JPH0347464A - Fuel supply device for engine - Google Patents

Abstract

PURPOSE:To enhance the performance of an engine by furnishing a plurality of a fuel injection valves, and displacing them fore and aft along the longitudinal direction of a suction passage. CONSTITUTION:No.1 fuel injection valve 19 corresponding to a divergent passage 11 with short reach time is located near the combustion chamber 7 while No.2 fuel injection valve 20 corresponding to another divergent passage 11' with a longer reach time is positioned farther from the combustion chamber 7 than the first named valve 19. When this injection valve 19 has injected fuel, it reaches the combustion chamber 7 in a short time, but because of short reach time in the divergent passage 11 the fuel injected into the suction air is mixed thoroughly with the suction air and supplied to the combustion chamber 7. When the injection valve 20 injects the fuel, on the other hand, the time of the fuel reaching the combustion chamber 7 becomes longer in the amount corresponding to the injection valve 20 being apart from the combustion chamber 7. Even with longer reach time, therefore, the fuel injected into the suction air is thoroughly mixed with the suction air until reaching the combustion chamber 7.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel supply device for an engine that includes a fuel injection valve that injects fuel into an intake passage having a plurality of branch passages.

(Prior Art) Some engine intake systems are configured as follows in order to increase intake efficiency.

That is, an intake passage connected to a combustion chamber in the cylinder is branched into a plurality of branch passages from a midpoint thereof to the combustion chamber, and an intake valve is provided to open and close each of the branch passages opening into the combustion chamber. , and a fuel injection valve for injecting fuel into the intake passage.

When each of the intake valves opens and air is forcefully sucked into the combustion chamber through the intake passage, the fuel injected by the fuel injection valve is agitated and mixed by the intake air to form an air-fuel mixture. It is supplied into the combustion chamber and burned there.

(Problems to be Solved by the Invention) Incidentally, each of the above-mentioned branch passages has a different length and shape, and therefore the flow resistance of the intake air in these branch passages is different from each other. Therefore, with the time when the intake valve opens as the reference time, the time from this reference time until the flow velocity of the intake air in the branch passage reaches a predetermined velocity (hereinafter simply referred to as arrival time) is the time for each branch passage. They are different from each other.

In this case, when fuel is injected into the intake air, the fuel is supplied to the combustion chamber together with the intake air before the flow velocity of the intake air reaches a predetermined speed in the branch passage where the arrival time is long. In this case, the intake air and fuel may not be sufficiently mixed, which may impede improvement in engine performance.

(Object of the Invention) This invention was made in view of the above-mentioned circumstances, and is designed so that, in any branch passage, fuel is sufficiently mixed with the intake air before it is supplied to the combustion chamber. The purpose is to improve engine performance.

(Structure of the Invention) A feature of the present invention for achieving the above object is that a plurality of fuel injection valves are provided and these fuel injection valves are offset back and forth along the longitudinal direction of the intake passage. .

(for production) The effects of the above configuration are as follows.

When the intake passage 9 is branched into a plurality of branch passages 11.11' from its midpoint to the combustion chamber 7, the intake valve 12.1
From this reference time, the time for the intake flow velocity in each branch passage 11 and 11' to reach a predetermined velocity (the above-mentioned arrival time)
．． 11. ' are different from each other.

Therefore, in this invention, a plurality of first and second fuel injection valves 1
9.20 are provided, and these fuel injection valves 19.20 are offset back and forth along the longitudinal direction of the intake passage 9.

In this case, among the fuel injection valves 19.20,
The first fuel injection valve 19 corresponding to the branch passage 11 with a short arrival time is located near the combustion chamber 7, and the other second fuel injection valve 20 corresponding to the branch passage 11' with a long arrival time is located near the first fuel injection valve 19. If the fuel injection valve 19 is located farther from the combustion chamber 7 than the fuel injection valve 19, when the first fuel injection valve 19 injects fuel, the fuel will reach the combustion chamber 7 in a short time, but in this branch passage 11, the arrival time will be shorter. As described above, since the length is short, the fuel injected into the intake air is sufficiently mixed with the intake air and supplied to the combustion chamber 7.

On the other hand, when the second fuel injection valve 20 injects fuel, the time for this fuel to reach the combustion chamber 7 is
0 is far away from the combustion chamber 7, the length becomes longer.
Therefore, even if the arrival time is long, the fuel injected into the intake air will be sufficiently mixed with the intake air before reaching the combustion chamber 7.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

(First example) 1 to 3 show a first embodiment.

In Figures 1 and 2, l is a four-stroke engine installed in a car, cylinders 2 of this engine l are arranged side by side to form a cylinder block 3, and a cylinder head 4 is mounted on the cylinder block 3. A piston 6 connected to a crankshaft is fitted into the cylinder 2 so as to be vertically slidable. A space surrounded by the cylinder block 3, cylinder head 4, and piston 6 is a combustion chamber 7, and a spark plug 7a facing approximately the center of the combustion chamber 7 is provided.

An intake passage 9 is formed on the left side of the cylinder head 4 (referring to the direction as viewed in FIG. 1, hereinafter referred to as the same), which extends from the surge tank 8 to the combustion chamber 7. This intake passage 9 is formed of a main passage 10 connected to the surge tank 8, and three branch passages 11.11' branching from this main passage IO toward the combustion chamber 7. These branch passages 11.1
The middle branch passage 11 of the combustion chamber 1' is located on an extension of the main passage 1O in plan view (FIG. 2) and extends toward the center of the combustion chamber 7. Further, the branch passages 11 and 11' on both sides are substantially symmetrical with the intermediate branch passage 11 in between, and both extend toward the side of the combustion chamber 7.

The above branch passage 11. ．． The branch boats lla' and Ila' whose 11' opens into the combustion chamber 7 have the same diameter, and are arranged in parallel on the left upper surface of the combustion chamber 7 in the substantially circumferential direction of the two Schilling axes. For this reason, the branch passages 11', 11' on both sides are longer in length than the intermediate branch passage 11.

In addition, intake valves 12.12' are provided to open and close the above branch ports 11a and 11a, and intake valves 12.12' are provided to open and close the above branch ports 11a and 11a.
A spring 14 is provided which biases the '.

A cam chamber 15 formed in the upper part of the cylinder head 4 is provided with an intake camshaft 16 that interlocks with the crankshaft. This intake camshaft 16 is connected to the intake valve 12.12'.
The intake valves 12 and 12' are appropriately opened against the spring 14 in synchronization with the crankshaft. At this time, these intake valves 12 and 12' are opened and closed at the same time.

By the way, as mentioned above, each intake valve 12, 12' opens and closes at the same time, but as mentioned above, the intermediate branch passage 11
Since the length of the branch passages 11'11' on both sides is longer than that, the arrival time is short in the middle branch passage 11.
In comparison, the arrival time is longer in each of the branch passages 11' on both sides.

Meanwhile, two first and second fuel injection valves 19 and 20 are provided to inject fuel into the intake passage 9.

These are located above the intake passage 9, when viewed from above (Fig. 2)
It is located on the hole center of the main passage 10 and the intermediate branch passage 11, and is offset back and forth along the longitudinal direction of the intake passage 9.

The first fuel injection valve 19 has one injection hole, and the fuel injection direction 19a thereof intersects the hole center of the intermediate branch boat lla, that is, the first fuel injection valve 19 has one injection hole. It is provided corresponding to the passage 11. on the other hand,
The second fuel injection valve 20 has two injection holes, and the fuel injection directions 20a, 20a thereof intersect with the hole centers of the corresponding branch boats 11a' on both sides, that is,
This second fuel injection valve 20 has branch passages 11' and 11 on both sides.
' has been set up correspondingly.

That is, according to the above configuration, the first fuel injection valve 19 corresponding to the intermediate branch passage 11 having a short arrival time is located near the combustion chamber 7 (
Branch passages 11' and 11' on both sides with long arrival times are located at
The second fuel injection valve 20 corresponding to ' is located farther from the combustion chamber 7 than the first fuel injection valve 19.

Meanwhile, a pair of exhaust boats 23 and 23 are formed on the right side of the cylinder head 4 to communicate the combustion chamber 7 with the outside. Exhaust valves 24 and 24 that open and close each of these exhaust ports 23
An exhaust valve 24 is provided to close each exhaust port 23.
A spring 25 is provided to bias the . Further, the cam chamber 15 is provided with an exhaust camshaft 26 that is interlocked with the crankshaft. This exhaust camshaft 26 is connected to each exhaust valve 2 mentioned above.
4, and opens these exhaust valves 24 appropriately against a spring 25 in synchronization with the crankshaft.

In FIG. 3, during the exhaust and intake strokes of the engine 1, each exhaust valve 24 and each intake valve 12.12' sequentially open and close, and each intake valve 12.12' simultaneously opens. The fuel injection valves 19 and 20 simultaneously inject fuel from immediately before to immediately after operation and immediately before the piston 6 reaches the top dead center, as shown by arrow A in the figure.

The fuel injected into the intake passage 9 is mixed with the intake air passing therethrough. The air-fuel mixture is then supplied to the combustion chamber 7 through the branch passage 11.11' and combusted there, and then the combustion gas is transferred to the exhaust boat 23.2.
It is discharged through 3.

In addition, as shown by the imaginary line in FIG. 1, the second fuel injector 20
The fuel injection valves 19 and 20 may be installed at the lower side of the intake passage 9. Also, since the installation of each fuel injection valve 19 and 20 is the above problem, for example, the second fuel injection valve 20 may be placed close to the first fuel injection valve 19. 3, the injection timing of the second fuel injector 2 as shown by the arrow B is higher than the injection timing of the first fuel injector 19 shown by the arrow A in FIG.
0 injection timing may be slightly delayed. Also, contrary to the above, when disposing the second fuel injection valve 20 apart from the first fuel injection valve 19, the first fuel injection valve 19 and the second fuel injection valve The injection timings of the two fuel injection valves 20 may be reversed.

The following figures show the second to fourth embodiments, all of which have the same basic configuration and operation as the first embodiment. Therefore, the common configurations will be designated by reference numerals in the drawings and their explanations will be omitted, and only the different configurations will be explained.

(Second example) FIG. 4 shows a second embodiment.

According to this, the first fuel injection valve I9 has three injection holes, the fuel injection direction 19a by one of them is the same as that of the first embodiment, and the fuel injection direction by the other two is the same as that of the first embodiment. 19a, 19a are branch boats lla on both sides,
It intersects the hole center of 11a'.

(Third example) FIG. 5 shows a third embodiment.

According to this, the first fuel injection valve 19 injects fuel in a fan shape or a conical shape over the entire angle α between the fuel injection directions 19a and 19a' on both sides in the second embodiment. Further, the second fuel injection valve 20 also injects fuel in a fan shape or a cone shape over the entire angle β between the fuel injection Q=1 directions 20a and 20a on both sides.

Note that the angle α is almost the same as the angle β, and therefore, the fuel injection directions 19a on both sides of the first fuel injection valve 19,
19a is the branch port 11a on both sides, lla'
The center of the combustion chamber 7 is closer to the center of the hole than the center of the hole.

(Fourth example) 6 to 8 show a fourth embodiment.

In FIGS. 6 and 7, the diameter of the branch ports 11a and 11a' on both sides is smaller than the diameter of the intermediate branch port 11a. However, the speed of intake air increases. In addition, the opening timings of the intake valves 12', 12' on both sides, indicated by solid lines, are earlier than that of the middle intake valve 12, indicated by broken lines in FIG. Therefore, the intake valves 12' on both sides
, 12' as the reference time, the arrival time is short in the branch passages 11' and 11' on both sides.
In comparison, the arrival time in the middle branch passage 11 is longer.

On the other hand, the first fuel injection valve 19 has two injection holes, and each fuel injection direction '19a' is located at the center of the hole in the intermediate branch boat lla on the upper surface of the combustion chamber 7 in a side view (Fig. 6). and the hole centers of the branch ports 11a' on both sides, and intersects with the hole centers of the branch boats Ila' on both sides in plan view (FIG. 7). Further, the second fuel injection valve 20 has one injection hole, and the fuel injection direction 20a' thereof intersects the hole center of the intermediate branch boat IIa in plan view.

That is, even with the above configuration, the first fuel 1!1 injection valve 19 corresponding to the branch passages 11', 11' on both sides having a short arrival time
is located near the combustion chamber 7, and the second fuel injection valve 20 corresponding to the intermediate branch passage 11 having a long arrival time is located further from the combustion chamber 7 than the first fuel injection valve 19.

In addition, as shown by the imaginary line in FIG. 6, the second fuel injector 2
Similarly to the fuel injection direction 19a of the first fuel injection valve 19 when viewed from the side, the fuel injection direction 208' of No. The intermediate intake valve 12 may also pass through the
There may be a deviation between the valve operation of the intake valves 12' and 12' on both sides, as shown by the two-dot chain line or the - dot chain line in Fig. 8. According to the example, the branch ports 11a, 1
1a may be two or four.

(Effects of the Invention) According to the present invention, the intake passage connected to the combustion chamber in the cylinder is branched into a plurality of branch passages from its midpoint to the combustion chamber, and each of the branch passages opens into the combustion chamber. In an engine that is provided with an intake valve that opens and closes each of the intake passages, and a fuel injection valve that injects fuel into the intake passage, the fuel injection valves are arranged in multiple stages, and these fuel injection valves are arranged in front and back along the longitudinal direction of the intake passage. Because of the deviation, one of the fuel injection valves corresponding to the branch passage with a short arrival time is located near the combustion chamber, and the other fuel injection valve corresponds to the branch passage with a long arrival time. is located farther from the combustion chamber than one of the fuel injection valves, when the one of the fuel injection valves injects fuel, the fuel reaches the combustion chamber in a short time, but in this branch passage, the arrival time is shorter. As described above, since the length is short, the fuel injected into the intake air is sufficiently mixed with the intake air and supplied to the combustion chamber.

On the other hand, when the other fuel injector injects fuel, the time it takes for this fuel to reach the combustion chamber becomes longer as this fuel injector is further away from the combustion chamber. Therefore, even if the arrival time is long, the fuel injected into the intake air will be sufficiently mixed with the intake air before reaching the combustion chamber, improving engine performance.

(Margin below) Therefore,

[Brief explanation of drawings]

The figures show embodiments of the invention, and Figures 1 to 3 are
In the embodiment, FIG. 1 is an overall side sectional view, FIG. 2 is a simplified plan view, and FIG. 3 is a graph. Figures 4 and 5 show the second and third embodiments, both of which correspond to Figure 2, and Figures 6 to 8 show the fourth embodiment, with Figure 6 being a partial side cross section. FIG. 7 is a simplified plan view, and FIG. 8 is a graph. l...Engine, 2...Cylinder, 7...Combustion chamber, 9...
・Intake passage, 11.11' ・Branch passage, 12.1
2'...Intake valve, 19...First fuel injection valve, 20...
・Second fuel injection valve.

Claims (1)

[Claims] 1. An intake passage connected to a combustion chamber in a cylinder is branched into a plurality of branch passages from an intermediate part thereof to the combustion chamber,
In an engine that is provided with an intake valve that opens and closes each of the branch passages that open into the combustion chamber, and is provided with a fuel injection valve that injects fuel into the intake passage, a plurality of the fuel injection valves are provided, and these fuel injection valves are connected to the intake passage. Fuel supply system for the engine offset back and forth along the longitudinal direction of the engine.