JPH0424198A - Pitch controller of variable pitch propeller - Google Patents

Abstract

PURPOSE:To secure the optimum operation constantly by obtaining the most appropriate rotational speed of an engine under existing operating condition according to engine characteristics and variable pitch propeller characteristics, and determining necessary machine speed based on the propeller characteristics and the like when determining the rotational speed. CONSTITUTION:This controller are provided with a pitch angle detecting means 1, a rotational speed detecting means 2, an air density detecting means 3, an engine output detecting means 4, and an engine load detecting means 5. The detected pitch angle, engine rotational speed, air density, and engine output are inputted to obtain machine speed by the first determining means 6 based on the variable pitch propeller characteristics. Also, the machine speed, air density, and engine load are inputted to obtain the most appropriate rotational speed under prescribed conditions at the engine load by the second determining means 7 based on engine characteristics variable pitch propeller characteristics, thus controlling the pitch of the variable pitch propeller by a pitch control means 8 so that the detected rotational speed may become the most appropriate rotational speed.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a pitch control device for a variable pitch propeller that controls the pitch of a variable pitch propeller rotated by an engine.

[Prior art]

Conventionally, as this type of device, one disclosed in Japanese Patent Application Laid-Open No. 60-76499 is known. According to this device, the propeller pitch and propeller rotation speed are adjusted to maximize propeller operating efficiency (propeller efficiency) based on data on the Matsuha number, altitude, total atmosphere, and engine shaft output during aircraft operation. ! G is in control.

[Problem to be solved by the invention]

The above-mentioned conventional devices attempt to improve the operating efficiency of the propeller in a variable pitch propeller, but the maximum thrust when the product of engine output and propeller operating efficiency is maximum, or the product of engine efficiency and propeller operating efficiency When considering the optimal state under predetermined conditions, such as the optimal fuel efficiency state where the product is maximum, even if only the operating efficiency of the propeller is optimal, this is not necessarily the operating state desired by the pilot. . In addition, an airspeed meter using a pitot tube is required to detect the Matsuha number, but this airspeed meter has many error factors and is difficult to measure accurately, so the airspeed meter was used. Control was not accurate enough. The present invention has been made to address the above problems, and
It is an object of the present invention to provide a pitch control device for a variable pitch propeller that can be operated accurately and in an optimal state under predetermined conditions at all times. Measures to solve rtlAM] In order to achieve the above object, the structural features of the present invention are as follows:
As shown in FIG. 1, a pitch control device for a variable pitch propeller that controls the pitch of a variable pitch propeller rotated by an engine includes pitch angle detection means 1 for detecting the pitch angle of the variable pitch propeller, and a pitch angle detection means 1 for detecting the pitch angle of the variable pitch propeller; a rotational speed detection means 2 for detecting the rotational speed of the engine, an air density detection means 3 for detecting the air density, an engine output detection means 4 for detecting the output direction of the engine, and an engine load detection means for detecting the load of the engine. means 5; and first deriving means 6 for inputting the detected pitch angle, the detected engine rotation speed, the detected atmospheric density, and the detected engine output to derive the aircraft speed based on the characteristics of the variable pitch propeller. ,
By inputting the derived aircraft speed, the detected atmospheric density, and the detected engine load, the optimum rotation speed under the specified conditions at the engine load is derived based on the characteristics of the engine and the characteristics of the variable pitch propeller. and a pitch control means 8 that controls the pitch of the variable pitch propeller so that the detected rotational speed becomes the optimum rotational speed.

[Intermediate layer and effects of the invention]

In the present invention configured as described above, the pitch angle detection means 1 detects the pitch angle of the variable pitch propeller, the rotation speed detection means 2 detects the rotation speed of the engine, and the atmospheric density detection means 3 detects the atmospheric density. engine output detection means 4
detects the engine output, and when the engine load detecting means 5 detects the engine load, the first deriving means 6 inputs the detected engine rotation speed, the detected atmospheric density, and the detected engine output to calculate the variable The aircraft speed is derived based on the characteristics of the pitch propeller, and the second derivation means 7 inputs the derived aircraft speed, the detected air density, and the detected engine load to determine the engine characteristics and the variable pitch propeller characteristics. Based on this, the optimum rotational speed under a predetermined condition at the engine load is derived, and the pitch control means 8 adjusts the pitch of the variable pitch propeller so that the detected rotational speed becomes the optimum rotational speed. In other words, the optimum engine speed under the specified conditions under the current operational situation is determined based on the characteristics of the engine and the characteristics of the variable pitch propeller, and the aircraft speed required to derive this speed is Since it is derived based on the characteristics of the propeller without using an air speed needle, it is possible to operate the aircraft in the optimum state under the precise predetermined conditions at all times.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 schematically shows a pitch control device for a variable pitch propeller according to the present invention applied to a single-engine airplane, and the device is composed of a variable pitch mechanism 1o, a hydraulic control circuit 20, and an electronic control device 30. There is. As shown in FIG. 3, the variable pitch mechanism 10 includes a hydraulic cylinder 11 that includes a piston lla that is movable only in the axial direction and a return spring llb, and a hydraulic cylinder 11 that is integrally movable with the piston lla of the hydraulic cylinder 11 in the axial direction. a hub 13 which is rotatably but immovably assembled in a housing 14 which is rotated by an engine (not shown) and has a cam hole 13a into which the pin 12 fits; A gear 13b integrally formed at one end of the hub 13, a gear 15a integrally formed at one end of a blade 15 rotatably but not axially movably assembled to the housing 14 and meshing with the gear 13b, etc. The hydraulic oil applied to the hydraulic cylinder 11 from the hydraulic control circuit 20 causes the piston lla to
When the blade 1 moves to the right in the figure, the blade 1 rotates in the direction of the arrow in the figure and the pitch of the blade 15 (propeller pitch)
is now changed to a higher pitch. As shown in FIG. 2, the hydraulic control circuit 20 includes an oil pump 21 driven by an engine, a regulator valve 22 that maintains a constant hydraulic pressure discharged from the oil pump 21, and a hydraulic pressure that is supplied to the hydraulic cylinder 11. It is comprised of an electromagnetic flow control valve 23 and a throttle 24 that control the flow rate of hydraulic oil. The electromagnetic flow control valve 23 is a spring center type three-boat electromagnetic valve, and controls the supply and discharge of hydraulic oil to the hydraulic cylinder 11 in accordance with the application of excitation current to each solenoid a and b by the electronic control device 30. The ports 23a connected to the hydraulic cylinder 11 are connected to the ports 23b connected to the oil pump 21 and the ports connected to the oil sump 25. When solenoid a is energized, the solenoid valve moves upward and ports 23a and 23b are communicated with each other, and when solenoid b is energized, the solenoid valve moves downward and ports 23a and 23c are communicated with each other. is configured to be Note that the throttle 24 always releases a portion (a small amount) of the hydraulic oil supplied to the hydraulic cylinder 11 to the oil reservoir 25, and the throttle 24 always releases a portion (a small amount) of the hydraulic oil supplied to the hydraulic cylinder 11 to the oil sump 25. In the event of a failure such as short-circuit or disconnection of solenoids a and b, the hydraulic oil in the hydraulic cylinder 11 is released and the pitch of the blade 15 is set to a low pitch (generally known fail-safe side for single-engine airplanes). The electronic control device 30 controls the pitch angle β of the variable pitch propeller.
a pitch angle sensor 31 that detects the atmospheric pressure P during flight, an atmospheric pressure sensor 32 that detects the atmospheric pressure P during flight, an atmospheric temperature sensor 33 that detects the atmospheric temperature T during flight, and an engine that drives the propeller of the aircraft. An engine rotation speed sensor 34 that detects the rotation speed NE, a throttle opening sensor 35 that detects the throttle opening θth that determines the load of the engine, and an intake pipe pressure sensor 36 that detects the intake pipe pressure PB of the engine. , a microcomputer 37, etc., and each sensor 31 to 36 is connected to the microcomputer 37, respectively. The microcomputer 37 includes an interface for exchanging signals with each sensor 31 to 36, a CPU for performing arithmetic processing, and a flowchart executed by the CPU.
(Refer to IF Figure 5 and Figure 7) and the map necessary for processing the program (Figure 5 and Figure 6)
(see figure), etc., and R, which allows the CPU to temporarily store variables, etc. when executing the program.
It is configured by connecting AM, etc. to a common bus. R.O.
The map stored in M is the power coefficient Cp and pitch angle β
A two-dimensional map (J(Cp,
β) MAP) (see Figure 5), and a two-dimensional map (PS (NE, PB)) which has a similar structure and shows engine output ps corresponding to engine speed NE and intake pipe pressure PB. MAP) (not shown) and a three-dimensional map (N BEST (V, ρ. θth) MAP) showing the optimum rotational speed NBEST (see Figure 6) corresponding to the aircraft speed V, atmospheric density ρ, and throttle opening θth. , and the two-dimensional map (J(Cp
. β) MAP) stores data that has been experimentally confirmed through theoretical considerations that take into account the characteristics of variable pitch propellers, and a two-dimensional map (PS (NE, PB) MA
P) stores data that has been experimentally confirmed through theoretical considerations that take engine characteristics into account, and creates a three-dimensional map (NB
EST (V, ρ, θth) MAP) stores data that has been experimentally confirmed through theoretical considerations that take into account the characteristics of the variable pitch propeller and the engine characteristics. The pitch angle sensor 31 detects the pitch angle β of the blades 15 in the variable pitch propeller, and is connected to a potentiometer 3 connected to the rotating shaft of the hub 13 shown in FIG.
1a detects the rotation angle of the hub 13, and output terminals 31b and 31c of the potentiometer 31a are connected to a slip ring (not shown) to extract a pitch angle signal representing the detected pitch angle β0. The atmospheric pressure sensor 32 detects the atmospheric pressure P around the aircraft during operation, and outputs an atmospheric pressure signal representing the detected atmospheric pressure PO. The atmospheric temperature sensor 33 detects the atmospheric temperature T around the aircraft during operation, and outputs an atmospheric temperature signal representing the detected atmospheric pressure TO. The engine rotation speed sensor 34 detects the rotation speed NE of the engine that drives the variable pitch propeller. Since a reciprocating engine is used in this embodiment, the engine rotation speed sensor 34 detects the rotation speed NE of the engine based on the ignition signal of the engine. A rotational speed signal representing the detected rotational speed NEO per unit time is output. Note that the rotational speed can also be measured optically or magnetically. The throttle opening sensor 35 detects the opening of a throttle valve in a reciprocating engine to obtain the output of the engine, and a potentiometer attached to the valve outputs an opening signal representing the detected opening θtho. The intake pipe pressure sensor 36 detects the pressure inside the intake pipe of the reciprocating engine, detects the same pressure PB, and outputs a pressure signal representing the detected intake pipe pressure PBO. Note that each of the sensors 31 to 36 outputs a detection signal of an analog value to the microcomputer 37, which converts it into a digital value at the interface of the microcomputer 37. The microcomputer 37 has each of these sensors 31
The signal line into which the detection signal outputted by ~36 is input is connected, and each solenoid a of the electromagnetic flow control valve 23,
A control signal line is connected to output a control signal indicating whether or not to apply an excitation current to b. Next, the operation of the embodiment configured as described above will be explained. When the engine is started, the microcomputer 3
In step 7, the CPU starts executing the control program shown in FIG.
A series of steps 1800 is repeatedly executed. The optimal state in this embodiment refers to a state in which maximum thrust is generated at a predetermined throttle opening, and maximum thrust control is performed for this purpose. After the initial setting process is completed, the CPU reads each detection data from the detection signals from each sensor 31 to 36 in step 1100. That is, the pitch angle βO detected by the pitch angle sensor 31 and the atmospheric pressure PO detected by the atmospheric pressure sensor 32
, the atmospheric temperature TO detected by the atmospheric temperature sensor 33, the engine speed NEO detected by the engine speed sensor 34, the throttle opening θtho detected by the throttle opening sensor 35, and the intake pipe pressure sensor 36. The intake pipe internal pressure PBO is read through the interface, and the CPU stores each data in a predetermined area of the RAM. The atmospheric pressure PO and atmospheric temperature TO were read because of the atmospheric density ρ.
This is to detect O, and after reading the atmospheric pressure PO and atmospheric temperature TO, the CPU calculates the atmospheric density ρO in step 12oO. The elements necessary for maximum thrust control in this embodiment are the aircraft speed v
O, atmospheric density ρO, and throttle opening θth. However, since the aircraft speed is not detected at this point,
Derive the aircraft speed vO. First, in step 1300, the CPU calculates the engine output PSO based on the detected engine speed NEO and the detected intake pipe internal pressure PBO using a two-dimensional map (PS (NE, PB) MAP) using the following equation. By the way, the power coefficient Cp of the propeller is Cp=PS/
(ρ ・NP-D) ... (1) However,
NP: propeller rotation speed, D= propeller diameter,
The propeller rotation speed NP is NP=to-NE...
・Since there is the relationship (2), the propeller power coefficient Cp from equations (1) and (2) is: Cp=f(PS, ρ, NE) ・・・(
3), and the CPU determines the current power coefficient C in step 14oO based on the calculated engine output PSO, the calculated atmospheric density ρ0, and the detected engine rotation speed NEO.
Calculate PO. A map of the progress rate J corresponding to the power coefficient CP and the pitch angle β is stored in the ROM, and the CPU executes step 1.
At step 500, the map is referred to using the calculated power coefficient CPO and the detected pitch angle βO, and the current rate of progress JO is read out. Between the progress rate J and the aircraft speed V, V=J-NP-D...(4)
Because of this relationship, the CPU calculates the current aircraft speed 0 from equations (2) and (4) in step 16oO based on the progress rate JO read from the map and the detected engine rotational speed NEO. From the above, aircraft speed ■0, atmospheric density ρO, and throttle opening θ
Since tho has been obtained, the CPU in step 1700 refers to the map stored in the ROM from the calculated aircraft speed vO, the calculated atmospheric density ρO, and the detected throttle opening θtho, and calculates the maximum thrust at the current throttle opening. Read out the engine rotational speed N BEST that occurs. Here, a method for creating the referenced three-dimensional map will be explained. A map (Ps(θt
h, NE) MAP) is created, and based on the detected current throttle opening θtho, the engine output is referred to to represent the relationship between the engine output and engine rotation speed at the current throttle opening θtho. Ps
- Calculate the NE line. On the other hand, since the power coefficient Cp has the relationship shown in equation (3), by substituting the detected atmospheric density ρO and the above Ps-NE line, the CP-NE line representing the relationship between the power coefficient and the engine speed can be calculated. can. On the other hand, regarding the progress rate J, since there is a relationship shown in equation (4), if we change the equation by substituting the current aircraft speed vO, we get J=f・3(NE)...(
5). Progress rate J and engine speed NE expressed by equation (5)
By substituting the calculated Cp-NE line into the relationship between the power coefficient and the progress rate, Cp-
J line can be calculated. On the other hand, a map of the thrust coefficient CT when the power coefficient Cp and the advancement rate J are specified is created, and when the relationship between the power coefficient Cp and the advancement rate J is calculated, the same thrust coefficient map (CT ( Cp, J) MAP) to calculate the CT-J line representing the relationship between the thrust coefficient and the progress rate. Regarding the progress rate J, the current aircraft speed v is calculated from equation (5). The relationship between the thrust coefficient and the engine rotation speed NE has been clarified, and the CT-NE line representing the relationship between the thrust coefficient and the engine rotation speed is calculated by substituting the above CT and -J lines into equation (5). Thrust force T is determined from thrust coefficient CT, propeller rotation speed NP, etc., as follows: T: ρ0 ・CT-NP-D...
Since it is calculated by (6), by substituting equation (2) into equation (6) and the above CT-NE line, the T-NE line representing the relationship between thrust and engine speed can be calculated. Now, it is possible to calculate the thrust that will be produced when the engine speed is changed under the current operational conditions, and the engine speed at which the same thrust is maximum (optimal speed) NBEST
The three-dimensional map described above can be created. When the maximum thrust rotation speed N BEST that produces the maximum thrust is read out in step 1700 based on the current aircraft speed Vo, atmospheric density ρO, and throttle opening θtho, the CPU executes a pitch control routine for the variable pitch propeller in step 1800. Then, in the same pitch control routine, the pitch is controlled so that the engine rotational speed NE becomes the optimum rotational speed N BEST. Specifically, the CPU reads the engine rotation speed NEO detected by the engine rotation speed sensor 34 in step 2000, and in step 2010, the CPU reads the read current engine rotation speed NEO and the optimum rotation speed calculated as described above. Compare with N BEST. Now, the current engine speed NEO is the optimal speed NBE
Suppose that it is smaller than ST. As a result of the comparison in step 2010, the CPU executes step 2020, outputting a control signal to the signal line connected to solenoid a so as not to energize the excitation current to solenoid a, and outputting a control signal to the signal line connected to solenoid a, and A control signal is output to the connected signal line to cause the excitation current to flow through the solenoid b. When solenoid b is energized, the solenoid valve moves downward in FIG. Cylinder 11 is port 2
3a to the port 23C, which communicates with the oil reservoir 25. When the hydraulic cylinder 11 communicates with the oil reservoir 25, the hydraulic oil in the cylinder 11 is discharged and the return spring 11
The piston lla moves to the left in FIG. 3 due to the pressing force b, and the blade 15 moves in the direction of the arrow shown in FIG. rotate in the opposite direction. When the blade 15 rotates in the direction of the same arrow,
Since the pitch is on the low pitch side, the horsepower absorbed by the blades 15 decreases and the engine speed increases. The routine of steps 2000, 2010, and 2020 is repeated while the engine rotational speed NEO is smaller than the optimum rotational speed N BEST, and the engine rotational speed NEO gradually approaches the optimum rotational speed N BEST. By repeating this routine several times, the engine speed NEO approaches the optimum speed N BEST,
In the end, both agree. Then, in the comparison in step 2010, the engine rotation speed NEO and the optimum rotation speed N
If it is determined that the BESTs are equal, step 2030 will be executed. In step 2030, the CPU controls both solenoids a,
A control signal is output to prevent the excitation current from flowing to the signal line connected to b. As a result, the electromagnetic valve in the electromagnetic flow control valve 23 returns to the neutral position and stops. When the solenoid valve is in the neutral position, the hydraulic oil discharged from the oil pump 21 is transferred to the port 23b of the solenoid flow control valve 23.
At the same time, the hydraulic cylinder 11 in the variable pitch propeller 10 is also shut off at the port 23a. Therefore, no more hydraulic oil flows out from the hydraulic cylinder 11 in the variable pitch propeller 10, and the piston lla in the cylinder 11 stops at its current position. however,
Strictly speaking, due to the fail-safe mechanism, a small amount of hydraulic oil flows out from the orifice 24, so the piston lla moves slightly to the left and the blade 15 rotates toward the low pitch side. When this stopped state is reached, the engine rotational speed NEO
Since the rotation speed has become the optimum rotational speed N BEST, the pitch control routine is ended and the process returns to step 1800, which is the main routine. Upon completion of step 1800, the process proceeds to step 110.
0, and the sensor 31 detects the constantly changing operational status.
to 36, and the above-described process is repeatedly executed. In the above explanation, the engine rotation speed NE is determined from the optimum rotation speed NBEST derived in steps 11oO to 1700.
Although O was smaller, the optimum rotation speed N BES
If the engine rotation speed NEO is greater than T, the following will occur. Optimal rotation speed NBEST at steps 1100-1700
After calculating, a pitch control routine is executed in step 180o, and step 201o in the pitch control routine is executed.
Engine rotation speed NEO and optimum rotation speed N BEST
When compared with the engine speed NEO, it is determined that the engine speed NEO is larger than the optimum speed NBEST, and step 204 is performed.
Execute 0. In the same step, the CPU outputs a control signal to the signal line connected to solenoid a to energize the excitation current to the solenoid a, and the signal line connected to the solenoid b to energize the excitation current to the solenoid b. Outputs a control signal that does not disturb the user. When the solenoid a is energized, the solenoid valve moves upward in FIG. 2, and the hydraulic oil discharged from the oil pump 21 is guided to the hydraulic cylinder 11 in the variable pitch propeller 10. When hydraulic oil is supplied to the hydraulic cylinder 11, the piston lla moves to the right in FIG.
The blade 15 is rotated in the direction of the arrow shown in FIG. 3 by a cam mechanism consisting of a cam hole 13a and a cam hole 13a, and a gear mechanism consisting of a gear 13b and a gear 15a. When the blade 15 rotates in the direction of the same arrow, the pitch becomes higher pitch, so the horsepower absorbed by the blade 15 increases and the engine speed decreases. By repeating this routine several times, the engine speed NEO approaches the optimum speed N BEST,
In the end, both agree. Then, in the comparison in step 2010, the engine rotation speed NEO and the optimum rotation speed N
When it is determined that the BESTs are equal, step 2030 is executed, the pitch control routine is ended, and the process returns to the main routine. In this way, if the calculated optimum engine speed N BEST is different from the current engine speed NEO, the solenoid a in the electromagnetic flow control valve 23 is changed in the pitch control routine.
, b are controlled, and the pitch of the blades 15 in the variable pitch propeller 10 is changed by hydraulic control. As a result, the engine rotation speed is controlled to approach the calculated maximum thrust rotation speed, and the maximum thrust is achieved in the operating state. can be caused to occur. In the above embodiment, the atmospheric density is calculated based on the detection results of the atmospheric pressure sensor 32 and the atmospheric temperature sensor 33, but the atmospheric density may be detected by other means. Further, when detecting the engine output and engine load, it is also possible to adopt a configuration in which other methods are used to detect the engine output and engine load. In the above example, a three-dimensional map obtained by taking into account the characteristics of the variable pitch propeller, the characteristics of the engine, etc. is referred to, based on the throttle opening θth, atmospheric density ρ, and aircraft speed V, which vary depending on the operational status. The engine speed that produces the maximum thrust is derived from the same three-dimensional map, but in order to reduce the storage capacity of the three-dimensional map, the two-dimensional map is
It is also possible to use a configuration in which one is used. For example, after creating a three-dimensional map, a first two-dimensional map KP (V
, ρ) A second MAP is created, and the optimum rotational speed NBEST is read from the argument KP and the throttle opening θth read from the first two-dimensional map.
Two-dimensional map NPW (KP, θLh)! 'IA
Create P. Then, instead of referring to the three-dimensional map in step 1700, in step 1710, the aircraft speed V and the atmospheric density ρ are
The argument KP is read out by referring to the first two-dimensional map KP (V. ρ) MAP, and from the argument KP and the throttle opening degree 8th read from the same two-dimensional map in step 1720. Second two-dimensional map NPii (KP, θth) MAP
The optimal rotation speed N BEST is read by referring to . In the embodiments described above, the optimum state is the state in which the maximum thrust is generated, but it is also possible to perform the optimum fuel efficiency control in other states, for example, the state in which the aircraft operates at the optimum fuel efficiency. Even in this optimal fuel efficiency control routine, aircraft speed vO and atmospheric density ρO
The procedure for creating this three-dimensional map will be explained in order to read out the engine rotational speed N BEST that provides the optimum fuel efficiency at the current throttle opening by referring to the map from the current throttle opening and the throttle opening θtho. J = f3 (NE) derived when obtaining the maximum thrust rotation speed (5)
It is assumed that the Cp-J line representing the relationship between the power coefficient and the progress rate has been calculated. As a map, a map (ηP
(Cp, J) MAP), and throttle opening θ
A map (ηE (θth. NE) MAP) showing the engine efficiency ηE when th and the engine speed NE are specified is created in advance. First, the Cp-J line representing the relationship between the power coefficient and the rate of progress, and the map of propeller efficiency ηP (ηP(Cp, J
) MAP ) is used to calculate the ηP-J line representing the relationship between propeller efficiency ηP and progress rate J. This ηP
- Substituting equation (5) into the J line and deleting the progress rate, we get
The ηP-NE line representing the relationship between propeller efficiency ηP and engine speed NE can be calculated. Next, based on the detected throttle opening θthO,
By referring only to the necessary part of the map of engine efficiency ηE (ηE(θth. NE) NAP), we can obtain ηE-, which represents the relationship between engine efficiency ηE and engine speed NE.
The NE line can be derived. Product of propeller efficiency ηP and engine efficiency ηE (total efficiency η
The optimal fuel efficiency is achieved when T (=ηP×ηE)) is maximum, so from the ηP-NE line and the ηE-NE line, the ηT-NE line, which represents the relationship between the overall efficiency and the engine speed NE, can be obtained. It can be derived. A three-dimensional map is created by setting the engine rotation speed NE at which the overall efficiency is maximum on this ηT-NE line as the optimum rotation speed NBEST. In actual control, the CPU refers to the three-dimensional map of the optimal fuel efficiency created in this way in step 1730 instead of step 1700, and determines the optimal rotation speed N that will give the same optimal fuel efficiency.
Once the BEST is obtained, a pitch control routine is executed in step 1800 to control the pitch of the variable pitch propeller so that the engine rotational speed NE becomes the optimum rotational speed BEST. As a result, if the current engine rotation speed NEO is smaller than the optimum rotation speed N BEST, in step 2020, the pitch is set to a low pitch in order to reduce the suction horsepower in the variable pitch propeller 10, and the engine rotation speed NEO is increased; If the current engine rotational speed NEO is smaller than the optimum rotational speed N BEST, in step 2040, the pitch is set to a high pitch and the engine rotational speed NEO is decreased in order to increase the suction horsepower in the variable pitch propeller 1o. By either control, the engine rotational speed NEO matches the target engine rotational speed OB, and it is possible to operate the vehicle with optimal fuel efficiency. In addition, if the configuration is such that the two maps can be switched by operating a select switch provided in the cockpit and selectively perform maximum thrust control and optimal fuel efficiency control, appropriate control can be performed depending on the situation. It also improves maneuverability. Of course, other calculation methods are also possible for the calculation procedure for obtaining the rotation speed that provides the maximum thrust and the rotation speed that provides the optimum fuel efficiency.

[Brief explanation of drawings]

FIG. 1 is a claim correspondence diagram corresponding to the structure of the present invention described in the above claims, FIG. 2 is a schematic diagram of a single-engine airplane, and FIG. 3 is a sectional view of a main part of a pitch variation mechanism in a variable pitch propeller. Figure 4 is a flowchart corresponding to the main routine of the control program, Figure 15 is a map of the rate of advance corresponding to the power coefficient and pitch angle β, and Figure 96 is the maximum map corresponding to aircraft speed, atmospheric density, and throttle opening. FIG. 7, which is a diagram showing a map of the thrust rotation speed, is a flowchart corresponding to the pitch control routine of the control program. Explanation of symbols 10...Variable pitch mechanism, 20...Hydraulic pressure! ′! I control circuit, 30... Electronic control unit, 31-36... Sensor, 37... Microcomputer, β0... Pitch angle, PBO... Suction pipe internal pressure, ■0... Machine speed, ρO
...Atmospheric density, θthO...Throttle opening,
NEO: Engine rotation speed. N BEST...Optimal rotation speed. Applicant Toyota Motor Corporation Representative Patent Attorney Teru Hase (1 other person)

Claims (1)

[Scope of Claims] A pitch control device for a variable pitch propeller that controls the pitch of a variable pitch propeller rotated by an engine, comprising: pitch angle detection means for detecting a pitch angle of the variable pitch propeller; and a rotational speed of the engine. an air density detection means for detecting air density; an engine output detection means for detecting the output of the engine; an engine load detection means for detecting the load of the engine; and the detected pitch angle. and a first deriving means for inputting the detected engine rotational speed, the detected air density, and the detected engine output, and derives an aircraft speed based on the characteristics of the variable pitch propeller; and the derived aircraft speed and the detected atmospheric air. a second deriving means inputting the density and the detected engine load and deriving the optimum rotation speed under predetermined conditions at the engine load based on the characteristics of the engine and the characteristics of the variable pitch propeller; A pitch control device for a variable pitch propeller, comprising pitch control means for controlling the pitch of the variable pitch propeller so that the detected engine rotation speed becomes the optimum rotation speed.