JP2008088864A - Control device for dual-fuel engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a dual-fuel engine operable by changeover between liquid fuel and gaseous fuel, operable by selecting gaseous fuel even in time other than a catalyst unactivated time, and appropriately ensuring gaseous fuel to be used in the catalyst unactivated time to improve exhaust emission performance. <P>SOLUTION: This control device is configured that gaseous fuel is selected as fuel to be used in the catalyst inactivation time unless a gaseous fuel (hydrogen) residual amount is not a first predetermined amount or less (running-out of fuel), and after catalyst activation, a driver can select fuel by switch operation. For keeping gaseous fuel to be used in the catalyst unactivated time, liquid fuel (gasoline) is selected as fuel to be used while prohibiting fuel selection by the switch operation when the gaseous fuel residual amount is a second predetermined amount or less greater than the first predetermined amount. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control apparatus for a dual fuel engine that can be operated by switching a fuel to be used between liquid fuel (gasoline, light oil, etc.) and gas fuel (hydrogen, CNG, etc.).

It is a dual fuel engine that switches between gasoline, which is liquid fuel, and CNG (compressed natural gas), which is gas fuel, and always uses gas fuel until the catalyst is activated at the time of cold start. What has improved emission performance is conventionally known (for example, refer to Patent Document 1).
JP 2000-213394 A

  By the way, even though the conventional dual fuel engine is used by switching between liquid fuel and gas fuel, the gas fuel is used only until the catalyst is activated at the time of cold start. It uses gaseous fuel only to improve emission performance.

  On the other hand, it is a dual fuel engine that can be used by switching between liquid fuel and gas fuel, and when the driver wants to run using gas fuel in a clean-oriented manner, the fuel can be freely switched by operating the switch. There is a demand for switching the fuel to be used by passengers other than when the catalyst is inactive.

  Therefore, for example, a switch for fuel switching is provided on the instrument panel (instrument panel for short) in front of the driver's seat of the vehicle so that the driver can select the fuel to be used by operating the switch. It is considered to always run with gaseous fuel if the fuel is selected.

  However, if the fuel can be switched indefinitely by the occupant's will, liquid fuel may be used when the catalyst is not activated at the time of cold start. In such a case, the effect of improving the emission performance by using gaseous fuel Cannot be obtained.

  In addition, since the fuel can be switched indefinitely, if there is an increase in the amount of gaseous fuel used for purposes other than catalyst activation, the remaining amount of gaseous fuel will be insufficient, making it difficult to start using hydrogen when the catalyst is inactive. There is a risk that the original purpose of improving emission performance during activation may not be achieved. Therefore, there is a demand for securing a gaseous fuel to be used when the catalyst is deactivated. However, the conventional technology cannot meet such a demand. In the prior art, no consideration is given to securing the amount of gaseous fuel for cold start.

  Therefore, the present invention can select and operate a gaseous fuel other than when the catalyst is inactive, and can appropriately secure the gaseous fuel for use when the catalyst is inactive to improve the exhaust emission performance. An object of the present invention is to provide a dual fuel engine control device that can be operated by switching between liquid fuel and gaseous fuel.

  The present invention relates to a dual fuel engine control device capable of switching between liquid fuel (gasoline, light oil, etc.) and gaseous fuel (hydrogen, CNG, ie, natural gas, etc.) as a fuel to be used. Means for detecting the value to be detected and determining the remaining amount of gaseous fuel, means for detecting the value related to the activation state of the catalyst for exhaust purification and determining the activation state of the catalyst, and the catalyst is not activated Sometimes the first fuel selection means that uses gaseous fuel as the gaseous fuel, and when the remaining amount of gaseous fuel is less than or equal to the first predetermined amount, the first fuel selection means prohibits switching to the gaseous fuel and uses the used fuel as the liquid fuel. And a third fuel that can select the fuel to be used when a predetermined condition (for example, established by an occupant operating a predetermined switch) is satisfied after the catalyst is activated. A selection means; Fourth fuel selection means for selecting the liquid fuel as the used fuel while prohibiting the switching of the used fuel by the third fuel selecting means when the remaining amount of the body fuel is equal to or less than the second predetermined amount larger than the first predetermined amount. It is characterized by that.

  In this case, the gaseous fuel is selected by the first fuel selection means until the catalyst is activated at the time of starting the engine, and the engine is started with the gaseous fuel. Therefore, exhaust emission performance when the catalyst is inactive is improved.

  Further, even when the catalyst is not activated, when the remaining amount of the gaseous fuel is equal to or less than the first predetermined amount, the second fuel selection means forcibly switches to the liquid fuel. This prevents the engine from being unable to continue operating due to the lack of gaseous fuel.

  In addition, after the catalyst is activated, when a predetermined condition such as a switch operation by the driver is established, the fuel to be used can be selected by the third fuel selection unit by operating the switch, for example. For example, when the driver presses a fuel switching switch, the used fuel can be freely switched from a gaseous fuel to a liquid fuel, or from a liquid fuel to a gaseous fuel.

  However, the switching of the fuel to be used by the third fuel selection means is prohibited by the prohibiting means when the remaining amount of the gaseous fuel is equal to or less than the second predetermined amount larger than the first predetermined amount. That is, when the remaining amount of the gaseous fuel is sufficiently large (greater than the second predetermined amount), both the gaseous fuel can be used when the catalyst is inactive and the gaseous fuel can be used by operating the driver's switch. However, when the remaining amount of gaseous fuel becomes low (second predetermined amount or less), the pressure of the gaseous fuel that can be injected from the injector disappears, so that the driver does not run out of fuel. Use of gaseous fuel by switch operation etc. is prohibited, and liquid fuel is selected as fuel used. Thereby, the gaseous fuel to be used is ensured until the catalyst is activated.

  As described above, the dual fuel engine control device of the present invention can improve the exhaust emission performance by using the gaseous fuel when the catalyst is inactive. It is possible to appropriately respond to the request to be able to switch between.

  According to the dual fuel engine control device of the present invention, in the above-described configuration, the second predetermined amount is increased when the outside air temperature is equal to or lower than the means for detecting the outside air temperature by detecting a value related to the outside air temperature. Means may be provided.

  For example, when the outside air temperature is low, such as in winter, the catalyst tends to fall below the activation temperature and does not warm easily, so that the amount of gaseous fuel required for catalyst activation at the next engine start increases. Therefore, when the outside air temperature is low, the second predetermined amount is increased in this way. Accordingly, it is possible to appropriately secure a gaseous fuel to be used when the catalyst is inactive.

  The dual fuel engine control device according to the present invention is related to the consumption amount of gaseous fuel from when the remaining amount of gaseous fuel reaches a level that requires refueling until the gaseous fuel is replenished. Means for detecting the value and determining the consumption amount of the gaseous fuel after the replenishment request, and means for increasing the second predetermined amount as the consumption amount increases can be provided.

  Detecting that the remaining amount of gaseous fuel has reached a level that requires refueling, for example, by detecting that the remaining amount of gaseous fuel has fallen below the second predetermined amount, for example, and turning on a fuel out lamp Even if fuel gas replenishment is encouraged, some drivers may not easily replenish gas fuel, and the remaining amount of gas fuel is decreasing, making it impossible to use gas fuel when starting the engine. is there. Therefore, for example, how much gaseous fuel is reduced from when the gas fuel out-of-fuel lamp is lit until the gaseous fuel is replenished (how much gaseous fuel is used for operation when the catalyst is inactive). The large amount of consumption means that it is difficult to replenish gaseous fuel. In such a case, the second predetermined amount is increased in this way, and the gaseous fuel is used when the catalyst is not active. Is banned early, and refueling is encouraged early. Thereby, the gaseous fuel for using at the time of catalyst inactive can be ensured appropriately.

  As described above, according to the present invention, it is possible to improve the exhaust emission performance by using gaseous fuel when the catalyst is inactive, and to change the fuel to be used by operating the switch other than when the catalyst is inactive. It can respond appropriately to the request to do.

  Further, in particular, by providing means for detecting a value related to the outside air temperature to determine the outside air temperature, and means for increasing the second predetermined amount when the outside air temperature is equal to or lower than the predetermined temperature, the outside air temperature is reduced. Even when the temperature is low, it is possible to appropriately secure gaseous fuel for use when the catalyst is inactive.

  In particular, the consumption of gaseous fuel after a replenishment request is detected by detecting a value related to the consumption of gaseous fuel from when the remaining amount of gaseous fuel reaches a level that requires refueling until the gaseous fuel is replenished. By providing a means for determining the amount and a means for increasing the second predetermined amount as the consumption amount increases, it is predicted that the gaseous fuel will not be replenished easily, and the gaseous fuel other than when the catalyst is inactive Can be prohibited early and replenishment can be urged early, thereby ensuring adequate gas fuel for use when the catalyst is inactive.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1-7 has shown an example of embodiment of this invention. 1 is an overall view of a drive system for a vehicle equipped with a dual fuel engine of this embodiment, FIG. 2 is a control block diagram of the dual fuel engine, FIG. 3 is an explanatory diagram of a basic concept of fuel switching control of the dual fuel engine, FIG. FIG. 5 is a flowchart showing a main routine of dual fuel engine fuel switching control. FIG. 6 is a flowchart showing an example of a fuel switching control subroutine of the dual fuel engine. 7 is a flowchart showing another example of the fuel switching control subroutine of the dual fuel engine.

  In this embodiment, a dual fuel engine that can be operated by switching between gasoline (liquid fuel) and hydrogen (gaseous fuel) is not used to drive the vehicle by directly transmitting the driving force of the engine to the axle. It is mounted on a vehicle of a hybrid system (referred to as a series hybrid) that drives the engine and moves the engine to generate electric power to be supplied to the motor.

  The vehicle drive system is as shown in FIG. 1, and includes an engine 1, a gasoline fuel tank 2 and a hydrogen fuel tank 3, a gasoline supply passage 4 for supplying gasoline from the gasoline fuel tank 2 to the engine 1, and a hydrogen fuel tank 3. A hydrogen supply passage 5 for supplying hydrogen to the engine 1, a generator (generator) 7 driven by an output shaft 6 of the engine 1, and a motor (electric motor) 10 for driving an axle 9 via a differential (differential) 8; A battery (high voltage battery) 11 that stores electric power for driving the motor, an AC-DC converter 12 that converts alternating current into direct current, and an AC-DC that converts alternating current generated by the generator 7 into direct current A current path 13 flowing to the converter 12, a DC-AC converter 14 for converting a direct current into an alternating current, and an AC-DC converter Current path 15 for flowing the direct current from the battery 12 to the battery 11, and the current path for flowing the direct current from the AC-DC converter 12 and the direct current from the battery 11 to the DC-AC converter 14 separately from the current path 15. 16 and a current path 17 for supplying an alternating current from the DC-AC converter 14 to the motor 10.

  Although not shown, a DC path from the AC-DC converter 12 to the battery 11 has a current path 15 that is closer to the battery 11 than a branch point of the current path 16 to the DC-AC converter 14. A battery changeover switch is provided for switching between a position where the direct current from the battery is supplied to the high voltage battery 11 side and a position where the direct current is supplied to the motor 10 via the DC-AC converter 14.

And the driving | running form of this series hybrid vehicle is as follows.
The engine 1 does not always move. When the vehicle is started or when the torque is low, a large driving force is not necessary. Therefore, the engine 1 is not moved and the electric power of the high voltage battery 11 is DC- The vehicle is driven by being supplied to the motor 10 via the AC converter 16.

  On the other hand, when the torque increases and becomes a medium torque state, the amount of electricity stored in the battery 11 decreases as the electric power is taken out from the battery 11. In this case, the engine 1 is operated, and the engine 1 generates the generator. 7 is driven, and the electric power generated by the generator 7 is supplied to the motor 10 to drive the vehicle.

  When the torque is further increased and the torque becomes high, the amount of power generated by the engine 1 cannot be satisfied. Therefore, both the power generated by the generator 7 by driving the engine 1 and the power of the battery 11 are motorized. 10 to drive the vehicle.

  Also, when the battery 11 has a small amount of charge and needs to be charged, then the engine 1 is not running, for example, running at a low torque, and the charge amount of the battery 11 is steadily decreasing. In the case of such a situation, the engine 1 is started and the battery 11 is charged.

  In addition, when the battery 11 has a small amount of charge and needs to be charged, the engine 1 is already running, for example, the power generated by the generator 7 by driving the engine 1 with high torque. When both the electric power of the battery 11 is supplied to the motor 10 and the storage amount of the battery 11 is reduced, the battery 11 waits for a middle torque state and exceeds the electric power required by the motor 10. The engine 1 is driven so as to obtain a power generation amount, the power generation amount of the generator 7 is kept as high as possible, the surplus power is supplied to the battery 11, and the battery 11 is charged.

  In this series hybrid system, as shown in FIG. 2, the engine 1 rotates along a pair of rotor housings 101 and 102 and an inner peripheral surface thereof supported by an output shaft 6 (eccentric shaft) 2. A two-rotor rotary engine including two rotors 103 and 104 (a pair of rotor housings 101 and 102 is schematically shown in a left and right direction in FIG. 2), and is common to the upstream side of the intake passage 105 A throttle valve 106 is provided in the passage portion, and a throttle valve actuator 107 that drives the throttle valve 106 is disposed. Further, gasoline fuel injection valves 108 and 109 for performing port injection are provided in two independent passage portions branched downstream of the intake passage 105, and fuel is supplied to the rotor housings 101 and 102 in the combustion chamber. Fuel injection valves 110 and 111 for hydrogen are installed so as to inject. Further, two spark plugs 112, 113; 114, 115 are installed in each rotor housing 101, 102. The throttle valve actuator 107, the fuel injection valves 108 and 109 for gasoline, the fuel injection valves 110 and 111 for hydrogen, and the spark plugs 112 and 113; 114 and 115 are controlled by a computer (PCM) 120. A control system is configured.

  In this computer (PCM) 120, various signals for throttle control, air-fuel ratio control, ignition timing control, etc. are input in the same manner as in a conventionally known engine, in addition to a battery current / voltage sensor 121 and The pressure sensor 122 of the hydrogen fuel tank 3, the fuel sensor 123 of the gasoline fuel tank 2, the fuel changeover switch 124 provided in the instrument panel (instrument panel), the outside air temperature sensor 125, and the catalyst temperature sensor 126, respectively. A detection signal is input. The computer (PCM) 120 controls the power supplied to the motor 10 by controlling the AC-DC converter 12 and the DC-AC converter 14 based on the input signals, controls the battery switching switch, and switches the fuel. Control the valve.

  The battery current / voltage sensor 121 is attached to the battery 11. The battery current / voltage sensor 121 obtains the electric power that enters the battery 11 and the electric power that leaves the battery 11 from the current and voltage, and detects the amount of electricity stored in the battery 11. The catalyst temperature sensor 126 is attached to the catalyst and directly detects the catalyst temperature. However, the catalyst temperature may be estimated from the exhaust temperature.

  This engine 1 is operated by switching the fuel to be used between gasoline and hydrogen. The engine 1 automatically uses hydrogen until the catalyst is activated at the time of starting the engine, and after the catalyst is activated, the driver If gasoline is selected, switch to gasoline, and if hydrogen is selected, use hydrogen as it is. Also, even when the catalyst is not activated, if hydrogen is out of fuel, the engine is started with gasoline. Also, when hydrogen is used and hydrogen runs out of fuel, it is automatically switched to gasoline, and when gasoline is used and gasoline runs out of fuel, it is automatically switched to hydrogen. In the engine 1, after the catalyst is activated, the driver can switch the fuel by operating the fuel switch 124 of the instrument panel. Which fuel is currently being used is indicated on the display part with a speedometer.

  Further, in the engine 1, as shown in FIG. 3, the use of hydrogen is prohibited when the remaining amount of hydrogen is in a state of running out of fuel where the hydrogen cannot be injected from the injector (first predetermined amount or less). Switch fuel to gasoline.

  In addition, for the purpose of securing the hydrogen to be used until the catalyst is activated, the remaining amount of hydrogen is reduced to a state close to the out-of-fuel state (first predetermined amount) (second predetermined amount or less). When this happens, the driver's fuel changeover switch 124 prohibits the change of the fuel used. The fuel used is gasoline except when the catalyst is inactive. Then, the fuel shortage lamp is turned on to prompt the driver to supply hydrogen.

  When the remaining amount of hydrogen is larger (greater than the second predetermined amount), both the use of hydrogen when the catalyst is inactive and the use of hydrogen by the driver's switch operation are possible.

  In addition, when the outside air temperature is low, the catalyst is likely to cool, the catalyst is likely to be below the activation temperature, does not warm up easily, and the consumption of hydrogen is expected to increase. Therefore, in order to secure as much hydrogen as possible Furthermore, as shown in FIG. 4, the region (B) in which the use of hydrogen is permitted only when the catalyst is inactive is expanded to the side where the remaining amount of hydrogen is large (the second predetermined amount is increased). Thereby, even when the outside air temperature is low, it is possible to appropriately secure hydrogen for use when the catalyst is inactive.

In addition, when the remaining amount of hydrogen is low and the fuel out lamp is lit, the average value of the amount of hydrogen used until hydrogen is replenished is stored.
The threshold value (second predetermined amount) for turning off the fuel and turning off the fuel lamp is increased. Even if you urge the refueling lamp to turn on the hydrogen supply, depending on the driver, it may not be easy to replenish the hydrogen, so how much time from when the hydrogen out-of-fuel lamp lights up until the hydrogen is replenished Seeing whether hydrogen is decreasing (how much gaseous fuel is used for operation when the catalyst is inactive), memorize the average value, and if the average value is high, it means that the hydrogen out-of-fuel lamp In such a case, switching with the switch is prohibited and the threshold value (second predetermined amount) for turning on the fuel shortage lamp is increased to prevent the catalyst from being replenished. The use of hydrogen other than when it is not activated is prohibited early, and replenishment of gaseous fuel is encouraged early so that hydrogen can be secured for use when the catalyst is inactive.

  Next, the fuel switching control procedure of the engine 1 will be described with reference to the flowcharts of FIGS.

The flowchart of FIG. 5 shows the main routine of the fuel switching control, which starts simultaneously with the engine start command.
In step S1, it is determined whether or not there is an engine operation request. Immediately after the start, there is an engine operation request, and the determination is “Yes”. However, after returning several times, there is a case where the engine is in a low torque state and there is no engine operation request, and this determination is “No”. In that case, the engine is stopped in step S2, and the process returns.

  If the determination in step S1 is “Yes”, the values of the remaining gasoline amount and the remaining hydrogen amount are read in step S3. In step S4, it is determined whether there is a gasoline remaining amount. If the determination is "No" and the gasoline remaining amount is not present, hydrogen must be selected as the fuel to be used. Then, select hydrogen as the fuel to be used and return.

  If the determination in step S4 is “Yes” and there is a remaining amount of gasoline, it is determined in step S6 whether the remaining amount of hydrogen is equal to or greater than a first predetermined amount. If the determination is “No” and the remaining amount of hydrogen is less than the first predetermined amount, gasoline is selected as the fuel to be used in step S7, and the process returns.

  If the determination in step S6 is “Yes” and the remaining amount of hydrogen is greater than or equal to the first predetermined amount, the catalyst temperature is read in step S8, and then whether or not the catalyst temperature has reached the activation temperature in step S9. If this determination is “No” and the catalyst activation temperature has not been reached, in step S10, hydrogen is selected as the fuel to be used, and the process returns.

  If the determination in step S9 is “Yes” and the catalyst activation temperature has been reached, it is determined in step S11 whether or not the remaining amount of hydrogen is greater than or equal to a second predetermined amount. If the remaining hydrogen amount is not equal to or greater than the second predetermined amount, gasoline is selected as the fuel to be used in step S12, then the instrument's hydrogen fuel exhaust lamp is turned on in step S13, and the fuel is switched in step S14. A switch operation prohibition warning is also displayed on the instrument panel display, and the process returns.

  If the determination in step S11 is “Yes” and the remaining amount of hydrogen is greater than or equal to the second predetermined amount, the fuel selected by the fuel switch is read in step S15, and then the fuel switch in step S16. To determine if hydrogen is selected. If this determination is “Yes” and hydrogen is being selected, in step s17, hydrogen is directly selected as the fuel to be used, and the process returns. If the determination is “No” and gasoline is being selected, then in step S18. Select gasoline as the fuel to be used and return.

The flowchart in FIG. 6 shows a subroutine for changing the predetermined amount by the outside air temperature, and starts at the same time as the engine start command.
In step S101, the detected value of the outside air temperature sensor is read. Next, in step S102, it is determined whether or not the outside air temperature is equal to or lower than a predetermined temperature (for example, 10 ° C.).

  And if the determination of step S102 is "No", it will return as it is. When the determination is “Yes” and the outside air temperature is equal to or lower than the predetermined temperature, the map is changed so that the second predetermined amount is increased, and the process returns.

  How much the second predetermined amount is increased when the outside air temperature is equal to or lower than the predetermined temperature is determined in advance using a map, for example, and different maps are used for normal times and when the outside air temperature is low.

The flowchart of FIG. 7 shows a subroutine for changing a predetermined amount according to the hydrogen fuel replenishment status, and starts at the same time as the engine start command.
In step S201, the average hydrogen consumption from the time when the hydrogen fuel shortage lamp is lit until the hydrogen fuel supply is read.

  If the determination in step S202 is “No”, the process directly returns. If the determination is “Yes” and the average hydrogen consumption is greater than or equal to a predetermined amount, the map is changed in step S203 so that the second predetermined amount is increased.

  As mentioned above, although an example of embodiment was demonstrated, this invention is not limited to this, It can implement with a various form.

  For example, although the above embodiment is a case of a series hybrid vehicle, the present invention can also be applied to a normal dual fuel engine vehicle in which only the engine output is the driving force of the vehicle.

  As the fuel used for the engine, light oil or the like may be used as the liquid fuel, and CNG or the like may be used as the gaseous fuel.

  In the above embodiment, the driver operates the instrument panel switch as a fuel switching condition. However, when the required torque of the vehicle is small, the driver automatically switches to hydrogen, which is difficult to generate engine torque. When the torque is large, it may be automatically switched to gasoline that produces engine torque. A plurality of such switching conditions may be provided.

1 is an overall view of a vehicle drive system equipped with a dual fuel engine according to an embodiment of the present invention. It is a control block diagram of the dual fuel engine of the embodiment of the present invention. It is basic concept explanatory drawing of the fuel switching control of the dual fuel engine of embodiment of this invention. It is a detailed conceptual explanatory view of the fuel switching control of the dual fuel engine of the embodiment of the present invention. It is a flowchart which shows the main routine of the fuel switching control of the dual fuel engine of embodiment of this invention. It is a flowchart which shows an example of the subroutine of the fuel switching control of the dual fuel engine of embodiment of this invention. It is a flowchart which shows the other example of the subroutine of the fuel switching control of the dual fuel engine of embodiment of this invention.

Explanation of symbols

1 engine (dual fuel engine)
2 Gasoline fuel tank 3 Hydrogen fuel tank 7 Generator (generator)
10 Motor (electric motor)
11 Battery (High voltage battery)
12 AC-DC converter 14 DC-AC converter 108, 109 Fuel injection valve 110, 111 for gasoline Fuel injection valve 120 for hydrogen 120 Computer (PCM)
121 Battery Current / Voltage Sensor 122 Hydrogen Fuel Tank Pressure Sensor 123 Gasoline Fuel Tank Fuel Sensor 124 Fuel Changeover Switch 125 Outside Air Temperature Sensor 126 Catalyst Temperature Sensor

Claims (4)

A control device for a dual fuel engine that can be operated by switching the fuel used between liquid fuel and gaseous fuel,
Means for detecting a value related to the remaining amount of gaseous fuel and determining the remaining amount of gaseous fuel;
Means for detecting the value related to the active state of the catalyst for exhaust purification and determining the active state of the catalyst;
First fuel selection means for using gaseous fuel as a fuel when the catalyst is not activated;
Second fuel selecting means for prohibiting switching to the gaseous fuel by the first fuel selecting means when the remaining amount of the gaseous fuel is equal to or less than a first predetermined amount, and using the used fuel as liquid fuel;
Third fuel selection means for selecting a fuel to be used when a predetermined condition is satisfied after the catalyst is activated;
Fourth fuel selection means for selecting the liquid fuel as the used fuel while prohibiting the switching of the used fuel by the third fuel selecting means when the remaining amount of the gaseous fuel is equal to or less than the second predetermined amount larger than the first predetermined amount. A dual fuel engine control device comprising: The predetermined condition is established when an occupant operates a predetermined switch, and the prohibiting means prohibits switching of the fuel used by the switch when the remaining amount of gaseous fuel is equal to or less than the second predetermined amount. The dual fuel engine control device according to claim 1, wherein The means according to claim 1 or 2, further comprising means for detecting a value related to the outside air temperature to determine the outside air temperature, and means for increasing the second predetermined amount when the outside air temperature is equal to or lower than a predetermined temperature. Control device for dual fuel engine. A value related to the amount of gaseous fuel consumed until the gaseous fuel is replenished after the remaining amount of gaseous fuel reaches a level that requires refueling is detected to determine the amount of gaseous fuel consumed after replenishment is requested. 4. The dual fuel engine control device according to claim 1, further comprising means for increasing the second predetermined amount as the consumption amount increases.

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