JP2008045484A - Control method and control device for marine internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a marine internal combustion engine capable of reducing quantity of fuel consumed by an internal combustion engine as compared with former devices. <P>SOLUTION: In the control device for the marine internal combustion engine 1 provided with a governor device 10 changing combustion control parameter of the internal combustion engine 1 to control speed of the internal combustion engine 1 to target speed, a controller 11 of the governor device 10 controls change of combustion control parameters due to load fluctuation of the internal combustion engine 1 when the target speed is established in a predetermined speed range. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control method and a control device for a marine internal combustion engine provided with a speed governing device that changes a combustion control parameter of the internal combustion engine such as a fuel injection amount in order to adjust the rotational speed of the internal combustion engine to a target rotational speed.

  Generally, a marine internal combustion engine is provided with a speed governor for controlling a combustion control parameter such as a fuel injection amount so-called a governor so that the rotational speed of the internal combustion engine is adjusted to a target rotational speed set by a driver. . As an apparatus for controlling the rotational speed of such an internal combustion engine, for example, the actual rotational speed of the engine is compared with a set rotational speed, and the rack position of the fuel pump is adjusted on the basis of the result of the comparative computation, so that the internal combustion engine is A rotation speed control device that adjusts the fuel injection amount to be supplied is known (see Patent Document 1). Also, an electronic governor device for a marine main engine that adjusts the fuel supply amount of the main engine in accordance with the deviation between the command speed and the actual speed is known (see Patent Document 2).

JP-A-7-29738 Japanese Patent Laid-Open No. 8-200231

  The speed governor changes combustion control parameters such as the fuel supply amount so that the rotational speed of the internal combustion engine matches the target rotational speed. On the other hand, depending on the situation, there is a possibility that the stability of the operation of the internal combustion engine can be ensured even if the rotational speed of the internal combustion engine varies to some extent with respect to the target rotational speed. If control is performed to match the target rotational speed in such a situation, the operating state of the internal combustion engine may be changed wastefully and fuel may be consumed wastefully.

  Accordingly, an object of the present invention is to provide a control method and a control device for a marine internal combustion engine that can reduce the amount of fuel consumed in the internal combustion engine as compared with the conventional art.

  The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiment.

  The marine internal combustion engine control method of the present invention includes speed control means (10, 40) for changing combustion control parameters of the internal combustion engine so that the rotational speed of the internal combustion engine (1) is adjusted to a target rotational speed. In the control method for a marine internal combustion engine, when the target rotational speed is set within a predetermined rotational speed range, by restricting the change of the combustion control parameter by the speed control means at the time of load fluctuation of the internal combustion engine, The above-described problems are solved.

  As a value indicating the performance of the internal combustion engine, a fuel consumption rate which is a value obtained by dividing the fuel consumption by the shaft output, in other words, a value indicating the amount of fuel consumed per unit time and unit shaft output is known. The fuel consumption rate has a correlation with the rotational speed of the internal combustion engine and the torque of the internal combustion engine, and the change in the rotational speed of the internal combustion engine is more fuel than the influence of the change in the torque of the internal combustion engine on the change in the fuel consumption rate. The effect on consumption rate changes is smaller.

  In the control method of the present invention, when the target rotational speed is set within a predetermined rotational speed range, the change of the combustion control parameter by the speed control means is limited. When the change of the combustion control parameter by the speed control means is restricted, the torque fluctuation of the internal combustion engine can be suppressed, so that the fluctuation of the fuel consumption rate can be suppressed. On the other hand, when the engine speed is forcibly matched to the target engine speed without restricting the change of the combustion control parameter, the torque fluctuation of the engine is smaller than when the change of the combustion control parameter is restricted. In response, the fluctuation of the fuel consumption rate also increases. For this reason, the fuel consumption rate fluctuates more wastefully than when the change of the combustion control parameter is restricted, and the frequency at which the fuel consumption rate increases increases. According to the control method of the present invention, it is possible to limit the change in the combustion control parameter by the speed control means and suppress the wasteful fluctuation of the fuel consumption rate, and thus it is possible to suppress the wasteful fuel consumption. Therefore, the amount of fuel consumed in the internal combustion engine can be reduced as compared with the conventional art.

  The concept of “limit” in the present invention is that the control effect of the rotational speed adjustment control when the target rotational speed is set within a predetermined rotational speed range is the target rotational speed outside the predetermined rotational speed range. Change the combustion control parameter so that it is weaker than the control effect of the rotational speed adjustment control when the engine is set, the combustion control parameter by the speed control means responding to some of the disturbances received by the ship Both of prohibiting the change of the engine and prohibiting the change of the combustion control parameter by the speed control means are included.

  The term “disturbance” in the present invention refers to waves, winds, tidal currents, and the like that act on a ship to change the load of the internal combustion engine.

  In one form of the control method of the present invention, the predetermined rotational speed range is equal to or more than a minimum value of a target rotational speed set for the internal combustion engine during open sea voyage, and prevents the internal combustion engine from over-rotating. A rotation speed range equal to or lower than the excessive rotation prevention rotation speed set for the purpose may be set. In such a rotational speed range, the stability of the operation of the internal combustion engine can be ensured even if the load of the internal combustion engine varies and the rotational speed of the internal combustion engine varies to some extent.

  In one form of the control method of the present invention, when the target rotational speed is set within the predetermined rotational speed range, the combustion control parameter is changed by the speed control means when the internal combustion engine changes in load. It may be prohibited. Thus, by prohibiting the change of the combustion control parameter, it is possible to further suppress the fluctuation of the torque of the internal combustion engine and further suppress the fluctuation of the fuel consumption rate. Therefore, the amount of fuel consumed in the internal combustion engine can be further reduced.

  In one form of the control method of the present invention, when the target rotational speed is set within the predetermined rotational speed range, a high-frequency disturbance higher than a predetermined frequency among disturbances that vary the load of the internal combustion engine. The change of the combustion control parameter by the speed control means may be prohibited. Even if the combustion control parameter is changed, the rotational speed of the internal combustion engine does not immediately change to the rotational speed determined according to the changed combustion control parameter. For this reason, if the speed control means changes the combustion control parameter in response to a high-frequency disturbance among disturbances received by the ship, the combustion control parameter is changed in a short period when the speed control means changes the combustion control parameter. Even if the control parameter is changed, the combustion control parameter is further changed before the rotational speed of the internal combustion engine changes to the rotational speed determined according to the changed combustion control parameter. That is, the rotation speed of the internal combustion engine cannot follow the change of the combustion control parameter by the speed control means. Therefore, if the combustion control parameter is changed in such a short cycle, the operating state of the internal combustion engine is changed wastefully, so that fuel is wasted. In this embodiment, since the response of the speed control means to a disturbance having a frequency higher than a predetermined frequency is prohibited, useless fuel consumption can be suppressed by suppressing useless fluctuations in the operating state of the internal combustion engine. In addition, by causing the speed control means to respond to a low frequency disturbance equal to or lower than a predetermined frequency, the rotational speed of the internal combustion engine can be stably maintained at the target rotational speed.

  In this embodiment, the predetermined frequency includes the reciprocal of the time constant of the response from when the combustion control parameter is changed until the rotational speed of the internal combustion engine reaches a predetermined rotational speed determined according to the changed combustion control parameter. May be set. By setting the predetermined frequency in this way, it is possible to prohibit the useless response of the speed control means in which the combustion control parameter is changed before the rotational speed of the internal combustion engine reaches the predetermined rotational speed.

  The control apparatus for a marine internal combustion engine of the present invention includes speed control means (10, 40) for changing a combustion control parameter of the internal combustion engine so that the rotational speed of the internal combustion engine (1) is adjusted to a target rotational speed. In the control device for a marine internal combustion engine, when the target rotational speed is set within a predetermined rotational speed range, limiting means for limiting the change of the combustion control parameter by the speed control means when the load of the internal combustion engine changes. By providing (11, 40), the above-described problems are solved.

  According to the control device for a marine internal combustion engine of the present invention, the limiting means limits the change of the combustion control parameter when the target rotational speed is set within a predetermined rotational speed range. Unnecessary fluctuations in the fuel consumption rate can be suppressed. Therefore, wasteful fuel consumption can be suppressed, and the amount of fuel consumed in the internal combustion engine can be reduced as compared with the prior art.

  In one form of the control device of the present invention, the predetermined rotational speed range is equal to or greater than a minimum value of a target rotational speed set for the internal combustion engine during open sea voyage, and prevents the internal combustion engine from over-rotating. A rotation speed range equal to or lower than the excessive rotation prevention rotation speed set for the purpose may be set. In this case, the stability of the operation of the internal combustion engine can be ensured even if the change of the combustion control parameter is limited.

  In one form of the control device of the present invention, the limiting means may prohibit the change of the combustion control parameter by the speed adjusting means when the load of the internal combustion engine changes. In this case, since fluctuations in the fuel consumption rate can be further suppressed, the amount of fuel consumed by the internal combustion engine can be further reduced.

  In one form of the control device of the present invention, the limiting means prohibits the change of the combustion control parameter by the speed adjusting means for a high-frequency disturbance higher than a predetermined frequency among disturbances that fluctuate the load of the internal combustion engine. May be. In this embodiment, the predetermined frequency includes a time constant of a response from when the combustion control parameter is changed until the rotational speed of the internal combustion engine reaches a predetermined rotational speed determined according to the changed combustion control parameter. The reciprocal number of may be set. In this case, since the response of the speed control means to high-frequency disturbances can be prohibited and useless fluctuations in the operating state of the internal combustion engine can be suppressed, wasteful fuel consumption can be suppressed. Further, by causing the speed control means to respond to a low-frequency disturbance, the rotational speed of the internal combustion engine can be stably maintained at the target rotational speed.

  In one aspect of the control apparatus of the present invention, the internal combustion engine includes a fuel injection valve that injects fuel into a cylinder of the internal combustion engine, fuel that supplies fuel to the fuel injection valve, and fuel to be supplied to the fuel injection valve A fuel injection pump (3) capable of changing the amount, and the speed control means supplies the fuel injection valve from the fuel injection pump so that the rotational speed of the internal combustion engine is adjusted to a target rotational speed. The limiting means changes the amount of fuel supplied from the fuel injection pump to the fuel injection valve when the target rotational speed is set within the predetermined rotational speed range. You may restrict. By limiting the change in the amount of fuel supplied from the fuel injection pump to the fuel injection valve in this way, fluctuations in the amount of fuel supplied into the cylinder can be suppressed, and therefore fluctuations in torque of the internal combustion engine can be suppressed. As a result, it is possible to reduce the amount of fuel consumed by suppressing unnecessary fluctuations in the fuel consumption rate.

  In one form of the control device of the present invention, the internal combustion engine includes a fuel injection valve (30) for injecting fuel into the cylinder of the internal combustion engine, and the cylinder from the fuel injection valve based on an operating state of the internal combustion engine. A fuel amount calculating means (40) for calculating the amount of fuel to be injected into the fuel, and controlling the operation of the fuel injection valve so that the fuel amount calculated by the fuel amount calculating means is injected into the cylinder. Operation control means (40), and the fuel amount calculation means functions as the speed control means by calculating the fuel amount so that the rotational speed of the internal combustion engine is adjusted to the target rotational speed. The restricting unit may control the operation of the fuel injection valve so that a change in the amount of fuel injected from the fuel injection valve is restricted. By limiting the change in the amount of fuel injected from the fuel injection valve in this way, it is possible to suppress the torque fluctuation of the internal combustion engine, and thus it is possible to suppress the useless fluctuation of the fuel consumption rate. Therefore, the amount of fuel consumed in the internal combustion engine can be reduced as compared with the conventional case.

  As described above, according to the present invention, when the target rotational speed is set within the predetermined rotational speed range, the change of the combustion control parameter by the speed control means is limited. It is possible to suppress wasteful fluctuations in the fuel consumption rate. Therefore, wasteful consumption of fuel can be suppressed, and the amount of fuel consumed in the internal combustion engine can be reduced as compared with the prior art.

(First form)
FIG. 1 shows an example of an internal combustion engine in which a control device according to the first embodiment of the present invention is incorporated. An internal combustion engine 1 in FIG. 1 is a multi-cylinder diesel engine mounted on a ship as a main engine, and a propeller 2 is provided on an output shaft 1a thereof. Hereinafter, the internal combustion engine 1 may be referred to as an engine. The engine 1 includes a fuel injection valve (not shown) and a fuel injection pump 3 for each cylinder. The fuel injection valve is a well-known one that injects fuel into the cylinder when the pressure of the fuel supplied from the fuel injection pump 3 exceeds a predetermined pressure. The fuel injection pump 3 supplies fuel to the fuel injection valve by reciprocating a plunger inserted into the plunger barrel, and a fuel discharge port provided in the plunger barrel and an oblique groove formed in the plunger This is a well-known device that can change the amount of fuel supplied to the fuel injection valve by changing the relative position.

  The engine 1 is provided with a governor device 10 as adjusting means for adjusting the rotational speed of the engine 1 to a target rotational speed. The governor device 10 includes a controller 11, an actuator 12, and a driver 13 that operates the actuator 12 based on an output signal from the controller 11. As shown in FIG. 1, the actuator 12 is connected to the plungers of the fuel injection pumps 3,. The motion transmission mechanism 14 converts the motion of the actuator 12 into a rotational motion that rotates the plungers of the fuel injection pumps 3,... The rotational motion transmitted to the plungers of the fuel injection pumps 3,... 3 by the motion transmission mechanism 14 rotates the plungers to change the relative positions of the fuel discharge ports of the plunger barrel and the plunger grooves. Thereby, the fuel supply amount to each cylinder is changed.

  The controller 11 is configured as a computer including a microprocessor and peripheral devices such as RAM and ROM necessary for its operation. As such a controller 11, for example, a known PID controller is provided. The controller 11 is connected to a rotational speed sensor 21 that outputs a signal corresponding to the rotational speed of the engine 1, an intake pressure sensor 22 that outputs a signal corresponding to the pressure of air taken into each cylinder, and the like. In addition to these sensors, various sensors are connected to the controller 11, but their illustration is omitted. The controller 11 is connected with a throttle 23 for setting a target rotational speed and a changeover switch 24 for switching execution (on) or prohibition (off) of rotational speed adjustment by the governor device 10. A command is input to the controller 11 by operating the throttle 23 and the changeover switch 24.

  A method of adjusting the rotational speed by the governor device 10 will be described. The controller 11 detects the actual rotational speed of the engine 1 (hereinafter sometimes abbreviated as the actual rotational speed) based on the output signal of the rotational speed sensor 21, and the detected actual rotational speed and the throttle 23. The difference from the set target speed is calculated. Next, based on the calculated difference, the amount of fuel to be supplied to each cylinder is calculated so that the actual rotation speed and the target rotation speed match, and the calculated fuel volume is supplied from the fuel injection pump 3 to the fuel injection valve. Thus, the actuator 12 is operated via the driver 13 to rotate the plunger of each fuel injection pump 3. Thus, the governor device 10 changes the amount of fuel supplied into each cylinder in order to adjust the actual rotational speed to the target rotational speed.

  FIG. 2 shows a governor control routine that is executed by the controller 11 in order to determine whether or not it is necessary to adjust the rotational speed so that the actual rotational speed matches the target rotational speed. The control routine of FIG. 2 is repeatedly executed at a predetermined cycle while the engine 1 is operating.

  In the control routine of FIG. 2, the controller 11 first determines in step S11 whether or not the target rotational speed is within a predetermined rotational speed range. As the predetermined rotation speed range, the minimum value of the rotation speed set as the target rotation speed when the ship on which the engine 1 is mounted sails in the open ocean (hereinafter sometimes abbreviated as the lowest rotation speed during navigation). In order to prevent over-rotation of the engine 1 as described above, a rotation speed range equal to or less than a preset over-rotation prevention rotation speed is set. When the rotational speed of the engine 1 is higher than the over-rotation preventing rotational speed, it is necessary to quickly reduce the rotational speed of the engine 1 to be equal to or less than the over-rotation preventing rotational speed. On the other hand, since the amount of fuel to be supplied to each cylinder is reduced at a rotational speed less than the minimum rotational speed during voyage, if the control for adjusting the actual rotational speed to the target rotational speed is prohibited, the operating state of the engine 1 is not good. It tends to be stable. Therefore, a predetermined rotation speed range is set to a rotation speed range that is equal to or higher than the lowest rotation speed during navigation and is equal to or lower than the excessive rotation prevention rotation speed. Within this rotational speed range, the stability of the operation of the internal combustion engine can be ensured even if the load of the internal combustion engine varies and the rotational speed of the internal combustion engine varies to some extent.

  If it is determined that the target rotational speed is within the predetermined rotational speed range, the process proceeds to step S12, and the controller 11 determines whether or not a predetermined governor-off condition including that the changeover switch 24 is disabled (OFF) is satisfied. to decide. The predetermined governor-off condition includes, for example, the difference between the average actual rotational speed and the target rotational speed in a predetermined period (for example, 10 minutes) until the current control routine is executed, in addition to the changeover switch 24 being prohibited. Is determined to be satisfied when it is within the preset allowable range. The operator determines whether or not to turn on the changeover switch 24 based on, for example, the wave height or the navigational state of the ship on which the engine 1 is mounted. Note that the switch 24 may not be provided if the controller 11 can determine what the operator determines based on the navigation state of the ship, the wave height, and the like by a plurality of sensors connected to the controller 11. . If it is determined that the predetermined governor-off condition is satisfied, the process proceeds to step S13, and the controller 11 maintains the state of the actuator 12 in the state when the control routine was previously executed and prohibits the adjustment of the rotational speed. Thereafter, the current control routine is terminated.

  On the other hand, if a negative determination is made in step S11 or a negative determination is made in step S12, the process proceeds to step S14, where the controller 11 changes the amount of fuel supplied into each cylinder in order to adjust the actual rotation speed to the target rotation speed. The actuator 12 is operated via the driver 13 as described above. Thereafter, the current control routine is terminated.

  FIG. 3 shows an example of the relationship between the rotational speed of the engine 1 and the torque of the engine 1 and the fuel consumption rate in the engine 1. As shown in FIG. 3, the fuel consumption rate of the engine 1 is the smallest in the region S and increases as the distance from the region S increases. Therefore, fuel consumption can be reduced by adjusting the operating state of the engine 1 so that the fuel consumption rate changes to a region close to the region S. When the rotation speed adjustment by the governor device 10 is prohibited, the state of the actuator 12 is maintained, so that the amount of fuel supplied to each cylinder of the engine 1 is fixed to a predetermined amount. Therefore, the combustion pressure of each cylinder can be made substantially constant, and the fluctuation in torque of the internal combustion engine can be suppressed. In this case, since the rotation speed adjustment is prohibited, the rotation speed of the engine 1 varies greatly as compared with the case where the rotation speed adjustment is executed. An arrow A in FIG. 3 shows an example of fluctuations in the operating state of the engine 1 when the rotation speed adjustment is prohibited in this way.

  On the other hand, when the rotation speed adjustment by the governor device 10 is executed, the rotation speed of the engine 1 is adjusted to be substantially constant, but the amount of fuel supplied to each cylinder is changed in order to execute this rotation speed adjustment. The torque of the engine 1 varies. Therefore, the operating state of the engine 1 in this case shows a variation as shown by an arrow B in FIG.

  When the rotation speed adjustment is executed, the operating state of the engine 1 greatly fluctuates in the vertical direction of FIG. 3 as indicated by the arrow B in FIG. On the other hand, when the rotation speed adjustment is prohibited, the operating state of the engine 1 greatly fluctuates in the horizontal direction of FIG. 3 as indicated by an arrow A in FIG. 3, but fluctuations in the vertical direction of FIG. 3 can be suppressed. Therefore, fluctuations in the fuel consumption rate can be suppressed.

  In the control device according to the first aspect of the present invention, since the rotation speed adjustment is prohibited when the target rotation speed is set within a predetermined rotation speed range, unnecessary fluctuation of the fuel consumption rate in this case is suppressed. be able to. Therefore, the amount of fuel consumed by the engine 1 can be reduced. The controller 11 functions as the limiting means of the present invention by executing the control routine of FIG. 2 and prohibiting the rotation speed adjustment when the target rotation speed is set within a predetermined rotation speed range.

(Second form)
Next, a control device according to a second embodiment of the present invention will be described with reference to FIG. This embodiment is different in that the controller 11 executes the governor control routine shown in FIG. 4 instead of FIG. 2 of the first embodiment. In this embodiment, the controller 11 performs PID control on the difference between the actual rotational speed and the target rotational speed, and the rotational speed adjustment is performed by using the output of the PID control as a signal for controlling the operation of the actuator 12. Done. Except for these, the second embodiment has the same configuration as that of the first embodiment, and therefore, redundant description of the same configuration is omitted.

  In the second embodiment, the controller 11 has a normal PID control mode and a restricted PID control mode as control modes for controlling the operation of the actuator 12. As is well known, in the PID control, the control characteristics are changed by appropriately setting the strength of each action of the proportional action (P action), the integral action (I action), and the differential action (D action) with respect to the deviation. . In the normal PID control mode, the actions of the P operation, the I operation, and the D operation are set so that the governor device 10 responds to a disturbance that acts on the ship and varies the load of the engine 1. Note that the strength of each operation in the normal PID control mode may be set based on a well-known setting method that is generally used for a governor device for a marine engine. Is omitted.

  On the other hand, in the restricted PID control mode, the strength of the action of the I operation is set to be stronger than that of the normal PID control mode, and the strength of the action of each operation is set so that the D action hardly works. Further, the strength of the P operation is set smaller than that in the normal PID control mode. In PID control, by strengthening the action of the I operation, the control gain for high-frequency disturbances with a short period can be reduced and the control gain for low-frequency disturbances with a long period can be increased. can do. Therefore, by setting the strength of each operation in this way, in the restricted PID control mode, the response of the governor device 10 to a high-frequency disturbance having a cycle shorter than a predetermined frequency can be prohibited. As the predetermined frequency, for example, the reciprocal of the time constant T of the response from when the fuel injection amount is changed by the governor device 10 until the rotation speed of the engine 1 changes to a predetermined rotation speed determined by the changed fuel injection amount. Is set. This time constant T varies depending on the operating characteristics of the engine 1 and the operating characteristics of the actuator 12. Therefore, as a method of setting the strength of each operation in the restricted PID control mode, for example, an experiment is performed in advance using the engine 1 and the actuator 12 to which the present invention is applied, and each operation is performed based on the experimental result. Determine the strength of work. Further, for example, simulation or numerical calculation may be performed, and the strength of each operation may be determined based on the result.

  The control routine of FIG. 4 will be described. The control routine of FIG. 4 is repeatedly executed by the controller 11 at a predetermined cycle while the engine 1 is operating. In FIG. 4, the same processes as those in FIG. In the governor control routine of FIG. 4, step S21 is provided instead of step S13, and step S22 is provided instead of step S14. Therefore, when step S11 is affirmed and step S12 is affirmed, the process of step S21 is executed. In step S21, the control mode of the actuator 12 is switched to the restricted PID control mode. That is, the governor device 10 is prohibited from responding to a disturbance having a frequency higher than a predetermined frequency. Thereafter, the current control routine is terminated.

  On the other hand, if a negative determination is made in step S11, or if a negative determination is made in step S12, the process of step S22 is executed. In step S22, the control mode of the actuator 12 is switched to the normal PID control mode. Thereafter, the current control routine is terminated.

  In the second embodiment, when the target rotational speed is set within a predetermined rotational speed range, the control mode of the actuator 12 is switched to the limited PID control mode, so the governor device 10 for high-frequency disturbances higher than the predetermined frequency. Response can be prohibited. When the governor device 10 responds to such a high-frequency disturbance, the fuel injection amount is changed in a cycle shorter than the time during which the engine 1 rotates at a predetermined speed. Even if the fuel injection amount is changed in such a short cycle, the rotational speed of the engine 1 cannot follow the change in the fuel injection amount, so that the operating state of the internal combustion engine fluctuates wastefully and fuel is consumed wastefully. Is done. In this embodiment, since the response of the governor device 10 to high-frequency disturbance is prohibited, wasteful consumption of fuel can be prevented. Therefore, the amount of fuel consumed by the engine 1 can be reduced.

  Note that the method of prohibiting the response of the governor device 10 to high-frequency disturbances is not limited to a method of changing the strength of each operation of the P operation, the I operation, and the D operation. For example, when the target rotational speed is set within a predetermined rotational speed range, the output signal of the rotational speed sensor 21 is subjected to a filter that cuts fluctuations at a frequency higher than a predetermined frequency, The controller 11 controls the operation of the actuator 12 based on the output signal from which the fluctuation is cut. Even in this case, the response of the governor device 10 to a disturbance having a frequency higher than a predetermined frequency can be prohibited.

  Still another embodiment of the control device of the present invention will be described with reference to FIG. In FIG. 5, the same parts as those in FIG. In the engine 1 of FIG. 5, each cylinder is provided with an injector 30 as a fuel injection valve that controls the fuel injection into the cylinder by moving the valve body by operating or stopping the electromagnet provided therein. The point that the operation of each injector 30 is directly controlled by the engine control system 40 is different from that described above. As shown in FIG. 1, each injector 30 is connected to a common rail 31 that stores high-pressure fuel. Although not shown, the common rail 31 is supplied with fuel pumped from the fuel tank and pressurized by the high pressure pump. That is, the engine 1 in FIG. 4 is provided with a so-called common rail fuel injection system. Since this fuel injection system may be the same as a well-known common rail type fuel injection system, detailed description is omitted. The engine control system 40 is configured as a computer including a microprocessor and peripheral devices such as RAM and ROM necessary for its operation.

  Next, a method for controlling the fuel injection amount in this embodiment will be described. In this embodiment, first, the engine control system 40 acquires the operating state of the engine 1 such as the actual rotational speed based on the output signal of the rotational speed sensor 21 and the like. Next, the engine control system 40 calculates the amount of fuel to be supplied to each cylinder based on the acquired operating state of the engine 1 so that the actual rotational speed is adjusted to the target rotational speed. Thereafter, the engine control system 40 controls the operation of each injector 30 so that fuel of the fuel amount calculated at an appropriate time is injected into each cylinder. By calculating the fuel injection amount and controlling the operation of each injector 30 in this way, the engine control system 40 functions as the fuel amount calculation means, operation control means, and speed control means of the present invention.

  Also in this embodiment, the engine control system 40 repeatedly executes the governor control routine of FIG. 2 at a predetermined cycle. In this embodiment, each injector is maintained so that the fuel amount supplied from the injector 30 to each cylinder by the engine control system 40 in step S13 in FIG. 2 is maintained at the same value as the fuel amount supplied to the previous cylinder. Adjustment of the rotational speed is prohibited by controlling the operation of 30. By controlling the operation of each injector 30 in this way, the engine control system 40 functions as the limiting means of the present invention.

  As described above, even in the engine 1 equipped with the common rail fuel injection system, since the rotation speed adjustment is prohibited when the target rotation speed is set within a predetermined rotation speed range, the fuel consumption rate in this case is wasted. Variation can be suppressed. Therefore, the amount of fuel consumed by the engine 1 can be reduced.

  Further, in the engine 1 of FIG. 5, when the engine control system 40 controls the amount of fuel injected from each injector 30 by PID control, the engine control system 40 executes the control routine of FIG. The operation may be controlled. Thus, by switching the control characteristics of the fuel amount injected from each injector 30, the response of the governor device 10 to a disturbance having a frequency higher than a predetermined frequency can be prohibited. Therefore, the amount of fuel consumed by the engine 1 can be reduced.

  This invention is not limited to each form mentioned above, You may implement with a various form. For example, when the target rotational speed is set within a predetermined rotational speed range, the rotational speed adjustment by the governor device may be restricted instead of prohibiting the rotational speed adjustment by the governor device. The limitation on the rotational speed adjustment is performed by controlling the governor device so that the rotational speed adjustment is performed only when the actual rotational speed changes outside the allowable range set around the target rotational speed, for example. That is, if the rotational speed fluctuation is within an allowable range, the rotational speed adjustment is limited by allowing the fluctuation. Further, for example, when calculating the amount of fuel to be supplied to each cylinder, the difference between the fuel supply amount calculated last time and the fuel supply amount calculated this time is smaller than when there is no restriction on the rotation speed adjustment. This is done by calculating the supply amount. In this way, even if the speed adjustment by the governor device is limited, engine torque fluctuations can be suppressed, so that useless fluctuations in the fuel consumption rate can be suppressed. Therefore, the amount of fuel consumed by the engine can be reduced.

  The combustion control parameter changed by the governor device is not limited to the fuel supply amount. The present invention may be applied to, for example, an internal combustion engine including a governor device that adjusts the actual rotational speed by adjusting the amount of intake air.

  The predetermined rotation speed range is not limited to the rotation speed range set in the above-described embodiments. If the target engine speed is set low and the actual engine speed is maintained at a low engine speed, the amount of fuel to be supplied to each cylinder is small. Therefore, prohibiting the control to adjust the actual engine speed to the target engine speed prohibits the engine. The driving condition tends to become unstable. On the other hand, if the target rotational speed is set high and the actual rotational speed is maintained at a high rotational speed, the amount of fuel that must be supplied to each cylinder increases. The driving condition tends to become unstable. Therefore, the predetermined rotational speed range may be set to a rotational speed range of an operation stable region sandwiched between unstable operation regions existing in such a high rotational region and a low rotational region of the engine. Even in such a rotational speed range, the stability of engine operation can be ensured.

The figure which shows an example of the internal combustion engine in which the control apparatus which concerns on the 1st form of this invention was integrated. The flowchart which shows the governor control routine which a controller performs. The figure which shows an example of the relationship between the rotation speed and torque of the engine of FIG. 1, and a fuel consumption rate. The flowchart which shows the governor control routine which the control apparatus which concerns on the 2nd form of this invention performs. The figure which shows an example of the internal combustion engine in which the control apparatus which concerns on the other form of this invention was integrated.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 3 Fuel injection pump 10 Governor apparatus (speed control means)
11 Controller (Limiting means)
30 Injector (fuel injection valve)
40 Engine control system (fuel amount calculation means, operation control means, speed control means, limiting means)

Claims (12)

In a control method for a marine internal combustion engine comprising speed adjusting means for changing a combustion control parameter of the internal combustion engine so that the rotational speed of the internal combustion engine is adjusted to a target rotational speed,
Control of a marine internal combustion engine, wherein when the target rotational speed is set within a predetermined rotational speed range, the change of the combustion control parameter by the speed control means at the time of load fluctuation of the internal combustion engine is limited. Method.   The predetermined rotation speed range is equal to or greater than a minimum value of a target rotation speed set for the internal combustion engine during open sea voyage, and is set to prevent over-rotation of the internal combustion engine. The marine internal combustion engine control method according to claim 1, wherein a rotation speed range equal to or less than a number is set.   The change of the combustion control parameter by the speed control means when the load of the internal combustion engine fluctuates is prohibited when the target rotational speed is set within the predetermined rotational speed range. 2. A method for controlling a marine internal combustion engine according to 2.   When the target rotational speed is set within the predetermined rotational speed range, the combustion control parameter by the speed control means for a high-frequency disturbance higher than a predetermined frequency among disturbances that vary the load of the internal combustion engine. 3. The marine internal combustion engine control method according to claim 1 or 2, wherein the change is prohibited.   The predetermined frequency is set to the reciprocal of the time constant of the response from when the combustion control parameter is changed until the rotational speed of the internal combustion engine reaches a predetermined rotational speed determined according to the changed combustion control parameter. The method for controlling a marine internal combustion engine according to claim 4. In the control device for a marine internal combustion engine provided with speed adjusting means for changing the combustion control parameter of the internal combustion engine so that the rotational speed of the internal combustion engine is adjusted to the target rotational speed,
When the target rotational speed is set within a predetermined rotational speed range, it is provided with limiting means for limiting the change of the combustion control parameter by the speed control means when the load of the internal combustion engine changes. A control device for a marine internal combustion engine.   The predetermined rotation speed range is equal to or greater than a minimum value of a target rotation speed set for the internal combustion engine during open sea voyage, and is set to prevent over-rotation of the internal combustion engine. The marine internal combustion engine control device according to claim 6, wherein a rotation speed range equal to or less than the number is set.   The control device for a marine internal combustion engine according to claim 6 or 7, wherein the limiting means prohibits the change of the combustion control parameter by the speed adjusting means when the load of the internal combustion engine fluctuates.   The said restriction | limiting means prohibits the change of the said combustion control parameter by the said speed control means with respect to the high frequency disturbance higher than a predetermined frequency among the disturbances which fluctuate the load of the said internal combustion engine. A control device for a marine internal combustion engine according to claim 1.   The predetermined frequency is set to the reciprocal of the time constant of the response from when the combustion control parameter is changed until the rotational speed of the internal combustion engine reaches a predetermined rotational speed determined according to the changed combustion control parameter. The marine internal combustion engine control device according to claim 9. The internal combustion engine includes a fuel injection valve that injects fuel into a cylinder of the internal combustion engine, a fuel injection pump that supplies fuel to the fuel injection valve and can change a fuel amount to be supplied to the fuel injection valve; Further comprising
The speed control means changes the amount of fuel supplied from the fuel injection pump to the fuel injection valve so that the rotational speed of the internal combustion engine is adjusted to a target rotational speed,
The limiting means limits a change in the amount of fuel supplied from the fuel injection pump to the fuel injection valve when the target rotational speed is set within the predetermined rotational speed range. The control device for a marine internal combustion engine according to any one of Items 6 to 10. The internal combustion engine includes a fuel injection valve that injects fuel into a cylinder of the internal combustion engine, and a fuel amount calculation that calculates a fuel amount to be injected into the cylinder from the fuel injection valve based on an operating state of the internal combustion engine. Means, and operation control means for controlling the operation of the fuel injection valve so that fuel of the fuel amount calculated by the fuel amount calculating means is injected into the cylinder,
The fuel amount calculating means functions as the speed adjusting means by calculating the fuel amount so that the rotational speed of the internal combustion engine is adjusted to the target rotational speed,
The said restriction | limiting means controls operation | movement of the said fuel injection valve so that the change of the fuel quantity injected from the said fuel injection valve is restrict | limited. A control device for a marine internal combustion engine.

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