JPH0114757Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary valve for a fuel supply device that sequentially supplies fuel to the chambers of a plurality of injection valves and sequentially connects the chambers of each injection valve to a drain.

As shown in FIG. 1, the applicant first sequentially supplied high-pressure fuel to chambers a of a plurality of pressure-increasing unit injectors A using rotary valves B, and connected each chamber a to a drain using rotary valve B. The application has been filed for a fuel supply system in which fuel is sequentially injected from each pressure boosting unit injector A that is connected in sequence.

As shown in FIGS. 1 and 2, this rotary valve B has a plurality of ports C ₁ ,
_C6 , a fuel supply port e is formed at the axis of the spool d, and the fuel supply port e is sequentially connected to each port _C1 to _C6 by an outlet port f, and the valve body A drain port g that opens to chamber i is formed in b, an arcuate drain groove h is formed in the peripheral wall of spool d, a hole j is formed that opens the arcuate groove h to chamber i, and an outlet port f is formed. One of the ports C ₁ to C ₆ is sequentially opened to sequentially supply high-pressure fuel to the chamber a, and the other port C ₁ to _{C 6} is opened to the drain groove h and connected to the drain from the drain port g. The high-pressure fuel in chamber a is discharged to the drain.

However, with this rotary valve structure, the spool d is pushed to the opposite side by the reaction of the high fuel pressure at the outlet port f, and the sliding resistance between the inner wall b' of the valve body b and the spool d is large. This causes problems such as the spool d becoming unable to rotate smoothly.

Therefore, it is conceivable to form a pressure balance port on the side opposite to the outlet port f of the spool d, but since the drain groove h is formed on the opposite side, the above-mentioned port cannot be formed.

The present invention was devised in view of the above circumstances, and its purpose is to provide a rotary valve for a fuel supply device in which the spool does not come into strong pressure contact with the inner wall of the valve body, and the spool can rotate smoothly. That's true.

Embodiments of the present invention will be described below with reference to FIG. 3 and subsequent figures.

A discharge passage 1a of the fuel pump 1 is connected to a pressure accumulator 2 and a rotary valve 3.

The rotary valve 3 has a hole 4 in a valve body 4.
A spool 5 is rotatably inserted into the inside of the spool 5, and the spool 5 is connected to a crankshaft of an engine (not shown) so as to be driven to rotate synchronously.

The valve body 4 has an inlet port 6 and a first
~Sixth outlet ports 7 ₁ to 7 ₆ are formed, and each outlet port 7 is connected to an injection valve 8, respectively.

The spool 5 is formed with an annular groove 16 opening to the inlet port 6, and a blind hole 17 is bored in the axial center. Inlet passages 18 ₁ and 18 ₃ are bored, and the spool 5 has an outlet port 19 and an arcuate drain groove 20 opened to the outlet port 7. On the opposite side, a pair of pressure balance ports 21, 21 are formed so as to be located on both sides of the drain groove 20, and the sum of the cross-sectional areas of the pair of ports 21, 21 is the same as the cross-sectional area of the outlet port 19. It's summery.

A suction valve 22 is provided in the blind hole 17.

The suction valve 22 has a tapered valve seat 2 in the blind hole 17.
3, a tapered contact surface 24 is pressed by a spring 25, and the suction and return valve 22 is pushed against the spring 25 to flow from the inlet port 6 side to the port 7 side, and It is arranged so that it does not flow from the to the inlet port 6 side.

A hole 27 opening into a metering chamber 26 is bored in the drain groove 20, and the metering chamber 26 communicates with a tank 29 through a variable throttle 28, and the variable throttle 28 is controlled to change its throttle value by a rotary solenoid 30. Ru.

In the injection valve 8, the injection hole 32 of the valve body 31 can be opened and closed by a needle valve 33, the needle valve 33 is set to a closed position by a spring 34, and is set to an open position by pressure acting on a step portion 33a. The space 35 opened at 33a is opened and communicated with the chamber 37 through a passage 36, and a piston 39 is inserted into the cylinder hole 38 of the valve body 31 to form an upper chamber 40 and a lower chamber 41, and the upper chamber 40 is connected to the inlet. 42 and a passage 43, the passage 43 is communicated with the chamber 37 via a check valve 44, and the lower chamber 41 is connected to the tank 29.
The lower chamber 41 and the chamber 37 are connected to each other by a passage 46 of a movable rod 45, and the movable rod 45 is held in contact with the piston 39 by a spring 47. 4
8 is a check valve.

Next, the operation will be explained.

In the illustrated state, the fuel discharged from the fuel pump 1 is supplied to the inlet port 6 after pulsation is absorbed by the pressure accumulator 2.

The fuel flowing into the inlet port 6 flows through the annular groove 16→
Inlet hole 18 → Blind hole 17 → Outlet port 19 → First port 7 ₁ → Inlet 42 and flows into upper chamber 4 of injection valve 8
0.

The fuel supplied to the upper chamber 40 is supplied to the passage 43 → check valve 44 → chamber 37 → passage 36 → space 35.

Subsequently, the fuel that entered the upper chamber 40 is transferred to the piston 39.
is pushed down to increase the pressure in the space 35 through the passage 36, and the needle valve 33 is pushed up against the spring force pressing the needle valve 33 to inject fuel from the nozzle hole 32.

Furthermore, by pushing down the piston 39, the movable rod 45
The chamber 37 and the lower chamber 41 are communicated with each other via the passage 46 and the check valve 48, and the pressure inside the chamber 37 is lowered to end the fuel injection.

At this time, high pressure acts on the outlet port 19 and ports 21, 21 in the spool 5, but the pressures are balanced and the spool 5 is not pressed against the hole 4a of the valve body 4.

Even after fuel injection is completed, high pressure remains in the communication path between the first port ₇₁ and the inlet 42 of the injection valve 8, but the suction valve 22 returns to the closed position by the spring 25, so The volume of the blind hole 17 increases accordingly,
The high pressure mentioned above is relieved.

After this, the spool 5 rotates and the first port 7
₁ opens into the drain groove 20, and the fuel in the upper chamber 40 flows into the metering chamber 26 through the hole 27 and flows out into the tank 29 through the variable throttle 28, so that the residual pressure in the upper chamber 40 is variable. The throttle value of the throttle 28 determines, and the upward return position of the piston 39 is determined by the residual pressure in the upper chamber 40.

Therefore, by changing the aperture value of the variable throttle 28, the upward return position of the piston 39 can be changed, thereby controlling the amount of injected fuel to be increased or decreased the next time fuel is supplied.

In other words, the amount of injected fuel is determined by the downward stroke of the movable rod 45 until it communicates the passage 46 with the lower chamber 41, and the amount of fuel injected is determined by the downward stroke of the movable rod 45 until it communicates the passage 46 with the lower chamber 41. ), the stroke becomes longer; if the residual pressure is lowered (residual pressure is high), the stroke becomes shorter; therefore, by changing the residual pressure, the next fuel injection amount can be controlled to increase or decrease.

In addition, since the high pressure at the end of fuel injection is relieved by the action of the suction valve 22, the fuel is supplied into the metering chamber 26, so that pressure fluctuations do not occur in the metering chamber 26, and the aforementioned fuel Increase/decrease control of injection amount can be performed with high precision.

The present invention is as described above, and by rotating the spool 5, fuel flowing in from the inlet port 11 can be sequentially supplied to the ports and to the chambers of each injector, and the remaining ports can be connected to the drain groove 20 and the hole. 27
Since the fuel can be communicated with the drain side, the fuel in the chamber of the injector to which fuel is not being supplied can be discharged to the drain side.

Therefore, fuel can be reliably injected sequentially from the plurality of injection valves.

Further, an arcuate drain groove 20 is formed at a position facing the outlet port 19 of the spool 5, and this drain groove 20 communicates with the drain side through a hole 27 opened in the end surface of the spool 5. The outer circumferential surface on the side opposite to the outlet port 19 has a large area other than the drain groove 20, and is connected to the hole 4 of the valve body 4.
a, so even if the spool 5 is pressed to the opposite side by the high pressure fuel at the outlet port 19, it will be pressed against the hole 4a of the valve body 4 over a wide area,
A load is not partially applied to the hole 4a, that is, the inner wall of the valve body 4, and the surface pressure does not increase, and there is a pair of pressure points across the blind hole 17 and the outer peripheral surface on the opposite side of the outlet port 19 in the spool 5. Since the ports 21, 21 for balance are formed on both sides of the drain groove 20, the downward force of the spool 5 due to the high pressure fuel acting on the outlet port 19 is transmitted through the pair of ports 21, 21 for pressure balance. The spool 5 can be rotated smoothly without being strongly pressed into contact with the inner wall of the valve body 4 by balancing the pushing up force of the high-pressure fuel acting between the outer circumferential surface of the spool 5 and the inner wall of the valve body 4.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the previously applied device, Fig. 2 is a partial sectional view of the rotary valve, Fig. 3 is an overall explanatory diagram showing an embodiment of the present invention, and Figs.
It is a - line, - line sectional view of a figure. 4 is the valve body, 4a is the hole, 5 is the spool,
7 ₁ to 7 ₆ are ports, 19 is an outlet port, 20 is a drain groove, and 21 is a port for pressure balance.

Claims (1)

[Scope of utility model registration request] The spool 5 is rotatably fitted into the hole 4a of the valve body 4, and an inlet port 11 that opens to the hole 4a is formed in the valve body 4, and a plurality of ports that open to the hole 4a are formed radially, and the axis of the spool 5 A blind hole 17 is bored in the core, a passage is formed through the blind hole 17 to the inlet port 11, and the blind hole 17 is formed in a position facing the plurality of ports in the spool 5. A radial outlet port 19 that opens to the port and an arcuate drain groove 20 that opens to the remaining ports are formed, and a hole 27 is formed between the drain groove 20 and the end face of the spool 5 to form the drain groove. 20 is connected to the drain side through a hole 27, and a pair of ports 21, 21 for pressure balance extending between the blind hole 17 and the outer peripheral surface on the opposite side of the outlet port 19 of the spool 5 are provided on both sides of the drain groove 20. A rotary valve for a fuel supply device, characterized in that the ports are respectively formed and communicated with the chambers of a pressure-increasing injection valve 15.