JPH048697A - Pitch controller of variable pitch propeller - Google Patents

Abstract

PURPOSE:To constantly generate the maximum thrust at the throttle rate controlled by a pilot so as to enhance controllability by controlling the pitch of a variable pitch propeller so that a detected engine speed equals the maximum thrust speed. CONSTITUTION:Detection signals output by sensors 31 to 35 are input to a microcomputer 36 and a control signal indicating whether or not an exciting current is passed through each of the solenoids (a), (b) of a solenoid flow rate control valve 23 is output to the microcomputer 36. When an engine is started the CPU of the microcomputer 36 reads an engine speed NEO detected by the engine speed sensor 34, and when the engine speed is different from the maximum thrust speed calculated, controls the solenoids (a), (b) of the solenoid flow rate control valve 23 within a pitch control routine and varies the pitch of the blade 15 of a variable pitch propeller 10 by means of hydraulic control. As a result, the engine speed is so controlled as to approximate the maximum thrust speed and the maximum thrust can be generated during navigation.

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 Publication No. 60-76499 is known. According to the device, based on data on the Matsuha number, altitude, total atmospheric temperature, and engine shaft output while the aircraft is in operation,
The propeller pitch and propeller rotation speed are controlled to maximize propeller operating efficiency (propeller efficiency).

[Problem to be solved by the invention]

The conventional device described above attempts to improve the operational efficiency of the propeller based only on the performance data of the variable pitch propeller, and does not take into account the characteristics of the engine. Since engine characteristics are reflected in engine output, considering the thrust expressed as the product of engine output and propeller operating efficiency,
When a pilot operates a throttle at a certain opening, even if the propeller operating efficiency is maximized under the operating conditions at that time, the maximum thrust at that throttle opening is not necessarily generated. 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 generate maximum thrust at the throttle opening operated by a pilot and improve maneuverability.

[Means to solve the problem]

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 momentum detection means 1 for detecting aircraft speed and atmospheric density detection means for detecting atmospheric density. means 2, throttle opening detection means 3 for detecting the throttle opening, the detected aircraft speed, the detected atmospheric density, and the detected throttle opening are input, and the characteristics of the engine and the characteristics of the variable pitch propeller are inputted. a maximum thrust rotation speed detection means 4 for determining the maximum thrust rotation speed of the engine that produces the maximum thrust at the throttle opening based on the rotation speed; a rotation speed detection means 5 for detecting the rotation speed of the engine; and pitch control means 6 for controlling the pitch of the variable pitch propeller so that the rotational speed of the variable pitch propeller reaches the maximum thrust rotation speed.

[Operation and effects of the invention]

In the present invention configured as described above, in the pitch control device for a variable pitch propeller that controls the pitch of a variable pitch propeller rotated by an engine, the momentum detection means 1 detects the aircraft speed, and the air density detection means 2 detects the atmospheric density, and when the throttle opening detection means 3 detects the throttle opening, the maximum thrust rotation speed detection means 4 inputs the detected aircraft speed, the detected atmospheric density, and the detected throttle opening. The slot is based on the characteristics of the engine and the characteristics of the variable pitch propeller. The maximum thrust rotation speed of the engine that produces the maximum thrust at the torque opening is determined, and the rotation speed detection means 5 detects the rotation speed of the engine, so the pitch control means 6 determines whether the detected rotation speed is the maximum thrust rotation speed. The pitch of the variable pitch propeller is controlled so that That is, the engine rotation speed (maximum thrust rotation speed) that produces the maximum thrust at the current throttle opening is determined based on the engine characteristics and the characteristics of the variable pitch propeller, and the engine rotation speed is determined by changing the pitch of the variable pitch propeller. Since the number of rotations is set to the maximum thrust rotation speed, it is possible to always generate the maximum thrust at the throttle opening operated by the pilot, and maneuverability is improved.

【Example】

Hereinafter, one embodiment of the present invention will be described 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 has a variable pitch mechanism. 10, a hydraulic control circuit 20, and an electronic control device 3o. As shown in FIG. 3, the variable pitch mechanism 10 is integrated with a hydraulic cylinder 11 including a piston 11a and a J turn spring llb that are movable only in the axial direction, and a piston 711a of this hydraulic cylinder 11. A pin 12 that moves in the axial direction, and a cam hole 13 into which this pin 12 fits.
a hub 13 rotatably but immovably assembled in the axial direction to a housing 14 rotated by an engine (not shown); a gear 13b integrally formed at one end of the hub 13; A gear 15 is formed integrally with one end of a brevi 15 rotatably but immovably assembled in the axial direction to the gear 14 and meshes with the gear I3b.
a, etc., and the hydraulic oil applied to the hydraulic cylinder 11 from the hydraulic control circuit 2o causes the piston l to
When la moves to the right in the figure, the blade 1 rotates in the direction of the arrow in the figure, and the pitch (propeller pitch) of the blade 15 is changed to a high 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 keeps the hydraulic pressure discharged from the oil pump 21 constant, 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-port 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 boats 23a connected to the hydraulic cylinder 11, the boats 23b connected to the oil pump 21, and the boats connected to the oil sump 25 are controllable, and are held at the neutral position shown when each solenoid a, b is not energized. When solenoid a is energized, the solenoid valve moves upwards to connect boats 23a and 23b, and when solenoid b is energized, the solenoid valve moves downwards and connects boats 23a and 23b.
3a and the boat 23c are configured to communicate with each other. 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 m25, and the throttle 24 always releases a portion (a small amount) of the hydraulic oil supplied to the hydraulic cylinder 11 to the oil m25. When the solenoids a and b fail due to disconnection or disconnection, the hydraulic oil in the hydraulic cylinder 11 is released and the pitch of the blade 15 is set to a low pitch (fail-safe side in a commonly known single-engine airplane). The electronic control unit 30 includes a momentum sensor 31 that detects the airspeed (■) of the airplane, an atmospheric pressure sensor 32 that detects the atmospheric pressure P during operation, and an atmospheric temperature sensor 33 that detects the atmospheric temperature T during the operation. , an engine rotation speed sensor 34 that detects the rotation speed NE of the engine that drives the propeller of the airplane, and a throttle opening θth that determines the load of the engine.
It is composed of a throttle opening sensor 35 that detects the
1 to 35 are connected to a microcomputer 36, respectively. The microcomputer 36 has an interface for sending and receiving signals with each of the sensors 31 to 35, a CPU that performs arithmetic processing, and a program corresponding to the flowchart (see FIGS. 4 and 5) executed by the CPU. A ROM that stores the modules (see Figures 6 and 7) necessary for processing the program, and an RA that allows the CPU to temporarily store variables and the like when executing the program.
M, etc. are connected to a common bus. ROM
The map stored in the map stores engine output Ps (see Figure 6) corresponding to throttle opening θth and engine speed NH, and thrust coefficient Ct (see Figure 7) corresponding to power coefficient Cp and advancement rate J. There are two types of two-dimensional maps shown, and data that has been experimentally confirmed through theoretical consideration taking engine characteristics into account is stored for the engine output Ps corresponding to the throttle opening θth and the engine rotational speed NH. The airspeed sensor 31 essentially detects the aircraft speed, detects the momentum (2), and outputs a momentum signal representing the detected momentum VO. 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 pressure sensor 33 detects the atmospheric pressure IT 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 button yometer attached to the valve opening outputs an opening signal representing the detection interval θtho. Note that each of the sensors 31 to 35 outputs a detection signal of an analog value to the microcomputer 36, which converts it into a digital value at the interface of the microcomputer 36. The microcomputer 36 has each of these sensors 31
The signal line into which the detection signal outputted by ~35 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 6, the CPU starts executing the control program shown in FIG.
A series of steps 1200 is repeatedly executed. After the initial setting process is completed, the CPU reads each detection data from the detection signals from each sensor 31 to 35 in step 101O. That is, the airspeed ■0 detected by the momentum sensor 31, 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, and the throttle opening θt detected by the throttle opening sensor 35.
hO 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 0, and after reading the atmospheric pressure PO and atmospheric temperature TO, the CPU calculates the atmospheric density ρ0 in step 1020. In this embodiment, the elements necessary to obtain the maximum thrust at a certain throttle opening are the airspeed ■0, the atmospheric density ρ0, and the throttle opening θtho. After each element is obtained, steps 1030 to 1100 are performed. The engine rotation speed N BEST that can obtain the same maximum thrust is derived. First, in step 1030, the CPU selects the engine output knob (Ps(θth, NE) MA shown in FIG. 6 based on the detected current throttle opening θtho).
Ps-NE representing the relationship between the engine output and engine rotation speed at the throttle opening θtho with reference to P).
Calculate the line. Here, assuming that the number of revolutions of the propeller is NP and the diameter of the propeller is D, the engine output Ps is expressed by the following equation from the relationship with the power coefficient Cp. Ps=pO-Cp-NP-D (1) However, the propeller rotation speed NP is expressed by the engine rotation speed NE and a coefficient as follows: NP=-NE (2). Therefore, the power coefficient Cp is: Cp=fl(Ps, NE)...
(3) and calculated in step 1030 Ps-N
From the E line, the CPU calculates the CpNE line representing the relationship between the power coefficient and the engine rotation speed in step 1040. On the other hand, the advancement rate J is expressed as 1, -12L-81,D''-(4) from the momentum ■, the propeller rotation speed NP, and the propeller diameter, and is expressed by the engine rotation speed based on equation (2). Since the propeller rotation speed NP is derived from NE, the CPU calculates the relationship between the advancement rate J and the engine rotation speed NE using the following formula using the steering knob 1050. J=f3(NE)
... (5) By substituting the Cp-NE line calculated in step 1040 into the relationship between the progress rate J and the engine speed NE expressed by equation (5), the CPU calculates the following in step 106o. , a Cp-J line representing the relationship between the power coefficient and the progression rate can be calculated. When the relationship between the power coefficient Cp and the progress rate J is calculated, C
In step 1070, the PU refers to the thrust coefficient map (CT (Cp, J) MAP) shown in FIG. 7 and calculates the CT-J line representing the relationship between the thrust coefficient and the rate of progress. Regarding the progress rate J, from equations (4) and (5), the current momentum ■0
In step 1080, the CPU substitutes the CT-J line calculated in step 1070 above into equation (5) to calculate the relationship between the thrust coefficient and engine speed NE. CT − representing the relationship
Calculate the NE line. The thrust T is calculated from the thrust coefficient CT, propeller rotation speed NP, etc., as follows: T = ρ 0 ・CT-NP-D
... Since it is calculated in (6), the CPU substitutes equation (2) into equation (6) and the above CT-NE line in step 109o to calculate the relationship between thrust and engine speed. Calculate the represented T-NE line. At this point, it becomes possible to calculate the thrust that is output when the engine speed is changed under the current operational situation, and the CPU determines the engine speed (referred to as maximum thrust speed) NBEST at step 1100 at which the same thrust becomes the maximum. seek. Once this maximum thrust rotation speed N BEST is determined, CP
In step 1200, U executes a pitch control routine for the variable pitch propeller, and in the pitch control routine, the engine rotation speed NE is set to the maximum thrust rotation speed N BEST.
Control the pitch so that Specifically, the CPU reads the engine rotation speed NEO detected by the engine rotation speed sensor 34 in step 2000, and calculates the read engine rotation speed NEO and the current engine rotation speed NEO as described above in step 2010. Compare with the maximum thrust rotation speed N BEST. Now, the current engine speed NEO is the maximum thrust speed N
Suppose that it is smaller than BEST. 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 boat 2
3a to the boat 23C, which communicates with the oil sump 25. When the hydraulic cylinder 1] communicates with the oil reservoir 25, the hydraulic oil in the cylinder 11 is discharged, and the return spring ll
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. While the engine rotation speed NEO is smaller than the maximum thrust rotation speed N BEST, this step is 2000, 2010°2θ2.
0 routine is repeated, and the engine speed NEO gradually approaches the maximum thrust speed N BEST. By repeating this routine several times, the engine rotational speed NEO approaches the maximum thrust rotational speed N BEST, and finally the two coincide. Then, step 201
In the comparison at 0, it is determined that the engine rotation speed NEO and the maximum thrust rotation speed N BEST are equal, and step 203
0 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 flow control valve 23 is not displaced at all, and the electromagnetic valve stops at the neutral position. When the solenoid valve is in the neutral position, the hydraulic oil discharged from the oil pump 21 is transferred to the boat 23b of the solenoid flow control valve 23.
At the same time, the hydraulic cylinder 11 in the variable pitch propeller IO is also shut off at the boat 23a. Therefore, no more hydraulic oil is discharged 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, a small amount of hydraulic oil flows out from the throttle 24 due to the fail-safe function, 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 this is the maximum thrust rotation speed N BEST,
The pitch control routine ends and the process returns to step 1200, which is the main routine. When step 1200 is completed, the process proceeds to step 1200.
10, and the sensor 31 detects the flight status which changes from time to time.
to 35, and the above-described process is repeatedly executed. In the above explanation, the engine rotation speed NEO is smaller than the maximum thrust rotation speed N BEST calculated in steps 1010 to 1100, but the engine rotation speed NEO is smaller than the maximum thrust rotation speed N BEST. If it is large, it will look like this: Maximum thrust rotation speed N B in steps 1010 to 1100
After calculating the EST, a pitch control routine is executed in step 1200, and step 2 in the pitch control routine is executed.
Engine rotation speed NEO and maximum thrust rotation speed N at 010
When compared with BEST, it is determined that the engine rotational speed NEO is greater than the maximum thrust rotational speed N BEST, and step 2040 is executed. 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 blades 15 rotate in the direction of the same arrow, the pitch becomes higher pitch, so the horsepower absorbed by the blades 15 increases and the engine speed decreases. By repeating this routine several times, the engine rotational speed NEO approaches the maximum thrust rotational speed N BEST, and eventually the two coincide. Then, Step 201
In the comparison at 0, it is determined that the engine rotation speed NEO and the maximum thrust rotation speed N BEST are equal, and step 203
0 is executed, the pitch control routine ends, and the process returns to the main routine. In this way, if the calculated maximum thrust rotation speed N BEST is different from the current engine rotation speed NEO, the excitation currents of the solenoids a and b in the electromagnetic flow control valve 23 are controlled in the pitch control routine, and hydraulic control is performed. As a result of changing the pitch of the blades 15 in the variable pitch propeller 10, the engine rotation speed approaches the calculated maximum thrust rotation speed, and the maximum thrust can be generated in the operating state. With this configuration, maximum thrust can be obtained without separate engine throttle and torque opening control, simplifying the control system, and directly connecting the throttle lever and throttle valve operated by the pilot mechanically. 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 can be calculated by other means. It may also be configured to detect the density.Also, in the above embodiment, the maximum thrust rotation speed N BEST is calculated through a more complicated calculation process than the various control elements, but the three input control elements vOρ0.θtho
It is also possible to omit the above calculation process by creating a three-dimensional map based on the above. For example, the RO provided in the microcomputer 36
In M, a program corresponding to the flowchart shown in Fig. 8 is stored, and as shown in Fig. 9, the maximum thrust rotation speed N BEST corresponding to each combination of momentum ■, atmospheric density ρ, and throttle valve degree θth is calculated. Three-dimensional map N BEST (V, ρ, θth) MAP is memorized. These three-dimensional machines store the maximum thrust rotational speed N BEST that has been calculated in advance through the above calculation process assuming the changing conditions of momentum V, atmospheric density ρ, and throttle opening θth that may actually occur. It is something to do. When the engine is started, the CPU in the microcomputer 36 starts executing the control program shown in FIG. At step 1020, each detection data is read from the detection signal from each sensor 31 to 35, and further, at step 1020, the atmospheric density ρO
Calculate. In the next step 1110, the CPU uses the detected airspeed vO, the throttle opening θtho, and the calculated atmospheric density ρO as arguments to create a three-dimensional map N BEST (V, ρ) stored in the ROM. θth) Referring to the MAP, read out the maximum thrust rotation speed N BEST of the engine that can obtain the maximum thrust. Once this maximum thrust rotation speed N BEST is read out, the pitch control routine 1200 is executed in the same manner as in the above embodiment, and as a result, the engine rotation speed is made to match the maximum thrust rotation speed. With this configuration, the maximum thrust rotational speed is calculated without going through the above-described complicated calculation process, which reduces the calculation processing time and prevents the accumulation of errors in the calculation process. Furthermore, the three-dimensional map described above can also be composed of two two-dimensional maps. For example, the RO provided in the microcomputer 36
A program corresponding to the flowchart shown in FIG. 10 is stored in M, and a program corresponding to the flow chart shown in FIG.
and the atmospheric density ρ to read out a predetermined argument K.
The maximum thrust rotational speed N B is determined by the two-dimensional map K(V, ρ) MAP, the argument read in the first map as shown in FIG. 12, and the throttle opening 6th.
Second two-dimensional map N BEST (
K, θth) MAP are stored. In the above example, after the initial setting process in step 1000 when starting the engine, the three control elements 0. After obtaining ρO4θtho, the three-dimensional map is read out. However, in this embodiment, after executing step 1020,
First, in step 1120, the argument KO is read from the momentum 0 and the atmospheric density ρ0 by referring to the first two-dimensional map K(V, ρ) MAP, and in the subsequent step 1130, the argument KO is read out. KO and throttle opening θtho
Tokara 2nd 2D Ma Nobu N BEST (K,
θth) Maximum thrust rotation speed N BES with reference to the MAP
Read T. Once the maximum thrust rotational speed N BEST is read out, the pitch control routine described above is executed in step 1200. By preparing two two-dimensional maps in this manner, the storage capacity of the ROM can be reduced compared to the case where three-dimensional maps are prepared.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a claim correspondence diagram corresponding to the configuration 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 pitch variation in a variable pitch propeller. 4 is a flowchart corresponding to the main routine of the control program; FIG. 5 is a flowchart corresponding to the pitch control routine of the control program; FIG.
Figure 7 shows a map of engine output corresponding to throttle opening and engine speed, Figure 7 shows a map of thrust coefficient corresponding to power coefficient and advancement rate, and Figure 8 shows other control programs. Fig. 9 is a diagram showing a three-dimensional map of the maximum thrust rotation speed corresponding to momentum, atmospheric density, and throttle opening, Fig. 10 is a flowchart corresponding to other control programs, Fig. 11 12 is a diagram showing a map of the argument corresponding to momentum and atmospheric density, and FIG. 12 is a diagram showing a map of the maximum thrust rotation speed corresponding to the argument and throttle opening. Explanation of symbols 10/...Variable pitch mechanism, 20...Hydraulic control circuit, 30...Electronic control device, 31-35...Sensor,
36...Microcomputer, VO...Airspeed,
ρ0...Air density L θtho...Throttle opening i
, NEO...Engine speed, N BEST...Maximum thrust speed. Applicant Toyota Motor Corporation Representative Patent Attorney Teru Hase (1 other person) Figure 3 1O...Variable pitch mechanism 20...Hydraulic pressure? l, 11 control circuit 30-・Electronic control device 31 to 35 ・・Sen No. 36...Microcomputer Figure 10 Figure 11 Figure 12

Claims (1)

[Claims] A pitch control device for a variable pitch propeller that controls the pitch of a variable pitch propeller rotated by an engine, comprising: aircraft speed detection means for detecting aircraft speed; air density detection means for detecting air density; , a throttle opening detection means for detecting the opening of the throttle, and inputting the detected aircraft speed, the detected air density, and the detected throttle opening, and based on the characteristics of the engine and the characteristics of the variable pitch propeller. maximum thrust rotation speed detection means for detecting the maximum thrust rotation speed of the engine that produces the maximum thrust at the throttle opening; rotation speed detection means for detecting the rotation speed of the engine; and the detected rotation speed is the maximum thrust rotation speed. 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 pitch of the variable pitch propeller is as follows.