EP3864648B1

EP3864648B1 - A generator set

Info

Publication number: EP3864648B1
Application number: EP18789024.9A
Authority: EP
Inventors: Francesco Degano; Carlo PESTELLI; Virpi HANKANIEMI; Zengxin GAO; Moreno ALMERIGOGNA
Original assignee: Wartsila Finland Oy
Current assignee: Wartsila Finland Oy
Priority date: 2018-10-10
Filing date: 2018-10-10
Publication date: 2022-11-30
Anticipated expiration: 2038-10-10
Also published as: WO2020074074A1; EP3864648A1

Description

Technical field

The present invention relates to a generator set comprising an internal combustion piston engine, an electric generator mechanically coupled with the internal combustion piston engine so as to receive power to rotate the electric generator and a common base frame which the internal combustion piston engine and the electric generator are supported on and attached to according to the preamble of claim 1.

Background art

There is a general aim in installations of internal combustion engines that the transfer of engine vibrations and/or noise to the surrounding structures is kept as small as easily possible. Normally the engine is mounted on a particular solid base frame, which in turn is supported to a floor of a power plant, be it a stationary assembly, or to a land vehicle or a marine vessel. When it comes to engines exploited for production of electric power, and heat, if so desired, it is customary to install at least an engine and an electric generator on a common base frame, the unit being called as a generator set, which may also be referred to as a gen-set. The electric generator is mechanically coupled with the engine so that the engine provides power to the electric generator which in turn generates electric power to a grid to which it is connected.
Large internal combustion engines generate typically low frequency noise according to its firing frequency. Even though such generator sets are enclosed by noise attenuating enclosure, which in land based power plant is the plant building itself, there is a need of still improving the attenuation of noise generated by such a generator set, or a single engine.
RU2014123906A discloses soundproofing covering of a room by a soundproofing front flat-sheet and/or soundproofing non-flat formed panel, spaced mounted with reference to an oppositely located ceiling of the room, with the formation of respective closed air cavities.
KR20040003825A discloses an intake noise reducing apparatus which comprises a resonator communicated to an intake duct, an oil tank filled with an oil, a communicating pipe which allows for flow of oil between the resonator and the oil tank, the first sliding member which moves in a vertical direction in accordance with the height of the level of the oil in the resonator so as to change the volume of the resonator, the second sliding member which moves in a vertical direction in accordance with the height of the level of the oil in the oil tank, a potentiometer for detecting the height of the level of the oil in the oil tank, an actuator for moving the second sliding member in a vertical direction so as to adjust the height of the level of the oil in the oil tank; and an electronic control unit for determining the reference height on the basis of the engine RPM, and driving the actuator in such a manner that the level of the oil detected by the potentiometer reaches the reference height.
JPH10266870A discloses an active noise control system for generator set comprising a reference microphone and an anti-noise speaker in connection with an exhaust duct of an engine, the anti-noise speaker being arranged for generating a cancelling sound for cancelling the noise in the duct outlet on the basis of a reference signal and an error signal is controlled by the active noise control means.
JP2003108148A discloses an enclosure for a generator set comprises resonator chambers arranged to corners of the enclosure for attenuating noise generated by the generator set. Even if the solution may be advantageous as such, the resonator chambers inevitably consumes extra space which will be experienced either by limited inner space of the enclosure or by volume occupied by the enclosure.
US 4 733 750 A and DE 20 2017 101269 U1 disclose an enclosure for an engine or a generator set with a sound absorbing material at the base.
An object of the invention is to provide a generator set in which attenuation of noise to the surrounding air is considerably improved compared to the prior art solutions while the space consumption is minimized.

Disclosure of the Invention

Objects of the invention can be met substantially as is disclosed in the independent claim and in the other claims describing more details of different embodiments of the invention.
According to an embodiment of the invention a generator set comprising an internal combustion piston engine, an electric generator mechanically coupled with the internal combustion piston engine, is provided with a common base frame, which is provided with plurality of resonator units comprising a bordered resonator space, which resonator space is provided with at least one communication port so as to allow communication between the resonator space and its surroundings.
This way the noise generated is attenuated in close proximity to the source of the noise. According to the invention the resonator units are integrated or attached to the source of noise. Even the large generator set is in a building the walls of which may attenuate the noise to some extent, by means of the present invention it is possible to decrease the noise level already in the building. Also, this way the resonator units effect to the direct noise wave from the source and not so much to noise reflected from the walls of the building.
According to an embodiment of the invention the resonator unit is a Helmholtz resonator in which the resonator space is arranged in communication with the surroundings via at least one neck as a communication port.
According to an embodiment of the invention the resonator space comprises an air filled resonator space.
According to an embodiment of the invention the resonator space is at least partially formed by the structure of the base frame. This provides a further effect of inter alia material savings and results in a compact structure.
According to an embodiment of the invention the resonator unit is prefabricated resonator unit, separate to, and removably attached to the base frame. This provides a further effect of making it possible to assemble the resonator units into existing generator sets.
According to an embodiment of the invention the resonator unit is a perforated wall noise absorber in which the resonator space is arranged in communication with the surroundings via a perforation in at least one wall of the resonator unit.
According to an embodiment of the invention the generator set comprises more than two resonator units, each tuned to attenuate a same frequency.
According to an embodiment of the invention the generator set comprises a first set of resonator units tuned to attenuate a first frequency, and a second set of resonator units tuned to attenuate a second frequency.
According to an embodiment of the invention the resonator unit advantageously is tuned to attenuate a frequency corresponding to the firing frequency of the internal combustion piston engine.
According to an embodiment of the invention the generator set comprises a computer controller unit configured to run the engine at constant speed (RPM), and internal combustion piston engine is a four-stroke engine and the resonator unit is tuned to attenuate a first frequency $F 1 [Hz] = RPM / (60 \times 2) \times C,$
where

F1 is the first frequency,
RPM is the constant speed in revolutions per minute,
C is the number of cylinders.

According to another embodiment of the invention the generator set comprises a computer controller unit configured to run the engine at constant speed (RPM), and that internal combustion piston engine is a four-stroke engine and the resonator unit is tuned to attenuate

a first frequency $F 1 [Hz] = RPM / (60 \times 2) \times C,$
and a second frequency $F 2 [Hz] = RPM / (60 \times 2) \times C \times 2,$
where
F1 is the first frequency, F2 is the second frequency, RPM is the constant speed in revolutions per minute, C is the number of cylinders.

In other words the resonator unit is tuned to attenuate a base firing frequency of the engine and the first order harmonics of the firing frequency of the engine.
The exemplary embodiments of the invention presented in this patent application are not to be interpreted to pose limitations to the applicability of the appended claims. The verb "to comprise" is used in this patent application as an open limitation that does not exclude the existence of also unrecited features. The features recited in depending claims and in the figures are mutually freely combinable unless otherwise explicitly stated.

Brief Description of Drawings

In the following, the invention will be described with reference to the accompanying exemplary, schematic drawings, in which

Figure 1 illustrates a side view of a generator set provided with a base frame according to an embodiment of the invention,
Figure 2 illustrates a front view of a generator set provided with a base frame according to an embodiment of the invention,
Figure 3 illustrates a detail of a base frame according to an embodiment of the invention,
Figure 4 illustrates a detail of a base frame according to another embodiment of the invention, and
Figure 5 illustrates a front view of a generator set provided with a base frame according to another embodiment of the invention.

Detailed Description of Drawings

Figures 1 and 2 depict schematically an internal combustion piston engine 10 which is coupled with an electric generator 12 together forming a generator set 14. Figure 1 shows a side view of the generator set 14 and an end view II of the generator set in the direction of the arrow in the left margin of the Figure 1 is shown in the Figure 2. The internal combustion piston engine 10 and the electric generator 12 of the generator set 14 are mechanically coupled with each other via drive shafts using a suitable coupling so as to transmit power from the engine to rotate the electric generator 12. The generator set has a common base frame 16 on which the internal combustion piston engine 10 and the electric generator 12 are supported, and also releasably attached to the base frame 16. In the Figure 3 there is shown a detail view of the base frame 16 according to an embodiment of the invention.
The base frame 16 is constructed of suitable steel such that it comprises at least two parallel longitudinal beams 18.1, 18.2 substantially parallel with the longitudinal direction of the engine 10. The longitudinal beams 18.1 and 18.2 are coupled with each other e.g. by means of cross-beams 18.3 at least at the ends of the longitudinal beams 18.1, 18.2 of suitable length providing suitable distance between the longitudinal beams for rigidly supporting the engine 10 and the generator 12 as desired.
The base frame 16 of the generator set 14 is provided with plurality of resonator units 20 configured to attenuate noise generated by the generator set when in use. Particularly the resonator unit are tuned to attenuate low frequency noise having frequency below 200 Hz. Typically the engine is configured to run at constant speed when in use, and therefore the noise emitted from the generator set 14 a substantially constant frequency spectrum. Thus, the resonator units are configured, or tuned, to attenuate noise at certain frequency, which effectively attenuates the noise right where it is generated, that is in close proximity to the engine 10 of the generator set 14. The resonator unit 20 comprises a bordered resonator space 22, which may be referred to as a resonator cavity as well, which is filled only with the air, thus being a reactive noise absorber. Each resonator space is provided with at least one communication port 24 so as to allow communication between the resonator space and its surrounding air.
The longitudinal beams 18.1, 18.2 form a vertical wall of the base frame at its sides, and is therefore called as a side wall. The side wall is otherwise solid, except that there is the at least one communication port 24 arranged to the wall. The resonator space 22 is inside the longitudinal beam 18.1, 18.2, 18.3, under the engine 10 and the electric generator 12. In the embodiments of the Figures 1 to 3 the resonator space 22 is at least partially formed and bordered by the structure of the base frame 16. The base frame 16 is provided with intermediate walls 26 and an end wall 28 which border the number of resonator cavities 22 in the base frame 16. The intermediate walls 26 are substantially perpendicular to the vertical side wall of the longitudinal beams 18.1, 18.2 and the end wall 28 is parallel to the vertical side wall of the longitudinal beams 18.1, 18.2. Advantageously the number of separate resonator units 20 in the base frame 16 is at least twenty units 20. This way an effective combined attenuation effect of the noise can be obtained practically without consuming extra space for the purpose.
As it becomes clear also from the embodiment shown in the Figure 1 and 2, the base frame 16 is provided with a plurality of separate resonator units 20. There are at least two horizontal rows 30 of resonator units 20 in the base frame 16 according to the embodiment of Figure 1. The resonator unit 20 shown in the Figures 1 to 3 is a Helmholtz resonator in which the resonator space 22 is arranged in communication with the surrounding air via at least one neck 32 as a communication port 24. The neck 32 may be a tube or a channel of other suitable cross sectional area, such a square or quadrangle, or alike. The dimensioning of a Helmholtz resonator to attenuate a selected frequency is known as such for a skilled person in the art.
According to an embodiment of the invention all the resonator units are tuned to attenuate noise at a same frequency. Advantageously, in this case the resonator units are tuned to attenuate a firing frequency of the internal combustion piston engine.
Since the number of resonator units 20 in the base frame 16 is substantially large, according to another embodiment of the invention the generator set 14 comprises a first set of resonator units 20.1 tuned to attenuate a first frequency, and a second set of resonator units 20.2 tuned to attenuate a second frequency. The first and the second frequency are different frequencies. Advantageously, in this case the first frequency is a firing frequency of the internal combustion piston engine and the second frequency is a second order harmonics of the firing frequency.
Advantageously the generator set comprises a computer controller unit which is configured to run the engine at constant speed (RPM), and the internal combustion piston engine is a four-stroke engine and the resonator unit is tuned to attenuate a first frequency $F 1 [Hz] = RPM / (60 \times 2) \times C,$
where F1 is the first frequency, RPM is the constant speed in revolutions per minute, C is the number of cylinders.
According to an embodiment of the invention the computer controller unit configured to run the engine at constant speed (RPM), and the internal combustion piston engine is a four-stroke engine and the resonator unit is tuned to attenuate a first frequency $F 1 [Hz] = RPM / (60 \times 2) \times C,$
and a second frequency $F 2 [Hz] = RPM / (60 \times 2) \times C \times 2,$
where F1 is the first frequency, F2 is the second frequency, RPM is the constant speed in revolutions per minute, C is the number of cylinders.
For example, when a four stroke engine having 18 cylinders runs at 750 RPM, its combustion rate per cylinder, combustions per min = 375 c/min (every other revolution of the engine), and combustions per s = 6.25 c/s and thus combustion frequency is 112,5 Hz.
In the figure 4 there is shown an embodiment of the invention according to which the resonator unit is a perforated wall noise absorber in which the resonator space is arranged in communication with the surroundings via a perforation in at least one wall of the resonator unit 20.
According to embodiment of the invention the resonator unit is a separate prefabricated resonator unit 20'. This embodiment is disclosed in the Figure 5. The prefabricated resonator unit 20' is an individual entity which has a body with the resonator space and one or more a communication ports 24. Such a prefabricated resonator unit 20' is removably attached to the base frame 16. As can be seen from the Figure 4 when using prefabricated resonator unit 20' the communication port may open into a space under the engine 10 and the electric generator 12. Figure 4 also illustrates the aspect of the invention according to which the generator set 14 comprises a first set of resonator units 20.1' tuned to attenuate a first frequency, and a second set of resonator units 20.2' tuned to attenuate a second frequency. The first and the second frequency are different frequencies. Even if not shown, also in this embodiment the base frame may be provided with openings through which the communication ports 24 are in connection with the surrounding air.
While the invention has been described herein by way of examples in connection with what are, at present, considered to be the most preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various combinations or modifications of its features, and several other applications included within the scope of the invention, as defined in the appended claims. The details mentioned in connection with any embodiment above may be used in connection with another embodiment when such combination is technically feasible.

Claims

A generator set (14) comprising an internal combustion piston engine (10), an electric generator (12) mechanically coupled with the internal combustion piston engine (10) so as to receive power to rotate the electric generator (12) and a common base frame (16) is constructed of suitable steel such that it comprises at least two parallel longitudinal beams (18.1, 18.2) substantially parallel with the longitudinal direction of the engine (10), and the at least two parallel longitudinal beams (18.1, 18.2) are coupled with each other at least at the ends of the longitudinal beams (18.1,18.2) by means of cross beams (18.3) of suitable length providing suitable distance between the longitudinal beams (18.1, 18.2), which common base frame (16) the internal combustion piston engine and the electric generator (12) are supported on and attached to, characterized in that the base frame (16) of the generator set (14) is provided with plurality of resonator units (20, 20') comprising a bordered resonator space (22), which resonator space (22) is provided with at least one communication port (24) so as to allow communication between the resonator space (22) and its surroundings, and wherein the resonator space (22) is inside the longitudinal beam (18.1, 18.2, 18.3) under the engine (10) and the electric generator (12).
A generator set (14) according to claim 1, characterized in that the base frame (16) is provided with intermediate walls (26) and an end wall (28) which border the number of resonator cavities (22) in the base frame (16).
A generator set (14) according to claim 1, characterized in that the number of separate resonator units (20) in the base frame (16) is at least twenty units (20).
A generator set (14) according to claim 1, characterized in that the resonator unit (20') is a separate prefabricated resonator unit.
A generator set (14) according to claim 1, characterized in that the resonator unit (20, 20') is a Helmholtz resonator in which the resonator space (22) is arranged in communication with the surroundings via at least one neck (32) as a communication port (24).
A generator set (14) according to claim 1, characterized in that the resonator space (22) comprises an air filled resonator space (22).
A generator set (14) according to claim 1, characterized in that the resonator space (22) is at least partially formed by the structure of the base frame (16).
A generator set (14) according to claim 1, characterized in that the resonator unit is prefabricated resonator unit (20'), separate to, and removably attached to the base frame (16).
A generator set (14) according to claim 1, characterized in that the resonator unit (20, 20') is a perforated wall noise absorber in which the resonator space (22) is arranged in communication with the surroundings via a perforation in at least one wall of the resonator unit (20, 20').
A generator set (14) according to claim 1 or 5, characterized in that the generator set (14) comprises more than two resonator units (20, 20'), each tuned to attenuate a same frequency.
A generator set (14) according to claim 1 or 5, characterized in that the generator set (14) comprises a first set of resonator units (20.1, 20.1') tuned to attenuate a first frequency, and a second set of resonator units (20.2, 20.2') tuned to attenuate a second frequency.
A generator set (14) according to claim 10 or 11, characterized in that the resonator unit (20, 20') is tuned to attenuate a firing frequency of the internal combustion piston engine.
A generator set (14) according to claim 10, characterized in that the generator set (14) comprises a computer controller unit configured to run the engine at constant speed (RPM), and that internal combustion piston engine is a four-stroke engine and the resonator unit (20, 20') is tuned to attenuate a first frequency $F 1 [Hz] = RPM / (60 \times 2) \times C,$
where
F1 is the first frequency,

RPM is the constant speed in revolutions per minute,

C is the number of cylinders.
A generator set (14) according to claim 11, characterized in that the generator set (14) comprises a computer controller unit configured to run the engine at constant speed (RPM), and that internal combustion piston engine is a four-stroke engine and the resonator unit (20, 20') is tuned to attenuate a first frequency F1 [Hz] = RPM / (60 x 2) x C,
and a second frequency F2 [Hz] = RPM / (60 x 2) x C x 2, where F1 is the first frequency, F2 is the second frequency, RPM is the constant speed in revolutions per minute, C is the number of cylinders.