JPH0434031B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a distribution valve with an oil shutoff function.

Mainly in large marine diesel engines,
A plurality of fuel injection valves may be provided in one cylinder.

An example of the fuel injection system of a diesel engine in which three fuel injection valves are arranged in one cylinder is shown in Fig. 1. In the figure, 1 is the fuel pump, and 2 is the fuel oil supplied from the fuel pump 1. Distribution valves 3a, 3b, and 3c are attached to one cylinder 4, and 5 is a fuel injection valve that injects fuel oil distributed and fed by the distribution valve 2 into the cylinder 4. A high pressure pipe connecting the fuel pump 1 and the distribution valve 2, 6a,
6b, 6c are the distribution valve 2 and the fuel injection valves 3a, 3b,
This is a high pressure pipe that connects 3c.

In the fuel injection system of a diesel engine having such a configuration, fuel oil discharged from the fuel pump 1 passes through the high pressure pipe 5, is introduced into the distribution valve 2, is distributed in three directions by the distribution valve 2, and is then transferred to the high pressure pipe. 6a, 6b,
The fuel is introduced into the fuel injection valves 3a, 3b, 3c through the fuel injection valve 6c, and is injected into the cylinder 4 from each fuel injection valve 3a, 3b, 3c to be combusted.

However, in the above fuel injection system which is not a pressure accumulation type, the plunger diameter of the fuel pump 1, the fuel injection valve 3a,
The specifications of the fuel injection system, such as the nozzle area of 3b and 3c, are fixed and cannot be changed during operation, so the injection pressure of the fuel oil injected from the nozzles of fuel injection valves 3a, 3b, and 3c increases as the load increases. However, the lower the load operation, the worse the atomization state of the fuel oil injected into the cylinder 4, leading to problems such as poor combustion and black smoke generation. It was hot.

Therefore, in order to solve the above problem, marine diesel engines have spare fuel injection valves for low-load use, and during long-term low-load operation, all fuel injection valves are replaced with low-load use while the engine is stopped. However, replacing the fuel injector has the disadvantage that the work is complicated and time consuming.

The present invention eliminates the need to replace the fuel injector with a low-load one even during low-load operation, and also eliminates problems such as fuel failure and black smoke generation, thereby improving the performance of diesel engines during low-load operation. This was done with the aim of improving.

The present invention provides a distribution valve capable of supplying fuel to a plurality of fuel injection valves attached to an engine, in which a distribution shaft is rotatably fitted inside the distribution valve main body, and oil is distributed to the distribution shaft. A main flow hole for feeding into the shaft is provided toward the axial direction of the distribution shaft, and the distribution shaft has three or more distribution holes that communicate with the main flow hole and extend in a direction perpendicular to the main flow hole. are provided at the required intervals in the circumferential direction, and on the outer periphery of the distribution shaft,
A flow path that communicates each distribution hole is provided over an area narrower than the entire circumference of the distribution shaft, and the distribution valve body has distribution holes that are the same in number as the distribution holes provided in the distribution shaft and that can communicate with the distribution holes. are provided at substantially the same intervals in the circumferential direction as the distribution holes provided on the distribution shaft, and configured so that required distribution holes among the distribution holes on the distribution valve body side can be blocked by the outer periphery of the distribution shaft as necessary. Even when the distribution shaft is at a mid-rotation position and the distribution hole provided in the distribution shaft is not in a position facing the distribution hole provided in the distribution valve body, the valve communicates with the flow path from the distribution hole provided in the distribution shaft. It is constructed so that oil can be supplied to distribution holes provided in the main body. Therefore, if necessary, at least one of the distribution holes inside the valve body can be shut off by switching the distribution shaft;
Also, even during rotation for switching the distribution shaft, the distribution holes other than those to be shut off in the distribution valve body are
Oil can be sent through the main flow hole.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 2 to 5 and FIGS. 6A, 6B, and 6C show an embodiment of the distribution valve of the present invention, and the distribution valve 2 has a shutoff mechanism for the fuel injection valves 3a, 3b, and 3c shown in FIG. It is equipped with That is, the planar shape of the distribution valve body 7 is square, and the distribution valve body 7 is provided with a cylindrical hollow portion 8, so that the distribution valve body 7 can be rotated manually or by an automatic switching device. The distribution shaft 9 is fitted onto the top cover 10 on the top of the distribution valve body 7.
and a lower cover 11 are attached to the lower part of the distribution valve main body 7 with mounting bolts 12, respectively. The upper end of the distribution shaft 9 passes through the upper cover 10 and projects upwardly, to which an automatic switching device can be connected if necessary.

A fuel oil main flow hole 13 is formed in the axis of the distribution shaft 9, and extends to a midway point in the longitudinal direction of the distribution shaft 9, and a protrusion 14 of a predetermined length that protrudes upward from the lower cover 11 is provided in the distribution shaft 9. The lower cover 11 and the protrusion 14 of the lower cover 11 are fitted into the fuel oil main flow hole 13 of the shaft 9.
A fuel oil main flow hole 15 communicating with the fuel oil main flow hole 13 is bored concentrically with the fuel oil main flow hole 13, and a high pressure pipe 5 shown in FIG. Install the main nipple 16 for connecting.

The distribution shaft 9 has three fuel oil distribution holes 17a, 17 extending in a direction perpendicular to the axis of the distribution shaft 9.
b, 17c are drilled so that one end side opens on the outer periphery of the distribution shaft 9 and the other end side communicates with the fuel oil main distribution hole 13.
Grooves 18 and 1 that connect 7b, 17b and 17c
9 is provided facing in the circumferential direction, and a slit 21 is provided at a predetermined position on the outer circumference of the distribution shaft 9 and is substantially parallel to the axis of the distribution shaft 9 and communicates with the fuel oil main flow hole 13 through the fuel oil distribution hole. 21 to the distribution valve body 7
a hollow part 8' surrounded by a distribution shaft 9 and a top cover 10;
to open.

The distribution valve body 7 is provided with fuel oil distribution holes 20a, 20b, 20c that can communicate with the fuel oil distribution holes 17a, 17b, 17c provided in the distribution shaft 9, and the fuel oil distribution holes 20a, 20b, 20c are provided. The tip of the fuel oil distribution hole 2 is opened on the outer surface of the distribution valve body 7.
Branch pipe nipples 22a, 22b, 22c to which the high pressure pipes 6a, 6b, 6c of FIG. 1 can be connected are attached to the outer open ends of the pipes 0a, 20b, 20c. The fuel oil distribution holes are 17a, 17b, 17
b and 17c, 20a and 20b, and 20b and 20c are arranged at intervals of approximately 90 degrees, and during high load operation, 1
7a and 20a, 17b and 20b, 17c and 20c
17b and 20a, and 17c and 20b are arranged in a straight line during low load operation (see FIGS. 6A and 6C).

In the figure, reference numeral 23 indicates a leakage oil release hole provided in the protruding portion 24 of the upper lid 10 to release leaked oil from the hollow portion 8' to the outside, and 25 indicates a leakage oil release hole provided above the protruding portion 24 on the upper portion of the upper lid 10 of the distribution shaft 9. 26 is a mounting nut screwed onto the portion of the distribution shaft 9 above the stabilizing plate 25; 27 is the stabilizing plate 25 and the upper lid 10; The clamp 28 provided between the fuel oil main flow hole 13 and the fuel oil main flow hole 28 is a leakage oil hole provided at the bottom of the distribution valve body 7 for discharging leakage oil from the fuel oil main flow hole 13 to the outside.

Next, the operation of the present invention will be explained.

Fuel oil compressed and sent by the fuel pump 1 shown in FIG. 1 is supplied from the main nipple 16 to the fuel oil main flow hole 13 through the fuel oil main flow hole 15. In case of high load operation, the fuel oil distribution holes 17a, 20a, 17
b and 20b, and 17c and 20c are communicated with each other, so that fuel oil flows through each fuel oil distribution hole 17.
a, 17b, 17c to 20a, 20b, 20c
The fuel is sent from branch pipe nipples 22a, 22b, 22c to each fuel injection valve 3a, 3b, 3c via high pressure pipes 6a, 6b, 6c shown in FIG. is injected into.

When the load is low, the distribution shaft 9 is sequentially rotated manually or automatically, and the fuel oil distribution hole 20c is rotated approximately 90 degrees through the state shown in Fig. 6B to the state shown in Fig. 6C.
and close the fuel oil distribution holes 17b, 20a, 17.
c and 20b are communicated. Therefore, the fuel oil introduced into the fuel oil main flow hole 13 is transferred to the fuel oil distribution hole 1.
The fuel oil is sent to the fuel injection valve 3a through the fuel injection valves 7b and 20a, and is also sent to the fuel injection valve 3b through the fuel oil distribution holes 17c and 20b, and is injected into the cylinder 4 from the fuel injection valves 3a and 3b. Therefore, only one fuel injection valve 3c is cut off from fuel injection.

As shown in FIG.
3 through each fuel oil distribution hole 17a, 17b, 17
c, and the fuel oil that entered the fuel oil distribution hole 17a is introduced into the fuel oil distribution hole 20a through the groove 18, and a part of the fuel oil that entered the fuel oil distribution hole 17b flows from the groove 18 into the fuel oil distribution hole 20a. 20a. Further, the fuel oil that has entered the fuel oil distribution hole 17c is introduced into the fuel oil distribution hole 20b via the groove 19, and a part of the fuel oil that has entered the fuel oil distribution hole 17b is introduced from the groove 19 into the fuel oil distribution hole 20b. Ru. Therefore, even while the distribution shaft 9 is rotating, only one fuel injection valve 3c is cut off from fuel injection, and the supply of fuel oil to the other fuel injection valves 3a and 3b is not cut off.

As mentioned above, by shutting off one fuel injector during low load operation, the total nozzle area of the fuel injector nozzle is reduced to 2/3, so the fuel oil injection pressure increases and it is not shut off. The atomization state of the fuel oil injected from the fuel injection valve is improved, the combustion state is improved, the fuel efficiency is lowered, and smoke generation is also reduced.

The injection pressure waveform when one fuel injection valve is shut off is shown by a dotted line in FIG. 8A. The waveforms shown by the solid line in FIG. 8A show the conventional case in which not a single fuel injection valve can be shut off, and it can be seen from these waveforms that when the fuel injection valves are shut off, the injection pressure increases. In addition, the needle valve lift amount of the fuel injection valve nozzle is shown in Figure 8B, where the dotted line shows the case when one fuel injection valve is shut off, and the solid line shows the conventional case where no fuel injection valve can be shut off. .

When the fuel oil sent from the fuel pump 1 is under high pressure, the airtightness of the sliding portion of the distribution shaft 9 and the operating state of the distribution shaft 9 become a problem. However, in the case of this embodiment, the distribution shaft 9, the distribution valve body 7, and the upper and lower lids 10, 1
Since the length of the sliding portion with respect to 1 is made long and the gap between the sliding portion is made small, airtightness is maintained well.
In addition, by making the cross-sectional area of the ceiling part X of the fuel oil main flow hole 13 equal to the area of the stepped part of the distribution shaft 9 facing the hollow part 8', the force acting upward on the distribution shaft 9 can be canceled. Moreover, since the oil leaking to the lower surface of the distribution shaft 9 is discharged to the outside from the leakage oil relief hole 28, it does not accumulate on the lower surface of the distribution shaft 9. Therefore, since the distribution shaft 9 is not pushed upward, the stepped portion of the distribution shaft 9 is not pressed against the lower surface of the upper lid 10, and the distribution shaft 9 can be rotated with a slight force.

FIG. 7 shows another embodiment of the present invention, in which the distribution valve body 7
is a regular hexagon, and the distribution shaft 9 has four fuel oil distribution holes 17a, 17b, 17c, and 17d,
The fuel oil distribution holes provided in the distribution valve body 7 are
There are four grooves 0b, 20c, and 20d, and a groove 29 connecting the fuel oil distribution holes 17c and 17d is installed on the distribution shaft 9.
This is an example where it is provided on the outer periphery of the Fuel oil distribution hole 17a,
20a and 17b, 20b, 17b, 20b and 17
The spacing between c, 20c, 17c, 20c and 17d, 20d is approximately 60 degrees. With this configuration, the two fuel oil distribution holes 20d and 20c can be closed by rotating the distribution shaft 9 approximately 90 degrees clockwise from the state shown in FIG. In the drawings, the same reference numerals as those shown in FIG. 2, etc. indicate the same components.

The distribution valve of the present invention can be implemented arbitrarily as long as there are a plurality of fuel injectors and one or more fuel injectors are to be shut off. In the case of main shutoff, it is preferable that the planar shape of the distribution valve body 7 is a regular n+j square, and the number of fuel oil distribution holes is also n sets, and the interval between them is
It may be 360/(n+j) degrees. That is, in the embodiments shown in FIGS. 2 to 5 and 6 A to C, the number of fuel injectors is three and the number of fuel injectors to be shut off is one, so the planar shape of the distribution valve body is is square, and the fuel oil distribution holes are spaced at 90 degrees. In the embodiment shown in FIG. 8, the number of fuel injection valves is 4.
Since the number of fuel injection valves to be shut off individually is two at most, the planar shape of the distribution valve body is a regular hexagon, and the interval between the fuel oil distribution holes is 60 degrees.

In addition, in the embodiments of the present invention, the case where the planar shape of the distribution valve body is made into a regular polygon has been described, but as long as the distribution holes are arranged at predetermined intervals in the circumferential direction, the planar shape may not be made into a regular polygon. It can be circular or any other shape, and instead of the groove provided on the outer periphery of the distribution shaft, a communication hole may be provided inside the distribution shaft.In short, it is sufficient to provide a flow path that communicates each distribution hole of the distribution shaft. Of course, various other changes may be made without departing from the spirit of the present invention.

According to the distribution valve of the present invention, () the fuel injection state and engine performance during high-load operation are not impaired at all, and the combustion state is improved by reducing fuel consumption, smoke generation, and combustion chamber fouling during low-load operation; Improvements are possible.

() Since switching can be performed during operation and there is no need to stop the engine, optimal control of the fuel injection system can be performed by performing automatic operation using engine load, etc. as an input signal. Since fuel injection valves for low loads are not required,
Work efficiency is improved because there is no need to replace the fuel injector in response to the engine load. Since oil can be sent to distribution holes in the valve body other than the distribution holes that should be shut off, various excellent effects can be achieved, such as no hindrance to operation.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the fuel injection system of a diesel engine, Fig. 2 is a longitudinal cross-sectional view of an embodiment of the distribution valve of the present invention, Fig. 3 is a view taken in the - direction arrow of Fig. 2, and Fig. 4 is a diagram illustrating the fuel injection system of a diesel engine. FIG. 2 is a plan view, FIG. 5 is an explanatory diagram of the distribution shaft used in the distribution valve of FIG. 2, and FIG. 6 A, B, and C are explanatory diagrams of the operating states of the distribution valve of the present invention. A is an explanatory diagram of the state during high load operation, Figure 6 B is an explanatory diagram of the state in the middle of switching from high load operation to low load operation,
Fig. 6C is an explanatory diagram of the state during low load operation, Fig. 7 is an explanatory diagram of another embodiment of the distribution valve of the present invention, and Fig. 8A is an explanatory diagram of the relationship between the injection pressure of the fuel injection valve and time. The graph shown in FIG. 8B is a graph showing the relationship between the needle valve lift amount of the fuel injection valve and time. In the figure, 2 is a distribution valve, 7 is a distribution valve body, 9 is a distribution shaft, 13 is a fuel oil main distribution hole, 15 is a fuel oil main distribution hole, 17a, 17b, 17c, 17d are fuel oil distribution holes, 18, 19 are grooves, 20a, 20b, 20
c and 20d are fuel oil distribution holes, and 29 is a groove.

Claims (1)

[Claims] 1. In a distribution valve capable of supplying fuel to a plurality of fuel injection valves attached to an engine, a distribution shaft is rotatably fitted inside the distribution valve body, and oil is directed into the distribution shaft. A main flow hole for feeding is provided in the axial direction of the distribution shaft, and the distribution shaft is provided with three or more distribution holes that communicate with the main flow hole and extend in a direction perpendicular to the main flow hole. A distribution passage provided on the distribution shaft at a required interval in the distribution valve body and a distribution passage provided on the distribution shaft in a range narrower than the entire circumference of the distribution shaft is provided on the outer periphery of the distribution shaft to communicate each distribution hole. Distribution holes of the same number as the holes and capable of communicating with the distribution holes are provided at approximately the same intervals in the circumferential direction as the distribution holes provided on the distribution shaft, and if necessary, the required number of distribution holes of the distribution valve body side are provided. The distribution hole is configured to be blocked by the outer periphery of the distribution shaft, and even when the distribution shaft is at a mid-rotation position and the distribution hole provided in the distribution shaft is not in a position facing the distribution hole provided in the distribution valve body, the distribution A distribution valve characterized in that oil can be supplied from a distribution hole provided in a shaft to a distribution hole provided in a valve body that communicates with the flow path.