KR20140013042A - Control method and controller of marine engine - Google Patents

Abstract

(assignment)
The fuel saving mode and the normal mode are efficiently switched to maintain fuel efficiency while improving the fuel efficiency.
(Solution)
The set rotational speed and the actual rotational speed are inputted to the controller 4 and the PID controller 12 calculates an output value from the difference between the set rotational speed and the actual rotational speed in the normal mode to the fuel supply means of the marine engine 2 . The PID controller 12 also has a fuel save mode that reduces the change width of the output value per unit time as compared with the normal mode. (20, 22, 24, 26, 28) for monitoring the variation of the set rotation speed and the actual rotation speed. When the set rotation speed or the actual rotation speed exceeds the predetermined range in the fuel save mode, The PID controller 12 is switched to the normal mode by the output.

Description

TECHNICAL FIELD [0001] The present invention relates to a control method for a marine engine,

The present invention relates to a control method for an engine for a ship having a speed control device and a control device used in the method.

The ship engine is provided with a governor (governor) for controlling the fuel control parameters such as the fuel injection amount so that the number of revolutions is adjusted to the target revolutions set by the operator. As this governor, for example, as disclosed in Patent Document 1, the actual rotational speed and the set rotational speed of a ship engine are compared with each other, and the rack position of the fuel pump provided in the ship engine is adjusted in accordance with the result of this comparison And the fuel supply amount of the main engine is adjusted in accordance with the deviation between the actual engine speed and the set engine speed, as disclosed in Patent Document 2.

Japanese Patent Application Laid-Open No. 7-279738 Japanese Patent Application Laid-Open No. 8-200131

According to the techniques of the above Patent Documents 1 and 2, the rack position of the sequential fuel pump is adjusted according to the result of the comparison operation, and the adjustment of the sequential fuel supply amount is performed according to the deviation between the actual rotation speed and the set rotation speed . If the adjustment of the position of the rack and the adjustment of the fuel supply amount are carried out, the rotational speed of the ship engine is always controlled constantly, but the fuel may be unnecessarily consumed. On the other hand, when the sequential control is stopped, the number of revolutions of the ship engine is varied, but the consumption of fuel can be suppressed. Therefore, it is preferable to suitably switch between a state in which the rotation number is constantly controlled and a state in which the rotation control is stopped.

It is also possible to perform control to reduce the fluctuation of the supply amount of the fuel by lowering the rate of change of the parameter used for the control instead of the sequential control. However, in this case, the actual number of revolutions does not coincide with the number of revolutions set by the operator, which makes it difficult to ship.

The present invention relates to a control method for a marine engine which can improve fuel efficiency by efficiently switching to a mode for prohibiting a change of an output value to a fuel supply means while maintaining ship maneuverability, And a control device therefor.

One aspect of a control method for a marine engine according to the present invention is a control method for a marine engine, comprising: a normal mode for changing an output value from a difference between a set rotation speed set by a maneuver and an actual rotation speed, Or a fuel save mode for reducing the change width per unit time as compared with the normal mode. The fuel supply means may be an actuator for controlling the fuel pump in the case of mechanical control or an electromagnetic valve in the case of electronic control. And is switched from the fuel saving mode to the normal mode under a predetermined condition.

In one form of the control device used in this method, an arithmetic means for calculating the output value to the fuel supply means by the normal mode and the fuel saving mode is provided. In addition, monitoring means for monitoring fluctuations of the set rotation speed or the actual rotation speed is provided. The monitoring means generates a release command when the set number of revolutions or the actual number of revolutions exceeds the predetermined range, and the computation means receives the release command and switches to the normal mode.

Since the normal mode and the fuel saving mode are switched as described above, the fuel efficiency can be improved in the fuel saving mode while maintaining the shipbuilding property in the normal mode.

In the control method of the above-described aspect, the predetermined condition may be set when the actual rotational speed is out of the range of the rotational speed set for safe operation against marine or disturbance. In the above-described control device, the monitoring means can generate a release command when the actual rotation speed becomes equal to or lower than the rotation speed set for securing the shipbuilding property.

With such a configuration, for example, in the case where there is a possibility that the safe running becomes difficult due to a change in disturbance, the normal mode is switched and the shipbuilding property is improved. Further, when safe operation is possible, fuel consumption can be suppressed by the fuel save mode.

In the control method of the above-mentioned aspect, the predetermined condition may be set when the actual rotational speed becomes equal to or lower than the rotational speed used in the outward appearance. In the control device of this type, the monitoring means can generate a release command when the actual rotational speed becomes equal to or lower than the rotational speed used in the appearance.

If such a configuration is employed, for example, if the actual rotational speed becomes lower than the rotational speed used in the appearance and there is a possibility that the safe running becomes difficult, the fuel saving mode is switched from the fuel saving mode capable of suppressing fuel consumption to the normal mode, .

In the control method of the above aspect, the predetermined condition may be set when the actual rotational speed is equal to or greater than the rotational speed set for preventing rotation. In the above-described control device, the monitoring means may generate a release command when the actual rotational speed is equal to or higher than the rotational speed set for preventing rotation.

With such a configuration, when there is a possibility that the actual rotational speed becomes higher than the actual rotational speed, it is possible to prevent the actual rotational speed from becoming excessive due to switching from the fuel save mode to the normal mode.

In the control method of the above aspect, the predetermined condition may be set when the set rotation speed is changed by the operator. In the above-described control device, the monitoring means can generate a cancel command when the set rotation speed is changed by the operator.

With such a configuration, when the operator changes the set rotation speed, the ship is switched to the normal mode and therefore the ship engine can be rotated at the actual rotation speed corresponding to the set rotation speed. Thereafter, the fuel consumption efficiency can be improved by switching to the fuel saving mode and continuing the navigation of the ship.

Further, when the amount of change of the set rotation speed is in the range of fine adjustment, the fuel save mode may be maintained, and the monitoring means may maintain the fuel save mode. As the fine adjustment, for example, there is a set rotation speed of 2 rpm / sec or less. With this configuration, when the set rotation speed is in the range of the fine adjustment, the fuel save mode is maintained, and therefore the fuel consumption efficiency can be improved.

Further, in the control method of the above aspect, when the difference between the set rotation speed and the actual rotation speed in the normal mode is the first range, the control mode is switched to the fuel saving mode, It is possible to switch to the normal mode when the difference of the actual rotation speed is larger than the second range. In this case, the second range is larger than the first range. Likewise, in the control device of the above aspect, the monitoring means stops the release signal when the difference between the set rotation speed and the actual rotation speed in the normal mode is the first range, and the set rotation speed in the fuel save mode And the release signal can be generated when the difference in the actual rotation speed is larger than the second range. In this case also, the second range is larger than the first range.

Since the second range is larger than the first range, it is difficult to switch from the fuel saving mode to the normal mode, so that it is possible to increase the fuel consumption efficiency by prolonging the time required to travel in the fuel saving mode.

Further, in the control method of the above aspect, the output value may be changed to an average value when the normal mode is switched to the fuel saving mode. Alternatively, the controller of the above-mentioned type may be provided with an average value calculating means for calculating an average value of the output values to the fuel supply means, and when switching from the normal mode to the fuel saving mode, A switching means for switching to an average value may be provided.

With such a configuration, it is possible to reduce the change in the number of revolutions of the marine engine in the fuel save mode, so that the switching to the normal mode can be reduced and the fuel consumption efficiency can be improved.

In the control method of the above aspect, the upper limit of the save mode of the output value to the fuel supply means in the fuel save mode may be defined. Alternatively, in the control device of the above-described type, the calculation means may be arranged such that when the fuel saving mode changes the output value of the fuel supply means to a smaller extent than the normal mode, the upper limit of the save mode of the output value to the fuel supply means is defined, When the output value exceeds the upper limit of the save mode, the upper limit of the save mode may be output.

In the fuel saving mode, fluctuation of the actual rotation speed increases in bad weather. However, since the upper limit is set to the output value to the fuel supply means, the change in the fuel supply amount is not excessively increased, . In addition, it is possible to prevent fluctuations of the actual rotation speed from increasing.

In the control method of the above aspect, the proportional integral differential control can be used to calculate the output value to the fuel supply means. In this case, in the fuel saving mode, the proportional gain used for the proportional control in the proportional integral differential control is multiplied by the proportional magnification, the integration time used for the integral control during the proportional integral differential control is multiplied by the integration magnification, The differential value used for the differential control in the proportional integral differential control is multiplied by a differentiation magnification to prohibit the output value from being changed to the fuel supply means or to reduce the change width per unit time of the output value per unit time as compared with the normal mode. In addition, each magnification can be set.

Alternatively, in the above-described control apparatus, the calculation means may include a proportional-integral-derivative control means. In this case, in the fuel save mode, the proportional gain used for the proportional control in the proportional integral derivative control means is multiplied by the proportional magnification, and the integral time used for the integral control of the proportional integral derivative control means is multiplied by the integral magnification , And prohibits the output value to the fuel supply means from being changed by multiplying the derivative time used for the differential control of the proportional integral derivative control means by the differential magnification or to change the output value per unit time of the output value per unit time . In addition, each magnification can be set.

When the proportional gain constant, integral time, and differential time are to be changed in the fuel save mode, these values in the normal mode are first grasped, and the proportional gain constant, integral time, and differential time are newly calculated It needs to be set and the processing is troublesome. On the other hand, if the proportional gain constant, the integral time, and the differential time are multiplied by the magnification, it is not necessary to grasp the proportional gain constant, the integral time, and the differential time in the normal mode.

1 is a block diagram of a control apparatus for an engine for a ship according to an embodiment of the present invention.
Fig. 2 is a block diagram showing the functions achieved by the controller shown in Fig. 1. Fig.

A control apparatus for an engine for a ship according to an embodiment of the present invention controls an engine for a ship, for example, an internal combustion engine 2 for a ship as shown in Fig. The marine internal combustion engine 2 is, for example, a multi-cylinder diesel engine. Although not shown, each cylinder is provided with a fuel injection valve and a fuel supply means, for example, a fuel injection pump. The fuel injection valve supplies the supplied fuel to the corresponding cylinder when the pressure of the fuel supplied from the fuel injection pump is equal to or higher than a predetermined pressure. Each fuel injection pump supplies a fuel to the corresponding fuel injection valve based on an output value from a control device, for example, the controller 4, which will be described later. The marine internal combustion engine 2 may be provided with a fuel injection valve or a fuel injection pump, and the fuel supply may be controlled by a solenoid valve for each cylinder, for example, a common rail type or a pressurized cylinder type fuel injection system . In addition, each cylinder may be provided with fuel supply means, for example, an injector as a fuel injection valve. The injector controls the fuel injection in the corresponding cylinder by moving the valve body by magnetizing or demagnetizing the electromagnets provided inside the injector, and is controlled based on the output value of the controller 4.

The controller 4 includes arithmetic means, for example, a microprocessor and a storage means, for example, a ROM and a RAM. An actual rotation number signal indicative of the actual rotation number, which is the actual rotation number of the marine internal combustion engine 2, is supplied from the rotation number detector 6 to the controller 4. The controller 4 is also supplied with a set rotational speed signal indicating the set rotational speed of the marine internal combustion engine 2 from the steering device 8. [

In the present embodiment, the controller 4 functions as an adding means for calculating the deviation between the set rotation speed signal and the actual rotation speed signal, for example, the adder 10 as shown in Fig. 2, and the PID And also functions as a control means, for example, a PID controller 12. That is, the PID controller 12 multiplies the supplied deviation by a proportional gain constant, performs proportional control, integrates the supplied deviation, multiplies the supplied deviation by the reciprocal of the integral time to perform integral control, differentiates the supplied deviation And outputs a value obtained by adding the respective values obtained by the proportional control, integral control, and differential control as an output value.

Further, the PID controller 12 is provided with a limiter 14. When the calculated output value exceeds the limiter upper limit set in the limiter 14, the limiter 14 is configured to output the limiter upper limit value.

The PID controller 12 is configured to operate in the selected mode, out of the normal mode and the fuel save mode.

In the normal mode, the offset does not occur even when the set rotation speed signal changes, and the proportional gain constant, integral time, and differential time are set so that the actual rotation speed signal coincides with the set rotation speed signal quickly.

In the fuel save mode, the integral time and the derivative time are set so that the force of the integral control action becomes stronger than the normal mode and the differential control is hardly effected. In addition, the proportional gain constant is set so that the force of the proportional control action becomes smaller than the proportional control of the normal mode. By doing so, the fluctuation per unit time of the output value of the PID controller 12 is smaller than that in the normal mode.

The setting of the proportional gain constant, the integral time, and the differential time in the fuel save mode does not change these per se but changes the initial value, for example, the proportional gain constant of the normal mode, the integral time, And multiplying the time magnification and the differential time magnification, respectively. Therefore, even if the proportional gain constant, the integral time, and the differential time itself in the normal mode are not grasped, only the proportional gain constant in the normal mode, several times of the integral time and several times the same differential time So that the setting becomes easy. Also, the proportional gain constant magnification, the integral time magnification, and the differential time magnification can be set by the operator, respectively.

Switching between the fuel saving mode and the normal mode will be described later.

The controller 4 also functions as a filter 16, for example a low-pass filter, which averages the output of the PID controller 12. Switching means 18 for selecting one of the output of the filter 16 and the output of the PID controller 12 to supply the fuel to the fuel injection pump or the injector in the internal combustion engine 2 for marine vessel, ) Function. In the normal mode, the changeover switch 18 directly supplies the output of the PID controller 12 to the fuel injection pump or the injector. However, as described later, the switching control section 19 constituted by the controller 4, for example, When the mode is switched from the normal mode to the fuel saving mode, the output of the filter 16 is supplied to the fuel injection pump or the injector for a predetermined period or one loop period of the control program.

In order to determine the switching between the normal mode and the fuel save mode, the controller 4 also functions as a monitoring means, for example, five detecting portions. The actual rotation speed level detection section 22, the setting rotation speed level detection section 24, the setting rotation speed variation amount detection section 26 and the rotation speed variation amount detection section 28 Is installed.

The actual rotational speed over-speed level detecting section 20 receives an actual rotational speed signal and judges whether or not it is equal to or greater than a predetermined over-speed level. When the actual rotational speed signal is equal to or higher than the over- And outputs an ON signal for switching to the fuel save mode when the actual rotation speed signal is less than the over speed level. The over-speed level is set to a level at which it is possible to determine that the marine internal combustion engine 2 is over rotating. Therefore, when the marine internal combustion engine 2 is over rotating in the fuel save mode, it can be switched to the normal mode, and when the marine internal combustion engine 2 is not over rotating in the normal mode, it can be switched to the fuel saving mode Do.

The actual rotation speed level detector 22 receives the actual rotation speed signal and determines whether or not the actual rotation speed signal is equal to or greater than the navigation full rotation speed. If the actual rotation speed signal is equal to or greater than the navigation full rotation speed, And outputs an ON signal when the actual rotation number signal is less than the navigation full rotation number. The navigation full rotation number indicates the number of revolutions when the marine internal combustion engine 2 is used in an appearance. Therefore, when the actual rotation speed signal is equal to or greater than the navigation full rotation speed in the fuel save mode, it is switchable to the normal mode. Further, when the actual rotation speed signal is less than the navigation full rotation speed in the normal mode, it is possible to switch to the fuel saving mode. The navigation full rotation number is the number of revolutions during out-of-sight navigation calculated in advance from the shape and size of the ship. In addition, the number of revolutions that can safely be navigated by taking into consideration maritime disturbance and the like is calculated in advance while the inside of the vehicle is navigated. If the actual number of revolutions is equal to or greater than the calculated number of revolutions during navigation, OFF signal, and outputs an ON signal when the actual rotation number signal is less than the calculated rotation number.

The setting rotation speed level detector 24 receives the setting rotation speed signal, determines whether or not the rotation speed is equal to or greater than the navigation full rotation speed, outputs an OFF signal when the rotation speed is equal to or greater than the navigation full rotation speed, . Therefore, when the set rotation speed signal is equal to or greater than the navigation full rotation speed in the fuel save mode, it is switchable to the normal mode. Further, in the normal mode, when the set rotation speed signal is less than the navigation full rotation speed, it is possible to switch to the fuel save mode.

The set rotational speed variation detecting unit 26 receives the set rotational speed signal and calculates a unit time, for example, a rate of change per second, and determines whether or not the rate of change is a predetermined value, for example, 2 rpm / second or more 2 rpm / second or more, and outputs an ON signal when the rotational speed is less than 2 rpm / second. The predetermined value is set to a value that can be regarded as a range of fine adjustment by the amount of change in the set rotation speed. Therefore, when the amount of change of the set rotation speed in the fuel saving mode is out of the range of fine adjustment, it is possible to switch to the normal mode. When the amount of change in the set rotation speed in the normal mode is within the fine adjustment range, Do.

A deviation signal (a deviation signal between the set rotation speed signal and the actual rotation speed signal) from the adder 10 is input to the rotation speed variation amount detection unit 28. [ This deviation signal indicates a variation with respect to the set rotation speed of the actual rotation speed. When the variation amount is within a predetermined first range, for example, ± 3 rpm, the ON signal is outputted. 2, for example, +5 rpm or -5 rpm or less. Therefore, when the variation in the number of revolutions, which is a deviation signal between the set rotation speed signal and the actual rotation speed signal, is increased by 5 rpm or more or -5 rpm or less in the fuel save mode, it is possible to switch to the normal mode. Further, in the normal mode, when the variation in the number of revolutions is within a range of 占 3 rpm, it is possible to switch to the fuel saving mode.

The output signals of the respective detectors 20, 22, 24, 26 and 28 are supplied to a logic gate constituted by the controller 4, for example, an AND gate 30. The AND gate 30 generates an output when the output signals of the respective detectors 20, 24, 26, and 28 are all ON signals. This output is supplied to the timer 32 constituted by the controller 4. The timer 32 generates an output when the output of the AND gate 30 continues for a predetermined time. Therefore, even if all of the detectors 20, 22, 24, 26, and 28 output the ON signal only for a short time, the timer 32 does not generate an output and all the detectors 20, 22, 24, When the ON signal is generated over time, the timer 32 generates an output. The output of the timer 32 is supplied to the fuel saving mode ready display portion 36 provided in the display device 34 shown in Fig. 1, and it is turned on to indicate that the fuel saving mode is ready.

The output of the timer 32 is supplied to a logic gate constituted by the controller 4, for example, an AND gate 38. [ A fuel save mode selection signal generated when the fuel save mode selection button 40 provided in the control device 8 is closed is also supplied to the end gate 38. The AND gate 38 generates the output only when the timer 34 supplies the output and the fuel save mode selection signal is also being supplied from the fuel save mode selection button 40. [ Therefore, even if the timer 32 generates an output, that is, even if all of the detectors 20, 22, 24, 26, and 28 generate an ON signal over a predetermined period of time, as long as the fuel save mode selection signal is not supplied And the AND gate 38 does not generate an output.

The output of the AND gate 38 is supplied to the PID controller 12. The PID controller 12 is switched from the normal mode to the fuel save mode by receiving the supply of the output of the end gate 38 to perform the PID control in the fuel save mode. At the same time, the output of the AND gate 38 is supplied to the fuel saving mode indicator 42 provided in the indicator 34 to indicate the transition to the fuel saving mode. Conversely, when the output of the AND gate 38 is not supplied to the PID controller 12, the PID controller 12 is switched from the fuel save mode to the normal mode.

The output of the AND gate 38 is supplied to the switching control section 19 and the switching control section 19 switches the changeover switch 18 to supply the output of the filter 16 to the fuel injection pump or the injector. The output value of the PID controller 12 is changed by switching from the normal mode to the fuel saving mode. In addition, since the filter 16 is supplied to the fuel injection pump or the injector at the initial stage of the switching, variation during switching can be suppressed. After a predetermined period of time elapses, the changeover switch 18 is switched, and the output of the PID controller 12 is directly supplied to the fuel injection pump or the injector.

As described above, when all of the detectors 20, 22, 24, 26, and 28 output the ON signal for a predetermined time in the normal mode, the PID controller 12 is switched to the fuel save mode, And outputs an output value for controlling the fuel injection pump or the injector in the save mode. However, if any one of the detectors 20, 22, 24, 26, and 28 outputs an OFF signal in this fuel save mode, the PID controller 12 is switched to the normal mode and the PID controller 12 And outputs an output value for controlling the fuel injection pump or the injector.

Therefore, when the actual rotation speed increases to over the over speed level, when the actual rotation speed increases to more than the navigation full rotation speed, when the set rotation speed increases by 2 rpm or more, when the set rotation speed increases to more than the navigation full rotation speed, When the fluctuation amount of the rotation speed changes by more than ± 5 rpm, the control is switched to the normal mode even if the control is performed in the fuel saving mode until now, so that the safety navigation is not affected and the shipability is improved. Further, the fuel consumption amount is suppressed during the fuel save mode.

In addition, since the output of the PID controller 12 is averaged by the filter 16 for a predetermined period switched to the fuel save mode, the output value supplied to the fuel injection pump or the injector does not fluctuate sharply. As a result, it is possible to prevent the fluctuation amount of the rotational speed of the marine engine 2 from changing back to the normal mode immediately after switching to the fuel saving mode without largely varying.

Further, since the PID controller 12 is provided with the limiter 14, the output value thereof does not become larger than the upper limit value of the limiter, and the amount of change in the fuel does not abnormally increase, thereby preventing over rotation. In the fuel save mode, the amount of operation of the actuator or the injector becomes extremely small. Therefore, there is a possibility that the rotation speed fluctuation becomes larger than the normal mode after switching to the fuel save mode. Therefore, this limiter 14 is provided. It is also preferable that the limiter 14 has a value which is 5 to 10% lower than the upper limit of the output of the PID controller 12 in the normal mode.

Although the five detecting portions 20, 22, 24, 26, and 28 are provided in the above embodiment, a desired one or a plurality of these detecting portions may be used depending on the situation. And the end gate 30 is unnecessary when the single detecting portion 30 is used. The fuel saving mode selection button 40 and the end gate 38 are removed to set the fuel saving mode selection button 40 and the fuel saving mode selection signal to the end gate 38, The output may be directly supplied to the PID controller 12, the switching control unit 19, and the fuel saving mode display unit 42. The timer 32, the filter 46, the changeover switch 18, and the switching control unit 19 may be removed depending on the situation.

In the above embodiment, the PID controller 12 continues the PID control by setting the proportional gain constant, the integral time, and the differential time to a different value from the normal mode in the fuel saving mode, And the output value of the PID controller 12 immediately before the stop of the control is outputted as it is.

Claims (8)

The normal mode for changing the output value to the fuel supply means from the difference between the set rotational speed set by the operator and the actual rotational speed, which is the actual rotational speed of the marine engine, and the change of the output value is prohibited or the above per unit time compared to the normal mode. In the control method of the ship engine which is equipped with the fuel save mode which makes small the change width of an output value, and switches to the said normal mode from the said fuel save mode on predetermined conditions,
The predetermined condition is that the fuel save mode is maintained when the set rotational speed is changed by the operator and when the amount of change in the set rotational speed is finely adjusted. The method of claim 1,
When the difference between the set rotation speed and the actual rotation speed in the normal mode is the first range, the fuel saving mode is switched, and the difference between the set rotation speed and the actual rotation speed in the fuel save mode is greater than the second range The second range is larger than the first range, and the second range is larger than the first range. The method of claim 1,
And the output value is changed to an average value when switching between the normal mode and the fuel save mode. The method of claim 1,
The control method of the marine engine characterized by the upper limit of the save mode of the said output value at the said fuel save mode. As a control apparatus used for the control method of the marine engine of Claim 1,
To the control apparatus of the marine engine provided with the calculation means which has a normal mode which a predetermined rotation speed and an actual rotation speed are input, and calculates the output value to the fuel supply means of the said marine engine from the difference of the said predetermined rotation speed and the said actual rotation speed. In
The computing means has a fuel save mode that prohibits the change of the output value or decreases the change width of the output value per unit time compared to the normal mode, and is configured to be switchable between the normal mode and the fuel save mode,
And a monitoring means for monitoring the variation of the set rotation speed or the actual rotation speed, wherein when the set rotation speed or the actual rotation speed exceeds a predetermined range,
In the control apparatus of the marine engine which receives the said release command and switches to the said normal mode,
The monitoring means sends the release command when the set rotational speed is changed by the operator, and the monitoring means maintains the fuel save mode when the amount of change in the set rotational speed is within the fine adjustment range. A control apparatus of a marine engine, characterized in that. The method of claim 5, wherein
The monitoring means stops the release command when the difference between the set rotational speed and the actual rotational speed is within the first range in the normal mode, and the difference between the set rotational speed and the actual rotational speed is set to zero in the fuel save mode. The said release command is sent when it exceeds 2 range, and the 2nd range is set larger than a 1st range, The control apparatus of the ship engine. The method of claim 5, wherein
An average value calculating means for calculating an average value of the output values is provided, and a switching means for switching the output value to the average value when switching from the normal mode to the fuel save mode is provided. The method of claim 5, wherein
The computing means defines a save mode upper limit of the output value when the fuel save mode makes a change in the output value smaller than the normal mode, and when the calculated output value exceeds the save mode upper limit, A control apparatus of a marine engine, characterized in that for outputting the save mode upper limit.

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