JP2003504553A - Fuel injection valve - Google Patents

Abstract

(57) [Summary] The present invention relates to a fuel injection valve for an internal combustion engine, which is provided with a valve member (1) slidable in an axial direction in a guide hole of a valve body (2). The valve member has a valve sealing surface (3) at an end on the combustion chamber side, and the valve sealing surface has a high-pressure passage (6) in the valve body (2) and at least one injection port (5). Cooperates with a valve seat (4) formed at the end of the guide hole on the combustion chamber side and controls a discharge control passage (7) in the valve member (1). The high pressure passage (6) can communicate with the relief chamber when the valve member (1) is lifted from the valve seat (4) through the discharge control passage, and the discharge control passage is provided. It is of the type in which the passage is formed by a blind hole starting from the end of the valve member (1) on the combustion chamber side. In order to improve the injection characteristics of the fuel injection valve, a throttle (8) having a constant throttle cross section is formed in the combustion chamber side end of the valve member (1).

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a fuel injection valve for an internal combustion engine, which is provided with a valve member that is slidable in the axial direction within a guide hole of a valve body, and the valve member is located on the combustion chamber side. Has a valve sealing surface at the end of the guide hole at the combustion chamber side end of the guide hole for controlling the communication between the high pressure passage in the valve body and the at least one injection port. A discharge control passage is provided in the valve member in cooperation with the formed valve seat, and the high pressure passage is relieved when the valve member is lifted from the valve seat through the discharge control passage. A type which can communicate with the chamber and whose discharge control passage is formed by a blind hole starting from the end of the valve member on the combustion chamber side.

A fuel injection valve of this kind is known from DE-A 19623581. In this known fuel injection valve, the intermediate chamber between the valve member and the valve body acts as a throttle above the valve seat and the valve sealing surface. The throttle cross-section varies with respect to the position of the valve member with respect to the valve body.

An object of the present invention is to provide a fuel injection valve with improved injection characteristics that is simple in construction and can be manufactured inexpensively. Moreover, a method of manufacturing a valve member for a fuel injection valve of this kind is provided.

This problem is a fuel injection valve for an internal combustion engine, which is provided with a valve member which is slidable in an axial direction in a guide hole of a valve body, and the valve member is provided on the combustion chamber side. It has a valve sealing surface at the end, which valve sealing surface is formed at the combustion chamber side end of the guide hole for controlling the communication between the high pressure passage in the valve body and the at least one injection port. And a discharge control passage is provided in the valve member, and the high pressure passage is provided through the discharge control passage when the valve member is lifted from the valve seat. Of the type in which the discharge control passage is formed by a blind hole starting from the end of the valve member on the side of the combustion chamber, a constant throttle is provided in the end of the valve member on the side of the combustion chamber. This is solved by the fact that a diaphragm having a cross section is formed. The advantage provided by this throttle is that the high pressure prevailing at the end of the valve member on the combustion chamber side is changed slowly during opening and closing of the injection valve. This avoids pressure shocks that cause damage to the fuel injection valve. Furthermore, the fuel injection valve according to the invention offers the same advantages as described in DE-A 19623581.

One particular embodiment of the invention provides that a throttle hole is provided in the end of the valve member on the combustion chamber side, the throttle hole opening in the blind hole and the diameter of the throttle hole. Is clearly smaller than the diameter of the blind hole. The diameter of the throttle hole is preferably from 0.1 mm
It is 0.3 mm. The throttle hole can be realized simply and inexpensively by the method described later.

Another special embodiment of the invention is characterized in that the throttle hole extends axially in the valve member. This ensures that the chamber in the area of the nozzle is in constant communication with the relief chamber.

A further special embodiment of the invention is characterized in that the throttle hole extends obliquely to the longitudinal axis of the valve member and opens below the valve seat edge. By arranging the opening of the throttle hole below the valve seat edge, it is ensured that the high pressure passage does not communicate with the relief chamber when the fuel injection valve is closed.

In the method of manufacturing the valve member for the fuel injection valve described above, the above-mentioned problems are solved by the following working steps. That is, a) the valve member with the blind hole is closed at the end on the combustion chamber side by circular kneading / push-in hammering, and b) the connection to the blind hole in the valve member is made by drilling.

An advantage of this method according to the invention is that it can be used with valve elements of conventional fuel injection valves.

Further advantages, features and details of the invention will be apparent from the following description, in which various embodiments of the invention are described in detail with reference to the drawings. In that case, each of the features mentioned in the claims and in the description below has the sophistication of the invention by itself or in any combination.

In a first embodiment of a fuel injection valve according to the invention shown in FIG. 1 for an internal combustion engine, a piston-shaped valve member 1 is axially slidable in a guide hole of a valve body 2. You are being guided. In that case, the cylinder-shaped valve element 2 projects at its free end into a combustion chamber, which is not shown in detail in the internal combustion engine to be supplied. The valve body 2 bears at its other end, which is formed as a flat end face, against an intermediate plate, which is followed by a spring chamber which serves to receive a return spring.

The valve member 1 has a valve sealing surface 3 at its end on the combustion chamber side, and this valve sealing surface is formed as a conical sealing surface in this embodiment. The valve sealing surface 3 is the valve body 2
Cooperates with a valve seat surface 4 formed in the shape of a hollow cone at the end on the combustion chamber side. A valve seat edge 10 is formed on the valve sealing surface 3.

An injection port 5 is provided at the tip of the valve body 2, and the fuel to be injected can reach the combustion chamber of the internal combustion engine through this injection port. A high pressure passage 6 is formed between the valve body 2 and the valve member 1. The high-pressure passage 6 communicates with a fuel high-pressure pump that supplies high-pressure fuel to the fuel injection valve via an injection conduit.

A discharge control passage 7 is provided in the valve member 1 for the decelerated opening stroke movement of the valve member 1. The discharge control passage 7 enables communication between the high pressure passage 6 and the pressure relief chamber during the opening stroke movement of the valve member 1. A throttle hole 8 is formed at the end of the discharge control passage 7 facing the injection port 5. The vertical axis of the throttle hole 8 coincides with the vertical axis of the discharge control passage 7. The diameter of the throttle hole 8 is significantly smaller than the diameter of the discharge control passage 7.

The second embodiment of the fuel injection valve according to the present invention shown in FIG. 2 is similar to the first embodiment shown in FIG. For simplicity, the same parts have the same reference numerals. The above description of FIG. 1 is incorporated to avoid repetition. The difference between the first embodiment and the second embodiment is that the second embodiment shown in FIG. 2 is provided with an obliquely extending throttle hole 9 instead of the axial throttle hole. . An obliquely extending throttle hole 9 opens into the valve seat surface 3 below the valve seat edge 10.

The fuel injection valve according to the present invention functions as follows. In other words, in the closed state, the valve member 1 is kept in contact with the valve seat surface 4 by the return spring of the valve member 1. In this state, the injection port 5 is closed with respect to the high pressure passage 6.

By the start of the injection process, the fuel discharged by the high pressure pump reaches the high pressure passage 6 and lifts the valve member 1 from the valve seat surface 4 against the force of the return spring. Then, the fuel under high pressure reaches the combustion chamber of the internal combustion engine through the opening-controlled flow cross section between the valve sealing surface 3 and the valve seat surface 4 and the injection port 5. During the opening stroke movement of the valve member 1, a part of the fuel flows into the pressure relief chamber through the throttle holes 8 or 9 and the discharge control passage 7. This slows the opening stroke movement of the valve member 1. This deceleration favors the preparation of fuel in the combustion chamber.

When the maximum opening stroke position of the valve member 1 is reached, the flow cross section that connects the discharge control passage 7 and the pressure relief chamber is closed, so that the total amount of fuel supplied reaches the combustion chamber. .

The injection ends in a known manner due to the pressure drop in the high-pressure passage 6. The valve member 1 again contacts the valve seat surface 4 by the preload force of the return spring. During the closing stroke movement of the valve member 1, part of the fuel flows out through the throttle holes 8 or 9 and the discharge control passage 7, which increases the closing stroke speed.

In FIG. 3 a valve member 1 with a blind hole 11 can be seen. A valve member 1 of this kind can be used as a starting member for the manufacture of the valve member according to the invention. Circular kneading and plunging hammering close the open end of the blind hole 11, as seen in FIG. Furthermore, the free end 12 of the valve member 1 is formed so as to taper towards the tip and with the valve seat edge 10. In another working step, the valve member shown in FIG. 4 is perforated at the closed end.

5 and 6 show different throttle holes 8 depending on the working direction of the drill tool.
It is shown that and 9 are formed at the free end 12 of the valve member 1. Finish drilling at the free end 12 of the valve member 1 is performed with a drill diameter of 0.1 mm to 0.3 mm.

[Brief description of drawings]

[Figure 1]   It is the figure which carried out the longitudinal section of the fuel injection valve by a 1st embodiment.

[Fig. 2]   It is the figure which carried out the longitudinal section of the fuel injection valve by a 2nd embodiment.

[Figure 3]   It is a figure which shows the free end of the valve member in a starting state.

[Figure 4]   FIG. 4 shows the valve member from FIG. 3 after the first working step.

[Figure 5]   It is a figure which shows the valve member by which the finishing process was carried out by 1st Embodiment.

[Figure 6]   It is a figure which shows the valve member by which the finishing process was carried out by 2nd Embodiment.

─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Gungel Jürtseven             Turkey Mudanya / Bursa Muni             Le Passa OK Gul Cite             Shea Brock Dale 19 F term (reference) 3G066 AA07 AD12 BA06 BA55 CC14                       CC18 CC63 CE13

Claims (5)

[Claims] 1. A fuel injection valve for an internal combustion engine, comprising a valve member (1) axially slidable in a guide hole of a valve body (2), which valve member It has a valve sealing surface (3) at the end on the combustion chamber side, and this valve sealing surface communicates between the high pressure passage (6) in the valve body (2) and at least one injection port (5). A valve seat (4) formed at the end of the guide hole on the combustion chamber side, and an exhaust control passage (7) is provided in the valve member (1). The high-pressure passage (6) can communicate with the relief chamber when the valve member (1) is lifted from the valve seat (4) through the discharge control passage, and the discharge control passage is formed by the valve member (1). In the type formed by a blind hole starting from the end on the combustion chamber side of (1), a consequent is formed in the end on the combustion chamber side of the valve member (1). A fuel injection valve, characterized in that a throttle (8, 9) having a tangential throttle crossing is formed. 2. A throttle hole (8, 9) is provided in the end of the valve member (1) on the combustion chamber side, and the throttle hole is opened in the blind hole (7) and 2. The fuel injection valve according to claim 1, characterized in that the diameter of the holes is significantly smaller than the diameter of the blind holes (7). 3. Fuel injection valve according to claim 2, characterized in that the throttle hole (8) extends axially in the valve member (1). 4. The throttle hole (9) extends obliquely to the longitudinal axis of the valve member (1) and opens below the valve seat edge (10).
The fuel injection valve described. 5. A method for producing a valve member (1) for a fuel injection valve according to any one of claims 1 to 4, comprising the following working steps: a) blind hole (11) ) Is closed at the end on the combustion chamber side by circular kneading / pushing hammering, and b) communication (8) to the blind hole (11) in the valve member (1) by drilling. , 9) is manufactured, and a manufacturing method of a valve member for a fuel injection valve.