KR101921490B1 - A fuel valve and method for injecting a liquid fuel into a combustion chamber of large compression-igniting turbocharged two-stroke internal combustion engine - Google Patents

Abstract

A fuel valve 50 for injecting liquid fuel into the combustion chamber of a large low speed two stroke turbocharged compression ignition internal combustion engine comprises a elongated valve housing 52 having a rear end and a front end, A main bore 55 extending from the base 46 to the tip 59 closed and a plurality of nozzle holes 56 connected to the main bore 55. The main bore 55, And a base 51 disposed at the front end of the elongated valve housing 52 and having a nozzle 54 connected to the front end and a fuel inlet 54 in a elongated valve housing 52 for connection to a source of pressurized liquid fuel, A valve needle 61 slidably received in the longitudinal bore 77 in the elongated valve housing 52 and axially displaceable in a gap between the valve needle 61 and the needle bore 64, A valve needle 61 having a closed position and an open position, A valve needle 61 placed on the flange 69 and rising from the seat 69 in an open position and a valve needle 61 deflected toward the closed position, a fuel chamber 58 in the valve housing 52, A seat 69 disposed in the elongated valve housing 52 between the outlet ports 68 at the front end of the housing 52, an outlet port 68 directly connected to the main bore 55 in the nozzle 54, A fuel chamber 58 connected to the port 53, a clearance opening to the fuel chamber 58 at one end of the needle bore 64, a lubricant inlet port 78 for connection to a source 57 of pressurized lubricant, A lubricant supply conduit 76 for connecting the lubricant inlet port 70 to the gap at the first position Pl along the length of the needle bore 64 and an ignition fluid for connecting to the source of pressurized ignition fluid 65 Is closer to the fuel chamber 58 than the fuel chamber 58 or first position Pl from the inlet port 67 and the ignition liquid inlet port 67. [ It includes ignition fluid conduit (66) extending along the length of the needle bore (64) to the gap between the second position (P2).

Description

FIELD OF THE INVENTION The present invention relates to a fuel valve for injecting liquid fuel into a combustion chamber of a large compression ignition turbocharged two-stroke internal combustion engine, and a fuel valve and method for injecting liquid fuel into a combustion chamber of a large compression ignition turbocharged two-

This disclosure relates to a fuel supply system that operates with a liquid fuel, particularly a fuel valve and a liquid fuel that inject fuel into the combustion chamber of a large two-stroke turbocharged compression ignition internal combustion engine that is difficult or unreliable to ignite liquid fuel, To a method of injecting a liquid fuel which is difficult or unreliable to ignite into the combustion chamber of an ignition internal combustion engine.

A large low speed turbocharged two stroke compression ignition engine of the crosshead type is commonly used as a propulsion system for a large ship or as a prime mover of a power plant. These engines are very common when operating with heavy oil.

Recently, there has been a demand to use alternative types of fuels such as gas, methanol, coal slurry, water-oil mixture, petroleum coke and other fuels for large turbocharged two stroke compression ignition engines.

Some alternative fuels, such as water-oil mixtures, are likely to reduce costs and emissions (emissions).

However, there are some problems with the use of water mixtures in large, low-speed, uniflow turbocharged two-stroke internal combustion engines.

One of these problems is the readiness and predictability of these fuels for compression ignition on injection into the combustion chamber, and both preparation and predictability are essential for control in a compression ignition engine. Therefore, the existing large-scale low-speed single-flow turbocharged two-stroke internal combustion engine uses pilot injection of oil or other ignition fluid at the same time as injection with difficult or uncertain fuel ignition for reliable and timely ignition of fuel. This problem raised in ignition is also present in some types of fuels, such as fuel oil-water mixtures.

Large, low speed, single-flow turbocharged two-stroke internal combustion engines are generally used for propulsion of large cargo ships operating in the ocean, and therefore reliability is paramount. Operating these engines as alternative fuels has only recently been developed and the reliability of gaseous fuels has not yet reached the level of conventional fuels. Accordingly, the conventional large-sized low-speed two-stroke diesel engine is a dual fuel engine capable of operating only the fuel flow channel at the maximum output, with both a fuel system operating with an alternative fuel such as gas fuel and a fuel system operating with the fuel flow channel.

Because these engine combustion chambers are large in diameter, generally three fuel injection valves per cylinder are provided and are separated at an angle of about 120 ° around the central exhaust valve. Thus, the dual fuel system has three alternative fuel valves and three conventional fuel oil valves per cylinder, and the top cover of the cylinder is a relatively crowded place.

In conventional dual fuel engines, fuel oil valves are being used to provide pilot oil injection while operating as gaseous fuel. This fuel oil valve is dimensioned to deliver the amount of fuel oil necessary to operate the engine at maximum load on the fuel flow path. However, the amount of oil injected into the pilot injection should be as small as possible to achieve the desired emission reduction. The small amount of injection using a full-size fuel injection system capable of delivering large quantities for operation at full load results in considerable technical difficulties and is very difficult to achieve in practice, so the pilot oil capacity is limited in conventional engines, At low loads, more than the desired amount per fuel injection event is being injected. Finding an alternative to an additional small injection system that can handle small pilot volumes is complex and costly. In addition, the additional small pilot oil injection valve makes the top cover of the cylinder much more congested.

EP 3070321 discloses a fuel valve for injecting a low flash point liquid fuel into a combustion chamber of a large two stroke turbocharged self-ignition internal combustion engine. The fuel valve comprises a elongated valve housing having a nozzle with a nozzle hole, a fuel inlet port in the elongated fuel valve housing for connection to a source of pressurized liquid fuel, a working fluid port in the elongated valve housing, An axially displaceable valve needle slidably received in the longitudinal bore of the valve housing, a valve needle having a valve needle in the closed position lying on the valve seat and an open position in which the valve needle is lifted from the valve seat, a valve needle biased toward the closed position, A pump chamber surrounding the needle and opening to the valve seat, a pump piston contained in a first bore having a pump chamber on a first bore on one side of the pump piston, a pump piston having a working chamber on a second bore on one side of the working piston 2 Operational piston housed in the bore, connected to the operating piston and moved together An operating chamber 85 connected to the working fluid port, a pump chamber having an inlet connected to the fuel chamber and an inlet connected to the fuel inlet port, a sealing fluid inlet port, a sealing member for sealing the pump piston in the first bore, And a conduit connecting the liquid inlet port to the first bore.

It is generally not desirable to operate as a separate ignition pilot injection for several reasons. It has proven difficult to achieve stable injector operation at less than 3% of the MCR load. Second, external ignition outside the cylinder requires at least a minimum amount of fuel, and the long-term function of the pilot injection is not further validated. If the fuel pump wears down, the pilot injection function may deteriorate. It is also expected that rapid pilot injection characteristics can increase wear of the fuel system.

Some of these fuels have safety problems due to their low flash point. In the construction of the known fuel valve, there is always leakage between the shaft of the valve needle and the bore through which the shaft is guided due to the design of the needle. Therefore, the gap between shaft and bore is supplied with pressurized sealing fluid 'sealing oil' for both sealing and lubrication purposes. To minimize leakage, keep clearance as small as possible with very small tolerances and lubrication between shaft and bore.

It is difficult to separate the sealant oil and the fuel if they are mixed, thereby causing a system malfunction. If fuel is detected in the lubricating oil system, it can result in the engine stopping, and often it is difficult to solve the root cause.

Other safety-related problems include that the low-flash point fuel remains in the tubing following the fuel valve and the fuel valve, for example, for a dual fuel engine in which the engine does not operate at low flash point fuel, There is a request from the classification society not to allow. Therefore, preparations must be made to purify the tubing or piping leading to the fuel valve and the fuel valve.

Another problem with these low flash point fuels is that the relatively low lubrication properties prevent the use of very small gaps between moving parts without the use of lubricants.

In view of the above, it is an object of the present invention 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 by providing a fuel valve for injecting liquid fuel into a combustion chamber of a large low-speed two-stroke turbocharged compression ignition internal combustion engine according to the first aspect, the fuel valve comprising a elongate valve housing having a rear end and a front end, A plurality of nozzle holes extending from the base to a closed tip and a plurality of nozzle holes connected to the main bore, the base being disposed at a front end of the elongate valve housing, the base having a front end A fuel inlet port in a elongated valve housing for connecting to a source of pressurized liquid fuel, a shaft slidably received in a longitudinal needle bore in a elongated valve housing having a clearance between the valve needle and the needle bore, An axially displaceable valve having a closed position and an open position, A needle disposed in a elongated valve housing between the fuel chamber in the valve housing and the outlet port at the front end of the elongated valve housing; a valve needle positioned on the valve seat in the closed position and rising from the valve seat in the open position and deflected toward the closed position; An outlet port directly connecting to the main bore of the nozzle, a fuel chamber connected to the fuel inlet port, a gap opening to the fuel chamber at one end of the needle bore, a lubricant inlet port for connecting to a source of pressurized sealing oil, A lubricant supply conduit connecting the inlet port to the gap in a first position along the length of the needle bore, an ignition fluid inlet port for connecting to a source of pressurized ignition fluid, and an ignition fluid inlet port to the chamber Ignition fluid conduit extending to the gap in the second position along the length of the closer needle bore It should.

The advantage of supplying the ignition fluid to the nozzles of the fuel injection valve which injects liquid fuel which is difficult to ignite is that the engine can be operated without external pilot injection via a separate pilot valve. Instead, ignition occurs inside the nozzle of the fuel valve which injects fuel which is difficult to ignite. The ignition liquid is ignited from inside the chamber of the nozzle where the initial flame is protected from the combustion chamber and is more likely to ignite the liquid fuel following or at the same time during the injection event. This significantly reduces the consumption of ignition fluid. Test results show that levels far below 1% of the MCR load are possible.

By supplying an independent ignition liquid separated from the lubricating oil system, for example, the injection quantity of the ignition liquid can be controlled more accurately and reliably, and the type of ignition liquid can be easily changed. Complete control of the amount of ignition fluid is obtained by varying the upstream gap and the supply pressure without compromising the function of the sealing fluid system. The ignition liquid is no longer limited to the system oil. For example, diesel oil or a liquid that is more easily ignited, such as DME (dimethyl ether), can be used.

According to a first possible embodiment of the first aspect, the ignition liquid conduit extends from the ignition inlet port to the fuel chamber at a location adjacent the seat.

According to a second possible embodiment of the first aspect, the ignition liquid conduit extends from the ignition inlet port to the seat.

According to a possible third embodiment of the first aspect, the ignition liquid conduit for the seat is closed by a valve needle if the valve needle is placed on the seat.

According to a possible fourth embodiment of the first aspect, the main bore is open to the base.

According to a possible fifth embodiment of the first aspect, the pressure of the ignition source is higher than the pressure of the liquid fuel source.

According to a possible sixth embodiment of the first aspect, the fuel valve comprises a hydraulic fluid port in a elongated valve housing for connecting to a source of pressurized hydraulic fluid, a pump chamber in the valve housing with a pump chamber in a first bore on one side of the pump piston, A pump piston received in the first bore, and a working piston received in a second bore in the valve housing together with the second bore operating chamber on one side of the working piston, wherein the pump piston is moved together with the working piston , The working chamber is fluidly connected to the working fluid port and the pump chamber is connected to the fuel inlet port via an outlet connected to the fuel chamber and a check valve in the elongated valve housing preventing flow from the pump chamber to the fuel inlet port And has an inlet that is open to the outside.

According to a possible seventh embodiment of the first aspect, the fuel chamber surrounds the valve needle and the opening for the valve seat, and the valve seat is disposed between the fuel chamber and the outlet port.

According to a possible eighth embodiment of the first aspect, the valve needle is configured to move from the closed position to the open position for deflection when the pressure in the fuel chamber exceeds a predetermined threshold.

According to a ninth possible embodiment of the first aspect, the fuel valve further comprises a fuel injection valve, in particular a coolant inlet port for cooling the portion closest to the front end of the fuel valve, a coolant outlet port and a coolant channel.

According to a possible tenth embodiment of the first aspect, the elongated valve housing includes a front portion connected to the rear portion, the axially displaceable valve needle disposed on the front portion, the first bore, the second bore, and the matching longitudinal direction The bore is formed in the rear portion.

According to a possible eleventh embodiment of the first aspect, the fuel valve further comprises a conduit connecting the sealing fluid inlet port to the first bore for sealing the pump piston in the first bore.

According to a second aspect, there is provided a large low-speed two-stroke turbo-charged compression ignition internal combustion engine comprising a fuel valve according to the first aspect of its possible embodiment.

According to a first possible embodiment of the second aspect, the engine comprises a pressurized fuel supply source having a controlled pressure (Pf), a pressurized lubricant supply source with a controlled pressure (Ps) And an ignition liquid supply source.

According to a second possible embodiment of the second aspect, Ps is higher than Pf and Pif is higher than Pf.

According to a possible third embodiment of the second aspect, the engine is configured to ignite the fuel at the time of fuel entry into the main bore inside the nozzle.

According to a third aspect, there is provided a method of operating a large two stroke low speed turbocharged compression ignition internal combustion engine, the method comprising: supplying a pressurized liquid fuel at a first high pressure to a fuel valve of the engine; A fuel valve having a nozzle having a plurality of nozzle holes for connecting the inside of the nozzle to a combustion chamber in the engine cylinder, a nozzle including a base and a long nozzle body, A nozzle connected to a front end of the valve housing, a nozzle having a nozzle closed with a nozzle hole arranged near the tip, supplying an ignition liquid to the fuel valve at a second high pressure, a second high pressure higher than the first high pressure, Controlling the injection of the liquid fuel into the valve needle cooperating with and displaceable with the seat on the nozzle, placing the fuel chamber on the seat, Transferring the continuous flow of ignition fluid to the fuel chamber, causing the ignition liquid to accumulate on the seat during the period that the axially displaceable valve needle lies on the seat, and transferring the axially displaceable valve needle to the seat So that the accumulated ignition liquid is allowed to flow into the hollow injection nozzle immediately in front of the liquid fuel or precisely the precise injection amount of the ignition liquid is applied to the sheet And displacing the axially displaceable valve needle from the seat to initiate a liquid fuel injection event thereby causing the accumulated ignition fluid to enter the hollow fuel injection nozzle simultaneously with the liquid fuel.

According to a first possible embodiment of the third aspect, the liquid fuel ignites in the nozzle with the aid of an ignition liquid.

According to a second possible embodiment of the third aspect, the nozzle is maintained at a temperature above 300 [deg.] C throughout the engine cycle.

Additional objects, features, advantages and characteristics of the gaseous fuel valve and engine according to the present disclosure will become apparent from the detailed description.

In the following detailed description of the present disclosure, the present invention will be described in more detail with reference to the embodiments shown in the following figures.
1 is a front view of a large two-stroke diesel engine according to an exemplary embodiment,
2 is a side view of the large two-stroke engine of Fig. 1,
Figure 3 is a schematic representation of a large two-stroke engine according to Figure 1,
Figure 4 is a graphical representation of an example embodiment of the engine fuel system of Figure 1,
Figure 5 is a cross-sectional view of a schematic representation of an example embodiment of a cylinder top fuel system of the Figure 1 engine,
FIG. 6 is an elevation view of a fuel valve for using an engine according to an exemplary embodiment of FIGS. 1 to 3. FIG.
FIG. 7 is a sectional view of the fuel injection valve shown in FIG. 6,
Figure 7a shows a first embodiment of the enlarged detail view of Figure 7,
Figure 7b shows a second embodiment of the enlarged detail view of Figure 7,
Fig. 7C shows a third embodiment of the enlarged detail view of Fig. 7,
FIG. 7D shows a fourth embodiment of the enlarged detail view of FIG. 7,
8 is another cross-sectional view of the low flash point fuel injection valve shown in FIG. 6,
FIG. 9 is another cross-sectional view of the low flash point fuel injection valve shown in FIG. 6,
FIG. 9A shows an enlarged detail view of FIG. 9,
10 is another cross-sectional view of the low flash point fuel injection valve shown in FIG. 6,
11 is another cross-sectional view 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 two stroke, low speed turbocharging internal combustion (diesel) engine of exemplary embodiments. Figures 1, 2 and 3 illustrate a large low speed turbocharged two stroke diesel engine with a crankshaft 42 and a crosshead 43. Figure 3 shows a schematic representation of a large low speed turbocharged two stroke diesel engine with intake and exhaust systems. In this exemplary embodiment, the engine has four cylinders 1 that have been heated. A large low speed turbocharged two stroke diesel engine is typically supported by an engine frame 13 and has four to fourteen cylinders for heat. This engine can be used, for example, as a main engine of a ship operating on the ocean or as a stationary engine for generator operation of a power plant. The total output of the engine may range, for example, from 1,000 to 110,000 kW.

Stroke diesel (compression ignition) engine having a scavenge port 19 in the lower region of the cylinder 1 and a central exhaust valve 4 at the upper end of the cylinder 1 in this example embodiment. The scavenge passes from the scavenging accommodating portion 2 to the scavenging port of the individual cylinder 1. The piston 41 in the cylinder 1 compresses the air and the fuel is injected from a fuel injection valve (described in further detail below) in the cylinder cover (described in further detail below) . When the exhaust valve 4 is opened, the exhaust gas flows to the exhaust gas receiving portion 3 through the exhaust duct coupled with the cylinder 1, and then flows through the first exhaust conduit 18 to the turbocharger 5 After flowing to the turbine 6, the exhaust gas is discharged via the second exhaust conduit 7 via the economizer 28 to the outlet 29 and into the atmosphere. Through the shaft, the turbine (6) drives the compressor (9) supplied with fresh air via the air inlet (10). The compressor (9) transfers the compressed air to the scavenge conduit (11) leading to the scavenge receiving portion (2).

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

If the compressor 9 of the turbocharger 5 does not deliver sufficient pressure to the scavenging receiver 2, that is, under low or partial load conditions of the engine, the scavenged scavenging air flows into the electric motor 17 And passes through the auxiliary blower 16 driven by the blower. At a higher engine load, the turbocharger compressor 9 delivers a sufficiently compressed scavenger then the auxiliary blower 16 is bypassed via the check valve 15.

Fig. 4 is a schematic view showing a state in which a supply source 60 (for example, a fuel such as oil-water or a low-flash point fuel such as methanol), a supply source 57 for a cooling liquid, a supply source 65 for an ignition liquid, A purge control valve 98, and a liquid fuel valve 50 connected to the working fluid control valve 98. The fluid fuel valve 50 is connected to a supply source 97 of the working fluid (oil)

The conduit 62 leads from the source of the pressurized liquid fuel 62 to the inlet port in the housing of the liquid fuel valve 50. The conduit 62 may be a double wall conduit formed by a concentric tube or tube within the solid block 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 disconnected from the source of liquid fuel 60 so that the fuel valve 50 can be purged from the low flash point fuel. The window valve 61 is preferably electronically actuated and controlled by an electronic control device. The electronic control valve 96 controls the injection event, and the purge control valve 98 prevents the check valve from being closed to control purge.

5 shows the top of one of the plurality of cylinders 1 according to an exemplary embodiment. The top cover 48 of the cylinder 1 is provided with a plurality (generally two or three) of fuel valves (not shown) for injecting liquid fuel from the nozzles of the fuel valve 50 into the combustion chamber on the piston 41 in the cylinder 1. [ 50). In this exemplary embodiment, there are three liquid fuel valves 50 per cylinder in the engine, but one or two fuel valves 50 per cylinder may be sufficient depending on the size of the combustion chamber. The exhaust valve 4 is disposed at the center of the top cover, and the liquid fuel valve 50 is disposed closer to the cylinder wall.

In the embodiment (not shown), two or three additional fuel oil valves may be provided in the top cover 48 for operating the fuel flow passage engine. The fuel oil valve is connected to a source of high pressure fuel oil in a well known manner.

The front portion of the fuel valve 50 closest to the nozzle and closest to the combustion chamber is cooled using a cooling liquid such as cooling oil in which the system oil (lubricating oil) can be used. Here, the body of the fuel valve 50 is provided with a coolant inlet port and a coolant outlet port, and a flow passage (not shown) is provided between the inlet port and the outlet port through the front portion of the fuel valve 50 main body. The coolant inlet port is connected to a pressurized coolant source 63 such as system oil via a conduit and the coolant outlet port is connected to the coolant reservoir via a conduit.

Further, the body of the fuel valve 50 is provided with a working fluid port for controlling the opening and closing of the fuel valve 50. [ The control port is connected to a source of pressurized working fluid 97 via a conduit. An electronic control valve 96, preferably a proportional valve, is disposed in the conduit between the working fluid port and the working fluid supply source 97, which is pressurized to control the opening and closing of the fuel valve 50, i. .

The main body of the fuel valve 50 is also provided with an ignition liquid inlet port for receiving the ignition liquid from the pressurized ignition liquid supply source 65 with the pressure Pif.

The engine is provided with an electronic control device (not shown) for controlling the operation of the engine. The signal line connects the electronic control device to the control valve (96, 98) and the window valve (61).

The electronic control device is configured to set the injection event timing of the liquid fuel valve 50 accurately and control the injection amount of the liquid fuel (the injected volume per injection event) with the fuel valve 50. [ In the embodiment, the electronic control unit is configured to control the shape of the injection curve (speed type) because the fuel valve 50 can adapt to this curve.

 In a configuration using low flash point fuel, the electronic control device opens and closes the window valve 61 to allow the supply conduit 62 to be filled with the low flash point liquid fuel prior to the start of the fuel injection event. The window valve 61 is closed by the electronic control device when the fuel valve 50 needs to be purged from the low flash point fuel.

Figure 6 shows a fuel delivery system comprising a elongated valve housing 52, a nozzle 54 attached to the front end of elongated valve housing 52, a lubricant inlet port 70 and a fuel Fig. The nozzle 54 is provided with a plurality of nozzle holes 56 radially and axially distributed above the nozzle 54.

Figures 7, 8, 9, 10 and 11 show cross-sectional views of the fuel valve 50 for injecting liquid fuel into the combustion chamber 41 of a compression ignition internal combustion engine. The fuel valve 50 has a elongated valve housing 52 with a rear end and a nozzle 54 attached to the front end thereof. The nozzle 54 is a separate body attached with the base 46 at the front end of the valve housing 52. A plurality of ports are provided at the rear end of the valve housing 52 including a (purge) control port 36, a working fluid port 78, an ignition fluid port 67 and a gas leak detection port (not shown) , And to the gas detection conduit 34. The rear end is enlarged to form a head projecting from the cylinder cover 48 when the fuel valve 50 is mounted on the cylinder cover 48. [ In the present embodiment, the fuel valve 50 is disposed relatively close to the periphery of the central exhaust valve 4, that is, the wall of the cylinder liner. Other components of the elongated valve housing 52 and the fuel injection valve 50 as well as the nozzle are made of steel such as, for example, tool steel and stainless steel in the embodiment.

The nozzle 54 is provided with a nozzle hole 56 connected to the main bore 55 of the nozzle 54 and the nozzle hole 56 is distributed radially and preferably substantially over the nozzle 54. The nozzle hole 56 is axially close to the closed tip 59 and the radial distribution of the nozzle hole 56 spans a relatively narrow range of about 50 degrees in the present embodiment. The radial direction of the nozzle hole 56 is directed in the direction in which the nozzle hole 56 is away from the wall of the cylinder liner. Further, the nozzle hole 56 is oriented in the same direction as the desired swirl direction in the combustion chamber by the inclined configuration of the scavenge port (this swirl is characteristic of the swirl type large two-stroke turbocharged internal combustion engine).

The tip 59 of the nozzle 54 is closed. That is, the tip 59 does not have the nozzle hole 46 directed downward. The nozzle 54 is connected to the front end of the valve housing 52 with the base 46 and the main bore of the nozzle 54 opens toward the outlet opening 68 at the front end of the valve housing 52. The valve seat 69 is disposed at the transition between the axial bore forming the outlet opening 68 and the fuel chamber 58.

The axially displaceable valve needle 61 is slidably received in the narrow clearance of the longitudinal bore 64 in the elongated valve housing 52 and is axially displaceable between the valve needle 61 and the longitudinal bore 64. [ Lubrication is important. Here, the pressurized lubricant is transferred to the gap between the longitudinal bores 64 of the valve needle 61 via the conduit (channel) 47. The channel 47 connects a clearance between the valve needle 61 and the axial bore to the lubricant inlet port 70 and may in turn be connected to a source of lubricating oil 57, which is pressurized and at a pressure Ps. The lubricating oil prevents leakage of fuel to the gap between the valve needle (61) and the axial bore when operating with low flash point fuel. The lubricating oil also provides lubrication between the valve needle 61 and the axial bore 64. The pressure of the lubricant supply 57 is higher than the supply pressure of at least the liquid fuel as long as the total flow of the clearance between the pump piston 80 and the first bore 81 is toward the pump chamber 82, May be much lower than the maximum pressure of the pump chamber 82 during the injection event.

The valve needle 61 has a closed position and an open position. The valve needle (61) is provided with a conical portion in a shape matching the valve seat (69). In the closed position, the conical portion of the valve needle 61 rests on the valve seat 69. The conical portion is lifted from the valve seat 69 in the open position and the valve needle 61 is resiliently deflected toward the closed position by the pretensioned helical spring 38. [ The cactus helical spring 38 acts on the valve needle 61 to deflect the valve needle 61 toward the closed position where the conical portion rests on the seat 69.

The helical spring 68 is a helical wire spring received in the spring chamber 96 in the elongated valve housing 52. The cooling oil flows through the spring chamber 88. One end of the helical spring 38 engages with the end of the spring chamber 88 and the other end of the helical spring 38 engages with the extension or flange on the valve needle 61 to urge the valve needle into the valve seat 69 And pressurized to be elastic.

The elongated valve housing 52 has a fuel inlet port 53 for connecting to a source of pressurized liquid fuel 60 via a fuel supply conduit 62. The fuel inlet port 53 is connected to the pump chamber 82 in the valve housing 52 via the conduit 51 and the check valve 89. A check valve 74 (intake valve) is provided inside the valve housing 52. The check valve 74 prevents the liquid fuel from flowing into the pump chamber 82 through the conduit 51 but not in the opposite direction.

The pump piston 80 is slidably mounted in the first bore 81 of the elongated valve housing 52 with the pump chamber 82 within the first bore 81 on one side of the pump piston 80, . The operating piston 83 is slidably and sealingly disposed on the second bore 84 of the valve housing 52 with the operating chamber 85 in the second bore 84 on one side of the operating piston 83 do. The pump piston (80) is connected to the operating piston (83) and moves together. In other words, the pump piston 80 and the operation piston 83 can slide simultaneously with the respective bores 81 and 84. In this embodiment, the pump piston 80 and the operation piston 83 are formed as a single body. It should be noted, however, that the pump piston 80 and the actuating piston 83 can be separate bodies interconnected.

The operation chamber 85 is fluidly connected to the operation liquid port 78. The electronic control valve 96 controls the flow of the working fluid to and from the working fluid port 78 and into and out of the working chamber 85.

At the start of the injection event, the electronic control device commands the electronic control valve 96 to allow the working fluid to enter the operating chamber 85. The working fluid pressurized in the working chamber 85 acts on the working piston 83 to generate a force for pushing the pump piston 80 into the pump chamber 82. As a result, the pressure of the liquid fuel in the pump chamber 82 rises. The diameter of the working piston 83 is greater than the diameter of the pump piston 80 so that the pressure in the pump chamber 82 is correspondingly higher than the pressure in the operating chamber 85, The engagement of the pump piston (80) acts as a pressure booster.

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 58. The valve seat 69 faces the fuel chamber 58 surrounding the valve needle 61. The valve needle 61 is configured to move away from the nozzle 54 to gain lift and toward the nozzle 54 to reduce lift. The valve needle 61 is allowed to flow from the pump chamber 82 to the fuel chamber 58 by ascending from the seat 69 in the open position and to pass through the valve seat 69 through the outlet port 68, The bore 55 is reached. The low flash point liquid leaves the main bore 55 through the nozzle hole 56.

The valve needle 61 rises when the pressure of the liquid fuel in the pump chamber 82 exceeds the force of the helical spring 38. The valve needle 61 is configured to open against the bias of the helical spring 38 when the pressure of the fuel within the pump chamber 82 (and the fuel chamber 55) 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 biased to move toward the nozzle 54 and the conical portion is configured to move to the valve seat 69. This means that if the pump piston 80 no longer acts on the fuel in the pump chamber 82 and the closing force of the helical spring 38 on the valve needle 61 is greater than the opening force of the low flash point fuel on the valve needle, Is decreased.

When the electronic control device ends the injection event, the electronic control device commands the electronic control valve 96 to connect the operation chamber 85 to the tank. The pump chamber 82 is connected to a source of pressurized liquid fuel 60 and the supply pressure of the low flash point liquid fuel flowing via the check valve 89 is such that the pump chamber 82 is completely filled with liquid fuel The operating piston 83 presses the operating piston 83 into the operating chamber 85 until the fuel valve 50 reaches the position shown in Fig. 7 in a state ready for the next injection event. 8 shows the positions of the pump piston 80 and the operation piston 83 at the end of the injection event in which the liquid fuel is depleted in the main portion of the pump chamber 80. Fig.

The injection event of the liquid fuel is controlled by the electronic control unit (ECU) through the length of the operation timing and the stroke length (flow rate formation) of the pump piston 82. The amount of fuel injected at one injection event is determined by the stroke length of the pump piston 80. [ Therefore, the operating fluid pressure rises in the operation chamber 85 in accordance with the signal of the electronic control unit.

The electronic control unit 96 removes the pressure from the operating chamber 85 and the force of the pressurized liquid fuel in the pump chamber 82 causes the working piston 83 to move to the end of the second bore 85 And push it back into the second bore 85 until it touches it.

In the embodiment (not shown), the fuel valve 50 includes two pressure booster types of different diameter plungers, the large diameter valve 96 of the plunger faces the chamber with the port connected to the control valve, (Channels) 51 and 47 to maintain the lubrication pressure exactly higher when it is most needed to raise the lubricant pressure during a fuel injection event to provide a higher lubrication pressure, .

The fuel valve 50 is provided with a lubricant inlet port 70 for connecting to a pressurized lubricant supply source and a lubricant inlet port 70 for sealing and lubricating the pump piston 80 in the first bore 81, And a conduit 30 extending to one bore 81. In an embodiment, the pressure of the lubricant supply 57 is high enough to at least approximate the maximum pressure in the pump chamber 82 during the injection event.

In an embodiment, the fuel valve 50 includes means for selectively permitting flow from the pump chamber 82 toward the fuel inlet port 53 to purge the fuel valve 50. The means for selectively permitting flow from the pump chamber 82 toward the fuel inlet port 53 includes means for selectively deactivating the non-return function of the non-return valve 74 (intake valve).

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

The elongated valve housing 52 in the embodiment includes a coolant inlet port 45, a coolant outlet port 32 and a fuel injection valve 50, in particular a fuel valve 50 portion closest to the row of nozzles and the combustion chamber, And a cooling liquid flow path 44 for cooling the cooling liquid flow path 44. In an embodiment, the coolant is a system lubricant for the engine. In an embodiment, the cooling fluid flow path includes a spring chamber 88 in which a helical spring 38 is received.

The elongated valve housing 52 in the embodiment includes a front portion 33 connected 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.

Fuel valve 50 is adapted to seal valve needle 61 in longitudinal needle bore 64 from the sealing and lubricant inlet port 70 along the length of longitudinal needle bore 64, (64). The seal fluid flows through the gap from the position P1 into both the chamber surrounding the upper helical spring and the fuel chamber 58 below. The portion of the ignition fluid that flows into the operating chamber 74 is mixed with the cooling oil. This has no substantial effect on the cooling oil.

The ignition liquid portion flowing into the fuel chamber 58 extends from the ignition liquid inlet port 67 through the valve housing 52 to a clearance at the P2 position closer to the fuel chamber 58 than the P1 position The pressure of the ignition liquid supplied to the gap by the ignition liquid conduit 45 is satisfied. The ignition liquid inlet port (67) is connected to the pressurized ignition liquid supply source (65). Because the pressure of the sealing oil is higher than the pressure of the ignition liquid, the sealing oil prevents the ignition fluid from leaking back into the sealing oil system.

The ignition liquid transferred to the gap via the ignition liquid conduit 66 travels along the axial extension of the gap to the fuel chamber 58 and accumulates directly on the bottom of the fuel chamber 58, The valve needle 61 movable in the axial direction is placed on the seat 69 as shown in Fig. 7A.

The dimension of the clearance is precisely controlled and selected such that an appropriate amount of ignition fluid is collected at the bottom of the fuel chamber 58 during an engine cycle in which an axially movable valve member 61 rests on the seat 69. A suitable amount of ignition fluid may be in an amount sufficient to produce a reliable and stable ignition, for example, from 0.1 mg to 200 mg, depending on the engine size and load, for example. The dimensions of the crevices are chosen in relation to the characteristics of the ignition fluid, such as viscosity, so that a constant flow of ignition fluid of the appropriate scale is achieved when the pressure of the ignition source is greater than the pressure of the liquid fuel source.

Depending on the signal of the electronic control unit ECU, the liquid fuel pressure rises in the fuel chamber 58 and the valve needle 61 ascends from the seat 69 when moving from the closed position to the open position. The ignition liquid accumulated in the bottom of the fuel chamber 58 (Fig. 7A) first enters the main bore 55 in the nozzle 54, and then enters the liquid fuel. That is, the liquid fuel pushes the ignition liquid from the front into the main bore 55. Therefore, the ignition liquid accumulated in the combustion chamber 58 enters the main bore 55 of the nozzle 54 immediately before the liquid fuel. Just before the fuel valve 50 is opened, the main bore 55 is filled with a mixture of hot air and residual unburned fuel, which is compressed due to scavenging in the combustion chamber (the nozzle hole 56 extends from the combustion chamber to the main bore 55) Allowing air flow). Therefore, immediately after opening of the fuel valve 50, high-temperature compressed air, ignition liquid, and liquid fuel are present in the main bore 55. Thereby leading to the liquid fuel ignition already inside the nozzle 54.

At the end of the injection event, the electronic control unit removes the pressure from the operating chamber 74, causing the valve needle 61 to return to the seat 69 by the force of the helical spring 66.

According to the second embodiment, which is essentially the same as the first embodiment described above, the ignition liquid is instead passed to the seat 69 instead of the gap. This embodiment is described with reference to Fig. 7B. The igniter liquid conduit 66 is open to the seat 69. The opening angle of the conical tip of the valve needle 61 is slightly more acute than the opening angle of the conical seat 69 and therefore there is a narrow gap between the tip of the valve needle 61 and the valve seat 69. This narrow gap allows the ignition fluid 49 to accumulate in the fuel chamber 58 immediately above the valve seat 69 while the valve needle 61 rests on the seat 69.

According to the third embodiment, which is essentially the same as the above-described embodiments, the ignition liquid is transferred to the fuel chamber 58. [ This embodiment is described with reference to Fig. 7C. The igniter fluid conduit 66 is open to the fuel chamber 58, preferably directly above or adjacent to the seat 69. The ignition liquid 49 is accumulated in the fuel chamber 58 on the valve seat 69 while the valve needle 61 is placed on the seat 69. [

According to the fourth embodiment, which is essentially the same as the above-described embodiments, the ignition liquid is transferred to the seat 69. This embodiment is described with reference to Fig. 7D. The igniter liquid conduit 66 is open to the seat 69. The opening angle of the conical tip of the valve needle 61 is substantially equal to the opening angle of the conical seat 69 so that if the valve needle 61 is placed on the valve seat 69, And closes the opening of the ignition liquid conduit 66. The ignition liquid is transferred to the valve seat 69 through the ignition liquid conduit 66 which opens to the valve seat 69 when the valve needle 61 is lifted. The supply pressure of the ignition liquid and / or the cross-sectional area of the ignition liquid supply conduit 66 is increased in comparison with the embodiments described above, since a proper amount of ignition fluid must be delivered in a short time in this embodiment.

The injection of the liquid fuel is controlled by a displaceable valve needle 61 cooperating with the seat 69 on the nozzle 54. The fuel chamber 58 pressurizes with liquid fuel. During the time when the valve needle 61 is placed on the seat 69 in the embodiment according to Figs. 7a, 7b and 7c, a small continuous flow of ignition liquid is introduced into the fuel chamber (not shown) according to the first, second and third embodiments 58 and the ignition liquid is accumulated on the seat 69. [ The fuel injection event begins by lifting the axially movable valve needle 61 from the seat 69 so that the accumulated ignition liquid enters the main bore 55 of the hollow injection nozzle 54 just in front of the liquid fuel do. The liquid fuel then ignites the interior of the nozzle 54 with the aid of the ignition fluid.

7D, when the valve needle 61 rises, the ignition liquid is transferred to the valve seat 69 to transfer the liquid fuel and the ignition liquid to the main bore of the injection nozzle 45 at the same time.

The engine is configured to compress ignite the injected liquid fuel without using any other ignition device with the help of the ignition liquid.

The engine is configured to ignite the liquid fuel upon entry of the main bore within the nozzle 54. [

In an embodiment, the nozzle 54 is maintained above 300 [deg.] C over the entire engine cycle. In the embodiment, the temperature inside the nozzle 54 is about 600 DEG C at the end of the compression stroke.

The fuel valve 50 is provided with a dedicated control valve at the fluid connection between the pump chamber 82 and the fuel inlet port 53 to supply fuel from the pump chamber 82 to the fuel inlet 50 for purging of the fuel valve 50. [ Lt; / RTI > to the port 53, as shown in FIG. It is preferable that the control valve is opened or closed in accordance with a control signal. In this embodiment, it is not necessary to provide a means for selectively deactivating the non-return function of the check valve 74. [

In an embodiment, the pressure of the lubricating oil supply is controlled pressure Ps, the pressure of the source of liquid fuel is controlled pressure Pf, and Ps is higher than Pf. In this embodiment, the controlled pressure Ps may be lower than the maximum pressure of the pump chamber 82 during the pump stroke. In this case, the size of the clearance during the pump stroke and the maximum pressure in the pump chamber 82 are selected interdependently so that the low flash point liquid fuel enters the gap and replaces the lubricant along a portion that is not all of the length of the pump piston 80 , The sealing fluid substantially replaces all low flash point fuels in the gap before another pump stroke occurs, such that the remaining low flash point fuel does not penetrate the low flash point fuel into the lubricant system itself.

The term " comprising "used in the claims does not exclude other elements or steps. The term "one" or "one" as used in the claims does not exclude a plurality. The electronic control device can perform the functions of various means described in the claims.

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

Although the present invention has been described in detail for the purpose of illustration, it is to be understood that such detail is solely for that purpose and may be modified by those skilled in the art without departing from the scope of the present invention.

Claims (18)

A fuel valve (50) for injecting liquid fuel into a combustion chamber of a large low-speed two-stroke turbocharged compression ignition internal combustion engine,
A elongated valve housing (52) having a rear end and a front end;
A elongated nozzle body extending from the base 46 to the tip 59 closed and a main bore 55 extending from the base 46 to the closed tip 59, A nozzle 54 including a plurality of nozzle holes 56;
The nozzle (54) disposed at the front end of the elongated valve housing (52) with the base (46) connected to the front end;
A fuel inlet port (53) in said elongated valve housing (52) for connection to a source of pressurized liquid fuel (60);
A valve needle (61) slidably received and axially displaceable in said longitudinal needle bore (64) in said elongated valve housing (52) with a clearance between a valve needle (61) and a needle bore (64) The valve needle 61 having a closed position and an open position and resting on the seat 69 in the closed position and rising from the seat 69 in the open position and biased toward the closed position, (61);
The seat (69) disposed within the elongated valve housing (52) between the fuel chamber (58) in the elongated valve housing (52) and the outlet port (68) in the front end of the elongated valve housing );
The outlet port (68) directly connected to the main bore (55) in the nozzle (54);
The fuel chamber (58) connected to the fuel inlet port (53);
The gap opening to one end of the needle bore (64) with respect to the fuel chamber (58);
A lubricant inlet port 70 for connection to a pressurized lubricant supply 57;
A lubricant supply conduit (47) connecting said lubricant inlet port (70) to said clearance in a first position (P1) along the length of the needle bore (64);
An ignition fluid inlet port 67 for connecting to a source of pressurized ignition fluid 65; And
Extends from said ignition liquid inlet port (67) to said chamber or said gap in a second position (P2) along the length of said needle bore (64) closer to said fuel chamber (58) The ignition fluid conduit (66) being connected to the ignition plug.
The method according to claim 1,
Wherein the igniter liquid conduit extends from the ignition liquid inlet port to the fuel chamber at a location adjacent the seat.
The method according to claim 1,
Characterized in that the igniter liquid conduit (66) extends from the ignition liquid inlet port (67) to the seat (69).
The method of claim 3,
Characterized in that the opening of the ignition liquid conduit (66) with respect to the seat (69) is closed by the valve needle (61) when the valve needle (61) .
5. The method according to any one of claims 1 to 4,
And the main bore (55) opens to the base (46).
The method according to claim 1,
Characterized in that the source (65) of the ignition liquid has a pressure which is higher than the pressure of the source (60) of the liquid fuel.
The method according to claim 1,
A working fluid port (78) of said elongated valve housing (52) for connecting to a source of pressurized hydraulic fluid (60);
The pump piston (80) received in the first bore (81) in the elongated valve housing (52) with a pump chamber (82) in a first bore (81) on one side of the pump piston (80);
The working piston 83 received in the second bore 84 in the elongated valve housing 52 together with the working chamber 85 in the second bore 84 on one side of the working piston 83;
The pump piston (80) connected to the operating piston (83) and moving together;
Said operating chamber (85) fluidly connected to said working fluid port (78); And
An outlet connected to the fuel chamber (58) through a check valve (74) in the elongated valve housing (52) preventing flow from the pump chamber (82) to the fuel inlet port (53) And a pump chamber (82) having an inlet connected to a port (53).
The method according to claim 1,
The fuel chamber 58 surrounds the valve needle 61 and the opening for the seat 69 so that the seat 69 is disposed between the fuel chamber 58 and the outlet port 68 Features a fuel valve.
The method according to claim 1,
Wherein the valve needle (61) is configured to move from the closed position to the open position against a bias when the pressure in the fuel chamber (58) exceeds a predetermined threshold.
The method according to claim 1,
Further comprising a coolant inlet port, a coolant outlet port, and a coolant flow passage (44) for cooling a portion of the fuel injection valve (50) closest to the front end portion.
8. The method of claim 7,
The elongated valve housing 52 includes a front portion 33 connected to the rear portion 35, valve needle 61 disposed in the front portion 33 and displaceable in the axial direction, , The second bore (84) and the matching longitudinal bore formed in the rear portion.
8. The method of claim 7,
Further comprising a conduit (30) connecting the lubricant inlet port (70) to the first bore (81) to seal the pump piston (80) in the first bore (81) (50).
A large-low-speed two-stroke turbo-charged compression ignition internal combustion engine according to claim 1, comprising a fuel valve (50).
14. The method of claim 13,
A pressurized fuel supply source 60 having a controlled pressure Pf, a pressurized lubricant supply source 57 having a controlled pressure Ps and a pressurized ignition fluid supply source 65 having a controlled pressure Pif Speed, two-stroke turbocharged compression ignition internal combustion engine.
15. The method of claim 14,
Wherein Ps is higher than Pf and Pif is higher than Pf.
14. The method of claim 13,
And ignites the fuel when fuel is injected into the main bore (55) inside the nozzle (54).
A method of operating a large two stroke low speed turbocharged compression ignition internal combustion engine,
Supplying a first high-pressure, pressurized liquid fuel to the fuel valve (50) of the engine;
The fuel valve (50) having a elongated valve housing (52) having a rear end and a front end; And
The fuel valve 50 having the nozzle 54 with a plurality of nozzle holes 56 connecting the interior 55 of the nozzle 54 to the combustion chamber in the cylinder 1 of the engine, The nozzle 54 connected to the elongated valve housing 52 together with the base 46 and the nozzle hole 56 are connected to the tip 59 Said nozzle (54) having said tip (59) closed closely disposed,
Supplying a second high-pressure ignition liquid to the fuel valve (50), wherein the second high pressure is higher than the first high pressure;
Controlling the injection of the liquid fuel to the valve needle (61) cooperating with and displaceable with the seat (69) on the nozzle (54);
And a fuel chamber (58) disposed above the seat (69)
Pressurizing the fuel chamber (58) with the liquid fuel; And
Transferring a continuous flow of ignition fluid to the fuel chamber (58) and ignition liquid accumulating on the seat (69) during the period during which the axially displaceable valve needle (61) , And raising the axially displaceable valve needle (61) from the seat (69) to initiate a liquid fuel injection event, wherein the ignition liquid stored in the nozzle (54) immediately before the liquid fuel Entering;
When the valve needle (61) displaceable in the axial direction is lifted, the injection amount of the ignition liquid is accurately transmitted to the seat (69), and the valve needle (61) displaceable in the axial direction from the seat And causing the ignition liquid to be injected into the nozzle 54 at the same time as the liquid fuel. How it works.
18. The method of claim 17,
Characterized in that the liquid fuel ignites the interior of the nozzle (54) with the aid of the firing liquid.

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