JPH0463227B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an intake manifold for a multi-cylinder gasoline engine, and is particularly suitable for improving the distribution of fuel between cylinders of a fuel injection device that injects fuel into a gathering part of an intake passage. related to intake manifolds for gasoline engines.

[Conventional technology]

Conventionally, as a method to improve fuel distribution in multi-cylinder gasoline engines, there was a method shown in Japanese Utility Model Publication No. 56-66054, in which a cylindrical heating element was installed downstream of the throttle valve of the carburetor to evaporate the fuel adhering to the wall surface. It was known.

[Problem that the invention seeks to solve]

However, this method has problems such as the expensive heating element and the need for a large-capacity generator because it uses a large amount of electricity, making it difficult to use in vehicles.

SUMMARY OF THE INVENTION An object of the present invention is to provide an intake manifold for a multi-cylinder gasoline engine with good fuel distribution between cylinders.

[Means for solving problems]

A feature of the present invention is that an inner cylinder is provided upstream of the branch part of the intake passage to reduce the amount of fuel flowing unevenly into each cylinder along the wall surface of the branch part of the intake passage, and the inner cylinder and the intake passage are communicated with each other. This is achieved by providing a communicating hole.

[Effect]

The fuel adhering to the intake passage flows along the inner wall of the inner cylinder, and is atomized at the downstream end of the inner cylinder by the air flow flowing on the inner and outer surfaces of the inner cylinder. Furthermore, by utilizing the phase difference between the intake air of each cylinder, it is possible to improve the distribution performance of the air flow flowing on the outer surface of the inner cylinder simply by using a communication hole that communicates the gap between the intake passage and the inner cylinder.

[Embodiments of the invention]

An embodiment in which the present invention is applied to a six-cylinder gasoline engine will be described below with reference to FIGS. 1, 2, and 3.

Figures 1 and 2 show the structure of the intake manifold and cylinder arrangement of this embodiment. The cylinder arrangement of the engine 1 is such that the first, third, and fifth cylinders are provided on one side of the intake manifold 2, and the second, fourth, and sixth cylinders are provided on the opposite side. The intake passage 3 that connects to the first, third, and fifth cylinders is separated at a branch part 5 immediately below the vertical shaft A4 that forms part of the intake passage 3, and is connected to each cylinder. Similarly, the intake passage 6 connected to the second, fourth, and sixth cylinders is the intake passage 6.
It is divided at a branch part 8 just below the shaft B7, which forms part of the shaft, and is connected to each cylinder. Vertical shaft A4
The vertical shaft B7 communicates with the shaft B7 through a communication hole 9.

The intake passage 3 upstream of the shaft A4 communicates with a space 12 in an injection body 11 fixed to the intake manifold 2 via a spacer 10. In the space 12, fuel supply sections 15 and 16 including fuel injection valves 13 and 14 are arranged. In the intake passage 3 between the fuel supply section 15 and the shaft A4, there is provided an inner cylinder 18 that is attached to a throttle valve 17 and a spacer 10 and projects into the shaft A4. A ring-shaped gap 20 is provided between the outer wall of the inner cylinder 18 and the inner wall 19 of the intake passage made up of the inner wall of the vertical shaft A. Similarly, the air intake path 6 also has space 1.
2, and between the fuel supply section 16 and the vertical hole B7 there is a throttle valve 21, an inner cylinder 22, an inner wall 23 of the intake passage, and a gap 2.
4 is provided.

The upstream ends of the gaps 20 and 24 are closed by the spacer 10, and the downstream ends are open toward the intake passages 4 and 6, respectively. The downstream ends of the inner cylinders 18, 22 do not increase the flow path resistance in the branching parts 5, 6, so that the downstream ends of the inner cylinders 18, 22 reach almost the lower ends of the shafts A, B, 4, 7 or the shafts A, B,
It is set in the middle of 4 and 7. The opening position of the communication hole 9 is provided upstream from the lower ends of the inner cylinders 18 and 22.

Therefore, the intake passages 3 and 6 form independent intake passages downstream of the space 12. Fuel supply part 1
5 and 16 are arranged so that the most upstream positions of fuel adhesion parts 26 and 27, where the discharged fuel adheres to the wall surface, are downstream from the connection point of the intake passages 3 and 6 with the space 12, respectively.

Space 12 communicates with the atmosphere via an air flow meter and an air cleaner (not shown).

Most of the fuel injected from the fuel supply section 16 in synchronization with the intake air flow is atomized, passes through both sides of the throttle valve 17, reaches the branch passage 5, and then travels along the intake passage into the first, third, and fifth branches. It flows into one of the cylinders that is on the intake stroke. On the other hand, some of the fuel adheres to the wall surface of the intake passage 3 and flows, reaching the lower end of the inner cylinder 18 . On the other hand, if the firing order of each intake cylinder is 1, 2, 3, 4, 5, 6, the intake timing will be as shown in FIG. (The numbers surrounded by circles in the figure indicate the numbers of each cylinder during intake.) Therefore, when the intake speed of the first cylinder is the highest, none of the cylinders on the intake path 6 side is in the intake stroke. Therefore, at this time, as shown by the arrow in FIG. 3, an air flow from the intake passage 6 toward the intake passage 3 is generated within the communication hole 9. This airflow flows within the gap 20 on the outer surface of the inner cylinder 18, blows off the fuel adhering to the lower end of the inner cylinder 18 together with the airflow inside the inner cylinder 18, and causes it to flow into the first cylinder from the branch portion 5.

Therefore, this occurs when the inner cylinder 18 is not present. Since the fuel adhering to the inner wall of the intake passage 3 flows along the wall surface without riding along with the airflow, there is a tendency for the fuel to flow into any one cylinder easily, and even if there is an inner cylinder 18, there is no air on the outer wall surface of the inner cylinder. Therefore, the disadvantage that the fuel caught in the air gap 20 flows into the cylinders along the wall surface of the intake passage can be prevented, and the distribution of fuel to each cylinder can be made more uniform.

In general, the distribution of fuel between cylinders is particularly poor when the fuel is operated at low speeds and the throttle valve is fully open.
When the present invention is applied to a fuel injection device that injects fuel into the gathering part of the intake passage in synchronization with the intake air as in this embodiment, when the fuel is fully opened at low speed, the fuel injection time is shorter than the intake stroke. The air flowing in from the side intake passage contains almost no fuel, and exhibits ideal effects. When fuel continuously flows in from a fuel supply section, such as in a carburetor, some fuel is mixed into the air flow passing through the communication hole 9, so the effect is reduced to some extent, but it is not impossible to use.

The inner walls 18 and 22 are desirably made of fluoride or ethylene resin to which fuel does not easily adhere, or the metal surface is coated with the same resin.

FIG. 4 shows another embodiment of the invention.

The downstream ends of the inner cylinders 18 and 22 are connected to the intake passage inner wall 19,
By narrowing the exits of the gaps 20 and 24, air passing through the communication hole 9 and flowing on the outer surfaces of the inner cylinders 18 and 22 has the effect of uniformly flowing around the outer circumferences of the inner cylinders 18 and 22.

Further, although the communication hole 9 is provided on the lower surface of the spacer 10 instead of the intake manifold 2, the effect is the same as if it were provided on the intake manifold 2.

Furthermore, an auxiliary passage 25 that recirculates exhaust gas to the intake passage in order to reduce _NOx in the exhaust gas and introduces air, etc. to the intake passage that bypasses the throttle valves 17 and 21 to increase the idle speed at low temperatures. By opening into the communication hole 9, the exhaust gas flow and the air flow flowing through the intake passage 36 are biased to one side of the intake passage, thereby preventing uneven distribution of fuel and air to each cylinder. It has the effect of preventing

Furthermore, due to the difference in the distance between the branch parts 5 and 8 and the fuel supply parts 15 and 16 due to the arrangement of the intake passages, the difference in the amount of fuel that adheres to the wall surface before reaching the branch part occurs. The difference in fuel distribution between the two intake passages 3 and 6 can be made by making the distances between the branch parts 5 and 8 and the lower ends of the inner cylinders 18 and 22 almost the same.
This can be prevented by making the amount of atomized fuel attached to the branch wall surface uniform at the lower end of No. 2.

Note that the present invention is effective not only for the V-type six-cylinder engine shown in the embodiment, but also for four-, six-, and eight-cylinder engines having two independent intake passages, regardless of the cylinder arrangement.

〔Effect of the invention〕

Therefore, according to the present invention, it is possible to improve the uneven distribution of fuel between the cylinders of a multi-cylinder gasoline engine with an inexpensive method that involves simply adding simple passages and cylindrical parts, and the output of the engine can be improved. It has the effect of improving fuel efficiency.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention;
2 is a top view showing the cylinder and intake manifold arrangement of the embodiment of FIG. 1, FIG. 3 is a schematic diagram showing the intake timing of the embodiment of FIG. 1, and FIG. 4 is another embodiment. FIG. 1... Engine, 2... Intake manifold, 3...
Intake path, 4... Vertical shaft A, 5... Branch, 6... Intake path, 7... Vertical shaft B, 8... Branch, 9... Communication hole, 10... Spacer, 11... Indicator Excision body, 12...Space, 13...Fuel injection valve,
14...Fuel injection valve, 15...Fuel supply section, 16
... Fuel supply section, 17 ... Throttle valve, 18 ... Inner cylinder, 19 ... Intake path inner wall, 20 ... Gap, 21 ...
... Throttle valve, 22 Inner cylinder, 23 ... Intake path inner wall, 24
... air gap, 25 ... auxiliary passage, 26 ... fuel adhesion section, 27 ... fuel adhesion section.

Claims (1)

[Scope of Claims] 1. A multi-purpose intake manifold in which the intake flow path is composed of a plurality of independent intake paths from upstream of the fuel injection part or the fuel adhesion part to the inner wall of the intake passage downstream of the fuel injection part to each cylinder. In the cylinder gasoline engine, the intake passage is arranged upstream of a branch part of the intake passage downstream of the fuel injection part or the fuel adhesion part of each of the intake passage so as to form a cylindrical gap with the inner wall of the intake passage. An inner cylinder and a communication hole opened on the upstream side of the cylindrical gap are provided, the upstream end of the cylindrical gap is closed, the downstream end is open to the intake passage, and the communication holes are communicated with each other. This is an intake manifold for a gasoline engine. 2. The intake manifold for a gasoline engine according to claim 1, characterized in that a reinforcing passage is opened in the communication hole.