CN211422812U - Fuel injector, fuel injection system and internal combustion engine - Google Patents

Abstract

The utility model relates to a fuel injector, the fuel injector includes control piston (18) that can be guided in longitudinal motion ground in piston chamber (10), control piston (18) with a terminal surface boundary limit in one side that deviates from control piston (18) via control room (11) that draining hole and a cavity (2) are connected and with another tip with the nozzle needle (19) effect of fuel injector is connected, makes nozzle needle (19) can implement to open the motion or close the motion, wherein the fuel injector is inside to be constructed with return oil passageway (13), return oil passageway (13) are followed cavity (2) are drawn forth and via oil drain hole (14) with the oil return pipe of internal-combustion engine connects, oil drain hole (14) to inside extending of fuel injector until let in piston chamber (10). The utility model discloses still relate to one kind include the fuel injection system of sprayer and one kind include fuel injection system's internal-combustion engine.

Description

Fuel injector, fuel injection system and internal combustion engine

Technical Field

The present invention relates to a fuel injector, and more particularly to an electromagnetic fuel injector which can be used in a common rail injection system of an internal combustion engine (e.g., a diesel engine).

The utility model relates to a corresponding fuel injection system and corresponding internal-combustion engine.

Background

Electromagnetic fuel injectors are used to inject high pressure fuel into the combustion chambers of internal combustion engines and are widely used in common rail injection systems due to their precise control and high speed response to fuel injection. The actuating mechanism enables the nozzle needle to perform reciprocating linear motion so as to open and close the fuel injector.

The oil injector mainly comprises an oil nozzle, a hydraulic servo system, an electromagnetic valve and the like. The high-pressure fuel oil flows to the fuel spray nozzle through the high-pressure oil duct and flows to the control cavity through the throttling small hole, and the control cavity is connected with a low-pressure loop of the fuel oil through an oil drainage hole controlled by an electromagnetic valve. When the oil drain hole is closed, the hydraulic pressure acting on the control piston is larger than the force acting on the nozzle needle, so that the valve needle closes the injection hole of the nozzle. After the solenoid valve of the injector is triggered, the drain hole opens, so that the pressure in the control chamber drops and the hydraulic pressure acting on the control piston drops. As soon as the hydraulic pressure is lower than the force on the nozzle needle, the injection hole of the nozzle is opened and fuel is injected into the combustion chamber through the injection hole. During the operation of the fuel injector, high-pressure fuel can leak to the low-pressure loop from the clearance between the control piston and the nozzle matching part, and meanwhile, the fuel from the oil drainage hole can return to the low-pressure loop.

The injector body is one of the key components of the overall injector, which is subjected to high pressure fuel above 1600 bar.

In the prior art, as shown in fig. 1, an oil return port 7 is connected with an external oil return pipeline, an oil return channel 6 inside an oil injector is directly communicated with the oil return port 7, and the oil return channel 6 and a longitudinal oil return channel 4 are upwards connected with a cavity 2 of a hydraulic servo system so as to collect and guide oil return generated by high-pressure leakage. The return oil after the control chamber drain hole is opened is also collected in the return oil hole 7 through the return oil passage 6, and flows into the low-pressure circuit. In order to introduce the return oil generated by the high-pressure leakage into the longitudinal return oil channel 4, a transverse bore 3 leads out of the piston chamber, which opens up into the cavity 2 of the hydraulic servo system via the longitudinal return oil channel 4. The return opening 7 is connected to an external fuel system return line, so that both the leakage oil from the injector and the return oil from the control chamber and the piston chamber are drained via the return opening 7 and flow back into the tank.

Here, the transverse bore 3 opens out into the outer wall of the injector body, as required by the machining process, and therefore a sealing ball 5 is used to seal this bore. This increases on the one hand the sealing arrangement and the sealing procedure, which makes the manufacture of the fuel injector complicated and laborious and increases costs, and on the other hand increases the potential leakage points and thus the leakage risk.

SUMMERY OF THE UTILITY MODEL

The object of the present invention is therefore to propose an improved fuel injector, in particular an electromagnetic fuel injector for use in common rail injection systems, in order to avoid the above-mentioned complications and risks of leakage of the prior art.

In order to achieve this object, according to the invention, a fuel injector for injecting fuel into a combustion chamber of an internal combustion engine is proposed, comprising a control piston which is guided in a piston chamber so as to be longitudinally movable, the control piston delimits with one end face a control chamber, which is connected to a cavity on the side facing away from the control piston via a drain opening, the control piston is operatively connected at the other end to a nozzle needle of the fuel injector in such a way that the nozzle needle can perform an opening movement in the longitudinal direction of the fuel injector for releasing injection openings or a closing movement for closing injection openings, an oil return channel is formed in the fuel injector, is led out of the cavity and is connected with an oil return pipeline of the internal combustion engine through an oil drain port, and the oil drain port extends into the fuel injector until the oil drain port leads into the piston chamber.

Through direct extension of oil drain port let in the piston chamber, compare with prior art, the utility model discloses save from the piston chamber draw forth, additional transverse hole, saved the sealing device who is used for sealing this transverse hole simultaneously, simplified manufacturing on the one hand, the cost is reduced, and on the other hand has reduced latent leakage position, has improved the safety in utilization.

Therefore, through the utility model discloses, the processing of transverse hole has been reduced for processing technology is more simple, thereby the reduction of reduction the processing cost. In addition, a sealing component for sealing the transverse hole and an assembly process are omitted, and the assembly efficiency of the whole fuel injector is improved. Furthermore, the absence of the transverse bore eliminates the potential risk of high pressure fuel leaking from the transverse bore. The reliability of the whole oil injection system is improved.

Advantageously, the oil return channel opens at the boundary of the control piston and the nozzle needle on the side facing away from the cavity. This allows leakage, which occurs at the control piston and the nozzle needle as a result of the high pressure of the fuel, to be conducted back into the tank.

Advantageously, the oil return passage extends in a longitudinal direction of the injector. The return channel can thus be used to conduct fuel to be returned to the tank from different points in the longitudinal direction of the injector.

Advantageously, the oil drain port extends in a lateral direction of the fuel injector. The transversely extending oil drain port is convenient to machine.

Advantageously, an actuator is arranged in the cavity for actuating the longitudinal movement of the control piston.

Advantageously, the actuator is designed as an electromagnetic actuator, the oil drain opening being closable or releasable by movement of an armature of the electromagnetic actuator. The electromagnetic actuator is low cost and reliable in use.

Advantageously, the control chamber is connected to the filling control opening, so that the control chamber can be alternately supplied with high-pressure fuel or low-pressure fuel. The control piston and thus the direction of movement of the nozzle needle can thus be controlled by a change in the fuel pressure acting on the control chamber.

Advantageously, the injector is configured as a common rail injector. In this case, the high fuel pressure is the fuel pressure in the high pressure common rail.

According to the utility model discloses, still provide a fuel injection system, fuel injection system includes aforementioned sprayer.

Furthermore, an internal combustion engine is proposed, which comprises the aforementioned fuel injection system.

Drawings

The invention is explained in more detail below with reference to the drawings. The figures show:

figure 1 is a partial cross-sectional view of a fuel injector according to the prior art,

figure 2 is a partial cross-sectional view of a fuel injector according to the present invention.

Detailed Description

In fig. 2 a fuel injector according to the invention is shown partially. The injector is configured as a common rail injector.

The fuel injector comprises an actuator 16 in the form of an electromagnetic actuator, wherein a ball is formed below the electromagnetic armature, which ball can close or release a drain opening located therebelow. The drain opening is connected to the control chamber 11, and the upper end face of the control piston 18 delimits the control chamber 11. A control piston 18 (seen in the direction shown in fig. 2) is received in the piston chamber 10 so as to be movable up and down. The valve needle 19 is arranged below the control piston 18 and can be moved up and down together with the control piston 18 in order to release or close an injection hole of the fuel injector. The chamber below the valve needle 19 is always connected to high fuel pressure.

When the magnet armature of the actuator 16 is not activated, the magnet armature is pressed downward by the spring, so that the ball closes the oil drain opening below it. The external high-pressure oil enters the control chamber 11 through an oil inlet hole (not shown) of the control chamber. The high pressure of the fuel in the control chamber 11 acts on the end face of the control piston 18, so that the needle is subjected to a resultant downward force, which closes the injection openings of the injection nozzle. When fuel injection is required, the electromagnet is triggered, the actuator 16 is sucked up by the electromagnetic force generated by the electromagnetic field, so that the armature moves upwards together with the ball, and the oil drain hole below the ball is released. The fuel pressure in the control chamber 11 decreases. The high pressure acting on the valve needle 19 moves the valve needle 19 and the control piston 18 together upward, so that the injection holes are opened and high-pressure fuel is injected into the combustion chamber of the internal combustion engine.

When the control piston 18 and the needle 19 are lifted upwards together, the high-pressure fuel in the control chamber 11 is forced outwards, through the drain opening into the upper cavity 12 and back into the fuel tank via the return channel 13 and the drain 14. On the other hand, high-pressure fuel can leak into the piston chamber 10 through the control mechanism and the gap between the nozzle partners, which is likewise returned to the tank via the return line. To this end, according to the invention, a transverse or substantially perpendicular oil outlet 14 extends through the longitudinal oil return channel 13 up to the opening into the piston chamber 10 in order to introduce the fuel in the piston chamber 10 into the oil return line. Furthermore, there may be leakage between the control piston 18 and the nozzle needle and the corresponding chamber, and in order to conduct the leaked fuel back into the tank, the oil return channel 13 extends downwards, connecting with the nozzle needle chamber substantially at the interface between the control piston 18 and the nozzle needle 19.

Compared with the prior art, according to the utility model discloses a sprayer has saved additional, need to the horizontal hole of outer seal through the oil return circuit in the rebuild sprayer body, has reduced component quantity and manufacturing procedure, has reduced the leakage risk, has reduced the manufacturing cost of sprayer and has improved the safety in utilization.

Claims (10)

1. Fuel injector for injecting fuel into a combustion chamber of an internal combustion engine, comprising a control piston (18), wherein the control piston (18) is guided in a piston chamber (10) so as to be longitudinally movable and wherein the control piston (18) delimits with one end face a control chamber (11), wherein the control chamber (11) is connected on the side facing away from the control piston (18) to a cavity (2) via a drain opening, wherein the control piston (18) is operatively connected at the other end to a nozzle needle (19) of the fuel injector in such a way that the nozzle needle (19) can execute an opening movement in the longitudinal direction of the fuel injector, which releases the injection opening or a closing movement, which closes the injection opening, wherein a return channel (13) is formed inside the fuel injector, wherein the return channel (13) leads out of the cavity (2) and is connected to a return line of the internal combustion engine via a drain opening (14), characterized in that the oil outlet (14) extends into the injector as far as into the piston chamber (10).

2. Oil injector according to claim 1, characterized in that the oil return channel (13) opens at the interface of the control piston (18) and the nozzle needle (19) at the side facing away from the cavity.

3. Injector according to claim 1 or 2, characterized in that the return channel (13) extends in the longitudinal direction of the injector.

4. A fuel injector according to claim 1 or 2, characterized in that the oil discharge port (14) extends in a lateral direction of the fuel injector.

5. Fuel injector according to claim 1 or 2, characterized in that an actuator (16) for handling the longitudinal movement of the control piston is arranged in the cavity (2).

6. Fuel injector according to claim 5, characterized in that the actuator (16) is configured as an electromagnetic actuator, the drain opening being closable or releasable by means of a movement of an armature of the electromagnetic actuator.

7. Injector according to claim 1 or 2, characterized in that the control chamber (11) is connected to a filling control port, so that the control chamber (11) can be alternately loaded with high-pressure fuel or low-pressure fuel.

8. A fuel injector as claimed in claim 1 or 2, characterized in that the fuel injector is configured as a common rail fuel injector.

9. Fuel injection system comprising a fuel injector according to one of the preceding claims.

10. Internal combustion engine comprising a fuel injection system according to claim 9.

Images