JPH0465232B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a fuel-injected internal combustion engine.

A fuel injection valve is provided in the intake passage, and the intake passage downstream of the fuel injection valve is divided into two into a first intake passage and a second intake passage by a partition wall extending along the axis of the intake passage. The present applicant has already proposed an internal combustion engine equipped with an intake control valve that responds to conditions (for example, Japanese Patent Application No. 153382/1982). In this internal combustion engine, for example, by closing the intake control valve during partial load operation, the intake air is allowed to flow into the combustion chamber at high velocity only from the first intake passage, creating strong turbulence within the combustion chamber. During load operation, the intake control valve is fully opened to allow intake air to flow into the combustion chamber from both the first intake passage and the second intake passage, thereby achieving high charging efficiency. However, in this internal combustion engine, the fuel injection valve is arranged on the extension line of the partition wall, and the fuel injected from the fuel injection valve is divided into two equally by the upstream end of the partition wall, and is sent to the first intake passage and the second intake passage, respectively. Can be sorted. If the fuel is evenly distributed in this way when the intake control valve is open, the air-fuel mixture of approximately the same concentration is supplied into the combustion chamber from the first intake passage and the second intake passage, resulting in good combustion. can be obtained. However, when the intake control valve is closed, if the fuel is distributed equally to the first intake passage and the second intake passage, the fuel distributed and supplied to the first intake passage will become attached to the intake control portion. This causes a problem in that good acceleration cannot be achieved because all of the injected fuel is not immediately supplied into the fuel chamber.
Furthermore, if an attempt is made to generate a swirling flow in the combustion chamber and inject fuel from the fuel injection valve into the intake port during the latter half of the intake stroke, thereby stratifying the air-fuel mixture in the combustion chamber and combusting a lean air-fuel mixture. As mentioned above, if a large amount of fuel adheres to the intake control valve, a problem arises in that good stratification cannot be achieved.

The present invention can ensure good combustion when the intake control valve is open, and good acceleration operation when the intake control valve is closed, and can also ensure reliable combustion of a lean mixture due to good stratification. An object of the present invention is to provide a fuel injection type internal combustion engine.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 and 2, 1 is a cylinder block, 2 is a piston, 3 is a cylinder head, 4 is a combustion chamber, 5 is a first intake valve, 6 is a second intake valve, and 7 and 8 are exhaust valves. , 9 is a spark plug, 10 is an intake manifold or surge tank branch pipe, and the intake manifold 10 is fixed to the cylinder head 3 via a spacer 11. The cylinder head 3, spacer 11 and intake manifold 10 have a bulkhead 1 inside.
2, a first intake passage 13 and a second intake passage 14 are formed. The first intake passage 13 and the second intake passage 14 extend parallel to each other and are connected into the fuel chamber 4 via the first intake valve 5 and the second intake valve 6, respectively. A communication hole 15 is formed on the partition wall 12, and the communication hole 15 connects the first intake passage 13 and the second intake passage 1.
4 can be made to communicate with each other. As shown in FIG. 1, a fuel injection valve 16 is disposed within the first intake passage 13, and fuel is injected from the fuel injection valve 16 over a range of angle θ. Further, a first intake control valve 17 is provided in the second intake passage 14 upstream of the communication hole 15.
is arranged downstream of the communication hole 15 and the second intake passage 14.
A second intake control valve 18 is disposed therein.

During engine high speed and high load operation, the first intake control valve 17
Both the second intake control valve 18 and the second intake control valve 18 are fully opened, and thus high filling efficiency can be obtained at this time. The first intake control valve 17 is closed during high-load and medium-low speed engine operation, and thus the first intake passage 13
Air flowing therein is divided at the communication hole 15 and supplied into the combustion chamber 4 via the first intake valve 5 and the second intake valve 6. At this time, since the intake air flows at a high speed in the first intake passage 13 in the intake manifold 10, the inertia of the intake air becomes large, and then flows into the combustion chamber 4 with this large inertia, resulting in high charging efficiency. can get. During partial load operation, the first intake control valve 18 is closed, so that at this time intake air is supplied into the combustion chamber 4 only via the first intake valve 5. As a result, the intake air flows into the combustion chamber 4 at a high speed, so that strong turbulence can be generated within the fuel chamber 4.

As described above, fuel is injected from the fuel injection valve 16 over the angle θ, and most of this injected fuel is supplied into the first intake passage 13, and the remaining small amount of injected fuel is injected through the communication hole 15. A fuel injection valve 16 is arranged so as to be supplied into the second intake passage 14 . That is, if the distance between the axis of the partition wall 12 and the axis of the fuel injection valve 16 is a, and the distance from the nozzle port 19 to the upstream end 20 of the partition wall 12 in FIG. 2 is l, then 0<a<l・tanθ/2. The fuel injection valve 16 is arranged within the range a.

Now, when all the fuel injected from the fuel injection valve 16 is supplied into the first intake passage 13, that is, when a>ltanθ/2, the second intake control valve 18 is closed. Since the injected fuel does not adhere to the second intake control valve 18 during this period, a good transient response P can be obtained as shown in the range a>ltanθ/2 in FIG. However, in this case, if the second intake control valve 18 is open, the rich air-fuel mixture is supplied into the combustion chamber 4 via the first intake valve 5, and the second intake valve 6
Since only air is supplied through the fuel tank, the fuel is not mixed sufficiently. At this time, the combustion quality Q deteriorates as shown in the range a>ltanθ/2 in FIG. On the other hand, when the fuel injection valve 16 is provided on the axis of the partition wall 12 and the fuel is evenly distributed to the first intake passage 13 and the second intake passage 14, that is, when a=0, the second intake control valve When valve 18 is open, good fuel Q can be obtained as shown in FIG. However, when the second intake control valve 18 is closed, the transient response P deteriorates as shown in FIG. 3. There is an optimal value of a that satisfies both transient response P and combustion Q to some extent, and this value of a is 0.
It is clear that the range satisfies <a<ltanθ/2. Therefore, in the fuel injection valve 16, a large amount of fuel is supplied into the first intake passage 13, and a small amount of fuel is supplied into the second intake passage 13.
The fuel is arranged so as to be supplied into the intake passage 14, and in this case, both the transient response P and the combustion Q can be satisfied to some extent.

Figures 5 and 6 show another example. In this example, the intake passage 30 is separated into a first intake passage 32 and a second intake passage 33 by a partition wall 31 near the first intake valve 5 and the second intake valve 6,
An intake control valve 34 is inserted into the second intake passage 33. This intake control valve 34 is closed when the engine is operating at low speed, and opened when the engine is operating at high speed. In this embodiment as well, if a, l, and θ are defined in the same way as in FIG. 1, the fuel injection valve 16 is arranged in the range of 0<a<ltanθ/2.

FIGS. 7 and 8 show yet another embodiment. In this embodiment, one intake valve 4 is provided in the fuel chamber 4.
Zero and one exhaust valves 41 are provided. A partition wall 43 protrudes from the upper wall surface of the intake boat 42 into the intake boat 42, and the partition wall 43 separates the intake boat 42 into a helical first intake passage 44 and a bypass second intake passage 45. Second intake passage 4
An intake control valve 46 is disposed within 5. This intake control valve 46 is closed when the engine is operating at low speed, and opened when the engine is operating at high speed. When the intake control valve 46 is closed, most of the intake air is supplied into the combustion chamber 4 through the large helical intake passage 44, so that a strong swirling flow is generated within the combustion chamber 4. It will be done. In this embodiment as well, if a, l, and θ are defined in the same way as in FIG.
<ltanθ/2.

As described above, according to the present invention, the fuel injection valve is arranged so that a large amount of fuel can be supplied into the first intake passage and a small amount of fuel can be supplied into the second intake passage provided with the intake control valve. Therefore, when the intake control valve is closed, fuel is prevented from adhering to the intake control valve and the inner wall surface of the second intake passage around the intake control valve, thereby achieving good acceleration operation. Furthermore, if a swirling flow is generated in the combustion chamber and the fuel is injected in the latter half of the intake stroke, good stratification can be obtained in the combustion chamber, and stable combustion with a lean mixture can thus be obtained. can. Further, when the intake control valve is opened, good fuel can be obtained as in the conventional case.

[Brief explanation of the drawing]

FIG. 1 is a plan sectional view of an internal combustion engine according to the present invention;
Fig. 2 is a side sectional view of Fig. 1, Fig. 3 is a diagram showing the quality of transient response on the vertical axis P, and Fig. 4 is a graph showing the quality of combustion, that is, the quality of exhaust emissions, on the vertical axis Q.
5 is a plan sectional view of another embodiment, FIG. 6 is a side sectional view of FIG. 5, FIG. 7 is a plan sectional view of yet another embodiment, and FIG. 8 is a plan sectional view of another embodiment. FIG. 7 is a side sectional view of FIG. 7; 5, 6, 40... Intake valve, 7, 8, 41... Exhaust valve, 12, 31, 43... Partition wall, 13, 32,
44...First intake passage, 14,33,45...Second intake passage, 16...Fuel injection valve, 17,18,
34, 46... Intake control valve.

Claims (1)

[Claims] 1. A fuel injection valve is provided in the intake passage, and the intake passage downstream of the fuel injection valve is divided into two into a first intake passage and a second intake passage by a partition wall extending along the axis of the intake passage, and a fuel injection valve is provided in the second intake passage. In a fuel injection type internal combustion engine, an intake control valve is provided in the fuel injection type internal combustion engine, and the intake control valve is opened and closed depending on the engine operating state, and the upstream end of the partition wall is located within the fuel injection area of the fuel injection valve. A fuel injection type internal combustion engine, further comprising a fuel injection valve arranged such that the amount of fuel supplied into the first intake passage is greater than the amount of fuel supplied into the second intake passage.