FUEL INJECTOR MOUNTING STRUCTURE

Field of invention;

The present invention relates to a " Fuel injector mounting structure " and more particularly to an improved fuel injection mounting structure having a fuel injector fitted on the intake pipe instead of the cylinder head.

Background of the invention:

Fuel injection systems are provided in internal combustion engines for obtaining more effective emission control, better fuel economy and, at the same time, continued high power output. In the common fuel injection systems used, fuel is injected into an intake air manifold. Fuel injection systems generally employ injector locator hole which is formed relative to the engine at the intake manifold on the cylinder head, to direct the received fuel towards the intake of the engine cylinder at appropriate timed intervals.

Mounting devices for mounting fuel injectors on engines have previously been employed which include a sleeve and seal means for directly affixing the injector to an engine element such as the cylinder head. Such mounting devices often require appropriate sealing configuration at the joints between the fuel injector and the engine cylinder head.

Normally, the injector is located in the cylinder head inlet path where a boss is provided with a bore and a sleeve is press fitted, where the injector is placed. The top portion of the injector is provided with fuel intake adapter, which is also provided with an extension so as to fasten the injector through a spacer and long metallic screw on to the cylinder head, The proximity of injector to combustion chamber when fitted on the cylinder head is very close, which increases the operating temperature of injector and associated parts significantly affecting its performance in the long run. The mounting of injector on cylinder head also increases design complexity and increases number of parts, thus reducing flexibility of design.

In the existing injector mounting structure, the fuel injector is mounted to a cylinder head of the engine through an intake pipe where the mounting member for fuel injector is fastened to the intake pipe. However, the known mounting structure for fuel injector on intake pipe is often problematic as the distance from the cylinder head to the outer end of the fuel injection valve is relatively large, and the projection amount of the fuel injection apparatus from the engine is large.

Hence, there exists a need for an improved mounting structure of the fuel injector fitted on intake pipe which allows to easily mount the fuel injector to the intake pipe and to improve the reliability and flexibility upon mounting the fuel injector thereto.

Object of the Invention:
The main objective of the present invention is to provide an improved mounting structure of the fuel injector fitted on intake pipe which allows to easily mount the fuel injector on to the intake pipe and to improve the reliability and flexibility upon mounting the fuel injector thereto.

Another objective of the present invention is to provide a fuel injector mounting structure fitted on intake pipe, which allows freedom of making multiple designs of possible engine variants with one common fuel injection and carburettor design.

Another objective of the present invention is to provide a fuel injector mounting structure which leads the entire engine including the fuel injection apparatus becomes compact.

Another objective of the present invention is to provide a fuel injector mounting structure which enhances proper fuel injection and effecting engine performance and emission control.

Summary of the invention:
In view of the foregoing, the present invention has been made, and an object of the present invention is to provide an improved mounting structure of the fuel injector fitted on intake pipe which allows to easily mount the fuel injector on to the intake pipe and to improve the reliability and flexibility upon mounting the fuel injector thereto.

It is also the objective of the present invention to provide a fuel injector mounting structure fitted on the intake pipe which allows for freedom of making multiple designs of possible engine variants with one common fuel injection and carburettor design.

The present invention relates to an improved fuel injection system having fuel injector fitted on intake pipe instead of the cylinder head. The intake pipe is provided with a bore tangential to axis of the intake pipe centre line. The centre line of the injector mounting bore and the centre line of the intake pipe intersect each other beyond the mounting face of the intake pipe on the cylinder head side. The injector bore is provided with a face perpendicular to the intake pipe and has concentrically made with a sufficient wall thickness to form a pipe like structure.

The injector mounting boss is provided with a flange shaped extension, extending below the top surface of the boss. The flange is provided with at least one hole parallel to the axis of the injector mounting bore. The flange is also provided with a U shaped cavity with an axis perpendicular to axis of the injector mounting bore.

A hole is provided in the flange to accommodate a nut in order to restrain it from rotating. The U shaped cavity is carved out from the side end of the flange such that the width of the cavity in the direction of nut insert is longer and extends substantially beyond the mounting hole.

According to the present invention, the fuel injector mounting structure has an injector mounting boss provided with a flange shaped extension extending below the top surface of the mounting boss in the intake pipe.

Further the scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Brief description of the drawings:

The features of this invention will now be described with reference to the drawings, which are intended to illustrate and not to limit the invention.

FIG. 1 is a sectional view showing the intake pipe, the cylinder head and the throttle body.

FIG. 2 is a front side view illustrating the mounting structure for a fuel injector on an intake pipe of an engine cylinder.

FIG. 3 is a cross-sectional view illustrating the fuel injector mounted on an intake pipe of engine cylinder.

Detailed description of the preferred embodiments:

The present invention will be described with reference to the accompanying
drawings.

FIG.1 shows the sectional view illustrating the intake pipe (2), the cylinder head
(13) and the throttle body (14).

FIG. 2 shows the front side view illustrating a fuel injector mounting system (100)
on an intake pipe (2) of an engine cylinder, such that an improved fuel injector
mounting system (100) is provided for an internal combustion engine that allows
for making multiple designs of possible engine variants with a common fuel
injection and carburettor design.

In order to attain the object described above, a fuel injector mounting system (100) is provided for an engine of a small size vehicle such as a motorcycle, which carries an engine having a cylinder. A fuel injector (1) for injecting fuel into a combustion chamber through the intake pipe (2) is disposed in the proximity of the cylinder head (13). A fuel injector mounting boss (5) is provided on an outer face of the intake pipe (2) for mounting the fuel injector on the said mounting boss (5).

According to the present invention, and referring to FIG. 3 which shows the cross-sectional view illustrating a fuel injector (1) mounted on an intake pipe (2) of engine cylinder, an improved fuel injection system includes a fuel injector (1) fitted on intake pipe (2) instead of cylinder head (13), wherein the intake pipe (2) is provided with an injector mounting bore (3) tangential to axis of the intake pipe centre line. The centre line of the injector mounting bore (3) and the centre line of the intake pipe (2) intersect each other beyond the mounting face of the intake pipe (2) of the cylinder head side. The injector mounting bore (3) is provided with a face perpendicular to the intake pipe (2) and has concentrically made a with sufficient wall thickness to form a pipe like structure.
The injector mounting boss (5) is provided with a mounting flange (6) with an extension extending below the top surface of the boss, the mounting flange (6) is provided with at least one hole parallel to the axis of the injector mounting bore (3).

The mounting flange (3) is also provided with a rotated U shaped cavity (7) with an axis perpendicular to axis of the injector mounting bore (3). The U shaped cavity (7) is larger than the hole provided in the mounting flange (6) to accommodate a nut (12) and restrain it from rotating. The U slot cavity (7) is carved out from the side end of the mounting flange (6) such that the width of the cavity (7) in the direction of nut insert is longer and extends substantially beyond the injector mounting bore (3).

A fuel intake adaptor (8) made of resin includes a bore to receive the fuel input end (9) of the fuel injector (1). The fuel intake adaptor (8) has a sprout (10) with a through hole projecting out from the body of the adaptor (8) with its axis perpendicular to the axis of the injector mounting surface (4). The sprout (10) is connected to the body of the fuel intake adaptor top end. The adaptor (8) body further extends towards the bottom to form a flange type structure so as to mount the fuel injector (1) and the whole fuel intake adaptor (8). The fuel intake adaptor (8) has a matching flange shape of that of intake pipe fuel injector mounting flange (6).

The flange of the fuel intake adaptor (8) is provided with at least one hole to allow a bolt (11) of suitable length. The fuel intake adapter (8) is also provided with radial ribs at required places to achieve rigidity and strength requirements. The fuel intake adaptor (8) is near circular in shape whereas the portion of the adaptor bore which receives fuel injector (1) is completely circular in shape. The portion of the adaptor below the fuel injector receiving bore is hollow and covers roughly 200 degrees for allowing the extended side portion of the fuel injector (1) to project out and fitting the electrical parts on to it.

The construction of the fuel injector (1) mounting has injector mounting boss (5) provided with a mounting flange (6) shaped extension extending below the top surface of the mounting boss (5) in the intake pipe (2) connected to the cylinder head, hence allowing the structure for making multiple designs of possible engine variants with one common fuel injection and carburettor design.

Also it is possible to ensure an improved mounting structure of the fuel injector fitted on intake pipe which allows to easily mount the fuel injector on to the intake pipe and to improve the reliability and flexibility upon mounting the fuel injector. Although this invention has been described in terms of a certain preferred embodiment, other embodiments apparent to those of ordinary skill in the art are also within the scope of this invention. Accordingly, the scope of the invention is intended to be defined only by the claims that follow.

We Claim:

1) A fuel injector mounting system (100) for an engine having a fuel injector (1) mounted on the intake pipe (2), an injector mounting flange (6) attached to a boss (5), an injector mounting bore (3) made in the boss (5) to receive the fuel injector (1)

wherein the improvement comprises of:

a cavity (7) provided in the flange (6) away from the bolt (11) clamping face and parallel to the said face with the cavity symmetrically disposed to the axis of the bolt (11).

2) The fuel injector mounting system (100) for an engine as claimed in claim 1, wherein the said cavity (7) is open from one side to accommodate a nut (12).

3) The fuel injector mounting system for an engine as herein substantially
described and illustrated with reference to the accompanying drawings