JPH027253Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a rotary valve device for a pressure-increasing unit injector.

2 in Figures 1 and 3 is a rotary valve,
The lorry valve 2 has a spool 3 inside the valve body 12.
It is made by inserting. The valve body 12 is provided with a plurality of ports 5, and the spool 3 is provided with a fuel passage 6.
and a fuel supply port 4 communicating therewith. A metering pressure chamber 17 is formed between the end of the valve body 12 and the end of the spool 3.

The metering pressure chamber 17 is connected to a tank (not shown) via a pipe line 18.
A metering valve (pressure reducing valve) 8 is provided.

A metering groove 10 consisting of a notch is formed in the circumferential portion of the spool 3, and this metering groove 10 is used to switch between an injection area and a metering area (an area that determines the amount of injection).

The metering groove 10 communicates the port 5 in the metering area with the metering pressure chamber 17.

Each port 5 of the rotary valve 2 is connected to a cylinder chamber 33 of the pressure increasing unit injector 1 via an injection pipe 7, respectively.

The injector 1 includes a pressure increasing piston 27, a check valve 28, a suction return valve 29, a needle valve 30, and the like. The pressure increasing piston 27 increases the pressure of the fuel supplied from the rotary valve 2 and controls the injection amount. The pressure increasing piston 27 is connected to the piston plunger 3 by the return spring 31.
2 and is pressed (compressed) toward the cylinder chamber 33 side. The pressure increase ratio of the pressure increase piston is determined by the area ratio of the piston 27 and the plunger 32. The volume of the chamber 34 is determined by the position where the back pressure of the pressure increasing piston 27 (pressure on the cylinder chamber 33 side) and the compression force (pressing force) of the return spring 31 reach equilibrium, and the injection amount is determined. That is, when the back pressure is increased, the piston plunger 32 moves downward, the volume of the chamber 34 becomes smaller, and the injection amount decreases. Conversely, when the back pressure is lowered, the piston plunger 32 moves upward, increasing the volume of the chamber 34 and increasing the injection amount. In this way, the injection amount is regulated.

As shown in the figure, a passage 35 is formed in the piston plunger 32 that communicates between the end face 32a and the side surface, and when the end face comes into contact with the bottom face of the chamber 34, a passage 35 is formed that communicates with the end face 32a and the side face. The suction valve 29 is connected to the suction valve 29 .

A fuel supply port 4 opens on the outer peripheral surface of the spool 3 as the spool 3 of the rotary valve 2 rotates.
are sequentially connected to the ports 5 of the rotary valves 2 connected to the pressure increasing unit injectors 1 of each cylinder to supply fuel from the fuel passages 6 of the spools 3.

When the fuel supply port 4 communicates with one port 5 as the spool 3 rotates, the fuel passage 6
High-pressure fuel is sent to the cylinder chamber 33 via the fuel supply port 4 and the injection pipe 7, while the other port 5 in the metering area is sent to the metering pressure chamber 17 via the metering groove 10. The pressure in this metering pressure chamber 17 is controlled by a metering valve 18, and the pressure in this metering pressure chamber 17 is controlled by a metering valve 18 to communicate with the cylinder chamber 33 of the pressure boosting unit injector 1 in the metering area.
The pressure is controlled, and this pressure is balanced with the spring force of the return spring 31 to determine the injection amount.

However, in rotary valve devices, the second
As shown in FIG.
The injectors 1 of the book interfere with each other during metering, and disturbances generated in any one of the injectors 1 affect the other injectors 1, impairing the stability of metering.

The present invention was developed in view of the above circumstances, and its purpose is to provide a rotary valve device for a pressure-increasing unit injector that can ensure stability in metering without the injectors interfering with each other during metering. It is about providing.

Hereinafter, the present invention will be explained based on FIG. 5 and subsequent figures. FIG. 5 shows the rotary valve 2. In this rotary valve 2, parts that are the same as those in the conventional rotary valve 2 shown in FIG. 3 are designated by the same reference numerals.

That is, 3 is a spool, 4 is a fuel supply port, 5 is a port, 6 is a fuel passage, 7 is an injection pipe, 8
1 is a metering valve, 17 is a metering pressure chamber, and 18 is a conduit.

A plurality of metering grooves 20 are formed on the periphery of the spool 3 independently at intervals in the circumferential direction, and each metering groove 20 is bored in the axial direction of the spool 3 to form an end surface. The metering pressure chambers 17 are connected to each other through communication holes 22 that are open to the metering pressure chambers 17, respectively.

However, since the metering groove 20 is divided into a plurality of parts and at the same time the fuel returned from the injector 1 is prevented from overlapping in the metering groove 20, even if there is interference, the metering pressure chamber 17 has a large capacity. Since the injector 1 is operated via the injector 1, a disturbance occurring in one of the injectors 1 will not affect the other injectors.

As detailed above, in the present invention, since the metering groove 20 formed on the circumference of the spool 3 is divided into a plurality of parts, each injector does not interfere with each other during metering, and disturbances caused by any one of the injectors can be avoided. This eliminates the possibility of affecting other injectors and impairing metering stability.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams of the configuration of a conventional rotary valve and pressure boosting unit injector, Figure 3 is an explanatory diagram of a conventional rotary valve device, Figure 4 is an exploded view of the spool, and Figure 5 is an explanatory diagram of the configuration of a conventional rotary valve and a pressure boosting unit injector. FIG. 6 is a longitudinal sectional view of a main part of the rotary valve device according to the present invention, FIG. 6 is a partially sectional side view of the spool, and FIG. 7 is a developed view of the spool. 2 is a rotary valve, 3 is a spool, 17 is a metering pressure chamber, and 20 is a metering groove.

Claims (1)

[Scope of utility model registration request] Metering groove 2 formed around the spool 3
A rotary valve device of a pressure-increasing unit injector, characterized in that 0 is divided into a plurality of parts.