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EP-4735754-A1 - INJECTION APPARATUS

EP4735754A1EP 4735754 A1EP4735754 A1EP 4735754A1EP-4735754-A1

Abstract

An injection apparatus (500) comprises: - an inlet (IN1) to receive a liquid (LIQ1), - a nozzle (NOZ1) having one or more orifices (OR1) to form droplets (P1) from the liquid (LIQ1), - one or more flow channels (DUC1) to convey the liquid (LIQ1), - a coupling element (M1) to couple ultrasound (UW1) to the liquid (LIQ1), and - a transducer (SPK1) to vibrate the coupling element (M1), wherein the liquid (LIQ1) is conveyed from the inlet (IN1) to the one or more orifices (OR1) via the one or more flow channels (DUC1), wherein the injection apparatus (500) is arranged to guide the ultrasound (UW1) from the coupling element (M1) to the nozzle (NOZ1) via the liquid (LIQ1) contained in the one or more flow channels (DUC1).

Inventors

  • ÖSTERROOS, Mikael Andre
  • AXELSSON, Martin
  • VUOHIJOKI, Antti
  • NALLANNAN, BALASUBRAMANIAN

Assignees

  • Wärtsilä Finland Oy

Dates

Publication Date
20260506
Application Date
20230628

Claims (14)

  1. 1 . An injection apparatus (500), comprising: - an inlet ( I N 1 ) to receive a liquid (L IQ 1 ), - a nozzle (NOZ1 ) having one or more orifices (OR1 ) to form droplets (P1 ) from the liquid (LIQ1 ), - one or more flow channels (DLIC1 ) to convey the liquid (LIQ1 ), - a coupling element (M1 ) to couple ultrasound (UW1 ) to the liquid (LIQ1 ), and - a transducer (SPK1 ) to vibrate the coupling element (M1 ), wherein the liquid (LIQ1 ) is conveyed from the inlet (IN1 ) to the one or more orifices (OR1 ) via the one or more flow channels (DLIC1 ), wherein the injection apparatus (500) is arranged to guide the ultrasound (UW1 ) from the coupling element (M1 ) to the nozzle (NOZ1 ) via the liquid (LIQ1 ) contained in the one or more flow channels (DLIC1 ).
  2. 2. The injection apparatus (500) of claim 1 , wherein the one or more flow channels (DLIC1 ) and the liquid (LIQ1 ) contained in the flow channels (DLIC1 ) operate as a liquid waveguide (WG1 ) to guide the ultrasound (UW1 ) via the liquid (LIQ1 ) contained in the flow channels (DLIC1 ).
  3. 3. The injection apparatus (500) of claim 1 or 2, wherein the injection apparatus (500) comprises a first acoustic transmission line (APATH1 ) for transmitting ultrasound (UW1 ) from the coupling element (M1 ) to the one or more orifices (OR1 ) via the liquid (LIQ1 ), wherein the injection apparatus (500) comprises a second acoustic transmission line (APATH2) for transmitting ultrasound (LIW21 ,UW22) from the coupling element (M1 ) to the one or more orifices (OR1 ) entirely via solid materials (MAT1 , MAT2).
  4. 4. The apparatus (500) according to any of the claims 1 to 3, wherein the coupling element (M1 ) is a membrane, which is arranged to bear a pressure difference (PLIQI-PA) between the pressure (PLIQI) of the liquid (LIQ1 ) and an ambient pressure (PA), in a situation where the pressure difference (PLIQI-PA) is greater than 100 kPa.
  5. 5. The apparatus (500) according to any of the claims 1 to 4, wherein the distance (LAPATHI ) between the coupling element (M1 ) and the one or more orifices (OR1 ) is in the range of 50 mm to 500 mm.
  6. 6. The apparatus (500) according to any of the claims 1 to 5, wherein the injection apparatus (500) comprises a flow control valve (VAL1 ) for controlling the flow of the liquid (LIQ1 ), wherein the ultrasound (UW1 ) is guided from the coupling element (M1 ) to the one or more orifices (OR1 ) via the valve (VAL1 ), in a situation where the valve (VAL1 ) is open.
  7. 7. The apparatus (500) according to any of the claims 1 to 6, wherein the fuel injection apparatus (500) comprises a flow control valve (VAL1 ) for controlling the flow of the liquid (LIQ1 ), wherein the injection apparatus (500) comprises an actuator coil (COIL1 ) to open the valve (VAL1 ), and the distance (LAPATHI ) between the coupling element (M1 ) and the one or more orifices (OR1 ) is greater than the distance (Lei) between the actuator coil (COIL1 ) and the orifices (OR1 ).
  8. 8. The apparatus (500) according to any of the claims 1 to 7, wherein the transducer (SPK1 ) is arranged to vibrate at a vibration frequency (fi), which is in the range of 20 kHz to 3 MHz.
  9. 9. The apparatus (500) according to any of the claims 1 to 8, wherein at least one portion of the waveguide (WG1 ) is dimensioned to resonate at the vibration frequency (fi) of the transducer (SPK1 ).
  10. 10. The apparatus (500) according to any of the claims 1 to 9, wherein sound pressure level (puw2) in the liquid (LIQ1 ) at the one or more orifices (OR1 ) is greater than 10% of the sound pressure level (puwo) in the liquid (LIQ1 ) at the coupling element (M1 ).
  11. 11. A reciprocating internal combustion engine (ENG1 ), comprising the injection apparatus (500) according to any of the claims 1 to 10, wherein the injection apparatus (500) is arranged to inject the droplets (P1 ) to an intake duct (MAN1 ) of the engine (ENG1 ).
  12. 12. A reciprocating internal combustion engine (ENG1 ), comprising the injection apparatus (500) according to any of the claims 1 to 10, wherein the injection apparatus (500) is arranged to inject the droplets (P1 ) directly to a combustion space (COMBU1 ) of a cylinder (CYL1 ) of the engine (ENG1 ).
  13. 13. A method of operating the engine (ENG1 ) of claim 11 or 12, wherein the liquid (LIQ1 ) is methanol (CH3OH), ammonia (NH3), or water (H2O).
  14. 14. A method of operating the engine (ENG1 ) of claim 11 or 12, comprising replacing the transducer (SPK1 ) with a second transducer while the engine (ENG1 ) is running.

Description

INJECTION APPARATUS FIELD The present invention relates to injecting a liquid in a reciprocating internal combustion engine. BACKGROUND It is known that a fuel injector of an internal combustion engine may comprise an ultrasonic transducer on one end of an ultrasonic horn, such that the opposite end of the horn is immersed in the fuel close to the injector's exit orifices. SUMMARY An object is to provide an apparatus for injecting a liquid in an engine. An object is to provide a method for injecting a liquid in an engine. An object is to provide an engine, which comprises the injecting apparatus. An object is to provide a method for operating the engine. According to an aspect, there is provided an apparatus according to claim 1 . Further embodiments are defined in the other claims. The scope of protection sought for various embodiments of the invention is set out by the independent claims. The embodiments, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the invention. The apparatus may be used for injecting atomized liquid into the combustion space of a cylinder of a reciprocating internal combustion engine. The liquid may be injected either to an intake duct of the engine, or directly into the cylinder. The liquid may be e.g. a fuel or a liquid additive. The liquid may be e.g. diesel oil. The liquid may be e.g. methanol. The liquid may be e.g. liquified ammonia. The liquid additive may be e.g. water. The engine may be e.g. the main engine of a ship. The atomizing nozzle of the apparatus comprises one or more orifices for atomizing the liquid, i.e. for converting an amount of the liquid into small droplets. The diameter of the formed droplets may be e.g. in the range of 1 m to 20 pm. The apparatus may utilize the ultrasound to facilitate the atomization. The apparatus may sonicate the liquid, i.e. may agitate the liquid by applying ultrasound energy. The apparatus may energize the liquid with the ultrasound. The ultrasound may e.g. reduce the size of the atomized droplets and/or may provide more uniform droplet size distribution. Large droplets, if entrained into the cylinder, may cause incomplete combustion and/or may compromise lubrication. The ultrasound may reduce the risk of forming large droplets. The apparatus may comprise a flow control valve for starting and stopping a flow of the liquid. The apparatus may utilize the ultrasound to facilitate operation of the flow control valve. The ultrasound may e.g. allow more precise timing of the start of the liquid flow via the flow control valve. The precise start of the liquid flow may further reduce the risk of forming large droplets. The apparatus comprises an ultrasonic transducer for generating the ultrasound. The apparatus may transmit the ultrasound from the transducer to the atomizing nozzle via the liquid. Transmitting the ultrasound to the atomizing nozzle via the liquid may allow increased freedom for selecting the position of the atomizing nozzle and for selecting the position of the transducer with respect to the cylinder head. For example, the atomizing nozzle may be mounted to a first position, and the transducer may be mounted to a second different position. The first position may be selected e.g. to optimize trajectories of the atomized droplets. The second position may be selected e.g. to ensure efficient cooling of the transducer. The space around the cylinder head of the engine is typically limited. Transmitting the ultrasound via the liquid may allow increased freedom for selecting the positions of the various tubes, sensors, and cables which are connected to the cylinder head. The apparatus may use one or more flow channels for conveying the liquid to the atomizing nozzle, and the apparatus may use the liquid contained in said one or more flow channels for transmitting the ultrasound to the atomizing nozzle. In particular, the one or more flow channels and the liquid contained in them may be arranged to operate as a liquid waveguide, for guiding the ultrasound with relatively low losses. BRIEF DESCRIPTION OF THE DRAWINGS In the following examples, several variations will be described in more detail with reference to the appended drawings, in which Fig. 1a shows, by way of example, in a cross-sectional side view, an injection apparatus, in a situation where the flow control valve of the injection apparatus is closed, Fig. 1 b shows, by way of example, in a cross-sectional side view, the injection apparatus, in a situation where the flow control valve is open, Fig. 2 shows, by way of example, in a cross-sectional side view, an acoustic transmission line of the injection apparatus, Fig. 3 shows, by way of example, in a cross-sectional side view, injecting atomized liquid to the intake duct of an engine, Fig. 4a shows, by way of example, a control system of an engine, Fig. 4b shows, by way of example, a c