FIELD OF THE DISCLOSURE

The present disclosure relates to multi-piston engines and, more particularly to the placement of auxiliary devices thereon. The present disclosure further concerns a method of attaching an auxiliary device to an engine block and a maintenance method of such a multi-piston engine. The present disclosure also concerns a marine vessel and a power plant having such a multi-piston engine

BACKGROUND OF THE DISCLOSURE

Conventionally large multi-piston engines, such as ones used in marine vessels, have been restricted with respect to their lateral dimensions by the width of the marine vessel, which in turn, dictate the width of the engine room.

Such premises have resulted in a long-standing practise of locating auxiliary devices, particularly ones associated to a fluid medium (e.g. oil pumps, water pumps, fuel pumps, compressed air -driven starter motors), at the longitudinal end of the engine.

While such arrangements have allowed maintaining conventional engines relatively narrow, access to the auxiliary devices may be restricted. Consequently, replacement or service of such auxiliary devices has often required removal of other components of the engine to obtain sufficient access.

BRIEF DESCRIPTION OF THE DISCLOSURE

An object of the present disclosure is to provide a multi-piston engine so as to alleviate the disadvantages mentioned above. A further object of the present disclosure is to provide a marine vessel, and a power plant having such a multi-piston engine. Yet a further object of the present disclosure is to provide a method for attaching an auxiliary device to an engine block and a method for maintenance of such an engine.

The object of the disclosure is achieved by the multi-piston engine, marine vessel, power plant and methods, which are characterized by what is stated in the independent claims. The preferred embodiments of the disclosure are disclosed in the dependent claims.

The disclosure is based on the idea of arranging an auxiliary device associated to a fluid medium on a lateral side of an engine block, at a longitudinal end thereof. This results in the auxiliary device being located at a less congested area of the engine, thereby improving access to the said auxiliary devices. According to a first aspect of the present disclosure, a multi-piston engine having a modular configuration corresponding to the number of pistons is provided. The engine comprises an engine block, which is suitably provided as a single monolithic structure, e.g., a cast piece. Advantageously, the multi-piston engine is a reciprocating internal combustion engine suitable for use in a marine vessel or a power plant. Typically, such engines have a nominal power output of 2 MW - 7 MW kW and a nominal operating speed of 250 - 1500 revolutions per minute. Naturally, such engines may be provided in an inline configuration or a V-configuration. Preferably, but not necessarily the engine comprises an electronic control system including, e.g., electronic fuel injection.

Moreover, the modular configuration of the engine is adapted to correspond to the number of pistons. That is, certain parts or components of the engine are provided at a number corresponding to the number of pistons, either directly or as a multiple thereof. Suitably, such modularly provided parts or components are identical with each other. Typically, such an engine with a modular architecture is configured by providing a number of power packs based on the requirements of the intended application. The number of power packs correspond to the number of cylinders and pistons, which dictates the shape and size engine block and the crank shaft. The power packs are then modularly equipped by providing a multiple of required components dedicated to each individual power pack. For example, a power pack could be provided as a cylinder specific group of components with which each cylinder is equipped. That is, such a power pack could include e.g., a cylinder head, a cylinder sleeve, a piston, a crank arm etc.

For example, the engine may be modularly configured by providing a number of individual cylinder heads corresponding directly to the number of pistons. That is, for each cylinder, an individual cylinder head is provided. Such cylinder heads would preferably be identical with respect to each other. Moreover, such cylinder heads are preferably individually removable from the engine block. Alternatively, or in addition, a cam shaft of the engine could be provided as a plurality of cam shaft sections longitudinally attached one after another, such that the cam shaft has a number of identical cam shaft sections corresponding to the number of pistons. For example, each such sections may comprise an intake cam, an exhaust cam and one or more bearing portions. It should be noted, that although such cam shaft sections of the cam shaft are identical, they may be attached to each other with an angular offset to achieve desired valve timing for each cylinder. Naturally, the cam shaft may additionally comprise additional, non-identical section such as end sections. Particularly, an auxiliary device associated to a fluid medium is arranged on a lateral side of the engine block, at a longitudinal end thereof. Such an auxiliary device is also provided in mechanical power transmission with the engine. For example, the auxiliary device could be gear or belt driven by the crank shaft, cam shaft or any intermediate shaft gear or pulley. In a similar manner, the auxiliary device could alternatively, or in addition, also drive a shaft of the engine.

Multiple benefits follow from such an arrangement. Particularly, placement of the auxiliary devices on the lateral side of the engine block allows modifications and/or adaptations of the auxiliary devices in response to the modular variation of the engine. That is, placement on the lateral side of the engine block enables the size, type or quantity of auxiliary devices to be changed depending on what variant of the modular structure is being equipped. For example, larger engines with a greater number of cylinder could auxiliary devices with a larger capacity or a greater number of auxiliary devices, whereas a relatively smaller engine with a fewer number of cylinder could be equipped with auxiliary devices with a smaller capacity of a fewer number thereof. As mentioned above, this improves access to said auxiliary device and facilitates servicing, maintenance or replacement thereof. That is, the auxiliary devices are no longer located at the longitudinal ends of the engine block where access is restricted due to congested space and/or safety precautions. Particularly, a turbocharger and/or a flywheel are commonly located at longitudinal ends of an engine and impede access thereat. Improved access to the auxiliary devices both facilitates servicing and replacement of the auxiliary devices, and allows maintenance operations such as visual inspection (e.g., to detect leakages), acoustic inspection, temperature measurements and sensor replacement, even during operation of the engine. Furthermore, such an arrangement contributes towards minimizing time spent by operating personnel in the vicinity of the engine, as more reliable sensor measurements enable a greater portion of monitoring to be conducted from a control room.

Reliability of sensors has become more important as the electrical control and automation of engine (e.g., electronically controlled fuel injection) has become more and more common, thereby requiring reliable information on the operating conditions of the engine.

Moreover, the provision of the auxiliary devices at the lateral side (as opposed to the longitudinal end), enables a greater offset of the auxiliary devices from the crankshaft, which in turn offers greater flexibility for adapting a suitable transmission ratio for the auxiliary device by allowing arrangement of required gearing, intermediate shafts and/ or intermediate gears between the auxiliary device and the crankshaft, flywheel of cam shaft. Unless explicitly otherwise stated, in the context of this disclosure the term longitudinal is used to describe a direction parallel with a crankshaft of the engine, whereas the term lateral is used to describe a horizontal direction transverse to the longitudinal. Respectively, the word vertical is used to describe a direction transverse to the horizontal. That is, the longitudinal ends of the engine block are the sides thereof corresponding to opposing axial ends of the crankshaft, and the lateral sides of the engine block extend between the longitudinal ends thereof.

Moreover, unless explicitly otherwise stated, in the context of this disclosure the term auxiliary device is used to refer to the device proper, that is not including e.g., possible piping associated to the device.

Moreover, unless otherwise stated, in the context of this disclosure the longitudinal end of the engine block is to be understood as a longitudinally extending region extending from an end surface at a longitudinal end of the engine block for a distance of 1/10 - 1/4 of the longitudinal dimension of the engine block.

Preferably, but not necessarily, the auxiliary device is one of a group of auxiliary devices each corresponding to a respective fluid medium. Said group of auxiliary devices comprises a starter motor driven by compressed air, an oil pump, a fuel pump and a water pump.

Such a starter motor driven by compressed air is suitably coupled for mechanical power transmission with the engine by geared engagement with the flywheel of the engine. Moreover, the type, size or even the number of the starter motor(s) driven by compressed air may be adapted based on the number of pistons so as to provide a sufficient torque required to reliably start the engine.

Such an oil pump, in turn, is suitably coupled for mechanical power transmission with the engine by geared engagement with the crankshaft. Such geared engagement may naturally comprise one or more intermediate gears and/or corresponding shafts. Moreover, the output flow of the oil pump is suitably adapted in accordance with the number of pistons in the engine so as to provide sufficient lubricant circulation. For example, this could be done by adapting internal components (such as internal gears) of the oil pump. This would allow interchangeability with other pumps having a similar or identical casing. Consequently, a single oil pump could be kept as an onboard back-up replacement for multiple.

Such a fuel pump is suitably coupled for mechanical power transmission with the engine by geared engagement with the crankshaft. Such geared engagement may naturally comprise one or more intermediate gears and/or corresponding shafts. Moreover, the output flow of the fuel pump is suitably adapted in accordance with the number of pistons in the engine so as to provide sufficient fuel flow. For example, this could be done by adapting internal components (such as internal gears) of the fuel pump, choosing a fuel pump with suitable flow capacity, or by providing a suitable number of fuel pumps to achieve a desired fuel flow. If multiple fuel pumps are used, the pumps are preferably identical with each other. For example, engines with 2-6 pistons could be provided with a single whereas engines with 7 or more pistons could be provided with two or more fuel pumps.

Such a water pump is also suitably coupled for mechanical power transmission with the engine by geared engagement with the crankshaft. Such geared engagement may naturally comprise one or more intermediate gears and/or corresponding shafts. Moreover, the output flow of the water pump is suitably adapted in accordance with the number of pistons in the engine so as to provide sufficient water flow. For example, this could be done by adapting internal components (such as internal gears) of the water pump, choosing a water pump with suitable flow capacity, or by providing a suitable number of water pumps to achieve a desired fuel flow. Moreover, multiple wate pumps could be provided so as to provide for separate water circulations.

Naturally, the engine may comprise two or more from the group of auxiliary devices. It should be noted that the engine may also comprise multiple auxiliary devices of each type, e.g., two or more water pumps, oil pumps, fuel pumps or air driven starter motors.

More preferably, but not necessarily, two or more from the group of auxiliary devices are arranged, with respect to each other, at different lateral sides, different longitudinal ends, or both.

For example, at least the starter motor driven by compressed air, the oil pump, the fuel pump, and the water pump may each be provided as auxiliary devices associated to a fluid medium and coupled in mechanical power transmission with the engine arranged on the lateral side of the engine block at a longitudinal end thereof.

Most suitably each of such auxiliary devices are positioned at a respective separate lateral side and a longitudinal end of the engine block. positioned at a respective separate lateral side and a longitudinal end of the engine block.

In an embodiment according to the first aspect of the present disclosure, two or more auxiliary devices corresponding to a same fluid medium may be positioned at the same lateral side and longitudinal end of the engine block. For example, the group of auxiliary devices may comprise a high temperature water pump and a low temperature water pump, such that the hight temperature water pump and the low temperature water pump are positioned on the same lateral side and longitudinal end of the engine block. In such a case, the high temperature water pump and the low temperature water pump are preferably driven by a common output shaft of the engine.

In an embodiment according to the first aspect of the present disclosure, at least one auxiliary device extends past the engine block in the longitudinal direction thereof.

In an embodiment according to the first aspect of the present disclosure, a space above at least one auxiliary device is unobstructed, thereby allowing removal of said auxiliary device by hoisting from above the engine.

It should be noted that the first aspect of the present disclosure encompasses the combination of any two embodiments, or variants thereof, as discusses above.

According to a second aspect of the present disclosure, a marine vessel is provided. Particularly, the marine vessel comprises the multi-piston engine discussed above in connection with the first aspect of the present disclosure.

The engine may be configured to power the propulsion system of the marine vessel at least in part. Alternatively, the engine may be configured to power other applications of the marine vessel.

According to a third aspect of the present disclosure, a power plant is provided. Particularly, the power plant comprises the multi-piston engine discussed above in connection with the first aspect of the present disclosure.

According to a fourth aspect of the present disclosure, a method of attaching an auxiliary device to an engine block is provided. The method comprises a step of providing an engine block, and subsequently a step of attaching an auxiliary device, associated to a fluid medium, to a lateral side of the engine block at a longitudinal end thereof, such that the auxiliary device is coupled in mechanical power transmission with the engine.

Naturally, the auxiliary device or its placement with respect to the engine block may suitably be as discussed in connection with the first aspect of the present disclosure.

According to a fifth aspect of the present disclosure, a method for maintenance of the engine according to an embodiment of the first aspect, where a space above at least one of auxiliary devices is unobstructed, thereby allowing removal of said auxiliary device by hoisting from above the engine. The method comprises a step of removing an auxiliary device, the space above which is suitably unobstructed, from the multi-piston engine by hoisting vertically. Naturally, said auxiliary device is one associated to a fluid medium and coupled in mechanical power transmission with the engine, as discussed in connection with the first aspect of the present disclosure.

The method further comprises a step of servicing the removed auxiliary device or providing a replacement auxiliary device, and subsequently, attaching the serviced auxiliary device or the replacement auxiliary device to the multi-piston engine by hoisting vertically.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the disclosure will be described in greater detail by means of preferred embodiments with reference to the accompanying drawings, in which

Fig. 1 is a schematical representation of a multi-piston engine according to an embodiment of the present disclosure, as seen as a plan view from above;

Fig. 2 and Fig. 3 are schematical representations of the engine of Fig. 1 , as seen as plan views from opposing lateral sides of the engine, respectively, and

Fig. 4 and Fig. 5 are schematical representations of the engine of Fig. 1 , as seen as plan views from opposing longitudinal ends of the engine, respectively.

DETAILED DESCRIPTION OF THE DISCLOSURE

Fig. 1 is a schematical representation of a multi-piston engine 1 according to an embodiment of the present disclosure, as seen as a plan view from above. Firstly, it should be noted that, for the purpose of clarity, the multi-piston engine 1 is shown in the appended drawings in a configuration where many components are not illustrated.

The multi-piston engine illustrated in Fig. 1 comprises an engine block 2. The engine block 2 extends longitudinally between opposing longitudinal ends 2c and 2d thereof transverse to the longitudinal. Moreover, the engine block 2 defines opposing lateral sides 2a and 2b parallel with the longitudinal.

In the embodiment of Fig. 1 the longitudinal direction of the engine is parallel with an axis of a crankshaft (not illustrated). That is, the longitudinal direction of the engine block 2 corresponds to a direction along which a plurality of cylinders is provided.

Moreover, Fig. 1 clearly depicts auxiliary devices 3, 4, 5 and 6 (hereafter commonly referred to as 3-6) arranged on the engine block at lateral sides 2a, 2b thereof. Moreover, the auxiliary devices 3-6 are arranged on the longitudinal ends 2c, 2d of their respective lateral side 2a, 1 b.

Particularly, the auxiliary devices 3-6 are ones associated to a fluid medium and coupled in mechanical power transmission with the engine 1. A starter motor 3 driven by compressed air is provided on the engine block 2, at the longitudinal end 2c of the lateral side 2b. An oil pump 4 is provided on the engine block 2, at the longitudinal end 2d of the lateral side 2b. A fuel pump 5, in turn, is provided at the longitudinal end 2d of the lateral side 2a, whereas a water pump 6 is provided at the longitudinal end 2c of the lateral side 2a.

In Fig. 1 , the auxiliary devices 3-6 are arranged, with respect to each other, at different lateral sides 2a, 2b and longitudinal ends 2c, 2d, although more than one auxiliary device associated to a fluid medium may arranged at a single lateral side and longitudinal ends

Fig. 2 schematically illustrates the multi-piston engine 1 of Fig. 1 as a side view seen from the lateral side 2b. Particularly, the starter motor 3 driven by compressed air and the oil pump 4 can be seen as arranged on the engine block 2 at opposing longitudinal ends 2c, 2d of the lateral side 2b.

Also Fig. 3 schematically illustrates the multi-piston engine 1 of Fig. 1 as a side view, although seen from the lateral side 2a. Particularly, the fuel pump 5 and the water pump 6 can be seen as arranged on the engine block 2 at opposing longitudinal ends 2d, 2c of the lateral side 2a. In addition, Fig. 3 clearly illustrates the water pump 6 comprising a high temperature water pump 6a and a low temperature water pump 6b. That is, two auxiliary devices corresponding to the same fluid medium, namely the high temperature water pump 6a and the low temperature water pump 6b, are arranged at the same lateral side 2a and longitudinal end 2c. In the particular embodiment of Fig. 3, the high temperature water pump 6a and the low temperature water pump 6b are driven by a common output shaft of the engine. That is, the two pumps 6a, 6b are arranged co-axially on the same output shaft of the multi-piston engine 1 .

Fig. 4 schematically illustrates the multi-piston engine 1 of Fig. 1 as an end view seen from the longitudinal end 2d. Fig. 4 clearly illustrates the oil pump 4 and the fuel pump 5 on arranged on opposing lateral sides 2b and 2a, respectively, at the longitudinal end 2d thereof.

As mentioned above in connection with the first aspect of the present disclosure, one or more of the auxiliary devices 3-6 may extend past the engine block 2 in the longitudinal direction thereof. Such a situation is depicted in e.g., Fig. 2, where starter motor 3 driven by compressed air amd the oil pump 4, extend longitudinally past the engine block, i.e. over the longitudinal end 2c and 2d, respectively. Moreover, Fig. 3 shows the water pump 6 extending longitudinally past the engine block 2, i.e. over the longitudinal end 2c.

Fig. 5, in turn, schematically illustrates the multi-piston engine 1 of Fig. 1 as an end view seen from the longitudinal end 2c. Fig. 5 clearly illustrates the water pump 6 and the starter motor 3 driven by compressed air arranged on opposing lateral sides 2a and 2b, respectively, at the respective longitudinal ends 2c thereof.

It should be noted that although the appended drawings illustrate an embodiment of the present disclosure in connection with a multi-piston engine having six cylinders in an inline -configuration, the present disclosure may readily be utilized with multi-piston engines having another number of cylinders and/or another cylinder configuration, such as a V- configuration.

LIST OF REFERENCE NUMERALS

1 multi-piston engine

2 engine block

2a, 2b lateral side of engine block

2c, 2d longitudinal end of engine block

3 starter motor driven by compressed air

4 oil pump,

5 fuel pump 5

6 a water pump

6a high temperature water pump

6b low temperature water pump