JPS61116068A - Inlet device for fuel injection type engine - Google Patents

Abstract

PURPOSE:To improve the diffusion for supplying the fuel and the atomization of the fuel by providing one fuel injection valve per one cylinder, fuel supply passages between the injection port and two inlet passages and a plate for diffusing the fuel within the inlet passage. CONSTITUTION:A first inlet passage 7 always supplies inlet air to a fuel combustion chamber 3, while a second inlet passage 8 is provided with an opening/ closing valve 11 to close when inlet air is less. In this case in the midst of inlet passages 7, 8 a fuel injection valve 20 is positioned. Between the inlet passages 7, 8 are formed two fuel supply passages 21, 22 divided into two from a base end member communication with an injection port 20a. Within the inlet passages 7, 8 fuel diffusion plates 27, 28 are at the place opposing to openings 21a, 22a of the lower stream end of each fuel supply passages 21, 22. Thereby, preventing the inlet passages 7, 8 from adhering fuel thereto at least when inlet amount and fuel supply amount are less.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an improvement in an intake system for a fuel injection engine that is equipped with two independent intake passages per cylinder and a fuel injection valve. It is something.

(Prior Art) Various types of intake systems have been developed in the past, each having two independent intake passages per cylinder. The second intake passage is opened and closed by an on-off valve or the like depending on the operating state. According to such a device, the second intake passage is closed and air is supplied only from the first intake passage, for example, at low speeds and low loads when there is little intake air flow, thereby increasing the intake flow velocity and improving combustibility. On the other hand, opening the second intake passage during high-speed field loads can reduce intake resistance and ensure output. Furthermore, by opening and closing the second intake passage, the area of the passage substantially changes and the period of intake pressure vibration changes, so this is utilized to enhance the inertial effect of intake over a wide operating range. It's also possible.

A fuel injection QJ valve is installed in such an intake system (one example is one in which fuel injection valves are installed in both intake passages, as seen in Japanese Utility Model Publication No. 57-167254, etc.), As seen in Japanese Patent No. 54-84128, there is a fuel injection valve installed only in the first intake passage. However, the former requires two fuel injection valves per cylinder, which increases the cost. According to the latter, when both intake passages are spaced apart, mixing of air and fuel within the combustion chamber tends to be insufficient compared to a case where fuel is distributed and supplied to both intake passages. In addition,
In addition to such a device, there is also a device in which two intake passages are partially merged in the middle and a fuel injection valve is placed at this merged part. Compared to the case where the two are independent, the effect of increasing the intake air flow velocity and the inertia effect of the intake air at low speeds and low loads mentioned above are reduced.

For this reason, there is a demand for supplying fuel from one fuel injection valve to two independent intake passages without merging in the middle. In order to satisfy such requirements, it is conceivable to send fuel from the fuel injection valve to both intake passages through a narrow passage, but in this case, the fuel sent to the intake passage is If a large amount of fuel adheres to the inner wall, combustion will become unstable, especially when the amount of intake air and fuel supply is small, so measures are required to prevent this situation.

(Object of the Invention) In view of the above circumstances, the present invention is capable of supplying fuel from one fuel injection valve to both the first and second intake passages which are independent of each other, and in particular, At least in the operating range where the intake air amount and fuel supply amount are relatively small, it is possible to prevent the fuel sent into the intake passage from adhering to the inner wall of the intake passage, and to improve the diffusion and atomization of the fuel within the intake passage. The purpose of the present invention is to provide an intake system for a fuel-injected engine that can be used in a fuel-injected engine.

(Structure of the Invention) The present invention provides a first intake passage that supplies air to each cylinder of an engine in the entire operating range of the engine, and a first intake passage that is closed by a passage closing means at least in an operating range where the amount of intake air is small. The second one, which supplies air only in the operating range.
In the intake passage provided independently from each other, one fuel injection valve is provided for each cylinder, and between the injection port of the fuel injection valve and the above-mentioned both intake passages, a fuel injection valve extending from the injection port is provided. Narrow fuel feeding passages each having an open end are disposed in both intake passages, and a plate for fuel diffusion is provided in at least the first intake passage facing the opening of the fuel feeding passage to the passage. It was established. In other words,
Fuel is fed from one fuel injection valve to both intake passages through a fuel feeding passage that is narrow enough not to impede the independence of the intake passages, and at least the first
The fuel sent into the intake passage is made to hit the plate and diffuse, thereby preventing the fuel from adhering to the inner wall of the intake passage.

(Embodiment) FIGS. 1 to 3 show an embodiment of the present invention. In these figures, 1 is an engine body, 2 is a plurality of cylinders arranged in this engine body, and 3 is each cylinder 2. 4 is an intake system for the engine body 2. In the intake system 4, two mutually independent intake passages 7.8 are provided per cylinder between the surge tank 6 connected to the intake introduction passage 5 and each cylinder 2.1. The downstream ends of both intake passages 7.8 shown in F open individually into the combustion chamber 3, and each opening 7a, 8a opens into the combustion chamber 3.
are opened and closed by intake valves 9 and 1o, respectively. Of the two intake passages 7.8, the first intake passage 7 always supplies intake air to the combustion chamber 3, and the second intake passage 8 supplies intake air only in a specific operating range.
There is an on-off valve (
Passage opening means) 11 is provided so that the passage 8 is closed by υ1 at least when the amount of intake air is small. In addition, an air cleaner 1 is provided in the intake air introduction passage 5.
2, an air flow meter 13 and a throttle valve 14 are provided. In addition, 15 is an exhaust passage, and 16 is a combustion chamber 3.
an exhaust valve equipped at the opening 16a of the exhaust passage 15 to
17 is a spark plug.

Reference numeral 20 denotes a fuel injection valve, which injects fuel from an injection port 20a that is opened and closed by a valve body operated by a solenoid as is well known. It is controlled by a control circuit (not shown) so as to inject fuel at a predetermined timing according to the timing. This fuel injection valve 20 is arranged approximately in the middle of both the intake passages 7.8.

The injection port 20a of the fuel injection valve 20 and both intake passages 7
.
2 is formed. Both fuel supply passages 2L and 22 are formed in a straight line and extend obliquely toward the downstream side of the intake passage, with downstream ends opening into the respective intake passages 7.8.

In addition, each fuel feeding passage 21.22 is compared with each intake passage 7, 8 so that air can be sufficiently suppressed from flowing between both intake passages 7, 8 through the fuel feeding passage 21.22. Specifically, the cross-sectional area of each intake passage 7,
8.115 or less, and the downstream sides of the fuel feed passages 21 and 22 are formed to be somewhat thicker than the upstream sides so as to accommodate the spread of the fuel injected from the fuel injection valve 20. As for the positional relationship between the on-off valve 11 in the second intake passage 8 and the downstream end opening 22a of the second fuel feeding passage 22, the on-off valve 11 may be disposed upstream of the opening 22a as shown in the figure. Alternatively, it may be placed downstream from the opening.

Assist air may be supplied to each of the fuel supply passages 21, 22 in order to promote atomization of the fuel and to effectively control the direction of fuel supply. In the embodiment shown in the figure, two assist air passages 24 and 25 per cylinder are branched from a passage 23 whose upstream end is connected to the intake introduction passage 5 between the air meter 13 and the throttle valve 14. The assist air passages 24 and 25 are respectively opened in the passage walls on both sides in the vicinity of the injection port 20a. One of the assist air passages 24, which opens from the wall surface on the side of the first fuel supply passage 21 toward the second fuel supply passage 22, is provided with a solenoid valve that is operated to open in correspondence with the on-off valve 11. A control valve 26 is provided, and when the on-off valve 11 is closed, the control valve 26 controls one of the assist air passages 24.
is closed and assist air is supplied only from the other assist air passage 25 toward the first fuel feeding passage 21, so that the fuel injected from the fuel injection valve 20 is supplied to the first fuel supply passage 21.
The air is deflected toward the intake passage 7 side. In order to effectively exert the effect of adjusting the fuel supply direction by the assist air, fuel injection from the fuel injection valve 20 is performed during the intake stroke at least in the operating range where the second intake passage 8 is closed. It is desirable to keep it.

Further, inside the intake passage 7.8, a mixing plate (a plate for fuel diffusion) is provided at a position facing the downstream end openings 21a, 22a of each fuel supply passage 21.22.
27.28 are arranged.

In the illustrated example, the mixing plates 27 and 28 are formed of perforated plates, and are attached to the tips of protrusions 21b and 22b that protrude into the intake passages 7 and 8 from around the openings 21a and 22a.

FIG. 4 shows an example of an area in which the on-off valve 11 is opened and an area in which it is closed. At lower speeds than this, fiil V
The JI valve 11 is closed, and the on-off valve 11 is heard on the high rotation side. By doing this, when the amount of intake air is small and the engine load is low and the rotation speed is low, the intake air is introduced into the combustion chamber 3 only through the first intake passage 7, so that the intake flow velocity is increased and an intake swirl is created in the combustion chamber 3. On the other hand, even during high-load, high-speed rotation with a large amount of intake air, the intake air is introduced into the combustion chamber 3 through both intake passages 7.8, so that intake resistance does not increase. , a decrease in the intake air filling amount is prevented. In addition, due to the propagation of pressure waves between each cylinder 2 and the surge tank 6, intake pressure oscillations occur in the intake passage of each cylinder, and the frequency of this intake pressure 1til+ increases as the cross-sectional area of the intake passage becomes larger. Therefore, by operating the on-off valve 11 as described above, the cross-sectional area of the intake passage is substantially reduced in the low-speed range, and the cross-sectional area of the intake passage is increased in the high-speed range, thereby reducing intake pressure vibration in the low-speed range and the high-speed range, respectively. By matching the opening and closing cycles of the intake valves, the inertia effect of the intake air is enhanced, increasing intake air filling efficiency under high loads at both low speeds and high speeds, thereby increasing output. Therefore, the on-off valve 11
The opening/closing control may be controlled in a low speed range using only a signal of the rotational speed, and the specific operation may be controlled via an actuator by a control circuit not shown. .

In the intake system configured as described above, when the on-off valve 11 is open at high load and high speed, etc., intake air is supplied to the combustion chamber 3 through both intake passages 7 and 8; Since fuel is distributed and supplied to the passage 7.8 from one fuel injection valve 20 per cylinder through each of the fuel feed passages 21.22, approximately An air-fuel mixture in which air and fuel are evenly mixed is supplied, and the concentration of the air-fuel mixture within the combustion chamber 3 is reliably prevented from becoming uneven. Further, during low load and low rotation times when the on-off valve 11 is closed, intake air is supplied to the combustion chamber 3 through the first intake passage 7. In this case, both intake passages 7,
The fuel supply passages 21.22 communicating with the intake passages 7.8 are formed to be narrow, and the flow of intake air between the intake passages 7.8 is sufficiently suppressed, so that the intake passages 7.8 are substantially independent from each other. This state is maintained, and the effects of increasing the intake flow rate and creating an intake swirl, and the effects of increasing the intake inertia effect are maintained well. Furthermore, in this case, if the fuel delivery direction is adjusted as described above by the assist air passages 24 and 25 and the control valve 26 provided in one of the passages 24, the fuel injected from the fuel injection valve 20 can be adjusted. Most of the fuel is sent into the first intake passage 7, and the first
It mixes with the air flowing through the intake passage 7 and is supplied to the combustion chamber 3.

In this way, the fuel injected from the fuel injection valve 20 is distributed and supplied to both intake passages 7.8 through the fuel feed passages 21, 22, or is deflected and supplied to the first intake passage 7, but in this case, If the downstream ends of the fuel feed passages 21, 22 are simply opened to the intake passages 7 and 8, the fuel sent out from the fuel feed passages 2L and 22 tends to adhere to the inner wall of the intake passages. Therefore, the mixing plate 27.2
8 is provided to prevent such a situation. In other words, the fuel sent out from the fuel feed passages 21 and 22 hits the mixing plates 27 and 28 and is dispersed into the intake air, so that a large amount of fuel is prevented from adhering to the inner wall of the intake passage, and the mixing effect of the air is prevented. is enhanced. In particular, if the mixing plates 27 and 28 are made of perforated plates, it is advantageous for mixing with air.

In the above embodiment, mixing plates 27 and 28 are provided in both intake passages 7 and 8, but problems such as unstable combustion occur when a large amount of fuel adheres to the inner wall of the intake passage. When the intake air amount a5 and the fuel supply amount are small, that is, when intake is performed only through the first intake passage 7, the mixing plate may be provided only in the first intake passage 7.

In addition to this, the specific structure of each part in the device of the present invention can be modified in various ways. For example, even in the closed state, the on-off valve 11 may allow a small amount of air to flow through the second intake passage 8 without completely blocking it. Even if some amount of fuel enters the combustion chamber 3, this fuel can be well atomized and sent to the combustion chamber 3. Second
As a means for opening and closing the intake passage 8 according to the operating state,
Instead of the above-mentioned on-off valve 11, an intake valve 10 on the downstream side of the second intake passage 8 is inactivated at low load and low rotation, or at low load and low rotation, and at high load and low rotation, similar to the closing operation range of the on-off valve 11. A mechanism may also be adopted.

Furthermore, in the embodiment shown in the figure, the downstream ends of both intake passages 7 and 8 are individually opened into the combustion chamber 3, and intake valves 9 and 10 are provided at each opening, but the intake valves are located close to each other. As long as both intake passages are formed independently to the position where
Two intake valves may be shared by both intake passages.

Further, the fuel injection valve 20 may be one used in a general fuel injection type engine, but by making the injection port 20a into an elliptical shape or the like, the fuel can be transferred to both the fuel supply passages 21 and 22. It is also possible to have a structure in which the liquid is dispersed and injected.

(Effects of the Invention) As described above, the present invention provides a thin fuel supply from a fuel injection valve to two mutually independent intake passages, the first intake passage and the second intake passage that is closed when the intake air amount is small. Since fuel is distributed and supplied through the supply passages, fuel can be distributed and supplied to both intake passages from one fuel injection valve per cylinder while maintaining the independence of both intake passages. In addition, in particular, at least the first intake passage is provided with a fuel diffusion plate facing the opening of the fuel supply passage, so that at least when the intake air amount and fuel supply amount are small, the fuel will be distributed to the inner wall of the intake passage. Prevents much adhesion to
It is possible to stabilize combustion by increasing the mixing effect with air.

[Brief explanation of drawings]

Fig. 1 is a schematic plan view of the overall structure of an embodiment of the device of the present invention, Fig. 2 is an explanatory view of its main parts, Fig. 3 is a sectional view showing the specific structure, and Fig. 4 is a second intake passage. FIG. 2 is an explanatory diagram showing regions in which the on-off valves numbered are opened and regions in which they are closed. DESCRIPTION OF SYMBOLS 1... Engine body, 2... Cylinder, 7, 8... Intake passage, 20... Fuel injection valve, 21.22... Fuel feeding passage, 27.28... Mixing plate. Patent applicant: Mazda Motor Corporation Kan II2I

Claims (1)

[Claims] 1. A first intake passage that supplies air to each cylinder of the engine in the entire operating range of the engine, and a first intake passage that is closed by a passage closing means at least in an operating range where the intake air amount is small and supplies air only in a specific operating range. In the intake passage in which the second intake passage and the second intake passage are provided independently from each other, one fuel injection valve is provided for each cylinder, and between the injection port of this fuel injection valve and both intake passages, A thin fuel feeding passage extending from the injection port and having an open end in each of the intake passages is disposed, and a narrow fuel feeding passage is provided in at least the first intake passage facing the opening of the fuel feeding passage to this passage. An intake device for a fuel-injected engine characterized by being provided with a plate for fuel diffusion.