The present invention relates to a dual fuel injection valve having a pumping nozzle for a diesel engine and a gas engine and, more particularly, to a hybrid fuel injection valve which enables primary injection of primary fuel by using an internal pumping structure instead of using an external pressure pump and uses pressure used for primary fuel injection as pump pressure for secondary fuel injection.
Generally, a conventional diesel engine has one needle valve and one spring, wherein the needle valve is opened when fuel of higher pressure than opening pressure is introduced and is closed when the fuel of lower pressure than the opening pressure is introduced. In this manner, when fuel of high pressure formed in a fuel pump enters to a fuel valve, if the pressure of the fuel in the fuel valve is higher than the opening pressure, the spring lifts the needle valve against a force pressing against the needle valve through pressure of fuel oil, such that the fuel is injected into a cylinder through multiple nozzle holes located on an end terminal of a nozzle.
Such a method consists of one mechanism in which all nozzle holes are opened according to a predefined opening pressure, and thus, after the opening pressure is formed, even if higher pressure is introduced to the fuel valve, injection is only continued through a predefined number of nozzle holes.
Meanwhile, in case of a gas engine, two fuel injection valves, one for a pilot valve and one for a valve for primarily gas, or two needle cylinders are provided to be used, and in order to provide two fuel supply paths corresponding thereto, a pipe line that conforms to the two valves needs to be installed, thereby requiring two governors for timing control, a linkage device, etc.
In the Wartsila-Sulzer approach, when pressure is greater than the opening pressure but fails to form high pressure, fuel flows into the cylinder, rather than being injected into the cylinder through multiple nozzle holes fabricated on the nozzle. Also, even after the fuel injection is finished, a space (SAC volume) between the closed needle valve and the nozzle hole is large such that residue fuel remaining in this space flows into the cylinder, thereby causing the problem as described above.
Also, in the MAN-B&W approach, a needle valve in a slide type is adopted to reduce the SAC volume; however, the MAN-B&W approach has limitation in that pressure above the opening pressure cannot be actively coped with. In other words, the SAC volume is fixed.
Also, in a case of the medium sized engine, the above described MAN-M&W approach and the Wartsila-Sulzer approach are complemented by creating an injection hole to be located near a combustion chamber to a maximum extent in order to reduce the SAC volume, which causes a problem in that durability of a nozzle portion in opening and closing the needle is degraded.
Namely, the above described approaches have disadvantageous in that, as shown in
Also, a fuel injection valve in a dual fuel type as dual fuel injection apparatuses 1, 2 shown in a lower portion of
Therefore, an objective of the present invention is to provide a fuel injection valve in which, by using two kinds of fuel entering into a fuel valve, a warming up and injection of pilot fuel is performed in an initial injection and injection of main fuel is performed subsequently such that subsequent dual fuel is used for combustion, thereby increasing fuel injection performance.
Also, another objective of the present invention is to provide a fuel injection valve in a hybrid structure in which, instead of requiring two kinds of separate pump devices, a piston is pushed to open two injection holes in one pump to press and inject primary fuel, and pressure thereof opens a needle valve of secondary fuel to inject the secondary fuel, thereby increasing fuel efficiency to reduce harmful gas (smoke, NOx).
In accordance with an aspect of the present invention which achieves the above objectives and solves the disadvantages in the prior art, provided is a dual fuel injection valve having a pumping nozzle for a diesel engine and a gas engine, in a fuel injection valve for the diesel engine or the gas engine for injecting fuel to a cylinder, the dual fuel injection valve including a fuel valve block in which a fuel passage to which first and secondary fuel is introduced through a high pressure pipe is formed inside thereof, the first and secondary fuel being the same fuel system or different fuel systems; a cylinder/needle valve which moves upward by a pressure difference of the secondary fuel introduced through the fuel passage formed in the fuel valve block to inject the primary fuel to a pilot nozzle hole; and a main needle valve which, after injecting the primary fuel by pressing the cylinder/needle valve, moves upward by the pressure difference of the secondary fuel introduced through a connected fuel passage to inject the primary fuel to a main nozzle hole.
The present invention is characterized in that the cylinder/needle valve includes a pressing piston head portion formed on an upper portion thereof by groove machining; a primary fuel pressing piston having a lower portion inserted to the pressing piston head portion and a fuel pressing hole formed at a certain point thereof, the primary fuel pressing piston being elastically supported by a primary fuel piston spring; a pressure piston connected to a residue pressure maintaining valve and a fuel main passage pipe through a fuel passage to receive pressure of the secondary fuel and to press an upper portion of the primary fuel pressing piston; and the residue pressure maintaining valve of which upper portion is connected to the fuel passage in order to restore the pressure piston which is pressed for injecting the primary fuel.
The present invention is characterized in that, when the primary fuel cylinder/needle valve is closed, the primary fuel is switched to lower pressure such that the primary fuel is drained outside of the injection valve through a primary fuel drain line via an area of a chamber A, which is a cooling area of the secondary fuel and located at a lower portion of the main needle valve.
The present invention is characterized in that a bush is installed around the main needle valve 143 such that the bush 130 prevents mixing of the primary fuel which is pilot fuel and the secondary fuel which is main fuel introduced to a chamber B 302 and serves as a medium for cooling and heat exchanging high temperature of a main nozzle hole 161 at an area of a chamber A 301.
As described above, the present invention has advantages in that a fuel injection apparatus used in an engine which uses dual fuel does not require two separate pumps and one pumping structure is operated within a valve so as to move two needles in the one pumping structure, thereby enabling pumping at high pressure and enabling pumping dual fuel at high pressure for injection.
Also, the present invention has a significant industrial applicability since the present invention has advantages in that two kinds of subsequent fuel are injected, without mixing, to an inside of a combustion chamber to be combusted such that a combustion pattern using two kinds of fuel, i.e., marine diesel oil (MDO) +heavy fuel oil (HFO) and MDO +gas fuel is achieved, thereby reducing harmful gas (smoke, Nox) within the combustion chamber and improving fuel efficiency.
(100): Nozzle holder
(110): Fuel valve block
(130): Bush
(131): Pilot fuel main passage
(134): Drain line
(135): Needle spring
(139): Primary fuel drain line
(140): Dual hybrid nozzle block
(141): Spring tension adjustment bolt
(142): Spring support
(143): Main needle valve
(160): Pilot nozzle hole
(161): Main nozzle hole
(170): Fuel main passage pipe
(200): Tension adjustment nut
(300): Residual pressure maintaining valve
(501): Pressure piston
(502): Primary fuel pressing piston
(503): Primary fuel pressing piston spring
(504): Fuel pressing hole
(505): Pressing piston head
(506): Cylinder/needle valve
(301): Chamber A
(302): Chamber B
Hereinafter, exemplary embodiments of the present invention will be described herein below with reference to the accompanying drawings. Further, in the following description of the present invention, a detailed description of associated known functions or elements will be omitted when it may make the subject matter of the present invention rather unclear.
Also, in using primary fuel and secondary fuel, instead of using an external high pressure pump or controlling the dual fuel by a control of an electronic apparatus, an internal pumping, which is a main feature of the present invention, is pressed by the secondary fuel to pump and inject the primary fuel, and the injected primary fuel is used to cool high temperature around the secondary fuel.
To this end, the present invention includes a fuel valve block 110 having a fuel passage formed inside thereof, wherein the primary and the secondary fuel is introduced thereto through a high pressure pipe, a nozzle holder 100 surrounding an entire fuel valve, a primary fuel piston spring 503 which operates to move upward or downward according to pressure of the secondary fuel, a needle spring 135, a cylinder/needle valve 506 which is moved upward or downward by the pressure of the secondary fuel to inject the primary fuel, a main needle valve 143 which injects the primary fuel by moving upward or downward according to the pressure of the secondary fuel which has already injected the primary fuel, a pilot nozzle hole 160 which injects the primary fuel which is the pilot fuel to a cylinder located at a lower portion thereof, and a dual hybrid nozzle block 140 on which a main nozzle hole 161 is fabricated, wherein the main nozzle hole 161 injects the secondary fuel which is the main fuel to the cylinder located at the lower portion thereof.
In the present invention having the above configuration, the dual fuel, i.e., fuel such as heavy fuel oil (HFO), marine diesel oil (MDO) used in the diesel engine and gas fuel using a natural gas can be injected from two nozzles within one fuel injection valve such that efficient injection is possible in a case of using fuel systems of the same series, i.e., HFO as the secondary fuel which is the main fuel and MDO as the primary fuel which is the pilot fuel.
Also, when using the dual fuel, the MDO may be used as the primary fuel for ignition and a gas may be used as the secondary fuel which is the main fuel may be used for injection.
Specifically, it can be seen that a spring tension bolt 141 for adjusting pressure of the needle spring 135 installed inside a cylinder axis in which secondary main fuel system elements are installed and a tension adjustment nut 200 for controlling and fixing a tension adjustment state by the spring tension bolt 141 is installed at an upper portion thereof.
The primary fuel used in the present invention stands by at a low pressure through a pilot fuel main passage 131 up to the pilot nozzle hole 160, and this fuel serves to cool around the secondary fuel while being responsible for circulation within the injector.
When the secondary fuel which is the main fuel introduced through a main fuel main passage 170 pushes a pressure piston 501 for pressing the primary fuel (MDO, diesel fuel, etc.) by pressure received from a pump, a primary fuel pressing piston 502 which is a main piston that is supported by the primary fuel piston spring 503 is moved downward to press the primary fuel in the cylinder/needle valve 506 at high pressure such that the cylinder/needle valve 506 is operated by a pressure difference per cross section area to inject the primary fuel through the pilot nozzle hole 160 which is a primary fuel injection hole.
When the injection is completed, the pressure piston 501 which presses the primary fuel needs to be restored, and to this end, pressure is drained from a residue pressure maintaining valve 300 to restore the pressure piston 501.
At the same time, the secondary fuel (HFO, gas, etc.) which is the main fuel, after pushing the pressure piston 501, arrives in an area of a chamber B 302 which is a hole shown in the drawing and stands by up to an entrance of the main nozzle hole 161, and the main needle valve 143 is opened by high pressure to inject the secondary fuel which is the main fuel to the main nozzle hole 161.
Thus, in a dual fuel injection valve using two kinds of fuel comprising main and secondary fuel, the primary fuel which is the pilot fuel receives pressure of the secondary fuel which is the main fuel to form high pressure within the cylinder/needle valve 506 and inject the primary fuel, as is the main feature of the present invention, and then the secondary fuel which finishes pressing the primary fuel provides pressure difference used to open the main needle valve 143 by its own high pressure.
The pilot fuel used herein refers to the marine diesel oil (MDO) which generally has good combustion and injection in the diesel engine and the secondary fuel which is the main fuel refers to the heavy fuel oil (HFO).
Also in a case of the gas engine, fuel such as the MDO is used for ignition when injecting the pilot fuel and the main fuel refers to a gas used for LNG or a general gas engine.
A reference number 505 which has not been described refers to a piston head, a reference number 134 refers to a drain line for discharging leak fuel and air discharged from the residue pressure, and a reference number 142 refers to a spring support.
The illustrated primary fuel flows under general pressure, instead of high pressure, through the pilot fuel main passage 131 as shown in
As illustrated, pressing by the secondary fuel which is the main fuel is performed under high pressure according to a location of the fuel pressing hole 504 which is shown enlarged in
When primary fuel injection is finished, pressure is drained to the residue pressure maintaining valve 300 which restores the pressure piston 501 and the primary fuel pressing piston 502, thereby restoring the piston. At the same time, the primary fuel cylinder/needle valve 506 is closed, and the primary fuel is switched to lower pressure such that the primary fuel is directed to an area of a chamber A 301, which is a cooling area of the secondary fuel and located at a lower portion of the main needle valve 143, to cool the secondary fuel at high temperature, and subsequently, the primary fuel is drained outside of the injection valve through a primary fuel drain line 139.
Also, a bush 130 as illustrated serves as an anti-confused fuel bush which prevents mixing of the primary fuel which is the pilot fuel and the secondary fuel which is the main fuel as well as a medium for cooling and heat exchanging high temperature of the main nozzle hole 161 at the area of the chamber A 301.
The present invention is not limited to particular preferable exemplary embodiments described above and it will be understood by those of ordinary skill in the art that various modifications may be made without departing from the spirit and scope of the present invention as defined by the following claims.
Number | Date | Country | Kind |
---|---|---|---|
10-2010-0063772 | Jul 2010 | KR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/KR10/07436 | 10/28/2010 | WO | 00 | 12/21/2012 |