DK161629C - naval propulsion - Google Patents

Description

in

DK 161629 C

The invention relates to a ship propulsion system, in particular to a passenger ship, in which propulsion system is provided with a drive shaft provided with an adjustable screw, which is directly coupled to a slow-moving two-stroke diesel engine as a drive, whereby there are at least two auxiliary diesel engines each driven a generator.

For passenger ships, especially cruise ships, the required top speed is significantly above the maximum required speed of travel. This top speed is only used in exceptional cases, however, the propulsion systems must be designed for top speed, which has an oversize and consequently a poor utilization of the installed engine power.

On the other hand, for safety reasons, significantly more engine power is provided to generate the required electrical energy than necessary, thereby providing the required engine power solely by intermediate or fast-moving auxiliary motors. The installed surplus can therefore amount to e.g. 30-40%.

The object of the invention is to improve the utilization of the overall power installed on the ship in the form of diesel engines. This problem is solved by the present invention in that between the electric grid on board and each propulsion diesel engine there is an electric motor / generator which absorbs power from the grid on board and passes through the crankshaft of the propulsion diesel engine to the drive shaft or emits the excess propulsion power. to the web on board.

the engines In this way, the propulsion engine or 2

DK 161629 C

is designed so that, taking into account a safety margin, 90% of its maximum power produces the power needed at the most used travel speed, ie a basic load for the propulsion power, while higher ship speeds or propulsion effects are taken from the preferably in series with the drive shaft and the propulsion motor from the excess power reserve in the power reserve. electrical grids on board.

Thus, with the direct coupled two-stroke diesel engine, a propulsion system is available which is characterized by low fuel consumption, lower maintenance costs and loss of transmission losses.

When using a synchronous machine as motor / generator, it is expedient, after the synchronous speed has been reached, to effect only power increases to the propulsion power by changing the pitch of the adjustable screw blades.

It may be expedient for a certain power surplus due to low ship speed to increase the rpm to synchronous rpm of the engine / generator without increasing the power available for propulsion by increasing the blade of the adjustable screw. changes. The power surplus produced at the synchronous speed is then converted by the motor / generator into electrical energy and made available to the grid on board. The power of the generator / diesel engines can then be reduced. This allows electric energy to be generated with the economical two-stroke diesel engine.

For this purpose it is possible to connect a slow-moving 3

DK 161629 C

motor / generator directly on the crankshaft of the propulsion motor. If the dimensions of the necessary electrical machines become too bulky, then an interchange gear between the propulsion motor and the motor / generator may instead be built in. Then there must be an elastic shift between gears and propulsion engines.

In the following, the invention is explained in more detail by way of an embodiment.

FIG. 1 is a schematic representation of the new propulsion system; FIG. 2 is a sectional view of a variant of FIG. 1, and FIG. 3 is a diagram-like representation in which the required propulsion power is listed as ordinate and ship speed Vg as abscissa on the left and the crankshaft of the propulsion motor as abscissa on the right.

The FIG. 1, the propulsion system 1 shown has two drive shafts 1, at each end of which an adjustable screw 2 is mounted. The drive shafts 1 are connected directly to each a propulsion diesel engine 3 of the slow-moving two-stroke engine type. Of course, instead of two drive shafts 1, one or more.

For supplying the electrical grid on board, symbolically shown by a busbar 4, there are four or more generators 5. Each of these generators 5 is powered by its own auxiliary motor 6, which is a medium-speed or fast-moving four-stroke motor. The power installed with these motors is so great that the need for electrical energy can be met several times, e.g. 1.25-1.5 times.

4

DK 161629 C

According to the invention there are connected to the grid 4 on board two motor / generators 7, as in fig. 1 is connected through an exchange gear 8 - and in FIG. 2 directly - to the crankshaft 9 of the propulsion diesel engine 3, whereby an elastic shift clutch 10 in FIG. 1 allows mechanical separation of the motor / generators 7 from the crankshaft. As already described, the propulsion engines 3 are dimensioned such that with 90% of their maximum power they ensure compliance with the maximum required travel speed.

This effect corresponds to point 11 in the left diagram of FIG. 3. Thus, area A is covered by ship speeds only by the propulsion engines, whereby e.g. power adjustments are advantageously obtained by rpm changes.

The power requirement between points 11 and 12 in the left part of FIG. 3 to the speed range B can no longer be covered by the propulsion engines alone. According to the invention, in this area additional motors / generators 7 are connected as motors on the crankshaft 9.

As can be seen from the right part of FIG. 3, the propulsion power in point 11 is tied to a rpm on the crankshaft (point 13) which corresponds to the synchronous speed ns of the motor / generator 7 (fig. 2) and corresponds to this one (fig. 1).

The inherently conventional speed control for the propulsion engines is now designed so that this synchronous speed is also kept constant with further power increase, and further power increase is taken into account by changing the pitch of the adjustable screw blade. In this way, in point 14, the power required for the maximum ship speed 12 is reached, whereby

DK 161629 C

the power demand C is generated by the electric motor / generators 7 and by the grid on board respectively.

As already mentioned, significant differences in efficiency of 5 can be used between the two-stroke and four-stroke engines 3 and 6, respectively, at low ship speeds, e.g. in points 15 and 16 respectively of the diagrams in fig. 3, switch from the speed dependent power control to the screw blade control and at the same time increase the speed 10 from the value nx to the value n3. The power reserve of the propulsion motors 3 thus in hand in the area D is then fed by the motor / generators 7 as electrical energy in the grid 4 on board.

Claims (5)

6 DK 161629 C A ship propulsion system, in particular for a passenger ship, in which propulsion system is provided with at least one drive shaft (1) provided with an adjustable screw (2) and which is directly coupled to a slow-moving two-stroke diesel engine (3) as a propulsion engine, generating the electrical energy there are at least two auxiliary diesel engines (6), each driving a generator (5), characterized in that an electric motor / generator (7) exists between the electric grid (4) on board and each propulsion diesel engine (3) ) which takes power from the grid (4) on board and passes through the crankshaft (9) of the propulsion diesel engine (3) to the drive shaft (1), or delivers the excess propulsion power to the grid (4) on board. Propulsion system according to claim 1, characterized in that there exists an interchange gear (8) between the propulsion diesel engine (3) and the engine / generator (7). Propulsion system according to claim 2, characterized in that a shift clutch (10) exists between the propulsion diesel engine (3) and the engine / generator (7). Propulsion system according to any one of claims 1-3, characterized in that the motor / generator (7) is a synchronous machine. Propulsion system according to one of claims 1-5, characterized in that after obtaining the synchronous rpm (ns) of the motor / generator (7) power change takes place by means of an adjustment of the blades of the adjustable screw (2).