JPS61118559A - Intake unit of fuel injection type engine - Google Patents

Abstract

PURPOSE:To improve stability of combustion by supplying fuel from a single fuel injection valve to two independent intake paths to operate a fuel supply direction regulator for deflecting fuel to a first intake path when a second intake path is closed. CONSTITUTION:Fuel is supplied from a single fuel injection valve 20 to first and second intake paths 7, 8 through first and second fuel supply paths 21, 22. On the way of these fuel supply paths are opened assist air paths 25, 24. The first assist air path 24 is opened from the side wall of the second fuel supply path 22 side toward the first fuel supply path 21. And in low load and speed rotation or the like in which a switch valve 11 in the second intake path 8 is closed, a controlling valve 26 is closed and air is supplied to the first fuel supply path 21 only from the first path 24 to deflect fuel to the first intake path 7 side.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is directed to an improvement in the intake system of a fuel-injected engine that is provided with mutually independent intake passages for each cylinder and equipped with a fuel injection valve. It is something.

(Prior Art) Various intake systems having two mutually independent intake passages per cylinder have been developed. The intake passage is opened and closed depending on the operating condition using a 58m valve or the like. According to such a device, for example, at low speeds and low loads when the amount of intake air is small, the second intake passage is closed and air is supplied only from the first intake passage, thereby increasing the intake flow velocity and improving combustibility. On the other hand, at high speeds and high loads, by listening to the second intake passage, intake resistance can be reduced and output can be ensured. 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 can be used to enhance the inertial effect of intake air over a wide operating range. You can also do it.

Examples of such an intake system equipped with a fuel injection valve include one in which fuel injection valves are provided in each of both intake passages, as seen in Japanese Utility Model Application Laid-Open No. 57-167254, or Japanese Unexamined Utility Model Publication No. 54-84128. As seen in Japanese Patent Publication No. 1, there is a type in which a fuel injection valve is provided only in the first intake passage. However, according to the former, two fuel injection valves are required for each cylinder, which is disadvantageous in terms of cost, and according to the latter, when both intake passages are open, fuel is distributed and supplied to both intake passages. Mixing of air and fuel within the combustion chamber is likely to be insufficient compared to other combustion chambers. In addition to this type of 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 portion. Compared to a configuration with two independent intake passages, the effect of increasing the intake flow velocity and the inertia effect of intake air at low speeds and low loads as described 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. Furthermore, in order to satisfy this requirement, if the structure is such that only one fuel injector distributes and supplies fuel to both intake devices, even when the second intake passage is closed, Fuel is pumped into
Since fuel atomization and mixing with air become insufficient and combustion within the fuel chamber becomes unstable, measures are required to prevent such a situation.

(Objective of the Invention) In view of the above circumstances, the present invention is capable of distributing fuel from one fuel injection valve to both the first and second intake passages, which are independent of each other, and is capable of distributing fuel to the first and second intake passages, which are independent of each other. The present invention provides an intake device for a fuel injection engine that can deflect and feed fuel toward the first intake passage in an operating range in which intake air is supplied to the chamber only from the first intake passage.

(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 intake m is small. In an intake passage that supplies air only in the operating range and a second intake passage that is independent of each other, 11 per cylinder! J fuel injection valve is provided, and between the injection port of the fuel injection valve and the above-mentioned both intake passages, a pair of narrow fuel feeds are provided, each branching from the above-mentioned injection port and having a tip opening in each of the intake passages. Along with arranging passageways,
Connecting air passages that open from two directions toward the fuel feeding passage on the first intake passage side and the fuel feeding passage on the second intake passage side, respectively, near the base end confluence of the two fuel feeding passages, In addition, in an operating range where the second intake passage is closed, the air passage is provided with a 1II11 control valve that introduces air only from the air passage that opens toward the first intake passage. In other words, 111! ] The fuel is sent from the fuel injection valve to both intake passages through a narrow fuel feeding passage that does not impede the independence of both intake passages, especially when intake is being carried out from both intake passages. In this case, air is introduced into the fuel feeding passages for both intake passages to distribute fuel separately, and when air is being taken only from the first intake passage, air is introduced into the fuel feeding passage on the first intake passage side. The fuel is deflected toward the first intake passage by introducing air toward the first 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 1, and 3 is each cylinder. 2 combustion chambers, 4
is an intake system for the engine body 1. Above intake system 4
, two mutually independent intake passages per cylinder, that is, first and second intake passages 7 and 8, are provided between the surge tank 6 connected to the intake introduction passage 5 and the passenger air n2,
The downstream ends of both the intake passages 7, 8 are individually opened into the combustion chamber 3, and the respective openings 7a, 8a are connected to the intake valves 9, 1, respectively.
It is opened and closed by 0.

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. is provided with an on-off valve (passage closing means) 11 that opens and closes the passage 8 depending on the operating state, and the passage 8 is closed at least when the amount of intake air is small. In addition, the air intake introduction passage 5 includes an air cleaner 12 and an air 70.
- A meter 13 and a throttle valve 14 are provided. In addition, 15 is an exhaust passage, 16 is an exhaust valve equipped at the opening 16a of the exhaust passage 15 to the combustion chamber 3, and 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, and is detected by the air meter 13. It is controlled by an hl'llJ circuit (not shown) to inject fuel at a predetermined timing according to the amount of intake air. 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 the intake vents! g
IM with 7.8 includes first and second fuel supply passages 21 that are bifurcated from the base end leading to the injection port 20a.
．． 22 is formed. Both fuel supply channels rE21.
22 is formed in a straight line and extends obliquely toward the downstream side of the intake passage, with its downstream end opening into each intake passage 7.8.

In addition, each fuel feeding passage 21.22 is larger than each intake passage 7.8 in order to sufficiently suppress the flow of air in both intake passages 7, 811 through the fuel feeding passage 21.22. Each intake passage 7 is made considerably thinner, specifically in terms of cross-sectional area.
．． 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. The r#m valve 11 in the second intake passage 8
As for the positional relationship between
L] may be placed upstream from the opening, or may be placed downstream from the opening.

A pair of first and second assist air passages are provided to both the fuel supply passages 21 and 22 for introducing assist air to promote fuel atomization and effectively control the fuel supply direction. (Air passage) 24°25 is provided.

Each of the assist air passages 24.25 branches from the passage 23 whose upstream end is connected to the intake air introduction passage 5 between the air 70-meter 13 and the throttle valve 14, and branches off from the passage 23, which has an upstream end connected to the intake air introduction passage 5 between the air 70-meter 13 and the throttle valve 14. The first assist air passage 24 opens toward the first fuel supply passage 21 from the side wall on the second fuel supply passage 22 side, and the 297th assist air passage 25 opens from the side wall on the second fuel supply passage 22 side. It opens toward the second fuel feeding passage 22 from the side wall of the fuel feeding passage 21 rAq. The second assist air passage 25 is provided with a υ control valve 26 using a city magnetic valve or the like that opens and closes in correspondence with the on-off valve 11.
is provided, that is, the control valve 26 controls the on-off valve 1.
In the operating range where the 27th assist air passage 1 is closed, the second assist air passage 25 is closed to
The assist 17 passage 24 is always open. In order to effectively exert the effect of adjusting the fuel feeding direction by the assist air passages 24, 25 and the III control valve 26, the air flow from the fuel injection valve 20 is reduced at least in the operating range where the second intake passage 8 is closed. It is desirable that fuel injection be performed during the intake stroke.

Further, 27 and 28 are mixing plates made of a perforated plate for enhancing the mixing effect of fuel and air in each intake passage 7 and 8, and are provided in each intake passage 7 and 8: Multi-fuel feeding passage 21. It is placed opposite the tip opening of 22.

FIG. 4 shows an example of an area in which the on-off valve 11 is opened and an area in which the on-off valve 11 is opened. On the lower rotation side, the on-off valve 11
is closed, and the on-off valve 11 is heard on the high rotation side. By doing this, when the intake air m 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. This results in better flammability, and on the other hand,
Both intake passages 7 and 8 should be
Since the intake air is introduced into the combustion chamber 3 through the combustion chamber 3, the intake resistance does not increase and the intake air filling amount is prevented from decreasing.

In addition, due to the propagation of pressure waves between the 6th air tii2 and the surge tank 6d, intake pressure imaging occurs in the intake passage of each cylinder, and the frequency of this intake pressure oscillation 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 increasing the intake pressure in the low-speed range and the high-speed range, respectively. By matching the shooting to the intake valve FiI quiet period, the inertial effect of the intake air is enhanced, increasing the intake air filling efficiency under high loads at both low speeds and high speeds, and improving output. Therefore, the opening/closing control of the opening/closing valve 11 may be made such that it opens in a low speed range using only a signal of the rotation speed, and the specific operation is controlled by a control circuit (not shown) via an actuator. Just do it like this.

In addition, the control valve 26 may also be controlled in accordance with this. In the above specific example, the opening/closing valve 11 is switched to open/close at the engine speed reference value, but within a certain operating range, the opening/closing valve 11 may be operated in response to changes in operating conditions. The opening degree of the open/close valve 11 may be controlled to gradually change from an open state to a fully open state. In this case, the control valve 26
The opening degree may also be changed according to the operating state so as to correspond to the opening degree of the on-off valve 11.

In the intake system configured in this way, intake air is supplied to the combustion chamber 3 through both the intake passages 7 and 8 during high load and high rotation when the on-off valve 11 is open. In this case, assist air is introduced into both the fuel supply and oil passages 21 and 22 from the assist air passages 24 and 25, respectively, and the assist air atomizes the fuel injected from the fuel injection valve 20 while Fuel supply passage 21.22
The air is distributed to both intake passages 7 and 8 through the air. Therefore,
An air-fuel mixture in which air and fuel are mixed almost evenly is supplied to the combustion chamber 3 from both intake passages 7 and 8, and the concentration of the air-fuel mixture within the combustion chamber 3 is reliably prevented from becoming uneven. Ru. Further, during low load and low rotation when the on-off valve 11 is closed, intake air is supplied to the combustion chamber β through the f#1 intake passage 7, but in this case, the intake air is supplied to the combustion chamber β through the f#1 intake passage 7. The fuel supply passages 21 and 22 are formed narrowly, and both intake passages 7
Since the flow of intake air between 8° and 8° is sufficiently suppressed, both intake passages 7 and 8 remain substantially independent, increasing the intake flow velocity, creating an intake swirl, and reducing intake inertia. The effect-enhancing effect will be maintained well. In this case, the assist air passage 25 is closed by the control valve 26, so that assist air is introduced from only the first assist air passage 24 toward the first fuel supply passage, and the airflow of this assist air causes , the fuel is deflected toward the first fuel feed passage 21 , and most of the fuel is sent into the first intake passage 7 . Therefore, when air is being taken only from the first intake passage 7, a correspondingly appropriate fuel supply is performed, and even in this case, the atomization of the fuel becomes poor, and the fuel inside the fuel chamber 3 is not unevenly distributed, and good combustibility is maintained.

Note that the specific structure of each part in the device of the present invention can be modified in various ways. For example, the on-off valve 11 may allow a small amount of air to flow through the second intake passage 8 without completely opening the second intake passage 8 even in the closed state. Even if some amount of fuel enters the combustion chamber 3, this fuel can be well atomized and sent to the combustion chamber 3. As a means for opening and closing the second intake passage 8 according to the operating state, an intake valve 1 on the downstream side of the second intake passage 8 is used instead of the on-off valve 11 described above.
It is also possible to adopt a mechanism in which the on-off valve 11 is inoperative during low load and low rotation, or during low load and low rotation and high load and low rotation, similar to the idle operating range of the on-off valve 11.

In addition, in the embodiment shown in the figure, the downstream ends of both intake passages 7.8 are individually opened into the combustion chamber 3, and intake valves 9 and 10 are respectively arranged in each opening. As long as both intake passages are formed independently until they are close to each other, 1
Two intake valves may be shared by both intake passages.

Further, the fuel Fl injection valve 20 may be one used in a general fuel injection type engine, but
The injection port 20a may have an elliptical shape or the like so that the fuel is injected in a distributed manner into both the fuel supply passages 21 and 22.

(Effects of the Invention) As described above, the present invention provides a pair of thin intake passages from the fuel injection valve to two mutually independent intake passages, the first intake passage and the second intake passage that is closed when the amount of intake air is small. Since the fuel is distributed and supplied through the fuel supply passage,
1il per cylinder while maintaining the independence of both intake passages
Fuel can be distributed and supplied to both intake passages from the fuel injection valve.

Moreover, especially in the operating range where air is taken from both intake passages, air is introduced from two directions into each fuel supply passage for both intake passages, thereby dividing and feeding fuel to both intake passages. In the operating range where air intake is only from the passage,
By introducing air toward the fuel feed passage on the first intake passage side, the fuel is deflected in this direction, so in any operating range, fuel atomization may be poor or the fuel may not be in the fuel chamber. There is no uneven distribution of fuel, and the fuel
It improves flammability and prevents deterioration of output, fuel efficiency, emissions, etc.

[Brief explanation of the drawing]

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. The area where the on-off valve provided in l! is opened and l! FIG. DESCRIPTION OF SYMBOLS 1... Engine body, 2... Cylinder, 7... First intake passage, 8... Second intake passage, 20... Fuel injection valve, 21° 22... Fuel feeding passage, 24.25...Assist air passage (air passage), 26...Control valve. Figure 1

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 pair of narrow fuel supply passages are provided that branch from the injection port and have their respective tips open in both intake passages, and a first The air passages opening toward the fuel feeding passage on the intake passage side and the fuel feeding passage on the second intake passage side are connected, and in an operating range where the second intake passage is closed, the air passage opens toward the fuel feeding passage on the first intake passage side. An intake device for a fuel injection engine, characterized in that the air passage is provided with a control valve that introduces air only from the air passage that opens toward the air.