JPH10115272A - Fuel injection device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate such troubles as a fuel tube interfering with the other part and generating a flaw of a puppet valve when it is mounted, in a fuel injection device of CPI (center point injection) system. SOLUTION: A fuel injection device of CPI system is constituted such that a plurality of fuel tubes 6 are extended toward each cylinder from a solenoid valve 5, in a tip end thereof, a puppet valve 7 is mounted. Here, the solenoid valve 5 is mounted in surge tank part 2 of an intake manifold 1 of surge tank integral type, the fuel tube 6 is integrally formed with a branch pipe part 3 of the intake manifold 1, the puppet valve 7 is mounted in a mounting flange 4 relating to a cylinder head of the intake manifold 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection system for an internal combustion engine, and more particularly to a fuel injection control system using a solenoid valve. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CPI (Central Point Injection) type fuel injection device for an internal combustion engine having a valve mounted thereon.

[0002]

2. Description of the Related Art In a conventional general electronic fuel injection control device (EFI), fuel is supplied from a fuel pump to a delivery pipe arranged along a cylinder arrangement direction on a side of a cylinder head, and each cylinder is provided with a fuel pump. The injectors are arranged near the connection between the intake port and the intake manifold of the engine, and each injector is connected to a delivery pipe, and the fuel supply to each cylinder is controlled by opening and closing the injector by electronic control. .

[0003] However, there has been a problem that the configuration of the injector provided for each cylinder is complicated and expensive, and there are many components for arranging and connecting the delivery pipe, resulting in an increase in cost.

As a fuel injection device that can solve such a problem, a fuel injection device of the above-mentioned CPI (Central Port Injection) system is already known as disclosed in Japanese Patent Application Laid-Open No. 7-167012. As shown in FIG. 3, the CPI type fuel injection device includes a fuel valve 22 formed of a flexible tube such as a plurality of nylon tubes corresponding to the number of cylinders from a solenoid valve 21 as one fuel injector. When the fuel injection device is arranged, the solenoid valve 21 is mounted at an appropriate position on the intake manifold, and the poppet valve 23 at the tip of the fuel tube 22 is appropriately extended. It is attached to an intake manifold or a cylinder bed by a mounting bracket, and fuel is injected into an intake port of a cylinder head.

According to the CPI type fuel injection device,
Since fuel supply can be controlled to a plurality of cylinders with one solenoid valve 21 and piping can be easily performed with the fuel tube 22, the cost can be significantly reduced as compared with the case where an injector is used. Thus, the air-fuel ratio can be controlled with higher accuracy than in the carburetor system.

[0006]

However, since it is inevitable that the assembly of the fuel tube of the fuel injection device will vary during the piping of the fuel tube, it is difficult to flexibly connect the components of the intake system and other components such as accessories. There has been a problem that fuel tubes made of tubes may interfere and cause fuel leakage. There is also a concern that the fuel tube may be damaged when the poppet valve is attached.

[0007] In view of the above-mentioned conventional problems, the present invention provides a CP
It is an object of the present invention to provide a fuel injection device for an internal combustion engine, in which a fuel tube does not interfere with other components in the I-type fuel injection device and there is no possibility that the fuel tube is damaged when the poppet valve is mounted.

[0008]

According to the present invention, there is provided a solenoid valve connected to a fuel pump and controlled to open and close at a predetermined timing to control fuel supply to a plurality of cylinders, and extends from the solenoid valve to each cylinder. A plurality of fuel tubes are provided, and a poppet valve is attached to the tip of each fuel tube and injects fuel into each intake port of the cylinder head when the fuel pressure exceeds a predetermined value. Attached to the surge tank part of the integral intake manifold, the fuel tube is formed integrally with the branch pipe part of the intake manifold, the poppet valve is attached to the mounting flange for the cylinder head of the intake manifold. Eliminates the possibility of fuel leakage due to interference with other parts, By previously mounting the solenoid valve and poppet valve to the hold, and so as to greatly improve the assembling workability.

The fuel tube may be formed by casting a pipe material such as an iron pipe into an intake manifold made of an aluminum alloy casting or the like, or may be used to form the fuel tube at the time of forming an aluminum alloy casting or synthetic resin intake manifold. The fuel tube may be formed by casting the pipe material into the intake manifold as described above, but no fuel leakage will occur even if a cavity is formed in the intake manifold.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes an intake manifold integrated with a surge tank made of an aluminum alloy casting, 2 denotes a surge tank portion thereof, and 3 denotes a surge tank portion which extends from a surge tank portion 2 corresponding to a cylinder of an engine body. It is a branch pipe part. In the illustrated example, three branch pipe portions 3 are extended from the surge tank 2,
The distal end of each branch pipe 3 is integrally connected to a mounting flange 4 for a cylinder head (not shown).

Reference numeral 5 denotes a solenoid valve connected to a fuel pump (not shown). The solenoid valve 5 is mounted on one side surface of the surge tank 2 with mounting bolts 8. This solenoid valve 5
Is controlled by an engine control unit (not shown) in accordance with the operation state of the engine body, and controls the amount and timing of fuel supply. 5a is an inlet pipe connected to the fuel pump, 5b is a return pipe for returning excess fuel, and 5c is a control cable. Numeral 6 denotes a fuel tube formed of an iron pipe for supplying the fuel discharged from the solenoid valve 5 to each cylinder of the engine main body. As shown in detail in FIG. It is arranged in. Reference numeral 7 denotes a poppet valve configured to inject fuel when the fuel pressure exceeds a predetermined value.
Valve stay 9 on mounting flange 4 of intake manifold 1
Is mounted via. Specifically, the poppet valve 7 is mounted on the valve stay 9 or the poppet valve 7 is integrated with the valve stay 9, and the valve stay 9 is fastened to the boss portion 4 a protruding from the mounting flange 4 with the mounting bolt 10. It is attached by doing.

A plurality of short connection tubes 11 corresponding to the number of cylinders extend from the solenoid valve 5, and a short connection tube 12 is also provided from the base end of the poppet valve 7.
Has been extended. Further, both ends of the fuel tube 6 cast in the branch pipe portion 3 of the intake manifold 1 project outside. The fuel tubes 6 are connected to both ends of the connection tubes 11 and 12, respectively, to which quick nectars 13 made of synthetic resin are mounted.

According to the above configuration, when assembling the fuel injection device, the solenoid valve 5 is mounted on the surge tank 2 with the mounting bolts 8, and the poppet valve 7 is mounted on the mounting flange 10 with the mounting bolts 10 via the valve stays 9. 4 and these solenoid valve 5 and poppet valve 7
By connecting the connection tubes 11 and 12 with the two ends of the fuel tube 6 cast into the branch pipe portion 3 with the quick connector 13, the assembly of the fuel injection device to the intake manifold 1 is completed. Thus, the intake manifold 1 is assembled to the engine body, and the inlet pipe 5a of the solenoid valve 5 is connected to the fuel pump, the return pipe 5b is connected to the fuel tank, and the control cable 5c is connected to the engine control unit. Since the assembling is completed, the assembling workability can be greatly improved.

Further, according to the present embodiment, since the fuel tube 6 is cast into the branch pipe portion 3 of the intake manifold 1, it is completely possible that the fuel tube 6 may interfere with other parts and cause fuel leakage. Can be eliminated. Further, since the fuel tube 6 made of a pipe material is cast into the intake manifold 1, even if a cavity is formed in the intake manifold 1, fuel leakage does not occur.

In the above embodiment, the fuel tube 6 made of a pipe material such as an iron pipe is shown as being inserted into the intake manifold 1 made of an aluminum alloy casting, but the intake manifold made of an aluminum alloy casting or a synthetic resin is shown. At the time of forming the manifold, a portion functioning as a fuel tube may be integrally formed.

[0017]

According to the fuel injection system for an internal combustion engine of the present invention, the CPI system provided with the solenoid valve, the plurality of fuel tubes extending therefrom and the poppet valve at the tip of each fuel tube as described above. In the fuel injection device, the solenoid valve is mounted on the surge tank of the intake manifold integrated with the surge tank, the fuel tube is formed integrally with the branch pipe of the intake manifold, and the poppet valve is a mounting flange for the cylinder head of the intake manifold. It is possible to completely eliminate the possibility of fuel leakage due to interference of the fuel tube with other parts due to assembly variations, or to cause damage when installing the poppet valve, and to the intake manifold. By installing the solenoid valve and poppet valve in advance, The workability with can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of one embodiment of a fuel injection device for an internal combustion engine of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a perspective view of a conventional CPI fuel injection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Intake manifold 2 Surge tank part 3 Branch pipe part 4 Mounting flange 5 Solenoid valve 6 Fuel tube 7 Poppet valve

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02M 69/00 F02M 69/00 350P

Claims (1)

[Claims] A solenoid valve connected to a fuel pump and controlled to open and close at a predetermined timing to control fuel supply to a plurality of cylinders; a plurality of fuel tubes extending from the solenoid valve toward each cylinder; A poppet valve that is mounted at the tip of each fuel tube and injects fuel into each intake port of the cylinder head when the fuel pressure exceeds a predetermined value.The solenoid valve is a surge tank integrated with a surge tank. A fuel injection device for an internal combustion engine, wherein the fuel tube is formed integrally with a branch pipe portion of the intake manifold, and the poppet valve is mounted on a mounting flange for a cylinder head of the intake manifold.