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CN-122029348-A - Fuel injection device, piston engine, acoustic resonator and method for operating a piston engine

CN122029348ACN 122029348 ACN122029348 ACN 122029348ACN-122029348-A

Abstract

A fuel injection device for a piston engine comprises a fuel injector (1) configured to inject liquid fuel into an inlet passage (5) of the engine, and a component (2) for generating a sound field and applying the sound field to the fuel injected into the inlet passage (5) to atomize the injected fuel outside the fuel injector (1).

Inventors

  • B. Naranan
  • T. Hakara
  • A. Voyozi

Assignees

  • 瓦锡兰芬兰有限公司

Dates

Publication Date
20260512
Application Date
20231018

Claims (20)

  1. 1. A fuel injection device for a piston engine, the fuel injection device comprising a fuel injector (1) configured to inject liquid fuel into an inlet channel (5) of the engine, and a component (2) for generating a sound field and applying the sound field to the fuel injected into the inlet channel (5) to atomize the injected fuel outside the fuel injector (1).
  2. 2. The fuel injection device according to claim 1, wherein the means for generating a sound field comprises at least one acoustic resonator (2) arranged at least partially in the inlet channel (5).
  3. 3. The fuel injection device according to claim 2, wherein the acoustic resonator (2) is configured to operate by introducing a pressurized gas into the acoustic resonator (2).
  4. 4. A fuel injection device according to claim 3, wherein the fuel injection device is configured to introduce exhaust gas into the acoustic resonator (2) to operate the acoustic resonator (2).
  5. 5. A fuel injection device according to claim 3 or 4, wherein the acoustic resonator (2) is provided with an opening (3C) for discharging at least a part of the pressurized gas introduced into the acoustic resonator (2) such that the discharged pressurized gas can influence the flow direction of the fuel jet injected by the fuel injector (1).
  6. 6. The fuel injection device according to claim 5, wherein the acoustic resonator (2) is configured such that the pressurized gas discharged from the acoustic resonator (2) counteracts the effect of the air flow within the inlet channel (5) in a direction that deflects the fuel jet away from the longitudinal axis of the fuel injector (1).
  7. 7. The fuel injection device according to any one of claims 2 to 6, wherein the acoustic resonator (2) comprises a cavity (3) having a closed end (3A) and an open end (3B) and means (4) for introducing pressurized gas into the cavity (3) via the open end (3B) of the cavity (3).
  8. 8. The fuel injection device according to claim 7, wherein the length of the cavity (3) is adjustable to allow adjustment of the fundamental frequency of the acoustic resonator (2).
  9. 9. The fuel injection device of claim 7 or 8, wherein the cavity has a length of 10mm-30mm.
  10. 10. The fuel injection device according to any one of claims 7 to 9, wherein an angle between the fuel injection direction and a longitudinal direction of the cavity (3) is 0-45 degrees.
  11. 11. The fuel injection device according to any one of claims 7 to 10, wherein the open end (3B) of the cavity (3) is provided with an opening (3C) at one side of the cavity (3), the opening (3C) facing the fuel injected by the fuel injector (1).
  12. 12. The fuel injection device according to claim 11, wherein the fuel injector (1) and the acoustic resonator (2) are configured such that at least a portion of the fuel is injected towards the opening (3C) of the cavity (3).
  13. 13. The fuel injection device according to any one of claims 7 to 12, wherein the acoustic resonator (2) is arranged to protrude into the inlet channel (5) through a wall of the inlet channel (5) such that the open end (3B) of the cavity (3) is closer to the wall than the closed end (3A) of the cavity (3).
  14. 14. The fuel injection device according to any one of claims 7 to 13, wherein the fuel injection device comprises a valve for controlling the timing of supplying pressurized gas into the cavity (3) of the acoustic resonator (2).
  15. 15. The fuel injection device according to any one of claims 7 to 14, wherein the fuel injection device comprises a pressure regulating member for controlling the pressure of the pressurized gas introduced into the cavity (3) of the acoustic resonator (2).
  16. 16. The fuel injection device according to any one of claims 2 to 15, wherein the acoustic resonator (2) is annularly arranged around the fuel injector (1).
  17. 17. The fuel injection device according to any one of claims 2 to 15, wherein the acoustic resonator (2) is arranged separately from the fuel injector (1).
  18. 18. The fuel injection device according to claim 17, wherein the distance between the acoustic resonator (2) and the fuel injector (1) is at least 50mm.
  19. 19. The fuel injection device according to any one of claims 2 to 18, wherein the fuel injector (1) is configured to inject a fuel jet (7) having a cone angle of less than 10 degrees, and the acoustic resonator (2) is arranged at a distance from the fuel injector (1) and is configured to diffuse the fuel jet (7).
  20. 20. The fuel injection device according to any one of claims 2 to 19, wherein the fuel injection device comprises a tube (9) arranged between the fuel injector (1) and the acoustic resonator (2), and the fuel injector (1) is configured to inject the fuel into the tube (9).

Description

Fuel injection device, piston engine, acoustic resonator and method for operating a piston engine Technical Field The present invention relates to a fuel injection device for a piston engine according to claim 1. The invention also relates to a piston engine, an acoustic resonator to be retrofitted to a piston engine and a method of operating a piston engine. Background Large piston engines, such as marine and power plant engines, are typically operated using liquid fossil based hydrocarbon fuels, such as conventional light or heavy fuel oils. Over time, natural gas and other gaseous fuels are increasingly used. Conventional liquid hydrocarbon fuels are typically injected directly into the cylinders. The gaseous fuel may be introduced directly into the main combustion chamber or into the intake passage or cylinder via a prechamber arrangement. In particular, dual fuel engines that can operate with two different fuels can have different injection strategies for the two different fuels. This can be applied to the main fuel and possibly to the pilot fuel. The use of a pilot fuel improves the ignition of the main fuel, which typically occurs via compression ignition. The combustion modes can range from premixed combustion to diffusion combustion, depending generally on the fuel and combustion phasing. There is an increasing demand for engines that can utilize alternative fuels (e.g., hydrogen, ammonia, and methanol) as part of the fuel fraction and preferably as a major part of the fuel fraction. Due to the different properties of different fuels, new solutions for fuel injection are also needed, which generally have a major impact on ignition and combustion phasing. In particular in high speed smaller engines, such as in motor vehicles and machines, spark ignition and pure otto modes may be used. In medium-speed large engines, diesel combustion modes and direct injection into the cylinders may be used. It should be noted that the life of larger, e.g. marine and power plant engines is typically significantly longer than the life of e.g. automotive engines. It is therefore important to find solutions that can be improved to these larger engines, thereby taking advantage of the main, expensive components of these engines, but still improving their performance in terms of efficiency and emissions. This may lead to, for example, solutions in which a direct injection engine needs to be retrofitted later to utilize port fuel injection as part of its fuel injection strategy. In new bio-based fuels, methanol is known to be suitable for compression or spark ignition. However, it is challenging for methanol, especially when methanol is used as the main fuel, to achieve maximum efficiency and minimize emissions. Characteristics of methanol include high heat of vaporization and low saturation pressure. When aiming at premixed combustion, port injection of methanol involves the risk of wall wetting, which refers to the condensation of fuel onto the inlet port or the inner surface of the cylinder liner or onto the surface of the intake valve, due to the high heat of vaporization. This results in variations between different cycles of the combustion process and also creates problems in optimizing engine operation at varying loads and/or speeds. All of these effects reflect the overall fuel efficiency and emissions of the engine. Large piston engines operating at nominal power levels are typically operated using relatively high boost pressures generated by turbochargers. When combined with port fuel injection, high pressure and high air flow rates affect fuel delivery in the inlet manifold and may increase the risk of wall wetting, making optimal and well-controlled port injection more challenging. Wall wetting may result in incomplete combustion and fuel condensing on the cylinder liner may also scour and/or contaminate the lubricating oil. The fuel interacting with the cylinder liner may cause residual accumulation on the liner surface, thereby blocking the cross-hatching formed by honing, resulting in increased fuel consumption. These may lead to premature wear of the relevant engine components and/or to more frequent oil changes and other service demands. To avoid wall wetting or other problems described above, efficient atomization of methanol and other fuels with similar behavior is therefore important both for optimal performance of the engine and to avoid unnecessary service. Disclosure of Invention It is an object of the present invention to provide an improved fuel injection device for a piston engine. It is a further object of the present invention to provide an improved piston engine and acoustic resonator to be retrofitted to a piston engine. It is a further object of the present invention to provide an improved method of operating a piston engine. The fuel injection device according to the present invention includes a fuel injector configured to inject liquid fuel into an inlet passage of an engine, and a member