JPH10252601A - Accumulator fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce assembling man-hours and pipe changing man-hours and eliminate a fear of leakage of fuel during change of a pipe. SOLUTION: The connection port 2 of a force feed pipe 1 extending from a supply pump is formed in the upper wall of a common rail 3. The same number of flow dampers 5 as that of injectors 4 are mounted on a common rail 3. Inflow ports for fuel formed in the respective injectors 4 are coupled to the respective corresponding outflow ports of the flow dampers 5 and by integrally holding the injector 4 at the common rail 3, the feed pressure of fuel to the injector is substantially increased and the man-hours in change of the pipe and the assembling man-hours are reduced, and a fear of outflow of fuel during the change of the pipe is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-accumulation type fuel injection device, and more particularly to a pressure-accumulation type fuel injection device excellent in assemblability and maintenance and inspection.

[0002]

2. Description of the Related Art As a conventional accumulator type fuel injection device, for example, there is one shown in FIG. In FIG. 3, fuel in a fuel tank A is sucked up by a feed pump C driven by a cam shaft of a supply pump B, sent to a fuel filter D and filtered, and then supplied to the supply pump B.
Sent to The fuel filter D is provided with an overflow valve E. When the pressure in the filter body becomes higher than a predetermined value, the valve E opens and returns to the fuel tank A via the overflow pipe F.

[0003] The fuel sent to the supply pump B is made high pressure and supplied to the common rail H via a pressure feed pipe G. The supply pump B is provided with a through feed valve I, and when the pressure in the pump body becomes higher than a set value, the valve I opens to return fuel to the fuel tank A.

The fuel sent to the common rail H is
It is sent to an injector K attached to each cylinder head via an injection pipe J, and is sprayed from a nozzle provided on the injector K as a spray into a combustion chamber. The fuel leaked from the injector K is returned to the fuel tank A by the leakage pipe L. M is a flow damper, N is a pressure limiter, and O is a through feed pipe.

[0005] In such a conventional accumulator type fuel injection device, the common rail H and the injector K are connected via the injection pipe J, respectively. Therefore, there is a need to assemble an injection pipe that functions only as a mere connecting means, so that the number of assembling steps of the injection device has been increased.

In addition, the actual fuel supply pressure of the injector K is reduced by the pressure loss due to the injection pipe J, and it is necessary to check for a fuel leak at the connection portion when the injection pipe J is replaced. In addition, since the pumping pipe G is conventionally connected to the bottom wall of the common rail H, there is a problem that the fuel in the common rail H flows out when the pumping pipe G is replaced, and a large number of man-hours are required for post-processing.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and reduces the number of assembling steps and the number of steps when replacing pipes, and avoids fuel leakage, etc., which is a concern when replacing pipes. It is an object of the present invention to provide a pressure-accumulation type fuel injection device that can perform the pressure accumulation.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a pressure-accumulation type fuel injection device in which fuel discharged from a supply pump is supplied via a common rail to injectors provided in each cylinder head. At
The connection port of the pressure feed pipe extending from the supply pump is formed on the upper wall of the common rail, and the same number of flow dampers as the number of injectors are mounted on the common rail. Then, by connecting the fuel inlet provided in each injector to the corresponding flow damper outlet,
It is characterized in that the injector is held integrally with the common rail.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic side view showing an embodiment of a pressure accumulating fuel injection device according to the present invention, and FIG. 2 is a front view of the common rail shown in FIG. 1 as viewed from a flow damper side.

[0010] In these figures, a connection port 2 of a pressure feed pipe 1 extending from a discharge port of a supply pump (not shown).
Are formed on the upper wall of the common rail 3, and the same number of flow dampers 5 as the number of injectors 4 attached to the cylinder head (not shown) are screwed and fixed to the side walls of the common rail 3 at the same pitch as the injectors 4.

Then, the retaining nuts 6 attached to the outlets of the flow dampers 5 are screwed into the outer peripheral thread portions of the connecting cylinders 7 forming the fuel inlets of the injectors 4 so that the injectors 4 are integrated with the common rail 3. I keep it. In addition, the flow damper 5 damps the pressure pulsation of the fuel in the common rail 3 and the injector 4 as in the related art, and at the same time, prevents an excessive amount of fuel from flowing to the injector 4. 8 is a leakage pipe, 9 is a pressure limiter, and 10 is a pressure sensor.

That is, in this embodiment, the flow damper 5 is mounted on the common rail 3 and the flow damper 5 is mounted on the common rail 3.
By directly connecting the injectors 4 to the
The injector 4 is integrally connected to the common rail 3 to eliminate the conventionally used injection pipe. Therefore, not only the man-hour for assembling the injection device, but also the replacement of the pipe is performed by the pumping pipe 1 extending from the supply pump.
Since only pipe replacement is required, it is possible to reduce the number of pipe replacement steps and the number of places to check for fuel leakage during pipe replacement.

Further, since the apparatus is a direct mounting type that does not use an injection pipe, there is no pressure loss due to the injection pipe. For this reason, even if a supply pump having the same specification as that of the related art is used, the fuel supply pressure to the injector 4 can be substantially increased.

Further, since the connection port 2 of the pressure feed pipe 1 extending from the supply pump is provided on the upper wall of the common rail 3, when the pressure feed pipe 1 is replaced, fuel in the common rail 3 leaks out. Not even.

In the above embodiment, the pressure limiter 9 is mounted on the end face of the common rail 3 and the pressure sensor 10 is mounted on the bottom wall of the common rail 3. However, the mounting positions are not limited to those in the embodiment. Alternatively, other sensors or the like can be attached as needed.

[0016]

As is apparent from the above description, according to the present invention, while the connection port of the pressure feed pipe extending from the supply pump is formed on the upper wall of the common rail, the same number of flow dampers as the number of injectors are mounted on the common rail. Since the fuel inlet provided in each injector is connected to the corresponding flow damper outlet and the injector is integrally held on the common rail, even if a supply pump with the same specifications as the conventional one is used, the injector is The fuel supply pressure to the fuel can be substantially increased, and
It is possible to reduce man-hours and assembling man-hours at the time of pipe replacement, and to avoid fuel outflow and the like, which have been concerned at the time of pipe replacement.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an embodiment of an accumulator type fuel injection device according to the present invention.

FIG. 2 is a front view of the common rail shown in FIG. 1 as viewed from a flow damper side.

FIG. 3 is a schematic configuration diagram illustrating an example of a conventional accumulator type fuel injection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure feed pipe 2 Connection port 3 Common rail 4 Injector 5 Flow damper 6 Retaining nut 7 Connection cylinder

Claims (1)

[Claims] In a pressure-accumulation type fuel injection device in which fuel discharged from a supply pump is supplied to an injector provided in each cylinder head via a common rail, a connection port of a pressure feed pipe extending from the supply pump is connected. Formed on the upper wall of the common rail, the same number of flow dampers as the number of injectors are mounted on the common rail, and the fuel inlets provided for each injector are connected to the corresponding flow damper outlets to hold the injectors integrally on the common rail. An accumulator-type fuel injection device, characterized in that: