KR20020036232A - Injector for gasoline direct injection - Google Patents

Abstract

PURPOSE: An injector is provided to adjust fuel swirl amount appropriately to a driving condition of engine. CONSTITUTION: A nozzle tip(50) has a plurality of protrusion to pass fuel to a groove(51). A needle(30) has a plurality of connection hole(33) inside of a through hole(32). A needle guide(40) has a swirler(41) to connect with the nozzle tip(50). A knob(60) rotates the needle guide(40) in a certain angle to control swirl amount of injected fuel.

Description

Injector for gasoline direct injection

The present invention relates to a gasoline direct injection injector, and more particularly, to a gasoline direct injection injector to adjust the swirl amount of the fuel injected into the combustion chamber from the injector mounted on the gasoline direct injection engine. .

In general, fuel injection of an automobile gasoline engine employs an electronically controlled system, and a type of injection into an intake manifold is mainly used. The basic principle of the fuel injection is to always apply a constant pressure to the fuel system, open the nozzle of the injector to eject fuel into the intake manifold.

The control of the electronic fuel injection is to realize the engine's output performance, fuel economy and pollution gas reduction under various driving conditions.For this purpose, the engine's coolant temperature, intake air temperature, intake manifold pressure and atmospheric pressure After detecting the vehicle speed, the throttle opening amount, the crank angle signal, and the like using various sensors, the electronic control unit (ECU) controls the air conditioner relay, fuel pump relay, injector, ignition coil, and ISC valve.

The control by the electronic control unit (ECU) can be divided into injection timing control and injection amount control. First, the injection timing control uses the ignition signal of the ignition coil, and the injection amount control creates the basic injection time by the ignition signal and the intake air amount signal of the ignition coil, and simultaneously corrects the injection time by the detection signal from each sensor. Final injection time is set to operate.

On the other hand, the direct injection (Direct Injection) method of directly injecting fuel into the combustion chamber is mainly used in large-sized diesel engines with slow rotation, but is now also widely used in high-speed diesel engines.

In addition, in recent years, the direct injection method has been adopted in gasoline engines to improve thermal efficiency.

The injector used in the conventional gasoline direct injection type engine will be described with reference to FIG. 7 as follows.

As shown in FIG. 7, the needle 12 is integrally formed with the disc 13 in which the plurality of through holes 13a are formed in the housing 11 of the injector 10.

The lower end of the needle 12 is configured to open and close the injection hole 14a formed in the nozzle tip 14, so that the disk 13 formed in the middle of the needle 12 is moved by the armature 16 It is to open and close the injection port (14a). That is, when a current is applied to the coil 15, the armature 16 pulls the disc 13, so that the needle 12 is lifted up to open the injection hole 14a.

That is, the fuel passes through the inlet port 17 formed in the upper part of the housing 11 and is maintained at a high pressure while being filtered by the filter 18, and the current is supplied to the coil 15 by the control of the electronic control unit ECU. When the needle 12 is moved upward, the injection hole 13a is opened, and the high pressure fuel is injected into the combustion chamber.

However, while the engine is operated under a variety of conditions from low speed to high speed, and low load to high load, the swirl amount of fuel injected from the above-mentioned injector is constant, so that fuel injection is not made according to the engine operating conditions, thereby deteriorating fuel economy and engine output There was a problem of this degradation.

Therefore, the present invention has been made in order to improve the above problems, more specifically, the gasoline direct injection type to adjust the swirl amount of the fuel injected into the combustion chamber from the injector mounted on the gasoline direct injection type engine according to the operating conditions of the engine The purpose is to provide an injector.

The present invention as a means for achieving the above object,

In a direct injection injector of an engine in which a needle formed inside the housing is moved in accordance with the presence or absence of current applied to the coil, and the lower end of the needle opens and closes the nozzle tip to directly inject fuel supplied from the fuel pump into the combustion chamber.

A plurality of protruding jaws are formed regularly so that fuel can pass through the groove in the inner diameter, and one side of the protruding jaw is formed in a vertical plane and the other side is formed in an inclined plane and press-formed at the lower end of the housing; ;

A needle having a plurality of through holes formed in a middle portion with a long circular rod for opening and closing the injection hole of the nozzle tip, and having a plurality of coupling holes formed at the through hole side;

A needle guide having a lower portion formed by a cylindrical rod to accommodate the needle, and a plurality of connecting legs inserted into the coupling hole of the needle, and a swirler formed at the lower portion at the lower portion thereof;

A knob coupled to each end of the coupling leg to rotate the needle guide at an angle; It is characterized in that the swirl amount of the fuel injected and formed is configured to be adjustable,

The swirler is provided with grooves and protrusions on the outer circumference of the truncated barrel formed at the lower end of the needle guide, and both sides of the protrusions are parallel to the vertical and inclined surfaces of the nozzle tip when mating with the nozzle tip. Characterized in that the vertical and inclined surfaces are formed,

The knob is characterized in that it is driven by a step motor operated by the control of the electronic control unit (ECU).

1 is a cross-sectional view of an injector constructed in accordance with the present invention.

2 is a perspective view of an essential part constituted by the present invention;

3 is a cross-sectional view taken along the line A-A of FIG.

4 is a cross-sectional view taken along a line A-A in FIG. 1 to swirl the fuel;

5 and 6 are views showing a state in which the nozzle tip is open and closed, respectively.

7 is a cross-sectional view of a conventional injector.

※ Explanation of code for main part of drawing

20: injector 21: housing

23: coil 24: amateur

30: needle 31: disc

32: through hole 33: coupling hole

40: needle guide 41: swirler

50: nozzle tip 60: knob

When explaining the embodiment according to the configuration and operation of the present invention in detail with the drawings as follows.

1 is a cross-sectional view of an injector constructed in accordance with the present invention, FIG. 2 is a perspective view of an essential part constructed in accordance with the present invention, FIG. 3 is a cross-sectional view taken along line AA of FIG. 1, and FIG. It is a state line which swirl-injects fuel as AA sectional drawing, and FIG. 5 and FIG. 6 are the figure which shows the state which the nozzle tip opened and the state closed, respectively.

Reference numeral 20 denoted in the drawing indicates an injector constructed by the present invention, and reference numeral 30 denotes a needle.

As described above, the injector 20 is provided with an armature 24 that operates when a current is supplied to the coil 23 in the accommodation space 22 inside the housing 21.

The needle 30, which is operated by the operation of the armature 24 and opens and closes the injection port 55 of the injector 20, has a long circular rod having a plurality of through holes 32 in the middle thereof. ) Is formed, and a plurality of coupling holes 33 into which the connecting legs 45 of the needle guide 40 to be rearranged are inserted into the through holes 32.

And the needle guide 40 for guiding the shanghaidong of the needle 30 is formed of a cylindrical rod to accommodate the lower portion of the needle 30, the upper portion is a coupling hole formed in the disc 30 of the needle (30) A plurality of connecting legs 46 fitted in the 33 are formed long and thin. In addition, a swirler 41 is formed at the lower end of the needle guide 40 to be joined to the nozzle tip 50. The swirler 41 has a plurality of grooves 42 and protrusions 43 formed on a cone that is normally narrow. do. In particular, one side constituting the groove 42 and the protrusion 43 is formed as a vertical surface 44 and the other side is formed as an inclined surface 45.

And the nozzle tip 50 is press-fitted to the lower end of the injector 20, the lower portion of the nozzle tip 50 is formed with an injection hole 55 for injection of fuel, the inner periphery to cause the swirl as the fuel passes through Grooves 51 and protrusions 52 are formed. Both surfaces forming the groove 51 and the protrusion 52 are formed in parallel with the vertical surface 44 and the inclined surface 45 of the swirler 41, so that fuel is injected into the sprayer 55 when mated with the swirler 41. Injection passage 56 is moved up to) is made.

In addition, a knob 60 for rotating the needle guide 40 is formed at the top of the injector 20. The knob 60 is preferably driven by the step motor 61 operated by the electronic control unit ECU in accordance with the rotational conditions of the engine.

In addition, an inlet 25 through which fuel flows is formed at one upper side of the housing 21, and a filter 28 that filters foreign substances from the fuel is formed at the rear of the inlet 25.

In the figure, reference numeral 29 is a connector connected to supply a current to the coil.

The needle 30, the needle guide 40, the nozzle tip 50, and the knob 60, which are configured as described above, are assembled as follows.

First, the nozzle tip 50 is press-fitted into the lower end of the injector 20, the housing 21, and the swirler 41 formed at the lower end of the receiving space 22 formed in the housing 21 is the nozzle tip ( The needle guide 40 is accommodated so as to be fitted to the 50, and the needle guide 40 has a lower portion of the needle 30 so that the disc 31 of the needle 30 comes into close contact with the seat 27 of the housing 21. Are accepted. At this time, the connecting leg 46 formed on the needle guide 40 is fitted into the coupling hole 33 formed in the disc 31, respectively, and the upper end of the knob 60 rotates by the step motor 61, respectively. Is coupled to.

Referring to the operation of the gasoline direct injection injector configured as described above is as follows.

The high pressure fuel pumped by the fuel pump and introduced into the inlet 25 is injected into the housing 21 after the foreign matter is removed by the filter 28 and then injected into the housing 21 by the repeated operation of the needle 30. It is injected into the combustion chamber through.

In low-speed, low-load regions of gasoline direct injection engines, fuel is injected at the end of the compression cycle so that a mixer is formed only around the spark plug and no fuel is present away from the spark plug so that it can run in lean conditions throughout the combustion chamber. This is called stratified combustion. In this state, it is possible to reduce fuel consumption due to lean combustion and to ensure combustion stability due to an appropriate mixer around the spark plug. On the other hand, at high speeds or high loads, fuel is injected during intake stroke and mixed with air during compression stroke to combust in a homogeneous mixer, which is called homogeneous combustion. In this state, the engine needs maximum power or is used for high speed driving. Since gasoline direct injection engines use such different fuel injection methods together, injection characteristics appropriate to each area are required. That is, in the above-mentioned stratified combustion region, high swirl strength with short spray arrival and good mixing is required to obtain a good mixer in a narrow combustion chamber volume for a short time from injection to ignition.

Therefore, when the engine is running at low speed or under low load, and operates in the stratified combustion region, the ECU controls the step motor 61 to rotate the knob 60 to one side. When the knob 60 rotates to one side, the needle 30 and the needle guide 40 connected through the connecting leg 46 also rotate accordingly. At this time, the swirler 41 is positioned as shown in FIG. 4 so that the injection passage 56 formed in a straight line is inclined.

On the other hand, in the homogeneous combustion region at high speed or high load, the combustion chamber volume in the intake stroke is large and there is sufficient time for mixing, and low swirl strength is advantageous because many fuels must be injected.

Therefore, the injector 20 according to the present invention has the position of the swirler 41 as shown in FIG. 3 when the engine is running at low speed or under low load, and in the electronic control unit ECU, the coil ( The armature 24 is operated by repeatedly applying a current to 23). Then, the disk 31 of the needle 30 is moved by the operation of the amateur 24, the high pressure fuel is injected straight into the combustion chamber while the injection port 55 of the nozzle tip 50 is opened and closed repeatedly. At this time, the injection passage 56 formed between the swirler 41 and the nozzle tip 50 is formed in a straight line.

Therefore, the high-pressure fuel passing through the inclined injection passage 56 causes swirl, and the fuel injected from the injection port 55 into the combustion chamber is strongly injected in the state of causing the swirl.

As described above, the present invention forms a nozzle tip and a swirler for generating a swirl in the injector housing, and the swirler is adjusted according to the operating conditions of the engine by the electronic controller so that the amount of fuel injected into the combustion chamber is automatically generated. By adjusting with the fuel economy is improved and the engine output is a big advantage.

Claims (3)

The needle 30 formed inside the housing 21 is moved in accordance with the presence or absence of current applied to the coil, and the lower end of the needle 30 opens and closes the nozzle tip 50 to directly supply fuel supplied from the fuel pump to the combustion chamber. In the direct injection injector 20 of the engine to be injected, A plurality of protrusions 52 are regularly formed to allow fuel to pass through the grooves 51 in the inner diameter, one side of which is formed as a vertical surface 53 and the other side is an inclined surface 54. A nozzle tip (50) formed by press-fitting the lower end of the housing (21); A disk 31 having a plurality of through holes 32 is formed in the middle part of a long circular rod that opens and closes the injection hole 55 of the nozzle tip 50. A needle 30 in which the coupling hole 33 is formed; In order to accommodate the needle 30, the lower part is formed of a cylindrical rod, and the upper part is formed with a plurality of connecting legs 46 fitted in the coupling hole 53 of the needle 30, the lower end of the nozzle tip A needle guide 40 formed with a swirler 41 to be joined to 50; A knob 60 coupled to each end of the coupling leg 45 to rotate the needle guide 40 by a predetermined angle; The gasoline direct injection injector, characterized in that the swirl amount of the fuel injected is configured to be adjustable. The method of claim 1, The swirler 51 is formed with a groove 42 and a protrusion 43 on the outer circumference of the truncated conical barrel formed at the lower end of the needle guide 40, both sides of the protrusion 43 is the nozzle tip described above. Gasoline direct injection injector, characterized in that the vertical surface 44 and the inclined surface 45 is formed to be parallel to the vertical surface 53 and the inclined surface 54 of the nozzle tip 50 at the time of mating. The method of claim 1, The knob (60) is a gasoline direct injection injector, characterized in that driven by a step motor (61) operated by the control of the electronic control unit (ECU).