JP6472503B2 - Fuel valve for a large-sized turbocharged compression ignition two-stroke internal combustion engine, an internal combustion engine using the same, and a method of operating the engine - Google Patents

Description

  The present disclosure particularly provides a fuel valve for injecting fuel into a combustion chamber of a large, turbocharged, two-stroke compression ignition internal combustion engine having a fuel supply system that operates with liquid fuel that is difficult or uncertain to ignite, and a large The present invention relates to a method for injecting liquid fuel, particularly liquid fuel that is difficult or uncertain to ignite, into a combustion chamber of an internal combustion engine of two strokes.

  Large, low speed turbocharged, two stroke compression ignition engines of the crosshead type are typically used in large ship propulsion systems or as prime movers in power plants. These engines are very often operated with heavy oil.

  Recently, large turbocharged two-stroke compression ignition engines are required to be able to handle alternative types of fuel such as gas, methanol, coal slurry, water and oil mixtures, petroleum coke, etc. .

  Some of these alternative fuels, such as water and oil mixtures, can reduce costs and emissions.

  However, the use of a mixture of water in a large, low speed, uniflow, turbocharged, two-stroke internal combustion engine has problems.

  One of these problems is the nature and predictability that these fuels will attempt to ignite when injected into the combustion chamber, both of which are controlled within the engine that is compression ignited. Indispensable to put down. Thus, in existing large, low speed, uniflow, turbocharged, two-stroke internal combustion engines, in order to ensure reliable ignition of properly timed fuel, simultaneously with fuel injection that is difficult or uncertain to ignite, Pilot injection of oil or other ignition fluid is used. This problem is found in some types of fuel that are difficult to ignite, such as a mixture of fuel oil and water.

  Large, low speed uniflow turbocharged two-stroke internal combustion engines are typically used to propel large ocean-going cargo ships, and thus reliability is of paramount importance. The operation of these engines with alternative fuels is still a relatively recent development and the reliability of operation with gas has not yet reached the level of conventional fuels. Thus, all existing large, low speed, two-stroke diesel engines are dual fuel engines that have a fuel system that operates with alternative fuels, such as gaseous fuel, and a fuel system that operates with fuel oil, and therefore with fuel oil. It can operate at full power only when traveling.

  Because the combustion chambers of these engines are large in diameter, they typically have three fuel injectors per cylinder, and these three fuel injectors have an angle of about 120 ° around the central exhaust valve. Separated by Thus, in the case of a dual fuel system, there are three alternative fuel valves per cylinder and three conventional fuel oil valves, so the cylinder top cover is a relatively dense place.

  In existing dual fuel engines, fuel oil valves have been used to provide pilot oil injection during operation with gaseous fuel. These fuel oil valves are sized to enable delivery of the amount of fuel oil needed only to operate the engine at full load with fuel oil. However, the amount of oil injected in pilot injection should be as small as possible to obtain the desired reduction in emissions. Such a small dose with a full-size fuel injection system that can also deliver the large amount required for full load operation poses enormous technical problems and is very likely to be realized in practice. Therefore, in existing engines, the pilot oil dose is greater than desired for a single fuel injection event, particularly at moderate to low loads. Alternatives to additional small injection systems that can handle small pilot volumes are quite complex and costly. In addition, the additional small pilot oil injection valve results in a more dense cylinder top cover.

  EP 3070321 discloses a fuel valve that injects low flash point liquid fuel into the combustion chamber of a large, turbocharged, two-stroke self-igniting internal combustion engine. The fuel valve includes an elongated fuel valve housing having a nozzle having a nozzle, a fuel inlet port in the elongated fuel valve housing for connection to a pressurized liquid fuel source, a hydraulic fluid port in the elongated fuel valve housing, and an elongated An axially displaceable valve needle slidably received in a longitudinal bore in the valve housing, wherein the valve needle is located in the valve seat and a closed position in which the valve needle has a lift from the valve seat A valve needle biased towards the closed position, a fuel chamber surrounding the valve needle and open to the valve seat, and a pump piston received in the first bore, wherein the pump piston A pump piston having a pump chamber in a first bore on one side of the piston, and an actuating piston received in the second bore, wherein the actuating piston is in the second bore on one side of the actuating piston; A pump piston is connected to the working piston for movement with the working piston, a working chamber (85) is connected to the working fluid port, a pump chamber is connected to the fuel chamber, and an outlet and fuel inlet An actuating piston having an inlet connected to the port; a sealing liquid inlet port; and a conduit connecting the sealing liquid inlet port to the first bore to seal the pump piston within the first bore. Have

  In general, it is undesirable to operate with a separate pilot injection of igniting liquid for several reasons. Below 3% of the MCR load, it has been found difficult to obtain reliable injector operation. Secondly, any external ignition that takes place outside the cylinder requires at least a minimum amount of fuel, and the long-term functionality of pilot injection has not been further verified. It is anticipated that a worn fuel pump can degrade pilot injection function. In addition, it is expected that rapid pilot injection profiles may increase fuel system wear.

  Also, some of these fuels have low flash points and pose safety problems. In known fuel valve configurations, due to the needle design, there is always a leak between the shaft of the valve needle and the bore in which the shaft is guided. Therefore, a supply of pressurized sealing liquid “sealing oil” is applied to the gap between the shaft and the bore for both sealing and lubrication purposes. In order to minimize leakage, this gap is kept as small as possible with very narrow tolerances, and such a small gap requires lubrication between the shaft and the bore.

  When the two fluids are mixed, it is difficult to separate the sealing oil and the fuel, thus causing an error in the system. When fuel is detected in the lubricating oil system, the engine shuts down and it is often difficult to troubleshoot the root cause.

  Another safety related problem is low flash point when the engine is not operating with low flash point fuel, for example when the engine is not operating, or is a dual fuel engine operating with another type of fuel. It is a requirement by the classification societies that spot fuel is not allowed to remain in the fuel valve and pipes connected to the fuel valve. Therefore, it is necessary to prepare for purging the fuel valve and the pipe or pipe connected to the fuel valve.

  Another challenge with these low flash point fuels is their relatively poor lubrication properties, which can only be used with very small gaps between the moving parts without applying a lubricant.

  Based on this background, the object of the present application is to provide a fuel valve for a large turbocharged compression ignition two-stroke internal combustion engine that overcomes or at least reduces the above-mentioned problems.

  This object is achieved, according to one aspect, by providing a fuel valve that injects liquid fuel into a combustion chamber of a large, low speed, turbocharged, two-stroke compression ignition internal combustion engine, A nozzle comprising an elongate valve housing having a rear end and a front end, an elongate nozzle body extending from the base to the closed tip, a main bore extending from the base to the closed tip, and a plurality of nozzles connected to the main bore A nozzle, a fuel inlet port in the elongate fuel valve housing for connection to a pressurized liquid fuel source, and a longitudinal needle in the elongate valve housing, disposed at the front end of the elongate valve housing, the base connected to the front end An axially displaceable valve needle that is slidably received in the bore with a gap between the valve needle and the needle bore. Open position, closed position on the valve seat, open position with lift from the valve seat and biased towards the closed position, the valve seat is within the elongated valve housing and the fuel in the valve housing Between the chamber and the outlet port in the front end of the elongated valve housing, the outlet port directly connected to the main bore in the nozzle, the fuel chamber connected to the fuel inlet port, and the gap between the needle bore An axially displaceable valve needle open to the fuel chamber at one end, a lubricant inlet port for connection to a pressurized lubricant source, and a first along the length of the needle bore A lubricating oil supply conduit for connecting the lubricating oil inlet port to the gap at the position, an ignition liquid inlet port for connecting to the pressurized ignition liquid source, and from the first position to the fuel chamber along the length of the needle bore Extends from the igniter inlet port to the fuel chamber or gap at a second location close And a fire fluid conduit.

  An advantage of supplying ignition liquid into the nozzle of a fuel injection valve that injects liquid fuel that is difficult to ignite is that the engine can operate without external pilot injection through a separate pilot valve. Instead, ignition takes place in the nozzle of a fuel valve that injects liquid fuel that is difficult to ignite. The igniting liquid ignites in the combustion chamber within the nozzle, and the initial flame is protected from the combustion chamber, increasing the probability of igniting liquid fuel following or simultaneously with the injection event. As a result, the consumption of the ignition liquid can be significantly reduced. Tests have shown that levels well below 1% of the MCR load are possible.

  For example, by providing an independent supply of igniting fluid separately from the lubricating oil system, the amount of igniting fluid can be controlled more accurately and reliably and the type of igniting fluid can be easily changed . By varying the upstream gap and supply pressure, complete control of the amount of ignition fluid can be obtained without compromising the operation of the sealing oil system. Ignition fluid is no longer limited to system oil. For example, more easily ignited liquids such as diesel oil or DME (dimethyl ether) can be used.

  In a first possible implementation of the first aspect, the ignition fluid conduit extends from the ignition fluid inlet port to the fuel chamber at a location adjacent to the valve seat.

  In a second possible implementation of the first aspect, the ignition fluid conduit extends from the ignition fluid inlet port to the valve seat.

  In a third possible implementation of the first aspect, when the valve needle is located in the valve seat, the ignition fluid conduit to the valve seat is closed by the valve needle.

  In a fourth possible implementation of the first aspect, the main bore is open to the base.

  In a fifth possible implementation of the first aspect, the ignition liquid source has a pressure that is higher than the pressure of the liquid fuel source.

  In a sixth possible implementation of the first aspect, the fuel valve is received in a hydraulic fluid port in an elongated fuel valve housing for coupling to a pressurized working fluid source and in a first bore in the valve housing. A pump piston having a pump chamber in a first bore on one side of the pump piston and an actuating piston received in a second bore in the valve housing. An actuating piston having a working chamber in a second bore on one side of the working piston, the pump piston being coupled to the working piston for movement with the working piston, the working chamber being connected to the working fluid port. Fluidly connected, the pump chamber is connected to the fuel chamber and to an outlet and fuel inlet port via a check valve in an elongated fuel valve housing that prevents flow from the pump chamber to the fuel inlet port. Having sintered to an inlet.

  In a seventh possible implementation of the first aspect, the fuel chamber surrounds the valve needle and is open to the valve seat, the valve seat being disposed between the fuel chamber and the outlet port.

  In an eighth possible implementation of the first aspect, the valve needle is configured to move from a closed position to an open position against a bias when the pressure in the fuel chamber exceeds a predetermined threshold.

  In a ninth possible implementation of the first aspect, the fuel valve comprises a coolant inlet port and a coolant outlet port, and a coolant flow path for cooling the fuel injection valve, particularly the portion of the fuel valve closest to the front end. And further comprising.

  In a tenth possible implementation of the first aspect, the elongate valve housing comprises a front portion coupled to the rear portion, and an axially displaceable valve needle is disposed in the front portion, One bore, a second bore, and a matching longitudinal bore are formed in the rear portion.

  In an eleventh possible implementation of the first aspect, the fuel valve further comprises a conduit connecting the sealing fluid inlet port to the first bore to seal the pump piston within the first bore. .

  According to a second aspect, there is provided a large, low-speed turbocharged two-stroke compression ignition internal combustion engine comprising a fuel valve of any possible implementation thereof according to the first aspect.

  In a first possible implementation of the second aspect, the engine includes a pressurized fuel source having a control pressure Pf, a pressurized lubricant source having a control pressure Ps, and a pressurized ignition liquid source having a control pressure Pif. And further comprising.

  In a first possible implementation of the second aspect, Ps is higher than Pf and Pif is higher than Pf.

  In a first possible implementation of the second aspect, the engine is configured to ignite fuel as it enters the main bore in the nozzle.

  According to a third aspect, there is provided a method of operating a large, low speed, turbocharged, two stroke compression ignition internal combustion engine that supplies pressurized liquid fuel to the engine fuel valve at a first high pressure. The fuel valve has an elongated valve housing having a rear end and a front end, the fuel valve has a hollow nozzle having a plurality of nozzles connecting the interior of the nozzle to a combustion chamber in a cylinder of the engine; A base and an elongate nozzle body, the nozzle being connected at its base to the front end of the elongate valve housing, the nozzle having a closed tip, the nozzle being located proximate the tip, and a second ignition liquid The second high pressure is higher than the first high pressure and the liquid fuel injection is controlled by a displaceable valve needle cooperating with the valve seat on the hollow nozzle, A fuel chamber is placed on top, and the fuel chamber is During the period when the axially displaceable valve needle is located in the valve seat, a continuous flow of ignition fluid is delivered to the fuel chamber, allowing the ignition fluid to accumulate on the valve seat and axially A valve needle that can be displaced in the axial direction by initiating a liquid fuel injection event by lifting the displaceable valve needle from the valve seat and putting the accumulated ignition liquid into the hollow injection nozzle immediately before the liquid fuel Delivers a precise dose of igniting fluid to the valve seat and lifts the axially displaceable valve needle from the valve seat so that the accumulated igniting fluid enters the hollow injection nozzle simultaneously with the liquid fuel Thereby initiating a liquid fuel injection event.

  In a first possible implementation of the third aspect, the liquid fuel ignites in the nozzle with the help of an igniting liquid.

  In a first possible implementation of the third aspect, the nozzle is kept above 300 ° C. throughout the engine cycle.

  Further objects, features, advantages and characteristics of fuel valves and engines according to the present disclosure will become apparent from the detailed description.

  In the following detailed portion of the present description, the present invention will be described in more detail with reference to exemplary embodiments shown in the drawings.

1 is a front view of a large two-stroke diesel engine according to an exemplary embodiment. FIG. FIG. 2 is a side view of the large two-stroke engine in FIG. 1. FIG. 2 is a diagram of a large two-stroke engine according to FIG. 1. 2 is a diagram of an exemplary embodiment for one fuel valve of the engine low fuel system of FIG. 2 is a cross-sectional view of an exemplary embodiment of the fuel system of the engine of FIG. 1 in the upper portion of the cylinder. 4 is an elevation view of a fuel valve for using the engine according to FIGS. 1-3 for an exemplary embodiment. FIG. FIG. 7 is a cross-sectional view of the fuel injection valve shown in FIG. FIG. 7a is an enlarged detail view of the first embodiment of FIG. FIG. 7b is an enlarged detail view of the second embodiment of FIG. FIG. 7c is an enlarged detail view of the third embodiment of FIG. FIG. 7d is an enlarged detail view of the fourth embodiment of FIG. It is sectional drawing from which the low flash point fuel injection valve shown in FIG. 6 differs. FIG. 9 is another cross-sectional view of the low flash point fuel injection valve shown in FIG. 9A is an enlarged detail view of FIG. It is another different sectional drawing of the low flash point fuel injection valve shown in FIG. It is another different sectional drawing of the low flash point fuel injection valve shown in FIG.

  In the following detailed description, a compression ignition internal combustion engine will be described with reference to a large, low speed turbocharged two-stroke internal combustion (diesel) engine in an exemplary embodiment. 1, 2, and 3 show a large, low speed turbocharged two-stroke diesel engine with a crankshaft 42 and a crosshead 43. FIG. 3 shows a diagram of a large, low speed turbocharged two-stroke diesel engine with its intake and exhaust systems. In this exemplary embodiment, the engine has four cylinders 1 in a row. Large, low speed, turbocharged, 2-stroke diesel engines typically have 4-14 cylinders in a row, which are held by the engine frame 13. This engine can be used, for example, as a main engine in ocean-going ships or as a stationary engine for operating a generator in a power plant. The total output of this engine can be in the range of 1,000 to 110,000 kW, for example.

  In this exemplary embodiment, the engine is a two-stroke uniflow type diesel (compression ignition) engine, a scavenging port 19 located in the lower area of the cylinder 1 and a central exhaust valve 4 located in the upper part of the cylinder 1. And have. The scavenging is sent from the scavenging receiver 2 of each cylinder 1 to the scavenging port 19. The piston 41 in the cylinder 1 compresses scavenging, fuel is injected from a fuel injection valve (described in more detail below) in a cylinder cover (described in more detail below), and combustion continues, Exhaust gas is generated. When the exhaust valve 4 is opened, the exhaust gas flows through the exhaust duct associated with the cylinder 1 into the exhaust gas receiver 3, through the first exhaust conduit 18 to the turbine 6 of the turbocharger 5, It flows from the turbocharger 5 through the second exhaust conduit, and flows out from the outlet 29 to the atmosphere via the economizer 28. By means of the shaft, the turbine 6 drives a compressor 9. Fresh air is supplied to the compressor 9 via the air inlet 10. The compressor 9 delivers pressurized scavenging to the scavenging conduit 11. The scavenging conduit 11 is connected to the scavenging receiver 2.

  The scavenging gas in the conduit 11 passes through an intercooler 12 for cooling the scavenging gas. In an exemplary embodiment, the scavenging exits the compressor at about 200 ° C. and is cooled to a temperature of 36-80 ° C. by an intercooler.

  The cooled scavenging proceeds through an auxiliary blower 16 driven by an electric motor 17. The auxiliary blower 16 pressurizes the scavenging air when the compressor 9 of the turbocharger 5 is not delivering sufficient pressure for the scavenging receiver 2, i.e., when the engine is in a low or partial load condition. If the engine load is higher, the turbocharger compressor 9 delivers sufficient compression scavenging, when the auxiliary blower 16 is bypassed via the check valve 15.

  FIG. 4 is a diagram of a liquid fuel valve 50 that includes a liquid fuel source 60 (eg, oil and water fuel, or a low flash point fuel such as methanol), a coolant (oil) source 63. , A lubricating fluid source 57, an ignition fluid source 65, a hydraulic fluid (oil) source 97 via a control valve 96, a purge control valve 98, and a hydraulic fluid control valve 98.

  A conduit 62 leads from the pressurized liquid fuel source 60 to an inlet port in the housing of the liquid fuel valve 50. The conduit 62 may be a double walled conduit and may be formed, for example, by a concentric tube or a tube in a solid blocking material such as the cylinder cover 48. A window valve 61 may be provided in the conduit 62 to allow the fuel valve 50 to be removed from the liquid fuel source 60 so that the fuel valve 50 can be purged from flash point fuel. The window valve 61 is preferably electronically operated and controlled by an electronic control unit. Electronic control valve 96 controls the injection event and purge control valve 98 controls the purge by preventing the check valve from closing.

  FIG. 5 shows the upper part of one of a plurality of cylinders 1 according to an exemplary embodiment. The upper cover 48 of the cylinder 1 includes a plurality (typically two or three) of fuel valves 50 that inject liquid fuel from the nozzle of the fuel valve 50 into the combustion chamber above the piston 41 in the cylinder 1. In this exemplary embodiment, the engine has three liquid fuel valves 50 per cylinder, but it should be understood that a single or two fuel valves 50 may be sufficient depending on the size of the combustion chamber. . The exhaust valve 4 is arranged in the center in the upper cover, and the liquid fuel valve 50 is closer to the cylinder wall.

  In one embodiment (not shown), two or three additional fuel oil valves may be provided in the top cover 48 for operation of the engine with fuel oil. The fuel oil valve is coupled to a high pressure fuel oil source as is well known.

  The portion of the fuel valve 50 that is closest to the nozzle and combustion chamber is cooled in one embodiment using a cooling fluid, such as cooling oil, for which system oil (lubricating oil) can be used. In this specification, the main body of the fuel valve 50 includes a coolant inlet port and a coolant outlet port, and a flow path (not shown) between the inlet port and the outlet port passing through a front portion of the fuel valve 50 body. Is provided. The coolant inlet port is connected via a conduit to a pressurized coolant source 63 such as system oil, and the coolant outlet port is connected via a conduit to a coolant reservoir.

  The body of the fuel valve 50 also includes a hydraulic fluid port for controlling the opening and closing of the fuel valve 50. The control port is connected to the pressurized hydraulic fluid source 97 via a conduit. An electronically controlled control valve 96, preferably a proportional valve, controls the opening and closing of the fuel valve 50, i.e. the pressurized hydraulic fluid source 97 and the hydraulic fluid port in the conduit so as to control the injection event. It is arranged between.

  The body of the fuel valve 50 also includes an ignition fluid inlet port for receiving ignition fluid from a pressurized ignition fluid source 65 at pressure Pif.

  The engine includes an electronic control unit (not shown) that controls the operation of the engine. The electronic control unit is connected to the electronic control valves 96 and 98 and the window valve 61 by signal lines.

  The electronic control unit is configured to accurately time the injection event of the liquid fuel valve 50 and to control the liquid fuel dosage (volume injected per injection event) by the fuel valve 50. The electronic control unit, in one embodiment, is configured to control (rate shaping) the shape of the injection curve. This is because the fuel valve can adapt to such a curve.

  In a low flash point fuel configuration, the electronic control unit opens the window valve 61 to ensure that the supply conduit 62 is filled with pressurized low flash point liquid fuel prior to the start of the fuel injection event. And close. Window valve 61 is closed by the electronic control unit when fuel valve 50 needs to be purged from low flash point fuel.

  FIG. 6 is a perspective view of the fuel valve 50, which controls the elongate valve housing 52, the nozzle 54 attached to the front end of the elongate valve housing 52, the lubricant inlet port 70, and the purge. And a control port 36. The nozzle 54 includes a plurality of nozzle holes 56 dispersed in the nozzle 54 in the radial direction and the axial direction.

7, 8, 9, 10, and 11 show cross-sectional views of a fuel valve 50 for injecting liquid fuel into the combustion chamber 41 of a compression ignition internal combustion engine. The fuel valve 50 has an elongate valve housing 52 that has a rearmost end and a nozzle 54 attached to the front end thereof. The nozzle 54 is a separate object, and the base 46 of the nozzle 54 is attached to the front end of the valve housing 52. The rearmost end of the valve housing 52 includes a plurality of ports including a (purge) control port 36, a hydraulic fluid port 78, an ignition fluid port 67, and a gas leak detection port (not shown) . Rearmost, the fuel valve 50 is spread so as to form a head that protrudes from the cylinder cover 48 when mounted to the cylinder cover 48. In this embodiment, the fuel valve 50 is disposed around the central exhaust valve 4, i.e., relatively close to the wall of the cylinder liner. The elongated valve housing 52 and other components of the fuel injector 50 and the nozzle are made from steel, such as tool steel and stainless steel, in one embodiment.

  The hollow nozzle 54 includes an injection hole 56 connected to a main bore 55 in the nozzle 54, and the injection hole 56 is distributed in the radial direction, and preferably is actually distributed in the nozzle 54. The nozzle holes 56 are close to the closed tip portion 59 in the axial direction, and the radial distribution of the nozzle holes 56 covers a relatively narrow range of about 50 ° in the present embodiment. The radial direction of the nozzle hole 56 is such that the nozzle hole 56 is guided away from the cylinder liner wall. Further, the nozzle 56 is guided in substantially the same direction as the swirling direction of the scavenging in the combustion chamber caused by the inclined configuration of the scavenging port (this swirl is a large uniflow type turbocharged two-stroke internal combustion engine). This is a well-known feature).

  The tip portion 59 of the nozzle 54 is closed, that is, there is no downward nozzle 46. The nozzle 54 is connected at its base 46 to the front end of the valve housing 52, and the main bore of the nozzle 54 opens toward the outlet opening 68 within the front end of the valve housing 52. A valve seat 69 is arranged at the transition between the axial bore forming the outlet opening 68 and the fuel chamber 58.

  An axially displaceable valve needle 61 is slidably received within a narrow gap between the longitudinal bore 64 and the elongated valve housing 52. Lubrication between the axially displaceable valve needle 61 and the longitudinal bore is very important. Here, pressurized lubricant is delivered via a conduit 47 into the gap between the longitudinal bore 64 and the valve needle. The channel 47 connects the gap between the valve needle 61 and the axial bore to the lubricating oil inlet port 70, and the lubricating oil inlet port 70 connects to the pressurized lubricating oil source 57 pressurized at the pressure Ps. Can do. The lubricating oil prevents fuel leakage into the gap between the valve needle 61 and the axial bore when operating with low flash point fuel. Furthermore, the lubricating oil provides lubrication between the valve needle 61 and the axial bore 64. In one embodiment, the pressure of the lubricant source 57 is at least above the supply pressure of the liquid fuel source, but the entire flow in the gap between the pump piston 80 and the first bore 81 is in the pump chamber 82. The maximum pressure in the pump chamber 82 during the injection event can be greatly reduced as long as it is directed in the direction it heads.

  The valve needle 61 has a closed position and an open position. The valve needle 61 includes a conical portion shaped to match the valve seat 69. In the closed position, the conical part of the valve needle is located in the valve seat 69. The conical section has a lift from the valve seat 69 in the open position, and the valve needle 61 is elastically biased toward the closed position by a pre-loaded wrap spring 38. The pre-wound winding spring 38 acts on the valve needle 61 and urges the valve needle 61 toward the closed position where the conical portion is located on the valve seat 69.

  The coil spring 38 is a coil spring received within a spring chamber 88 within the elongated fuel valve housing 52. Cooling oil flows through the spring chamber 88. One end of the wrap spring 38 engages the end of the spring chamber 88 and the other end of the wrap spring 38 engages an enlarged section or flange on the valve needle 61, thereby causing the valve needle Is elastically biased toward the valve seat 69.

  The elongate valve housing 52 includes a fuel inlet port 53 for connection to a pressurized liquid fuel source 60 via a low fuel supply conduit 62. The fuel inlet port 53 is connected to a pump chamber 82 in the valve housing 52 via a conduit 51 and a check valve 74. The check valve 74 (suction valve) is provided in the valve housing 52. Check valve 74 ensures that liquid fuel can flow through conduit 51 to pump chamber 82 but cannot flow in the reverse direction.

  A pump piston 80 is slidably and sealingly disposed within the first bore 81 within the elongated fuel valve housing 52, and within the first bore 81 on one side of the pump piston 80. A pump chamber 82 is located. An operating piston 83 is slidably and sealedly disposed in the second bore 84 in the valve housing 52, and an operating chamber 85 is provided on one side of the operating piston 83 in the second bore 84. To position. The pump piston 80 is connected to the actuating piston 83 so as to move with the actuating piston 83, that is, the pump piston 80 and the actuating piston 83 can slide with their respective bores 81, 84. Note that in this embodiment, pump piston 80 and working piston 83 are implemented as a single unit, but pump piston 80 and working piston 83 can also be separate interconnected objects.

  The working chamber 85 is fluidly connected to the working fluid port 78. The electronic control valve 96 controls the hydraulic fluid port 78 and thereby the pressurized hydraulic fluid entering and exiting the hydraulic chamber 85.

  At the beginning of the injection event, the electronic control unit commands the electronic control valve 96 to allow hydraulic fluid to enter the working chamber 85. The pressurized hydraulic fluid in the working chamber 85 acts on the working piston 83, thereby creating a force that urges the pump piston 80 into the pump chamber 82. Thereby, the pressure of the liquid fuel in the pump chamber 82 increases. In one embodiment, the diameter of the working piston 83 is greater than the diameter of the pump piston 80, so the pressure in the pump chamber 82 is correspondingly higher than the pressure in the working chamber 85, and the working piston 83 and the pump piston The combination of pistons 80 acts as a pressure intensifier.

  One or more channels (conduits) 57 fluidly connect the pump chamber 82 to the fuel chamber 58 and thereby to the valve seat 69 located at the bottom of the fuel chamber. The valve seat 69 faces a fuel chamber 58 that surrounds the valve needle 61. The valve needle 61 is configured to move away from the nozzle 54 to obtain a lift and to move toward the nozzle 54 to reduce the lift. In its open position, the valve needle 61 has a lift from the valve seat 69, whereby liquid fuel travels from the pump chamber 82 to the fuel chamber 58, through the valve seat 69 and through the outlet port 68 in the nozzle 54. Allows flow to main bore 55. The low flash point liquid exits main bore 55 through nozzle 56.

  The valve needle 61 obtains a lift when the pressure of the liquid fuel in the pump chamber 82 exceeds the force of the winding spring 38. Accordingly, the valve needle 61 is configured to open against the bias of the spring 38 when the fuel pressure in the pump chamber 82 (and in the fuel chamber 58) exceeds a predetermined threshold. The pressure in the fuel is caused by the pump piston 80 acting on the low flash point liquid fuel in the pump chamber 82.

  The valve needle 61 is configured to be biased to move toward the nozzle 54 as the conical portion moves toward the valve seat 69. This is because the pump piston 80 does not act on the fuel in the pump chamber 82, the pressure in the liquid fuel decreases, and the closing force of the winding spring 38 applied to the valve needle 61 causes the low flash point liquid applied to the valve needle 61. Occurs when the fuel release force is greater.

  When the electronic control unit ends the injection event, it instructs the electronic control valve 96 to connect the working chamber 85 to the tank. The pump chamber 82 is connected to the pressurized liquid fuel source 60, and the operating piston 83 is moved to the operating chamber 85 until the supply pressure of the low flash point liquid fuel flowing through the check valve 74 reaches the position shown in FIG. Energized in, the pump chamber 82 is completely filled with liquid fuel, so the fuel valve 50 is ready for the next injection event. FIG. 8 shows the position of the pump piston 80 and working piston 83 near the end of the injection event, with the bulk of the pump chamber 82 being empty of liquid fuel.

  The liquid fuel injection event is controlled by the electronic control unit ECU according to the length of the start timing and the length of the stroke of the pump piston 80 (rate shaping). The amount of fuel injected in one injection event depends on the stroke length of the pump piston 80. Accordingly, the hydraulic fluid pressure rises in the working chamber 85 in response to a signal from the electronic control unit.

  At the end of the injection event, the electronic control valve 96 removes the pressure from the working chamber 85 and, due to the force of the pressurized liquid fuel in the pump chamber 82, the second operation until the working piston 83 hits the end of the second bore 85. The pump chamber 82 is completely filled with liquid fuel and the fuel valve 50 is ready for the next injection event.

  In one embodiment (not shown), the fuel valve 50 comprises the form of a plunger intensifier having two different diameters, so that the lubrication pressure is just when it is most needed to provide a high lubrication pressure. A large diameter portion of the plunger facing the chamber having a port connected to the control valve 96 and a conduit of the plunger to increase the lubricating oil pressure during the fuel injection event to ensure that it is high. (Channel) having a larger diameter portion facing the chamber of the port connected to 51 and 47.

  The fuel valve 50 includes a lubricating oil inlet port 70 for connection to a pressurized lubricating oil source, and a first through the lubricating oil inlet port 70 to seal and lubricate the pump piston 80 within the first bore 81. And a conduit 30 extending to one bore 81. In one embodiment, the pressure of the lubricant source 57 is at least as high as the maximum pressure in the pump chamber 82 during the injection event.

  In one embodiment, the fuel valve 50 includes means for selectively allowing flow from the pump chamber 82 toward the fuel inlet port 53 to purge the fuel valve 50. The means for selectively enabling the flow from the pump chamber 82 toward the fuel inlet port 53 includes means for selectively disabling the check function of the check valve 74 (suction valve).

  The valve needle 61 is configured to move from the closed position to the open position against the bias of the winding spring 38 when the pressure in the fuel chamber 58 exceeds a predetermined threshold.

  The elongate valve housing 52, in one embodiment, is capable of receiving heat from the coolant inlet port 45 and coolant outlet port 32 and the fuel injection valve 50, particularly the portion of the fuel valve 50 closest to the front end, such as the nozzle and combustion chamber. And a coolant flow path 44 for cooling the nearest portion. The coolant is, in one embodiment, system lubricant from the engine. In one embodiment, the coolant flow path includes a spring chamber 88 in which the winding spring 38 is received.

  In one embodiment, the elongated valve housing 52 includes a front portion 33 that is coupled to the rear portion 35. An axially displaceable valve needle 61 is disposed in the front portion 33, and a first bore 81, a second bore 84, and a matching longitudinal bore are formed in the rear portion 35.

  The fuel valve 50, in one embodiment, extends longitudinally from the sealing and lubricant inlet port 70 at position P 1 along the length of the longitudinal needle bore 64 that seals the valve needle 61 within the longitudinal needle bore 64. A conduit 47 extending to the directional needle bore 64 is provided. The sealing oil flows from the position P1 through the gap to the small chamber surrounding the winding spring, and flows downward toward the fuel chamber 58. A portion of the ignition liquid that flows to the working chamber 85 is mixed with the cooling oil. This has no substantial effect on the cooling oil.

  In the first embodiment, the portion of the ignition liquid that flows to the fuel chamber 58 is passed through the valve housing 52 from the ignition liquid inlet port 67 by the ignition liquid conduit 66 that extends from the position P1 to the gap near the fuel chamber 58 at the position P2. Contact the pressure of the ignition liquid supplied to the gap. The ignition liquid inlet port 67 is connected to the pressurized ignition liquid source 65. Since the pressure of the sealing oil is higher than the pressure of the ignition liquid, the sealing oil prevents the ignition liquid from flowing back into the sealing oil system and leaking.

  As shown in FIG. 7a, the ignition fluid delivered to the gap via the igniter conduit 66 travels along the axial length of the gap to the fuel chamber 58 to the bottom of the fuel chamber 58, ie, the valve seat 69. The valve needle 61, which accumulates immediately above and is movable in the axial direction, is located in the valve seat 69.

  The size of the gap is strictly controlled and selected so that an appropriate amount of ignition liquid is collected at the bottom of the fuel chamber 58 within the engine cycle when the axially movable valve member 61 is located in the valve seat 69. The A suitable amount of igniting fluid is an amount sufficient to provide a reliable and stable ignition and can be, for example, in the range of 0.1 mg to 200 mg depending on the engine size and load, for example. The size of the gap is related to the characteristics of the igniting liquid, such as viscosity, for example, when the igniting liquid source has a pressure that is a difference that exceeds the pressure of the liquid fuel source, a constant flow of igniting liquid of an appropriate size Selected to be realized.

  Due to the signal from the electronic control unit, the liquid fuel pressure from the fuel chamber 58 rises and the valve needle 61 is lifted from the valve seat 69 and moves from its closed position to its open position. The ignition liquid accumulated at the bottom of the fuel chamber 58 (FIG. 7a) first enters the main bore 55 in the nozzle 54, followed by liquid fuel, ie the liquid fuel pushes the ignition liquid forward and enters the main bore 55. Accordingly, the ignition liquid accumulated in the fuel chamber 58 enters the main bore 55 in the nozzle 54 immediately before the liquid fuel. Immediately prior to the opening of the fuel valve 50, the main bore 55 is filled with a mixture of compressed hot air and residual unburned fuel for compression of the scavenging air in the combustion chamber. Allowing air flow into the main bore 55). Accordingly, immediately after the fuel valve 50 is opened, hot compressed air, ignition liquid, and liquid fuel are present in the main bore 55. This results in the ignition of liquid fuel already in the hollow nozzle 54.

  At the end of the injection event, the electronic control unit removes the pressure from the working chamber 85 and the force of the winding spring 38 causes the valve needle 61 to return to the valve seat 69.

  According to a second exemplary embodiment, which is essentially identical to the first exemplary embodiment described above, the ignition liquid is delivered to the valve seat 69 rather than to the gap. This embodiment is shown with reference to FIG. The ignition fluid conduit 66 is open to the valve seat 69. The opening angle of the conical tip of the valve needle 61 is slightly sharper than the opening angle of the conical valve seat 69, so that the gap between the valve needle tip and the valve seat 69 is narrow. This narrow gap allows ignition fluid 49 to accumulate in the fuel chamber 58 and directly above the valve seat 69 while the valve needle 61 is positioned on the valve seat 69.

  According to a third exemplary embodiment, which is essentially identical to the embodiment described above, the igniting liquid is delivered to the fuel chamber 58. This embodiment is shown with reference to FIG. The igniter conduit 66 is open to the fuel chamber 58, preferably just above or near the valve seat 69. While the valve needle 61 is positioned on the valve seat 69, the ignition liquid 49 accumulates in the fuel chamber 58 on the valve seat 69.

  According to a fourth exemplary embodiment, which is essentially identical to the embodiment described above, the ignition liquid is delivered to the valve seat 69. This embodiment is shown with reference to FIG. The ignition fluid conduit 66 is open to the valve seat 69. The opening angle of the conical tip of the valve needle 61 is substantially the same as the opening angle of the conical valve seat 69, so that when the valve needle 61 is positioned on the valve seat 69, the valve needle 61 is Close the opening of the igniter conduit 66 to The ignition fluid is delivered to the valve seat 69 through an ignition fluid conduit 66 that is open to the valve seat 69 when the valve needle has a lift. In this embodiment, the delivery of the appropriate amount of igniting fluid needs to be done in a short period of time, so that the igniting fluid supply pressure and / or the cross-sectional area of the igniting fluid supply conduit 66 is compared to the embodiment described above. Increase.

  The injection of liquid fuel is controlled by a displaceable valve needle 61 that cooperates with a valve seat 69 on the hollow nozzle 54. The fuel chamber 58 is pressurized with liquid fuel. According to the first, second and third embodiments, during the period in which the valve needle 61 is located in the valve seat 69, a small continuous ignition fluid flow is delivered to the fuel chamber 58 and the ignition fluid 49 is supplied to the valve seat 69. (Embodiment according to FIGS. 7a, 7b and 7c). The fuel injection event is initiated by lifting the axially movable valve needle 61 from the valve seat 69 and putting the accumulated ignition liquid 49 into the main bore 55 in the hollow injection nozzle 54 immediately before the liquid fuel. The liquid fuel is then ignited in the nozzle 54 with the help of ignition liquid.

  In the embodiment of FIG. 7d, the igniting liquid is delivered to the valve seat 69 when the valve needle 61 has a lift so that liquid fuel and igniting liquid are delivered to the main bore in the injection nozzle 45 simultaneously.

  The engine is configured to compression ignite the injected liquid fuel with the aid of igniting liquid without the use of other ignition equipment.

  The engine is configured to ignite liquid fuel upon entering the main bore in nozzle 54.

  In one embodiment, the nozzle 54 is kept above 300 ° C. throughout the engine cycle. In one embodiment, the temperature in the hollow nozzle 54 is about 600 ° C. at the end of the compression stroke.

  In one embodiment, the fuel valve 50 is between the pump chamber 82 and the fuel inlet port 53 to selectively allow flow from the pump chamber 82 to the fuel inlet port 53 for purging the fuel valve 50. A dedicated control valve for fluid connection is provided. This control valve is preferably opened and closed in response to a control signal. In this embodiment, there is no need to provide a means for selectively disabling the check function of the check valve 74.

  In one embodiment, the lubricant source has a control pressure Ps, the liquid fuel source has a control pressure Pf, and Ps is higher than Pf. In this embodiment, the control pressure Ps can be lower than the maximum pressure in the pump chamber 82 during the pump stroke. In this case, the Ps during the pump stroke, the size of the gap, and the maximum pressure in the pump chamber 82 are such that the low flash point liquid fuel enters the gap and the lubricating liquid along a portion rather than all of the length of the pump piston 80. Are selected in an interdependent manner, and the sealing liquid will not leave any low flash point fuel before another pump stroke is performed, but will replace virtually all low flash point fuel in the gap. Therefore, low flash point fuel will not enter the lubricating oil system itself.

  As used in the claims, the term “comprising” does not exclude other elements or steps. It is not excluded that there may be a plurality of configurations that are not specified as being plural. The electronic control unit can fulfill the functions of several means recited in the claims.

  Any reference signs used in the claims shall not be construed as limiting the scope.

  Although the invention has been described in detail for purposes of illustration, such details are for that purpose only, and those skilled in the art will make modifications to the invention without departing from the scope of the invention. It is understood that you can.

Claims (14)

A fuel valve (50) for injecting liquid fuel into a combustion chamber of a large, low-speed turbocharged two-stroke compression ignition internal combustion engine,
An elongated valve housing (52) having a rear end and a front end;
An elongated nozzle body extending from the base (46) to the closed tip (59), a main bore (55) extending from the base (46) to the closed tip (59), and connected to the main bore (55) A nozzle (54) comprising a plurality of nozzles (56),
A nozzle (54) disposed at the front end of the elongated valve housing (52), the base (46) being coupled to the front end;
A fuel inlet port in said elongated has a valve housing (52) for connection to a pressurized liquid fuel source (60) (53),
An axially displaceable valve needle slidably received within a longitudinal needle bore (64) in the elongate valve housing (52) with a gap between the needle bore (64). (61) having a closed position and an open position, located at the valve seat (69) in the closed position, having a lift from the valve seat (69) in the open position, Being energized,
The valve seat (69) is within the elongated valve housing (52) between a fuel chamber (58) in the valve housing (52) and an outlet port (68) in the front end of the elongated valve housing (52). Placed between
The outlet port (68) connects directly to the main bore (55) in the nozzle (54);
The fuel chamber (58) is connected to the fuel inlet port (53);
An axially displaceable valve needle (61) in which the gap is open to the fuel chamber (58) at one end of the needle bore (64);
A lubricant inlet port (70) for connection to a pressurized lubricant source (57);
A lubricant supply conduit (47) connecting the lubricant inlet port (70) to the gap at a first position (P1) along the length of the needle bore (64) ;
An ignition fluid inlet port (67) for connection to a pressurized ignition fluid source (65) ;
In a fuel valve (50) comprising:
A second position closer to the fuel chamber (58) than the first position (P1) along the length of the valve seat (69) or the needle bore (64) from the ignition liquid inlet port (67). A fuel valve comprising an ignition liquid conduit (66) extending to the gap at position (P2) . The opening of the ignition fluid conduit (66) to the valve seat (69) is closed by the valve needle (61) when the valve needle (61) is located in the valve seat (69). The fuel valve according to 1 . The fuel valve according to claim 1 or 2 , wherein the main bore (55) is open to the base (46). The pressure ignition fluid sources (65), wherein a pressure higher than the pressure of the pressurized liquid fuel source (60), a fuel valve according to any one of claims 1 to 3. Pressurized hydraulic fluid source and hydraulic fluid ports of the elongate have a valve housing (52) in for connection to (97) (78),
A pump piston (80) received in a first bore (81) in the valve housing (52), the first bore (81) on one side of the pump piston (80) A pump piston (80) having a pump chamber (82) therein;
An actuating piston (83) received in a second bore (84) in the valve housing (52), into the second bore (84) on one side of the actuating piston (83); An actuating piston (83) having an actuating chamber (85),
The pump piston (80) is coupled to the working piston (83) for movement with the working piston (83);
The working chamber (85) is fluidly connected to the hydraulic fluid port (78);
In the elongated valve housing (52), the pump chamber (82) prevents flow from the pump chamber (82) to the fuel inlet port (53) and an outlet connected to the fuel chamber (58). check valve through (74), having connected an inlet to the fuel inlet port (53), a fuel valve according to any one of claims 1 to 4. The fuel chamber (58) surrounds the valve needle (61) and opens to the valve seat (69), and the valve seat (69) includes the fuel chamber (58) and the outlet port (68). It is disposed between the fuel valve according to any one of claims 1 to 5. The valve needle (61) is configured to move from the closed position to the open position against the bias when the pressure in the fuel chamber (58) exceeds a predetermined threshold. fuel valve according to any one of 6. A coolant inlet port and coolant outlet port, wherein fuel Ryoben (50), in particular the coolant flow path for cooling the part closest to the front end of the fuel valve (50) (44) and further comprising, wherein Item 8. The fuel valve according to any one of Items 1 to 7 . The elongate valve housing (52) comprises a front portion (33) connected to a rear portion (35), and the axially displaceable valve needle (61) is in the front portion (33). is arranged, said valve needle (61) and combine longitudinal bore (64), wherein formed in the front portion (33) within said first bore (81) and said second bore (84) 6. The fuel valve according to claim 5 , formed in the rear part (35). The conduit (30) further connecting the lubricant inlet port (70) to the first bore (81) to seal the pump piston (80) within the first bore. 5. The fuel valve according to 5 . A two-stroke compression ignition internal combustion engine with a turbocharged, large and low-speed operation, comprising the fuel valve (50) according to any one of claims 1 to 10 . Control pressure Pf pressurized liquid fuel source with (60), further comprising pressure-pressure Namerayu source having a control pressure Ps and (57), pressure point fire liquid source having a control pressure Pif and (65), according to claim 11. The organization according to 11 . The engine according to claim 12 , wherein Ps is higher than Pf and Pif is higher than Pf. Engine according to any one of the main bore configured to ignite the liquid fuel as it enters said liquid fuel into (55), according to claim 11 to 13 in said nozzle (54).

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