KR20120090452A - High presure fuel pump for direct injection type gasoline engine - Google Patents

Abstract

PURPOSE: A pressure fuel pump for a direct injection gasoline engine is provided to improve the performance of improving pulsations of fuel by maintaining the fast response property of a damper. CONSTITUTION: A pressure fuel pump for a direct injection gasoline engine comprises a damper unit(20). The damper unit comprises a damper cover(21), a lower guide(22), a damper(23), and an upper guide(24). A lower part of the damper cover is opened to be connected to an upper part of a connection portion(10). A plurality of first movable grooves(211) is formed on an inner upper surface of the damper cover. The lower guide is formed into a circular ring shape, and inserted into the connection portion. A first flow path is formed in the lower guide at a constant interval. The damper is settled inside the lower guide. The upper guide is placed above the damper. A second flow path is formed in the upper guide at the constant interval.

Description

High pressure fuel pump for direct injection gasoline engines {HIGH PRESURE FUEL PUMP FOR DIRECT INJECTION TYPE GASOLINE ENGINE}

The present invention relates to a high-pressure fuel pump for a direct injection gasoline engine, and more particularly, a direct injection gasoline engine for supplying to the injector by compressing the gasoline engine to high pressure so as to directly inject the gasoline fuel into the cylinder after inhaling and compressing air. It relates to a high pressure fuel pump for use.

Gasoline Direct Injection technology is being developed to improve the fuel economy and performance of gasoline engines. Compared to the combustion process of a conventional gasoline engine which is powered by the intake / compression / ignition / explosion / exhaust process of an air / fuel mixture, the direct injection gasoline engine inhales and compresses only air and then burns the fuel. Will be sprayed. This method is similar to the compression ignition method of a diesel engine.

Therefore, the direct injection gasoline engine can realize a high compression ratio beyond the limit of the compression ratio of the conventional gasoline engine, there is an advantage to maximize the fuel economy.

In such a direct injection gasoline engine, the fuel pressure is a very important factor, for which high performance high pressure fuel pump is required.

Conventional high pressure fuel pumps have a structure in which a pump shaft is rotated by the rotational force of the cam and the piston of the pump moves by the rotational force to form a pressure to supply gasoline fuel.

However, the conventional high pressure fuel pump has a disadvantage in that the price is expensive because it is a pump having a three-piston type.

In order to solve this problem, the present applicant has a single piston having a single pump piston in Korean Patent Application No. 10-2010-0031210 (filed April 6, 2010, hereinafter referred to as 'Patent Document 1') -high-pressure fuel pump for direct injection gasoline engine of the type (piston) has been disclosed and applied.

1 is a perspective view of a high-pressure fuel pump for direct injection type gasoline engine according to Patent Document 1, Figure 2 is a cross-sectional view of the high-pressure fuel pump shown in Figure 1, Figure 3 is an exploded perspective view of the damper portion shown in Figure 1, 4 is an operational state diagram showing an operation of supplying fuel through the first and second flow paths formed in the damper portion.

The high-pressure fuel pump for direct injection type gasoline engine according to Patent Document 1 is mounted on the engine camshaft, and as the pump shaft rotates by the cam's rotational force, the piston of the pump moves by the rotational force of the pump shaft to form a pressure, and the gasoline fuel is injected into the injector. Configured to supply.

In detail, the high-pressure fuel pump for direct injection type gasoline engine according to Patent Document 1 is composed of a piston (2a) and a return spring (2b), as shown in Figure 1 and 2 to exert the suction force of the fuel therein The suction member 2 is formed, the inlet side and the discharge side openings 3 and 4 are formed at both sides of the side, and the inlet port 1a and the outlet port 1b for injecting and discharging fuel are formed at the outer side, respectively. The body 1 having the coupling part 5 on which the damper part 6 is mounted, the damper part 6 which is coupled to the coupling part 5 of the body 1 and reduces the pulsation of the inhaled fuel, and the inlet opening. To the inlet side check valve (8) and the outlet side opening (4) coupled to the inlet opening (3) and coupled to the inlet opening (3), coupled to (3) and controlling the supply flow rate and discharge pressure. And a discharge side check valve 9 which is coupled.

3 and 4, the damper cover 6, the damper cover 11 is formed in a cylindrical shape having a lower opening to be coupled to the upper portion of the coupling portion 10 formed in the body 1, the coupling portion The lower guide 12 is formed in a circular ring shape to be inserted into the inside of the 10, the damper 13 is seated in the interior of the lower guide 12, and formed in a ring shape and positioned above the damper 13 An upper guide 14 is included.

A first protruding jaw 111 is formed on the inner side surface of the damper cover 11, and a groove 112 is formed in the upper portion of the first protruding jaw 111. The groove 112 is equipped with an O-ring 113 for maintaining airtightness.

After covering the damper cover 11 configured as described above in the engaging portion 10, the first protrusion (111) and the second protrusion (101) formed in the coupling portion 10 by pressing is coupled by interference fit.

The lower guide 12 has a plurality of first flow passages 121 formed at regular intervals in the circumferential direction, and a round bottom 122 on which the damper 13 is seated is formed on the inner circumferential surface of the lower guide 12.

A plurality of valleys 131 are formed on the outer surface of the damper 13, and an annular wing 132 is formed on the outer circumference. The wing 132 is inserted into the lower guide 12 and seated on the round jaw 122 of the lower guide 12.

The upper guide 14 is positioned above the damper 13 to press the wings 132 of the damper 13, and a plurality of second flow passages 141 are formed on the outer circumferential surface of the upper guide 14.

In the high-pressure fuel pump for a direct injection type gasoline engine according to Patent Document 1 configured as described above, pulsation of the sucked fuel occurs as the fuel is sucked only during the suction operation of the piston 2a. Reduces pulsation to ensure stable fuel delivery.

That is, the suction force is generated during the lowering operation of the piston (2a), the fuel is sucked through the inlet (1a), it is introduced into the damper portion 6 through the ascending passage 102 of the body (1).

Subsequently, the fuel flowing into the damper part 6 is discharged after the pulsation is reduced while passing through the valleys 121 of the damper 12 while moving through the first and second flow paths 111 and 131 as shown by the arrow shown in FIG. 4. It enters the spill valve 7 through the passage 102.

However, the high-pressure fuel pump for direct injection type gasoline engine according to Patent Document 1 has a problem that the fuel pulsation improvement performance in the high RPM region is remarkably deteriorated because the fuel flow in the damper portion 6 is not smooth.

Republic of Korea Patent Application No. 10-2010-0031210 (filed April 6, 2010)

The present invention is to solve the above problems, an object of the present invention is to provide a high-pressure fuel pump for direct injection gasoline engine to reduce the pulsation of the fuel sucked into the high-pressure fuel pump.

According to a feature of the present invention for achieving the above object, the present invention is a high-pressure fuel pump for a direct injection type gasoline engine having a body, a damper, a spill valve, an inlet check valve and a discharge check valve, The damper portion is formed in a cylindrical shape having a lower opening to be coupled to an upper portion of the coupling portion formed in the body, and a damper cover having a plurality of first moving grooves formed on an inner upper surface thereof, and a circular ring shape to be inserted into the coupling portion. And a lower guide having a first flow path formed at regular intervals, a damper seated in the lower guide, and a ring shape, and positioned at an upper portion of the damper and having a second flow path formed at regular intervals.

The first moving groove may be formed in the same number at a position corresponding to the first flow path formed in the lower guide, or may be formed in a greater number than the first flow path.

According to another feature of the present invention, the present invention provides a high-pressure fuel pump for a direct injection gasoline engine having a body, a damper part, a spill valve, an inlet check valve and a discharge check valve, wherein the damper part is a coupling part formed on the body. A damper cover having a cylindrical shape having a lower portion opened to be coupled to an upper portion, a lower guide formed in a circular ring shape to be inserted into the coupling portion, and having a first flow path formed at a predetermined interval, and seated inside the lower guide. And an upper guide formed in a damper and a ring shape and positioned at an upper portion of the damper and having a plurality of second moving grooves formed at predetermined intervals.

The second moving groove may be formed in the same number at the position corresponding to the first flow path formed in the lower guide, or may be formed in a greater number than the first flow path.

According to still another embodiment of the present invention, the present invention provides a high-pressure fuel pump for a direct injection gasoline engine having a body, a damper part, a spill valve, an inlet check valve, and a discharge check valve, wherein the damper part is formed on the body. The damper cover is formed in a cylindrical shape with a lower opening to be coupled to the upper portion of the coupling portion, and a plurality of first moving grooves are formed on the inner upper surface thereof. The lower guide is formed, the damper is seated in the interior of the lower guide and is formed in a ring shape and is located on the upper portion of the damper and includes a plurality of second guide grooves are formed at regular intervals.

The first moving groove may be formed in the same number at a position corresponding to the first flow path formed in the lower guide, or may be formed in a greater number than the first flow path.

The second moving groove may be formed in the same number at the position corresponding to the first flow path formed in the lower guide, or may be formed in a greater number than the first flow path.

As described above, the present invention increases the amount of fuel that moves through the first moving groove formed on the inner upper surface of the damper cover and / or the plurality of second moving grooves formed on the upper guide.

Accordingly, the present invention can improve the pulsation improving performance of the fuel by increasing the amount of fuel moving in the damper portion to smooth the flow of fuel.

In addition, the present invention can improve the pulsation improvement performance of the fuel by increasing the amount of fuel in the damper portion to increase the responsiveness of the damper when pulsation occurs.

In particular, the present invention can significantly improve the fuel pulsation improving performance in the high RPM region has the effect of increasing the fuel injection stability of the direct injection gasoline engine.

1 is a perspective view of a high-pressure fuel pump for a direct injection gasoline engine according to the prior art.
2 is a cross-sectional view of the high pressure fuel pump shown in FIG.
3 is an exploded perspective view of the damper unit shown in FIG. 1.
4 is an operational state diagram showing an operation of supplying fuel through first and second flow paths formed in the damper unit.
Figure 5 is a cross-sectional view of the damper portion applied to the high-pressure fuel pump for direct injection gasoline engine according to the first embodiment of the present invention.
FIG. 6 is a sectional perspective view of the damper cover shown in FIG. 5. FIG.
Figure 7 is a cross-sectional perspective view of the damper portion applied to the high-pressure fuel pump for direct injection gasoline engine according to the second embodiment of the present invention.
8 is a perspective view of the upper guide shown in FIG.
9 is a cross-sectional view of the damper portion applied to the high-pressure fuel pump for a direct injection gasoline engine according to a third embodiment of the present invention.
10 is a graph showing experimental results of measuring fuel pulsations in dampers according to the first to third embodiments and the prior art of the present invention.

Hereinafter, a high pressure fuel pump for a direct injection gasoline engine according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the present embodiment, the configuration of the high pressure fuel pump will be described using the configuration of the high pressure fuel pump illustrated in FIGS. 1 and 2.

And it should be noted that the high-pressure fuel pump described in this embodiment is a high-pressure fuel pump for a single-piston type direct injection gasoline engine having one pump piston that can be manufactured at low cost.

≪ Example 1 >

5 and 6 will be described in detail a high-pressure fuel pump for a direct injection gasoline engine according to a first embodiment of the present invention.

5 is a cross-sectional view of a damper part applied to the high-pressure fuel pump for a direct injection gasoline engine according to the first embodiment of the present invention, and FIG. 6 is a sectional perspective view of the damper cover shown in FIG. 5.

5 and 6, the damper portion 20 applied to the high-pressure fuel pump for a direct injection gasoline engine according to the first embodiment of the present invention is located on the upper portion of the coupling portion 10 formed in the body (1) The damper cover 21 is formed in a cylindrical shape having a lower opening to be coupled, and a plurality of first moving grooves 211 are formed on the inner upper surface thereof, and is formed in a circular ring shape so as to be inserted into the coupling part 10. The lower guide 22 is formed at intervals, the lower guide 22, the damper 23 seated in the lower guide 22 and the ring shape is formed in the upper portion of the damper 23 and the second flow path at regular intervals The upper guide 24 is formed.

That is, in the first embodiment of the present invention, a plurality of first moving grooves 211 are formed at regular intervals along the circumference of the upper surface of the damper cover 21 provided in the damper unit 20.

Here, the first moving groove 211 may be formed in the same number at the position corresponding to the first and second flow paths formed in the lower guide 22 and the upper guide 24, more than the first and second flow paths. It may be formed as.

The first moving groove 211 of the damper cover 21 allows a larger amount of fuel to move than the amount of fuel moving through the second passage 131 in Patent Document 1.

Accordingly, the present invention can improve the fuel pulsation improvement performance by increasing the amount of fuel moving through a plurality of first moving grooves formed on the inner upper surface of the damper cover provided in the damper portion to smooth the flow of fuel. .

<Example 2>

7 is a cross-sectional perspective view of a damper part applied to a high-pressure fuel pump for a direct injection gasoline engine according to a second embodiment of the present invention, and FIG. 8 is a perspective view of the upper guide shown in FIG. 7.

As shown in Figure 7 and 8, the damper portion 30 applied to the high-pressure fuel pump for direct injection gasoline engine according to the second embodiment of the present invention is located on the upper portion of the coupling portion 10 formed in the body (1) Damper cover 31 is formed in a cylindrical shape with a lower opening to be coupled, the lower guide 32 is formed in a circular ring shape to be inserted into the coupling portion 10 and the first flow path is formed at regular intervals, the lower The upper guide 34 is formed in the damper 33 and the ring shape seated on the inside of the guide 32 and positioned on the damper 33 and a plurality of second moving grooves 341 at regular intervals. do.

That is, in the second embodiment of the present invention, a plurality of second moving grooves 341 are formed at a predetermined interval on the upper portion of the upper guide 34 provided in the damper portion 30.

The second moving groove 341 of the upper guide 34 allows a larger amount of fuel to move than the amount of fuel moving through the second flow passage 131 described in Patent Document 1.

Accordingly, the present invention can improve the fuel pulsation improvement performance by increasing the amount of fuel moving through the plurality of second moving grooves formed in the upper portion of the upper guide provided in the damper to facilitate the flow of fuel.

<Example 3>

Next, the high-pressure fuel pump for the direct injection type gasoline engine according to the third embodiment of the present invention will be described in detail with reference to FIG. 9.

9 is a cross-sectional view of a damper portion applied to a high-pressure fuel pump for a direct injection gasoline engine according to a third embodiment of the present invention.

As shown in Figure 9, the damper portion 40 of the high-pressure fuel pump for direct injection type gasoline engine according to the third embodiment of the present invention has a lower portion to be coupled to the upper portion of the coupling portion 10 formed in the body (1) The damper cover 41 is formed in an open cylindrical shape and a plurality of first moving grooves 411 are formed on the inner upper surface thereof, and is formed in a circular ring shape so as to be inserted into the coupling part 10. The lower guide 42, the damper 43 is seated in the lower guide 42 and the ring is formed in the flow path is formed in the upper portion of the damper 43, the plurality of second moving grooves 441 at regular intervals The upper guide 44 is formed.

That is, in the third embodiment of the present invention, a plurality of first moving grooves 411 are formed on the inner upper surface of the damper cover 41 provided in the damper part 40 at predetermined intervals, and the upper part of the upper guide 44 is provided. The plurality of second moving grooves 441 are formed at regular intervals.

Here, the first and second moving grooves 411 and 441 may be formed in the same number at the position corresponding to the first flow path formed in the lower guide 42, or may be formed in a greater number than the first flow path.

In the first moving groove 411 of the damper cover 41 and the second moving groove 441 of the upper guide 44, a larger amount of fuel moves than the amount of fuel moving through the second flow path in Patent Document 1. Let's do it.

Accordingly, the present invention increases the amount of fuel moving through the first moving groove formed on the inner upper surface of the damper cover provided in the damper portion and the plurality of second moving grooves formed on the upper guide, thereby smoothing the flow of fuel. The fuel pulsation improvement performance of a damper part can be improved.

For example, FIG. 10 is a graph showing an experimental result of measuring fuel pulsation in the damper portion applied to the first to third embodiments and patent document 1 of the present invention.

In FIG. 10, the fuel pulsation in the damper portion applied to Patent Document 1 is A line, and the fuel pulsation in the damper portion 20 applied to the first embodiment of the present invention is B line, and according to the second embodiment of the present invention. The fuel pulsation in the applied damper section 30 is C line, and the fuel pulsation in the damper section 40 applied in the third embodiment of the present invention is D line.

In FIG. 10, the fuel pulsation of each damper part 6, 20, 30, 40 according to the RPM change of an engine is represented by the pressure difference (DELTA) P of a maximum pressure and a minimum pressure.

As shown in FIG. 10, in the damper part 6 applied to Patent Document 1, a pressure difference of about 10 bar occurs around 1500 RPM, but the damper part 20, 30, 40 applied to the first to third embodiments of the present invention. ), Only a pressure difference of about 6 bar occurred.

In the damper part 6 applied to Patent Literature 1, fuel pulsation rapidly increases to about 16 bar while exceeding 6000 RPM, but in the damper parts 20, 30, and 40 applied to the first to third embodiments of the present invention, Only 10 bar of fuel pulsation occurred.

In addition, it can be seen that in the damper parts 20, 30, and 40 applied to the first to third embodiments of the present invention, the pressure difference is reduced by about 1 to 2 bar as a whole than the damper part 6 applied to Patent Document 1.

As a result, the present invention can improve the fuel pulsation improvement performance by increasing the amount of fuel moving in the damper portion to increase the responsiveness of the damper when pulsation occurs.

Through the process as described above, the present invention can improve the pulsation improvement performance of the fuel by increasing the amount of fuel moving in the damper portion to facilitate the flow of fuel.

The scope of the present invention is not limited to the embodiments described above, but is defined by the claims, and various changes and modifications can be made by those skilled in the art within the scope of the claims. It is self evident.

1: body 2: suction member
3, 4: opening of inlet side and discharge side 7: spill valve
8: Inlet side and outlet side check valve 10: Coupling part
20, 30, 40: Damper part 21, 31, 41: Damper cover
211,411: first moving groove 22,32,42: lower guide
23,33,43: Dampers 24,34,44: Upper guide
341,441: second moving groove

Claims (7)

In the high-pressure fuel pump for a direct injection gasoline engine having a body (1), a damper portion (20), a spill valve (7), an inlet check valve (8) and a discharge check valve (9),
The damper unit 20
A damper cover 21 formed in a cylindrical shape having a lower opening to be coupled to an upper portion of the coupling portion 10 formed in the body 1 and having a plurality of first moving grooves 211 formed on an inner upper surface thereof;
A lower guide 22 formed in a circular ring shape to be inserted into the coupling part 10 and having a first flow path formed at a predetermined interval;
A damper 23 seated in the lower guide 22;
The high-pressure fuel pump for a direct injection gasoline engine, characterized in that it comprises a ring-shaped and located in the upper portion of the damper 23, the upper guide 24 is formed at a predetermined interval. The method of claim 1, wherein the first moving groove 211 is
The high-pressure fuel pump for a direct injection gasoline engine, characterized in that formed in the same number at the position corresponding to the first flow path formed in the lower guide 22 or more than the first flow path. In the high-pressure fuel pump for a direct injection gasoline engine having a body (1), a damper portion (30), a spill valve (7), an inlet check valve (8) and a discharge check valve (9),
The damper unit 30
A damper cover 31 formed in a cylindrical shape having a lower portion opened to be coupled to an upper portion of the coupling portion 10 formed in the body 1,
A lower guide 32 formed in a circular ring shape so as to be inserted into the coupling part 10 and having a first flow path formed at a predetermined interval;
A damper 33 seated in the lower guide 32;
High-pressure fuel pump for a gasoline engine, characterized in that it comprises a ring-shaped and located in the upper portion of the damper (33) and a plurality of second guide grooves (341) are formed at regular intervals. The method of claim 4, wherein the second moving groove 341 is
The high-pressure fuel pump for a direct injection gasoline engine, characterized in that formed in the same number at the position corresponding to the first flow path formed in the lower guide 32 or more than the first flow path. In the high-pressure fuel pump for a direct injection gasoline engine having a body (1), a damper portion (40), a spill valve (7), an inlet check valve (8) and a discharge check valve (9),
The damper portion 40 is
A damper cover 41 formed in a cylindrical shape having a lower portion opened to be coupled to an upper portion of the coupling portion 10 formed in the body 1 and having a plurality of first moving grooves 411 formed on an inner upper surface thereof;
A lower guide 42 formed in a circular ring shape to be inserted into the coupling part 10 and having a first flow path formed at a predetermined interval;
A damper 43 seated in the lower guide 42;
The high-pressure fuel pump for a direct injection gasoline engine, characterized in that it comprises a ring-shaped and located in the upper portion of the damper 43, the upper guide 44 is formed with a plurality of second moving grooves 441 at regular intervals. . The method of claim 5, wherein the first moving groove 411 is
High-pressure fuel pump for a direct injection gasoline engine, characterized in that formed in the same number at the position corresponding to the first flow path formed in the lower guide 42 or more than the first flow path. The method of claim 5 or 6, wherein the second moving groove 441 is
High-pressure fuel pump for a direct injection gasoline engine, characterized in that formed in the same number at the position corresponding to the first flow path formed in the lower guide 42 or more than the first flow path.

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