JPS6025627B2 - fuel injection mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection mechanism in an internal combustion engine, preferably of the compression ignition type.

Fuel injection mechanisms for supplying fuel to compression-ignition internal combustion engines are well known in the art and are typically located at the end of a tubular holder and held therein by a cap nut. includes a valve assembly.

FIG. 4 shows a side view of such a conventional fuel injection mechanism.

In this figure, the tubular holder 2 has a skirt portion 4 around the valve assembly. The cap nut 6 has a thread on its inner circumferential surface for engaging the holder 2, and also has a thread on its outer circumferential surface. is fixed in the hole. The holder 2 also forms a fuel inlet that communicates through a passage 9 with a chamber 8 in which the valve assembly is installed.

In use, the fuel inlet is connected to the fuel injection pump by a pipe. In order to make the fuel injection mechanism compatible with smaller internal combustion engines, it is necessary to reduce its diameter.

However, it is difficult to reduce the diameter of the fuel injection mechanism due to the need for screw connections between the cap nut 6 and the holder 2 and between the cap nut 6 and the wall of the hole in which the injection mechanism is installed. Ta. The object of the invention is to provide a fuel injection mechanism that can be adapted to smaller internal combustion engines by reducing its diameter.

According to the invention, in an internal combustion engine having a cylinder head having a through hole, there is provided a fuel injector disposed on a step provided in the hole, the fuel injector comprising a housing having a seat; a valve member that slides within the housing and cooperates with the seat to control fuel from the fuel injector in use; an enlarged end portion maintained in flow communication with the fuel injector; a member threadably engaged with the cylinder head; the member threadably engaged with the cylinder head and the housing each have support portions, and these support portions are connected to the fuel supply pipe; The fuel injector engages axially opposed portions of the enlarged end portions of the tube to capture the enlarged end portions therebetween, and the fuel injector acts through the enlarged end portion of the fuel supply tube. A member that screws with the head presses against the solder that engages with the stepped portion of the hole. The fuel injection side is obtained.

The part threadedly engaged with the cylinder head has the function of retaining the fuel injection mechanism in the bore in the cylinder head and creating a fuel-tight seal, preferably by a step at the bottom of the bore, and a high-pressure pump. It has the function of holding the connecting fuel inlet pipe in place.

The mechanism of the present invention includes only one screw connection relationship between the cylinder head and the member that screws into the cylinder head, so it does not include one screw connection relationship as in the conventional example. The diameter of the hole in the engine cylinder can be made smaller compared to the engine cylinder.

Preferably, the hole passing through the cylinder head is formed with a step, and the fuel injector is configured to act on the step of the hole with respect to the member acting through the enlarged end portion of the fuel supply V-tube. Pressed into engagement.

In one embodiment, the member has a head portion and a threaded shank portion surrounding the fuel supply tube with a gap, and a support portion is provided in the head portion and the member is provided with a threaded shaft portion that surrounds the fuel supply tube with a gap. The end portion is received within the shaft portion.

In an alternative embodiment, the member has a head portion and a threaded shaft portion, and the reinforcement portion is disposed at or adjacent to an end of the shaft portion remote from the head portion. , can be established.

Either or both of the abutting portions are formed on a surface with a corner cut off.

The enlarged end portion of the fuel supply Kamakura tube is formed by an olive-shaped or egg-shaped section surrounding the end of the fuel supply tube, or the end of the fuel supply tube is flared outward. It can be formed by

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which: FIG.

Referring to FIG. 1, the illustrated fuel injection mechanism includes a fuel injector 10 disposed in a bore 11 in a cylinder head 12 of an engine, the fuel injector 10 being injected into the bore via a seal washer 13a. 1 is engaged with the stepped portion 13 of 1.

The fuel injector 10 has a housing 114 having two parts 15 and 16 that are sealingly engaged with each other to define a chamber within the housing 14. are doing. The housing part 15 has a fuel inlet 17 which fits into said chamber, and the housing part 16 has a vertical hole in which a povet valve member 18 is slidably received. The head of a valve member, such as a Pobet valve member 18, cooperates with a seat 19 in the housing portion 16 to control the flow of fuel into the engine combustion chamber 20, which opens at the narrow end in the bore 11. It is being done. The shank of the povet valve member 18 is dimensioned relative to the bore so that an annular space is defined between the stem and the side wall of the bore in the housing 16; , housing portion 16
It communicates with the chamber via a gateway 21 provided in the chamber.

A collar 22 is provided on the shaft, and the collar 22 is formed with a spiral groove. These grooves act to impart swirling motion to the fuel as it is injected from the fuel injector 10 to promote atomization of the fuel. The operation of the type of injection device described above is well known and therefore will not be described further. The end of the valve member 18 remote from its head is mounted with a spring receiver 23;
A spring 24 is housed in the chamber between the spring receiver 23 and the housing part 16. Spring 24 serves to prevent Z valve member 18 from rising away from seat 19. The fuel injection mechanism further includes a fuel supply pipe 26
The end of the fuel supply pipe 26 has an enlarged end portion 27Z formed by, for example, an oleaf-shaped member 27.

This olive-shaped member 27 is an annular piece of soft metal, for example copper, which slides over the fuel supply pipe 26 and when the member 28 screwed into the cylinder head 12 is tightened, the olive-shaped member 27 It engages the fuel supply pipe 26 and is strained to form a liquid-tight 2 seal. A section 28 that is threadedly engaged with the cylinder head 12 has a hole in its center, and a fuel supply pipe 26 is passed through this hole. The cylinder head screwing member 28 has a head portion 29 and a rattle portion 30 integrally formed therewith. The two-wheeled portion 30 is threaded on its outer surface, which threaded portion engages a corresponding threaded portion formed in the side wall of the hole 11.

The end of the shaft portion 30 remote from the head portion 29 is rounded to define a stop portion 31 . Fuel injection device 10
The housing 43 is also rounded in the area of the fuel inlet 17 so as to define the second support portion 32 .
The support portions 31, 32 engage axially opposite portions of said olive-shaped portion 27, so that the end of the fuel supply tube 62 is captured between them, whereby the fuel supply tube 2
6 is maintained in a continuous flow relationship with respect to the fuel inlet 17. On the one hand, the section 28 that screws into the cylinder head
and an olive-shaped member 27, on the other hand, the housing 14 and an enlarged end portion, e.g. an olive-shaped member 27.
A fluid-tight seal is created between the cylinder head and the cylinder head by the deformation of the olive-shaped member 27 as the member 28 that threads into the cylinder head is screwed downward. From the foregoing description, it can be seen that the threaded connection 28 with the cylinder head not only serves to connect the fuel supply pipe 26 to the fuel injection device 10', but also by acting on the olive-shaped member 27 and Press the device 10 through the member 27 to open the hole 1.
Its engagement with the step 13 in the bore 11 helps to secure the fuel injector 10 in place within the bore 11. The fuel injection mechanism shown in FIG. 2 is similar to that described above in connection with FIG. 1, and like parts are numbered with the previous reference numerals plus 100.

However, in this second embodiment, the shank portion 130 of the cylinder head threaded member 128 surrounds the end of the fuel injector 110 and the hole 111 is inserted into the cylinder head threaded member 128. A second step is formed to accommodate the. The olive-shaped member 127 is connected to the abutting portion 13 provided on the housing 114 of the fuel injector 110.
2 and an abutment 133 provided on the head portion 129 of the threaded member 128. From a comparison of FIGS. 1 and 2, it will be appreciated that the mechanism of FIG. 2 occupies more axial space within the cylinder than that of FIG.

A modified version of the mechanism described above is illustrated in FIG.

In the embodiment of FIGS. 1 and 2, the housing part 1
5, 115 end and step part 13, 113 of hole 11, 111
Sealing between the two is performed by seal washers 13a and 113a. However, this type of arrangement can be replaced by that shown in FIG. In that of Figure 3,
The ends of body portion 150 are rounded to engage seat 151 directly. The seat 151 itself is spherical or substantially spherical, and its radius of curvature is greater than the radius of the end of the body portion 150, so that the body portion and the seat can be sealingly engaged with each other. In yet another modification (not shown), the olive-shaped tube is omitted and the end of the fuel-free V supply tube 26, 126 is extended outwardly from its tube wall. Expanded by

The structure described above has two tubes in the housings 14 and 114.
6, 126 and for securing the device 10, 110 within the hole 11, 111.

As a result, parts can be saved and the length of the fuel injectors 10, 110 in the vertical direction can be made shorter. In known constructions, the housing is threaded for engaging the bore and is provided with a head for receiving a wrench for tightening the housing within the bore to obtain the desired seal. The head must be accessed from the outside of the cylinder head, and the end of the head is provided with an attachment for a fuel supply pipe.

[Brief explanation of drawings]

Figure 1 is a side view of a compression ignition engine equipped with a first embodiment of the fuel injection mechanism according to the present invention; Figure 2 is a side view of a compression ignition engine equipped with a second embodiment of the fuel injection mechanism according to the present invention. Fig. 3 is a side view of a modified form of the fuel injection mechanism shown in Figs. 1 and 2; Fig. 4 is a side view of a conventional fuel injection system. . In the drawing, 10 is a "fuel injection device"; 11 is a "hole"; 12
is "cylinder head"; 14 is "housing": 18
is "valve member"; 19 is "seat"; 26 is "fuel supply pipe";
27 is an ``olive-shaped capital''; 28 is a ``member that screws into the cylinder head''; 31 and 32 are ``contact parts''. FIG,l,FIG. 2, F! G3, FIG. 4.

Claims (1)

[Scope of Claims] 1. A fuel injection mechanism for an internal combustion engine having a cylinder head having a through hole, the fuel injection device being arranged on a step provided in the hole, comprising: a housing having a seat; and a valve member sliding within the housing and cooperating with the seat to control fuel from the fuel injector in use; in flow communication with the fuel injector; a fuel supply tube having an enlarged end portion; a member threadably engaged with the cylinder head; and the member threadably engaging the cylinder head and the housing each having an abutment portion; an abutment axially engages an enlarged end portion of the fuel supply tube to capture the enlarged end portion therebetween, and the fuel injector acts through the enlarged end portion of the fuel supply tube. A fuel injection mechanism for an internal combustion engine, wherein the fuel injection mechanism is pressed into engagement with a step of the bore by a member threadedly mating with the cylinder head. 2. A member threadably engaged with the cylinder head is provided with a head portion and a threaded shaft portion, an abutment portion is provided on the head portion, and an end of the fuel injector is housed within the shaft portion. A fuel injection mechanism according to claim 1. 3. The member that is threadedly engaged with the cylinder head has a head portion;
2. The fuel of claim 1, having a threaded shaft portion, said abutment being provided at and adjacent an end of said shaft portion remote from said head. Injection mechanism. 4. Either one or both of the contact portions is formed by a surface with a corner cut off.
3. The fuel injection mechanism according to item 3 or 3. 5. The fuel injection mechanism according to any one of claims 1 to 4, wherein the enlarged end portion of the fuel supply tube is formed of an olive-shaped portion disposed on the tube. .