JPS6235058A - Fuel injector for reciprocating internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The invention relates to at least one cylinder, a fuel supply device, which is closed by a cylinder head and has a piston cooperating with the cylinder head to form a combustion chamber. includes at least one fuel injector connected to the device and including a nozzle member positioned in a bore in the cylinder head, the nozzle member being directed toward and into the combustion chamber. Create a directed jet of fuel J
: Relates to a fuel injection device for a reciprocating internal combustion engine having a head with a shaped nozzle hole.

Prior Art Previous devices of the aforementioned type include, for example, the DE-PAP35
In the cylinder head proposed in 01 236.6 (P, 5925), the head of the nozzle member, including the nozzle hole, projects into the combustion chamber and is therefore significantly exposed to the high temperatures therein. When the temperature of the combustion chamber rises above the melting point of the non-flammable components of the fuel, these components are welded into the combustion chamber.

Depending on the nature and composition of the fuel, especially in the case of diesel engines which are normally operated on heavy oil, non-flammable components, e.g. in the form of oil ash, will melt at the relevant temperatures and will not be present in the parts that protrude into the combustion chamber, e.g. nozzle parts. causes high-temperature corrosion at the outlet end of the

PROBLEM SOLVED BY THE HALO INVENTION It is an object of the invention to improve the device so that the outlet end of the nozzle member can be kept at an operating temperature below the melting point of the non-flammable components of the fuel. .

21 Means for solving the problem To this end, according to the invention, a hole-widening, scoop-shaped recess is made on the inner surface of the cylinder head and surrounds the head of the nozzle member containing the nozzle hole. , and the end of the head facing the combustion chamber is placed substantially opposite, for the combustion chamber, an imaginary reference plane constituted by the portion of the inner surface of the cylinder head adjacent to the recess, and the recess is located in the direction of the jet of fuel. is created by a surface portion extending a certain distance from an imaginary enclosing surface constituted by the path of .

According to the invention, the part of the nozzle member is recessed into a recess so that the end of the head is kept in a relatively cool zone outside the area of highest combustion temperature, thus Limiting the head surface temperature to a value below the melting point of the non-flammable components of the fuel most commonly used for engine operation. Similarly, especially in embodiments where the outlet end of the nozzle member is not cooled, the surface temperature of the head can be kept below the sticking temperature of the oil ash, which corresponds to the melting point of some of the non-flammable components of the fuel. , the non-flammable components are therefore prevented from accumulating in the head, thus reducing the risk of hot corrosion of the nozzle components.

In the case of an injection device comprising at least two nozzle members offset relative to each other about their longitudinal axis in the circumferential direction of the cylinder, the heating of the head of the retracted nozzle member of the invention can be particularly easily reduced. If the nozzle holes in the nozzle member are each oriented in the direction of the circumference of the cylinder towards an adjacent sector of the cross section of the cylinder, the working temperature at the outlet end is further reduced, and the recess is Starting from the passage for the nozzle members, each is at least approximately composite of the path of the jet of fuel and centered on the longitudinal axis, and less than the distance of each nozzle member from the longitudinal axis of the cylinder. Extending in the main direction, extending approximately tangent to an imaginary circle with a small radius.

The invention will now be described with reference to an embodiment shown schematically in the drawings.

In the illustrated embodiment, the reciprocating internal combustion engine is a longitudinally scavenged two-cycle diesel engine.

FIG. 1 shows a cylinder head 1 firmly attached by screws 2 to a cylinder liner 3 of a reciprocating internal combustion engine. The cylinder head 1 covers the top of a cylinder chamber 4 in which a piston 5 is vertically guided in a tightly sealed manner. The piston 5 in the rectangular position shown in FIG. 2 cooperates with the cylinder head 1 to bound the combustion chamber 4a;
Several fuel injection valves 6 (four in the figure) can be directed into the combustion chamber, which are connected to a fuel supply (not shown).

The valves 6 are threaded through the cylinder head 1 and are rotationally symmetrically offset relative to each other in a zone around the head 1 about the longitudinal axis 9 of the cylinder liner 3 . 6
The valve 6 has a fuel supply duct 7, a valve needle 8 cooperating with a conical valve seat, and a nozzle member 10 opening into the combustion chamber. Each nozzle member 10 is placed in a hole 17 in the cylinder head 1, and its head 10a facing the combustion chamber 4a has a jet of fuel directed into the chamber 4a.
A nozzle hole 11 is made so as to make a nozzle 2.

As shown in that embodiment, the cylinder head 1 has a chamber 4
It can have a central valve seat 13 cooperating with an outlet valve 14 connecting between the exhaust system a and the exhaust system of the internal combustion engine (not shown).

The cylinder head 1 has an inner surface 18 , ie a surface of rotation centered on the axis 9 . The surfaces 18 are made with trough-shaped depressions 15 each adjoining one of the passages 17' in the nozzle member and widening the passages towards the combustion chamber 4a. The members 10 are retracted into the recess 15 and the ends of their heads 10a facing the combustion chamber 4a lie substantially in the virtual reference plane 18a, which corresponds to a part of the rotating internal surface of the cylinder head 1 with respect to the combustion chamber. placed in the back.

The holes 11 in the nozzle members 10 are located in a limited sector (a quadrant in the example) approximately inside the circumference of the respective nozzle member 10 and across the adjacent combustion chamber in the circumferential direction of the cylinder. It is directed towards the quadrants of the surface. hole 1
1 indicates that the composite of the paths of the fuel jets 12 coming out of each nozzle 10 is along the vertical axis I! 9 and axis 9
It is placed substantially tangential to an imaginary circle 16 having a radius smaller than the distance of each nozzle member 1o from. Each depression 15 consists of a surface section located at a certain distance from the virtual surrounding surface (approximately conical in the example) constituted by the path of the jet 12 . This ensures that the flow of fuel exiting the hole 11 is not disturbed. There is also a corresponding reduction in heat transferred from the combustion gases to the head 10a, which is withdrawn into the recess 15 and outside the zone of hottest temperature. The holes 17 are each widened at one end by a depression 15 in the appropriate circumferential direction (corresponding in each case to a composite distribution of jets extending in the circumferential direction). In the illustrated embodiment, the peripheral portions of the imperforate member 10 are each 1. Tightly enclose the zone around the problem and hole 17
The cylinder 1 is shielded from the combustion gases in the chamber 4a by a portion of the cylinder head 1, which forms part of the chamber 4a. This applies in particular to the gases resulting from the combustion of the fuel leaving the member 10, on the one hand, and to the adjacent member 1 considered in the direction of fuel flow, on the other hand.
Avoiding direct contact with 1, thus preventing heating of the retracted nozzle member 10.

The head 10a, which is shown in FIG. It can protrude from 1 mm to 2 mm.

The device according to the invention is also suitable for other embodiments, for example without an outlet valve. Embodiments with a centrally located injection valve and/or several corresponding injection valves are also possible, for example. The nozzle member may also have holes distributed around the entire circumference and from which the jet of fuel exits in a conical shape, and the shape of the recess is in each case in the corresponding surrounding surface of the jet of fuel. Can be adapted.

[Brief explanation of the drawing]

FIG. 1 shows a cylinder head of a reciprocating internal combustion engine designed according to the invention, showing the internal parts partially cut away along line I--I in FIG. The cylinder head according to FIG. 1 and the internal combustion taI! shown in an enlarged partial section along the line If-[ of FIG. Related parts of I are shown. The code 1 in the drawing is "cylinder head", 2 is "screw",
3 is [cylinder liner], 4 is [cylinder chamber go,
4a is "combustion chamber", 5 is "r piston", 6 is "fuel injection valve", 7 is "fuel supply duct", 8 is "valve needle",
9 is the vertical axis of the cylinder, 10 is the nozzle member
, 10a is the "top of the nozzle member", 11 is the "nozzle hole", 12 is the "fuel jet", 13 is the "center valve seat", 1
4 is the "outlet valve", 15 is the "thorn-shaped recess", 16 is the "virtual circle J", 17 is the "hole in the cylinder head", 17'
18 is the "inner surface J of the cylinder head," and 18a is the "virtual reference surface."

Claims (2)

[Claims] (1) at least one cylinder, fuel supply device, closed by a cylinder head (1) and having a piston (5) cooperating with said cylinder head (1) to bound a combustion chamber (4a); at least one fuel injector (6) comprising a nozzle member connected to and placed in a bore (17) in said cylinder head (1), said nozzle member being connected to said combustion chamber (1). 4a
) and into the combustion chamber, the nozzle hole (
11), a reciprocating internal combustion engine fuel injection device having a head (10a) with and said nozzle hole (11)
surrounding the head (10a) of the nozzle member (10) and facing the combustion chamber (4a).
The end of 0a) is a virtual reference plane (for the combustion chamber (4a)) constituted by the part of the inner surface (18) of the cylinder head (1) adjacent to the recess (15).
18a) and located substantially opposite said recess (15).
Fuel injection device for a reciprocating internal combustion engine, characterized in that ) is created by a surface portion extending at a distance from an imaginary surrounding surface constituted by the path of the fuel jet (12). (2) its longitudinal axis (9) in the direction of the circumference of said cylinder;
2. An injection device according to claim 1, comprising at least two nozzle members (10) offset relative to each other around a , directed in the direction of the circumference of the cylinder towards adjacent sectors of the cross-section of the cylinder, and the recesses (15) starting from the passages for the nozzle members each direct a jet of the fuel. (
12) and centered on said longitudinal axis (9) and less than the distance of each said nozzle member (10) from said longitudinal axis (9) of said cylinder. A virtual circle with a small radius (16
), and extends in a main direction.