ES2704097T3 - Optimization of a propulsion system with a variable pitch propeller in a water vehicle during a stop maneuver - Google Patents

Abstract

Method for operating a propulsion system of a water vehicle during a stopping maneuver, in which the propulsion system has at least one rotating variable pitch propeller (1) having respectively blade propellers with a blade angle (12). ) adjustable and driven by means of a motor (3), the motor (3) being able to exert a motor torque (15) on the variable pitch propeller (1), a speed (13) of the watercraft and propeller speed number (11) of the at least one variable pitch propeller (1), characterized in that previously a characteristic line for the watercraft is determined, which links different initial speeds (17) of the watercraft at the beginning of the stopping maneuver with at least one time course of the blade angle (12) and with a time course of the number of revolutions of the propeller (11), in such a way that the propulsion system lasts When the stopping maneuver is operated according to the characteristic line, it results in a shortest travel path possible as short as possible of the water vehicle and the number of propeller revolutions (11) exceeds a predefinable critical number of revolutions, the propulsion system during the stop maneuver according to the characteristic line previously determined.

Description

DESCRIPTION

Optimization of a propulsion system with a variable pitch propeller in a water vehicle during a stop maneuver.

The invention relates to a method for operating a propulsion system of an aquatic vehicle during a stopping maneuver, in which the propulsion system has at least one rotating variable pitch propeller having respectively propeller blades with an angle of blade adjustable and driven by means of a motor, the motor being able to exert a torque on the variable pitch propeller, it being possible to determine a speed of the water vehicle and a number of revolutions of the propeller of the at least one variable pitch propeller. Furthermore, the invention relates to a control, to a water vehicle, to a computer program and to a computer program product for carrying out the process.

Such a method and a propulsion system of this type are used, for example, in water vehicles in which good maneuverability or very variable permanent speeds are required, for example ferries, passenger ships, feeders.

Unlike the conventional propeller with a fixed pitch, in the "controllable pitch propeller" or the variable pitch propeller, the propeller blades are fixed in a rotatable way to the hub. In this way, the pitch can be continuously adjusted from zero to maximum thrust in the forward or rearward direction, the step angle or the pitch ratio being also known as the blade angle.

To accelerate the water vehicle from the stop, the machine starts with zero thrust and accelerates, for example, to the speed of running speed. During the start it is not requested by a pair of propulsion. Therefore, the vehicle does not start immediately when the machine is started. The runaway of the propeller shaft and the motor connected to it by the current (for example, produced by ships passing in the port) is prevented by the propeller that is in zero thrust.

The water vehicles with variable pitch propeller usually do not have any inversion gear, at most, a reduction gear in the case of fast-spinning motors. Therefore, an essential weak point in the propulsion system is eliminated in comparison with conventional propulsion systems. With different speeds, the efficiency is more favorable than in the case of a fixed propeller.

When the engine is running, the propulsion can be switched from "forward" to "backward", which entails a considerable saving of time, since the machine no longer has to stop or slow down at the minimum number of revolutions. In this way, essentially improves maneuverability.

However, especially in this type of electric propulsion of boats with variable pitch propeller, during the emergency stop there is a reflow of power from the propeller, through the electric motor, since the propeller works as turbine and the electric motor works as generator. This effect in which, contrary to the normal propulsion regime, a negative pair acts on the propeller, is also known as the "pinwheel" effect. The power with which the propeller is driven, either, must be fed back to the on-board network with corresponding current converters, or it must be consumed through so-called braking resistors. In order to guarantee the stability of the on-board network and not to bring the diesel generators to the power return interval, there is therefore a high constructive and logistical expense. In addition, converters suitable for feedback are much more expensive than the variant that can be made only by motor.

A method and a control system for a variable pitch propeller of a watercraft are known from WO2005 / 044659A1, several operating modes being provided, for example, a maneuvering mode, a driving mode and a test mode . In addition, a transition sub-mode is provided for a smooth transition between the driving mode and the maneuvering mode and vice versa.

The object of the invention is to provide a method of the type mentioned at the beginning, which allows the rapid braking of the water vehicle in a simple manner.

This objective is achieved in a procedure of the type mentioned at the beginning with the following procedure steps, such that a characteristic line for the water vehicle is previously determined, which links different initial velocities of the water vehicle at the beginning of the stopping maneuver with at least one time course of the blade angle and with a time course of the number of revolutions of the propeller, such that the propulsion system which during the stopping maneuver is operated according to the characteristic line results in a path of stop as short as possible of the water vehicle and the number of propeller revolutions exceeds a critical number of revolutions, predefinable, the propulsion system being operated during the stopping maneuver according to the previously determined characteristic line.

This object is also achieved by means of a control comprising means for carrying out the method according to the invention, the means comprising a computer program according to claim 5 for execution in the control, the means comprising at least one computer unit and one unit. memory in which the characteristic line previously determined for the water vehicle is stored. In addition, this object is achieved by means of a water vehicle with at least one propulsion system and with the aforementioned control, the propulsion system having at least one rotating variable pitch propeller having respectively propeller blades with an adjustable blade angle and which can be actuated by means of a motor, it being possible for a motor torque to be exerted on the variable pitch propeller (1) by means of the motor, it being possible to determine by means of a sensor corresponding to at least one speed of the watercraft and a number of revolutions of propeller of the at least one variable pitch helix. Finally, the objective is also achieved by a computer program according to claim 5 and a computer program product according to claim 6.

According to the invention, the speed of the ship is determined, and the speed of water circulation with respect to the ship or the propeller can also be taken into consideration. For this, for example, sensors can be used. The number of propeller revolutions is also determined, for example, by means of additional sensors, especially in the form of a transmitter. In a converter-driven propulsion system with an electric drive motor, the number of helix revolutions can be determined, for example, by electrical currents, with which the motor is loaded by the converter.

Additionally, the helical pair of the at least one variable pitch helix can also be determined. For this purpose it can be used that the time change of the number of propeller revolutions is proportional to the difference between the motor torque and the propeller torque, being able to determine the motor torque with the help of the current in a propulsion system fed by a converter. which forms the torque, supplied to the motor.

The method according to the invention is used in aquatic vehicles with adjustable pitch propeller blades as well as with a pitch regulator for adjusting the pitch of the propeller blades. In addition, a control can be provided which can process sensor data and transmit commands to the step controller, to the motor, to the converter and, as the case may be, to other ship components and parts of the ship propulsion system.

The characteristic line according to which the propulsion system is operated during a stopping maneuver can be determined, for example, by means of a calculation or a simulation that is carried out for a given water vehicle or for a specific type of watercraft. For the determination of the characteristic line it can be used that during a stop maneuver there are forces on the water vehicle, such as the resistance of the water vehicle's hull due to the forward movement, the resistance of the oar and the thrust of the propeller. The resistance of the watercraft and the resistance of the rotor can be described, for example, by experiments with models or semi-empirical functions. For an equation of movement with informative value as a basis for calculation or simulation, the mass inertia of the water vehicle that can be assumed as known can also be taken into consideration.

In the determination of the characteristic line, especially in diesel electric drives, it is possible to differentiate between two situations: if the variable pitch propeller attacks a positive torque, the number of revolutions of the propeller can be adjusted within the framework of the available engine power. . On the other hand, if a negative torque is attacked in the propeller, the "reel" effect occurs and the propeller is driven by water, which increases the number of revolutions of the propeller.

During normal operation of the ship, the ship propulsion system produces an advance and the at least one variable pitch propeller has a positive blade angle, so that a positive torque is applied to the variable pitch propeller. Is that the positive blade angles are understood as those shovel angles that in a given direction of rotation of the variable pitch propeller produce a forward movement of the ship. Consequently, the negative blade angles are understood as those blade angles that in the same direction of rotation given the variable pitch propeller cause a retraction of the ship.

Depending on the previously determined characteristic line, it can be provided, for example, that during a stopping maneuver, the blade angle is modified from a positive blade angle until that blade angle is achieved with which the variable pitch propeller already it does not produce any advance. Then, the blade angle can be further modified until a negative blade angle is finally reached and recoil occurs. Especially because of the friction of the water that passes in front of the ship's hull, during this process a slowdown of the ship can occur in total. At the same time, the number of revolutions of the variable pitch propeller can also be modified. This can be achieved by defining a theoretical number of revolutions in the motor or for example also in such a way that the propulsion motor is separated from its power supply. According to the invention, the stopping maneuver results in a stopping path that is as short as possible of the water vehicle, the predefined critical speed value not exceeding the number of propeller revolutions. The critical speed value can be chosen in particular from such so as to avoid serious damage to the ship's propulsion system.

Depending on the characteristics of the watercraft and the initial speed of the watercraft at the beginning of the stopping maneuver, it is also possible that the characteristic line initially preserves the blade angle, especially to avoid a "pinwheel" effect " For a stopping path that is as short as possible during the stopping maneuver, an advantageous characteristic line, especially in the case of lower initial velocities of the watercraft, can be expected to initially increase the number of propeller revolutions, but at most up to the number value of critical revolutions.

In an advantageous embodiment of the invention, a distance of the watercraft is determined with respect to a collision obstacle, the propulsion system additionally performing a diversion maneuver, if the stopping path traversed by the watercraft during the stopping maneuver of the water vehicle is greater than the distance of the watercraft from the collision obstacle.

The collision obstacle can be, for example, stationary obstacles, such as reefs, port facilities and the like, but also moving obstacles, such as, for example, other water vehicles. The determination of the distance of the watercraft from the collision obstacle can be carried out especially optically or with the aid of radar measurements. Likewise, position data of the obstacle can be supplied to the propulsion system to determine the distance.

If the collision obstacle is mobile and is moving, in determining the distance, an obstacle course traversed during the stopping maneuver by the collision obstacle can be taken into consideration in particular. Therefore, the obstacle course can increase or decrease the admissible stopping path of the water vehicle, according to the direction in which the collision obstacle is moving.

The deviation maneuver can be optimized for example in such a way that the propulsion system has access to current position data of the water vehicle. For example, with the help of maps that include navigation data deposited or the depth of water, in this way you can check the feasibility of possible diversion maneuvers and finally you can select a diversion maneuver that is viable and at the same time guarantee a safe distance from the possible collision obstacle.

In the following, the invention is described and explained in detail with the help of the embodiments shown in the figures. They show:

FIGURE 1 a schematic representation of an exemplary embodiment of a propulsion system according to the invention,

FIGURE 2 time courses of a blade angle according to an example of a characteristic line,

FIGURE 3 time courses of a number of propeller revolutions according to another example of a characteristic line, FIGURE 4 a first example of a time course of a propeller number according to the characteristic line and of a speed of a watercraft ,

FIGURE 5 a second example,

FIGURE 6 a third example, and

FIGURE 7 a fourth example.

Figure 1 shows a schematic representation of an embodiment of a propulsion system according to the invention. A variable pitch propeller 1 is driven through a reduction gear 4 by a motor 3. The variable pitch propeller 1 has propeller blades each having an adjustable blade angle 12 which can be modified by an adjustment unit 5. The motor 3 is powered by a converter 2, the converter 2 receiving from part of a control 6 theoretical values relative to the number of motor revolutions 10. Control 6 is supplied with the real number of revolutions 11, determined by a transmitter 7, and control 6 continues to issue to the adjustment unit 5 theoretical values relative to blade angle 12.

Figure 2 shows time courses of a blade angle 12 according to an example of a characteristic line. As for the following figures, the characteristic line was previously determined and guarantees that a propulsion system of a corresponding water vehicle, which during a stopping maneuver is operated according to the characteristic line, results in a stopping distance traveled as far as possible. short possible and that the number of revolutions of propeller 11 does not exceed a predefinable critical number of revolutions. For the calculation or simulation for the determination of the characteristic line can be taken into consideration forces acting on the watercraft, such as the resistance of the hull of the watercraft due to the forward movement, the resistance of the oar as well as the thrust of the propeller. In addition, the mass inertia of the water vehicle can be used for the determination of the characteristic line.

Different time courses of the blade angle 12 are shown, with the time, on the axis and blade angle 12, and the initial velocity 17, respectively, being indicated on arbitrary units in the x-axis. In the representation, it is assumed that before the start of the stopping maneuver, a determined positive blade angle 12 is always applied, for example the blade angle 12 which produces the maximum advance. At the time tS, the stopping maneuver is started for different initial speeds 17. As can be clearly seen, the time until the complete inversion of the blade angle 12 depends on the initial velocity 17: with lower initial speeds 17, the angle of blade 12 can be reversed very quickly, and with higher initial speeds 17, this exemplary feature line no longer provides time for the reversal of blade angle 12.

The determined characteristic line can also take into consideration that during the operation of the watercraft before the stopping maneuver, different blade angles 12 are present. For greater ease, a corresponding graphic representation is dispensed with.

Figure 3 shows time courses of a number of revolutions of propeller 11 according to another example of characteristic line. Different time courses of the number of revolutions of propeller 11 are shown, indicating on the x-axis the time, on the axis and the number of revolutions of helix 11 and on the z-axis the initial speed 17, respectively in arbitrary units. In turn, at the time tS, the stopping maneuver for different initial speeds 17 is started, at the beginning of the stopping maneuver different numbers of revolutions of propeller 11. With lower initial speeds 17 and, as in this example, also with lower propeller speeds 11, at the beginning of the stopping maneuver, the number of propeller revolutions 11 is increased rapidly and considerably. With an initial speed 17 high in comparison, the number of propeller revolutions 11 is maintained. according to the present characteristic line. With initial speeds 17 still higher, in the course of the stopping maneuver the number of revolutions of propeller 11 is reduced.

Figure 4 shows a first example of a time course of a number of revolutions of propeller 11 according to the characteristic line and of a speed 13 of a watercraft. In addition, examples of the time course of a blade angle 12 and a torque coefficient 14 are shown, with the respective absolute value of the mentioned measurement quantity indicated on the ordinate axis and the time, respectively, in arbitrary units on the abscissa. . A positive torque coefficient 14 means that a positive torque acts in total on the variable pitch helix 1. As in the following figures, the curves represented can be different especially to the curves represented by way of example in figures 2 and 3.

At the beginning, the determined speed 13 and the number of revolutions of helix 11 of the watercraft are constant and high in comparison. For this, a positive blade angle 12 is applied which results in a positive torque coefficient 14.

At the time tS, a stopping maneuver is initiated and the blade angle 12 is reduced and finally it becomes negative angles. During this, at the same time, the number of revolutions of propeller 11 is increased, in such a way that the number of engine revolutions 10 increases until a maximum number of revolutions is reached. The maximum number of revolutions can be chosen, for example, in such a way that the number of revolutions of the propeller 11 does not exceed a predefinable critical number of revolutions. These measures have as a consequence that the coefficient of torque 14 decreases abruptly, but remains positive. A coefficient of negative torque 14 would indicate that a negative torque acts on the variable pitch helix 1 and, therefore, a "windlass" effect occurs. Meanwhile, the determined speed of the water vehicle decreases rapidly in comparison and the torque coefficient 14 adopts higher values after a certain period of time than at the beginning of the stopping maneuver, in which the sense of spin of the propeller. With a number of revolutions of propeller 11 being increased and a negative blade angle 12 applied, the determined speed 13 is constantly reduced until finally it adopts the value zero and the watercraft stops. For reference signs not shown or indicated here, see additional figures.

Figure 5 shows a second example of a time course of a number of revolutions of propeller 11 according to the characteristic line and of a speed 13 of a watercraft. In comparison with FIG. 4, the speed 13 and the number of revolutions of the propeller 11 are smaller before the beginning of the stopping maneuver. During the stopping maneuver the number of helix revolutions 11 is increased massively, only the blade angle 12 is gradually reversed. This results in a determined speed 13, increased at the beginning of the stopping maneuver, which is then reduced to zero. During the complete stop maneuver, the coefficient of torque 14 remains always positive, so that no "reel" effect is produced.

Figure 6 shows a third example of a time course of a propeller number 11 according to the characteristic line and a speed 13 of a watercraft. During the stopping maneuver, the number of revolutions of helix 11 remains unchanged and the angle of blade 12 is gradually reversed. The torque coefficient 14 remains positive during the full stop maneuver and the determined speed 13 decreases continuously until the water vehicle stops.

Figure 7 shows a fourth example of a time course of a number of revolutions of propeller 11 according to the characteristic line and of a speed 13 of a watercraft. The determined speed 13 and the number of helix revolutions 11 before the beginning of the stopping maneuver are high in comparison. At the beginning of the stopping maneuver, blade angle 12 reverses rapidly in comparison, the motor 3 separating from converter 2, so that the number of revolutions of propeller 11 initially decreases rapidly. Since, at the beginning of the stopping maneuver, the torque coefficient 14 becomes negative for a certain period of time, the "reel" effect occurs, so that the number of revolutions of the propeller 11 increases again. the lapse of time during which the "pinwheel" effect occurs, the torque coefficient 14 returns to positive values. During the complete stop maneuver, the determined speed 13 is continuously reduced, while the number of propeller revolutions 11 is maintained during the complete stop maneuver below the predefinable critical speed.

In summary, the invention relates to a method for operating a propulsion system of an aquatic vehicle during a stopping maneuver, in which the propulsion system has at least one rotating variable pitch propeller having respectively propeller blades with an adjustable blade angle and which is actuated by means of a motor, the motor being able to exert a torque on the variable pitch propeller, wherein a speed of the water vehicle and a number of revolutions of the propeller of the at least one propeller can be determined. variable step. Furthermore, the invention relates to a control, to a water vehicle, to a computer program and to a computer program product for carrying out the process. In order to make it possible to quickly braking the watercraft in a simple manner, it is proposed that previously a characteristic line for the watercraft be determined, which links different initial velocities of the watercraft at the beginning of the stopping maneuver with at least one time course respectively of the blade angle and with a time course of the number of revolutions of the propeller, in such a way that the propulsion system which, during the stopping maneuver, is operated according to the characteristic line results in a stopping distance traveled as short as possible. water vehicle and the number of revolutions of the propeller exceeds a critical number of revolutions, predefinable, the propulsion system being operated during the stopping maneuver according to the previously determined characteristic line.

Claims (6)

A method for operating a propulsion system of a watercraft during a stopping maneuver, in which the propulsion system has at least one rotating variable pitch propeller (1) having respectively propeller blades with a blade angle (12) adjustable and driven by means of a motor (3), the motor (3) being able to exert a torque (15) on the variable pitch propeller (1), and a speed (13) of the watercraft can be determined and a number of helix revolutions (11) of the at least one variable pitch propeller (1), characterized in that previously a characteristic line for the watercraft is determined, which links different initial speeds (17) of the watercraft to the beginning of the stopping maneuver with at least one time course of the blade angle (12) and with a time course of the number of revolutions of the propeller (11), in such a way that the propulsion system which uring the stopping maneuver it is operated according to the characteristic line, it results in a shortest travel path possible as short as possible of the water vehicle and the number of propeller revolutions (11) exceeds a predefinable critical number of revolutions. propulsion system during the stop maneuver according to the characteristic line previously determined. The method according to claim 1, wherein the distance of the watercraft is determined with respect to a collision obstacle, the propulsion system additionally performing a diversion maneuver, if the stopping path traveled by the watercraft during the maneuver The stopping position of the watercraft is greater than the distance of the watercraft from the collision obstacle. Control (6) for a water vehicle with at least one propulsion system, the control (6) having means for carrying out the method according to claim 1 or 2, wherein the means comprise a computer program for execution in the control (6), the means comprising at least one computer unit and a memory unit, in which the characteristic line previously determined for the watercraft is stored. 4. Water vehicle with - at least one propulsion system and - a control (6) made according to claim 3, the propulsion system having at least one rotary variable pitch propeller (1) having respectively propeller blades with an adjustable blade angle (12) and which can be driven by means of a motor (3), which can be exerted by means of the motor (3) a torque (15) on the variable pitch propeller (1), which can be determined by means of a sensor corresponding to at least one speed (13) of the watercraft and a number of revolutions of the propeller (11) of the at least one variable pitch helix (1). Computer program for carrying out a method according to one of the claims 1 to 2 running in a control (6) according to claim 3. 6. Computer-readable memory medium, in which a computer program according to claim 5 is stored.