JPS59115440A - Fuel injector for multicylinder internal-combustion engine - Google Patents

Abstract

PURPOSE:To reduce the influence of injection pulsation between injectors each other in each accumulator by dividing injectors into a plurality of groups into the injectors having the injection order departed each other are set into one group and installing an accumulator in close to each group. CONSTITUTION:The injectors 1a-1f installed in the respective cylinders are set in the injection order of 1 5 3 6 2 4. An accumulator 204 on one high- pressure side is installed in close to the injectors 1a-1c having the injection order departed each other in one group, and connected through the respective pipings 21a-21c. An accumulator 205 on the other high-pressure side is connected to the injectors having the injection order departed each other in the other group. Thus, the influence of injection pulsation between injectors each other can be reduced in each accumulator.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection device that injects fuel into each cylinder from a common fuel supply source using an injector provided for each cylinder.

In a fuel injection system that injects fuel from a common fuel supply source to each cylinder through its own injector, if the pressure of the common fuel supply source is not stable, the injection characteristics between the cylinders will vary. There is a problem that causes In order to stabilize the pressure on the fuel supply source side and ensure uniform and highly accurate injection characteristics between cylinders, conventionally a common accumulator was installed at the fuel supply source, and this accumulator was connected to each injector using piping. measures were adopted. However, this structure requires a large number of piping connections between the accumulator and each injector, and the distance is long, resulting in a complicated piping structure.)
However, since the accumulator is common, pulsating pressure is generated due to the influence of other cylinders, which tends to cause pulsation. In order to eliminate the influence of the pulsating pressure of other cylinders, it may be possible to increase the size of the accumulator, but this has the drawback of increasing the size of the entire injection device.

On the other hand, it is also possible to install an accumulator just before each injector and connect these accumulators to the fuel supply source, but this also requires a large number of pipes and a long distance between each accumulator and the fuel supply source, so the piping structure is difficult. In addition to the complexity, an accumulator is required for each injector, resulting in disadvantages such as an increase in the number of parts and a large installation space.

The present invention was developed based on these circumstances, and it simplifies the piping structure, reduces the number of accumulators used, eliminates pulsation caused by the influence of other cylinders, and provides fuel at equal pressure to each injector. The object of the present invention is to provide a fuel injection device for a multi-cylinder internal combustion engine that can supply fuel to a multi-cylinder internal combustion engine.

That is, the present invention divides each injector into a plurality of groups, each grouping the injectors with different injection orders.
With a single accumulator for each of these groups,
The fuel sent from the fuel supply source is distributed to the injectors of the group by this accumulator, and the number of piping from the fuel supply source to the accumulator can be reduced, and the number of accumulators used is only the number of groups. Since fuel is supplied to injectors whose injection order is different from each other, pulsation is reduced even if the injector is small.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

In FIG. 1, number 100 is, for example, a six-cylinder engine. 1a to 1f are injectors provided for each cylinder, and the injection order (explosion order) is set in the order of ■→■→■→■→■→■. 2 is a high pressure fuel supply source, and 3 is a low pressure fuel supply source. The high pressure fuel supply source 2 is a pipe 21x.

21y to the high pressure side accumulator 204.
205. One high-pressure side accumulator 204 is arranged close to one group of injectors 1 a + 1 b + 1 e which are separated from each other in the injection order, and are connected to pipes 21 a 121 b, respectively.

21c, and the other high pressure side accumulator 205 is close to injectors ld, Ie, and If of other groups whose injection order is distant from each other, and the other high pressure side accumulator 205 is connected via piping 21c.
d, 21e, and 21f. The low pressure fuel supply source 3 is connected to low pressure side accumulators 304 and 305 via pipes 15x and 15y, respectively.

゛ One low-pressure side accumulator 304 is provided close to the injectors 1h, 1b, and lc of one nokloop, and has piping 15a, 15b, respectively.

15a, and the other low pressure side accumulator 305 is connected to the injector Id of the other group.
, 1erlf, and the piping 15d, 15e, respectively.
It is connected via 15f.

The configuration of each accumulator 204, 205, 304 and 305 is as shown in FIG. It is set to 100 times.

The structure of each injector 1a to 1f is shown in FIG.
This will be explained using the injector as a representative.

What about Inzoecta 1&? A switching valve 5, such as a spool valve, which slides from side to side in Fig. 3 while maintaining oil tightness inside 76.7; It consists of a small-diameter sliding sylanger 8 and a large-diameter piston 9, an injection nozzle 10 that receives fuel fed under pressure from the sylanger 8, and three electromagnetic valves 11, 12, and 13. The inside of the zea 4 on one side of the switching valve 5 forms a switching valve operating oil chamber 14 , and this chamber 14
communicates with the low-pressure side accumulator 304 via the solenoid valve 1, which is a three-way on-off valve, and piping 15a, and is also connected to the fuel reservoir tank 16 through the solenoid valve 12, which is also a three-way on-off valve.

A spring 17 on the opposite side of the hydraulic fluid chamber 14 presses the switching valve 5 to the left in the figure, that is, in a direction that makes the hydraulic fluid chamber 14 smaller. A piston hydraulic oil chamber 18 is formed by the inside of the groove 74 in the middle small diameter portion of the switching valve 5 and the male hole 7 on the upper side of the piston 9. This piston hydraulic oil chamber 18
is selectively communicated with the two ports 19 and 20 depending on which of the two left and right positions the switching valve 5 is in. One of the ports 19 is returned to the high side accumulator 204 through the connection W21a, and the other 61J-to 20 is returned to the tank 16 via the throttle υ22.

A pump hydraulic oil chamber 23 formed in the bore 6 on the lower side of the plunger 8 communicates with the nozzle 10, and also communicates with the nozzle 10, and also provides low pressure via the check valve 24 and the above-mentioned metering solenoid valve 13, which is a three-way on-off valve. It communicates with the side accumulator 304. The control device 300 Å port is electrically connected to various sensors (not shown), and the output port is connected to the three electromagnetic valves 11 described above.
, 12, 13 and sends control signals to them.

The fuel supply devices 2, 3 constitute a normal constant hydraulic pressure source consisting of pumps f2ox, so1, relief valves 202, 302, and filters 203, 303.

The operation of the injectors 1a to 1f having the above-mentioned configuration will be described using the injectors 1& in FIG.
In the illustrated position, the solenoid valve 11 is closed and the solenoid valve 1
2 is open, the high pressure side fuel supply source 2 is separated from the switching valve operating oil chamber 14, and this chamber 14 is connected to the reservoir tank 16.
I understand. Therefore, due to the spring 17, the switching valve 5 is in the left position (), J-) 20 is brought into communication with the piston hydraulic oil chamber 18, and the fuel in this chamber 18 is transferred to the reservoir tank 1.
6, it will be in a state where it can be released. In this state, the solenoid valve 13
When a signal giving a valve opening time corresponding to the injection amount is input from the control device 30, the valve is opened for this period as shown in the figure, and the fuel from the low pressure side fuel supply source 3 is pumped through the check valve 24. The hydraulic oil chamber 23 is introduced and filled with a predetermined amount, and then the metering solenoid valve 13 is closed. At this time, the piston 9 and sylanger 8 rise.

When the solenoid valve 11 is opened and the other solenoid valve 12 is closed, the hydraulic pressure from the low-pressure side fuel supply source 3 acts on the switching valve operating chamber 14 through the pipe 15m, and at the same time, this chamber 14 acts on the reservoir tank. It is separated from 16. As a result, the switching valve 5 moves to the right in the drawing against the spring 17, closing the port 20 and opening the port 19. In this way, the hydraulic pressure from the high-pressure side fuel supply source 2 is transferred to the piston hydraulic oil chamber 18 through the piping 2 and
This oil pressure causes the piston 9 and the granger 8 to move downward. At this time, an extremely high pressure is generated in the pump working oil chamber 23, which theoretically increases the pressure in the ponder chamber 23 to twice the piston-to-grander cross-sectional area ratio of the hydraulic pressure of the high-pressure side fuel supply source 2. This ultra-high pressure fuel is prevented from flowing back by the check valve 24, is supplied to the nozzle 10, and is injected into a combustion chamber of an internal combustion engine (not shown).

The above is the operation during normal operation, and this will be further explained with reference to the timing diagram of FIG. 4.

When the second solenoid valve 12 is closed and the first solenoid valve 11 is opened at timing A, the susol moves to the right by the hydraulic pressure, and then the piston and granger are pushed down, injecting fuel. .

Next, at timing B, the first solenoid valve 11 is closed and the second solenoid valve 12 is opened, and the sugur is pushed back to the left. The second solenoid valve 12 is then closed. In this state, the third solenoid valve is opened at timing C and kept open until timing D. During this period, the silant and piston 9- are pushed up and the injected fuel is introduced. What is shown in FIG. 3 is the state during this period. When the third solenoid valve is closed at timing D, timing A of the next cycle returns in that state. It can be seen that the injection amount is controlled at this time by the time CD. Therefore, in the case of partial load, the controlled valve opening time becomes CD (as shown by the broken line in the figure).

As can be understood from the action of the injector 1a as described above, when each injector IIL to 1f injects fuel,
Since the fuel pressure is suddenly released, the pressures of the high-pressure fuel supply source 2 and the low-pressure fuel supply source 3 drop instantaneously. However, as in the configuration shown in FIG.
Since the pressure is accumulated in 205, 304, and 305, it is possible to prevent an adverse effect due to a decrease in fuel pressure. That is, to explain in terms of the high pressure side accumulators 204 and 205,
The injectors whose injection orders are different from each other are divided into groups, and a set of injectors 1a to 1c (10-) to (1) and a set of injectors 1d to 1f (■■■) are grouped.

Since the accumulators 204 and 205 are connected to each other, as shown in FIG. 5, the pressure fluctuation of each accumulator 264 and 205 corresponds to every other injection order. In the individual accumulators 204, 205, the time interval between the pulsating pressures becomes longer, so that earlier pulsations no longer influence subsequent injections. Since pulsation is prevented, stable fuel pressure can be applied to the injectors 1a to 1f, and variations in injection characteristics among the injectors 18 to lf can be prevented.

FIG. 6 shows an example of a conventional device installed close to a single accumulator. As can be seen from the characteristic diagram in Fig. 7, in this case, the time interval of pressure fluctuations in the accumulator 204 is short, and the next injection starts before the pulsation caused by the previous injection is completely resolved. Therefore, variations in injection characteristics are likely to occur due to pulsation.

In addition, each accumulator 204, 205, 304゜305
Since each accumulator 204, 205, 304, .
There is no need to significantly increase the size of 305.

Furthermore, from the perspective of piping layout, in the case of the conventional example shown in FIG. 6, long piping is required from the achievers 204 and 304 to each of the injectors lh to 1f, so many long pipings are required. However, piping work is troublesome and the surroundings of the engine 100 are complicated.

On the other hand, in the embodiment shown in FIG. The piping 211-21f and 15a-15f connecting the 304° SOS and the injectors 1a-1f can be short.

Piping 21x connects the accumulators 204, 205, 304° 305 and the fuel supply sources 2, 3.

21y, 15x, and 15y are longer, but since the total number of these is small, piping work is easier.
The surrounding area is simplified and the space module is small.

Note that the present invention is not limited to the embodiment shown in FIGS. 1 to 5. For example, in the case of a six-cylinder engine, an accumulator may be used for every two injectors as a grouping of accumulators. Further, the configuration of the injector is not limited to that shown in FIG. 3, and therefore, the accumulator is not limited to being used on the high pressure side and the low pressure side. Further, as the accumulator, other structures such as a bladder type, diaphragm type, and piston type can also be used.

As described above, according to the present invention, since a single accumulator is provided for each 13-group of injectors whose injection order is different from each other, each accumulator is affected by the injection pulsation of the injectors. Therefore, the pressure inside the accumulator is stabilized, the pressure supplied to the injector is also stabilized, the injection characteristics become uniform, and the accumulator can be made smaller. In addition, since the accumulator is placed close to the injector, the piping has a simple structure, and even though multiple accumulators are used, the accumulator is small and the piping is single. This has the advantage that the space around the engine can be made smaller.

[Brief explanation of the drawing]

Figures 1 to 5 show an embodiment of the present invention, with Figure 1 being an overall configuration diagram, Figure 2 being a sectional view of an accumulator, Figure 3 being a configuration diagram of an injector, and Figure 4 being an injector configuration diagram. FIG. 5 is a characteristic diagram showing the pressure fluctuation of the accumulator. FIG. 6 is a block diagram of the conventional device, and FIG. 7 is a pressure fluctuation characteristic diagram of the 14th accumulator. 100... Engine, 1a-1f... Injector, 2, 3... Fuel supply source, 204, 205° 304.
305...accumulator, 211L to 21f,
21 x, 21 y---Piping, 15a to 15f
. 15x, 15y...Piping. Applicant's attorney Takehiko E Takehiko 15- Figure 2 Takehiko 6M Figure 5 Time η7 LibiN Figure 7 Pressure review

Claims (1)

[Claims] In a fuel injection device that distributes and injects fuel to each cylinder from a common fuel supply source using injectors provided for each cylinder, each injector is divided into multiple groups with different injection orders, and each A fuel injection device for a multi-cylinder internal combustion engine, characterized in that a single accumulator is provided adjacent to each group, and fuel is distributed and supplied to each injector from the fuel supply source through the accumulator.