JP5189012B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine that can use liquid fuel and gaseous fuel.

  Patent Document 1 discloses a control device for an internal combustion engine that can be used by switching between liquid fuel and gaseous fuel. According to this control device, when switching from liquid fuel to gaseous fuel, the throttle valve opening is increased so that the output torque increases by 10% in order to prevent the engine output torque from decreasing by about 10%. On the other hand, when switching from gaseous fuel to liquid fuel, in order to prevent the output torque from increasing by about 10%, the throttle valve opening is reduced so that the output torque is reduced by 10%.

JP 2004-211161 A

  In an internal combustion engine that uses gaseous fuel and liquid fuel, it is necessary to perform control focusing on the following two points. The first point is that when the gaseous fuel is used, it is necessary to increase the air supply amount in order to obtain the same engine output torque as when the liquid fuel is used, and the second point is that the gaseous fuel is used. Is used, the intake pressure on the downstream side of the throttle valve increases compared to when using liquid fuel, so the throttle valve opening required to supply the same amount of air as when using liquid fuel increases. is there. In the above-mentioned Patent Document 1, the first point is considered, but the control method considering the second point is not shown, and there is a possibility that the torque change cannot be eliminated when the fuel to be used is switched.

  In addition, when using gaseous fuel and liquid fuel at the same time, control parameters that are set on the assumption that only gaseous fuel is used or control parameters that are set on the assumption that only liquid fuel is used are used as they are. When applied, the change characteristic of the engine output torque with respect to the depression amount of the accelerator pedal changes, which may give the driver a sense of incongruity. Since patent document 1 does not show the control method in the case of using gaseous fuel and liquid fuel simultaneously, such a malfunction may generate | occur | produce.

  The present invention has been made in consideration of the above-described points, and appropriately controls the amount of air supplied to an internal combustion engine that is switched between liquid fuel and gaseous fuel or used at the same time. An object of the present invention is to provide a control device for an internal combustion engine that can improve the engine.

In order to achieve the above object, according to a first aspect of the present invention, there is provided a control apparatus for an internal combustion engine, comprising: a liquid fuel supply means for supplying liquid fuel; and a gas fuel supply means for supplying gaseous fuel. Air amount control means (3, 4) for controlling the air amount, required output calculation means for calculating the required output (TRQ) of the engine, and the mass ratio (KGAS) of the liquid fuel and gaseous fuel contained in the fuel used The mass ratio calculating means for calculating the required air quantity (QAIRCMD) according to the required output (TRQ) and the mass ratio (KGAS), and the mass ratio (KGAS) according to the required mass ratio (KGAS). Control amount calculation means for calculating a control amount (THCMD) of the air amount control means corresponding to the required air amount (QAIRCMD), the control amount calculation means comprising the fuel used First control value calculating means for calculating a first control value (THGAS) that is a value of the control amount corresponding to the required air amount (QAIRCMD) when only the gaseous fuel is used, and the fuel used is the liquid Second control value calculating means for calculating a second control value (THLIQ) that is a value of the control amount corresponding to the required air amount (QAIRCMD) when only the fuel is used, the first and first The control amount (THCMD) is calculated by interpolating two control values (THGAS, THLIQ) based on the mass ratio (KGAS).

According to a second aspect of the present invention, there is provided a control apparatus for an internal combustion engine comprising a liquid fuel supply means for supplying liquid fuel and a gas fuel supply means for supplying gaseous fuel, wherein a valve provided in an intake pipe of the engine is provided. Air amount control means (3, 4) for controlling the amount of air supplied to the engine by changing the opening (TH), request output calculation means for calculating the required output (TRQ) of the engine, and the request Fuel mass calculating means for calculating the mass of the gaseous fuel (QFGAS) and the mass of the liquid fuel (QFLIQ) according to the output (TRQ), and a first required air amount (QFGAS) based on the mass of the gaseous fuel (QFGAS) QAIRGAS), a required air amount calculating means for calculating a second required air amount (QAIRLIQ) based on the mass (QFLIQ) of the liquid fuel, and the first required air amount ( It is necessary to calculate the first required opening area (ATHGAS) of the intake pipe according to AIRGAS) and to calculate the second required opening area (ATHLIQ) of the intake pipe according to the second required air amount (QAIRLIQ). An opening area calculating means, and a valve opening degree calculating means for converting the sum of the first and second required opening areas (ATHCMD) into the opening degree (THCMD) of the valve are provided.

According to the first aspect of the present invention, the mass ratio between the liquid fuel and the gaseous fuel contained in the used fuel is calculated, and the required air amount is calculated according to the required output and the mass ratio. Then, a first control value corresponding to the required air amount when the used fuel is only the gaseous fuel and a second control value corresponding to the required air amount when the used fuel is only the liquid fuel are calculated. By interpolating the first and second control values based on the mass ratio, the control amount of the air amount control means is calculated. Therefore, the control amount for supplying the required air amount can be accurately calculated, and the control accuracy of the air supply amount can be improved by controlling the air amount control means using the calculated control amount. it can.

According to the second aspect of the present invention, the mass of the gaseous fuel and the mass of the liquid fuel are calculated according to the engine required output, the first required air amount is calculated based on the mass of the gaseous fuel, and the liquid fuel Based on the mass of the second required air amount is calculated. Then, the first required opening area of the intake pipe is calculated according to the first required air amount, the second required opening area is calculated according to the second required air amount, and the sum of the first and second required opening areas is calculated. Is converted into the opening of the valve in the intake pipe. Therefore, the control accuracy of the air supply amount can be improved by controlling the actual valve opening so as to coincide with the calculated valve opening.

It is a figure which shows the structure of the internal combustion engine and its control apparatus concerning one Embodiment of this invention. It is a flowchart (1st Embodiment) of the process which calculates required air quantity (QAIRCMD). It is a flowchart (1st Embodiment) of the process which calculates the target opening degree (THCMD) of a throttle valve. It is a figure which shows the table referred by the process of FIG. It is a flowchart (2nd Embodiment) of the process which calculates required air quantity (QAIRCMD). It is a flowchart (2nd Embodiment) of the process which calculates the target opening degree (THCMD) of a throttle valve. It is a flowchart of the modification of 2nd Embodiment. It is a figure which shows the table referred by the process of FIG.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram showing a configuration of an internal combustion engine and a control device thereof according to an embodiment of the present invention. An internal combustion engine (hereinafter referred to as an “engine”) 1 is a four-cylinder engine that can be used by switching between compressed natural gas (Compressed Natural Gas, hereinafter referred to as “CNG”) and gasoline, which is a liquid fuel, or simultaneously. It is an engine. The engine 1 includes an intake valve, an exhaust valve, and a cam that drives the intake valve, and a cam phase variable mechanism that continuously changes an operation phase of the cam that drives the intake valve based on the crankshaft rotation angle. A variable valve operating characteristic mechanism 40 is provided. The operating phase of the cam that drives the intake valve is changed by the valve operating characteristic variable mechanism 40, and the operating phase angle VTC of the intake valve is changed. A specific configuration of the valve operation characteristic variable mechanism 40 is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-227013.

  A throttle valve 3 is provided in the intake pipe 2 of the engine 1. An actuator 4 that drives the throttle valve 3 is connected to the throttle valve 3, and the actuator 4 is connected to an electronic control unit (hereinafter referred to as “ECU”) 5. The ECU 5 controls the opening degree TH of the throttle valve 3 via the actuator 4. A throttle valve opening sensor 22 for detecting the throttle valve opening TH is connected to the throttle valve 3, and a detection signal is supplied to the ECU 5.

  The fuel supply system for supplying fuel to the engine 1 includes a liquid fuel supply device including a liquid fuel injection valve 6, a liquid fuel passage 8, and a liquid fuel tank 9, a gas fuel injection valve 7, a gas fuel passage 10, and a gas fuel. And a gaseous fuel supply device including a tank 11. The liquid fuel supply device supplies gasoline to the engine 1, and the gaseous fuel supply device supplies CNG to the engine 1.

  The liquid fuel injection valve 6 is provided for each cylinder in the middle of the intake pipe 2 and slightly upstream of an intake valve (not shown) between the engine 1 and the throttle valve 3. The liquid fuel injection valve 6 is connected to a liquid fuel tank 9 through a liquid fuel passage 8. A gaseous fuel injection valve 7 is provided for each cylinder in the vicinity of the liquid fuel injection valve 6. The gaseous fuel injection valve 7 is connected to a gaseous fuel tank 11 through a gaseous fuel passage 10.

  The liquid fuel injection valve 6 and the gaseous fuel injection valve 7 are electrically connected to the ECU 5, and the valve opening time and the valve opening timing are controlled by signals from the ECU 5. An intake pressure sensor 23 for detecting the intake pressure PBA and an intake air temperature sensor 24 for detecting the intake air temperature TA are mounted on the downstream side of the throttle valve 3 of the intake pipe 2. Detection signals from these sensors are supplied to the ECU 5.

  The engine 1 is provided with a crank angle position sensor 25 that detects a rotation angle of a crankshaft (not shown) of the engine 1, and a signal corresponding to the rotation angle of the crankshaft is supplied to the ECU 5. The crank angle position sensor 25 is a cylinder discrimination sensor that outputs a pulse (hereinafter referred to as “CYL pulse”) at a predetermined crank angle position of a specific cylinder of the engine 1, and relates to a top dead center (TDC) at the start of the intake stroke of each cylinder. A TDC sensor that outputs a TDC pulse at a crank angle position before a predetermined crank angle (every 180 degrees of crank angle in a four-cylinder engine) and one pulse (hereinafter referred to as “CRK”) with a constant crank angle cycle shorter than the TDC pulse (for example, a cycle of 6 °). The CYL pulse, the TDC pulse, and the CRK pulse are supplied to the ECU 5. These pulses are used for various timing controls such as fuel injection timing and ignition timing, and detection of engine speed (engine speed) NE.

  An engine cooling water temperature sensor 26 for detecting the engine cooling water temperature TW is mounted on the main body of the engine 1, and the detection signal is supplied to the ECU 5. The exhaust pipe 12 of the engine 1 is provided with an oxygen concentration sensor (hereinafter referred to as “LAF sensor”) 27 for detecting the oxygen concentration in the exhaust, and the detection signal of the LAF sensor 27 is supplied to the ECU 5.

  Connected to the ECU 5 are an accelerator sensor 28 for detecting an accelerator pedal depression amount (hereinafter referred to as “accelerator pedal operation amount”) AP of a vehicle driven by the engine 1 and an atmospheric pressure sensor 29 for detecting an atmospheric pressure PA. The detection signals from these sensors are supplied to the ECU 5.

  The ECU 5 shapes input signal waveforms from various sensors, corrects the voltage level to a predetermined level, converts an analog signal value into a digital signal value, etc., and a central processing unit (hereinafter referred to as “CPU”). An output circuit for supplying a drive signal to a storage circuit for storing various calculation programs executed by the CPU and calculation results, the fuel injection valves 6 and 7, the actuator 4, and an ignition plug (not shown) of each cylinder. Consists of

  The ECU 5 performs fuel supply control, ignition timing control, intake valve operating phase angle VTC control, and the like in accordance with the engine operating state such as the accelerator pedal operation amount AP and the engine speed NE. Further, the ECU 5 calculates a required air amount QAIRCMD that is the amount of air to be supplied to the engine 1 according to the engine operating state, and calculates and detects the target opening THCMD of the throttle valve 3 according to the required air amount QAIRCMD. The actuator 4 is controlled so that the throttle valve opening TH to be made coincides with the target opening THCMD.

FIG. 2 is a flowchart of a process for calculating the required air amount QAIRCMD [g / sec] according to the required torque TRQ of the engine 1.
In step S11, the required torque TRQ is calculated according to the accelerator pedal operation amount AP and the like. The required torque TRQ is basically calculated so as to be substantially proportional to the accelerator pedal operation amount AP. In step S12, a gasoline required air amount QAIRLIQ corresponding to the case where gasoline is used according to the required torque TRQ is calculated.

  In step S13, it is determined whether or not the gaseous fuel flag FGAS is “1”. The gaseous fuel flag FGAS is set to “1” when CNG is used. When the gaseous fuel flag FGAS is “0” and gasoline is used, the required air amount QAIRCMD is set to the gasoline required air amount QAIRLIQ calculated in step S12 (step S15).

On the other hand, when FGAS = 1 and CNG is used, the required air amount QAIRCMD is calculated by the following equation (1) (step S14). KCNG in equation (1) is a CNG correction coefficient, and the required air amount when using CNG needs to be increased from the required air amount QAIRLIQ, which is the required air amount when using gasoline. Is done. The CNG correction coefficient KCNG is set so that the calorific value when the air-fuel ratio is the stoichiometric air-fuel ratio is the same as the calorific value when using gasoline, for example, “1.1”.
QAIRCMD = QAIRLIQ × KCNG (1)

  FIG. 3 is a flowchart of processing for calculating the target opening THCMD of the throttle valve 3 in accordance with the required air amount QAIRCMD.

In step S21, the required air amount QAIRCMD, the atmospheric pressure PA, and the intake air temperature TA are applied to the following formula (2) to convert the required air amount QAIRCMD into the required air volume flow rate VAIRCMD [L / min]. R in the formula (2) is a gas constant (= 0.082), and M is an average molecular weight (= 29) of molecules constituting the air.

  In step S22, it is determined whether or not the gaseous fuel flag FGAS is “1”. If the answer is negative (NO), the THLIQ table indicated by a broken line in FIG. 4 is shown in accordance with the required air volume flow rate VAIRCMD. A search is made to calculate the gasoline target opening THLIQ [deg] (step S25). In step S26, the target opening THCMD is set to the gasoline target opening THLIQ.

  If the answer to step S22 is affirmative (YES), that is, if CNG is used, the THGAS table shown by a solid line in FIG. 4 is searched according to the required air volume flow rate VAIRCMD, and the CNG target opening THGAS [deg] is calculated. (Step S23). In step S24, the target opening degree THCMD is set to the CNG target opening degree THGAS.

  When CNG is used, it is shown in FIG. 4 in consideration that the intake pressure PBA becomes higher than that when gasoline is used when the amount of fuel necessary to obtain the same calorific value (output torque) as gasoline is injected. The table is set so that the CNG target opening THGAS corresponding to the same required volume air flow rate VAIRCMD is larger than the gasoline target opening THLIQ. The table shown in FIG. 4 is provided in correspondence with a plurality of predetermined engine speeds and predetermined intake valve operating phase angles, and is used according to the engine speed NE and the intake valve operating phase angle VTC. A table is appropriately selected and necessary interpolation calculation is performed to calculate the gasoline target opening THLIQ or the CNG target opening THGAS. This is because even if the throttle valve opening is the same, the amount of air taken into the cylinder differs depending on the engine speed NE and the intake valve operating phase angle VTC. The table in FIG. 4 is set in advance based on experiments and the like, and stored in the storage circuit of the ECU 5.

  As described above, in the present embodiment, the required air amount QAIRCMD is calculated according to whether the fuel used is gasoline or CNG and the required torque TRQ, and the throttle corresponding to the required air amount QAIRCMD according to the fuel used. A target opening THCMD of the valve 3 is calculated. Therefore, the throttle valve opening THCMD for supplying the required air amount QAIRCMD can be accurately calculated, and the actuator 4 is controlled so that the detected throttle valve opening TH matches the target opening THCMD. Regardless of the fuel used, the control accuracy of the air supply amount of the engine 1 can be improved.

  In the present embodiment, the throttle valve 3 and the actuator 4 correspond to air amount control means, and the ECU 5 constitutes required output calculation means, determination means, required air amount calculation means, and control amount calculation means. Specifically, step S11 in FIG. 2 corresponds to the required output calculation means, step S13 in FIG. 2 and step S22 in FIG. 3 correspond to the determination means, and steps S12, S14, and S15 in FIG. 3 corresponds to the amount calculation means, and steps S21 and S22 to S26 in FIG. 3 correspond to the control amount calculation means.

[Second Embodiment]
This embodiment uses liquid fuel and gaseous fuel at the same time according to the mass ratio KGAS, and is the same as the first embodiment except for the points described below. In this embodiment, the mass ratio KGAS is defined as a parameter indicating the mass ratio of CNG in the fuel used, with “0” when only gasoline is used and “1” when only CNG is used.

FIG. 5 is a flowchart of the required air amount calculation process in the present embodiment.
Steps S31 and S32 are the same as steps S11 and S12 of FIG. 2, respectively. In step S33, CNG required air amount QAIRGAS is calculated by the following equation (11).
QAIRGAS = QAIRLIQ × KCNG (11)

  In step S34, a mass ratio KGAS is calculated. When the fuel used is switched from gasoline to CNG or vice versa, the mass ratio KGAS changes between “0” and “1” by a predetermined amount of transition every predetermined time, that is, from “0” to “1”. It is set to gradually change with time. The mass ratio KGAS may be calculated according to engine operating parameters such as the engine coolant temperature TW, and the mass ratio KGAS may be calculated according to the remaining amount of gasoline and the remaining amount of CNG. good. Alternatively, the mass ratio KGAS may be a constant value.

In step S35, the required air amount QAIRLIQ, the CNG required air amount QAIRGAS, and the mass ratio KGAS are applied to the following equation (12) to calculate the required air amount QAIRCMD.
QAIRCMD = KGAS × QAIRGAS
+ (1-KGAS) × QAIRLIQ (12)

FIG. 6 is a flowchart of the target opening degree calculation process in the present embodiment.
In step S41, the required air amount QAIRCMD is converted into the required volume flow rate VAIRCMD, as in step S21 of FIG. In step S42, the THGAS table in FIG. 4 is searched according to the required volume flow rate VAIRCMD, and the CNG target opening THGAS is calculated. In step S43, the THLIQ table of FIG. 4 is searched to calculate the gasoline target opening THLIQ.

In step S44, the target opening degree THCMD is calculated by applying the gasoline target opening degree THLIQ, the CNG target opening degree THGAS, and the mass ratio KGAS to the following equation (13).
THCMD = KGAS × THGAS
+ (1-KGAS) × THLIQ (13)

  According to the present embodiment, the mass ratio KGAS between gasoline and CNG contained in the used fuel is calculated, and the required air amount QAIRCMD is calculated according to the required torque TRQ and the mass ratio KGAS. Then, a gasoline target opening THLIQ corresponding to the required air amount when the fuel used is only gasoline and a CNG target opening THGAS corresponding to the required air amount when the fuel used is only CNG are calculated. The target opening THCMD is calculated by interpolating the target opening THLIQ and the CNG target opening THGAS based on the mass ratio KGAS. Therefore, the target opening THCMD for supplying the required air amount QAIRCMD is accurately calculated, and the actuator 4 is controlled so that the detected throttle valve opening TH coincides with the target opening THCMD. Can be used simultaneously, the control accuracy of the air supply amount of the engine 1 can be improved.

  In this embodiment, the liquid fuel supply device and the gaseous fuel supply device correspond to the liquid fuel supply device and the gaseous fuel supply device, respectively, the throttle valve 3 and the actuator 4 correspond to the air amount control device, and the ECU 5 outputs the required output. A calculation unit, a mass ratio calculation unit, a required air amount calculation unit, a first control value calculation unit, a second control value calculation unit, and a control amount calculation unit are configured. Specifically, step S31 in FIG. 5 corresponds to the required output calculation means, step S34 corresponds to the mass ratio calculation means, and steps S32, S33, and S35 correspond to the required air amount calculation means. Further, steps S41 and S42 in FIG. 6 correspond to first control value calculation means, steps S41 and S43 correspond to second control value calculation means, and steps S41 to S44 correspond to control amount calculation means.

  The present invention is not limited to the embodiment described above, and various modifications can be made. For example, the processing of FIGS. 5 and 6 in the second embodiment may be replaced with the processing of FIG.

  Steps S51 and S52 in FIG. 7 are the same processes as steps S31 and S34 in FIG. 5, respectively. In step S53, CNG mass QFGAS [g / sec] and gasoline mass QFLIQ [g / sec] necessary for obtaining the required torque TRQ are calculated according to the required torque TRQ and the mass ratio KGAS.

  In step S54, CNG required air amount QAIRGAS is calculated by multiplying CNG mass QFGAS by CNG air-fuel ratio AFGAS. In step S55, gasoline required air amount QAIRLIQ is calculated by multiplying gasoline mass QFLIQ by gasoline air-fuel ratio AFLIQ. calculate.

  In step S56, the CNG required air amount QAIRGAS and the gasoline required air amount QAIRLIQ are converted into a CNG required volume air flow rate VAIRGAS and a gasoline required volume air flow rate VAIRLIQ, respectively.

  In step S57, an ATHGAS table indicated by a solid line in FIG. 8A is searched according to the CNG required volume air flow rate VAIRGAS, and the CNG required opening area ATHGAS is calculated. In step S58, an ATHLIQ table indicated by a broken line in FIG. 8A is searched according to the gasoline required volume air flow rate VAIRLIQ, and a gasoline required opening area ATHLIQ is calculated. In steps S57 and S58, instead of using the table in FIG. 8A, the CNG required opening area ATHGAS and the gasoline required opening area ATHLIQ may be calculated using mathematical expressions modeling the throttle valve 3, respectively. good.

  As in the table shown in FIG. 4, a plurality of tables shown in FIG. 8A are provided corresponding to a plurality of predetermined engine speeds and predetermined intake valve operation phase angles. A table to be used is appropriately selected according to the operating phase angle VTC, and necessary interpolation calculation is performed to calculate the gasoline required opening ATHLIQ or CNG required opening area ATHGAS.

In step S59, the required opening area ATHCMD of the throttle valve 3 is calculated by the following equation (14).
ATHCMD = ATHGAS + ATHLIQ (14)
In step S60, the THCMD table shown in FIG. 8B is searched according to the required opening area ATHCMD to calculate the target opening THCMD.

  By the process of FIG. 7, an amount of air suitable for the mass ratio KGAS of CNG and gasoline in the fuel used can be supplied.

  In the process of FIG. 7, step S51 corresponds to the required output calculation means, steps S52 and S53 correspond to the fuel mass calculation means, steps S54 and S55 correspond to the required air amount calculation means, and steps S56 to S58 are required. It corresponds to the opening area calculating means, and steps S59 and S60 correspond to the valve opening degree calculating means.

  Moreover, as liquid fuel, not only gasoline but alcohol can also be applied, and as gaseous fuel, hydrocarbon gas other than CNG is also applicable.

  The present invention can also be applied to control of a marine vessel propulsion engine such as an outboard motor having a crankshaft as a vertical direction.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Intake pipe 3 Throttle valve (air quantity control means)
4 Actuator (Air volume control means)
5 Electronic control unit (determination means, required air amount calculation means, control amount calculation means, required output calculation means, mass ratio calculation means, first control value calculation means, second control value calculation means, fuel mass calculation means, required opening (Area calculation means, valve opening calculation means)
6 Liquid fuel injection valve (liquid fuel supply means)
7 Gaseous fuel injection valve (gaseous fuel supply means)
8 Liquid fuel passage (liquid fuel supply means)
9 Liquid fuel tank (liquid fuel supply means)
10 Gaseous fuel passage (gaseous fuel supply means)
11 Gaseous fuel tank (gaseous fuel supply means)

Claims (2)

In a control device for an internal combustion engine, comprising: a liquid fuel supply means for supplying liquid fuel; and a gaseous fuel supply means for supplying gaseous fuel.
An air amount control means for controlling the amount of air supplied to the engine;
Demand output calculation means for calculating the demand output of the engine;
A mass ratio calculating means for calculating a mass ratio of the liquid fuel and the gaseous fuel contained in the fuel used;
A required air amount calculating means for calculating a required air amount according to the required output and mass ratio;
Control amount calculation means for calculating a control amount of the air amount control means corresponding to the required air amount according to the mass ratio,
The control amount calculating means includes
First control value calculating means for calculating a first control value that is a value of the control amount corresponding to the required air amount when the fuel used is only the gaseous fuel;
Second control value calculating means for calculating a second control value that is a value of the control amount corresponding to the required air amount when the fuel used is only the liquid fuel;
A control device for an internal combustion engine, wherein the control amount is calculated by interpolating the first and second control values based on the mass ratio. In a control device for an internal combustion engine, comprising: a liquid fuel supply means for supplying liquid fuel; and a gaseous fuel supply means for supplying gaseous fuel.
An air amount control means for controlling the amount of air supplied to the engine by changing the opening of a valve provided in the intake pipe of the engine;
Demand output calculation means for calculating the demand output of the engine;
Fuel mass calculating means for calculating the mass of the gaseous fuel and the mass of the liquid fuel according to the required output;
A required air amount calculating means for calculating a first required air amount based on the mass of the gaseous fuel and calculating a second required air amount based on the mass of the liquid fuel;
A required opening area calculating means for calculating a first required opening area of the intake pipe according to the first required air quantity and calculating a second required opening area of the intake pipe according to the second required air quantity; ,
A control device for an internal combustion engine, comprising: a valve opening degree calculation unit that converts a sum of the first and second required opening areas into an opening degree of the valve.

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