JPH01224457A - High pressure fuel injection device of engine - Google Patents

Abstract

PURPOSE:To facilitate installation of device body by furnishing the tail of a body with a fuel supply hole, which is in communication with a pressure accumulator chamber and a small chamber, and a fuel return hole in communication with the valve mouth of this small chamber, and by providing them with opening facing backward. CONSTITUTION:In a device body 1, fuel in a tank 5 is pressurized by a pump 4 and sent by pressure to a supply hole 3, and then is injected from a jet 2. An injection valve element 13 is held in the body 6 so as to be facing a pressure accumulating chamber 7 and a small chamber 17 with its front and rear. A valve element 35 driven by an electric magnet 9 is installed so as to open and close the valve mouth 28 of this small chamber 17. A fuel supply hole 3 in communication with these chambers 7, 17 and a fuel return hole 29 in communication with the valve mouth 28 are provided at the tail of the body 6. Those holes 3, 29 shall be open backward and connected to the tank 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-pressure fuel injection device for an engine used, for example, in a high-speed diesel engine.

[Conventional technology]

In recent years, in diesel engines, technology for electrically controlling fuel injection has been attracting widespread attention due to demands for lower fuel consumption in the -layer and purification of exhaust gas. A fuel injection device employing this type of technology is disclosed in, for example, Japanese Patent Laid-Open No. 62-282164 (title of invention: injector). This is a so-called balanced type that applies fuel pressure before and after the injection valve body that opens and closes the fuel injection port, and is introduced into the case from the fuel supply port opened laterally on the side of the case. While the fuel injection port is closed by the pressure of the fuel, during fuel injection, the valve body operated by an electromagnet opens the valve port to release the pressure on the back of the injection valve body, and the injection valve body is moved back.
Configured to inject fuel.

[Problem to be solved by the invention]

However, in this structure, when the fuel injection device is attached to the engine body by screw action, there are manufacturing errors in these parts, so the direction of the fuel supply port can be kept constant by finely adjusting the thickness of the shim. must be done. For this reason, there was a problem in that the installation work was extremely complicated. The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a high-pressure fuel injection device for an engine that can be easily attached to an engine body.

[Means to solve the problem]

The high-pressure fuel injection device according to the present invention has a fuel supply port that communicates with the pressure accumulation chamber and the small chamber at the rear end of the body that has a pressure accumulation chamber and a small chamber into which pressurized fuel is introduced, and a fuel supply port that releases the pressure of the small chamber. A fuel return port is provided that communicates with the valve port.
Both of these mouths are opened to the rear.

[Effect]

In the present invention, the fuel supply port and the fuel return port are always directed toward the rear without being affected by manufacturing errors in the fuel injection device or the like.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal cross-sectional view showing a high-pressure fuel injection device for an engine according to the present invention, and FIG. 2 is a plan view of the same, and in these figures, the fuel injection device, designated as a whole by reference numeral 1, is generally formed into a substantially cylindrical shape. has been done.

A fuel injection port 2 is opened at the front end of this fuel injection device 1, and a fuel supply port 3 is opened rearward along the axial direction at the rear end. Fuel pressurized to a high pressure (for example, about 500 kg/cJ) is pumped from a fuel tank 5 to this fuel supply port 3 by a fuel pump 4 .

Reference numeral 6 denotes a body, which has a generally cylindrical shape with a small diameter at the front and a large diameter at the rear, and a hollow front box 8 which has a pressure accumulation chamber 7 inside. It consists of a rear part 10 that covers the rear of the box 8 and the outside of the electromagnet 9, and is attached to the engine main body (not shown) using a male screw 11 provided on the outer peripheral surface of the front box 8. A disc-shaped inner lid member 12 that defines the inside of the body 6 from front to back is held between the front box 8 and the rear part 10. In the center of the inner lid member 12 is a shaft hole 14 that holds the rear part of the injection valve body 13 that opens and closes the fuel injection port 2.
is provided. The rear part of the injection valve body 13 is formed to have a larger diameter than the front part. On the other hand, the front part of the injection valve body 13 is held by having the front end part 13a inserted into the nozzle tip 15 screwed onto the front end of the front box 8. A shim 16 is interposed between the nozzle tip 15 and the front box 8 to adjust the lift amount of the injection valve body 13. 17 is a small chamber formed by the bottom of the shaft hole 14 and the rear end surface of the injection valve body 13 and having an extremely small volume. That is, the injection valve body 13 is housed in the body 6 and is held movable in the axial direction so that the front part faces the pressure accumulation chamber 7 and the rear part faces the small chamber 17. A flange portion 13b is protruded approximately at the center, and an injection valve body 13 is provided between the spring receiver 18, which is locked by the flange portion 13b, and the front surface of the inner lid member 12. A compression coil spring 19 is elastically loaded to bias the mouth 2 in the direction of closing.

The fuel supply port 3 is arranged near the outer periphery of the front box 8, which is offset from the center. Reference numeral 21 denotes vertical fuel passages 2 and 22 which are opened in the fuel supply port 3 and pass through the peripheral wall of the rear part 10 in the axial direction.
is a horizontal fuel passage that penetrates in the radial direction between the shaft hole 14 of the inner lid member 12 and the outer peripheral surface. These fuel passages 21.22
are communicated with each other through a communication passage 23. Lateral fuel passage 2
2 communicates with a central chamber 25 provided at the rear of the injection valve body 13 via a communication hole 24 . The central chamber 25 is arranged on the axis of the injection valve body 13 and communicates with the small chamber 17 through an orifice of a first orifice member 26 made of brass and press-fitted into the rear end of the injection valve body 13 . A second orifice member 27 is made of brass and is screwed onto the front surface of the inner lid member 12, and communicates the horizontal fuel passage 22 with the pressure accumulation chamber 7 via the orifice. Therefore, the pressurized fuel supplied to the fuel supply port 3 is introduced into the pressure accumulation chamber 7 and the small chamber 17 via these fuel passages and orifices. 28
A valve port communicates between the small chamber 17 and the inside of the rear part 10 and releases the pressure inside the small chamber 17 into the rear part 10, and is arranged on the axis of the inner lid member 12. And inside the rear part 10 is the fuel return port 2.
At 9, it communicates with the outside world and farts. The fuel return port 29 is a tube press-fitted into the rear end of the rear part 10, and is formed to open rearward along the axial direction, and is connected to the fuel tank 5.

The electromagnet 9 includes a core 31 having a shaft hole in the center, an electromagnetic coil 32 wound around the core 3I, and a cylindrical coil fitted around the electromagnetic coil 32 and the core 31 so as to cover their outer sides. The yoke 33 has a cylindrical shape as a whole.

35 is a valve body interposed between the electromagnet 9 and the valve port 28 to open and close the valve port 28. As shown in FIG. 3, the valve body 35 is
The valve stem extends toward the electromagnet 9, is inserted into the shaft hole of the core 31, and is held so as to be movable forward and backward. Further, a disk-shaped armature 36 is caulked and fixed to the outer peripheral portion of the valve body 35, facing the core and the yoke 31,33. That is, the armature 36 has a concave portion 37 into which the valve body 35 is fitted with its front end protruding, and is fixed to the valve body 35 by plastically deforming the opening edge of the concave portion 37 in the inner diameter direction. be done.

The yoke 33 is integrally formed with a small diameter coil covering portion 33a that covers the outside of the electromagnetic coil 32 and a large diameter fixed portion 33b that is screwed into the inner lid member 12.
The front end surface of b is in contact with the inner lid member 12 via a shim 41. Then, the coil covering portion 33a and the fixed portion 33
The intermediate part between the armature and the armature suction part 3 protrudes inward so that the diameter becomes smaller toward the front.
3c is formed. 42 is an outer annular groove provided on the outer peripheral surface of the yoke 33 near the armature 36, and 43 is an inner annular groove similarly provided on the inner peripheral surface near the armature 36. Specifically, these annular grooves are provided between a portion extending from the armature suction portion 33c to the coil covering portion 33a and a fixed portion 33b which is an outer portion thereof. More specifically, the outer annular groove 42 is interposed between the coil covering part 33a and the fixed part 33b, the inner annular groove 43 is interposed between the armature adsorption part 33c and the fixed part 33b, and the yoke 33 The cross-sectional area of the armature suction portion 33C and the portion extending from the coil covering portion 33a to the fixed portion 33b is reduced. Although not shown in the drawings, members such as the yoke 33 are provided with a communication hole through which the fuel return port 29 and the valve port 28 communicate with each other.

A compression coil spring 45 constantly presses the valve body 35 toward the valve port 28 and compresses and deforms itself in the axial direction. This spring 45 is loaded into a recess 46 provided on the axis of the core 31 on the side opposite to the armature. 47 is valve body 3
A spring receiver 48 provided at the rear end of the spring 5 is an adjustment screw that is screwed into the opening edge of the concave portion 46 from the rear and adjusts the elastic force of the spring 45 depending on the amount of screwing. '51
is an external connection terminal member for connecting the electromagnetic coil 32 of the electromagnet 9 to an external power source. This terminal member 51 is formed in the shape of a spring screw shaft and extends through the rear wall of the rear section 10 at the collar portion 5.
1a and a nut 52, and a terminal 53 is held between the nuts 52 and 52 stacked in the axial direction. 54 is a sealing material that seals between the terminal member 51 and the rear section 10.

In the high-pressure fuel injection device for the engine configured in this manner, fuel is supplied from the fuel supply port 3 to the pressure accumulation chamber 7 and the small chamber 1.
7 and is injected from the fuel injection port 2,
The fuel is returned from the fuel return port 29. That is, when no voltage is applied to the electromagnet 9, the pressures in the pressure accumulation chamber 7 and the small chamber 17 are balanced, so the fuel injection port 2 is kept closed. On the other hand, when voltage is applied to the electromagnetic coil 9, a magnetic flux is generated around the coil 32 that detours to the armature 36, so the valve body 35 retreats from the valve port 28.
The pressure inside the small chamber 17 is rapidly reduced. As a result, the injection valve body 1
3 is moved back by the pressure of the fuel in the pressure storage chamber 7, the fuel injection port 2 is opened, and fuel is injected. Then, when the voltage application to the electromagnet 9 is removed, the pressure in the small chamber 17 with a small volume increases momentarily and presses the injection valve body 13, so that the fuel injection port 2 is closed.

Further, since the rear end portion of the rear section 10 of the body 6 is provided with a fuel supply port 3 and a fuel return port 29 that are open to the rear, when installing the fuel injection device 1 to the engine body, the fuel injection device 1 and the engine The fuel supply port 3 and the fuel return port 29 can always be directed rearward without being affected by manufacturing errors in the main body or the washer inserted between them.

Therefore, the work of aligning the directions of the fuel supply port 3 and the fuel return port 29 can be simplified.

〔Effect of the invention〕

As explained above, according to the present invention, at the rear end of the body having the pressure accumulation chamber and the small chamber into which pressurized fuel is introduced, there is a fuel supply port communicating with the pressure accumulation chamber and the small chamber, and a fuel supply port communicating with the pressure accumulation chamber and the small chamber. A fuel return port is provided that communicates with the escape valve port, and both ports are opened to the rear, so the fuel supply port and fuel return port can always be moved to the rear without being affected by manufacturing errors in the fuel injection device, etc. can be directed.

Therefore, since it is not necessary to align the directions of the fuel supply port and the fuel return port, the installation of the fuel injection device can be facilitated.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a high-pressure fuel injection device for an engine according to the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a sectional view showing a valve body. 3...Fuel supply port, 6...Body, 7...
・Accumulation chamber, 9...electromagnet, 10...rear section, 17
... Small chamber, 28 ... Valve port, 29 ... Fuel return port, 35 ... Valve body. Patent applicant Yamaha Motor Co., Ltd.

Claims (1)

[Claims] A body having a pressure accumulation chamber and a small chamber into which pressurized fuel is introduced, and an injection valve body held within the body so that its front part faces the pressure accumulation chamber and its rear part faces the small chamber, and opens and closes a fuel injection port. A high-pressure fuel injection device comprising a valve body operated by an electromagnet that opens and closes a valve port for releasing pressure in the small chamber, the fuel supply port communicating with the pressure accumulation chamber and the small chamber at the rear end of the body, and the valve port. A high-pressure fuel injection device for an engine, which is provided with a fuel return port that communicates with the engine, and has both ports opened rearward.