JP2011127544A - Gas engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas engine control device capable of controlling a combustion time of an air-fuel mixture in a specific time, regardless of a change with time. <P>SOLUTION: This gas engine control device includes an engine speed control part 111b for controlling the opening of a throttle valve 23 based on the deviation between an engine speed Ne and an engine speed command value NeO, an air-fuel mixture flow rate control part 111c for determining an air-fuel mixture flow rate command value QmixO from a load Ld and the engine speed command value NeO, calculating a viscosity corrected actual air-fuel mixture flow rate QmixR based on the air-fuel mixture temperature Tmix, air-fuel mixture pressure Pmix and the engine speed Ne and controlling the opening of a fuel gas control valve 42 based on the deviation between the air-fuel mixture flow rate command value QmixO and the viscosity corrected actual air-fuel mixture flow rate QmixR, and a discharge timing control part 111d for determining an exhaust temperature command value TgO from the air-fuel mixture flow rate command value QmixO and controlling timing when an ignition plug 16 discharges based on the deviation between an exhaust temperature command value TgO and the exhaust temperature Tg. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a gas engine control device.

  Conventionally, a gas engine that uses a fuel gas such as natural gas or city gas to perform combustion operation maintains an optimal combustion state in which knocking or misfire does not occur, and in order to suppress NOx and the like contained in exhaust gas, Gas that is adjusted to a ratio between the flow rate of the outside air (air) and the flow rate of the fuel gas (outside air flow rate / fuel gas flow rate) (hereinafter simply referred to as “air-fuel ratio”) according to the characteristics of the fuel gas used Engine control devices are known.

  In such a gas engine control device, for example, as disclosed in Patent Document 1, the flow rate of fuel gas determined from the target rotation speed and output of the gas engine (hereinafter simply referred to as “fuel gas flow rate command value”). Calculate the flow rate (hereinafter simply referred to as “mixture flow rate command value”) of the supply air (hereinafter simply referred to as “mixture”) mixed with outside air at the optimum air-fuel ratio, and calculate it from the mixture temperature and mixture pressure. Some have an air-fuel ratio control process for setting a target opening of the throttle valve based on a deviation between the calculated flow rate of the air-fuel mixture (hereinafter simply referred to as “actual air-fuel flow rate”) and the air-fuel flow rate command value. . In this way, NOx and the like contained in the exhaust gas are suppressed by controlling the air-fuel mixture to an appropriate air-fuel ratio by the gas engine control device.

  However, in general, in a gas engine, the plug gap of the spark plug expands with time, and the volume of the cylinder decreases due to soot accumulated in the cylinder. This improves the ignitability of the air-fuel mixture by the spark plug and increases the temperature in the combustion chamber during the compression stroke of the piston, so that the air-fuel mixture burns rapidly and the combustion time is shortened. Therefore, the air-fuel mixture burns rapidly while the piston is in the position near the top dead center (high compression ratio state), so the pressure and temperature of the combustion chamber at the time of combustion are the combustion at the time of combustion before the change with time. It becomes higher and higher than the pressure and temperature of the chamber. As a result, the reaction between oxygen and nitrogen in the air-fuel mixture is promoted, and the amount of NOx emission increases.

  In this case, the amount of NOx emission can be reduced by controlling the air-fuel ratio of the air-fuel mixture to the lean side and suppressing the increase in the pressure and temperature of the combustion chamber during combustion. On the other hand, since the air-fuel mixture completes combustion in a short time, the exhaust temperature is lower than the exhaust temperature before the change with time. Further, the exhaust gas temperature is further lowered by controlling the air-fuel ratio of the air-fuel mixture to the lean side to lower the temperature during combustion. Therefore, the temperature of the catalyst heated by the heat of the exhaust also decreases, which is disadvantageous in that the ability of the catalyst to reduce NOx and the like decreases.

JP 2009-57872 A

  The present invention has been made in view of such problems, and the combustion time of the air-fuel mixture is kept constant even when the ignitability of the air-fuel mixture is improved due to changes over time or the temperature of the combustion chamber in the compression stroke rises. It is an object of the present invention to provide a gas engine control device that can be controlled at a predetermined time.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, the invention of claim 1 is a mixture temperature detecting means for detecting the mixture temperature, a mixture pressure detecting means for detecting the mixture pressure, an engine speed detecting means for detecting the engine speed, and an exhaust temperature. The engine speed command value is determined from the exhaust temperature detecting means for detecting the engine load and the load applied to the load device driven by the engine, and the deviation between the detected engine speed and the determined engine speed command value is determined. Based on the engine speed control means for controlling the opening degree of the throttle valve based on the load, the load supplied to the load device, and the determined engine speed command value, the mixture flow rate command value is determined, and the detected mixture The actual mixture flow rate is calculated based on the temperature, the detected mixture pressure, and the detected engine speed, and based on the deviation between the determined mixture flow rate command value and the calculated actual mixture flow rate. Mixture flow rate control means for controlling the opening degree of the fuel gas control valve, and an exhaust temperature command value is determined from the determined mixture flow rate command value, and the deviation between the determined exhaust temperature command value and the detected exhaust temperature Discharge timing control means for controlling the timing at which the spark plug discharges based on the above.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, the flow rate of the air-fuel mixture is controlled by controlling the opening degree of the fuel gas control valve, and the discharge timing of the spark plug is controlled so that the exhaust gas temperature becomes a predetermined temperature. The combustion time can be controlled to a fixed time. As a result, even if the ignitability of the air-fuel mixture improves due to changes over time or the temperature of the combustion chamber rises during the compression stroke, the increase in the pressure and temperature of the combustion chamber during combustion of the air-fuel mixture is suppressed. The Thereby, the NOx concentration discharged from the gas engine can be maintained at the target NOx concentration.

The figure which shows the structure of the gas engine which concerns on one Embodiment of this invention. The flowchart figure which shows the control process of the gas engine control apparatus which concerns on one Embodiment of this invention. The flowchart figure which shows the engine speed control process of the gas engine control apparatus which concerns on one Embodiment of this invention. The flowchart figure which shows the air-fuel | gaseous mixture flow rate control process of the gas engine control apparatus which concerns on one Embodiment of this invention. The flowchart figure which shows the discharge timing control process of the gas engine control apparatus which concerns on one Embodiment of this invention. (A) The figure which shows the graph showing the change of the exhaust temperature by the time-dependent change of the gas engine which concerns on one Embodiment of this invention. (B) The figure which shows the graph showing the change of the combustion time by the discharge timing control process of the gas engine control apparatus which concerns on one Embodiment of this invention. (A) The figure which shows the graph showing the control aspect which maintains exhaust gas temperature in the discharge timing control process by the gas engine control apparatus which concerns on one Embodiment of this invention. (B) The figure which shows the graph showing the control aspect which maintains a NOx density | concentration in the discharge timing control process by the gas engine control apparatus which concerns on one Embodiment of this invention. The figure which shows the graph showing the change of NOx density | concentration by the discharge timing control process of the gas engine control apparatus which concerns on one Embodiment of this invention.

  Hereinafter, a gas engine control apparatus 100 according to an embodiment of the gas engine control apparatus of the present invention and a gas engine 1 that is an internal combustion engine to which the gas engine control apparatus 100 is applied will be described with reference to FIG. In this embodiment, “upstream side” indicates the upstream side in the flow direction of the air-fuel mixture, and “downstream side” indicates the downstream side in the flow direction of the air-fuel mixture. Further, the upper and lower directions are defined with the direction in which the piston 13 compresses the air-fuel mixture as the upward direction.

  As shown in FIG. 1, the gas engine 1 is a single-cylinder engine or a multi-cylinder engine, and performs a combustion operation using a fuel gas such as natural gas. The gas engine 1 mainly includes an engine body 10, an air supply path 20, an exhaust path 30, and a fuel gas supply path 40. The gas engine 1 is configured such that an output shaft (not shown) is connected to a generator 50 that is an external application, and the generator 50 is operated. In addition, the external application which the gas engine 1 operates is not limited to the generator 50 in this embodiment.

  The engine main body 10 has a cylinder head 12 fixed to an upper portion of a cylinder block 11 which is a main constituent member. In the engine main body 10, a piston 13 is slidably housed in a cylinder 10a formed in a cylinder block 11, and a combustion chamber 14 is formed above the piston 13 in the cylinder 10a. The cylinder head 12 includes an air supply valve 15 that communicates or blocks the air supply path 20 and the combustion chamber 14, an ignition plug 16 that ignites the air-fuel mixture supplied to the combustion chamber 14, and an exhaust path 30 and the combustion chamber 14. Is provided with an exhaust valve 17 for communicating or shutting off. A crankshaft 19 connected to the engine body 10 via a piston 13 and a connecting rod 18 is rotatably supported. The engine body 10 is configured to convert the reciprocating motion of the piston 13 into a rotational motion by the crankshaft 19 and to output to the generator 50 via an output shaft (not shown).

  The air supply path 20 supplies an air-fuel mixture of outside air and fuel gas to the engine body 10. The air supply path 20 includes an air supply pipe 21, a venturi 22, a throttle valve 23, and the like.

  The air supply pipe 21 is a main structural member of the air supply path 20. One of the air supply pipes 21 communicates with the combustion chamber 14 of the engine body 10 via the air supply valve 15 and the other is released to the atmosphere. Therefore, the supply pipe 21 is configured to be able to supply outside air into the combustion chamber 14. A fuel gas supply path 40 is connected to the supply pipe 21 in the middle thereof.

  The venturi 22 generates a differential pressure between the fuel gas in the fuel gas supply path 40 and the air (outside air) in the air supply pipe 21. The venturi 22 is provided at a connection portion of the fuel gas supply path 40 in the air supply pipe 21. The venturi 22 is configured to be able to supply the fuel gas in the fuel gas supply path 40 into the air supply pipe 21 by the differential pressure generated in the air supply pipe 21.

  The throttle valve 23 changes the flow rate of the air-fuel mixture. The throttle valve 23 is provided on the downstream side of the venturi 22 in the air supply pipe 21. The throttle valve 23 is an automatic valve that can be opened and closed by an actuator such as an electric motor. The throttle valve 23 can change the flow rate of the air-fuel mixture supplied to the engine body 10 by adjusting the opening thereof.

  The exhaust path 30 is for exhausting the exhaust discharged from the engine body 10 to the outside after performing a NOx reduction process or the like. The exhaust path 30 includes an exhaust pipe 31, a filter (not shown), an oxidation catalyst, and the like.

  The exhaust pipe 31 is a main structural member of the exhaust path 30. One of the exhaust pipes 31 communicates with the combustion chamber 14 of the engine body 10 via the exhaust valve 17, and the other is released to the atmosphere via a filter, an oxidation catalyst, etc. (not shown). Therefore, the exhaust pipe 31 is configured to be able to exhaust the exhaust gas in the combustion chamber 14 to the outside.

  The fuel gas supply path 40 supplies fuel gas to the air supply path 20. The fuel gas supply path 40 includes a fuel gas supply pipe 41, a fuel gas control valve 42, and the like.

  The fuel gas supply pipe 41 is a main structural member of the air supply path 20. One of the fuel gas supply pipes 41 is connected to the air supply pipe 21 of the air supply path 20, and the other is connected to a fuel gas tank (not shown) that stores fuel gas. Therefore, the fuel gas supply pipe 41 is configured to be able to supply fuel gas in a fuel gas tank (not shown) into the air supply pipe 21.

  The fuel gas control valve 42 supplies or stops supplying fuel gas, and changes the flow rate of the fuel gas. The fuel gas control valve 42 is provided in the middle of the fuel gas supply pipe 41. The fuel gas control valve 42 is an automatic valve that can be opened and closed by an actuator such as an electric motor. The fuel gas control valve 42 can change the flow rate of the supplied fuel gas by supplying or stopping the supply of the fuel gas to the air supply path 20 by opening and closing the valve and adjusting the opening of the valve.

  As shown in FIG. 1, the gas engine control device 100 controls the operation of the gas engine 1. The gas engine control apparatus 100 includes an ECU 110, an engine speed detection sensor 120 as engine speed detection means, a mixture temperature detection sensor 130 as mixture temperature detection means, and a mixture pressure detection sensor as mixture pressure detection means. 140, and an exhaust temperature detection sensor 150 which is an exhaust temperature detection means.

The ECU 110 performs various programs for controlling the gas engine 1 and the relationship between the air-fuel ratio map M1, the exhaust gas temperature map M2, the exhaust gas temperature Tg, and the discharge angle Deg, which is the angle of the crankshaft 19 that the spark plug 16 discharges. Data such as the discharge angle map M3, the charging efficiency η _c , and the stroke volume V _s of the gas engine 1 are stored, and these programs can be developed, and predetermined calculations can be performed according to these programs and the like. The result of the calculation can be stored.

  The ECU 110 may actually have a configuration in which a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or may be configured by a one-chip LSI or the like. In the present embodiment, it can be achieved by using a dedicated product or by storing the above-described program in a commercially available personal computer or workstation. The ECU 110 mainly includes a control unit 111, an input unit 112, an output unit 113, and the like.

  The control unit 111 functionally includes a storage unit 111a, an engine speed control unit 111b which is an engine speed control unit, an air-fuel mixture flow control unit 111c which is an air-fuel flow rate control unit, and a discharge timing which is a discharge timing control unit. A control unit 111d is provided. Substantially, the control unit 111 performs a predetermined calculation or the like according to a program stored in the storage unit 111a, so that the storage unit 111a, the engine speed control unit 111b, the mixture flow rate control unit 111c, and the discharge timing. It functions as the control unit 111d.

Of the control unit 111, the storage unit 111a and the engine speed control unit 111b cooperate to perform each process constituting one embodiment of the gas engine control device 100 according to the present invention. Of the control unit 111, the storage unit 111a and the air-fuel mixture flow rate control unit 111c cooperate to perform each process constituting one embodiment of the gas engine control device 100 according to the present invention. Of the control unit 111, the storage unit 111a and the discharge timing control unit 111d cooperate to perform each process constituting one embodiment of the gas engine control device 100 according to the present invention.
Specific functions of the storage unit 111a, the engine speed control unit 111b, the mixture flow rate control unit 111c, and the discharge timing control unit 111d will be described later.

  The input unit 112 is connected to the control unit 111, and signals from the engine speed detection sensor 120, the mixture temperature detection sensor 130, the mixture pressure detection sensor 140, and the generator 50 that is a command value setting unit are connected to the control unit 111. And command values are input.

  The output unit 113 is connected to the control unit 111, and outputs signals from the control unit 111 to the fuel gas control valve 42, the throttle valve 23, and the spark plug 16.

  The engine speed detection sensor 120 detects the engine speed Ne. The engine speed detection sensor 120 includes a rotary encoder or the like, and is provided on the crankshaft 19 of the gas engine 1. Further, the engine speed detection sensor 120 is configured to be able to detect the angle of the crankshaft 19, that is, the crank angle at the same time. In this embodiment, the engine speed detection sensor 120 is a rotary encoder. However, the engine speed detection sensor 120 is not particularly limited as long as it can detect the engine speed Ne and the crank angle.

  The mixture temperature detection sensor 130 detects the mixture temperature Tmix. The air-fuel mixture temperature detection sensor 130 is arranged in the middle of the air supply pipe 21 and downstream of the throttle valve 23. The position where the mixture temperature detection sensors 130 are arranged and the number of the mixture temperature detection sensors 130 are not particularly limited in the present embodiment, and any configuration can be used as long as the mixture temperature Tmix can be detected as appropriate. Good.

  The mixture pressure detection sensor 140 detects the mixture pressure Pmix. The mixture pressure detection sensor 140 is disposed in the middle of the supply pipe 21 and in the vicinity of the mixture temperature detection sensor 130. Note that the positions at which the mixture pressure detection sensors 140 are arranged and the number of the mixture pressure detection sensors 140 are not particularly limited in the present embodiment, and any configuration that can appropriately detect the mixture pressure Pmix is possible. Good.

  The exhaust temperature detection sensor 150 detects the exhaust temperature Tg. The exhaust temperature detection sensor 150 is disposed in the middle of the exhaust pipe 31. Note that the positions at which the exhaust temperature detection sensors 150 are arranged and the number of the exhaust temperature detection sensors 150 are not particularly limited in the present embodiment, and any configuration that can appropriately detect the exhaust temperature Tg may be used.

  As shown in FIG. 1, the input unit 112 of the ECU 110 is connected to the engine speed detection sensor 120 and can acquire the engine speed Ne and the crank angle detected by the engine speed detection sensor 120.

  The input unit 112 of the ECU 110 is connected to the mixture temperature detection sensor 130, and can acquire the mixture temperature Tmix detected by the mixture temperature detection sensor 130.

  The input unit 112 of the ECU 110 is connected to the mixture pressure detection sensor 140 and can acquire the mixture pressure Pmix detected by the mixture pressure detection sensor 140.

  The input unit 112 of the ECU 110 is connected to the exhaust temperature detection sensor 150 and can acquire the exhaust temperature Tg detected by the exhaust temperature detection sensor 150.

  The input unit 112 of the ECU 110 is connected to a generator 50 that is a load device, and can acquire a load Ld that is input to the generator 50.

  The output unit 113 of the ECU 110 is connected to the spark plug 16 via an ignition device (not shown), and can transmit a discharge signal of the spark plug 16.

  The output unit 113 of the ECU 110 is connected to the throttle valve 23 and can transmit a setting signal for the opening degree of the throttle valve 23.

  The output unit 113 of the ECU 110 is connected to the fuel gas control valve 42 and can transmit a setting signal for the opening degree of the fuel gas control valve 42.

  Below, the control aspect of the gas engine control apparatus 100 which concerns on this invention is demonstrated using FIG.2, FIG.3, FIG.4 and FIG.

  As shown in FIG. 2, the control mode of the gas engine control device 100 according to the present invention includes an engine speed control process A, a mixture flow rate control process B, and an ignition timing control process C.

  In the engine speed control process A, the engine speed command value NeO is determined from the load Ld by the cooperation of the storage section 111a and the engine speed control section 111b in the control section 111, and the engine speed Ne and This is a stroke for controlling the opening degree of the throttle valve 23 based on the deviation from the engine speed command value NeO.

In the mixture flow rate control step B, the mixture portion flow rate command value QmixO is calculated from the load Ld and the engine speed command value NeO by the cooperation of the storage unit 111a and the mixture flow rate control unit 111c in the control unit 111. decide. Next, based on the gas mixture temperature Tmix and the gas mixture viscosity μ ₀ at 0 ° C., the gas mixture viscosity μ _Tmix shown in the following _{equation 1} is calculated. Further, based on the calculated air-fuel mixture viscosity μ _Tmix , air-fuel mixture temperature Tmix, air-fuel mixture pressure Pmix, engine speed Ne, charging efficiency η _c , and stroke volume V _s , the viscosity-corrected actual air-fuel mixture flow shown in the following equation 2 QmixR is calculated. Then, the opening degree of the fuel gas control valve 42 is controlled based on the deviation between the mixture flow rate command value QmixO and the viscosity corrected actual mixture flow rate QmixR.

In the ignition timing control step C, the spark plug 16 is discharged based on the deviation between the exhaust temperature command value TgO and the exhaust temperature Tg by the cooperation of the storage unit 111a and the discharge timing control unit 111d in the control unit 111. This is a process of correcting the timing to perform.

  Below, the control aspect of the throttle valve 23, the fuel gas control valve 42, and the spark plug 16 by ECU110 is demonstrated.

In step S100, the ECU 110 starts an engine speed control process A and shifts the control stage to step S110 (see FIG. 3).
As shown in FIG. 3, in step S <b> 110, the ECU 110 acquires the load Ld input to the generator 50 that is the load device and the engine speed Ne detected by the engine speed detection sensor 120 through the input unit 112. . ECU110 memorize | stores the load Ld and the engine speed Ne which the input part 112 acquired in the memory | storage part 111a of the control part 111, and transfers a control step to step S120.

  In step S120, the ECU 110 determines the engine speed command value NeO by the engine speed control unit 111b of the control unit 111 based on the load Ld and the air-fuel ratio map M1 stored in the storage unit 111a of the control unit 111. To do. The ECU 110 stores the engine speed command value NeO determined by the engine speed control unit 111b of the control unit 111 in the storage unit 111a of the control unit 111, and then shifts the control stage to step S130.

In step S130, the ECU 110 determines whether the engine speed Ne stored in the storage unit 111a of the control unit 111 is equal to the engine speed command value NeO by the engine speed control unit 111b of the control unit 111.
As a result, when it is determined that the engine speed Ne is equal to the engine speed command value NeO, the ECU 110 ends the engine speed control process A and shifts the control stage to step S200 (see FIG. 2).
If it is determined that the engine rotational speed Ne is not equal to the engine rotational speed command value NeO, the ECU 110 proceeds to a control step to step S140.

In step S140, the ECU 110 determines whether the engine speed Ne stored in the storage unit 111a of the control unit 111 is larger than the engine speed command value NeO by the engine speed control unit 111b of the control unit 111.
As a result, when it is determined that the engine speed Ne is larger than the engine speed command value NeO, the ECU 110 proceeds to a control step to step S150.
If it is determined that the engine rotational speed Ne is smaller than the engine rotational speed command value NeO, the ECU 110 proceeds to a control step to step S160.

  In step S150, the ECU 110 controls the throttle valve based on the difference between the engine speed Ne stored in the storage unit 111a of the control unit 111 and the engine speed command value NeO by the engine speed control unit 111b of the control unit 111. An opening correction amount SvH of 23 is calculated. The ECU 110 controls the engine speed control unit 111b of the control unit 111 so that the opening degree of the throttle valve 23 is decreased by the opening correction amount SvH via the output unit 113, and then ends the engine speed control process A. Then, the control stage proceeds to step S200 (see FIG. 2).

  In step S160, the ECU 110 controls the throttle valve based on the deviation between the engine speed Ne stored in the storage unit 111a of the control unit 111 and the engine speed command value NeO by the engine speed control unit 111b of the control unit 111. An opening correction amount SvH of 23 is calculated. The ECU 110 controls the engine speed control unit 111b of the control unit 111 to increase the opening of the throttle valve 23 by the opening correction amount SvH via the output unit 113, and then ends the engine speed control process A. Then, the control stage proceeds to step S200 (see FIG. 2).

  As shown in FIG. 2, in step S200, the ECU 110 starts an air-fuel mixture flow rate control step B, and the control stage proceeds to step S210 (see FIG. 4).

  As shown in FIG. 4, in step S210, the ECU 110 causes the mixture flow rate control unit 111c of the control unit 111 to store the load Ld, the engine speed command value NeO, and the air-fuel ratio that are stored in the storage unit 111a of the control unit 111. A mixture flow rate command value QmixO is determined based on the map M1. The ECU 110 stores the mixture flow rate command value QmixO determined by the mixture flow rate control unit 111c of the control unit 111 in the storage unit 111a of the control unit 111, and then shifts the control stage to step S220.

  In step S220, the ECU 110 detects, by the input unit 112, the engine speed Ne detected by the engine speed detection sensor 120, the mixture temperature Tmix detected by the mixture temperature detection sensor 130, and the mixture pressure detection sensor 140. The mixture pressure Pmix is acquired. The ECU 110 stores the engine speed Ne, the mixture temperature Tmix, and the mixture pressure Pmix acquired by the input unit 112 in the storage unit 111a of the control unit 111, and then shifts the control step to step S230.

In step S230, the ECU 110 causes the mixture flow rate control unit 111c of the control unit 111 to store the engine speed Ne, the mixture temperature Tmix, and the mixture viscosity μ _{0 at} 0 ° C. stored in the storage unit 111a of the control unit 111. Based on the above, the air-fuel mixture viscosity μ _Tmix shown in the above _{equation 1} is calculated. The ECU 110 stores the mixture viscosity μ _Tmix calculated by the mixture flow rate control unit 111c of the control unit 111 in the storage unit 111a of the control unit 111, and then shifts the control step to step S240.

In step S240, the ECU 110 causes the mixture flow rate control unit 111c of the control unit 111 to store the mixture viscosity μ _Tmix , the engine speed Ne, the mixture temperature Tmix, and the mixture pressure stored in the storage unit 111a of the control unit 111. Based on Pmix, the charging efficiency η _c , and the stroke volume V _s , the viscosity-corrected actual mixture flow rate QmixR shown in Equation 2 is calculated. The ECU 110 stores the viscosity corrected actual mixture flow rate QmixR calculated by the mixture flow rate control unit 111c of the control unit 111 in the storage unit 111a of the control unit 111, and then shifts the control step to step S250.

In step S250, the ECU 110 determines whether the viscosity correction actual mixture flow rate QmixR stored in the storage unit 111a of the control unit 111 is equal to the mixture flow rate command value QmixO by the mixture flow rate control unit 111c of the control unit 111. judge.
As a result, when it is determined that the viscosity corrected actual mixture flow rate QmixR is equal to the mixture flow rate command value QmixO, the ECU 110 ends the mixture flow rate control step B and shifts the control stage to step S300 (see FIG. 2). .
If it is determined that the viscosity-corrected actual mixture flow rate QmixR is not equal to the mixture flow rate command value QmixO, the ECU 110 shifts the control step to step S260.

In step S260, the ECU 110 determines whether or not the viscosity corrected actual mixture flow rate QmixR stored in the storage unit 111a of the control unit 111 is larger than the mixture flow rate command value QmixO by the mixture flow rate control unit 111c of the control unit 111. judge.
As a result, when it is determined that the viscosity corrected actual mixture flow rate QmixR is larger than the mixture flow rate command value QmixO, that is, the ratio (air-fuel ratio) between the flow rate of the fuel gas constituting the mixture and the flow rate of the outside air (air) is When it is too small (lean side) with respect to the appropriate value and the air-fuel mixture flow rate is increasing in order to maintain the necessary fuel gas flow rate, the ECU 110 shifts the control stage to step S270.
Further, when it is determined that the viscosity-corrected actual mixture flow rate QmixR is smaller than the mixture flow rate command value QmixO, that is, the ratio (air-fuel ratio) between the flow rate of the fuel gas constituting the mixture and the flow rate of the outside air (air) is appropriate. If the value is excessive (rich side) with respect to the value and the air-fuel mixture flow rate is decreasing in order to maintain the required fuel gas flow rate, the ECU 110 shifts the control step to step S280.

  In step S270, the ECU 110 controls the mixture flow rate control unit 111c of the control unit 111 based on the deviation between the viscosity corrected actual mixture flow rate QmixR and the mixture flow rate command value QmixO stored in the storage unit 111a of the control unit 111. Then, the opening correction amount FvH of the fuel gas control valve 42 is calculated. The ECU 110 controls the air-fuel mixture flow rate control step B after the air-fuel flow rate control unit 111c of the control unit 111 controls the opening degree of the fuel gas control valve 42 to be increased by the opening correction amount FvH via the output unit 113. And the control stage proceeds to step S300 (see FIG. 2).

  In step S280, the ECU 110 controls the mixture flow rate control unit 111c of the control unit 111 based on the deviation between the viscosity corrected actual mixture flow rate QmixR and the mixture flow rate command value QmixO stored in the storage unit 111a of the control unit 111. Then, the opening correction amount FvH of the fuel gas control valve 42 is calculated. The ECU 110 controls the air-fuel mixture flow rate control step B after the air-fuel mixture flow rate control unit 111c of the control unit 111 controls the output of the fuel gas control valve 42 to be decreased by the opening correction amount FvH via the output unit 113. And the control stage proceeds to step S300 (see FIG. 2).

  As shown in FIG. 2, in step S300, the ECU 110 starts an ignition timing control process C, and the control stage proceeds to step S310 (see FIG. 5).

  As shown in FIG. 5, in step S310, the ECU 110 causes the discharge timing control unit 111d of the control unit 111 to set the mixture flow rate command value QmixO and the exhaust temperature map M2 stored in the storage unit 111a of the control unit 111. Based on this, an exhaust temperature command value TgO (exhaust temperature target value) is determined. The ECU 110 stores the exhaust gas temperature command value TgO determined by the discharge timing control unit 111d of the control unit 111 in the storage unit 111a of the control unit 111, and then shifts the control stage to step S320.

  In step S320, ECU 110 obtains a crank angle detected by engine speed detection sensor 120 through input unit 112. When the crank angle matches the discharge angle Deg stored in the storage unit 111a of the control unit 111 by the discharge timing control unit 111d of the control unit 111, the ECU 110 turns on the output unit 113 and an ignition device (not shown). Then, after the spark plug 16 is discharged, the control stage proceeds to step S330.

  In step S330, the ECU 110 acquires the exhaust gas temperature Tg detected by the exhaust gas temperature detection sensor 150 through the input unit 112. ECU110 memorize | stores the exhaust temperature Tg which the input part 112 acquired in the memory | storage part 111a of the control part 111, and transfers a control step to step S340.

In step S340, the ECU 110 determines whether or not the exhaust temperature Tg stored in the storage unit 111a of the control unit 111 is equal to the exhaust temperature command value TgO by the discharge timing control unit 111d of the control unit 111.
As a result, when it is determined that the exhaust gas temperature Tg is equal to the exhaust gas temperature command value TgO, the ECU 110 ends the ignition timing control process C, and repeatedly shifts the control stage to step S100 (see FIG. 2).
If it is determined that the exhaust gas temperature Tg is not equal to the exhaust gas temperature command value TgO, the ECU 110 shifts the control step to step S350.

In step S350, the ECU 110 determines whether the exhaust temperature Tg stored in the storage unit 111a of the control unit 111 is smaller than the exhaust temperature command value TgO by the discharge timing control unit 111d of the control unit 111.
As a result, when it is determined that the exhaust gas temperature Tg is smaller than the exhaust gas temperature command value TgO, the ECU 110 shifts the control stage to step S360.
If it is determined that the exhaust gas temperature Tg is not smaller than the exhaust gas temperature command value TgO, the ECU 110 shifts the control step to step S370.

  In step S360, the ECU 110 uses the discharge timing control unit 111d of the control unit 111 to determine the discharge angle Deg based on the deviation between the exhaust temperature Tg and the exhaust temperature command value TgO stored in the storage unit 111a and the discharge angle map M3. The angle correction amount DegH is calculated. The ECU 110 corrects the discharge angle Deg to advance by the angle correction amount DegH via the output unit 113 by the discharge timing control unit 111d of the control unit 111, and then ends the ignition timing control process C to perform the control step. Is repeatedly transferred to step S100 (see FIG. 2).

  In step S370, the ECU 110 uses the discharge timing control unit 111d of the control unit 111 to determine the discharge angle Deg based on the deviation between the exhaust temperature Tg and the exhaust temperature command value TgO stored in the storage unit 111a and the discharge angle map M3. The angle correction amount DegH is calculated. The ECU 110 corrects the discharge angle Deg to be retarded by the angle correction amount DegH via the output unit 113 by the discharge timing control unit 111d of the control unit 111, and then ends the ignition timing control process C to perform the control step. Is repeatedly transferred to step S100 (see FIG. 2).

  As described above, the gas engine control device 100, as shown in FIG. 6A, shows the exhaust gas temperature Tg when the air-fuel mixture is combusted with the plug gap of the spark plug 16 expanded due to the change over time, and the change over time. The discharge timing is controlled so that the exhaust temperature Tg when the air-fuel mixture is combusted in a state where the previous plug gap is not enlarged is substantially the same. As a result, as shown in FIG. 6B, the combustion mass ratio (10% −90) which is the combustion time of the air-fuel mixture when the air-fuel mixture is combusted with the plug gap of the spark plug 16 expanded due to change over time. %) (Crank angle until 10% of the fuel gas mass in the mixture burns until 90% burns), when the mixture is burned with the plug gap before the change not expanded It can be made substantially the same as the combustion mass ratio (10% -90%).

Accordingly, as shown in FIG. 7 (a), the gas engine 1 with the discharge angle Deg as Deg0 shortens the combustion time of the air-fuel mixture due to changes over time, so that the exhaust temperature Tg after the X-hour operation is the exhaust temperature. The command value TgO decreases to TgX. At this time, the pressure and temperature of the combustion chamber 14 at the time of combustion become higher and higher than the pressure and temperature of the combustion chamber 14 at the time of combustion before aging due to rapid combustion of the air-fuel mixture due to aging. As a result, the reaction between oxygen and nitrogen in the air-fuel mixture is promoted, and as shown in FIG. 7B, the NOx concentration Ds contained in the exhaust of the gas engine 1 after the operation for X hours is calculated from the target NOx concentration DsT. Increases to DsX.
Here, the gas engine control device 100 retards the discharge angle Deg of the spark plug 16 so that the exhaust temperature Tg rises from TgX to the exhaust temperature command value TgO, as shown in FIG. And Accordingly, the combustion mass ratio (10% -90%) after operation for X hours becomes substantially the same as the combustion mass ratio (10% -90%) before change with time, so that the combustion chamber at the time of combustion of the air-fuel mixture 14 and the temperature are decreased, and as shown in FIG. 7B, the NOx concentration Ds can be decreased from DsX to the target NOx concentration DsT.

Subsequently, as shown in FIG. 7A, in the gas engine 1 in which the discharge angle Deg is DegX, the exhaust temperature Tg after the Y-hour operation decreases from the exhaust temperature command value TgO to TgY. At this time, as shown in FIG. 7B, the NOx concentration Ds contained in the exhaust of the gas engine 1 after the Y-hour operation increases from the target NOx concentration DsT to DsY.
Here, as shown in FIG. 7A, the gas engine control apparatus 100 further delays the discharge angle Deg so that the exhaust temperature Tg rises from TgY to the exhaust temperature command value TgO to be DegY. Accordingly, the combustion mass ratio after operation for Y hours (10% -90%) becomes substantially the same as the combustion mass ratio before change with time (10% -90%), as shown in FIG. 7B. In addition, the NOx concentration Ds can be decreased from DsY to the target NOx concentration DsT.

  Therefore, as shown in FIG. 8, the gas engine control device 100 is configured to provide an air-fuel mixture with an appropriate air-fuel ratio at each net average effective pressure (each engine output) even if the plug gap of the spark plug 16 is expanded due to aging. Is burned and the discharge angle Deg is changed based on the exhaust gas temperature Tg. Therefore, the NOx concentration discharged from the gas engine 1 is maintained substantially the same as before the change with time.

  As described above, the gas engine control apparatus 100 according to the present embodiment includes the mixture temperature detection sensor 130 that is the mixture temperature detection means that detects the mixture temperature Tmix, and the mixture pressure detection means that detects the mixture pressure Pmix. An air-fuel mixture pressure detection sensor 140, an engine speed detection sensor 120 which is an engine speed detection means for detecting the engine speed Ne, and an exhaust temperature detection sensor 150 which is an exhaust temperature detection means for detecting the exhaust temperature Tg. The engine speed command value NeO is determined from the load Ld input to the generator 50, which is a load device driven by the gas engine 1, and the throttle is determined based on the deviation between the engine speed Ne and the engine speed command value NeO. An engine speed control unit 111b which is an engine speed control means for controlling the opening degree of the valve 23; And an air-fuel mixture flow rate command value QmixO from the engine speed command value NeO, and a viscosity-corrected actual air-fuel flow rate QmixR is calculated based on the air-fuel mixture temperature Tmix, the air-fuel mixture pressure Pmix, and the engine speed Ne. A mixture flow rate control unit 111c, which is a mixture flow rate control means for controlling the opening degree of the fuel gas control valve 42 based on the deviation between the flow rate command value QmixO and the viscosity corrected actual mixture flow rate QmixR, and a mixture flow rate command value QmixO A discharge timing control unit 111d, which is a discharge timing control means for determining a timing at which the spark plug 16 discharges based on a deviation between the exhaust temperature command value TgO and the exhaust temperature Tg. To do.

  With this configuration, the viscosity correction actual mixture flow rate QmixR is controlled by controlling the opening degree FvO of the fuel gas control valve 42, and the discharge timing is set so that the exhaust gas temperature Tg becomes a predetermined temperature. By adjusting the discharge angle Deg, the combustion mass ratio (10% -90%) that is the combustion time of the air-fuel mixture can be controlled to a constant value. As a result, even if the ignitability of the air-fuel mixture is improved due to changes over time or the temperature of the combustion chamber 14 in the compression stroke is increased, the pressure and temperature of the combustion chamber 14 during combustion of the air-fuel mixture are increased. It is suppressed. Thereby, the NOx concentration discharged from the gas engine 1 can be maintained at the target NOx concentration DsT.

DESCRIPTION OF SYMBOLS 1 Gas engine 23 Throttle valve 42 Fuel gas control valve 50 Generator 100 Gas engine control apparatus 120 Engine speed detection sensor 130 Mixture temperature detection sensor 140 Mixture pressure detection sensor 150 Exhaust temperature detection sensor Ne Engine rotation speed Tmix Mixture temperature Pmix mixture pressure Tg exhaust temperature Ld load TgO exhaust temperature command value LdO engine output command value NeO engine speed command value GsO fuel gas flow rate command value QmixO mixture flow rate command value QmixR viscosity correction actual mixture flow rate

Claims (1)

A mixture temperature detecting means for detecting the mixture temperature;
A mixture pressure detection means for detecting a mixture pressure;
An engine speed detecting means for detecting the engine speed;
Exhaust temperature detection means for detecting the exhaust temperature;
The engine speed command value is determined from the load applied to the load device driven by the engine, and the opening degree of the throttle valve is controlled based on the deviation between the detected engine speed and the determined engine speed command value. Engine speed control means for
The mixture flow rate command value is determined from the load input to the load device and the determined engine speed command value, and the detected mixture temperature, the detected mixture pressure, and the detected engine speed. A mixture flow rate control means for calculating an actual mixture flow rate based on the difference between the determined mixture flow rate command value and the calculated actual mixture flow rate, and a fuel gas control valve opening degree;
A discharge timing control means for determining an exhaust temperature command value from the determined mixture flow rate command value and controlling a timing at which the spark plug discharges based on a deviation between the determined exhaust temperature command value and the detected exhaust temperature; ,
A gas engine control device comprising:

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