JPH0636293Y2 - Fuel injector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a fuel injection device suitable for injecting and supplying fuel into an intake passage of, for example, an automobile engine, and more particularly, The present invention relates to a fuel injection device capable of reliably promoting atomization.

[Conventional technology]

Generally, there is known a fuel injection device in which an injection valve is provided in an intake passage of an automobile engine or the like, and fuel is injected and supplied from the injection valve into the intake passage.

Further, in this type of fuel injection device, there are one in which an injection valve is arranged upstream of a throttle valve provided in the middle of the intake passage, and one in which an injection valve is arranged downstream of the throttle valve. The fuel injected from the injection valve is mixed with the intake air flowing through the intake passage to form a mixture, which is supplied to the combustion chamber of the engine.

By the way, in this type of conventional technology, when the injection valve is arranged on the upstream side of the throttle valve, the intake air flowing around the throttle valve becomes a subsonic state and the flow velocity increases, so that the fuel from the injection valve is increased. Is atomized by the air flow around the throttle valve and can promote atomization, but after this fuel adheres to the throttle valve, it is gradually sent out to the downstream side by the air flow, so there is a transient during engine acceleration etc. It has drawbacks such as poor responsiveness and poor low temperature startability. Further, when the injection valve is arranged on the downstream side of the throttle valve, the transient response and the low temperature startability can be improved, but the flow velocity of the air flow after passing through the throttle valve is reduced. However, the fuel cannot be atomized and atomization cannot be promoted.

Therefore, the present applicant has previously filed a patent application 63
As No. 115391 (hereinafter referred to as prior art), a fuel injection device as shown in FIGS. 4 to 7 has been proposed.

In the drawing, reference numeral 1 denotes an engine body for an automobile. The engine body 1 reciprocates in a cylinder 1A (only one cylinder is shown) consisting of a plurality of cylinders and inside each combustion chamber 1B. It consists of a piston 1C that sucks the air-fuel mixture and discharges the exhaust gas after combustion to the exhaust pipe (not shown) side, and a cylinder head 1D mounted on each cylinder 1A. An intake valve 1E is provided. Reference numeral 2 denotes an intake pipe provided on the intake side of the engine body 1 and forming an intake passage communicating with the inside of each combustion chamber 1B. The intake pipe 2 is formed by an intake manifold or the like, and has a collector 2A,
It is roughly composed of a branch pipe 2B (only one is shown) that branches from the collector 2A into a plurality of pipes and communicates with each combustion chamber 1B. A throttle valve 3 located upstream of the collector 2A for adjusting the intake air flow rate is rotatably provided in the intake pipe 2.

Reference numeral 4 denotes a casing provided in the collector 2A of the intake pipe 2 via a support plate 14 which will be described later. The casing 4 has an opening 5A which expands in an arc shape on the upstream end side as shown in FIG. A casing body 6 having a bellmouth-shaped cylindrical body 5 formed with a cylindrical shape and a tapered expanded portion 6A that is arranged coaxially in the cylindrical body 5 and closes the cylindrical body 5 on the downstream end side. An injection valve housing hole 6B formed in a stepped bottomed shape is coaxially provided on the upstream side of the casing body 6. An injection valve 12 to be described later is provided in the accommodation hole 6B, and a frustoconical recess 6C is formed at the center of the end surface of the expanded diameter portion 6A. Further, the casing 4 forms an annular passage 7 between the cylindrical body 5 and the collector 2A of the intake pipe 2, and the air flow as air flowing in the annular passage 7 is passed through the outlet holes 14A described later to the casing 4 It is designed to flow out toward the downstream.

Reference numeral 8 denotes a fuel pipe provided so as to penetrate through the collector 2A in the radial direction, and one end side of the fuel pipe 8 has a tubular body 5 of the casing 4.
Is connected to the injection valve accommodating hole 6B of the casing main body 6 through, and the other end side extends outside the collector 2A. Further, the fuel pipe 8 is composed of the collector 2A and the tubular body 5 of the casing 4,
By being airtightly fixed to the casing body 6, the casing 4 together with the support plate 14 is coaxially supported in the collector 2A. The fuel pipe 8 is the intake pipe 2
Is connected to a fuel pump (neither is shown) via a pressure regulator or the like outside, and supplies fuel from the fuel pump to the injection valve 12 at a predetermined fuel pressure.

Reference numeral 9 denotes an annular branch passage formed between the casing body 6 and the tubular body 5 and located radially outside the injection valve accommodating hole 6B. The branch passage 9 has a tubular body with one end on the inflow side thereof. A mouth opening 5A of 5 forms a trumpet shape, and constitutes an intake passage together with the annular passage 7 in the collector 2A. The branch passage 9 extends in the casing 4 in the axial direction,
The other end on the outflow side communicates with each venturi hole 10 described later at the position of the expanded diameter portion 6A as shown in FIG. Further, the branch passage 9 surrounds the injection valve housing hole 6B, so that the injection valve 12 is cooled by the airflow flowing in the branch passage 9 in the direction of the arrow A.

Reference numerals 10 and 10 denote a pair of venturi holes drilled in the enlarged diameter portion 6A with a predetermined inclination angle so that the branch passage 9 communicates with the inside of the recess 6C on the downstream end side of the casing body 6. Is formed in a substantially conical shape, and a narrowed portion 10A is provided in the middle thereof. Here, each of the venturi holes 10
The inflow side, which is the large-diameter opening, communicates with the branch passage 9 as shown in FIG. 5, and the outflow side, which is the small-diameter opening, is inclined toward the downstream side and is recessed so as to face each other in the diametrical direction. 6C
It opens to the inside. Then, the respective venturi holes 10 collide the airflows from the branch passages 9 with each other on the downstream side of the recessed portion 6C, and then these airflows are directed to the downstream side of the intake passages together with the atomized fuel which will be described later. A jet pattern C having a substantially conical shape is jetted in the direction.

Reference numerals 11 and 11 denote a pair of fuel passages that are located between the injection valve accommodation hole 6B and the respective venturi holes 10 and are formed in the casing body 6 so as to be inclined outward in the radial direction. The inflow side is open to the bottom side of the injection valve accommodating hole 6B, and the outflow side is open to the vicinity of the throttle section 10A of each venturi hole 10. Reference numeral 12 denotes an injection valve mounted in the injection valve accommodating hole 6B, and the injection valve 12 supplies the fuel supplied from the fuel pipe 8 from an injection nozzle (not shown) on the tip side to each fuel passage 11 through each fuel passage 11. It is designed to be injected into the venturi hole 10 to flow out. Reference numeral 13 denotes a lid body having the injection valve accommodating hole 6B provided thereon after the injection valve 12 is attached.

Further, 14 is a support plate as a swirl forming plate provided between the casing 4 and the collector 2A at the outer periphery of the downstream end of the casing 4, and the support plate 14 is made of aluminum or the like having a predetermined plate thickness. And is formed of a metal plate for supporting the casing 4 coaxially in the collector 2A. Also,
As shown in FIG. 6, a plurality of swirl air outflow holes 14A, 14A ,.
Each of the outflow holes 14A is formed so as to incline from the inflow side toward the outflow side in the radial direction by a predetermined angle and in the circumferential direction by a predetermined angle. Then, each of the outflow holes 14A has an annular passage 7
The air flow as the air from the above is made to flow out in the direction of the arrow D, and a swirl (spiral flow) E is formed in the mixed gas of the ejection pattern C.

Here, the air flow in the arrow D direction flowing out from each of the outflow holes 14A is a mixture of the air flow in the arrow A direction in the casing 4 and the fuel injected from the injection valve 12, and has, for example, a substantially conical shape. Is almost tangentially directed toward the air-fuel mixture jetted in the direction of arrow B with the jet pattern C of No. 1, and the swirl E can be effectively generated in the air-fuel mixture of the jet pattern C. .

The fuel injection device according to the prior art has the above-mentioned structure. Next, atomization, atomization and mixing action of the fuel injected from the injection valve 12 will be described.

First, the reciprocating motion of each piston 1C on the engine body 1 side causes each combustion chamber to pass through the intake pipe 2 when each intake valve 1E opens.
The intake air sucked into 1B is branched into the branch passage 9 in the collector 2A, flows in the direction of arrow A, and is sequentially distributed into the respective venturi holes 10 in two directions. When passing through the vicinity of, the flow velocity is greatly increased and becomes a high-speed air flow. Then, the fuel injected from the injection valve 12 through each fuel passage 11 in the vicinity of the narrowed portion 10A of each venturi hole 10 is atomized until this high-speed air flow becomes assist air and has a relatively small particle size. Meanwhile, the air is primarily mixed with the intake air.

Further, the air flow primarily mixed with the atomized fuel flows out from the outflow side of each venturi hole 10 into the recess 6C, collides with each other and merges again, so the atomized fuel also collides with each other, for example, After being further atomized to a particle size of about 10 μm, the mixture is ejected in the direction of arrow B as a mixture having an ejection pattern C. Then, the air-fuel mixture having the jetting pattern C is swirled by the air flow in the direction D indicated by the arrows from each of the outflow holes 14A, and becomes a swirl flow state.
Secondary mixing while being mixed and stirred with the directional air flow, atomization,
Mixing is promoted to form a uniform air-fuel mixture, which is sequentially sucked into each combustion chamber 1B.

Thus, in the above-mentioned prior art, the fuel injected from the injection valve 12 through each fuel passage 11 is atomized by the high-speed air flow in the vicinity of the narrowed portion 10A of each venturi hole 10 to perform primary mixing, and each venturi is mixed. On the outflow side of the holes 10, they collide with each other to be further atomized and ejected as an air-fuel mixture of the ejection pattern C, and the air-fuel mixture of the ejection pattern C is swirled by the air flow from the respective outflow holes 14A in the direction D. Since E is generated, the injected fuel can be atomized to about 10 μm, atomization and mixing of the fuel can be effectively promoted over two stages, and a uniform air-fuel mixture can be supplied into each combustion chamber 1B. .

Especially, the swirl E is applied to the mixture of the ejection pattern C,
Since it is circulated to the downstream side as a vortex flow state, the penetration force of the air-fuel mixture ejected from the casing 4 in the direction of the arrow B is too strong, and the wall surface of the collector 2A or the intake port 1F wall of the cylinder head 1D etc. Even when fuel adheres as liquid droplets, the swirl E can weaken the penetration force of the air-fuel mixture to an appropriate level, and reliably promote atomization and mixing to the wall surface of the intake port 1F. It is possible to effectively prevent the adhesion of the fuel.

Therefore, the atomization and mixing of the fuel can be greatly promoted, the combustion efficiency of the air-fuel mixture can be increased, and the low-temperature startability and the idle stability can be reliably improved. Also, casing 4
And the like are provided on the downstream side of the throttle valve 3, fuel adhesion to the throttle valve 3 can be prevented, transient response can be improved, and atomization can be achieved even when compared with an ultrasonic transducer. Various effects such as an increase in the throughput of fuel and a reduction in cost can be achieved.

[Problems to be solved by the device]

By the way, in the above-mentioned prior art, the collector of the intake pipe 2 is
A plurality of swirl air outflow holes 14 are provided between the 2A and the casing 4.
Since the support plate 14 as a swirl forming plate having A, 14A, ... Is provided, when a large amount of intake air flows through each outflow hole 14A of the support plate 14 when the engine rotates at high speed, a large intake resistance is generated. However, there is an unsolved problem that a large amount of intake air cannot be smoothly supplied to the engine body 1 side, and the fuel is likely to be excessively rich.

The present invention has been made in view of the above-mentioned problems of the prior art. The present invention can smoothly supply intake air even when the engine is rotating at a high speed, and can solve the problems such as excessive fuel concentration. The fuel injection device is provided.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the present invention provides an intake passage for supplying intake air to an engine, a casing provided in the middle of the intake passage and forming an annular passage between the intake passage and the inside of the casing. An injection valve for injecting fuel supplied from the outside, a branch passage formed in the casing in the axial direction and having an inflow side opened to an upstream end of the casing, and communicating with an outflow side of the branch passage. , A plurality of venturi holes opened at a downstream end of the casing so as to face each other with a predetermined inclination angle, and the casing formed so as to open in the middle of each of the venturi holes, respectively, A plurality of fuel passages that flow out to each of the venturi holes, and air that is provided in the outer periphery on the downstream side of the casing and flows in an annular passage on the outer periphery of the casing, A swirl forming plate for swirling the air-fuel mixture ejected from the venturi hole, a bypass passage provided in the intake passage so as to connect the upstream side and the downstream side of the swirl forming plate, and the middle of the bypass passage. And a control valve whose valve opening is controlled according to the intake air amount.

[Action]

With the above configuration, since the valve opening degree of the control valve provided in the middle of the bypass passage can be controlled according to the intake air amount, a large amount of intake air can be supplied to the engine side through the bypass passage even when the engine is rotating at high speed. In addition, the intake resistance can be suppressed to a low level, and good atomization and mixed states can be obtained over the entire rotational speed range.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. Incidentally, in the embodiment, the above-mentioned FIGS.
The same components as those of the prior art shown in the figure are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, 21 is a bypass passage attached to the intake pipe 2 so as to connect the upstream side and the downstream side of the support plate 14, 22 is provided in the middle of the bypass passage 21, and flows in the bypass passage 21. 2 shows a control valve for controlling the air flow rate, and the control valve 22 is constituted by an electromagnetic duty control valve or the like, and the valve opening degree θ is shown in FIG. 2 by an opening / closing signal from a control unit 23 described later. It is controlled based on a map as a valve opening characteristic diagram. The bypass passage 21 is shown in FIG.
Although the annular passage 7 in the collector 2A and the downstream side of the support plate 14 are communicated with each other by this, instead of this, the inside of the intake pipe 2 upstream of the casing 4 and the downstream side of the support plate 14 are replaced. The bypass passage 21 may be formed so as to communicate with the inside of the collector 2A or the inside of each branch pipe 2B.

Reference numeral 23 denotes a control unit composed of a microcomputer or the like, and the control unit 23 has an input side connected to a crank angle sensor 24, an air flow meter 25, a water temperature sensor, a throttle valve switch (all not shown), and the like. Side is injection valve 12 and control valve
It is connected to 22 mag. The control unit 23 calculates the fuel injection amount based on the engine speed N from the crank angle sensor 24, the intake air amount Q from the air flow meter 25, etc., and outputs an injection signal to the injection valve 12. In addition, the program shown in FIG. 3 is stored in the memory circuit, and when the intake air amount Q by the air flow meter is smaller than the predetermined amount Q ₀ , a closing signal is continuously output to the control valve 22 and the predetermined amount Q ₀ is output. When it exceeds, it has a function of outputting a valve opening signal according to the valve opening degree θ based on the map shown in FIG.

The fuel injection device according to the present embodiment has the above-mentioned configuration, and the basic operation thereof is not different from that of the prior art.

Therefore, the control unit 23 opens the control valve 22,
The valve closing operation will be described with reference to FIGS. 2 and 3.

First, start the processing operation when the engine starts,
In step 1, the intake air amount Q is read from the air flow meter 25, and in step 2, it is determined whether or not the intake air amount Q exceeds a predetermined amount Q ₀ . Here, the predetermined amount Q ₀ means that the opening degree of the throttle valve 3 shown in FIG. 4 gradually increases and the intake air amount Q increases, and from the annular passage 7 in the collector 2A to the downstream side of the support plate 14. It corresponds to the intake air amount Q when the airflow flowing through each swirl air outflow hole 14A has a non-negligible intake resistance, for example, when the engine speed reaches the middle speed range.

When "YES" is determined in step 2, the intake resistance is generated in the air flowing through each swirl air outflow hole 14A. Therefore, the process proceeds to step 3 and the map shown in Fig. 2 is referred to. The valve opening degree θ of the control valve 22 is determined from Q, and a valve opening signal (for example, high frequency voltage) corresponding to the valve opening degree θ is output to the control valve 22 in step 4, so that the valve opening degree θ at this time is set. A corresponding amount of air is supplied to the downstream side of the support plate 14 via the bypass passage 21. As a result, the intake air flowing into the collector 2A from the upstream side of the intake pipe 2 receives the branch passage 9 in the casing 4 and the support plate.
Each of the swirl air outflow holes 14A of 14 circulates to the downstream side, and also flows through the bypass passage 21.
It is possible to prevent a large intake resistance at 14A, etc., and to smoothly supply intake air to the engine body 1 side.

Further, when "NO" is determined in step 2, the intake air amount Q is smaller than the predetermined amount Q ₀ , so that a large intake resistance does not occur in each outflow hole 14A or the like, and the control valve 22 is set in the step 5 in step 5. A valve closing signal is output to close the control valve 22. Then, in this case, the intake air can be smoothly supplied to the downstream side by the branch passage 9 and the respective outflow holes 14A, and atomization and mixing of fuel can be promoted as in the prior art.

Therefore, according to the present embodiment, the intake air can be smoothly supplied to the engine body 1 side over the entire engine speed range, and the intake resistance can be suppressed to a small level. When the intake air amount Q exceeds the predetermined amount Q ₀ after reaching the high speed range from ₀ to ₁₀ , the valve opening degree θ of the control valve 22 is increased or decreased according to the intake air amount Q at that time based on the map shown in FIG. Since the amount of air flowing through the bypass passage 21 is controlled, it is possible to continue flowing an amount of air substantially corresponding to the predetermined amount Q ₀ into the branch passage 9 and each of the outflow holes 14A, so that the entire rotation of the engine is achieved. Various effects are exhibited, such as the atomization and mixing of the fuel can be promoted over several regions, and the idle stability, low temperature startability and transient response can be improved.

[Effect of device]

As described in detail above, according to the present invention, a bypass passage that connects the upstream side and the downstream side of the swirl forming plate is provided in the intake passage, and the valve opening degree is provided in the middle of the bypass passage according to the intake air amount. Since the control valve to be controlled is provided, it is possible to prevent the intake resistance from increasing due to the swirl forming plate, etc., and it is possible to smoothly supply the intake air to the engine side. Air can be circulated through a branch passage, a swirl forming plate, or the like, and various effects such as atomization and mixing of fuel can be promoted.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a longitudinal sectional view of a fuel injection device, FIG. 2 is a characteristic diagram showing the relationship between intake air amount and valve opening, and FIG. FIG. 4 is a flow chart showing the process of opening and closing the control valve, FIGS. 4 to 7 show the prior art, FIG. 4 is an overall view of the fuel injection device, and FIG. 5 shows the main parts in FIG. FIG. 6 is an enlarged vertical sectional view, FIG. 6 is a perspective view showing a swirl formation state, and FIG. 7 is a sectional view taken along the line VII-VII in FIG. 1 ... Engine body, 2 ... Intake pipe, 2A ... Collector, 2B ... Branch pipe, 3 ... Throttle valve, 4 ... Casing, 5 ... Cylindrical body, 6 ... Casing body, 7 ... Annular passage, 8 ... Fuel pipe, 9 ... Branch passage, 10 ... Venturi hole, 11 ... Fuel passage,
12 ... Injection valve, 14 ... Support plate (swirl forming plate), 14A ... Swirl air outflow hole, 21 ... Bypass passage, 22 ... Control valve.

Claims (1)

[Scope of utility model registration request] 1. An intake passage for supplying intake air to an engine, a casing provided in the middle of the intake passage to form an annular passage between the intake passage and an intake passage, the casing being provided in the casing and supplied from the outside. An injection valve for injecting the injected fuel,
A branch passage formed in the casing in the axial direction and having an inflow side opened to an upstream end of the casing, communicates with an outflow side of the branch passage, and faces a downstream end of the casing with a predetermined inclination angle. A plurality of open venturi holes, and a plurality of fuel passages formed in the casing so as to open in the middle of each of the venturi holes, for allowing fuel from the injection valve to flow out to each of the venturi holes,
A swirl forming plate that is provided on the outer circumference of the downstream side of the casing and applies a swirl to the mixture gas ejected from each of the venturi holes by the air flowing through the annular passage of the outer circumference of the casing, and upstream and downstream of the swirl forming plate. Fuel injection including a bypass passage that is provided in the intake passage so as to communicate with the intake side, and a control valve that is provided in the middle of the bypass passage and whose valve opening is controlled according to the intake air amount. apparatus.