JPS6313425Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an intake negative pressure extraction structure for an engine that takes out intake negative pressure for operating negative pressure operating equipment.

(Prior art) Conventionally, in an engine, a negative pressure outlet has been provided in the intake manifold, as shown in Japanese Utility Model Application Publication No. 55-36998, in order to operate various negative pressure operating devices using the negative intake pressure. This is known.

However, in such a conventional structure, an enlarged chamber is provided for each negative pressure outlet in order to alleviate intake pulsation, and there is a problem in that the number of parts increases. Further, such a negative pressure outlet is provided at a gathering part of the intake manifold or near an intake port of the intake manifold. However, in the former case, since the fuel tank is located near the carburetor, there is a risk that a portion of the fuel may flow in and damage the negative pressure operating equipment. For example, if the negative pressure operating device is a diaphragm device, the diaphragm absorbs fuel and swells, leading to early failure. On the other hand, in the latter case, since it is located near the combustion chamber, it is affected by the pulsation caused by the opening and closing of the intake valve, and there is also the risk of clogging with carbon generated in the backup fire.

In addition, when recirculating exhaust gas, the exhaust recirculation gas needs to be uniformly supplied to each cylinder, so the exhaust recirculation passage should be connected as far upstream as possible from the intake passage, but the negative pressure outlet should be connected to the throttle. The exhaust recirculation passage must be placed downstream of the valve, and due to space constraints, the exhaust gas recirculation passage must be placed in the intake passage upstream of the negative pressure outlet due to the integrated structure with the intake manifold to facilitate the formation of the negative pressure outlet. There are cases where it is connected.

In such a case, carbon in the reflux gas enters the negative pressure outlet and the passage leading thereto, causing a problem of increased passage resistance due to adhesion and accumulation of carbon.

(Purpose of the invention) The present invention has been made in view of the above points, and has a simple structure without unnecessarily increasing the number of parts. It is an object of the present invention to provide an intake negative pressure extraction structure for an engine that can simultaneously prevent an increase in passage resistance due to accumulation and an inflow of fuel, thereby preventing malfunction of negative pressure operating equipment.

(Structure of the invention) The present invention includes an enlarged chamber that communicates with the intake passage downstream of the throttle valve and downstream of an opening in the exhaust gas recirculation passage that supplies part of the exhaust gas to the intake passage; In order to achieve the above object, fuel is supplied to the intake passage upstream of the enlarged chamber, and the intake passage is connected to the enlarged chamber. The present invention is characterized in that a labyrinth section is provided between the fuel passage and the passage, and a fuel return passage is provided at the bottom of the labyrinth section for returning the fuel separated in the labyrinth section to the intake passage.

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

In Figures 1 to 3, 1 is a four-cylinder engine, 2 is an intake manifold, 3 is a carburetor that supplies fuel, and 4 is a throttle valve that supplies fuel to an intake passage 5 upstream of the throttle valve 4. supply. 6 is an air cleaner.

An enlarged chamber 7 communicating with the intake passage 5 is provided in the intake passage 5 (intake manifold 2) downstream of the throttle valve 4, and an intake air temperature control diaphragm device 8 as a negative pressure operating device is provided in the enlarged chamber 7.
Negative pressure outlets 10 and 11 to which the vacuum controller 9 is linked are also provided.

A mounting member 12 is attached to the intake manifold 2, and an exhaust gas recirculation passage 13 (hereinafter referred to as an EGR passage) is formed inside. EGR passage 13 is
The upstream end 13a is an opening 14 through which part of the exhaust gas, that is, the recirculation gas, is taken out from the exhaust passage (not shown).
The downstream end 13b is connected to another opening 15 for supplying the recirculation gas to the upstream side of the enlarged chamber 7 of the intake passage 5, and an exhaust recirculation valve 16 is connected in the middle thereof.
(hereinafter referred to as the EGR valve) is installed. this
In the EGR valve 16, a casing 16a is defined by a diaphragm 16b into a first chamber 16c and a second chamber 16d, and a valve body 16e is connected to the diaphragm 16b. As a result, the valve body 16e
However, by introducing negative pressure into the first chamber 16c through the negative pressure intake port 16f, the opening 17a of the shielding plate 17 provided in the middle of the EGR passage 12 is opened to perform exhaust gas recirculation.

The enlarged chamber 7 has an inlet portion communicating with the intake passage 5 that is narrowed by the interior wall 18 so that the recirculated gas from the exhaust gas recirculation passage 13 does not flow in, and there is a fuel separation valve between the enlarged chamber 7 and the intake passage 5. For this purpose, upper and lower baffle plates 19 and 20 are provided as a labyrinth part, and the separated fuel is returned to the intake passage 5 through the through hole 20a (fuel return passage) of the lower buffle plate 20, which is the bottom of the labyrinth part. It's getting old. In addition, the effect of canceling out pulsation is enhanced by both buff-full plates 19 and 20.

With the above configuration, fuel is supplied through the intake passage 5 upstream of the expansion chamber 7, but even if the fuel is introduced into the expansion chamber 7 together with the intake air, it will not collide with both bumpy plates 19, 20. The air is separated from the intake air and returned to the intake passage 5 along the inner wall surface through the through hole 20a of the lower buffle plate 20. Therefore, fuel does not flow into the diaphragm device 8 and the vacuum controller 9, which are negative pressure operating devices, and their operations are performed reliably.
In addition, since negative pressure is supplied from the intake passage 5 through the labyrinth section made up of the baffle plates 19 and 20 and the expansion chamber 7, the synergistic effect of the buffle plates 19 and 20 and the expansion chamber 7 alleviates the intake pulsation. Stable negative pressure is extracted.

Furthermore, the intake passage 5 passes through the exhaust gas recirculation passage 15.
Even if carbon in the exhaust gas recirculated to the expansion chamber 7 attempts to enter the expansion chamber 7, the invasion is blocked by the labyrinth parts of the baffle plates 19 and 20, together with the fuel that attempts to enter the expansion chamber 7. The carbon is returned to the intake passage 5 along with the fuel through the through hole 20a (fuel return passage) of the side buffle plate 20.

(Effects of the invention) Since the present invention is constructed as described above, it has a simple structure without unnecessarily increasing the number of parts, and can apply negative pressure to negative pressure operating equipment without being affected by intake pulsation. It can be taken out and also
It is possible to prevent carbon in the reflux gas from adhering to the expansion chamber and fuel from flowing into the expansion chamber, thereby preventing malfunction of each negative pressure operating device due to these.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a plan view of the vicinity of the intake negative pressure extraction part of the engine, FIG. 2 is a view taken along the - line in FIG. 1, and FIG. - is a sectional view taken along the line. 1...Engine, 4...Throttle valve, 5
... Intake passage, 7... Expansion chamber, 10, 11... Negative pressure outlet, 13... Exhaust recirculation passage, 19, 20...
... Boundful plate, 20a... Through hole.

Claims (1)

[Scope of utility model registration request] An enlarged chamber communicating with the intake passage downstream of the throttle valve and downstream of the opening in the exhaust gas recirculation passage that supplies part of the exhaust gas to the intake passage; and a negative pressure outlet connected to the enlarged chamber with a negative pressure operating device. In the intake negative pressure extraction structure for an engine, the fuel is supplied to the intake passage upstream of the enlarged chamber, and a labyrinth part is provided between the enlarged chamber and the intake passage, and a labyrinth part is provided at the bottom of the labyrinth part to separate the fuel from the intake passage. An intake negative pressure extraction structure for an engine, characterized in that a fuel return passage is provided for returning the absorbed fuel to the intake passage.