Fuel injection valve for internal combustion engines

Details Fuel injection valve for internal combustion engines Fuel injection valve for internal combustion engines

2000-07-07

2002-04-09

Hook, James (Department: 3752)

Fluid sprinkling, spraying, and diffusing

Fluid pressure responsive discharge modifier* or flow...

Fuel injector or burner

C239S533100, C239S533200, C239S585500

Reexamination Certificate

active

06367717

ABSTRACT:

PRIOR ART
The invention is based on a fuel injection valve for internal combustion engines. In a fuel injection valve of this type which is known from DE 195 23 243 A1, a piston-shaped valve member is guided so that the value member moves axially counter to a closing force in a guide bore of a valve body that protrudes with one end into a combustion chamber of the internal combustion engine to be fed. On an end face oriented toward the combustion chamber, the valve member has a conical valve sealing face, which the value uses to cooperate with a stationary, conical valve sealing face on the closed end of the guide bore in the valve body in order to control a through flow cross section to an injection opening into the combustion chamber of the internal combustion engine to be fed. In this connection, the injection opening is embodied as an injection bore leading from the valve sealing face. On the shaft, the valve member has a pressure shoulder which is engaged by a prevailing high fuel pressure in the opening direction of the valve member, counter to a closing force of a valve spring. The pressure shoulder of the valve member protrudes into a pressure chamber which is comprised of a cross sectional widening of the guide bore. This pressure chamber is fed by a pressure conduit which leads from an axial end face of the valve body remote from the combustion chamber and, because of its entry being disposed on the radial outside, extends diagonal to the axis of the valve body. This pressure conduit is connected to a high-pressure fuel pump by way of corresponding supply lines so that the high fuel pressure is introduced into the pressure chamber by way of the pressure conduit. Another document, U.S. Pat. No. 3,511,442, has disclosed a fuel injection valve of this generic type in which the pressure chamber is shaped radially at one end for an improved incorporation of the inlet opening of the pressure conduit.
However, the known fuel injection valves have the disadvantage that even with a slight off-center position of the valve member, some injection openings remain largely closed during the opening stroke of the valve member, particularly when there is a small valve member opening its stroke, while the supply to the remaining injection openings occurs in a largely unthrottled manner. This results in an uneven fuel injection at the fuel injection valve, which occurs to a greater degree with so-called hole-type nozzles. In the known fuel injection valves, the above-described effect is encouraged because the outlet opening of the pressure conduit is directed into the pressure chamber centrally on the valve member so that a lateral force acts dynamically on the valve member and presses the valve member to the side at one end and thus impairs the central position that the value member requires for a uniform injection jet formation.
ADVANTAGES OF THE INVENTION
The fuel injection valve for internal combustion engines according to the invention, has an advantage over the prior art that a central position of the valve member is assured under all operating conditions of the injection valve. This is achieved in a structurally advantageous manner by virtue of the fact that the outlet opening of the pressure conduit extending into the pressure chamber is pivoted eccentrically out of a common longitudinal intersecting plane with the inlet opening. The two longitudinal intersecting planes of the inlet opening and outlet opening of the pressure conduit, which intersect the longitudinal axis of the valve body, enclose an angle around the longitudinal axis of the valve body in relation to each other. This pivoting of the pressure conduit achieves the fact that the fuel jet flowing from the pressure conduit into the pressure chamber is directed off-center to the valve member and therefore does not introduce any lateral forces onto the valve member. Moreover, a rotational flow is thus advantageously produced in the pressure chamber, which reduces flow losses and therefore reduces a pressure drop between the pressure conduit and the pressure chamber.
In the exemplary embodiment, the position of the pressure conduit according to the invention is described in a so-called sac-less nozzle, but can also be used in all other types of fuel injection valves, for example blind hole nozzles, pintle nozzles, etc., in which a jamming or tilting of the valve member impairs the fuel injection at the injection openings. Since the above-described impairment has a particularly strong effect with small valve member stroke steps, it is also particularly advantageous to use the disposition of the pressure conduit according to the invention in fuel injection valves which operate with two opening stroke steps, for example, so-called two-spring nozzle holders.
Other advantages and advantageous embodiments of the subject of the invention can be inferred from the specification, the drawings, and the claims.


REFERENCES:
patent: 5207385 (1993-05-01), Turner
patent: 5449121 (1995-09-01), El-Darazi et al.
patent: 5465907 (1995-11-01), Hofmann
patent: 5718385 (1998-02-01), Fontell
patent: 5875973 (1999-03-01), Filiz et al.
patent: 5890660 (1999-04-01), Stevens
patent: 5899389 (1999-05-01), Pataki et al.

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