 gives control signals to the main throttle valve V1 and the supply air bypass valve V2, respectively, and adjusts the valve opening degree to adjust the air pressure (intake manifold pressure) in the intake manifold 67.

  The engine control device 73 receives a measurement signal from a load measuring device (load detection sensor) 19 such as a watt transducer or a torque sensor, and calculates a load applied to the engine device 21. The engine control device 73 receives a measurement signal from the engine rotation sensor 20 such as a pulse sensor that measures the rotation speed of the crankshaft 24 and detects the engine rotation speed of the engine device 21. The engine control device 73 receives the measurement signal from the intake manifold pressure sensor (pressure sensor) 39 that measures the air pressure in the intake manifold 67 and detects the intake manifold pressure. The engine control device 73 receives the measurement signal from the lubricating oil temperature sensor 53 and detects the lubricating oil temperature Tj of the lubricating oil circulating in the engine device 21.

  The engine control device 73 includes a main fuel gas pressure sensor 112 that detects a main chamber fuel gas pressure Pm, a main fuel gas temperature sensor 113 that detects a main fuel gas temperature Tm, and a sub fuel gas pressure Ps as a sub chamber fuel flow rate. A measurement signal is received from the sub fuel gas pressure sensor 114 to be detected. The engine control device 73 drives and controls the main fuel gas pressure regulator 110 based on the measurement signals from the main fuel gas pressure sensor 112 and the main fuel gas temperature sensor 113, and supplies them to the gas injectors 98 of the intake ports 37. Adjust the main fuel gas flow rate. The engine control device 73 drives and controls the auxiliary fuel gas pressure regulator 111 based on the measurement signal from the auxiliary fuel gas pressure sensor 114 to adjust the flow rate of the auxiliary fuel gas supplied to the check valve 89 of each ignition device 79. .

  The engine control device 73 adjusts the valve opening degree in the gas injector 98 to set the flow rate of the fuel gas supplied into the main chamber M of each cylinder 36. Then, the engine control device 73 controls the ignition operation of the spark plug 82 to generate combustion in each cylinder 36 at a predetermined timing. That is, the gas injector 98 supplies fuel gas having a flow rate corresponding to the valve opening degree to the intake port 37, mixes it with air from the intake manifold 67, and supplies premixed fuel to the cylinder 36. Then, the sub fuel gas supplied from the check valve 89 is ignited in the sub chamber S of the ignition device 79 by the spark plug 82 in accordance with the injection timing of each cylinder 36. The combustion gas generated in the ignition device 79 is injected into the main chamber M and ignited in the cylinder 36 to which the premixed gas is supplied.

  Next, the external configuration of the gas engine device 21 (engine device 21) will be described with reference to FIGS. In the following description, the front / rear / left / right positional relationship in the configuration of the engine device 21 is designated with the connection side with the generator 23 as the rear side.

  As shown in FIGS. 7 and 8, the engine device 21 includes an engine output shaft 24 in a cylinder block 25 placed on a base table 27, and a cylinder head 26 in which a plurality of head covers 40 are arranged in a line in the front-rear direction. It is mounted on the block 25. The engine device 21 has a main fuel gas pipe 41, which is a part of the main fuel gas passage 30, extended in parallel to the head cover 40 row on the right side surface of the cylinder head 26, while A sub fuel gas pipe 42, which is a part of the fuel gas flow path 31, extends in parallel with the head cover 40 row.

  On the upper side of the main fuel gas pipe 41, an exhaust manifold (exhaust flow path) 44 extends in parallel with the head cover 40 row, and the outer periphery of the exhaust manifold 44 is covered with a heat shield cover 45. The heat shield cover 45 is configured to cover the outer peripheral surface and the rear end of the exhaust manifold 44. Since the air layer formed between the heat insulating cover 45 and the exhaust manifold 44 functions as a heat insulating layer, the influence of the surroundings due to exhaust heat from the exhaust manifold 44 is reduced. A side cover 43 that covers the auxiliary fuel gas pipe 42 is disposed on the left side surface of the cylinder block 25.

  As shown in FIGS. 7 to 9, the front end (exhaust outlet side) of the exhaust manifold 44 is connected to the supercharger 49 via the exhaust relay pipe 48. Therefore, the exhaust gas exhausted through the exhaust manifold 44 flows into the turbine 49a of the supercharger 49 through the exhaust relay pipe 48, whereby the turbine 49a rotates and the compressor 49b that is coaxial with the turbine 49a is rotated. Rotate. The supercharger 49 is disposed on the upper side of the front end of the engine device 21, and includes a turbine 49a on the right side and a compressor 49b on the left side. The exhaust outlet pipe 50 is arranged on the right side of the supercharger 49 and is connected to the exhaust outlet of the turbine 49a to exhaust the exhaust gas from the turbine 49a.

  An intercooler 51 that cools compressed air by a compressor 49b of the supercharger 49 is disposed below the supercharger 49. That is, the intercooler 51 is installed on the front end side of the cylinder block 25, and the supercharger 49 is placed on the intercooler 51. An air discharge port of the compressor 49b is provided in the left and right middle layer position of the supercharger 49 so as to open toward the rear (cylinder block 25 side). On the other hand, the upper surface of the intercooler 51 is provided with an air suction port that opens upward, and the compressed air discharged from the compressor 49b flows into the intercooler 51 through the air suction port. The air discharge port of the compressor 49b and the air intake port of the intercooler 51 are communicated with each other by an air supply relay pipe 52 connected at one end. A main throttle valve V1 is pivotally supported in the air supply relay pipe 52.

  The turbocharger 49 coaxially supports a compressor 49b and a turbine 49a that are arranged separately on the left and right, and the compressor 49b rotates based on the rotation of the turbine 49a introduced from the exhaust manifold 44 through the exhaust relay pipe 49. . Further, the supercharger 49 includes an intake filter 63 that removes outside air to be introduced, and a fresh air passage pipe 64 that connects the intake filter 63 and the compressor 49b on the left side of the compressor 49b on the fresh air intake side. As a result, the compressor 49 b rotates in synchronization with the turbine 49 a, so that outside air (air) sucked by the intake filter 63 is introduced into the compressor 49 b through the supercharger 49. The compressor 49b compresses the air sucked from the left side and discharges the compressed air to the air supply relay pipe 52 installed on the rear side.

  The air supply relay pipe 52 is opened at the upper front and connected to the discharge port behind the compressor 49b, while the lower side is opened and connected to the intake port on the upper surface of the intercooler 51. The intercooler 51 is connected to one end of the air supply bypass pipe 66 (the air supply bypass passage 17) at a branch port provided in the front air passage, and a part of the compressed air cooled by the intercooler 51. Is discharged to the air supply bypass pipe 66. The other end of the supply air bypass pipe 66 is connected to a branch port provided in front of the new air passage pipe 64, and a part of the compressed air cooled by the intercooler 51 passes through the supply air bypass pipe 66. It circulates in the pipe 64 and merges with the outside air from the air supply filter 63. Further, the air supply bypass pipe 66 pivotally supports an air supply bypass valve V2 in the middle thereof.

  When the intercooler 51 allows the compressed air from the compressor 49 b to flow from the rear left side through the air supply relay pipe 52, the intercooler 51 cools the compressed air based on the heat exchange action with the cooling water supplied from the water supply pipe 62. Inside the intercooler 51, the compressed air cooled in the left chamber flows through the front ventilation path and is introduced into the right chamber, and then, through the discharge port provided in the rear of the right chamber, the intake manifold 67 (see FIG. 4). Discharged.

  Further, the turbine 49 a of the supercharger 49 has a rear suction port connected to the exhaust relay pipe 48, and a right discharge port connected to the exhaust outlet pipe 50. Thus, the supercharger 49 introduces exhaust gas from the exhaust manifold 44 into the turbine 49a via the exhaust relay pipe 48, rotates the turbine 49a and simultaneously rotates the compressor 49b, and sends the exhaust gas to the exhaust outlet pipe. Exhaust from 50. The exhaust relay pipe 48 is opened at the rear and connected to the discharge port of the exhaust manifold 44, while the front is opened and connected to the suction port at the rear of the turbine 49a.

  An engine control device 73 that controls the operation of each part of the engine device 21 is fixed to the rear end surface of the cylinder block 25 via a support stay (support member) 74. On the rear end side of the cylinder block 25, a flywheel 76 that is connected to the generator 23 and rotated is installed, and an engine control device 73 is disposed on the flywheel housing 76a that covers the flywheel 76. . The engine control device 73 is electrically connected to sensors (pressure sensors and temperature sensors) in each part of the engine device 21 to collect temperature data, pressure data, and the like of each part of the engine device 21, and electromagnetics in each part of the engine device 21. A signal is given to the valve or the like to control various operations of the engine device 21 (plug ignition, gas pressure adjustment, valve opening adjustment, gas injection, cooling water temperature adjustment, etc.).

  As described above, the engine device 21 of the present embodiment is provided with the main throttle valve V1 at the connection point between the air outlet of the supercharger 49 and the inlet of the intercooler 51. The engine device 21 includes an air supply bypass passage 66 that connects the air inlet of the supercharger 49 and the inlet of the intercooler 51, and an air supply bypass valve V <b> 2 is disposed in the air supply bypass passage 66. . By adopting a structure including the main throttle valve V1 and the air supply bypass valve V2, the air flow rate of the intake manifold 67 can be controlled with high accuracy, so that the air flow rate can be controlled with high responsiveness even to load fluctuations. Since the air supply bypass flow path 66 functions as a buffer flow path for the compressor 49b and the intake manifold 67 of the supercharger 49, by controlling the opening degree of the air supply bypass valve V2, the air is optimally adjusted in accordance with the increase or decrease of the load. The response speed for setting the flow rate can be increased.

  The engine control device 73 sets the air flow rate supplied to the intake manifold 67 by executing the opening degree control of the supply air bypass valve V2 when the engine load increases. By executing the bypass valve control when the load is high, the air flow rate that passes through the main throttle valve V1 can be optimally controlled, so that the shortage of the air flow rate supplied to the intake manifold 67 can be prevented. As a result, the air flow rate can be controlled with high responsiveness even in response to a sudden increase in load, so that an appropriate air-fuel ratio can be provided, and the operation of the engine device 21 can be stabilized.

  The engine control device 73 sets the air flow rate supplied to the intake manifold 67 by executing the opening degree control of the air supply bypass valve V2 when the engine load decreases. When only the main throttle valve V1 is controlled at low load, the air flow rate suddenly decreases on the outlet side of the compressor 49b of the supercharger 49, and surging occurs in which the air in the compressor 49b reverses. By simultaneously controlling the valve V2, the air pressure at the inlet / outlet of the compressor 49b can be stabilized, and the occurrence of surging can be prevented.

  Further, in the engine device 21 of the present embodiment, the engine control device 73 performs opening degree control on the main throttle valve V1 when the engine load is in a low load range. On the other hand, the engine control device 73 sets the main throttle valve V1 to a predetermined opening when the engine load is in the middle / high load region, and performs opening control on the supply air bypass valve V2. Since the bypass valve control with good responsiveness is executed in the middle and high load region where the influence of the load fluctuation is large, the engine device 21 can be operated smoothly by suppressing the excess or deficiency of the air flow rate against the load fluctuation.

  Details of the intake manifold pressure control by the engine control device 73 will be described below with reference to the flowchart of FIG.

  As shown in FIG. 10, when receiving a measurement signal from the load measuring device (load detection sensor) 19 (STEP 1), the engine control device 73 executes the opening degree control (bypass valve control) of the supply air bypass valve V2. (STEP 2). When the bypass valve control is not executed (No in STEP 2), the engine control device 73 compares the engine load Ac with a predetermined load (first threshold) Ac1 based on the measurement signal received in STEP 1 (STEP 3). On the other hand, when the bypass valve control is being executed (YES in STEP 2), the engine control device 73 sets the engine load Ac to a predetermined load (second threshold) Ac2 (0 <Ac2 <) based on the measurement signal received in STEP1. Compare with Ac1) (STEP 4).

  In STEP 3, when the engine load Ac is equal to or less than the predetermined load Ac1 (No), the engine control device 73 assumes that the engine load Ac is in a low load range, and performs feedback control (PID) on the valve opening of the main throttle valve V1. Control) (STEP 5). At this time, the engine control device 73 sets a target value (target pressure) of the intake manifold pressure corresponding to the engine load. The engine control device 73 receives the measurement signal from the pressure sensor 39, confirms the measured value (measured pressure) of the intake manifold pressure, and obtains the difference from the target pressure. Thus, the engine control device 73 performs PID control of the valve opening degree of the main throttle valve V1 based on the difference value between the target pressure and the measured pressure, and brings the air pressure of the intake manifold 67 closer to the target pressure. Hereinafter, the opening control of the main throttle valve V1 is referred to as “main valve control”.

  On the other hand, when the engine load Ac exceeds the predetermined load Ac1 in STEP 3 (Yes), the engine control device 73 assumes that the engine load Ac is in the middle / high load range, and sets the valve opening of the main throttle valve V1 to the predetermined opening. (STEP 6). And the engine control apparatus 73 performs feedback control (PID control) with respect to the valve opening degree of the air supply bypass valve V2 (STEP 7). At this time, as in the case of the main valve control, the engine control device 73 receives the measurement signal from the pressure sensor 39, and based on the difference value between the target pressure and the measured pressure, PID control of the valve opening degree of the air supply bypass valve V2 And the air pressure of the intake manifold 67 is brought close to the target pressure.

  That is, when the engine load Ac is increasing and the predetermined load Ac1 is exceeded, the engine control device 73 switches from main valve control to bypass valve control as pressure control of the intake manifold pressure. Further, in this embodiment, when the predetermined load Ac1 is exceeded when the load increases, in STEP 4, the engine control device 73 fully opens the main throttle valve V1 and controls the opening of the supply bypass valve V2, thereby controlling the supply air bypass flow. The air flow rate in the passage 17 is controlled to adjust the supply manifold pressure. Since the bypass valve control with good responsiveness is executed in the middle and high load region where the influence of the load fluctuation is large, it is possible to suppress the excess or deficiency of the air flow rate with respect to the load fluctuation and set the optimum air-fuel ratio.

  In STEP 4, when the engine load Ac is equal to or greater than the predetermined load Ac2 (No), the engine control device 73 assumes that the engine load Ac is in the middle and high load range, and performs feedback control (bypass valve) with respect to the valve opening degree of the supply air bypass valve V2. Control) is continued (STEP 8). On the other hand, when the engine load Ac falls below the predetermined load Ac2 in STEP 4 (Yes), the engine control device 73 assumes that the engine load Ac is in a low load region, and opens the valve opening of the air supply bypass valve V2 as predetermined. (STEP 9). Then, the engine control device 73 performs feedback control (main valve control) on the valve opening of the main throttle valve V1 (STEP 10).

That is, when the engine load Ac are lowered, when less than a predetermined load Ac2 lower than a predetermined load Ac1, the engine control device 73, the pressure control of the intake manifold pressure, switches to the bypass valve control from the main valve control. As described above, the switching operation of the intake manifold pressure can be smoothly performed by giving hysteresis to the respective threshold values when the load is increased and when the load is decreased.

  As shown in FIG. 11, in the engine device 21 of the present embodiment, the engine control device 73 determines that the opening degree of the main throttle valve V1 when the engine load Ac is lower than the first threshold value Ac1 when the engine load Ac increases. When the control is executed and the engine load Ac exceeds the first threshold value Ac1, the opening degree control of the main throttle valve is switched to the opening degree control of the supply air bypass valve V2. On the other hand, when the engine load Ac decreases, the engine control device 73 executes the opening degree control of the supply air bypass valve V2 when the engine load Ac is equal to or higher than the second threshold value Ac2 lower than the first threshold value Ac1. When the engine load Ac falls below the second threshold Ac2, the opening control of the supply air bypass valve V2 is switched to the opening control of the main throttle valve V1.

  By adopting a structure including the main throttle valve V1 and the air supply bypass valve V2, the air flow rate of the intake manifold 67 can be controlled with high accuracy, so that the air flow rate can be controlled with high responsiveness even to load fluctuations. In addition, since the bypass valve control with good responsiveness is executed in a high load region where the influence of the load change is large, the air flow is not excessive or insufficient with respect to the load change, and the operation can be stably performed. Furthermore, by providing hysteresis for the threshold for control switching, control switching can be executed smoothly.

  Next, fuel injection amount (main fuel gas injection amount) control by the engine control device 73 will be described below. As shown in FIG. 12, the engine control device 73 stores a fuel injection amount map M1, and determines the main fuel gas flow rate to be injected from the gas injector 42 based on the fuel injection amount map M1. Note that the fuel injection amount map M1 represents the correlation between the engine speed Ne, the engine load Ac, and the command fuel injection amount Q as the fuel flow rate, and the command fuel for the engine speed Ne and the engine load Ac. The injection amount Q is determined.

  Upon receiving the engine load Ac measured by the load measuring device (load detection sensor) 19 and the engine speed Ne measured by the engine rotation sensor 20, the engine control device 73 refers to the fuel injection amount map M1. The command fuel injection amount Q is determined. Then, the engine control device 73 uses the first correction amount ΔQp based on the main chamber fuel gas pressure Pm, the second correction amount ΔQt based on the main fuel gas temperature Pt, or the lubricating oil temperature Tj on the determined command fuel injection amount Q. A correction calculation using the third correction amount ΔQtj is executed to calculate a corrected injection amount Q1. Accordingly, the flow rate of the main fuel gas injected from the gas injector 42 is controlled so as to be the corrected injection amount Q1 determined by the engine control device 73.

  In the engine device 21, when the main fuel gas pressure Pm increases, the density of the main fuel gas increases, and the amount of fuel injection necessary to cope with the same engine load Ac at a predetermined engine speed Ne decreases. Therefore, when the engine control device 73 receives the main fuel gas pressure Pm measured by the main fuel gas pressure sensor 112, the engine control device 73 makes it proportional to the increase in the main fuel gas pressure Pm in the correction calculation for calculating the corrected injection amount Q1. The corrected fuel injection amount Q1 is calculated by reducing the command fuel injection amount Q by the first correction amount ΔQp. That is, the first correction amount ΔQp is a correction amount that decreases in proportion to the increase in the main fuel gas pressure Pm.

  When the main fuel gas temperature Tm rises, the engine device 21 decreases the density of the main fuel gas, and increases the fuel injection amount necessary to cope with the same engine load Ac at the predetermined engine speed Ne. Therefore, when the engine control device 73 receives the main fuel gas temperature Tm measured by the main fuel gas temperature sensor 113, the engine control device 73 makes it proportional to the increase in the main fuel gas temperature Pt in the correction calculation for calculating the corrected injection amount Q1. The command fuel injection amount Q is increased by the second correction amount ΔQt to calculate the correction injection amount Q1. That is, the second correction amount ΔQt is a correction amount that increases in proportion to the increase in the main chamber fuel gas temperature Pt.

  When the lubricating oil temperature Tj rises, the engine device 21 decreases the viscosity of the lubricating oil, and the amount of fuel injection required to cope with the same engine load Ac at the predetermined engine speed Ne decreases. Therefore, when the engine control device 73 receives the lubricating oil temperature Tj measured by the lubricating oil temperature sensor 115, the engine control device 73 makes a third proportional to the increase in the lubricating oil temperature Tj in the correction calculation for calculating the corrected injection amount Q1. The command fuel injection amount Q is decreased by the correction amount ΔQtj to calculate the correction injection amount Q1. That is, the third correction amount ΔQtj is a correction amount that decreases in proportion to an increase in the lubricating oil temperature Tj.

  The engine control device 73 sets a target value (target pressure) Pim of the intake manifold pressure corresponding to the engine load when the above-described main valve control or bypass valve control is executed. At this time, the engine control device 73 refers to the stored target intake manifold pressure map M2 to determine the target pressure Pim. The target intake manifold pressure map M2 represents the correlation between the engine speed Ne, the engine load Ac, and the target pressure Pim, and determines the target pressure Pim with respect to the engine speed Ne and the engine load Ac. .

  Further, as shown in FIG. 13, the engine control device 73 rewrites the stored content of the target intake manifold pressure map M2 when a fuel injection amount that is equal to or greater than the determined fuel injection amount is required. That is, the engine control device 73 determines whether or not the fuel injection amount from the gas injector 98 is insufficient based on the engine load Ac measured by the load measuring device 19 and the engine speed Ne measured by the engine rotation sensor 20. (STEP 101). If it is determined that the fuel injection amount from the gas injector 98 is insufficient (Yes in STEP 101), the engine control device 73 corrects the target pressure Pim in the target intake manifold pressure map M2 to be small ( Rewrite and store (STEP 102).

  The case where the fuel injection amount from the gas injector 98 is required to be larger than the set fuel injection amount is, for example, that the target engine speed Nem is not reached with respect to the engine load Ac at the set fuel injection amount, or a predetermined amount This is a case where a larger fuel injection amount than the fuel injection amount Q calculated by the fuel injection amount map is required at the engine speed Ne and the predetermined engine load Ac.

  In such a case, the storage element in the target intake manifold pressure map M2 is rewritten so that the target pressure Pim in the target intake manifold pressure map M2 becomes small. Therefore, even when the fuel injection amount becomes insufficient, the air-fuel ratio can be obtained such that the required combustion effect can be obtained by reducing the intake manifold pressure at the predetermined engine speed Ne and the predetermined engine load Ac. That is, when fuel gas having a different composition is supplied to the engine device 21, the amount of heat generated by the fuel gas having a different composition is low, so that a larger fuel injection amount is required than usual. At this time, by correcting the target pressure Pim to be small, an appropriate excess air ratio can be realized, and deterioration of fuel consumption can be prevented.

  Further, as shown in FIG. 14, the engine control device 78 performs a correction operation on the target pressure Pim determined based on the target intake manifold pressure map M2 by using a correction amount ΔPtj based on the lubricating oil temperature Tj, thereby correcting the target pressure. Pim1 is calculated. Therefore, the engine control device 78 performs PID control on the valve opening degree of the main throttle valve V1 or the supply air bypass valve V2 based on the difference between the measured pressure from the pressure sensor 39 and the corrected target pressure Pim1.

  When the lubricating oil temperature Tj rises, the engine device 21 is in a cold state (a state where the lubricating oil temperature Tj is lowered), and the excess air ratio shifts to the rich side. There is a risk of engine stalling due to loss of control. Therefore, when the engine control device 73 receives the lubricating oil temperature Tj measured by the lubricating oil temperature sensor 115, the correction amount proportional to the decrease in the lubricating oil temperature Tj in the correction calculation for calculating the corrected target pressure Pim1. The corrected target pressure Pim1 is calculated by increasing the target pressure Pim by ΔPtj. By executing the pressure control of the intake manifold 67 based on the corrected target pressure Pim1, it is possible to maintain an appropriate excess air ratio even in the cold state.

  The engine control device 73 sets a target value (target pressure) Pim of the intake manifold pressure corresponding to the engine load when the above-described main valve control or bypass valve control is executed. At this time, the engine control device 73 refers to the stored target intake manifold pressure map M2 to determine the target pressure Pim. The target intake manifold pressure map M2 represents the correlation between the engine speed Ne, the engine load Ac, and the target pressure Pim, and determines the target pressure Pim with respect to the engine speed Ne and the engine load Ac. .

  As shown in FIG. 15, when receiving the engine load Ac measured by the load measuring device 19 and the engine speed Ne measured by the engine speed sensor 20, the engine control device 73 receives the target auxiliary fuel gas pressure map M3. The target auxiliary fuel gas pressure Psm is determined with reference to FIG. The target sub fuel gas pressure map M3 represents the correlation between the engine speed Ne, the engine load Ac, and the target sub fuel gas pressure Psm, and the target sub fuel gas pressure Psm with respect to the engine speed Ne and the engine load Ac. Is to determine.

  Further, as shown in FIG. 15, the engine control device 73 rewrites the stored contents of the target auxiliary fuel gas pressure map M3 when a fuel injection amount equal to or greater than the determined fuel injection amount is required. That is, the engine control device 73 performs fuel injection from the gas injector 98 based on the engine load Ac measured by the load measuring device 19 and the engine rotational speed Ne measured by the engine rotation sensor 20 as in STEP 101 of FIG. It is determined whether or not the amount is insufficient (STEP 201). When it is determined that the fuel injection amount from the gas injector 98 is insufficient (YES in STEP 201), the engine control device 73 increases the target sub fuel gas pressure Psm in the target sub fuel gas pressure map M3. It is corrected (rewritten) and stored (STEP 202).

  When the engine control device 73 determines that the fuel injection amount from the gas injector 98 is insufficient, the engine control device 73 corrects the target auxiliary fuel gas pressure Psm to increase. That is, when fuel gas having a different composition is supplied to the engine device 21, the amount of heat generated by the fuel gas having a different composition is low, so that a larger fuel injection amount is required than usual. At this time, by correcting the target auxiliary fuel gas pressure Psm so as to increase, an appropriate air-fuel ratio can be realized, and deterioration of fuel consumption can be prevented.

  The engine control device 73 increases the fuel injection amount from the gas injector 98 after the intake manifold pressure of the intake manifold 67 reaches the target pressure Pim when transitioning from the low load operation state to the high load operation state. Hereinafter, the control operation will be described by taking as an example a case where the engine control device 73 performs opening degree control (main valve control) on the main throttle valve V1 when a load is applied. FIG. 16 is a flowchart showing the control operation when the engine control device 73 applies a load. FIG. 17 is a time chart showing the control operation when the engine control device 73 applies a load.

  As shown in FIG. 16, the engine control device 73 is operated with the engine load Ac measured by the load measuring device 19 being equal to or less than a predetermined load Ac10, receives a load input command from the outside, and is commanded. It is confirmed whether the applied load is equal to or higher than a predetermined load application rate rAc1 (STEP 301). The load input rate rAc is the ratio of the input load to the engine rated load. The load application command is input to the engine control device 73 by, for example, an accelerator lever.

  When the engine control device 73 confirms that the condition in STEP 301 is satisfied (Yes), the engine control device 73 increases the opening D of the main throttle valve V1 by a predetermined opening ΔD (STEP 302). The engine control device 73 determines the predetermined opening degree ΔD based on the engine speed Ne measured by the engine speed sensor 20 and the load application rate rAc input from the outside. Then, the engine control device 73 checks whether or not the intake manifold pressure (measured pressure) Pi measured by the pressure sensor 39 is equal to or higher than the target intake manifold pressure (target pressure) Pim (STEP 303).

  In STEP 303, when the measured pressure Pi becomes equal to or higher than the target pressure Pim (Yes), the engine control device 73 increases the fuel injection amount from the gas injector 98 and injects it (STEP 304). Actually, when the load is applied and the engine speed Ne decreases, the injection amount of the main fuel gas from the gas injector 98 increases. Instead of the control operation of STEP 303 for confirming the state of the measured pressure Pi, it is possible to wait for a predetermined time after increasing the main throttle valve V1 by the predetermined opening ΔD in STEP 302.

  When the engine control device 73 controls each part according to the flowchart of FIG. 16 and a load input command is input from the outside by an accelerator lever or the like, as shown in the time chart of FIG. 17, first, the main throttle valve V1. Is increased by ΔD. When the engine control device 73 confirms that the intake manifold pressure Pi has reached the target intake manifold pressure Pim after executing the main valve control, the injection quantity Q of the main fuel gas from the gas injector 98 is increased.

  In order to simplify the description, the example in which the pressure of the intake manifold 67 is adjusted by the main valve control when the load is applied has been described. However, in order to adjust the pressure of the intake manifold 67, the main throttle valve V1 or the supply pressure is adjusted. Even when the air bypass valve V2 is controlled, the fuel injection amount from the gas injector 98 may be increased after the measured pressure becomes equal to or higher than the target pressure after receiving the load input command.

  When the opening of the main throttle valve V1 is closed when the load is reduced, the engine control device 73 performs the opening control on the main throttle valve V1 by gradually closing the opening of the main throttle valve V1. To do. FIG. 18 is a flowchart showing an opening control operation for the main throttle valve V1 by the engine control device 73, and FIG. 19 is a time chart showing a control operation when the load is reduced by the engine control device 73.

  As shown in FIG. 18, when the main control is performed, the engine control device 73 receives a load reduction command for reducing the opening D of the main throttle valve V1 to the target opening Dm (STEP 401). The opening degree D is decreased stepwise toward the target opening degree Dm (STEP 402). For example, reducing the opening degree D of the main throttle valve V1 stepwise means that the opening degree D is reduced at a speed of 10% / s. The speed of 10% / s in this example is a speed at which the opening degree D is decreased by an opening degree of 10% when the full opening is 100% in one second. Further, in STEP 401, the engine control device 73 receives the load reduction command after the load is reduced by, for example, an accelerator lever.

  When the opening degree D of the main throttle valve V1 is decreased stepwise, the engine control device 73 checks whether or not the intake manifold pressure (measured pressure) Pi measured by the pressure sensor 39 has become equal to or less than a predetermined pressure value Pi1. (STEP403). When it is confirmed that the measured pressure Pi in the intake manhold 67 has decreased to the predetermined pressure value Pi1 (YES in STEP 403), the engine control device 73 ends the opening degree control for the main throttle valve V1.

  When the engine control device 73 controls each part in accordance with the flowchart of FIG. 18, when a load reduction command is input from the outside by an accelerator lever or the like as shown in the time chart of FIG. 19, the main throttle valve V1 is opened. Close the degree step by step. When the engine control device 73 confirms that the intake manifold pressure Pi has gradually decreased to reach the predetermined pressure value Pi1, the opening of the main throttle valve V1 is fixed and the opening relative to the main throttle valve V1 is fixed. End control. As described above, by gradually closing the opening of the main throttle valve V1 when the load is reduced, the flow rate of air passing through the compressor 49b is reduced stepwise, so that surging in the supercharger 49 can be prevented.

  In addition, the structure of each part is not limited to embodiment of illustration, A various change is possible in the range which does not deviate from the meaning of this invention. The engine device of the present embodiment can also be applied to configurations other than the propulsion and power generation mechanism described above, such as a power generation device for supplying power to the electrical system in the hull and a drive source in a power generation facility on land. It is.

DESCRIPTION OF SYMBOLS 1 Ship 2 Hull 4 Funnel 5 Propeller 9 Propulsion shaft 11 Engine room 12 Propulsion and power generation mechanism 17 Supply bypass flow path 19 Load measuring device 20 Engine rotation sensor 21 Engine device (gas engine device)
22 Reducer 23 Generator 24 Output shaft (crankshaft)
25 Cylinder block 26 Cylinder head 30 Main fuel gas flow path 31 Sub fuel gas flow path 36 Cylinder 37 Intake port 38 Exhaust port 39 Pressure sensor 40 Head cover 41 Main fuel gas pipe 42 Sub fuel gas pipe 43 Side cover 44 Exhaust manifold 45 Heat shield Cover 48 Exhaust relay pipe 49 Supercharger 49a Turbine 49b Compressor 51 Intercooler 63 Intake filter 64 New air passage pipe 66 Air supply bypass pipe 67 Intake manifold 73 Engine control device 79 Ignition device 80 Intake valve 81 Exhaust valve 82 Spark plug 89 Check Valve 98 Gas injector 110 Main fuel gas pressure regulator 111 Sub fuel gas pressure regulator 112 Main fuel gas pressure sensor 113 Main fuel gas temperature sensor 114 Sub fuel gas pressure sensor 115 Lubricating oil temperature sensor V1 Intake throttle Valve V2 Air supply bypass valve V3 Exhaust bypass valve

Claims (1)

An intake manifold that supplies air into the cylinder, an exhaust manifold that exhausts exhaust gas from the cylinder, a gas injector that mixes fuel gas into the air supplied from the intake manifold and intakes the cylinder, and the exhaust In an engine apparatus comprising: a supercharger that compresses air using exhaust gas from a manifold; and an intercooler that cools compressed air compressed by the supercharger and supplies the compressed air to the intake manifold.
A main throttle valve is provided at a connection point between the air outlet of the supercharger and the intercooler inlet,
An air supply bypass passage connecting the air inlet of the supercharger and the intercooler inlet is provided, and a bypass valve is arranged in the air supply bypass passage,
It is confirmed whether or not opening control of the bypass valve is being executed,
If the opening control of the bypass valve is not running, if prior SL engine load is equal to or less than the first threshold value, the control of the opening degree of the main throttle valve is performed, the engine load exceeds the first threshold value And the main throttle valve is fixed at a predetermined opening, while the opening control of the main throttle valve is switched to the opening control of the bypass valve,
Wherein when the opening control of the bypass valve is running, before SL when the engine load is above said lower than the first threshold second threshold value, the opening degree control of the bypass valve is continuously performed, the When the engine load falls below a second threshold, the opening degree of the bypass valve is fixed to a predetermined opening degree, and the opening degree control of the bypass valve is switched to the opening degree control of the main throttle valve. .

Images