JPH0216042Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is an engine fuel supply system, in particular, a fuel supply system for an engine, in which a surge tank defining an enlarged chamber is provided in the middle of the intake system, and an independent intake passage downstream of the surge tank is provided. The present invention relates to a fuel supply device for an engine equipped with an injector that injects fuel.

(Prior art) In order to improve engine output, it is effective to increase the filling efficiency of intake air into the cylinder.
Attempts have been made to utilize dynamic effects of intake air, such as inertial effects or resonance effects. This kind of effect
In order to use it in a multi-cylinder engine, in order to avoid intake interference between each cylinder, a surge tank defining an enlarged chamber with a required volume is provided in the middle of the intake system, and the surge tank and the It is necessary to connect each cylinder with an independent intake passage.
As a result, the intake system, especially the surge tank, is located higher, making the overall engine larger. In particular, in an engine that supplies fuel to each cylinder by an injector, the injectors are installed in independent intake passages downstream of the surge tank, and a fuel distributor that distributes fuel to each injector is installed. Since it is connected to the head of the injector, the surge tank must be installed further away from the engine body in order to prevent the injector or distributor from interfering with the surge tank. It becomes larger.

By the way, according to Japanese Patent Application Laid-open No. 56-101055,
In a V-type engine, a configuration is shown in which a surge tank is provided in the middle of the intake system, and injectors are installed in independent intake passages leading to each cylinder downstream of the surge tank. In this case, a fuel destroyer that distributes and supplies fuel to each injector is integrally provided within the wall of the surge tank. According to this, the destroyer and the surge tank can be separated. The surge tank can be placed closer to the bank and the overall height of the engine can be lowered compared to when the surge tank is installed. Further, the fuel in the fuel distributor is cooled by the air passing through the surge tank, which has the advantage of preventing fuel percolation.

However, regarding what is shown in this bulletin,
The fuel destroyer connected to each injector is integrally formed with the surge tank, and this surge tank is directly connected to each injector, so when removing it for inspection, repair, or replacement of the injector, The surge tank had to be removed each time, resulting in extremely poor serviceability.

(Purpose of the invention) The present invention deals with the above-mentioned problems regarding the engine fuel supply system, and includes a surge tank defining an expansion chamber in the middle of the intake system, and a surge tank on the downstream side of the surge tank. In the case where an injector is installed in each independent intake passage, this kind of type makes it possible to install a fuel distributor that distributes and supplies fuel to each injector in the enlarged chamber without deteriorating the serviceability of the injector etc. An object of the present invention is to provide a fuel supply device for an engine that can suppress the increase in size of an engine.

(Structure of the invention) In order to achieve the above-mentioned object, in the present invention, a surge tank defining an expansion chamber is provided in the middle of the intake system, and an injector is installed in each independent intake passage on the downstream side of the surge tank. A fuel destroyer that supplies fuel to each of the above injectors is removably installed in the expansion chamber, and each injector connection part of this destroyer is connected to a hole provided on the wall of the surge tank. They are made to protrude outward in the same direction, and the injectors are respectively connected to these protrusions. In addition, the fuel pipe connection part of the fuel destroyer, which is the connection part to the fuel pipe for supplying or discharging fuel to the fuel destroyer, is connected to the above-mentioned injector connection part through a hole provided in the wall of the surge tank. It is made to protrude outside in the same direction, and the fuel pipe is connected to this protrusion.

According to this configuration, by providing the fuel destroyer inside the surge tank, that is, in the expansion chamber, it becomes possible to arrange the surge tank close to the engine body, thereby making the entire engine more compact. Further, the fuel destroyer is removable from inside the expansion chamber, that is, the surge tank, and an injector or a fuel pipe is connected to a portion of the fuel destroyer that protrudes in the same direction from the outside of the surge tank. Therefore, the injector or fuel pipe can be easily removed by simply removing the fuel destroyer from one predetermined direction, improving serviceability.

(Example) Hereinafter, an example of the present invention will be described based on the attached drawings.

In FIG. 1 showing a V-type engine, an engine 1 has two banks 4 each formed of a plurality of cylinders 2 and installed in a V-shape at a certain angle around a crankshaft 3. An intake device 5 is installed above the center of the bank 4.

The intake device 5 includes a main intake passage 6 led from an air cleaner (not shown), a surge tank 7 whose one end face is connected to the downstream end of the main intake passage 6, and an upstream intake passageway connected to both sides of the surge tank 7. It is comprised of independent intake passages 9 having a required length and independent from each other, the ends of which are connected, and the downstream ends of which are connected to the intake ports 8 of the cylinders 2 in both banks 4, respectively. In this embodiment, the inside of the surge tank 7 is partitioned into left and right enlarged chambers 11 by a partition wall 10 in the crankshaft direction, and each independent intake passage 9 has its upstream end connected to the left enlarged chamber 11. are connected to cylinder 2 of bank 4 on the right side, and each independent intake passage 9 whose upstream end is connected to expansion chamber 11 on right side is connected to cylinder 2 of bank 4 on left side, respectively, and extends from both sides of surge tank 7, respectively. Independent intake passage 9
are crossed below the surge tank 7. Further, each independent intake passage 9 has an upstream portion 9 bent in a U shape.
The surge tank 7 has a two-part structure including a downstream part 9b and a downstream part 9b which intersect with each other, and each downstream part 9b is integrally formed with the surge tank 7.

At the downstream end of each independent intake passage 9, as shown in an enlarged view in FIG. A pair of left and right fuel distributors 13 are installed in the expansion chambers on both sides of the surge tank 7 to distribute and supply fuel to the plurality of injectors 12 in the corresponding side banks 4. . This distributor 13 is a bolt 1
4 is attached to the inner bottom surface of the surge tank 7 (expansion chamber 11), and the injector 12
The connecting portion 13a extends downwardly through a hole 7a formed in the bottom wall surface of the surge tank 7, and the head 12b of each injector 12 is fitted into the projecting portion. As a result, each injector 12 is fixed, and the fuel supplied to the fuel distributor 13 from a separately provided fuel pump (not shown) via a fuel pipe (to be described later) is common to the distributor 13. Passage 13
It is distributed to each injector 12 via a branch passage 13c passing through the insides of the injectors 13b and 13a.
Here, the common lines 13b of the fuel destroyers 13 installed in the enlarged chambers 11 on both sides are communicated with each other by a communication pipe 15 penetrating the partition wall 10, and the upper surface of the surge tank 7 is connected to the mounting of the destroyer 13. It is opened for removal, etc., and is closed by a cover 16.

Further, a fuel pipe connecting portion 13d is formed at each end of each fuel destroyer 13, as shown in FIGS. 3 and 4, and this fuel pipe connecting portion 13d is also connected to the surge tank 7. It penetrates a hole 7b formed in the bottom wall surface and projects downward. Then, on the right, Fuel Destributor 1
The fuel pipe connecting portion 13d of No. 3 extends in the same direction as each injector connecting portion 13a of the right fuel destroyer 13, and similarly, the fuel pipe connecting portion 13d of the left fuel destroyer 13 extends in the same direction as each injector connecting portion 13a of the fuel destroyer 13 on the right side. Connection part 1 for each injector in this fuel destroyer 13 on the left side
It extends in the same direction as 3a. Of the fuel pipe connections 13d provided on the left and right fuel distributors 13, the one on the right side in FIG. 4 is for fuel inflow and extends from the fuel pump (not shown) via the pulsation damper 17. A fuel supply pipe 18 is connected. Further, the fuel pipe connecting portion 13d on the left side of FIG. 4 is for discharging fuel, and a fuel return pipe 20 extends to the upstream side of the fuel pump via the pressure regulator 19.
is connected. Of course, the passage 13e in each fuel pipe connecting portion 13d is connected to the common passage 13b. And pulsation damper 1
7. The pressure regulator 19 is connected to (the passage 13e of) the fuel pipe connection part 13d,
Tightly connected by screwing, that is, both 1
7 and 19 are fixed to the fuel destroyer 13. In the embodiment, the pulsation damper 17 and pressure regulator 19 are as shown in FIG.
They are arranged at the ends of the fuel destroyer 13 in the same direction to facilitate the handling of the fuel pipes 18 and 20.

According to the above configuration, intake air taken in from an air cleaner (not shown) flows from the main intake passage 6 into both enlarged chambers 11 of the surge tank 7, and is distributed and flows from both enlarged chambers 11 into a plurality of independent intake passages 9, respectively. The fuel is then supplied to each cylinder 2 in the two banks 4, respectively. In that case, the intake air is in the expansion chamber 11
Since each cylinder 2 passes through an independent intake passage 9 having a predetermined length on the downstream side of the cylinder 2, a pulsation effect and an inertia effect of the intake air can be obtained between them.
A resonance effect is obtained due to the resonance of the intake system including the main intake passage 6 and the main intake passage 6 on the upstream side thereof, and these effects improve the filling efficiency of intake air into each cylinder 2.

On the other hand, the fuel pumped from the fuel pump passes through the fuel supply pipe 18 and the pulsation damper 17, and is supplied to the fuel distributor 13 from the fuel pipe connection 13d on the right side of FIG. The pulsation damper 17 alleviates the pulsation of the fuel. Moreover, the surplus fuel in the fuel destroyer 13 is passed from the fuel pipe connection part 13d on the left side of FIG. 4 to the pressure regulator 19 and the fuel return pipe 20.
Although the fuel is returned to the upstream side of the fuel pump, the pressure regulator 19 maintains the fuel pressure in the fuel distributor 13 at a predetermined pressure.

The fuel supplied to the fuel destroyer 13 is passed through the common passage 13b of both destroyers 13.
The fuel is then distributed and supplied to the injectors 12 connected to the branch passages 13c through each branch passage 13c, and further injected into the intake port 8 of each cylinder 2 by the injector 12.

Here, the head 12b of each injector 12 is
The fuel destroyer 13 connected to
Since it is installed inside the surge tank 7 (expansion chamber 11), the surge tank 7 is installed lower, that is, closer to the engine body, compared to when it is installed separately outside the surge tank 7. This makes it possible to reduce the overall height of the engine 1. Further, since the distributor 13 is provided in the surge tank 7, the distributor 13 is protected from the outside, and the fuel in the distributor 13 is cooled by the air passing through the surge tank 7. Percolation due to heating is prevented. Furthermore, even if fuel leaks downstream from both distributors 13 and the communication pipe 15 that communicates the two, the fuel will accumulate in the surge tank 7 and will be prevented from leaking to the outside.

Here, the fuel destroyer 13 is glued to the inner bottom surface of the surge tank 7 with a bottle 14, and the connecting portion 13 of the destroyer 13 is glued to the inner bottom surface of the surge tank 7.
a and 13d protrude outward in the same direction from holes 7a and 7b provided in the bottom wall of the surge tank 7, so the bolts 14 are removed after removing the cover 16 that closes the top surface of the surge tank 7. By removing the distributor 13, the distributor 13 can be easily removed from the surge tank 7. When the distributor 13 is removed, the head 12b of the injector 12 becomes free, and the distal end 12a can be pulled out from the hole 9c of the independent intake passage 9. By removing it, the injector 12 can also be easily removed. In other words, the distributor 13 and the injector 12 can be removed or attached without removing the surge tank 7. Of course, the pulsation damper 19 and the pressure regulator 19 are removed from the connecting portion 13d before the fuel distributor 13 is removed.

In this embodiment, since the surge tank 7 and the downstream part 9b of the independent intake passage 9 are integrally formed, the hole 7a through which the connecting part 13a of the distributor 13 on the bottom wall of the injector passes, and the independent intake passage 9 are formed integrally. Injector mounting hole 9 in downstream part 9b
The centers of c are aligned with high accuracy, and therefore the injector 12 can be fixed and positioned reliably and accurately.

Moreover, if the pulsation damper 17 and the pressure regulator 19 are connected and fixed to the connection part 13d of the fuel destroyer 13 as in the embodiment, the injector is located below the surge tank 7. The space under the surge tank 7, which is inevitably formed due to the presence of the surge tank 12, can be effectively utilized for its arrangement. Further, the pulsation damper 17 and the pressure regulator 19 are connected to the fuel pipe 18 or 2.
Although it may be installed in the middle of the surge tank 7, if it is installed near the surge tank 7 by effectively utilizing the space below it as in the embodiment, it can effectively absorb fuel pulsations and also provide a fuel destroyer. This is preferable for maintaining the fuel pressure within the fuel pressure at a predetermined pressure (improving responsiveness to fuel pressure fluctuations).

Incidentally, in the case of a type of fuel distributor that does not discharge surplus fuel, the connection portion 13d for discharging fuel is not necessary.

(Effects of the invention) As is clear from the above, the invention has the following effects:
Since the fuel destroyer is installed inside the surge tank, that is, in the expansion chamber, the overall height of the surge tank can be lowered by placing the surge tank as close to the engine body as possible compared to when the fuel destroyer is installed separately from the surge tank. can.

Furthermore, while the fuel destroyer is removably installed inside the surge tank, all the connecting parts of the fuel destroyer that protrude to the outside of the surge tank are extended in the same direction. Since the fuel destroyer and the injector can be easily pulled out from the hole of the surge tank and the injector can be easily removed, the fuel destroyer and the injector can be easily serviced or assembled.

Furthermore, the fuel destroyer is effectively protected from the outside by the surge tank, and even if fuel leaks from the fuel destroyer inside the surge tank, this leaked fuel is prevented from leaking outside. In addition to this, the air passing through the expansion chamber cools the fuel destroyer, making it possible to prevent fuel percolation and the like.

Furthermore, since all the connecting portions of the fuel destroyer are formed to protrude in the same direction, this fuel destroyer can be easily manufactured by casting or the like.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an embodiment of the present invention.
FIG. 2 is an enlarged sectional view of the main part of FIG. 1. FIG. 3 is a partially omitted plan view of the surge tank with the cover removed. FIG. 4 is a sectional view taken along the line of FIG. 3. DESCRIPTION OF SYMBOLS 1... Engine, 5... Intake device, 7... Surge tank, 7a, 7b... Hole, 9... Independent intake passage, 11... Expansion chamber, 12... Injector, 1
3...Fuel destroyer, 13a...Injector connection part, 13d...Fuel pipe connection part, 18, 19...Fuel pipe.

Claims (1)

[Claims for Utility Model Registration] An engine comprising: a surge tank provided in the middle of an intake system and defining an enlarged chamber; and an injector that injects fuel into an independent intake passage downstream of the surge tank, the engine comprising: A fuel destroyer for supplying fuel to the injector is removably installed in the expansion chamber, and a connection part for each injector of the fuel destroyer is connected in the same direction from a hole provided in the wall of the surge tank. The injector is connected to the protruding part of the fuel distributor, and the fuel pipe connection part of the fuel distributor is extended from a hole provided in the wall of the surge tank to the outside in the same direction as the injector connection part. A fuel supply device for an engine, characterized in that the protrusion is connected to a fuel pipe.