Patent Description:
Generally, a ship receives friction resistance of water during marine navigation on its submerged surface of the ship's bottom. Especially for large ships, e.g. cargo ships, a large portion of the ship's hull resistance of results from friction resistance generated by relative flow of outside water at the ship's bottom.

To reduce ship's hull friction resistance air lubrication can be used, particularly by discharging air into surroundings of the ship's hull. The reduction of friction resistance has a large fuel economy improving effect, and thus represent effective means to reduce the CO<NUM> emission of the ship.

In the state of the art, there are various systems and approaches for the production of air bubbles for the hull lubrication. For instance, for the generation of air bubbles for hull lubrication, the prior art teaches direct usage of exhaust gas of the driving engine or to use separate electrical compressors or blowers. However, the known systems for hull lubrication have some disadvantages, for example in terms of energy consumption and efficiency. Further air supply arrangements are also known from documents <CIT> or <CIT>.

Accordingly, in view of the above, there is a demand for improved air supply apparatuses for ships as wells as for improved methods of supplying air to an air lubrication device of ships which at least partially overcome the problems of the state of the art.

In light of the above, an air supply apparatus for a ship and a method of supplying air to an air lubrication device of a ship according to the independent claims are provided. Further aspects, advantages, and features are apparent from the dependent claims, the description, and the accompanying drawings.

According to an aspect of the present disclosure, an air supply apparatus for a ship is provided. The air supply apparatus includes a first turbocharger having a first compressor and a first turbine being drivable by exhaust gas provided from one or more engines. The first compressor is coupled to the first turbine via a transmission configured for changing a speed of the first compressor. Additionally, the air supply apparatus includes an air lubrication device for resistance reduction of the ship. The first compressor is connected with the air lubrication device for supplying air to the air lubrication device.

Accordingly, the air supply apparatus of the present disclosure is improved compared to conventional apparatuses used for air lubrication type ships. In particular, embodiments of the air supply apparatus as described herein are improved with respect to energy efficiency. More specifically, by providing an air supply apparatus with a first turbocharger having a transmission coupling the first turbine with the first compressor for supplying air to the air lubrication device, the amount of air supplied to the air lubrication device can be controlled by using the transmission. More specifically, the first turbocharger, particularly the first compressor, is employed to compress low pressure air which subsequently is fed to the air lubrication device for air bubble generation under the vessel's hull to reduce water-hull friction of a ship. Less friction for the vessel's hull results in an overall reduction of energy usage of the ship. Accordingly, for example by employing the transmission to increase the speed of the first compressor compared to the speed of the first turbine the amount of air supplied to the air lubrication device can be increased resulting in an increased bubble generation under the vessel's hull. Thus, compared to the state of the art, a higher reduction of water-hull friction of the ship can be achieved. As result thereof, the overall reduction of energy usage of the ship can be reduced such that savings of fuel can be achieved resulting in a reduction of the overall operation costs.

Thus, according to a further aspect of the present disclosure, a ship including an air supply apparatus according to any embodiments described herein is provided.

According to another aspect of the present disclosure, a method of supplying air to an air lubrication device of a ship is provided. The method includes driving a first turbocharger by using exhaust gas from one or more engines. Additionally, the method includes changing a speed of a first compressor of the first turbocharger by using a transmission coupled to a first turbine and to the first compressor of the first turbocharger. Further, the method includes supplying air from the first compressor of the first turbocharger to the air lubrication device.

Accordingly, it is to be understood that embodiments of the present disclosure provide for an air supply apparatus, a ship including the air supply apparatus, and a method of supplying air to an air lubrication device of the ship, which are improved with respect to energy efficiency such that operation costs can be reduced.

So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the disclosure and are described in the following:.

Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each figure. Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with any other embodiment to yield yet a further embodiment. It is intended that the present disclosure includes such modifications and variations.

Within the following description of the drawings, the same reference numbers refer to the same or to similar components. Generally, only the differences with respect to the individual embodiments are described. Unless specified otherwise, the description of a part or aspect in one embodiment can apply to a corresponding part or aspect in another embodiment as well.

With exemplary reference to <FIG>, an air supply apparatus <NUM> according to the present disclosure is described. According to embodiments, which can be combined with other embodiments described herein, the air supply apparatus <NUM> includes a first turbocharger <NUM> having a first compressor <NUM> and a first turbine <NUM>. The first turbine <NUM> is drivable by exhaust gas provided from one or more engines <NUM>. In this regard, it is to be noted, that "drivable by exhaust gas" can be understood in that exhaust gas is provided for driving. Accordingly, the first turbine <NUM> may be connected to the one or more engines <NUM>, e.g. by one or more pipes, such that the one or more engines <NUM> can supply exhaust gas to the first turbine <NUM>. The one or more engines <NUM> may be turbocharged. Accordingly, it is to be understood that the exhaust gas supplied from the one or more engines <NUM> to the first turbine <NUM> can already be expanded in one or more turbochargers of the one or more engines <NUM>. The first compressor <NUM> is coupled to the first turbine <NUM> via a transmission <NUM> configured for changing a speed of the first compressor <NUM>. In particular, the transmission <NUM> can be configured for varying a speed of the first compressor <NUM>. For example, the transmission <NUM> can be configured for increasing the speed of the first compressor <NUM> compared to the speed of the first turbine <NUM>. Additionally or alternatively, the transmission <NUM> can be configured for decreasing the speed of the first compressor <NUM> compared to the speed of the first turbine <NUM>. Further, as exemplarily shown in <FIG>, the air supply apparatus <NUM> includes an air lubrication device <NUM> for resistance reduction of the ship. The first compressor <NUM> is connected with the air lubrication device <NUM>, particularly via a second air supply pipe <NUM>, for supplying air to the air lubrication device <NUM>.

Accordingly, beneficially an air supply apparatus with improved efficiency is provided. In particular, by providing a first turbocharger with a transmission as described herein has the advantage that the speed of the first compressor used for supplying air to the air lubrication device can be varied, and thus the amount of air supplied to the air lubrication device can be adjusted. For example, by using the transmission to increase the speed of the first compressor, the amount of air supplied to the air lubrication device can be increased. Accordingly, by decreasing the speed of the first compressor by means of the transmission, the amount of air supplied to the air lubrication device can be decreased. Hence, the amount of air supplied to the air lubrication device can be controlled on demand.

For example, by increasing the speed of the first compressor compared to the first turbine by means of the transmission provided there between, the efficiency of the first compressor for supplying air to the air lubrication device can be increased. Consequently, the effectivity of the air lubrication device can be improved, resulting in an increased bubble generation under the vessel's hull and thus a higher reduction of water-hull friction of the ship. As result thereof, the overall reduction of energy usage of the ship can be reduced such that savings of fuel can be achieved resulting in a reduction of the overall operation costs.

According to embodiments, which can be combined with other embodiments described herein, the transmission <NUM> can be a mechanical transmission, an electrical transmission, a pneumatic transmission or a hydraulic transmission. According to an example, which can be combined with other embodiments described herein, the transmission <NUM> includes a generator and an electric motor.

It is to be understood, that a transmission as described herein, e.g. the first transmission <NUM> and/or the second transmission <NUM> described in the following, can be configured to be variable. In other words, the first transmission <NUM> and/or the second transmission <NUM> can have a variable transmission ratio. Accordingly, a transmission as described herein may be configured for providing a changeable transmission ratio. Thus, the speed of the first compressor <NUM> and/or the second compressor <NUM> can beneficially be adjusted and controlled during operation of the ship, i.e. during operation of the one or more engines <NUM>, particularly independently from the speed of the connected turbine, e.g. the first turbine <NUM> and/or the second turbine <NUM>, as described herein.

With exemplary reference to <FIG>, according to embodiments, which can be combined with other embodiments described herein, the air supply apparatus <NUM> further includes a second turbine <NUM> in parallel to the first turbine <NUM>. As exemplarily shown in <FIG>, the first turbine <NUM> and the second turbine <NUM> can be coupled to the first compressor <NUM> via the transmission <NUM>.

With exemplary reference to <FIG>, according to embodiments, which can be combined with other embodiments described herein, the air supply apparatus further includes a second turbocharger <NUM> having a second compressor <NUM> and a second turbine <NUM>. The second turbine <NUM> is drivable by exhaust gas provided from the one or more engines <NUM>. Accordingly, the second turbine <NUM> may be connected to the one or more engines <NUM>, e.g. by one or more pipes, such that the one or more engines <NUM> can supply exhaust gas to the second turbine <NUM>. Additionally or alternatively, the second turbine <NUM> can be drivable by exhaust gas provided from the first turbine <NUM>. Accordingly, the second turbine <NUM> may be connected to the first turbine <NUM>, e.g. by one or more pipes, such that the first turbine <NUM> can supply exhaust gas to the second turbine <NUM>. As exemplarily shown in <FIG>, the second compressor <NUM> is connected with the air lubrication device <NUM>, particularly via a third air supply pipe <NUM>, for supplying air to the air lubrication device <NUM>.

According to another optional implementation, which can be combined with other embodiments described herein, the second turbine <NUM> may be drivable by compressed air supplied from the first air supply pipe <NUM>, as exemplarily shown in <FIG>, to the second turbine <NUM>. Accordingly, it is to be understood that an air supply pipe (not explicitly shown in the figures) from the third compressor <NUM> to the second turbine <NUM> may be provided. Similarly, according to another example, which can be combined with other embodiments described herein, the first turbine <NUM> may be drivable by compressed air supplied from the first air supply pipe <NUM> (shown in <FIG>) to the first turbine <NUM> Accordingly, it is to be understood that an air supply pipe (not explicitly shown in the figures) from the third compressor <NUM> to the first turbine <NUM> may be provided.

As exemplarily shown in <FIG>, typically the second compressor <NUM> is coupled to the second turbine <NUM> via a further transmission <NUM>. The further transmission <NUM> is configured for changing a speed of the second compressor <NUM>.

In particular, the further transmission <NUM> can be configured for varying a speed of the second compressor <NUM>. For example, the further transmission <NUM> can be configured for increasing the speed of the second compressor <NUM> compared to the speed of the second turbine <NUM>. Additionally or alternatively, the further transmission <NUM> can be configured for decreasing the speed of the second compressor <NUM> compared to the speed of the second turbine <NUM>.

According to embodiments, which can be combined with other embodiments described herein, the further transmission <NUM> can be a mechanical transmission, an electrical transmission, a pneumatic transmission or a hydraulic transmission. According to an example, which can be combined with other embodiments described herein, the further transmission <NUM> includes a generator and an electric motor.

With exemplary reference to <FIG>, according to embodiments, which can be combined with other embodiments described herein, the air supply apparatus further includes a third turbocharger <NUM> having a third compressor <NUM> and a third turbine <NUM>. For example, the third turbocharger <NUM> can be a turbocharger or several turbochargers for charging the one or more engines <NUM>. In this regard, it is to be noted that the third turbocharger <NUM> shown in the figures may represent one or more turbochargers. Accordingly, it is to be understood that the one or more engines <NUM> may be charged or not (i.e. uncharged). As exemplarily shown in <FIG>, the third turbine <NUM> is connected with an exhaust gas receiver <NUM> of the one or more engines <NUM> via a first exhaust gas pipe <NUM>. Accordingly, it is to be understood, that typically the turbocharger of the air supply apparatus according to embodiments described herein, particularly the first turbocharger <NUM>, is a separate turbocharger not employed for charging the engine. In other words, the first turbocharger <NUM> is a secondary turbine-compressor pair provided in addition to a turbocharger for charging the engine. In particular, according to embodiments described herein which can be combined with other embodiments described herein, no mechanical force is taken from an engine's turbocharger main turbine (e.g. the third turbine <NUM>) to the air supply apparatus.

According to embodiments, which can be combined with other embodiments described herein, the first exhaust gas pipe <NUM> can be connected to a flow controller <NUM> for controlling an exhaust gas flow provided from the exhaust gas receiver <NUM> to the third turbine <NUM>, as exemplarily shown in <FIG>. In particular, the flow controller <NUM> may be provided in a first bypass piping <NUM> bypassing the third turbine <NUM>.

With exemplary reference to <FIG>, according to embodiments, which can be combined with other embodiments described herein, the first turbine <NUM> can be connected with the third turbine <NUM> via a second exhaust gas pipe <NUM>. The second exhaust gas pipe <NUM> can be connected to a bypass valve <NUM> for controlling an exhaust gas flow provided from the third turbine <NUM> to the first turbine <NUM>. In particular, the bypass valve <NUM> may be provided in a second bypass piping <NUM> bypassing the first turbine <NUM>.

As exemplary shown in <FIG>, according to embodiments, which can be combined with other embodiments described herein, the third compressor can be connected with an air receiver <NUM> of the one or more engines <NUM> via a first air supply pipe <NUM>. In particular, as exemplarily shown in <FIG>, the first air supply pipe <NUM> includes a charge air cooler <NUM>.

With exemplary reference to <FIG>, according to embodiments, which can be combined with other embodiments described herein, a further flow controller <NUM> may be provided downstream of the first turbine <NUM> of the first turbocharger. The piping in which the further flow controller <NUM> is provided can be connected via an exhaust gas connection <NUM> to the exhaust gas outlet piping <NUM>. The exhaust gas outlet piping <NUM> may be part of an exhaust system. The exhaust system can include an exhaust gas aftertreatment apparatus and/or a silencer before the exhaust gas is released to the environment. In this regard, it is to be noted that an exhaust gas aftertreatment apparatus and/or a silencer may also be provided in the other embodiments described herein.

Accordingly, from <FIG> it is to be understood, that according to another aspect of the present disclosure a ship <NUM> including an air supply apparatus according to any embodiments described herein is provided. Thus, a ship with a more energy efficient system for water-hull friction reduction can be provided, such that the overall operation costs can be reduced.

With exemplary reference to the flowchart shown in <FIG>, a method <NUM> of supplying air to an air lubrication device of a ship according to the present disclosure is described.

According to embodiments, which can be combined with other embodiments described herein, the method <NUM> includes driving (represented by block <NUM> in <FIG>) a first turbocharger <NUM> by using exhaust gas from one or more engines <NUM>. Additionally, the method includes changing (represented by block <NUM> in <FIG>) a speed of a first compressor <NUM> of the first turbocharger <NUM> by using a transmission <NUM> coupled to a first turbine <NUM> and to the first compressor <NUM> of the first turbocharger <NUM>. Further, the method includes supplying (represented by block <NUM> in <FIG>) air from the first compressor <NUM> of the first turbocharger <NUM> to the air lubrication device <NUM>.

In particular, changing (represented by block <NUM> in <FIG>) the speed of a first compressor <NUM> may include varying the speed of the first compressor <NUM>. For example, changing the speed of the first compressor <NUM> by using the transmission <NUM> can include increasing the speed of the first compressor <NUM> compared to the speed of the first turbine <NUM>. Additionally or alternatively, the changing the speed of the first compressor <NUM> by using the transmission <NUM> can include decreasing the speed of the first compressor <NUM> compared to the speed of the first turbine <NUM>.

With exemplary reference to <FIG>, according to embodiments, which can be combined with other embodiments described herein, changing (represented by block <NUM> in <FIG>) the speed of the first compressor <NUM> comprises using (represented by block <NUM> in <FIG>) a second turbine <NUM> in parallel to the first turbine <NUM>. The first turbine <NUM> and the second turbine <NUM> are coupled to the first compressor <NUM> via the transmission <NUM>.

According to embodiments, which can be combined with other embodiments described herein, the method <NUM> further includes controlling (represented by block <NUM> in <FIG>) an amount of air provided to the air lubrication device <NUM> by controlling a rotational speed of the first turbocharger <NUM>. The rotational speed of the first turbocharger <NUM> can be controlled by controlling an exhaust gas flow provided to a third turbine <NUM> of a third turbocharger <NUM> being connected with an exhaust gas receiver <NUM> of the one or more engines <NUM>. The exhaust gas flow provided to the third turbine <NUM> of the third turbocharger <NUM> can be controlled by using (represented by block <NUM> in <FIG>) a flow controller <NUM>, as exemplarily shown in <FIG> and <FIG>. In particular, the flow controller <NUM> can be provided in a first bypass piping <NUM> bypassing the third turbine <NUM>, as exemplarily shown in <FIG> and <FIG>. Additionally or alternatively, controlling (represented by block <NUM> in <FIG>) the amount of air provided to the air lubrication device <NUM> can include controlling a rotational speed of the first turbocharger <NUM> by controlling an exhaust gas flow provided to the first turbine <NUM> by using (represented by block <NUM> in <FIG>) a bypass valve <NUM>, as exemplarily shown in <FIG> and <FIG>. In particular, the bypass valve <NUM> can be provided in a second bypass piping <NUM> bypassing the first turbine <NUM>. Additionally or alternatively, controlling (represented by block <NUM> in <FIG>) an amount of air provided to the air lubrication device <NUM> can include controlling a rotational speed of the first turbocharger <NUM> by using (represented by block <NUM> in <FIG>) a further flow controller <NUM> provided downstream of the first turbine <NUM> of the first turbocharger, as exemplarily described with reference to <FIG>.

With exemplary reference to <FIG>, according to embodiments, which can be combined with other embodiments described herein, the method <NUM> further includes driving (represented by block <NUM> in <FIG>) a second turbocharger <NUM> by using exhaust gas from the one or more engines. Additionally or alternatively, driving (represented by block <NUM> in <FIG>) the second turbocharger <NUM> can be conducted by using exhaust from the first turbine <NUM>. The second turbocharger <NUM> has a second compressor <NUM> coupled to a second turbine <NUM> via a further transmission <NUM>. The further transmission <NUM> is configured for changing a speed of the second compressor <NUM>. Additionally, the method <NUM> as exemplarily illustrated in <FIG> includes changing (represented by block <NUM> in <FIG>) a speed of the second compressor <NUM> by using the further transmission <NUM>. Further, the method <NUM> includes supplying (represented by block <NUM> in <FIG>) air from the second compressor <NUM> of the second turbocharger <NUM> to the air lubrication device <NUM>.

Accordingly, in view of the above, it is to be understood that embodiments described herein beneficially provide for an improved air lubrication device for which the amount of air supplied to the air lubrication device can be controlled and adjusted. In particular, as described herein, compared to the state of the art, the effectivity of the air lubrication device can be improved by employing a transmission for increasing the speed of a compressor used for supplying air to the air lubrication device. Accordingly, an increased bubble generation under the vessel's hull and thus a higher reduction of water-hull friction of the ship can be achieved, resulting in a reduction of the overall operation costs. Further, compared to the state of the art, embodiments as described herein have the advantage that residual energy of the turbine of the engine's turbocharger can be employed for operating the air supply apparatus. As consequence thereof, compared to the state of the art, embodiments as described herein provide for an improved energy efficiency. Moreover, embodiments as described herein beneficially provide for the possibility to compensate the so-called mismatching between compressor and turbine, by utilizing a separate turbocharger with a transmission coupling the turbine with the compressor used for bubble generation for hull lubrication.

Claim 1:
An air supply apparatus (<NUM>) for a ship (<NUM>), comprising:
- a first turbocharger (<NUM>) having a first compressor (<NUM>) and a first turbine (<NUM>) being drivable by exhaust gas provided from one or more engines (<NUM>), the first compressor (<NUM>) being coupled to the first turbine (<NUM>) via a transmission (<NUM>) configured for changing a speed of the first compressor (<NUM>) with respect to the first turbine (<NUM>), the first turbocharger (<NUM>) being a secondary turbine-compressor pair provided in addition to a turbocharger for charging the one or more engines (<NUM>); and
- an air lubrication device (<NUM>) for resistance reduction of the ship, wherein the first compressor (<NUM>) is connected with the air lubrication device (<NUM>) for supplying air to the air lubrication device (<NUM>).