JPS58107813A - Intake device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To step up the atomization of the fuel in an intake passage for a low load by providing the second throttle valve in an intake passage for a high load in a duplex intake device with intake passages for a low load and high load. CONSTITUTION:An intake manifold 5 and the intake port 14 in a cylinder head 9 are divided into two by a bulkhead 6 and separation wall 10 to form low load intake passages 7, 11 with a small diameter and high load intake passages 8, 12 with a large diameter, and low load and high load carburetors 3, 4 which are a part of a carburetor 2 respectively are provided upstream the individual passages 7, 8. Therein, the second throttle valve 19 is provided in the passage 8 separately from throttle valves 17, 18 of the carburetor 2. A nozzle hole 20 is bored on a bulkhead 6 near the intake upstream side of the second throttle valve 19, and a nozzle 21 is provided on it toward the passage 7. Accordingly, a part of the intake air introduced into the passage 8 through a communication hole 23 under a low or medium load is again sprayed into the passage 7 through the nozzle 21 to step up the atomization of the fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine intake port that is divided into two passages: a low-load intake passage and a high-load intake passage.

2. Description of the Related Art Conventionally, an engine intake system, a so-called multiple intake system, is generally well known, in which two intake passages, one for low load and one for high load, are independently opened in the combustion chamber of the engine.

This dual intake system uses only the small-diameter low-load intake passage to increase the air-fuel mixture flow rate and promote fuel atomization during low- to medium-load conditions, including idling. The air-fuel mixture is also supplied from the intake passage to improve output.

Compared to the conventional intake system with a single intake passage, engines equipped with the above-mentioned dual intake system promote fuel vaporization and atomization at low loads, or use a directional port, which allows intake air to flow tangentially to the cylinder. Let it flow,
It has various advantages such as improving combustion efficiency by strengthening the swirl in the combustion chamber by combining intake ports and the like that generate swirl in the cylinder.

Therefore, the present invention provides an engine equipped with the above-mentioned dual intake system, in which a second throttle valve is provided in the high-load intake passage, and on the intake upstream side 1 of the second throttle valve, the low-load intake air is drawn from the middle of the high-load intake passage. Let the intake air blow out in the middle of the passage,
This is designed to further promote aeration and atomization of the fuel in the low-load intake passage, thereby promoting the original function of the dual intake system.

The present invention will be explained below based on the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.

First, to explain the configuration, the intake port 14 formed in the cylinder head 9 is connected to the intake manifold 5 on the upstream side, and the cylinder body 1 on the downstream side via the intake valve 13.
Combustion chamber 1 formed by 5 and cylinder head 9
It opens at 6. Further, the upstream side of the intake manifold 5 is connected to a carburetor 2, and the carburetor 2 is connected to an air cleaner l. Intake port i in the intake manifold 5 and cylinder head 9 A partition wall 6 formed in the intake manifold 5 and a partition wall connected to the downstream end of the partition wall 6 and integrally formed with the cylinder head 9 The IO divides into two to define a small-diameter low-load intake passage 7.11 and a large-diameter high-load intake passage 8, 12, each of which independently communicates from the intake port H4 to the combustion chamber I6.

The low-load intake passages 7, 11 are provided with a low-load carburetor 3, which is a part of the carburetor 2, upstream, and the high-load intake passages 8, 12 are provided with a part of the carburetor 2 upstream. A high-load carburetor 4, which is a part, is provided to constitute a dual intake system. In addition, the throttle valve 17 of the carburetor 2 is located in the high-load intake passage 8.
, 18, a second throttle valve 19 is provided, and its opening/closing is controlled by linkage with the carburetor throttle valve 17, which is a known technique, or by negative pressure in the intake road for low loads. This is due to factors such as the operation of the dial.

Furthermore, a nozzle 2 is provided in the partition wall 6 that defines the low-load intake passage 7 and the high-load intake passage 8 near the intake upstream side of the second throttle valve 19.
0 is bored, and a nozzle 21 is attached to the jet port 20 toward the low-load intake passage 7. Further, an engine cooling water passage 24 is provided below the low-load intake passage 7.

Further, the high-load intake passage 8 and the low-load intake passage 7 are provided with a communication hole 23 directly below the throttle valves 17 and 18 of the carburetor 2, and the communication hole 28 is connected to the low-load intake passage of the carburetor 2. It is formed on the side opposite to the low-speed fuel supply section 3a of the fuel tank 8, and is configured to mainly guide a part of the intake air to the high-load intake passage 8.

Next, the effect will be explained. In the engine equipped with the above-mentioned dual intake system, the passage area of the low-load intake passages 7 and 11 is narrowed down to increase the flow velocity of intake air, so the low-load intake passages 7 and 11 are made compact so that only the low-load carburetor 8 is used. At medium load, the air-fuel mixture flows through the low-load intake passage 7.11 at a high flow rate, promoting vaporization and atomization of the fuel, and a strong swirl is generated within the combustion chamber 16, thereby reducing combustion efficiency. At the same time, a portion of the intake air that has passed through the low-load carburetor 3 is diverted through the communication hole 23 provided directly below the throttle valve 17 of the low-load carburetor 3, so that only the air is raised to a high temperature. It is designed to be introduced into the load intake passage 8.

Further, a part of the intake air, preferably air, introduced into the high-load intake passage 8 is passed through a nozzle 20. The air is ejected from the nozzle 21 into the low-load intake passage 7 again.

The jet port 20 and the nozzle 2 are still in the low-load intake passage 7.
Since the engine cooling water passage 24 is provided below the nozzle 21, the pipe wall 22 is warmed.
Part of the intake air, preferably air, blown out from the engine is sufficiently mixed with the intake air-fuel mixture in the low-load intake passage 7, and the vaporization of the fuel is further promoted. When the load is high, the high-load carburetor 4 operates and the second throttle valve 19 opens, thereby supplying intake air from the large-diameter high-load intake passage 8.12 to the combustion chamber 16 to improve output. I'm trying to figure it out.

Furthermore, the throttle valve 18 and second throttle valve 19 of the high-load carburetor are configured to be closed during low- to medium-load conditions when the low-load intake passage 7.11 is used, but in reality, the throttle valve 18 and the second throttle valve 19 are closed. valve 18,
19 and the pipe wall of the high-load intake passage 8, if the communication hole 23 and the nozzle 20 are not provided, the low-load intake passage 7. It is not possible to secure a sufficient intake air flow velocity in the cylinder 1, and the swirl control to the combustion chamber 16 is not performed in the intake boat 14 in the nozzle 9 to the cylinder.
The leaked intake air from No. 12 and the intake air from the low-load intake passages 7 and 11 interfere with each other and are weakened. Therefore, if the nozzle 20 is provided as in the present invention and the communication hole 28 is set to have a smaller passage area than the nozzle 20, the second throttle valve t
It is possible to reduce leakage of intake air from the air outlet 20, further increase the flow velocity in the low-load intake passages 7 and 11 after the injection port 20, and further promote swirl in the combustion chamber 16.

1. By providing the nozzle 20 near the intake upstream side of the second throttle valve 19, fuel liquid that adheres to the pipe wall of the load intake passage 8 and flows when the second throttle valve 19 is opened from the open state can be prevented. This prevents the nuclear fuel liquid from stagnation near the second throttle valve 19, and enables the nuclear fuel liquid to be injected into the low-load intake passage 7 and sufficiently atomized and vaporized. In this embodiment, the case where the communication hole 23 is provided has been described, but the throttle valve 18 of the high-load carburetor 4
The communication hole 23 may be eliminated by controlling the intake air leakage amount to be constant.

Furthermore, from the engine operating range where only the low-load intake passage operates to the engine operating range where the high-load intake passage also operates, that is, the operating range where the throttle valve 18 of the high-load carburetor 4 begins to open, the high-load intake Because the intake flow velocity of passage 8 is low, intake passage 8 for high load
The fuel easily flows through the inner pipe wall while remaining in liquid form. Therefore, the second
If the opening timing of the throttle valve 19 is set slightly to the higher load side than the throttle valve 18 of the high-load carburetor 4, the mixture supplied from the high-load carburetor 4 to the low-load intake passage 7 from the nozzle 20 can be adjusted. Qi also flows into it. This allows the engine to smoothly transition from the low-medium load operating range to the high-load operating range.

Figure 2 shows an example of Noh.1. This embodiment is partially different from the embodiment shown in FIG. 1 in the structure of the multiple intake system. i.e. cylinder head 9” intake boat 14”
There is no separation wall that divides the intake passage into low-load intake passage and high-load intake passage, and the intake manifold is connected on the upstream side.・Only a partition wall 6' is formed in the section.The partition wall 6' defines a small-diameter low-load intake passage 7' and a large-diameter high-load intake passage 8', which are divided into two parts. In addition to the throttle valves 17 and 18 of the carburetor 2, a second throttle valve 19° is provided in the high-load intake passage 8°, and a second throttle valve 19° is provided in the high-load intake passage 7° and in the high-load intake passage 8°. The upstream ends of the two are connected to each other through a single intake passage 25 of the intake manifold 5'.

When the engine is at low or medium load, the intake air supplied by the low-load carburetor 8 flows down through the single intake passage 25 at 5° of the intake manifold, and the air-fuel mixture flows through the low-load intake passage at 7° at a high flow rate. At the same time, the intake air is deflected at the intake boat 14° of the cylinder head 9'', and a swirl is generated in the combustion chamber 16'.
This increases combustion efficiency. At this time, in the single intake passage 25 of the intake manifold 519-, the fuel engine liquid is non-uniformly adhered to and flows around the entire circumference of the pipe inside the pipe inner wall 26.

At the part where the liquid fuel film all around the pipe is separated into the low-load intake passage 7'' and the high-load intake passage 8'', the liquid film of fuel also jumps into the high-load intake passage 8' due to inertia. I'll go. Therefore, the fuel liquid accumulates near the second flow side of the second throttle valve 19' provided in the high-load intake passage 8', so the accumulated fuel liquid is transferred to the nozzle just before the second throttle valve 1σ. The air-fuel mixture is configured to be ejected and diffused into the low-load intake passage 7° through a 20t nozzle 21'2, and the air-fuel mixture ejected from the nozzle 21' is passed through the low-load intake passage 7° pipe. Since it collides with the wall 22', vaporization and atomization of the fuel is promoted.

The action of the force is similar to that of the embodiment shown in Fig. 1 (in this embodiment, the partition wall 6° is only provided in a part of the intake manifold 5'', and the intake passage 8' for high load and the intake passage 8' for low load Intake passage 7
1, the structure is simpler than the embodiment shown in FIG. 1, and it can be produced at low cost and has excellent mass productivity.

In addition, the nozzle/L'21.21 in both the embodiments shown in FIG. 1 and FIG.
Although the example in which the nozzle opening is 20.2σ has been described, almost the same effect can be obtained with only a nozzle opening of 20.2σ.

As explained above, according to the present invention, in an engine equipped with a dual intake system, a second throttle valve is provided in the high-load intake passage downstream of the carburetor/throttle valve, and the second throttle valve By providing a nozzle that communicates from the middle of the upstream high-load intake passage to the middle of the low-load intake passage, it is possible to further promote vaporization and atomization of the fuel in the low-load intake passage. Since the fuel liquid on the upstream side of the second throttle valve provided can also be mixed well with the intake air in the low-load intake passage, the combustion

[Brief explanation of the drawing]

FIG. 1 is an explanatory sectional view showing an embodiment of the present invention, and FIG. 2 is an explanatory sectional view showing an embodiment of a pond of the invention.

Claims (1)

[Scope of Claims] (1) A mixture intake hole that opens into the cylinder combustion chamber and is opened and closed by an intake valve is connected to two air-fuel mixture intake passages, a low-load intake passage and a high-load intake passage, over substantially the entire length or part of the intake hole. In an internal combustion engine that is separated into two passages, a second throttle valve is provided in the high-load intake passage downstream of the carburetor throttle valve, and
An intake system for an internal combustion engine, characterized in that a nozzle is provided that communicates from midway through a high-load intake passage downstream of a carburetor throttle valve and upstream of the second throttle valve to midway through a low-load intake passage. (2) When the second throttle valve provided in the high-load intake passage is in the closed state, the injection port from the high-load intake passage to the low-load intake passage is connected to the An intake system for an internal combustion engine according to claim 1, wherein the intake passage is provided in a partition wall separating the intake passage for a load and the intake passage for a high load. (8) The low-load intake passage and the high-load intake passage communicate with each other downstream of the carburetor throttle valve and upstream of the nozzle hole formed in the partition wall. An intake system for an internal combustion engine as described in (2).