JP2013137036A - Egr control device, egr control method, engine, and engine power generating unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine properly and simply an exhaust gas reflux amount of an engine depending on each engine, in a case where a rotational speed of the engine is controlled to a constant level, and a load of the engine is constant.SOLUTION: An EGR control device includes a state information acquisition unit that acquires state information indicating a state of the rotational speed operating means which is a result of an operation amount which has been given to a rotational speed operating means for adjusting a rotational speed of an engine, so that the rotational speed becomes a certain target value; a state information storage unit that stores the state information acquired by the state information acquisition unit; a state information processing unit, in a case where a load of the engine is constant, that determines a reflux amount of the exhaust gas of the engine to be refluxed to an intake side of the engine from the exhaust side of the engine, based on the state information acquired from the state information storage unit; a state information processing result outputting unit that causes the exhaust gas to reflux with the determined reflux amount; and a state information range storage unit that stores a state information range when a combustion state of the engine is a targeted state.

Description

  The present invention relates to an EGR control device that controls EGR (exhaust gas recirculation) of an engine, a method of controlling EGR of an engine, an engine in which EGR is controlled, and an engine power generation unit.

  Conventionally, EGR devices that recirculate engine exhaust gas to the intake side of the engine have been used to reduce nitrogen oxides in the exhaust gas. A device has been devised that controls the EGR device so that the exhaust gas recirculation amount is optimized in accordance with the changing engine load and the changing engine speed. The EGR device and the method for controlling the EGR device are disclosed in the literature as follows. Japanese Patent Application Laid-Open No. 2004-116427 discloses an EGR device that is applied to an engine-driven air conditioner. This EGR device incorporates an EGR valve driven by a stepping motor, and the opening degree is adjusted by a control device. Engine speed information, throttle valve opening information, and the like are input to the control device, and the control device outputs a control command based on these information to the stepping motor.

  According to Patent Document 2 (Japanese Patent Laid-Open No. 6-280684), two exhaust gas recirculation systems are connected to an automobile engine, and a control valve is provided in one of them. The control valve is interlocked by a throttle valve and a link mechanism to control the exhaust gas recirculation amount.

  Patent Document 3 (Japanese Patent Publication No. 61-48627) discloses an EGR device that is applied to an automobile engine and opens and closes an EGR valve according to the opening of a throttle valve. In this EGR device, exhaust gas recirculation is controlled by opening and closing the EGR valve by opening and closing a plurality of switches based on the engine temperature, the vehicle speed, and the opening of the throttle valve.

JP 2004-116427 A JP-A-6-280684 Japanese Examined Patent Publication No. 61-48627

  On the other hand, when the engine is operated while the load applied to the engine is constant and the engine rotation speed is constant, the combustion state of the engine is set as a target, for example, nitrogen oxides in the exhaust gas are below the target value. The recirculation amount of the exhaust gas suitable for achieving such a state is substantially constant. In this case, the exhaust gas recirculation amount of the engine can be fixed to a constant value without changing the recirculation amount. However, the exhaust gas recirculation amount suitable for setting the combustion state to the target state, for example, the state where the nitrogen oxides in the exhaust gas are below the target value, is the processing error and assembly error even with the same design. Depending on the cause, it differs depending on the individual engine, and even in the same engine due to changes over time such as wear of spark plugs, changes in environmental temperature, fluctuations in components of the supplied fuel, and the like. If the recirculation amount of the exhaust gas from the engine is not set appropriately, the combustion state of the engine may deviate from the target state, and for example, the concentration of nitrogen oxides in the exhaust gas may be higher than the target value. Therefore, the exhaust gas recirculation amount must be adjusted for each engine by setting a value that sets the combustion state to the target state for each engine. However, engine productivity is poor and this leads to an increase in cost. . Further, it may be necessary to readjust the recirculation amount of the exhaust gas in accordance with environmental changes or changes over time even after the start of engine operation, but this makes the management of the engine complicated.

  Accordingly, the present invention has been made in view of the above, and the engine exhaust gas recirculation amount when the engine speed is controlled to be constant and the engine load is constant is appropriately determined according to the individual engine. An object of the present invention is to provide an EGR control device, an EGR control method, an engine, and an engine power generation unit that can be easily determined.

  In order to solve the above-described problems and achieve the object, the EGR control device according to the present invention provides an operation amount to a rotation speed operation means for adjusting the rotation speed of the engine so that the rotation speed becomes a constant target value. The state information acquisition unit that acquires the state information indicating the state of the rotation speed operation means, the state information storage unit that stores the state information acquired by the state information acquisition unit, and the engine A state information processing unit that determines the recirculation amount of the exhaust gas of the engine to be circulated from the exhaust side of the engine to the intake side of the engine based on the state information acquired from the state information storage unit when the load is constant And a state information processing result output unit that recirculates the exhaust gas with the determined recirculation amount. As a result, the rotational speed of the engine is controlled to be constant, and the exhaust gas recirculation amount of the engine when the engine load is constant can be appropriately and easily determined according to the individual engine. The load represents the amount of energy consumed when mechanical energy / electric energy generated by the engine (when mechanical energy is converted into electrical energy by a generator or the like) is consumed.

  The EGR control device according to the present invention further includes a state information range storage unit that stores a state information range when the combustion state of the engine is a target state, and the state information processing unit includes the state information And the state information range, and if the state information is not in the state information range, the return amount is changed so that the state information is within the state information range. Thereby, the exhaust gas recirculation amount of the engine can be determined so that the engine combustion state becomes a target state.

  In the EGR control device according to the present invention, the rotation speed operation means is a fuel supply control valve that adjusts a fuel supply amount to the engine, and the state information is an opening of the fuel supply control valve. When the state information range is an opening range of the fuel supply control valve and the state information processing unit is smaller than a lower limit value of the opening range, the state information processing unit increases the recirculation amount from before the change. When the opening degree is larger than the upper limit value of the opening degree range, the recirculation amount is changed to a smaller value than before the change.

  The EGR control apparatus according to the present invention includes a load rotation speed acquisition unit that acquires the load information of the engine and the rotation speed of the engine, and the load information and the rotation speed acquired by the load rotation speed acquisition unit. A load rotation speed storage unit for storing the load, whether the engine load is constant and the engine rotation speed is constant based on the load information and the rotation speed acquired from the load rotation speed storage unit If the engine load is determined to be constant and the engine speed is determined to be constant, the state information processing unit determines the amount of recirculation, and the engine load is not constant. Alternatively, it may further include a control condition determination unit that determines that the recirculation amount of the exhaust gas is zero when it is determined that the rotational speed of the engine is not constant. Thus, the recirculation amount is determined based on the state information only when the engine load is constant and the engine speed is constant. When the engine load or the engine rotational speed is unstable, the exhaust gas recirculation amount is set to 0, so that the engine operation can be stabilized earlier than when exhaust gas is recirculated.

  The engine according to the present invention includes a rotation speed operation means that adjusts the rotation speed of the engine and gives an operation amount so that the rotation speed becomes a constant target value, and the exhaust gas of the engine is given the operation amount. The engine is recirculated from the exhaust side to the intake side with a recirculation amount determined based on the state information indicating the state of the rotation speed operation means, which is a result of the operation, and is operated with a constant load. Thereby, the recirculation amount of the exhaust gas of the engine operated at a constant rotation speed and load can be determined appropriately and simply.

  The engine according to the present invention further includes a rotation speed operation means that adjusts the rotation speed of the engine so that the operation amount is given so that the rotation speed becomes a constant target value, and the engine exhaust gas is given by the operation amount. The engine is recirculated from the exhaust side to the intake side with a recirculation amount determined based on the state information indicating the state of the rotation speed operation means, which is the result, and the state information is a state targeted by the combustion state of the engine If the state information is not within the state information range, the engine may be operated with a constant load and recirculated with the recirculation amount changed so that the state information is within the state information range. Thereby, the exhaust gas recirculation amount can be determined so that the combustion state of the engine becomes a target state.

  Further, the engine according to the present invention includes a fuel supply control valve for adjusting fuel supply of the engine as the rotational speed operation means for adjusting the rotational speed of the engine, and the state information includes an opening degree of the fuel supply control valve. The state information range is an opening range of the fuel supply control valve, and the exhaust gas of the engine is recirculated from the exhaust side to the intake side with a recirculation amount determined based on the opening, When the opening is smaller than the lower limit of the opening range, the reflux amount is changed to a larger value than before the change, and when the opening is larger than the upper limit of the opening range, the value is smaller than before the change. It may be an engine that is recirculated with a recirculation amount changed to 1 and is operated with a constant load.

  The engine according to the present invention further includes a rotation speed operation means for adjusting the rotation speed of the engine and giving an operation amount so that the rotation speed becomes a constant target value, and from the exhaust side of the engine to the intake side of the engine. An EGR device that recirculates exhaust gas of the engine and has a recirculation amount adjusting unit that adjusts a recirculation amount of the exhaust gas, and the rotation speed operation unit that is a result of giving the operation amount to the rotation speed operation unit A state information acquisition unit that acquires state information indicating the state of the state, a state information storage unit that stores the state information acquired by the state information acquisition unit, and the state information storage when the load on the engine is constant State information for determining the recirculation amount of the exhaust gas of the engine to be circulated from the exhaust side of the engine to the intake side of the engine based on the state information acquired from the section A management unit, and a said state information processing result output section for recirculating the exhaust gas in the recirculation amount determined, characterized in that it comprises a, an EGR control device for controlling the EGR device.

  The engine power generation unit according to the present invention includes a rotation speed operation means that adjusts the rotation speed of the engine and is given an operation amount so that the rotation speed becomes a constant target value. An engine that is recirculated from the exhaust side to the intake side and is operated at a constant load with a recirculation amount determined based on state information indicating the state of the rotation speed operation means that is a given result; and When the engine is connected to the generator and the load of the engine is smaller than the constant load, the power consumption can be greatly changed so that the load of the engine becomes the constant load. Power consumption means. Thereby, the recirculation amount of the exhaust gas of the engine included in the engine power generation unit according to the present invention can be determined appropriately and simply. The engine power generation unit according to the present invention includes power consumption means capable of largely changing power consumption so that the load of the engine becomes the constant load when the load of the engine is smaller than the constant load. Thus, the engine load can be made constant, and as a result, the exhaust gas recirculation amount can be determined based on the state information.

  The engine power generation unit according to the present invention is connected to the engine, a generator driven by the engine, and the generator, and when the load of the engine is smaller than a constant load, the load of the engine is constant. Power consumption means capable of greatly changing the power consumption so as to be a load of the engine, and the engine adjusts the rotational speed of the engine so that the operation amount is adjusted so that the rotational speed becomes a constant target value. A rotation speed operating means provided, an EGR device for recirculating exhaust gas of the engine from an exhaust side of the engine to an intake side of the engine, and having a recirculation amount adjusting means for adjusting a recirculation amount of the exhaust gas; A state information acquisition unit for acquiring state information indicating a state of the rotation speed operation means, which is a result of the operation amount being given to the rotation speed operation means; A state information storage unit for storing the state information acquired by the information acquisition unit; and when the load of the engine is constant, the exhaust information from the exhaust side of the engine based on the state information acquired from the state information storage unit A state information processing unit that determines a recirculation amount of the exhaust gas of the engine to be recirculated to the intake side of the engine, and a state information processing result output unit that recirculates the exhaust gas by the determined recirculation amount; And an EGR control device for controlling.

  The EGR control method according to the present invention is a result of the rotation speed operation means that adjusts the rotation speed of the engine to a rotation speed operation means that gives an operation amount so that the rotation speed becomes a constant target value. The state information acquisition procedure for acquiring the state information indicating the state, the state information storage procedure for storing the state information acquired in the state information acquisition procedure, and the engine load is constant. A state information processing procedure for determining a recirculation amount of the exhaust gas of the engine to be recirculated from the exhaust side of the engine to the intake side of the engine based on the state information stored in the state information storage procedure; And a state information processing result output procedure in which the exhaust gas is recirculated with the determined recirculation amount. Thereby, the recirculation amount of the exhaust gas of the engine that is operated with the rotation speed and the load being constant can be determined appropriately and simply.

  According to the present invention, the exhaust gas recirculation amount of the engine when the rotational speed of the engine is controlled to be constant and the load of the engine is constant can be appropriately and easily determined according to each engine.

FIG. 1 is a control block diagram illustrating a flow of rotational speed control of an example of an engine to which an EGR control device is applied. FIG. 2 is a schematic diagram of an example of an EGR control device and an example of a gas engine to which the EGR control device is applied. FIG. 3 is a schematic diagram for explaining in more detail an example of an ECU functioning as an EGR control device. FIG. 4 is a flowchart showing a part of an example of the flow of EGR control by the EGR control device. FIG. 5 is a flowchart showing an example of the flow of EGR control by the EGR control device. FIG. 6 is a schematic diagram of an example of the engine power generation unit.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following description. In addition, constituent elements in the following description include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range.

[EGR control device]
In an EGR (Exhaust Gas Recirculation) control device according to this embodiment, an operation amount is given to a throttle valve (rotational speed operation means, fuel supply control valve) so that the rotational speed becomes a constant target value. A throttle valve opening acquisition unit (state information acquisition unit, opening acquisition unit) for acquiring the throttle valve opening (state information, fuel supply control valve opening) indicating the state of the throttle valve as a result of The throttle valve opening degree storage unit (state information storage unit, opening degree storage unit) that stores the throttle valve opening degree acquired by the throttle valve opening degree acquisition unit, and the throttle valve opening degree when the engine load is constant A throttle valve opening processing unit (state information processing unit, opening degree) that determines the recirculation amount of the exhaust gas of the engine to be recirculated from the engine exhaust side to the engine intake side based on the throttle valve opening acquired from the storage unit And a throttle valve opening processing result output unit (state information processing result output unit, opening processing result output unit) that recirculates the exhaust gas with the determined recirculation amount.

  FIG. 1 is a control block diagram for explaining the flow of rotational speed control of an engine to which the EGR control device according to this embodiment is applied. FIG. 2 is a schematic diagram of an EGR control device according to the present embodiment and a gas engine to which the EGR control device is applied. The engine to which the EGR control device according to the present embodiment is applied is controlled so that the rotational speed becomes a constant target value as follows. First, the flow of rotational speed control will be described with reference to FIG.

  A target value Net of the engine rotation speed is given to the gas engine 17 to be controlled. The target value is 1600 rpm, for example. A controller of an ECU (Engine Control Unit) 11 obtains a deviation ΔNe (= Net−Ne) between the target value Net and an observed value Ne of the engine speed observed from the gas engine 17. Then, the controller determines an operation amount of the throttle valve 9 which is an amount for operating the opening degree of the throttle valve 9 so that the deviation ΔNe becomes zero.

  For example, a PI controller is used as the controller. The PI controller may be configured with dedicated hardware using an operational amplifier, a resistor, a capacitor, or the like, or may be configured as software executed by the ECU 11. The ECU 11 outputs the operation amount of the throttle valve 9 to the actuator 10 of the throttle valve 9 of the gas engine 17, and the actuator 10 drives the throttle valve 9 by the output operation amount to change the opening degree of the throttle valve 9. The opening degree of the throttle valve 9 represents the state of the throttle valve 9 as a result of the operation amount being given to the throttle valve 9 which is the rotation speed operation means. By this control, the rotation speed of the gas engine 17 is held at a constant target value. That is, an operation amount is given to the throttle valve 9 which is the rotation speed operation means so that the rotation speed of the gas engine 17 becomes a constant target value.

  The engine to which the EGR control device according to the present embodiment is applied will be described as a gas engine. However, the engine to which the EGR control device according to the present invention is applied is not limited to a gas engine, and is applicable to all engines that perform exhaust gas recirculation. The EGR control device according to the present invention can be applied. However, since the gas engine can use the gas supplied to ordinary households as fuel, it is easy to supply the fuel and can be easily installed in ordinary households. Suitable for incorporation into household equipment such as generation systems. Therefore, when the EGR control device of the present invention is incorporated into household equipment, the EGR control device according to the present invention is preferably applied to a gas engine, and the engine according to the present invention is preferably a gas engine.

  Connected to the engine body 2 are an intake pipe 3 for intake of a mixture of fuel gas and air on the intake side, and an exhaust pipe 4 for exhausting exhaust gas Ex generated after engine combustion on the exhaust side. An EGR pipe 5 is provided by connecting an intermediate part of the intake pipe 3 and an intermediate part of the exhaust pipe 4. The EGR pipe 5 guides the exhaust gas flowing through the exhaust pipe 4 to the intake pipe 3 and recirculates the exhaust gas to the engine body 2. The recirculation amount of the exhaust gas Ex can be controlled by adjusting the opening degree of the EGR valve 6 (reflux amount adjusting means) provided in the middle of the EGR pipe 5. As the EGR valve 6, for example, a needle valve, a butterfly valve, a solenoid valve or the like is used.

  An actuator 7 is incorporated in the EGR valve 6, and the EGR valve 6 is driven to change its opening. The actuator 7 functions as a state information processing result output unit and an opening degree processing result output unit that recirculate the exhaust gas Ex with the determined recirculation amount. A stepping motor or the like can be used as the actuator 7. The intake pipe 3 of the engine body 2 includes a mixer 8 that mixes air and fuel gas, and a throttle valve 9 that adjusts the flow rate of the mixture of air and fuel mixed in the mixer 8 to the engine body 2. It is connected. As the throttle valve 9, for example, a needle valve, a butterfly valve, a solenoid valve or the like is used.

  The exhaust gas Ex introduced from the EGR pipe 5 joins the air-fuel mixture sent through the throttle valve 9 and is sent to the combustion chamber of the engine body 2. An actuator 10 is incorporated in the throttle valve 9, and the throttle valve 9 is driven to change its opening.

  When the throttle valve or the EGR valve is controlled by being fully opened and fully closed, such as when the throttle valve or EGR valve is a duty solenoid valve, the opening degree is expressed as a ratio of the valve opening time to a certain time. .

  An ECU 11 is connected to the actuator 10 of the throttle valve 9 and the actuator 7 of the EGR valve 6. The ECU 11 and the actuator 7 constitute the EGR control device 1. The ECU 11 controls the operation of the engine body 2 and functions as a part of the EGR control device 1 of the present embodiment. An operation amount of the throttle valve 9 and an opening command (opening result) of the EGR valve 6 are sent from the ECU 11 to the actuators 7 and 10. The ECU 11 is connected to a rotation speed detecting means 12 of the engine body 2, and the rotation speed detected from the engine body 2 is sent to the ECU 11. Further, the ECU 11 is connected to a wattmeter 13 which is a load detection means of the gas engine 17, and measures electric power consumed by a circuit to which a generator (not shown) driven by the gas engine 17 is connected. Yes. The power consumption measured by the wattmeter 13 represents the magnitude of the load on the generator. In the case of the gas engine 17 whose output is used only to drive the generator, the power consumption is constant. May be when the load of the gas engine 17 is constant.

  The ECU 11 includes an interface unit 14, a storage unit 15, and a processing unit 16. The interface unit 14 is connected to the actuators 7, 10, the rotational speed detection means 12, and the wattmeter 13, and enables communication of information with the storage unit 15 and the processing unit 16. The storage unit 15 includes a hard disk device, a magneto-optical disk device, a nonvolatile memory such as a flash memory, a readable storage medium such as a CD-ROM, and a volatile memory such as a RAM (Random Access Memory). It is configured by a memory or a combination thereof. Further, the storage unit 15 may be in another device (database server) other than the one built in the EGR control device 1, and the EGR control device 1 may access the storage unit 15 by communication.

  The processing unit 16 includes a memory and a CPU (Central Processing Unit). Even if the processing unit 16 is realized by dedicated hardware, the function (not shown) for realizing the function of the processing unit 16 is loaded into the memory of the processing unit 16 and executed to execute the function. It may be realized.

  FIG. 3 is a schematic diagram for explaining the ECU that functions as a part of the EGR control device in more detail. The processing unit 16 of the ECU 11 that functions as a part of the EGR control device 1 includes a throttle valve opening degree acquisition unit 18, a throttle valve opening degree processing unit 19, a load rotation speed acquisition unit 20, and a control condition determination unit 21. Consists of including. The storage unit 15 of the ECU 11 includes a throttle valve opening degree storage unit 22, a throttle valve opening range storage unit 23, and a load rotation speed storage unit 24.

  The load rotation speed acquisition unit 20 acquires the load information of the gas engine 17 and the rotation speed of the gas engine 17. The load rotation speed storage unit 24 stores the load information and the rotation speed acquired by the load rotation speed acquisition unit 20. The control condition determination unit 21 determines whether the load of the gas engine 17 is constant and the rotation speed of the gas engine 17 is constant based on the load information and the rotation speed acquired from the load rotation speed storage unit 24. When the determination is made and it is determined that the load of the gas engine 17 is constant and the rotational speed of the gas engine 17 is constant, the throttle valve opening processing unit 19 determines the exhaust gas Ex based on the opening of the throttle valve 9. When the recirculation amount is determined and it is determined that the load of the gas engine 17 is not constant or the rotation speed of the gas engine 17 is not constant, the recirculation amount of the exhaust gas Ex is determined to be zero.

  The throttle valve opening degree acquisition unit 18 acquires the opening degree of the throttle valve 9. The throttle valve opening degree storage unit 22 stores the throttle valve opening degree acquired by the throttle valve opening degree acquisition unit 18. The throttle valve opening range storage unit 23 stores a throttle valve opening range when the combustion state of the gas engine 17 is a target state. When the engine load is constant, the throttle valve opening degree processing unit 19 recirculates from the engine exhaust side to the engine intake side based on the throttle valve opening obtained from the throttle valve opening degree storage unit 22. The recirculation amount of the exhaust gas Ex is determined.

  FIG. 4 is a flowchart showing a part of the flow of EGR control by the EGR control device 1 according to the present embodiment. The flow of control by the EGR control device 1 will be described below. First, the power consumption (load) measured by the wattmeter 13 (load detection means) and the rotation speed detected by the rotation speed detection means 12 for detecting the rotation speed of the engine, such as a crank angle sensor or a cam angle sensor, are obtained. The load rotation speed acquisition unit 20 in the processing unit 16 acquires via the interface unit 14 (step S1). The power consumption and rotation speed acquired by the load rotation speed acquisition unit 20 are stored in the load rotation speed storage unit 24 in the storage unit 15.

  Next, the control condition determination unit 21 in the processing unit 16 acquires the power consumption and the rotation speed from the load rotation speed storage unit 24, and determines whether the power consumption is constant and the rotation speed is constant. (Step S2). The determination of whether or not it is constant is made by comparing the acquired power consumption and rotation speed with the target power consumption value and rotation speed stored in the storage unit 15 in advance.

  When the control condition determination unit 21 in the processing unit 16 determines that the power consumption (load) is not constant or the rotation speed is not constant (step S2: No), the control condition determination unit 21 sets the exhaust gas recirculation amount to 0. And a command to set the opening of the EGR valve to 0 is sent to the actuator 7 of the EGR valve 6 (step S5). The actuator 7 drives the EGR valve 6 according to the command so that the opening degree of the EGR valve 6 becomes zero.

  When the control condition determination unit 21 determines that the power consumption is constant and the rotation speed is constant (step S2: Yes), the throttle valve opening processing unit 19 recirculates based on the throttle valve opening. Is determined (step S3). Next, the control condition determination unit 21 determines whether the operation of the gas engine 17 is ended or continued (step S4). When the control condition determination unit 21 determines that the operation of the gas engine 17 is continued (step S4: No), the process returns to step S1, and the load information and the rotation speed are acquired again. When the control condition determination unit 21 determines that the operation of the gas engine 17 is ended (step S4: Yes), the control is ended.

  Since the EGR control device 1 includes the load rotation speed acquisition unit 20, the load rotation speed storage unit 24, and the control condition determination unit 21, the throttle valve opening degree is obtained only when the load is constant and the rotation speed is constant. The amount of reflux can be determined based on Here, an example has been described in which the control condition determination unit 21 determines that the exhaust gas recirculation amount is 0 when the power consumption (load) is not constant or the rotation speed is not constant. The reflux amount may be set to another appropriate value.

  FIG. 5 is a flowchart showing a control procedure when the throttle valve opening degree processing unit 19 determines the recirculation amount based on the throttle valve opening degree. When the control condition determination unit 21 determines that the recirculation amount is determined based on the throttle valve opening (step S3), the processing unit 16 performs control to determine the recirculation amount based on the throttle valve opening (step 3). ) Is started for the first time (whether it is the first control start) or not (step S6). When the processing unit 16 determines that the control start is the first time (step S6: Yes), the processing unit 16 sends an initial value of the opening degree of the EGR valve 6 (EGR valve opening degree) to the actuator 7 of the EGR valve 6. Output). The initial value of the EGR valve opening is such that the combustion state of the gas engine 17 becomes a target state under the condition that the load of the gas engine 17 is constant and the rotation speed of the gas engine 17 is constant. It is determined in advance by simulation or an experiment using a gas engine having the same design as the gas engine 17 to which the EGR control device 1 is applied.

  The target state is a state in which, for example, the amount of nitrogen oxide in the exhaust gas Ex becomes a reference value or less. The determined initial value of the EGR valve opening is stored in the storage unit 15. Alternatively, the opening degree of the EGR valve 6 last determined by the throttle valve opening degree processing unit 19 may be stored in the storage unit 15 as an EGR valve opening initial value in the next control. The processing unit 16 acquires the EGR valve opening initial value stored in the storage unit 15 and instructs the actuator 7 of the EGR valve 6 to output the EGR valve opening initial value, and the actuator 7 receives the EGR valve 6. The EGR valve 6 is driven so that the opening degree becomes the initial value (step S7). If the processing unit 16 determines that it is not the first time that the control for determining the recirculation amount is started based on the throttle valve opening (step S6: No), step S7 is not performed and the next step S8 ( The procedure proceeds to (to be described later). In this case, not the initial value of the EGR valve opening, but the value of the opening of the EGR valve 6 determined based on the throttle valve opening during the previous control is output.

  After the opening degree of the EGR valve 6 becomes the initial value or the value determined at the time of the previous control, the throttle valve opening degree obtaining part 18 in the processing part 16 obtains the throttle valve opening degree (step S8). The throttle valve opening degree acquiring unit 18 acquires the throttle valve opening degree from a sensor that detects the opening degree installed in the throttle valve 9 or uses the drive history of the actuator 10 of the throttle valve 9 to acquire the throttle valve opening degree acquiring unit. 18 is obtained by calculating or the like. When the actuator 10 is a stepping motor, the throttle valve opening is the sum of the operation amounts given to the stepping motor after the engine is started. The throttle valve opening can be acquired at an arbitrary sampling interval, for example, an interval of 50 milliseconds. The throttle valve opening degree acquired by the throttle valve opening degree acquisition unit 18 is stored in the throttle valve opening degree storage unit 22 (step S9).

  The throttle valve opening degree processing unit 19 determines the opening degree of the EGR valve 6 based on the throttle valve opening degree acquired from the throttle valve opening degree storage unit 22 (step S10), and the throttle valve opening degree processing unit 19 determines the opening degree. The opening degree of the EGR valve 6 is commanded to the actuator 7. Here, when the gas engine 17 is operated at a constant rotational speed and the load of the gas engine 17 is constant, the throttle valve opening, which is state information indicating the state of the rotational speed operating means, is the combustion state of the engine. It becomes an index. Accordingly, the opening degree of the EGR valve 6 is determined based on the throttle valve opening degree, and the exhaust gas recirculation amount is determined, so that the exhaust gas recirculation amount is appropriately determined according to the combustion state of the engine.

Even with the same engine design, there are variations due to processing errors and assembly errors, and even with the same engine, the appropriate recirculation amount of the exhaust gas Ex differs due to changes over time, component variations of the supplied fuel, and the like. However, the throttle valve opening processing unit 19 determines the amount of exhaust gas recirculation according to the combustion state of the engine, thereby suppressing fluctuations in the amount of nitrogen oxides present in the engine exhaust gas. Further, since an additional device such as an O ₂ sensor for grasping the combustion state of the engine is not necessary, the amount of exhaust gas recirculated can be easily adjusted.

  Based on the rotational speed, the throttle valve opening processing unit 19 determines the opening degree of the EGR valve 6 based on the throttle valve opening degree, not the rotational speed of the gas engine 17, that is, the recirculation amount of the exhaust gas Ex. Thus, the gas engine 17 can be operated more stably than when the opening degree of the EGR valve 6 is determined. This is due to the following reason. The rotational speed of the gas engine 17 reacts sensitively to disturbances such as temperature, air-fuel ratio, and load fluctuations. In this case, when a command to increase or decrease the opening degree of the throttle valve 9 is given as an operation amount to the actuator 10 of the throttle valve 9 so that the deviation between the detected rotation speed and the target rotation speed is zero, the operation amount is The opening degree (state information) of the throttle valve 9 which is a given result reflects the control state of the engine rotational speed after the engine is started, and does not react as sensitively to disturbance as the rotational speed. Because.

  Next, the procedure (step S10) in which the throttle valve opening degree processing unit 19 determines the opening degree of the EGR valve 6 will be specifically described. The throttle valve opening processing unit 19 obtains the acquired throttle valve opening, and the throttle valve opening range (state information range, fuel supply control valve opening range) when the combustion state of the engine is the target state. Compare As the throttle valve opening range when the combustion state of the engine is a target state, for example, a range is set such that the amount of nitrogen oxides present in the exhaust gas Ex of the engine is below a reference value. The throttle valve opening range is determined in advance by simulation or an experiment using a gas engine having the same design as the gas engine 17 under the condition that the engine load is constant and the rotational speed is constant. The throttle valve opening range is, for example, 68 ± 7% (100% when fully opened). The determined throttle valve opening range is stored in the throttle valve opening range storage unit 23.

  The throttle valve opening processing unit 19 acquires the throttle valve opening range from the throttle valve opening range storage unit 23, and compares the throttle valve opening and the throttle valve opening range. When the throttle valve opening is not in the throttle valve opening range, the throttle valve opening processing unit 19 changes the opening of the EGR valve 6 so that the throttle valve opening is within the throttle valve opening range, The opening degree is commanded to the actuator 7 of the EGR valve 6, and the actuator 7 outputs the opening degree of the EGR valve 6.

In this way, the throttle valve opening processing unit 19 changes the opening of the EGR valve 6 so that the throttle valve opening falls within a preset throttle valve opening range, whereby exhaust gas is burned by the engine. It is possible to appropriately recirculate with a recirculation amount such that the state is a target state, for example, a recirculation amount such that the amount of nitrogen oxides in the exhaust gas Ex of the engine becomes a reference value or less. Further, it is simple because it is not necessary to observe the exhaust gas component with an O ₂ sensor or the like.

  The throttle valve opening processing unit 19 compares the throttle valve opening and the lower limit value of the throttle valve opening range (step S10a), and determines that the throttle valve opening is smaller than the lower limit value of the throttle valve opening range. In this case (step S10a: Yes), since the fuel is richer than the target combustion state, the throttle valve opening processing unit 19 determines to increase the opening of the EGR valve 6 (step S10b), the actuator 7 is commanded to increase the opening of the new EGR valve 6.

  When the throttle valve opening processing unit 19 determines that the throttle valve opening is equal to or greater than the lower limit value of the throttle valve opening range (step S10a: No), the throttle valve opening and the throttle valve opening range The upper limit value is compared (step S10c). When the throttle valve opening degree processing unit 19 determines that the throttle valve opening degree is equal to or less than the upper limit value of the throttle valve opening range (step S10c: Yes), the throttle valve opening degree processing unit 19 determines that the EGR valve 6 It is determined to maintain the opening degree (step S10d).

  When the throttle valve opening processing unit 19 determines that the throttle valve opening is larger than the upper limit value of the throttle valve opening range (step S10c: No), the fuel is leaner than the target combustion state. Therefore, the throttle valve opening degree processing unit 19 decides to reduce the opening degree of the EGR valve 6 (step S10e), and commands the actuator 7 to set the new opening degree of the EGR valve 6. The actuator 7 which is a throttle valve opening processing result output unit receives a command for maintaining or increasing the opening of the EGR valve 6 from the throttle valve opening processing unit 19, and changes the valve opening of the EGR valve 6. The EGR valve opening is adjusted according to the command (step S11).

  In addition, although the throttle valve opening processing part 19 demonstrated the example which compares a throttle valve opening and the lower limit of a throttle valve opening range first, the order of a comparison does not ask | require a throttle valve opening first. The upper limit value of the throttle valve opening range may be compared. Further, the throttle valve opening processing unit 19 may compare the throttle valve opening value acquired by the throttle valve opening acquisition unit 18 using the value of the throttle valve opening as it is. An average value of the opening degree may be obtained and compared with the throttle valve opening range, and the throttle valve opening degree may be determined every arbitrary time.

  For example, the throttle valve opening degree processing unit 19 acquires the throttle opening degree acquired by the throttle valve opening degree acquiring unit 18 for 5 seconds at a sampling interval of 50 ms from the throttle valve opening degree acquiring unit 18 and calculates an average value thereof. The average value and the throttle valve opening range may be compared every second. By comparing the average value and the throttle valve opening range, even if the throttle valve opening acquired by the throttle valve opening acquisition unit 18 has an abnormal value, the opening of the EGR valve 6 affects the abnormal value. It becomes difficult to be done. It is also possible to increase / decrease the time for taking the average value and change the reaction speed of the increase / decrease of the opening of the EGR valve 6 relative to the increase / decrease of the throttle valve opening.

  After the valve opening of the EGR valve 6 is adjusted to the EGR valve opening corresponding to the command (step S11), the throttle valve opening processing unit 19 determines the recirculation amount based on the throttle valve opening (step S3). ) Ends, and the process proceeds to step S4.

  When the control condition determination unit 21 determines that the rotation speed of the gas engine 17 is not constant or the load of the gas engine 17 is not constant, the throttle valve opening degree processing unit 19 is based on the throttle valve opening degree. The EGR valve opening is not determined. As a result, it is possible to avoid further unstable operation of the engine by not changing the exhaust gas circulation rate in an unstable operation situation. In this case, the control condition determination unit 21 determines the opening degree of the EGR valve 6 to 0, and instructs the actuator 7 to set the opening degree to 0. The actuator 7 drives the EGR valve 6 to turn the EGR valve 6 on. Fully closed.

  Here, the control condition determination unit 21 may set the opening of the EGR valve 6 to an appropriate value other than 0, but it is preferable to determine it as 0. The control condition determination unit 21 can stabilize the operation of the engine earlier than when the exhaust gas is recirculated by setting the opening of the EGR valve 6 to 0 in an unstable driving situation. Further, when it is determined that the rotational speed is not constant or the load is not constant, the EGR control device 1 connects the throttle valve opening degree processing unit 19 to the control condition judgment unit 21 and the throttle valve opening degree processing unit 19. You may have the process selection part which issues the command which gives priority to the determination of the exhaust gas recirculation amount by the control condition judgment part 21 rather than the determination of the exhaust gas recirculation amount by. The processing selection unit may be a part of the function of the processing unit 16 or may be an element different from the processing unit 16 such as an interrupt controller.

  As described above, the EGR control apparatus 1 according to this embodiment controls the exhaust gas recirculation amount of the gas engine 17 when the rotation speed of the gas engine 17 is controlled to be constant and the load of the gas engine 17 is constant. It can be determined appropriately and conveniently according to the 17 individual differences.

  In the EGR control device 1 according to the present embodiment described above, the opening degree of the EGR valve 6 is determined based on the opening degree of the throttle valve 9, but in addition to the throttle valve, fuel and air are used as the engine speed operation means. Other fuel supply adjusting means for adjusting the supply amount of the fuel by adjusting the supply amount of the mixture of fuel and air after mixing the fuel, the fuel for adjusting the supply amount of the fuel before mixing the fuel and air When the supply amount of fuel is determined according to the supply adjustment means and the amount of air, an air amount adjustment means, a fuel injection valve, or the like may be applied. Then, as a result of the operation amount being given to these rotational speed operation means, the supply amount of the air-fuel mixture, the fuel supply amount, the air amount, the numerical value as the index of the fuel supply amount, the numerical value as the index of the air amount, the valve The recirculation amount of the exhaust gas may be determined based on the degree of opening.

〔engine〕
The engine according to the present embodiment includes a throttle valve (rotation speed operation means, fuel supply adjustment valve) that adjusts the rotation speed of the engine and gives an operation amount so that the rotation speed becomes a constant target value. Is a recirculation amount determined based on the throttle valve opening (state information), which is the result of the operation amount being given, and is a gas engine that recirculates from the exhaust side to the intake side and is operated at a constant load. is there.

  More specifically, the engine according to the present embodiment has a throttle valve, and recirculates the exhaust gas of the engine from the exhaust side of the engine to the intake side of the engine, and adjusts the recirculation amount of the exhaust gas. This is a gas engine 17 including an EGR device having a valve 6 (reflux amount adjusting means) and the EGR control device according to the above-described embodiment. Since the gas engine 17 according to the present embodiment has been described together with the description of the EGR control device 1, the description thereof will be omitted. Since the gas engine 17 can circulate the exhaust gas with a recirculation amount determined appropriately and simply and includes the EGR control device 1, the gas engine 17 has the effect of the EGR control device according to the above-described embodiment.

[Engine power generation unit]
The engine power generation unit according to the present embodiment includes a throttle valve (rotational speed operation means), and the exhaust gas of the engine flows from the exhaust side to the intake side with a recirculation amount determined based on the throttle valve opening (state information). A gas engine that is refluxed and operated at a constant load, a generator that is driven by the gas engine, and a generator that is connected to the generator and the load of the gas engine is smaller than the constant load, the load of the gas engine is And an electric heater (power consumption means) that can greatly change the power consumption so as to achieve the constant load. More specifically, the gas engine included in the engine power generation unit according to the present embodiment includes the EGR control device 1 according to the above-described embodiment.

  FIG. 6 is a schematic diagram of the engine power generation unit according to the present embodiment. The engine power generation unit 25 includes an engine body 2 of the gas engine 17, an ECU 11 that also functions as a part of the EGR control device 1, a throttle valve 9, an electric heater 26, and a generator 27. Hereinafter, the engine power generation unit 25 will be described with reference to FIG.

  The fuel gas is introduced into the governor 28 from the outside through the electromagnetic valve 32. After the pressure is adjusted by the governor 28, the fuel gas is mixed with air by the mixer 8, the flow rate is adjusted by the throttle valve 9, and then supplied to the engine body 2. The exhaust gas discharged from the engine body 2 is subjected to heat exchange with the engine cooling water in the exhaust gas heat exchanger 29 to be lowered in temperature, and then partly merges with the fuel gas through the EGR valve 6 to return to the engine body 2. The remaining exhaust gas that is not recirculated passes through a silencer (not shown) and is then discharged to the outside of the engine power generation unit 25. The engine cooling water is used to cool the engine main body 2 after exchanging heat with the exhaust gas. When the electric heater 26 is energized thereafter, the engine cooling water is heated by the electric heater 26 and is external to the engine power generation unit 25. Spill to

  A generator 27 is connected to the engine body 2 to generate AC power. The generated electric power is converted into AC power synchronized with the system power supply by the inverter unit 30 and connected to the system power supply outside the engine power generation unit 25. The generated AC power is consumed by the external load 31 outside the engine power generation unit 25. The gas engine 17 is rated at a constant rotational speed. When the power consumption of the external load 31 is larger than the power generation amount during the rated operation, power is supplied from the system power source to the external load 31, and when it is small, surplus power is sent to the electric heater 26 and consumed by the electric heater 26. The Since the engine power generation unit 25 includes the electric heater 26 (power consumption means) that consumes surplus power, the load on the generator 27 is constant, and the load on the gas engine 17 that drives the generator 27 is also constant. It becomes constant. Since the load of the gas engine 17 is constant, the ECU 11 functioning as a part of the EGR control device can determine the circulation amount of the exhaust gas based on the throttle valve opening.

  The total load of the generator 27 that combines the power consumption of the external load 31 and the power consumption of the electric heater 26 is measured by the wattmeter 13 in the inverter unit 30. This measured value is sent to the ECU 11 and used for control by the ECU 11 functioning as an EGR control device. The ECU 11 is connected to the electromagnetic valve 32, the actuator 10 of the throttle valve 9, the actuator 7 of the EGR valve 6, and the rotation speed detection means 12. Although not shown, the ECU 11 includes an exhaust gas temperature sensor, an engine oil temperature sensor, a hydraulic switch, an engine spark plug, a cooling water temperature sensor after cooling the engine, and a cooling water temperature after heating by the electric heater 26. A gas engine is controlled by being connected to a sensor or the like. Since the gas engine 17 and the EGR control device 1 included in the engine power generation unit 25 have been described above, description thereof will be omitted.

  Since the engine power generation unit 25 can circulate the exhaust gas at a recirculation amount determined appropriately and simply and includes the gas engine according to the above-described embodiment, the engine power generation unit 25 includes the gas engine according to the above-described embodiment. Has an effect.

[EGR control method]
The EGR control method according to the present embodiment is a result of the rotation speed operation means being a result of giving an operation amount to the rotation speed operation means for adjusting the rotation speed of the engine so that the rotation speed becomes a constant target value. A state information acquisition procedure in which state information indicating a state is acquired; a state information storage procedure in which the state information acquired in the state information acquisition procedure is stored; and when the engine load is constant, the state A state information processing procedure in which a recirculation amount of the exhaust gas of the engine to be circulated from the exhaust side of the engine to the intake side of the engine is determined based on the state information stored in the information storage procedure; and the determined recirculation amount And a state information processing result output procedure in which the exhaust gas is recirculated.

  Although more specific description will be given with reference to FIG. 5, the description overlapping with the description of the EGR control device 1 is omitted. In the throttle valve opening degree obtaining procedure S8 (state information obtaining procedure), the throttle valve opening degree obtaining unit 18 gives the operation amount to the rotational speed operation means so that the rotational speed becomes a constant target value. The valve opening is acquired. Next, in the throttle valve opening degree storage procedure S9 (state information storage procedure), the throttle valve opening degree storage unit 22 stores the throttle valve opening degree acquired in the throttle valve opening degree acquisition procedure S8. In the throttle valve opening processing procedure S10, when the engine load is constant by the throttle valve opening processing unit 19, the recirculation amount of the exhaust gas based on the throttle valve opening stored in the throttle valve opening storing procedure S9. Is determined. In the throttle valve opening processing result output procedure S11 (state information processing result output procedure), the exhaust gas is recirculated by the determined recirculation amount by the actuator 7 of the EGR valve 6 as the throttle valve opening output unit.

With the EGR control method according to the present embodiment, the exhaust gas recirculation amount is determined based on the throttle valve opening, so that the exhaust gas recirculation amount is appropriately determined according to the combustion state of the engine. By determining the recirculation amount of the exhaust gas according to the combustion state of the engine, it is possible to avoid fluctuation of the amount of nitrogen oxide in the exhaust gas of the engine. Further, since an additional device such as an O ₂ sensor for grasping the combustion state of the engine is not required, the recirculation amount of the exhaust gas can be easily adjusted.

  In the EGR control method according to another embodiment, in the state information processing procedure, the state information is compared with the state information range when the combustion state of the engine is the target state, and the state information is included in the state information range. If not, the exhaust gas recirculation amount is changed so that the state information is within the state information range.

  This will be described more specifically with reference to FIG. A description overlapping with the EGR control method according to the above-described embodiment will be omitted. The throttle valve opening range storage unit 23 (state information range storage unit) stores a throttle valve opening range (state information range) when the engine combustion state is a target state. In the throttle valve opening processing procedure S10 (state information processing procedure), the throttle valve opening processing unit 19 acquires the throttle valve opening range from the throttle valve opening range storage unit 23, and the throttle valve opening and throttle valve The opening range is compared (step S10a, step S10c). Next, when the throttle valve opening is not within the throttle valve opening range, a determination is made to increase or decrease the exhaust gas recirculation amount so that the throttle valve opening is within the throttle valve opening range (steps S10b and S10e).

With the EGR control method according to this embodiment, the amount of recirculation of exhaust gas such that the combustion state of the engine is a target, for example, the amount of nitrogen oxides present in the exhaust gas of the engine is below a reference value. It can be appropriately refluxed with a reflux amount. Further, it is simple because it is not necessary to observe the exhaust gas component with an O ₂ sensor or the like.

  As described above, the EGR control device, the EGR control method, the engine, and the engine power generation unit according to the present invention are useful for determining the exhaust gas recirculation amount appropriately and simply according to each engine. .

DESCRIPTION OF SYMBOLS 1 EGR control apparatus 2 Engine main body 3 Intake pipe 4 Exhaust pipe 5 EGR pipe 6 EGR valve 7 Actuator 8 Mixer 9 Throttle valve 10 Actuator 12 Rotational speed detection means 13 Wattmeter 14 Interface section 15 Storage section 16 Processing section 17 Gas engine 18 Throttle Valve opening acquisition unit 19 Throttle valve opening processing unit 20 Load rotation speed acquisition unit 21 Control condition determination unit 22 Throttle valve opening storage unit 23 Throttle valve opening range storage unit 24 Load rotation speed storage unit 25 Engine power generation unit 26 Electric heat Heater 27 Generator 28 Governor 29 Exhaust gas heat exchanger 30 Inverter unit 31 External load 32 Solenoid valve S8 Throttle valve opening acquisition procedure S9 Throttle valve opening storage procedure S10 Throttle valve opening processing procedure S11 Throttle valve opening processing result output Order

Claims (6)

A rotational speed operation means for adjusting the rotational speed of the engine and giving an operation amount so that the rotational speed becomes a constant target value;
An EGR device that recirculates the exhaust gas of the engine from the exhaust side of the engine to the intake side of the engine, and having a recirculation amount adjusting means for adjusting a recirculation amount of the exhaust gas;
A state information acquisition unit that acquires state information indicating a state of the rotation speed operation unit, which is a result of the operation amount being given to the rotation speed operation unit, and the state information acquired by the state information acquisition unit are stored. The engine exhaust gas to be recirculated from the exhaust side of the engine to the intake side of the engine based on the state information acquired from the state information storage unit when the load of the engine is constant. A state information processing unit that determines a recirculation amount, a state information processing result output unit that recirculates the exhaust gas with the determined recirculation amount, and a state information range when the combustion state of the engine is a target state A state information range storage unit for storing, wherein the rotational speed operation means is a fuel supply control valve that adjusts the amount of fuel supplied to the engine, and the state information is The opening degree of the fuel supply control valve, the state information range is an opening range of the fuel supply control valve, and the state information processing unit includes the opening degree of the fuel supply control valve and the fuel supply control valve. When the opening is smaller than the lower limit value of the opening range, the reflux amount is changed to a larger value than before the change, and the opening is the upper limit value of the opening range. An EGR control device that controls the EGR device to change the reflux amount so that the opening degree is within the opening degree range by changing the reflux amount to a smaller value than before the change when larger than ,
An engine characterized by including.   The engine load according to claim 1, wherein the engine load is determined by power consumption. Engine,
A generator driven by the engine;
Power consumption means connected to the generator and capable of greatly changing power consumption so that the load of the engine becomes the constant load when the load of the engine is smaller than the constant load;
Including
The engine is
A rotation speed operation means for adjusting the rotation speed of the engine and giving an operation amount so that the rotation speed becomes a constant target value;
An EGR device that recirculates the exhaust gas of the engine from the exhaust side of the engine to the intake side of the engine, and having a recirculation amount adjusting means for adjusting a recirculation amount of the exhaust gas;
A state information acquisition unit that acquires state information indicating a state of the rotation speed operation unit, which is a result of the operation amount being given to the rotation speed operation unit, and the state information acquired by the state information acquisition unit are stored. The engine exhaust gas to be recirculated from the exhaust side of the engine to the intake side of the engine based on the state information acquired from the state information storage unit when the load of the engine is constant. A state information processing unit that determines a recirculation amount, a state information processing result output unit that recirculates the exhaust gas with the determined recirculation amount, and a state information range when the combustion state of the engine is a target state A state information range storage unit for storing, wherein the rotational speed operation means is a fuel supply control valve that adjusts the amount of fuel supplied to the engine, and the state information is The opening degree of the fuel supply control valve, the state information range is an opening range of the fuel supply control valve, and the state information processing unit includes the opening degree of the fuel supply control valve and the fuel supply control valve. When the opening is smaller than the lower limit value of the opening range, the reflux amount is changed to a larger value than before the change, and the opening is the upper limit value of the opening range. An EGR control device that controls the EGR device to change the reflux amount so that the opening degree is within the opening degree range by changing the reflux amount to a smaller value than before the change when larger than ,
An engine power generation unit comprising:   The engine power generation unit according to claim 3, wherein the engine load is determined by power consumption. State information indicating the state of the rotation speed operation means is acquired as a result of the operation amount being given to the rotation speed operation means for adjusting the rotation speed of the engine so that the rotation speed becomes a constant target value. Status information acquisition procedure;
A status information storage procedure in which the status information acquired in the status information acquisition procedure is stored;
When the engine load is constant, the recirculation amount of the engine exhaust gas to be recirculated from the exhaust side of the engine to the intake side of the engine is determined based on the state information stored in the state information storing procedure. State information processing procedure,
A state information processing result output procedure in which the exhaust gas is recirculated with the determined recirculation amount;
A state information range recording procedure for storing a state information range when the combustion state of the engine is a target state,
The rotational speed operation means is a fuel supply control valve that adjusts a fuel supply amount to the engine, the state information is an opening of the fuel supply control valve, and the state information range is the fuel supply control valve An opening range of the control valve, and the state information processing unit compares the opening of the fuel supply control valve with the opening range of the fuel supply control valve, and the opening is a lower limit value of the opening range. If smaller, change the reflux amount to a larger value than before the change, and if the opening is larger than the upper limit of the opening range, by changing the reflux amount to a smaller value than before the change, The EGR control method, wherein the reflux amount is changed so that the opening is within the opening range.   6. The EGR control method according to claim 5, wherein the engine load is determined by power consumption.

Images