KR20160059037A

KR20160059037A - Fuel injection pump

Info

Publication number: KR20160059037A
Application number: KR1020140159983A
Authority: KR
Inventors: 박태형
Original assignee: 현대중공업 주식회사
Priority date: 2014-11-17
Filing date: 2014-11-17
Publication date: 2016-05-26

Abstract

A fuel injection pump is disclosed. The fuel injection pump according to the present invention uses a second plunger provided so as to be movable up and down with respect to the first plunger so as to change the volume of the pressure chamber into which the fuel flows and pressurizes, While maintaining the fuel injection amount. Therefore, even when the engine is driven in the low load region, the fuel can be pressurized to a high pressure. Therefore, even in the low load region, the fuel can be pressurized and injected at a high pressure, so that unburned fuel can be suppressed. Therefore, in the low load region, the combustion efficiency can be improved and the harmful substances discharged can be reduced.

Description

[0001] FUEL INJECTION PUMP [0002]

The present invention relates to a fuel injection pump capable of adjusting the injection amount of fuel without reducing the injection pressure of fuel in a low load region.

An engine is an engine that converts heat energy into mechanical one. It refers to a reciprocating engine that moves the piston by igniting the fuel in the combustion chamber and exploding.

A cylinder head of an engine is provided with a fuel injection valve for injecting fuel into a combustion chamber, and the fuel injection valve is supplied with fuel from a fuel injection pump which pressurizes and pressurizes fuel at a high pressure.

The fuel injection pump includes a barrel and a plunger. The barrel serves as a cylinder, and the plunger can be raised and lowered inside the barrel, and is rotatably installed to serve as a piston. The plunger is raised and lowered by a cam of a camshaft connected to a crankshaft of the engine, and is rotated by a linear motion of a rack provided on the outer peripheral surface side of the barrel.

A pressure chamber is formed in the barrel on the upper side of the plunger to pressurize the fuel. When the fuel flows into the pressure chamber, the plunger rises to pressurize the fuel. A spill port communicating with a lower portion of the pressure chamber is formed on a side surface of the barrel.

A discharge port for discharging the fuel in the pressure chamber to the fuel injection valve side is formed in the upper portion of the plunger, and the discharge port is opened and closed by the valve. At this time, the valve is elastically supported on the elastic member to close the discharge port.

Thus, when the pressure of the fuel pressurized by the plunger is larger than the elastic force of the elastic member, the valve moves in a direction to open the discharge port, whereby the fuel pressurized in the pressure chamber is discharged to the fuel injection valve Lt; / RTI >

The plunger has a depression formed at the center of the plunger and a helical surface of the plunger forming the upper portion of the depression to adjust the fuel injection amount.

In detail, as the plunger rises, when the plunger is rotated and positioned so that the lower portion of the helical face communicates with the spill port, fuel in the pressure chamber is pressurized to a high pressure, so that a large amount of fuel is injected . As the plunger rises, when the plunger is rotated and positioned so that the upper portion of the helix surface communicates with the spill port, the fuel in the pressure chamber is pressurized to a low pressure, so that a small amount of fuel is injected.

The conventional fuel injection pump as described above controls the position of the plunger by adjusting the position of the plunger so that the injection pressure of the fuel decreases in a low load region requiring a small amount of fuel. Then, when the fuel is burned in the combustion chamber of the engine, unburned is generated, and a large amount of harmful substances are discharged.

It is an object of the present invention to provide a fuel injection pump capable of solving all the problems of the conventional art as described above.

It is another object of the present invention to reduce the volume of a pressure chamber into which a fuel is injected and pressurize so that a positive amount of fuel can be injected at a high pressure in a low load region, The fuel injection pump may be provided with a fuel injection pump.

In order to achieve the above object, a fuel injection pump according to an embodiment of the present invention is provided with a motion path, a spill port for injecting fuel into the motion path is formed at one side of the side surface, A barrel having a discharge port for discharging the pressurized fuel from the moving path; A first plunger installed to be rotatable in a linear reciprocating motion in the motion path; A first plunger disposed at one end of the first plunger located in the moving path and linearly reciprocating together with the first plunger so as to inject the fuel introduced into the pressure chamber formed between one end surface of the first plunger and the moving path, And the second plunger is capable of adjusting the volume of the pressure chamber while linearly reciprocating with respect to the first plunger.

The fuel injection pump according to the embodiment of the present invention uses a second plunger provided so as to be able to move up and down with respect to the first plunger to change the volume of the pressure chamber into which the fuel flows and pressurizes, Regulates the injection amount of the fuel while maintaining the high pressure. Therefore, even when the engine is driven in the low load region, the fuel can be pressurized to a high pressure. Therefore, even in the low load region, the fuel can be pressurized and injected at a high pressure, so that unburned fuel can be suppressed. Therefore, in the low load region, the combustion efficiency can be improved and the harmful substances discharged can be reduced.

1 is a schematic view showing an engine to which a fuel injection pump according to an embodiment of the present invention is applied.
2 is a sectional view of a fuel injection pump according to an embodiment of the present invention;
3 is a cross-sectional view showing a state in which the second plunger shown in FIG. 2 is raised.
Fig. 4 is a perspective view of the second plunger and the support member shown in Fig. 2; Fig.

It should be noted that, in the specification of the present invention, the same reference numerals as in the drawings denote the same elements, but they are numbered as much as possible even if they are shown in different drawings.

Meanwhile, the meaning of the terms described in the present specification should be understood as follows.

The word " first, "" second," and the like, used to distinguish one element from another, are to be understood to include plural representations unless the context clearly dictates otherwise. The scope of the right should not be limited by these terms.

It should be understood that the terms "comprises" or "having" does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

It should be understood that the term "at least one" includes all possible combinations from one or more related items. For example, the meaning of "at least one of the first item, the second item and the third item" means not only the first item, the second item or the third item, but also the second item and the second item among the first item, Means any combination of items that can be presented from more than one.

The term "above" means not only when a configuration is formed directly on top of another configuration, but also when a third configuration is interposed between these configurations.

Hereinafter, a fuel injection pump according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a schematic configuration of an engine to which a fuel injection pump according to an embodiment of the present invention is applied.

As shown, the engine according to an embodiment of the present invention may include an engine block 110 and a cylinder head 120 coupled to each other. The engine block 110 and the cylinder head 120 may be connected to each other through a combustion chamber 111 may be formed.

Most of the space of the combustion chamber 111 can be formed inside the engine block 110 and the cylinder head 120 can be coupled to the engine block 110 to seal one side of the combustion chamber 111. [

A cylinder liner 113 may be installed on the inner circumferential surface of the engine block 110 forming the combustion chamber 111 and a piston 115 may be installed on the cylinder liner 113 to reciprocate linearly. The piston 115 is inserted into the cylinder liner 113 through the other side of the combustion chamber 111 and the other side of the combustion chamber 111 can be sealed by the piston 115.

Thus, as the fuel flows into the combustion chamber 111 formed between the piston 115 and the cylinder head 120 and is compressed and exploded and expanded, the piston 115 can reciprocate linearly. Then, the crankshaft 117 connected to the piston 115 via the connecting rod (not shown) can be rotated by the linear reciprocating motion of the piston 115. Most of the rotational force of the crankshaft 117 is transmitted to the clutch side through the flywheel and a part of the rotational force is transmitted to the other device including the fuel injection pump 200 according to the present embodiment .

The fuel injection pump 200 according to this embodiment will be described with reference to Figs. 2 to 4. Fig. FIG. 2 is a cross-sectional view of a fuel injection pump according to an embodiment of the present invention, FIG. 3 is a cross-sectional view showing a state where the second plunger shown in FIG. 2 is lifted, It is a perspective view of the member.

As shown, the fuel injection pump according to the present embodiment may include a housing 210 forming an outer appearance.

Hereinafter, referring to the direction and the direction of other components including the housing 210, the upper surface and the direction of the housing 210 are referred to as "upper surface and upper side" Face and direction are referred to as " lower and lower sides ".

A barrel 220 may be installed on the inner upper portion of the housing 210.

A moving path 221 may be formed along the longitudinal direction of the barrel 220 and a lower end of the moving path 221 may be communicated with the lower outside of the barrel 220 on the inner center side of the barrel 220. A spill port 223 for introducing the fuel into the movement path 221 may be formed on the side surface of the barrel 220 and a fuel injection port 223 may be formed on the upper end side of the barrel 220, A discharge port 225 for discharging the fuel to the fuel injection valve (not shown) may be formed.

An inlet hole (not shown) for supplying fuel to the space between the housing 210 and the barrel 220 where the spill port 223 is located may be formed in the housing 210.

The first plunger 230 can be installed in the motion path 221 such that the upper side of the first plunger 230 can be inserted and linearly reciprocated 1 (see FIG. 1). At this time, a portion of the moving path 221 positioned above the upper end surface of the first plunger 230 is a pressure chamber 221a into which the fuel flows and is pressurized.

Therefore, when the upper end surface of the first plunger 230 is positioned below the spill port 223 due to the lowering of the first plunger 230, the fuel can flow into the pressure chamber 221a, When the upper end surface of the first plunger 230 passes through the spill port 223 and is positioned above the spill port 223 by the rise of the first plunger 230, The fuel can be pressurized.

A valve (not shown) for opening and closing the discharge port 225 may be provided on the upper surface of the barrel 220, and the valve may be elastically supported by an elastic member (not shown) to close the discharge port 225. Therefore, if the pressure of the fuel pressurized in the pressure chamber 221a is larger than the elastic force of the elastic member, the discharge port 225 is opened by the valve, so that the high- May be pumped into the fuel injection valve.

The lower portion of the first plunger 230 may be exposed to the lower side of the barrel 220 and may be located in the lower inner portion of the housing 210 and the lower portion of the first plunger 230 and the lower portion of the housing 210 An elastic member 250 for elastically supporting the first plunger 230 as a lowering point may be provided between the first and second plungers.

A finishing member 260 may be installed on the upper end surface of the housing 210 and the upper end surface of the barrel 220.

The amount of fuel supplied to the combustion chamber 111 can be adjusted according to the load applied to the engine. That is, when a high load is applied to the engine, a large amount of fuel must be supplied to the combustion chamber 111, and when a low load is applied, a small amount of fuel must be supplied to the combustion chamber 111. However, if the injection pressure of the fuel supplied to the combustion chamber 111 is lowered when the engine is driven in the low load region, a large amount of harmful substances may be generated in the combustion of the fuel due to the unburned fuel.

The fuel injection pump 200 according to the present embodiment can change the volume of the pressure chamber 211a into which the fuel is injected and compressed to adjust the injection amount of the fuel without reducing the injection pressure of the fuel even in the low load region .

The lower end of the second plunger 240 can be inserted into the upper end of the first plunger 230 inserted in the motion path 211 and the second plunger 240 can be inserted into the upper end of the first plunger 230. [ As shown in Fig. Then, as shown in FIGS. 2 and 3, the volume of the pressure chamber 211a is changed by the lifting and lowering of the second plunger 240. FIG.

At this time, when the engine is driven in the high load region, the second plunger 240 may be lowered and positioned at the bottom dead center as shown in FIG. Therefore, since the volume of the pressure chamber 211a is relatively large, a large amount of fuel flows into the pressure chamber 211a, so that a large amount of fuel can be discharged to the combustion chamber 111. [

When the engine is driven in the low load region, as shown in Fig. 4, the second plunger 240 may be raised and positioned at the position of the top dead center. Then, since the volume of the pressure chamber 211a is relatively small, a small amount of fuel flows into the pressure chamber 211a, so that a small amount of fuel can be discharged to the combustion chamber 111. [

3, the first plunger 230 moves in the same manner, so that the fuel introduced into the pressure chamber 211a is supplied to the first plunger 230 by the first plunger 230. In other words, in the high load region shown in Fig. 2 and the low load region shown in Fig. Respectively. However, since a large amount of fuel flows in the high load region shown in FIG. 2, a large amount of fuel is discharged to the combustion chamber 111 side, and a small amount of fuel flows in the low load region shown in FIG. 3, Is discharged to the combustion chamber 111 side. Therefore, even in the low load region, the injection amount of the fuel can be adjusted without reducing the injection pressure of the fuel.

The first plunger 230 can be rotated by the linear movement of a rack 217 provided between the lower end side of the barrel 220 and the housing 210. The rack 217 can be rotated by the number of revolutions of the engine, And can be connected to the governor (not shown) for controlling the injection amount of the fuel, so that the fuel can be linearly moved.

The second plunger 240 can be moved up and down by the rotation of the first plunger 230. A support hole 232 into which the second plunger 240 is inserted is formed inside the upper end side of the first plunger 230 so that the first plunger 230 can be moved up and down by the rotation of the first plunger 230 And an inner circumferential surface of the support hole 232 and an outer circumferential surface of the second plunger 240 may be formed with threaded lines (not shown) interdigitating with each other. Therefore, the second plunger 240 can be moved up and down as the first plunger 230 rotates in the forward and reverse directions.

The second plunger 240 should not rotate together with the first plunger 230 in order for the second plunger 240 to move up and down when the first plunger 230 rotates. A support member 227 may be provided on the barrel 220 and a lower portion of the support member 227 may be provided on the second plunger 230. In order to prevent the second plunger 240 from rotating together with the first plunger 230, Can be inserted into the guide path (242) formed in the guide member (240).

The fuel injection pump 200 according to the present embodiment changes the volume of the pressure chamber 211a into which the fuel is injected and pressurized by using the second plunger 240 installed to be movable up and down with respect to the first plunger 230 Adjust the amount of fuel injected. Therefore, even when the engine is driven in the low load region, the fuel can be pressurized to a high pressure. Therefore, even in the low load region, the fuel can be pressurized and injected at a high pressure, so that unburned fuel can be suppressed. Therefore, in the low load region, the combustion efficiency can be improved, and the harmful substances discharged can be reduced.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be clear to those who have knowledge of. Therefore, the scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention.

210: Housing
220: Barrel
230: first plunger
240: second plunger

Claims

A spill port for introducing the fuel into the movement path is formed at one side of the side surface and a discharge port for discharging the fuel pressurized by the movement path is formed at one end surface, ;
A first plunger installed to be rotatable in a linear reciprocating motion in the motion path;
A first plunger disposed at one end of the first plunger located in the moving path and linearly reciprocating together with the first plunger so as to inject the fuel introduced into the pressure chamber formed between one end surface of the first plunger and the moving path, And a second plunger for pressurizing,
Wherein the second plunger linearly reciprocates with respect to the first plunger to adjust the volume of the pressure chamber.

The method according to claim 1,
A support hole is formed in one end side of the first plunger,
The second plunger is inserted into the support hole,
Wherein the inner circumferential surface of the support hole and the outer circumferential surface of the second plunger are formed with threaded lines mutually engaged so that the second plunger can reciprocate linearly as the first plunger rotates in the forward and reverse directions, Pump.

3. The method of claim 2,
Wherein the barrel is provided with a support member for preventing rotation of the second plunger by rotation of the first plunger.