JPH01285657A - fuel injector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection device suitable for injecting and supplying fuel into the intake passage of, for example, an automobile engine. The present invention relates to a fuel injection device that can reliably promote atomization.

[Conventional technology]

2. Description of the Related Art Generally, fuel injection devices are known 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.

There are two types of fuel injection devices of this type: one in which the injection valve is disposed upstream of the throttle valve provided in the middle of the intake passage, and one in which the injection valve is disposed downstream of the throttle valve. The fuel injected from the injection valve is mixed with intake air flowing through the intake passage to form an air-fuel mixture and supplied to the combustion chamber of the engine.

[1!1 problem that IA Akira is trying to solve] By the way, in the above-mentioned conventional technology, when the injection valve is disposed upstream of the throttle valve, the intake air flowing around the throttle valve becomes subsonic. As the flow velocity increases, the fuel from the injector is atomized by the airflow around the throttle valve and can promote atomization, but after this fuel adheres to the throttle valve, it gradually flows downstream due to the airflow. This has disadvantages such as poor transient response during engine acceleration and poor low-temperature startability. In addition, if the injection valve is placed downstream of the throttle valve, it is possible to improve transient response and low-temperature startability, but the airflow velocity decreases after passing through the throttle valve. It has the disadvantage that it cannot atomize the fuel and does not promote atomization.

On the other hand, other conventional techniques are also known in which an injection valve and an ultrasonic screw are placed facing each other in the middle of a traffic route. Due to this, fuel particles atomized to, for example, 30 to 40 mm particles become suspended in the intake passage, reducing the so-called penetration force, and due to recirculation, they adhere to the throttle valve, etc.
There is a drawback that it is not necessarily possible to improve transient response, etc., and in particular, the cost increases due to the a-sonic transducer.

The present invention was made in view of the above-mentioned drawbacks of the prior art, and can reliably promote atomization of fuel injected from an injection valve.
The present invention provides a fuel injection device that can improve both transient response and low-temperature startability.

[Means to solve the problem]

A possibility adopted by the present invention to solve the above-mentioned H problem is r! ! A casing is provided in the middle of the A passage and has an injection valve housing hole formed on the upstream side, and a casing that is located radially outside of the injection valve housing hole and extends in the axial direction within the casing, and has one end side that extends in the axial direction. A branch passage that opens at the upstream end of the casing and becomes a part of the intake passage; and a predetermined inclination angle on the downstream side of the casing such that the inflow side communicates with the other end of the branch passage and the outflow sides face each other. A plurality of venturi holes are formed with a plurality of venturi holes that cause the airflow from the branch passage to collide with each other on the outflow side and then flow out again to the intake passage; a plurality of fuel passages formed in the casing so as to open near the constriction portions of the respective venturi holes; and a plurality of fuel passages provided in the injection valve housing holes and flowing into the respective venturi holes through the respective fuel passages; and an injection valve that injects fuel.

The casing may be disposed downstream of a throttle valve provided in the middle of the intake passage, and is preferably supported within the intake passage via a fuel supply pipe.

[Effect]

With the above configuration, the air flow from the branch passage is distributed into each venturi hole, and then flows through the constricted portion of each venturi hole at high speed, and is injected from the injection valve via each fuel passage. In addition to being able to atomize the fuel, this atomized fuel collides with the airflow flowing through each venturi hole and rejoins the outlet side of each venturi hole to further atomize the fuel and atomize it. The atomized liquid is then sent into the intake passageway, and atomization and mixing can be reliably promoted.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 8.

1 to 6 show a first embodiment of the invention.

In the figure, reference numeral 1 indicates an engine body for an automobile, and the engine body l includes a cylinder IA (1
(only cylinders are shown) and reciprocate within each cylinder IA,
a piston IC that sucks the air-fuel mixture into each combustion chamber IB and discharges the exhaust gas after combustion to the exhaust pipe (not shown) side;
It consists of a cylinder head ID mounted on each cylinder head, and each intake valve IE is provided on the cylinder head 10. 2 is provided on the intake side of the engine body l,
This figure shows an intake pipe that forms an intake passage that communicates with the inside of each combustion chamber IB.The intake pipe 2 is formed by an intake manifold or the like, and includes a collector 2A and a plurality of branches that branch from the collector 2A and connect to each combustion chamber IB. It is generally composed of branch pipes 2B (only the - branch pipes are shown) that communicate with each other. A throttle valve 3 is rotatably provided in the intake pipe 2 and is located upstream of the collector 2A to adjust the intake air flow rate.

Reference numeral 4 denotes a casing provided in the collector 2A of the intake pipe 2 via a fuel pipe 8, which will be described later.As shown in FIG.
It is arranged coaxially within the bellmouth-shaped cylinder 5 in which A is formed.

It consists of a casing body 6 in which a tapered enlarged diameter portion 6A that closes off the cylindrical body 5 is formed on the downstream end side.

On the upstream side of the casing body 6, an injection valve housing hole 6B having a stepped bottom shape is coaxially provided. and,
An injection valve 12, which will be described later, is provided in the housing hole 6B, and its open end is covered with a lid 7. Further, a truncated conical recess 6C is formed in the center of the copper surface of the enlarged diameter portion 6A.

Reference numeral 8.8 indicates fuel pipes provided to diametrically penetrate the collector 2A of the intake pipe 2, and each fuel pipe 8 is connected to the injection valve housing hole 6B of the casing body 6 via the cylinder 5 of the casing 4. The casing 4 is supported so as to extend coaxially within the collector 2A. Each fuel pipe 8 is connected to a fuel pump (not shown) via a pressure regulator or the like outside the intake pipe 2, and supplies fuel from the fuel pump to the injection valve 12 at a predetermined fuel pressure. It is supposed to be done.

Reference numeral 9 indicates an annular branch passage formed between the casing body 6 and the cylinder body 5 and located on the outside in the radial direction of the injection valve housing hole 6B, and one end of the branch passage 9 is connected to the mouth of the cylinder body 5. 5A opens in a trumpet shape and forms part of an intake passage within the collector 2A. And the branch passage 9
extends in the axial direction within the casing 4, and the other end communicates with each venturi hole 1O, which will be described later, at the expanded diameter portion 6A, as shown in FIG. Furthermore, by surrounding the injection valve housing hole 6B, the branch passage 9 provides a cooling effect to the injection valve 12 by the airflow flowing in the direction of arrow A within the branch passage 9.

10.10 is a recess a! in the branch passage 9 at the downstream end side of the casing body 6. A pair of venturi holes are shown which are bored at a predetermined angle of inclination in the enlarged diameter portion 6A so as to communicate with the inside of the IBC. Each of the venturi holes IO is formed in a substantially conical shape, and a constricted portion 10A is provided in the middle thereof. It is provided. Here, each venturi hole lO has a third opening on the inflow side, which is a large diameter opening.
As shown in the figure, the outflow side, which communicates with the branch passage 9 and serves as a small-diameter opening, is inclined toward the downstream side and opens into the recess 6C so as to face each other in the diametrical direction. and,
Each of the venturi holes 10 causes the air flows from the branch passage 9 to collide with each other on the downstream side of the recess 6C, and then directs these air flows together with atomized fuel, which will be described later, toward the downstream side of the intake passage in the direction of arrow B. It is designed so that it can flow out.

11.11 is located between the injection valve housing hole 6B and each venturi hole 10, and extends radially outward in the casing body 6.
The inflow side of each fuel passage 11 opens to the bottom side of the injection valve housing hole 6B, and the outflow side opens to the vicinity of the constriction part 10A of each venturi hole 10. It's open.

Further, reference numeral 12 indicates an injection valve installed in the injection valve housing hole 6B, and the injection valve 12 receives the fuel supplied from each fuel pipe 8 through each fuel passage 11 from an injection nozzle (not shown) on the tip side. The liquid is injected into each venturi hole 10 through the venturi hole 10.

The fuel injection device according to this embodiment has the above-described configuration, and first, the atomization effect of the fuel injected from the injection valve 12 will be explained.

First, due to the reciprocating movement of each piston IC on the engine body l side, the intake air sucked into each combustion chamber IB via the intake pipe 2 when each intake valve IE is opened is transferred to the collector zA.
The flow branches into the branch passage 9 and flows in the direction of arrow A, and is sequentially distributed in two directions into each venturi hole 10, and the flow velocity is greatly increased when passing near each constriction part 10A. This creates a high-speed airflow. Then, the fuel injected from the injection valve 12 through each fuel passage 11 into the vicinity of the constriction part 10A of each venturi hole 10 is atomized until it becomes a relatively small particle size as this high-speed air flow becomes assist air. Tsutsu,
It is primarily mixed with the intake air forming an air flow.

Further, since the air flow primarily mixed with this atomized fuel flows out from the outflow side of each venturi hole 10 into the recess 6C, collides with each other, and joins again, the atomized fuel also collides with each other, for example. After being further atomized to a particle size of about 10% intestine, it is distributed in the direction of arrow B, and is passed through the casing 4.
On the downstream side of the air, it joins the airflow flowing in the direction of arrow C in the intake passage, is mixed and agitated, and is secondarily mixed in an atomized state, becoming a uniform air-fuel mixture that is sequentially inhaled into each combustion chamber IB. be done.

In this case, as shown in FIG.
The pressure gradually decreases along the characteristic line of I#P2, and gradually increases along the characteristic line of pressure PI+P2 according to the amount of fuel injected from the injection valve 12, as shown in FIG. Here, the pressure P l * P 2 indicates the pressure in the vicinity of the constricted portion 10A of each venturi hole lO, and this pressure P I * P 2 has a relationship of Pi < P2.

In this embodiment, the fuel injected from the injection valve 12 through each fuel passage 11 is transferred to the throttle part 1 of each venturi hole 10.
The injected fuel is atomized by a high-speed air flow near 0A and mixed primarily, and further atomized by colliding with each other on the outlet side of each venturi hole 10, and then mixed secondary in the intake passage. 10. By atomizing the fuel to the level of a layer, atomization of the fuel can be reliably promoted over two stages, and a uniform air-fuel mixture can be supplied into each combustion chamber IB.

Therefore, the combustion efficiency of the air-fuel mixture in each combustion chamber IB can be increased to improve low-temperature startability and idling stability, and since the casing 4 and the like are provided downstream of the throttle valve 3, the throttle valve 3 can be prevented, and during acceleration, the fuel particle size can be reduced as the intake air flow rate increases along the characteristic line shown in FIG. 5, and transient response etc. can be improved. Furthermore, as shown in FIG. 6, even if the fuel injection amount is increased, the fuel particle size can be prevented from suddenly increasing.
Compared to other conventional techniques that use ultrasonic transducers, the amount of atomized fuel that can be processed can be reliably increased, and costs can be reduced. Furthermore, the casing 4 and the like can be supported by each fuel pipe 8, making it unnecessary to use a special support member, and other various effects can be achieved.

Next, FIG. 7 shows a second embodiment of the present invention. In this embodiment, the same components as in the first embodiment are denoted by the same reference numerals, and their explanations will be omitted. The feature of this embodiment is that the enlarged diameter portion 6A of the casing body 6 is provided with one, for example, three venturi holes 21, 21.・・・
The outflow sides (not shown) of each venturi hole 21 are made to face each other in three directions in the recess 6C, and three fuel passages are provided in the casing body 6 corresponding to each venturi hole 21. 22, 22, . . .

Here, each venturi hole 21 and each fuel passage 22 are formed in the same manner as each venturi hole 10 and each fuel passage 11 described in the first embodiment except that the number is increased.

Thus, this embodiment configured in this manner can also provide substantially the same effects as the embodiments described above. Note that each venturi hole 21. The number of fuel passages 22 may be increased to four or more.

Next, FIG. 8 shows a third embodiment of the present invention.

In this embodiment, the same structures and elements as in the first embodiment are given the same reference numerals, and their explanations will be omitted.One feature of this embodiment is that each branch pipe 2B of the intake pipe 2 The reason is that each other injection valve 31t is provided. Here, each injection valve 31 is inserted into each combustion chamber IB so as to add fuel to the injection valve 12 in the casing 4 (see Figure 2) when the engine is accelerating and when the output is high. Each fuel pipe 32
It is designed to inject fuel from the That is, when the engine is idling, fuel is injected only from the injection valve 12 to form a uniform premixture to improve idle stability, and when the engine is accelerating, the fuel is injected only from the injection valve 12 and each injection Fuel is injected from the valve 31 to quickly increase the amount of fuel, thereby further improving transient response.

In this manner, this embodiment configured as described above can obtain substantially the same effects as those of the above-mentioned embodiments, but especially in this embodiment, transient response etc. can be significantly improved.

In each of the above embodiments, the casing 4 has been described as being composed of the cylindrical body 5 and the casing body 6, but the casing 4 does not necessarily have to be formed of these two members, and may be formed of a single member. In this case, it is sufficient to provide a plurality of branch passages extending in the axial direction in the casing so as to communicate with at least each venturi hole IO.

〔Effect of the invention〕

As detailed above, according to the present invention, the fuel from the injection valve is emptied through each fuel passage and injected into the vicinity of the throttle part of each venturi hole, and the outflow side of each venturi hole is mutually connected at the downstream end of the casing. Since they are configured to face each other, the fuel can be atomized and primary mixed near the constriction part of each venturi hole, and then collided with each other on the outlet side of each venturi hole to further atomize the fuel and perform secondary mixing. Atomization and mixing can be reliably promoted to form a uniform mixture. Therefore, in addition to improving idle stability and low-temperature starting performance, it is also possible to improve transient response by providing the casing etc. under the throttle valve fItOIi, and since the casing can be supported by the fuel pipe, special support members are not required. This is no longer necessary, and the intake air in the intake passage can be smoothly circulated.

[Brief explanation of the drawing]

1 to 6 show a first embodiment of the present invention, in which FIG. 1 is an overall view of a fuel injection device, and FIG. 2 is an enlarged vertical cross-sectional view of main parts in FIG. Figure 3 is a sectional view taken along the mm-m arrow in the m2 diagram, Figure 4 is a sectional view taken along the 17-IV arrow in Figure 2, and Figure 5 shows the relationship between air flow rate and fuel particle size. Figure 6 is a characteristic diagram showing the relationship between injection amount and particle size, Figure 7 is a sectional view similar to Figure 4 showing the second embodiment, and Figure S8 is a characteristic diagram showing the relationship between the injection amount and particle size. FIG. 1 is an overall view of a fuel injection device showing an example. ■... Engine body, 2... Intake pipe, 2A... Collector, 2B... Branch pipe, 3... Throttle valve, 4... Casing, 5... Cylindrical body, 6...・Casing body, 6A... Expanded diameter part, 6B... Injection valve housing hole, 8... Fuel pipe, 9... Branch passage, 10.21.
...Venturi hole. 10A... Throttle part, 11.22... Fuel passage, 12
゜31...Injection valve. Patent applicant: Japan Electronics Co., Ltd. Agent: Kazuhiko Hirose, patent attorney
Naoki NakamuraFigure 2Figure 3Figure 4Figure 5Figure 6

Claims (3)

[Claims] (1) a casing provided in the middle of the intake passage and having an injection valve housing hole formed on the upstream side; a casing located radially outside of the injection valve housing hole and extending axially within the casing;
A branch passage whose one end side opens at the upstream end of the casing and becomes a part of the intake passage; an inlet side communicates with the other end side of the branch passage, and an outflow side facing each other, and is provided on the downstream side of the casing. a plurality of venturi holes formed with an inclination angle of , a plurality of fuel passages formed in the casing so that the outflow sides open near the constriction portions of the respective venturi holes; A fuel injection device consisting of an injection valve that injects fuel into the interior. (2) The fuel injection device according to claim (1), wherein the casing is disposed downstream of a throttle valve provided in the middle of an intake passage. (3) The fuel injection device according to claim (1), wherein the casing is supported within the intake passage via a fuel supply pipe.