JP2005069061A - Control method for dual fuel engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method for a dual fuel engine with improved startability of an engine. <P>SOLUTION: When the engine is started by mixed fuel of light oil and fuel gas with insufficient calorific value as a single fuel, and the calorific value itself fluctuating, the engine is started by light oil only. Then, after a drive load of the engine starts to rise, the engine is controlled to mix fuel gas to light oil. When supply of fuel gas to the engine is stopped upon stopping of the engine, the engine is controlled to drive by only light oil for a predetermined time and then to stop. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is a dual fuel in which an engine is driven by a mixed fuel obtained by mixing a low calorie gas generated by pyrolyzing waste with a high calorie fuel such as light oil or natural gas that generates a sufficient calorific value by itself. The present invention relates to an engine control method.

  Conventionally, a dual fuel engine engine is driven by a mixed fuel that is a mixture of biogas such as methane gas generated when anaerobic fermentation of organic waste such as garbage and livestock manure is mixed with light oil. A device that operates a machine is known (for example, see Patent Document 1).

  In addition, woody biomass such as thinned wood, pruned branches, construction waste, and cut grass is pyrolyzed in a pyrolysis furnace to produce combustible gas (pyrolytic gas), and this combustible gas and high-calorie fuel such as light oil and natural gas. In some cases, the generator is operated by driving the engine of the dual fuel engine with the mixed fuel.

However, as in the latter case, combustible gas obtained by pyrolyzing wood biomass does not have stable moisture content in the waste, and the raw material itself is not of constant quality. Even when it is produced by a cracking furnace, it cannot be treated as a fuel with a constant composition, and it cannot be treated as a low-calorie fuel, which alone has an insufficient calorific value and the calorific value itself fluctuates. is there. Therefore, a dual fuel engine uses a mixed fuel that is a mixture of low-calorie fuel (combustible gas) that has a calorific value that is not enough and fluctuates by itself, compared to a high calorie fuel that generates a sufficient calorific value. It has been done to drive the engine.
JP 2002-309997 A

  However, since the calorific value of the low calorie fuel mixed with the high calorie fuel in the dual fuel engine described above fluctuates, the total calorific value of the mixed fuel supplied to the engine of the dual fuel engine greatly fluctuates. It was. Therefore, if the mixed fuel remains in the engine at the time of starting the engine, or if the mixed fuel is newly supplied to the engine, an appropriate air-fuel ratio cannot be obtained, and the startability of the engine is significantly deteriorated. Yes.

  The present invention has been made in view of such points, and an object of the present invention is to provide a control method of a dual fuel engine that can improve the startability of the engine.

  In order to achieve the above object, the solution provided by the invention according to claim 1 is a high calorie fuel that generates a sufficient calorific value by itself, and the calorific value of this high calorie fuel alone is insufficient. It is premised on a dual fuel engine control method in which the engine is driven by a mixed fuel obtained by mixing a low calorie fuel whose calorific value itself varies. Then, when starting the engine, the engine is started only with the high calorie fuel, and then the low calorie fuel is mixed with the high calorie fuel after the driving load of the engine exceeds a certain level.

  Because of this specific matter, when starting the engine, the engine is started only with high-calorie fuel, so the total heat of the mixed fuel is the same as when the engine was started with a mixed fuel of high-calorie fuel and low-calorie fuel. The amount does not fluctuate greatly, and an appropriate air-fuel ratio is obtained only by the high-calorie fuel, and the engine startability can be improved. Moreover, since the low-calorie fuel is mixed with the high-calorie fuel after the engine driving load exceeds a certain level after the engine is started, it is possible to actively use the low-calorie fuel without causing misfire of the engine. Become.

  Further, in order to achieve the above object, the solution provided by the invention according to claim 2 is based on the dual fuel engine control method premised on the invention according to claim 1 and when the engine is stopped. , The supply of low-calorie fuel mixed with high-calorie fuel is stopped before the engine is stopped, and then the engine is controlled by driving the engine for a certain period of time only with the high-calorie fuel. .

  Because of this specific matter, after stopping the supply of low-calorie fuel to the engine when the engine is stopped, the engine is stopped only by driving the engine for a certain period of time with only high-calorie fuel. The engine does not stop with the mixed fuel remaining in the engine as if the engine had been stopped with the fuel mixture supplied with the fuel. The remaining of the mixed fuel (low-calorie fuel) is eliminated and the air-fuel ratio does not fluctuate at the time of start-up, and the engine startability can be improved with an appropriate air-fuel ratio. In addition, a large amount of water contained in the low calorie does not stay in the engine, and the engine can be reliably started.

  And in order to achieve the said objective, the solution which the invention concerning Claim 3 took is the high calorie fuel which generate | occur | produces sufficient calorific value independently, and calorific value is inadequate with respect to this high calorie fuel alone. It is premised on a control method for a dual fuel engine in which a plurality of engines are driven by a mixed fuel obtained by mixing a low calorie fuel that varies and the calorific value itself varies. When starting a plurality of engines, the first engine is started with only high-calorie fuel, and after the driving load of the first engine exceeds a certain level, the first engine is reduced with respect to high-calorie fuel. The first engine is continuously driven by the mixed fuel obtained by mixing the caloric fuel, and then the mixing ratio of the high calorie fuel in the mixed fuel driving the first engine is below a certain value. When it is reached, it is determined that the mixing ratio of the low calorie fuel in the mixed fuel is increasing, that is, there is a sufficient amount of low calorie fuel to supply to the second engine, and the second engine Is started with only high-calorie fuel, and after the driving load of this second engine becomes equal to or higher than that of the first engine, 2 is mixed with mixed fuel obtained by mixing high-calorie fuel with low-calorie fuel. Drive the second engine Continue to carried out. After that, when the mixing ratio of the high calorie fuel in the mixed fuel driving the second engine reaches a certain value or less, the subsequent engines are controlled to be sequentially started according to the above procedure. .

  Because of this specific matter, each engine is started only with high-calorie fuel when starting multiple engines, so that each engine is started with a mixed fuel of high-calorie fuel and low-calorie fuel. The total calorific value of the mixed fuel does not fluctuate greatly, and an appropriate air-fuel ratio is obtained only by the high-calorie fuel, and the startability of each engine can be improved. Moreover, after the first engine is started, the low calorie fuel is mixed with the high calorie fuel after the driving load of the engine exceeds a certain level, and the mixing ratio of the high calorie fuel in the mixed fuel reaches a certain value or less. Since the next engine is started at the time, a plurality of engines are started one by one according to the amount of low calorie fuel supplied from the low calorie fuel supply source. Each engine is misfired without inadvertently increasing the mixing ratio of high-calorie fuel in the mixed fuel when the amount of low-calorie fuel is low, such as when starting each engine at the same time The consumption of high-calorie fuel can be reduced without incurring low-calorie fuel, and low-calorie fuel can be used efficiently.

  In order to achieve the above object, the solution provided by the invention according to claim 4 is similarly premised on the control method of the dual fuel engine assumed in the invention according to claim 3. And when the supply amount of the low calorie fuel supplied from the low calorie fuel supply source to a plurality of engines has decreased, the supply of the low calorie fuel to the first engine of the plurality of units is stopped, When the supply amount of the high calorie fuel that rises due to the supply stop of the low calorie fuel in the first engine exceeds a predetermined threshold value, the engine is stopped after being driven for a predetermined time. Next, after stopping the supply of low calorie fuel to the second and subsequent engines that temporarily rises due to the supply stop of low calorie fuel to the first engine, the second engine is stopped according to the stop order of the remaining engines. In subsequent engines, when the supply amount of high-calorie fuel that rises due to the stop of supply of low-calorie fuel exceeds a predetermined threshold, the second and subsequent engines are driven for a certain period of time and then stopped sequentially. I have control.

  Due to this specific matter, when multiple engines are shut down, each engine is set to high calorie when the amount of high calorie fuel that rises due to the suspension of low calorie fuel supply to each engine exceeds a predetermined threshold. Since the fuel is driven for a certain period of time and then stopped, the mixed fuel is supplied to each engine as if each engine had been stopped with the mixed fuel of high-calorie fuel and low-calorie fuel supplied. There is no stopping while remaining, and after stopping for a certain period of time with only high calorie fuel, the remaining of mixed fuel (low calorie fuel) in each engine is canceled and the air-fuel ratio does not fluctuate at the start, It is possible to improve the startability of each engine with an appropriate air-fuel ratio. In addition, a large amount of water contained in the low calorie does not stay in each engine, and it is possible to realize a reliable start of each engine.

  Moreover, when the supply amount of low calorie fuel supplied from the low calorie fuel supply source has decreased, it is not necessary to increase the mixing ratio of the high calorie fuel in the mixed fuel to drive all of the engines. Only the number of engines corresponding to the degree of decrease in the amount of calorie fuel supplied will be driven, and the consumption of high calorie fuel can be reduced and a plurality of engines can be driven efficiently.

  Here, in the solution provided by the invention according to claim 5, the predetermined threshold value of each engine is gradually increased as it goes to the engine with the lower stop order.

  Due to this specific matter, the low-calorie fuel of the second and subsequent engines whose supply volume temporarily rises due to the stoppage of low-calorie fuel supply to the first engine after the first engine stops A predetermined threshold value that gradually increases as the engine goes to a slow engine ensures driving time using only high-calorie fuel, and the remaining low-calorie fuel that increases as the engine goes to a slow stop order is reliably eliminated, and each engine starts. Sometimes the air-fuel ratio does not fluctuate, and the startability of each engine with an appropriate air-fuel ratio can be improved more reliably. In addition, a large amount of water contained in the low calorie does not stay in each engine, and the startability of each engine can be realized more reliably.

  Further, in the solution means taken by the invention according to claim 6, while setting the target value of the throttle opening of the air supply path with respect to the driving load of the engine, the high calorie gas that generates a sufficient calorific value alone, In addition, when using a mixed gas mixed with a low calorie gas whose calorific value is insufficient and the calorific value itself varies with this high calorie gas alone, The supply amount of the low calorie gas is controlled so that the throttle opening degree of the air supply path correlated with the heat generation amount of the gas becomes the target value.

  Because of this specific matter, even if the engine driving load partially fluctuates, the amount of low calorie gas supplied is controlled so that the throttle opening of the air supply path becomes the target value. The mixed high-calorie fuel can cope with a partial driving load and keep the engine running.

  In the solution provided by the invention according to claim 7, the low calorie fuel is supplied to the engine in a heated state by heat exchange with the engine cooling water in the vicinity of the engine.

  Due to this specific matter, the low-calorie fuel is supplied to the engine in a heated state by heat exchange with the engine cooling water. Condensation water (moisture) mixed in low-temperature low-calorie fuel is heated and evaporated by heat exchange with water, and low-calorie fuel from which condensation water has been removed by evaporation is supplied to the engine in a heated state. Therefore, it is possible to reliably prevent engine misfire due to moisture in the low-calorie fuel, and to reliably prevent corrosion due to rust of the intake valve of the engine.

  Further, in the solution means taken by the invention according to claim 8, the lubricating oil of the engine is kept at a certain temperature or higher by heat exchange with the engine cooling water.

  Due to this specific matter, the engine lubricating oil is kept at a certain temperature or higher by heat exchange with the engine cooling water. Therefore, the air supply path is used to remove bubbles in the lubricating oil that accumulates in the oil pan at the bottom of the engine. Even if low-calorie fuel (mixed fuel) enters from the blow-by passage communicating with the fuel and water mixed in the low-calorie fuel is mixed in the lubricating oil, it is mixed by the lubricating oil kept above a certain temperature. The trapped water quickly evaporates, and it is possible to reliably prevent the generation of mayonnaise sludge of the lubricating oil due to the mixing of the water.

  In short, by starting the engine only with the high calorie fuel, it is possible to obtain an appropriate air-fuel ratio without greatly fluctuating only with the high calorie fuel, and to improve the startability of the engine. In addition, the low-calorie fuel can be actively used without causing misfire of the engine by mixing the low-calorie fuel with the high-calorie fuel after the engine driving load becomes a certain level or more after the engine is started.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a control system configuration diagram of a dual fuel engine according to Embodiment 1 of the present invention.

  In FIG. 1, 1 is a dual fuel engine, and 2 is a generator that is operated by the dual fuel engine 1.

  The dual fuel engine 1 is light oil as a high-calorie fuel that generates a sufficient calorific value by itself, and the calorific value is insufficient (for example, about 600 to 1000 kcal) by itself, and the calorific value itself fluctuates. A single engine is driven by a mixed fuel obtained by mixing fuel gas as a low calorie fuel.

  The fuel gas is generated from woody biomass such as thinned wood, pruned branches, building waste and cut grass in the fuel gas generation device X. As an example of the generation method, the fuel gas is obtained by burning fuel and air. After being decomposed into pyrolysis gas and solid residue by indirect heating under the air shutoff condition using the generated high-temperature combustion gas as the heat source, this pyrolysis gas contains air, oxygen-enriched air or oxygen After being introduced into the oxidant gas and causing a reaction between the combustible components contained in the pyrolysis gas and oxygen in the oxidant gas, the higher hydrocarbons in the pyrolysis gas are converted to lower hydrocarbons, etc. After the converted high-temperature gas is rapidly cooled, dust and harmful components contained in the gas are purified to obtain a fuel gas.

  The dual fuel engine 1 is based on a diesel engine, a fuel injection valve 3 for injecting light oil into the combustion chamber 1A, an air supply pipe 11 as an air supply path for supplying air to the combustion chamber 1A, and a combustion chamber 1A. An exhaust pipe 12 for exhausting the exhaust gas from the exhaust pipe, an exhaust temperature sensor 16 for detecting the temperature in the exhaust gas exhausted through the exhaust pipe 12, and an opening adjustment in the air supply pipe 11 so as to adjust the opening. A throttle valve 4 (throttle) for adjusting the supplied amount of the fuel gas, and a fuel gas introduction device for introducing the fuel gas generated in the fuel gas generation device X into the supply pipe 11 from the upstream side of the throttle valve 4 And 5. Reference numeral 14 denotes an oxidation catalyst device interposed in the exhaust pipe 12.

  The fuel injection valve 3 includes an injection pump 31 that supplies light oil to the fuel injection valve 3 and a rack 32 that adjusts the amount of light oil injected by the injection pump 31 to another stage. The rack 32 is connected to a controller 13 on which a CPU is mounted, and is controlled so as to move the rack 32 to a position where the injection amount of light oil by the injection pump 31 is optimally adjusted according to a command from the controller 13. doing.

  The throttle valve 4 is a butterfly type, and is connected to an opening adjustment mechanism 41 that adjusts the opening of the throttle valve 4. The opening adjustment mechanism 41 is connected to the controller 13. The exhaust temperature sensor 16 is also connected to the controller 13.

  The fuel gas introducing device 5 includes a fuel gas introducing tube 51 that guides the fuel gas generated by the fuel gas generating device X into the air supply tube 11 upstream of the throttle valve 4, and a fuel gas introducing tube 51 in the middle of the fuel gas introducing tube 51. An electromagnetic opening / closing valve 52 that is provided and opens / closes a middle position of the fuel gas introduction pipe 51, and is provided at a middle position of the fuel gas introduction pipe 51 downstream of the electromagnetic opening / closing valve 52, and detects the pressure of the fuel gas. Gas pressure sensor 54 and a fuel gas introduction pipe 51 provided downstream of the gas pressure sensor 54, and the pressure of the fuel gas supplied from the fuel gas introduction pipe 51 to a mixer 56 (described later) A constant regulator 55 and a fuel gas introduced into the air supply pipe 11 through the fuel gas introduction pipe 51 are provided in the middle of the air supply pipe 11 where the downstream end of the fuel gas introduction pipe 51 is opened. A mixer 56 to be mixed with the air inside, and an A / F valve that is provided between the regulator 55 and the mixer 56 and adjusts the amount of fuel gas supplied to the mixer 56 held at a constant gas pressure by the regulator 55 59. The opening adjustment mechanism 41 of the throttle valve 4, the electromagnetic on-off valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 are connected to the controller 13. Is controlled so that an optimal amount of fuel gas is led from the fuel gas introduction pipe 51 through the air supply pipe 11 to the combustion chamber 1A. Further, the electromagnetic on-off valve 52 is of an on-off switching type, and only a small amount of fuel gas is introduced into the fuel gas introduction pipe 51 unless the A / F valve 59 is adjusted to be open even when switched to an open state. It is configured as follows. In this case, when the dual fuel engine 1 (engine) is driven by a mixed fuel of light oil and fuel gas, the flow rate of light oil is adjusted by adjusting the position of the rack 32, the opening of the throttle valve 4 is adjusted, and the fuel gas introduction device 5 (A / The flow rate of the fuel gas is controlled by the F valve 59).

  As a feature of the present invention, when the dual fuel engine 1 is started, the engine is started only with light oil, and then the fuel gas is mixed with the light oil after the driving load of the engine exceeds a certain level. In addition, the supply amount of the fuel gas is controlled by the A / F valve 59. As shown in FIG. 2, the target value of the engine speed is PID controlled to determine the position of the rack 32, and the injection amount (supply amount) is adjusted by the determined rack 32 position, as shown in FIG. The light oil thus supplied is supplied to the engine (combustion chamber 1A) of the dual fuel engine 1. When the driving load of the engine exceeds a certain value, that is, starts to increase (act), the opening adjustment mechanism 41 of the throttle valve 4, the electromagnetic on-off valve 52 of the fuel gas introduction device 5, the gas pressure sensor 54, and the A / F valve 59 are turned on. As the fuel gas is guided from the fuel gas introduction pipe 51 to the combustion chamber 1A through the air supply pipe 11 under the control of the controller 13, the fuel gas starts to be supplied to the light oil. At this time, the position of the rack 32 is also changed so as to increase the supply amount of the light oil, the opening degree of the A / F valve 59 is determined based on the changed position of the rack 32, and the determined A / F valve 59 is determined. Is supplied to the engine of the dual fuel engine 1 (combustion chamber 1A).

  When the single engine of the dual fuel engine 1 is stopped, before the engine is stopped, the opening adjustment mechanism 41 of the throttle valve 4, the electromagnetic on-off valve 52 of the fuel gas introduction device 5, the gas pressure sensor 54, and The A / F valve 59 is controlled by the controller 13 to stop the supply of the fuel gas introduced from the fuel gas introduction pipe 51 into the combustion chamber 1A via the air supply pipe 11, that is, the supply of the fuel gas mixed with the light oil After the engine is stopped, the engine is driven only for light oil, and then the rack 32 position is changed to stop the engine so that the supply amount of light oil is stopped.

  Specifically, as shown in FIG. 3, when a stop signal is output from the controller 13 to the fuel gas introduction device 5 when stopping a single engine of the dual fuel engine 1, the electromagnetic on-off valve 52 is closed, At a time T2 when a predetermined time (for example, about 10 seconds) has elapsed from the time T1 (output time of the stop signal), the supply of the fuel gas from the fuel gas introduction pipe 51 to the combustion chamber 1A via the air supply pipe 11 is prohibited. Close the A / F valve 59. In addition, the rack 32 position is also changed so that the amount of light oil supplied is reduced at the time T1 when the stop signal is output to the fuel gas introduction device 5, and at a time T2 when a predetermined time has elapsed from the time T1 when the stop signal is output. After changing the position of the rack 32 so as to reduce the supply amount slowly and after the engine driving load is no longer generated, the position of the rack 32 is changed so as to keep the supply amount of light oil constant (decrease value). Stop supplying. At this time, the single unit of the dual fuel engine 1 is between the time T2 when a predetermined time has elapsed from the output time T1 of the stop signal and the time until a certain time (for example, 20 and several seconds) elapses between the time when the light oil supply amount is stopped. One engine will be driven by light oil only.

  Further, as shown in FIG. 1, at the bottom of the engine of the dual fuel engine 1, lubricating oil that flows through the lubricating oil passage 101 of the engine, and cooling water (engine cooling water) that flows through the cooling water passage 102 that cools the engine, A heat exchanger 103 that performs heat exchange between the two is provided. The engine lubricating oil is heat-exchanged with the cooling water by the heat exchanger 103 and heated, and is kept at a certain temperature (for example, 70 ° C.) or higher. The oil pan at the bottom of the engine is provided with a blow-by passage (not shown) that communicates with the air supply pipe 11 in order to remove bubbles in the lubricating oil accumulated in the oil pan.

  Therefore, in the first embodiment, since the engine is started only by light oil when starting the single engine of the dual fuel engine 1, the engine is started by the mixed fuel of light oil and fuel gas. In addition, the total calorific value of the mixed fuel does not fluctuate greatly, and an appropriate air-fuel ratio is obtained only by light oil. In addition, since the fuel gas supply to the engine is stopped when the single engine of the dual fuel engine 1 is stopped, the engine is stopped by driving the engine for a certain period of time using only light oil. The mixed fuel does not stop while remaining in the engine as if the engine had been stopped with the mixed fuel being supplied. The remaining fuel (fuel gas) is eliminated and the air-fuel ratio does not fluctuate at the start. Thereby, the startability of the engine can be improved with an appropriate air-fuel ratio.

  In addition, after stopping the supply of fuel gas to the engine, the engine is stopped only by light oil for a certain period of time, and then the engine is stopped, so that a large amount of water contained in the fuel gas does not stay in the engine. A reliable start can be realized.

  Further, since the fuel gas is mixed with the light oil after the engine driving load starts to increase (act) after the engine is started, the fuel gas can be actively used without causing misfire of the engine.

  Further, since the lubricating oil of the engine is heat-exchanged with the cooling water by the heat exchanger 103 so as to be maintained at a certain temperature (for example, 70 ° C.) or more, the bubbles in the lubricating oil collected in the oil pan at the bottom of the engine Even if fuel gas (mixed fuel) enters from the blow-by passage that communicates with the air supply path in order to remove air and water mixed in the fuel gas is mixed into the lubricating oil, the temperature is kept above a certain temperature. Moisture mixed in the lubricating oil quickly evaporates, and generation of mayonnaise sludge of the lubricating oil due to the mixed water can be reliably prevented.

  Next, a second embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, a single engine of the dual fuel engine 6 is driven by a mixed gas of city gas and fuel gas instead of light oil. In addition, the same code | symbol is attached | subjected about the part same as the said Example 1, and the detailed description is abbreviate | omitted.

  That is, in this embodiment, as shown in FIG. 4, the dual fuel engine 6 is based on a gas engine, and an air supply pipe 61 as an air supply path for supplying air to the combustion chamber 6 </ b> A and a high calorie gas Of the city gas is introduced into the supply pipe 61 from the upstream side of the throttle valve 4, the ignition coil 68 for igniting the ignition plug 67 of the combustion chamber 6A, and the exhaust gas for exhausting the exhaust gas from the combustion chamber 6A. A pipe 62, an exhaust temperature sensor 66 for detecting the temperature in the exhaust gas exhausted through the exhaust pipe 62, and an opening in the air supply pipe 61 are adjustable so that the air, fuel gas and city gas are mixed. The throttle valve 4 for adjusting the supply amount of the mixed gas and the fuel gas generated in the fuel gas generator X from the upstream side of the throttle valve 4 into the supply pipe 61 And a fuel gas introduction unit 5 for input.

  The city gas introduction device 60 includes a city gas introduction pipe 601 that guides city gas from a city gas drawing pipe (not shown) drawn into the site into the air supply pipe 61 upstream of the throttle valve 4; An electromagnetic on-off valve 602 that is provided in the middle of the city gas introduction pipe 601 and opens and closes the middle position of the city gas introduction pipe 601, and an intermediate position of the city gas introduction pipe 601 on the downstream side of the electromagnetic on-off valve 602. A gas pressure sensor 604 that detects the pressure of the city gas, and is provided in the middle of the city gas introduction pipe 601 on the downstream side of the gas pressure sensor 604, and the city gas supplied from the city gas introduction pipe 601 A regulator 605 for keeping the pressure constant, and between the regulator 605 and the mixer 56 of the fuel gas introduction device 5 are maintained at a constant gas pressure by the regulator 605. And a A / F valve 609 for adjusting the supply amount of the city gas, which is. The downstream end of the city gas introduction pipe 601 opens to the mixer 56 (air supply pipe 61) of the fuel gas introduction apparatus 5, and the mixer 56 introduces the gas gas into the air supply pipe 61 via the city gas introduction pipe 601. The city gas and the fuel gas introduced into the air supply pipe 61 through the fuel gas introduction pipe 51 are mixed with the air in the air supply pipe 61. Further, the opening adjustment mechanism 41 of the throttle valve 4, the electromagnetic on-off valve 602, the gas pressure sensor 604, and the A / F valve 609 of the city gas introduction device 60 are connected to the controller 13. Is controlled so that an optimal amount of city gas is led from the city gas introduction pipe 601 through the air supply pipe 61 to the combustion chamber 6A. Further, the electromagnetic on-off valve 602 is of an open / close switching type, and only a small amount of city gas is introduced into the city gas introduction pipe 601 as long as the A / F valve 609 is not adjusted to open even if the electromagnetic on-off valve 602 is switched to the open state. It is configured as follows. In this case, when the dual fuel engine 6 is driven by a mixed gas of city gas and fuel gas, the city gas flow rate control by the city gas introduction device 60 (A / F valve 609), the opening degree adjustment of the throttle valve 4, and The fuel gas flow rate is controlled by the fuel gas introduction device 5 (A / F valve 59).

  The ignition coil 68 is for igniting a mixed gas obtained by mixing air with city gas and fuel gas by the mixer 56 with an ignition plug 67, and is connected to the controller 13.

  As a feature of the present invention, when starting a single engine of the dual fuel engine 6, the engine is started only with city gas. Thus, the fuel gas supply amount is controlled by the A / F valve 59 so that the fuel gas is mixed. As shown in FIG. 5, as shown in FIG. 5, the target position of the engine speed is PID controlled to determine the opening position of the throttle valve 4, and the flow rate is adjusted by the determined opening position. City gas is supplied to the dual fuel engine 6 (combustion chamber 6A). When the driving load of the engine exceeds a certain value, that is, starts to increase (act), the opening adjustment mechanism 41 of the throttle valve 4, the electromagnetic on-off valve 52 of the fuel gas introduction device 5, the gas pressure sensor 54, and the A / F valve 59 are turned on. As the fuel gas is guided from the fuel gas introduction pipe 51 to the combustion chamber 6A through the air supply pipe 61 under the control of the controller 13, the fuel gas starts to be supplied to the city gas. At this time, the opening degree of the A / F valve 609 is also changed so as to increase the supply amount of city gas, and the opening degree of the A / F valve 59 is determined based on the changed opening degree of the A / F valve 609. The fuel gas whose supply amount is adjusted by the determined opening degree of the A / F valve 59 is supplied to the engine (combustion chamber 6A) of the dual fuel engine 6.

  When the single engine of the dual fuel engine 6 is stopped, before the engine is stopped, the opening adjustment mechanism 41 of the throttle valve 4, the electromagnetic on-off valve 52 of the fuel gas introduction device 5, the gas pressure sensor 54, and The A / F valve 59 is controlled by the controller 13 to stop the supply of the fuel gas introduced into the combustion chamber 6A from the fuel gas introduction pipe 51 through the air supply pipe 61, that is, the fuel gas mixed with the city gas After the supply is stopped, the electromagnetic on-off valve 602, the gas pressure sensor 604, and the A / F valve of the city gas introduction device 60 are stopped so that the supply amount of the city gas is stopped after the engine is driven only by the city gas for a certain period of time. 609 is controlled by the controller 13 to stop the supply of the fuel gas introduced into the combustion chamber 6A from the city gas introduction pipe 601 through the air supply pipe 61 and And it is controlled so as to locked.

  Specifically, as shown in FIG. 6, when a stop signal is output from the controller 13 to the fuel gas introduction device 5 when stopping a single engine of the dual fuel engine 1, the electromagnetic on-off valve 52 is closed, The supply of fuel gas from the fuel gas introduction pipe 51 to the combustion chamber 6A via the air supply pipe 61 is prohibited at a time T2 when a predetermined time (for example, about 10 seconds) has elapsed from the time T1 (output time of the stop signal). Close the A / F valve 59. Further, the A / F valve 609 is adjusted so that the supply amount of the city gas is decreased at the output time T1 of the stop signal to the fuel gas introducing device 5, and at a time T2 when a predetermined time has elapsed from the output time T1 of the stop signal. The A / F valve 609 is adjusted so as to reduce the city gas supply amount slowly, and after the engine driving load is no longer generated, the city gas supply amount is kept constant (decreased value). After adjusting the / F valve 609, the electromagnetic on-off valve 52 is closed to stop the supply of city gas. At this time, the single unit of the dual fuel engine 1 is not changed until a certain time (for example, 20 or more seconds) elapses between a time T2 when a predetermined time has elapsed from the output time T1 of the stop signal and a time when the supply amount of light oil is stopped. One engine will be powered by city gas only.

  Further, as shown in FIG. 7, a target value of the opening degree of the throttle valve 4 of the air supply pipe 61 with respect to the engine driving load is set, and the heat generation of the fuel gas occurs when the engine driving load partially fluctuates. The A / F valve 59 is controlled by the controller 13 so that the opening degree of the throttle 4 valve of the air supply pipe 61 having a correlation with the amount becomes a target value, and the combustion chamber is supplied from the fuel gas introduction pipe 51 through the air supply pipe 61. The supply amount of the fuel gas introduced into 6A is adjusted.

  Further, as shown in FIG. 8, in the vicinity of the engine of the dual fuel engine 6, heat exchange is performed between the coolant flowing through the coolant passage 71 that cools the engine and the fuel gas supplied to the engine from the supply pipe 61. There is provided a heat exchanger 72 for performing the above. The heat exchanger 72 includes a chamber 72a that covers the periphery of the air supply pipe 61 in the vicinity of the engine. An inlet 72b for introducing engine cooling water introduced from the engine into the chamber 72a is provided at the downstream side of the air supply pipe 61 of the chamber 72a, while at the upstream side of the air supply pipe 11 of the chamber 72a, A discharge port 72c for discharging the engine cooling water introduced into the chamber 72a is provided. The fuel gas flowing in the air supply pipe 61 is supplied to the engine while being heated by heat exchange with the engine cooling water in the vicinity of the engine by the heat exchanger 72. In addition, a U-shaped tube 73 that curves downward is interposed at a midway position of the air supply tube 61 that is located upstream of the heat exchanger 72. At the lower portion of the U-shaped tube 73, a drain cock 73 a that discharges moisture accumulated in the U-shaped tube 73 to the outside of the U-shaped tube 73 is provided. In this case, the air supply pipes 61 on the upstream side and the downstream side of the U-shaped pipe 73 are respectively provided with gradients so as to accumulate moisture in the pipe with respect to the U-shaped pipe 73.

  Therefore, in the second embodiment, since the engine is started only by the city gas when starting the single engine of the dual fuel engine 1, the engine is started by the mixed gas of the city gas and the fuel gas. The total calorific value of the mixed gas does not fluctuate greatly as in the case of the thing, and an appropriate air-fuel ratio is obtained only by the city gas. In addition, since the fuel gas supply to the engine is stopped when the single engine of the dual fuel engine 1 is stopped, the engine is stopped only by driving the engine for a certain period of time using only the city gas. The engine does not stop with the mixed gas remaining in the engine as if the engine had been stopped with the mixed gas supplied with the fuel gas. The remaining of the mixed gas (fuel gas) is eliminated and the air-fuel ratio does not change at the start. Thereby, the startability of the engine can be improved with an appropriate air-fuel ratio.

  In addition, after stopping the supply of fuel gas to the engine, by driving the engine for a certain time only with city gas and then stopping the engine, a large amount of water contained in the fuel gas will not stay in the engine, A reliable start of the engine can be realized.

  Further, since the fuel gas is mixed with the city gas after the engine driving load starts to increase (act) after the engine is started, the fuel gas can be actively used without causing misfire of the engine.

  In addition, even if the driving load of the engine partially fluctuates, the fuel gas supply amount is controlled by the A / F valve 59 so that the opening degree of the throttle valve 4 of the air supply pipe 61 becomes the target value. The city gas mixed at a constant mixing ratio can cope with a partial driving load and continue to drive the engine.

  Further, a heat exchanger 72 for exchanging heat between the cooling water flowing in the cooling water passage 71 and the fuel gas supplied to the engine from the air supply pipe 61 is provided in the vicinity of the engine of the dual fuel engine 6. Since it is supplied to the engine in a heated state by heat exchange with the engine cooling water, it is driven in the low temperature fuel gas by heat exchange with the engine cooling water that has become hot because it is driven only by light oil when starting the engine. Condensed water (water) mixed in the fuel is heated and evaporated, and the fuel gas from which the condensed water has been removed by evaporation is supplied to the engine in a heated state. Misfires can be reliably prevented, and corrosion due to rust of the intake valve of the engine can be reliably prevented. In addition, since the U-shaped tube 73 is interposed in the middle of the air supply tube 61 located on the upstream side of the heat exchanger 72, moisture mixed in the mixed fuel (fuel gas) is removed from the U-shaped tube 73. The upstream and downstream air supply pipes 61 are guided by the gradient of the air supply pipe 61 and accumulated in the U-shaped pipe 73, and the water accumulated in the U-shaped pipe 73 is periodically removed from the U-shaped pipe 73 by the drain cock 73a. The moisture in the air supply pipe 61 can be effectively eliminated.

  Next, Embodiment 3 of the present invention will be described with reference to FIGS.

  In this embodiment, a plurality of engines of the dual fuel engine 8 are driven by a mixed gas of light oil and fuel gas. In addition, the same code | symbol is attached | subjected about the part same as the said Example 1, and the detailed description is abbreviate | omitted.

  That is, in the present embodiment, as shown in FIG. 9, the dual fuel engine 8 drives the six first to sixth engines 8a to 8f by the mixed fuel obtained by mixing light oil and fuel gas, respectively. It is configured. In addition, each engine 8a-8f is the same structure, and is each connected with the fuel gas production | generation apparatus X by the branch part of the supply pipe 81 (after-mentioned).

  As shown in FIG. 10, each engine 8a to 8f of the dual fuel engine 8 includes a fuel injection valve 3 for individually injecting light oil into the combustion chamber 8A of each engine 8a to 8f, and each engine 8a to 8f. An air supply pipe 81 serving as an air supply path that branches from the combustion chamber 8A and supplies air, an exhaust pipe 82 that collects exhaust gas from the combustion chambers 8A of the engines 8a to 8f, and exhausts the exhaust, respectively. An exhaust temperature sensor 86 for detecting the temperature in the exhaust gas discharged through the exhaust pipe, and a throttle for adjusting the supply amount of the fuel gas mixed with air, provided at the respective branch portions of the supply pipe 81 so that the opening degree can be adjusted. A fuel gas introduction device 5 for individually introducing the fuel gas produced in the fuel gas production device X into the branch portion of the supply pipe 81 from the upstream side of the throttle valve 4; It is provided. Reference numeral 84 denotes an oxidation catalyst device interposed in the exhaust pipe 82 on the downstream side of each branch portion of the air supply pipe 81.

  The fuel gas introduction pipe 51 of the fuel gas introduction apparatus 5 guides the fuel gas generated by the fuel gas generation apparatus X into the branch portion of the supply pipe 81 upstream of the throttle valve 4. The mixer 56 is provided in the middle of the branch portion of the air supply pipe 81 where the downstream end of the fuel gas introduction pipe 51 is open, and the fuel introduced into the branch portion of the air supply pipe 81 via the fuel gas introduction pipe 51. The gas is mixed with the air in the branch portion of the supply pipe 81. The opening adjustment mechanism 41 of the throttle valve 4 of each engine 8a to 8f, the electromagnetic on-off valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 are connected to the controller 13. In accordance with a command from the controller 13, an optimal amount of fuel gas is controlled to be led from the fuel gas introduction pipe 51 to the combustion chamber 8 </ b> A via the branch portion of the air supply pipe 81. In this case, when the dual fuel engine 8 is driven by a mixed fuel of light oil and fuel gas, the flow rate of light oil is adjusted by adjusting the position of the rack 32 for each engine 8a to 8f, the opening adjustment of the throttle valve 4, and the fuel gas introduction device. 5 (A / F valve 59) controls the flow rate of the fuel gas. Further, when the rotational speed and driving load of each engine 8a to 8f are constant, the supply amount of light oil, that is, the position of the rack 32, which is correlated with the calorific value of the fuel gas is controlled.

  As a feature of the present invention, when starting the engines 8a to 8f of the dual fuel engine 8, the first first engine 8a is started only with light oil, and the driving load of the first engine 8a is After reaching a certain level, the first engine 8a is continuously driven by the mixed fuel obtained by mixing the fuel gas with the light oil. Next, when the mixing ratio of the light oil in the mixed fuel driving the first engine 8a reaches a predetermined value or less, the second second engine 8b is started only with the light oil, and this second engine 8b is started. The second engine 8b is continuously driven by the mixed fuel obtained by mixing the fuel gas with the light oil. Thereafter, when the mixing ratio of light oil in the mixed fuel driving the second engine 8b reaches a predetermined value or less, the subsequent third to sixth engines 8c to 8f are sequentially started according to the above procedure. Is controlling.

  Specifically, as shown in FIG. 11, the target value of the rotational speed of the first engine 8a is PID controlled to determine the position of the rack 32, and the injection amount (supply amount) is determined by the determined rack 32 position. The adjusted light oil is supplied to the first engine 8a (combustion chamber 8A), and driving of the first engine 8a using only light oil is started. Then, when a predetermined time T3 (for example, tens of seconds) elapses after the driving load of the first engine 8a increases and becomes a constant value, the opening adjustment mechanism 41 of the throttle valve 4 and the electromagnetic opening / closing valve 52 of the fuel gas introduction device 5 The gas pressure sensor 54 and the A / F valve 59 are controlled by the controller 13 so that the fuel gas is led from the fuel gas introduction pipe 51 to the combustion chamber 8A through the branch portion of the supply pipe 81 of the first engine 8a. The fuel gas starts to be supplied to the diesel oil. At this time, when the fuel gas starts to be supplied, the position of the rack 32 is also changed so as to reduce the supply amount of the light oil to a certain value, and the opening degree of the A / F valve 59 is set based on the changed position of the rack 32. The fuel gas whose supply amount is adjusted by the determined opening degree of the A / F valve 59 is supplied to the first engine 8a (combustion chamber 8A).

  Next, when the mixing ratio of the light oil in the mixed fuel driving the first engine 8a reaches a predetermined value or less, the rack 32 determined by PID control of the target value of the rotational speed of the first engine 8a. The light oil whose injection amount (supply amount) is adjusted according to the position is supplied to the second engine 8b (combustion chamber 8A), and the driving of the second engine 8b using only light oil is started. Then, when a predetermined time T3 (for example, several tens of seconds) elapses after the driving load of the second engine 8b increases and becomes a constant value, the opening adjustment mechanism 41 of the throttle valve 4 and the electromagnetic opening / closing valve 52 of the fuel gas introduction device 5 The gas pressure sensor 54 and the A / F valve 59 are controlled by the controller 13 so that the fuel gas is guided from the fuel gas introduction pipe 51 to the combustion chamber 8A through the branch portion of the air supply pipe 81 of the second engine 8b. The fuel gas starts to be supplied to the diesel oil. At this time, when the fuel gas starts to be supplied, the position of the rack 32 is also changed so as to reduce the supply amount of the light oil to a certain value, and the opening degree of the A / F valve 59 is set based on the changed position of the rack 32. The fuel gas whose supply amount is adjusted by the determined opening degree of the A / F valve 59 is supplied to the second engine 8b (combustion chamber 8A).

  Thereafter, when the mixing ratio of the light oil in the mixed fuel driving the second engine 8b reaches a certain value or less, the subsequent third to sixth engines 8c to 8f (combustion chamber 8A) are operated as described above. The control is performed so as to start sequentially.

  Further, when the supply amount of the fuel gas supplied from the fuel gas generator X to the respective engines 8a to 8f of the dual fuel engine 8 decreases, the first engine 8a that stops at the beginning of the six engines 8a to 8f. When the fuel gas supply to the engine is stopped and the supply amount of light oil that rises as the fuel gas supply stops in the first engine 8a exceeds a predetermined threshold value, the first engine 8a is driven for a predetermined time. Stop after letting go. Next, the fuel to the second second engine 8b that temporarily rises due to the stop of the supply of the fuel gas to the first engine 8a, that is, the stop of the supply of the fuel gas to the branch portion of the supply pipe 81 of the first engine 8a. After the gas supply is stopped, the second engine 8b is driven for a certain period of time when the supply amount of light oil that rises as the fuel gas supply stops in the second engine 8b exceeds a predetermined threshold value. Control to stop. In the third to sixth engines 8c to 8f, which are sequentially stopped thereafter, the supply of fuel gas to the second engine 8b is stopped, that is, the supply of fuel gas to the branch portion of the supply pipe 81 of the second engine 8b is stopped. After the supply of fuel gas to the third to sixth engines 8c to 8f, which rises temporarily due to the supply stop, is stopped according to the stop order of the remaining third to sixth engines 8c to 8f, the three engines The third to sixth engines 8c after the third unit when the supply amount of light oil that rises as the fuel gas supply stops in the third to sixth engines 8c to 8f after the first exceeds a predetermined threshold value. ˜8f is controlled to be sequentially stopped after being driven for a certain time.

  Specifically, as shown in FIG. 12, when the supply amount of the fuel gas supplied from the fuel gas generator X to the engines 8a to 8f of the dual fuel engine 8 decreases, the six engines 8a to 8 The controller 13 controls the opening adjustment mechanism 41 of the throttle valve 4 of the first engine 8a that stops first in 8f, the electromagnetic on-off valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 to control the fuel. The supply of the fuel gas introduced from the gas introduction pipe 51 into the combustion chamber 8A of the first engine 8a through the branch portion of the supply pipe 81 is stopped, that is, the supply of the fuel gas mixed with the light oil is stopped. At this time, the position of the rack 32 is changed as the fuel gas supply is stopped in the first engine 8a, and the supply amount of the light oil is increased. When the supply amount of the light oil exceeds a predetermined threshold value S1, the supply of the light oil is performed. The position of the rack 32 is changed so as to reduce the amount, and the position of the rack 32 is changed so that the supply amount of the light oil is maintained at a constant value (minimum value) when the driving load of the first engine 8a stops working. Then, the first engine 8a is stopped. In this case, the constant between the time when the position of the rack 32 is changed so as to decrease the supply amount of light oil after the supply amount of light oil exceeds a predetermined threshold S1 and the time when the supply amount of light oil is stopped. Until the time elapses, the first engine 8a is driven only by light oil.

  Next, the fuel gas supply to the second second engine 8b, which temporarily rises due to the supply stop of the fuel gas to the first engine 8a, is the opening adjustment mechanism of the throttle valve 4 of the second engine 8b. 41. The controller 13 controls the electromagnetic open / close valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 to stop. At this time, in the second engine 8b, the position of the rack 32 is changed with the stop of the supply of fuel gas, the supply amount of light oil increases, and the supply of light oil is increased when the supply amount of light oil exceeds a predetermined threshold value S2. The position of the rack 32 is changed so as to reduce the amount, and the position of the rack 32 is changed so that the supply amount of the light oil is maintained at a constant value (minimum value) when the driving load of the second engine 8b stops working. Then, the second engine 8b is stopped. In this case, there is a constant interval between the time when the position of the rack 32 is changed so as to decrease the supply amount of light oil after the supply amount of light oil exceeds a predetermined threshold S2 and the time when the supply amount of light oil is stopped. Until the time elapses, the second engine 8b is driven only by light oil.

  After that, the fuel gas supply to the third third engine 8c, which temporarily rises due to the stop of the supply of fuel gas to the second engine 8b, is the opening adjustment mechanism of the throttle valve 4 of the third engine 8c. 41. The controller 13 controls the electromagnetic open / close valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 to stop. At this time, when the supply of fuel gas is stopped in the third engine 8c, the position of the rack 32 is changed and the amount of light oil supplied rises, and the amount of light oil supplied exceeds a predetermined threshold (not shown). The position of the rack 32 is changed so that the supply amount of the light oil is reduced, and the supply amount of the light oil is held at a constant value (minimum value) when the driving load of the third engine 8c stops working. After the change, the third engine 8c is stopped.

  Then, the fuel gas supply to the fourth fourth engine 8d, which temporarily rises due to the supply stop of the fuel gas to the third engine 8c, is the opening adjustment mechanism of the throttle valve 4 of the fourth engine 8d. 41. The controller 13 controls the electromagnetic open / close valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 to stop. At this time, as shown in FIG. 13, in the fourth engine 8d, the position of the rack 32 is changed in accordance with the stop of the supply of fuel gas, and the supply amount of light oil increases, and the supply amount of light oil reaches a predetermined threshold value S4. The position of the rack 32 is changed so as to decrease the supply amount of light oil when it exceeds the upper limit, and the supply amount of light oil is held at a constant value (minimum value) when the driving load of the fourth engine 8d stops working. After changing the position of the rack 32, the fourth engine 8d is stopped.

  Thereafter, the supply of fuel gas to the fifth fifth engine 8e, which temporarily rises due to the stop of the supply of fuel gas to the fourth engine 8d, is adjusted to adjust the opening of the throttle valve 4 of the fifth engine 8e. The mechanism 41, the electromagnetic on-off valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 are controlled by the controller 13 and stopped. At this time, in the fifth engine 8e, the position of the rack 32 is changed with the stop of the supply of fuel gas, the supply amount of light oil increases, and the supply of light oil is increased when the supply amount of light oil exceeds a predetermined threshold value S5. The position of the rack 32 is changed so as to reduce the amount, and the position of the rack 32 is changed so that the supply amount of the light oil is held at a constant value (minimum value) when the driving load of the fifth engine 8e stops working. Then, the fifth engine 8e is stopped.

  Finally, the supply of the fuel gas to the sixth sixth engine 8f, which temporarily rises due to the stop of the supply of the fuel gas to the fifth engine 8e, is the opening of the throttle valve 4 of the sixth engine 8f. The adjustment mechanism 41, the electromagnetic on-off valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 are controlled by the controller 13 and stopped. At this time, the position of the rack 32 is changed as the fuel gas supply is stopped in the sixth engine 8f, and the supply amount of the light oil is increased. When the supply amount of the light oil exceeds a predetermined threshold value S6, the supply of the light oil is performed. The rack 32 position is changed so that the amount is maintained at a constant value (the maximum value in the ascending process), and after a predetermined time has elapsed, the rack 32 position is changed so as to reduce the amount of light oil supplied, and the sixth engine 8f. The sixth engine 8f is stopped after changing the rack 32 position so that the supply amount of the light oil is maintained at a constant value (minimum value) when the driving load no longer acts.

  In this case, as shown in FIG. 14, the predetermined threshold values S1 to S6 (excluding S3) of the first to sixth engines 8a to 8f are gradually increased as the engine goes to the engine with the lower stop order. This is because the number of engines distributed to the combustion chambers 8A of the respective engines 8a to 8f through the branch portion of the supply pipe 81 gradually decreases due to a decrease in the fuel gas from the fuel gas generation device X, and the distribution thereof. This is because the supply amount of light oil required to finish combustion without leaving the fuel gas whose supply amount temporarily increases in the supply pipe 81 (branch portion) as the number of engines to be reduced increases.

  Therefore, in the third embodiment, the engines 8a to 8f are started only by light oil when the six first to sixth engines 8a to 8f are started. Therefore, the mixed fuel of light oil and fuel gas is used for the engine. The total calorific value of the mixed fuel does not fluctuate greatly as in the case where the engine is started, and an appropriate air-fuel ratio is obtained only by light oil. In addition, when the engines 8a to 8f are stopped, the amount of light oil that rises as the fuel gas supply from the fuel gas generator X to the engines 8a to 8f is stopped exceeds a predetermined threshold value S1 to S6. Sometimes, the engines 8a to 8f are driven only for light oil for a certain period of time and then stopped, so mixing is performed as if the engines were stopped with a fuel mixture of light oil and fuel gas supplied. The fuel is not stopped while remaining in each engine 8a to 8f, and the engine is stopped after being driven for a certain time by using only light oil, and the remaining of the mixed fuel (fuel gas) in each engine 8a to 8f is eliminated. Sometimes the air / fuel ratio does not fluctuate. Thereby, the startability of each engine 8a-8f by an appropriate air fuel ratio can be improved. In addition, a large amount of water contained in the fuel gas does not stay in the engines 8a to 8f, and the engines 8a to 8f can be reliably started.

  In addition, when the engines 8a to 8f are started, the driving load of the first engine 8a is increased after the first first engine 8a is started, and after a predetermined time T3 (for example, several tens of seconds) has passed, On the other hand, the fuel gas is mixed, and when the mixing ratio of the light oil in the mixed fuel reaches a predetermined value or less, the subsequent second to sixth engines 8b to 8f are sequentially started. Six first to sixth engines 8a to 8f are started one by one in accordance with the amount of fuel gas supplied from the generator X, and each engine is started at the same time when a plurality of engines are started. As in the case where the amount of fuel gas supplied is small, the mixing ratio of light oil in the mixed fuel is not inadvertently increased, and the consumption of light oil is reduced without causing misfire of each engine 8a to 8f. Fuel gas efficiently and actively It can be used.

  Further, when the supply amount of the fuel gas supplied from the fuel gas generation device X has decreased, it is not necessary to drive all the six engines 8a to 8f by increasing the mixing ratio of light oil in the mixed fuel, Only the number of engines corresponding to the degree of decrease in the supply amount of the fuel gas is driven, so that the consumption of light oil can be reduced and the six engines 8a to 8f can be driven efficiently.

  Further, since the predetermined threshold values S1 to S6 of the respective engines 8a to 8f are gradually increased as the engine goes to the engine having the lower stop order, the fuel to the first engine 8a is stopped after the first first engine 8a is stopped. The fuel gas of the second to sixth engines 8b to 8f, whose supply amount temporarily rises due to the stop of gas supply, gradually increases as the fuel gas of the second to sixth engines 8b to 8f goes to the engine with the lower stop order. As a result, the remaining fuel gas that increases as the engine goes to a slow stop order is reliably eliminated, and the air-fuel ratio does not fluctuate when the engines 8a to 8f are started. The startability of 8a-8f can be improved more reliably. In addition, a large amount of water contained in the fuel gas does not stay in each engine 8a to 8f, and the startability of each engine 8a to 8f can be more reliably realized.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, a plurality of engines of the dual fuel engine 1 are driven by a mixed gas of city gas and fuel gas. In addition, the same code | symbol is attached | subjected about the part same as the said Example 3, and the detailed description is abbreviate | omitted.

  That is, in this embodiment, as shown in FIG. 15, the dual fuel engine 9 drives the six first to sixth engines 9 a to 9 f by the mixed gas obtained by mixing the city gas and the fuel gas. It is configured as follows. In addition, each engine 9a-9f is the same structure, and is each connected with the fuel gas production | generation apparatus X by the branch part of the air supply pipe | tube 91 (after-mentioned).

  As shown in FIG. 16, each engine 9a-9f of the dual fuel engine 9 branches to the combustion chamber 9A of each engine 9a-9f, and an air supply pipe 91 as an air supply path for supplying air, respectively, A city gas introduction device 60 for introducing city gas as caloric fuel into each branch portion of the supply pipe 91 from the upstream side of the throttle valve 4, an ignition coil 98 for igniting the ignition plug 97 of the combustion chamber 9A, and each engine An exhaust pipe 92 that collects exhaust gases 9a to 9f and exhausts exhaust gas, an exhaust temperature sensor 96 that detects the temperature in the exhaust exhausted through the exhaust pipe 92, and a branch of the supply pipe 91 The throttle valve 4 is provided in each part so that the opening degree can be adjusted, and adjusts the supply amount of the mixed gas obtained by mixing air, fuel gas, and city gas, and the fuel gas generating device X. The fuel gas produced Te and a fuel gas introduction device 5 for respectively introduced into each branch portion of the supply pipe 91 from the upstream side of the throttle valve 4.

  The city gas introduction device 60 guides city gas from a city gas inlet pipe (not shown) drawn into the site into each branch portion of the supply pipe 91 upstream of the throttle valve 4. An introductory pipe 601, an electromagnetic on-off valve 602 that is provided in the middle of the city gas introduction pipe 601, and opens and closes a midway position of the city gas introduction pipe 601, and a city gas introduction pipe on the downstream side of the electromagnetic on-off valve 602 A gas pressure sensor 604 for detecting the pressure of the city gas provided in the middle of 601 and a city gas introduction pipe 601 on the downstream side of the gas pressure sensor 604 are provided and supplied from the city gas introduction pipe 601. A regulator 605 for keeping the pressure of the city gas to be constant, and between the regulator 605 and the mixer 56 of the fuel gas introduction device 5, And a A / F valve 609 for adjusting the supply amount of the city gas held at a constant gas pressure Ri. The downstream end of the city gas introduction pipe 601 opens to the mixer 56 (each branch portion of the air supply pipe 91) of the fuel gas introduction apparatus 5, and the mixer 56 causes the air supply pipe 91 to pass through the city gas introduction pipe 601. The city gas introduced into each branch portion and the fuel gas introduced into each branch portion of the air supply pipe 91 via the fuel gas introduction pipe 51 are mixed with the air in each branch portion of the air supply pipe 91. It is like that. Further, the opening adjustment mechanism 41 of the throttle valve 4 of each of the engines 9a to 9f, and the electromagnetic on-off valve 602, the gas pressure sensor 604, and the A / F valve 609 of the city gas introduction device 60 are connected to the controller 13. In accordance with a command from the controller 13, the optimum amount of city gas is controlled to be led from the city gas introduction pipe 601 to the combustion chamber 9 </ b> A of each engine 9 a to 9 f through the branch portion of the air supply pipe 91. . Further, the electromagnetic on-off valve 602 is of an open / close switching type, and only a small amount of city gas is introduced into the city gas introduction pipe 601 as long as the A / F valve 609 is not adjusted to open even if the electromagnetic on-off valve 602 is switched to the open state. It is configured as follows. In this case, when the engines 9a to 9f of the dual fuel engine 9 are driven by a mixed gas of city gas and fuel gas, the city gas flow rate control by the city gas introduction device 60 (A / F valve 609), the throttle valve 4 The fuel gas flow rate is controlled by the opening degree adjustment and the fuel gas introduction device 5 (A / F valve 59).

  The ignition coil 98 is ignited by a spark plug 97 and mixed with a mixture gas in which air is mixed with city gas and fuel gas by the mixer 56 of each engine 9a to 9f, and is connected to the controller 13.

  As a feature of the present invention, when starting the engines 9a to 9f of the dual fuel engine 9, the first first engine 9a is started only with city gas, and the driving load of the first engine 9a is started. After the fuel gas reaches a certain level, the first engine 9a is continuously driven by the mixed gas obtained by mixing the fuel gas with the city gas. Next, when the mixing ratio of the city gas in the mixed gas driving the first engine 9a reaches a predetermined value or less, the second second engine 9b is started only by the city gas, and this second After the driving load of the engine 9b becomes equal to or higher than a certain level, the second engine 9b is continuously driven by the mixed gas obtained by mixing the city gas with the fuel gas. Thereafter, when the mixing ratio of the city gas in the mixed gas driving the second engine 9b reaches a predetermined value or less, the subsequent third to sixth engines 9c to 9f are sequentially started according to the above procedure. So that it is controlled.

  Specifically, as shown in FIG. 17, the target value of the rotational speed of the first engine 9a is PID-controlled to determine the opening position of the throttle valve 4, and the flow rate is adjusted by the determined opening position. The city gas is supplied to the first engine 9a (combustion chamber 9A), and the driving of the first engine 9a using only the city gas is started. Then, when a predetermined time T3 (for example, tens of seconds) elapses after the driving load of the first engine 9a increases and becomes a constant value, the opening adjustment mechanism 41 of the throttle valve 4 and the electromagnetic opening / closing valve 52 of the fuel gas introduction device 5 The gas pressure sensor 54 and the A / F valve 59 are controlled by the controller 13 so that the fuel gas is guided from the fuel gas introduction pipe 51 to the combustion chamber 9A through the branch portion of the air supply pipe 91 of the first engine 9a. Then, fuel gas starts to be supplied to city gas. At this time, when the fuel gas starts to be supplied, the opening degree of the A / F valve 609 is also changed so as to reduce the supply amount of the city gas to a constant value, and the changed opening degree of the A / F valve 609 is set. On the basis of this, the opening degree of the A / F valve 59 is determined, and fuel gas whose supply amount is adjusted by the determined opening degree of the A / F valve 59 is supplied to the first engine 9a (combustion chamber 9A). Yes.

  Next, when the mixing ratio of the city gas in the mixed fuel driving the first engine 9a reaches a predetermined value or less, the throttle value determined by PID control of the target value of the rotational speed of the first engine 9a. The city gas whose flow rate is adjusted by the opening position of the valve 4 is supplied to the second engine 9b (combustion chamber 9A), and the driving of the second engine 9b using only the city gas is started. Then, when a predetermined time T3 (for example, several tens of seconds) elapses after the driving load of the second engine 9b increases and becomes a constant value, the opening adjustment mechanism 41 of the throttle valve 4 and the electromagnetic opening / closing valve 52 of the fuel gas introduction device 5 The gas pressure sensor 54 and the A / F valve 59 are controlled by the controller 13 so that the fuel gas is guided from the fuel gas introduction pipe 51 to the combustion chamber 9A through the branch portion of the air supply pipe 91 of the second engine 9b. Then, fuel gas starts to be supplied to city gas. At this time, when the fuel gas starts to be supplied, the opening degree of the A / F valve 609 is also changed so as to reduce the supply amount of the city gas to a constant value, and the changed opening degree of the A / F valve 609 is set. On the basis of this, the opening degree of the A / F valve 59 is determined, and the fuel gas whose supply amount is adjusted by the determined opening degree of the A / F valve 59 is supplied to the second engine 9b (combustion chamber 9A). Yes.

  Thereafter, when the mixing ratio of the city gas in the mixed fuel driving the second engine 9b reaches a predetermined value or less, the subsequent third to sixth engines 9c to 9f (combustion chamber 9A) are moved to the above-described position. Control to start sequentially according to the procedure.

  Further, when the supply amount of the fuel gas supplied from the fuel gas generation device X to the respective engines 9a to 9f of the dual fuel engine 9 decreases, the first engine 9a that stops at the beginning of the six engines 9a to 9f. When the supply of fuel gas to the first engine 9a is stopped and the supply amount of the city gas rising as the fuel gas supply stops in the first engine 9a exceeds a predetermined threshold value, the first engine 9a is stopped for a certain period of time. Stop after driving. Next, the fuel to the second second engine 9b that temporarily rises due to the supply of fuel gas to the first engine 9a being stopped, that is, the supply of fuel gas to the branch portion of the air supply pipe 91 of the first engine 9a is stopped. After the gas supply is stopped, the second engine 9b is driven for a certain period of time when the supply amount of the city gas that rises as the fuel gas supply stops in the second engine 9b exceeds a predetermined threshold value. Control to stop later. In the third to sixth engines 9c to 9f that are sequentially stopped thereafter, the supply of the fuel gas to the second engine 9b is stopped, that is, the fuel gas to the branch portion of the supply pipe 91 of the second engine 9b is stopped. After the supply of fuel gas to the third to sixth engines 9c to 9f, which rises temporarily due to the supply stop, is stopped according to the stop order of the remaining third to sixth engines 9c to 9f, the three engines When the supply amount of the city gas rising with the supply stop of the fuel gas in the third to sixth engines 9c to 9f after the first exceeds a predetermined threshold, the third to sixth engines after the third unit Control is performed so that the motors 9c to 9f are sequentially stopped after being driven for a certain time.

  Specifically, as shown in FIG. 18, when the supply amount of the fuel gas supplied from the fuel gas generation device X to each engine 9a to 9f of the dual fuel engine 9 decreases, the six engines 9a to 9a. The controller 13 controls the opening degree adjusting mechanism 41 of the throttle valve 4 of the first engine 9a that stops first in 9f, the electromagnetic on-off valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 to control the fuel. The supply of the fuel gas introduced from the gas introduction pipe 51 into the combustion chamber 9A of the first engine 9a through the branch portion of the air supply pipe 91 is stopped, that is, the supply of the fuel gas mixed with the city gas is stopped. At this time, the opening of the A / F valve 609 of the city gas introduction device 60 is changed in accordance with the stop of the fuel gas supply in the first engine 9a, the city gas supply amount increases, and the city gas supply amount is predetermined. When the opening of the A / F valve 609 is changed so as to decrease the supply amount of the city gas when the threshold value S1 is exceeded, the supply of the city gas when the driving load of the first engine 9a stops working The first engine 9a is stopped after changing the opening of the A / F valve 609 so as to keep the amount at a constant value (minimum value). In this case, the city gas supply amount is stopped when the opening degree of the A / F valve 609 is changed to decrease the city gas supply amount after the city gas supply amount exceeds the predetermined threshold value S1. The first engine 9a is driven only by city gas until a certain period of time elapses from the point in time.

  Next, the fuel gas supply to the second second engine 9b, which temporarily rises due to the stop of the supply of fuel gas to the first engine 9a, is the opening adjustment mechanism of the throttle valve 4 of the second engine 9b. 41. The controller 13 controls the electromagnetic open / close valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 to stop. At this time, the opening of the A / F valve 609 of the city gas introduction device 60 is changed in accordance with the stop of the fuel gas supply in the second engine 9b, the city gas supply amount increases, and the city gas supply amount is predetermined. When the opening of the A / F valve 609 is changed so as to decrease the supply amount of the city gas when the threshold value S2 is exceeded, the supply of the city gas is stopped when the driving load of the second engine 9b stops working. The second engine 9b is stopped after changing the opening of the A / F valve 609 so as to keep the amount at a constant value (minimum value). In this case, the city gas supply amount is stopped when the opening degree of the A / F valve 609 is changed so that the city gas supply amount decreases after the city gas supply amount exceeds the predetermined threshold value S2. The second engine 9b is driven only by city gas until a certain period of time elapses from the point in time.

  Thereafter, the supply of fuel gas to the third third engine 9c, which temporarily rises due to the stop of the supply of fuel gas to the second engine 9b, is used to adjust the opening of the throttle valve 4 of the third engine 9c. 41. The controller 13 controls the electromagnetic open / close valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 to stop. At this time, the opening of the A / F valve 609 of the city gas introduction device 60 is changed in accordance with the stop of the fuel gas supply in the third engine 9c, the city gas supply amount increases, and the city gas supply amount is predetermined. When the opening of the A / F valve 609 is changed so that the supply amount of the city gas is reduced when a threshold value (not shown) of the engine is exceeded, and the driving load of the third engine 9c stops working The third engine 9c is stopped after changing the opening of the A / F valve 609 so as to keep the supply amount of city gas at a constant value (minimum value).

  Then, the fuel gas supply to the fourth fourth engine 9d, which temporarily rises due to the supply stop of the fuel gas to the third engine 9c, is the opening adjustment mechanism of the throttle valve 4 of the fourth engine 9d. 41. The controller 13 controls the electromagnetic open / close valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 to stop. At this time, as shown in FIG. 19, the opening of the A / F valve 609 of the city gas introduction device 60 is changed with the stop of the supply of the fuel gas in the fourth engine 9d, and the supply amount of the city gas increases. When the supply amount of city gas exceeds a predetermined threshold value S4, the opening degree of the A / F valve 609 is changed so as to decrease the supply amount of city gas, and the driving load of the fourth engine 9d does not act. The fourth engine 9d is stopped after changing the opening of the A / F valve 609 so that the supply amount of the city gas is maintained at a constant value (minimum value).

  Thereafter, the supply of fuel gas to the fifth fifth engine 9e, which temporarily rises due to the stop of the supply of fuel gas to the fourth engine 9d, is adjusted to adjust the opening of the throttle valve 4 of the fifth engine 9e. The mechanism 41, the electromagnetic on-off valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 are controlled by the controller 13 and stopped. At this time, in the fifth engine 9e, the opening of the A / F valve 609 of the city gas introduction device 60 is changed with the stop of the supply of the fuel gas, and the supply amount of the city gas is increased. When the opening of the A / F valve 609 is changed so that the supply amount of the city gas is reduced when the threshold value S5 of the engine 5 is exceeded, the supply of the city gas is stopped when the driving load of the fifth engine 9e stops working. The fifth engine 9e is stopped after changing the opening of the A / F valve 609 so as to keep the amount constant (minimum value).

  Finally, the supply of the fuel gas to the sixth engine 9f, which temporarily rises due to the stop of the supply of the fuel gas to the fifth engine 9e, is the opening of the throttle valve 4 of the sixth engine 9f. The adjustment mechanism 41, the electromagnetic on-off valve 52, the gas pressure sensor 54, and the A / F valve 59 of the fuel gas introduction device 5 are controlled by the controller 13 and stopped. At this time, the opening of the A / F valve 609 of the city gas introduction device 60 is changed in accordance with the stop of the fuel gas supply in the sixth engine 9f, the city gas supply amount increases, and the city gas supply amount is predetermined. After a predetermined time has elapsed after changing the opening of the A / F valve 609 so that the supply amount of city gas is maintained at a constant value (maximum value in the ascending process) when the threshold value S6 is exceeded, The opening degree of the A / F valve 609 is changed so as to decrease the gas supply amount, and the city gas supply amount is held at a constant value (minimum value) when the driving load of the sixth engine 9f stops working. Thus, after changing the opening degree of the A / F valve 609, the sixth engine 9f is stopped.

  In this case, as shown in FIG. 20, the predetermined threshold values S1 to S6 (excluding S3) of the first to sixth engines 9a to 9f are gradually increased as the engine goes to the engine having a lower stop order. This is because the number of engines distributed to the combustion chambers 9A of the respective engines 9a to 9f gradually decreases through the branch portion of the supply pipe 91 due to the decrease of the fuel gas from the fuel gas generation device X, and the distribution This is because the supply amount of the city gas required to complete the combustion without leaving the fuel gas whose supply amount temporarily increases in the supply pipe 91 (branch portion) with a decrease in the number of engines to be increased increases.

  Therefore, in Embodiment 4 described above, each engine 9a to 9f is started only by the city gas when the six first to sixth engines 9a to 9f are started. Therefore, the mixed gas of the city gas and the fuel gas is used. Thus, the total calorific value of the mixed gas does not fluctuate greatly as in the case where the engine has been started, and an appropriate air-fuel ratio is obtained only with city gas. In addition, when the engines 9a to 9f are stopped, the amount of city gas that rises as the fuel gas is stopped from the fuel gas generator X to the engines 9a to 9f exceeds a predetermined threshold value S1 to S6. Since each engine 9a-9f is driven by light oil only for a certain period of time and then stopped, each engine is stopped with a mixed gas of city gas and fuel gas supplied. The mixed gas does not stop while remaining in each engine 9a to 9f, and the remaining of the mixed gas (fuel gas) in each engine 9a to 9f is eliminated by stopping after driving for a certain time with only city gas Thus, the air-fuel ratio does not fluctuate at the start. Thereby, the startability of each engine 9a-9f by an appropriate air fuel ratio can be improved. In addition, a large amount of water contained in the fuel gas does not stay in the engines 9a to 9f, and the engines 9a to 9f can be reliably started.

  In addition, when each engine 9a to 9f is started, after the first first engine 9a is started, the driving load of the engine 9a rises to become a constant value, and after a predetermined time T3 (for example, several tens of seconds) has passed, the city gas Since the fuel gas is mixed with the fuel gas and the mixing ratio of the city gas in the mixed gas reaches a certain value or less, the subsequent second to sixth engines 9b to 9f are sequentially started. The six first to sixth engines 9a to 9f are started one by one in accordance with the amount of fuel gas supplied from the fuel gas generator X, and each engine is started simultaneously when starting a plurality of engines. The consumption of city gas without inadvertently increasing the mixing ratio of city gas in the mixed gas when the amount of fuel gas supplied is small, and without causing misfire of the engines 9a to 9f. Reduce the amount of fuel gas It is possible to efficiently and actively use.

  Further, when the supply amount of the fuel gas supplied from the fuel gas generation device X has decreased, it is not necessary to drive all the six engines 9a to 9f by increasing the mixing ratio of the city gas in the mixed gas. Thus, only the number of engines corresponding to the degree of decrease in the amount of fuel gas supplied is driven, and the consumption of city gas can be reduced, and the six engines 9a to 9f can be driven efficiently.

  Further, the predetermined threshold values S1 to S6 of the respective engines 9a to 9f are gradually increased as the engine goes to the engine having the lower stop order, so that the fuel to the first engine 9a is stopped after the first first engine 9a is stopped. The fuel gas of the second to sixth engines 9b to 9f, whose supply amount temporarily increases due to the gas supply stoppage, is increased according to a predetermined threshold value that gradually increases as it goes to the engine with the lower stop order. The driving time by only the gas is ensured, and the remaining of the fuel gas that increases as the engine goes to a slow stop order is surely eliminated, so that the air-fuel ratio does not fluctuate when the engines 9a to 9f are started. The startability of the engines 9a to 9f can be improved more reliably. In addition, a large amount of water contained in the fuel gas does not stay in each engine 9a to 9f, and the startability of each engine 9a to 9f can be realized more reliably.

  In addition, this invention is not limited to said each Example, Other various modifications are included. For example, in the third and fourth embodiments, the dual fuel engines 8 and 9 that drive the six engines 8a to 8f and 9a to 9f have been described. However, the dual fuel engine that drives two or more engines is used. Of course it can be applied.

  In the first and third embodiments, the heat exchanger 103 that exchanges heat between the lubricating oil flowing through the lubricating oil passage 101 of the engine and the cooling water flowing through the cooling water passage 102 that cools the engine is provided as a dual fuel engine. Although provided at the bottom of the engines of 1 and 8, the lubricating oil flowing through the lubricating oil passage of the engine and the cooling water flowing through the cooling water passage for cooling the engine are also provided at the bottom of the dual fuel engine of the second and fourth embodiments. There may be provided a heat exchanger for exchanging heat with each other.

  In the second and fourth embodiments, the heat exchanger 72 that exchanges heat between the cooling water flowing through the cooling water passage 71 for cooling the engine and the fuel gas supplied to the engine from the supply pipe 61 is provided as a dual fuel engine. Although provided in the vicinity of the 6 and 9 engines, the coolant gas flowing in the cooling water passage for cooling the engine and the fuel gas supplied to the engine from the air supply pipe are also provided in the vicinity of the dual fuel engine of the first and third embodiments. There may be provided a heat exchanger for exchanging heat with each other.

  Further, in Embodiments 2 and 3, the dual fuel engines 6 and 9 are driven by a mixed gas of city gas and fuel gas generated from woody biomass. For example, mixing of propane gas and fuel gas is performed. The engine of the dual fuel engine may be driven by gas or the like, and the type of fuel to be combined is not particularly limited.

It is a control system block diagram of the dual fuel engine which concerns on Example 1 of this invention. It is a time chart figure which shows the control procedure by the controller at the time of similarly starting a single engine. It is a time chart figure which shows the control procedure by the controller at the time of stopping a single engine similarly. It is a control system block diagram of the dual fuel engine which concerns on Example 2 of this invention. It is a time chart figure which shows the control procedure by the controller at the time of similarly starting a single engine. It is a time chart figure which shows the control procedure by the controller at the time of stopping a single engine similarly. It is a characteristic view which similarly shows the characteristic of the target value of the opening degree of the throttle valve with respect to the driving load of the engine. It is explanatory drawing of the engine vicinity which shows the structure which heat-exchanges the mixed gas in a supply pipe similarly with cooling water. It is a figure which shows the layout of the some engine and fuel gas generation apparatus of the dual fuel engine which concern on Example 3 of this invention. It is the control system block diagram of the engine of a dual fuel engine similarly. It is a time chart figure which similarly shows the control procedure by the controller at the time of starting a 1st and 2nd engine. It is a time chart figure which similarly shows the control procedure by the controller at the time of stopping a 1st and 2nd engine. It is a time chart figure which similarly shows the control procedure by the controller at the time of stopping a 5th and 6th engine. It is a characteristic view which shows the characteristic of the supply amount of the light oil with respect to each engine at the time of a stop similarly. It is a figure which shows the layout of the some engine and fuel gas production | generation apparatus of the dual fuel engine which concern on Example 4 of this invention. It is the control system block diagram of the engine of a dual fuel engine similarly. It is a time chart figure which similarly shows the control procedure by the controller at the time of starting a 1st and 2nd engine. It is a time chart figure which similarly shows the control procedure by the controller at the time of stopping a 1st and 2nd engine. It is a time chart figure which similarly shows the control procedure by the controller at the time of stopping a 5th and 6th engine. It is a characteristic view which shows the characteristic of the supply amount of the light oil with respect to each engine at the time of a stop similarly.

Explanation of symbols

1, 6, 8, 9 Dual fuel engine 11, 61, 81, 91 Air supply pipe (air supply path)
4 Throttle valve (throttle)
8a-8f, 9a-9f Engine X Fuel gas generator (low-calorie gas supply source)

Claims (8)

The engine is driven by a high-calorie fuel that generates a sufficient calorific value by itself, and a mixed fuel that is a mixture of low-calorie fuel that has an insufficient calorific value and fluctuates in itself. In the dual fuel engine control method,
When starting the engine, start the engine only with high-calorie fuel,
Thereafter, the control method for the dual fuel engine is controlled such that the low calorie fuel is mixed with the high calorie fuel after the driving load of the engine becomes equal to or higher than a certain level. The engine is driven by a high-calorie fuel that generates a sufficient calorific value by itself, and a mixed fuel that is a mixture of low-calorie fuel that has an insufficient calorific value and fluctuates in itself. In the dual fuel engine control method,
When stopping the engine, stop the supply of low calorie fuel mixed with high calorie fuel before stopping the engine,
A control method for a dual fuel engine, wherein the engine is controlled to stop after being driven for a certain period of time only with high-calorie fuel. A high-calorie fuel that generates a sufficient calorific value by itself, and a mixed fuel in which a low-calorie fuel whose calorific value is insufficient and the calorific value itself fluctuates alone is mixed with this high-calorie fuel. In the control method of the dual fuel engine that drives the engine,
When starting multiple engines, start the first engine with high-calorie fuel only, and after the driving load of the first engine has exceeded a certain level, the low-calorie fuel is compared to the high-calorie fuel. The first engine is continuously driven by the mixed fuel mixed with
Next, when the mixing ratio of the high calorie fuel in the mixed fuel driving the first engine reaches a certain value or less, the second engine is started only with the high calorie fuel, and the two units After the driving load of the second engine exceeds a certain level, the second engine is continuously driven by the mixed fuel obtained by mixing the low calorie fuel with the high calorie fuel,
After that, when the mixing ratio of the high calorie fuel in the mixed fuel driving the second engine reaches a certain value or less, the subsequent engines are controlled to be sequentially started according to the above procedure. A control method of a dual fuel engine characterized by the above. A high-calorie fuel that generates a sufficient calorific value by itself, and a mixed fuel in which a low-calorie fuel in which the calorific value is insufficient and the calorific value itself varies with this high-calorie fuel is mixed, In the control method of the dual fuel engine that drives the engine,
When the supply amount of the low calorie fuel supplied from the low calorie fuel supply source to a plurality of engines decreases, the supply of the low calorie fuel to the first engine among the plurality of engines is stopped. When the supply amount of high-calorie fuel that rises due to the stop of supply of low-calorie fuel in the second engine exceeds a predetermined threshold value, the engine is driven for a certain period of time and then stopped.
Next, after stopping the supply of low calorie fuel to the second and subsequent engines that temporarily rises due to the supply stop of low calorie fuel to the first engine, the second engine is stopped according to the stop order of the remaining engines. In subsequent engines, when the supply amount of high-calorie fuel that rises due to the stop of supply of low-calorie fuel exceeds a predetermined threshold, the second and subsequent engines are driven for a certain period of time and then stopped sequentially. A control method of a dual fuel engine, characterized by being controlled. In the control method of the dual fuel engine according to claim 4,
The control method for a dual fuel engine, wherein the predetermined threshold value of each engine gradually increases as the engine goes to a slow stop order. In the control method of the dual fuel engine according to any one of claims 1 to 4,
While setting the target value of the throttle opening of the air supply path for the engine driving load,
Using a high-calorie gas that generates a sufficient calorific value by itself, and a mixed gas in which a low-calorie gas in which the calorific value is insufficient and the calorific value itself varies with this high-calorie gas is mixed,
When the engine drive load partially fluctuates, the amount of low calorie gas supplied is controlled so that the throttle opening of the air supply path that is correlated with the calorific value of the low calorie gas becomes the target value. A control method of a dual fuel engine characterized by the above. In the control method of the dual fuel engine according to any one of claims 1 to 4,
A control method of a dual fuel engine, characterized in that low-calorie fuel is supplied to the engine in a state heated by heat exchange with engine cooling water in the vicinity of the engine. In the control method of the dual fuel engine according to any one of claims 1 to 4,
A control method for a dual fuel engine, characterized in that the engine lubricating oil is kept at a certain temperature or higher by heat exchange with engine cooling water.

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