JPH05332226A - Intake air manifold of internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the distribution characteristics of bypass air by a method wherein a bypass groove part with a specified size communicated with a bypass passage running around a throttle valve is formed in at least one of the joint on the body side of a throttle body and the joint on the manifold side of an intake air manifold. CONSTITUTION:A bypass groove 204 is formed in one, for example, a joint 134a on the manifold side, of joints 132a and 134a so that a portion situated downstream of a bypass passage is produced between connection surfaces during joining of the joint 132a on the body side of a throttle body 132 and the joint 134a on the manifold side of an intake air manifold 134. The bypass groove 204 is formed such that the width thereof is set to a value higher than the height H of the bypass groove part 204 being the portion situated downstream of the bypass passage. This constitution causes uniform mixture of fuel and bypass air and uniformizes mixture nature. The bypass passage comprises a bypass passage 174 for idle regulation and a bypass passage 176 for first idle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake manifold of an internal combustion engine, and more particularly, to improving the homogeneity of the air-fuel mixture in the warm-up process at the time of cold start of the internal-combustion engine and achieving uniformization of the air-fuel mixture. And an intake manifold for an internal combustion engine that can prevent variations in engine speed during warm-up operation and prevent spark plug smoldering and smoldering. ..

[0002]

2. Description of the Related Art Some internal combustion engines mounted on vehicles have a single fuel injection valve (single-point injection type fuel injection valve) in an intake passage upstream of a throttle valve. Further, some internal combustion engines are equipped with an air-fuel ratio control device as a countermeasure for problems such as exhaust harmful components and fuel consumption rate. The air-fuel ratio control device electrically detects the operating state of the internal combustion engine, such as exhaust oxygen concentration, engine speed, engine load, intake air amount, intake pressure, intake temperature, and the amount of fuel injected and supplied by the fuel injection valve. And the bypass passage increase or decrease the amount of bypass air introduced into the intake passage on the downstream side of the throttle valve to control the air-fuel ratio to a target value.

Further, as an intake device for an internal combustion engine, as disclosed in Japanese Utility Model Laid-Open No. 52-170114, an intake port of the engine is connected to the intake manifold while a groove for accumulating liquid fuel is provided on the inner surface of the intake manifold. Some of them have a guide part for guiding the liquid fuel to a position closest to the sub chamber or the spark plug in the combustion chamber side opening of the intake port and directing the liquid fuel to the sub chamber or the spark plug.

Further, an internal combustion engine having a bypass passage is shown in FIG. In FIG. 7, 2 is an internal combustion engine equipped with an air-fuel ratio control device, 4 is a cylinder block,
6 is a cylinder head, 8 a cylinder head cover, 10 is a valve operating mechanism, 12 is a cylinder, 14 is a piston, 16 is a combustion chamber, 18 is an intake port, 20 is an exhaust port, 22 is an intake valve, and 24 is an exhaust valve. The internal combustion engine 2 includes an intake pipe 26, an air cleaner 28, an intake hose 30, a throttle body 32, and an intake manifold 3 which form an intake system.
4 and 4 are sequentially connected. Further, to the internal combustion engine 2, an exhaust manifold 36 forming an exhaust system and an exhaust pipe (not shown) are sequentially connected.

The intake pipe 26, the air cleaner 28, the intake hose 30, the throttle body 32, and the intake manifold 34 respectively include a pipe inlet 38, a pipe intake passage 40, a cleaner intake chamber 42, a hose intake passage 44, and a body intake passage 46. And a manifold intake passage 48 are sequentially provided to communicate with each other, and are connected to the intake port 18. A throttle valve 50 is provided in the body intake passage 46. The exhaust manifold 36 and an exhaust pipe (not shown) are provided with a manifold exhaust passage 52 communicating with the exhaust port 20 and a pipe exhaust passage (not shown) communicating with the outside.

Reference numeral 54 is an O ₂ sensor. O
_{The 2} sensor 54 is connected to a control unit of an air-fuel ratio control device (not shown). The control unit inputs the detection signal of the O ₂ sensor 54 and increases or decreases the fuel amount or the bypass air amount to control the air-fuel ratio to a target value.

The internal combustion engine 2 has a throttle valve 50.
A single fuel injection valve 56 is provided in the upstream body intake passage 46. The fuel injection valve 56 is connected to a fuel pump 62 in a fuel tank 60 via a fuel supply passage 58. A fuel filter 64 is provided in the middle of the fuel supply passage 58.

Further, the fuel injection valve 56 is provided in the fuel introduction passage 6
6 to a fuel pressure regulator 68.
The fuel pressure regulator 68 is operated by the intake pipe pressure from the fuel pressure adjusting pressure passage 70 communicating with the manifold intake passage 48 on the downstream side of the throttle valve 50, and adjusts the fuel pressure acting on the fuel injection valve 56 to a predetermined value. The fuel pressure regulator 68 is connected to the fuel tank 60 through the return fuel passage 72.

The internal combustion engine 2 has a throttle valve 50.
As a bypass passage for introducing the bypass air into the downstream manifold intake passage 48, an idle adjustment bypass passage 74, a fast idle bypass passage 76, and an idle speed control bypass passage 78 are provided. In the middle of each of the bypass passages 74 to 78, an idle adjusting screw 80, a fast idle adjusting valve 82, and an idle speed control valve 84 are provided as bypass air amount adjusting means.

The idle adjusting bypass passage 74 and the fast idle bypass passage 76 are brought into communication by gathering at an inlet 86 of the bypass passage provided with the upstream side facing the body intake passage 46 on the upstream side of the throttle valve 50. Then, the midstream portions are separated and provided in parallel, and the downstream side of the manifold intake passage 4 on the downstream side of the throttle valve 50.
8 and the outlets 88 of the bypass passages facing each other are gathered and communicated.

The idle speed control bypass passage 78 has a throttle valve 50 on the upstream side.
The throttle valve 5 is connected to the inlet 90 of a bypass passage provided facing the cleaner intake chamber 42 on the upstream side and the downstream side is connected to the throttle valve 5.
The outlet 88 provided so as to face the manifold intake passage 48 on the downstream side is collectively communicated with the idle adjusting bypass passage 74 and the fast idle bypass passage 76.

The idle adjusting screw 80 is used for the internal combustion engine 2
It is rotated to adjust the bypass air when setting the idle speed of the. The fast idle adjustment valve 82 is opened and closed to supply bypass air when the internal combustion engine 2 is cold.
The idle speed control valve 84 is connected to a control unit (not shown) and is controlled to be opened and closed so that the idle speed becomes the target idle speed during idle operation.

As a result, when the internal combustion engine 2 is cooled, the air taken in from the pipe inlet 38 is supplied to the idle adjusting bypass passage 74, the first idle bypass passage 76, and the idle speed control bypass passage 7.
8 and is introduced as bypass air and supplied to the combustion chamber 16.

[0014]

During the warm-up process when the internal combustion engine 2 is cold-started, the throttle valve 50 moves to the position shown in FIG.
As shown in, it is in a substantially closed state. As a result, the fuel injected and supplied from the fuel injection valve 56 is discharged from the gap between the valve end 50e of the throttle valve 50 and the body intake passage 46.
It will flow into the manifold intake passage 48 without being atomized. This fuel is dispersed in particles by the bypass air introduced from the outlet 88. The degree / state of the fuel dispersion determines the distribution performance to each combustion chamber 16. Therefore, if the degree or state of fuel dispersion deteriorates, the distribution performance deteriorates.

However, each bypass passage 74, 76, 7
The outlet 88 of No. 8 was oriented toward the center C of the manifold intake passage 48, and was formed so as to have a perfect circular cross section with a constant cross-sectional area (diameter φ: D) from the upstream portion to the downstream portion. From the downstream part of the manifold intake passage 48
By-pass air introduced into the unit has a constant cross-sectional area (diameter φ:
There is a problem that only a part of the fuel facing the downstream portion of D) is contacted, and most of the fuel is not contacted.

For this reason, the bypass air is mixed with the fuel unevenly, the property of the air-fuel mixture deteriorates and becomes non-uniform, the distribution performance of the air-fuel mixture deteriorates, and combustion becomes unstable. There was an inconvenience. Further, there is a problem that the engine speed varies when the internal combustion engine is warmed up, and there is a problem that the spark plug is fogged or smoldered.

[0017]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention bypasses a throttle valve provided in the middle of the intake passage and introduces bypass air into the intake passage downstream of the throttle valve. In an internal combustion engine in which a bypass passage is provided and a bypass air amount adjusting means is provided in the middle of the bypass passage, a connecting surface at the time of joining the body-side joining surface of the throttle body having the throttle valve built therein and the manifold-side joining surface of the intake manifold. At least one of the body-side joint surface and the manifold-side joint surface is provided with a bypass groove portion in which the width of the bypass passage is formed larger than the height of the bypass passage in order to expose the downstream side portion of the bypass passage. Is characterized by.

[0018]

According to the invention as described above, when the internal combustion engine is operated, the air and fuel are supplied from the upstream side of the throttle valve in the intake passage, and the amount of the air and fuel is adjusted by the throttle valve and then the downstream of the intake passage. Side internal combustion engine.

Further, under a predetermined condition of the internal combustion engine, the air on the upstream side of the bypass passage is supplied to the intake passage on the downstream side of the throttle valve after being adjusted by the bypass air amount adjusting means.

At this time, since the width of the bypass groove portion, which is the downstream side portion of the bypass passage, is formed larger than the height of the bypass passage, the contact area of the bypass air with the fuel and the air is increased in the intake passage. ing.

[0021]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 4 show an embodiment of the present invention. In FIG. 2, 132 is a throttle body, 1
Reference numeral 34 is an intake manifold. This throttle body 1
32, a body intake passage 146 is provided, and the throttle valve 1 is provided in the middle of the body intake passage 146.
50 are provided. A manifold intake passage 148 is formed in the intake manifold 134.

In order to expose the downstream side portion of the bypass passage 202 between the connecting surfaces when the body side joint surface 132a of the throttle body 132 in which the throttle valve 150 is installed and the manifold side joint surface 134a of the intake manifold 134 are joined. At least one of the body-side joint surface 132a and the manifold-side joint surface 134a, for example, the manifold-side joint surface 134a, has a width L of the bypass groove portion 204 which is a downstream side portion of the bypass passage 202 at a downstream side portion of the bypass passage 202. Height H of certain bypass groove portion 204
The bypass groove portion 204 formed larger than the above is provided.

More specifically, the bypass passage 202 is
It has an idle adjusting bypass passage 174 formed in the throttle body 132, a fast idle bypass passage 176, and a bypass groove portion 204 formed in the intake manifold 134.

The idle adjusting bypass passage 174 and the fast idle bypass passage 176 have a starting end opening at the same portion on the upstream side of the throttle valve 150 and an end opening at the same portion on the body side joint surface 132a. .. In the middle of the idle adjusting bypass passage 174, an idle adjusting screw 180 which is one bypass air amount adjusting means is arranged, and a fast idle adjusting valve 182 is arranged in the first idle bypass passage 176. Has been done.

Further, the bypass groove portion 204 is directed toward the center C of the manifold intake passage 148 so that the height H of the bypass groove portion 204 is 3.5 〓 or less and the width L of the bypass groove portion 204 is 14 or less. It is formed by denting so as to have a rectangular cross-section with a constant cross-sectional area so as to be 〓 or less.

In this way, the bypass groove portion 204 is recessed in the manifold-side joint surface 134a so as to be oriented toward the center C of the manifold intake passage 148 so as to have a rectangular cross section with a constant cross-sectional area of height: H and width: L. It is formed straight.

Next, the operation will be described.

When the internal combustion engine 2 is operated, air and fuel are supplied from the upstream side of the throttle valve 150 of the body intake passage 146, and after being metered by the throttle valve 150, the downstream side of the body intake passage 146. Is supplied to the internal combustion engine 2 via the manifold intake passage 152.

When the internal combustion engine 2 is idle at a predetermined condition, the air upstream of the throttle valve 150 serves as the bypass passage 202, ie, the idle adjusting bypass passage 174 and the fast idle bypass passage 176.
The idle adjusting screw 180 and the fast idle adjusting valve 182 are metered respectively and then supplied to the manifold intake passage 152 on the downstream side of the throttle valve 150.

At this time, since the width L of the bypass groove portion 204, which is the downstream side portion of the bypass passage 202, is formed larger than the height H of the bypass groove portion 204, even if the cross-sectional area is the same, the conventional diameter can be used. The width L of the bypass groove portion 204 can be made larger (D <L) than that of the outlet of φ: D, the contact area between the bypass air and the fuel can be increased, and the fuel and the air of the bypass air in the manifold intake passage 152 can be increased. The contact area with is expanding.

With this, the contact area between the bypass air and the fuel can be increased without decreasing the flow velocity of the bypass air, the bypass air can be mixed with most of the fuel, and the bypass can be mixed with the fuel. The air can be mixed evenly.

Therefore, the property of the air-fuel mixture in the warm-up process at the time of cold start of the internal combustion engine 2 can be improved and uniformized, and the distribution performance of the air-fuel mixture can be improved to stabilize the combustion. Therefore, it is possible to eliminate variations in the engine speed during the warm-up operation of the internal combustion engine 2, and it is possible to prevent fogging and smoldering of the spark plug.

[0034]

As described above, according to the present invention, the downstream side portion of the bypass passage is connected between the connecting surfaces at the time of joining the body side joint surface of the throttle body having the throttle valve incorporated therein and the intake manifold manifold side joint surface. At least one of the body-side joint surface and the manifold-side joint surface is provided with a bypass groove in which the width of the bypass passage is larger than the height of the bypass passage, so that the fuel and the bypass air are evenly mixed. And the properties of the air-fuel mixture can be made uniform, and the distribution performance of the air-fuel mixture can be maintained well,
It is practically advantageous. In addition, by maintaining good distribution performance of the air-fuel mixture, it is possible to stabilize the combustion of the internal combustion engine, reduce the variation in engine speed during warm-up of the internal combustion engine, and cause fogging and smoldering of the spark plug. Can be prevented, which is practically advantageous.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of an intake manifold having a bypass groove portion according to an embodiment of the present invention.

FIG. 2 is a cross-sectional explanatory view of a throttle body and an intake manifold.

FIG. 3 is a schematic plan view of an intake manifold in which a bypass groove portion is formed.

FIG. 4 is a diagram showing a relationship between an engine speed and an air-fuel ratio.

FIG. 5 is a cross-sectional explanatory view of a throttle body and an intake manifold showing a conventional technique of the present invention.

FIG. 6 is a schematic perspective view of an intake manifold having a bypass groove portion formed therein.

FIG. 7 is a schematic explanatory diagram of an internal combustion engine.

FIG. 8 is a diagram showing a relationship between an engine speed and an air-fuel ratio.

[Explanation of symbols]

 132 throttle body 132a body side joint surface 134 intake manifold 134a manifold side joint surface 146 body intake passage 148 manifold intake passage 150 throttle valve 174 idle adjustment bypass passage 176 first idle bypass passage 180 idle adjustment screw 182 first idle adjustment valve 202 bypass Passage 204 Bypass groove

[Procedure amendment]

[Submission date] July 16, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

Claims (1)

[Claims] 1. A bypass passage for bypassing a throttle valve provided in the intake passage to introduce bypass air into an intake passage downstream of the throttle valve, and a bypass air amount adjusting means provided in the bypass passage. In the internal combustion engine, when joining the body side joint surface of the throttle body in which the throttle valve is installed and the intake manifold manifold side joint surface, the body side joint is formed so as to expose the downstream side portion of the bypass passage between the connecting surfaces. An intake manifold for an internal combustion engine, characterized in that a bypass groove in which the width of the bypass passage is larger than the height of the bypass passage is provided on at least one of the surface and the manifold-side joint surface.