JPH04134176A - Fuel injecting device for engine - Google Patents

Abstract

PURPOSE:To obtain a device with a simple and compact structure laminating multiple ceramics sheets to form a main frame having multiple notches for nozzles and multiple fuel reservoirs, and providing vibrating members at parts corresponding to each notch for nozzle of the main frame. CONSTITUTION:An injecting unit A forming a fuel injecting device consists of a main frame 1, which consists of multiple ceramics sheets 1a-1d as the base material, and vibrating members 7 fitted to this main frame 1. At this stage, multiple notches 2 for nozzles and multiple fuel reservoirs 3, 4 are formed at least in the intermediate ceramics sheets 1b, 1c. On the other hand, a first layer sheet 1a is formed into a simple sheet without notch. Multiple vibrating members 7 corresponding to the notches 2 for nozzles are fitted to the top surface of a fourth layer sheet 1d. The alternating voltage signal is applied to the vibrating members 7 to transmit the vibration to parts, where the vibrating members 7 are fitted, by repeating the deformation. Furthermore, the fuel is injected from the notches 2 for nozzle by making the vibration to work to the fuel in the fuel reservoirs 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection device that injects and supplies fuel in response to a drive signal.

[Conventional technology]

Conventionally, as shown in Japanese Utility Model Application Publication No. 61-186729, for example, a fuel injection device is provided in the intake passage of an engine, and based on calculation of the fuel injection amount by a control unit, an amount of fuel corresponding to the amount of intake air, etc. is injected. Engines in which fuel is injected from the above fuel injection device are generally known. A conventional fuel injection device for such an engine is a fuel injection valve (having a valve for opening and closing an injection port, a plunger for operating the valve, a solenoid, a spring, etc.).
(injector). Then, the solenoid is energized by the injection pulse signal from the control unit for a time corresponding to the pulse width, the valve is opened by energizing the solenoid, and fuel is injected, and the fuel injection amount is adjusted according to the valve opening time. It has become so.

[Problem to be solved by the invention]

The fuel injection valve, which is a conventional fuel injection device as described above, is
It has a complex structure, consisting of many parts such as valves, plungers, solenoids, and springs, and there are limits to how compact it can be made. Additionally, if a fuel injection valve with a large amount of fuel injection per unit time is used, the accuracy will be poor in the low intake air amount region where the required injection amount is small, and if a fuel injection valve with a small amount of fuel injection per unit time is used, the intake amount will be poor. The required injection amount cannot be covered in this area. For this reason, it is considered to be equipped with multiple fuel injection valves, one for low intake air amount region and one for intake air amount region, and use them depending on the operating region. This makes it even more difficult to make the device compact.

In view of these circumstances, the present invention injects fuel using a type completely different from conventional fuel injection valves, simplifies the structure,
The purpose of the present invention is to provide a fuel injection device for an engine that can be significantly downsized.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a plurality of nozzle cutouts and a space serving as a fuel reservoir that communicates with each nozzle cutout in a ceramic sheet located at least in the middle. A fuel injection device body comprising a fuel injection device body in which ceramic sheets are laminated and sintered, and a vibrating body that is provided at a portion of the body corresponding to each nozzle notch and vibrates in response to a drive signal. It is.

In this configuration, it is preferable that the vibrating body is composed of a piezo element and is configured to give vibration by expanding and contracting in response to an alternating current signal.

[Effect]

According to the above configuration, when the vibrating body vibrates while fuel is stored in the fuel reservoir, fuel is injected through the nozzle notch due to the vibration. Fuel injection from each nozzle notch is performed by a drive signal for each vibrating body, and the amount of fuel injection is adjusted by selecting the number of vibrating bodies to be driven. The laminated structure of the ceramic sheets described above can be molded extremely compactly using hybrid IC molding technology.

Further, when the vibrating body is configured as a piezo element, vibrations can be effectively applied by an AC signal despite the compact structure.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

FIGS. 1 and 2 show an embodiment of the present invention, and FIG. 1 shows a state in the middle of forming (a stage before sintering). As shown in these figures, the injection unit A constituting the fuel injection device includes a plurality of ceramic sheets 1
It includes a main body 1 made of materials a to 1d, and a vibrating body 7 attached to the main body 1. In this embodiment, the main body 1 is composed of four ceramic sheets 18 to 1d from the first layer (lowest layer) to the fourth layer (top layer).

A plurality of nozzle notches 2 and a space constituting a fuel reservoir 3.4 are formed in at least the middle ceramic sheet among the ceramic sheets 18 to 1d, and in this embodiment, the 311th sheet 1C to the 311th sheet 1C to the 2 layer sheet 1
The above nozzle notch 2 and fuel reservoir 3.4
is formed. That is, in the third layer sheet 1c, a plurality of nozzle notches 2 located on the - side part and spaces serving as individual fuel reservoirs 3 communicating with each nozzle notch 2 are formed. , the second layer sheet 1b includes a space that constitutes an individual fuel reservoir 3 together with the space of the third m-th sheet 1c, and a space that serves as a common fuel reservoir 4 that communicates with each fuel reservoir 3 via a notch 5. , and a notch (not shown) for introducing fuel from the outside into this common fuel reservoir 4. The first layer sheet 1a is a simple sheet having no notches or the like. In addition, the fourth layer sheet 1
d also has no notches, but a plurality of vibrating bodies 7 corresponding to the nozzle notches 2 are attached to the upper surface of the fourth layer sheet 1d.

Each of the vibrating bodies 7 generates mechanical vibration in response to a drive signal, and is preferably formed of a piezo element. Each vibrating body 7 is placed at each upper position of the individual fuel reservoir 3 that communicates with each nozzle notch 2.
is installed.

Further, as shown in FIG. 3, a pair of electrodes 8 made of thick film of gold or the like are arranged for each vibrating body 7, and this electrode 8 is also placed on the fourth layer sheet 1d together with the vibrating body 7. It is installed.

To form the injection unit A, first, a four-layer ceramic unsintered sheet is formed into the shape shown in FIG. A thick film electrode 8 is bonded.

For example, an alumina green sheet can be used as the unsintered ceramic sheet, and PZT or the like can be used as the piezo element. Next, by stacking and sintering the sheets 411 above, each ceramic sheet 1
8 to 1d are integrated to form the main body 1, and
The vibrating body 7 and the electrode 8 are also integrally fixed to the main body 1.

It should be noted that microfabrication techniques known in the molding of multilayer hybrid ICs can be used to mold the injection unit A as described above, thereby making the injection unit A extremely compact.

Specifically, the width of the nozzle notch 2 can be microfabricated to about 10 μm, and the thickness of the injection unit A can be made up to several tens of μm.
The front and back width (the length in the direction perpendicular to the arrangement direction of the nozzle notches 2) can be made as small as one to several shoes.

In this way, the injection unit A is formed, and by further arranging, coupling, and integrating a large number of these injection units A, it is possible to form a sufficiently large number of nozzles to cover the fuel requirement in the high intake air volume region. An injection unit assembly having notches 2 is obtained. In this case, since the injection unit A is very small as mentioned above, for example, 100
Even if several injection units A are combined and integrated, the injection unit assembly can be formed more compactly than conventional fuel injection valves.

An example of use and operation of the injection unit A will be described next.

In the injection unit A, as shown in the schematic diagram of the fuel circulation system in FIG.
By appropriately communicating with the fuel pump 12, the fuel pump 12 is used in a state in which the fuel pumped under pressure is introduced into the individual fuel reservoirs 3 via the common fuel reservoir 4. In this state,
Although a certain amount of pressure is applied to the fuel in the fuel reservoir 3, since the nozzle notch 2 is extremely thin, no fuel is injected when the vibrating body 7 is not vibrating.

When an AC voltage signal as shown in FIG. 4 is applied to the vibrating body 7 made of the piezo element, the point a in FIG.

Due to the distortion of the piezo element according to each voltage at points b and c, deformations as shown by the broken line, solid line, and two-dot chain line in Fig. 5 occur in the part where the vibrating body 7 is attached, and by repeating this deformation vibration is given. When this vibration acts on the fuel in the fuel reservoir 3, fuel is injected from the nozzle notch 2.

In this manner, when an AC voltage drive signal is applied to the vibrating body 7, the corresponding nozzle notch 2 is driven to eject. The number of injection drives is controlled by turning on and off the drive signal for each vibrating body 7 corresponding to the large number of nozzle notches 2 in the injection unit assembly, thereby injecting fuel according to the amount of intake air, etc. Amount control takes place. In other words, when the required amount of fuel is small, fuel injection is performed from only some of the nozzle notches 2, and as the required amount of fuel increases, the number of nozzle notches 2 that perform fuel injection is increased. Then, the driving of each vibrating body 7 is controlled.

As mentioned above, the injection unit assembly as a whole is sufficiently compact and is equipped with a large number of nozzle notches 2, so that the required amount of fuel can be covered in the high intake air volume region, and one nozzle notch 2 is provided. Since the injection amount from No. 2 is minute, fuel control with 174 precision is possible.

Also, according to the conventional fuel injection valve, the particle size of the injected fuel is 20
However, according to the device of this embodiment, the particle size of the fuel injected from the nozzle notch 2 is atomized to about 10 μm, and the combustibility of the air-fuel mixture is improved.

In this fuel injection device, the shape of the injection unit A, the arrangement of the injection units A when forming an injection unit assembly, etc. may be appropriately designed depending on the location where the injection unit A is assembled to the engine. For example, when the injection units A are arranged in a ring shape as shown in Fig. 7, and a plurality of rows of these are superimposed to form an injection unit assembly, as shown in Fig. 8, By inserting it between 7 langes C and D, it can be assembled into a compact.

In the device of the present invention, the vibrating body 7 attached to the main body 1 may be any vibrating body as long as it generates vibrations in response to electrical signals, but if a piezo element is used as in the above embodiment, it may be possible to reduce the size of the vibrating body 7. It is appropriate to apply vibration effectively in response to an AC signal.

〔Effect of the invention〕

As described above, the present invention has a plurality of ceramic sheets 1-
are laminated and sintered to form a main body having a plurality of nozzle notches and a fuel reservoir, and a vibrating body that responds to a drive signal is provided at a portion of this main body corresponding to each of the nozzle notches. Because of this structure, fuel is injected by the vibration of the vibrating body, and there is no need for plungers, solenoids, springs, etc., making the structure simpler than conventional fuel injection valves. Even with the nozzle notch and vibrating body, it is much more compact than the conventional one. Furthermore, it is possible to accurately control the fuel injection amount over a wide range to 111[l], and furthermore, it is possible to atomize the fuel.

Furthermore, if the vibrating body is formed of a piezo element, it is advantageous for downsizing, and also vibrates in response to an AC voltage signal, thereby allowing effective fuel injection.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of an apparatus according to an embodiment of the present invention in the middle of molding, Fig. 2 is a sectional view after molding, Fig. 3 is an enlarged sectional view of the vibrating body mounting part, and Fig. 4 is a vibration Figure 5 is an explanatory diagram showing the deformation of the vibrating body in response to the drive signal, Figure 6 is a schematic diagram of the fuel circulation system, and Figure 7 is a diagram of the injection unit assembly. FIG. 8 is a partially cutaway perspective view showing an example, and FIG. 8 is a sectional view showing an example of the assembly of the injection unit assembly. A... Injection unit, 18-1b... Ceramic sheet, 2... Notch for nozzle, 3, 4... Fuel reservoir, 7... Vibrating body. Figure 1

Claims (1)

[Claims] 1. A plurality of nozzle notches and a space serving as a fuel reservoir communicating with each nozzle notch are formed in at least the intermediate ceramic sheet, and the plurality of ceramic sheets The main body is sintered in a laminated state,
A fuel injection device for an engine, comprising a vibrating body that is provided at a portion of the main body corresponding to each of the nozzle notches and that vibrates in response to a drive signal. 2. Claim 1, wherein the vibrating body is composed of a piezo element and is configured to give vibration by expanding and contracting in response to an alternating current signal.
Fuel injection system for the engine described.