JP2001221124A - Piping for fuel-return pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide piping for a fuel-return pipe from a fuel injection nozzle and a fuel filter without affection on an injection performance of the fuel injection nozzle by return of fuel from the fuel filter. SOLUTION: A first fuel-return pipe 1A is provided by making muitiple fuel injection nozzles N communicate in series, and a connector 7 communicated to a fuel tank by the piping is provided. The first fuel-return pipe 1A and a second fuel-return pipe 4 from the fuel filer 5 are separately laid to the connector 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel injection nozzle and a pipe for a fuel return pipe from a fuel filter.

[0002]

2. Description of the Related Art In a fuel injection nozzle, high-pressure fuel supplied from a fuel injection pump is injected into a combustion chamber from an injection port by opening a needle valve, but a part thereof leaks into a gap around the needle valve. , The needle valve is lubricated and returned to the fuel tank by a return pipe.

Conventionally, the pipe of this return pipe has been connected to the return of the fuel filter and communicated with the fuel tank. That is, in the example of the V-type 8-cylinder shown in FIG. 5, return pipes 1A and 1B in which nozzles N1 to N4 and N5 to N8 provided on left and right cylinder heads (not shown) are connected in series, respectively, are pipes 2E and 2F. Are connected to the fuel filter 5 and are connected to the fuel return pipe 4 from the filter 5 in an overlapping manner. The fuel return pipe 4 communicates with the connector 7 and is returned to a fuel tank (not shown).

FIG. 6 shows an example of six cylinders in series. A fuel return pipe 1E in which each of the nozzles N1 to N6 is connected in series is connected to an external pipe 2G from a symbol X to a filter. It is led to 5. And it is returned to the fuel tank via the connector 7 by the return pipe 4A from the filter 5.

In such a conventional pipe, when the return amount of the fuel filter 5 is large, the resistance of the pipe increases, and the return pipe 1A
Since the back pressure of the needle valve of the injection nozzle increases due to the increase in the pipe pressure in (1B), the fuel injection characteristics are affected, and this has been a problem when trying to improve the performance by detailed combustion control.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a fuel injection nozzle and a fuel return pipe from a fuel filter which do not affect the injection performance of the fuel injection nozzle due to the fuel return from the fuel filter. It is intended to provide.

[0007]

According to the present invention, in a pipe of a fuel return pipe from a fuel injection nozzle and a fuel filter, a first fuel return pipe is provided by connecting a plurality of fuel injection nozzles in series, A connector connected to the fuel tank by a pipe is provided, and the first fuel return pipe and the second fuel return pipe from the fuel filter are individually piped to the connector.

The first fuel return pipe may have a plurality of fuel injection nozzles, for example, divided into a plurality of groups for each cylinder head, and a first fuel return pipe may be provided for each group and merged. .

According to the present invention, since the first fuel return pipe from the fuel injection nozzle is provided separately from the fuel return pipe of the fuel filter, the first fuel return pipe on the nozzle side has an excess. Pressure does not occur. Therefore, the injection nozzle does not generate an abnormal back pressure, and stable and excellent injection performance can be obtained.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 and FIG. 2 show the V-type 8 of the present invention.
An embodiment in a cylinder engine is shown.
The embodiment will be described also with reference to FIG.

[0011] Fuel injection nozzles N1 to N4 and N5 to N8 (reference N
The first fuel return pipes 1A and 1B communicate with the respective nozzles in series at the fuel return port (representing a nozzle). Is connected to the connector 6 by the pipes 2A and 2B, and the pipe 3 is further integrated into the connector 7
Is communicated to.

On the other hand, the fuel return from the fuel filter 5
The second fuel return pipe 4 communicates with the connector 7, and the connector 7 communicates with the fuel tank through a pipe (not shown).

In this embodiment, the fuel injection nozzles N1 to N
The return of fuel from 4 goes through the return pipe 1A and the pipe 2A,
The return of the fuel from the fuel injection nozzles N5 to N8 is as follows.
Both are returned to the connector 6 via the return pipe 1B and the pipe 2B,
It is returned from the pipe 3 to the fuel tank via the connector 7. On the other hand, the return of the fuel from the fuel filter 5 is separately returned to the fuel tank via the connector 7 by the fuel return pipe 4.

Therefore, the fuel return pipe 1 of the fuel injection nozzle N is not affected by the return of the fuel from the filter 5, and no abnormal back pressure acts on the nozzle N. Injection performance is obtained.

FIG. 4 shows an embodiment of an in-line six-cylinder engine. The fuel injection nozzles N1 to N6 provided in the cylinder head have three groups of three (N1 to N1).
N3 and N4 to N6), and the nozzles are connected in series by fuel return pipes 1C and 1D, respectively. The fuel is returned from the fuel filter 5 to the connector 7 by the return pipe 4 in the same manner as in the above-described embodiment.

[0016]

According to the present invention, as described above, the fuel return pipe from the fuel injection nozzle and the fuel return pipe from the fuel filter are separated to prevent back pressure from being applied to the fuel injection nozzle. Good and stable injection performance can be obtained. This effect is particularly noticeable when high-pressure injection is adopted.
This is effective for performing detailed fuel injection control to improve engine output performance and exhaust gas properties.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a fuel return pipe according to the present invention.

FIG. 2 is a plan view clarifying a fuel return pipe system in the embodiment of FIG. 1;

FIG. 3 is a plan view showing a relationship between a piping system and an engine in the embodiment of FIGS. 1 and 2;

FIG. 4 is a plan view showing another embodiment of the present invention.

FIG. 5 is a plan view showing a fuel return pipe of a conventional V-type engine.

FIG. 6 is a plan view showing a fuel return pipe of a conventional in-line engine.

[Explanation of symbols]

 N1, N2, N3, ... fuel injection nozzles 1A, 1B, ... first fuel return pipe 2A, 2B, ... fuel pipe 4 ... second fuel return pipe 5, ...・ Fuel filter 6,7 ・ ・ ・ Connector

Claims (1)

[Claims] A first fuel return pipe provided in series with a plurality of fuel injection nozzles in a fuel return pipe from a fuel injection nozzle and a fuel filter, and a connector connected to the fuel tank by a pipe; Wherein the first fuel return pipe and the second fuel return pipe from the fuel filter are individually piped to their connectors, respectively.