KR100394857B1 - Injector for direct injection type diesel engine - Google Patents

Abstract

The present invention relates to an injector for a direct injection diesel engine, the solenoid opening and closing means consisting of a ball member, a pilot needle, an electromagnet and a valve spring to open and close the fuel return passage in response to a signal input from the electronic control unit on the inner upper side of the body. An injector for a direct injection diesel engine, comprising: a split hole formed to spray fuel at the tip of the body; and a fuel formed to communicate with a fuel inflow passage at an upper end of the split hole; A pressure accumulating chamber, a fuel pressure adjusting chamber which is formed at a lower end of the fuel return passage to communicate with a fuel inlet passage, and which adjusts an inlet pressure of the fuel according to opening and closing of the fuel return passage; and an upper end portion is inserted into the fuel pressure adjusting chamber. The lower end is inserted into the fuel pressure storage chamber to open and close the tool hole. It characterized in that it comprises a injection valve which is operated up and down in accordance with the operation of the solenoid opening and closing means, and a valve spring for elastically supporting the injection valve to be able to. Therefore, the present invention does not need to configure the intake port of the cylinder head of a complicated shape since the vortex flow of the air which is inevitable when injected through a plurality of holes is not necessary, thereby increasing the amount of air, thereby increasing the output. . In addition, since there is no need to drill multiple holes, one spray spray pattern can be determined to simplify the processing process.

Description

Injector for direct injection diesel engines {INJECTOR FOR DIRECT INJECTION TYPE DIESEL ENGINE}

The present invention relates to an injector for a direct injection diesel engine, and more particularly, a direct injection diesel engine for achieving a fuel atomization pattern in the form of an atomized film so as to reduce the vortex flow of air during fuel injection to increase the utilization of air. It is related to the injector.

In general, a diesel engine of a vehicle generates compression heat of 500 to 550 ° C. when air is sucked into a cylinder, and at this time, a high-pressure injection of fuel through an injector is an ignition combustion engine. There are several types of combustion chambers of such diesel engines, which are classified into a direct injection chamber consisting of only one main combustion chamber, and a precombustion chamber, a vortex chamber, and an air chamber that require a secondary combustion chamber. In recent years, complicated indirect injection diesel engines have disappeared, and most new engines are using direct injection.

Fig. 1 shows a combustion chamber of a typical direct injection diesel engine, in which an injector 1 having a plurality of holes 1a is mounted in the cylinder head 2 so as to inject fuel. The piston 4 is coupled to the cylinder block 3 in a reciprocating manner up and down, and a curved groove 4a is formed in the upper surface of the piston 4. This direct type diesel engine has a vortex in which the fuel spray injected from the hole 1a of the injector 1 (approximately 5 to 6 in the case of a small size) is formed in the curved groove 4a during the compression stroke of the piston 4. By mixing with compressed air by movement, it increases the air utilization rate and promotes combustion.

In the fuel injector of such a direct injection diesel engine, the existing mechanical type is replaced by electronic rotary, TICS, EUI, and common rail system, and in a small diesel engine, in the control of various injection parameters, The common rail system with a large degree of freedom is in the mainstream process.

As shown in FIG. 2, the conventional common rail fuel injector includes a fuel tank 10, a fuel supply pump 20, a high pressure pump 30, a fuel rail 40, A plurality of injectors 50 are connected in series by the fuel supply pipe 60. In addition, the injector 50 and the high pressure pump 30 are also connected to the fuel tank 10 and the fuel return pipe 70. The rail pressure sensor 42 is mounted on the fuel rail 40, and the fuel pressure regulating valves 32 and 34 are mounted on the high pressure pump 30. The sensor 42, the valves 32, 34 and the injectors 50 are electrically connected to input and output signals of the electronic control unit (ECU) 80.

Referring to the operation of the conventional fuel injection device, the fuel sent from the fuel tank 10 to the high pressure pump 30 through the fuel supply pump 20 is pressurized, and then accumulates at high pressure in the fuel rail 40. . The fuel pressure in the fuel rail 40, that is, the injection pressure, is controlled to an optimum value in accordance with the engine operating conditions. The electronic control unit 80 measures the fuel pressure in the rail 40 through the rail pressure sensor 42, and operates the fuel pressure regulating valves 32 and 34 mounted on the high pressure pump 30 to operate conditions. Therefore, feedback is controlled to maintain the mapped value. The high pressure fuel in the fuel rail 40 is injected into the combustion chamber during the time that the solenoid valve (not shown) of the injector 50 is operated.

Here, the internal structure of the conventional injector 50, as shown in Figure 3, the inside of the body 51 can adjust the intake, discharge of the fuel supplied through the fuel inlet passage 51a along the longitudinal direction The adjustment chamber 51b is provided. The piston 52 and the needle 53 are connected to the lower portion of the adjustment chamber 51b with the pressure pins 54 therebetween so as to move up and down. A nozzle spring 55a is interposed around the lower end of the piston 52 to apply tension. The needle 53 is inserted to open and close the hole 51d at the lower end of the body 51 through the fuel accumulation chamber 51c communicating with the fuel inflow passage 51a.

On the other hand, a fuel return passage 51e communicates with an upper end of the adjustment chamber 51b, and components of the solenoid opening and closing means are disposed in the space 51f above the fuel return passage 51e. That is, the ball member 56 and the pilot needle (Pilot Needle) 57 is integrally provided to open and close the passage (51e), the valve spring (Valve Spring) 55b around the upper end of the pilot needle (57) ) Is interposed so that tension can be applied. In addition, a return spring 55c is also interposed around the body of the pilot needle 57. The electromagnet 58 is provided around the pilot needle 57 to be powered by the power line 59. Of course, the fuel supply pipe 60 is connected to the fuel inflow passage 51a, and the fuel return pipe 70 is connected to the fuel return passage 51f.

The operation relationship of the conventional injector 50 provided as above will be described with reference to FIGS. 2 and 3. Normally, when the high-pressure fuel supplied from the fuel rail 40 is filled in the adjustment chamber 51b and presses the piston 52, this pressing force is applied to the needle 53 by the fuel pressure filled in the accumulation chamber 51c. Since the needle 53 becomes larger than the force to lift the needle 53, the needle block 53d is blocked and the fuel is not injected. On the other hand, when the drive signal generated by the electronic control unit (ECU) 80 is applied to the electromagnet 58 along the power supply line 59, the ball member 56 and the pilot needle 57 are held by the electromagnetic force. It is pulled up and moved up. At this time, the fuel filled in the adjustment chamber 51b exits to the fuel return pipe 70 through the fuel return passage 51e. Therefore, the pressure of the fuel acting on the upper ends of the needle 53 and the piston 52 is removed, and the needle 53 is lifted by the inflow pressure of the fuel that is charged in the accumulation chamber 51c, through the hole hole 51d. Fuel is injected

However, if insufficient vortex flow occurs during fuel injection, air and fuel are not mixed smoothly, and thus the air utilization rate is lowered, and the rich area is increased, so that a lot of soot is emitted. . Therefore, in order to ensure sufficient vortex flow, the intake port must be helically bent or a tangent port bent toward the wall. However, the greater the curvature of these curved ports, the greater the vortex strength of the intake air flow, but on the contrary, a significant amount of kinetic energy of the intake air is converted into vortex flow and an increase in flow resistance due to an increase in port length also results in an increase in flow resistance. The amount of air entering will be reduced. This represents a limit of the output. For example, for gasoline engines, the output of a Lean Burn engine, which requires vortex flow for lean combustion, is usually less than that of an engine.

Therefore, there is a difficulty in acquiring the opposite parameters of the air volume and the vortex level to enable the target output. If the amount of vortex required by the combustion system is smaller, more air volume can be secured, so that the output can be increased at the same soot limit. One way to reduce the amount of vortex is to increase the pressure of fuel injection. This has been and continues to be done. This makes it possible to increase the number of holes while reducing the area of the holes, which in turn promotes mixing of fuel and air in an atomized spray pattern.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to reduce the vortex flow of air during fuel injection, thereby ensuring sufficient air volume, thereby promoting the mixing of fuel and air, and It is to provide an injector for a direct injection diesel engine that also increases power.

1 is a cross-sectional view showing a combustion chamber of a general direct injection diesel engine.

2 is a view schematically showing the configuration of a fuel injection device for a direct injection diesel engine according to a conventional embodiment.

3 is a cross-sectional view showing the internal configuration of the injector shown in FIG.

4 is a cross-sectional view showing the internal configuration of an injector for a direct injection diesel engine according to the present embodiment.

※ Explanation of codes for main parts of drawing

500: injector 510: body

511: fuel inlet passage 512: ball hole

513: fuel pressure storage chamber 514: fuel pressure adjustment chamber

515: fuel return passage 520: injection valve

522: lower part 524: upper part

530, 570: valve spring 540: adjustment ring

550: ball member 560: pilot needle

580: electromagnet 590: power line

600: fuel supply pipe 700: fuel return pipe

800: electronic control unit (ECU)

The injector for a direct injection diesel engine according to the present invention for achieving the above object, the ball member, pilot needle, electromagnet and valve to receive the signal input from the electronic control unit on the inner upper side of the body to open and close the fuel return passage An injector for a direct injection type diesel engine having a solenoid opening and closing means formed of a spring, comprising: an air outlet formed to spray fuel at a tip of the body, and a fuel inlet pressure formed at an upper end of the air outlet to communicate with a fuel inflow passage; A fuel pressure accumulation chamber capable of accumulating gas, a fuel pressure adjusting chamber configured to communicate with a fuel inflow passage at a lower end of the fuel return passage, and to adjust the inflow pressure of the fuel according to opening and closing of the fuel return passage; An upper end is inserted into the adjustment chamber, and a lower end is inserted into the fuel pressure storage chamber. And the injection valve which mouth is operational minutes up and down according to the operation of the solenoid opening and closing means so as to open and close the tool, characterized in that it comprises a valve spring for elastically supporting the injection valve.

It is preferable that an adjustment ring is interposed around the injection valve so as to limit the working distance of the injection valve.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

4 is a cross-sectional view showing an internal configuration of an injector for a direct injection diesel engine according to the present embodiment.

In the figure, reference numeral 500 denotes an injector of the present embodiment, and is formed through the hole 512, which is formed in a conical shape that can spray fuel to the tip of the body 510, in an open state. A fuel pressure storage chamber 513 is formed at an upper end of the hole 512 so as to communicate with the fuel inflow passage 511. Here, the fuel pressure accumulation chamber 513 is connected to the fuel inflow passage 511 through the fuel supply pipe 600. The inflow pressure can be accumulated to act on the tip 522 of the injection valve 520 described later.

A fuel pressure adjusting chamber 514 is provided at an inner central side of the body 510, that is, at an intermediate position where the fuel inflow passage 511 and the fuel return passage 515 communicate with each other, and here, the opening and closing action of the fuel return passage 515 is provided. This is where the inlet pressure of the fuel is adjusted.

Reference numeral 520 denotes an injection valve, in which an upper end 524 of the injection valve 520 is inserted into the fuel pressure adjusting chamber 514, while a lower end 522 of the valve 520 passes through the fuel pressure storing chamber 513. It is coupled to open and close the ball hole 512. The lower end portion 522 of the injection valve 520 has a shape in which the cone shape is inverted to correspond to the shape of the hole 512.

In addition, inside the fuel pressure adjusting chamber 514, a valve spring 530 having a tension enough to close the hole 512 is interposed around the body of the injection valve 520.

Furthermore, if an adjustment ring 540 is further interposed around the body of the injection valve 520, it is highly desirable to limit the working distance of the injection valve 520 in the pressure adjustment chamber 514. That is, the spray amount can be adjusted by changing the length of the adjustment ring 540.

The upper space portion 516 of the fuel return passage 515 is provided with solenoid opening and closing means. Looking at the configuration of the solenoid opening and closing means, the ball member 550 and the pilot needle (Pilot Needle) 560 is provided integrally to open and close the fuel return passage (515). Around the top of the pilot needle 560 is interposed so that another valve spring 570 can apply tension, i.e. tension to close the fuel return passage 515 below with the ball member 550. The electromagnet 580 is provided around the pilot needle 560 to receive an open / close signal from the electronic control unit (ECU) 800 through the power line 590. Of course, the fuel return pipe 700 that leads to the fuel tank (not shown) is connected to the outside of the fuel return passage 515.

It looks at the operating relationship of the injector 500 for a direct injection diesel engine according to this embodiment provided as described above. The present embodiment has a structure in which a fuel spray pattern is injected from an infinite number of holes 512 by using one hole 512 limited to the limit of the number of holes. In the present embodiment, the injection valve 520 is used instead of the conventional needle (53 in FIG. 3), and in the injection method, the injection valve 520 must be pushed out downward as opposed to the injection of fuel when the needle 53 is raised. Take the form of fuel injection.

The high pressure fuel supplied from the fuel rail (not shown) into the injector 500 through the fuel supply pipe 600 is filled in the fuel pressure adjusting chamber 514 and the fuel pressure storing chamber 512 via the fuel inflow passage 511. . In general, the force between the fuel pressure applied to the fuel pressure adjusting chamber 514 and the tension of the valve spring 530 is stronger than the force due to the fuel pressure applied to the fuel pressure storing chamber 513, so that The lower portion 513 is pulled up to block the hole 512. Therefore no fuel is injected.

On the other hand, when the driving signal generated by the electronic control unit (ECU) 800 is input to the electromagnet 580, that is, the solenoid, by the power line 590, the ball member 550 and the pilot needle (Pilot) The needle 560 is pulled up to open the fuel return passage 515. At this time, the high-pressure fuel filled in the fuel pressure adjusting chamber 514 is discharged to the fuel return pipe 700 through the fuel return passage 515. After that, when the pressure of the fuel pressure adjusting chamber 514 drops and the pressure of the fuel pressure storing chamber 513 becomes stronger than the force of the valve spring 530, the pressure of the fuel pressure adjusting chamber 514 is applied to the lower end portion 522 of the injection valve 520, thereby actuating the valve 520. ) Is pushed out of the tool hole 512. At this time, the valve 520 is opened with a gap equal to the adjustment interval of the adjustment ring 540 serving as a stopper of the injection valve 520 to inject fuel.

The working principle of this embodiment is similar to the conventional one, but the spray pattern is completely different. And there are no separate separation holes. However, fuel is injected into a gap (called as a hole 512 in this embodiment) between the lower end of the injector body 510 and the lower end 522 of the injection valve 520. Therefore, the spray pattern is sprayed in the form of a film, which looks like an upside down of one narrow cone, that is, a funnel, unlike conventional spraying by the number of holes. Of course, the thickness of this spray film is determined by the length of the adjustment ring 540.

According to the present invention described above, the same effect as the infinite number of fuel spray is injected, so the vortex flow which was inevitably needed to use the air between each fuel spray when injected through a plurality of holes as in the prior art is almost necessary Disappear. Therefore, it is not necessary to configure the intake port of the cylinder head of a complicated shape, thereby causing an increase in the amount of air, further increasing the output. In addition, since there is no need to drill multiple holes, one spray spray pattern can be determined to simplify the processing process.

Claims (2)

In the injector for the direct injection diesel engine having a solenoid opening and closing means consisting of a ball member, a pilot needle, an electromagnet and a valve spring to open and close the fuel return passage in response to a signal input from the electronic control unit on the inner upper side of the body, A ball hole formed to spray fuel at the tip of the body; A fuel pressure accumulation chamber which is formed to communicate with a fuel inflow passage at an upper end of the split hole and can accumulate fuel inflow pressure; A fuel pressure adjusting chamber formed at a lower end of the fuel return passage so as to communicate with the fuel inlet passage and adjusting the inlet pressure of the fuel according to opening and closing of the fuel return passage; An injection valve which is inserted into the fuel pressure adjusting chamber and is operated up and down in accordance with the operation of the solenoid opening and closing means so that the lower portion is inserted into the fuel pressure storing chamber so as to open and close the tool hole; Injector for a direct injection diesel engine comprising a valve spring for elastically supporting the injection valve. The method of claim 1, Injector for the direct injection type diesel engine, characterized in that the circumference of the injection valve is provided with an adjustment ring to limit the operating distance of the injection valve.