JPS582876B2 - Kahenpitsuchi Propeller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a power engine with a variable pitch propeller used for ships or, rarely, for land use.

Among the systems conventionally used as control devices for motive engines with variable pitch propellers, the following three types are known as representative ones.

That is, (1) a method in which the engine output torque is kept constant and the propeller pitch angle is controlled by the governor so as to obtain the desired rotation speed; (2) the engine rotation speed is kept constant by the governor; (3) A method in which the propeller pitch angle is arbitrarily controlled from the outside; and (3) a method in which both of the above methods are used in combination by utilizing the characteristics for each load range.

Method (1) is also called load control for variable pitch propellers, and even if it is not specifically called load control, if an overload (overpitch) prevention device is installed, if that device is activated. As is clear from the fact that it is virtually the same as method (1), or shows a similar effect, the engine's full output is always maintained regardless of changes in external conditions such as the hull, water, weather, wind direction, etc. It has the advantage of being able to safely reach its maximum potential, but has disadvantages such as being unstable under low loads and not being able to switch forward or backward.

Therefore, method (1) is suitable for continuous navigation in a high load area.

On the other hand, the method (2) directly manipulates the pinch angle, so it is not only possible to switch forward and backward but also to freely adapt from low loads to high loads, and is currently widely used.

However, with method (2), there is a risk of accidentally overshooting during operation, so care must be taken when the load is high.

Method (3) takes advantage of the fact that (1) is suitable for high loads and (2) is suitable for low loads and forward/reverse switching.
2) This is a method in which both methods are used together, and this is automatically or semi-automatically switched programmatically from (1) to (2), or vice versa, in response to changes in the load range.

However, in the above methods (1) and (3), a propeller speed governor was required to control the propeller pitch angle. ), or at least to prevent and suppress the overspeed of the driving engine itself, each driving engine must have one speed governor, so in the conventional system, the speed governor A total of at least two is required.

Of these, there is no problem since the speed governor for the driving engine is always attached to the original as mentioned above, but installing a new propeller speed governor not only increases the cost itself, but also For example, there is a concept that it is unnecessary in at least (2) of the widely used methods (1) and (2) above, and as a practical matter, the variable pitch control box and main shaft of a variable pitch propeller are considered unnecessary. It is by no means easy to install a governor or its drive device that is different from the structure in the vicinity, so although the excellent effects of installing a propeller governor can be fully expected, Implementation of this was difficult to achieve.

Furthermore, despite the above-mentioned problems, even if two speed governors are installed, a certain difference in characteristics must be established between the two speed governors. The difficult problem remains that it must be set correctly and maintained correctly over long periods of use.

Therefore, the development of new technology to solve all these problems related to the control system of a power engine with a variable pitch propeller and to realize simplification as well as improvement of control performance is necessary.
This has been a long-awaited goal of those skilled in the art.

In order to meet the above-mentioned needs, this invention makes more effective use of one speed governor attached to the engine, and by specifically providing a conventional propeller speed governor and providing a total of two speed governors. , the aim is to realize a control device that can achieve the same effect as was achieved for the first time.

Another object of the present invention is to eliminate the difficulty of maintaining a predetermined characteristic difference in governor characteristics when two governors are used together by using one governor. The objective is to eliminate the problem.

To achieve these objects, the gist of the present invention is to have one speed governor driven at a speed proportional to the main shaft speed, and a power piston built in the speed governor that drives the entire drive engine. Elasticity that allows the piston to move beyond the position corresponding to the fuel injection amount under load in the direction of increasing the injection amount, as well as to realize a smaller fuel injection amount than the position corresponding to the power piston position due to external force. A fuel injection amount adjustment rod in which a mechanism is interposed between the two, a fuel injection amount limiter that mechanically limits movement of the fuel injection amount adjustment rod in the direction of increasing the injection amount, and the fuel injection amount limiter. an overtorque detection mechanism that detects a value proportional to the amount of displacement caused in the elastic mechanism due to mechanical limitations, and a pitch angle setting value of the variable pitch propeller proportional to the value detected by the overtorque detection mechanism. When the fuel injection amount limiter does not limit the fuel injection amount, the main shaft speed is controlled by the speed governor to the driving engine under direct external control of the propeller pitch angle. By increasing or decreasing the fuel injection amount according to the load, it is controlled to a value equivalent to the speed setting of the speed governor.
When the fuel injection amount limiter limits the fuel injection amount,
The main shaft speed is controlled to a value equivalent to the governor's speed setting by increasing or decreasing the propeller pitch angle according to the load using an overtorque detection mechanism based on the driving engine output torque corresponding to the limited fuel injection amount. The present invention relates to a control device for a power engine with a variable pitch propeller.

The power engine referred to here is a general term for diesel engines, steam turbines, gas turbines, etc., and includes those that can adjust the output torque at a certain rotation speed, but below we will mainly use diesel engines as an example and abbreviate them as engines. explain.

Further, a variable pitch propeller is a general term for a propeller whose absorbed torque changes due to the geometric movement of its blades, and is hereinafter abbreviated as a propeller.

The configuration of the present invention will be explained with reference to the drawings.
The figure is an explanatory diagram showing one embodiment of the device of the present invention,
The engine 1 drives a propeller 3 via a main shaft 2.

The pitch angle of the propeller 3 can be adjusted steplessly by the servo mechanism inside the control box 5 by moving the lever 4 from full AH (forward) to full N (neutral) to full As (reverse). Set.

The engine 1 has a speed governor 6, and its speed is set via a speed signal line 1 from a transmitter 14 in a remote control stand 13.
5 and is transmitted to the speed governor 6.

Further, 9 is a spring cylinder used as an embodiment of an elastic mechanism interposed between the fuel injection amount adjustment rod 10 and a power piston (not shown) built in the speed governor 6. Movement is lever 7, lever 8, spring tube 9
Then, the fuel injection amount adjustment rod 10 is moved to adjust the injection amount of the fuel injection pump 11 to control the output torque generated by the engine.

The + arrow in the figure indicates the direction in which the fuel injection amount increases.

As is well known, the power piston in the speed governor 6 includes the entire stroke from the zero fuel injection position to the full load injection position. The levers 7 and 8 are arranged so as to provide a margin for the stroke in the increasing direction.

The spring cylinder 9 has a spring set therein with a force sufficient to move the fuel injection amount adjustment rod 10, and the speed governor 6 moves the fuel injection amount adjustment rod 10 via the lever 7 and the lever 8. When moving, the spring cylinder 9 faithfully transmits the movement as if it were an integral link, but if a force is applied to the fuel injection amount adjustment rod 10 itself from the outside in the direction of decreasing the fuel injection amount, the internal The spring is compressed and therefore the spring tube 9 as a link
is increased in length to allow a lower fuel injection amount than that corresponding to the position of the power piston in the governor 6 and the levers 7 and 8 connected thereto.

Such a spring cylinder or similar elastic mechanism is commonly installed in any engine in order to counteract the action of the speed governor 6 and shut off and stop the engine's fuel injection.

The fuel injection amount limiter 12 mechanically restricts the movement of the fuel injection amount adjustment rod 10 in the direction of the cross arrow beyond a certain value, and limits the output torque generated by the engine 1.

Depending on the required specifications, this limit position may be adjusted with a screw and then fixed, or as shown in the figure, the torque limit signal line 1 is connected to the transmitter 16 in the remote control stand 13.
It can also be made variable remotely via step 7.

The fuel injection amount adjustment rod 10 is connected to this fuel injection amount limiter 12.
Unless it hits, it will be controlled by the speed governor 6, but if it does, the fuel injection amount limiter 12 will be at the limiting position regardless of the position of the power piston of the speed governor 6.

In other words, the fuel injection amount or generated output torque of the engine 1 is determined according to a value controlled by the speed governor 6 or a value limited by the fuel injection amount limiter 12, whichever is smaller.

The overtorque detection mechanism is the core of the present invention, and functions to detect the amount of elongation of the spring tube 9 that occurs as a result when the fuel injection amount adjustment rod 10 hits the fuel injection amount limiter 12. In the figure, it is represented by a lever 18 and a detector 19.

The upper end of the lever 18 is connected to the upper extension of the lever 8 and the link 31.
connected by

Further, the lower end of the lever 18 is connected to the fuel injection amount adjusting rod 10 with a bottle.

Therefore, the position of the pin 20 in the center of the lever 18 is such that the fuel injection amount adjustment rod 10 does not touch the fuel injection amount limiter 12, so that the spring tube 9 does not extend and remains integral. When the lever 10 moves as instructed by the speed governor 6, the upper and lower ends of the lever 18 move in opposite directions and remain stationary.

However, when the spring tube 9 extends, the lower end of the lever 18 will move to the right in the figure according to the amount by which the spring tube 9 has expanded, even if the upper end does not move. The upper end of both will move to the right in the figure, so pin 20
The position of moves to the right.

The detector 19 detects this as an overtorque amount.

This detected overtorque amount is purely due to the mechanical restriction of the fuel injection amount limiter 12 as described above.
This relates only to the amount by which the fuel injection amount limiter 12 has expanded, and refers to the surrounding circumstances where the expansion occurred, i.e. to what limiting position the fuel injection amount limiter 12 is set, and therefore to what position the fuel adjustment rod 1 is set.
0 hits the fuel injection amount limiter 12 or not.

For this reason, the governor 6 is designed so that the fuel injection amount of the engine 1, that is, the resulting output torque generated by the engine, is as large as necessary to maintain the rotational speed corresponding to the speed setting of the governor 6. As long as the power piston is controlled as instructed by the power piston, that is, if the spring tube 9 does not extend, the position of the pin 20 is constant and immovable, and the detector 19 does not detect overtorque.

However, regardless of the value of the fuel injection amount, that is, the engine-generated output torque, if that value is limited to a certain value by the fuel injection amount limiter 12, and as a result, the spring tube 9 expands, this will cause the governor 6 to elongate. This means that the fuel injection amount, that is, the engine generated output torque, is not enough to maintain the rotational speed corresponding to the speed setting, and the engine is in a so-called overtorque state.

In this case, engine-generated output torque sufficient to maintain the specified rotational speed cannot be obtained, so if the pitch angle of the propeller 3 does not change, the actual rotational speed will fall below the value equivalent to the speed setting of the governor 6. When the load torque of the propeller 3 decreases to the point where it becomes equal to the limited engine-generated output torque, equilibrium is reached for the first time.

Therefore, the engine 1 is operated at a rotation speed smaller than the speed setting value given to the speed governor 6 by overtorque, so the power piston of the speed governor 6 increases the fuel injection amount to regulate the rotation speed. Attempt to restore the value.

However, the movement of the power piston simply extends the spring cylinder 9 further, moves the upper end of the lever 18 to the right in the figure, and therefore also moves the pin 20 to the right, causing the detector 19 to detect overtorque. becomes.

In the embodiment shown in FIG.
It is represented by a lever 25 and a receiver 26.

The pitch angle of the propeller 3 is determined from the transmitter 28 of the remote control stand 13 to the pitch signal line 21, to the receiver 22, to the lever 2.
It is transmitted in the order of 3, and the lever 4 of the control box 5 is
As already mentioned, the lever 23 has a pin 24 that can slide in its longitudinal groove, and the lever 25 has a pin 24 at its lower end. 24 and receives a command from the overtorque detector 19, the receiver 26 makes a pendulum movement about its fulcrum.

Now, as already mentioned, the pin 20 occupies a fixed position while the spring tube 9 is not extended, and when the spring tube 9 is extended due to overtorque, it moves to the right in the figure accordingly. Movement of the pin 20 in the right direction is detected by the overtorque signal line 27 from the detector 19 to the receiver 2.
6, which causes the lever 25 to similarly swing to the right.

Therefore, when not in the overtorque state, the lever 25 and the pin 24 are fully swung to the left in the figure, and the lever 23 is operated to control the oscillator 28 and the pill signal line at a lever ratio corresponding to the position of the pin 24 at this time. 21 and a receiver 22, the pitch angle operation amount is transmitted to the lever 4 to change the pitch angle.

This is assumed to be +1 normal pitch angle transmission. However, when overtorque occurs, the pin 24 moves to the right according to the amount of overtorque, so the lever ratio of the lever 23 becomes smaller, reducing the incoming pitch angle operation amount and transmitting it to the lever 4.

In other words, the larger the amount of overtorque, the more
In both the H case and the AS case, the degree to which the pitch angle is reduced in the N direction becomes stronger.

If the pin 24 moves extremely to the right, the lever 4 will have a value almost close to N, regardless of the amount of pitch angle operation that arrives.

From the remote control stand 13, a speed signal line 15, a torque limit signal line 17, and a pitch signal line 21 are led out from transmitters 14, 16, and 28, respectively, and the transmission means used for these are mechanical,
There are electrical methods, and methods using fluid media such as air and pressure oil.

Now, the speed signal line 15 controls the speed setting level of the speed governor 6.

The torque limit signal line 17 is connected to the fuel injection amount limiter 12.
By controlling the position of the fuel injection amount adjustment rod 10
However, this limit value is generally between high and medium loads, and is not limited to low loads.

Further, the pitch signal line 21 is connected to a receiver 22 and a lever 23.
The pitch angle of the propeller 3 is controlled through.

It is convenient that the combination of control values of these three signal lines is adapted to the characteristics of the ship and engine, programmed, and operated all at once.

In other words, FIG. 1 shows a control lever 29 that allows the cams to be moved all at once and the transmitters 14, 16, and 28 to be operated programmatically. By providing a lever 30 to displace the cam in the axial direction, the program can be modified to accommodate changes in characteristics, the arrangement of which is shown in FIG.

If the engine 1 drives an alternator as well as the propeller 3 at the same time, it is necessary to keep the rotational speed constant regardless of the propeller load (and therefore the ship's speed). Since a speed remote control is not required, the speed signal line can be omitted.

Further, the limit value of the fuel injection amount limiter 12 may only be fixed at one point near the full load fuel injection amount, and variable control may not be necessary, but in this case, the torque limit signal line is omitted.

FIG. 2 is a program diagram showing an example of a program with three signal lines in a general case.

In the figure, the horizontal axis is the position of the control lever 29, from N (neutral) to AH (forward) in the (+) direction and As in the (-) direction.
(reverse), and the signal shown by the solid line is programmed according to that position.

The numbers in the figure indicate the same parts as the symbols in Figure 1,
There is always a way to understand.

From bottom to top in FIG. 2, the speed setting of the governor 6, the limit amount of the fuel injection amount limiter 12, and the receiver 22
The pitch angle signal program is shown below.

As shown in this figure, the maximum value of the speed setting of the speed governor 6 is either the same as the full speed (rated rotational speed) of the engine, or
Alternatively, only S1 can be made slightly higher.

The limit amount of the fuel injection amount limiter 12 is the same when the engine 1 is at the programmed rotational speed (solid line 6 at the bottom of the diagram) at low load (in the range of +4 to -4 on the scale of the control lever 29 in the figure). Programmed propeller pitch (solid line 2 above diagram)
2), so that more fuel is injected by S2 than the position of the fuel injection amount adjustment rod 10 corresponding to the load (dotted line 10 in the center of the figure) corresponding to the load when the control lever 2 is operated, and the control lever 2
9, the maximum scale 6 and -6 positions are set to the full load position.

Also, the pitch angle (solid line 22) is neutral at the N point of the control lever 29, and at scales 6 and -6, it is based on the rotational speed programmed for the engine 1 at that scale (solid line 6 at the bottom of the figure). Similarly, when operating at the full fuel injection amount at the programmed fuel injection amount limit position (solid line 12 in the center of the figure), the pitch angle is set to be 83 times larger than the generally compatible pitch angle.

The height and slope of these lines can be adjusted as necessary using the co-pilot lever 30.
It may be corrected by

Now, in the operating state, turn the control lever 29 in Fig. 2 from -4 to +.
4, the speed governor 6 attempts to control the fuel injection amount so that the engine 1 rotates at a medium to low speed corresponding to the position of the control lever 29.

On the other hand, since the propeller pitch angle received by the receiver 22 is a so-called low pitch centered on N, the fuel injection amount controlled by the governor 6 is controlled by the second It is sufficiently low as shown by the chain line in the center of the figure.
There is a margin of S2 up to the limit position of the fuel injection amount limiter 12.

Therefore, as is clear from FIG. 1, the fuel injection amount adjustment rod 10 does not hit the fuel injection amount limiter 12.
Regardless of this, the spring tube 9 remains integral with the lever 7.
, and move as controlled by the speed governor 6 through the lever 8.

This is shown in the center of FIG. 2 by a dotted line 10 representing the actual movement of the fuel injection amount adjusting rod 10 running along a chain line 6 representing the movement of the speed governor 6.

Again, in FIG. 1, since the spring tube 9 is not extended as a unit, it is not in an overtorque state, but the pin 20 on the lever 18 is in a fully swung state to the left in the figure, and its movement is Detector 19, overtorque signal line 2
7. Since the pin 24 is pushed to the left in the figure via the receiver 26 and the lever 25, the movement of the pitch receiver 22 is normally transmitted to the lever 4, and the actual pitch angle is as shown in Figure 2. The value is along the line of the receiver 22 as shown by the upper dotted line 4.

Therefore, when this control lever 29 is placed in the scale range from -4 to +4, the actual pitch angle of the propeller 3 will be between (medium pitch AH) (medium pitch AH) (N) (medium pitch As). engine 1 or main shaft 2.
The actual rotational speed of the engine is also maintained at the programmed value by controlling the fuel injection amount so that the speed governor 6 follows the given speed setting.

Therefore, in this state, the fuel injection amount limiter 12 does not limit the fuel injection amount, so the engine or main shaft speed is controlled by the governor 6 under direct external control of the propeller pitch angle.
is a state in which the fuel injection amount of the engine 1 is increased or decreased according to the load and controlled to a value corresponding to the speed setting given to the speed governor 6.

In other words, since the above method (2) keeps the rotational speed of the engine constant by the speed governor and arbitrarily manipulates the propeller pitch angle, AH (advance) and As ( This means that operations such as reversing can be performed directly on the vehicle itself.

Next, in Fig. 2, move the control lever 29 from +4 to +6.
Consider the case where the scale range is advanced to .

(In the case of changing from -4 to -6, the pitch angle is the same and the direction is the As direction, and the other things are the same, so we will omit it.) The governor 6 controls the engine 1 with the control lever. Attempts are made to increase the fuel injection amount to reach high speed rotation corresponding to position 29, but since the propeller pitch angle received by receiver 22 is large, under such high speed rotation, the chain line 6 in the center of the figure The rotational speed corresponding to the predetermined speed setting cannot be maintained unless a large amount of fuel is injected as shown in FIG.

However, since the fuel injection amount limiter 12 limits the injection amount according to the program, the actual fuel injection amount is suppressed to the dotted line 10, which is S4 less than the dashed line 6 indicated by the speed governor, and the rotation speed is reduced. Cannot maintain program value.

This is an overtorque state, and the difference S4 in the injection amount is the difference in movement between the power piston of the governor 6, which limits the fuel injection amount of the fuel injection amount limiter 12, and the fuel injection amount adjustment rod 10. This difference is allowed by the expansion of the spring tube 9.

The amount of extension of the spring tube 9 is detected by the detector 19 when the pin 20 of the lever 18, which is an overtorque detection mechanism, moves to the right in FIG. Then, the lever 25 is swung to the right, and the pin 24 is also moved to the right.

Then, the pitch angle given to the receiver 22 according to the program moves the lever 4 in a direction approaching N as the pin 24 moves, thereby reducing overtorque.

This reduction is shown at the top of FIG. 2 as the actual pitch angle for program 22 by dotted line 4, which reduces the pitch angle by S3.

The amount of decrease S3 in the pitch angle is proportional to the overtorque S4 detected by the amount of extension of the spring cylinder 9.

The fuel injection amount of the engine 1, that is, the generated output torque, is maintained at a constant value according to the position of the control lever 29 by the fuel injection amount limiter 12, and the actual pitch angle is adjusted to S3 so that the overtorque is reduced when an overtorque condition occurs. only reduced.

In other words, the actual pitch angle is the value that reduces overtorque.
In other words, the programmed fuel injection amount approaches a value that allows the programmed rotational speed to be maintained.
The power piston of the speed governor 6 causes the spring cylinder 9 to extend as a margin stroke further in the direction of increasing the fuel injection amount from the full load injection position.

In this way, the actual pitch angle is automatically reduced by the extension of the spring tube 9, but the amount of reduction S3 changes depending on the degree of ship operating conditions such as sea level, swamping, and wind direction.

Note that the speed governor 6 has a speed droop (also called a static speed fluctuation rate or speed regulation rate, which is an essentially known property in which the position of the power piston moves in proportion to the decrease in rotational speed). , a residual speed deviation S1 proportional to the amount of reduced S3 remains, but this can be anticipated in advance in the program, and it can be corrected using the co-pilot lever 30 if the forecast changes.

Therefore, in this state, the fuel injection amount limiter 12 limits the fuel injection amount, so the engine or main shaft speed is controlled by the overtorque detection mechanism, which adjusts the propeller pitch angle based on the engine output according to the limited fuel injection amount. This is a state in which the speed is controlled to a value corresponding to the speed setting given to the speed governor, increasing or decreasing depending on the load.

In other words, it is the method (1) of the prior art described above, in which the engine output torque is kept constant and the propeller pitch angle is controlled by the governor so as to obtain the desired rotational speed. The full or desired output of the engine can always be safely and automatically drawn out regardless of changes in the hull, water, weather, wind direction, etc.

In the above description, the case where one engine drives one propeller has been shown, but of course it also applies to a so-called multiple engine arrangement in which two or more engines drive a common propeller at the same time.

For example, in the case of a known parent-child governor system, the parent governor may be replaced with the governor 6 in this description.

In the case of various other systems, the governor, which is the standard for fuel injection amount control for each engine, is
By successively connecting the related devices disclosed in this description, it is possible to embody the concept of the control device of the present invention very easily.

As described above, the present invention uses only one speed governor to maintain a constant engine output torque under high load, which was previously impossible to achieve without using at least two speed governors. keep,
One method is to use a governor to control the propeller pitch angle so as to obtain the desired rotation speed, and the other is to use a governor to keep the engine rotation speed constant during low loads, and then adjust the propeller pitch angle directly from the outside. There are two methods that can be operated: forward and backward switching and low-load stable cruising, and switching between the two methods is simply done by the fuel injection amount adjustment rod hitting the fuel injection amount limiter at any position. This makes it easy and smooth to operate, and it has a structure that allows easy programmatic control using a single control lever. Not only can it achieve exactly the same performance as a system using multiple speed governors, but since each speed governor does not have a special structure, it can be used to replace the speed governor installed in conventional engines. It can be used as is, and since there is only one speed governor,
Unlike the case of two governors, it is not possible to maintain the adjustment of the characteristic difference between the governors, and there is no deterioration in maneuverability due to the collapse of the characteristic difference, and in addition, the propeller, which has traditionally been avoided due to the difficulty of installation. The problem of the speed governor is also solved, and it is simple, inexpensive, and has great performance effects.

Note that the overtorque detection mechanism, pitch correction mechanism, and related parts are shown as lever links in this explanation to make it easier to understand, but the same effect can be obtained even if they are replaced with a comprehensive electronic system. Not even.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the device of the present invention, and FIG.
The figure is a program diagram of the device. 1... Engine, 2... Main shaft, 3... Variable pitch latch,
4... Lever, 5... Control box, 6... Speed governor, 7, 8...
Lever, 9...Spring cylinder, 10...Fuel injection amount adjustment rod, 11
...Fuel injection pump, 12...Fuel injection amount limiter, 1
3... Remote control stand, 14... Transmitter, 15... Speed signal line, 16... Transmitter, 17... Torque limit signal line, 18... Lever, 19... Detector, 20... Pin, 21 ... Pitch signal line, 22 ... Receiver, 23
... Lever, 24 ... Pin, 25 ... Lever, 26 ... Receiver, 27 ... Overtorque signal line, 28 ... Transmitter, 29 ... Control lever, 30 ... Co-pilot lever, 31 ... Link .

Claims (1)

[Claims] 1 One speed governor is driven at a speed proportional to the rotational speed of the main shaft, and the power piston of the speed governor moves beyond the position corresponding to the fuel injection amount at full load of the power engine, and further increases the injection amount. A fuel injection amount adjustment rod that is connected in a relationship that allows it to move in a direction, and has an elastic mechanism interposed in the connection so that an external force can realize a smaller fuel injection amount than the position of the power piston. , a fuel injection amount limiter that mechanically limits the movement of the fuel injection amount adjustment rod in the direction of increasing the injection amount, and a displacement amount caused in the elastic mechanism due to the mechanical restriction by the fuel injection amount limiter. It is characterized by having an overtorque detection mechanism that detects a proportional value, and a pitch correction mechanism that proportionally decreases the pitch angle set value from the outside of the variable pitch propeller in response to the value detected by the overtorque detection mechanism. A control device for a power engine with a variable pitch propeller.