JP2016084794A - Load follow-up characteristic improving system for lean pre-mixture gas engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a substantial improvement of a load follow-up characteristic and make a positive prevention of accidental fire or knocking by always performing optimal, fast and positive controlling an air-fuel ratio of an engine.SOLUTION: This invention comprises: a first hydraulic pump (21) connected to a supercharger (10); a second hydraulic pump (22) connected to a rotational power generation member (1); oil passages (23, 24) connecting the two hydraulic pumps; and an air supply pressure sensor (5) for detecting an air supply pressure (P). The first hydraulic pump or the second hydraulic pump is a variable displacement hydraulic pump in which the operation is controlled by a controller having load information of a gas engine. The controller performs a relative assistance by a surplus power between the supercharger and the rotational power generation member in response to a load of the gas engine, controls the operation of the variable displacement hydraulic pump on the basis of the load of the gas engine and the air supply pressure, and further controls it in such a way that the air-fuel ratio of the gas engine may be kept within a predetermined range of the optimal air-fuel ratio by changing an engine speed of the supercharger through the first hydraulic pump.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a load followability improving system for a lean premixed gas engine.

  2. Description of the Related Art Conventionally, for example, a turbocharger equipped in a diesel engine or the like is configured such that a turbine is rotationally driven by exhaust energy of engine exhaust gas, and an air supply density of the engine is increased by a compressor that is rotated by the turbine. Used to improve efficiency.

  However, even if the turbocharger is installed in this way, there is a sufficient surplus in the exhaust energy depending on the engine load condition. Using this surplus exhaust energy without waste not only improves fuel efficiency but also protects the environment. It is strongly requested from the aspect.

  In order to effectively use the surplus exhaust energy of this engine, the applicant of the present application attaches a hydraulic pump to both the turbocharger and the engine, and uses this surplus exhaust energy via oil pressure to The engine-side hydraulic pump is driven to rotate by the pump to energize the engine, thereby improving fuel efficiency by waste heat recovery (see, for example, Patent Documents 1 and 2). The present applicant has already put this invention to practical use in a low-speed two-cycle diesel engine for ships.

  On the other hand, the surplus exhaust energy utilization device of the engine drives the hydraulic pump on the supercharger side to rotate by the hydraulic pump on the engine side via hydraulic pressure in the low load region of the engine where the supercharging of the turbocharger is insufficient. Thus, the rotation of the supercharger is urged, and thereby, the supercharging shortage of the supercharger in the low load region can be improved.

  In addition, when the hydraulic pump is attached to a separate generator instead of being attached to the engine, the heat efficiency is also improved by waste heat recovery at high load, and the supercharger is insufficient at low load. Can be eliminated.

  On the other hand, in recent years, a clean energy source has been demanded particularly from the viewpoint of environmental conservation, and a drastic reduction in the emission amount of CO2, SOX, NOX, etc. has become an urgent issue. In particular, from the viewpoint of reducing CO2 and SOX emissions, gas engines using gas fuels such as natural gas and LNG as the main fuel are rapidly spreading.

  Among these gas engines, medium-speed four-cycle lean (reburn) gas engines are mainly used in combination with generators in power generation facilities, and are operated using natural gas and LNG as the main fuel as described above. However, among them, LNG has a high self-ignition temperature and poor ignitability.

  For this reason, after injecting gas fuel into the air supply port and filling the air-fuel mixture into the cylinder, a pilot ignition method in which light oil or heavy oil is injected and ignited as pilot fuel, thereby burning the gas fuel air-fuel mixture, A so-called premixing system such as a spark ignition system that ignites the air-fuel mixture with a spark plug is employed. This lean premixed gas engine can greatly contribute to the reduction of NOx emissions.

JP 2006-242051 A JP 2011-214461 A

  However, the medium-speed 4-cycle lean premixed gas engine described above needs to be able to cope with rapid fluctuations in power demand when used as a power generation facility, and when used as an emergency power generation facility. It is necessary to be able to cope with a rapid load increase of the generator at the time of emergency start-up. For this reason, improvement of engine load followability has become a major issue.

  In particular, when a gas engine is used as a buffer power source for a renewable energy facility, it is necessary to frequently adjust the power generation amount on the gas engine side in accordance with fluctuations in the power generation amount of the renewable energy facility. Therefore, in order to popularize a medium-speed four-cycle lean premixed gas engine with a small amount of emission of CO2, SOX, NOX, etc. as a clean buffer power source, improvement of engine load followability is an important issue.

  Further, the medium-speed four-cycle lean premixed gas engine burns on the lean side of the stoichiometric air-fuel ratio to increase the output and reduce the above-mentioned NOx emission amount. Due to its characteristics, this lean combustion may cause misfire or knocking if the air-fuel ratio deviates from a certain range. Therefore, in order to achieve stable combustion, it is necessary to control so that the air-fuel ratio is always within a certain range. Here, the air-fuel ratio depends on the supply air pressure, but this supply air pressure is greatly influenced by the supercharger power, that is, the exhaust gas energy recovered by the turbocharger turbine.

  Therefore, when the engine load is increased, the supercharger has a sufficient surplus with respect to the air amount required on the engine side so that the air-fuel ratio of the engine falls within a certain range. Things must be used. By selecting a turbocharger with a large capacity, it is possible to perform an operation that avoids knocking in a stable combustion range by increasing the amount of air supply.

  On the other hand, in order to prevent misfire due to an excessive supply amount, a supply air bypass valve or an exhaust bypass valve is provided, and a part of the supply air supplied from the supercharger to the engine is discharged to the outside, or A part of the exhaust gas before being supplied to the turbocharger turbine is discharged to the outside so that the air-fuel ratio can be controlled to operate on a normal operating line.

  However, when this supply air bypass control or exhaust gas bypass control is performed, the increase in the number of revolutions of the turbocharger depends on the increase in the exhaust gas energy accompanying the increase in the engine load. There is a problem that control with responsiveness is difficult.

  The present invention has been made to solve such a problem, and in a lean premixed gas engine, the exhaust gas energy bypassed before or after the supercharger and discharged to the outside is recovered, and the engine is recovered. The lean air-fuel ratio can always be controlled optimally quickly and reliably, so that the load followability can be greatly improved and the occurrence of misfire and knocking can be reliably prevented. It is an object of the present invention to provide a load followability improvement system for a gas engine.

In order to solve the above-mentioned problem, the means employed by the present invention includes a first hydraulic pump connected to a supercharger of a lean premixed gas engine equipped with a supercharger, and a rotational power that generates rotational power. A second hydraulic pump connected to the generator, a first oil passage connecting the outlet of the first hydraulic pump and the inlet of the second hydraulic pump, the outlet of the second hydraulic pump, and the first A second oil passage that connects the inlet of the hydraulic pump, and a supply pressure sensor that is disposed in the supply passage of the gas engine and detects the supply pressure of the supply air after supercharging in the supercharger. The first hydraulic pump or the second hydraulic pump is a variable displacement hydraulic pump whose operation is controlled by the controller, and the controller having the load information of the gas engine is a variable displacement hydraulic pressure when the gas engine is under low load. A second hydraulic pump is generated by controlling the pump operation The first hydraulic pump is auxiliary driven by the generated hydraulic pressure and the rotational power generated by the rotational power generator is used to urge the turbocharger and control the operation of the variable displacement hydraulic pump when the gas engine is under heavy load. Then, a system for improving the load followability of a lean premixed gas engine in which the second hydraulic pump is auxiliary driven by the hydraulic pressure generated by the first hydraulic pump and the rotation power of the supercharger is energized by the rotation power of the supercharger. The controller controls the operation of the variable displacement hydraulic pump on the basis of the load of the gas engine and the supply air pressure detected by the supply air pressure sensor, and controls the rotation speed of the supercharger via the first hydraulic pump. By changing it, the air-fuel ratio of the gas engine is controlled so as to be within a predetermined range of the optimum air-fuel ratio.

  According to the load followability improving system of the lean premixed gas engine of the present invention, the controller has the load information of the gas engine, and controls the operation of the variable displacement hydraulic pump when the gas engine is under a low load. The first hydraulic pump is auxiliary driven by the hydraulic pressure generated by the hydraulic pump to urge the rotation of the supercharger by the rotational power generated by the rotational power generator, and the variable displacement hydraulic pump at a high load of the gas engine The second hydraulic pump is auxiliary driven by the hydraulic pressure generated by the first hydraulic pump by controlling the operation of the first hydraulic pump, and the rotation power of the supercharger is urged to rotate.

  In addition, the controller controls the operation of the variable displacement hydraulic pump based on the load of the gas engine and the supply air pressure detected by the supply air pressure sensor, and rotates the turbocharger via the first hydraulic pump. By changing the number, the air-fuel ratio of the gas engine is further controlled so as to be within a predetermined range of the optimum air-fuel ratio.

  That is, in the load following performance improvement system of the lean premixed gas engine according to the present invention, the control of the air-fuel ratio is performed to increase the exhaust gas energy that is not responsive as in the prior art, the operation of the supply bypass valve or the exhaust bypass valve, etc. Rather than entrusting, it can be done quickly and reliably by actively using hydraulic pressure.

  Therefore, the air fuel ratio of the gas engine is automatically and quickly controlled so as to always be within the predetermined range of the optimal air fuel ratio, and the load followability of the lean premixed gas engine can be greatly improved. Thereby, it is possible to reliably prevent the occurrence of misfire and knocking that are characteristic of a lean premixed gas engine.

  Further, in this lean premixed gas engine, urging to the supercharger by the rotational power of the rotational power generator at low load, and urging to the rotational power generator by the rotational power of the supercharger at high load Is performed integrally with the above-described air-fuel ratio control, and at the same time, the surplus exhaust gas energy can be effectively utilized.

  Note that either the first hydraulic pump or the second hydraulic pump may be a variable displacement hydraulic pump whose operation is controlled by a controller. Further, as the above-described rotational power generator, for example, a lean premixed gas engine in which the air-fuel ratio control is performed, a generator separately from the gas engine in which the air-fuel ratio control is performed, and the like are conceivable.

  In the load followability improving system of the lean premixed gas engine, the controller adjusts the supply pressure of the supply air supplied from the supercharger to the gas engine within a predetermined range of the optimal supply air pressure. It is desirable to control so that the air-fuel ratio of the engine is within a predetermined range of the optimal air-fuel ratio.

  The above-mentioned air-fuel ratio is a dimensionless number obtained by dividing the air mass of the fuel mixture by the fuel mass. The larger the numerical value, the leaner the air-fuel mixture, and the smaller the value, the richer the air-fuel mixture. As will be described later, the air mass of the fuel mixture can be derived from the supply air pressure. Therefore, by adjusting the supply pressure of the supply air supplied from the supercharger to the gas engine within the predetermined range of the optimal supply air pressure, the air-fuel ratio of the gas engine is kept within the predetermined range of the optimal air-fuel ratio. Can be controlled.

  In the load followability improvement system of the lean premixed gas engine, an air supply temperature sensor disposed in the air supply passage of the gas engine for detecting an air supply temperature after supercharging in the supercharger or outside the gas engine The controller further includes an outside air temperature sensor that detects an outside air temperature, the controller calculates a target air supply pressure based on a load of the gas engine, and a supply air temperature or an outside air temperature sensor detected by the air supply temperature sensor is detected. Based on the detected outside air temperature, the target supply pressure is corrected to calculate the optimal supply pressure, and the differential pressure between the supply pressure detected by the supply pressure sensor and the optimal supply pressure is calculated. When the air pressure exceeds a predetermined range, it is desirable to adjust the supply air pressure by controlling the operation of the variable displacement hydraulic pump and changing the rotational speed of the supercharger via the first hydraulic pump.

  In this way, the controller calculates the target supply pressure based on the load of the gas engine, and calculates the target supply pressure based on the supply temperature detected by the supply temperature sensor or the outside temperature detected by the outside temperature sensor. The optimum supply air pressure is calculated by correction, and the differential pressure between the supply air pressure detected by the supply air pressure sensor and the optimum supply air pressure is calculated. If this difference exceeds the specified range, the variable displacement hydraulic pump By controlling the operation of the engine and adjusting the supply air pressure by changing the rotation speed of the supercharger via the first hydraulic pump, the air-fuel ratio is brought into a region where misfire or knocking may occur, for example. In some cases, the air-fuel ratio can be quickly and reliably kept within a predetermined range where there is almost no possibility of misfire or knocking, and the lean premixed gas engine can be stably operated.

  In the load following performance improvement system of the lean premixed gas engine, the controller is variable when the differential pressure obtained by subtracting the optimum supply air pressure from the supply air pressure detected by the supply air pressure sensor is a negative number exceeding a predetermined range. It is desirable to adjust the air-fuel ratio of the gas engine to the lean side by controlling the operation of the displacement hydraulic pump and increasing the rotation speed of the supercharger via the first hydraulic pump to increase the supply air pressure. .

  As described above, when the differential pressure is a negative number exceeding a predetermined range, the operation of the variable displacement hydraulic pump is controlled to increase the rotation speed of the supercharger via the first hydraulic pump, thereby increasing the supply air pressure. By increasing the air-fuel ratio, the air-fuel ratio on the rich side can be reliably adjusted to the lean side and kept within the predetermined range of the optimal air-fuel ratio.

  In the load followability improving system of the lean premixed gas engine, the controller is configured such that when the differential pressure obtained by subtracting the optimum supply air pressure from the supply air pressure detected by the supply air pressure sensor is a positive number exceeding a predetermined range, The operation of the variable displacement hydraulic pump is controlled to reduce the rotational speed of the supercharger via the first hydraulic pump to lower the supply air pressure, thereby adjusting the air-fuel ratio of the gas engine to the rich side. desirable.

  In this way, when the differential pressure is a positive number exceeding a predetermined range, the operation of the variable displacement hydraulic pump is controlled to reduce the number of rotations of the supercharger via the first hydraulic pump, thereby increasing the supply air pressure. By lowering the air-fuel ratio, the air-fuel ratio on the lean side can be reliably adjusted to the rich side and kept within the predetermined range of the optimum air-fuel ratio.

In the load followability improvement system of the lean premixed gas engine, an oil passage interposed between the first oil passage and the second oil passage and between the first oil passage and the second oil passage. A hydraulic bypass valve that opens and closes the engine, and the controller switches the urging mode between urging the supercharger by the rotational power of the rotational power generator and urging the rotational power generator by the rotational power of the supercharger Sometimes it is desirable to open the hydraulic bypass valve.

  Thus, further comprising a hydraulic bypass valve that is interposed between the first oil passage and the second oil passage and opens and closes the oil passage between the first oil passage and the second oil passage, The controller opens the hydraulic bypass valve when the energization mode is switched between energization of the supercharger by the rotary power generator and energization of the rotary power generator by the supercharger. Each of the hydraulic pumps No. 2 only idles once when the energizing mode is switched.

  That is, the first oil passage and the first oil passage are opened by opening the hydraulic bypass valve at the time of switching the urging mode between the urging to the supercharger by the rotating power generator and the urging to the rotating power generator by the supercharger. In order not to cause a hydraulic pressure difference between the two oil passages, a sudden change in hydraulic pressure at the time of switching the urging mode is prevented, and the flow of hydraulic oil in the hydraulic circuit is made smooth.

  In the load followability improvement system of the lean premixed gas engine, the system further includes an air supply bypass valve for releasing the air supply from the supercharger to the outside from the air supply path, and the controller includes the rotational power of the rotational power generator. The charge bypass valve is opened when the boost mode is switched between the boost to the turbocharger and the boost to the rotating power generator by the rotational power of the turbocharger. It is desirable to release a part to the outside.

  Alternatively, in the load followability improvement system of the lean premixed gas engine, the system further includes an exhaust bypass valve for discharging the exhaust gas supplied from the gas engine to the supercharger to the outside from the exhaust path, and the controller generates rotational power. The exhaust bypass valve is opened to switch to the turbocharger when the mode is switched between the boost to the turbocharger by the rotational power of the body and the boost to the rotary power generator by the rotational power of the turbocharger. It is desirable to discharge a part of the supplied exhaust gas to the outside.

  In this way, in order to release the exhaust gas supplied from the gas engine to the supercharger from the exhaust passage to the outside from the supply passage, or the air supply bypass valve for releasing the intake air from the supercharger to the outside. An exhaust bypass valve is further provided, and the controller is configured to switch the air supply bypass valve or the exhaust bypass valve when the energization mode is switched between energizing the turbocharger by the rotary power generator and energizing the rotary power generator by the supercharger. To release the surplus air generated by the supercharger or the surplus exhaust gas supplied from the gas engine to the supercharger. Even if the air-fuel ratio control cannot be performed, the air-fuel ratio can be appropriately adjusted by the supply bypass valve or the exhaust bypass valve.

  In the load followability improving system of the lean premixed gas engine, the controller is configured to start rotating the turbocharger from the start of substantially reducing the addition to the turbocharger by the rotational power of the rotational power generator when the load of the gas engine is increased. It is desirable to open the air supply bypass valve only until substantially the end of the increase in the urging force applied to the rotational power generator by the power, and release a part of the air supply generated by the supercharger to the outside.

  Alternatively, in the load followability improving system of the lean premixed gas engine, the controller may be configured to start the supercharger from the start of substantially reducing the addition to the supercharger by the rotational power of the rotational power generator when the load of the gas engine increases. The exhaust bypass valve is opened only until almost the end of the increase in the force applied to the rotational power generator by the rotational power of the engine, and part of the exhaust gas supplied from the gas engine to the supercharger is released to the outside. Is desirable.

In this way, the controller may not perform sufficient adjustment of the surplus air supply by the air supply bypass valve or the surplus exhaust gas by the exhaust bypass valve so that the above-described air-fuel ratio control through the hydraulic pressure may not be sufficiently performed. By carrying out within the above-mentioned minimum required range including the range, the supply air supercharged by the supercharger or the unnecessary external release of the exhaust gas for operating this supercharger can be minimized. Further utilization of surplus exhaust gas energy can be achieved.

  In the load followability improving system of the lean premixed gas engine, it is desirable that the predetermined range of the air-fuel ratio is zero.

  Thus, by setting the predetermined range of the air-fuel ratio to zero, the air-fuel ratio of the gas engine can be adjusted to always be the optimum air-fuel ratio, thereby further improving the load followability. Further, it is possible to more reliably prevent the occurrence of misfire and knocking that are characteristic of a lean premixed gas engine. Further, since this air-fuel ratio control is performed via hydraulic pressure, fine and frequent control can be performed quickly and reliably.

  A system for improving load followability of a lean premixed gas engine according to the present invention includes a first hydraulic pump coupled to a supercharger of a lean premixed gas engine having a supercharger, and rotational power generation for generating rotational power. A second hydraulic pump connected to the body, a first oil passage connecting the outlet of the first hydraulic pump and the inlet of the second hydraulic pump, the outlet of the second hydraulic pump, and the first hydraulic pressure A second oil passage that connects the inlet of the pump, and a supply pressure sensor that is disposed in the supply passage of the gas engine and detects the supply pressure of the supply air after supercharging in the supercharger The first hydraulic pump or the second hydraulic pump is a variable displacement hydraulic pump whose operation is controlled by a controller having load information of the gas engine, and the controller is a variable displacement hydraulic pump at a low load of the gas engine. The second hydraulic pump by controlling the operation of The first hydraulic pump is auxiliary driven by the generated hydraulic pressure to boost the rotation of the supercharger by the rotational power generated by the rotational power generator, and the variable displacement hydraulic pump is operated at the time of high load of the gas engine. Improved load followability of a lean premixed gas engine in which the second hydraulic pump is auxiliary driven by the hydraulic pressure generated by the first hydraulic pump and the rotation power of the turbocharger is energized by the rotational power of the supercharger. In the system, the controller controls the operation of the variable displacement hydraulic pump based on the load of the gas engine and the supply air pressure detected by the supply air pressure sensor, and controls the supercharger via the first hydraulic pump. By changing the rotational speed, the supply air pressure is adjusted so as to be within a predetermined range of the optimal supply air pressure, and the air-fuel ratio of the gas engine is controlled to be within the predetermined range of the optimal air-fuel ratio. .

  Therefore, in a lean premixed gas engine, it is possible to always optimally quickly and reliably control the air-fuel ratio of the engine while recovering the exhaust gas energy bypassed and discharged to the outside before or after the supercharger. Therefore, the load followability can be greatly improved, and an excellent effect that the occurrence of misfire or knocking can be surely prevented can be achieved.

  Due to this significant improvement in load following capability, rapid fluctuations in power demand when using a lean premixed gas engine, for example, as a power generation facility, and rapid generators during emergency start-up when used as an emergency power generation facility It is possible to sufficiently cope with an increase in load and sudden fluctuations in the amount of power generated when used as a buffer power source for renewable energy facilities.

It is a trial figure which shows the load followability improvement system of the lean premixed gas engine of this invention. It is a block which shows the structure of control of the gas engine of FIG. FIG. 3 is a front part of a flowchart showing air-fuel ratio control of the gas engine of FIG. 1. FIG. It is a rear part of the flowchart of FIG. FIG. 4 is a rear part of the flowchart of FIG. 3, and is a flowchart showing a control different from FIG. 4. It is a graph which shows the relationship between the air fuel ratio and average effective pressure of the gas engine of FIG. It is a graph which shows the operating state of each component with respect to the load of the gas engine of FIG. It is a schematic diagram which shows the load followability improvement system of the premixed gas engine different from FIG. FIG. 3 is a schematic diagram showing a load followability improving system for a premixed gas engine different from FIG. 1. FIG. 9 is a schematic diagram showing a load followability improving system for a premixed gas engine different from FIG. 8.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the load followability improving system for a lean premixed gas engine according to the present invention will be described in detail with reference to FIGS.

  As shown in FIG. 1, a supercharger 10 is disposed in a gas engine (rotary power generator) 1. The compressor 11 and the turbine 12 of the supercharger 10 are connected by a rotating shaft 13. The compressor 11 of the supercharger 10 is connected to the supply pipe 2 of the gas engine 1, and the compressor 11 supplies pressurized supply air to the supply pipe (supply path) 2.

  The turbine 12 of the supercharger 10 is connected to the exhaust pipe 3 of the gas engine 1. The turbine 12 is rotationally driven by the exhaust gas of the gas engine 1, and the compressor 11 is rotated by the turbine 12 via the rotating shaft 13. Thereby, the air supply density of the engine is increased and the efficiency of the gas engine is improved.

  In the supply pipe 2 of the gas engine 1, a supply pressure sensor 5 that detects a supply pressure P after supercharging by the supercharger 10, and a supply air that detects a supply temperature T after supercharging by the supercharger 10. A temperature sensor 38 is provided. An air supply bypass valve 15 is provided in a form branched from an air supply path 14 connecting the supercharger 10 and the air supply pipe 2, and the air supply bypass valve 15 is pressurized by the turbocharger 10. A part of the supply air is discharged to the exhaust passage 16 of the turbine 12 of the turbocharger 10, that is, to the outside air (outside).

  A fixed displacement hydraulic pump (first hydraulic pump) 21 is connected to the rotary shaft 13 of the supercharger 10 via a transmission 17. A variable displacement hydraulic pump (second hydraulic pump) 22 is connected to the crankshaft 4 of the gas engine 1. The hydraulic pump 22 may be attached to the crankshaft 4 of the gas engine 1 via a transmission. The hydraulic pump 21 is not necessarily limited to a fixed capacity type.

  The hydraulic pump 22 is a variable displacement hydraulic pump having, for example, a swash plate type variable mechanism, and the discharge capacity can be changed by changing the position of the swash plate. The hydraulic pump 22 is not necessarily limited to the variable displacement hydraulic pump of the swash plate type variable mechanism, and may be another type of variable displacement hydraulic pump.

  As shown in FIG. 1, a main oil passage (first oil passage) 23 that connects an outlet 21 b of the hydraulic pump 21 and an inlet 22 a of a variable displacement hydraulic pump 22 is provided. A main oil passage 24 that connects the inlet 21 a of the hydraulic pump 21 and the outlet 22 b of the hydraulic pump 22 is provided. The hydraulic pump 21 and the hydraulic pump 22 are connected to each other by the two main oil passages 23 and 24. The two hydraulic pumps 21 and 22 and the two main oil passages 23 and 24 are incorporated in the hydraulic circuit 20.

When the gas engine 1 is under a high load, the hydraulic pump 21 is rotationally driven by the rotary shaft 13 of the supercharger 10 to generate a hydraulic pressure in the direction indicated by the solid line arrow in the drawing. At this time, the transmission 17 of the supercharger 10 functions as a speed reducer. The hydraulic oil discharged from the hydraulic pump 21 rotates the hydraulic pump 22 through the main oil passage 24 and returns to the hydraulic pump 21 through the main oil passage 23 again.

  The hydraulic pump 22 assists and urges the rotation of the crankshaft 4 of the gas engine 1. That is, at this time, the hydraulic pump 22 operates as a hydraulic motor. As described above, when the gas engine is under a high load, surplus exhaust energy of the gas engine 1 can be used for urging the crankshaft 4 of the gas engine 1 and waste heat can be effectively used.

  The electric motor 25 rotationally drives the hydraulic pump 27 of the tank 26 and supplies the hydraulic oil in the tank 26 to the main oil passages 23 and 24 via the check valves 28 and 29, respectively. When the hydraulic pressure generated by the hydraulic pump 21 is too high, the hydraulic pressure is released from the main oil passage 24 to the main oil passage 23 side via the relief valve 31 and the check valve 28.

  Due to the operation of the switching valve 33, part of the hydraulic oil in the main oil passage 23 is returned to the tank 26 through the switching valve 33. That is, the oil pressure in the main oil passage 24 is higher than the oil pressure in the main oil passage 23. The hydraulic oil that has passed through the switching valve 33 is returned to the tank 26 through the relief valve 34, the oil filter 35, and the oil cooler 36. By the operation of the switching valve 33, switching of the urging mode between the urging of the supercharger 10 by the gas engine 1 at the time of low load described later and the urging of the gas engine 1 by the supercharger 10 at the time of the high load described above. Is done.

  On the other hand, when the engine 1 is under a low load, the hydraulic pump 22 is rotationally driven by the crankshaft 4 of the gas engine 1 to generate a hydraulic pressure in the direction indicated by the dashed arrow in the figure. The hydraulic oil discharged from the hydraulic pump 22 rotates the hydraulic pump 21 through the main oil passage 23 and returns to the hydraulic pump 22 through the main oil passage 24 again. At this time, the transmission 17 of the supercharger 10 functions as a speed increaser. The hydraulic pump 21 assists and urges the rotation of the rotary shaft 13 of the supercharger 10 via the transmission 17 described above.

  At this time, the hydraulic pump 21 operates as a hydraulic motor. When the hydraulic pressure generated by the hydraulic pump 22 is too high, the hydraulic pressure is released from the main oil passage 23 to the main oil passage 24 side via the relief valve 30 and the check valve 29. By the operation of the switching valve 33, a part of the hydraulic oil in the main oil passage 24 is returned to the tank 26 through the switching valve 33 and the relief valve 34, the oil filter 35, and the oil cooler 36. That is, due to the operation of the switching valve 33, the hydraulic pressure of the main oil passage 23 becomes higher than the hydraulic pressure of the main oil passage 24.

  When the gas engine 1 is under a low load, the amount of exhaust gas from the gas engine 1 is not sufficient, and the exhaust energy necessary for supercharging the supercharger 10 cannot be obtained. However, in the load followability improving system of the lean premixed gas engine, the supercharger 10 can perform supercharging according to the load of the gas engine 1 and the acceleration of the gas engine 1 is promoted.

  Since the hydraulic pump 22 is a variable displacement type, the supercharger 10 is appropriately controlled according to the load of the gas engine 1 so as to have a predetermined rotational speed. The controller 50 shown in FIG. 2 operates the switching valve 33 so that the above-described control when the engine 1 is at a high load and control when the load is low are appropriately performed.

  A hydraulic bypass valve 37 is interposed between the two main oil passages 23 and 24. The hydraulic bypass valve 37 is closed when the gas engine 1 at the time of low load is energized to the supercharger 10 and when the gas engine 1 is energized by the supercharger 10 at the time of high load. There is a hydraulic pressure difference between the two main oil passages 23 and 24. However, when the hydraulic bypass valve 37 is opened, the hydraulic oil only circulates in the peripheral oil passages of the hydraulic pumps 21 and 22, and no hydraulic pressure difference is generated between the two main oil passages 23 and 24. 21 and 22 are idle.

  As shown in FIG. 2, the above-described supply air pressure sensor 5, the supply air temperature sensor 38 that detects the supply air temperature T, the above-described variable displacement hydraulic pump 22, the hydraulic bypass valve 37, the supply air bypass valve 15, switching Valves 33 are each electrically connected to the controller 50 and their operation is controlled by the controller 50. This controller 50 is supplied with load information of the gas engine 1 from an engine controller (not shown) and has load information of the gas engine 1.

  Next, the operation of the load followability improving system of the lean premixed gas engine will be described. As shown in FIG. 7, at the time t1 when the gas engine 1 is started, the hydraulic bypass valve 37 is opened. For this reason, the hydraulic pump 21 starts to rotate at the same time as the gas engine 1 is started. However, since the hydraulic bypass valve 37 is open, it is in an idling state where no hydraulic load is applied.

  The switching valve 33 is switched to a position where the hydraulic oil in the main oil passage 24 is returned to the tank 26. When the gas engine 1 is started, the rotational speed of the main generator 6 increases, and the rotational speed of the main generator 6 soon becomes a constant rotational speed by controlling the rotational speed on the main generator 6 side. Thereby, the power generation by the main generator 6 is started.

  At the same time, the supercharger 10 starts to rotate, but due to the shortage of the exhaust gas supplied from the gas engine 1, the supercharger efficiency is maintained at a constant low efficiency state. At the same time, the hydraulic pump 22 also starts to rotate, but since the hydraulic bypass valve 37 is open, it remains in the idling state where no hydraulic load is applied like the hydraulic pump 21.

  When the predetermined time t2 is reached, the hydraulic bypass valve 37 is closed and the swash plate position of the variable displacement hydraulic pump 22 moves to the maximum discharge side. Moreover, the load of the gas engine 1 begins to rise. As a result, energization of the supercharger 10 by the rotational power of the crankshaft 4 of the gas engine 1 via the hydraulic pumps 21 and 22 when the engine 1 is under low load is started. At the same time, the supercharger efficiency of the supercharger 10 starts to increase rapidly, and the shortage of air supply of the supercharger 10 when the gas engine 1 is under low load is resolved. In addition, air-fuel ratio control described later is also started.

  Further, at a predetermined time t3, the efficiency of the turbocharger 10 due to the exhaust gas of the gas engine 1 approaches the maximum efficiency, so that the swash plate position of the variable displacement hydraulic pump 22 starts to move to the neutral position, and the crankshaft of the gas engine 1 The urging force to the supercharger 10 by the rotational power of 4 gradually decreases.

  At the same time, it becomes impossible to temporarily perform air-fuel ratio control by a hydraulic system to be described later. For this reason, in order to release the surplus air supplied by the supercharger 10 to the outside air, the air supply by-pass valve 15 is opened to an angle corresponding to the required air supply bypass amount to adjust the air-fuel ratio, and the air-fuel ratio is lean. This prevents the misfire of the gas engine 1 from occurring.

  At this time, the controller 50 keeps the supply air pressure P within the predetermined range P0 of the optimal supply air pressure PSP2 and controls the air / fuel ratio of the gas engine to be within the predetermined range of the optimal air / fuel ratio, as in the air / fuel ratio control by the hydraulic system described later. The air supply bypass amount of the air supply bypass valve 15 is adjusted so that

  Therefore, when the urging mode is switched between urging the turbocharger 10 by the rotational power of the crankshaft 4 of the gas engine 1 and urging the crankshaft 4 of the gas engine 1 by the rotational power of the supercharger 10. However, the air-fuel ratio control by the air supply bypass valve 15 can control the air-fuel ratio of the gas engine to be surely within the predetermined range of the optimal air-fuel ratio.

When the predetermined time t4 is reached, the efficiency of the supercharger 10 becomes maximum, and the load of the gas engine 1 becomes the rated load. Accordingly, in order to switch the urging mode from low load to high load of the gas engine 1, the hydraulic bypass valve 37 is temporarily opened, the two hydraulic pumps 21 and 22 are idling, and the crank of the gas engine 1 is A state where the mutual energization between the shaft 4 and the supercharger 10 is not performed is established.

  At this time, the position of the switching valve 33 of the hydraulic circuit 20 is switched, and the gas engine 1 is driven by the rotational power of the supercharger 10 from the mode of urging the turbocharger 10 by the rotational power of the crankshaft 4 of the gas engine 1. The mode is switched to the bias mode for the crankshaft 4. In this way, the hydraulic bypass valve 37 is always opened when the position of the switching valve 33 is switched, preventing sudden fluctuations in the hydraulic pressure when the energizing mode is switched, and smoothing the flow of hydraulic oil in the hydraulic circuit 20. ing.

  Immediately thereafter, the hydraulic bypass valve 37 closes again, and the swash plate position of the variable displacement hydraulic pump 22 begins to move to the minimum discharge side. As a result, energization of the crankshaft 4 of the gas engine 1 by the rotational power of the supercharger 10 via the hydraulic pumps 21 and 22 when the engine 1 is under high load is started.

  At this time, the supercharger efficiency reaches the maximum efficiency. At the same time, air-fuel ratio control described later is started again. For this reason, the above-mentioned air supply bypass valve 15 starts to close. Further, at the predetermined time t5, the swash plate position of the variable displacement hydraulic pump 22 becomes the minimum discharge position, and the air supply bypass valve 15 is fully closed.

  Next, the air-fuel ratio control of the load followability improving system of the lean premixed gas engine will be described with reference to FIGS.

  As shown in FIG. 3, the controller 50 reads the engine load at that time from the engine controller or the like (step S2), and calculates the target supply air pressure PSP1 from the read engine load using a map (step S4).

  Then, the supply air temperature T detected by the supply air temperature sensor 38 is read (step S6), and the above-mentioned target supply air pressure PSP1 is corrected by the supply air temperature T to calculate the optimum supply air pressure PSP2 (step S8). . Next, the air supply pressure P detected by the air supply pressure sensor 5 is read (step S10), and a differential pressure ΔP obtained by subtracting the optimum air supply pressure PSP2 from the air supply pressure P is calculated (step S12).

  As shown in FIG. 4, it is determined whether or not the absolute value of the differential pressure ΔP is within a predetermined set value P0 (within a predetermined range) (step S16). If the determination result in step S16 is affirmative (Yes), that is, if the differential pressure ΔP between the supply air pressure P and the optimum supply air pressure PSP2 is within a predetermined range, the swash plate of the variable displacement hydraulic pump 22 The position is not adjusted, and the air-fuel ratio is not particularly adjusted.

  If the determination result in step S16 is negative (No), that is, if the differential pressure ΔP between the supply air pressure P and the optimal supply air pressure PSP2 exceeds a predetermined range, then whether or not this differential pressure ΔP is a negative number Is determined (step S18).

  If the determination result of step S18 is affirmative, that is, if the supply air pressure P is smaller than the predetermined range of the optimal supply air pressure PSP2, the air-fuel ratio is likely to be rich beyond the predetermined range, The amount of air supply is increased by increasing the number of revolutions of the supercharger 10, and control is performed so that the air supply pressure P falls within a predetermined range of the optimum air supply pressure PSP2, as shown in FIG.

Here, the air-fuel ratio is a dimensionless number obtained by dividing the air mass of the fuel mixture by the fuel mass. The larger the numerical value, the leaner the air-fuel mixture, and the smaller the value, the richer the air-fuel mixture. Also, since the gas equation of state is PV = RT, this can be rewritten as P = (RT / V). P represents the gas pressure, V represents the gas volume, and T represents the gas temperature.

  From this equation, it can be seen that the supply pressure P of the gas engine 1 indicates the supply density (1 / V), that is, is proportional to the air mass of the fuel mixture. Therefore, the air-fuel ratio of the gas engine 1 can be controlled to fall within the predetermined range of the optimum air-fuel ratio by adjusting the supply air pressure P within the predetermined range of the optimum air-supply pressure PSP2.

  If the determination result in step S18 is negative, that is, if the supply air pressure P is greater than the predetermined range of the optimum supply air pressure PSP2, the air-fuel ratio is likely to become leaner beyond the predetermined range. The rotational speed of the supercharger 10 is decreased to reduce the air supply amount, and the air-fuel ratio is adjusted to the rich side. As a result, as shown in FIG. 6, the air-fuel ratio is controlled so as to be within a predetermined range of the optimum air-fuel ratio.

  As a result, it is possible to reliably prevent the occurrence of knocking and misfire specific to the lean premixed gas engine. In particular, since the air-fuel ratio control is performed via hydraulic pressure, the air-fuel ratio control is performed quickly and reliably, and the load followability can be greatly improved. Then, the controller 50 repeats the above step S2 and subsequent steps again.

  As shown in FIG. 5, instead of the above-described step S16, it is determined whether or not the differential pressure ΔP obtained by subtracting the optimum supply air pressure PSP2 from the supply air pressure P is zero (step S26). The supply air pressure P may be controlled so as to always become the optimum supply air pressure PSP2.

  In this way, the predetermined range of the air-fuel ratio is also zero, the air-fuel ratio is always adjusted to the optimum air-fuel ratio, and the occurrence of knocking or misfire of the gas engine 1 can be further reliably prevented. In this lean premixed gas engine load followability improvement system, this air-fuel ratio control is performed via hydraulic pressure, so fine and frequent adjustments can be made quickly and reliably, and the supply pressure P is always optimal. It is easy to always control the air-fuel ratio to the optimum air-fuel ratio to the supply air pressure PSP2.

  According to the load followability improving system of the lean premixed gas engine, the controller 50 controls the variable displacement hydraulic pump 22 based on the load of the gas engine 1 and the supply pressure P detected by the supply pressure sensor 5. The operation is controlled to adjust the rotation speed of the supercharger 10 so that the air-fuel ratio of the gas engine 1 is controlled to be within a predetermined range of the optimal air-fuel ratio. It is automatically controlled so as to be within the predetermined range, and it is possible to reliably prevent the occurrence of misfire and knocking that are characteristic of the lean premixed gas engine 1.

  In addition, the air-fuel ratio control of the gas engine 1 is not performed by raising the exhaust gas energy or operating the air supply bypass valve or the exhaust bypass valve as in the conventional case. The fuel ratio control can be performed quickly and reliably.

  Due to this significant improvement in load followability, rapid fluctuations in power demand when the lean premixed gas engine 1 is used as a power generation facility, for example, and a rapid generator at the time of emergency start when used as an emergency power generation facility It is possible to sufficiently cope with a rise in the load of the power source and a sudden fluctuation in the amount of power generated when used as a buffer power source for renewable energy facilities.

  Further, in this gas engine 1, the crankshaft 4 of the gas engine 1 is energized to the supercharger 10 by the power of the crankshaft 4 of the gas engine 1 at the time of low load and the power of the supercharger 10 at the time of high load. Since the urging is performed integrally with the above-described air-fuel ratio control, the surplus exhaust gas energy can be used effectively at the same time.

  As described above, the hydraulic bypass valve 37 is provided between the oil passage 23 and the oil passage 24 to open and close the oil passage between the two oil passages 23, 24, and the controller 50 includes a gas engine. The hydraulic bypass valve 37 is opened when the urging mode is switched between urging the supercharger 10 by the power of one crankshaft 4 and urging the crankshaft 4 of the gas engine 1 by the supercharger 10.

  Therefore, at the time of switching the energization mode, the hydraulic pressure only idles for each of the two hydraulic pumps 23 and 24, and when the energization to the supercharger 10 is resumed by the power of the crankshaft 4 of the gas engine 1 after the energization mode is switched, or It is possible to prevent a sudden change in the hydraulic pressure when re-energizing the crankshaft 4 of the gas engine 1 due to the power of the supercharger 10 and to make the flow of hydraulic oil smooth.

  Further, as described above, when the load of the gas engine 1 is increased, the controller 50 starts from the time when the boosting to the supercharger 10 due to the rotational power of the crankshaft 4 of the gas engine 1 substantially starts to decrease. The supply air bypass valve 15 adjusts the supply air bypass amount only until the end of the substantial increase in the force applied to the crankshaft 4 of the gas engine 1 by the rotational power.

  As described above, the adjustment of the supply air bypass amount by the supply air bypass valve 15 is stopped by the supercharger 10 by stopping the adjustment within the necessary minimum range in which the above-described air-fuel ratio control may not be sufficiently performed. The unnecessary external discharge of the supplied air can be suppressed to the minimum, and the deterioration of fuel consumption can be prevented.

  The two-dot chain line in FIG. 7 shows the opening operation of the conventional air supply bypass valve 15 that is necessary to prevent misfire and knocking when the air-fuel ratio control through the oil pressure is not performed. In this case, even after the elapse of the predetermined time t5, the air supply by the supply air bypass valve 15 must be released to the outside, resulting in deterioration of fuel consumption.

  As shown in FIG. 8, a generator (rotary power generator) 7 is provided separately from the main generator 6 of the gas engine 1, and a variable displacement hydraulic pump (second hydraulic pump) 52 is provided. You may connect with this generator 7. In this case, when the gas engine 1 is under a high load, the hydraulic pump 21 is rotationally driven by the rotary shaft 13 of the supercharger 10 to rotationally drive the hydraulic pump 52 and rotate the generator 7 to generate power.

  As a result, the amount of power generated by the main generator 6 can be reduced, and the fuel consumption of the gas engine 1 can be reduced by that amount. Thereby, the effective utilization of the waste heat of the gas engine 1 can be aimed at.

  On the other hand, when the engine 1 is under a low load, the generator 7 operates as a motor to rotationally drive the hydraulic pump 52 and auxiliary drive the hydraulic pump 21 via hydraulic pressure. Thereby, the rotation of the supercharger 10 is energized, and the supercharger 10 can perform sufficient supercharging corresponding to the load of the gas engine 1, and acceleration of the gas engine 1 is promoted.

  The air-fuel ratio control of the gas engine 1 is performed by the controller 50 between the fixed displacement hydraulic pump 21 on the supercharger 10 side and the variable displacement hydraulic pump 52 on the generator 7 side. This is done by controlling the operation. The rest is the same as the case of the hydraulic pump 22 connected to the crankshaft 4 of the gas engine 1 shown in FIGS.

As shown in FIG. 9, a variable displacement hydraulic pump 61 is attached to the supercharger 10 side, and a fixed displacement hydraulic pump 62 is attached to the crankshaft 4 side of the engine 1.
By controlling the variable displacement hydraulic pump 61 on the supercharger 10 side to 0, the air-fuel ratio of the gas engine 1 and the rotation of the crankshaft 4 of the gas engine 1 at the time of low load of the gas engine 1 are controlled. It is also possible to energize the supercharger 10 with power and to energize the crankshaft 4 of the gas engine 1 with the rotational power of the supercharger 10 at high load.

  Others are the same as in the case of the load followability improving system of the lean premixed gas engine shown in FIG. 1 to FIG.

  As shown in FIG. 10, similarly to the load followability improving system of the lean premixed gas engine shown in FIG. 8, a generator (rotary power generator) 7 separate from the main generator 6 of the gas engine 1 is provided. A fixed displacement hydraulic pump (second hydraulic pump) 72 is connected to the generator 7 and a variable displacement hydraulic pump (first hydraulic pump) 71 is attached to the supercharger 10 side. The controller 50 controls the operation of the hydraulic pump 71 to the supercharger 10 by the air-fuel ratio of the gas engine 1 and the rotational power of the crankshaft 4 of the gas engine 1 when the gas engine 1 is under a low load. It is also possible to perform the urging of the gas engine 1 to the crankshaft 4 by the rotational power of the supercharger 10 at a high load.

  Others are the same as in the case of the load followability improving system of the lean premixed gas engine shown in FIG.

  Instead of the supply air temperature sensor 38 that detects the above-described supply air temperature T, an outside air temperature sensor 39 that is provided outside the gas engine 1 and detects the outside air temperature introduced into the gas engine 1 is provided. Based on the outside air temperature detected by the outside air temperature sensor 39, the target supply air pressure PSP1 may be temperature-corrected to calculate the optimum air supply pressure PSP2 (see steps S6 and S8 in FIG. 3).

  As indicated by a broken line in FIG. 2, the outside air temperature sensor 39 is also electrically connected to the controller 50, and its operation is controlled by the controller 50 in the same manner as the supply air temperature sensor 38. Therefore, the description regarding the operation is omitted.

  Further, instead of the air supply bypass valve 15 described above, an exhaust gas bypass valve 18 shown in FIG. 2 is provided in a form branched from an exhaust passage 19 connecting the supercharger 10 and the exhaust pipe 3. Accordingly, a part of the exhaust gas for rotationally driving the turbine 12 of the supercharger 10 may be bypassed to the exhaust passage 16 of the supercharger 10 and discharged to the outside air (outside).

  As indicated by a broken line in FIG. 2, the exhaust bypass valve 18 is also electrically connected to the controller 50, and its operation is controlled by the controller 50 in the same manner as the supply air bypass valve 15. Therefore, the description regarding the operation is omitted.

  The above-described system for improving the load followability of the lean premixed gas engine is merely an example, and various modifications can be made based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

1 Gas engine (rotary power generator)
2 Air supply pipe (air supply path)
3 Exhaust pipe 4 Crankshaft 5 Air supply pressure sensor 6 Main generator 7 Generator (rotary power generator)
DESCRIPTION OF SYMBOLS 10 Supercharger 11 Compressor 12 Turbine 13 Rotating shaft 14 Supply path 15 Supply bypass valve 16 Exhaust path 17 Transmission 18 Exhaust bypass valve 19 Exhaust path 20 Hydraulic circuit 21 Hydraulic pump (first hydraulic pump)
21a Inlet 21b Outlet 22 Hydraulic pump (second hydraulic pump)
22a Inlet 22b Outlet 23 Main oil passage (first oil passage)
24 Main oil passage (second oil passage)
25 Electric motor 26 Tank 27 Hydraulic pump 28, 29 Check valve 30, 31 Relief valve 33 Switching valve 34 Relief valve 35 Oil filter 36 Oil cooler 37 Hydraulic bypass valve 38 Supply air temperature sensor 39 Outside air temperature sensor 50 Controllers 52, 62, 72 Hydraulic pump (second hydraulic pump)
61, 71 Hydraulic pump (first hydraulic pump)
P Supply pressure P0 Predetermined set value PSP1 Target supply pressure PSP2 Optimal supply pressure ΔP Differential pressure T Supply air temperature t1 Start time t2, t3, t4, t5 Predetermined time

Claims (11)

A first hydraulic pump (21, 61, 71) connected to the supercharger of a lean premixed gas engine (1) equipped with a supercharger (10), and a rotational power generator ( 1, 7), the second hydraulic pump (22, 52, 62, 72), the outlet (21b) of the first hydraulic pump and the inlet (22a) of the second hydraulic pump are connected. The first oil passage (23), the second oil passage (24) connecting the outlet (22b) of the second hydraulic pump and the inlet (21a) of the first hydraulic pump, and the gas An air supply pressure sensor (5) disposed in an air supply path (2, 14) of the engine for detecting an air supply pressure (P) of the air supplied after supercharging in the supercharger; One hydraulic pump or the second hydraulic pump is connected to the controller (50) having load information of the gas engine. A variable displacement hydraulic pump whose operation is controlled, wherein the controller controls the operation of the variable displacement hydraulic pump when the gas engine is under a low load, and the hydraulic pressure generated by the second hydraulic pump The rotation of the supercharger is energized by the rotational power generated by the rotational power generator by assisting the first hydraulic pump, and the variable displacement hydraulic pump is operated at a high load of the gas engine. A lean premixed gas engine that controls the second hydraulic pump to be auxiliary driven by the hydraulic pressure generated by the first hydraulic pump and urges the rotation of the rotary power generator by the rotational power of the supercharger. In the load followability improvement system,
The controller controls the operation of the variable displacement hydraulic pump based on the load of the gas engine and the air supply pressure detected by the air supply pressure sensor, and performs the supercharging via the first hydraulic pump. A system for improving load followability of a lean premixed gas engine, wherein the air-fuel ratio of the gas engine is controlled to fall within a predetermined range of the optimal air-fuel ratio by changing the rotational speed of the machine.   The controller (50) sets the supply pressure (P) of the supply air supplied from the supercharger (10) to the gas engine (1) within a predetermined range (ΔP) of the optimum supply pressure (PSP2). 2. The load following capability of the lean premixed gas engine according to claim 1, wherein the air-fuel ratio of the gas engine is controlled to be within the predetermined range of the optimal air-fuel ratio by adjusting the air-fuel ratio to within the predetermined range. Improvement system.   An air supply temperature sensor (38) disposed in an air supply path (2, 14) of the gas engine (1) and detecting an air supply temperature (T) after supercharging in the supercharger or the gas engine And an outside air temperature sensor (39) for detecting an outside air temperature. The controller (50) calculates a target air supply pressure (PSP1) based on a load of the gas engine, and Based on the supply air temperature detected by the air temperature sensor or the outside air temperature detected by the outside air temperature sensor, the target supply air pressure is corrected to calculate the optimum supply air pressure (PSP2), and the supply air pressure A differential pressure (ΔP) between the supply air pressure (P) detected by the sensor (5) and the optimum supply air pressure is calculated, and when the differential pressure exceeds the predetermined range (P0), the variable capacity type Controls the operation of hydraulic pumps (22, 52, 61, 71) The lean premixed gas engine according to claim 2, wherein the supply pressure is adjusted by changing the rotational speed of the supercharger (10) via the first hydraulic pump. Load followability improvement system.   The controller (50) is a negative number in which a differential pressure (ΔP) obtained by subtracting the optimum supply pressure from the supply pressure (P) detected by the supply pressure sensor (5) exceeds the predetermined range (P0). In this case, the operation of the variable displacement hydraulic pump (22, 52, 61, 71) is controlled to increase the rotational speed of the supercharger (10) via the first hydraulic pump, thereby supplying the air. 4. The load followability improving system for a lean premixed gas engine according to claim 3, wherein the air fuel ratio of the gas engine is adjusted to a lean side by increasing a pressure. The controller (50) is configured to supply the supply air pressure (P) detected by the supply air pressure sensor (5).
If the differential pressure (ΔP) obtained by subtracting the optimum supply air pressure from the above is a positive number exceeding the predetermined range (P0), the operation of the variable displacement hydraulic pump (22, 52, 61, 71) is controlled. Then, the rotational speed of the supercharger (10) is decreased via the first hydraulic pump to lower the air supply pressure to adjust the air-fuel ratio of the gas engine to the rich side. 5. The load followability improving system for a lean premixed gas engine according to claim 3 or 4.   Hydraulic pressure interposed between the first oil passage (23) and the second oil passage (24) to open and close the oil passage between the first oil passage and the second oil passage. The controller (50) further includes a bypass valve (37), and the controller (50) urges the supercharger (10) by the rotational power of the rotational power generator (1, 7) and the rotational power of the supercharger. The load follow-up of the lean premixed gas engine according to any one of claims 1 to 5, wherein the hydraulic bypass valve is opened when an energization mode is switched between energization of the rotating power generator by the engine. Improvement system.   The controller (50) further includes an air supply bypass valve (15) for releasing the air supplied from the supercharger from the air supply path (14) to the outside, and the controller (50) includes the rotating power generator (1, 7). The air supply bypass valve is opened when the urging mode is switched between the urging of the supercharger (10) by the rotational power and the urging of the supercharger to the rotational power generator by the rotational power. 7. The system for improving the load followability of a lean premixed gas engine according to claim 1, wherein a part of the air supply generated by the supercharger is discharged to the outside.   The controller (50) is configured to start the reduction of the urging force applied to the supercharger (10) by the rotational power of the rotational power generator (1, 7) when the load of the gas engine (1) increases. The air supply bypass valve (15) is opened only until the end of substantially increasing the urging of the rotational power generator by the rotational power of the supercharger, and the supercharger generates the air supply. The system for improving load followability of a lean premixed gas engine according to claim 7, wherein a part of the engine is discharged to the outside.   The controller (50) further includes an exhaust bypass valve (18) for discharging exhaust gas supplied from the gas engine (1) to the supercharger (10) from an exhaust passage (19) to the outside. When the urging mode is switched between the urging of the rotating power generator (1, 7) to the supercharger (10) by the rotating power and the urging power of the supercharger to the rotating power generator by the rotating power. The lean according to any one of claims 1 to 6, wherein the exhaust bypass valve is opened to release a part of the exhaust gas supplied from the gas engine to the supercharger to the outside. A system for improving the load following capability of premixed gas engines.   The controller (50) is configured to start the reduction of the urging force applied to the supercharger (10) by the rotational power of the rotational power generator (1, 7) when the load of the gas engine (1) increases. The exhaust bypass valve (18) is opened and supplied from the gas engine to the supercharger only until the end of substantially increasing the urging of the rotational power generator by the rotational power of the supercharger. The system for improving load followability of a lean premixed gas engine according to claim 9, wherein a part of the exhaust gas is discharged to the outside.   The load followability improving system for a lean premixed gas engine according to any one of claims 1 to 10, wherein the predetermined range of the air-fuel ratio is zero.

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